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Biomedical subjects

G Rühl

Publications and source records attributed to G Rühl.

11 recordsLinked to original sources
PubMed1994

Methylation sensitivity of the enhancer from the human papillomavirus type 16.

The human papillomavirus type 16 is associated with anogenital cancer. Transcription of the viral transforming genes E6 and E7 is under the control of an epithelial cell type-specific enhancer. In the enhancer core, we have identified a regulatory element that is recognized by a novel nuclear factor named MSPF (methylation-sensitive papillomavirus transcription factor). Mutating the MSPF binding site strongly affects the enhancer activity. The MSPF recognition sequence 5'-ATGCGNNNNCGCCT-3' contains two CpG dinucleotides, potential targets for 5-cytidine methylation. DNA recognition by MSPF is strictly methylation-sensitive, since introduction of 5-methylcytidine into either CpG abolishes complex formation. Moreover, CpG methylation of the MSPF binding site suppresses the activity of the enhancer and of the MSPF enhanson subfragment in vivo. In the cervical carcinoma cell line CaSki, which has integrated multiple transcriptionally inactive human papilloma virus 16 genomes, a few of the viral genomes are methylated at the MSPF binding site. These findings suggest that viral transcription can be suppressed by methylation of the regulatory region, an event that prevents binding of the cellular transcription factor MSPF.

3T3 Cells↗
PubMed1992

Omeprazole-induced pseudohypertrophy of gastric parietal cells.

Paraffin-embedded and haematoxylin-eosin-stained sections of biopsy material obtained from patients taking omeprazole reveal a characteristic "hypertrophy" of the parietal cells; these are taller than the chief cells, and project, with convexly bulging apical cell membrane, into the lumen of the body glands, producing a serrated internal gland profile. We have found this phenomenon in 92.9% of 198 patients with non-operated stomachs. After Billroth I or II resection, this phenomenon was found in the body mucosa of the stomach remnant in only 35.3% of the cases (n = 17). The specificity of the diagnosis "hypertrophy" of the parietal cells under omeprazole therapy was 89.4%, the sensitivity 91.0%. A comparative morphometric analysis in forceps biopsy material investigated after paraffin and epoxide embedding, showed that this "hypertrophy" was a pseudohypertrophy. Apparently, as a result of an increase in intracytoplasmic secretory canaliculi, the gastrin-stimulated parietal cell shrinks less than the non-stimulated parietal cell. This pseudohypertrophy of the parietal cells can readily be used to monitor the compliance of the patient prescribed omeprazole. A question that has yet to be clarified is how quickly pseudohypertrophy develops, and how long it takes to regress after discontinuation of omeprazole. The phenomenon can also be seen in active autoimmune gastritis with no atrophy of the gland, since the parietal cell antibody also binds selectively to the proton pump of the parietal cell.

Cell Membrane↗
PubMed1991

[Diagnosis of Helicobacter pylori colonization of the gastric mucosa. A prospective comparative study of direct test methods and validation of a new urease test].

A prospective study including 119 patients submitted for routine endoscopy of the upper gastrointestinal tract was initiated to compare three commercial biopsy urease tests with regard to sensitivity and specificity in detecting Helicobacter pylori colonization of the gastric mucosa and their reaction velocity. Specific culture, microscopy after staining with methylene-blue, histologic search after modified Giemsa staining and the combined results of culture and histology ("true standard") served as reference methods. The sensitivity and specificity of all three tests were high: Angass urease test 92.0%/97.7%, Telen-Quick test 94.7%/100%, CLO-test 94.7%/100% (analysis of one antrum and one body biopsy in a single test kit). Telen-Quick and CLO-tests reacted faster than the Angass urease test, but a period of 24 hours was necessary for all three tests to detect "true negatives". Histology and microscopy were reliable reference methods concerning sensitivity and specificity, while culture was characterized by inferior sensitivity (78.6%) and high specificity (100%).

Adolescent↗
PubMed1988

[Importance of contrast medium administration in determining the age of traumatic renal hemorrhage by NMR tomography--experimental results].

In eleven Han-Wistar rats, experimental renal haematomas were produced and scanned by magnetic resonance tomography at two hours to 21 days. Bleeding during the first three or four days showed prolongation of T1 and T2 relaxation times. On subsequent days there was shortening of the T1 and T2 times. Gadolinium DTPA produced a marked effect in the second to fourth day following the trauma, if the examination was carried out 90 to 120 minutes after the administration of contrast medium. Gadolinium can be used in determining the age and clarifying the differential diagnosis of an bleeding if there is clinical support.

Animals↗
PubMed1987

[Nuclear magnetic resonance tomographic studies following experimental ligation of the renal artery in rats].

MR was carried out on 22 Han-Wistar rats in relation to ligature of the left renal artery; measurements were obtained before the operation and at two, four, eight and thirty-six hours afterwards. Significant increase in T2 relaxation of the left cortex was observed after thirty-six hours and increased T2 of the medulla on the operated side after two hours. T1 relaxation time in the cortex was also prolonged, but the medulla showed no definite change. Following the operation, there was an increase in the size of the opposite kidney after eight hours; on the operated side, the cortex increased, but the medulla decreased. The results indicate that MR is a very sensitive method for demonstrating renal artery occlusion at an early stage.

Animals↗
PubMed1987

[Nuclear spin tomography and computerized tomography in malignant hypernephroma].

Forty patients with histologically confirmed hypernephromas were examined by MR and CT. As regards T-staging, MR had an accuracy of 97% and CT of 91%; for N-staging, MR had an accuracy of 85% and CT of 91% and, with regard to infiltration of the renal vein, MR was correct in 88% of cases and CT in 81%. MR was most accurate in the pre-operative assessment of tumour spread, demonstrating caval involvement in 100% and lymph node metastases in 97%. On the other hand, infiltration of the renal pelvis could be assessed in only 65% of cases; in 27% the assessment was not possible and in 8% one could not be certain. CT proved to be at its best for staging of lymph nodes, but in 15% it was not possible to identify infiltration of the renal vein. MR was not greatly superior to CT in the preoperative diagnosis and staging of hypernephromas.

Carcinoma, Renal Cell↗
PubMed1987

[NMR tomographic studies in experimental renal vein ligation].

Experimental ligation of the renal veins in rats indicate highly significant and characteristic changes within two hours, consisting of significant prolongation of T2 relaxation time in the cortex and T2 shortening in the medulla. In addition, there is a considerable increase in the size of the kidney, due to swelling of the cortex. T2 prolongation of the cortex is most marked between 30 hours and two to four days after ligation of the vein. In the following weeks there is a return to normal. T2 of the medulla at two to three weeks after ligation shows highly significant reduction compared with the normal side and, at this time, the size of the experimental kidney is significantly less than the opposite kidney. These results indicate that magnetic resonance tomography is a highly sensitive method for the early demonstration of renal vein thrombosis.

Animals↗
PubMed1985

[Acute liver necrosis caused by valproate].

After treatment with valproic acid a 19-year-old female patient with Friedreich's ataxia and generalised epilepsy died following acute hepatic failure with massive lactacidosis. The clinical symptoms were characterised by hyperventilation, increasing loss of consciousness and shock, leading to treatment-resistant hepatic coma. Morbid anatomy showed extensive confluent lytic necroses of liver acini with accentuation of centrolobular and intermediary structures as well as small and medium-sized fatty degeneration increasing from the periphery towards the centre. The disease picture is quite characteristic for being caused by valproic acid. As a safety measure liver function tests should be done should prodromal symptoms such as anorexia, weakness and apathy arise. If necessary the dosage has to be reduced or medication stopped. Serum valproic acid levels should remain in the lower half of the therapeutic range.

Adult↗