bluuebunny/crossref_metadata_2025_split huggingface dataset:
OSMOTIC ACTIVITY OF LIVER CELLS AND MELTING POINT OF LIVER
Authors: Opie Eugene L. 
Published: June 2004

Depression of the melting point of liver tissue rapidly frozen by liquid nitrogen during life provides a means by which the molecular concentration within liver cells may be compared with that of solutions of sodium chloride or of blood or of blood serum.
The rising temperature of frozen blood of guinea pig under the conditions of these experiments is retarded when melting occurs, pursues when plotted a prolonged linear course, and finally rises precipitously at –0.54°C. when melting is complete. With the melting of blood serum of guinea pig and of blood of cat and of rat, the temperature takes approximately the same course. The temperature changes are nearly the same as those of a frozen solution of sodium chloride isotonic with blood serum.
The temperature changes of frozen liver assumes when plotted a linear course at about –1.1°C., increases at intervals with step-like progress and finally rises precipitiously at –0.76°C. The temperature changes in melting liver of cat and of rat are similar. The melting of liver begins at a level which approximates that of a solution of sodium chloride isotonic with it.
The step-like course of temperature changes which occur during the melting of frozen liver are best explained by the assumption that the cells contain substances which successively and temporarily retard the rise of temperature.
THE EFFECT OF ADRENAL STEROIDS, CORTICOTROPIN, AND GROWTH HORMONE ON RESISTANCE TO EXPERIMENTAL INFECTIONS
Authors: Kass Edward H. , Lundgren Marguerite M. , Finland Maxwell 
Published: June 2004

Cortisone acetate, hydrocortisone, and hydrocortisone acetate depress the resistance of mice to pneumococcal and influenza viral infections, although hydrocortisone acetate is somewhat less effective than the free alcohol, when given subcutaneously.
Pituitary adrenocorticotropin, even in highly purified form and in oil and beeswax, does not significantly alter the resistance of mice to these experimental infections, even when given in doses which may cause profound eosinopenia, lymphopenia, and weight loss, and which are at the limit of tolerance of the animals.
Corticosterone depresses resistance to pneumococcal infections significantly, but fails to alter resistance to influenza viral infections. The findings suggest that murine adrenals may produce one of the known adrenal steroids such as corticosterone along with another steroid, or may produce a steroid other than cortisone, hydrocortisone, or corticosterone.
When resistance is decreased by adrenal steroids, survival time is invariably shortened, and the effect of the steroid hormones is frequently demonstrable within the 1st day after infection with pneumococci, making it unlikely that the depression of resistance that is seen is primarily due to depression of antibody formation.
A single dose of 5 mg. of cortisone may cause depression of resistance and may decrease the survival time for 3 to 6 days afterward.
Growth hormone (somatotropic hormone) in highly purified form, and in the doses used, did not overcome the weight loss induced by cortisone, but the animals treated with growth hormone and cortisone regained their lost weight more rapidly than those receiving cortisone alone. Growth hormone alone caused a slight increase in the rate of gain in weight over controls.
Growth hormone alone did not increase resistance to infection, and did not increase the survival time, in mice infected with either pneumococci or influenza virus. Growth hormone in various dosages failed to overcome the effect of cortisone in depressing resistance to these infections.
Cortisone, hydrocortisone, corticosterone, and corticotropin did not alter significantly the titers of influenza virus attained in the murine lungs during the first 2 days after infection, but cortisone and hydrocortisone markedly delayed the rate at which virus titers declined during the subsequent 6 days. Corticosterone and corticotropin delayed the rate at which the titers declined but slightly, and growth hormone had no apparent effect, as compared with controls. Growth hormone did not overcome the effect of cortisone and hydrocortisone on viral titers. No detectable antibody was found as late as 6 days after infection, in controls or in hormone-treated animals.
SYNTHESIS OF ALL PLASMA PROTEIN FRACTIONS EXCEPT GAMMA GLOBULINS BY THE LIVER
Authors: Miller Leon L. , Bale William F. 
Published: June 2004

Lysine-ϵ-C14-labeled plasma proteins produced by the normal rat and the isolated perfused rat liver have been fractionated by preparative zone electrophoresis. The isolated perfused liver incorporates lysine-ϵ-C14 into the plasma albumin, alpha globulin, and beta globulin (including fibrinogen) fractions. No significant C14 incorporation into the trichloracetic acid-precipitable proteins of the gamma globulin fraction was observed.
Presumptive evidence indicates that the alpha globulins turn over more rapidly than any other major plasma protein fraction.
The increased production of gamma globulins in liver disease is discussed.
PLASMA AND TISSUE PROTEINS PRODUCED BY NON-HEPATIC RAT ORGANS AS STUDIED WITH LYSINE-ϵ-C14
Authors: Miller Leon L. , Bly C. G. , Bale William F. 
Published: June 2004

The non-hepatic tissues in a perfused "carcass" (caudal half of the rat) maintain some physiological functions for as long as 5 to 6 hours of perfusion, including good clearance of lysine-ϵ-C14 and glucose from the perfusate, and synthesis of both tissue and plasma proteins.
The perfused "carcass" tissues incorporate only small amounts of lysine-ϵ-C14 into the plasma proteins to an extent not markedly affected by the presence of the gastrointestinal tract, pancreas, spleen, or kidneys. This activity is found only in the globulin fraction obtained by sodium sulfate fractionation. No significant activity was detected in the plasma fibrinogen or albumin fractions.
C14-labeled plasma proteins obtained from the eviscerated surviving rat 6 hours after intravenous lysine-ϵ-C14 have been separated by zone electrophoresis. The gamma globulins contain most of the C14 activity, with small but measurable activity in the beta and alpha globulins, and no activity in the albumin fraction.
PLAQUE FORMATION AND ISOLATION OF PURE LINES WITH POLIOMYELITIS VIRUSES
Authors: Dulbecco R. , Vogt Marguerite 
Published: June 2004

Plaques have been produced with the three types of poliomyelitis viruses on monolayer tissue cultures of monkey kidney and monkey testis. The number of plaques was proportional to the concentration of the virus. Each plaque originates, therefore, from a single virus particle, defined as the virus unit that is unseparable by dilution. The plaques are due to the specific action of the virus since they are suppressed by type-specific antiserum.
Pure virus lines were established by isolating the virus population produced in single plaques. These derived virus lines had the same morphological, serological, and pathogenic properties as the parent strain.
High titer virus stocks, with titers up to 7 x 108 plaque-forming particles per ml., were obtained.
THE BINDING OF PENICILLIN IN RELATION TO ITS CYTOTOXIC ACTION
Authors: Eagle Harry 
Published: June 2004

1. Bacteria exposed to C14- or S35-labelled penicillin bound and concentrated the antibiotic. The amount bound from low concentrations (0.001 to 0.01 µg. per ml.) was related to the penicillin sensitivity of the strain; and highly sensitive organisms such as Streptococcus pyogenes concentrated the antibiotic as much as 200-fold. The material bound by highly sensitive strains from these low concentrations of penicillin was removed to only a minor extent by washing. Penicillin inactivated with penicillinase, by hot H2SO4 or by cold HCl was not similarly concentrated.
2. Despite wide differences in their sensitivity to penicillin, at equieffective (LD99.9) levels, four of the five strains here studied had bound comparable amounts of antibiotic. That lethal intracellular concentration averaged 1.7 to 4 µg. per gm., and 1600 to 3300 molecules per cell.
3. Bacteria in the logarithmic phase of growth, "resting" organisms, and cell-free sonic extracts, had roughly the same reactivity with penicillin. The differences in the amount of penicillin bound by bacteria of varying sensitivity therefore do not rest on differences in the permeability of the cell.
4. Escherichia coli (K12)-inactivated penicillin within the cell; and that inactivation adequately explains its low binding affinity, and its relative resistance. The other species here studied inactivated the diffusible cellular penicillin to only a minor degree, and not enough to explain the differences in their penicillin-sensitivity. The working hypothesis is suggested that their varying sensitivity is instead determined by differences in the reactivity of vital cell components with the antibiotic.
5. At high concentrations of antibiotic (1 to 1000 µg. per ml.), there was non-specific binding by all the cell strains and cell extracts here studied, unrelated to their sensitivity, and masking the specific differences in reactivity noted at low concentrations. At these high levels, penicilloic acid was bound to the same degree as the active antibiotic.
THE EFFECT OF UNDERNUTRITION ON CHOLESTEROL ATHEROSCLEROSIS IN THE RABBIT
Authors: McMillan Gardner C. , Whiteside J. H. , Duff G. Lyman 
Published: June 2004

Experiments were done to determine whether undernutrition with consequent loss of weight or failure to gain weight inhibited the development or promoted the regression of the aortic lesions of experimental cholesterol atherosclerosis in the rabbit. The experiments were conducted in such a way as to determine whether undernourished and adequately nourished rabbits fed the same daily doses of cholesterol would manifest different degrees of atherosclerosis at the end of an experiment.
Different experiments tested the effect of undernutrition in young, growing animals that failed to gain weight normally (Experiments 1 and 2); in young rabbits subjected to marked undernutrition both before and during cholesterol feeding (Experiment 3); in fully grown, mature rabbits that lost weight during undernutrition (Experiment 4); and in rabbits that had completed a period of cholesterol feeding before caloric restriction was begun (Experiment 5).
In every experiment it was observed that, if two groups of rabbits were fed cholesterol, one group being subjected to caloric restriction while the other received an adequate diet, no difference in aortic atherosclerosis was observed between the two groups at the termination of the experiment. Furthermore, no obvious effect of undernutrition on the regression of atherosclerotic lesions was observed in the rabbit.
At the same time, undernutrition was found to promote hypercholesterolemia in the rabbit fed cholesterol. The possible significance of this result was discussed.
GLYCOGEN, AN IMMUNOLOGICALLY SPECIFIC POLYSACCHARIDE
Authors: Heidelberger Michael , Aisenberg Alan C. , Hassid William Z. ,   With the Technical Assistance of Arnold Powell
Published: June 2004

Glycogens from various animal and vegetable sources precipitate antipneumococcal horse sera of Types II, VII, IX, XII, XX, and XXII.
Fractionated glycogen and glycogen recovered after reprecipitation, acetylation, and deacetylation precipitate the antisera, but glycogen degraded by saliva does not.
A fraction of the antibody is precipitated in the antisera by glycogen. Possible chemical relationships accounting for these instances of cross-precipitation are discussed in terms of the structures of glycogen and the type-specific polysaccharides of pneumococcus and the quantitative theory of specific precipitation.
Amylopectin also gives cross-reactions of smaller magnitude. Quantitative data on these are withheld until irregularities have been eliminated.
VIREMIA IN HUMAN POLIOMYELITIS
Authors: Horstmann Dorothy M. , McCollum Robert W. , Mascola Anne D. 
Published: June 2004

Poliomyelitis virus was isolated from the blood of 6 of 33 individuals infected with a Type 1 strain. Of the 27 negative for viremia, 18 already had Type 1 antibodies.
Type 1 virus was isolated from the throat swabs of all 6 who had viremia, and from the 5 rectal swabs tested. These specimens were all collected at the same time as the positive blood specimens.
The clinical circumstances under which viremia was detected included the minor illness, the asymptomatic infection, and one instance in which the virus was isolated several days before the onset of a mild non-paralytic attack.
In one instance, virus was isolated from a blood specimen which also contained Type 1 antibodies.
The possible role of viremia in the pathogenesis of poliomyelitis is discussed.
SELECTIVE NECROSIS OF CARDIAC AND SKELETAL MUSCLE INDUCED EXPERIMENTALLY BY MEANS OF PROTEOLYTIC ENZYME SOLUTIONS GIVEN INTRAVENOUSLY
Authors: Kellner Aaron , Robertson Theodore 
Published: June 2004

Focal necrosis of cardiac and skeletal muscle was produced regularly in rabbits by means of a single intravenous or intra-arterial injection of a solution of crude papain. Similar lesions were produced in rats and mice injected with this material. The intravenous injection of solutions of ficin, trypsin, and streptokinase also resulted in comparable lesions of cardiac and skeletal muscle in rabbits.
The lesions in the myocardium became apparent within 6 hours after injection of the enzyme; they consisted essentially of focal degeneration and necrosis of the sarcoplasm and myofibrils within a segment of muscle fiber. An inflammatory reaction consisting of a small number of polymorphonuclear leukocytes and considerable numbers of mononuclear cells, and often multi-nucleated giant cells, was present within the lesions. In some instances severely damaged fibers were replaced by fibrous tissue and in others proliferation of muscle cell nuclei and restitution of the fiber appeared to take place. Similar changes of a lesser degree were also observed in skeletal muscle.
The findings are discussed in connection with the pathogenesis of the anatomical lesions of rheumatic fever, periarteritis nodosa, and other hypersensitivity states.
STUDIES ON SUSCEPTIBILITY TO INFECTION FOLLOWING IONIZING RADIATION
Authors: Hammond Carolyn W. , Colling Margaret , Cooper Dorothy B. , Miller C. Phillip 
Published: June 2004

Mice were inoculated by mouth at different times (2 hours, 5 days, and 11 days) after a single exposure to 550 r total body x-irradiation. The inocula contained approximately 107 Pseudomonas aeruginosa which was found to be quite harmless for unirradiated mice.
Comparison of the cumulative mortality curves and of the incidence of Pseudomonas bacteremia showed their susceptibility to infection by this route to be greatest on the 11th day, somewhat less on the 5th day post irradiation, and least of all directly after irradiation. Since damage to the intestinal mucosa has been found to be maximal within the first few hours after exposure to doses of x-irradiation in this range, it seems reasonable to conclude that the increased susceptibility is not due to increased permeability of the mucosa of the gut, but to impairment of the animal's natural defenses against infection.
STUDIES ON THE FACTORS ESSENTIAL TO THE INITIATION AND MAINTENANCE OF MULTIPLICATION OF PSITTACOSIS VIRUS (6BC STRAIN) IN DEFICIENT CELLS IN TISSUE CULTURE
Authors: Hare John D. , Morgan Herbert R. 
Published: June 2004

The growth of psittacosis virus (6BC) was studied in cultures of minced whole chick embryo tissue maintained in either Hanks-Simms solution or Hanks's balanced salt solution (BSS), and in neither medium could sustained, long-term virus growth take place. Addition of beef embryo extract (BEE) to cultures at a time when virus multiplication was declining reversed this general trend and resulted in greater virus growth. This virus-stimulating action of BEE was only partially diminished by colchicine, a mitotic inhibitor, indicating that the action of BEE was not due entirely to the development of a larger population of cells as a result of its enhancement of cell proliferation.
Chick embryo tissue cultivated for 13 days in BSS prior to infection lost its ability to support the growth of psittacosis virus, but this capacity could be restored by the addition of BEE, alone or with colchicine, at the time of infection. A significant amount of virus was adsorbed to tissue in BSS alone, indicating that the failure of virus to grow in depleted tissue maintained only in BSS after infection was not due entirely to failure of virus to attach to and invade the cells.
It was found that an ultrafiltrate and a dialysate of BEE contained the major part of the stimulating capacity of the whole extract, indicating that the active materials were substances of low molecular weights. Autoclaved lactalbumin hydrolysate was an active stimulator, suggesting that the materials responsible for its activity were relatively heat-stable.
Since a chemically defined medium (Parker 199) was equally effective in stimulating viral growth, it should be possible eventually to define the chemical nature of the virus stimulators.
The implications of the findings are discussed with special reference to their application in the study of tissue tropisms and of latency in viral infections of cells.
MYOCARDIAL NECROSIS PRODUCED IN ANIMALS BY MEANS OF CRYSTALLINE STREPTOCOCCAL PROTEINASE
Authors: Kellner Aaron , Robertson Theodore 
Published: June 2004

Focal myocardial necrosis that was often extensive was found in a high percentage of rabbits, guinea pigs, and mice given a single intravenous injection of crystalline streptococcal proteinase.
The findings are discussed in relation to their possible implications for the pathogenesis of the cardiac lesions of rheumatic fever.
CELLULAR MECHANISMS OF PROTEIN METABOLISM IN THE NEPHRON
Authors: Oliver Jean , MacDowell Muriel , Lee Yin Chen 
Published: June 2004

When proteins pass the glomerular filter they are in part directly absorbed by the epithelial cells of the proximal convolution of the nephron with no apparent alteration of the cytological pattern. If the capacity of the tubule cells to thus absorb protein from the tubule fluid is exceeded either by the amount or the nature of the protein the accessory mechanism of droplet formation occurs. This accessory mechanism is an intracellular process in which cytoplasmic elements, the mitochondria with their enzymes, and the absorbed protein combine to form droplets. As the droplets form and then disappear from the renal cells their evolution presents a constantly changing picture depending on the varying nature of their protein and cytoplasmic content.
The droplet is therefore not a cytological structure of fixed characteristics (hyaline droplet) but a locus of metabolic activity and varied structural aspect.
CELLULAR MECHANISMS OF PROTEIN METABOLISM IN THE NEPHRON
Authors: Lee Yin Chen 
Published: June 2004

1. The cells of the proximal convolutions of the rat can be filled with fine droplets by the administration of certain amino acids in non-toxic dosage.
2. These minute droplets resemble in their Gram positivity and in their phospholipid and PNA content on biochemical analysis (3) the larger droplets that form in the cells of the proximal convolution during the absorption of certain proteins.
3. The positive or negative reaction to 3 specific histochemical procedures of the fine droplets forming after administration of 7 amino acids gave such a high positive correlation with theoretical assumption as to warrant the following inferences: (a) that the methods are specific under the conditions of the experiment; (b) that the droplets contain a higher concentration of the administered amino acid than the general cytoplasm of the cells which contain them.
4. The mitochondrial rodlets of epithelium of the proximal convolution contain sulfhydryl in high concentration, a finding which correlates well with their enzymatic activity.
CELLULAR MECHANISMS OF PROTEIN METABOLISM IN THE NEPHRON
Authors: Kretchmer N. , Cherot Francis J. 
Published: June 2004

Parenteral injection of amino acids resulted in the formation of Gram-positive droplets in the cytoplasm of the proximal convoluted tubule cells of the kidney of the rat within 15 minutes after intravenous administration.
At this time the free alpha amino nitrogen in the cortex of the kidney had increased 2-fold. At the end of 1 hour this level was still somewhat higher than that of the control animals.
The administration of increasing amounts of the amino acid disclosed the existence of a maximal concentration level in the renal cortex. When it was reached droplets appeared.
Fractionation of the cells 15 minutes after the injection of lysine resulted in the recovery of free amino acid in the supernatant fluid but 1 hour after the injection lysine was contained within the particulate protein of the fractions which contain droplets. The increase in lysine was of the order of 2- 3-fold.
It is concluded that the mitochondria-droplet complex is a locus of amino acid concentration and metabolism within the cytoplasm of the renal cell.
A method is described for the determination of lysine in micro quantities.
Combination of Isoflurane and Caspase Inhibition Reduces Cerebral Injury in Rats Subjected to Focal Cerebral Ischemia
Authors: Inoue Satoki , Drummond John C. , Davis Daniel P. , Cole Daniel J. , Patel Piyush M. 
Published: June 2004

Background
Recent data indicate that the neuroprotective efficacy of isoflurane is not sustained. Delayed neuronal death, mediated in part by apoptosis, contributes to the gradual increase in the size of the infarction. These data suggest that isoflurane may not be able to inhibit delayed neuronal death. The prevention of apoptosis by a caspase inhibitor might provide neuroprotection in addition to that provided by isoflurane. The current study was conducted to determine whether isoflurane-mediated neuroprotection can be made more durable with the administration of z-VAD-fmk, a nonspecific caspase inhibitor.

Methods
Fasted Wister rats were allocated to awake-zVAD, awake-vehicle, isoflurane-zVAD, or isoflurane-vehicle groups (n = 16/group). Animals were subjected to focal ischemia for 60 min by filament occlusion of the middle cerebral artery. In the awake groups, isoflurane was discontinued after occlusion of the middle cerebral artery. In the isoflurane groups, isoflurane anesthesia was maintained at 1.5 minimum alveolar concentration during occlusion of the middle cerebral artery. Before and after ischemia, daily injections of z-VAD-fmk or vehicle were administered into the lateral cerebral ventricle for 14 days. Neurologic assessment was performed 14 days after ischemia. The volume of cerebral infarction and the number of intact neurons in the periinfarct cortex were determined by image analysis of hematoxylin and eosin-stained coronal brain sections.

Results
Infarction volume was less in the isoflurane-zVAD group (23 +/- 11 mm, mean +/- SD) than in isoflurane-vehicle, awake-vehicle, and awake-zVAD groups (82 +/- 31, 86 +/- 31, and 59 +/- 25 mm, respectively; P < 0.05). In comparison with the awake-vehicle and isoflurane-vehicle groups, the administration of z-VAD-fmk significantly decreased infarction volume (P < 0.05). The infarction volume between the awake-vehicle and isoflurane-vehicle groups was not different. The number of intact neurons within the periinfarct cortex was significantly less in the awake-vehicle group than in the other three groups (P < 0.05). The isoflurane-zVAD group demonstrated better neurologic function than the awake-vehicle group (P < 0.05).

Conclusion
These findings are consistent with the premise that ongoing delayed neuronal death, in part mediated by apoptosis, contributes to the progression of cerebral infarction during the recovery period, and its inhibition can provide sustained neuroprotection.