Experimental Biology and Medicine

Injections of purified bovine LH (NIH-LH-B3) in rabbits produced circulating antibodies which were associated with atrophy of the testes and epididymides. Bovine LH and crude rabbit anterior pituitary extract contained a similar antigen which was not a component of normal bovine serum. Results were attributed to an autoimmune phenomenon with circulating antibodies common to NIH-LH-B3 and endogenous gonadotropin.

Although only a few plaques may appear when many vaccinia virus particles are put upon a monolayer of L cells, many cells become infected in areas remote from the plaques. A large fraction of the particles of the inoculum do infect cells and harvest of these from “blank” areas shows that substantial virus growth has occurred.

When neutral solutions of natural dog bile or of synthetic taurocholate labeled with chromatographically pure taurocholate-24-¹⁴C were placed in pouches of the oxyntic gland area of the dog's stomach, total radioactivity decreased. Calculated rate of absorption of taurocholate was greater the higher the concentration of taurocholate in the pouch, and it ranged from 12 to 304 μM per hour. That bile salt can be absorbed from the stomach into venous blood was shown by the fact that when the stomach of an anesthetized dog was filled with a neutral solution of 10 mM bile salts derived from dog bile and labeled with taurocholate-24-¹⁴C, radioactivity appeared in the fluid collected by cannulation of the animal's bile duct.

1. The anti-granuloma, anti-edema and thymolytic properties of corticosterone were studied in intact, thyroidectomized, hypophysectomized or adrenalectomized rats with or without 0.15% thyroid in their diets. 2. Terminal granuloma pellet weights were not much influenced by the operative procedures or by thyroid feeding despite large differences in body weight gain of the various groups. Growth of granulomas was inhibited by corticosterone to a like degree in all groups regardless of endocrine gland ablation or induction of hyperthyroidism. 3. There were no significant differences in the thymolytic effects of corticosterone in the various groups including those in which thyroid feeding alone induced thymic hypertrophy. 4. To the contrary, both the degree of paw edema formed in response to plantar injection of ovalbumin and the prevention of this edema by corticosterone, depended upon other endocrine factors. Thus no significant anti-edema effects of corticosterone were observed in thyroidectomized rats. Thyroid treatment likewise antagonized the anti-edema effects of the steroid in intact or hypophysectomized rats. 5. These data favor the view that cotton pellet granulomas form fairly independently of the hormonal environment of the animal and are inhibited specifically by glucocorticoids. On the other hand, edema formation and its inhibition by glucocorticoids are definitely influenced by the level of circulating thyroid hormone.

Exposure of young, adult rats to electric shock resulted in a significantly elevated level of blood histamine. The pattern of response was related to the animal's sex and pre-shock environment. Females were more sensitive to noxious stimulation than males, as reflected in a more rapid increase and subsequent fall in circulating levels. Post-weaning group living, compared to isolation, was associated with both greater sensitivity and a more pronounced total response. Infantile-manipulated rats had a numerically greater sensitivity and total response, in comparison with non-manipulated controls.

In studies in man, an intravenous infusion of 0.025 μg/kg/min of angiotensin for 5 hours significantly elevated the diastolic blood pressure, but had no effect on the urinary catecholamine or 3-methoxy-4-hydroxy mandelic acid (V.M.A.) excretion rates. The same dose of angiotensin infused intravenously for 1 hour had no effect on fasting blood glucose levels and did not cause glycosuria. It is concluded that catecholamine release does not play a significant role in the vascular responses observed with this dose of intravenous angiotensin in man.

Febrile response of infants to increasing concentrations of standard, intact influenza virus or its ether isolated antigens is compared. Types A-2 and B virus were used. At maximum antigen doses ether treatment eliminated fever induction by the A-2 strain and reduced this property for the B strain. For either serotype, the standard virus vaccine contains at least as much pyrogen as did the corresponding isolated antigen vaccine at 8 times the antigenic mass.

Clearances of ¹⁴C labelled urea, chemical urea and inulin, were determined under steady-state conditions in the toad Bufo arenarum. Clearances of urea were always lower than those of inulin indicating that urea is reabsorbed. In contrast with Rana catesbiana, the kidney of B. arenarum has a very low level of arginase (1.92 μmoles/min/g of wet tissue), and all the other enzymes of the ornithine cycle are present, with the exception of carbamoyl phosphate synthetase. It is demonstrated that no substantial amount of urinary urea is formed in the kidney of this species. The low level of arginase, in a species which reabsorbs urea passively, strengthens the hypothesis that active transport of urea is related to renal arginase activity.

Inhibition of nucleic acid metabolism by 2-thiouracil was investigated using Escherichia coli and an auxotroph which required uracil or orotic acid for growth. Linear increases of 2-thiouracil concentration in minimal salt medium produced logarithmic decreases in the growth rate of Escherichia coli. Uracil reversed the inhibition, and neither growth rate nor growth density was reduced by high concentrations of 2-thiouracil in the presence of the minimum amount of uracil required for growth of the uracil-requiring Escherichia coli. 2-Thiouracil did not inhibit the utilization of uracil and produced only partial inhibition (25%) of the utilization of orotic acid.

Dihydro-L-orotic acid, DL-ureidosuccinic acid, and L-aspartic acid were tested for ability to reverse 2-thiouracil inhibition. Only DL-ureidosuccinic acid clearly reversed this inhibition. An increase in 2-thiouracil concentration did not decrease the ability of DL-ureidosuccinic acid to reverse growth inhibition, indicating that 2-thiouracil does not inhibit L-ureidosuccinic acid utilization, but inhibits its formation or the formation of precursors. L-ureidosuccinic acid precursors are necessary for protein synthesis: thus aspartate transcarbamylase which catalyzes the formation of L-ureidosuccinic acid is considered to be the specific site of inhibition.

Occlusion of a renal artery in anesthetized dogs during mild water diuresis promoted enhancement of the diuresis from the contralateral kidney. The compensation was primarily due to increased free-water clearance and was not accompanied by any significant changes in glomerular filtration rate, effective renal plasma flow, or electrolyte excretion. After vagotomy, a compensatory renal response did not occur, and free-water clearance declined to negative values.

When human thymus, tonsil and appendix cells were exposed in vitro to PHA, PWM or allogeneic lymphoid cells for 2 to 3 days, blast cells were observed. Studies suggest that in mixed lymphoid cultures, the blast cells may have originated from both donors. Infrequently, in cultures containing transformed cells, an absence of H³-thymidine incorporation was observed by radioautography.

A simple, sensitive, and entirely objective bioassay for prolactin is described, using H³-thymidine uptake by the pigeon crop-epithelial tissue only. Doses as low as 1-100 mU of highly purified ovine prolactin (NIH-P-S-7, 24.3 IU/mg), dissolved in 0.5% agar solution and intradermally injected as a gel over one side of the pigeon crop resulted in highly significant increase in H³-thymidine uptake ranging between 59% and 905% as compared to the control sides. A good dose response curve was established. The sensitivity and the objectivity of the method are discussed.

1. An attempt was made to determine whether there is a maternal influence involved in the lethality of rat ova irradiated on the first day of pregnancy. It was demonstrated that 15OR wholebody irradiation was no more deleterious than irradiation of the pregnant abdominal reproductive organs in rats. Therefore, it was concluded that there is no maternal effect due to irradiation of maternal structures other than abdominal reproductive organs at this stage of gestation and dose of irradiation. If a maternal effect exists it may be due to oviduct irradiation or it may be present with higher doses of irradiation. 2. One hundred fifty Roentgens irradiation on the first day of gestation in the rat did not increase the incidence of exencephaly or gross congenital malformations and did not result in fetal growth retardation. These facts and their significance, reported previously reinforce the discrepancy in the incidence and type of malformations induced in the mouse and rat following irradiation on the first day of gestation. 3. Although irradiation of the mouse during the preimplantation period produces a phenomenon referred to as whole-litter resorptions, this does not occur in the rat. Thus, the exencephally reported by Rugh and the whole-litter resorptions reported by Russell and Brent are produced by irradiating the preimplanted mouse embryo, but do not occur following irradiation of the preimplanted rat embryo. These variations in species response must be explained before attempting to apply any of these data to the human.

Further evidence is submitted that a terrestrial mammal, the hamster, has a deep-seated lunar rhythmic component which appears to be derived directly in response to subtle, pervasive geophysical variations. This is reflected in the degree of spontaneous activity and hence would obviously be importantly reflected in standard metabolic rate. The mean monthly range for the motor activity is more than 15%. This suggests that a sol-lunar rhythmic complex such as is now well-established for marine intertidal species occurs also in non-marine forms. It also suggests strongly that fluctuations in hitherto largely disregarded pervasive, weak geophysical variations have substantial influences upon mammals.

Fasted male Sprague-Dawley rats (150-200 g) were exposed to 100% oxygen at 5 ATA pressure for 30, 60, and 90 minutes, and ATP concentration, succinic dehydrogenase activity, % free cathepsin activity, % free ribonuclease activity, acid soluble and total nitrogen, and tissue buffer capacity were determined on brain, liver and kidney. ATP concentrations decreased at 30 minutes, returned toward normal at 60 minutes, and showed marked decrease at 90 minutes. Free ribonuclease activity showed an inverse relationship to ATP concentration. This would implicate ATP in the maintenance of lysosome membrane integrity with respect to ribonuclease permeability. Succinic dehydrogenase activity decreased continuously with time of HPO exposure. Free cathepsin activity increased continuously through the 90 minute exposure in brain and liver. Free cathepsin activity increased in kidney through 60 minutes, but at 90 minutes showed a decrease which is attributed to a marked decrease in both free and total cathepsin activity at this time. Tissue buffer capacity in all 3 tissues showed a decrease in tissue acidity at 30, 60, and 90 minutes of HPO exposure. This is attributed to hyperventilation by the animal during the HPO exposures. Acid soluble nitrogen was normal at 30 minutes, slightly decreased at 60 minutes and markedly increased at 90 minutes in the 3 tissues. This marked increase during the 60 to 90 minute exposure period coincides with the time interval in which the animals exhibited symptoms of acute hyperoxia toxicity. Significance and implication of the results are discussed.

Administration of pharmacologic doses of the sympathetic amine, isoproterenol, to adult female rats resulted in a progressive enlargement of the gland with duration of treatment. Although this enlargement is the result of hypertrophy of acinar cells as well as proliferation of these elements, marked mitotic activity was generally confined to the early days of treatment (1-5 days) whereas hypertrophy was initiated almost immediately and persisted throughout the period of isoproterenol-administration. During the early phase of marked cellular proliferation, chromosome counts from squash preparations of tissue indicated that greater-than-diploid (>2n) as well as diploid (2n) cells were present. Furthermore, the proportion of 2n to >2n changed with time in a highly suggestive way, i.e., at 1-2 days, when mitotic activity was increased above normal, but low, 2n cells predominated; at 3 days, when mitotic rate was maximal, equal numbers of 2n and >2n cells were observed; and at 4-5 days, when mitotic rate dropped, the >2n cells were most evident. Culturing the hypertrophic cells (14 days of IPR treatment) produced only 2n cells. Measurements of nuclei of the enlarged cells, estimations of DNA content by visual examination, and the occurrence of polyploid cells in definite ratios with time all suggest the existence of polyploid nuclei in the enlarged glands.

Hemorrhage causes reduction in the final concentration of salt in the intestinal lumen when the initial solutions are salt-free distilled water or isotonic MgSO₄. The final concentrations increased toward control levels upon reinfusion of the withdrawn blood. The response indicates a functional conservation of salt in the the body under conditions of blood volume reduction.

Ten rats born and maintained in a low pressure, pure oxygen environment did not differ in growth rates from ground level controls. However, overall digestibility was lowered in experimentals. 74.3% vs 79.5% for controls (P<.001), with even greater differences in protein digestibility, 65.5% vs 74.6% (P<.001). Although less fat was digested by experimentals, 75.6% vs 81.4% for controls, these differences were not significant. Net caloric intake was similar due to a slightly greater food intake by experimentals. Calories given off as heat did not differ, suggesting similar metabolic rates.

1. 1 M NaCl-soluble and 0.5 M acetic acid-soluble collagen were purified from pig uterus. The total yield was approximately 0.03% of the weight of the wet tissue. 2. After heat denaturation, the α- and β- components were separated on Sephadex G-200 and CM-cellulose column. Like the finding in human uterine collagen, less α- and more β- components were found in the salt soluble collagen of pig uterus than in the skin of the rat and human being. However, more α- and less β-component were found in the uterine collagen of pig than in that from the human being. 3. Pig uterine collagen contained a somewhat higher level of hydroxyproline and hydroxylysine than dermal collagen of rat and human being.

Changes in cerebral blood flow (C.B.F.) induced by acute exercise (5 minutes of Harvard Step Test at 20/min) were recorded with the aid of an impedance rheograph in 11 subjects (4 males and 7 females) with various degrees of physical training (2 females completely untrained). Flow pulses and their electronic integration were recorded before and after the period of exercise. A substantial increase in the height of the cerebral flow pulses, (males + 27%; females + 49%) and an even larger increase in the integrated recordings, (males + 68%; females + 92%), were observed in all subjects. The increase in C.B.F. lasted for more than 5 minutes after the end of the exercise. A marked increase in heart rate (+42 b/min for males and +61 b/min for females) and a small initial decrease in skin temperature followed 2 min later by an increase were observed also. Changes in heart rate were highly significant but changes in skin temperature were not. The similarity of these responses to those elicited by hypoxia and the possibility of a participation of the chemoreceptors in the cardiovascular and respiratory reactions observed during exercise were noted.

A method for production of plaques by arboviruses in small wells of disposable plastic trays is described. Each of 19 viruses from Central or South America produced plaques in MA-111 and VERO cell lines. Optimum conditions for various agents were determined. The method was shown to give reliable measurement of VEE virus antibodies in sera from humans with naturally acquired infections.

Four test systems were used to demonstrate the analgetic activity of Su-13026, a quinazoline compound, in mice, rats and rabbits. Signs of central nervous system stimulation were noted. Respiration was not depressed in any of the species studied. Nalorphine did not antagonize, nor did amphetamine potentiate, the activity of this compound in mice. Results indicate that this compound has a safe therapeutic ratio and is nonnarcotic.

Volunteers were vaccinated with an inactivated trivalent adenovirus vaccine prepared with adenovirus strains containing SV₄₀ genetic and oncogenic information, enclosed within adenovirus capsids, but no SV₄₀ infectious virus. The volunteers showed marked increases in complement fixing and virus neutralizing antibodies directed against the adenovirus components in the vaccine, but did not respond serologically to the SV₄₀ information. Suckling hamsters injected with the trivalent vaccine or with its monovalent components did not develop tumors over a prolonged observation period. Thus, the SV₄₀ genome contained in the inactivated adenovirus vaccine was inactive antigenically in man and oncogenically in hamsters. The significance of the findings in relation to use in man of killed adenovirus vaccines prepared with adenovirus containing encapsidated SV₄₀ information is discussed.

Two different concentrations of herpes simplex virus were given intravenously to pregnant rabbits. Low concentrations of virus failed to cross the placenta and disappeared from the blood rapidly. A higher concentration of virus produced a viremia of 60-120 minutes and caused the death and resorption of 30% of the fetuses. Virus was recovered from both maternal tissues as well as fetuses, fetal membranes, and fetal fluids.

Pseudomonas aeruginosa, Escherichia coli or Serratia marcescens were uniformly labeled during growth on glucose in a buffered basal salt solution. The endogenous C¹⁴O₂ production of these organisms in dilute suspensions of washed cells was suppressed by glucose under either growth or nongrowth conditions, to a somewhat greater extent under the former conditions. Increasing the concentration of bacteria tended to decrease the extent to which endogenous respiration was suppressed in the presence of glucose. These results suggest that the amount of substrate (or O₂) available per cell is an important factor in controlling the extent of endogenous respiration in the presence of an exogenous substrate.

Trypsinogen was activated by streptokinase-activated plasmin; and the optimal concentration of CaCl₂ was 0.02 M. By avoiding higher concentrations of calcium, and by using a dilute solution of trypsinogen which contained little trypsin, it was possible to limit interference from autocatalysis. Under these conditions, the rate of activation depended on the amount of plasmin. An incubated mixture of urokinase and plasminogen was able to activate trypsinogen, whereas neither urokinase nor plasminogen did so alone.

The inoculation of newborn ferrets with rubella virus by various routes resulted in chronic infection. Specific complement fixing antibody and neutralizing antibody persisted for at least one year after inoculation. Of 36 puppies inoculated by the IC route, 3 showed corneal cloudiness with microblepharon at 6 weeks post-infection. The IC inoculated puppies had the highest titer of virus in most of the organs examined; these animals also showed longer virus shedding, higher CF and neutralizing antibodies. There was no death or evidence of illness which could be attributable to the inoculation of rubella virus by any route. These findings are similar in many respects to those observed in congenital rubella in human infants. The suckling ferret provides a useful model for the study of the prevention and pathogenesis of rubella.

HAggIgG and Tg-antiTg complexes were labelled with I¹³¹ and injected into the peritoneum of rats. These rats were also injected IP with human IgM material, either containing, or free from, RF activity. Animals receiving aggregates plus RF-IgM showed much less radioactivity in the serum, liver, and spleen than controls, 3 hours after injection. Similar findings were noted in the complex-treated animals, except that no difference was noted in serum and evidence was obtained for extensive and rapid thyroglobulin breakdown. In aggregate-treated animals, qualitative differences were also noted in the serum on sucrose gradient centrifugation, suggesting another effect of RF-IgM on aggregate metabolism. Finally it was noted in vitro that extensive RF binding could occur in the Tg-antiTg system, a system which at the same time fixed complement very poorly, if at all.

A modified time-lapse movie chamber used in connection with coverslip cultures in regular culture containers is particularly suited for long-term culture experiments for work with infectious agents.

A protein-free dialysate medium that can be sterilized by autoclaving procedures is described for the growth and sub-cultivation of T. cruzi.

Chloroquine, a 4 aminoquinoline ‘antimalarial’ which binds to DNA, has been shown to inhibit replication of a DNA bacteriophage of E. coli under conditions where growth of the host continues. It is suggested that the ability of the drug to bind to DNA may account for this effect, but a more general metabolic effect cannot be ruled out.

Infection of cells with mengovirus resulted in the leakage of protein which may be taken as a reliable and quantitative measure of cellular injury. Experiments with actinomycin D and streptovitacin A suggested that virus-specific proteins are the cause of protein leakage, and tended to rule out the suppressive action of the viral genome as a primary factor. The appearance of extra-cellular virus and the earliest manifestation of CPE preceded protein leakage by approximately 1 hour.

1. Western equine encephalomyelitis and Eastern equine encephalomyelitis CF antigens were prepared by grinding the brains of infected suckling mice in a borate stock buffer (BSB), allowing the 20% suspension to stand for 24 hours at 4°C, centrifuging, and harvesting the supernate. The “BSB Antigens” prepared in this manner were shown to be of greater potency and sensitivity than commercial products. Inactivation of viral antigens with ethylene oxide gas affected neither the potency nor the sensitivity of the antigen when compared to untreated BSB virus suspension. Ethylene oxide treated BSB mouse brain EEE and WEE CF antigen-antiserum systems did not cross react. 2. Reduction of the incubation time for primary reagents in CF tests from 18 hours at 4°C to 2 hours at 4°C gave little if any change in antiserum or BSB antigen titer. Elimination of the incubation period altogether vitiated the activities of commercial antigens or normal mouse brain, but did not appreciably affect that of the BSB antigen.

Four monkeys were injected with undiluted papovavirus SV40; two of them received the virus with complete Freund's adjuvant. All 4 monkeys developed both complement-fixing and neutralizing antibodies against the structural antigens of the papovavirus. Antibodies against the T antigen induced by the virus were detected in the sera from 3 of the animals. The T antibodies appeared later, attained lower levels and tended to fall earlier than the V antibodies. The specificity of the substance reacting with the T antigen was demonstrated by immunofluorescence tests with cells transformed by SV40 virus and by the SV40-adenovirus hybrid (SP2) and with human and monkey cells infected with the SP2 virus.

African green monkeys repeatedly inoculated with intact simian cells infected with simian papovavirus SV40 or with disrupted infected cells developed complement-fixing antibodies capable of reacting with the virus tumor and virus capsid antigens. The antibody against the tumor antigen appeared first and titers could be maintained or increased by reimmunization of the animals. In addition, virus-neutralizing antibodies were detected. These results demonstrate that antibody against the tumor antigen of the simian papovavirus, an antibody with the same specificity as that which appears in tumor-bearing hamsters, can be elicited in primates in the absence of detectable tumors.

2- [2,6-Diphenyl-4 (1-pyrrolidinyl) cyclohexyl] - pyridine (Su- 15049) caused marked natriuresis and water diuresis in rats without consistent effects on potassium excretion. Its natriuretic actions were abolished by adrenalectomy. In adrenalectomized animals Su-15049 did not modify the response to aldosterone except when the latter was given in the massive doses (0.5 mg/rat) expected to have some glucocorticoid-like effects. Cortisol or corticosterone, however, made adrenalectomized animals responsive to Su-15049, and the presence of cortisol permitted the drug to antagonize the Na-retaining effects of aldosterone. No corticoid substitution therapy was found, however, that enabled adrenalectomized animals to respond to Su-15049 in regard to potassium excretion precisely as did normal ones. Su-15049 has some activity in conventional anti-inflammatory tests.

Formalin inactivated Japanese encephalitis virus vaccine prepared with a recently isolated strain (JEO) in tissue culture of a continuously propagated hamster embryo skin and muscle diploid cell has been tested for potency in mice and monkeys. Several lots of vaccine had a protective potency in the mouse test with intracerebral challenge similar to that required by the Japanese government. In 2 separate experiments in monkeys the vaccine produced substantital titers of HAI antibdy, reduced the amount of viremia after intranasal challenge and protected them from death. The potency of cell culture vaccine was compared to vaccine produced from mouse brain. In the mouse the cell culture vaccine gave better protection against challenge with a low passage strain, while the mouse brain vaccine protected better against the homologous high mouse passage Nakayama strain. In the monkey protection test, cell culture vaccine produced higher HAI antibody and much better protection against intranasal challenge with the low passage strain.

Of 31 cases of acquired hemolytic, anemia with “warm” γG autoantibodies, 17 exhibited positive direct antiglobulin reactions only with anti-γG globulin (Group 1) while 14 gave positive reactions with both anti-γG globulin and anti-complement serum (Group 2). As a preliminary test of Rh-related specificity, autoantibodies eluted from the RBC of patients in both groups were studied for their reactivity with Rh_null RBC. Twelve of 13 eluates showing negative or feeble reactions with Rh_null RBC were from patients in Group 1. Conversely, 13 of 18 eluates which gave reactions of equal intensity against Rh_null RBC and “normal” RBC were from patients in Group 2. The correlation of these apparent differences in antibody specificity with differences in the potential of γG autoantibodies for in vivo complement fixation has been discussed.

Adrenalectomized dogs maintained on mineralocorticoids and salt, for long periods and used frequently for studies of insufficiency and effect of stress upon the circulation, eventually develop chronic low plasma volumes as depressed as those encountered in insufficiency, despite continuation of therapy. The low volume may persist for weeks, months, or until it is raised to normal by glucocorticoids. These animals exhibit normal activity and vigor with blood pressure, blood and plasma constituents little changed from those of normovolemic dogs. The chronic low plasma volume is assumed to be due in part to a generalized, gradual increase in vasoconstrictive activity, thereby reducing free blood flow at the vascular periphery and possibly also to loss of vasodilating reactivity of the peripheral vasculature per se owing to lack of glucocorticoids. These steroids appear active in opening up peripheral vascular channels and are necessary for reestablishing a normal volume of actively circulating fluid.

Adenosine triphosphate raises the plasma volume of dogs possessing adrenal cortices but is without effect in 100 mg doses on the plasma volume of dogs lacking these glands. The negative action of adenosine triphosphate and also that of small (25 mg) ineffective doses of prednisolone per se upon the plasma volume of adrenalectomized dogs when injected singly, becomes highly positive when the two are administered together. These induced elevations of plasma volume in either type of test animal are completely inhibited by G-strophanthin and calcium. Prompt reversal of the inhibition follows administration of salts of K, Mg and Na and is accompanied by sharp increase in plasma volume.

Maternal sera were dialyzed in vitro across individual or combined fetal membranes to elucidate the functions of the membranes in protein transport. Concentration of individual proteins in the dialyzates obtained, closely resembled the composition of amniotic fluid. Results of these in vitro studies indicate that the fetal membranes are able to select protein molecules for passage not only according to size, but also on the basis of their chemical structure.

Urea accumulates in renal tissue during stop-flow in dogs loaded with hypertonic sodium chloride(1). In these experiments stop-flow filtration is relatively high as denoted by creatinine accumulation in renal tissue(2). The tissue concentration of sodium did not change significantly during stop-flow in these experiments or any other experiment performed in osmotic diuresis.

Accumulation of urea in renal tissue suggests, as in the case of creatinine, that urea is trapped in certain portions of the renal tubule as the column of fluid moves along the nephron due to reabsorption of sodium chloride and water from the distal tubule and collecting duct. More explicit information of the side where urea accumulated during stop-flow (lumen, cell, interstitium) may be obtained by a comparative analysis of kidneys with obstructed ureters with kidneys in which the obstruction is released after similar stop-flow periods. If tissue accumulation of urea were due to intraluminal trapping during stop-flow, release of the obstruction should result in a prompt fall in the tissue concentration.

In the light of the above considerations it is the purpose of this paper: 1) to determine the effect of release of obstruction from the ureter on renal tissue concentrations of creatinine, urea and sodium chloride and 2) to use these data and those obtained during stopflow to analyze the relative permeability of the loop of Henle and distal tubule to urea.

Methods. Following 24 hours of water and food deprivation. male and female mongrel dogs (16 to 20 kg) were anesthetized with Nembutal (30 mg/kg). Both ureters were catheterized. Creatinine and PAH were injected intramuscularly in amounts of 0.1 and 0.01 g/kg, respectively. Osmotic diuresis was induced by intravenous infusion of 1.0 osmolar solutions of mannitol or sodium chloride at a rate of 10 ml/min. The infusion

Although urea is generally considered to be a highly permeant non-electrolyte, several lines of evidence have been produced to indicate that the distal part of the nephron has a restricted permeability to urea. The urea concentration of late distal samples collected by micropuncture of rat nephrons has been found to be highly variable, and it was suggested that the variability might be a reflection of varying degrees of permeability (1). When radio-inulin and radio-urea were injected into nephron segments, recovery in the urine was higher with distal tubular injection than with proximal(2). In the former study, interpretation is clouded by the fact that urea is added to the tubular fluid at the level of the thin loop of Henle(1). In addition, differences in contact time may contribute to explaining the results found in both studies. The studies of Capek et al(3) were of a more direct nature. These workers found that the permeability of the distal tubule to urea was 20 times less than the proximal tubule. The authors did not comment, however, on the physiological meaning of this observation and, in particular, did not evaluate if the reduced distal impermeability was low enough to account for accumulation of urea in distal samples.

In dogs, the renal tiiiue concentration of urea is increased during ureteral obstruction hut only in experiments characterized by high levels of stop-flow filtration and low medullary concentration of urea (i.e., NaCl diuresis). The tissue concentration approached the flee-flow levels shortly after release of the obitruction (4).

Intraluminal trapping during stop-flow would imply that the tubule would offer a restricted permeability to urea. Therefore, experiments using the micropuncture technique in rats were designed to test the hypothesis that the increase in the cortical concentration of urea is due to its intraluminal trapping in the distal tubules.

Isolated mitochondria from animals previously treated with growth hormone incorporated more amino acid into protein when succinate was substrate. In the presence of β-hydroxybutyrate and octanoate the mitochondria from fat-adapted animals incorporated amino acid at a greater rate than mitochondria from carbohydrate-fed ones. In this latter study, growth hormone enhanced incorporation rate only in mitochondria from animals fed a high carbohydrate ration.

The uptake of S³⁵O₄ in healing linear urinary bladder wounds of male rabbits was investigated and compared with biochemical studies on the content of acid mucopolysaccharides. The total uptake of radiosulfate was increased from the second day after wounding through the entire examination period of 28 days. Maximum uptake was demonstrated 5 days after operation. The specific activity of the acid mucopolysaccharides was lowered during the first 11 days. This indicated that the increased content of acid mucopolysaccharides in this period was predominantly due to non-sulfated mucopolysaccharides.

An in vitro technique for screening nonsteroidal anti-inflammatory compounds based on their ability to inhibit heat-induced hemolysis of canine erythrocytes has been demonstrated by incubating red blood cells (3.0 ml) as a 40% (v/v) suspension in M 15 sodium phosphate, pH 7.4. for 20 minutes at 53 °C with nonsteroidal anti-inflammatory agents (3.0 ml) dissolved in 0.9% saline. pH 7.4. Lysergic acid diethylamide, phenylbutazone, flufenamic and mefenamic acids, oxyphenbutazone, indomethacin, and aspirin inhibit hemolysis by 40 to 60% at concentrations of 5 × 10^-4 M or less. An inhibition of hemolysis of 28% was significantly different from zero at the 95% confidence level. To determine the specificity of the test, more than 48 nonanti-inflammatory agents were tested.

Evidence is presented which indicates that human cytomegalovirus is relatively insensitive to the antiviral action of interferon in vitro, and that the rate of excretion of cytomegalovirus in the urine of a chronic human carrier was unaltered by circulating levels of interferon in the serum. In human cells in culture, CMV failed to induce the production of detectable levels of interferon. It is suggested that these phenomena may be related to the capacity of the virus to persist in the infected host for long periods. Human cytomegalovirus was also shown to have the capacity to suppress the interferon response of cultures of human tissue infected with other viruses. The implication of this finding for possible synergistic effect of cytomegalovirus with other viruses is considered.

Organ localization of antigen was studied in adult mice. A small tolerance- inducing dose of radiolabeled protein was given to each animal in 4 experimental groups of mice. Radioactivity as an expression of organ distribution of the HGG-I¹³¹ was determined at 4, 8, 24, and 48 hours following HGG-I¹³¹ administration. Blood, bone, brain, lymph nodes, thymus, spleen, liver, kidney, heart, lung and adrenal gland were assayed. A shortage of localization of antigen was found in the lymphoid tissues of tolerant and previously untreated mice. The liver was found to be the organ with the single highest radioactivity in all groups. Lymph nodes showed the highest activity per gram of organ weight. This was primarily significant for sensitized mice. The pattern of antigen distribution in the tolerant animals was interpreted as a failure, early in the immune response, to recognize the foreign material as non-self.

Using polarographic techniques, pO₂ was measured in vivo in the peritoneal cavity of adult rats before and after transplantation of Yoshida ascites hepatoma. It was found that the pO₂ in ascites hepatoma undergoes a progressive lowering during the growth of the tumor. While relatively small tumors are not subjected to a substantial oxygen shortage, oxygen supply becomes progressively more inadequate in the late stages of tumor life.

Psittacosis - lymphogranulomatrachoma agents were isolated from conjunctival scrapings from 9 of 17 sheep representing 3 different flocks afflicted to 90% with follicular conjunctivitis. The PLT agent isolated from follicular conjuctivitis was specifically related to those causing polyarthritis. Ten to 25% of the sheep with eye lesions had polyarthritic signs and the PLT agents were isolated from the blood of 6 of the 17 sheep tested. Parenteral inoculation resulted in follicular conjunctivitis and polyarthritis.

Aspartate transcarbamylase activity was measured in various tissues of Holtzman rats. The distribution of this enzyme is correlated with mitotic activity in all tissues except brain.

Isolated fat cells were incubated in two Krebs-Ringer media containing normal and low phosphate buffer concentrations with 1 g/100 ml albumin. When lipolysis was activated with 10^-5 M NE, a marked acidosis (final pH = 6.6) occurred in the medium of low buffer capacity and the lipolytic activity was significantly inhibited as compared to lipolysis in the medium with normal buffer capacity. This inhibition was partially reversed when theophylline 10^-2 M was added. When fat cells were incubated in these two media, but with glucose present or an albumin concentration of 5 g/100 ml, lipolysis proceeded at a similar rate independently of the buffer capacity of the medium.

Mice inoculated with a leukemogenic virus (Rich) were studied to determine when alkaline phosphatase appears in thymic cells relative to the developing thymic lymphoma. The findings indicated that the enzyme increase occurs only after the tumor is definitely established, hence this change cannot be causally related to the neoplasm.

Thymic cells from newborn rats and mice and from 2 human fetuses were killed by incubation with prednisolone (10 μg/ml) for 1 day. In contrast, thymic cells of newborn rabbits were resistant to the hormone. Thymic cells from young rabbits acquired increasing sensitivity with age and the cells from 12-week-old or older rabbits were nearly all killed by prednisolone. Lymphocytes from the spleen and appendix of rabbits were moderately sensitive to the cytocidal action of prednisolone. Many thymic cells from the human fetus were transformed by PHA into atypical lymphoblastoid cells but very few thymic cells from neonatal and adult rabbits were transformed.

Experiments were performed in the rat to determine whether the increased secretion of growth hormone (GH) during stress involves augmentation of synthesis and/or release of hypothalamlc GH-releasing factor (GRF). Two different stimuli were used as stress: injection of formalin, which was previously shown to be ineffective in inducing GH release; and cold exposure, which evoked depletion of pituitary GH. Exposure of rats to cold (4°C) for 1 hr resulted in a significant depletion of pituitary GH, which was accompanied by disappearance of hypothalamic GRF and appearance of GRF activity in plasma. Cold exposure for 5 minutes was ineffective. Injection of 10% formalin did not induce pituitary GH depletion, or affect hypothalamic and plasma GRF activity. These results indicate that some stressful stimuli, such as cold exposure, capable of releasing GH, induce this effect via the hypothalamus; other stresses, like formalin injection, which do not release GH, exert little effect on the GH-release mechanism of the hypothalamus.

Retardation of the rate of insulin degradation results in a highly significant insulin effect upon glucose utilization by the rat kidney. Insulin inactivation may be inhibited by lowered incubation temperature or the in vivo and in vitro administration of alloxan. These observations suggest that under appropriate conditions, tissues heretofore believed to be insulin-insensitive may be shown to respond to insulin.

Hemagglutinin responding capacity to sheep erythrocyte antigen in 3-year-old BC3F₁ mice was approximately 10% of the response in normal young adult mice. The reduction in primary antibody-forming capacity was determined in aged animals that had no specific lesion of lymphatic tissue such as lymphoma, lymphosarcoma, suggesting that the reduction was primarily due to unspecific atrophy or degenerative changes. Results of splenectomy in the aged mice suggest that the spleen is the major source of immunological competence in the aged animals and that the reduced immune capacity in these mice is not due simply to failing spleen function.

AAV antigens could not be recognized in cells by immunoifluorescence unless the cells had been infected with adenoviruses. Of the adenoviruses studied, (types 1, 2, 4, 6 and 12) type 12 was by far the most efficient helper virus. A measurable fraction of adenovirus infected cells failed to produce recognizable AAV antigen (s). AAV super-infection suppressed the number of adenovirus infected cells producing recognizable adenovirus antigens. The FF assay method employed was at least 1,000 times more sensitive than electron microscopy and 10,000 times more sensitive than complement fixation for detecting AAV.

The use of plastic Petri plates for cell growth and FA staining resulted in substantial savings in time and effort, and gave more uniform results than did glass coverslips. Our results suggest that this procedure is precise and valid for quantitation. The technique was used to titrate adenovirus 2, 12, AAV and reovirus.

Intravenous glucose tolerance studies showed no impairment of glucose utilization in atherosclerotic dogs. It was observed, however, that administration of vitamin A to atherosclerotic dogs did produce a significant increase in glucose utilization.

Resting potentials of frog muscle fibers incubated in normal or high-potassium Ringer's solutions are maintained for longer periods of time by the addition of aldosterone. This response is absent in ouabain-Ringer's solution. Although based upon separate groups of muscles, the results indicate that muscle fibers in high-potassium Ringer's solution are slightly hyperpolarized when ouabain also is present.

Phytohemagglutinin (PHA), poke weed mitogen, and streptolysin-O, all agents capable of stimulating mitosis in human lymphocytes in vitro also stimulated the production of an antiviral substance with biological, chemical, and physical properties identical to those of human interferon. Upon removal of PHA from human lymphocyte cultures interferon production ceased within 2 hours. Readdition of PHA resulted in reinitiation of interferon production.

The effect of antibiotics on pancreatic lipolysis was studied in vitro. Neomycin and some other antibiotics inhibited lipolysis at concentrations below 3 mg per 100 ml. These antibiotics may directly effect pancreatic lipase or alter the physico-chemical state of the substrate.

Colloidal carbon ink (C11/ 1431a) and various commercial gelatin preparations were pyrogenic in rabbits. Cross-tolerance studies indicated the existence of endotoxin in pyrogenic gelatins. Three of seven gelatin preparations depressed carbon phagocytosis in rats when administered 30 minutes prior to the clearance test; however, no significant correlation existed between gelatin pyrogenicity and depression of phagocytosis. All 3 RE interacting gelatins had alkaline isoelectric ranges. Gelatin pretreatment depressed a subsequent carbon clearance while endotoxin induced a marked but delayed increase in carbon phagocytosis. Chronic injections of endotoxin markedly stimulated the RES as reflected in enhanced phagocytosis and splenomegaly; in contrast, chronic gelatin administration produced no such effects. It appears that the influence of gelatin on the RES is not mediated solely by a pyrogenic endotoxin contaminant.

Monomethylhydrazine (MMH) was injected into rats, rabbits, and guinea pigs, and subsequent levels of methemoglobin in the blood were measured. Peak levels of methemoglobin occurred within an hour, but were less than 5% of blood hemoglobin with doses of MMH up to 0.54 mmoles/kg. In contrast, 5 to 8-fold higher levels have been previously observed in anesthetized dogs treated with comparable doses of MMH. In vitro incubations of MMH with blood from rats, rabbits, guinea pigs, dogs, and human subjects produced peak levels of methemoglobin within an hour. Peak levels were 4 to 8-fold higher when human or canine blood was incubated with MMH than when rat, rabbit, or guinea pig blood was similarly incubated. These results demonstrate that there is a marked difference among species in the levels of methemoglobin found either in vivo after MMH injection or in vitro during incubation of blood with MMH.

Pretreatment of dogs with 20 mg/kg of indomethacin blocked some of the hemodynamic effects of endotoxin. In the treated animals i.v. injection of the LD₈₀ dose of endotoxin (E. coli) caused a significantly smaller transient fall in the first phase of shock than in the control group. After the initial brief fall, the arterial blood pressure stayed at normal level for the duration of the experiment in dogs that received indomethacin. This was in contrast to the characteristic decline of arterial pressure in the untreated dogs in the second phase of shock. Administration of indomethacin lowered the rectal temperature and portal venous pressure of dogs. The results were discussed and compared to those obtained with other anti-inflammatory agents.

Using a strain of Escherichia coli ATCC 9637 resistant to 8-azaguanine, a microbiological assay has been developed for a new broad spectrum antimicrobial compound, methyl 5 (or 4)-(3,3-dimethyl-1-triazeno)-imidazole-4(or 5)-carboxylate (NSC 87982). As little as 0.75 μg of NSC 87982/ml of sample can be detected. The applicability of this assay has been demonstrated for the estimation of concentrations of this drug in various tissues of mice.

Hamsters offer several likely aspects in their use as producers of antibodies. (1) They produce large volumes of ascitic fluid containing high titer antibody. (2) They provide a source of antibody free of anti γG globulin and, therefore, rich in non γ antibody specificity. (3) The hamster provides suitable system for preparation of homologous antibody to viruses which either require the hamster as a host or for which the hamster is used to isolate and/or maintian the virus. An interesting facet of this study was the finding of extensive cross-reactions between human and hamster plasma proteins.

Human serum proteins have been fractionated by agar gel electrophoresis. Clear resolution was achieved which allowed direct comparison of patterns from various samples by visual inspection. Quantitative and qualitative changes from normal patterns were correlated with clinical conditions. The procedure is rapid and useful for screening and monitoring serum protein patterns and for differentiation of pathological conditions by visual evaluation of their serum protein patterns.

The influence of transferrin saturation on the enhancement of iron absorption by intraluminal histidine or intraluminal fructose was studied in rats. A loop of lumen immediately distal to the pylorus was perfused in vivo with a solution containing Fe⁵⁹. The greatest amount of Fe⁵⁹ absorption was noted when the perfusate was supplemented with histidine or with fructose. When the perfusate in the intestinal lumen was not supplemented, or when it was supplemented with histidine, increase in transferrin saturation did not influence the iron absorption in each instance. However, when the perfusate contained fructose, the transferrin saturation had a lessening effect on the amount of iron absorbed. Histidine supplement to the perfusate caused a rapid transit of iron across the intestinal mucosa, since there was significantly less iron retained in the mucosa in the face of a high level of iron absorption.

The saluresis of mercaptomerin and ethacrynic acid in dogs was measured in terms equivalent to urinary osmotic pressure and electrical conductivity. When converted into identical units (millimols or milliequivalents of NaCl per liter), these concentrative properties are shown to provide unique pharmacologic parameters of renal function such as the relative salinity or ionic fraction of the total solute concentration. In conjunction with specific electrolyte analyses, e.g., Na, K, and Cl, expressed in similar equipollent units (mEq/l), other singular relationships in urinary function are demonstrable.

Large amounts of insulin appear in the bile of rabbits after i.v. administration of 2 mg (50 IU) of bovine insulin. Insulin was recovered from the bile also after the administration of heterologous insulin in low concentrations. The hormone concentration in the bile reached a peak in the first 30 minutes after i.v. injection of insulin, showing that the bile is avenue for the loss of insulin from the circulation.

1. The apparent antibacterial activity of nitrofurantoin (pKa 7.2) against E. coli, S. aureus, and Pr. vulgaris is increased as the pH of the medium is lowered. 2. P. aeruginosa becomes susceptible to nitrofurantoin in the presence of 1% or more urea and in an acidic medium (pH 6). 3. Incorporation of 2% NH₄Cl as a urinary acidifier in the diet of rats did not have a major effect on the nitrofurantoin concentrations attained in the urine or on the total amount of nitrofurantoin excreted. 4. The ingestion of a high protein diet by albino rats to increase urea excretion did not adversely affect the urinary concentration nor the total amount of nitrofurantoin excreted. S. Albino rats receiving 0.1% nitrofurantoin (about 10 × calculated human dose) and 2% NH₄Cl in the diet for a 2-week period showed no evidence of crystalluria or kidney pathology.

1) Rates of anaerobic CO₂ production by tissue obtained from dog kidneys with evidence of cortical ischemia have been compared with tissue from non-ischemic kidneys. Anaerobic CO₂ production rate was consistent with the following coupled oxidation-reduction reaction: α-ketoglutarate + oxaloacetate + GDP + P₁ → malate + succinate + CO₂ + GTP. 2) Cortical washed homogenates from non-ischemic kidneys produced 14.6 ± 1.8 μmoles CO₂/100 mg dry wt hr (M ± SE); cortical homogenates of ischemic kidneys yielded 6.0 ± 3.0 μmoles of CO₂ (P<0.05). Similar studies done on slices revealed no such difference between ischemic and non-ischemic kidneys. 3) The activity of α-KG-dehydrogenase was the same in washed cortical homogenates of both ischemic and non-ischemic kidneys. In contrast, malic-dehydrogenase activity was significantly lower in cortical homogenates of ischemic kidneys. 4) Thus, cortical blanching is associated with a specific change in cortical mitochondrial enzymic activity so that both cortex and medullary homogenates have decreased capacities for complete oxidation of substrates. This specific difference in the enzymic activity of mitochondria from the ischemic cortex may explain, in part, the low activity of the above reaction in ischemic cortical homogenates and may be one of the initial metabolic changes which occurs in the ischemic kidney.

The lipid composition of the carcass of mice bearing the Krebs-2 carcinoma for periods varying from 1 to 5 weeks was determined. The only change of questionable significance occurred after 5 weeks of tumor growth at which time the carcass neutral lipids were decreased and the phosphatides were increased. Prior to the 5th week the neutral lipids increased somewhat. No change was found in the amount of the carcass neutral lipid classes—the tri-glycerides, sterol esters, cholesterol, mono- and diglycerides and free fatty acids—as a result of the growth of the Krebs-2 carcinoma. Furthermore no significant change was found in the fatty acid composition of the free fatty acids, sterol esters and triglyceride of the carcass lipids following growth of the carcinoma from 1 to 5 weeks.

The effect of immunization of donor mice with bacterial antigens, on the capacity of their spleen cells to product graft-vs-host (GVH) disease has been investigated for irradiated adult recipients differing from donors at the H₂ locus. Fatal GVH disease produced by spleen cells from untreated control donors was a function of the number of cells transferred. Antigen pretreatment of donors caused a reduction in the capacity of their spleen cells to produce GVH mortality. Compared with equal numbers of cells from untreated mice, the magnitude of this reduction was proportional to the total quantity of antigen used in pretreatment: 1.4 mg of Serratia marcescens polysaccharide (SMP) decreased donor spleen cell reactivity to 1/5 of control levels whereas 0.12 mg produced a decrease of 1/4 and 0.01 mg to somewhat less than 1/2 that of controls. Salmonella enteritidis polysaccharide (SEP) also provided reduction of donor cell GVH reactivity however when employed in similar dosages (SMP 120 μg, SEP 210 μg) SMP was substantially the more active in inhibiting subsequent GVH reactions. In addition, the very low toxicity of SMP permitted its use at much higher and more effective dosages.

1. When mice bearing established, solid Ehrlich carcinomas were treated with pentaerythritol tetranitrate, there was an increase in the localization of Evans blue dye in the tumors. Epinephrine caused a decrease in the dye recovered from the tumors. 2. When mice bearing solid Ehrlich tumors were treated with pentaerythritol tetranitrate, heterologous antitumor serum (adsorbed) and normal guinea pig serum, 60% of the tumors regressed if treatment was continued for 5 weeks or longer. The administration of guinea pig serum may have been unnecessary.

Glycogen content of the rachitic rat tibial epiphyseal cartilage is determined during healing induced by vitamin D or starvation. Rachitic rat cartilage contained 8.61 μmoles glycogen per gram net weight of tissue. Following a single dose of vitamin D (4000 I.U.) the glycogen content was not significantly altered at 24 hours, but was decreased to 6.16, 5.50 and 4.45 μmoles at 48, 72 and 96 hours respectively. Fasting caused a rapid decrease in the glycogen content to 4.45 and 2.50 μmoles at 24 and 48 hours respectively. Vitamin D treated rat cartilage oxidized glucose to a greater extent than the corresponding untreated controls. It is suggested that glucose and glycogen metabolism stimulates the formation of calcifiable matrix by the cartilage cell. Fasting for 48 hours caused a marked fall in serum calcium and a rise in serum phosphorus level.

A portion of the acid-labile CO₂ in alkaline extracts of rat muscle is not precipitable by BaCl₂. Carbonate added to an extract that has been acidified, freed of CO₂ by evacuation, and realkalinized is only partially precipitated. It is concluded that barium solubility is the effect of some substance in the muscle extract in inhibiting crystallization of a limited amount of BaCO₃. Calculation of intracellular pH from total acid-labile CO₂ appears valid.

Autoantibodies to germ free rat colon were produced in rats by repeated intraperitoneal injections with newborn rabbit colon in Freund's complete adjuvant. Antibodies were assayed by means of indirect hemagglutination of sheep erythrocytes sensitized with a heat stable phenol-water extract of germ free rat colon or by fluorescent antibody staining of rat colon sections. The response of rat colon injected rats was less intense. A few of the rats injected with adjuvant alone also developed an anti-colon titer. Hemagglutination inhibition experiments demonstrated that the antibodies were specific for gastrointestinal antigen and represented autoantibodies in a true sense. They were found to be specific for at least three different colon determinants: one unique for germ free rat colon, one common for rat and rabbit colon, and one common for both colons and a polysaccharide from Eschericria coli O:14, grown on synthetic medium. No or only very weak cross reactions appeared with similar antigens extracted from a number of other E. coli strains. Old Tuberculin and extract of Staphylococcus aureus were inactive. The pattern of reactivity of the rat antibodies was similar to that of patients with ulcerative colitis. Stimulation by cross reacting bacterial antigen may be an important contributing factor for autoantibody formation in this disease.

Rabbit anti-mouse thymocyte serum significantly modified the course of mouse LCM virus infection. Clinical and histologic signs of infection were absent so long as therapy was regularly maintained, and the severity of the host response to the virus was reduced following discontinuation of prolonged therapy. Treatment in the early period of incubation was more protective than at later times.

The susceptibility of primary cultures from monkey kidney, human embryonic kidney, human embryonic lung, and human amnion cells, and of WI-38 and KB cells, to 23 prototype strains of group A coxsackieviruses was studied. All types except A1, 5, 6, 19 and 22 could be propagated in one or more of the various cell cultures used. The property of MgCl₂ stabilization was established for all 18 prototype viruses that can be grown in tissue culture.

A naturally occurring compound, cycasin (methylazoxymethanol-beta-D-glucoside), and its aglycone and the aglycone acetate were tested for the induction of sex-linked recessive lethal mutations in Drosophila. Cycasin was not mutagenic but methyl-azoxymethanol and its acetate were potent mutagens.

Sera from patients with farmers' lung, pigeon breeders' disease, bagassosis, and maple bark strippers' disease were examined for the presence of precipitating antibodies against the corresponding antigenic materials. All sera showed reactions with 3 or 4 of the antigens. The one exception was the serum from the patient with maple bark strippers' disease, which reacted only with the antigens thought to cause the disease.

Neuroblastoma cells from 8 children and dissociated human sympathetic nerve cells from 10 fetuses were grown in tissue culture. Sympathetic nerve cells from all of the fetuses and 5 of 8 neuroblastomas rapidly incorporated H³-norepinephrine or its precursor, H³-dopamine. There was a more rapid turnover of these catecholamines in the tumor cells than in the normal fetal human sympathetic nerve cells. Three neuroblastomas showed little or no incorporation of these amines.

The sensitivity of a standard interferon assay was increased by exposure to poly-L-ornithine during interferon treatment. The enhanced titers thus demonstrated are interpreted as indicating an increased interferon uptake by the cells.

Elevated and variable serum levels of LDH in control rats were found to result from the commonly used method of collecting the blood by cardiac puncture and from the preparation of serum for analysis. Evidence is presented that LDH from heart, red blood cells, and platelets are contributing factors to this discrepancy. When blood was collected from the inferior vena cava and plasma was immediately prepared in plastic tubes for analysis instead of serum, the extraneous factors were largely eliminated. These modifications were employed for the determination of LDH and isoenzymes in untrained rats subjected to 4 hours of swimming, and in untrained controls. The data indicated a 3-fold increase of LDH activity in the plasma of exercised rats. LDH-isoenzyme determination and histological examination indicated that probable sources of the increased LDH activity were the heart, liver, and skeletal muscle.

Mouse liver NCTC #1469 and mouse skin L-929 strain cells vary markedly in their susceptibility to organophosphorus insecticidal compounds. In mouse liver cells, the 50% growth inhibitory level of cytotoxicity was measured as 1804 μg/ml of medium for malathion, 310 μg/ml for Cygon®, 11 μg/ml for DI-Syston®, and 2 μg/ml for Dipterex®. The low toxicity of malathion to mouse liver cells correlates well with its low toxicity to the mouse but contrasts with its high toxicity to human liver Chang strain cells. Mouse liver cells were more susceptible to malaoxon than to malathion, but human liver cells were almost equally susceptible to malaoxon and malathion. Differences in cell susceptibility are largely due to the rates of malathion biotransformation to malaoxon, a more toxic and more potent acetylcholinesterase inhibitor. When tested at concentrations below acute toxicity levels, malathion, Cygon, and DI-Syston stimulated mouse liver cell growth.

Rats that received alphanaphthyl-isothiocyanate (ANIT) in their food developed intrahepatic bile duct hyperplasia. Immunochemical studies revealed additional antigens in the ANIT treated liver compared to that of the normal liver. These antigens were shown to be localized in the basal membrane of the intrahepatic bile ducts.

Three hundred and sixty-nine Marine Corps recruits, initially without either complement fixing or toxin neutralizing epidemic typhus antibodies, were studied to determine their antibody response to subcutaneous injection of decreasing doses of commercially produced epidemic typhus vaccine administered in 1 or 2 doses of 1 ml each. When immunized with either 1 or 2 doses of undiluted vaccine or with 1 dose of vaccine diluted 1:2 or 1:4 91 to 100% of the 194 marines responded by developing either complement fixing or toxin neutralizing antibodies, or both. About 1/3 of 116 marines who received 1 dose of vaccine diluted 1:16 or 1:64 developed these antibodies. A single dose of vaccine diluted 1:256 elicited demonstrable antibodies in 15% or 9 of 59 men. These results suggested that the amount of antigen contained in 2.0 ml of vaccine required in the basic course of the immunization regimen was more than was needed to accomplish reasonable antibody responses in man. Accordingly, the primary immunization regimen for epidemic typhus for military personnel in the United States was changed in 1963 from 2 1-ml doses of vaccine given 7 to 10 days apart to a single 0.5 ml dose on entrance into military service and another 0.5 ml dose of vaccine at the time of overseas assignment.