圈养大熊猫粘液排泄现象的观察

大熊猫(Ailuropodamelanoleuca)是中国特有的珍稀动物,它们以高纤维含量的竹子为主食,但却具有与食肉动物相似的消化系统结构,为适应高纤维的食物,它们又形成了与食竹相适应的消化生理特点。其整个消化道内膜上粘液腺丰富,在野外,这些粘液腺的分泌物包裹于大熊猫所摄食的竹茎、     

Renal aluminum excretion

Urinary aluminum (Al) excretion was studied in humans with normal and impaired renal function. Al was measured by atomic absorption spectrometry. In healthy volunteers (n=50), renal Al excretion was 12.2±8.5 μg/24 h. Two patients on plasma exchange therapy with normal renal function and an inadvertent load of 870 and 388 μg Al/treatment showed a 23 and 14% positive balance until next treatment.     

Technetium-99m distribution into Klebsiella pneumoniae.

Bacteria labelled with radionuclide has been the subject of much investigation and has been applied in microbiological research. Technetium-99m (99mTc) may be an alternative radionuclide for the labelling of bacteria employed in various microbiological procedures. This radionuclide is easily available, is not expensive and presents important physical and biological characteristics. 99mTc-labelled bacteria are stable and their cell viability and biological properties are not modified. Study of the distribution of radioactivity in 99mTc-labelled Klebsiella pneumoniae cultures, after homogenization and differential centrifugation of the cells fractions, showed that this radionuclide was present inside the cell, mainly in a ribosomal fraction. Treatment of these fractions with enzymes and detergent revealed a high sensitivity to pronase and Triton X-100. After phenol extraction, a large percentage of radioactivity was detected in the phenol phase. Treatment of the soluble fraction with trichloroacetic acid at different temperatures showed that the concentration of 99mTc in the precipitate was lower at 100 degrees than at 4 degrees C. These results suggest that 99mTc binds mainly to the proteins in Klebsiella pneumoniae.     

Preliminary observations on Chrysochromulina Mactra sp. nov.

Salient features of interest concerning this new species include its large cell size, characteristic scales, bulging pyrenoids and aspects of its development and geographical distribution. The scales, described in some detail, are individually visible with the light microscope and of two types. The outermost scales are tub- or beaker-shaped and the under scales rimless plates. In both cases their thin texture, surface patterning and appearance in section permit an interpretation to be put forward in terms of relatively simple modifications of two-layered rimless plates. The relevance of these findings to understanding of some living and fossil forms is discussed in a preliminary way.     

Renal amino acid excretion and aging

The urinary excretion and serum concentration of amino acids were studied in 62 healthy individuals aged 15 to 70 years. In elderly subjects (61-70 years), it was found that renal amino acid clearance per 100 ml GFR (fractional excretion, FE) rose significantly in the following amino acids: CYS, VAL, MET, ILE and LEU. Since the serum concentrations of these amino acids showed no significant changes, but the GFR was reduced, it can be concluded that the raised FE of these amino acids was due to a decrease in their effective tubular reabsorption. A significant correlation was found between FENa and FE of most amino acids including those mentioned above. The findings support the assumption that changes in tubular Na+ transport probably participate in the changes of tubular amino acid transport in elderly individuals.