No abstract

the percentage retention of Ca45 about twofold, while having no significant effect on Sr90 retention.The last column of Table 1 shows the total calcium derived from the diet, which is deposited and retained during the course of the experiment. These figures are calculated from the measured Ca45 concentration in the bone and the known ratio of Ca45 to stable calcium in the diet. While rather close physiological control of dietary calcium utilization is evidenced at the two lower dietary levels, this control is no longer very effective at the 2-percent calcium level.Blood levels of Sr90 and Ca45 at different times of sacrifice were reasonably constant within a given dietary group. Between dietary groups, the blood levels of Sr90 and Ca45 varied in essentially the same manner as their concentrations in the femur. In general, for a given group of animals, the ratio of Sr90/Ca45 in the blood was not significantly different from the ratio of Sr90/Ca45 in the bone; this suggests, as others have pointed out (2), that the major discrimination between dietary calcium and strontium does not occur in the specific processes of deposition on the bone. Because total calcium analyses on blood were not obtained, and in view of the limited time period studied, closer intercomparison of the blood and bone data with a view toward elucidating discrimination mechanisms would not seem to be justified.Wasserman et al. have recently described an experiment in which Sr90 and Ca45 were chronically administered with diets varying in total calcium content from 0.5 to 2.0 percent (4). The skeletal deposition of both Sr90 and Ca45 in their experiment was inversely proportional to

Five of 17 adenoviruses of rhesus or cynomolgus monkey origin induced tumors in newborn hamsters. The tumors appeared between 42 and 280 days after subcutaneous inoculation and had the general characteristics of lymphomas. The tumors were specific by cross-complement fixation tests. An adenovirus recovered from Cercopithecus monkeys appeared to be highly oncogenic; all 23 inoculated hamsters developed tumors within 30 to 40 days.

No abstract

No abstract

53SYNOPSIS. Experimental observation of the pathogenicity of some strains of Hartmannelkz plus the observation of human meningoencephalitis due to small amebas which had a structure compatible with that of Hartmannella in the tissues has suggested the concept af respiratory amebiasis followed by cerebral and other complica- tions.Until recently no cultural evidence was available to identify positively the amebas in the human cases. This report summarizes the isolation of Naegleria sp. (HB-I) from human spinal fluid by mouse inoculation followed by tissue culture of the infected mouse brain. C. Butt and his associates, who submitted this material to us, iso-OME stirains of free-living amebas of the family Hart-s mannellidae can grow in and destroy many different types of tissue culture; many of these isolates are pathogenic for animals. This report presents strong evidence (that another common free-living ameba of the family Schizopyrenidue, genus Naegleria, is similarly endowed with pathogenic capabilities.The spinal fluid from which the isolate was recovered was made available to us by Dr. Cecil Butt and his colleagues(1) who performed the autopsy and who also recovered the ameba in culture. Their findings are reported elsewhere. MATERIALS 1. Escherichia coli. This culture, used by Dr. B. N. Singh as nutrient for soil amebas, was obtained from him in 195T and maintained on Trypticase soy agar slants (transfer several times each week). This organism was originally referred to by Dr Singh and by us as Aerohacter yp. 2 . Naegleria gruheri. Known strains of this ameba growing with associated Gram-negative bacteria were obtained thru the courtesy of Dr. S. L. C h a w of Cincinnati, Ohio, and Prof William Balamuth of Berkeley, California. 3 . Tetramitw rostratus. Cysts of culture No. B 15811'1 were kindly supplied to us by Dr. J. L. Griffin of the Armed Forces Institute of Pathology. 4. Mice. SPF (Lilly) mice of the ND-4 line, caesarian-derived from germ-free animals, were used thruout these tests. 5. Tissue Culture. MK, (Lilly) continuous cell line of monkey kidney cells was utilized in roller tubes, Leighton tubes, or tissue culture bottles with Medium 199 containing 100 unilts of penicillin G and 100 Ng of streptomycin per ml. METHODS Direct microscopic examination.Both phase and ordinary microscopy should be utilized for preliminary examination of all specimens for these amebas. Since some strains of free-living amebas are only sluggbhly motile at 20 C, it is desirable to keep the slide at 37 C during examination. Ordinary clean, sterile slides and cover slips are used to make relatively thin preparations of exudates of body fluids or tissue emulsions. Sealing the cover slip edges with sterile mineral oil applied with a small camel's hair brush will preserve the preparation against drying. lated the N a e g l e k on agar medium with Escherichia coli without antibiotics tat 37 C.The new isolate failed to grow on the medium previously suggested by us for Hartmannella. HB-1 is virulent for laboratory animals and has ...

No abstract

No abstract