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Biomedical subjects

H Zimmermann

Publications and source records attributed to H Zimmermann.

At least 217 records · Page 12Linked to original sources
PubMed1989

Infants with posterior urethral valves: a retrospective study and consequences for therapy.

This is a report on the follow-up data of 18 patients with posterior urethral valves diagnosed during the first year of life. One infant died of progressive renal failure; a slight elevation of serum creatinine levels in three children aged 4-6 years indicated a doubtful prognosis. On initial examination, ten patients showed severe unilateral or bilateral reflux. Seven of 14 refluxing units remained non-functioning and had to be removed. Following transurethral fulguration of the valves, five infants developed unilateral or bilateral reflux which was not evident on initial preoperative voiding cystograms. In contrast to those in other series, none of these refluxes ceased spontaneously. Ureteral reimplantations were done on 11 ureters of eight patients, but regression of ureteral dilatation postoperatively remained unsatisfactory in six instances, none of whom had a true mechanical obstruction. We conclude that many of these megaloureters encountered in infants with posterior urethral valves are concomitant with profound and often irreversible damage of the ureter wall. Surgery of such ureters, therefore, should be avoided whenever feasible.

Follow-Up Studies↗
PubMed1989

Membrane proteins of synaptic vesicles and cytoskeletal specializations at the node of Ranvier in electric ray and rat.

Binding sites for antibodies against membrane proteins of synaptic vesicles have been shown to be enhanced at nodes of Ranvier in electromotor axons of the electric ray Torpedo marmorata and sciatic nerve axons of the rat, using indirect immunofluorescence and monoclonal antibodies against the synaptic vesicle transmembrane proteins SV2 and synaptophysin (rat) or SV2 (Torpedo). In the electric lobe of Torpedo, vesicle-membrane constituents occurred at higher density in the proximal axon segments covered by oligodendroglia cells than in the distal axon segments where myelin is formed by Schwann cells. Antibody binding sites were enhanced at nodes forming the borderline of the central and peripheral nervous systems. Filamentous actin was present in the Schwann-cell processes covering both the nodal and the paranodal axon segments as suggested by the pattern of phalloidin labelling. Furthermore, in rat sciatic nerve, Schmidt-Lanterman incisures were intensely labelled by phalloidin. A similar nodal distribution was found for binding sites of antibodies against actin and myosin. Binding of antibodies to tubulin was enhanced at nodes in Torpedo electromotor axons. The apparent nodal accumulation of constituents of synaptic vesicle membranes and the presence of filamentous actin and of myosin are discussed in relation to the substantial constriction of the axoplasm at nodes of Ranvier.

Animals↗
PubMed1989

Axonal transport studied in a single vertebrate neuron: the giant electromotor neuron of the electric catfish, Malapterurus electricus.

Axonal transport was studied using a single vertebrate neuron, the giant electromotor neuron of the electric catfish, Malapterurus electricus. The electric organs of this strongly electric fish are innervated by two neurons whose axons form one electric nerve each. After injection of [35S]methionine into the spinal cord at the level of the two perikarya radioactively labelled material is exported by fast flow as a small wave with a velocity of 5.8 mm/h and a somal release time of 91 min (29 degrees C). Slow flow investigated between 15 and 39 days had a velocity of 1.36 mm/d at 29 degrees C. Analysis of radiolabelled proteins by polyacrylamide gel electrophoresis revealed different patterns of labelling between slow and fast flow. The relative molecular mass of the two major proteins labelled on slow flow correspond to actin and tubulin. Labelled proteins of higher relative molecular mass may correspond to neurofilament proteins. Our results suggest that this vertebrate single-neuron and single-axon system can be used successfully for axonal transport studies.

Animals↗
PubMed1989

Intraneuronal distribution of a synaptic vesicle membrane protein: antibody binding sites at axonal membrane compartments and trans-Golgi network and accumulation at nodes of Ranvier.

The distribution of a cholinergic synaptic vesicle-specific transmembrane glycoprotein (Buckley and Kelly, 1985, J. Cell Biol. 100, 1284-1294) was investigated in the entire electromotor neuron of Torpedo marmorata using a monoclonal antibody and immunocytochemistry at the light- and electron-microscopical level (immunoperoxidase, colloidal gold). In the nerve, terminal binding of immunogold particles is restricted to synaptic vesicles. In the axon a number of additional membrane compartments like multivesicular bodies, vesiculotubular structures, lamellar bodies and electron-dense granules share the surface located synaptic vesicle-specific transmembrane glycoprotein-epitope. Membranous structures likely to represent the axoplasmic reticulum inside axons and nerve terminals are not labelled. Antibody-binding membrane compartments are accumulated at nodes of Ranvier. In the perikaryon the tubules of the trans-Golgi network as well as multivesicular bodies, lamellar bodies, electron-lucent vesicles, granules with electron-dense core and peroxisomes are labelled. Immunotransfer blots of isolated synaptic vesicles and tissue extracts of electric organ display a 100,000 mol. wt band of broad electrophoretic mobility typical of the synaptic vesicle-specific transmembrane glycoprotein. Extracts of electromotor nerve and electric lobe contain in addition a strong band at 85,000 mol. wt and a few lower molecular weight bands. We suggest that the synaptic vesicle originates directly from the trans-Golgi network. The endoplasmic reticulum is not involved in vesicle formation or retrieval. On retrograde transport the vesicle membrane compartment is likely to fuse with other intra-axonal (endosomal?) organelles.

Animals↗
PubMed1989

The synaptic vesicle membrane: origin, axonal distribution, protein components, exocytosis and recycling.

The paper discusses functional and molecular aspects of the synaptic vesicle membrane during its life cycle. The distribution of the synaptic vesicle membrane compartment in an entire cholinergic neuron is monitored using colloidal gold labelling and a monoclonal antibody against the synaptic vesicle membrane protein SV2. This provides new insights concerning vesicle origin and fate in the various compartments of the neuron. A new synaptic vesicle membrane protein (svp25) of Mr 25,000 with properties similar to synaptophysin as well as a synaptic vesicle binding phosphoprotein of the presynaptic membrane (Mr 92,000) likely to be involved in vesicle exocytosis are described. The membrane compartment recycled on induced transmitter release contains synaptic vesicle but not plasma membrane markers and encloses both newly synthesized transmitter and a sample of extracellular medium.

Animals↗
PubMed1989

[Congenital lymphangioma of the lung].

A congenital lymphangioma of the lung in a newborn is described for the first time. The aetiology and pathogenesis are discussed and various aspects of differential diagnosis considered.

Diagnosis, Differential↗
PubMed1989

Nonimmunogenic hyperthyroidism: cumulative hypothyroidism incidence after radioiodine and surgical treatment.

During 1977, 246 hyperthyroid patients were seen in our departments, 140 (57%) with nonimmunogenic hyperthyroidism (NIH)--101 with a toxic adenoma (TA) and 39 with multifocal functional autonomy (MFA). All patients but one could be followed over 9 yr, 101 after 131I treatment (RIT), another 29 after surgery (S). Ten patients were left untreated. Thirty-four treated (24%) patients died, none as a result of thyroid or post-treatment complications. There was no hyperthyroidism later than 9 mo after therapy. Only 1% (RIT) and 24% (S) were hypothyroid 1 yr after treatment. But 19% of all treated NIH patients were hypothyroid after 9 yr or at the time of their death, 12% after RIT and 41% after S. The cumulative hypothyroidism incidences 1.4%/yr for RIT and 2.2%/yr for S, were not significantly different. Out of the five survivers without RIT or S, two TA patients were hypothyroid. The effect of RIT on goiter related loco-regional complications was not worse than after S. We conclude that RIT is the treatment for NIH, leaving surgery for exceptional cases.

Adenoma↗
PubMed1989

[Proof of bioequivalence of two nifedipine preparations].

A crossover-study was performed with 20 volunteers in order to demonstrate the bioequivalence of two nifedipine preparations after single dose application. Methods for demonstrating bioequivalence were according to the APV (Arbeitsgemeinschaft für pharmazeutische Verfahrenstechnik)- and FDA-guidelines; in addition some new but less well-known biometric procedures were used. Bioequivalence could be proved for the criteria AUC, Cmax and tmax as stated in the nifedipine monograph of Zentrallaboratorium Deutscher Apotheker.

Adult↗
PubMed1988

Control of the aggregation factor-aggregation receptor interaction in sponges by protein kinase C.

By means of immunobiochemical and immunocytological techniques it was found that the aggregation factor (AF) from the sponge Geodia cydonium is stored in vesicles of spherulous cells. During the reaggregation process of dissociated cells, the AF which is present extracellularly was determined to be bound to the cell-surface-associated aggregation receptor (AR) only during the initial phase (0-5 h after addition of the AF to the single cell suspension). At later stages (20 h), the AF colocalized with extracellular structures, e.g., collagen and glycoconjugates. Immobilized to nitrocellulose, the AR, a molecule with Mr of 43.5 kDa, displayed its binding affinity to the AF only if it was isolated from early aggregates (5 h). The transition of the AF-susceptible to the AF-deficient state of the plasma membrane was mimicked in vitro by incubation of plasma membranes from early aggregates with purified protein kinase C. This conversion to the AF-deficient state could be prevented by the protein kinase C inhibitor staurosporine. Together with earlier findings, which revealed that the AR is phosphorylated by protein kinase C, we propose that in the sponge system this enzyme controls intercellular processes involved in morphogenesis.

Animals↗
PubMed1988

Monospecific antiserum against 5'-nucleotidase from Torpedo electric organ: immunocytochemical distribution of the enzyme and its association with Schwann cell membranes.

The cellular and subcellular distribution of 5'-nucleotidase in tissues of the electric ray Torpedo marmorata has been investigated by means of an antiserum raised against the native enzyme purified from the electric organ. As revealed by immunohistochemistry the enzyme is associated with the surface of the axons of the electric nerves and of spinal nerves. Using the post-embedding colloidal gold technique at the electron-microscopical level 5'-nucleotidase could be located at the plasma membrane of the Schwann cells including the myelin and the fine processes covering the terminal axon ramifications. Also the perineurial sheath of the axons inside the electric organ is 5'-nucleotidase positive. The plasma membrane of the axon and the terminal axon region or the postsynaptic membrane do not contain 5'-nucleotidase. Immunoprecipitation studies using polyacrylamide beads suggest that the ecto-Ca2+- or -Mg2+-adenosine 5'-triphosphatase previously ascribed to synaptosomes of the Torpedo electric organ is not associated with the same membranes as 5'-nucleotidase. Within the electric organ the dorsal plasma membrane of the electroplaque cell, blood capillaries and the connective tissue layer surrounding the columns of electroplaque cells also bind the antibodies. In central nervous tissue solely blood vessels show immunofluorescence. Within the electric lobe both the surface of the electromotor neurons as well as the myelinated axons giving rise to the electric nerve are negative. This also applies to the axons of the optic nerve suggesting that the antiserum is Schwann cell specific, and does not bind to a potential oligodendroglial 5'-nucleotidase. In peripheral tissue the surface of skeletal muscle fibres as well as that of individual myofibrils bind the anti-5'-nucleotidase antibodies. Our results demonstrate that the Schwann cell plasma membrane, including myelin, contains 5'-nucleotidase and that one can distinguish by means of a specific antiserum between Schwann cell and oligodendroglia plasma membranes. The functional significance of the association of 5'-nucleotidase with Schwann cells along the entire surface of axons including the synaptic region as well as with other parts of the electric tissue is discussed regarding its catalytic activity and also the possibility that this surface glycoprotein may be involved in mediating cellular interactions.

5'-Nucleotidase↗
PubMed1988

[Tracheal agenesis: which surgical measures are sensible?].

Tracheal agenesis is a rare congenital malformation. Up to now no surgical concept exists for a definitive correction. In this paper we describe our experiences with an own case and discuss the purpose and justification of temporary surgical measures.

Asphyxia Neonatorum↗
PubMed1988

Cholinergic vesicle specific proteoglycan: stability in isolated vesicles and in synaptosomes during induced transmitter release.

Exposure of synaptosomes isolated from the electric organ of Torpedo marmorata to conditions that promote the release of acetylcholine does not cause the co-release of a vesicle specific proteoglycan. Proteoglycan within synaptosomes is quite stable during various incubation conditions as measured by immune dot blotting. Isolated vesicles from Torpedo also retain their proteoglycan immunoreactivity when exposed to a variety of incubation conditions. Lysis of vesicles in H2O, treatment with pH 11.5 buffer, or exposure to high ionic strength (2 M KCl) results in the loss of acetylcholine or ATP while the proteoglycan is retained by vesicle membranes. Only treatment with Nonidet P-40 releases proteoglycan from vesicles or synaptosomes and free proteoglycan immunoreactivity is then susceptible to degradation by trypsin or heparinase. These results suggest that the proteoglycan is an integral component of vesicle membranes and is at least in the synaptosomal preparation not subject to extensive co-release with acetylcholine or ATP.

Acetylcholine↗
PubMed1987

Cholinergic nerve terminals in the rat diaphragm are chromogranin A immunoreactive.

Cholinergic nerve terminals in the rat diaphragm contain binding activity for antisera raised against either bovine or rat adrenal medulla chromogranin A. This was shown using indirect FITC immunofluorescence and rhodamine-labelled alpha-bungarotoxin to mark the endplates. No immunoreactivity was found for chromogranin B and secretogranin II.

Animals↗
PubMed1987

Purification, characterization and cellular localization of 5'-nucleotidase from Torpedo electric organ.

5'-Nucleotidase was isolated from the electric organ of the electric ray Torpedo marmorata after solubilization in Triton X-100 and deoxycholate by affinity chromatography on concanavalin A-Sepharose and AMP-Sepharose. The purified enzyme has a Km for AMP of 38 microM, with a maximal velocity of 31 units/mg of protein. Of the purine and pyrimidine mononucleotides, AMP is hydrolysed most effectively. beta-Glycerophosphate, phosphoenolpyruvate and p-nitrophenyl phosphate are not substrates for the enzyme. Adenosine 5'-[alpha, beta-methylene]diphosphate, ADP and ATP are competitive inhibitors in this order of potency. Concanavalin A inhibits enzyme activity in a non-competitive manner. Whereas Mg2+, Ca2+ and Sr2+ activate enzyme activity in the millimolar range, Hg2+, and in particular Pb2+ and Zn2+, inhibit enzyme activity. On SDS/polyacrylamide-gel electrophoresis the enzyme has an apparent Mr of 62000, whereas that of the native deoxycholate-enzyme complex is 131000. An antiserum raised against the native enzyme inhibits enzyme activity. Inhibition studies suggest the presence of tissue-specific variants of the enzyme. By immunohistochemical analysis the enzyme can be localized to the ramifications of nerve terminals in the electric organ.

5'-Nucleotidase↗