Metabolic fate of chromium compounds. I. Comparative behavior of chromium in rat administered with Na251CrO4 and 51CrCl3

Comparative metabolic fate of labelled chromium chloride and sodium chromate and interaction of these compounds in the rat liver and blood were investigated after their oral and intravenous administration. Gastrointestinal absorption of both compounds was below 1% of the oral dose, but trivalent chromium showed higher radioactivity than the hexavalent form in rats (biological half-life: CrCl3 91.79 days, Na2CrO4 22.24 days). The higher residual activity of the trivalent chromium was also observed after intravenous administration. Both forms of chromium were excreted more in the urine via the kidney than in the intestinal tract after intravenous administration. When 51CrCl3 and Na251CrO4 were injected into rats, in the time-distribution patterns of 51Cr in the organs, a significant difference was shown between oxidation states of the two compounds, especially in subcellular fractions of the liver and blood constituents. This significant difference mainly observed in the rat blood came from the fact that trivalent chromium possessed a high binding activity for transferrin in plasma, while hexavalent chromium was permeable into red cells and bound with hemoglobin.

Hemodynamic effects of sublingual nifedipine in congestive heart failure

Hemodynamic response of nifedipine in 11 patients with congestive heart failure was examined. Thirty minutes after sublingual administration of nifedipine, CI and SVI were increased together with a decrease in PAEDP and TSVRI. The increase in CI was proportional to the decrease in TSVRI. Twenty-four hours after continuous administration of nifedipine, however, six of 11 patients did not show the improvement of left ventricular function. These results indicate that sublingual administration of nifedipine is effective in the short-term therapy of the patients with a markedly decreased cardiac output and an increased systemic vascular resistance.

Ultrastructural and morphometric studies on the rat pituitary thyrotrophs and thyroid follicular cells following administration of thyrotropin releasing hormone

The pituitary thyrotrophs and thyroid follicular cells of rats were studied by electron microscopy and morphometric analysis at 5, 10, 20, 30 and 60 min after intravenous injection of 200 microgram of thyrotropin releasing hormone (TRH) and at 10 min after injection of 10 microgram TRH. Multiple granule extrusions in a group were often observed around the pituitary thyrotrophs at 5, 10 and 20 min after administration of 200 microgram TRH, as well as at 10 min after injection of 10 microgram TRH. The number of released granules reached its maximum at 10 min after 200 microgram TRH injection, but the total number of secretory granules in the cytoplasm of thyrotrophs did not show any significant variation throughout the experimental period. Percent area of the rough endoplasmic reticulum indicated the maximum value at 20 min and that of the Golgi apparatus at 10 min. These findings suggest that TRH stimulates the thyrotroph and accelerates synchronously the secretion as well as the synthesis of TSH. In the thyroid follicular cells after 200 microgram TRH injection, numerous small vesicles which might be secretory granules were found in the apical cytoplasm at 5 and 10 min. Pseudopod formation on the luminal surface and accumulation of colloid droplets and lysosome-like granules in the apical cytoplasm were most frequently observed at 20 and 30 min. The value of the mean ratio of the diameter of the colloid lumen to the cell height of follicular cells in the thyroid follicles of all experimental animals stimulated with TRH decreased much more than that of the control animals. This value may indicate the increased activity of follicular cells to reabsorb the colloid.

A rapid and precise method for the determination of vitamin D3 in rat skin by high-performance liquid chromatography

In order to develop the investigations into photobiogenesis of vitamin D3, a rapid and precise method for the determination of the vitamin in rat skin was established by using high-performance liquid chromatography (HPLC). The proposed method included saponification of small pieces of rat skin, extraction of the unsaponifiable matter and application to HPLC using "Zorbax SIL" (straight-phase) as an adsorbent and 0.5% isopropanol in n-hexane as a mobile phase. The applicable lower limit of the method was 2ng of vitamin D3/cm2 of subcutaneous tissue-removed skin and it was possible to assay a concentration higher than 2 ng/cm2. The proposed method was applied to determine the content of vitamin D3 in rat skin obtained from in vivo and in vitro irradiation experiments. In the in vitro experiment, the yield of vitamin D3 increased in proportion to the irradiation time. On the other hand, the yield in the in vivo experiment showed a proportional increase similar to the in vitro experiment until 60 min irradiation, while a nearly constant value was obtained by irradiation for longer than 60 min. When the rat skin obtained from the in vitro experiment was irradiated with monochromatic UV rays in the range s60-350 nm, the most effective wavelength for the formation of vitamin D3 was confirmed to be 303 nm, which differs from the result obtained from the experiment in a test tube (295 nm). Moreover, the yield of vitamin D3 by irradiation with UV rays below 288 nm was extremely low, which again differed from the results of a test tube experiment. These differences were thought to be due to the filter effect of the malpighian layer in the epidermis of rat skin.

Cardiac manifestations of Fabry's disease. Report of a case with pulmonary regurgitation diagnosed on the basis of endomyocardial biopsy findings

A case of Fabry's disease with pulmonary regurgitation is reported, and the cause of valvular involvement, the electrophysiological mechanism of the short PR interval, and the usefulness of the endomyocardial biopsy method in an attempt to establish the diagnosis in Fabry's disease have been discussed.