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Biomedical subjects

G Wolf

Publications and source records attributed to G Wolf.

At least 343 records · Page 19Linked to original sources
PubMed1995

Results of irradiation treatment in patients with non-resectable oesophageal cancer.

Forty-eight patients with non-resectable cancer of the oesophagus and oesophagogastric junction (Group A: Stage I/II, 32; Group B: Stage III/IV, 16) underwent intraluminal Iridium-192 high dose-rate afterloading therapy (5-7 Gy/session, total dose: 5-21 Gy, mean: 12.4 Gy) and external beam irradiation (Karnofsky > or = 80% 50-60 Gy/2 Gy per day; Karnofsky 60-79%: 30 Gy/3 Gy per day). Durable satisfactory palliation (intake of at least semi-solid food) was demonstrated in 96% of patients. The mean survival for group A was 19.1 months and that for group B, 6.9 months, with a 12-month survival rate of 66% (group A) and 0% (group B) (P < 0.001). Local tumour response and complication rate were significantly dose-related with a predicted response rate of 70.5%, and a complication rate of 50% at ERD 129.3 Gy.

Adult↗
PubMed1995

Angiotensin II-stimulated expression of transforming growth factor beta in renal proximal tubular cells: attenuation after stable transfection with the c-mas oncogene.

Angiotensin II (Ang II) stimulates cellular hypertrophy of cultured murine proximal tubular cells (MCT cells). This Ang II-mediated hypertrophy depends on the endogenous induction and autocrine action of transforming growth factor-beta (TGF-beta). We have previously demonstrated that permanent transfection of MCT cells with the c-mas oncogene, whose protein product encodes a serpentine receptor-like moiety coupled to G proteins without an hitherto identified ligand, changes the hypertrophic actions of Ang II into a proliferative response (Am J Physiol 263: F931-F938, 1992). The present study demonstrated that Ang II failed to stimulate induction of TGF-beta 1 protein in c-mas transfected MCT cells under the control of SV 40 promoter/enhancer (pSV2mas) as measured by mink cell bioassay and specific ELISA for TGF-beta 1. Moreover, in contrast to either wild-type MCT cells or to cells permanently transfected with the SV 40 based expression plasmid only (pSV2 cells), Ang II stimulated gene transcription and mRNA expression of TGF-beta 1 were decreased in c-mas transfected cells. Our findings demonstrate that the Ang II-induced proliferation of c-mas transfected MCT cells most likely depends on failure of TGF-beta 1 induction in these cells. c-mas transfected cells are a useful tool to further investigate the complex relationships between activation of second messengers subsequent to binding of Ang II to AT1-receptors and gene regulation like transcription of TGF-beta 1.

Angiotensin II↗
PubMed1995

[The experiences of a hospital radiology department with outside referrals for the preoperative marking of suspicious breast lesions].

PURPOSE: To outline the experience of a referral radiology department with preoperative localisation procedures on the basic of mammograms obtained by other facilities. MATERIAL AND METHODS: 342 consecutive female patients aged 56.5 +/- 11.9 years underwent preoperative breast localisation procedures prior to surgery. Of these patients 241 had their mammograms obtained in various private practices and 101 in the radiology department. Retrospectively all mammograms were classified by lesions morphology, lesion size and presence or absence of calcifications. RESULTS: The overall benign-to-malignant ratio (B/M-ratio) was 1.7:1. In the referred patient group the B/M-ratio was 1.9:1, compared to a B/M-ratio of 1.3:1 obtained by the radiology department. Referred patients presented significantly (p < 0.001) more often with calcifications that patients from the radiology department. CONCLUSION: Possible factors for the higher B/M-ratio in referred patients are prompt referral to surgical biopsy, misinterpretation of mammograms, failure in the written report, lack of a second opinion and lack of feedback and communication between surgeon, pathologist and radiologist.

Aged↗
PubMed1995

[Treatment of nonspecific hyper-reflectory rhinopathy (vasomotor rhinitis) with capsaicin].

Apart from adrenergic and cholinergic neurones, peptidergic neurones are involved in the autonomic control of nasal mucosa. Their transmitter substances are peptides, so-called "neuropeptides". It is assumed that they are released from peptidergic neurones in the nasal mucosa after irritation of receptors by unspecific stimuli, and are responsible for the symptoms of hyperreactive rhinopathy. Repeated topical application of Capsaicin (8-methyl-N-vanillyl-6-nonenamide) leads to a selective degeneration of peptidergic neurones and desensitisation of its receptors in the nasal mucosa. 123 patients who were suffering from hyperreactive rhinopathy were treated in a prospective study by repeated topical applications of capsaicin solutions in increasing concentrations. A symptom score demonstrated an improvement of the predominating symptoms (nasal congestion, hypersecretion, sneezing) by 62% to 72%. A reduction of unpleasant side effects following application (epiphora, itching, sneezing, mucosal oedema) indicating a desensitising effect could be documented by a symptom score and by active anterior rhinomanometry. Immunohistochemical investigations of nasal mucosa biopsies revealed no reduction of peptidergic neurones within the nasal mucosa, so that a blockage of receptors seems to be responsible for the positive effects. The treatment of hyperreactive rhinopathy with capsaicin or related substances seems to be a promising new way in the treatment of hyperreactive rhinopathy. Further investigations have to prove the site of effect and mechanism of activity of the substance, such as the best modality of application.

Administration, Intranasal↗
PubMed1995

[In vitro studies of the effect of vasoconstrictor nose drops on ciliary epithelium of human nasal mucosa].

We investigated the influence of four nasal decongestants and one preservative on ciliated cells, using cell cultures of human nasal mucosa. These cells were exposed to nasal decongestants in vitro. A fast decrease in ciliary beat frequency was seen during naphazoline and oxymethazoline application which was fully reversible after naphazoline. There was only a minimal decrease in ciliary beat frequency during application of phenylephrine and xylomethazoline decongestants. The preservative benzalkoniumchloride caused an irreversible decrease in ciliary beat frequency which was concentration dependent. We therefore recommend nasal decongestants which contain xylomethazoline or phenylephrine. If the preservative benzalkoniumchloride can not be substituted by newer less harmful substances, it should be added in minimal concentrations.

Dose-Response Relationship, Drug↗
PubMed1995

Pregnancies following pre-conception diagnosis of common aneuploidies by fluorescent in-situ hybridization.

Chromosomal aneuploidies contribute considerably to the low pregnancy rate in in-vitro fertilization (IVF). The objective of this experimental work was to explore the possibility of detecting common aneuploidies in oocytes by polar body sampling. The study included 45 infertile patients of advanced maternal age participating in an IVF programme. The first polar body was removed prior to fertilization or both the first and second polar bodies were removed after fertilization and studied by fluorescent in-situ hybridization (FISH) using chromosome-specific probes for chromosomes X, 18 and/or 13/21. Of 155 oocytes with FISH results, 36 demonstrated chromosomal abnormalities. Of 119 oocytes predicted to be free from aneuploidy of chromosomes X, 18 and/or 13/21, 72 were normally fertilized, cleaved and transferred in 23 treatment cycles, which resulted in two healthy deliveries and three ongoing pregnancies confirmed to be unaffected by chorionic villous sampling. The method may appear useful for the detection of oocytes with common chromosomal aneuploidies in IVF patients of advanced maternal age.

Adult↗
PubMed1995

The effect of fasting and fructose and glucose infusion on gluconeogenesis and triose phosphate flux in rats in vivo.

Gluconeogenesis was measured quantitatively by mass isotopomer distribution analysis in rats in vivo through determination of the isotopic enrichment of the pool of hepatic triose phosphates, the immediate precursors of glucose, using primarily [2-13C]glycerol infusion after fasting, and following fructose and glucose infusion. The results showed that the liver controls gluconeogenesis, the metabolic sources and disposal of triose phosphates, and the contribution of glucose from glycogen in response to alterations in substrate availability.

Animals↗
PubMed1995

Retinol transport and metabolism in transthyretin-"knockout" mice.

Mice were made deficient in transthyretin (TTR), the protein that normally transports plasma retinol complexed with retinol-binding protein (RBP), by targeted mutagenesis (TTR-knockout mice). The TTR- mice were healthy and fertile, despite extremely low plasma retinol and RBP levels (6% of wild type). Circulating retinoic acid was 2.3 times that of wild-type controls. Liver levels of RBP were 60% higher in the TTR-mutants compared to wild-type mice, suggesting that lack of TTR may block secretion of RBP-retinol from liver.

Animals↗
PubMed1995

The enzymatic cleavage of beta-carotene: still controversial.

The enzyme beta-carotene-15,15'-dioxygenase from guinea pig intestinal mucosa was found to cleave beta-carotene and produce 2 mol of retinal for 1 mol of beta-carotene. However, extensive evidence exists also for random (excentric) cleavage, resulting in retinoic acid and retinal, with a preponderance of apocarotenals formed as intermediates.

Animals↗
PubMed1995

A regulatory pathway of thermogenesis in brown fat through retinoic acid.

Thermogenesis in brown adipose tissue is achieved by the enzyme that uncouples the respiratory chain from oxidative phosphorylation. This enzyme is regulated by the sympathetic nervous system and, as recently discovered, by transcriptional regulation through retinoic acid (RA). Thus, RA is involved in heat production and, hence, in the regulation of energy balance.

Adipose Tissue↗
PubMed1995

ANG II is a mitogen for a murine cell line isolated from medullary thick ascending limb of Henle's loop.

A murine SV40-transformed renal epithelial cell line derived from medullary thick ascending limb of Henle's loop (MTAL) was established and characterized by morphology, antigen expression, and biochemical criteria. These MTAL cells express a single class of high-affinity receptors for angiotensin II (ANG II) and transcripts for the AT1 subtype of ANG II receptors. ANG II, in a dose-dependent manner, induced proliferation of MTAL cells. This observation is in striking contrast to syngeneic proximal tubular cells in which it was previously shown that the peptide induced cellular hypertrophy and slightly inhibited proliferation [G. Wolf and E. G. Neilson. Am. J. Physiol. 259 (Renal Fluid Electrolyte Physiol. 28: F768-F777, 1990]. The AT1-receptor antagonist losartan (10(-6) M), but not an AT2-receptor antagonist, blocked the mitogenic effects of ANG II in MTAL cells. Coincubation of quiescent MTAL cells with ANG II and 5% fetal calf serum further increased proliferation compared with cells grown only in serum. In contrast to proximal tubular cells, ANG II failed to induce transforming growth factor-beta 1 mRNA and protein synthesis in MTAL cells. Our data collectively suggest that ANG II is a mitogen for MTAL cells in vitro. Therefore, epithelial cells derived from different parts of the nephron, even when transformed with SV40 virus and while under cell culture conditions, exhibit a distinct pattern of growth behavior after stimulation with ANG II.

Angiotensin II↗
PubMed1995

Atrial natriuretic peptide stimulates the expression of transforming growth factor-beta in cultured murine mesangial cells: relationship to suppression of proliferation.

Atrial natriuretic peptide (ANP) is a growth suppressor for a variety of different cell types including cultured mesangial cells. This study examined the effects of ANP on the expression and synthesis of transforming growth factor-beta (TGF-beta) in a cultured murine mesangial cell line (MMC). Full-length rat ANP as well as 8-bromo-cGMP, but not ring-deleted ANP analogues, induced, in a dose-dependent manner, TGF-beta 1 mRNA expression in MMC. Moreover, full-length ANP and 8-bromo-cGMP stimulated the synthesis and release of TGF-beta 1 into cell culture supernatants as measured by a specific enzyme-linked immunosorbent assay and mink cell bioassay. The induction of TGF-beta 1 by 10(-6) M ANP and 10(-4) M 8-bromo-cGMP for 24 h was also documented by western blotting of MMC culture supernatants. However, transient transfection studies in MMC with three different murine TGF-beta 1 reporter gene constructs revealed only little stimulation of activity after ANP treatment, suggesting that posttranscriptional activation may mainly contribute to TGF-beta mRNA induction. Functional studies demonstrated that the ANP-mediated inhibition of mitosis, induced by 5% fetal calf serum, is partly abolished in the presence of a neutralizing anti-TGF-beta 1-3 antibody. In addition, the antiproliferative effects of exogenous 8-bromo-cGMP are also attenuated by anti-TGF-beta 1-3 antibody. These findings indicate that ANP stimulates TGF-beta expression in MMC and that the antiproliferative effects of ANP in this cell line may be mediated, at least to some extent, by the endogenous induction of TGF-beta. An increase in intracellular cGMP is most likely the mediator of this TGF-beta 1 induction. Considering the fibrogenic effects of TGF-beta, these findings may be important in the development of glomerulosclerosis in situations with an increase in local or systemic ANP.

Animals↗
PubMed1995

Cellular mechanisms of tubule hypertrophy and hyperplasia in renal injury.

Tubular cells can either unergo hyperplasia or hypertrophy, two totally different growth responses. Hyperplasia with mitogenesis of tubular cells plays a central role in the regeneration of functional tubular epithelium subsequent to acute tubular necrosis. Several growth factors acting in concert are involved in this proliferative response of tubular cells. The molecular mechanisms how mitogenic signals are transduced to the nucleus are relatively well characterized. Complex oscillation patterns of cell cycle-associated proteins like cyclins and various kinases are pivotal for the progression of quiescent tubular cells through mitosis. In contrast to the mitogenic growth response of regenerating tubular cells, cellular hypertrophy is less well understood. Hypertrophic cells are arrested in the G1-phase of the cell cycle and increase their size, protein and RNA content, but do normally not replicate their DNA. Such an enlargement of tubular cells often occurs in more chronic situations of renal damage in which remnant nephrons adapt their function to the increasing need. However, evidence exists that hypertrophic tubules are finally joined into the process of maladaptation of renal function leading to tubular atrophy, interstitial scarring, and progression of renal disease. It appears that transforming growth factor-beta is involved in the hypertrophy of tubular cells. The present review will address more recent progress in understanding the mechanism of tubular growth at a cellular level. A better knowledge of the molecular factors may ultimately lead to therapeutic strategies preventing the progression of renal and speeding up renal recovery after acute renal failure.

Animals↗
PubMed1995

The endoscopic endonasal surgical technique in the treatment of chronic recurring sinusitis in children.

Chronic recurring sinusitis (CRS) is a difficult diagnosis to make in the paediatric patient. However, increased awareness by physicians and improved technology are contributing to an increasing frequency of this diagnosis. Children with their immature development of the paranasal sinuses and immunological systems present special problems in the treatment of CRS. Concern must be given to potential alteration of the development of the paranasal sinus system and tooth buds in the maxilla by a surgical procedure in children. Various surgical procedures have been recommended in the past in the treatment of CRS failing medical management. A review of 124 paediatric patients undergoing endoscopic endonasal sinus surgery using the technique of Messerklinger and Stammberger in the treatment of CRS over an 11-year period is presented. A detailed questionnaire regarding patient's satisfaction and symptomatic relief has been sent to all patients. The results indicate a successful outcome from this technique and a high level of patient satisfaction. No complications such as CSF leak or orbital injury have been encountered, and no evidence of altered facial growth and development has been noted. We find the endoscopic endonasal technique to be a safe and effective method in the treatment of children with CRS failing medical management.

Child↗
PubMed1995

Chromatin structure analysis based on a hierarchic texture model.

The quantification of chromatin structures is an important part of nuclear grading of malignant and premalignant lesions. In order to achieve high accuracy, computerized image analysis systems have been applied in this process. Chromatin texture analysis of cell nuclei requires a suitable texture model. A hierarchic model seemed to be most compatible for this purpose. It assumes that texture consists of homogeneous regions (textons). Based on this model, two approaches to texture segmentation and feature extraction were investigated using sections of cervical tissue. We examined the reproducibility of the measurement under changing optical conditions. The coefficients of variations of the texture features ranged from 2.1% to 16.9%. The features were tested for their discriminating capability in a pilot study including 30 cases of cervical dysplasia and carcinoma. The overall classification accuracy reached 65%. This study presents an automated technique for texture analysis that is similar to human perception.

Carcinoma in Situ↗
PubMed1994

[Magnetic resonance imaging of breast implants. Significance compared to mammography and ultrasonography].

Magnetic resonance imaging (MRI), mammography and ultrasonography were performed in 44 consecutive women (mean age 45 [29-70] years) with a total of 73 silicone breast implants. The implant had been inserted after mastectomy for cancer in 15 patients, for cosmetic breast augmentation in 29. MRI proved to be superior to the other two imaging modalities with respect to assessing implant content, capsule and surrounding tissues. In 39 patients MRI clearly demarcated the implant from the residual breast tissue. But in four patients the lateral MRI assessment was impaired by phase artefact and in one other by movement artefacts in a restless patient. Implant thickness was underestimated by mammography and ultrasonography compared with MRI. In nine cases mammography showed retromammary parenchyma, while MRI did so in 20. The posterior wall of the implant was visualized by mammography in only one patient, but in all of them by MRI. Ultrasonography failed in all patients to show the entire implant circumference. In three cases MRI was the only imaging method which revealed a defect in the implant capsule with extrusion of silicone.

Adult↗
PubMed1994

Ultrastructural distribution of NADPH-diaphorase in cortical synapses.

To elucidate the role of nitric oxide (NO) in synaptic structures, the ultrastructural localization of the enzyme NO synthase (NOS), based on the cytochemical NADPH-diaphorase staining, was studied in neocortical and hippocampal neuropil areas. For the localization of NADPH-diaphorase activity a special tetrazolium salt (BSPT) was applied. BSPT-formazan, the osmiophilic reaction product, was found to be attached to endomembranes, predominantly the endoplasmic reticulum. Quantitative studies on synaptic regions revealed that mainly presynaptic areas (41% in hippocampus, 38% in neocortex) showed labelling. Postsynaptic regions were only exceptionally labelled by BSPT-formazan (3% in hippocampus, 5% in neocortex). The present findings support the view that NO may be involved in diverse synaptic functions acting preferentially from the presynaptic side.

Animals↗