Experimental Biology and Medicine

NMB was given in one subcutaneous injection in oil at a dose of 6 mg to female rats on nitrogen and body weight balance. A constant level of food was consumed. A highly significant and prolonged nitrogen retention was obtained. No nitrogen excretion rebound was seen. A significant increase in body weight was produced which was maintained for 19 weeks.

A clonal strain (MH₁C₁) of rat hepatoma cells synthesized labeled bilirubin with either glycine-2-¹⁴C or δ-ami-nolevulinic acid-3,5-³H as precursor. In contrast to the findings in living rats, labeled bilirubin production is only slightly enhanced in MH₁C₁ cells that have been preincubated with phenobarbital. These studies indicate that hepatic parenchymal cells are capable of producing at least part of the nonerythroid fraction of bile pigment. Moreover, they provide a unique experimental model for the further study of hepatic heme and bilirubin metabolism.

Administration of prolactin to hypophysectomized rats maintains luteal function. When rat and sheep prolactins were given at the same dose (IU) rat prolactin was found to maintain luteal function for a greater number of days. This duration exceeded the length of pregnancy in the rat.

Serum prolactin concentrations were determined by radioimmunoassay during estrus cycles in 15 dairy heifers bled by repeated jugular punctures or from a long, indwelling jugular catheter. The method of bleeding was found to influence the serum prolactin concentration and was attributed to nonspecific stress. Further confirmation for the stress effect was provided by a controlled study in other heifers, submitted to specific forms of acute and chronic stress stimuli. In cattle, studies of blood prolactin concentrations under various physiological conditions may be performed only when environmental conditions are carefully controlled.

A method for isolation of mammary gland cell nuclei was described. DNA-dependent RNA polymerase activity in isolated mammary gland nuclei was measured in rats fed a single dose of DMBA. In female rats, there was a significant inhibition of Mn²⁺-(NH⁴)₂SO₄-activated RNA polymerase activity within 24 hr after the feeding of DMBA. Inhibition continued for 2 days, but thereafter, the enzyme activity rose significantly above the control value. In contrast, RNA polymerase activity was not depressed in male rats treated with DMBA.

Inhibition studies, carried out using a partially purified L-asparaginase 2 preparation, have indicated that tobacco smoke and a number of reactive smoke components do not cause inhibition. Of the smoke components studied, only acrolein was inhibitory and this inhibition was found to be more marked at pH 8.4 than at pH 5.0. The -SH specific reagents, sodium arsenite and p-hydroxymercuribenzoate did not inhibit the enzyme.

Cobaltous chloride in concentrations up to 8.0 mM in human red cell suspensions in a Krebs-Ringer-bicarbonate-glucose media produced significant hemolysis under O₂ but not under N₂. Both O₂ and cobalt have significant hemolytic effects and appear to greatly potentiate each other. Hemolysis favors methemoglobin accumulation in the extracellular fluid, but O₂ has an additional effect in the opposite direction. By keeping the hemoglobin saturated, oxygen tends to prevent auto-oxidation of the pigment to methemoglobin. Thus, methemoglobin accumulation in erythrocyte suspensions exposed to cobalt is a net result of several opposing effects, but no evidence was obtained to suggest that cobalt is a specific inhibitor of methemoglobin reductase.

A method of isolating large numbers of metaphase chromosomes from normal, regenerating rat liver is described. The chromosomes were separated into size groups in a large-capacity zonal rotor (B-XV) on sucrose density gradients.

Hemagglutinating antibodies to native DNA were found to occur selectively in NZB/W mice and rarely in other strains. In contrast, antibodies to single-stranded DNA and double-stranded RNA have a more widespread distribution. They occur in NZB and NZB/W mice as well as other strains of mice. Poly A·poly U and poly I·poly C are shown to be immunogenic in mice without the use of Freund's adjuvant or in vitro coupling to a protein carrier.

The antilipolytic activity of the beta-adrenergic blocking drug, 4-(2-hydroxy-3-isopropylaminopropoxy) acetanilide (practolol), was examined using the isolated fat cell preparation. The compound was found to be a competitive inhibitor of hormone-stimulated lipolysis with low intrinsic activity. As determined by pA₂ values the compound was 80-100 times less potent than propranolol. In contrast to propranolol, practolol did not inhibit the lipolytic response to dibutyryl cyclic AMP nor ACTH. Practolol also failed to inhibit glucose oxidation.

Gel filtration chromatography and spectral analysis of copper-containing fractions from rat bile suggest that the major fraction of biliary copper is associated with amino acids and small peptides.

Following adrenalectomy or hypophysectomy? bile flow was significantly decreased suggesting that adrenal steroids regulate biliary copper excretion by choleretic action.

Squirrel monkeys fed a semi-purified diet to induce atherosclerosis showed a high incidence of gallstones, which began to appear 3 months after the start of the atherogenic diet. The incidence in animals maintained on this diet for over 9 months was 83%. The gallstones consisted essentially of pure cholesterol and increased in size, number, and total mass of stones during the period of feeding. The cholesterol: phospholipid ratio in bile was highest in the group and in the individuals with stones. Monkeys fed a natural diet had very low ratios and were free of gallstones.

In a rhesus monkey immunized by cercariae of S. japonicum exposed to high doses of X-irradiation, the perishment of challenge cervariae was found mainly in the skin. Thus our former statement that a strong resistance against schistosome infection in rhesus monkeys can be induced by previous immunizations with cercariae exposed to a large amount of X-irradiation is confirmed. The fact that the perishment of the immunizing cercariae took place in the skin of the rhesus monkey, and the death of the challenge cercariae occurred also in the skin, strongly suggests that a stage specific anti-schistosomular antibody may function in this case.

The in vitro effect of dieldrin (HEOD) on respiration of rat liver mitochondria was studied. It was found that HEOD inhibited mitochondrial respiration at a site prior to the DNP-sensitive coupling site. Further work showed that HEOD inhibited electron transport in the mitochondrial electron chain in the cytochrome B area; terminal chain electron transport was not effected by HEOD. The effect of HEOD was dependent upon the level of mitochondrial protein and not on the molar concentration of the pesticide in the reaction mixture.

An equation was derived which permits the calculation of the residual radioactivity in plasma at the end of 1 hr following intravenous injection of ⁵⁷Co B₁₂. This equation gives the residual activity on the basis of the distribution of in vitro added ⁵⁷Co B₁₂ to serum vitamin B₁₂ binders as determined by DEAE-cellulose column chromatography.

The addition of 1.0 mM fluorocitrate to kidney slices markedly inhibited gluconeogenesis from citrate, while 10.0 mM malonate did the same to gluconeogenesis from glutamate. Both inhibitors increased ammonia production from glutamate by kidney slices. Injections of malonate and fluorocitrate into rats increased ammonia excretion in vivo despite no significant change in urine volume or pH. Therefore, both in vivo and in vitro, a slow down in citric acid cycle activity by two agents blocking at different points in the cycle resulted in augmented renal ammoniagenesis.

Attempts were made to learn if SV40-transformed cells are resistant to super-transformation by infecting SV40-trans-formed clones of 3T3 with SV40. No alteration of growth properties was detected after SV40 infection of four cloned lines of SV40-transformed 3T3 that had stable low saturation densities. In contrast, SV40 infection of polyoma-transformed 3T3 having comparable saturation densities yielded easily detectable double transformants. Two lines of 3T3, which had been transformed by UV-inactivated SV40 and did not release virus upon fusion with permissive cells, were super-infected with SV40. After dilution of residual virus by cell growth, the superinfecting virus could not be recovered from either of the cell lines upon fusion with permissive (GMK) cells. Two lines transformed by a temperature sensitive large plaque mutant of SV40 were infected with temperature resistant small and minute plaque mutants. Fusion of the cells with GMK at the permissive temperature was effective in releasing the initial transforming mutant from both clones, but no superinfecting (temperature resistant) virus could be detected at either the permissive or nonpermissive temperature. We conclude that if super transformation occurs with SV40 it is an uncommon event, for superinfecting virus could not be recovered, nor could cells with altered growth properties be detected.

The hearts of magnesium-deficient mice accumulate less ³H-digoxin 1 hr after intraperitoneal injection than do controls. At 3, 6, 18, and 24 hr, magnesium-deficient mice retained more ³H-digoxin than controls. The difference in the initial uptake of ³H-digoxin between control and magnesium-deficient animals is not due to different blood ³H-digoxin levels. The role of magnesium deficiency-induced potassium deficiency in altering myocardial ³H-digoxin metabolism is discussed.

Quazodine (6,7-dimethoxy-4-ethylquinazoline, MJ 1988) was up to 6 times as potent as theophylline in inhibiting PDE partially purified from a number of rabbit tissues and beef brain. As with theophylline, inhibition of PDE could be the underlying mechanism for the bronchodilator and cardiovascular effects of quazodine.

Aortic pressure, right atrial pressure, heart rate, and cardiac output were measured; and mean pressure, stroke volume, and peripheral resistance were calculated in 27 male beagles before and after 5000- or 10,000-rad whole body doses of mixed gamma-neutron radiations. The response of these beagles to levarterenol, phenylephrine, or metaraminol was also determined before and after irradiation. Irradiation caused a decrease in aortic pressure, cardiac output, and stroke volume; and an increase in heart rate. Peripheral resistance increased, but not significantly, in irradiated beagles. Phenylephrine and metaraminol were equally effective before and after the dogs were irradiated, while levarterenol was more effective in irradiated dogs. The results are interpreted as follows: (i) radiation induced hypotension cannot be fully explained by radiation effects on peripheral blood vessels; (ii) pressor drugs are effective in irradiated beagles with hypotension, and drug effectiveness is probably decreased only as a terminal event shortly before death; (iii) any direct effect of radiation on the heart is of limited significance in whole body exposure.

It has been reported previously by two groups of investigators that portacaval shunt in rats is followed by the increased enzymatic synthesis of histamine in the gastrointestinal tract and by the elevated excretion of histamine in urine. The purpose of our experiment was to determine whether side-to-side portacaval shunt affects the urinary excretion of radioactive histamine following the injection of radioactive histidine. Female rats with shunts and sham-operated animals received ³H-L-histidine intravenously. Urine was collected from these animals for four 24-hr periods and analyzed for ³H-L-histamine. The expected elevation of urinary histamine in shunted animals was not found. The excretion of ³H-histamine was lower in animals with portacaval shunts than in controls. Shunted animals excreted more urine than sham-operated rats. The results of this preliminary experiment do not support the hypothesis of an increased synthesis and excretion of histamine in animals with portacaval bypass.

Male rats were accustomed to a two-meal-a-day feeding pattern of diets containing either medium-chain triglycerides (MCT) or long-chain triglycerides (LCT). Fat comprised 40% of calories in these diets. Before the morning meal, rats fed the MCT diet had higher blood ketone and plasma nonesterified fatty acid levels and lower blood glucose and plasma triglyceride levels than the LCT-fed rats, suggesting that the MCT-fed rats may have been in the postabsorptive state for a longer time.

After the rats received the morning feeding, the MCT-fed rats showed a rapid decline in plasma NEFA levels and a greater rise in blood glucose levels than LCT-fed rats. The high fasting blood ketone levels decreased in both groups, but the MCT-fed rats maintained a higher level than the LCT-fed rats even after the meals.

Postprandial hypertriglyceridemia was observed in both groups. However, in the MCT-fed rats the triglyceride level returned to the fasting level by 2 hr after the meal; whereas the hypertriglyceridemia was sustained for at least 5 hr after the meal in the LCT-fed rats. This finding probably relates to the more rapid and complete digestion of MCT compared to LCT.

When human blood was drawn into a syringe containing heparin and pumped through a column of glass beads, over 90% of the platelets were retained. Platelet retention was markedly reduced if the blood was first disturbed by inversion in a tube, slow centrifugation and remixing, or rapid back-and-forth transfer between two plastic or glass syringes. Retention was restored within 1 hr after the last-named maneuver but could be reduced again by redisturbing the blood. The high platelet retention noted when blood inverted in a tube was passed through columns prepared in Bowie's laboratory indicates the marked effect of the plastic tubing and beads.

The distribution of injected ³²P was studied in the mildly hyperammonemic chick and rat. Ammonia toxicity in the chick resulted in decreased accumulation of ³²P in the tibia (p<.001) and decreased level of labeling in the inorganic phosphate fraction of blood (p<.001). Toxicity in the rat also resulted in decreased accumulation of label in the tibia (p<.005), but increased incorporation in the liver (p<.005), kidney (p<.005), and urine (p<.001), indicating that injected ammonia probably converted inorganic phosphate into a form that was eventually treated by the body as a waste product. Changes in organic blood metabolites accompanying ammonia toxicity in the chick paralleled those described earlier for the rat and pig.

The results of this study represent the first direct evidence that low doses of ammonia administered to laboratory animals interfere with phospate metabolism.

Cell fusion between mouse mammary tumor cells and normal mouse cells not only enhanced the production of MTV, as demonstrated by immunofluorescence and electron microscopy, but also appeared to induce infection of normal nonfused cells. In cultures of mouse tumor cells fused with normal rat mammary cells, a definite species specificity of the mouse MTV has been shown, since this virus seemed to replicate exclusively in the mouse tumor cells. In both cases, cell fusion appeared to lower the compatibility barrier of rat recipients to mouse cell transplants but a subsequent infection of the host by MTV could not be demonstrated.

N-Demethylation of codeine by morphine tolerant male rats decreased significantly as compared to nontolerant male rats to the level of nontolerant female rats; whereas in the nontolerant female rats, female mice, and tolerant male mice, it was not changed.

Dystrophic rabbit muscle showed a decrease in total nitrogen, noncollagen nitrogen (NCN), dry weight and dry fat-free weight (DFF wt). Collagen nitrogen and the fat content of the tissue were found to be increased over that seen in the controls. Livers of E-deficient animals displayed a 40% rise in total nitrogen and NCN versus normals. Aldolase activity was markedly decreased in dystrophic muscle, but liver revealed an elevation in its enzyme concentration compared to controls. The elevation of serum aldolase in E-deficient rabbits preceded and paralleled the creatinuria associated with the development of dystrophy by a period of 1 to 2.5 weeks. These conclusions were compared to those observed in other forms of muscle wasting.

The fetal-maternal ratios of serum phenylalanine in the rat have been measured in the fasting state and 1, 2, and 3 hr after intravenous phenylalanine loading. Resuts indicate that fetal levels are always higher than maternal and that the fetus metabolizes the transplacental load less rapidly than its mother. This suggests that any woman with hyperphenylalaninemia who becomes pregnant should have her blood phenylalanine maintained below 8 mg/100 ml of blood at all times if the fetal brain is to remain undamaged.

Injections of hemoglobin or hemin stimulated erythropoiesis in rats and gerbils but were without effect in normal or polycythemic mice. Attempts to demonstrate increased erythropoietin levels in plasma of hemoglobin-treated rats were unsuccessful. Injection of antierythropoietin serum abolished in gerbils the hemoglobin-induced increase in erythropoiesis. No evidence was found that hemoglobin increased the erythropoietic response to erythropoietin. It is concluded that hemoglobin exerts its erythropoiesis-stimulating effect by inducing small increases in erythropoietin.

Increased urine volume and increased water intake were shown in genetically obese rats. The increased urine volume persisted despite controlled solute intake and pitressin treatment. Maximum urine concentrating ability and urine proteinuria were similar in lean, genetically obese, and lesioned obese rats. No histological lesions could be identified. The results were discussed in the light of a possible hypothalamic defect in genetically obese rats.

Ninety dogs at different ages (from days 2 to 60) were tested for their emetic responses to graded doses of apomorphine injected intravenously and to copper sulfate administered orally. None of the 2-day-old puppies vomited in response to apomorphine, up to a dose of 1 mg/kg. However, some did vomit when given 20 or 40 mg of copper sulfate. The reactivity to copper sulfate increased remarkably from days 2 to 5, and thereafter it remained almost unchanged up to day 60. The reactivity to apomorphine first appeared at day 5 and increased remarkably up to day 10. Thereafter, it continued to increase at a much slower rate up to day 30, at which time the ED₅₀ was very close to that of adults. These results suggest that the emetic response mediated by the chemoceptive emetic trigger zone (CTZ) did not function at the second day after birth, but that the vomiting center could be excited by impulses from the gastrointestinal tract, and that the vomiting center and CTZ matured at different rates in puppies.

A calf serum fraction with sulfation factor activity was shown to stimulate growth of HeLa cells in Eagle's minimum essential medium supplemented with “nonessential” amino acids and bovine serum albumin. The results are discussed in light of the influence of pituitary growth hormone on sulfation factor activity in serum and of similarities in effects of the latter and insulin.

The population doubling time for lines of FL human amnion cells infected with mycoplasma fermentans (strain HT) was increased (30 hr) compared to uninfected FL cells (17.5 hr). Infected FL cell lines from which mycoplasma was eliminated, had a doubling time of 21 hr and showed an increased resistance to reinfection, even several years after the mycoplasma elimination. Although the amounts of cell-associated mycoplasma were similar to those of infected FL cells, cytopathic effects and cell destruction were much less pronounced after reinfection of such lines. The amounts of cell-associated, as well as free mycoplasma, were reduced in cultures of primary amnion cells as compared to the transformed cells. Primary amnion cells were highly resistant to mycoplasma infection as judged by the number of glass-attached cells and lack of cell destruction. The theoretical and practical implications of these observations are discussed.

A polyoma-transformed cell line of proven tumorigenicity is demonstrated to have greater tRNA methylase activity than its nontumorigenic parent cell line when cultured, harvested, and assayed under controlled conditions. The marked differences in capacity to methylate heterologous tRNA substrates suggests, but does not prove, that qualitative differences may exist between the methylases of the paired cell lines.

Blast cell transformation in vitro of lymphocytes obtained from the peripheral blood of guinea pigs after sensitization to mycobacterial antigen was shown to increase after PPD stimulation. However, the cellular activity of lymphocytes was influenced by recent sensitization or immunization of the animals. The blastogenic response of guinea pig lymphocytes to the mitogen PHA was decreased following both the initial tuberculin sensitization and skin testing with PPD. Lymphocytes from tuberculin-sensitized animals demonstrated a fall in responsiveness to in vitro PPD stimulation after the animals were skin tested.

Furthermore, this study shows that in vitro NDV infection of sensitized lymphocytes prevents the cells from undergoing PPD-induced transformation. This confirms earlier work on viral-induced lymphocyte unresponsiveness and establishes the guinea pig as an animal model for investigating the virus-lymphocyte relationship.

The effects of a single injection of gold thioglucose (GTG) and bipiperidyl mustard (BM) on the pituitary prolaction and GH contents of C3H mice were studied. Virtually all mice receiving the drugs became obese in 8 weeks. GTG and BM increased pituitary prolactin concentration 37 and 24% at 4 weeks and 42 and 40%, respectively, at 8 weeks (p<0.01). GH concentration was enhanced significantly (30%; p<0.01) only by BM treatment at 8 weeks, BM increased the weights of the pituitary glands, adrenals, ovaries, and the uteri; whereas only the uterine weights were increased by GTG treatment. The data suggest that prolactin and/or GH may be related to the induction of obesity by GTG and BM.

Virions of NDV show strain specific variation in the proportions of proteins which they contain.

Ovarian ascorbic acid depletion activity was detected in adenohypophyses of sexually mature female green anoles in April, May, and June. The equivalent of five April glands from anoles lacking oviducal eggs, but with heavily yolked, unovulated eggs, evoked depletion approaching that evoked by 0.31 μg of LH.

The incorporation of acetate and fatty acids into rat platelet lipids was studied by incubating washed platelets with acetate-1-¹⁴C or albumin-bound fatty acids-1-¹⁴C (palmitic, oleic, linoleic, and linolenic acid) in an artificial medium without addition of cofactors. Acetate was incorporated primarily into PC, TG, CEM, FFA, and PE which accounted for three-fourths of its total incorporation into lipids. Palmitate incorporation into platelet lipids was twice as high as that of each of the unsaturated fatty acids. A distinctive pattern of distribution of palmitate or of the unsaturated fatty acids among the various lipid classes was observed as well as differences in the relative abundance of the fatty acids incorporated into each PL group. Rat platelets are therefore capable of (i) incorporation of fatty acids from the suspending medium, and (ii) de novo synthesis of fatty acids, Pattern of fatty acid incorporation and rate of de novo synthesis appear to be different from those in human platelets.

Human and rabbit globulins possessing Escherichia coli agglutinating activity reacted with antigens present in normal and diseased (ulcerative colitis) rectal mucosa. The direct immunofluorescent staining technique gave positive results when OB E. coli strains were tested. Staining was most marked in the basement membrane of the nucosal glands, and in the basal portion of the acinar epithelial cells. Sections of ulcerative colitis rectal tissue showed increased staining of interstitial leukocytes. The observed effects were independent of the donor blood types and did not follow the distribution of blood group substance in rectal mucosa.

Ninety-six serial serum specimens collected prior to exposure and during the incubation period and acute phase of transfusion-associated hepatitis in 13 patients were tested for interferon. None was found. Two each of the patients had hepatitis-associated antigen, antibody to such antigen, or anticomplementary activity. Failure to detect interferon in hepatitis patients may be related to the tendency of viral hepatitis, in some cases, to become a prolonged or chronic disease.

The effect of 6-azauridine, an inhibitor of RNA synthesis, has been shown by 2 experimental methods to inhibit the replication of measles virus within mammalian cells in vitro. In a direct virus titration in which the drug was incorporated in the agar overlay, 6-AZ not only reduced the infectivity of measles virus but also delayed plaque development. Experiments designed to test the effectiveness of 6-azauridine when added to cultures at intervals after infection, showed that this uridine analog was capable of reducing the amount of infectious virus produced by each infected cell, and that the drug is more effective when added early in the infection cycle.

This experiment was designed to determine whether the genetic differences in blood pressure found between the A/J and BALB/cJ and between the A/J and SWR/J strains were due to different loci in the BALB/cJ and SWR/J strains or due to different alleles carried at the same locus. It was found that after four generations of selection the mean blood pressure of the SWR/J was exceeded by 7 mm Hg in males and 17 mm Hg in the females. The results could not be due to different alleles at the same locus since the selected genotype would be the same as the SWR/J genotype at that locus and should not have a more elevated blood pressure than the SRW/J strain. Since the blood pressure in the selected line exceeded that of the SRW/J, each of the two strains (BALB/J and SWR/J) must have contributed different alleles at more than one locus to the original gene pool in the F₁ and F₂. It is also concluded on the basis of genetic selection theory, that the difference between mean systolic blood pressure of the two inbred strains is due to the action of at least three loci.

Marked and sustained elevation of systolic and diastolic blood pressure results from the continuous iv infusion of angiotensin II in anesthetized dogs.

The administration of hydralazine, sodium nitrite, and hexamethonium (10 mg/kg, iv) produced a fall in blood pressure in angiotensin-induced hypertensive dogs. However, hydralazine failed to produce a hypotensive response in normotensive dogs. This suggests the possibility that antihypertensive drugs may be evaluated in dogs made acutely hypertensive by angiotensin II infusion.

We have studied the effect of changes in the oxygen tension of incubating media on Na transport in the toad bladder. Solutions containing 10% oxygen will support approximately 80% of the aerobic short-circuit current obtained with 100% O₂. When the oxygen tension is reduced below 10%, the SCC falls sharply. The toad bladder will survive exposure to 100% N₂ for periods of at least 90 minutes with little loss of its ability to transport Na.

Progestin and sterol secretory capacity of rabbit ovarian interstitial tissue was investigated with and without LH. Based upon ovarian content and upon synthesis in vitro, progesterone and 20α-ol secretion increased within 5 min after intravenous injection of LH. At 2 hr after LH injection, interstitial tissue content of progesterone and 20α-ol were about 3 and 4 times larger and in vitro syntheses were 4 and 12 times larger than controls. By 8 hr after LH injection, progestin synthesis returned to near control levels and stores of cholesterol and esterified cholesterol were depleted to 60 and 23% of control levels. Synthesis by ovarian interstitial tissue of progestins and sterols in vitro was enhanced by LH in the incubation medium, especially among the rabbits not injected with LH. This steroidogenic response to LH in vitro was reduced within, 5 min and abolished within 2 hr after intravenous injection of LH.

Isolated perfused rat liver experiments were performed using livers from male and female donors. Radiolabeled endrin added to perfusates appeared in bile of livers of male donors 2 to 12 times as rapidly as in bile of livers of female donors. These findings explain the lesser toxicity and lesser adipose tissue storage of endrin in male rats, and further validate the isolated perfused liver technique as a useful method of insecticide toxicology.

(i). The guanine + cytosine content of S. mansoni has been shown to be 34.4 moles % on the basis of its buoyant density in CsCl and 34.9 moles % on the basis of its ultraviolet absorbance-temperature profile.

(ii). Antibodies to DNA have been demonstrated in hamsters infected with S. mansoni and humans infected with S. japonicum. These antibodies show a broad specificity and react with DNAs of parasite, bacterial, and mammalian origin.

(iii). Circulating DNA has been demonstrated in the serum of hamsters infected with S. mansoni.

(iv). It is suggested that schistosomiasis, in some instances at least, exhibits autoimmune or immune-complex disease.

Pre treating mice for 3 days with equimolar doses of various inducing agents resulted in an increase in liver size, microsomal protein, and cytochrome P-450. The largest increases were produced by chlorcyclizine and phenobarbital and could be correlated with a decrease in hexobarbital sleeping time noted in a previous study. These agents were more active in weanling and dietary restricted mice than in fed adult mice. Hexobarbital and antipyrine caused smaller increases in microsomal protein and cytochrome P-450 and were not as effective in decreasing hexobarbital sleeping time. Pre-treatment with 3, 4-benzpyrene increased the cytochrome concentration in both the fed adult and 27% casein-fed weanling mice but decreased hexobarbital sleeping time only in the weanling mice. The microsomes derived from adult mice pretreated with 3, 4-benzpyrene gave an aniline difference binding spectrum which differed from that seen in the weanling mice.

Actinomycin D was employed to profoundly enhance the sensitivity of mice to endotoxin in order to bioassay submicrogram amounts of endotoxin. Homogenates of rat liver and spleen were able to detoxify endotoxin as bioassayed in actinomyein-treated mice. Lung, kidney, heart, and brain homogenate did not possess the ability to significantly detoxify endotoxin. Lead acetate, which profoundly sensitizes rats to endotoxin, enhanced the vascular clearance of colloidal carbon and also reduced detoxification of endotoxin by liver and spleen homogenates. Enhanced phagocytosis, resulting in accumulation of endotoxin in macrophages, coupled with the failure in endotoxin inactivation or detoxification, appears to be the mechanism of lead acetate-induced endotoxin hypersensitivity.

Studies were made on the changes in the lipid pattern of adipose tissue in a lizard during hibernation, arousal, and activity. A relation appears to exist between the fat composition of the adipose tissue and the lizards seasonal physiological state. Adipose tissue shows a marked increase in size and lipid content during the prehibernation and hibernation periods. Arousal resulted in a two- to threefold reduction in the tissue weight and its fat content, and this remained low during activity. Triglycerides always represented the bulk of the lipid fraction. During arousal and activity the levels of EFA and cholesterol were reduced. Despite the alterations in the fatty acid pattern of triglycerides, especially in the levels of palmitic, palmitoleic, stearic, and linolenic acids, there was no change in the total unsaturation during hibernation, arousal, and activity. The relative proportions of the lipolytic products (FFA, DG, and MG) were increased during arousal and activity, and were associated with marked variations in their fatty acid composition which may be related to variable metabolic rates for these acids.

Human transplanation antigens, HL-A1 and HL-A2, have been obtained from cells of a single hematopoietic line which has both antigens. HL-A1 has been obtained essentially free of HL-A2. Both have a molecular weight of about 48,000. They appear to be of protein nature and can be labeled with radioiodine. The radioactive antigens permit the use of sensitive radioimmunoassay methods for identifying and quantitating HL-A antigens.

Three immunologically distinct unsaturated (without vitamin) vitamin B₁₂-binding proteins have been demonstrated in humans. Intrinsic factor, the best known, has a molecular weight of 55,000 and promotes the uptake of vitamin B₁₂ by the intestinal epithelium (1, 2). Transcobalamin II, a liver-synthesized serum B12 binder with a molecular weight of 35,000, is apparently responsible for the uptake of the vitamin by the tissues (1, 2). A third binder, R binder or transcobalamin I, has a molecular weight of 110,000 and is found in serum, saliva, gastric juice, and a variety of other body fluids (1, 2). The function of this binder is not known.

It has been shown recently that chickens have a single unsaturated serum B¹² binder with a molecular weight of 113,000 and an immunologically similar proventriculus B₁₂ binder with a molecular weight of 96,000 (3). These binders superficially resemble the human R binders. They are approximately the same size as the human R binder, and in both cases immunologically similar forms occur in both the serum and gastric juice. However, antibody against the chicken binder does not react with human R binder (3). The present study demonstrates the presence of unsaturated B₁₂ binders in amphibians. These resemble neither the human binders nor the chicken binders.

Materials and Methods. Levels of unsaturated vitamin B₁₂ (B₁₂) binders were measured using zirconyl phosphate gel (Z-gel), a highly negatively charged gel that binds proteins below their isoelectric point (4, 5). B₁₂-⁵⁷Co was purchased from Philips-Duphar, Holland, and was diluted with unlabeled B₁₂ to give solutions containing either 100 ng/ml (1000 counts/ng) or 10 ng/ml (10,000 counts/ng). B₁₂-⁶⁰Co was used as purchased (1 μCi/1.484 μg or 0.652 μCi/μg; E. R. Squibb and Sons, New York).

The temporal relationship of various physiological and biochemical alterations in adjuvant arthritis was presented. The parameters measured included hindleg edema volume, local hyperpyrexia, grip function, serum lysozyme, peripheral blood leukocytes, and body weight. The injection of M. butyricum (in oil) into the hindpaw of Lewis rats produced increases in the injected hindleg volume and temperature, elevation of serum lysozyme, and loss of body weight gain. These alterations occurred in a biphasic pattern which corresponded temporally to the primary and secondary phases of adjuvant arthritis. Increases in the uninjected hindleg volume and temperature, impairment of grip function, and increases in peripheral blood leukocytes occurred mainly in the secondary phase of the disease. Local hyperpyrexia, elevated polymorphonuclear leukocytes, and impairment of body weight gain were the earliest detectable signs of the onset of the secondary phase in adjuvant arthritis. Edema volume, local hyperpyrexia, impairment of grip function, and elevated serum lysozyme levels appear to be diverse expressions of the inflammatory process in adjuvant arthritis as well as the human disease. The assessment of these parameters in the animal model may have utility in defining the profile of potential antiarthritic agents.

Cholesterol biosynthesis was studied in male rats from mothers fed a vitamin B₁₂ deficient diet during pregnancy and lactation. Deficient males had significantly lower plasma cholesterol levels, the ester fraction being diminished. Adrenal cholesterol was appreciably higher, relative to levels observed in the B₁₂ fed rats, while cholesterol content of testes and brain was not significantly different between the two groups. Vitamin B₁₂ deficiency enhanced the rate of acetate incorporation into liver cholesterol while mevalonate incorporation remained unchanged after 30 min and 2 hr but was markedly lower in the deficient group after 4 hr. Mevalonate incorporation into adrenal and testicular cholesterol was also reduced at 4 hr but incorporation into brain cholesterol was unchanged.

Injection of 1.0 mg of AGP postponed ovulation for 24 hr in immature rats, pretreated with 3 IU of PMS, presumably due to inhibition of ovarian steroidogenesis. This block was completely prevented by estradiol and testosterone, administered 1 hr after AGP. Progesterone or LH administered on day 24 also prevented the block of ovulation by AGP.

In a continuing evaluation of adenovirus sensitivity to interferons the limited but measurable sensitivities of Ad. Types 1, 3, 4, 5, 8, 11, and 18 to human tissue culture interferon were demonstrated in plaque-reduction assays using human embryo kidney cell cultures. Generally similar patterns of interferon-mediated interference were observed for each virus type and for several strains within a single serotype. Similar findings have been reported previously for Ad. Types 2, 7, and 12 (6). The relatively limited sensitivity of adenoviruses to interferons seems to set them apart from many other animal viruses and reinforces a number of recent reports of intrinsic differences in sensitivity to interferon among different viruses.

Lesions were located in the ME of ovariectomized rats to determine their effect on plasma levels of FSH, LH, and prolactin as determined by RIA. Initial levels of FSH and LH were elevated as a result of removal of steroid feedback from the ovaries. One week after placement of lesions plasma LH levels had fallen, 32-fold, to very low values. There was a lesser, 3-fold, fall in FSH, and a dramatic, 15-fold, rise in prolactin to levels nearly as high as those observed in lactating rats and in females in proestrus. In sham-operated controls, in which the electrodes were lowered into the hypothalamus stopping short of the ME, no significant changes were seen in the plasma levels of all three hormones. The results demonstrate that the release of LH and to a lesser extent FSH is decreased after removal of hypothalamic control, whereas the release of prolactin is greatly enhanced.

Male rats, fed ad libitum, were exposed to 100% oxygen at 450 mm Hg for periods of time varying from 1 to 3 weeks. After exposure, blood lipid assays were performed and in vitro incorporation of acetate-2-¹⁴C into CO₂ and fatty acids by slices of liver and epididymal adipose tissue was measured. The oxygen-exposed rats gained a greater amount of weight over the exposure period than did their isocalorically, pair-fed controls. Plasma lipid values obtained from oxygen-exposed rats were higher than those obtained from the pair-fed group. Fatty acid contents in liver and adipose tissue of the oxygen-exposed rats were higher than those obtained from the pair-fed control rats. Conversion of acetate to fatty acids was found to be significantly higher in adipose tissue of O₂-exposed rats than that of nonexposed controls. A similar difference was not found in the case of slices of liver obtained from the same two groups of rats. The possibility that the oxygen-enriched environment alters the utilization of foodstuffs in a manner which more efficiently conserves energy by the storage of greater amounts of fat and/or greater synthesis of lipids is discussed.

Bilaterally ovariectomized does were maintained on 1 μg of estradiol benzoate/kg of body wt/day and given various levels of either progesterone (P) or 20-α-hy-droxyprogesterone (20α-OHP) following mating to fertile bucks. Compared with estrogen-treated controls, a single injection of 0.5 and 1.0 mg of 20α-OHP and 0.15 mg of P increased the number of ova fertilized. Higher levels of either progestin reduced the number of fertilized ova recovered in the capacitation test system. A doe thus prepared can be used several times in a short period to capacitate sperm. Unilateral ovariectomy of the capacitator doe had no effect on the number of ova fertilized in the test system.

To test the hypothesis that coitus enhances capacitation by stimulating pituitary release of gonadotropin, naturally mated mature rabbit does were treated with sodium pentobarbital. Pentobarbital reduced the number of ova fertilized in the capacitation test system to the level seen in unmated untreated does. Progestin levels measured in peripheral blood of the capacitator does treated with pentobarbital failed to increase following mating. Human chorionic gonadotropin given to pentobarbital-treated does increased the number of ova fertilized in the test system and restored the increase in peripheral progestin levels.

The utilization of α- and amide nitrogen as sources of supplemental nitrogen to reduce nitrogen losses in the adult rat was studied using the nitrogen balance technique. Although young rats have been shown to utilize amide less efficiently than α-amino nitrogen as a source of supplemental nitrogen for carcass nitrogen gains, adult rats utilized the two equally well. Level of calorie intake or nutritional state of the adult animals did not influence the results.

RNA from the spleens of immunized mice was separated by electrophoresis in polyacrylamide gels. Estimates of the molecular weight of various species of RNA was made by this method. Two peaks of especial interest were noted. They corresponded to RNAs with molecular weights of size approximating the theoretical requirements for messengers for antibody H chains and L chains. Their rate of synthesis as measured by the incorporation of ³H-uridine increased after immunization and X-irradiation of the mice before they were injected with antigen inhibited the appearance of the relevant peaks. They were considered to contain messenger RNAs for antibody although undoubtedly contained nonantibody-specifying RNAs of similar molecular weight.

Vitamin A deficiency enhances the in vitro capacity of rat liver ribosomes to make protein. This stimulatory effect of vitamin A deficiency on protein synthesis is due to the pH 5.1 enzyme fraction.

Newborn rats fed restricted calories during the first 2 days of life showed a depression of brain weight, and the levels of glutamic acid, glutamine, alanine, serine, and GAB A compared to those allowed to suckle their mothers normally. Also it was found that the levels of valine, leucine, isoleucine, histidine, arginine, cystine, ornithine, urea, and ammonia were increased in newborn rats maintained on restricted calories. It is concluded that calorie malnutrition, even for a short period, during the neonatal development is associated with alteration in the brain amino acid pool.

Arylamidase catalyzed hydrolysis of a variety of dipeptides and oligopeptides was investigated. The N-terminal residue must be an α-amino acid of the L-configuration. The penultimate residue must also be of the L-configuration. Substrates with straight or γ-branched nonpolar side chains on the N-terminal residue were most susceptible to arylamidase catalyzed hydrolysis. Substrates with β-branched or polar side chains on the N-terminal residue were quite resistant to arylamidase catalyzed hydrolysis. Substrates having nonpolar side chains on the penultimate residue were hydrolyzed quite rapidly regardless of the branch point. Amino acid amides are hydrolyzed by arylamidase.

Intact rabbit testes contracted autorhythmically in vitro with a frequency of 2-3 beats/min. When (PGE₁) was added to the bathing media, there were alterations in amplitude of contractions, rate, overall tone, and mode of contraction. At relatively high levels of PGE₁ (greater than 36 nM) the contractions were completely effaced; with lower concentrations of PGE₁, recovery was evident after 5 to 6 min. The effects of PGE₁ on amplitude, rate, and tonus were dose-dependent. The above observations, plus those of other workers that prostaglandins are present in mammalian testes, that a mechanism for their synthesis appears to be present in this organ, and that these compounds modulate androgen synthesis and inhibit testicular capsular contraction, suggest a possible physiological role for these unsaturated fatty acid derivatives in normal testicular function.

During the 24-hr period after 70% hepatectomy, rats kept without food were found to maintain blood glucose levels comparable to those of sham-operated controls. As indicated by measurements of L-alanine-¹⁴C and H¹⁴CO₃ incorporation into glucose and net glucose production, the rate of gluconeogenesis in liver slices was higher for the partially hepatectomized rats than for sham-operated controls. The enhanced gluconeogenesis exhibited by the residual tissue from the hepatectomized animals was not accompanied by increase in the activity of either glucose-6-phosphatase and fructose-1, 6-diphosphatase.

Three groups of 50 rats each were exposed for periods of up to 24 days to either hypoxia (70 Torr PI_O2 ), hypercapnia (140 Torr PI_O2 , 60 Torr PI_CO2 ), or a combination of this level of hypoxia and hypercapnia.

The combined condition resulted in a much smaller rise in circulating red cell volume per body weight than in rats exposed to hypoxia alone. The increase that did occur could be mainly attributed to a release of stored red cells into the circulation. During hypercapnia, plasma volume increased with only small changes in numbers of circulating red cells. This resulted in a depression of hematocrit.

It is still not clear whether concomitant hypercapnia increased oxygen levels in the hypoxic-hypercapnic rats sufficiently to remove the erythropoietic stimulus, or if CO₂ actually inhibited erythropoiesis.

Twenty g/100 ml of glucose or fructose solutions at a dose of 2 g/kg were injected into the fetal circulation of pregnant sheep over a gestational age range from 110 days to term. Fourteen fructose injections and 8 glucose injections were carried out in a total of eight fetuses. Fetal plasma insulin concentrations increased significantly after either fructose or glucose injections. After glucose injection, the rise in fetal plasma insulin concentration was most marked and fructose concentrations in the fetal circulation increased.

Circulating lymphocytes from five normal individuals and from five patients with neoplastic disease were unequivocally stimulated by irradiated cultured lymphoid cells of lines established from the same donors. This reaction suggests that there is an antigenic disparity between these two types of cells. It is possible that the surface antigens of lymphoid cells may change during multiplication in an in vitro environment.

The in vitro response to phytohemagglutinin (PHA) and pokeweed mitogen (PWM) of lymphoid cells from thymectomized, irradiated, bone marrow reconstituted (TIR) mice was compared to that of intact age controls. TIR spleens, lacking cells of the thymus-dependent compartment, responded only to pokeweed mitogen, whereas spleens from intact donors responded to both PHA and PWM. These results suggest that PHA stimulates thymus-dependent cells; whereas PWM stimulates cells of the non-thymus-dependent compartment.

The administration of endotoxin to BCG-infected mice induces a marked sensitivity to insulin. When insulin is administered after endotoxin, a profound hypoglycemia ensues. The stimulation of endogenous insulin secretion in endotoxin-poisoned BCG-infected mice by glucose administration may also lead to a reactive hypoglycemia from which the mice do not recover. These observations illustrate the loss of homeostatic control caused by endotoxin and are consistent with previous observations that endotoxin impairs gluconeogenesis.

The ability of GF rats to generate sensitivity responses has been compared to that of isogeneic CV rats. It was demonstrated that GF rats reject skin allografts more rapidly than do similar CV rats. In vitro correlates of delayed- and immediate-type sensitivity are produced more rapidly and in greater strength to transplantation antigens. Increased responsiveness was also demonstrated to H and O antigens of E. coli and to sheep erythrocytes. This occurs because a larger proportion of the immunologically competent cells of the GF animal's smaller immune system responds to an antigenic challenge.

We suggest, although we have not proven, that this may be due to increased ability to process antigen.

The infusion of the pancreatic ducts with obstructed duodenal contents (Pfeffer fluid) produced a constant fall in the systemic platelet counts whether or not the animals subsequently developed severe pancreatitis. This fall in platelet count was not prevented by aspirin, sodium salicylate, or dipyridamole in the doses used nor did these agents have any beneficial effect on the subsequent pancreatitis. Aspirin appeared to aggravate the degree of pancreatitis.

Subcutaneous doses of cephalothin and cephaloridine and oral doses of cephalexin were administered to rats. The 3 antibiotics rapidly entered the blood serum and bone: peak concentrations were reached 15–30 min after administration. The antibiotic activity in the bone was dependent on the coexisting activity in the serum for each of the compounds.

The effect of Mg on the secretion of CT was studied in pigs. Infusion of magnesium was shown to increase the secretion of CT. During the latter part of sustained infusions, this relationship appears directly proportional up to very high concentrations of magnesium. Increased secretion of CT occurred under conditions of decreasing plasma calcium levels. Both total and ionizable calcium decrease in response to the increased CT level elicited by the infusion of magnesium. Thus, the influence of Mg on CT secretion is an important factor to consider in evaluating CT secretion rates.

Certain nitroso compounds studied in hamsters have been found to cause tumors mainly in the respiratory tract (1). Diethylnitrosamine (DEN) also had a transplacental carcinogenic effect in hamsters (2). When the litters of treated and untreated mothers were exchanged, tumors were found only in the offspring of carcinogen-treated mothers nursed by untreated mothers. The offspring of untreated mothers nursed by mothers treated with carcinogen until the end of pregnancy showed no neoplastic alterations in the respiratory tract (3). We were able to show the presence of nitroso substances in the placenta and fetus of treated pregnant hamsters. Therefore, it was assumed that under these conditions, little or no carcinogen reached the young via the milk after delivery. In the experiments reported here, the effect on the young of carcinogen administered to mothers during lactation was studied.

Materials and Methods. In this set of experiments, 6-month-old hamsters were treated with high doses of DEN or dibutylnitrosamine (DBN) 1 to 30 days after delivery. Three groups of five animals received sc administrations of 5, 10, and 20 mg/kg of body weight of DEN dissolved in water. Three other groups received 300, 600, and 1200 mg/kg of body weight of DBN in olive oil (Table I).

Results. Nearly one-third of the offspring in the DEN groups died while nursing, showing acute toxic alterations in the liver and kidney. These changes were not observed in the DBN groups or in the controls. The experiments are still underway, with approximately 50% of the young still living more than 1 year after the treatment of their mothers.

Focal hyperplastic and dysplastic alterations of the mucosa in the trachea and nasal cavity were seen in treated mothers. All mothers also had tracheal papillary tumors.

Stomach emptying was significantly inhibited by actinomycin D administration (100 μg/100 g), after a 24-hr fast, to rats intubated with a ¹⁴C-labeled casein hydrolysate. Four hr after intubation 45% of the radioactivity remained in the stomachs of actinomycin D-treated rats; whereas, only 3% was present in those of saline-treated controls. The decreased rate of amino acid incorporation into liver and serum protein reflected the blocked state of the stomachs of drug-treated rats. In addition to the retention of radioactivity there was an actual increase in total stomach content of the animals receiving actinomycin D. In drug-treated rats an increase in stomach content (1.5 ml of fluid) was also observed 4 hr after administration of actinomycin D in fasted rats that were not intubated with casein. In addition, the drug stimulated a bizarre appetite. Treated rats consumed large quantities of wood shavings and neoprene if accessible, besides indulging in a marked degree of coprophagy. The reciprocal relationship between stomach and liver radioactivity levels suggests that failure to observe induction of hepatic enzymes by diet in studies using actinomycin D-treated rats could result from insufficient availability of inducers, rather than the more commonly credited inhibition of RNA synthesis.

Total urinary glycosaminoglycans (GAG) and urine volumes were measured in relation to perineal size during the menstrual cycle in the baboon. Perineal deturgescence was accompanied by a marked increase in urine volume. The increase in urine volume was in some cycles accompanied by a marked transient increase in urinary GAG. This increase was due largely to non-sulfated GAG, tentatively identified as hyaluronic acid and lower molecular wt products derived from it. Evidence is presented, showing that these GAG originate in the perineum. The results show that when nonsulfated GAG are mobilized from the baboon perineum by normal regulatory mechanisms, they are not quantitatively reflected in urine, suggesting the presence of effective mechanisms for their degradation.