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K Unsicker

Publications and source records attributed to K Unsicker.

At least 253 records · Page 14Linked to original sources
PubMed1975

Fine structure of the male genital tract and kidney in the Anura Xenopus laevis Daudin, Rana temporaria L. and Bufo bufo L. under normal and experimental conditions.

The ultrastructure of the main cellular components of testicular interstitial spaces in three Anuran species was studied during two short periods of the seasonal cycle and after treatment with 5- and 6-hydroxydopamine (5- and 6-OHDA). In early December when seminiferous tubules are completely filled with resting spermatozoa in Rana, Leydig cells display a well developed smooth- and rough-surfaced ER, numerous granular vesicles being untypical of Mammalian Leeydig cells, metochondria with tubular cristae and only few lipid droplets. In late April shortly after spermiation has occurred in most animals studied Leydig cell exhibit a low degree of activity as shown by the presence of numerous large lipid inclusions, reduced amounts of ER and granular vesicles, but increased numbers of dense bodies. In addition, a few rather undifferentiated cells are observed. In principle, the same differences between winter and late spring Leydig cells are seen in Bufo, although the smooth-surfaced ER which is partly arranged in whorls is much more pronounced in this species whereas granular vesicles are lacking. In December intertubular spaces display a few mitotic figures of Leydig cells. In Xenopus no obvious seasonal changes are observed in Leydig cells. As in Rana, there are numerous granular vesicles. The agranular ER is moderately developed. Intratesticular seminal excretory ducts consist in all three species studied of very low differentiated cells being almost completely filled with filaments (equivalent-100 A). Seasonal changes do not seem to occur. Morphological equivalents for secretory or resorptive processes are neither observed in early December nor in late April around the time of spermiation (in Rana and Bufo). At the connections site of seminiferous tubules and excretory ducts a basal laminal labyrinth is commonly observed. In Xenopus smooth muscle cells from an incomplete sheath around seminiferous tubules and are also uniformly distributed in the intertubular spaces without any obvious relationships to vessels. Rana and Bufo lack a peritubular contractile cell layer. After application of 5- and 6-OHDA (5-OHDA: three injections of 200 mg/kg at 12 hr intervals; 6-OHDA: three doses of 100-150 mg/kg on three consecutive days) cytoplasmic inclusion bodies with lamellar and crystalloid internal patterns develop in Leydig cells from lysosome-like structures. In addition, formation of dense bodies from mitochondria is seen in a few instances. The significance of these alterations is discussed.

Amphibians↗
PubMed1975

Acute changes of the Na-K-ATPase-activity in plasmamembranes of the isolated, cell-free perfused rat kidney.

The Na-K-ATPase-activity of the isolated, cell-free perfused rat kidney was investigated. Na-load and perfusion rate could be varied independently. The ATPase-assay was carried out on plasmamembranes (700-1200 g fraction) isolated and purified after 60 min perfusion. Both the specific Na-K-ATPase-activity and the fractional Na-reabsorption showed an indirect correlation with the Na-load as well as with the perfusion rate. The Na-K-ATPase-activity of plasmamembranes obtained from the isolated kidney at physiological Na-load fits well to control values prepared from unperfused control kidneys. The present data are in accord with the results of earlier micropuncture experiments, where acute saline loading diminished the rate of Na-absorption.

Absorption↗
PubMed1975

[Function and morphology of isolated rat kidney following cellfree perfusion with various plasmaexpanders (author's transl)].

Isolated arteficially perfused rat kidneys prepared as described by Franke et al. (1971) were perfused for 60 min with solutions of Haemaccel, Dextran 40, Pluronic-F-108, or hydroxy-aethyl starch in a single pass system. The glomerular filtration rate (GFR) of the Haemaccel or Dextran 40 perfused organs amounted during the first 30 min to 0.58 ml X g-1 X min-1 and 0.47 ml X g-1 X min-1 respectively. Using Pluronic-F-108 or hydroxy-aethyl starch GFR rose to 0.94 ml X g-1 X min-1 and to 0.85 ml X G-1 X min-1. With Haemaccel or Dextran 40 solutions a mean tubular Na-reabsorption of 75.4 mumol X g-1 X min-1 and of 59 mumol X g-1 X min-1 respectively was determined. Employing Pluronic-F-108 or hydroxy-aethyl starch a mean sodium net transport of 92.6 mumol X g-1 X min-1 in both experimental groups was obtained. The differences described in the functional capabilities of Haemaccel or Dextran 40 and of Pluronic-F-108 or Hydroxyethyl starch perfused kidneys are in good accordance with morphological changes in the ultrastructure. The most striking morphological deviations were found in proximal tubules of those kidneys perfused with Haemaccel solutions. On the other hand after perfusion with hydroxyethyl starch only very few morphological alterations could be detected.

Animals↗