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Biomedical subjects

E Walter

Publications and source records attributed to E Walter.

At least 91 records · Page 5Linked to original sources
PubMed1990

Fate of interleukin-6 in the rat. Involvement of skin in its catabolism.

Iodinated recombinant human interleukin-6 (125I-rhIL-6) was intravenously injected into rats and its fate was studied during 24 h. Between 10-20 min after a single-dose injection, 125I-rhIL-6 accumulated in liver as previously reported [Castell et al. (1988) Eur. J. Biochem. 177, 357-361]. After 1 h, the radioactivity disappeared from the liver and accumulated in skin, reaching 35% of injected 125I-rhIL-6 5-8 h after injection. No comparable accumulation of radioactivity was found in skin when [125I]iodide or rat serum 125I-albumin was administered. Finally the radioactivity was detected as [125I]iodide in urine. Autoradiographic analysis of skin sections 5 h after 125I-rhIL-6 injection showed radioactivity in the interstitium. When the experiments were carried out with [35S]rhIL-6, essentially the same results were obtained: a decrease in radioactivity in the liver after 20 min, and a substantial increase in skin 7 h after injection. In vitro experiments showed that 125I-rhIL-6 is degraded by rat and human fibroblasts, whereas no degradation was observed with rat hepatoma cells (Fao) or human hepatocytes. These observations suggest the involvement of skin in the catabolism of IL-6.

Animals↗
PubMed1990

[Chronic hepatitis B: diagnostic value of hepatitis-B-virus DNA analysis in serum and liver tissue].

The diagnostic value of hybridization analyses for the detection of hepatitis B virus (HBV) DNA in serum and liver tissue was investigated in 79 patients with chronic liver disease. Active viral replication was demonstrated by the detection of HBeAg or HBV-DNA in serum or liver tissue. However, HBV-DNA was also detected in the absence of HBeAg in serum. No correlation was found between the presence of HBV-DNA in serum or liver tissue and clinico-chemical or histological disease. In HBsAg-negative patients no HBV-DNA was detected in serum or liver tissue. These data indicate that serological markers are sufficient for the diagnosis of HBV infection. However, detection of HBV-DNA in serum or active viral replication in liver tissue is important in selecting patients for antiviral therapy (e.g. interferon) and monitoring its efficacy.

Adolescent↗
PubMed1990

Long-term follow-up of posttransfusion and sporadic chronic hepatitis non-A, non-B and frequency of circulating antibodies to hepatitis C virus (HCV).

The natural course of chronic hepatitis non-A, non-B (HNANB) was documented for 3-20 yr (mean 8 yr) in 86 patients, who attended our special ambulance between 1981 and 1988. Sixty five of the 86 patients (75%) were positive for circulating antibodies against hepatitis C virus (HCV) (anti-HCV). Twenty four patients had chronic posttransfusion (PT)-HNANB (18 anti-HCV-positive; 75%), and 62 patients had sporadic (S)-HNANB (47 anti-HCV-positive; 75%). Twenty nine per cent of patients with chronic PT-HNANB had sustained normalization of aminotransferases after a period up to 5 yr, 55% demonstrated chronic persistent hepatitis (CPH) and 16% progressed to chronic active hepatitis (CAH) with transition to cirrhosis. In the group with chronic S-HNANB, 2% of patients showed remission, 43% had stable CPH and 55% progressed to CAH or cirrhosis. However, development of cirrhotic complications required many years. Transition from CAH to CPH or remission was not observed. The results indicate that 75% of both patients groups with chronic PT- and S-HNANB are infected with the same agent, of which antibodies are detected by the new anti-HCV assay. There was no statistical association between the severity of the disease and the presence of anti-HCV. The different proportions of progressive courses in chronic PT- and S-HNANB might be explained by the patient recruitment.

Blood Transfusion↗
PubMed1990

[Non-cirrhotic portal hypertension].

A chronic increase of the portal venous pressure is not only a sequel of liver cirrhosis. There is a large group of different diseases leading to "non-cirrhotic portal hypertension". Clinical presentation, diagnosis and treatment are discussed. The discrimination between cirrhotic and non-cirrhotic portal hypertension is important for the understanding of differences in clinical signs and course of the diseases, however.

Arteriovenous Fistula↗
PubMed1989

[Spontaneous remission of lung metastases in renal cell carcinoma].

Pulmonary metastases were first noted in a 47-year-old man, 15 months after a radical right nephrectomy and local radiotherapy. They progressed over the subsequent ten months despite progestagen administration. But they regressed slowly after the progestagen had been discontinued so that eight months later they were no longer demonstrable radiologically. The remission has so far persisted for 3 1/2 years.

Carcinoma, Renal Cell↗
PubMed1989

Duck hepatitis B virus: cloning and subcloning of the viral genome.

In the course of studies on the biology of hepadnavirus infections, duck hepatitis B virus (DHBV) DNA was isolated from the serum of a German Pekin duck. Viral DNA was cloned in E. coli using pBR 322 DNA as a vector. The cloned DHBV DNA F 1-6 was characterised by restriction enzyme analyses. DHBV DNA F 1-6 was subcloned in both orientations in plasmid pSP 65 to produce strand-specific RNA probes. These probes specifically identified asymmetrically replicating nascent minus-strand DHBV DNA species or plus-strand viral RNA transcripts.

Animals↗
PubMed1988

Plasma clearance, organ distribution and target cells of interleukin-6/hepatocyte-stimulating factor in the rat.

The plasma half-life of recombinant human interleukin-6 (rhIL-6) was determined in rats by measuring the disappearance of the biological activity as well as of the radioactivity of 125I-rhIL-6 from the circulation. The kinetics of clearance were biphasic. It consisted of a rapid initial disappearance corresponding to a half-life of 3 min, and of a second slow one corresponding to a half-life of about 55 min. By cellulose-acetate electrophoresis it was shown that rhIL-6 binds to a plasma protein resulting in a complex migrating in the beta-gamma region; 20 min after intravenous injection, about 80% of the 125I-rhIL-6 that had disappeared from the circulation was found in the liver. 125I-rhIL-6 was exclusively localized on the surface of parenchymal cells suggesting the existence of an interleukin-6 receptor on the hepatocytes.

Animals↗
PubMed1988

Duck hepatitis B virus: DNA polymerase and reverse transcriptase activities of replicative complexes isolated from liver and their inhibition in vitro.

The duck hepatitis B virus (DHBV)-associated activities of reverse transcriptase and DNA polymerase and their inhibition in vitro were studied. Replicative complexes (RCs) were isolated from DHBV-infected liver by gel chromatography followed by sucrose gradient centrifugation. The RCs were detected by dot blot hybridization, using radiolabeled cloned DHBV DNA as a probe, and by the incorporation of 32P-TTP in the presence of dATP, dCTP, dGTP, and Mg2+ (endogenous DNA polymerase activity). The endogenous DNA polymerase activity associated with RCs was further studied using exogenous templates: reverse transcriptase and DNA polymerase activities were demonstrated using as substrates 32P-TTP and poly(rA) p(dT)12 or poly(dA) p(dT)12-18, respectively. Both activities were biochemically characterized. Their inhibition by various antiviral agents was studied in vitro: actinomycin D, ara-ATP, aphidicolin, suramin, chloroquin, and phosphonoformate. Among these, suramin, chloroquin, phosphonoformate, and ara-ATP were shown to be potent inhibitors of viral reverse transcriptase and DNA polymerase. Studies are now in progress to establish their antiviral activity in vivo.

Animals↗
PubMed1988

[Conventional x-ray diagnosis of the knee joint following surgical repair of ligament injuries and after ligament replacement plasty].

Characteristic radiological findings following operative repair of the ligaments of the knee joint are described and related to the type of operative procedure. The operations depend on a number of basic principles which are discussed in detail. The majority of these surgical procedures are not apparent radiographically. It is only by having a knowledge of the individual procedures and of the resulting functional changes in the knee joint, that the informed radiologist can make a correct assessment of the post-operative radiographs. Defects resulting from bone drilling can be recognised tomographically in the early postoperative phase, or if they persist for any reason. This could be confirmed by experiments on pigs' knees.

Adolescent↗
PubMed1988

Latent hepatitis B virus infection with full-length viral genome in a patient serologically immune to hepatitis B virus infection.

The presence, state, physical structure and cellular localization of hepatitis B virus (HBV) DNA were investigated in a patient with hepatitis B surface antigen (HBsAg)-negative chronic liver disease. HBV serology was positive for antibodies to hepatitis B core antigen (anti-HBc), to hepatitis B e antigen (anti-HBe) and to HBsAg (anti-HBs); no HBV DNA was detectable in serum. Southern blot analyses of DNA extracted from the liver demonstrated free monomeric HBV DNA as two distinct species: a predominant species of fully double-stranded relaxed circular molecules and a minor species of linear molecules of 3.2 kilobase pairs (kbp) length. Restriction enzyme analyses identified the HBV genome as HBsAg subtype adw2. Cell fractionation studies further revealed that the free viral DNA species were localized exclusively in liver cell nuclei. These findings in a patient serologically immune to HBV infection demonstrate that in hepatocytes HBV can establish a latent infection, characterized by the extrachromosomal presence of a full-length viral genome without production of infectious virus or synthesis of viral antigens.

Aged↗
PubMed1988

[Treatment of the open tibial fracture with the fixateur externe with special reference to osteosynthesis of the fibula].

In the treatment of open fractures of the lower limb and of fractures combined with severe damage of soft tissues, external fixation is favoured. Additional soft tissue damages in the compartments of the lower limb are avoided by using an external fixation in form of a clamp. In defect fractures, shattered fractures and in all fractures in the distal third the stability of clamp fixation is enhanced by plating of the fibula. Furthermore by osteosynthesis the reconstruction of the correct length of the lower limb can be performed. 36 fractures healed definitively in an average of 17.1 weeks by this procedure. Secondary procedures were: 8 cases with decompression of compartments, 11 cancellous bone grafts, 13 fixateur externes were removed because of the infection of the Schanz'screws, and healing was achieved by using a plaster cast. The therapeutical procedure was changed in 5 patients to a plate osteosynthesis and in 8 patients to an intramedullary nail.

Adolescent↗
PubMed1988

[Indications for operation in elbow dislocation].

This paper briefly presents the anatomy of the elbow joint, its pathophysiology, the various types of dislocation of the elbow joint and concomitant injuries, the appropriate diagnostic procedures and the indications for surgery and the operative technique applied for correction of dislocation. The only urgent indications for operative treatment are elbow joint dislocation with concomitant bone injuries, persistent instability or luxation position, open injuries and vessel and/or nerve injuries. For purely ligamentous lesions combined with relative loss of stability an operative procedure does not seem necessary. The operative technique applied for the treatment of habitual or recurrent dislocation is also described.

Humans↗
PubMed1987

Hepatocellular carcinoma and hepatitis B virus infection: molecular evidence for monoclonal origin and expansion of malignantly transformed hepatocytes.

The clonality of tumor cells was studied in a patient with metastasizing hepatocellular carcinoma (HCC). Using hepatitis B virus (HBV) DNA as a genetic marker, the pattern of integration of viral DNA into the tumor cell genome was determined by Southern blot analyses of DNAs extracted from different HCC lesions in the liver and both lungs. All tumor tissues examined were found to have viral DNA integrated into the same site(s) of the cellular genome. This finding provides direct molecular evidence for a monoclonal origin and expansion of malignantly transformed hepatocytes during tumor growth and metastasis. This characteristic is similar to other human cancers associated with viral infections, such as adult T-cell leukemia, Burkitt's lymphoma, or cervical cancer, and is important for our understanding of viral oncogenesis in man.

Aged↗
PubMed1987

Structural identifiability of "first-pass" models.

This paper considers the structural identifiability of two compartmental models classically used to describe the pharmacokinetics of drugs orally administered and transformed into a metabolite with a first-pass effect at the hepatic level. The simplest model proves not to be globally identifiable even when plasma and urinary measurements of the drug and metabolite concentrations are made. It admits two sets of admissible solutions, so that a priori knowledge must be introduced to distinguish them. The more complex model appears globally identifiable when blood and urine measurements are made.

Humans↗
PubMed1987

OMNE: a new robust membership-set estimator for the parameters of nonlinear models.

A new method for estimating parameters and their uncertainty is presented. Data are assumed to be corrupted by a noise whose statistical properties are unknown but for which bounds are available at each sampling time. The method estimates the set of all parameter vectors consistent with this hypothesis. Its results are compared with those of the weighted least squares, extended least squares, and biweight robust regression approaches on two data sets, one of which includes 33% outliers. On the basis of these preliminary results, the new method appears to have attractive properties of reliability and robustness.

Kinetics↗