Chromogenic Limulus amoebocyte lysate (LAL) tests were evaluated for measuring endotoxic activity in faeces of mice from different microbiological environments. Faeces of BALB/c mice from germ-free (GF), specific-pathogen-free (SPF) and conventional (CV) colonies had no inhibitory activity on the test reaction. GF and SPF faeces had heat-labile non-specific amidase activity which gave false-positive reaction, while CV did not. GF faeces had a heat-stable non-endotoxic effect on the LAL system. Average endotoxin levels in faeces of GF, SPF and CV mice were 0.2, 0.8 and 17 to 24 micrograms/g wet weight, respectively. Results suggest that the microbiological status of mice influences not only the faecal endotoxin level but also the specificity of the test reaction.

Amidohydrolases↗

PubMedDate not supplied

Optimized scanning conditions of high resolution CT in the follow-up of pulmonary emphysema.

PURPOSE: To address the optimal scanning condition of high resolution computerized tomography from the perspective of minimizing exposed dose. METHOD: The influence of the electric current, the slice number, and the slice thickness on precise percent ratio of the low attenuation area to whole lung field (LAA%) of chronic obstructive pulmonary disease patients was examined. The standard conditions were 250 mA, 3 slices, 2 mm slice thickness, and a varied parameter. RESULTS: In cases showing an LAA% less than 30, LAA% obtained by < or =150 mA were significantly larger than those by 250 mA. The mean LAA% with 3 and 10 slices were well correlated and the correlation with lung function was similar. The correlation of LAA% with lung function was approximately the same between the 2 and 5 mm slice thicknesses. CONCLUSION: The electrical current must be > or =200 mA, and 3 slices and 2 mm slice thickness are appropriate.

Electricity↗

PubMedDate not supplied

Adherence of human spermatozoa to trypsin-modified hamster ova.

Human spermatozoa do not attach to the zona pellucida of other species because of their high specificity compared to that of other animals in recognizing the zona pellucida. This study describes the recognition mechanism of human spermatozoa through trypsin treatment of the ovum of human and other species. This research has revealed two findings: (1) The "lattice-like" structure, the surface of the zona pellucida of the hamster ovum, was lost and became a uniformly coarse and flat structure. More than 200 human spermatozoa attached to it. The number of attaching spermatozoa increased significantly along with the prolongation of the incubation period and in direct dependence on the spermatozoa concentration. (2) Human spermatozoa did not attach to the zona pellucida of mouse, rat, and human ovum. This result confirmed that human spermatozoa attach to hamster ovum if modified with trypsin.

Animals↗

PubMedDate not supplied

Metabolism of strychnine in vitro.

The in vitro metabolism of strychnine was studied in the 9000g supernatant fractions from rat and rabbit livers. The metabolism was markedly inhibited by cytochrome P-450 inhibitors, SKF-525A and n-octylamine, but only slightly by a microsomal FAD-containing monooxygenase inhibitor, methimazole. Five metabolites formed in vitro with rabbit liver were isolated and purified by Sep-Pak C18 cartridge chromatography and preparative TLC. Three of them were identified as 2-hydroxystrychnine, strychnine N-oxide, and 21 alpha, 22 alpha-dihydroxy-22-hydrostrychnine by comparison with their authentic samples by means of UV, NMR, and mass spectrometries. An additional two metabolites were tentatively identified as strychnine 21,22-epoxide and 11,12-dehydrostrychnine by spectral measurements. Four of these metabolites, with the exception of 2-hydroxystrychnine, were novel metabolites of strychnine. The in vitro formation of these metabolites by rabbit liver was determined by HPLC after partial purification. The major identified metabolite was strychnine N-oxide, which accounted for approximately 15% of the metabolized strychnine. All the other metabolites accounted for less than 1%. The presence of a larger quantity of other metabolites which have been neither isolated nor identified was also suggested.

Animals↗