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Biomedical subjects

J Weis

Publications and source records attributed to J Weis.

At least 127 records · Page 7Linked to original sources
PubMed1993

Perineurial cells are the first to traverse gaps of peripheral nerves in silicone tubes.

Silicon tubes were used to study the outgrowth and differentiation of the perineurium around the cord bridging the gap between the proximal and distal stumps of the transected sciatic nerve of rats. The sequence of events was investigated at time intervals 3, 7, 12, 18, and 21 days after surgery. Although similar tubulation systems have been used to investigate various aspects of peripheral nerve fibre regeneration, the present study shows for the first time with electron microscopic and immunocytochemical methods that a primitive perineurium bridges the gap as the initial cellular element. This perineurium develops from outgrowing fibroblasts as early as 7 days post surgery, forming a tube which is used as a guiding structure for subsequent cellular elements. The proximal and distal perineurial tubes join between 12 and 18 days after surgery thus representing the first connection between the proximal and distal nerve stumps. Blood vessels, Schwann cells, and axons appear to follow in this sequence.

Animals↗
PubMed1993

Renaut bodies contain elastic fiber components.

Renaut bodies (RB) are fusiform endoneurial structures preferentially found at sites of nerve entrapment, often occupying more than 30% of the cross-sectional area of a nerve fascicle. Their composition and significance, however, are still incompletely understood. In this study, further evidence for the link between the appearance of RB and nerve entrapment is presented. Reanaut bodies were already found at the age of 1 year in the median nerve at the level of the wrist, i.e. in the carpal tunnel, a possible site of entrapment. Here, their number increased with age. Renaut bodies were absent, however, in fetal nerves at this site. Many of the cells in RB resembled perineurial cells or pericytes. They were stained with antibodies against vimentin and epithelial membrane antigen and were partially covered by a basal lamina reactive with antibodies against collagen IV, laminin, and s-laminin. Focally accumulated filaments and bundles of 30-40 nm collagen fibrils were major extracellular components of RB. The diameter of the filaments (8-12 nm) corresponded to the size of the microfibril, i.e. the oxytalan component of elastic fibers. Renaut bodies were intensely stained with antibodies against these microfibrils and several types of collagen glycoproteins. On the basis of these results, we conclude that RB are composed of cells that show perineurial differentiation. These cells produce an extracellular matrix highly enriched in elastic fiber components.

Adult↗
PubMed1993

[Experience in psychosocial management of cancer patients undergoing bone marrow transplantation].

Psychosocial care of cancer patients undergoing bone marrow transplantation. During the last years bone marrow transplantation (BMT) has emerged as a treatment of choice especially for cancer diseases of the haemopoietic system as well as for certain solid tumours. BMT is a very invasive treatment with high dose chemotherapy and total body irradiation, which is accompanied by special psychosocial strains for the patient. Therefore psychosocial care during the acute treatment is needed. In this paper a psychosocial liaison service in a BMT unit as part of a comprehensive psychosocial care on different oncology wards of an acute clinic is presented. Based on a systematic clinical documentation of the psychosocial interventions the practice and problems of the psychosocial care are described. Apart of common problems of psychosocial liaison services known from the literature the experiences show special demands reflecting the special environment of the treatment setting. These problems are discussed with regard to the different target groups (patients, relatives, medical staff). Following the reported experiences some proposals concerning structure and integration of psychosocial care in an BMT unit are given.

Adaptation, Psychological↗
PubMed1993

[Experiences with psychosocial liaison service on oncologic units of an acute clinic].

Within the last years psychosocial care in acute medicine has become more and more important. Therefore different conceptional structures are discussed to optimize the integration into primary care medicine, especious psychosomatic or psychosocial consultation and liaison services. Having resumed the concepts and practice of psychosocial care in oncology this paper describes a psychosocial liaison service accompanying a research project in psychooncology. The representation focuses the experience with psychosocial care of cancer patients over the last three years. Based on a systematic clinical documentation the activities are described with regard to psychosocial indication, patient assignment, patients needs during acute treatment and the different kinds of psychosocial interventions applied. The experiences are evaluated regarding the target groups (patients, relatives, medical staff) and associated problems of cooperation and organisation met with medical staff. Finally needs, possibilities and limits of psychosocial liaison services are discussed comparing the experiences with others reported in the literature.

Adaptation, Psychological↗
PubMed1992

Rat gastric relaxation induced by stimulation of endothelin-1 selective receptors.

We have investigated the smooth muscle activity of ET-1 and ET-3 on rat fundus strips in vitro as well as the effects of the peptides on gastric motility in vivo. In the isolated tissue with no precontraction ET-1 and ET-3 were potent spasmogens which produced half maximal contractions at concentrations 4.5 and 8.0 nM, respectively. In contrast, under conditions where the isolated tissue was precontracted to approx. 50% of maximum by prostaglandin E2, ET-1 dose-dependently (5 x 10(-10) - 10(-8) M) and temporarily relaxed the fundus strip, whereas ET-3 further increased the contraction. The relaxing capacity of ET-1 was absent when the tissue was precontracted by potassium yet was resistant to pretreatments with tetrodotoxin, capsaicin, propranolol, indomethacin, NG-methyl-L-arginine or glibenclamide. In addition in vivo ET-1 and ET-3 (less than 1 nmol/kg) showed opposite effects on gastric motility as the former reduced basal tonus and spontaneous activity, whereas the latter increased the motor activity of the gastric ventricle. The results support the notion that ET-1 may induce gastric relaxation by stimulation of selective receptors whereas stimulation of nonselective receptors may promote gastric smooth muscle contraction.

Animals↗
PubMed1992

[Changes in occupational status following cancer. An empirical study on occupational rehabilitation].

The importance of vocational integration has increased during the last years, whereas an analysis of the literature shows, that research in this field has been neglected especially in german speaking countries. This study investigates the situation and the problems of vocational integration after cancer. 380 former patients with different diagnoses treated in a university medical center have been asked by a self developed questionnaire for their experiences in treatment and medical rehabilitation, their actual impairment in physical and vocational functioning, their estimation of rehabilitation success, their actual employment problems and the changes of job conditions due to cancer. As the results show, more than one third of the sample returned to work often reducing working time or changing their job. Especially older patients with worse prognoses have been retired early. Special programs of vocational rehabilitation are not used by patients we examined, whereas programs of medical rehabilitation are used showing great differences between diagnostic groups. The return to work is influenced by age, tumor localisation, prognosis and the former status in job. The results are discussed with regard to the problems of psychosocial rehabilitation of cancer patients.

Adaptation, Psychological↗
PubMed1992

Evaluation of the co-mutagenicity of ethanol and delta 9-tetrahydrocannabinol with Trenimon.

The mutagenic potential of chronic treatments of male CF-1 mice with ethanol and delta 9-tetrahydrocannibinol (THC), and their comutagenic potential with a known mutagenic agent, Trenimon, were examined. This was accomplished by measuring the frequency of dominant lethal mutations arising from mating of treated males with nontreated females. Adult male mice were treated with 5% (v/v) ethanol as part of a liquid diet (28% ethanol-derived calories) for five weeks; 10 mg/kg body weight (p.o.) THC every two days for five weeks; a single injection of Trenimon (0.125 mg/kg, i.p.) on day 28 of diet treatment; and all combinations of treatments. The control group was pair-fed a liquid diet in which isocaloric sucrose replaced ethanol; these males were also given sesame oil (vehicle for THC) and saline (vehicle for Trenimon) on the same schedule as that for the treated males. Neither body weights nor hematocrits were adversely affected by any treatment. Both ethanol and Trenimon treatments resulted in a small (8-9%; p less than 0.05) decrease in testicular weight. The effect of combined treatment with ethanol and Trenimon was roughly additive. Treatment with THC had no effect on testicular weight. Seminal vesicle weights were not affected by any treatment. Treatments were without significant effect on fertility, as measured by the frequency of males producing pregnancies. Ethanol and Trenimon treatments produced approximately 3- and 7-fold increases, respectively in the frequencies of preimplantational loss over that seen for the control group (7.3%), resulting in significant ethanol and Trenimon effects (p less than 0.001). No interactive effects of ethanol and Trenimon treatments were noted. Frequencies of dead fetuses per pregnancy in the ethanol- and Trenimon-treated groups were increased approximately 2.5- and 4-fold, respectively, over the control value of approximately 16%. However, the effect of combined treatments was not greater than that due to Trenimon alone, resulting in Trenimon and ethanol effects (p less than 0.001) and ethanol-Trenimon interaction (p less than 0.001). The calculated mutation index resulting from each treatment yielded significant (p less than 0.001) ethanol- and Trenimon-induced effects. In contrast to effects of ethanol and Trenimon treatments, THC, given alone, or in combination with ethanol and/or Trenimon, had no effect on either preimplantational loss, fetal mortality or the resulting mutation index. The data suggest that chronic ethanol treatment, at levels resulting in minimal fertility impairment, increases the frequency of dominant lethal mutations. In contrast, chronic treatment with THC, as administered in the present study, appears to be without effect.(ABSTRACT TRUNCATED AT 400 WORDS)

Analysis of Variance↗
PubMed1992

Gradient amplifier imperfections in NMR imaging.

This paper describes the influence of the transition distortion of gradient amplifiers on direct Fourier NMR imaging techniques. We demonstrate artifacts arising in the real measurement of the spin density images. Image artifacts are compared with artifacts obtained by computer simulations of the transition distortion of gradient amplifiers.

Artifacts↗
PubMed1992

Integration site-dependent transgene expression used to mark subpopulations of cells in vivo: an example from the neuromuscular junction.

To produce transgenic mice, an exogenous gene is inserted into the germ line, usually by injection of the DNA construct into a pronucleus of a fertilized egg. In most cases the transgene is integrated into the genome at a single random site. Frequently, the transgenes are combinations of regulatory elements from one gene and protein coding sequences from another gene, the reporter. As expected, the promoter in the construct usually controls the expression pattern of the reporter. In some cases, however, transgenes have been constructed with regulatory elements that are not able to direct transcription on their own. In animals containing such transgenes, the expression of the reporter is dependent on endogenous regulatory elements near the chromosomal site of transgene integration. In the present study, an Escherichia coli beta-galactosidase (lacZ) reporter gene linked to a weak promoter was selectively expressed in discrete subpopulations of cells in each of eight independently derived lines of mice. In one line (line 42), which we analyzed in detail, a subset of cells in skeletal muscle were lacZ-positive. Specifically, fibroblasts close to neuromuscular junctions expressed the lacZ-protein, whereas skeletal muscle fibroblasts far from synaptic sites and fibroblasts in other organs were lacZ-negative. Moreover, Schwann cells at nerve terminals were lacZ-positive, whereas Schwann cells in extramuscular nerves were lacZ-negative. These results indicate the existence of differences between perisynaptic and extrasynaptic fibroblasts in normal skeletal muscle. They also demonstrate how such transgenic mice can be used to identify and mark discrete cell populations.

Animals↗
PubMed1992

[Cancer rehabilitation in the Federal Republic of Germany--a critical review from the perspective of rehabilitation psychology].

Against the background of a common criticism of the rehabilitation system, the situation of rehabilitation research and practice in oncology is reviewed. A lack of efforts aimed at vocational rehabilitation as well as the main emphasis in inpatient services is criticized. Till now, outpatient services as well as psychosocial rehabilitation care are not as well established, as they should be with regard to provide assistance in coping with the disease and in adapting to the various disabilities may be followed by cancer. As rehabilitation research in oncology is still at its very beginning, we know little about the acceptance of rehabilitation measures as well as the rehabilitation process in its correlation between outcome criteria. Our own pilot study provides first results concerning vocational rehabilitation and acceptance of medical rehabilitation services. As conclusion, we need more elaborated research in oncological rehabilitation for optimizing and further developing rehabilitation care system especially with respect to outpatient and psychosocial services.

Ambulatory Care↗
PubMed1992

[Occupational stress and decreased performance of psychiatric patients].

After a short summary of the state of research on problems of work performance and job strains of psychiatric patients, a pilot study in job and task analysis is presented which examines job strains and impairment of work performance of psychiatric patients in various vocational rehabilitation facilities, based on the interactive theory of subjective job analysis. Together with semi-structured interviews and self-developed rating scales for measuring impairment of work performance, standardized questionnaires in job analysis (SAA, Martin et al. 1980; ABB, Neuberger & Allerbeck 1978) are used. On comparison of the patients in the various rehabilitation facilities, differences in work performance and appraisal of job strains and work conditions were found. By discriminant analysis two types of facilities could be differentiated especially by features like work performance and prehospital vocational integration. The results of multiple regression analysis show that the impairment of work performance is influenced in particular by previous vocational integration and by the patients' appraisal of future vocational perspective. The results are discussed in comparison with other research studies in psychiatric rehabilitation. Further studies are suggested, inter alia, to record the present psychiatric state in a systematic manner and to include long-term criteria for success in vocational rehabilitation.

Adult↗
PubMed1991

Effects on isolated arteries from rat, rabbit and man of NNC 70-0270, a synthetic atrial natriuretic factor analogue with a prolonged action.

A new analogue of ANF (atrial natriuretic factor), NNC 70-0270, was tested in various isolated artery preparations. In the rabbit aorta and renal artery NNC 70-0270 was compared with atriopeptin III and the relative inhibitory potency against noradrenaline-induced contractions (atriopeptin III = 1) was found to be 5 and 9, respectively. Furthermore the duration of the effect (after washout) was prolonged. In the rat aorta the relative potency was 0.5 and a prolonged effect was also found in this preparation. In the human pulmonary artery alpha-hANF was used as a reference, and contractions were induced with noradrenaline (seven experiments) or potassium chloride (three experiments). The relative (alpha-hANF = 1) inhibitory potencies were 0.8 and 1.3, respectively. A pronounced prolongation of the effect was also found in this preparation.

Animals↗
PubMed1991

A neuron-silicon junction: a Retzius cell of the leech on an insulated-gate field-effect transistor.

An identified neuron of the leech, a Retzius cell, has been attached to the open gate of a p-channel field-effect transistor. Action potentials, spontaneous or stimulated, modulate directly the source-drain current in silicon. The electronic signals match the shape of the action potential. The average voltage on the gate was up to 25 percent of the intracellular voltage change. Occasionally weak signals that resemble the first derivative of the action potential were observed. The junctions can be described by a model that includes capacitive coupling of the plasma membrane and the gate oxide and that accounts for variable resistance of the seal.

Action Potentials↗
PubMed1991

Integration site-dependent expression of a transgene reveals specialized features of cells associated with neuromuscular junctions.

After skeletal muscle is denervated, fibroblasts near neuromuscular junctions proliferate more than fibroblasts distant from synaptic sites, and they accumulate adhesive molecules such as tenascin (Gatchalian, C. L., M. Schachner, and J. R. Sanes. 1989. J. Cell Biol. 108:1873-1890). This response could reflect signals that arise perisynaptically after denervation, preexisting differences between perisynaptic and extrasynaptic fibroblasts, or both. Here, we describe a line of transgenic mice in which patterns of transgene expression provide direct evidence for differences between perisynaptic and extrasynaptic fibroblasts in normal muscle. Transgenic mice were generated using regulatory elements from a major histocompatibility complex (MHC) class I gene linked to the Escherichia coli beta-galactosidase (lacZ) gene. Expression of lacZ was detected histochemically. In each of eight lines, lacZ was detected in different subsets of cells, none of which included lymphocytes. In contrast, endogenous MHC is expressed in most tissues and at high levels in lymphocytes. Thus, the MHC gene sequences appeared inactive in the transgene, and lacZ expression was apparently controlled by genomic regulatory elements that were specific for the insertion site. In one line, cells close to the neuromuscular junction were lacZ positive in embryonic and young postnatal mice. Electron microscopy identified these cells as fibroblasts and Schwann cells associated with motor nerve terminals, as well as endoneurial fibroblasts, perineurial cells, and Schwann cells in the distal branches of motor nerves. No intramuscular cells greater than 200 microns from synaptic sites were lacZ positive. These results indicate that there are molecular differences between perisynaptic and extrasynaptic fibroblasts even in normal muscle and that diverse perisynaptic cell types share a specific pattern of gene expression.

Animals↗
PubMed1991

Different inhibitory potencies of various ANF-analogues in the isolated aorta from four rodent species.

Five ANF (atrial natriuretic factor) analogues were tested under similar conditions for their inhibitory potency against noradrenaline induced contractions in the isolated aorta from rabbits, rats, mice and guinea-pigs. The test compounds were: rat ANF 99-126, rat ANF 103-123, [Mpr105-Ala107] rat ANF 105-126-NH2 (PL-058), human ANF 105-126 and human ANF 99-126 oxidized at Met110. The potencies of the test peptides were compared to that of the reference peptide alpha-human ANF 99-126, the potency of which was set to 1. The EC50 values for the reference peptide varied between 2.4 (rabbit) and 6.6 (rat) x 10(-10) M. The highest and lowest relative potencies of the test peptides were: rat ANF 99-126: 2.6 (rat) and 1.4 (guinea-pig); rat ANF 103-123: 1.0 (rat) and 0.005 (rabbit); PL-058: 47 (mouse) and 5 (rabbit); human ANF 105-126: 2.1 (guinea-pig) and 0.5 (rabbit); oxidized human ANF 99-126: 0.3 (guinea-pig) and 0.02 (rat). The species related differences in the relative potencies of the peptides are probably due to structural dissimilarities of the vascular ANF receptors in the different species.

Animals↗
PubMed1990

Effects of transgenes for human and bovine growth hormones on age-related changes in ovarian morphology in mice.

The expression of human growth hormone (GH) in female transgenic mice (TM) is accompanied by sterility, whereas females expressing the bovine GH gene are fertile. A light and electron microscopic study was conducted to examine whether expression of these foreign GH genes in mice is associated with structural changes in the ovaries of young adult (3-month-old) or middle-aged (7-month-old) mice. One ovary was serially sectioned for light microscopy, and the contralateral ovary was used for electron microscopy. The numbers of preantral (PAF) and antral (AF) follicles, with and without signs of atresia, as well as the number of corpora lutea (CL), were determined. As expected, body weights of both young and middle-aged TM of either kind were significantly increased over those of their normal littermates. However, the ovarian weights of TM and control mice did not differ. In the 3-month-old TM, the ovaries were grossly normal at the light microscopic level. However, significantly more CL were counted in the ovaries of human GH-TM than in those of the other two groups. The percentage of PAF with signs of atresia was significantly reduced in ovaries of bovine GH-TM compared with the other groups, while the percentages of AF undergoing atresia were significantly different in all groups, with the highest values in normal animals, intermediate ones in human GH-TM, and the lowest in bovine GH-TM. In the ovaries of 7-month-old human GH-TM, conspicuous clusters of large, foamy light cells were present in the cortex and the medulla. Ultrastructurally, these cells appeared as interstitial cells in various stages of degeneration, accumulating cholesterol crystal-like inclusions. Although degeneration of interstitial cells was observed also in the other types of animals, it involved usually only single cells and no cytoplasmic crystal inclusions. Moreover, in the ovaries of 7-month-old human GH-TM the percentages of PAF were significantly reduced and the percentages of AF significantly increased compared with those in the two other groups, which did not differ from each other with respect to these parameters. No significant differences in the numbers of CL were found between the groups. Percentages of atretic PAF were significantly reduced in bovine GH-TM and comparable in the other two groups, while percentages of atretic AF were not different between normal and bovine GH-TM, but were significantly increased in human GH-TM.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1990

Unusually long survival time after resection and irradiation of a brain metastasis from osteosarcoma.

Cerebral metastases of osteosarcomas are rare. The cases published up to now have manifested only a short relapse-free period of survival. Intracranial filia generation must be anticipated if metastasis formation takes place in the lung. We report here on a young patient who underwent operation for an intraparenchymal cerebral metastasis 76 months after amputation of the left leg due to an osteosarcoma chondroblasticum, and who is, at present, healthy, 13 months after resection. This unusually long survival time is attributed to the good neurological status before craniotomy, early diagnosis, and the improvement of the cytostatic therapy (COSS-80-scheme).

Antineoplastic Combined Chemotherapy Protocols↗