TYPHUS FEVER : IV. FURTHER OBSERVATIONS ON THE BEHAVIOR OF RICKETTSIA PROWAZEKI IN TISSUE CULTURES

In tissue cultures grown at 32°C., typhus Rickettsiae increase rapidly within the cytoplasm of infected cells up to about the 14th day. At this time practically every cell is infected and the majority of cells are distended with organisms. This condition remains constant as long as successful cultures of the cells can be maintained (up to 52 days). Loss in virulence does not take place during this period in vitro. The number of Rickettsia-filled cells found in sections and the incubation period of the infection resulting from inoculation of cultures from each age group are definitely correlated. The behavior of typhus Rickettsiae in dividing cells is described and methods of spread of the infection other than by mitosis of cells are discussed. Normal tissues do not become infected in vitroto any considerable extent in spite of prolonged proximity to heavily infected cultures of scrotal sac exudate. Complete anaerobiosis and alterations in pH do not alter the intracellular location of the organism in tissue cultures. The organisms are not seen within nuclei of infected cells. They remain intact and infective for several weeks in cells which are kept alive but not multiplying. They disappear in less than 1 week, however, when the cells undergo degeneration.     

SPOTTED FEVER : I. INTRANUCLEAR RICKETTSIAE IN SPOTTED FEVER STUDIED IN TISSUE CULTURE

Spotted fever infection has been studied in tissue cultures grown at 32°C. The behavior of spotted fever Rickettsiaeis compared and contrasted with that of typhus Rickettsiae under similar conditions. The spotted fever organisms multiply extensively in the nuclei of cells where they form spherical clusters of various sizes. These structures are compared and contrasted with intranuclear inclusion bodies.     

Gonococcus endocarditis: Report of a case

A fatal case of gonococcus endocarditis with detailed autopsy findings is reported. Acute endocarditis followed a urethritis and affected an aortic valve which was already damaged by rheumatism.In addition to acute vegetative endocarditis of the aortic valve, autopsy revealed chronic productive changes in both mitral and aortic valves, subendocardial abscess with extension to the pericardium, diffuse suppurative and hemorrhagic pericarditis, acute intracapillary glomerular nephritis, acute focal interstitial nephritis, parenchymatous degeneration of the kidneys, infarction and suppuration of the spleen, degeneration and congestion of the liver, suppurative gastritis, pulmonary congestion, bilateral hydrothorax, ascites, conjunctival petechiae, suppurative leptomeningitis, gangrene of the legs, and a decubitus ulcer.     

ETIOLOGY OF OROYA FEVER : XVI. VERRUGA IN THE DOG AND THE DONKEY

In the experiments here reported, definite verruga lesions, in which the presence of Bartonella bacilliformis was established by culture or by passage to rhesus monkeys, were produced in a dog and in a donkey by inoculation of cultures or monkey passage strains. The reaction induced in these animals was entirely local, however; blood cultures were sterile. Histologically, the lesions produced were similar to those obtained in monkeys by inoculation of Bartonella bacilliformis, except for the presence of a marked polynuclear leucocytic exudate. In another donkey a lesion histologically suggestive of verruga was produced, while in one donkey and a horse the results of inoculation were negative or indefinite. The intravenous injection of a filtrate or of heat-killed cultures of Bartonella bacilliformis into two donkeys was followed by the appearance of large, soft, subcutaneous swellings, on various parts of the body, not resembling in any way verruga lesions.     

THE CONCENTRATION OF THE PROTECTIVE BODIES IN ANTIPNEUMOCOCCUS SERUM. SPECIFIC PRECIPITATE EXTRACTS

1. The protective substances contained in specific precipitates from antipneumococcus serum can be extracted by suitable chemical and physical agents, dilute sodium carbonate at 42°C. being especially advantageous as an extractive agent. 2. The resulting water-clear extracts, when made up to the original volume of the serum used for precipitation, protect animals almost as well as does the whole serum. 3. The bacterial extracts used in precipitating the protective substances from the serum act specifically; that is, a bacterial extract of pneumococcus of Type I removes the protective substances from a Type I immune serum only. 4. In a polyvalent serum of Type I and Type II, the protective substances of each type may be removed independently of each other by the successive addition of the homologous antigens. 5. Extracts of specific serum precipitates contain only one-fiftieth to one-sixtieth of the protein in the original serum, and about one-half the protein of the whole precipitate. 6. Extracts contain not only protective substances but agglutinins and precipitins. 7. Extracts and whole precipitates not only confer passive immunity but stimulate the production of active immunity to pneumococcus infection in rabbits and mice.     

INFLUENZA : II. EFFECT OF INFLUENZA VIRUS MULTIPLICATION ON THE OXYGEN CONSUMPTION CURVES OF EMBRYONATED EGGS INCUBATED AT DIFFERENT TEMPERATURES

In addition to the cycles of growth shown by the influenza A virus during the first 24 hours of its residence in the fertile egg, cycles separated by longer time intervals have been noted between the 24th and 96th hours. These longer cycles are best seen when the eggs are incubated at 40°C. Corresponding fairly accurately with these cycles of growth of the virus, wide cyclic variations in the rates of increase in oxygen consumption of the infected eggs have been found to occur. These variations are in striking contrast to the uniformity of increase noted in uninfected eggs. The variations in infectivity may be caused by periodic interference with virus multiplication by accumulated inactive virus particles. The variations in oxygen consumption probably are correlated with variations in the concentration of virus toxins.     

Histochemical studies on the dentin of magnesium-deficient rats

Characteristic striations form in the dentin of rats maintained on a diet deficient in magnesium. These striations were studied histochemically in both intact and parathyroidectomized rats. In the lower incisor teeth the striations occurred at intervals varying between 20 and 27μ. Each dentinal striation contained distinct zones of sudanophilic material, acid mucopolysaccharides, and PASpositive proteinpolysaccharides. Dentinal tubules appeared to be enlarged in the zone of sudanophilia. Striations in the dentin of parathyroidectomized rats were very similar to those in intact animals. Formation of dentinal striations ceased within 4 days when deficient animals were placed on a magnesium-supplemented diet.     

FATAL MURINE TYPHUS INFECTION IN THE dba STRAIN OF MICE,WITH OBSERVATIONS ON STRAIN VARIATION IN SUSCEPTIBILITY

Injected intracranially in the dba strain of mice, murine typhus rickettsiae caused a serially transmissible meningoencephalitis similar to that produced by psittacosis and certain other viruses. All injected mice of this strain suddenly became ill and approximately half of these animals died on the 5th and 6th days after injection. Swiss mice injected in parallel series showed illness in only a few animals, and no deaths occurred. These experiments were carried out at room temperatures ranging from 60–80°F. After intraperitoneal injection, a uniformly fatal rickettsial peritonitis developed in all dba mice kept at environmental temperatures of 65–73°F. or 70–80°F. Death occurred between the 3rd and 7th days after injection, depending somewhat on the dosage used. Among Swiss, brown agouti, and A albino mice injected in parallel series, the mortality was less than 60 per cent. These experiments indicate that mice of the dba strain are much more susceptible to murine typhus than are mice of the other three strains studied.