bluuebunny/crossref_metadata_2025 huggingface dataset:
EXPERIMENTS ON THE RÔLE OF THE CHICKEN MITE, DERMANYSSUS GALLINAE, AND THE MOSQUITO IN THE EPIDEMIOLOGY OF ST. LOUIS ENCEPHALITIS
Authors: Smith Margaret G. , Blattner Russell J. , Heys Florence M. , Miller Albert
Published: June 2004

The present experimental results concern primarily the question, whether or not mosquitoes feeding on chickens having viremia, as a result of the bite of infected mites, can acquire the virus of St. Louis encephalitis and whether or not mosquitoes thus infected, can transmit the virus to chickens and hamsters.

During the course of the investigation, 7 species of mosquitoes of 3 genera were infected with the virus in one or two or all of three ways: by feeding on a suspension of infected mouse brain tissue, by feeding on chickens in which viremia had been produced by subcutaneous inoculation of virus, and by feeding on chickens having viremia as a result of the bite of infected mites. These mosquitoes transmitted the virus to chickens at periods varying from 5 to 33 days after the infective meal.

The virus of St. Louis encephalitis was transmitted to hamsters by Culex pipiens at periods varying from 4 to 27 days after feeding on chickens having viremia as a result of the bite of infected mites. While viremia was demonstrated readily in hamsters, signs of encephalitis did not develop.

In all transmission experiments the method of chorioallantoic passage proved necessary for the demonstration of viremia.

A concept of the epidemiology of St. Louis encephalitis is presented: two blood-sucking vectors may be involved, one an arachnid, the mite, maintaining the virus in nature by transovarial passage, and the other, an insect, the mosquito, which carries the infection from birds to other vertebrates including man.
EFFECT OF ENZYME INHIBITORS AND ACTIVATORS ON THE MULTIPLICATION OF TYPHUS RICKETTSIAE
Authors: Greiff Donald , Pinkerton Henry
Published: June 2004

A technique is described for measuring the oxygen uptake of embryonate eggs. Statistical analysis has shown that the method is reliable and accurate. Determinations were made on groups of 15 to 20 eggs, in order to average out individual biological variations. Reduction of the CO2 tension and relative humidity to approximately zero previous to analysis has been found to be desirable. The oxygen consumption of normal and typhus-infected eggs, untreated and treated with agents previously found to inhibit or enhance rickettsial growth has been studied.

Rickettsial infection caused a slight but significant increase in the rate of oxygen consumption on the 4th day after inoculation, followed by a rapid drop in the rate as the infection developed. The evidence suggests that low concentrations of rickettsial toxins may stimulate respiration, while higher concentrations depress respiration and lead eventually to embryonic death.

PABA, which is rickettsiostatic, markedly increased the oxygen uptake of normal eggs, the effect appearing 4 days after injection and lasting for about 4 days. Thereafter, the rate fell below that of the untreated eggs. In typhus-infected eggs, PABA had similar effects, but the oxygen consumption reached much higher levels. A possible explanation of this fact is suggested. MABA and OABA, which are not rickettsiostatic, did not increase oxygen uptake; in fact they depressed cellular respiration moderately, OABA being more active in this way than MABA. These two compounds may compete with PABA for a position in some respiratory enzyme system.

Potassium cyanide, which enhances rickettsial growth, caused, in concentrations not lethal to the embryos, a moderate drop in the oxygen consumption of normal eggs, the effect starting almost immediately after injection and lasting usually for 9 days. In infected eggs, its effect was more striking. It is probable that rickettsial toxins and KCN act synergistically to depress cellular respiration.

When PABA and KCN were injected simultaneously, the stimulating effect of PABA on respiration predominated. The resulting level of oxygen consumption, though lower than that resulting from PABA alone, was still high enough to inhibit rickettsial growth.

As far as our results go, they support the hypothesis that, within certain limits, rickettsial growth is inversely proportional to the respiratory rate of the host cells, regardless of the factors which determine that rate. It is not yet clear that PABA owes its rickettsiostatic action to its ability to increase cellular respiration, but this assumption seems reasonable as a working hypothesis. The respiratory mechanism in which PABA participates is not as yet known.

Although PABA forms part of the folic acid molecule, folic acid itself, in concentrations corresponding to effective doses of PABA, did not increase cellular respiration or show rickettsiostatic action.
THE PROTEINS IN UNHEATED CULTURE FILTRATES OF HUMAN TUBERCLE BACILLI
Authors: McCarter Janet R. , Bevilacqua Ellen B.
Published: June 2004

1. Only two serologically different proteins were found in the unheated culture filtrates of both virulent and slightly virulent tubercle bacilli. One of them was the protein which had a sedimentation constant of 3.4 S, and the other was in filtrate fractions with a constant of 2 S.

2. That these proteins were distinct was demonstrated by three methods: quantitative precipitin and precipitin absorption tests with rabbit antisera, skin tests in guinea pigs actively sensitized with the culture filtrate fractions, and skin tests in passively sensitized guinea pigs.

3. A third antigen of unknown nature was found by means of the precipitin tests, but only in certain fractions from the virulent culture filtrate.

4. The protein with the constant of 3.4 S could not be demonstrated serologically in an O.T. made from the same culture filtrate as the unheated preparation from the virulent organism.
IMMUNOCHEMICAL STUDIES ON BLOOD GROUPS
Authors: Kabat Elvin A. , Bendich Aaron , Bezer Ada E. , Knaub Vesta
Published: June 2004

Purified blood group A, B, and O substances from hog and human sources precipitate with Type XIV antipneumococcal horse serum and provide an explanation for the observation that Type XIV antibody agglutinates human erythrocytes of all four major blood groups.

Individual preparations of A substance or O substance from either species vary in their capacity to precipitate Type XIV antibody although the hog A substances did not differ in potency toward anti-A. Similarly, no correlation between A activity and reactivity with Type XIV antibody could be found among the human A substances.
THE NATURE OF THE VIRUS RECEPTORS OF RED CELLS
Authors: Hirst George K.
Published: June 2004

Evidence has been offered that influenza virus which has been heated at 56°C. for 30 or more minutes loses some of its capacity to agglutinate red cells and may completely lose its power to elute from cells on which it has been adsorbed. Such heat-inactivated virus does not possess the capacity to destroy the virus inhibitor in normal rabbit serum and this appears to be the explanation of the higher agglutinin inhibitory levels obtained with serum and heated virus as compared with serum and untreated virus.

The heat-inactivated virus can be used to measure the inhibitor substance in normal rabbit serum. By two different methods it has been demonstrated that the inhibitor is destroyed in the presence of unheated influenza virus, as measured by inhibition titrations with virus inactivated at 56°C. The destruction of inhibitor by virus of either type A or B can be measured by virus of either type with similar results.
THE EFFECT OF NITROGEN MUSTARDS ON ENZYMES AND TISSUE METABOLISM
Authors: Barron E. S. Guzman , Bartlett Grant R. , Miller Zelma Baker , Meyer Joe , Seegmiller J. E.
Published: June 2004

Nitrogen mustards at a concentration forty times the minimum lethal dose inhibited the respiration of all tissues studied but affected anaerobic glycolysis very little. The inhibiting effect increased with time. The respiration of lymphoid tissue was extremely sensitive to nitrogen mustard, as concentrations below the LD50 definitely inhibited the respiration of rabbit lymph nodes. In tissue slices nitrogen mustards inhibited the oxidation of pyruvate and of l-amino acids and the utilization of NH3. A number of synthesis reactions were also inhibited, such as the synthesis of carbohydrate, of creatine, and of urea. When added to growing seeds, nitrogen mustards inhibited their growth. In rats given lethal doses of nitrogen mustards there were found complete inhibition of choline oxidation and strong inhibition of pyruvate oxidation by the kidney and partial inhibition of urea synthesis by the liver. Inhibition of bone marrow respiration by nitrogen mustards was prevented by the addition of choline, and of dimethylaminoethanol plus methionine The possible mechanism of nitrogen mustard intoxication is discussed.
TUBERCULOSIS OF RABBITS INDUCED BY DROPLET NUCLEI INFECTION
Authors: Ratcliffe H. L. , Wells W. F.
Published: June 2004

Rabbits were caused to inhale known numbers of virulent bovine tubercle bacilli as separated cells in droplet nuclei.

For approximately 5 weeks after infection the growth of the bacilli and the response of rabbits to their growth was homogeneous; i.e., all reacted in the same way and to the same degree.

After 6 weeks individual differences in the rate of progress of the initial tubercles and of the infection as a whole became evident. These variations in the response seemed to be influenced by the number of initial tubercles and by the number of bacilli found in the lesions.

It is concluded that, as evidenced by the homogeneous phase of infection, rabbits do not differ in their resistance to initial growth of bovine tubercle bacilli. However, the later, heterogeneous pattern of response suggests that these animals vary widely in their capacity to acquire resistance.
TUBERCULOSIS OF RABBITS INDUCED BY DROPLET NUCLEI INFECTION
Authors: Ratcliffe H. L. , Wells W. F.
Published: June 2004

At intervals from 2 to 11 weeks after normal rabbits had inhaled small numbers of virulent bovine tubercle bacilli as separated cells in droplet nuclei, groups of these animals received a single exposure to reinfection during which each animal inhaled about 20,000 separated bacilli.

Normal control rabbits which inhaled this large number of bacilli died within 4 weeks thereafter. Their deaths were attributed to destruction of the lungs by developing initial tubercles.

Eleven of 12 rabbits which were reinfected within 4 weeks after initial infection seemed to respond as normal animals. Their lungs were largely replaced by developing reinfection tubercles when they died or were killed within 32 days after reinfection.

The inflammatory response of the reinfection tubercles was not consistently different from that of initial tubercles, although reinfection tubercles contained fewer bacilli than initial lesions of the same age.

Within 5 weeks after initial infection rabbits apparently had developed immunity to reinfection with virulent bovine tubercle bacilli inhaled as separated cells in droplet nuclei. In some of them, however, exposure to massive inhaled reinfection seemed to stimulate the progress of initial infection.

It is suggested that in rabbits the development of resistance to tubercle bacilli does not bear a linear relationship to time, but progresses in steps and within 5 weeks after small initial infection by inhalation is adequate to prevent the growth of separated bacilli when these are deposited upon alveolar walls.

It is suggested also that the basic effect of acquired resistance of rabbits to tubercle bacilli is inhibition of multiplication of the bacilli.
IMMUNOCHEMICAL STUDIES ON BLOOD GROUPS
Authors: Kabat Elvin A. , Baer Harold , Bezer Ada E. , Knaub Vesta
Published: June 2004

1. The effect of heating at varying pH on the cross-reactivity of hog blood group A and 0 substances with Type XIV antibody has been investigated. The hydrolysis of blood group A, B, and O substances from hog and human sources at pH 1.5–1.8 resulted in destruction of blood group activity and a marked increase in cross-reactivity with Type XIV antipneumococcus horse serum.

2. Analysis revealed the liberation of reducing sugar, most of which was dialyzable. It was further shown that the major part of the reducing sugar was fucose with small amounts of free and polymerized galactose and glucosamine. Non-glucosamine nitrogen, probably amino acids, also was found in the dialysate.

3. Paper chromatographic separation of the concentrated dialysate confirmed the presence of fucose and showed that the majority of the galactose and glucosamine occurred in polymeric form.

4. Quantitative analysis of the substances isolated from the paper showed good recovery of the various components, indicating that practically all of the material in the dialysate could be accounted for.

5. The methylpentose of human blood group A substance was identified as fucose.

6. The structure of the blood group substances is interpreted in terms of these results.
THE EFFECT OF WETTING AGENTS ON THE GROWTH OF TUBERCLE BACILLI
Authors: Dubos René J. , Middlebrook Gardner
Published: June 2004

Tween 80 and Triton A20 are two water-dispersible, non-ionic, surface-active agents which favor dispersed growth of tubercle bacilli in aqueous media probably by wetting the bacterial surface.

Tween 80 is a polyoxyethylene ester of sorbitan monooleate and is liable to enzymatic hydrolysis by lipases. Triton A20 in an arylalkyl polyether of phenol which appears resistant to the known enzymes of animal tissues.

Tween 80 loses its ability to disperse cultures of tubercle bacilli in media containing serum; Triton A20 does not.

Tween 80 increases the yield of growth, probably by supplying oleic acid to the bacilli; Triton A20 does not.

In concentrations sufficient to cause dispersed browth, Tween 80 (purified by removal of unesterified fatty acid) and Triton A20 are completely innocuous for virulent tubercle bacilli. However, Triton A20 exhibits a marked toxic effect on the avirulent variants of mammalian strains; Tween 80 does not.

The two wetting agents also differ in their effects on the morphological aspects of the bacterial cultures. Whereas Triton A20 prevents the formation of large amorphous bacillary clumps, it is less effective in preventing the orientation of the virulent bacilli resulting in the formation of long bacillary strands. Tween 80 on the contrary prevents also the formation of these cords of bacilli and exerts therefore a more effective dispersing effect on cultures of virulent tubercle bacilli.
THE EFFECT OF NUCLEIC ACIDS AND OF CARBOHYDRATES ON THE FORMATION OF STREPTOLYSIN
Authors: Bernheimer Alan W. , Rodbart Marcelle
Published: June 2004

1. Ribonucleic acid of yeast causes the formation of a potent hemolysin in broth cultures of Streptococcus pyogenes.

2. The hemolysin whose formation is induced by yeast ribonucleic acid appears to be identical with streptolysin S.

3. Desoxyribonucleic acid, products of acid or alkaline hydrolysis of ribonucleic acid, or many other substances tested, fail to produce a similar effect.

4. Digestion by ribonuclease increases markedly the streptolysin-inducing activity of certain preparations of ribonucleic acid.

5. A fraction (AF) of yeast nucleic acid has been isolated which possesses approximately 100 times the streptolysin-inducing capacity of the starting material. Some of the properties which distinguish AF, a polynucleotide, from ordinary yeast nucleic acid are described. AF is associated with the ribonuclease-resistant fraction of yeast nucleic acid.

6. Ribonucleic acid prepared from streptococci, wheat germ, and mammalian liver, and subsequently treated with ribonuclease, is about as active in causing streptolysin formation as ribonuclease-treated yeast nucleic acid.

7. Ribonucleic acid of tobacco mosaic virus, tested under comparable conditions, was found to be inactive.

8. Ribonucleic acid prepared from streptococci, wheat germ, and tobacco mosaic virus resembles yeast nucleic acid in possessing a ribonuclease-resistant fraction.

9. In addition to AF, a factor (or factors), present in meat infusion and in peptone, was found to be required for the formation of streptolysin.

10. The factor can be partially replaced by any one of several carbohydrates, the most active being maltose, glucosamine, and trehalose, in that order.

11. When appropriate concentrations of AF, maltose, and glucose are used, the nucleic acid-induced streptolysin can be produced in a medium whose chemical composition is essentially defined.
STUDIES ON NEWCASTLE DISEASE VIRUS
Authors: Bang F. B.
Published: June 2004

The application of the 50 per cent embryo mortality to a study of the virus of Newcastle is described. It has been evaluated by a series of duplicate titrations of the same sample of virus. In seven such titrations the largest difference between the two was 10–0.4. It is therefore believed that a difference of 0.6 log is probably significant and of 1.0 log almost certainly significant. This would mean that we can almost certainly detect a loss of 90 per cent of activity.

Neither temperature of incubation nor route of inoculation in the test embryos had consistent effect on the measurement of virus activity. The effect of increasing age of the incubated embryo, from 10 days up to 16 days, is slight and inconsistent. The addition of chicken red blood cells to a dilution of virus may lower the titer of the preparation, but the change is not sufficient to be of importance in the routine handling of the virus.
OBSERVATIONS ON THE FEVER CAUSED BY BACTERIAL PYROGENS
Authors: Bennett Ivan L.
Published: June 2004

The relationship between the fever of acute infection and that following injection of bacterial pyrogen was studied by administering pyrogens to animals convalescent from acute infections.

Rabbits surviving dermal pneumococcal infections or peritonitis due to Escherichia coli were given intravenous injections of typhoid or E. coli vaccine. They showed no evidence of tolerance to the fever-promoting effect of these pyrogenic materials.

Tolerance did develop in infected animals given daily pyrogen injections during the course of the infection.

Certain previous observations upon the ability of rabbits to develop tolerance to pyrogens, the broad nature of the tolerance, and its duration were confirmed.

It is concluded that the pyrogen produced by certain bacteria plays little or no rôle in the production of the fever of infection.

These findings are compatible with the hypothesis that there is a common factor, perhaps a product of cell injury, underlying the fever accompanying diseases of various types.
LEPTOSPIROSIS IN CATTLE
Authors: Baker James A. , Little Ralph B.
Published: June 2004

From abnormal milk of cows an agent has been transmitted to guinea pigs, rabbits, mice, and embryonated eggs. This agent caused a febrile reaction in guinea pigs and rabbits and an inapparent infection in mice. In early passages embryonated eggs were unaffected but later death of embryos occurred 7 days after inoculation. When blood from infected guinea pigs or chorioallantoic fluid from infected eggs was inoculated subcutaneously or intranasally into young calves, fever with albuminuria and more rarely hemoglobinuria was produced, in lactating cows the infection resembled that seen in animals with natural disease. Pen contact of normal cows and calves with infected calves resulted in inapparent infection. Autopsies showed that in addition to causing altered milk secretion, the agent damaged the kidneys and produced an interstitial nephritis. The agent was recovered from blood and milk during the febrile period and was demonstrated in the urine for periods long afterwards. Antibodies for the spirochete were found in the sera of experimental animals and of cows recovered from the natural disease.

The blood of infected guinea pigs, the chorioallantoic fluid from infected eggs, and the blood or urine from experimentally infected calves yielded a culture of a spirochete which appeared identical with the infective agent in comparative tests of physical, pathogenic, and immunological properties.
EPIDEMIC DIARRHEAL DISEASE OF SUCKLING MICE
Authors: Pappenheimer Alwin M. , Cheever F. Sargent
Published: June 2004

1. Cytoplasmic inclusions were found in the epithelial cells of the small intestine in a major proportion of suckling mice suffering from the spontaneous or experimentally produced diarrheal disease now prevalent in this laboratory.

2. They were not found in healthy stock mice of corresponding age.

3. Feeding of intestinal extract from healthy mice did not produce diarrhea or inclusions.

4. Feeding of boiled extract from diarrheal mice did not lead to the formation of cytoplasmic inclusions, when precautions were taken to prevent accidental infection.

5. The inclusions were regularly present only in the first few days of the disease. The inclusion-bearing cells desquamated. There was no inflammatory reaction.

6. Attention is called to the frequent presence of large numbers of Gram-positive coccoid bodies in the intestinal contents of suckling mice with diarrhea.
THE INFLUENCE OF RELATIVE HUMIDITY ON THE INFECTIVITY OF AIR-BORNE INFLUENZA A VIRUS (PR8 STRAIN)
Authors: Lester William
Published: June 2004

White mice were exposed to atmospheres containing known amounts of atomized influenza A virus (PR8 strain) of constant potency under conditions of varying humidity. It was found that an amount of atomized virus suspension which produced a 100 per cent mortality rate in animals exposed at 30 and 80 per cent relative humidity, respectively, resulted in the death of only 22.5 per cent of mice at a humidity of 50 per cent. The humidities between these values gave intermediate results.

The infectivity of the air-borne virus decreased so rapidly at a humidity of 50 per cent that it was impossible to secure a 100 per cent mortality rate in the exposed mice even by greatly increasing the dose of virus atomized.

The use of a dialyzed virus suspension at a humidity of 50 per cent resulted in the death of all exposed mice. This suggested that the deleterious influence of humidity was related to the presence of sodium chloride in the atomized suspension.

These findings with influenza virus closely resembled those obtained by Dunklin and Puck with pneumococci, streptococci, and staphylococci which would suggest that the factor responsible for the lethal effect of humidity is common to moist particles containing either the above-mentioned bacteria or influenza A virus.
THE HUMAN ANTIBODY RESPONSE TO SIMULTANEOUS INJECTION OF SIX SPECIFIC POLYSACCHARIDES OF PNEUMOCOCCUS
Authors: Heidelberger Michael , MacLeod Colin M. , Di Lapi Marie M.
Published: June 2004

A new experimental procedure for the production of arteriosclerosis in the bird is described. The subcutaneous implantation of diethylstilbestrol by means of which a sustained increase in the concentration of cholesterol, phospholipid, and neutral fat can be readily established, is shown to induce atherosclerosis of the aorta.

The atherosclerosis has been compared with that artificially induced in the bird by the prolonged feeding of cholesterol and also with that occurring spontaneously. The stilbestrol-induced lesion more closely resembled the spontaneously occurring one in the bird than did that produced by cholesterol feeding. But all 3 lesions were fundamentally similar, differing only in the amounts and proportions of the various lipid constituents present.

The concentrations of cholesterol in plasma of the stilbestrol-treated and cholesterol-fed birds were of the same order. Yet cholesterol constituted a greater proportion of the lipids deposited in the arterial wall of the cholesterol-fed than in that of the stilbestrol-treated birds. This finding suggests that the cholesterol content of the vascular lesion depends not only on the absolute concentration of cholesterol in plasma, but also on the proportion of cholesterol to other lipid constituents in plasma.
STUDIES ON A PROTEOLYTIC ENZYME IN HUMAN PLASMA
Authors: Ratnoff Oscar D.
Published: June 2004

Methods are described for the assay of chloroform-activated and fibrinolysin-activated plasma proteolytic enzyme, and for the determination of the inhibitory activity of plasma or other substances against chloroform-activated enzyme.

The inhibitory activities of plasma, serum, and crude plasma albumin against chloroform-activated plasma proteolytic enzyme were proportional to the logarithm of the concentration of the inhibitory substance tested. This suggests that enzyme and inhibitor react in accordance with the law of mass action.

The rate of fibrinolysis of recalcified plasma clots could not be related to the total proteolytic activity available in the plasma, nor to the inhibitory activity of fresh plasma or serum against plasma proteolytic enzyme.

During the incubation of a recalcified plasma clot at 37°C., the inhibitory activity of its serum against plasma proteolytic enzyme decreased until a minimal stationary level was reached. The clot lysis time could be correlated directly with the time which elapsed until this minimal level was reached.
REACTIONS BETWEEN INFLUENZA VIRUS AND A COMPONENT OF ALLANTOIC FLUID
Authors: Hardy Paul H. , Horsfall Frank L.
Published: June 2004

Evidence is presented which shows that there is a component present in normal allantoic fluid, probably mucoprotein in nature, capable of combining with influenza A virus (PR8), and that following combination between this component and the virus only partial dissociation of the complex occurs. Evidence is also presented which strongly suggests that the component is present in virus-infected allantoic fluid in which it is in part combined with the virus and in part free although altered by viral action. The probability that the component is present as well in highly purified preparations of influenza virus, and its effect upon various reactions obtained with this agent are discussed.
THE SUSCEPTIBILITY OF THE HAMSTER TO MOUSE ENCEPHALOMYELITIS VIRUS
Authors: Dean Donald J. , Dalldorf Gilbert
Published: June 2004

The OT strain of mouse encephalomyelitis virus induces an inapparent infection in suckling hamsters associated with lesions of the central nervous system and skeletal muscles. The virus increases in pathogenicity after alternating mouse-hamster transfers and then induces both paralysis and encephalitis. Pathogenicity is lost through serial hamster passages but is restored by a single mouse transfer.
CONCURRENT INFECTION WITH INFLUENZA VIRUS AND MUMPS VIRUS OR PNEUMONIA VIRUS OF MICE (PVM) AS BEARING ON THE INHIBITION OF VIRUS MULTIPLICATION BY BACTERIAL POLYSACCHARIDES
Authors: Ginsberg Harold S. , Horsfall Frank L.
Published: June 2004

Preexisting infection with PVM or mumps virus does not prevent multiplication of the virus of influenza A or B in the same tissue. Similarly, pre-existing infection with one or another of the influenza viruses does not prevent multiplication of either PVM or mumps virus in the same tissue. The failure of these two groups of viruses to interfere with the multiplication of each other is discussed in relation to the mechanism of inhibition of multiplication of mumps virus and PVM by the capsular polysaccharides of Friedländer bacilli, and the ability of influenza A and influenza B viruses to multiply in the presence of large quantities of these carbohydrates. It is suggested that differences in the requirements of the two groups of viruses for host cell metabolic systems may serve to explain both the lack of interference between them and the differing effect of polysaccharides upon their multiplication.
CELL BLOCKADE IN NEWCASTLE DISEASE OF CHICKENS AND CHICKEN EMBRYOS
Authors: Bang F. B.
Published: June 2004

The problem of cell blockade or interference has been studied using Newcastle disease of chickens as a model. Embryos may be protected against the uniformly lethal effect of the virus by previous inoculation with ultraviolet-irradiated virus. It was necessary to use 0.5 to 1 mg. of partially purified washed virus in order to demonstrate this effect. Blockade by inactive virus in the embryo was not complete, since it could be overcome by inoculating increasing amounts of active virus or by injecting the active virus into the allantoic sac instead of placing it on the membrane. The lethal effects of small doses of Newcastle virus could also be blocked by previous infection of the embryo with either swine influenza virus or human influenza A. Again this blockade may be overcome by using larger doses of active Newcastle virus.

Simultaneous injection of chickens with viruses of equine encephalomyelitis and a virulent strain of Newcastle disease virus merely delayed the incubation period of the Newcastle virus a day or so. Simultaneous inoculation of chickens with virulent and avirulent Newcastle strains caused complete blocking of the virulent strain. This blocking or interfering effect of the avirulent strain could be demonstrated 1 or 2 days after the inoculation of the virulent strain but was not effective after symptoms of the virulent disease had set in.
THE EFFECT OF DIET ON THE SUSCEPTIBILITY OF THE MOUSE TO PNEUMONIA VIRUS OF MICE (PVM)
Authors: Leftwich William B. , Mirick George S. ,   With the Technical Assistance of Miss Elizabeth I. Corddry
Published: June 2004

Young mice fed diets deficient in pyridoxine or fed desoxypyridoxine after the inoculation of the pneumonia virus of mice were more resistant to infection than well nourished controls.

The susceptibility of young mice to PVM increased with the duration of pyridoxine administration after inoculation.

Dietary protein restriction when pyridoxine was provided did not affect the susceptibility of mice to PVM.

The PVM-combining capacity of mouse lung and the titer of humoral antibody against PVM were the same in mice fed a complete or pyridoxine-deficient diet for 6 days.

The amount of PVM in mouse lungs 6 days after inoculation was greater by both infectivity and hemagglutination titrations in mice fed pyridoxine than in pyridoxine-deficient controls. This suggests that pyridoxine was essential during the postinoculation period for optimal virus multiplication.
THE MOVEMENT OF WATER IN TUMOR TISSUE REMOVED FROM THE BODY
Authors: Opie Eugene L.
Published: June 2004

When immersed in water cells of hepatomas produced by p-dimethyl-aminoazobenzene (butter yellow) take in less water than liver cells from which they are derived and more rapidly undergo disintegration; cholangiomas produced by butter yellow undergo similar changes.

As a result of the injury of the tumor cells by water the osmotic exchange, characteristic of the normal liver cells under the same conditions, is impaired within the initial half hour of immersion.

Solutions of sodium chloride isotonic for hepatoma tissue have a concentration approximating 0.16 molar and for cholangioma, 0.2 molar, whereas solutions isotonic for normal liver tissue approximate 0.34 molar.

Water exchange of hepatoma and of cholangioma tissue in solutions of sodium chloride of various concentrations deviates from a proportional relation to the concentration more than does normal liver tissue under the same conditions.

Water exchange of sarcoma of the subcutaneous tissue produced by benzpyrene when immersed in water resembles that of interstitial fibrous tissue of normal animals, but by the procedures that have been used water exchange of the tumor cells alone has not been measurable. Microscopic examination indicates that the sarcoma cells are as susceptible to injury as those of the other tumors that have been examined.

Intake of water by adenofibromas of the subcutaneous tissue is apparently dominated by changes in the dense stroma of the tumor and has the anomalous character of intake bycompact fibrous tissue of the corium of the skin and of the wall of the aorta.
THE NATURE OF THE VIRUS RECEPTORS OF RED CELLS
Authors: Hirst George K.
Published: June 2004

Influenza virus, treated with sodium periodate, was adsorbed well on red cells but lacked the capacity for spontaneous elution. Heated virus was eluted from red cells by the action of cholera vibrio filtrate, unheated influenza virus, and to a small extent by heating at 56°C. Periodate-treated virus was not elutable by these methods but was liberated by exposure of the adsorbing cells to concentrations of sodium chloride of 5 to 10 per cent. This treatment had no effect on elution of heated virus.
FURTHER OBSERVATIONS ON THE PRODUCTION AND PREVENTION OF DIETARY HEPATIC INJURY IN RATS
Authors: György Paul , Goldblatt Harry
Published: June 2004

The present report on experimental hepatic injury is based on observations amassed during the last 9 years, comprising 1922 rats.

It has been shown that there are several dietary factors which may intervene, singly or in combination, in the development of massive or zonal hepatic necrosis. Deficiency of sulfur-containing amino acids is only one of them. From the present studies, tocopherol emerges as an additional protective dietary factor. With regard to the development of massive hepatic necrosis tocopherol may compensate for the absence of sulfur-containing amino acids (cystine, methionine) and vice versa. As a further factor, the quality of dietary fat should be taken into consideration. Fats, like lard and cod liver oil, with a high content of unsaturated fatty acids enhance, whereas fats low in unsaturated fatty acids, such as crisco and butter, retard or prevent the development of massive hepatic necrosis.

It is questionable whether with all these dietary factors the etiology of massive hepatic necrosis is completely defined.

The interchangeability of sulfur-containing amino acids (cystine, methionine) and vitamin E as leading etiologic factors makes it difficult to accept pure deficiency as the basis of massive hepatic necrosis. The rôle of possible endogenous hepatotoxic substances and their neutralization by cystine (methionine) or tocopherol are discussed.

Diffuse hepatic fibrosis is a regular occurrence in rats kept for 100 to 150 days on a diet low in lipotropic factors. Cystine, and, among the fats, lard and especially cod liver oil, have an enhancing effect on the production of hepatic cirrhosis. In rats fed rations free from cod liver oil, and with vegetable shortening such as crisco as source of fat, the incidence and severity of cirrhosis are reduced.

Ceroid deposit accompanies cirrhosis only in rats which have been kept on a cirrhosis-producing diet containing fats with a high content of unsaturated fatty acids (cod liver oil, lard). Tocopherol, even when given in excessively large doses (30 mg. daily) will not prevent the formation of ceroid, and will reduce only slightly its total quantity. Under the same treatment the incidence and intensity of cirrhosis remain uninfluenced.

Cellular injury in the form of degenerated or necrotic hepatic parenchymal cells, found singly or in small groups in and around the fibrous bands in the cirrhotic liver of rats, is a common occurrence. The fibrotic changes seem to begin, not in the portal spaces, but close to the central vein, although they are not as distinctly and exclusively pericentral as, for instance, in cardiac cirrhosis. Thus, experimental dietary cirrhosis is non-portal.

The role of fat infiltration is discussed with special reference to the other microscopic changes found in hepatic cirrhosis.

Acute necrotizing nephrosis or various stages of healing of this process are often found with great frequency in rats kept on a cirrhosis-producing diet.
INDUCTION OF METASTASIS OF FROG CARCINOMA BY INCREASE OF ENVIRONMENTAL TEMPERATURE
Authors: Lucké Balduin , Schlumberger Hans
Published: June 2004

Metastasis of the kidney carcinoma of leopard frogs (Rana pipiens) has been induced by exposing tumor-bearing animals for approximately 50 days to a constant temperature of 28°C. Under these conditions 54 per cent of the frogs developed secondary growths, whereas in groups kept at 18° or at 7° metastatic dissemination was found in only 6 per cent. Moreover, at the elevated temperature the metastases were usually more numerous and more widely disseminated; they were also fairly uniform in size, suggesting that they had developed at nearly the same time.

Dissemination of the kidney tumors was influenced by the nutritional state of the frogs, occurring more readily in well nourished than in poorly nourished animals.

Periodic Roentgen ray examinations showed that the size of the primary tumors was not significantly or uniformly affected during the course of the experiments. No correlation was found between change in size of the kidney tumors and the incidence of their metastasis.

Although the mechanism by which temperature induces metastasis of frog carcinoma cannot as yet be elucidated, previous experiments with this tumor indicate that certain factors at least may be involved: Elevation of temperature has been found to cause more ready detachment of cells of frog carcinoma in tissue culture; to bring about increased velocity of locomotion of the detached cells; to lead more promptly and efficiently to vascularization of transplants; and to effect their greater invasiveness.
OBSERVATIONS ON THE PREGNANT RAT INJECTED WITH NEPHROTOXIC RABBIT ANTI-RAT PLACENTA SERUM AND DESOXYCORTICOSTERONE ACETATE
Authors: Loeb Emily N. , Knowlton Abbie I. , Stoerk Herbert C. , Seegal Beatrice C.
Published: June 2004

1. Pregnancy enhances the susceptibility of the rat to intercurrent renal damage produced by anti-placenta serum. This is manifested by the development of renal hypertrophy and nephritis in a number of these animals. Both renal hypertrophy and nephritis are consistently intensified by the concomitant administration of DCA.

2. Hypertension develops in both pregnant and non-pregnant rats treated with the anti-placenta serum employed together with the daily administration of DCA.

3. Termination of pregnancy, in the face of continued DCA administration, fails to lower the blood pressure or to arrest the nephritic process.
QUANTITATIVE STUDIES ON THE TOTAL PLASMIN AND THE TRYPSIN INHIBITOR OF HUMAN BLOOD SERUM
Authors: Todd Edgar W.
Published: June 2004

The total plasmin and the trypsin inhibitor were titrated separately in samples of serum taken at weekly intervals from three different groups of scarlet fever patients: (a) those who did not develop any complications, (b) those who developed purulent complications, and (c) those who developed rheumatic fever.

When these determinations were plotted, it was found that the resulting curves showed characteristic patterns for each of the diseases investigated.

The uncomplicated cases had plasmin curves which were considerably higher on the charts than the inhibitor curves.

The septic cases had plasmin and inhibitor curves which were closer together on the charts.

The rheumatic cases had plasmin and inhibitor curves which were close together and which crossed at the time of rheumatic activity so that the inhibitor curve reached a higher level than the plasmin curve.
DIETARY EFFECTS ON ANEMIA PLUS HYPOPROTEINEMIA IN DOGS
Authors: Robscheit-Robbins F. S. , Whipple G. H.
Published: June 2004

Casein (purified or commercial) in this type of experiment falls in the top bracket as a protein consistently favorable for maximal new hemoglobin and plasma protein production in doubly depleted dogs (anemic and hypo-proteinemic).

Lactalbumin is less favorable for total blood protein production and the ratio of plasma protein to hemoglobin is high—that is lactalbumin favors plasma protein production as compared with casein, or is less favorable for hemoglobin production.

Peanut flour (purified or commercial) is less than half as effective as casein in promoting new blood protein production. The ratio of plasma protein to hemoglobin is about the same as casein.

Wheat gluten as tested is distasteful to dogs. It is neither very good nor very poor for blood protein production when it is eaten. There is nothing unusual about the response. Weight loss usually confuses the picture.

Liver stands as a control base line for the above experiments. Its capacity to further hemoglobin and plasma protein production is well established. The production of hemoglobin was about 3 times that of plasma protein in the experiments.
IMMOBILIZATION OF TREPONEMA PALLIDUM IN VITRO BY ANTIBODY PRODUCED IN SYPHILITIC INFECTION
Authors: Nelson Robert A. , Mayer Manfred M. ,   With the Assistance of Judith A. Diesendruck, Sc.D., and John T. Eagan
Published: June 2004

Treponema pallida were extracted from rabbit testicular syphilomas and suspended in a special medium in which the organisms remain motile and infectious for several days. On incubation of such suspensions with syphilitic rabbit or human sera and guinea pig complement, the treponemes became non-motile and lost their capacity to infect rabbits. Various factors affecting this immobilization have been investigated.

In a preliminary survey of individual sera, immobilizing antibody could be detected in the majority of sera from syphilitic animals and human beings, but was absent in almost all the normal sera examined.

It could be demonstrated that the immobilizing and reagin activities of syphilis sera are due to separate antibodies.
ADDITIVE EFFECTS OF CERTAIN TRANSFORMING AGENTS FROM SOME VARIANTS OF PNEUMOCOCCUS
Authors: Taylor Harriett E.
Published: June 2004

It has proved possible to transform an extreme rough variant of pneumococcus back to the rough state by the action of the desoxyribonucleate fractions of either rough or Type III smooth pneumococci. In a second step, the rough pneumococci produced by this transformation were further changed to the Type III smooth state by means of the desoxyribonucleate fraction of Type III smooth organisms. With use of the Type III desoxyribonucleate, the two steps could be accomplished successively, but not simultaneously, during the growth of a single inoculum of the extreme rough form.

These findings have been interpreted as indicating that the desoxyribonucleic acid fraction of Type III smooth pneumococci contains two transforming principles of differing specificity, while the same fraction of rough pneumococci contains but one of these principles.

Two distinct spontaneous variants of Type III smooth pneumococci have been isolated which seem to differ from normal Type III smooth pneumococci in synthesizing smaller amounts of the specific polysaccharide. Tests have indicated that these variant Type III races differ from the normal in possessing altered Type III transforming principles. Each of the new transforming agents when influencing rough bacteria, is strictly specific in its action, inducing as it does the formation of the corresponding variant Type III pneumococci.

Interaction between the two new transforming principles and rough pneumococci can lead to the production of normal Type III organisms, although neither principle alone can do it. This is interpreted as indicating that the two mutated Type III transforming principles are qualitatively different from each other.

Another kind of two-step transformation was accomplished by converting rough pneumococci first into the variant Type III pneumococci which produced very little specific polysaccharide, and then by transforming these latter into normal Type III organisms.

After the two-step transformation of the extreme rough pneumococcus, both transforming principles used to effect this can be recognized in the Type III smooth pneumococci finally recovered. By contrast, in the two-step transformation of the rough pneumococcus by way of an intermediate smooth form, only the second transforming principle can be obtained from the resulting fully smooth organisms.

The meaning of these facts is discussed.
ELECTRON MICROSCOPE STUDIES OF CELLS BY THE METHOD OF REPLICAS
Authors: Claude Albert
Published: June 2004

The method of replicas has been applied to the study with the electron microscope of blood cells and bacteria.

The results indicate that the method can reveal details of intracellular structures. Nuclei can be perceived, and also cytoplasmic bodies such as mitochondria and vacuoles.
ACQUISITION OF M PROTEIN BY PNEUMOCOCCI THROUGH TRANSFORMATION REACTIONS
Authors: Austrian Robert , MacLeod Colin M.
Published: June 2004

Acquisition by pneumococcal variants of M protein and of capsular polysaccharide different from those present in the parent strain has been effected in vitro by means of transforming reactions with extracts of heterologous encapsulated pneumococci. Similar transformations have been accomplished in vivo with heat-killed vaccines as the transforming agents.

Independent variation of pneumococcal capsular polysaccharide and M protein observed in nature can be brought about also in the laboratory. By means of transforming reactions, it has been demonstrated that inheritable characters of three distinct pneumococcal strains can be combined within a single strain.

It is suggested that acquisition of M protein through transformation reactions occurs in cells deficient in that character.
THE CYTOLOGY OF RICKETTSIAE
Authors: Ris Hans , Fox John P.
Published: June 2004

Internal structures of rickettsiae seen with phase contrast microscopy and in the electron microscope contain desoxyribonucleic acid and are therefore nuclear structures similar to those found in bacteria. They are minute spherical bodies, either single as in spherical rickettsiae or varying in number from 2 to 4 in rod-shaped forms. Occasional dumbbell-shaped chromatinic bodies are thought to represent these structures in the process of division. The presence of ribonucleic acid in the cytoplasm of rickettsiae was demonstrated with the use of ribonuclease and basic dyes. Rickettsiae therefore have a cellular organization similar to that of certain bacteria, with a clear differentiation into nuclear structure and cytoplasm.
THE RÔLE OF THE "WAX" OF THE TUBERCLE BACILLUS IN ESTABLISHING DELAYED HYPERSENSITIVITY
Authors: Raffel Sidney , Arnaud Louis E. , Dukes C. Dean , Huang Jwo S.
Published: June 2004

Guinea pigs sensitized with egg albumin along with the purified wax fraction of the human tubercle bacillus respond with delayed hypersensitive reactivity to the protein antigen. Previous publications have reported a similar activity of the wax with respect to tuberculoprotein and picryl chloride. The effect is not referable to an ordinary adjuvant activity of the bacillary wax, since antibody titers are not increased in animals which receive it, and since a known adjuvant, water-in-oil emulsion, has no effect with respect to the induction of delayed hypersensitivity.

This report further extends the rôle of the tubercle bacillary wax in the induction of delayed hypersensitive states.
ISOLATION FROM CASES OF INFANTILE DIARRHEA OF A FILTRABLE AGENT CAUSING DIARRHEA IN CALVES
Authors: Light Jacob S. , Hodes Horace L.
Published: June 2004

From instances of diarrhea of the newborn in four separate hospital outbreaks a filtrable agent was isolated which regularly produced diarrhea in calves. This agent appeared to have the characteristics of a filtrable virus.

The four strains of virus isolated in the outbreaks studied appeared to be identical or very closely related.

The virus was not found present in the stools of any of eight normal newborn infants or five normal calves.

Evidence is presented that the virus may be one of the causes of epidemic diarrhea of the newborn.