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Biomedical subjects

G Wolf

Publications and source records attributed to G Wolf.

At least 199 records · Page 11Linked to original sources
PubMed1998

Differentially expressed genes in hippocampal cell cultures in response to an excitotoxic insult by quinolinic acid.

The NMDA-type glutamate receptor agonist quinolinic acid (QA), which causes tissue lesions in the rat brain as well as cell loss in neuronal cultures, is widely used in models of glutamate excitotoxicity. The aim of this study was to evaluate the alterations in gene expression in a primary hippocampal cell culture after exposure to QA. By means of differential mRNA display, we were able to pinpoint as many as 23 bands which appeared to be upregulated after a 6-h treatment with quinolinic acid. The differential expression of 13 cDNAs could be confirmed by dot blot and/or Northern analysis. Of the cDNAs, the p112 regulatory subunit of the 26S proteasome, a PDGF-associated protein and the glia-derived protease nexin PN-1 could be identified. The results provide emphasis to the participation of proteolysis and protease inhibition in neurodegenerative processes.

Amino Acid Sequence↗
PubMed1998

Distinct regions of allelic imbalance on chromosome 10q22-q26 in squamous cell carcinomas of the lung.

The genetic mechanisms underlying the progression to the metastatic phenotype of lung cancer are poorly understood. We recently showed that small cell lung cancer (SCLC) and metastasizing squamous cell carcinomas are characterized by an increased incidence of allelic loss on chromosome 10q. In the present study we performed a deletion mapping using 24 polymorphic markers on chromosome 10q22-q26 in 39 squamous cell carcinomas (SCC) of the lung identifying 14 metastatic carcinomas (74%) and three non-metastatic SCC (15%) with allelic imbalance. The allelotype analysis indicated three regions of allelic loss that were clustered at the loci Afm086/D10S541, D10S185 and D10S1782/D10S169. A localized microsatellite instability was observed in two carcinomas for the markers D10S1686 and D10S1782. In addition the PTEN/MMAC1 gene was analysed by direct DNA sequencing and Southern blot analysis in 25 and 28 carcinomas, respectively, without detecting any genomic alterations. Similarly, no altered transcript was detected in 15 tumor cell lines and 20 primary tumors by Northern blot analysis or RT-PCR. In summary, three distinct regions of allelic imbalance were identified suggesting that multiple tumor suppressor genes on chromosome 10q contribute to tumor progression and metastases formation of lung cancer.

Alleles↗
PubMed1998

Distribution of the endothelial constitutive nitric oxide synthase in the developing rat brain: an immunohistochemical study.

The present study deals with the distribution of endothelial constitutive nitric oxide synthase (ecNOS) in the developing rat brain using optimized protocols for preparation and fixation and the tyramide-signal-amplification technique. The immunostaining patterns of a monoclonal antibody against ecNOS are compared with results obtained with a rat pan-endothelial marker, the monoclonal RECA-1 antibody. It is shown that ecNOS is present in the endothelial lining of all types of blood vessels and the choroid plexuses of the rat brain from the beginning of vasculogenesis at embryonic day 11 until adulthood (75 weeks). The same is true for RECA-1 immunoreactivity, that was demonstrated in the developmental brain vasculature for the first time. Both antigens expressed identical immunostaining patterns. At all investigated stages of brain development neither ecNOS negative blood vessels nor ecNOS positive non-endothelial cells, e.g., neurons, were found. The data indicate that ecNOS is involved in the embryonic angiogenesis and the regulation of hemodynamic functions of brain vasculature throughout the individual life.

Animals↗
PubMed1998

Genomic alterations associated with malignancy in head and neck cancer.

BACKGROUND: Comparative genomic hybridization (CGH) was performed on 50 primary head and neck squamous cell carcinomas (HNSCC) to discover molecular genetic alterations underlying the progression of these tumors. METHODS: In CGH, equal amounts of differently labeled tumor deoxyribonucleic acid (DNA) and normal reference DNA were hybridized simultaneously to normal metaphase chromosomes. They were visualized by different fluorochromes, and the signal intensities were quantitated separately as gray levels along the single chromosomes. The over- and underrepresented DNA segments were determined by computation of ratio images and average ratio profiles. RESULTS: Prevalent changes observed in more than 50% of the HNSCC included deletions of chromosomes 1p, 4, 5q, 6q, 8p, 9p, 11, 13q, 18q, and 21q and DNA overrepresentations of 11q13 as well as 3q, 8q, 16p, 17q, 19, 20q, and 22q. The calculation of ratio profiles of tumor subgroups revealed that well differentiated carcinomas (G1) were defined by the deletions of chromosomes 3p, 5q, and 9p together with the overrepresentation of 3q, suggesting the association with early tumor development. Accordingly, the undifferentiated tumors (G3) were characterized by additional deletions of chromosomes 4q, 8p, 11q, 13q, 18q, 21q, and overrepresentations of 1p, 11q13, 19, and 22q. CONCLUSION: Our data indicate that the CGH patterns of chromosomal imbalances may help to define the malignant potential of head and neck squamous cell carcinomas.

Carcinoma, Squamous Cell↗
PubMed1998

Differential expression of superoxide dismutase isoforms in neuronal and glial compartments in the course of excitotoxically mediated neurodegeneration: relation to oxidative and nitrergic stress.

To examine the cellular distribution of radical scavenging enzymes in glia, in comparison to that in neurons and their behaviour during excitotoxically induced neurodegenerative processes, protein levels and the cellular localization of cytosolic and mitochondrial superoxide dismutase (Cu/Zn- and Mn-SOD) were investigated in the rat brain undergoing quinolinic acid (Quin)-induced neurodegeneration. Evidence for the specificity of the applied antibodies to detect immunocytochemically these SOD isoforms was obtained from electron microscopy and Western blotting. In control striatum Mn-SOD was clearly confined to neurons, whereas Cu/Zn-SOD was found, rather delicately, only in astrocytes. Microglia failed to stain with antibodies to both SOD isoforms. Quin application resulted in an initial formation of oxygen and nitrogen radicals as determined by the decline in the ratio of ascorbic to dehydroascorbic acid and by increased levels of nitrated proteins, an indicator for elevated peroxynitrite formation. Morphologically, massive neuronal damage was seen in parallel. Astroglia remained intact but showed initially decreased glutamine synthetase activities. The levels of Mn-SOD protein increased 2-fold 24 h after Quin injection (Western blotting) and declined only slowly over the time period considered (10 days). Cu/Zn-SOD levels increased only 1.3-fold. Immunocytochemical studies revealed that the increase in Mn-SOD is confined to neurons, whereas that of Cu/Zn-SOD was observed only in astroglial cells. Quiescent microglial cells were, as a rule, free of immunocytochemically detectable SOD, whereas in activated microglia a few Mn-SOD immunolabeled mitochondria occurred. Our results suggest a differential protective response in the Quin lesioned striatum in that Mn-SOD is upregulated in neurons and Cu/Zn-SOD in astroglia. Both SOD-isoforms are assumed to be induced to prevent oxidative and nitric oxide/peroxynitrite-mediated damage. In the border zone of the lesion core this strategy may contribute to resist the noxious stimulus.

Animals↗
PubMed1998

Evidence for CCK(B) receptors in the guinea-pig kidney: localization and characterization by [125I]gastrin binding studies and by RT-PCR.

Two types of receptors for gastrin and cholecystokinin (CCK) have been identified in the gastrointestinal tract and in the central nervous system: CCK(A) and CCK(B) receptors. Here we report evidence for the expression of CCK(B) receptors in the guinea-pig kidney. Specific binding sites for [125I]gastrin were detected in sections of the guinea-pig kidney: Binding was saturable, pH-, temperature- and time-dependent, and specific for gastrin-related peptides. The potencies for inhibition of binding of [125I]gastrin were CCK-8 > gastrin 17-I > CCK(B) receptor antagonist L-365,260 > des(SO3)CCK-8 > CCK(A) receptor antagonist L-364,718. Autoradiography demonstrated specific [125I]gastrin binding to medullary collecting ducts and to a much lesser extent to glomeruli, but not over other structures. CCK(B) receptor cDNA fragments were amplified by RT-PCR from total kidney, isolated tubuli and from tissues known to express CCK(B) receptors such as stomach and brain. The kidney might therefore be a previously unidentified site of action for gastrin and cholecystokinin-related peptides.

Aldosterone↗
PubMed1998

[Effect of topical corticosteroids and topical antihistaminics on ciliary epithelium of human nasal mucosa in vitro].

A normal ciliary beat frequency of ciliated cells is necessary for the mucociliary clearance of the nose and paranasal sinuses. An in vitro investigation was performed to evaluate the influence of topical corticosteroids and antihistamines on the ciliary beat frequency of human nasal mucosa. The nasal sprays examined contained the corticosteroids budesonide or fluticasone propionate and the topical antihistamines azelastine or levocabastine. All tests were performed on cell cultures of human nasal mucosa during constant conditions. Three of the four nasal sprays tested contained benzalkonium chloride as preservative. An irreversible cessation of ciliary movement was observed in all cells exposed to nasal sprays containing benzalkonium chloride in a 50 per cent solution. The nasal spray containing budesonide was benzalkonium chloride-free and caused minor but fully reversible decreases in ciliary beat frequency after 20 min. As benzalkonium chloride can cause complete standstill of ciliary beat frequency in vitro in human nasal mucosa, we recommend that this preservative should not be used anymore in topical nasal medications.

Administration, Topical↗
PubMed1998

Laceration of a benign adrenal adenoma mimicking a splenic rupture.

Lacerations of adrenal tumors are very rare events and have been described for myelolipoma, pheochromocytoma, and cortisol-producing adenoma. We report on a patient who was admitted with suspected splenic rupture. Computed tomography showed a mass 14 cm in diameter adjacent to the spleen, but selective angiography revealed blood supply by the left suprarenal artery. A ruptured adrenal tumor was therefore diagnosed and resected. No hormone production was detected. Histologically a benign adrenal adenoma was found. Frequency, diagnosis and therapy of adrenal masses are discussed.

Adenoma↗
PubMed1998

Three births after preimplantation genetic diagnosis for cystic fibrosis with sequential first and second polar body analysis.

OBJECTIVE: The purpose of this study was to determine the accuracy and feasibility of sequential polar body removal and analysis for preimplantation genetic diagnosis of mendelian disorders. STUDY DESIGN: Three couples with risk factors for cystic fibrosis had preimplantation genetic diagnosis with the use of sequential polar body analysis. After stimulation, oocytes were harvested and the first polar bodies were removed and analyzed on the day of aspiration. The following day, after fertilization, the second polar bodies were aspirated. Only embryos known to have inherited the normal maternal allele were transferred. RESULTS: All three couples had successful pregnancies resulting in the births of unaffected infants. CONCLUSIONS: Preimplantation diagnosis with the use of sequential polar body removal is feasible and can prevent the establishment of genetically abnormal pregnancies for couples at risk.

Alleles↗
PubMed1998

Unbalanced chromosomal aberrations in neuroendocrine lung tumors as detected by comparative genomic hybridization.

Typical and atypical carcinoids (TC, ATC) and small (SCLC) and large cell neuroendocrine carcinomas (LCNEC) constitute the spectrum of neuroendocrine lung tumors. Chromosomal aberrations have not been studied in LCNEC and only rarely in carcinoids. Only SCLCs have been investigated frequently for chromosomal aberrations. We compared three typical and four atypical carcinoids, one atypical carcinoid/SCLC mixed type, three SCLC, and three LCNEC for chromosomal gains and losses using comparative genomic hybridization. Typical carcinoids showed either no changes or only few chromosomal gains. Atypical carcinoids appeared genetically heterogeneous: One case had no aberrations, and three cases had few aberrations; two of them showed a deletion of 11q. SCLC and LCNEC were characterized by many gains and losses, especially similar changes of 3p, 5q, 5p, and 13q. Although ATC resemble LCNEC morphologically, there were no similarities at the genetic level. We have found a reciprocal relationship of prognosis and the amount of aberrations. TCs and ATCs with few chromosomal changes have the best prognosis, whereas SCLCs and LCNECs were generally characterized by a great amount of aberrations and worst prognosis. There was no unbalanced aberration common in all types of neuroendocrine tumors of the lung.

Carcinoid Tumor↗
PubMed1998

Absence of nitric oxide synthase in rat oligodendrocytes: a light and electron microscopic study.

The existence of nitric oxide synthase (NOS) in oligodendroglial cells is still a matter of debate. Therefore, by using immunocytochemistry, NADPH-diaphorase (NADPH-d) histochemistry and in-situ hybridization, NOS was analysed in oligodendroglial cells of rat brain tissue and in tissue cultures. Independent of the method utilized, NOS was found to be absent in oligodendrocytes. An exception was the presence of NADPH-d activity in some oligodendroglial cells when the electron microscopic BSPT-technique was used. However, this activity is probably not related to NOS. The absence of NO-producing capacity in these cells may explain their high vulnerability to radical-mediated toxicity.

Animals↗
PubMed1998

Effects of prenatal morphine exposure on NK cytotoxicity and responsiveness to LPS in rats.

Prenatal exposure to opiates can adversely affect fetal development, resulting in long-term growth retardation and impairments in physiological and behavioral functions. In the present study we studied long-term effects of prenatal morphine exposure on immune functions, including the activity of natural killer (NK) cells and the febrile and behavioral responses to lipopolysaccharide (LPS). Pregnant Fischer 344 rats were given increasing doses of morphine in slow release emulsion during gestational days 12-18. Control rats were injected with vehicle and were either pair fed to morphine rats or fed ad lib. Postnatal experiments were conducted when offspring were 10-12 weeks old. Compared to both control groups, rats prenatally exposed to morphine exhibited: 1) suppressed cytotoxic activity of NK cells; 2) reduced LPS-induced fever measured by a biotelemetric system; 3) reduced hyperalgesia measured by the hot-plate test at 30 min, and augmented hypoalgesia at 2-6 h post-LPS; 4) higher open-field activity in saline-treated animals, and more pronounced suppression of activity in LPS-injected animals; 5) LPS-induced reduction of food consumption, body weight, and social exploration, which did not differ from the reduction observed in control animals. These findings indicate that prenatal exposure to morphine induces long-term impairment of host-defense mechanisms, which may render the offspring more susceptible to infectious diseases.

Analgesia↗
PubMed1998

Subcellular localization of the neuronal isoform of nitric oxide synthase in the rat brain: a critical evaluation.

In the aldehyde-fixed rat brain NADPH-diaphorase is suggested to be related to brain nitric oxide synthase but also to other isoforms of this enzyme as well as to several non-related types of NADPH-oxidoreductases. In this study NADPH-diaphorase histochemistry using the tetrazolium salt BSPT (2-(2'-benzothiazolyl)-5-styryl-3-(4'-phthalhydrazidyl)-tetrazoliu m chloride) (to yield an electron dense formazan) and immunocytochemistry were applied for the cellular and subcellular localization of brain nitric oxide synthase in the striatum and the pontine laterodorsal tegmental nucleus of the rat. Combining the two techniques, in both brain regions identical distribution patterns of heavily-stained neurons were observed at the light microscopic level. There are inconsistencies in the literature with regard to the subcellular localization of brain nitric oxide synthase and NADPH-diaphorase in neurons. In our results brain nitric oxide synthase immunoreactivity in abundantly stained neurons was mainly cytosolically distributed, sometimes in a patch-like form and distant from membranes, whereas the NADPH-diaphorase reaction product BSPT-formazan was closely attached to discrete portions of intracellular membranes. Other neurons and glial cells including their processes showed also, but to a lesser extent, formazan-labelled membrane portions. In such cell populations brain nitric oxide synthase immunoreactivity was not detectable. Possible reasons for these inconsistencies are discussed in detail. The strength but not the specificity of the NADPH-diaphorase related reaction was shown to be dependent on concentrations of Triton X-100 and tetrazolium salt. We suggest that, for electron microscopical cytochemistry, the BSPT technique combined with other independent techniques, such as immunocytochemistry and in situ hybridization, may be a viable means for the identification and subcellular localization of the different nitric oxide synthase isoforms, and to discriminate them from other types of NADPH-diaphorases.

Animals↗
PubMed1998

Cytogenetic investigations in employees from waste disposal sites.

In connection with extensive health studies of employees from two big central waste disposal sites, cytogenetic investigations were performed. The subject of these special analyses was to examine whether the complex mixture of pollutants from waste disposal sites comprises a genotoxic hazardous potential. Cytogenetic analyses were performed on peripheral blood lymphocytes of 82 exposed and 71 control persons as a coded study. For chromosome analysis, 1000 cells and for sister chromatid exchange (SCE) analysis, 50 cells had been scored per person. Compared with the matched control group, a highly significant increase of the frequencies of chromosomal aberrations was detected, especially in dicentric chromosomes (4.1 +/- 0.2 vs 1.5 +/- 0.1 per 1000 cells) and acentric fragments (6.9 +/- 0.3 vs 2.8 +/- 0.2 per 1000 cells), whereas no difference was found in SCE analysis. The occurrence of multiaberrant cells with more than two dicentric chromosomes was a striking feature in waste disposal site workers (23 vs 1 in control group). Frequencies of chromosomal aberrations were similar in exposed non-smokers and smokers. Only in the control group, a significant difference was observed in the incidence of dicentric chromosomes and SCE between non-smokers and smokers. The results of the first cytogenetic investigations on employees of two waste disposal sites indicate a genotoxic hazardous potential. Further research is urgently required.

Adult↗
PubMed1998

Neuronal nitric oxide synthase in the vasculature of the rat brain: an immunocytochemical study using the tyramide signal amplification technique.

Using the highly sensitive tyramide-signal-amplification technique, we examined immunocytochemically the distribution of neuronal nitric oxide synthase (nNOS) in blood vessels of the rat brain. In contrast to the endothelial isoform, no clear-cut immunostaining could be obtained for the nNOS at the light microscopic level. An occasional faint immunoreaction at the endothelial lining was difficult to interpret. Ultrastructurally, endothelial cells of larger pial vessels, but not those of the parenchyma, revealed immunoprecipitates in their cytosol or attached to cytoplasmic membranes. Several pial and parenchymal vessels showed nNOS-positive perivascular nerves. Immunopositive and negative varicosities were located along the same fiber. The present study and our previous study reveal a clear-cut localization pattern of NOS isoforms in brain endothelium and surrounding tissue, whose particular contribution to the regulation of cerebral blood flow is still uncertain.

Animals↗