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Biomedical subjects

B Riedel

Publications and source records attributed to B Riedel.

At least 19 recordsLinked to original sources
PubMed1992

Interaction between heparin and acetylsalicylic acid on gastric mucosal and skin bleeding in humans.

The haemorrhagic effect of unfractionated heparin and of the low molecular weight heparin, enoxaparin, on gastric mucosal bleeding induced by acetylsalicylic acid (ASA) and on skin bleeding induced by the Simplate technique was investigated in healthy human volunteers. Endoscopic estimation of gastric bleeding by visual analogue scores was more sensitive than biochemical quantitation of blood in the gastric washing by a modified HaemoQuant method. Contrary to what was expected, the ASA-induced gastric mucosal bleeding was not increased by heparin pretreatment, whereas heparin in combination with ASA, but not ASA alone, significantly increased the skin bleeding time. In the interaction with ASA, enoxaparin and unfractionated heparin appeared to act similarly.

Adult↗
PubMed1992

Haemorrhagic effect of enoxaparin, a low molecular weight heparin. Comparison with unfractionated heparin in humans.

The haemorrhagic effects of unfractionated heparin (UFH) and the low molecular weight heparin (LMWH) enoxaparin were investigated and compared in the gastric mucosa (haemorrhage induced by biopsy) and skin (haemorrhage induced by Simplate) of 12 healthy volunteers. Administration of UFH and LMWH (given in a dose of 75 anti-Xa U/kg intravenously) increased median gastric bleeding time (3.5 min) and geometric mean blood loss (11.5 microliters) to 19 min (p = 0.00003) and 54.1 microliters (p = 0.0021) after UFH and to 13 min (p = 0.008) and 29.0 microliters (p = 0.275) after LMWH. Median skin bleeding time (4.25 min) increased to 6.0 min after UFH (p = 0.003) and to 6.75 min after LMWH (p = 0.0008). Mean heparin activity in plasma was 20% higher after LMWH than after UFH. The calculated gastric bleeding time to heparin activity ratio was significantly lower for LMWH than for UFH (p < 0.05).

Adult↗
PubMed1992

Epidermal growth factor up-regulates intestinal Na+/H+ exchange activity.

The present studies were designed to examine the regulation of Na+/H+ exchange activity by epidermal growth factor (EGF) in an in vitro system. Na+/H+ exchange activity was determined in brush-border membranes isolated from rat jejunal enterocytes incubated with epidermal growth factor and a number of second messengers. EGF at physiological concentrations stimulated Na+/H+ exchange activity without affecting vesicle size. The stimulation of Na+/H+ activity was the result of increasing Vmax of Na+/H+ (6.0 +/- 0.4 compared with 3.3 +/- 0.27 nmol/mg protein/5 sec, P < 0.01). Km values of the Na+/H+ exchanger in brush-border membrane from cells stimulated with EGF and controls were similar (16.0 +/- 3.0 vs 13.0 +/- 3.0, respectively). Na+/H+ activity was inhibited by phorbol esters, calmodulin, and cyclic AMP. The effects of EGF, calmodulin, cyclic AMP, and phorbol esters were dependent on ATP, because depleting the cells from ATP masked the effects on Na+/H+ exchange activity. The results suggest that EGF stimulates Na+/H+ exchange activity in the enterocytes. This stimulation is most likely not via activation of the phosphatidylinositol pathway.

Adenosine Triphosphate↗
PubMed1990

[The subacute and subchronic toxicity of chlorophacinone in Japanese quail (Coturnix c. japonica)].

Accordingly to the subacute toxicity of chlorphacinone to Japanese quail (LC 50: 60 mg/kg feed), the uptake of Delicia-chlorphacinone-baits for several days can be lethal to birds as a matter of principle. A subchronic study resulted in a "no-observed-effect-level" of 1 mg chlorphacinon/kg feed. Reproduction is not affected until dose levels which resulted in lethality or are accompanied by physiological changes (coagulability of blood, microcytic anaemia). Increased sensibility of descendants to chlorphacinone cannot be derived from the findings.

Animals↗
PubMed1979

Novel antiviral activity found in the media of Sindbis virus-persistently infected mosquito (Aedes albopictus) cell cultures.

Aedes albopictus (mosquito) cells persistently infected with Sindbis virus for a period of 6 months release into the medium a low-molecular-weight material capable of specifically reducing the yields of Sindbis virus during the "acute phase" of infection in mosquito cells. The antiviral activity was produced in detectable levels at 3 days after infection, and its concentration in the extracellular medium increased thereafter. The antiviral activity was inactivated by treatment with the enzyme protease K and heat. It was not activated by treatment with antibody prepared against extracts of Sindbis virus-infected BHK-21 cells. The antiviral activity differs from interferon produced by vertebrate cells in that it is virus specific as well as cell specific.

Aedes↗
PubMed1977

Morphogenesis of vesicular stomatitis virus: electron microscope observations with freeze-fracture techniques.

The morphogenesis of vesicular stomatitis virus was examined using freeze-fracture techniques, and the results obtained were compared with those from previously published experiments carried out with influenza viruses and togaviruses. The process of conversion of the host cell plasma membrane into the vesicular stomatitis virus envelope was accompanied by a loss of the intramembranal particles abundant in cell membranes. Frequently a dense accumulation of intramembranal particles could be seen at the base of the developing virion, suggesting that these structures might play some role in the generation of viral envelope. In addition to the viral structures that were seen to develop in the classical fashion, with their long axis perpendicular to the cell surface, structures were also found that suggested the initiation of a process similar to budding, with the long axis of the viral capsid parallel to the plasma membrane. In this situation, as in the "perpendicular" process, intramembranal particles were excluded from the viral structure, and an accumulation of these particles could be seen adjacent to the developing viral membrane.

Cell Line↗
PubMed1977

Role of extracellular virus on the maintenance of the persistent infection induced in Aedes albopictus (mosquito) cells by Sindbis virus.

Sindbis virus infection of cultured mosquito cells was found to have no effect on the growth of these cells; instead, a persistent infection of the culture followed an initial acute phase of rapid virus synthesis. Nearly all of the cells in the acute stage of infection were found to actively release virus in an infectious-center assay and to contain significant amounts of virus antigen as determined by immunofluorescence. Cells in the persistent phase of infection released few virions into the media, and only a small percentage of the cultured cells could be demonstrated to contain detectable amounts of virus antigen by immunofluorescence assay. In spite of the fact that nearly 100% of the cells in the persistent phase of infection were found to be virus negative by the two assays described above, the culture as a whole totally excluded the expression of superinfecting virus, as did cells in the acute phase, suggesting that most of the persistently infected cells did, indeed, contain virus information. Prevention of reinfection of the cells in the persistent phase by eliminating extracellular virus resulted in a curing of the culture such that it responded to infection by added virus much as would an uninfected culture.

Aedes↗
PubMed1976

Denudation of the urinary bladder mucosa in the cat by formaldehyde.

Chemical Stripping of the urinary bladder mucosa was studied in 38 cats using 5 to 25% formaldehyde solutions. The contact time varied from 1 to 20 min. With a 20% solution and contact time of 1 min, total denudation was possible without necrosis of subepithelial layers. In such cases, complete reepithelialisation and normal bladder dynamics were seen within 3-4 weeks after formaldehyde instillation. Signs of formaldehyde intoxication due to vesical resorption were not observed.

Animals↗
PubMed1976

Investigations of urinary stone formation following persorption.

Persorption is the excretion in urine of particles that have been absorbed (persorbed) from the gastrointestinal tract. In experiments with rats the effect of Herbst was combined with the production of renal calcium oxalate sediments by the oral administration of ethylene glycol and acidification with ammonium chloride. We used this method to investigate whether persorbed corpuscula may represent nuclei of crystallization in the formation of renal calculi. Lead sulfide, zirconium silicate and 45Ca-labeled calcium oxalate crystals were used as persorbable model bodies. It became apparent that orally supplied lead sulfide and zirconium silicate crystals could be found in the urine and the kidneys but they did not function as crystallization centers in the calcium oxalate sediments. However, radioactive labeled calcium could be demonstrated histoautoradiographically within the renal concrements. Our experiments showed that persorbed calcium oxalate crystals can work as nuclei for stone formation.

Ammonium Chloride↗
PubMed1975

Replacement of urinary bladder wall in the cat by autologous x-ray treated full thickness skin graft.

A partial urinary bladder resection was performed in 25 female cats. The defect was replaced with an X-ray treated autologous full thickness skin graft. This graft was shown to be an appropriate foundation for the rapid regeneration of transitional cell epithelium which was proven to be present after 4 weeks. Smooth muscle fibres were present in all cases after 12 weeks. Postoperatively, bladder capacity was adequate without evidence of incrustation or ossification. No changes were seen in the upper urinary tract. Compared to other types of autologous bladder wall replacement this method is simple and warrants clinical investigation.

Animals↗
PubMed1975

[Cytological examination for determining the therapeutic response of prostatic carcinoma to hormonal therapy (author's transl)].

51 patients with proven prostatic carcinoma stage B-D underwent control aspiration biopsy after hormonal therapy using the Franzén needle. The malignancies were classified into three grades and the cytological findings were compared with the malignancy grade of the tumor and the clinical course. At the same time the caryopycnotic index, as determined by swabs from the urethral fossa navicularis was measured in order to determine the serum estrogen level. As the result of the anti-androgenic therapy one finds degenerative changes in the tumor cells. The results showed that the poorer the histological differentiation of the tumor, the lesser was the cytological change. Only 6 of 34 patients with a good hormonal effect showed a progression of the tumor, whereas 16 of 17 patients with a poor hormonal effect showed clinical progression. 70% of the cases demonstrated agreement between the clinical course and the caryopycnotic index. No correlation was found between the caryopycnotic index and the histological grade of the tumor.

Adenocarcinoma↗
PubMed1975

[First experiences with the incontinence operation Kaufman III (implantation of a silicongel prothesis covered with polyurethanfoam) (author's transl)].

For operative treatment of urinary incontinence after TUR of the prostate, radical prostatectomy and meningocele operation the silicongel prothesis described by Kaufman was implanted. By compression of the bulbus urethrae a sealing effect was achieved. The pressure of the detrusor opens the urethra enough to enable urination. Seven patients were operated. The results directly after the operations were: three very good, two good and two bad. We achieved very good results by implantation of the prothesis "large" -in the case of the two bad operative results we used the "medium" size prothesis. By filling these protheses with 5 ml liquid they proved to be leaky. One of these was operatively removed and replaced by the size "large". This patient later developed a urethra stricture in the implantation region with overflow bladder after having been continent. By internal urethrotomy this condition was restored; except for minor dripping after miction the patient was continent. The prothesis of a direct postoperative continent patient had to be filled. This led to and infection with the development of fistula. The prothesis had to be removed. A further patient who sat on a hard object developed a lesion of the prothesis with resulting incontinence. At least six months after the operations four patients remained continent and three incontinent.

Aged↗
PubMed1975

Experimental urinary stone formation following persorption.

The 'effect of Herbst' was combined with the production of renal calcium oxalate sediments by oral administration of ethyleneglycol and acidification with NH4Cl. This investigation was made to see whether persorbed bodies may form nuclei in crystallization in the genesis of stone. Lead sulphide crystals and 45Ca-labelled calcium oxalate crystals were used as persorbable model bodies. It became apparent that lead sulphide crystals given by mouth could be found both in the urine and kidneys, but these did not form nuclei in calcium oxalate sediments. Radioactive-labelled calcium, however, could be proved histoautoradiographically within the renal concretions. Our experiments showed that persorbed calcium oxalate crystals can represent nuclei for stone formation.

Ammonium Chloride↗