Experimental Biology and Medicine

A method for the kinetic analysis of the formation and disappearance of intermediates in immune hemolysis has been described. The interpretation of results obtained with it has been discussed, and certain applications indicated.

Placental transfer of radioactive Vit. B₁₂ in the dog following pregestational administration, was found in the entire litter to be 20% of the residual radioactive vitamin in the bitch at time of delivery. Because the proportional distribution of radioactive B₁₂ among major organs of the mother and pups was found to be similar, it was possible to calculate placental transfer from this characteristic as well as by postpartum “calibration” of the hepatic radioactivity in pups. Biological half-life of the radioactive Vit. B₁₂ averaged 2 months in pups and bitch during postpartum period. A new explanation is suggested for the low maternal and high fetal plasma levels of Vit. B₁₂.

A method is described for determination of serum total and organic bound phosphorus using chloric acid digestion and subsequent formation and reduction of a phosphomolybdate complex with p-semidine. The advantages of the method are ease of digestion and color development and stability of color-complex. This method compares well with the Fiske-Subbarow method.

No difference in susceptibility to infection by a highly virulent strain of pneumococci could be demonstrated between normal and splenectomized suckling rats. The implications of this finding are briefly discussed.

Four lysine analogs were studied for antimetabolic action against radioactive lysine incorporation into rat bone marrow protein in vitro. S-(β-Aminoethyl)-cysteine was a potent competitive inhibitor and ∊-C-methyl lysine was moderately active. δ-Hydroxylysine inhibited slightly and in a non-competitive manner. Hexahomoserine was inactive.

1. A method for evaluating erythropoietic stimulation has been described. 2. Following a standard hemorrhage there is a 2- to 5-fold increase in P³² uptake by splenic DNA. 3. Exposure to anoxic anoxia increases P³² uptake by the DNA of spleen. 4. Injection of anemic rabbit or hypoxic rabbit plasma increased P³² uptake by splenic DNA in normal receptor rats.

1. Incubation of freshly prepared human platelets with a variety of sulfhydryl inhibitors results in increased rate of platelet breakdown. 2. In all cases studied the effects of inhibitors can be decreased in extent by suitable concentrations of SH-containing substances such as cysteine or reduced glutathione. 3. Results obtained suggest a direct relationship between platelet sulfhydryl groups and platelet structure. The possible link of this relationship to platelet metabolism is briefly discussed.

A cytopathogenic effect has been observed in cultures of murine malignant lymphoma cells (strain P388 D₁) inoculated with polyoma virus. There is evidence of viral multiplication in these cell cultures and the virus retains its ability to produce tumors when inoculated into newborn hamsters. The virus-host cell system of polyoma virus and milk-adapted P388 D₁ cells seems to be a suitable one for studies of this oncogenic agent.

Different fractions of serum proteins were determined by paper electrophoresis in folic acid deficient and pair-fed normal rats. Total serum protein was low and plasma fibrinogen was significantly high in the deficient animals. There was a significant decrease in albumin and γ-globulin, considerable increase in α₂-globulin, with no significant change in α₁ and β-globulin fractions in the serum of folic acid deficient rats.

Mature and immature rats were injected with radioacitve magnesium and distribution of the isotope in various tissues was measured. The exchange with plasma magnesium was rapid and complete within 3 hours in liver, kidney, and heart muscle. In brain, testes, erythrocytes and skeletal muscle there was a rapidly exchanging component similar to that in liver, etc., but more than half the magnesium exchanged very slowly. The similarity between functionally disparate tissues in each of the 2 groups suggests that the magnesium is present in 2 or more physiologic states. In one state the turnover time is 1.2 hours and in the other it is 25 hours. The exchange was faster in muscles which were stimulated to contract repeatedly than in resting muscles. In immature rats uptake of radioactive magnesium by the testes was slightly faster than in the mature animals and net decay of plasma activity was faster but there were no other significant differences.

1) The polarographic method for measuring changes in O₂ concentration has been employed for assessing ability of salicylates and related compounds to uncouple phosphorylation. The extent of stimulation of respiration caused by addition of these compounds to rat heart mitochondria oxidizing alpha-ketoglutarate in a phosphate-acceptor deficient system was used as a criterion of uncoupling action. 2) Thiosalicylate was many times more active than salicylate and other salicy late-derivatives tested. Some chemical and physical properties possibly responsible for the uncoupling action of salicylate and certain of its congeners were considered. The in vitro action of salicylates was discussed in relation to their anti-rheumatic activity and cardiovascular effects.

Rabbits fed ad lib. on a high cholesterol diet were exercised 8 hours daily for 2 months. This regimen did not inhibit atherogenesis as measured by serum and aortic tissue cholesterol levels.

These data suggest the following tentative conclusions: 1. Adrenal 17-hydroxycorticoids appear to exert an effect on utilization of acetate and to decrease oxidation of this 2 carbon fragment to CO₂. 2. Tn the human as in tissues of lower animals and in plant seeds, carboxyl carbon of acetate is more readily oxidized than is methyl carbon. The finding of a decrease in lipid synthesis form methyl labeled acetate in association with a decrease in oxidation of this compound as compared to carboxyl labeled acetate suggests that the carboxyl carbon may also be used preferentially for lipid synthesis in the human. 3. The syndrome of lipoatrophic diabetes appears to be associated with a decreased ability to store and perhaps to synthesize lipids in the adipose tissue rather than an increase in utilization of lipids of adipose tissue. 4. The stable adult diabetic may have a defect in conversion of 2 carbon fragments to fatty acids, even when the fasting blood sugar is normal.

Chicks were fed purified diets containing 3% cholesterol and either casein, gelatin and sucrose or soybean protein and glucose together with vitamins and minerals. The chicks receiving casein, gelatin and sucrose had higher plasma cholesterol values than did those whose diet contained soy protein and glucose. When both diets contained casein and gelatin, those chicks on the diet containing sucrose as sole carbohydrate source had higher plasma cholesterol values than did those on a diet containing glucose; when these same diets were fed without the addition of 3% cholesterol, no significant difference in plasma cholesterol concentrations was found. Serum cholesterol values of rabbits fed a cholesterol diet containing sucrose were higher than those from a group on a similar diet containing glucose.

To detect changes with age in structure of myocardial proteins, swelling properties of human myocardium in solutions of HCl and NaOH were investigated. Fragments of myocardium were incubated in solutions of various pH values and increases in weight were used as measures of swelling ability. Maximal swelling occurred at pH 0.9, 2.4 and 11.2. Greatest swelling, probably of the Donnan equilibrium type, occurred at pH 11.2 and this value was used for subsequent studies. Swelling decreases rapidly in the first years of life, then appears to remain constant until 35 years of age after which it decreases, to apparently remain constant at a low level. Collagen content, dry weight and amount of solids extracted during swelling do not vary with age. Heating myocardium causes a decrease in swelling ability. The possible role of thermal denaturation in myocardial aging and physiological implications of swelling changes are discussed.

The life span of red cells of 5 newborns at high altitudes and 5 newborns at sea level was determined by “tagging” the cells with Cr⁵¹ and subsequently injecting them into healthy adults. Survival time of red cells in newborns is shorter than that observed in adult subjects. There was no appreciable difference in results obtained in newborns at sea level and at high altitudes.

In the dog pyridoxine is ineffective in either increasing rate of metabolism of alcohol or reducing degree of intoxication at a given blood alcohol concentration. This is confirmatory of previous work in man, and is conclusive evidence of the uselessness of pyridoxine as an antagonist of alcoholic intoxication.

Rabbits were immunized with rat fibrin and the resulting antisera clotted with normal rat plasma. From the clot a substance was isolated and labeled with I¹³¹ that showed a strong tendency to bind to rat fibrin clots formed in its presence. This substance, presumably an antibody to rat fibrin, when injected intravenously into rats bearing the transplantable Murphy-Sturm lymphosarcoma localized with a high degree of preferentiality in this tumor.

1) Plasma from heparin-injected hepatectomized, CCl₄-cirrhotic and nephrectomized rats exhibited significantly greater lipemia clearing activity than that of heparin-injected normal control animals, when incubated with lipemic plasma in vitro. 2) These results represent indirect evidence for the presence of a clearing factor inactivating system in liver and kidney.

It is shown that blocking the RE system with India ink diminishes or abolishes capillary resistance response to cortisone and STH. That large doses of cortisone can overcome the block suggests that the RE system functions by increasing sensitivity of tissues to cortisone.

Leucine-vasopressin (phenylalanine-analogue of oxytocin) injected i.v. in sub-maximal antidiuretic doses to hydrated dogs and rats produced an increase in rate of urinary excretion of both sodium and potassium.

Beagle metabolism of short-lived Pb²¹² has been studied following intravenous injection, and after transfusion of blood cells tagged with Pb²¹² in vitro. The latter proved to be a satisfactory method to determine blood volume. When Pb²¹² was given intravenously, in vivo tagging of blood cells occurred. A maximum of 65% of the activity in cells was reached at 2 to 3 hours after injection, then Pb²¹² in blood cells decreased with a biological t_1/2 = 37 hours and an effective t_1/2 = 8.2 hours. The same decrease occurred after injection of in vitro tagged cells. In both experiments essentially all Pb²¹² decayed inside the dog. Half decayed in blood in the in vivo tagging experiment: 4′5 decayed in blood when tagging was done in vitro.

Asian strain virus was demonstrated in extrapulmonary tissues from 3 influenza-associated deaths. This finding suggests the occurrence of viremia in overwhelming influenza in man.

Seitz filtration of poliomyelitis vaccine pools during formaldehyde-inactivation process was found to lower their immunogenic activity. Monovalent vaccine pools in which filtration through Seitz filter pads during inactivation process was either omitted or replaced by filtration through fritted glass filters, proved to be of high antigenicity both in guinea pigs and in triply negative children. Routine safety tests in tissue culture carried out on such pools were consistently negative. Additional proof of the safety of such pools was provided by absence of live poliovirus from large samples withdrawn as much as 5 days prior to end of inactivation period, and also by use of these vaccines in the field.

(1) Ability of 4 acidic polymers to inhibit lysozyme and or pepsin has been measured. (2) Their anti-enzyme effect is compared to their action in the Shay rat.

Investigation of the force-velocity relationship of muscles actively shortened by tetanus toxin injection reveals that these preparations exhibit a significant decline in the a constant of Hill's characteristic equation. An attempt has been made to interpret the above change in terms of other reported mechanical and chemical changes.

Oleic-1-C¹⁴ acid and a mixture of this acid with cholesterol were administered to rats with lymph cannulae. Chromatographic separation of lymph lipids in both cases revealed that the effect of cholesterol was to decrease the proportion of triglyceride and increase those of sterol ester and phospholipid. Chromatographic separation of fatty acids of lipids from the latter case revealed that although glyceride fatty acid distribution was similar to that of fed acids, both the sterol ester and phospholipid fatty acids were diluted with endogenous oleic, linoleic and stearic acids.

1) The fact that potentiation of the action of epinephrine after small doses of endotoxin was observed only to a slight extent in the presence of barbiturate, and not at all when ether or decapitation without anesthesia was employed to prepare the ear for perfusion, leads us to question whether the effect described by Zweifach, Nagler and Thomas is actually a direct potentiating action of epinephrine. We have no explanation as to how endotoxin might antagonize a barbiturate effect. 2) One point is noteworthy, our preparations in general had a much lower control epinephrine threshold than those reported for the perfused rabbit ear by above mentioned workers. 3) Our results are entirely uniform in showing that no reversal of epinephrine action after the large doses of endotoxin occurred, even with barbiturate anesthesia. We have no explanation to offer for this failure to confirm Zweifach et al.

An acute lethal effect from electroshock convulsions has been demonstrated to occur among mice of the DBA, CFW and C57 strains, and to a lesser extent the ICR strains. CF#1 mice were rarely susceptible. Death was ascribed to failure to resume breathing and appeared to be dependent upon occurrence of maximal seizure and independent of intensity of current employed to elicit the seizure. The mechanisms involved were not revealed, but attention was directed to the finding that strains susceptible to post-seizure electroshock death are identical to those which are susceptible to audiogenic seizures.

Three groups of normal rabbits were starved for 17 to 48 hours prior to feeding of a dilute solution of MgSO₄. Mean urinary excretion of radioactivity in 48 hours in the 3 groups ranged between 10 and 12.5%. The high concentration of radioactivity detected in the midabdomen by external survey was traced to fecal content of caecum and colon. Fecal excretion was increased by resumption of feeding after exhibition of Mg²⁸, and concentration of radioactivity over the midabdomen decreased. These results suggest that poor gastrointestinal absorption of magnesium accounts for its low renal excretion. Absorption does not appear to occur from the large intestine.

A method of bioassay for small amounts of antidiuretic hormone in plasma of a dog is presented. The method utilizes rats rendered unconscious with ethanol, under constant water load, and with intravenous injections of all standards and unknowns. Change in specific gravity of rat urine expressed as antidiuretic index is used as criterion of potency. This method appears to be the most sensitive bioassay for ADH available in that small dose changes of reference vasopressin, or endogenous circulating ADH, can be differentiated.

1. It has been demonstrated that iron is extracted from horse spleen hemosiderin at different rates by disodium ethylenediamine tetraacetate. During the first 24 hours of extraction, between 21 and 70% of total hemosiderin iron was removed by chelating agent from 8 hemosiderin preparations which contained between 33.5 and 19% iron, respectively. The amount of iron removed is inversely proportional to total hemosiderin iron concentration. Subsequently, iron is dissolved at a slow rate until practically all is removed during 25 days extraction. 2. Analytical data for amount of ferritin present in hemosiderin are presented.

Studies made with 3 strains of chicks showed one strain to be significantly different in retention of mercury in liver and kidneys, following intramuscular injections of phenylmercury acetate or mercuric chloride. Differences following injection of equivalent amounts of mercury as ethylmercury chloride or Salyrgan were much less. Mercury retention was greater in the strain selected for resistance to lymphomatosis than in the 2 susceptible strains which showed little difference.

Amiphenazole was effective in antagonizing morphine depression in dogs; bromosulfolane was less effective even at toxic doses. Amiphenazole did not significantly alter the analgetic effect of morphine in mice, though this compound alone produced a mild but transient analgetic effect.

The results with the agar precipitation technic indicated the existence of multiple antigenic constituents of human plasmin, possibly due to contamination by other components of plasma. Our preparations of human plasmin. however, either contained no streptokinase or amounts of this agent insufficient to induce an antigenic response. Streptokinase represents a possible contaminant or constituent of plasmin. Thus, at least in our experimental condition, negative results are important as they eliminate one possible source of iso-antigenicity of human plasmin.

Summary. Agar precipitation technic detected no antibodies against purified streptokinase in rabbits immunized with streptokinase-activated, purified human plasmin.

1. The effects of several surface-active agents on carbohydrate metabolism have been studied. Fermentation, oxygen consumption, and the Pasteur Effect are affected by these agents. 2. With the exception that oxygen consumption is affected differently by various surfactants tested, all 4 agents show qualitative similarities in their effects on carbohydrate metabolism. Benzalkonium chloride showed greatest effect on aerobic CO₂ production and the Pasteur Effect. 3. Several hexoses used as substrates showed the effect of benzalkonium ion to be non-specific in its action on metabolism of 3 hexose substrates. 4. Effects of the agents on oxygen consumption and effects of pH were discussed.

Kethoxal (β-ethoxy-α-ketobutyraldehyde hydrate) reacted chemically with a variety of normal metabolites. Some of these reactions (e.g., those with cysteine and arginine) resulted in rapid loss of antiviral activity; others (e.g., with glycine and intact gelatin) in a more gradual loss of activity, while still others, particularly with serine and threonine, gave products possessing apparently undiminished activity. It was concluded that lack of significant antiviral activity by Kethoxal in animals could be attributed principally to its rapid binding and inactivation by proteins, amino acids and other metabolites.

Susceptibility of hamster kidney tissue culture to enteroviruses was studied. A cytopathogenic effect was obtained with the prototype Coxsackie viruses (A9, B1–B5) and prototype ECHO virus types 9 and 10. Variability of infectivity was shown for ECHO 9 isolates, only 2 of 27 positive. Other ECHO serotypes and polioviruses were negative. Strains of herpes simplex, vaccinia, Newcastle disease virus and influenza (Asian), also produced a cytopathogenic effect in hamster kidneys. Use of hamster kidney tissue cultures as a selective system in identification of agents from cases of aseptic meningitis was reported.

Osborne-Mendel rats fed p-dimethylaminobenzene − 1-azo − 1-naphthalene (DAN) and p-dimethylaminoazobenzene (DAB) showed a higher incidence of liver tumors in males than in females. In DAN fed rats the respective incidence was 75 and 17% and in DAB fed rats 85 and 19%. Feeding higher doses of DAN (0.3%) to rats, failed to shorten the induction period for this compound. Rats fed p-dimethylaminobenzene-1-azo-2-naphthalene (DA-2-N) showed no significant difference in incidence of liver tumors between males (98%) and females (100%). However, tumors were much slower in appearing in females than in males, indicating relative resistance of the female liver to carcinogenesis induced by DA-2-N.

Rate of endogenous respiration of human gingival tissue is markedly dependent upon time. However, reasonably high values may be obtained for endogenous QO₂ if speed and low temperatures are used in preparation of the slices. Respiratory studies on gingiva should be carried out in the presence of added substrate.

1. Of 39 young and adult C3H mice, thymectomized, and a few days later inoculated intraperitoneally with passage A leukemic filtrate, none developed leukemia. Of 41 normal controls inoculated simultaneously with the same filtrate 18 (44%), developed leukemia at 7 months average age. 2. Of 55 suckling C3H mice inoculated with passage A leukemic filtrate when less than 9 days old, then 1 month later thymectomized, only 1 thus far developed a palpable spleen, and definite leukemia. Of 78 control litter mates inoculated simultaneously with the same filtrates, but not thymectomized, 68 (87%), developed leukemia at 2.7 months average age. 3. Thymectomy, either preceding, or following inoculation of leukemic passage A filtrate, inhibits development of leukemia in otherwise susceptible C3H mice.

A non-lethal, haptenic polysaccharide from K. pneumoniae, given intravenously to guinea pigs, produces a marked, but transient, elevation in plasma 17-hydroxycorticosteroids. Incubation of the polysaccharide with normal guinea pig plasma partially inactivates this response. The polysaccharide remaining in the circulating plasma 6 and 12 hours after intravenous injection shows a greater loss of this ACTH releasing property. Electrophoretic studies indicate that the polysaccharide is bound to plasma proteins, but there are marked differences in in vitro and in vivo binding with albumin. The bound polysaccharide, however, retains its haptenic qualities. These findings suggest that the bacterial polysaccharide undergoes little, if any, degradation but loses its 17-OHCS evoking capacity by combining with plasma proteins.

Thirty-one dogs were cooled down to 80°F and the ability of various pharmacologic agents to facilitate hypothermia induction was observed. 1) Chlorpromazine and the “lytic cocktail” accelerate hypothermia induction time. 2) Chlorpromazine is apparently the only effective agent in the “lytic cocktail.” 3) Chlorpromazine accelerates hypothermia induction by a central action. 4) Pentobarbital anesthesia is essential for production of the chlorpromazine effect.

Vit. B₁₂ deficiency in the dam resulted in newborn rats with anemia, leukopenia and granulocytopenia. The liver showed a marked reduction in hemopoietic elements, vascular blocks, and an accumulation of lipide in the hepatic cells. The femur of Vit. B₁₂ deficient rat showed abnormal patterns of growth and bone marrow contained increased concentration of hemopoietic elements. However, most cells appeared unable to complete maturation.

D-glucuronolactone-6-C¹⁴ was administered to actively growing rats to study its incorporation into connective tissue acid polysaccharides. The same compound was administered to guinea pigs after injection of carrageenin which stimulates formation of new connective tissue. No significant incorporation of glucuronolactone into the APS fraction of connective tissues was found.

1) Data were obtained in mice on translocation of 5 radioactive silver Ag¹¹¹ compounds at various intervals after injection into the tail by a previously described method of serial tail amputations and 24 hours after injection into the scalp. 2) Ag¹¹¹ nitrate storage rate at site of injection was higher than for another soluble compound—Ag¹¹¹ lactate, but lower than for 2 insoluble coarsely particulate compounds—Ag¹¹¹ oxide and chloride; on the contrary, pick-up by liver and blood was highest for soluble compounds. 3) Translocation of each compound from the scalp followed the pattern of its translocation from the tail but at a much slower rate. 4) In the above experimental conditions the fate of various Ag¹¹¹ compounds in the body of the mouse depended mainly a) on the physico-chemical properties of the compound (solubility, pH, ability to form colloidal complexes with tissue fluid and blood, size and tendency of insoluble particles to clump) and b) on biological conditions at site of injection. 5) The planned use of this method in tumor-bearing mice is presumed to be helpful for selection of the choice compound for local or systemic therapeutic application.

Furazolidone in adequate dosage exerts a significant hypotensive action. The exact mechanism whereby this occurs remains obscure. Frequency and severity of adverse effects and development of a refractory state limit application of the drug in treatment of patients with hypertension. It is to be hoped that derivatives may dissociate the hypotensive from the unwanted effects.

Pretreatment with dibenamine and pyrilamine, dibenamine alone, or LSD with or without pyrilamine was found to diminish or prevent the acute hypotensive response of the cat to small doses of endotoxin.

1. A microbiological assay procedure giving presumptive evidence for presence of formiminoglutamic acid (FIGLU) was carried out on urine specimens from normal individuals, children with acute leukemia receiving various types of chemotherapy, and a patient with macrocytic anemia of pregnancy. The data indicated strongly that FIGLU was being excreted in children with acute leukemia receiving 4-aminofolic acid antagonists and in macrocytic anemia of pregnancy. 2. A highly purified mercury salt of a glutamic acid precursor was isolated from urine of patient with leukemia during amethopterin therapy, and on the basis of its chemical and microbiological properties, concluded to be FIGLU. 3. It is postulated that folic acid antagonists induced a folic acid deficiency, resulting in insufficient tetrahydrofolic acid needed for catabolism of FIGLU. Consequently FIGLU accumulated. It is suggested that determination of FIGLU in human urine may be a useful aid in diagnosing folic acid deficiency in man.

Rats exposed to low ambient temperatures were trained to depress a response bar to obtain heat. The heat remained on as long as the bar was depressed. Total time of bar depression was shown to be a function of hours of food deprivation.

H. capsulatum strain G17 (M) polysaccharide was capable of producing active resistance against intravenously induced histoplasmosis in mice. However, mice immunized with a H. capsulatum whole yeast cell antigen showed greater resistance when the H. capsulatum polysaccharide immunized, whole cell immunized and nonimmunized control mice were challenged by the intravenous injection of known numbers of viable H. capsulatum yeast phase organism.

1. A method is described for determination of carboxypeptidase in human pancreatic juice. Eighteen samples of pancreatic juice gave an average value for active carboxypeptidase of 3.9 mg % with a range of 2.2–6.2 mg %. Total enzyme concentration representing active enzyme plus procarboxypeptidase gave an average value of 52.8 mg % with a range of 28.3–134.0 mg %. 2. A significant amount of active carboxypeptidase was found in fresh pancreatic juice. High values of active and total carboxypeptidase were found initially postoperatively but these declined on about the third postoperative day. 3. Carboxypeptidase was found to be more stable to autolysis than trypsin.

1) Metachromatic sulfuric acid esters (SAE) were measured in sulfatide fractions extracted from normal and abnormal white matter and kidney. 2) Slightly lower than average SAE values for white matter were found in early childhood, in old age, and in diseases interfering with myelin metabolism. 3) The average SAE value in normal mature white matter was 58 mg/g. This was 10 times the value for normal kidney and corresponds with the much greater lipid metachromasia in white matter histologically. 4) Statistically significant elevations in sulfatide values were found in white matter and kidney in one disease (metachromatic leucoencephalopathy). 5) This accumulation may be related to an error in sulfatide metabolism, and appears, descriptively, to constitute a “sulfatide lipidosis.”

1. An in vivo method has been described for studying radiophosphorus and radiostrontium absorption from the intestinal tract in rats. The method is simple, avoids surgical trauma and permits visualization of the absorption process in individual animals. Rate of absorption at various times may also be estimated. This is not possible with the standard balance studies. Anesthesia is not necessary, though no difference of Sr⁸⁹ absorption was found when anesthesia was used. 2. Absorption of radiophosphorus was very rapid, reaching a peak at 30 minutes. In most animals, there was a delay of 20–30 minutes before significant amounts of radiostrontium were absorbed, and the whole process was slower. 3. It was possible to measure radiostrontium absorption on two different occasions in the same animal, first with Sr⁸⁹ and then with Sr⁸⁵. This should prove of value in studying factors affecting strontium absorption.

For routine serological diagnosis of influenza, the CF test is preferable to HI test. A/Asian influenza virus was more readily isolated in the embryonate egg than in monkey kidney cell tissue culture.

Growth of psittacosis virus (6BC) in L cells in vitro was inhibited by sulfadiazine and this inhibition was reversed by addtion of PABA. L cell tissue cultures infected with the virus contained 2 or more times the amount of folic acid in noninfected cultures. The possibility of introduction into the cell or induction in the cell by the virus of enzyme or enzyme system, making the infected cell capable of folic acid synthesis, is discussed.

Bovine serum protein was fractionated with a continuous flow electrophoresis apparatus. Vit. A and carotene were principally associated with albumin. When one co-twin of identical twin heifers was subjected to Vit. A deficiency, serum albumin was progressively reduced. Following an intravenous injection of carotene, the deficient heifer low in serum albumin retained approximately one-half the plasma-carotene concentration as her normal co-twin. Serum albumin returned to normal in the deficient co-twin within 10 days following intravenous Vit. A administration.

The plasma corticosteroid content of the guinea pig offers a suitable means for evaluating the potency of adrenocorticotrophic hormone, and also the menstrua which may be useful in extending the physiological or pharmacological effect of this hormone.

Summary. The response of the guinea pig to exogenous adrenocorticotrophin was determined using plasma steroid concentration as criteria of response. Average steroid concentration for 50 untreated male guinea pigs was 43 ± 1.7. A graded response was obtained after corticotrophin administration which when plotted yielded a straight line with a slope adequate to determine differences between a 1 1/2 to 3-fold increment in dose. Comparison of corticotrophin administered subcutaneously in a gelatin menstruum with that administered in water showed a 2–3 time greater activity when gelatin is employed as a menstruum than when the hormone is dissolved in water. This is in accord with findings in the rat using the adrenal ascorbic acid depletion as a measure of activity, and clinically in the human. Small amounts of glucuronide conjugated corticoids were also found in the plasma.

Various concepts of the function of renal lymph have been evolved, based largely on indirect evidence(1). The present report deals chiefly with electrolyte concentrations in renal lymph, preliminary data from a study designed to obtain more direct and definitive evidence of its function.

Procedure. Healthy mongrel dogs of both sexes were anesthetized with sodium pentobarbital (25 mg/kg). A polyethylene catheter was inserted into jugular vein via 15 gauge needle and utilized for plasma sampling and administration of fluids and drugs. The thoracic duct was cannulated and thoracic duct lymph collected in most experiments. Both ureters were catheterized at their junction with the bladder and urine collected separately from each kidney. Femoral arterial pressure was recorded with a mercury manometer. A left flank incision was employed to expose the kidney. The fat at both poles was usually ligated to engorge the capsular lymphatics and permit their cannulation with #50 polyethylene tubing. Renal lymph was collected in small glass tubes capped with one-hole stoppers to prevent evaporation and volumes estimated to the nearest .05 ml. During the prolonged period of exposure the kidney was covered with saran wrap to prevent evaporation. Sodium and potassium were analyzed with a Baird flamephotometer using internal standards, and chlorides by the method of Schales and Schales(2). Serum, renal lymph, and thoracic duct lymph proteins were analyzed with a Spinco paper electrophoresis apparatus while total protein was determined by the falling drop method(3). Heparin prevented clotting in blood and thoracic duct lymph samples.

Results. Concentrations of Na, Cl, and K in plasma, thoracic duct lymph and renal lymph are given in Table I. Na concentrations of plasma and thoracic duct lymph are similar (averages = 145.7 ± .77 and 145.6 ± 2.6 meq/l. Renal lymph, however, has an average concentration of 162.1 ± 2.8 meq/l, 11.3% higher than the average plasma value, a difference which is significant (P value = <.001).

Bioassay of uteri of pregnant rats reveal a significant reduction of concentration and content of histamine during 24 hr prior to actual implantation of blastocyst.

A method based upon potentiation of a subhypnotic dose of hexobarbital has been employed to detect depressant activity of drugs. It is rapid, and gives reproducible results with known CNS depressants. It appears to differentiate depressant drugs from those which prolong the action of a hypnotic dose of hexobarbital by interference with biotransformation mechanisms. It affords a rapid means of detecting depressant activity of drugs not ordinarily classified as central depressants.

Growth characteristics of a canine Sertoli cell adenocarcinoma in tissue culture are described. Histopathological and cytological picture of the original tumor, of cells grown in tissue culture and material removed from dogs inoculated with tissue culture cells are shown. According to histopathological criteria, the original tumor, tissue culture cells and material removed from dogs inoculated with 10th passage SCT cells are all malignant. The viral spectrum of this cell line is presented.

Mice were subjected to continuous gamma radiation (128 r/22 hours) for 3 weeks, and bactericidal activity of their phagocytes determined at weekly intervals. Bactericidal activity declined gradually through 2 weeks exposure (1800 r) then fell off rapidly in the third week (2695 r). These results are compared to those obtained with mice exposed to single doses of x-irradiation.

1) A hypotensive, smooth muscle-contracting principle has been identified in the placenta of the rabbit and of several other species. It is dialysable, stable to heat at neutral pH for 3 minutes at 100°C, and unstable in alkali and acid. It has been separated chromatographically and by use of inhibitors from acetyl choline, serotonin, and histamine. The active principle is hydrolysable with liberation of free amino acids and with resulting loss of activity on guinea pig ileum and blood pressure. It has been tentatively identified as a polypeptide. 2) On intravenous injection the active principle causes a fall in blood pressure, cardiac dilatation, intestinal and uterine peristalsis, and death from respiratory failure. It is found predominantly in the fetal part of the placenta and at all stages of pregnancy in the rabbit from 16th day to term.

1. Addition to blood of 100 μg/ml of hydrocortisone or of 0.1 to 10 g/ml of prochlorperazine results in inhibition of leucocyte migration. Addition of both compounds together results in less inhibition than is obtained with either compound alone. 2. Reserpine at concentrations of 0.1 μg/ml to 100 μg/ml is less inhibiting to leucocyte migration than is prochlorperazine. Addition of both reserpine and hydrocortisone to blood results in less inhibition to leucocyte migration than when hydrocortisone alone is added. 3. Thorazine at concentrations of 0.001 μg/ml to 1 μg/ml is inhibitory to leucocyte migration. Addition of both thorazine and hydrocortisone to blood, results in less inhibition to leucocyte migration than when hydrocortisone alone is added.

Lethally irradiated mice that received blood-forming cells from homologous fetal liver showed better long-term survival and lymphatic tissue recovery, than those treated with blood-forming cells from adult homologous bone marrow. In both cases there was transplantation and persistence of erythropoietic cells.

Submaxillary glands of hypophysectomized male albino rats injected with growth hormone and thyroxine, both alone and in combination, were studied histologically and enzymatically. Growth hormone and thyroxine separately were only partially effective in preventing hypophysectomy-induced enzymatic and histologic changes in the submaxillary salivary gland. The 2 hormones when administerd together, however, maintained normal histologic and enzymatic activity. These results are comparable to those previously reported utilizing testosterone and thyroxine in combination. Apparently the stimulatory action of thyroxine upon the submaxillary gland function may be enhanced by simultaneous administration of either testosterone or growth hormone, both of which are deficient in the hypophysectomized animal.

Six strains of E. histolytica were shown to hydrolyze gelatin. The gelatinase was inactivated by heat, copper salts, and freezing. The effects of concentration of enzyme and pH were studied.

Exposure to 400 r of whole-body X-radiation resulted in 100% mortality in 10 to 15 days of young male guinea pigs fed a basal diet of bran and oats plus ascorbic acid. Supplementation with cabbage or broccoli for 2 weeks before irradiation and during 30 days after irradiation significantly reduced mortalty. Lyophilized cabbage retained ability to reduce radiation mortality. Pre-feeding of guinea pigs to time of radiation exposure, signficantly delayed onset of death and enabled some animals to survive test period. Post-irradiation supplementation with cabbage also yielded a lower total mortality. Feeding of cabbage both before and after radiation exposure produced greatest amount of protection.

1) Adult human and rabbit Fallopian tube fragments, which maintained in in vitro cultures their specific histological structure and coordinated vibratory activity, were submitted to infection with polio, adeno, bovine rhinotracheitis, herpes and other viruses. 2) The organized ciliated epithelium when compared with dedifferentiated epithelium in the same cultures showed in all cases a relative resistance to the cytopathic action of viruses, manifested by a marked delay in cell destruction, more pronounced in the case of bovine rhinotracheitis or polio and less marked in the case of herpes or vaccinia viruses. 3) This resistance could not be abolished either by immobilization of cilia with anesthetics or by treatment of cell surface with hyaluronidase or trypsin. 4) The meaning and implication of these data are discussed.

The 6-hour distribution of a tracer dose of Ca⁴⁵ was studied in rats at various intervals after parathyroidectomy and sham operation. In young rats studied one day after parathyroidectomy there was a marked decrease in plasma calcium and a small decrease in the “6-hour exchangeable calcium.” One week after parathyroidectomy there was no further decrease in plasma calcium but a significant further decrease in 6-hour exchangeable calcium. In old rats studied one week after parathyroidectomy there was a somewhat smaller decrease in plasma calcium concentration and no change in 6-hour exchangeable calcium. It is concluded that removal of the parathyroids does not affect the amount of bone calcium available for exchange directly, but may act indirectly in the following sequence: decreased parathyroid hormone → decreased bone resorption → decreased new bone formation → decreased exchangeable calcium.

Bone marrow from species closely and distantly related to the mouse was injected after various X-ray doses to the total body. Rat, hamster, guinea pig, and rabbit bone marrow persisted in normal, nonirradiated mice for not more than 1 day. The minimum X-ray dose that would permit persistence of rat, hamster, guinea pig, and rabbit bone marrow in mice for more than 3 days was 400, 600, 1150, and 1500 r. respectively. The minimum X-ray dose that permitted (a) temporary transplantation of rat and hamster bone marrow in mice was 500 and 600 r, respectively, and (b) prolonged transplantation of rat and hamster bone marrow in mice was 800 and 950 r. respectively. The significance of these findings is discussed.

Pre-sensitization of parental strain donor mice against F₁ hybrid recipients accentuated the foreign bone marrow reaction caused by injection of parental marrow cells into lethally irradiated F₁ recipients. This effect occurred with use of parental strains (101 and C3H) that were histocompatible at the H-2 locus, as well as with those (C57BL and 101) that were histoincompatible at this locus. These results are interpreted to indicate the importance of relative antibody-forming potency of implanted cells, as well as the extent of histocompatibility differences in pathogenesis of the homograft reaction.

5′-adenylic acid deaminase activity of a spectrum of transplantable rat tumor homogenates was determined, and all tumors studied possessed deaminase activity. Activity in the primary hepatoma induced by 3′-methyl − 4 - dimethylaminoazobenzene was equivalent to that of normal liver, while the Novikoff hepatoma and a transplanted hepatoma (MDAB) had significantly higher deaminase activity than either the primary hepatoma or normal liver.

Exposure of Shigella dysenteriae organisms to bactericidal “normal” human sera in the presence of 20% sucrose results in survival of the bacteria and formation of wall-deficient spheroplasts. These “serum spheroplasts” differ from “penicillin spheroplasts” in several respects, including their susceptibility to osmotic shock. The relation of these observations to certain aspects of the phenomenon of bacterial lysis by serum has been discussed.

1) The originally distributed ECHO-13 prototype virus, Hamphill 2–188–20 passage 7, is a mixture of ECHO virus types 1 and 13. ECHO-1 was found in higher titer than ECHO-13 during passage and only the former was isolated at terminal dilution. It was necessary to neutralize ECHO-1 virus with antiserum to demonstrate the presence of ECHO-13 in this mixture and this apparently did not alter its antigenic properties. ECHO-13 virus was successfully reisolated in pure form from the original rectal swab eluate after 4 years storage. 2) Plaque purified strains of reisolated 2–188–20 virus and a Del Carmen 11–4–1 virus isolate were examined as possible ECHO-13 prototypes. The plaque purified 11–4–1 strain produced a broader spectrum antiserum in monkeys in early test bleedings and produced a higher infectivity titer in MKCC. It has been accepted as prototype ECHO-13 by the Committee on Enteroviruses. 3) The biologic properties of ECHO-13 virus in certain animals, chick embryos, cell culture and cell culture fluids are described. A clinically inapparent meningoencephalitis occurred in inoculated monkeys.

On the basis of threshold differences, depth of origin in cerebral cortex and pharmacological selectivity, we conclude that 15 msec. negative potential assignable to activity in apical dendrites and ensuing 150–300 msec. slow negative wave are separate neural processes. Our evidence suggests that the slow negativity seen in the wake of dendritic potential is a sign of an independent post-synaptic process having unusually long time course.