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Biomedical subjects

J Bauer

Publications and source records attributed to J Bauer.

At least 469 records · Page 26Linked to original sources
PubMed1990

Amplification of N-myc oncogene in human melanoma cells.

Tissue specimens from two melanoma patients and two patients with laryngeal carcinoma were studied for the expression of c-myc, N-myc and v-src oncogenes. Out of three different probes, only the N-myc probe one signalled amplification. While the two patients with laryngeal carcinoma showed only single copy of the N-myc gene in tumor cells, amplification of this gene was found in both two melanoma patients. The patients with 1 extra copy of the N-myc gene and its protein product had an early recurrence but is still alive, while the other melanoma patient with 4 extra copies of the gene, relapsed very early and died of melanoma within 7 months after diagnosis. Thus a higher amplification (4 extra copies) seems to correlate with very poor outcome of the disease.

Adult↗
PubMed1989

Characterization of mononuclear-phagocyte terminal maturation by mRNA phenotyping using a set of cloned cDNA probes.

The terminal step in the maturation of mononuclear cells from circulating monocytes to resident macrophages is accompanied by dramatic changes in cell morphology and physiology. Applying a cultivation system which allows peripheral monocytes to undergo terminal maturation in vitro under absolutely endotoxin-free conditions, we have determined the pattern of expression of a set of eight genes by mRNA phenotyping. The results can be summarized as follows: the two protease inhibitors alpha 1-antitrypsin and alpha 2-macroglobulin show a inverse pattern of expression. alpha 1-Antitrypsin mRNA is repressed, alpha 2-macroglobulin mRNA is strongly induced during maturation to macrophages. Therefore, these two genes are excellent markers of the terminal maturation. In addition, ferritin-light-chain mRNA progressively increases during the course of differentiation, providing a further marker for maturation. Gene expression as a function of activation was studied in mononuclear cells stimulated with bacterial endotoxin (lipopolysaccharide). In monocytes, complement-factor-B, interleukin-1 and interleukin-6 mRNAs are drastically induced upon lipopolysaccharide activation whereas lysozyme RNA is strongly repressed. However, the ability of all four genes to respond to endotoxin was markedly diminished or abolished in mature macrophages, indicating that susceptibility to a certain type of activation may be restricted to a specific stage of maturation. Our data show that mRNA phenotyping is excellently suited for the characterization of the differentiation and activation state of mononuclear phagocytes.

Blotting, Northern↗
PubMed1989

Regulation of interleukin 6 receptor expression in human monocytes and monocyte-derived macrophages. Comparison with the expression in human hepatocytes.

IL-6 is a cytokine with pleiotropic biological functions, including induction of the hepatic acute phase response and differentiation of activated B cells into Ig-secreting plasma cells. We found that human peripheral blood monocytes express the IL-6-R, which is undetectable on the large majority of lymphocytes of healthy individuals. Stimulation of monocytes by endotoxin or IL-1 causes a rapid downregulation of IL-6-R mRNA levels and a concomitant enhancement of IL-6 mRNA expression. IL-6 itself was found to suppress the IL-6-R at high concentrations. A gradual decrease of IL-6-R mRNA levels was observed along in vitro maturation of monocytes into macrophages. We show that downregulation of IL-6-R mRNA levels by IL-1 and IL-6 is monocyte specific, since IL-6-R expression is stimulated by both IL-1 and IL-6 in cultured human primary hepatocytes. Our data indicate that under noninflammatory conditions, monocytes may play a role in binding of trace amounts of circulating IL-6. Repression of monocytic IL-6-R and stimulation of hepatocytic IL-6-R synthesis may represent a shift of the IL-6 tissue targets under inflammatory conditions.

Blotting, Northern↗
PubMed1989

Interleukin-6 and its receptor during homeostasis, inflammation, and tumor growth.

This review focuses on describing the specific role of interleukin-6 within the network of inflammatory mediators in man. Sites of interleukin-6 synthesis, regulation of its expression, and the biological functions of this molecule are here outlined. The potential role of interleukin-6 as a diagnostic monitor is discussed. Particular attention is paid to experimental evidence that interleukin-6 and its receptor may be involved in the pathogenesis of autocrine tumor growth. A recently proposed therapeutical use of cytotoxic interleukin-6 fusion proteins in order to selectively, destroy certain interleukin-6 receptor bearing tumor cells is discussed in the light of the finding, that not only hepatocytes, but also normal peripheral blood monocytes express the interleukin-6 receptor.

Acute-Phase Reaction↗
PubMed1989

Regulation of interleukin-6 receptor expression in human monocytes and hepatocytes.

Human blood monocytes normally express the interleukin-6 receptor. Treatment of cultured monocytes with endotoxin, interleukin-1 beta, or interleukin-6 results in a decrease in interleukin-6 receptor mRNA levels. Glucocorticoids aso cause a drop in monocytic interleukin-6 receptor mRNA levels. We also found interleukin-6 receptor expression in cultured human hepatocytes, but in contrast to monocytes, where interleukin-6 receptor mRNA is presented by the ligand and by interleukin-1, treatment of hepatocytes with interleukin-6 or interleukin-1 resulted in increased interleukin-6 receptor mRNA levels. Induction of interleukin-6 receptor mRNA in hepatocytes was less pronounced when glucocorticoids were omitted from the culture medium. We conclude that during noninflammatory homeostasis, blood monocytes are involved in binding of trace amounts of circulating interleukin-6. During inflammatory events, the main target of interleukin-6 may be changed from the monocytic population not only to activated B-cells, but also to the hepatocytes.

Acute-Phase Reaction↗
PubMed1989

[The diagnosis of functional epigastric syndrome].

The radiological examination of the stomach and the duodenum under functional aspects resulted in references of an irritative stomach in patients with epigastric complaints without conceivable organic findings lasting for many years. On the basis of simultaneously established peculiarities in the behaviour and the social situation of the patients concerned the disturbance of kinetics demonstrated is realized with great probability and explained as pathological by the patient. The results of the examination may be points of influence for the therapy of such disturbances.

Adult↗
PubMed1989

Tumor necrosis factor-alpha induces a kappa B sequence-specific DNA-binding protein in human hepatoblastoma HepG2 cells.

Tumor necrosis factor-alpha is an inducer of acute-phase protein synthesis in liver cells. The mechanism by which tumor necrosis factor-alpha alters gene expression in these cells is largely unknown. In this study, we demonstrate that tumor necrosis factor-alpha stimulates human immunodeficiency virus-1 long terminal repeat-promoted gene expression in the human hepatoblastoma HepG2 cell line and increased binding of trans-activating factors to kappa B (kappa B) DNA sequences. In contrast to lymphocytic cells where the nuclear factors recognizing the kappa B sequences are activated by both tumor necrosis factor-alpha and phorbol-12-myristate-13-acetate through a posttranslational mechanism, in HepG2 cells phorbol-12-myristate-13-acetate does not activate these factor(s), and de novo protein synthesis seems to be required in HepG2 cells for gene activation by tumor necrosis factor-alpha.

Base Sequence↗
PubMed1989

CT, MRI and SPECT neuroimaging in status epilepticus with simple partial and complex partial seizures: case report.

A 35-year-old female patient suffering from epilepsy was examined during status epilepticus with simple partial and complex partial seizures by means of EEG, CT, MRI and ictal SPECT. All these examinations showed focal abnormalities with identical location due to oedema and hypervascularisation; these were, however, absent during examinations carried out before and after status epilepticus.

Adult↗
PubMed1989

Stimulation by a bacterial extract (Broncho-Vaxom) of the metabolic and functional activities of murine macrophages.

Peritoneal and bone marrow-derived macrophages of the C57BL/6 and DBA/2 mouse strains were exposed in vitro to increasing concentrations of the bacterial lysate Broncho-Vaxom (BV), in the presence or absence of macrophage-activating factor (MAF)-rich media. Two metabolic pathways and two functional activities of the macrophages were studied. First, oxidative metabolism was found to increase sharply in macrophages incubated with BV, as measured by the catabolism of glucose via the hexose monophosphate shunt pathway, and by the production of the superoxide anion (O2-). Both effects were further increased by co-stimulation of macrophages with MAF. Second, exposure to BV together with MAF (or with recombinant murine interferon-gamma) led to acquisition by macrophages of the capacity to destroy the intracellular parasite Leishmania enriettii; such activated macrophages were also lytic towards P815 mastocytoma indicator target cells. These cytotoxic properties failed to develop in the absence of MAF. The BV-dependent increase in metabolic and functional activities was of the same magnitude as that induced by incubation of macrophages with 10 ng/ml of bacterial lipopolysaccharide (LPS). Residual contamination of BV by endotoxin was however much lower. In addition, polymyxin B, a LPS inhibitor, blocked the effect of LPS without significantly affecting macrophage stimulation by BV. These experiments indicate that BV can markedly stimulate macrophage metabolic and functional parameters that are important for host defense against pathogens and tumors.

Adjuvants, Immunologic↗
PubMed1989

Free flow electrophoresis in space shuttle program (Biotex).

In the space shuttle program free flow electrophoresis will be applied for separation of proteins, biopolymers and cells. Proteins are to be separated according to the "Feldsprung-Gradienten" procedure by Prof. H. Wagner, University of Saarbruecken, biopolymers are to be separated by the isotachophoresis technique by Prof. Schmitz, University of Muenster and we intend to separate cells in order to increase the efficiency of recovery of hybrid cells after electrofusion performed under microgravity in collaboration with Prof. U. Zimmermann, University of Wuerzburg. There are supposed two ways for reaching this goal: 1) Enrichment of cells before electrofusion may enhance the probability that the cells of interest are immortalized. 2) Separation of cells after electrofusion may help to clone the hybrid cells of interest. Under microgravity, the combination of improved electrophoresis with higher electrofusion rates may provide new possibilities for immortalization of cells. This may be a new way to obtain cellular products, which are physiologically glycosylated.

Animals↗
PubMed1989

From visual acuity to hyperacuity: a 10-year update.

Visual acuity, the most basic measure of developing pattern vision in human infants, has been used extensively for detecting anomalies of vision and oculomotor coordination. In the past 10 years much has been learned about the development of two hyperacuities, namely, vernier acuity and stereoacuity. These two acuities become superior to grating acuity after the third month and remain so throughout life. Compared to females, males show slower development of stereopsis and vernier acuity, but not grating acuity, during the third through sixth months. We have suggested that this may result from the neurotrophic effects of the early pulse of testosterone found in males. Measures of vernier acuity have proven effective in detecting meridional amblyopia in older children who had significant astigmatism in the first year and subsequently lost it. The susceptible period for acquiring meridional amblyopia extends from the second half of the first year to at least the end of the second year. Deviations from the typical oblique effect (equal acuity for vertical and horizontal edges; equal, but lower, acuity for left oblique and right oblique) may result from uncorrected astigmatism early in life.

Amblyopia↗
PubMed1989

[Neurophysiologic principles and clinical value of post-convulsive serum prolactin determination in epileptic seizure].

Measurement of postictal serum-prolactin concentrations in epileptic seizures in order to distinguish them from psychogenic seizures is at present used only rarely and non-systematically. Studies of 209 Grand mal seizures, 232 complex-partial seizures, 102 simple-partial seizures and 15 generalized seizures published between 1980 and 1987 differ in their standards of seizure classification as well as in their criteria for evaluating increases in postictal serum-prolactin concentrations. A significant rise was seen in 88% of Grand mal seizures, 78% of complex-partial seizures, 22% of simple-partial seizures and 6% of generalized seizures. The discussion of both these general findings and our own investigations is based on the presentation of neuroanatomical and neurophysiological principles of prolactin secretion.

Adult↗
PubMed1989

Isolation of a mycotoxin (gliotoxin) from a bovine udder infected with Aspergillus fumigatus.

A bovine udder infected with Aspergillus fumigatus was analysed by physico-chemical methods (thin layer chromatography, high performance liquid chromatography and direct exposure probe-mass spectrometry) for the presence of mycotoxins. Gliotoxin, a fungal metabolite with cytotoxic and immunosuppressive properties was isolated for the first time from naturally infected tissue. The gliotoxin concentration analysed (9.2 mg kg-1 udder) was approximately 100 times higher than the concentration known to produce morphological changes of cells. Gliotoxin may play an important role in the establishment and development of an infection with A fumigatus.

Animals↗
PubMed1989

Epileptic but not psychogenic seizures are accompanied by simultaneous elevation of serum pituitary hormones and cortisol levels.

The circadian rhythm of serum prolactin was determined in 12 patients with seizures, and 28 age- and sex-matched healthy subjects (14 men and 14 women). Blood was also collected every 15 min for 2 h immediately after a simultaneously video/EEG-documented epileptic (6 patients) and psychogenic seizure (5 patients) for the determination of prolactin, thyrotropin, growth hormone, cortisol, melatonin, catecholamines and serotonin. During the seizure-free interval, the circadian profile of serum prolactin was lower in female patients than in healthy women. Serum prolactin, thyrotropin, growth hormone, and cortisol were increased postictally, followed by a decrease, after a grand mal or complex partial seizure, but not after a psychogenic seizure in comparison to baseline serum hormone levels obtained during the same time on a seizure-free day. During the seizure and for 2 h afterwards, blood serotonin, serum melatonin, dopamine, and epinephrine did not alter and were within the reference limits of healthy subjects. Serum norepinephrine was lower in patients compared to healthy subjects (p less than 0.05). The simultaneous elevation of serum prolactin, thyrotropin, growth hormone, and cortisol points to a central stimulation of the hypothalamic-pituitary axis during an epileptic seizure, but not during seizures of psychogenic origin.

Catecholamines↗
PubMed1989

Thermotoxicity of palacos cement. Clinical observation.

In total hip joint replacement with cemented prostheses, Palacos (polymethyl methacrylate, PMMA) involves a high perioperative risk for the patient, on account of the effects on both the systemic and the pulmonary circulation. Data were assembled retrospectively from the records of 203 patients who underwent hip joint operation with Palacos implantation in the Inner City Surgical Clinic and the Surgical Polyclinic of the University of Munich from 1982 to 1986. In the hemiarthroplasty series, hemiarthroplasty was performed in 61% of patients in risk group III, whereas in the risk groups I and II it was done in 31% of cases. The mortality following hemiarthroplasty was greater than that following implantation of total prostheses in risk groups I and II. In risk groups II and III the mortality was 17% with surgery on the day of injury, lower, at only 10%, when the operation was performed on the day after injury, and markedly higher, at 31% and 38%, respectively, when surgery was postponed to the 2nd or 3rd day. It has been shown in burn research that the prostanoid levels in the plasma of untreated animals show a typical curve with two peaks, the first on the day of the injury and the second on the 3rd day after injury. Our observations support the assumption that the effect of trauma and surgical treatment are complementary.

Aged↗
PubMed1989

Lipopolysaccharide-free conditions in primary astrocyte cultures allow growth and isolation of microglial cells.

Primary rat astrocyte cultures were used to isolate a macrophage population that does not adhere to the confluent glial cells. The cells multiplied vigorously in coculture with astrocytes during the 14 d culture period, provided that functionally active lipopolysaccharide (LPS) was either absent or present in very low concentrations. Based on morphological, immunocytochemical, and pharmacological data, it was concluded that the isolated cells were microglia, the resident macrophages of the brain. The findings characterized them as a distinct cell population that shares features both of peritoneal macrophages and of astroglial cells. Like peritoneal macrophages, the isolated cells were able to phagocytize as shown by their ingestion of latex beads and uptake of L-leucyl methylester. Furthermore, they were immunocytochemically stainable by a specific monoclonal antibody (ED 1) against a macrophage-specific antigen (Dijkstra et al., 1985). They also synthesized prostaglandin E2 (PGE2) and secreted interleukin 1 (IL-1) upon stimulation with LPS. Upon stimulation with the ionophore A23187, PGD2, the predominant prostaglandin of the brain, was the major PG metabolite released by these cells. In contrast to peritoneal macrophages, microglial cells were able to multiply. Proliferation of microglial cells in coculture with astrocytes was suppressed when 2 ng LPS/ml or higher concentrations were added to astroglial culture media. These astrocyte cultures, which contained approximately 1% microglia, were used to investigate the influence of LPS on prostaglandin and IL-1 secretion in order to compare astroglial and microglial features. Increasing LPS concentrations induced increased PGE2 secretion, whereas PGD2 secretion was essentially unaffected by LPS. The critical influence of LPS contaminations in most of the commercially available animal sera used for astrocyte cultures on cellular composition in general and on metabolism of hormones and growth factors in particular is discussed.

Animals↗
PubMed1989

Mesenteric fibromatosis in Gardner's syndrome.

Gardner's syndrome, first described in the 1950s, is a composite clinical entity characterized by intestinal polyps, osteomas, fibromas, and epidermal cysts. A case of mesenteric fibromatosis in Gardner's syndrome is presented. Whereas most of the literature on this subject stresses the significance of the intestinal polyposis and its premalignant potential, in this paper the serious significance of the intraabdominal fibromas is stressed. This case demonstrates an unusual complication of erosion of this tumor into the small intestine, resulting in multiple intestinal fistulae with abscess formation. Surgical management of this problem necessitated resection of the fibroma and involved small intestine. A review of the literature is presented.

Adult↗