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Biomedical subjects

W Schulze

Publications and source records attributed to W Schulze.

At least 145 records · Page 8Linked to original sources
PubMed1984

Organization and morphogenesis of the human seminiferous epithelium.

The various types of human primary spermatocytes were classified by means of morphological and morphometrical studies. Based on this classification, the topographic arrangement of the spermatocyte populations in the longitudinal course of seminiferous tubules was determined. This analysis revealed human spermatogenesis be to subjected to a complex local plan of organization, which is based upon the geometry of spirals. The centers of gravity of spermatocyte populations of subsequent degrees of differentiation are arranged on helices that are contracted conically to the lumen of the seminiferous tubule. On these helices the centers of gravity of the populations diverge continuously 173.8 degrees +/- 32.4 degrees. Populations of the same degrees of development are arranged on helices with constant diameters. On these helices the centers of gravity of the populations diverge continuously 142.6 degrees +/- 14.2 degrees. The present results lead to new aspects of the kinetics and morphogenesis of the seminiferous epithelium, which can be integrated into a comprehensive biological concept.

Aged↗
PubMed1984

[Behavior of adenylate cyclase in ischemic and necrotic myocardial tissue].

The adenylate cyclase activity was determined in the left ventricles of rat hearts up to 60 min after severe ischemia and 24 hours after injection of a high dose of isoproterenol. The quantitative data show a progressive decline in the activity after 20 min of ischemia. Isoproterenol- and fluoride-stimulated activities were influenced in the same manner. The cytochemical localization showed no changes in the localization of the enzyme. But the number of cells with reaction products of the adenylate cyclase activity were decreased. The quantitative analysis of the adenylate cyclase activity in the myocardial necrosis produced by a single injection of 80 mg isoproterenol per kg body weight showed no changes in the basal activity of the enzyme however a significant reduction of the isoproterenol stimulation and a slight decrease of the fluoride-stimulated activity compared to the non-necrotic area of the same left ventricle. In cytochemical investigations no reaction of the adenylate cyclase activity was found in the centre of the necroses. But in the border zone of the basis the reaction product of the plasma membrane of the sarcolemma the main localization site of the enzyme activity was failed whereas the activity of the junctional SR was preserved. It was concluded that this activity is responsible for the unchanged basal activity in the necrotic and non-necrotic area.

Adenylyl Cyclases↗
PubMed1984

[N-quaternary derivatives of tilorone].

Tilorone (free base) reacts with alkyl halides forming quaternary ammonium salts. Bis- as well as mono quaternary compounds (2 resp. 3) were synthesized. The tilorone-bis-methoiodide (2a) was converted to several carbonyl derivatives (4 and 5). All produced compounds did not show any cytostatic activity against the murine leukemias L 1210 and P 388 in vivo. Especially the bis-quaternary derivatives 2 were highly toxic in the mouse.

Animals↗
PubMed1984

[Dorsal cleft larynx].

Until now there have been isolated reports on cleft larynx in American journals only. The cleft, which is hidden behind mucous membrane humps on the posterior larynx wall can evade diagnosis for a considerable time. Basing on a thorough examination (endoscopy, computed tomography), a case history, characterised by repeated aspiration pneumonia, and the surgical treatment of this extremely rare malformation are described.

Humans↗
PubMed1984

Adenylate cyclase activity and localization in necrotic and non-necrotic areas of rat myocardium after injection of high doses of isoproterenol.

With the help of electron microscopical cytochemical investigation, adenylate cyclase activity was shown to be strongly reduced in the necrotic tissue 24 h after isoproterenol injection. However, no changes were found in the basal activity of adenylate cyclase in this tissue region by biochemical determination, while the isoproterenol-stimulated activity was markedly reduced under corresponding conditions in the same tissue. It was suggested that these discrepancies between cytochemical and biochemical findings are due to partial solubilization of the adenylate cyclase protein by damaging the membrane structure.

Adenylyl Cyclases↗
PubMed1983

Cytochemical demonstration of guanylate cyclase activity in cardiac muscle. Preferential localization at sarcolemma and junctional sarcoplasmic reticulum.

The localization of guanylate cyclase activity was cytochemically studied in heart tissue from guinea pig and pigeon. The method, based on a lead precipitation technique with GPPNHP as the substrate, was tested by quantitative biochemical analysis. The data obtained showed that in heart homogenates GPPNHP is an acceptable substrate for guanylate cyclase. The guanylate cyclase activity of glutaraldehyde prefixed heart tissue was also measured in the presence of 2 mM lead nitrate, in 30% of the untreated control hearts. The residual guanylate cyclase responded to the addition of sodium nitroprusside with a 7-fold increase in its activity. Furthermore, the guanylate cyclase requirement for Mn2+ ions was so changed by this activator that Mg2+ was as active as Mn2+. In heart muscle cells of guinea pigs and pigeons the plasma membrane of the sarcolemma and the junctional sarcoplasmic reticulum are the precipitation sites of the reaction product. In guinea pig hearts the T-tubule membranes were likewise covered with precipitates. Sodium nitroprusside stimulation of guanylate cyclase activity was indicated by increased precipitation and by shortening of the incubation time.

Animals↗
PubMed1983

[Ergotropic efficacy of 2,3-dimethylquinoxaline-1,4-dioxide and 2-methylquinoxaline-1,4-dioxide in growing broilers using hydrocolloid-rich rations as well as broiler fattening feed].

2,3-dimethyl-quinoxaline-1,4-dioxide and 2-methyl-quinoxaline-1,4-dioxide proved to be ergotropic in the feeding of a hydrocolloid ration as well as of a broiler fattening feed. They are at least equal to Nitrovin. The ergotropic effect of the hydrocolloid ration was higher than that of the conventional ration. For this reason methylated quinoxaline-1,4-dioxides are considered as belonging to the intestinal stabilisers. They increased nutrient and energy retention and decreased feed efficiency by approximately equal to 10%. Residues in the liver, the kidneys and the intestines could only be detected after 10 times the ergotropic amount.

Animal Feed↗
PubMed1983

[Ultrastructural localization of nucleoside phosphatase activity in the thymocytes of rats].

A comparative electron histochemical investigation was made of ATPase and 5'-nucleotidase activities in isolated cells and in cryostate sections of the rat thymus after various pretreatment. A most optimal demonstration of intracellular ATPase and 5'-nucleotidase activities was possible in non-fixed isolated cells whose cytoplasm was partially or completely destroyed in the process of homogenization. ATPase and 5'-nucleotidase activities were revealed in the nuclear chromatin and in interchromatin ribonucleoproteins, perinuclear space, endoplasmic reticulum and Golgi complex. ATPase activity on the plasma membrane was revealed in the best way in isolated cells after glutaraldehyde prefixation.

5'-Nucleotidase↗
PubMed1983

[Golgi apparatus and T-tubules in cultured myocytes of rat hearts].

The cytochemical-ultrastructural study of rat ventricular cells grown in tissue culture supported the findings of Kasten (1971) on the existence of a special type of Golgi apparatus around the base of the nucleus of the myocardial cell. TPPase and ATPase activity are also found at the subsarcolemmal cisterns and the lateral vesicles of the sarcoplasmic reticulum. Therefore, well developed triads and diads are visible. These structures, however, require the existence of T-tubules in the cultured neonatal myocardial cells. Up to now the presence of T-tubules in early cultures of rat myocytes was still controversy. The demonstration of the T-tubules completes our knowledge of cultured cardiac myocytes and should be taken into consideration in further biochemical and physiological studies with this in vitro model.

Animals↗
PubMed1983

[Antineoplastic and curative antileukemic activity of 1,4-benzoquinone guanylhydrazone thiosemicarbazone and its hydrochloride on in vivo murine models].

By means of four murine models, the authors demonstrated in vivo that 1,4-benzoquinone guanylhydrazone thiosemicarbazone (1), which is known to be antimicrobially active, and its hydrochloride (2) exert an antineoplastic effect. In leukaemia P 388 and leukaemia L 1210 both compounds had a curative action already after four oral administrations. The "cured" animals were resistant or cross-resistant to further transmissions of leukaemia. The resistance was transmissible by splenocytes.

Animals↗
PubMed1982

Cytochemical localization of guanylate cyclase in cardiac muscle.

With the help of a cytochemical method based on the lead precipitation technique, the localization and distribution of guanylate cyclase in heart tissue from guinea pig and pigeon were studied. In heart muscle of both animals, the plasma membrane of the sarcolemma and the junctional SR are the precipitation sites of the reaction product. In guinea pigs the T-tubule membranes were also covered with precipitates. Presence of sodium nitroprusside strengthens the precipitates, indicating an activation of the enzyme; Mn2+ ions were essential for an optimal reaction. Quantitative measurements show that GMP-P(NH)P instead of GTP was accepted by the enzyme as substrate; after prefixation with 2% glutaraldehyde and incubation with lead ions, the enzyme activity was retained to about 30% of controls. Sodium nitroprusside greatly increases the retained enzyme activity.

Animals↗
PubMed1982

Cytochemistry of adenylate cyclase. Quantitative analysis of the effect of cytochemical procedures on adenylate cyclase in heart tissue homogenates.

The effects of different preparative and cytochemical procedures on adenylate cyclase (AC) activity in heart muscle homogenates were studied by quantitative analysis. We were mainly concerned with perfusion prefixation, using glutaraldehyde (GA) with and without DMSO, and with the influence of cytochemical incubation with lead ions as the capture reagent. Furthermore, we measured the direct effect on the AC activity of lead, cobalt, and strontium ions in prefixed heart homogenates. We also studied the influence of phosphatidylinositol and 2',5'-dideoxyadenosine. The following results were obtained: 1. Perfusion fixation using 2% GA buffered with cacodylate reduced the AC activity by about 20%. After the entire cytochemical procedure was finished, 20% of the original AC activity was still present. Stimulation by epinephrine, histamine and fluoride, which increased the activity of AC two or three times in our experiments, was only slightly reduced by the cytochemical treatments. 2. Lead ions (2 mM), added to the biochemical assay without chelating compounds, reduced the AC activity about 90%. 5 muM phosphatidylinositol stabilized the fluoride- and hormone-sensitive AC activity. 3. Co2+ also reduced the AC activity, though less than Pb2+. Sr2+ had no effect on the basic activity of the AC but had a slightly inhibitory effect on the hormone and fluoride stimulation. 4. 5% DMSO added to the fixative had no influence on the basic activity of the AC. However, this solvent definitely reduced the level of stimulation by fluoride and guanine nucleotide plus hormones. 5. A potential inhibitor of enzyme activity and of the hormone- and fluoride-sensitive AC was the adenosine derivative, 2',5'-dideoxyadenosine. This compound, at a concentration of 10(-3) M, inhibited all AC activity in the heart homogenates.

Adenylyl Cyclases↗
PubMed1981

Multinucleate Sertoli cells in aged human testis.

The present investigation documents morphological characteristics of human Sertoli cells of aged males. Testicular material was obtained from 35 patients (age 62-84 years) with carcinoma of the prostate who had received no previous anticancer therapy. As revealed by light and electron microscopy the appearance of the germinal epithelium showed great individual variations. In all cases examined, however, the occurrence of multinucleate Sertoli cells was a common finding. In seminiferous tubules with intact spermatogenesis these cells closely resembled the normally occurring variants, whereas they displayed features reminiscent of immaturity in the absence of germ cells. It is hypothesized that the nuclei of Sertoli cells in the special situation of aging may resume the capacity to divide, an ability normally restricted to immature cells. Thus, mitosis without subsequent cytokinesis might be an explanation for the formation of multinucleate Sertoli cells.

Aged↗
PubMed1981

Ultracytochemical localization of adenylate cyclase activity in rat thymocytes.

Ultrastructural localization of adenylate cyclase (AC) activity was investigated in suspensions of unfixed isolated rat thymocytes using a medium containing 0.6 mM 5'-adenylylimidodiphosphate (AMP-PNP) as a substrate, 10 mM MgSO4 as an activator, 5 mM theophylline as an inhibitor of 3' 5'-AMP-phosphodiesterase and 2 mm lead nitrate as a capturing agent. AC activity was demonstrated in plasma membrane, perinuclear space, endoplasmic reticulum, Golgi complex, centriole microtubules and mitochondria. AC was activated with 10(-4) M adrenaline in the presence of 5'-guanylylimido-diphosphate (GMP-PNP) as well as with 10(-2) M NaF. In the cells incubated in a medium devoid of theophylline and containing 5'-AMP instead of AMP-PNP, 5'-nucleotidase activity was observed in the same cell structures as AC activity, Hydrolysis of 5'-AMP in the nucleus was much stronger than that of AMP-PNP. 10 mM NaF markedly inhibited hydrolysis of 5'-AMP in all cell structures. No staining was observed with 2 mM beta -glycerophosphate as a substrate. Incubation of unfixed thymocytes in media containing AMP-PNP, 5'-AMP or p-nitrophenyl phosphate, but not beta -glycerophosphate, induced both in the nucleus and in the cytoplasm in some cells an appearance of a transitory reticular formation consisting of about 303nm thick strands which could penetrate the nuclear envelope and plasma membrane and form connections with adjacent cells. The transitory reticular formation seems to belong to the cytoskeleton and to be involved in cell aggregation.

Adenylyl Cyclases↗