Morton C. Kahn

Bacteriostatic Properties of Histiocytes Toward Mycobacterium tuberculosis as Determined by the Single Cell Method.

Summary Under the experimental conditions described, it would seem that the histiocytes of normal guinea pigs are in many instances capable of exerting at least bacteriostatic properties toward engulfed Mycobacterium tuberculosis of the human variety when phagocytosis occurs in vivo. Of 101 tubes of Corpers egg medium seeded with a total of 4190 histiocytes, 1513 or 34.8% which had engulfed the mycobacteria, growth was obtained in only 2 instances, or 2%. When comparably small numbers of free Mycobacterium tuberculosis were inoculated upon the same medium, growth was obtained in 28.8% of the tubes employed. As no fragmentation of the bacteria within the histiocytes was observed, the bacteriostatic action exerted may be possibly explained as due to a disturbance in the metabolism of the engulfed Mycobacterium tuberculosis.

Aerobic bacteria in house dust

Abstract Bacteriologic study of thirty-eight samples of house dust collected in the New York area have revealed a flora which varies widely, qualitatively and quantitatively. Representatives of seven aerobic bacterial families were observed, only one of which, Bacillaceae, was consistently present. As determined by accepted biochemical tests, the bacteria appeared to be chiefly nonpathogenic forms.

A pernicious anaemia-like blood condition produced in monkeys with B. welchii toxin

In a recent article by Moench, Kahn and Torrey 1 a report was given of an analysis of the fecal flora in 33 cases of pernicious anæmia. The most striking feature revealed by these examinations was the constant presence of unusually large numbers of B. welchii in the stool specimens and presumably throughout the large intestine. These findings were a confirmation and extension of the earlier observations of Herter 2 and also of Simond. 3 It was suggested that the absorption of B. welchii toxin from the intestinal tract might conceivably be the essential etiological factor in the production of the clinical syndrome which characterizes pernicious anæmia, and that our findings justified further inquiry by experimental methods. In the present communication we wish to report in a preliminary way our observations on the effect of a potent B. welchii toxin on the blood of monkeys when injected intravenously. Several strains of B. welchii, isolated from different cases of pernicious anæmia, were compared as regards toxin production, employing the Bull and Pritchett 4 method of production, and injecting graded amounts of the filtered toxin into the wing vein of pigeons. Our strain “Navital” proved the best suited for our purposes but it was deemed advisable to enhance its virulence by animal passages. Accordingly it was passed through six successive rabbits by intravenous inoculation, and then through four pigeons by injections into the breast muscles and recovery from the lesions on the death of the bird. The virulence of the whole culture was finally such that 0.02 cc. caused death within 18 hours. Sterile filtrates of the culture were found to be, however, only slightly more toxic than the unpassed strain.

Transmission of Mouse Sarcoma with Small Numbers of Counted Gells.

Summary Sarcoma of mice can be transmitted with approximately 50 cells.

Tuberculosis Induced in the Tadpole by Feeding.

Aronson 1 isolated a strain of tubercle bacillus from an iguana which was found dead in the Philadelphia Zoo. A number of tubercles were seen in the lung of this animal and also in the liver. The spleen contained no gross tubercles. A single tubercle was found in the upper pole of the left kidney. In guinea pigs injected intracutaneously with this culture Aronson found that a small ulcer occurred at the site of inoculation. The glands became enlarged and succulent but went on to healing. The organism was found to be pathogenic for the chameleon and salamander and also for the frog. It was not pathogenic for the snake. As regards the frog Aronsons findings have been confirmed by Holly 2 and by the writers with a transfer of this organism which Aronson sent to us sometime ago for further study. Examination of stained slide preparations reveals the organism to be acid- and alcohol-fast. Ziehl-Neelsen stained vertical sections from growing colonies made with a technique reported by us 3 show some non-acid-fast rods in addition, but the tiny non-acid-fast rods and granules so conspicuous in vertical sections of human and bovine tubercle bacillus colonies are entirely lacking. It would seem then that this organism multiplies principally by simple fission. According to Henderson and Aronson 4 the organism is culturally and serologically identical with Mycobacterium marinum which was isolated from salt water fish. In view of the pathogenicity of this organism for frogs it occurred to the writers to determine whether a similar situation existed for tadpoles. If this proved to be the case the tadpole would make a valuable experimental animal for certain problems as the entire animal may be sectioned and all of the organs examined in the same creature at the same time. It would also permit investigations concerning the reaction of embryonic tissue toward infection by a member of the Mycobacterium group.

Electrophoretic Mobility Velocities of Rough and Smooth Avian and Bovine Tubercle Bacilli.

Falk 1 showed that the electrophoretic mobility velocity (potential difference) of diphtheria bacilli varied according to their virulence, the more virulent organisms showing low mobility rate, while those of a less virulent nature gave a higher reading. For pneumococcus, 2 on the contrary, he found that the potential difference is higher the greater the virulence for white mice and vice versa. The sequence of decreasing potentials was shown to be Types III, I, II, IV, which follows the decreasing virulence for white mice. This work on the pneumococcus was carried out prior to the isolation of several new types from the erstwhile group IV. Following the technique of Petroff 3 the writers undertook the dissociation of a stock strain of avian tubercle bacillus procured originally from Dr. Krumwiede of the Research Laboratories, New York City Department of Health. When the culture was planted on Proskauer and Beck medium after a suitable period of incubation at 37° C. the organism had dissociated into rough and smooth types of colonies. Representatives of each were selected and planted on glycerine agar and on Petroffs egg medium slants. After 5 generations the organisms are still truly representative of the original parent colonies from which they were taken. Other tests were performed on rough and smooth avian and bovine colonies dissociated by Dr. Petroff. In view of the hypothesis that smoothness of colony may be an indication of virulence, while roughness may be taken as an indication of the reverse, the writers determined the mobility velocities for the two types of colonies, using the Falk slide cell technique. The growths were washed once in distilled water just prior to the experiment and the procedure was adhered to as outlined originally by Falk.

The Possible Relationship Between Absorption of B. Welchii Toxin and Pernicious Anemia.

The experiments reported here are in continuation of our investigation of the possible relationship between the absorption of B. welchii toxin from the intestine, and the condition of pernicious anemia. In a previous communication 1 there was described a severe type of anemia produced in monkeys by the intravenous inoculation of small doses of potent B. welchii toxin. In all the animals, however, after 3 weeks treatment, an immunity became apparent which was not broken down even by a greatly increased dosage, although abnormalities of erythrocytes and a leucopenia persisted for some time. It was next attempted by the continued inoculation of dosages of B. welchii toxin just below the limit of toleration, to cause such serious injury to the hematopoietic system as might prove irreparable, and to induce a progressive degenerative condition resembling that of pernicious anemia. The method of toxin preparation was essentially as described heretofore, except that somewhat larger pieces of fresh sterile pigeon muscle were added to the casein digest broth. Employing our pernicious anemia B. welchii strain, “Navitol”, sterile toxins were obtained which were lethal for pigeons within 24 hours after intramuscular inoculation of 0.5 cc. Two young ring-tail monkeys (Cebus capucinus) were given a long series of intravenous toxin inoculations in dosage sufficient to keep the animals in a condition of more or less severe anemia for 9 to 10 weeks, in contrast with the 3 or 4 weeks period of the previous experiment. After about 10 weeks, however, in spite of greatly increased dosage, it was not possible to check the tendency of reversion toward normal, and we became convinced that intravenous inoculations of B. zerelchii toxin would not damage the hematopoietic tissues to such a degree that the condition was irreversible.

Mobility Velocities of Histiocytes from Normal and from Sensitized Guinea Pigs.

Summary With the technic described the mobility velocities of histiocytes obtained from normal guinea pigs were compared with those obtained from guinea pigs sensitized with the H37 strain of living Mycobacterium tuberculosis. The cells of the infected animals revealed a trend toward a slower rate. Statistically the difference obtained is significant as the range of the mean of the two in no point coincides. These findings may indicate a difference in surface charge.