Showing papers in "Experimental Biology and Medicine in 1951"
TL;DR: In an experimental investigation being carried out to discover the effect on food intake, etc. of small electrolytic lesions placed by the Horsley-Clarke instrument in other areas of the hypothalamus of the albino rat, a well-localized area has been found in the lateral hypothalamus, bilateral destruction of which is followed by a complete absence of eating.
Abstract: Development of obesity in animals following destructive lesions placed in or ventrolateral to the ventromedial nucleus of the hypothalamus is a well-established fact(1, 2, 3, 4, 5, 6). This obesity...
600 citations
TL;DR: These experiments suggest that spontaneous mouse leukemia may be caused by an agent, which is transmitted from one generation to another, like that of chicken lymphomatosis.
Abstract: Summary1. Seven of 14 C3H mice inoculated when less than 12 hours old with Ak leukemic extracts developed leukemia at 8 to 11 months of age. 2. Four of 6 C3H mice inoculated. when less than 12 hours old, with cell suspensions prepared from Ak embryos. developed leukemia at 8 1/2 months of age. 3. No leukemia resulted when mice more than 12 hours old were used for inoculation. 1. These experiments suggest that spontaneous mouse leukemia may be caused by an agent, which is transmitted from one generation to another, like that of chicken lymphomatosis.
341 citations
TL;DR: Evidence is presented that the addition of a chicks'diet of mixed soybean sterols and of purified sitosterols in the presence of cottonseed oil and cholesterol causes markedly lower plasma and liver levels of cholesterol than the addition to the diet of a mixture of cholesterol andottonseed oil alone.
Abstract: SummaryEvidence is presented that the addition to the chicks'diet of mixed soybean sterols and of purified sitosterols in the presence of cottonseed oil and cholesterol causes markedly lower plasma and liver levels of cholesterol than the addition to the diet of a mixture of cholesterol and cottonseed oil alone. The possibility is discussed that one or more of the constituents of the mixed soybean sterols interferes with the absorption of cholesterol.
240 citations
TL;DR: Some of the variables involved in the production of high titer phage stocks by the agar layer method have been investigated using coli phage T4r as an example, with results ranging from 1011 to 1012 infectious particles/ml.
Abstract: SummarySome of the variables involved in the production of high titer phage stocks by the agar layer method have been investigated using coli phage T4r as an example. The significant factors have been shown to be the number of virus particles and the number of bacteria inoculated per plate, the length of incubation, the volume of soft agar in the agar layer and the volume of broth used for extraction of the virus from the agar. By an appropriate adjustment of these variable factors it is possible to obtain stocks of the various coli phages of the T series ranging from 1011 to 1012 infectious particles/ml.
214 citations
TL;DR: It was observed that equipartition of red cell and plasma unesterified cholesterol was closely approached in 4 hours and 50% equilibration took place in one hour and the possible significance of these results in relation to the nature of lipoproteins is discussed.
Abstract: SummaryPlasma and red cells containing C14-labeled cholesterol were obtained by feeding dogs with C14-acetate. The labeled blood components were separated and incubated at 37°C for several hours wi...
209 citations
TL;DR: The results of these experiments suggest that the mouse leukemia agent is transmitted from parents to their offspring, and the agent occurs most probably directly through the embryos.
Abstract: Summary1. When centrifugated extracts of Ak mouse leukemia were inoculated into 16 suckling C3H(f) infant mice less than 12 hours old, “spontaneous” leukemia developed in 8 of them at 81/2 to 11 months, and in 5 mice at 14 to 18 months of age. 2. When the centrifugated leukemic extracts were inoculated into 20 C3H(f) infant mice 3 to 6 days old, “spontaneous” leukemia developed in 10 of them, but not before they were 18 months of age. 3. Filtered (Seitz) leukemic extracts were inoculated, in 2 experiments, into 7 C3H(f) infant mice 8 days old, and 2 of them developed leukemia at 23 and 27 months respectively. In 5 additional experiments, leukemic filtrates were inoculated into 25 C3H(f) infant mice less than 12 hours old, and 7 of them developed “spontaneous” leukemia at 61/2 to 9 months of age. These results suggest that the Ak mouse leukemia agent is filterable. 4. In 5 experiments, suckling infant C3H or C3H(f) mice were inoculated with either centrifugated leukemic extracts, leukemic cell suspensions,...
176 citations
TL;DR: A simplified and improved flow rate meter is described, designed so that viscosity effects are minimized and the pressure drop through the instrument reduced to less than 3.5 cm of water at any rate of flow.
Abstract: Summary(1) A simplified and improved flow rate meter is described. The instrument is basically a rotameter, the float of which is vertically displaced in proportion to the rate of flow and its position detected electromagnetically. The rate of flow is indicated on a microammeter and a recording galvanometer. The metering chamber and float are designed so that viscosity effects are minimized and the pressure drop through the instrument reduced to less than 3.5 cm of water at any rate of flow. (2) To obtain maximum sensitivity over a given flow range, different metering chambers, with capacities ranging from 100 cc to 3 liters per minute, can be used interchangeably with one detecting unit.
142 citations
TL;DR: Material derived from spontaneous field cases of bovine papilloma of the skin was capable of causing a sarcoma-like lesion in the skin of the horse, which has some characteristics resembling equine sarcoid.
Abstract: SummaryMaterial derived from spontaneous field cases of bovine papilloma of the skin was capable of causing a sarcoma-like lesion in the skin of the horse. The tumors so induced have some characteristics resembling equine sarcoid. The ability of an oncogenic agent to induce an epithelial tumor in one animal and to cause a new growth of connective tissue cells in another species is unique.
141 citations
TL;DR: Fungicidin appears to be of value in histoplasmosis and cryptococcosis induced in mice and injected subcutaneously, its toxicity is considerably lower.
Abstract: SummaryTwo antibiotics of different chemical and biologic properties have been recovered from a soil actinomycete, Streptomyces sp.). The one is extracellular and resembles actidione. The other, designated as fungicidin, is intracellular. It is both fungistatic and fungicidal and apparently lacks antibacterial action. Its activity is not diminished by the presence of horse blood or serum. Fungicidin is distinguished from other antibiotics within our knowledge by its antimicrobial spectrum and its solubility characteristics. The approximate LD 50 for crude fungicidin administered intraperitoneally to mice is between 20 and 26 mg/kg. Injected subcutaneously, its toxicity is considerably lower. Therapeutically, fungicidin appears to be of value in histoplasmosis and cryptococcosis induced in mice.
141 citations
TL;DR: Evidence is yielded that destruction of this chemoreceptor trigger zone in cats makes the animals refractory to the emetic effect of the intravenously administered cardiac glycosides-lanatoside C, scillaren A and ouabain-in doses which are known to be effective in intact animals.
Abstract: Summary1. A hitherto unidentified structure in the medulla oblongata is described. It is an essentially non-neural zone situated between the ala cinerea and the vestibular complex and is contiguous medially with the area postrema which overlies the ala cinerea. The zone consists largely of fibroblasts and cells resembling protoplasmic astrocytes and astroblasts which have an abundance of vascular feet abutting on a dense network of blood vessels. Numerous nerve endings found in this zone are observed to connect with a loose fiber bundle which passes towards the nucleus of the fasciculus solitarius. 2. Experimental studies made with the ablation technic have yielded evidence that this structure is the anatomical framework of the medullary chemoreceptor trigger mechanism for the emetic center. Destruction of this chemoreceptor trigger zone in cats makes the animals refractory to the emetic effect of the intravenously administered cardiac glycosides-lanatoside C, scillaren A and ouabain-in doses which are kn...
138 citations
TL;DR: In addition to a strong relationship and apparent identity with West Nile virus, the Egyptian virus crosses, although to a lesser degree, with both Japanese B and St. Louis encephalitis viruses.
Abstract: Summary1. Three strains of a filterable virus closely related to West Nile have been isolated from the blood of children living on the outskirts of Cairo, Egypt. 2. The 3 strains of virus appear to be immunologically identical. 3. In addition to a strong relationship and apparent identity with West Nile virus, the Egyptian virus crosses, although to a lesser degree, with both Japanese B and St. Louis encephalitis viruses. This was found by both neutralization and complement fixation tests. 4. The virus produces a marked encephalomyelitis in monkeys inoculated intracerebrally. Lesions are found throughout the spinal cord and brain including the cerebellum. 5. Chimpanzees develop a silent infection following intracutaneous infection of the virus. This is characterized by a viremia lasting 3 days followed by the appearance of both neutralizing and complement fixing antibodies. 6. The Egyptian virus was not neutralized by human gamma globulin collected in the United States, nor by 24 different hyperimmune ser...
TL;DR: It was suggested that the palliative action of cortisone in the connectedive tissue diseases may be due to its inhibitory effect upon the synthesis of the chondroitin sulfate moiety of the connective tissue ground substance.
Abstract: Summary1. The experiments described indicated that cortisone inhibits the synthesis of chondroitin sulfate by embryonic and wound tissues maintained in vitro. Graded responses were obtained with graded concentrations of cortisone in the medium. Cortisone was shown to inhibit the synthesis of soluble organic sulfate by heart and skeletal muscle; it had no such effect upon the synthesis of soluble ester sulfate by liver tissue. 2. Concentrations of cortisone which suppressed sulfate fixation, had no apparent effect upon the initial migration of fibroblasts. Cortisone had no effect upon the pulsations of heart tissue. 3. It was suggested that the palliative action of cortisone in the connective tissue diseases may be due to its inhibitory effect upon the synthesis of the chondroitin sulfate moiety of the connective tissue ground substance.
TL;DR: It has been shown that the isolated, perfused rat liver can be maintained under conditions which permit the continuous production of bile for periods up to 25 hours, and thus maintained preserve an apparently normal histology up to the terminal phase.
Abstract: Summary(1) It has been shown that the isolated, perfused rat liver can be maintained under conditions which permit the continuous production of bile for periods up to 25 hours. (2) Livers thus maintained preserve an apparently normal histology up to the terminal phase. (3) The reticulo-endothelial cells of such perfused livers retain their ability to remove particulate matter from the perfusate stream. (4) Bromsulfalein is extracted from the perfusate by the isolated liver, and is re-excreted into the bile in high concentration and in several separable components, analogous to those found in the intact animal. (5) Data have been presented to permit a comparison of the conditions of operation and the performance of the isolated rat liver, and the liver in situ in the intact animal. (6) Details of the method of preparation, the perfusion pump, and the perfusion media have been presented, together with specific data concerning the course of typical experiments. (7) The range of applicability of the preparati...
TL;DR: The potentiating effect disappeared within 36 hours after the omission of these agents and striking potentiation of the blood pressure response to nor-epinephrine was noted within 24 hours after administration of 90-180 mg ACTH daily or 150-200 mg cortisone daily.
Abstract: Summary1. The pressor response to an intravenous infusion of 2.1-13.9 μg per minute of 1-nor-epinephrine was studied, using a constant rate infusion apparatus, in 3 patients before and during the administration of ACTH and cortisone. 2. Striking potentiation of the blood pressure response to nor-epinephrine was noted within 24 hours after administration of 90-180 mg ACTH daily or 150-200 mg cortisone daily. The potentiating effect disappeared within 36 hours after the omission of these agents.
TL;DR: In the course of preparing a 66-year—old female patient for gastric resection of a tumor later diagnosed as adenocarcinoma, difficulties were encountered in selection of compatible donors and observations suggested the presence of a new hereditary factor which is present in the red blood cells of almost all individuals tested.
Abstract: In the course of preparing a 66-year—old female patient, Mrs. D. S. J., for gastric resection of a tumor later diagnosed as adenocarcinoma, difficulties were encountered in selection of compatible donors.∗ The patient was in group O, Type MNS, presumably of the Rh genotype DCe/DCe (R1R1), Duffy and Cellano positive. The factors P, Lewis, and Lutheran could not be demonstrated in her blood. Among 3000 random group O individuals, all bloods were hemolyzed by the unheated serum or agglutinated by the inactivated serum. The hemolysin could also be demonstrated in the patient's inactivated serum by adding sensitive red cells suspended in pooled fresh group compatible unheated serum from normal individuals. The unusually high incidence of positive reactions is apparently attributable to a single antibody since all activity is removed after treatment of the serum with each of 10 different bloods.These observations suggested the presence of a new hereditary factor which is present in the red blood cells of almost...
TL;DR: In this article, it was shown that the development of esophagitis and anemia in the dog is not altered by total excision of the acid secreting portion of the stomach.
Abstract: Conclusions(1) Digestion and destruction of the living esophageal mucosa in cats and dogs can be accomplished by bile, pancreatic juice, and mixtures of the two. (2) Bleeding from esophageal erosions attending the complete diversion of bile and pancreatic juice into the esophagus in the dog causes a severe secondary anemia. (3) The development of the esophagitis and anemia in the dog is not altered by total excision of the acid secreting portion of the stomach.
TL;DR: It was shown that malonate decreased citrate formation to varying degrees in thymus, kidney, spleen and brain, but increasedcitrate formation in heart following the injection of fluoroacetate into rats.
Abstract: SummaryThe action of two or more inhibitors, each of which acts on the same metabolic sequence but upon different enzymes within a limited portion of the sequence, was defined as sequential blocking. As a model of such a system, the combined action of malonate and fluoroacetate was studied in vivo. It was shown that malonate decreased citrate formation to varying degrees in thymus, kidney, spleen and brain, but increased citrate formation in heart following the injection of fluoroacetate into rats.
TL;DR: Erythrocyte count, hematocrit determination, hemoglobin content, reticulocyte percentage, total leukocyte count, and proportion of granulocytes were determined in the blood of 2 to 3 month old virgin males and females of 18 different inbred strains.
Abstract: Summary(1) Erythrocyte count, hematocrit determination, hemoglobin content, reticulocyte percentage, total leukocyte count, and proportion of granulocytes were determined in the blood of 2 to 3 month old virgin males and females of 18 different inbred strains. The means and standard errors for each determination are given for each strain. (2) Although there was considerable overlap among the strains, it was possible by analysis of variance to show that there were significant genetic differences among the strains in factors affecting erythrocyte number (as shown both in count and hematocrit), and mean erythrocyte volume (one case only), total leukocyte count, and proportion of granulocytes. (3) Mean total leukocyte count for a strain was negatively correlated with proportion of granulocytes. (4) In this data, the observed strain differences do not appear to be related to differences in other known physiological characteristics.
TL;DR: It is suggested that post-radiation parabiosis is primarily of benefit because it accelerates recovery of myelopoiesis by the transfer of some cellular or non-cellular material from the non-irradiated partner.
Abstract: Summary and ConclusionsRats can survive an otherwise fatal dose of radiation if joined after radiation to non-irradiated litter mates. Such rats show accelerated bone marrow regeneration when compared with single controls. It is suggested that post-radiation parabiosis is primarily of benefit because it accelerates recovery of myelopoiesis by the transfer of some cellular or non-cellular material from the non-irradiated partner.
TL;DR: It is suggested that the balance between ACTH, epinephrine, insulin and cortisone secretion, because of their effect on citrate, calcium and phosphate levels, play a significant role in the maintenance of the calcium ion concentration of the plasma.
Abstract: Summary1. Epinephrine subcutaneously causes a rise in calcium, citrate and glucose levels and a fall in phosphate and potassium levels. 2. Cortisone intramuscularly causes a rise in glucose and phosphate levels and a fall in calcium and citrate levels. 3. ACTH intramuscularly causes a rise in citrate and a fall in calcium levels. 4. It is suggested that the balance between ACTH, epinephrine, insulin and cortisone secretion, because of their effect on citrate, calcium and phosphate levels, play a significant role in the maintenance of the calcium ion concentration of the plasma.
TL;DR: A simple method is presented for the efficient separation and concentration of platelets from human, dog, and guinea pig blood in quantities sufficient for transfusion and depends upon the use of Sequesterene Na2 as an anticoagulant.
Abstract: Summary(1) A simple method is presented for the efficient separation and concentration of platelets from human, dog, and guinea pig blood in quantities sufficient for transfusion. (2) This method depends upon the use of Sequesterene Na2 as an anticoagulant, which prevents the development of platelet stickiness and clumping in shed blood. (3) Platelets prepared by this method and transfused into the thrombopenic, irradiated dog remain in the circulation, reverse the coagulation defect, and prevent hemorrhage.
TL;DR: Albino rats give a demonstrable reactin of redness, swelling of loose tissue, pruritis and stupor, when injected with doses of Dextran comparable to recommended doses for humans, when administered intravenously.
Abstract: Summary and ConclusionsAlbino rats give a demonstrable reactin of redness, swelling of loose tissue, pruritis and stupor, when injected with doses of Dextran comparable to recommended doses for humans. Three different lots of Dextran gave the same reactions. Fractions of varying mean molecular weight all vave prompt reactions when administered intravenously. The delay in reaction following intraperitoneal injection may be related to the time required for the Dextran to enter the general circulation in sufficient quantity. The larger molecules pass more slowly into the circulating blood. Dextran reactions in rats following injections on subsequent days are diminished.
TL;DR: Adult mice, ordinarily insusceptible to Coxsackie virus infection, may be lethally infected if preliminarily administered cortisone and recovery of Coxsackingie virus from a human source has been accomplished in adult mice.
Abstract: Summary1. Adult mice, ordinarily insusceptible to Coxsackie virus infection, may be lethally infected if preliminarily administered cortisone. 2. Multiplication, serial passage, and specific neutralization of Coxsackie virus in adult mice have been demonstrated. 3. Recovery of Coxsackie virus from a human source has been accomplished in adult mice.
TL;DR: It is concluded that this area of increased density results from a disturbance in normal osteolytic activity.
Abstract: SummaryWhen cortisone acetate in appropriate doses is administered to growing rats, a dense zone composed of spicules of calcified cartilagenous matrix encased in bone appears at the growing ends of the bone. The width of this zone may be correlated with the duration of administration of the hormone. It is concluded that this area of increased density results from a disturbance in normal osteolytic activity.
TL;DR: It is pointed out that a close correlation exists between the mast cells and the hyaluronic acid and that cortisone acts as an inhibitory factor on these cells, just as on the other cellular constituents of the mesenchymal tissues.
Abstract: SummaryAdult rats, injected with cortisone in various doses and for a different period, constantly showed a marked reduction in the mast cell counts of the dermal, muscular and myocardial tissue, together with a strong decrease of hyaluronic acid of the connective tissue. Similar results were observed in the skin when the hormone was applied locally. It is pointed out that a close correlation exists between the mast cells and the hyaluronic acid and that cortisone acts as an inhibitory factor on these cells, just as on the other cellular constituents of the mesenchymal tissues.
TL;DR: Bilateral, symmetrical, electrolytic lesions in the hypothalamus between the suprachiasmatic and caudal ventromedian nuclei prevented the goitrogenic response of the rat to thiouracil feeding.
Abstract: SummaryBilateral, symmetrical, electrolytic lesions in the hypothalamus between the suprachiasmatic and caudal ventromedian nuclei prevented the goitrogenic response of the rat to thiouracil feeding. The iodide-concentrating capacity of the thyroid, however, increased to approximately the same extent as that of intact rats similarly treated. It appears that hypothalamic lesions of this type impair the secretion of thyrotrophin by the pituitary. It is not known whether this interference with thyrotrophin secretion is qualitative or quantitative, nor whether hypothalamic control is exerted by neural or hormonal mechanisms. The available evidence points to the secretion of a hypothalamic hormone, however.
TL;DR: In a series of patients in congestive failure, potassium depletion, either occurring spontaneously with malnutrition and gastrointestinal disorders or induced by mercurial diuresis after pre-treatment with ammonium chloride, was found to be associated with increased sensitivity to digitalis, which is suggested to results from alterations in intracellular potassium distribution.
Abstract: Summary and Conclusion1. In a series of patients in congestive failure, potassium depletion, either occurring spontaneously with malnutrition and gastrointestinal disorders or induced by mercurial diuresis after pre-treatment with ammonium chloride, was found to be associated with increased sensitivity to digitalis. 2. In 2 patients a similar decreased threshold of digitalis toxicity was observed after daily doses of 20 mg of desoxycorticosterone acetate for 4 to 10 days. 3. In one digitalized patient, digitalis toxicity was precipitated by intravenous injection of insulin and glucose, which was followed by the development of hypokalemia. 4. It is suggested that this increased myocardial sensitivity to digitalis probably results from alterations in intracellular potassium distribution since no significant changes in serum (or extracellular) potassium were observed in 8 of 10 patients.The authors gratefully acknowledge the advice and interest of Dr. Louis Leiter, and the technical assistance of Mr. George ...
TL;DR: American torula yeast, when used as the sole protein source in Vit.
Abstract: SummaryAmerican torula yeast, when used as the sole protein source in Vit. E free diets, induced dietary necrotic liver degeneration in rats in the same manner as reported for European yeasts. Other American yeasts did not produce the defect. With 30% torula yeast in the diet the incidence of liver degeneration in 15 consecutive experiments was 100%, the average survival time was 45.5 days.L-Cystine reduced the incidence of the defect considerably; however, even 1.0% did not give full protection when supplementation started at the 25th day. Five mg % vit. E prevented the defect completely.Necrosis of the liver developed very suddenly after an experimental period of 22 to S3 days and was accompanied by kidney lesions, forestomach ulcers, acute lung edema and hemorrhages in the lungs, in the lymphatic tissues and occasionally in the intestine.Acknowledgment is made to Mr. Louis E. Lowman and Mr. William Beane for technical assistance.
TL;DR: It is shown that yeast G and yeast K, which do not induce liver degeneration, exert a strong protective influence when added to diets causing the disease, due to a third unidentified factor, designated factor 3, which has been concentrated from yeast K.
Abstract: Summary(1) It is shown that yeast G (cultured, primary dried yeast) and yeast K (debittered, dried brewers yeast), which do not induce liver degeneration, exert a strong protective influence when added to diets causing the disease. It has been demonstrated by fractionation experiments that this effect is not due to vit. E or cystine, but due to a third unidentified factor, designated factor 3, which has been concentrated from yeast K. (2) The presence of factor 3 explains why dietary necrotic liver degeneration cannot be produced with American yeasts G and K. Factor 3 is water soluble, stable against acid hydrolysis, and is not identical with any one of the presently well-known vitamins.
TL;DR: Of 100 human neoplasms implanted subcutaneously in X-irradiated rats and mice as sieved or minced cell suspensions, Epidermoid carcinomas were most successfully propagated and were transplanted for 2 generations or more with evidence of active growth and vascularization.
Abstract: Summary(1) Of 100 human neoplasms implanted subcutaneously in X-irradiated rats and mice as sieved or minced cell suspensions, 33 had no mitotic cells at the end of the first generation (8 days), 34 showed cellular proliferation at the end of the first generation but could not be transferred successfully to a second, and 33 were transplanted for 2 generations or more with evidence of active growth and vascularization. (2) Epidermoid carcinomas were most successfully propagated. (3) Failures were in part due to infection and to delay between surgical removal of the tumor and its implantation in the heterologous hosts.