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Biomedical subjects

H Schubert

Publications and source records attributed to H Schubert.

At least 19 recordsLinked to original sources
PubMed1992

Binding characteristics and functional G protein coupling of muscarinic acetylcholine receptors in rat duodenum smooth muscle membranes.

The non-selective labelled antagonist [3H]N-methyl-scopolamine ([3H]NMS) was used to identify muscarinic acetylcholine receptors in rat duodenum smooth muscle membranes. Saturation and kinetic experiments revealed a binding site with a KD-value of 0.2-0.3 nmol/l and a receptor concentration (Bmax) of 100 fmol/mg protein. The affinities of eight selective muscarinic antagonists were determined and compared with those at M1 (rat cerebral cortex), M2 (rat heart), M3 (rat submandibular gland) and M4 (data from Dörje et al. 1991) receptors. The "M2-selective" agent AF-DX 116, the group of "M2/M4-selective" compounds himbacine, AF-DX 384, AQ-RA 741 and methoctramine but also the "M3-selective" HHSiD showed affinities corresponding to M2 and/or M4 sites. The intermediate affinity of 4-DAMP favours a mixed M2/M4 receptor population mainly containing M2 receptors. Two compounds, pirenzepine and AQ-RA 741, displayed biphasic displacement curves indicating the presence of a small population of putative M1 receptors. The rat duodenum antagonist binding profile, however, is not consistent with the presence of M3 receptors. We further demonstrate a concentration-dependent stimulation of [35S]GTP[S] binding to duodenal G proteins by the muscarinic agonist oxotremorine. Estimation of the binding parameters of GTP[S] in absence and presence of oxotremorine provided evidence for a catalytic activation of G proteins by agonist-activated muscarinic receptors in rat duodenal membranes and a strong signal amplification on the G protein level.

Animals↗
PubMed1992

[Insulin-like growth factor I--a connecting link between nutrition and growth].

The influence of an increasing protein supply in combination with soybean oil upon the IGF-I concentration in the serum in correlation with growth was measured on 8 x 10 male Wistar rats. With a casein content of 0% in the food, the IGF-I level was 0.13 +/- 0.02 rU/ml. An IGF-I plateau of 0.74 +/- 0.07 rU/ml was reached at some 15% casein. The additional application of 3% soybean oil increased the IGF-I concentration significantly (P less than 0.01) up to 0.95 +/- 0.16 rU/ml. The investigations show a specific increase of the IGF-I synthesis by the addition of oil, which is paralleled by a further stimulation of the growth of the rats. The nutrition-dependent IGF production in the peripheral tissues (mainly liver) represents the connection link between the growth hormone axis (genetically potential growth) and the growth realizable depending on the supply with nutrients.

Animal Nutritional Physiological Phenomena↗
PubMed1992

Histochemistry of the porcine pilosebaceous unit.

The present study describes lectin and immunoreactivity in the pilosebaceous unit of porcine skin. Complex carbohydrates of mucin and biantennary Man/Gluc types were distributed among hair follicle epithelia (hair root sheaths, cuticula, shaft, and shaft matrix). Sebaceous glands expressed biantennary Man/Gluc carbohydrates and GalNAc residues. The expression of simple-type and epidermis-like keratins was confirmed by immunohistochemistry with monoclonal antibodies. Filaggrin-positive cells were found in the keratinizing zone of Henle's layer in anagen follicles. The innermost layer of the outer hair root sheath was stained with antibodies against the epidermal growth factor-receptor, keratin 10 and Ki67 antigen. The differences to humans were remarkably small.

Animals↗
PubMed1992

Tissue expansion in pig skin--a histochemical approach.

In the present study, a porcine model for controlled skin expansion was investigated to improve our understanding of epidermal and vascular responses following stretching. The model is of outstanding importance not only for the clinical use of tissue expansion but provides interesting data for skin physiology and oncology, too. Thirteen out of 15 animals, who underwent silicone tissue expander implantation showed good clinical results. In all of them, skin biopsies were taken at the end of a controlled tissue expansion procedure (final expander volumes 350 or 500 ccm): one tissue specimen was obtained from the centre of the expanded skin area and a second from the neighbouring but nonexpanded skin. The tissue specimens were immediately frozen in liquid nitrogen and processed to 4 microns thick acetone-fixed frozen sections. Lectin histochemistry and immunohistology were performed using the following techniques: direct and indirect immunofluorescence technique (DIFT, IIFT), immunoperoxidase technique (POX) with either 3,3'-diamino-benzidine (DAB) or 3-amino-9-ethyl-carbazole (AEC). The histochemical findings were supplemented by measurements of the number of vital epidermal cell layers, the epidermal thickness (microns), and the papillary vascular count per visual field. There was a significant diminuation of the vascular count (mean +/- S.D. = 55.0% +/- 12.5%; U-test: p less than 5%). By immunohistochemistry, a loss of the basal cell reactivity for the following antibodies was noted: ACAM (against calmodulin), K 8.12 (against keratins 13 +/- 16) and A51-B/H4 (against keratins 8, 14, 18). There was a remarkable increase of filaggrin expression in the uppermost spinal cell layers in expanded skin, which was most pronounced in those specimens with the shortest interval to the last fluid injection into the expander. We gained no evidence for alterations of the expression of suprabasal epidermal keratins, lectin binding sites (UEA I, PNA, ConA, WGA), and vascular lectin- and immunoreactivity due to tissue expansion. The subdermal capsule, which had formed around the silicone expander, was strongly vimentin-reactive. In conclusion, controlled tissue expansion is capable to change the basal cell phenotype--a feature which is shared with a number of conditions with increased proliferative activity and with the epidermis covering different skin tumours. The regular expression of suprabasal keratins and epidermal lectin binding sites provides evidence for a normal epidermal cell differentiation. Furthermore, the porcine skin is a reliable model for studying physiology and pathophysiology of human skin.

Animals↗
PubMed1992

[Experimental studies on tissue expansion in reconstructive surgery].

In the present study, a porcine model for controlled tissue expansion was investigated under the conditions or formation of extreme enlarged randomized flaps. The circulatory disturbances and necrotizing processes to be expected were evaluated immediately after flap formation by intravenous injection of fluorescein dye to predict the surviving area. Lectin histochemistry and immunohistology were performed using either the direct and indirect immunofluorescence technique (DIFT, IIFT) or immunoperoxidase techniques (POX). Over all, the expanded randomized flaps healed without complications in all animals. The acute randomized flaps showed clear necroses already after 10 days. In the thoracic area they averaged 60.3% (SD = 8.17%) and in the pelvic area 47.32% (SD = 14.11%) of the flap. The use of the fluorescein dye test in the present experiment demonstrated that the flap surviving area is significantly greater than the flap staining area. The regular expression of suprabasal keratins and epidermal lectin binding sites provides evidence for a normal epidermal cell differentiation.

Animals↗
PubMed1992

[Drug modification of post-traumatic edema of the extremities by the proteinase inhibitor aprotinin. An animal experiment study].

Posttraumatic edema remains a serious problem in traumatology. Unrecognized or improperly treated, edema poses a threat to the survival of any extremity, particularly the hand, where a number of intricate functional structures are at stake. This study, as well as other recent clinical and experimental work, show that aprotinin, a proteinase inhibitor, is valuable in the treatment of posttraumatic edema, provided it is given as early as possible and in an adequate dosage.

Animals↗
PubMed1991

A double-blind comparative multicentre study of controlled-release remoxipride, immediate-release remoxipride and haloperidol in schizophrenia.

A double-blind multicentre study comparing the efficacy and safety of remoxipride in controlled-release formulation (REM-CR), given once a day, and immediate-release formulation (REM-IR) and haloperidol, given twice daily, was conducted in patients with schizophrenic illness. In total, 150 inpatients were randomized: 49, 51 and 50 in the REM-CR, REM-IR, and haloperidol groups, respectively. The mean daily dose of REM-CR during the last week of treatment was 361 mg, that of REM-IR 332 mg. In the haloperidol group the corresponding dose was 12.5mg per day. The study treatment period was four weeks. The median BPRS total score was 37.5 in the REM-CR group at start of treatment, and 14.5 at last rating (n = 38). For the REM-IR group and the haloperidol group the corresponding figures were 36.0 and 38.0 at start of treatment and 18.0 (n = 43) and 16.5 (n = 40) at last rating. No statistically significant differences were found between the treatments. Therapy-emergent extrapyramidal symptoms (Simpson & Angus rating scale) were significantly (p less than 0.05) more frequent and more severe during haloperidol than during REM-CR and REM-IR treatment, despite significantly higher concurrent use of anticholinergic drugs in the haloperidol group.--REM-CR was comparable in efficacy and tolerability to REM-IR. The tolerability profile favoured both remoxipride formulations over haloperidol. Evaluation of the clinical chemistry, haematology, and cardiovascular data showed no clinically significant deleterious effects on any organ system for either drug.

Adolescent↗
PubMed1979

Synthesis of arachidonic acid in the human placenta in vitro.

The syntheses of arachidonic acid and total fatty acids were measured in human placentas at the end of the first trimester and at term using 14C-acetate in in vitro incorporation experiments. The rates of arachidonic acid synthesis were determined to be 0.70 (first trimester) and 0.64 (term) mumol/h/100 g of placental tissue. The calculated rates of total fatty acid synthesis amount to 0.5 (first trimester) and 0.6 (term) mumol palmitate-equivalents/h/100 g. The results suggest that the human placenta seems to be not dependent on maternal arachidonic acid. Near term the placenta even could be source of arachidonic acid.

Arachidonic Acids↗
PubMed1979

[The allergenic nature of p-tert-butylphenolformaldehyde resin].

Until now allergic contact dermatitis to polychloroprene glues was thought to be caused by uncondensed p-tert.-butylphenol (monomer) or by the p-tert. burylphenol formaldehyde resin molecule (polycondensate) as allergens. This opinion could not be verified. We found the following two contact allergens: 2-hydroxy-5-tert.-butylbenzyl alcohol and a four nuclear-condensate from four p-tert-butylphenol molecules linear combined by methylene bridges.

Adhesives↗
PubMed1979

[Paraproteins in dermatological patients (author's transl)].

Report on paraprotein-cases in a dermatological totality of patients during a six years period. Among 860 seras we found 22 cases with paraproteins. Except IgE-paraprotein all other paraproteinclasses were found in their natural multidy. In 2 cases we saw Bence-Jones-protein, in an other case a very rare combination of IgD-paraprotein with Amyloidosis cutis nodularis atrophicans Gottron. Diseases with sure or probable autoimmune background, i.e. diseases of the vessels with a possible dependence from cold and malignant tumours were on the top of paraproteinemia. 4 of 22 patients died during a 3 years' period after detection of paraprotein. Common clinical and paraclinical signs and symptoms of paraproteinoses are collected in a special table.

Adolescent↗