Showing papers in "Experimental Biology and Medicine in 1955"
TL;DR: Lactic dehydrogenase like serum glutamic oxaloacetic transaminase rises in a characteristic fashion following myocardial infarction, and is associated with a rise in serum lactic dehydrogensase activity.
Abstract: Summary and Conclusions1. Lactic dehydrogenase activity is present in the venous serum of normal human adults. Normal activity ranges from 260 to 850 units per ml with a mean value of470 ± 130 units per ml. 2. Venous whole blood hemolysates of normal adults have a lactic dehydrogenase activity varying between 16,000 to 67,000 units per ml with a mean value of 34,000 ± 12,000 units per ml. 3. Alterations in serum lactic dehydrogenase have been studied in a selected group of disease states. 4. Experimental and clinical myocardial infarction are associated with a rise in serum lactic dehydrogenase activity. 5. Lactic dehydrogenase like serum glutamic oxaloacetic transaminase rises in a characteristic fashion following myocardial infarction.
2,294 citations
TL;DR: An epidermoid carcinoma of the floor of the mouth was cultivated directly onto a glass surface in a medium consisting of 13 amino acids, 7 vitamins, glucose, salts, and 10% human serum, and all were used at concentrations permitting maximal growth of that cell.
Abstract: SummaryAn epidermoid carcinoma of the floor of the mouth was cultivated directly onto a glass surface in a medium consisting of 13 amino acids, 7 vitamins, glucose, salts, and 10% human serum. All of the defined components of this medium had previously been shown to be essential for the propagation of the HeLa cell, and all were used at concentrations permitting maximal growth of that cell. The new line (KB) has been grown continuously in this medium for 5 months, and maintains a generation time in the logarithmic phase of growth of approximately 30 hours.
453 citations
TL;DR: An accurate photometric method has been developed using a Pfalz and Bauer Fluorophotometer for measuring the lysis of suspensions of M. lysodiekticus by lysozyme and has been extended to extracts of mammalian tissues.
Abstract: SummaryAn accurate photometric method has been developed using a Pfalz and Bauer Fluorophotometer for measuring the lysis of suspensions of M. lysodiekticus by lysozyme. This method has the distinct advantages of reproducing activities in 60 seconds after addition of the enzyme. Measurement of maximal rate of lysis in the early part of the time-course of reaction decreases the possibility of interference due to synergism by proteolytic enzymes or solution of cellular material by alkali reaction. This method has been extended to extracts of mammalian tissues.
328 citations
TL;DR: 5-Hydroxytryptamine as well as histamine and heparin was demonstrated to be present in purified mast cells from the peritoneal washings of rats, matching that found in the mast cells of the subcutaneous areolar tissue of rats.
Abstract: Summary5-Hydroxytryptamine as well as histamine and heparin was demonstrated to be present in purified mast cells from the peritoneal washings of rats. The material was identified by bioassay and chromatography. The concentration of 5-hydroxytryptamine found in isolated mast cells agreed with that found by indirect means in the mast cells of the subcutaneous areolar tissue of rats. Implications of this finding are briefly discussed.
282 citations
TL;DR: The zinc-supplemented rations produced excellent growth in pigs and cured or prevented the parakeratosis syndrome.
Abstract: SummaryThe parakeratosis syndrome was produced in pigs on rations containing 34 to 44 ppm of Zn. The level of Ca and/or P affected the incidence and severity of the disease. Supplementing the diet ...
249 citations
TL;DR: Goldthioglucose injections, in the dose which produces obesity in mice, cause in these animals extensive hypothalamic damage involving the ventromedial nuclei, which is permanent in animals which in fact become obese, but are not apparent in animals unsuccessfully injected.
Abstract: SummaryGoldthioglucose injections, in the dose which produces obesity in mice, cause in these animals extensive hypothalamic damage involving the ventromedial nuclei. Such lesions are permanent in animals which in fact become obese, but are not apparent in animals unsuccessfully injected. Goldthiomalate, though as toxic as goldthioglucose, does not cause obesity; its injection does not lead to hypothalamic lesions. Implications of these findings as regards the mechanism of the regulation of food intake are discussed.
209 citations
TL;DR: The nephrotic syndrome was regularly induced in immature male rats by 12 daily injections of an aminonucleoside and skin was shown to be the major tissue reservoir for accumulation of edema fluid.
Abstract: SummaryThe nephrotic syndrome was regularly induced in immature male rats by 12 daily injections of an aminonucleoside. The essential renal lesions were thickening of the glomerular basement membranes and loss of mitochondria in renal convoluted tubular cells. Electrolyte composition of serum, ascitic fluid, muscle, entire skin, and carcass also was determined. Suitable corrections for collagen were used where applicable. Skin was shown to be the major tissue reservoir for accumulation of edema fluid.
179 citations
TL;DR: This colorimetric method for the estimation of elastase activity has the advantages of rapidity and simplicity when compared with the gravimetric and nitrogen procedures.
Abstract: SummaryA colorimetric method for the estimation of elastase activity has been presented. When dyed elastin substrate prepared from horse ligamentum nuchae is used, the pH optimum lies between 8.7 and 9.4, and the reaction velocity is linear only when less than 35% of the elastin is dissolved. When compared with the gravimetric and nitrogen procedures, this method has the advantages of rapidity and simplicity.
175 citations
TL;DR: Administration of glucagon intravenously to 7 normal subjects resulted in prompt abolition of gastric hunger contractions on each of 16 occasions, suggesting that this pattern may be a component of the normal satiety mechanism.
Abstract: SummaryAdministration of glucagon intravenously to 7 normal subjects resulted in prompt abolition of gastric hunger contractions on each of 16 occasions. This was associated with decrease in the experience of hunger and coincided with a rise in blood glucose levels and an increased peripheral capillary-venous glucose difference. Fall in blood glucose levels with decreasing capillary-venous differences was associated with a return of hunger contractions and intensification of the experience of hunger in 14 of the 16 occasions. Such a pattern may be a component of the normal satiety mechanism.
128 citations
TL;DR: It is concluded that monoamine oxidase is the major pathway of 5HTA metabolism in animals.
Abstract: SummaryOn the basis of: (1) Comparable rates of 5HTA and tyramine metabolism in tissues of 3 different animals; (2) comparable inhibition of metabolism of both amines by IIH7 a potent monoamine oxidase inhibitor; (3) a demonstration that 5HTA is metabolized by the mitochondrial portion of the liver cell; and (4) a prolongation of the effects of 5HTA in vivo following pretreatment with IIH; it is concluded that monoamine oxidase is the major pathway of 5HTA metabolism in animals.
121 citations
TL;DR: Rats irradiated with doses of X-rays in the LD50 range and subsequently injected with homologous bone marrow carrying an immunogenetic marker have persisted and functioned for as long as 147 days at the time of this communication.
Abstract: SummaryRats have been irradiated with doses of X-rays in the LD50 range and subsequently injected with homologous bone marrow carrying an immunogenetic marker. Erythrocytes carrying the label can be detected in the peripheral circulation of these animals within 2 to 3 weeks after administration of the marrow; unirradiated but marrow-injected controls do not show erythrocytes from the implant. Marrow implants have persisted and functioned for as long as 147 days at the time of this communication. The implanted marrow contributes as much as 80% of the peripheral erythrocytes.
TL;DR: Replacement of the sulfhydryl group of β-mercaptoethylamine with the isothiuronium group yields a compound (AET) with increased protective activity and greater chemical stability.
Abstract: Conclusions(a) Replacement of the sulfhydryl group of β-mercaptoethylamine with the isothiuronium group yields a compound (AET) with increased protective activity and greater chemical stability, (b) A free amino group beta or gamma to the sulfhydryl or isothiuronium group is necessary for protective activity, (c) In the aminoisothiuronium series, the carbon chain can be lengthened by one carbon atom without the loss of protective activity, (d) S,β-aminoethylisothiuronium• Br• HBr provides effective protection against radiation injury at dose levels considerably less than the dose required to produce acute toxic effects.
TL;DR: Inclusion of orotic acid in the diet of young rats results in fatty liver formation and this effect is not counteracted by lipotropic factors such as folic acid, cobalamine, methionine or choline.
Abstract: Summary1. Inclusion of orotic acid in the diet of young rats results in fatty liver formation. 2. Uracil and thymine, known to be synthesized from orotic acid, are without effect on liver fat content. 3. This effect of orotic acid is not counteracted by lipotropic factors such as folic acid, cobalamine, methionine or choline.
TL;DR: Salicylate, phenyl butazone, certain phenylbutazone derivatives and probenecid, all of which in high plasma drug concentrations increase the uric acid clearance, are demonstrated by appropriate renal clearance technics to depress the uring acid clearance at low plasma drug concentration.
Abstract: SummarySalicylate, phenylbutazone, certain phenylbutazone derivatives and probenecid, all of which in high plasma drug concentrations increase the uric acid clearance, are demonstrated by appropriate renal clearance technics to depress the uric acid clearance at low plasma drug concentrations. The significance of this paradoxical reversibility of effects is discussed in relation to controversial aspects of phenylbutazone uricosuria, the phenomenon of “compensatory” uric acid retention after discontinuance of uricosuric agents, and the nature of tubular transport mechanisms for uric acid.
TL;DR: The results suggest that regenerating adrenal cortex tissue secretes increased quantities of cortical hormones and lend strong support to the hypothesis that increased adrenal cortical function is of fundamental importance in the pathogenesis of hypertension and cardiovascular-renal disease.
Abstract: Summary and ConclusionsThis report presents a simple technic for the production of a new type of experimental hormonal hypertension with cardiovascular-renal lesions in rats sensitized by unilateral nephrectomy and salt administration. It demonstrates that such hypertension and cardiovascular-renal lesions can be produced without polydipsia and excessive sodium consumption and without alteration in the serum levels of sodium, potassium or chloride. The results suggest that regenerating adrenal cortical tissue secretes increased quantities of cortical hormones and lend strong support to the hypothesis that increased adrenal cortical function is of fundamental importance in the pathogenesis of hypertension and cardiovascular-renal disease.
TL;DR: During attempts to adapt dengue virus to rhesus monkey kidney cultures, an unidentified agent which causes formation of syncytial masses and vacuolation in such cultures was encountered and is considered to be virus-like in nature.
Abstract: SummaryDuring attempts to adapt dengue virus to rhesus monkey kidney cultures, an unidentified agent which causes formation of syncytial masses and vacuolation in such cultures was encountered. Subsequently, 3 additional agents with similar cytopathogenic effects were passed and maintained in HeLa cell cultures from uninoculated monkey kidney cultures. Renal tissue and not the medium constituents is the source of the agent. Bacteriological studies with one agent were negative. The same agent passed through a Selas filter. Accordingly it is considered to be virus-like in nature. Similar experiments were not done with 3 other agents but because of certain common characteristics are believed to be of the same nature.
TL;DR: There is a general tendency for muscle cholesterol concentration to be considerably higher in young, growing animals than in adults of the same species, which reinforces the theory that most of the cholesterol in muscle has a definite metabolic or structural function.
Abstract: Summary1. Analyses are reported for cholesterol contents of muscle and adipose tissue from beef, veal, pork, pig, mutton, lamb, rabbit, chicken and man. It is shown that a large proportion of the cholesterol in muscle is not attributable to residual adipose tissue or any tissue of similar composition. 2. Concentration of cholesterol in muscle, apart from associated adipose tissue, is of the order of 40 to 50 mg per 100 g in the adult mammals studied and in the dark meat of chickens. Higher values were found in two elderly human beings. The corresponding cholesterol concentration in the white meat of chickens is of the order of 30 mg per 100 g. 3. There is a general tendency for muscle cholesterol concentration to be considerably higher in young, growing animals than in adults of the same species. This reinforces the theory that most of the cholesterol in muscle has a definite metabolic or structural function.
TL;DR: It is concluded that in Xenopus the males are the homozygous sex and that phenotypic sex reversal does not affect the male genetic constitution.
Abstract: SummaryXenopus larvae of male genetic sex develop into phenotypic females, if raised in weak solutions of estradiol (25 to 1000 μg/1). Such feminized males, if bred to normal males, produce uniformly male offspring. It is concluded that in Xenopus the males are the homozygous sex and that phenotypic sex reversal does not affect the male genetic constitution. The practicability of breeding entirely homozygous male and female laboratory stock of Xenopus is pointed out.
TL;DR: A new synthetic medium for animal cells in tissue culture has been devised that is considerably more adequate than solution No. 703, and supports these and certain other types of cells at a slow rate of multiplication for indefinite periods.
Abstract: Summary1. A new synthetic (chemically-defined) medium for animal cells in tissue culture has been devised that is considerably more adequate than solution No. 703, reported earlier. 2. The new medi...
TL;DR: In a female rat with 2 bipolar bilateral electrodes in the lateral hypothalamus at the level of the lower dorsomedian nucleus, violent drinking activity could be stimulated by passing a 60 cycle, 2 msec pulse across the electrodes by RF activation of a subcutaneously buried pickup unit.
Abstract: SummaryIn a female rat with 2 bipolar bilateral electrodes in the lateral hypothalamus at the level of the lower dorsomedian nucleus, violent drinking activity could be stimulated by passing a 60 cycle, 2 msec. D.C. pulse across the electrodes by RF activation of a subcutaneously buried pickup unit. During the period of maximal response, the rat drank in excess of 400 ml tap water daily while chronically stimulated. By the fifth day the animal had lost its responsiveness to stimulation. The drinking behaviour was not secondary to diuresis but was an immediate and direct response to hypothalamic stimulation.
TL;DR: Prolonged transintestinal intubation with polyvinyl tubing (2.1 mm OD) has been well tolerated, and sampling has been effected under conditions which closely approach the physiological state.
Abstract: SummaryA technic is described for sampling the contents of the intestinal tract in human subjects repeatedly and at various intestinal levels over a 1-2 week intubation period. Prolonged transintes...
TL;DR: Production of a mucin clot in the medium of cultures of fibroblasts from various tissues (or even a single roller tube culture) can be used as a method for preliminary orientation in determining differentiation of various types of fibROblasts, and for studying factors influencing such differentiation.
Abstract: Summary1. Cultures of human synovia and rat subcutaneum have continued to produce, over a period of months, substances forming a characteristic mucin clot. Mucin clots have also been produced in cu...
TL;DR: A method is described for detection of chromosomal sex from a smear of oral mucosa cells with the advantage of ease in securing suitable cells, rapidity in preparation and simplicity of interpretation.
Abstract: SummaryA method is described for detection of chromosomal sex from a smear of oral mucosa cells. In 50 females 20-79% of the cells had sex chromatin bodies in the nuclei. The occurrence of similar masses in oral smears from 50 males ranged from 0-4%. The method offers the advantage of ease in securing suitable cells, rapidity in preparation and simplicity of interpretation.
TL;DR: It is suggested that increased rate of formation of phospholipides of liver and plasma need not necessarily be a specific effect of growth hormone but a change in this parameter of metabolism subsidiary to enhanced mobilization of endogenous fat.
Abstract: Summary1. A study was made of the effects of a single injection of anterior pituitary purified growth hormone on distribution of lipides and turnover of phospholipides in plasma, liver and aorta a few hours after administration in intact rabbits. 2. Plasma glucose and liver glycogen concentration, and total liver weight were moderately, but significantly, increased in animals which received growth hormone. 3. Contents of all lipide fractions of plasma and entire liver were significantly increased in experimental animals. In the aorta, the only change was a significantly decreased neutral fat content. 4. Liver total lipide content was increased 64%, plasma total lipide was increased 85%, and aorta total lipide was decreased 25%. The relative contribution of each lipide fraction to percentage increased or decreased total lipide determined in these tissues was as follows: in liver, neutral fat contributed 47%, phospholipide 15%, and free and ester cholesterol 1.5% each; in plasma, neutral fat contributed 53%...
TL;DR: Two human transfusions of frozen and thawed whole blood containing erythrocytes tagged with Cr51 demonstrate the ability of red cells to survive in vivo after freezing in liquid nitrogen at −195.8°C.
Abstract: Summary1. In accordance with previously derived criteria for non-traumatic rapid freezing, very small (.45-.9 mm) droplets of citrated whole blood with added dextrose are sprayed onto liquid nitrogen. The frozen blood is reconstituted in warm saline. 2. Two human transfusions of frozen and thawed whole blood containing erythrocytes tagged with Cr51 demonstrate the ability of red cells to survive in vivo after freezing in liquid nitrogen at −195.8°C.
TL;DR: Of three antibacterial substances tested, only neomycin markedly reduced the ammonia content of portal venous blood from the colon, which was the principal source of ammonia in portal blood.
Abstract: Summary1. Five mongrel dogs were fed raw horsemeat 3 days and on fourth day, a laparotomy was performed. Samples of venous blood from various segments of gastrointestinal tract were drawn for determinations of ammonia content. The same animals, similarly prepared, were used after an interval of 2 to 3 weeks to test the effect of orally administered antibacterial agents on the level of ammonia in venous blood obtained from various portions of the gastrointestinal tract. For this purpose, neomycin, sulfasuxidine or achromycin were administered preoperatively by mouth for varying periods. 2. The colon was the principal source of ammonia in portal blood. Of three antibacterial substances tested, only neomycin markedly reduced the ammonia content of portal venous blood from the colon.
TL;DR: β-amino propionitrile will produce all the changes which have been described in rats fed 50% Lathyrus odoratus pea meal and none of the supplements fed with BAPN inhibited the development of skeletal deformities.
Abstract: Summaryβ-amino propionitrile will produce all the changes which have been described in rats fed 50% Lathyrus odoratus pea meal. None of the supplements fed with BAPN inhibited the development of skeletal deformities. Substitution of a methyl or acetyl into the amino group or a substitution of hydroxy for the amino group in BAPN results in a loss of biologic activity. Unlike BAPN which principally modifies bone development and produces marked skeletal deformity, Bis-β-(cyanoethyl)-amine exerts an early and pronounced influence on the central nervous system and subsequently produces lesser skeletal alterations.
TL;DR: Serum of carbon tetra-chloride-treated rats contained more non-esterified higher fatty acids than that of normal rats, offering further evidence for the postulation that the lowering of the azorubin-binding capacity of serum albumin is caused by increased concentrations of firmly boundHigher fatty acids.
Abstract: Summary 1. Available methods for the determination of the “free,” i.e. non-esterified, higher fatty acid fraction in serum were modified. These acids are firmly bound to albumin. Slightly less than one mole of them was found per mole albumin in normal rat, rabbit and bovine serum. 2. Serum of carbon tetra-chloride-treated rats contained more non-esterified higher fatty acids (1.30 moles per mole albumin) than that of normal rats (0.85 mole per mole albumin). The difference was statistically significant. 3. The results are considered indicative of the impaired liver function in the injured rats. They offer further evidence for the postulation that the lowering of the azorubin-binding capacity of serum albumin is caused by increased concentrations of firmly bound higher fatty acids.
TL;DR: Daily rhythms were studied in I mice of several age groups under standardized experimental circumstances and 24-hour periodicities are noted for the susceptibility of I mice to audiogenic Convulsions and for their ability to recover from convulsions.
Abstract: SummaryDaily rhythms were studied in I mice of several age groups under standardized experimental circumstances. The rhythms in eosinophil count and in rectal temperature are described for this stock. Moreover, 24-hour periodicities are noted for the susceptibility of I mice to audiogenic convulsions and for their ability to recover from convulsions. The magnitude of these differences was large and was statistically significant. In one group of young animals the convulsive risk was 11% by day and 63% by night and in another, 0% by day and 85% by night. Changes with age in several of the variables studied are also noted.
TL;DR: Samples of striated muscle and liver from fasted mice with the hereditary obese-hyperglycemic syndrome were analyzed for water, fat, potassium, sodium, and chloride and some degree of intracellular dehydration and a greater degree of extracellular dehydration was observed.
Abstract: Summary1. Samples of striated muscle and liver from fasted mice with the hereditary obese-hyperglycemic syndrome were analyzed for water, fat, potassium, sodium, and chloride. 2. Some degree of intracellular dehydration and a greater degree of extracellular dehydration was observed without change in concentration of intracellular potassium.