Experimental Biology and Medicine

Previously Saidman et al. (1) found a correlation between anesthetic potency and the oil/gas partition coefficient. Their measure of potency was the MAC, i.e., the minimum anesthetic concentration required to prevent a muscular response to a skin incision in 50% of the subjects to whom the anesthetic was administered. Schwartz and MacKrell (2) showed that the percentage of anesthetic needed to produce a given decrease in the H⁺ secretory rate of frog gastric mucosa in vitro was proportional to the MAC in man and on this basis predicted the MAC values for chloroform and Compound 347 (Ethrane). These results suggested lipid solubility as a factor influencing the potency of anesthetics in inhibition of acid secretion.

In the work above (2) on frog gastric mucosa the anesthetics had molecules with no more than four carbon atoms. Mullins (3) points out that for compounds with more than four carbon atoms the anesthetic potency declines and that by the time one reaches a compound of C₁₀ or C₁₂ an anesthetic series is inert and higher analogues, whether they be alcohol, ether, or paraffin, have no anesthetic activity. Hence it is inferred that there is a site size limit for anesthetic molecules in biological membranes. In contrast, other investigators (4) found that the hypnotic activity of narcotics such as barbiturates was closely related to their relative lipophilic character as defined by the logarithm of the octanol-water partition coefficient, log P. Consequently, it was of interest to compare the behavior of barbiturates with anesthetics under similar conditions, namely, their effects on frog gastric mucosa. The question then is: to what extent is lipid solubility of barbiturates as defined by log P indicated as a factor in inhibition of acid secretion.

A simple reproducible assay for mitochondrial α-GPD has been described. It takes advantage of the ability of INT to accept directly electrons from the dehydrogenase. The assay as described measures accurately enzyme activity using 20 μg of mitochondrial protein, but it could be scaled down for smaller quantities of protein by using smaller reaction volumes and microcuvettes.

We have described for the first time a technique for demonstrating human properdin in whole serum by immunoelectrophoresis. Utilizing this method, we have noted a change in the immunoelectrophoretic migration of properdin by incubating serum at 37°. There was a concomitant decrease in the functional activity of properdin and CH50, as well as conversion of β1C to a β1A pattern on immunoelectrophoresis. It is probable that the changes in the electrophoretic mobility of properdin resulted from a fundamental change in the properdin molecule.

The authors wish to acknowledge the expert technical assistance of Kay Townsend.

Leukocyte colonies derived from canine bone marrow show different rates of growth and cytological differentiation when grown in the presence of different serum environments. Minimal formation of mature granulocytes was observed with fetal calf serum (FCS) alone compared to that observed with dog or human serum. The growth kinetics and composition of canine leukocyte colonies are dependent upon the source of colony stimulating activity used. This system may be useful in assessing granulopoietic factors in canine and human serum.

We are grateful to Iola Menna and Delphine Jackson for technical assistance.

Intravenous administration of E. coli endotoxin to anesthetized dogs caused a precipitous fall in arterial blood pressure and renal artery flow within 3 min. With the fall in blood pressure, plasma ³H-norepinephrine fell to 63% of control levels. Five minutes after endotoxin administration, the ³H-norepinephrine level increased to 90% of the control value. Thirty minutes after endotoxin administration, blood pressure had risen to 75% of control levels and ³H-norepinephrine remained unchanged. ³H-Norepinephrine concentration in the atria, ventricle and kidneys remained unchanged, but the levels in the spleen and adrenals were significantly increased. In all cases ³H-normetanephrine levels increased suggestive of increased release and metabolism of catecholamines. It is suggested that endotoxin exerts certain changes in cellular permeability resulting in increased extraction of norepinephrine from the circulating blood.

It has recently been claimed that a pituitary peptide which inhibits several phases of carbohydrate and lipid metabolism is identical with the COOH-terminal 25-amino acid portion of human growth hormone. However, the active factor has always been obtained in low yield and impure condition. We have used cyanogen bromide to prepare the COOH-terminal 21-amino acid peptide of human growth hormone. This fails to inhibit any of three systems inhibited by the reputed active fraction: glyceraldehyde 3-phosphate dehydrogenase, α-glycerophosphate dehydrogenase, and glucose uptake by rat soleus muscle. Unless the first four amino acids are essential, the identification of the inhibitory factor as the COOH-terminal 25-amino acid peptide of human growth hormone is not justified.

The author thanks Dr. David Scott of Auckland Public Hospital for the supplies of human growth hormone. He also appreciates the helpful suggestions and encouragement of Dr. J. Nielsen and Professor J. G. T. Sneyd. Mr. I. C. T. Lyon performed the amino acid analyses.

The relation between contractile activity and Ca movements was studied in the frog heart by a method which permitted the continuous determination of cellular ⁴⁵C uptake and of tension. In Ringer solution, stimulation increased ⁴⁵Ca uptake but the extra uptake per beat was too small to explain the initiation of the contraction by itself, indicating the presence of an intracellular Ca store. In Ca-rich solution (30 mM) acetylcholine increased ⁴⁵Ca uptake in quiescent preparations and at the same time induced or increased a contracture. Epinephrine also increased ⁴⁵Ca uptake under these conditions, but caused a rapid drop in tension. These results suggest that both drugs increase the permeability of the membrane for Ca (P _ca); the inhibitory action of epinephrine may be due to increased intracellular storage of Ca.

This work was supported in part by U.S. Public Health Service Grants AM 0257-011 from the National Institute of Arthritis and Metabolic Diseases, and HE 09884 from the National Heart and Lung Institute.

Activation of the Epstein-Barr virus (EBV) genome by 5-bromodeoxyuridine (BUDR) in “virus-free” Raji or NC₃₇ cells resulted in the synthesis of early viral antigens (EA) detectable by immunofluorescence. A high proportion of sera (65-97%) from patients with infectious mononucleosis, Burkitt lymphoma and nasopharyngeal carcinoma reacted with these antigens while only 1/3 of the sera from healthy persons were reactive. Forty to 80% of sera from subhuman primates also contained anti-EA antibodies. The significance of these antibodies in man in relation to EBV infection or associated illnesses remains obscure. EA appeared to be immunologically distinct from EBV-related soluble complement-fixing antigens. BUDR activation of Raji or NC₃₇ cells offers a simple and convenient method of obtaining EA preparations free of viral capsid antigens.

The effect of 17β-estradiol on folate coenzyme metabolism was studied in normal and castrated female rats. The capacity of conversion in vivo of folic acid into activated forms was investigated by measuring the quantity of folate derivatives in the urine and the liver folate coenzyme contents after injection of folic acid. An increase in the urinary excretion of folate metabolites and a decrease in the liver content of reduced folate forms in castrated rats was seen compared with normal rats. Treatment of castrated animals with 17β-estradiol were corrective. The enzymic activities involved in the folate coenzyme metabolism were assayed in vitro both in the liver and in the uterus. Severe alterations were observed in the enzymes of castrated animals and here, too, 17β-estradiol administration restored the biochemical lesions almost completely. The results show a possible influence on folate coenzyme synthesis by 17β-estradiol.

Nucleic acid preparations from unpurified concentrates of Newcastle disease virus, Sindbis virus and Semliki Forest virus were found to contain up to 2% double-stranded RNA. Double-stranded RNA was identified by reaction with antisera specific for double-stranded RNA, capacity to protect primary rabbit kidney cells against virus infection, and relative ribonuclease resistance. The presence of such double-stranded RNA in virus preparations provides an explanation for how inactivated crude suspensions of single-stranded RNA virus virions may induce interferon in the absence of detectable viral replication.

Serologically active double-stranded RNA was also detected in normal chick embryo cell nucleic acid extracts. This differed greatly from double-stranded viral RNA, however, since the serologic activity was more sensitive to destruction by ribonuclease than the viral dsRNA and it did not stimulate resistance to virus infection in primary rabbit kidney cells.

The authors are indebted to W. P. M. Fisher, Marilyn Johnston, Mary-Ellen Davies, and Helen Perry for excellent technical assistance.

Observations were made of comparative litter and reproduction characteristics of two H-2 genotype substrains of mice within each of two lines. Two substrains (H-2^f and H-2^k) were from 45 generations of X-irradiated male progenitors, and two were from F₄₅ nonirradiated progenitors. No cumulative radiation-induced genetic decrement was noted in irradiated line mice of either H-2 substrains. A comparison of F₆ with F₄₆ data showed no degradation in reproductive fitness during 40 generations of X-ray exposure. The F₄₆ data suggest that a single gene effect on weaning weights may exist.

We acknowledge Gary L. Tietjen of the Statistical Group of the LASL Computer Division for data analysis.

Spectrofluorometric assays were carried out on the blood fractions and some cardiovascular tissues of both sexes of chickens, ducks and pigeons to determine histamine levels. Cardiac tissue histamine ranged between 0.15 and 5.82 μg/g in both females and males of these three species; the chicken had the highest concentration. Atrial tissue histamine was higher than that found in the ventricles; males usually had higher concentrations than females. The relevance of these values to other biogenic amines are discussed. Splenic histamine ranged from 3.17 to 15.21 μg/g; the female had higher values than the males. Of all the blood fractions, the white blood cells contained the highest levels; the plasma contained the least. Histamine concentration in whole blood ranged from 0.33 to 0.90 μg/ml in chickens, 0.07 to 0.14 μg/ml in ducks, and 0.02 to 0.09 μg/ml in pigeons. The blood fractions of female birds showed higher histamine values than those of males.

A partially purified enzyme from human uterine tissue was found to cleave peptides specifically at the carboxyl side of proline residues when arginine-vasopressin, oxytocin, and Ile⁵-angiotensin II were tested as proline-containing substrates. The enzyme has a pH optimum of 7.4; its activity is not affected by Mn²⁺ or Mg²⁺ (10^-6 to 10^-3 M).

The authors thank Dr. T. D. Kerenyi for his active participation and interest in this work. The technical help of Mrs. I. Mintz was appreciated.

Organ and body mass changes in restrained adult, male domestic fowl were compared with tissue from control and fasted animals. Body mass loss rate in the restrained animals was 63.5% (p < .001) greater than in the fasted group, yet the two groups recovered at the same rate. Compared with controls and fasted animals, restrained fowl exhibited an increase in size of heart, lungs, kidneys, liver, and adrenals but a greater loss of spleen, superficial pectoral muscle, small intestine, and pancreas masses. Relative water content of organs generally increased in restrained and decreased in fasted animals. The data suggest that restraint—although accompanied by inanition—affects organ and body mass in the domestic fowl in a different way than does fasting.

An association of lipid with the virus of scrapie was examined by quantitating the effects of ether, chloroform and fluorocarbon on infectivity. Treatment of infected brain suspensions with ether reduced infectivity up to 2.2 log₁₀ mouse LD₅₀. Chloroform had less effect than ether on the virus, and only a slight loss resulted from partial purification with fluorocarbon. In addition, substantial infectivity resisted sequential treatments with fluorocarbon and chloroform. The results suggest that scrapie virus was present in both solvent-sensitive and solvent-resistant forms, and that the latter probably did not contain lipid as an essential component. The infectivity of ether- and chloroform-treated preparations was not restored by addition of, or sedimentation with, normal, homologous brain suspensions suggesting that ether-sensitive helper substances were not present in normal mouse brain homogenates.

The author thanks Drs. William Hadlow and Lawrence Sturman for helpful discussion, Mr. Richard Kennedy for technical assistance, and Drs. Wallace Rowe and William Hoyer for suggestions regarding the manuscript.

Eighteen young female rabbits 6-13 mo old, and 28 aged rabbits 49-72 mo old, were randomized into three treatment groups. Group 1 does were ovariectomized and sacrificed 14 days later. Groups 2 and 3 were sacrificed 12 and 24 days post-coitum (pc), respectively. Net progesterone-7-³H and 17β-estradiol-4-¹⁴C uptakes were determined for uterine tissue strips incubated at 37° for 0, 2 and 4 hr by correcting for skeletal muscle incubated similarly.

Net uterine uptakes of progesterone-7-³H and 17β-estradiol-4-¹⁴C were greatest in the ovariectomized does and decreased particularly in the young does with increased time pc. Of most significance was the two- to fourfold greater uptake of both steroid hormones by uteri from young does than old does after 2 and 4 hr of incubation in the ovariectomized group and after 4 hr of incubation in the 12 day pc group. By 24 days pc steroid hormone uptake was low in both groups and not significantly different. The reduced capacity of uterine tissue in aged rabbits to take up steroid hormones is interpreted to be one of the uterine factors limiting reproductive performance in aged does.

We thank Dr. James D. McCaffree for help in the statistical analysis and Miss Gloria Shawver for assistance in preparing the manuscript.

SK&F 40491, a triazinoindole, provided antiviral activity when administered intranasally to gibbons infected with human rhinovirus type 2. The compound was effective in a multidose regimen either as a 0.02% solution or a 2.5% suspension. The effect of drug treatment was demonstrated by a decrease in the quantity of virus recovered from the nose, and by a decrease and delay in serum and nasal antibody response when compared to placebo-treated animals (p < .05).

Oral treatment with SK&F 40491 at 16 mg/kg/dose in a multidose regimen did not significantly inhibit viral replication or alter the characteristic antibody response in gibbons infected with rhinovirus 1A when compared to a pooled bank of placebo controls.

The authors thank Dr. S. M. Free, Jr., for biostatistical analyses, and Messrs. B. Zabko-Potapovich, P. Ferry, and P. Sereni for excellent technical assistance.

SK&F 40491, a triazinoindole, exhibited a broad spectrum of antiviral activity in vitro, notably against picornaviruses. Its activity was selective, and was observed at concentrations well below cytotoxic levels.

We are indebted to P. Ferry, B. Zabko-Potapovich, and B. Zappala for technical assistance.

⁸⁶Rb transport was studied in normal and DMD RBC. ⁸⁶Rb transport in both groups was found to be inhibited equally by ouabain even in the presence of homologous plasma. These data fail to demonstrate an intrinsic or extrinsic (plasma-induced) modification of ouabain inhibition of ⁸⁶Rb transport in DMD RBC.

This work was supported by a grant from NIH, GM 01998-03, Social and Rehabilitation Service Grant No. 16-P-56810/5-09, the Minnesota Heart Association and the Graduate School, University of Minnesota.

The agar culture method for growing colonies of granulocytes and macrophages from bone marrow cells has provided a technique for assaying a humoral factor, the colony-stimulating factor (CSF), which is found in plasma (1) and urine (2). This factor appears to be similar to CSF produced by feeder layers of bone marrow (3), peripheral leukocytes (4) or kidney cells (5). In general, colonies of bone marrow do not form unless this stimulant is continually present. Shad-duck and Nunna (1) found elevation of CSF in serum only during experimentally induced neutropenia, favoring the view that CSF is a humoral regulator of myelopoiesis.

Although serum does not usually stimulate bone marrow colonies, Bradley, Metcalf and Robinson (6) found CSF in serum of AKR mice when leukemia developed. Bradley and Siemienowicz (7) also reported stimulation of rat bone marrow by normal rat serum. In both cases, however, fetal bovine serum was used in the culture. The question of whether normal serum can stimulate bone marrow without interaction with some other factor has not been resolved.

We have developed a liquid tissue culture system for the study of bone marrow stimulants. In this system proliferation begins by the second day and reaches a peak on the third or fourth day (unpublished data) which is equal to or greater than that of the original specimen. Macrophage transformation is prominent by day two and is complete by day seven. We have found that conditioned media or heterologous sera are not required for marrow growth. However, conditioned medium can be shown to have a synergistic effect with serum when serum is limiting.

Materials and Methods. One milliliter of bone marrow aspirate from an unanesthetized calf 1-8 wk old was dispersed in 200 ml of cold Eagle's minimal essential medium (MEM) without anticoagulant and collected by centrifugation.

Synthesis of the heavy immunoglobulin chain is controlled by two genes, one being in control of the variable, the second in control of the constant portion of the chain (1-3). Elucidation of the relation between the genes for constant and variable portions of the heavy chain and of the mechanism of assembly are crucial for an analysis of the generation of antibody diversity.

Structural and genetic studies of the heavy chain can be greatly facilitated by reagents for the identification of genetic markers of the constant and variable chain segments. Allotypic specificities provide such markers: the Fd, variable portion is characterized by three specificities A1, A2, A3, controlled at the Aa locus by three respective alleles (4, 5). The constant, Fc portion of the gamma chain is characterized by two groups of allotypic specificities, Ad and Ae (3, 6, 7). Within each group two specificites, controlled by two allelic genes, have been described. All three loci, Aa, Ad and Ae are closely linked with each other. Recombinants have been observed, both between Aa and Ad (8) and between Aa and Ae loci (9).

So far, only limited population studies on the genetics of the Aa allotypes have been reported (10, 11) and even less information is available on the Fc gamma specificities (Ad and Ae). Since we were in possession of a rather unique collection of rabbit sera which represented a random-bred, panmictic and unselected population, it was decided to use this collection in the present study. We concentrated on the specificities controlled at the Aa and Ae loci and intended to answer the following questions: (a) Can the genes within each group or “locus” be regarded as true alleles?

Metabolic responses to exercise were determined in adrenalectomized and sham-operated rats. Exercised animals were forced to run 1/4 mile in 30 min each day for 8 wk. All animals were fed ad libitum at 48% protein, 28% fat, 15.5% carbohydrate diet. Extra (0.9%) NaCl was added to the diet given to the adrenalectomized rats. Under these experimental conditions, exercise reduced body weights gains to a similar degree in both the adrenalectomized and sham-operated animals and similarly lowered liver fat, liver cholesterol and serum insulin. No differences in food intake, body weight gain, blood glucose, serum insulin, carcass protein, or serum triglycerides were observed with the removal of the adrenals. Adrenalectomy did, however, affect the percentage carcass fat and the level of cholesterol in the livers of the sedentary animals. From this data it was suggested that two separate mechanisms exist for the mobilization of carcass fat: one activated by exercise and the other by the adrenal hormones.

The authors express their appreciation to Mrs. Ensook Koh for her technical assistance and to Dr. Richard Ahrens, College of Home Economics, University of Maryland for the use of the treadmill.

A fibrohemangiosarcoma was produced in hamsters following the injection of cell inocula. These tumors in pregnant, lactating female hamsters attained a wet tumor weight 4-8 times greater than that noted in either adult male or female hamsters within 6-7 wk.

Monolayer cell cultures obtained from a fibroma produced by the injection of cells from a Wistar Institute HE-44 culture in its 69th passage was alternately repassaged through inbred Syrian hamsters. Following the fourth animal repassage a culture line was obtained which consistently through the 16th subculture produced tumors composed of spindle cells, endothelial cells and cells intermediate between these two types of cells. It is considered likely that the culture line consisted of mesenchymal cells that have retained some degree of pluripotentiality. Strong acid phosphatase, β-glucuronidase and nonspecific esterase activity was present in the cells of the tumor tissue as well as in the cells grown in culture for 16 passages. It is probable that hormonal influences associated with growth are responsible for the observed differences in wet tumor weight in pregnant and nonpregnant hamsters. This tumor showed histologic resemblance to the human Kaposi sarcoma.

The transplanted rat chloroleukemia cytologically similar to human acute myelocytic leukemia is associated with markedly elevated serum and urinary muramidase levels. Current metabolic studies demonstrate excessive potassium loss in the urine and appears to be related to the degree of muramidasuria. The experimental myelogenous leukemia furnishes an excellent model for the investigation of the enzyme effect on the kidney and present studies suggest that muramidase causes a direct tubular damage.

The influence of tolerance, developed by the daily intraperitoneal administration of sublethal doses of Salmonella enteritidis endotoxin, on the endotoxin detoxifying capacity of the liver and spleen was evaluated. Liver and spleen homogenates from endotoxin-tolerant mice possessed greater endotoxin detoxifying ability than liver and spleen homogenates from saline-treated mice.

These findings further accent the importance of the liver and spleen macrophage cells in endotoxemia and indicate that endotoxin tolerance is associated with the enhanced capacity of the reticuloendothelial cells to detoxify endotoxin.

The presence of extramitochondrial CO₂/HCO₃ ^- dependent fatty acid synthesis in Ehrlich hyperdiploid ascites tumor cells cultivated in vitro was demonstrated by the stimulatory effect of increasing CO₂ tensions (0-5% atm) on the ¹⁴C-acetate incorporation into hexane extracts of KOH hydrolysates of intact cells.

The incorporation of ¹⁴C-acetate into fatty acids of particle-free supernatants of Ehrlich ascites tumor cells propagated in vivo was shown to be dependent on NADPH regenerating systems, such as citrate-isocitrate, glucose or glucose-6-phosphate. The last two compounds, however, stimulated the ¹⁴C-acetate as well as the ¹⁴C-acetyl-CoA incorporation into fatty acids even in the presence of citrate-isocitrate + NADP. Under the same conditions fructose-1,6-diphosphate produced an inhibition of the acetate incorporation.

Determinations of the NADPH concentration of particle-free supernatants fortified with different NADPH generating systems showed that only glucose and citrate-isocitrate could stabilize the NADPH level, while fructose-1,6-diphosphate and pyruvate would lower or completely exhaust the NADPH content.

The mechanism of the stimulatory effect of glucose on acetate incorporation in particle-free supernatants is discussed.

The effects of intravenously administered DMSO and Tween 80 were studied in autosexing pigeons on normal and high-cholesterol diets. These drugs, alone or in combination, did not have a significant effect in the dosage employed on aortic cholesterol content, serum cholesterol and triglyceride levels, or incidence of coronary artery atherosclerosis. Although previous reports have shown that these surface-active drugs can reduce the severity of atherosclerosis (Tween 80) or serum cholesterol levels (DMSO) in other species, these conclusions in autosexing pigeons were not supported under the conditions used in this study.

The incorporation of serum and plasma from patients with AGL into an in vitro culture system failed to influence colony formation by cells of normal bone marrow as well as those from patients with AGL. The significance of these changes and the further approach to the problem have been discussed.

A number of unsaturated phospholipids were found to be selective inhibitors of Staphylococcus aureus delta hemolysin. This inhibitory effect was manifest promptly after addition to delta hemolysin.

A synergism between alpha and delta hemolysin was evident in the kinetics of rabbit erythrocyte lysis.

The poorly developed lymphoid system of germfree guinea pigs did not prevent the development of contact sensitivity and immunologic tolerance to two simple chemicals, dinitrochlorbenzene and dinitrothiocyanatebenzene. Germfree animals responded in a manner similar to conventionally reared animals when these chemicals were applied to the skin or injected in complete Freund's adjuvant.

We thank Mr. Michael Hooton for his technical assistance and Miss Theresa Wilson for carrying out the serum protein electrophoreses.

Low zone tolerance to BSA in CAF₁ mice appears to be more a specific active immunosuppressive effect than an immunocyte clone-loss phenomenon. Quantities of normal syngeneic splenocytes able to immunologically reconstitute lethally X-irradiated mice failed to break the low zone tolerance, and similar cells obtained from immunized donors did so only partially. Furthermore, spleen cells were able to transfer this tolerance adoptively not only into immunologically deficient X-irradiated recipients but also into immunologically intact normal recipients. These data suggest that this low zone tolerance may be an example of antibody-mediated immunosuppression.

The distribution of PC and PEPck in dog liver and kidney cortex has been determined. Kidney PC is totally mitochondrial and liver PC is 60% mitochondrial. Kidney and liver PEPck are also predominately of mitochondrial origin (60-70%), while 15-16% is nuclear, and 25-30% is in the soluble fraction. It is concluded that since this distribution is similar to that found in guinea pig, rabbit, and human, the mitochondrial regulation of gluconeogenic precursor synthesis may also be similar.

A number of reports in the recent literature have suggested the possibility of persistent hypothalamic control in acromegaly (1-3), and further that a primary pathogenetic defect may be characterized by excessive secretion of hypothalamic growth hormone releasing factor. In a previous communication from this laboratory we have shown greater in vitro release of monkey pituitary growth hormone in the presence of acromegalic plasma than in the presence of normal plasma (4). It is the purpose of this report to further characterize this observation.

Methods Intact rhesus monkey pituitary glands were obtained and handled in a manner previously described (4). The incubation mixture of 10 ml included lactated ringers 7.5 ml, containing 50 μg/ml neomycin, and a glucose concentration of 100 mg/100 ml, to which 2.5 ml aliquots of plasma or dialysates of plasma with added albumin were added for study purposes. All incubations were carried out in a Dubnoff shaker at 37°, aliquots for immunoreactive growth hormone were obtained at 30 sec after the start of an incubation, during and at the conclusion of two hour incubation periods. Growth hormone was assayed using minor modifications of a solid phase radioimmunoassay (5), with highly specific rabbit anti-growth hormone antibodies, produced in our laboratory. The standard is purified human growth hormone, NIH HS-1147.

Three types of experiments were carried out. In one, whole pituitaries were incubated for 2 hr periods, first either in the presence of normal or acromegalic plasma, washed and transferred to a different plasma and then finally back to the original medium. Three intact glands were started first in acromegalic plasma, transferred to normal plasma and back for the final 2 hr of incubation to acromegalic palsma. Two pituitary glands were incubated in reverse order.

Basal serum immunoreactive insulin (IRI) levels fell promptly and in parallel with the decline observed in circulating glucose levels when alcohol was administered intravenously to fasting man. Hypoglycemia and the decrease in basal insulin secretion were associated with an initial transient increment in growth hormone levels and sustained lipolysis manifested by increased free fatty acid, glycerol and acetoacetate concentrations. These findings may result from activation of the sympathetic nervous system which is known to be operative in other hypoglycemic states.

A number of DNA binding drugs which sensitize living cells to the action of alkylating agents and X-rays have been shown to inhibit the uv-stimulated incorporation of tritiated thymidine by normal human lymphocytes incubated in the presence of hydroxyurea.

It is proposed that such DNA repair inhibiting drugs may have a role in tumor therapy when used in conjunction with alkylating agents or X-rays.

An increased response to iv angiotensin occurs in rats from 10 to 20 hr after ureteral ligations or nephrectomy. During this time there is also a rise in plasma K and a marked fall in Na/K ratio. It is suggested that the vascular bed is more sensitive to the action of angiotensin when the ionic shift has taken place in the plasma.

Adult rats made diabetic with streptozotocin had an increased concentration of brain free glutamate and glycogen but showed no changes in brain free alanine and glycine. These alterations paralleled higher circulating levels of glucose and ketones. Conversely, starved rats accumulated glycine and glutamate in the brain, although glycogen stores were not affected.

Experiments on rats indicate that lithocholic acid-induced changes in the liver and choledochus, as well as the associated bile concrement formation, icterus, loss of body weight and mortality, are all inhibited or abolished by certain catatoxic steroids (PCN and CS-1) as well as by thyroxine and triiodothyronine. Prednisolone and triamcinolone have an opposite effect. Among the classic hepatic microsomal enzyme inducers, diphenylhydantoin is ineffective, and phenobarbital is much less potent than PCN or CS-1 in influencing the toxicity of lithocholic acid.

The author thanks the Companies listed in the Materials and Methods section for kindly donating the compounds used in this experiment.

A cell line designated as MME, was established from the embryo of a pouch-less South American marsupial, Marmosa mitis. The cells were mostly fibroblastic in shape and displayed contact inhibition. Cytogenic evaluation revealed a simple karyotype (2n = 14) and large chromosomes. Growth curves of MME cells at passages 22 and 31 showed a relatively short doubling time of 20 hr. The MME cells had a fairly wide viral spectrum. Vesicular stomatitis, influenza A, infectious bovine rhinotracheitis, myxoma and bluetongue viruses were all capable of replication in this cell line.

Absorption rates of certain poorly lipid-soluble compounds across the isolated rat intestine increase substantially and continually with time (1), apparently due to progressive loss of structural integrity of the epithelium (2). However, loss of structural integrity has little effect on the absorption rates of certain nonpolar, lipid-soluble compounds suggesting that the epithelium is not a critical barrier to the intestinal absorption of such compounds (1). In the present study, this hypothesis was tested directly by comparing the in vitro and in situ flux of various solutes across the normal intestine of the rat and across the rat intestine in which the epithelium was substantially disrupted. The epithelial border was found to be a critical anatomical barrier to the in vitro and in situ intestinal absorption of both charged and uncharged poorly lipid-soluble compounds. However, contrary to the prevailing view (2-4), our studies also showed that the intestinal epithelium is not the rate-limiting barrier to the passive diffusion of rapidly absorbed, freely lipid-soluble compounds.

Methods. Intestinal transfer rates were determined in vitro with everted jeunal segments (10 cm in length) from fasted male Sprague-Dawley rats (weighing about 250 g) using a modification (5) of the method of Crane and Wilson (6), (condition I). Two milliliters of a modified physiologic Krebs bicarbonate buffer (pH 7.4) were placed inside the everted sac (serosal solution) and the entire preparation was placed in 100 ml of buffer solution containing a test compound (mucosal solution) which was continually gassed with O₂:CO₂ (95:5; v/v) and maintained at 37°. The serosal fluid was quantitatively sampled every 10 min for 30 min and each sample was assayed for the test compound. Aniline, salicylamide, salicylate, sulfanilamide, pyridine aldoxime methiodide, riboflavin and methyl orange were assayed as previously described (7).

To determine the effect of dietary magnesium deprivation on intestinal calcium transport by the rat intestine, experiments were performed using an in vitro everted gut sac technique as a measure of transport. Despite the development of hypercalcemia, no increase in the ability of the intestine to transport calcium was demonstrated. The results suggest that the hypercalcemia may be mediated by a mechanism independent of an adaptive increase in intestinal calcium absorption.

The author gratefully acknowledges the assistance of Patricia Stubbert, Paula Ennis and Anne Montague.

Prostaglandin F_2α was found to increase the lower esophageal sphincter pressure in the intact opossum in vivo. Dose response curves of the effect of PGF_2α showed that maximal response occurred with a dose of 4 μg/kg. The maximal response with gastrin pentapeptide occurred with a dose of 2 μg/kg for its action on increasing the lower sphincter pressure.

We thank Dr. John Pike of the Upjohn Company for a generous gift of prostaglandin and the Ayerst Company for gastrin pentapeptide.

Dextran released histamine in a selective manner from suspensions of normal rat peritoneal mast cells. Some characteristics of the release reaction are described. The quantity of histamine released by dextran was reduced about 50% by the presence of isoproterenol (10^-8 M), epinephrine (10^-7 M) or norepinephrine (10^-6 M). Propranolol but not phenoxybenzamine abolished the isoproterenol effect. Prostaglandin E₁ (10^-5 M) also partially inhibited histamine release by dextran. Theophylline and dibutyryl cyclic AMP also produced a dose-related inhibition of the release, which reached 50% effectiveness at about 2 × 10^-4 M concentration. Effects of several miscellaneous drugs are also described. The results obtained with the principal drugs indicated that the release reaction might be modulated by cyclic AMP.

I am grateful to Mr. Ronald Adamik for his excellent technical assistance.

Amino-oxyacetic acid (AOAA), chlorpromazine, and Dilantin were examined for their effects on acoustic priming of audiogenic seizures. AOAA administered before priming exhibited a protective effect, increasing the severity of subsequent audiogenic seizures. Dilantin had opposite effects, suggesting that the increase of brain levels of GABA provided by all three agents was not causally related to their effects on priming. Nembutal had an effect similar to that seen with Dilantin, and it was proposed that the active drugs exerted their influence by altering the threshold of the auditory transducer.

The quantity of alcohol consumed by young miniature swine was determined as a function of dietary protein and caloric intake. Pigs were fed 16% or 8% protein diets at two levels, the upper level being twice the lower level. Animals eating the 16% protein diet consumed more alcohol than those animals fed the 8% protein diet. Animals fed the lower food levels obtained a greater percentage of calories from alcohol than animals fed the upper food levels. Pigs fed the 16% protein diet at the lower level obtained 40% of total calories as ethanol. Orange juice was preferred by pigs as a carrier of ethanol over cola or water.

Marijuana extract distillate enhanced shuttle-box avoidance of rats with a previously established base line of poor performance. When drug was discontinued, performance returned to base line. Marijuana facilitated acquisition of avoidance behavior; performance level was maintained after treatment ended. The data suggest that the facilitative effect is due to an action of the drug different than that which causes depression of conditioned behavior.

The effect of aminophylline on the coronary vasodilator effect of adenosine and myocardial reactive hyperemia following different periods of coronary occlusion was studied in 5 anesthetized dogs. It has been shown that aminophylline decreases the volume and duration of hyperemic flow produced by adenosine approximately 41 and 11%, respectively, and by ischemia, approximately 42 and 31%, respectively. These results support the concept that adenosine is possibly a metabolic mediator in the regulation of coronary blood flow.

The present study indicates that production of CHIK and DEN-1 viruses in BHK-21 cells were inhibited by lowering NaCl concentrations of culture media. The inhibitory effect was reversed rapidly (within 30 sec) by placing the cells in normal medium. By changing the media from normal to low NaCl concentrations, the inhibition of virus release again took place within short periods of time. In this manner, the inhibition of virus release and its recovery could be repeated practically indefinitely in a particular culture. The effect was due to the ionic strength rather than osmolarity of media. No substances other than the salt such as amino acids or culture medium ingredients were regarded to be involved.

While the present data are compatible with those previously reported with viruses of Sindbis (3) and polio (2), some unique findings were obtained in our electron microscopic studies. The cells cultured in low ionic strength media did not reveal characteristic pictures of viral budding from the cell surface membrane as commonly seen in cells cultured in normal media. In spite of it, the “precursor particles” (8, 9) were observed in the cells cultured in low ionic strength media as in normally cultured cells. As generally accepted (7-12), the group A arboviruses acquire their outer coat from the cell surface membrane of host cells during the budding stage. The ionic strength seems to influence this process, altering certain biochemical and/or biophysical conditions of the cell membrane structures. This may have a significant relation with the mechanism of virus release from host cells such as observed with Western equine encephalitis virus in chick embryo cells (13) or Venezuelan equine encephalitis virus in KB cells (14).

Single threshold stimuli were delivered to the endocardium during early diastole in 11 dogs hourly following multistage balloon occlusion of the left anterior descending coronary artery. RVR could be evoked in all but one animal with a mean appearance time of 3.7 hr after coronary occlusion and preceding onset of spontaneous VT by an average of 2.5 hr. The RVR phenomenon may be helpful in unmasking electrical instability in the presence of coronary heart disease and in providing a simple technique for studying the effects of various interventions on the altered electrophysiologic properties of the ischemic heart.

Chinese hamster fibroblasts derived from seminiferous tubules grow well in Eagle's minimal essential medium containing glucose and 10% fetal calf serum. This medium contains no vitamin E; nevertheless, addition of the vitamin has no effect on the growth of these cells. When pyruvate is substituted for glucose as a carbon source, there is a great decrease in the growth rate which can be alleviated by d-α-tocopherol. The growth rate with pyruvate is much less than when no added carbon source is used.

This work was supported by U.S. Public Health Service Grant AM 14508 from the National Institute of Arthritis and Metabolic Diseases.

The effect of transplacental exposure of the fetal rat brain to the carcinogen ethylnitrosourea (ENU) on lysosomal acid hydrolase activities in glial cells has been reported. Primary monolayer cultures of brain cells derived from the brains of newborn rats exposed transplacentally to ENU and from unexposed newborn brains were used to provide concentrated samples of glial cells for hydrolase assay. The hydrolases assayed were β-glucuronidase, N-acetyl-β-D-glucosaminidase, arylsulfatase A and B and acid phosphatase and data were expressed as micromoles of substrate hydrolyzed per hour per milligram of protein. Experimental and control cultures were prepared, incubated and assayed contemporaneously and the ratios between treated and control hydrolase activities were used to evaluate the effect of transplacental ENU exposure.

Results showed that there was no effect on the activities of the lysosomal acid hydrolases measured in primary monolayer cultures of brain cells derived from newborn rat brains exposed transplacentally to ENU. Glucosaminidase activities increased through the 49 day incubation period, while maximum activities of β-glucuronidase, arylsulfatase and acid phosphatase were observed after 21 to 35 days incubation. Hydrolase activities in the brain cell cultures were markedly higher than activities previously reported in neonatal whole brain.

In vitro rat adipose tissue resting membrane potentials (RP) appear to be determined by Cl^- with K⁺ also playing a role. There are important similarities between adipose and hepatic tissue RP, and in vitro preparations of both appear to be “electrically” viable.

This study was assisted by U.S. Public Health Service Grant AM-06510-08, the General Research Fund of the University of Southern California School of Medicine, and the Professional Staff Association of the Los Angeles County-University of Southern California Medical Center.

5α-DHP administered 24 or 48 hr post-PMSG treatment to 30-day-old prepuberal rats stimulated ovulation, as indicated by a greater number of eggs in the oviducts at 72 hr and by a higher percentage of rats ovulating. 5α-DHP at 51 hr after gonadotropin stimulation caused inhibition of ovulation similar to the action of progesterone.

Supported by Grant No. M71.167 from the Population Council, New York. The authors thank Doctors Melvin L. Taymor and Robert K. Chipman for their interest in the study.

The sensitivity of the uterus is known to be regulated by estrogen and progesterone, but the nature of the involvement has not been clearly defined. It has been demonstrated in the rat that an inverse relationship exists between progesterone and uterine sialic acid (1) and that a direct relationship exists between estrogen and uterine sialic acid (1, 2). Preliminary work by author (unpublished data) and by Warren and Spicer (3) conflicts with the previous findings (1, 2). The membrane potentials of rat uterine cells were slightly increased with estrogen and greatly increased with progesterone (4). It has been postulated that rat uterine receptors for serotonin contains glycoproteins (5). The importance of glycoproteins in membrane structures has been neglected (6). Since sialic acid is an essential part of membrane glycoproteins and uterine sialic acid can be altered by the ovarian hormones, this experiment was conducted to determine the role glycoproteins might play in controlling the sensitivity of the uterus.

Materials and Methods. Charles River female rats weighing between 150-200 g were given 1 μg/kg of estradiol cypionate² 24 hr prior to the experiment. The rats were stunned by a blow on the head and one complete uterine horn was immediately removed. The uterine segment was placed in an isolated tissue bath³ at 30°. DeJalons (7) solution⁴ bubbled with 95% O₂ and 5% CO₂ was used to bathe the tissue.

Oxytocin⁵ was diluted from a stock concentration of 20 U/ml to a concentration of 0.2 U/ml. At the required time, increments of either 0.1 ml (0.02 U), 0.2 ml (0.04 U) or 0.3 ml (0.06 U) were diluted to 0.5 ml with DeJalons solution and injected into the tissue bath containing the uterine segment.

It has been reported that diethyl ether as well as other intravenous and inhalation anesthetics have varying depressant actions on neuromuscular transmission (1-3). With respect to diethyl ether this has been ascribed to a curare like action on the postjuctional membrane (4, 5). However, in recent years curare as well as other competitive neuromuscular blocking agents have been shown to have depressant action on the motor nerve terminal resulting in reduction of acetylcholine output (6, 7).

This work was conducted to elucidate the effects of some intravenous and inhalation anesthetics on acetylcholine output and thus gain a direct measure of activity on the nerve terminal. If they have a nerve terminal action, then they should reduce the amount of acetylcholine released upon nerve stimulation.

Methods. Frog sciatic nerve gastrocnemius muscle preparation. Frogs weighing between 20 and 25 g of the species Rana pipiens were stunned and decapitated. The skin was removed exposing the gastrocnemius muscle. The sciatic nerve was dissected free, ligated and cut. The gastrocnemius muscle was freed from the surrounding tissue and removed along with the sciatic nerve. The origin of the muscle was connected to a stationary metal rod while its tendon was attached to a transducer. The muscle was then placed in a 15 ml bath containing eserinized frog Ringer's solution (NaCl, 111.23; KCl, 1.88; NaH₂PO₄, 0.04; glucose, 11.10; NaHCO₃, 4.76; CaCl₂, 0.82; physostigmine 0.31 mmoles/liter) and bubbled with 100% O₂. The intravenous anesthetics were added directly to the bath. The inhalation agents were vaporized in a copper kettle and delivered to the bath mixed with 100% O₂. Interrupted supramaximal tetanic stimulation was applied to the nerve for 0.2 sec every 10 sec. The stimulation parameters were a frequency of 250 Hz, 1 msec duration and 5 V.

The rat is capable of synthesizing taurine from sulfate. The enzymatic pathway appears to be similar to that in chick liver which utilizes l-serine and activated sulfate (PAPS). The enzymes which catalyze this reaction sequence appear to be the same as those for the chick liver system, serine dehydrase, PAPS-sulfotransferase, and cysteic acid decarboxylase.

A comparative histochemical study of the endotoxin induced fibrinolytic activity in suspensions of leukocytes from man, baboon, dog and rabbit is reported. Apart from quantitative differences, leukocytes from the animal species behaved as human leukocytes. The number of fibrinolytic cells normally present increased following exposure to endotoxin and approached that of the neutrophils. Cell viability was not affected. Attention is drawn to certain critical aspects of methodology.

Treatment of male rats with monochlorhydrin (15 mg/kg administered orally for 9 days) caused an increased uptake of ⁶⁵Zn by the epididymis and vas deferens. In no other tissues examined was the ⁶⁵Zn uptake altered. The effect was most pronounced in corpus (92-126% increase in ⁶⁵Zn concn), with substantial increases also in cauda (44%) and vas deferens (29%), all statistically significant changes. Zinc is normally diminished as sperm traverse the epididymal pathway (16). The possibility is considered that these increased concentrations of zinc following monochlorhydrin treatment may be inhibitory, preventing sperm from attaining their final surge of motility in the oviducts requisite to penetration and fertilization of the ovum.

A degree of cross species susceptibility was observed on the effects of leukocytic endogenous mediator (LEM) on serum zinc depression and amino acid flux. LEM was shown to be protein in nature, and relatively stable under a wider range of pH and conditions of storage. Although LEM shares several chemical and physical characteristics with endogenous pyrogen (EP), some differences between the chemical properties and species specificity of these two mediators were noted.

Glucose-U-¹⁴C conversion into triglycerides (in the presence of insulin) decreased as rat fat cells enlarged (and/or aged). The results of this study show that the diminished lipogenic capacity results from the marked decrease in glyceride-fatty acid biosynthesis while glucose conversion into glyceride-glycerol was unaltered by fat cell size.

The authors thank Diane Dowd for her excellent technical assistance.

Administration of triundecanoin to young rats results in substantial enrichment of adipose tissue with undecanoate. This fatty acid is not synthesized de novo and does not recirculate in lipid ester form in significant quantity once it is released from adipose tissue. Incorporation of undecanoate into adipose tissue triglyceride proceeds linearly toward an asymptote and its disappearance follows in an exponential manner, thus providing a new model for the study of adipose tissue fatty acid kinetics.

Reticuloendothelial system phagocytosis was measured in man by the blood clearance of radioiodinated microaggregated human serum albumin. It was found to be substantially depressed following the ingestion of a palatable emulsion containing 8 oz of olive oil. The mechanism of this effect is unknown but the possibility of interference with phagocyte membrane function is suspected.

This work was supported by A Fight For Sight Grant-in-Aid No. 350 from the National Council to Combat Blindness, Inc., New York, NY. The authors are grateful to Dr. Baruj Benacerraf for his helpful suggestions on the manuscript and to Mr. Mortimer Schofield for his excellent technical assistance.

Drescher-photometric technique, which differentiates between inhibition of hemagglutination strain specific antibody from that caused by nonspecific inhibition or cross reacting antibodies, has been used in our laboratory to validate the specificity of antibody patterns found in human serum by conventional HI tests (1). On the basis of the age distribution of antibodies to prototype strains, the data have been interpreted to indicate that mankind has experienced in succession past periods of prevalence of swine, Hong Kong, Asian and Equine-2 like viruses, respectively, during the outbreaks of 1918-19, 1900 and 1889-90 and on at least 2 occasions during the period 1874-1888 (2–6).

At the time that these studies were being carried out, it had not been recognized that in special circumstances antibody mediated inhibition of hemagglutination could be effected solely by antineuraminidase antibodies presumably by causing steric hindrance with viral hemagglutinin (7). That finding raised the question whether the antibody patterns heretofore described might not be related to similarities of enzymes rather than to similarities of hemagglutinins present in the strains of former periods of prevalence. This alternate explanation seemed unlikely because in our experience HI titers of human serum caused by antineuraminidase antibodies were demonstratable only by use of erythrocytes of selected chickens or by addition of anti-human IgG to the reaction mixture, conditions that were not required for the demonstration of the antibody patterns (8). Moreover, the frequency and the height of titers observed at the peak of the antibody patterns were considerably greater than was found when measuring antineuraminidase antibody by HI under the best of conditions (12). However, to obtain direct evidence on the question whether the antibody patterns of human sera are oriented to viral hemagglutinin rather than to viral enzyme, a set of convalescent specimens were tested by Drescher's technique using a homologous natural virus and a recombinant containing the homologous hemagglutinin but a heterologous enzyme.

Rabbit and hamster surface terminal saccharides were quantitatively determined using ¹²⁵I-labeled plan agglutinins. Hamster spermatozoa specifically bound more concanavalin A, wheat germ agglutinin and Ricinus communis agglutinin molecules (1.9 × 10⁷, 0.55 × 10⁷, 3.3 × 10⁷, respectively) per spermatozoon than rabbit spermatozoa (1.0 × 10⁷, 0.22 × 10⁷, 1.2 × 10⁷, respectively). However, when corrected to sperm surface area, these differences were not significant.

Experimental allergic encephalomyelitis (EAE) produced during a transient period of mononuclear cell deficiency and relative neutrophilic leukocytosis induced by cyclophosphamide is characterized by neutrophilic rather than mononuclear cell infiltrates. Parabiosis to a normal animal increased the mononuclear content and inhibited the neutrophils in the infiltrates, presumably because the normal parabiont replenished the nonspecific mononuclear cells made deficient by cyclophosphamide. This evidence supports the hypothesis that neutrophilic infiltrates in EAE are caused by a deficiency of nonspecific mononuclear cells, and that mononuclear infiltrates in ordinary forms of EAE are reactive, nonspecific cells.

We are grateful for assistance from Dr. E. M. Hoenig, J. Torg, R. Zaplin, F. Strebel and Lillian Levine; for cyclophosphamide from Dr. W. A. Zygmunt of Mead Johnson & Co.; and for pertussis vaccine from Dr. H. B. Devlin of Parke, Davis & Co.

Bioassays of the pyrogenic activity of LP in the presence and absence of antipyretics were performed in cats. Sodium salicylate (0.50 and 1.00 mg) and acetaminophen (0.50 mg) given intraventricularly 30 min before iv injection of LP produced parallel shifts to the right of the log dose-response curve to LP. Such shifts are compatible with the hypothesis that these agents compete with LP for receptor sites within the central nervous system.

A continuous line of human breast carcinoma cells, HBT-3, was established in culture following collagenase treatment of a mucus producing adenocarcinoma. The cells are epithelioid in appearance, multiply rapidly, have a cloning efficiency of approximately 70%, and exhibit an abnormal karyotype with a mode of 66-69 chromosomes/cell and 3 markers.

Tumor material and pathological diagnosis were provided through the courtesy of Dr. J. D. Mashburn, Director of Laboratories, Washington Sanitarium and Hospital, Takoma Park, MD. Dr. C. S. Stulberg, Senior Research Associate, The Child Research Center of Michigan, Detroit, kindly performed the immunofluorescence cell typing tests.

A portion of these studies was carried out at Bionetics Research Laboratories, Inc., Bethesda, MD, under contract 69-2160 from the Special Virus Cancer Program of the National Cancer Institute. Technical assistance of Cathy K. Smith, Nancy Tuttle Fuller, and Diane Robertson is gratefully acknowledged. The authors thank Drs. Peter J. Fischinger and Tadao Aoki of the National Cancer Institute for their advice and many helpful discussions.

Cell walls from Listeria monocytogenes Strain A4413 underwent spontaneous dissolution between pH 8 and 5.2; the optimum was between pH 7 and 8. Walls from early log phase cells were degraded more rapidly than walls from terminal log phase cells. Dissolution could be precluded by mild heat treatment, and appeared related to the destruction of multiple layers of wall structure.

Four α-globulins were detected by starch gel electrophoresis in the serum of bovine fetuses of approximately 4 mo gestational age. These proteins were absent from the serum of their dams (α-fetospecific serum proteins) and disappeared sequentially with increasing fetal maturity beginning with the slowest migrating band.

We acknowledge the valuable technical assistance of R. M. Davis.

A soluble membrane antigen was isolated from vaginal, vulvar and cervical cancer which reacted with antiserum prepared in a guinea pig against semipurified herpesvirus type 2. In a series of coded experiments, 20 of 21 sera from women with cervical cancer reacted in complement-fixation tests with a soluble membrane antigen from genital cancer cells, while reactions occurred in 5 of 21 sera from matched control women. Neither cancer nor control sera reacted with similar preparations from normal vaginal tissue. Antibody to the virus-induced soluble membrane antigen of cancer tissues appears, therefore, to be more prevalent in the cancer population but is also found in a matched control population.

This research was supported in part by the Anna Fuller Fund to the George Washington University. Support was also provided by Research Contract PH 43-NCI-E-68-678 within the Special Virus-Cancer Program and Research Career Development Award 5-K3-A124,943 from the National Institute of Allergy and Infectious Diseases, National Institutes of Health. We are grateful to Dr. Frank Bepko, D. C. General Hospital and Dr. William Jaffurs, Columbia Hospital for some of the tissue specimens, and to K. Kennard, K. Tanner and L. Tapner for assistance.

The xanthine oxidase inhibitor allopurinol alone or in combination with hypoxanthine and adenine exerted little or no protection against the onset of irreversible shock. However when allopurinol is combined with the above two compounds in addition to inosine, alpha-ketoglutarate and oxalacetate 48 hr survival was increased to 43%. This may be due to prevention of loss of purine bases as well as supply of compounds to stimulate high-energy phosphate production. The effects may also be due to the vasodilator properties of the compounds increasing blood flow and thereby reducing the hypoxic effects.

The author acknowledges the technical assistance of Mrs. Hollie A. Moore. The author expresses his appreciation to Dr. Robert A. Maxwell, Department of Pharmacology, The Wellcome Research Laboratories, Burroughs-Wellcome and Co., Research Triangle Park, NC for the generous supply of sodium allopurinol and for many valuable discussions. Supported by The Wellcome Research Laboratories.

Experiments were designed to further characterize the nature of suckling mouse cataract agent (SMCA). The agent is sensitive to heat, trypsin and ultraviolet inactivation, but is stable over the pH range 5.8 to 10. Penicillin, kanamycin, streptomycin and rifampin have no effect on the replication of the agent while BUdR, actinomycin D and hydroxyurea are inhibitory. By filtration the size of the infectious particle was determined to be between 200 and 500 nm. Ultra-structural studies upon infected allantoic fluids reveal unique particles not present in fluids infected with a series of RNA and DNA viruses.

The response of the agent to drugs indicates that it is not a bacterial agent and is probably viral. Filtration experiments and ultrastructural studies favor a viral nature.

The authors acknowledge the expert technical assistance of Eva Nagy as electron microscopy technician and James E. Pounds who grew and titered the agent.

E. coli endotoxin exerts a direct vasoconstrictor effect on the coronary vessels. E. coli endotoxin also causes an initial increase in aortic blood flow, myocardial contractile force, and left ventricular work done. These initial cardiac responses can be attenuated by depleting catecholamines or by blocking beta-adrenergic receptor sites. The initial responses are somewhat modified by depletion of histamine indicating that catecholamines are not the sole mediators for the initial effects of endotoxin.

The author gratefully acknowledges the advice of Professor Shoji Saito (Nihon University School of Medicine, Department of Pharmacology, Tokyo, Japan) and the technical assistance of Mr. M. H. Hayman and Miss L. A. Anderson (both senior Medical Students at LSU Medical School in New Orleans). This study was partially supported by the Institutional Research Grant from Louisiana State University School of Medicine in New Orleans (No. 456-99-8602).

Persons living in malarious regions of Ethiopia had significantly higher serum concentrations of IgG and IgM but not of IgA than those Ethiopians who had never been exposed to malarious regions. Immunoglobulin concentrations of the latter group were quite comparable to those of normal controls from Houston. Splenomegaly in patients with malaria was associated with markedly increased concentrations of IgM in the serum.

The release of hyaluronidase by rabbit sperm was measured during in vitro incubation, in: (a) distilled water, (b) Tyrode's solution, and (c) rabbit uterine fluid. There was no apparent release of hyaluroni-dase in fluid obtained from the uterus of an estrus rabbit and collected prior to HCG-induced ovulation. In fluid obtained after HCG-induced ovulation, increases in hyaluronidase activity occurred, indicating hyaluronidase release by the sperm. The peak of maximum hyaluronidase activity was related to the timing of the fluid collection. In contrast, no discernible peak of hyaluroni-dase activity occurred when sperm were incubated in Tyrode's solution or in distilled water. Postovulatory uterine fluid appears to actively promote the release of hyaluronidase from sperm.

The release of hyaluronidase by rabbit sperm was measured, in vitro: (a) in uterine fluid from unilaterally ovariectomized rabbits, (b) in uterine fluid heated to 56°, (c) in postovulatory uterine fluid with added progesterone, and (d) in protein containing fractions of uterine fluid. Ovariectomy suppresses sperm hyaluronidase release as does heating of the uterine fluid or the increased availability of progesterone. The hyaluronidase releasing activity of uterine fluid is confined to one macromolecular fraction following gel filtration. The possible relationship of these results to the process of capacitation is discussed.

KC1 (40 mEq/liter) infused into the anterior descending branch of the left coronary artery of anesthetized dogs resulted in reproducible and reversible electrophysiologic evidence of systolic and diastolic injury currents accompanied by shortening of the Q-T interval in appropriate epicardial electrograms recorded by means of direct-coupled amplification. K⁺ infusion shortened the absolute and functional refractory periods in the experimental area, accompanied by a biphasic change in DT. Regional hyperkalemia produced both the electrocardiographic and electrophysiologic characteristics of acute myocardial ischemia and the results suggested that the altered distribution of extraellular K⁺ resulting from its release by ischemic myocardial cells could contribute importantly to the complex of “excitatory factors” related to the development of arrhythmias during acute myocardial infarction.

Mice which have been immunized against the isoantigens of allogenic bone marrow cells reject bone marrow cells from donors of the allogeneic strain that are injected after the administration of a lethal dose of whole-body X irradiation. Repopulation of the damaged hematopoietic tissues is therefore prevented. It has now been demonstrated that treatment with anti-lymphocyte serum or normal rabbit serum abrogates such immunity, as allogeneic bone marrow cells repopulate the medullary cavity of the femur in sensitized recipients treated with anti-lymphocyte serum or normal rabbit serum before being exposed to a lethal dose of whole-body X irradiation.

We are indebted to Mrs. V. Littlewood, Mrs. C. V. Briscoe, Mr. D. J. F. Steers and Mr. M. Ho for technical assistance and to Miss A. L. Harris for typing the manuscript.

Glutamic-oxalacetic and lactic dehydrogenase activity associated with human beta-lipoprotein can be increased by exposure to sonic radiation. Maximum activity is reached earliest in solutions having a low salt concentration and an acidic pH. The increase in activity occurs concomitantly with an increase in hydrogen ion concentration and specific viscosity. Disruption of the lipoprotein molecule is evidenced by increased viscosity, increased turbidity, and decreased immunologic reactivity toward a specific antiserum. Enzymic activity found in beta-lipoprotein isolated by using two radically different techniques gave equivalent results when exposed to radiation. This strongly mitigates against the possibility of an isolation artifact.

African green-monkey kidney cell clones partially resistant to SV40 have been isolated in viral-specific anti-serum from chronically infected cultures. These clones were virus-free and produced no T antigen. One clone was found to be partially resistant to infection with SV40 virions but susceptible to infection by SV40 DNA. Chronically infected cultures were cured of infection by treatment with SV40 anti-serum while maintaining their partial resistance to SV40.

This investigation was supported by Public Health Service Research grant AI-01992, a Damon Runyon postdoctoral fellowship (DRF-466), and by the Denver M. Eckert Special Grant for Cancer Research from the American Cancer Society (Grant E-612).

The authors gratefully acknowledge the encouragement and advice of Dr. William S. Reznikoff.