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Biomedical subjects

R Steffen

Publications and source records attributed to R Steffen.

At least 145 records · Page 8Linked to original sources
PubMed1993

Tetanus in Switzerland 1980-1989.

Tetanus cases that occurred in Switzerland between 1980 and 1989 have been reviewed with the help of three data surveillance systems: a) morbidity data from the Federal Office of Public Health (FOPH), b) mortality data from the Swiss Federal Statistical Office (SFSO), and c) data from the Association of Swiss Hospitals and Clinics (VESKA), completed by a written enquiry to clinics which did not (or only partly) participate in the VESKA system during the study period. For every case, a questionnaire was sent to the clinic to verify the diagnosis and to obtain additional information on the circumstances of occurrence. Ninety-one cases were identified. This corresponds to a yearly incidence of 1.93 per million population between 1980-84 and 0.88 for the 1985-89 period (p < 0.01). Eighty-one percent of the cases were older than 50 years of age and women were significantly more frequently affected than men. None of the cases identified had a documented primary immunization series. Data available at the FOPH and SFSO level have been compared to data obtained through the VESKA system using the Chandra Sekhar and Deming method. It is estimated that 134 tetanus cases (95% CI: 91-197) have occurred in Switzerland between 1980 and 1989, together with 28 deaths (95% CI: 27-31). Based on these estimates, FOPH appears to detect only 6-13% of tetanus cases occurring in Switzerland. By contrast, SFSO had fairly consistent data for 81-100% of tetanus associated deaths. The low rate of tetanus reported by physicians necessitates a sustained effort to increase the understanding of epidemiological surveillance by Swiss practitioners.

Adolescent↗
PubMed1993

Prevalence of hepatitis A antibodies in Swiss travellers.

To assess the prevalence of antibodies to hepatitis A virus (anti-HAV) in future travellers, all visitors to the Zurich University Vaccination Center in July/August 1990 were invited to participate in a cross-sectional study. A total of 1126 future travellers were recruited to have a blood sample drawn and to complete a brief questionnaire. Among these, 35 refused or were excluded, thus 1091 were evaluated. The overall prevalence of anti-HAV was 16.5%. This rate was 5.9% in future travellers born in or after 1961, 11.8% in those born 1951-60, 21.4% in those born 1941-50 and exceeded 49% in all decades born in or before 1940. Risk factors for significantly elevated anti-HAV rates were place of birth or a stay exceeding one year in tropical, subtropical or Southern European countries and travel for occupational reasons. Compared with findings from earlier surveys conducted mainly among blood donors in Switzerland and elsewhere in Europe, the results of the present study show lower anti-HAV prevalence rates. In conclusion, it seems unnecessary to test future travellers for anti-HAV except if they are born before 1944, or have a history of jaundice or of prolonged stay in the tropics, subtropics or in Southern Europe.

Adolescent↗
PubMed1993

Hepatitis A and hepatitis B: risks compared with other vaccine preventable diseases and immunization recommendations.

The incidence rate of hepatitis A is 3(-6)/1000 per month of stay in a developing country in unprotected travellers. Tramps and other persons feeding themselves under bad hygienic conditions have a rate of 20/1000. In many industrialized countries, persons below the age of 50 years have a seroprevalence rate of anti-HAV < 20%. Hepatitis A morbidity and mortality rates in travellers are far greater than those of any other vaccine-preventable infection in travellers, with the exception that hepatitis B shows a slightly greater mortality rate in expatriates. Future studies will determine the role of hepatitis C and E. Typhoid fever shows an incidence rate of 0.3/1000 in foreigners on the Indian subcontinent, and in many parts of North and West Africa, excluding Tunisia; in other parts of the Third World it is tenfold lower. In poliomyelitis, tetanus, diphtheria, cholera, rabies and Japanese encephalitis the incidence rate is < or = 0.002/1000.

Developing Countries↗
PubMed1993

Treatment of travellers' diarrhoea with fleroxacin: a case study.

A double-blind, randomized, placebo-controlled trial was conducted to evaluate the efficacy and safety of fleroxacin for one or two days as treatment for patients with travellers' diarrhoea. A total of 195 patients who were suffering with acute diarrhoea of less than six days' duration were enrolled. One hundred and fifty-one patients, of whom 49 received placebo, 54 received fleroxacin 400 mg for one day and 48 received fleroxacin 400 mg for two days, were included in the analysis of efficacy. The results showed that fleroxacin was significantly superior to placebo, but that there was no significant difference in terms of efficacy between the one- and two-day regimens. Adverse events, particularly minor neuropsychiatric disturbances such as headache and insomnia, were significantly more common amongst patients receiving active treatment. In conclusion, a single dose of fleroxacin 400 mg could be recommended as self-treatment for visitors to high-risk countries who develop travellers' diarrhoea.

Adult↗
PubMed1993

Comparison of quadruple immunosuppression after liver transplantation with ATG or IL-2 receptor antibody.

Treatment with monoclonal IL-2 receptor antibodies has been successfully used for immunosuppressive induction therapy following organ transplantation in the recent past. The present study was conducted to compare for the first time a cyclosporine-based quadruple immunosuppressive regimen including a monoclonal IL-2 receptor antibody or ATG as induction therapy after orthotopic liver transplantation. In two groups of 33 patients each, postoperative survival, graft biopsies, liver function enzymes, and the clinical courses after OLT were evaluated. Our results indicate that monoclonal IL-2 receptor antibody therapy as part of a quadruple immunosuppressive regimen is better tolerated and is at least as effective as ATG in prevention of allograft rejection following OLT. Furthermore, our data indicate that a slightly better liver function in general and a lower incidence of rejection reactions necessitating treatment could be observed in the group of patients treated with the monoclonal IL-2 receptor antibody. This study provides evidence that monoclonal IL-2 receptor antibody therapy may be a useful tool for the immunosuppressive induction therapy following clinical orthotopic liver transplantation.

Adult↗
PubMed1993

[Fixateur interne: a comparative biomechanical study of various systems].

The three-dimensional stability provided by three spinal fixation devices of the type "fixateur interne" have been studied in an in vitro model using L2-L4 sections of the lumbar spine. Three-dimensional rotations and translations for the intact and instrumented spine under physiological loads in flexion/extension, lateral bending, and axial rotation were determined. To objectify the results, a dimensionless related stability parameter was introduced. The tested devices were: Dick (AO-Synthes), Kluger (Endotec), and SOCON (Aesculap). In addition a vertebrectomy L3 was performed to simulate a severe fracture model. Different screw diameters allowed for a direct comparison of two internal fixateur systems on identical specimens. In contrast to the intact spine, the instrumented spine reflects purely linear structural behaviour with a stabilization significant in flexion/extension and lateral bending and only moderate in axial rotation. Differences for various systems tested were found to be small. The results for the fracture model confirmed the efficiency of these internal fixation devices.

Biomechanical Phenomena↗
PubMed1993

[Effect of soft tissue injuries on the biomechanics of sagittally symmetric thoracolumbar vertebral compression fractures].

Thoracolumbar compression-fractures were performed in an in-vitro model with a deformity of 9.7 degrees and 12.3 degrees. After stabilisation of the fracture additional soft tissue injuries were carried out by dissection of the posterior ligaments and ruptures of the nucleus and annulus of the intervertebral disc. The disc injuries led to a significant instability. The degree of kyphotic deformation showed the most distinct influence on torsion with an increase in range of motion of 64% (9.7 degrees) versus 181% (12.3 degrees).

Biomechanical Phenomena↗
PubMed1992

[Liver transplantation in erythrohepatic protoporphyria].

A 51-year-old man had for 5 years been known to have erythropoietic protoporphyria. GPT levels were raised up to 40 U/l, gamma-GT up to 120 U/l. After lengthy exposure to sun radiation an erythema with blisters, abdominal discomfort and jaundice developed (total bilirubin 7.3 mg/dl) and biliary liver cirrhosis with portal hypertension and splenomegaly were diagnosed. Because the acute hepatobiliary complications were not improved by conservative treatment (daily 750 mg ursodeoxycholic acid and 12 g colestyramine), an orthotopic liver transplantation was performed without complication. The excised liver showed small nodular parenchymal transformation and contained reddish brown protoporphyrin pigment in the hepatocellular cytoplasm, the Kupffer cells, the canaliculi and in some biliary ducts. Bilirubin and transaminase levels in blood became normal after the transplantation, as did the urinary excretion of coproporphyrin. However, isomer I was still dominant. The protoporphyrin level in erythrocytes and plasma remained elevated. After a symptom-free interval of one year biochemical and histological tests demonstrated protoporphyrin-induced damage in the transplanted liver.

Cholestyramine Resin↗
PubMed1992

Inhibition of hepatitis B virus production by modified 2',3'-dideoxy-thymidine and 2',3'-dideoxy-5-methylcytidine derivatives. In vitro and in vivo studies.

The effect of analogues of both 2',3'-dideoxy-3'-fluorothymidine (FddThd) [2',3'-dideoxy-3'-fluorouridine (FddUrd), 2',3'-dideoxy-3'-fluoro-5-chlorouridine (FddClUrd), 2',3'-dideoxy-3'- fluoro-5-bromouridine (FddBrUrd) and 2',3'-dideoxy-3'-fluoro-5-bromovinyluridine (FddBVUrd)] and 2',3'-dideoxy-3'-fluorocytidine (FddCyt) [2',3'-dideoxy-3'-fluoro-5-fluorocytidine (FddFCyt), 2',3'-dideoxy-3'-fluoro-5-chlorocytidine (FddClCyt), 2',3'-dideoxy-3'-fluoro-5-methylcytidine (FddMeCyt), 2',3'-dideoxy-3'-fluoro-5-ethylcytidine (FddEtCyt), 2',3'-dideoxy-3'-chloro-5-methylcytidine (ClddMeCyt), 2',3'-dideoxy-3'-amino-5-methylcytidine (AmddMeCyt), 2',3'-dideoxy-3'-azido-5- methylcytidine (AzddMeCyt) and arabinosyl-5-methylcytosine (AraMeCyt)] were tested for their potential antiviral activity in vitro using the human hepatoblastoma cell line, Hep G2 2.2.15, which was transfected with a vector containing hepatitis B virus (HBV). It was found that FddThd, FddMeCyt, FddEtCyt, ClddMeCyt, AmddMeCyt and AraMeCyt display cytostatic activity at concentrations (CD50 values) between 0.54 (FddMeCyt) and 3.93 microM (FddEtCyt), while FddUrd, FddClUrd, FddBrUrd, FddBVUrd, FddCyt, FddFCyt, FddClCyt and AzddMeCyt do not affect cell growth at concentrations of up to 25 microM. Among the thymidine analogues tested, FddThd is the most effective antiviral agent: at a concentration of 0.03 microM a more than 90% reduction of HBV DNA synthesis was measured. On the other hand, the antiviral indexes displayed by FddClUrd, FddBrUrd and FddBVUrd are higher than tht of FddThd; FddUrd was completely inactive. The most powerful antiviral agents in the group of cytidine analogues tested in vitro were FddMeCyt (more than 90% reduction of HBVDNA synthesis at 0.10 microM) and ClddMeCyt (0.10 microM); FddClCyt, FddEtCyt, AmddMeCyt and AraMeCyt were of intermediate activity. None of the negligible antiviral activity was determined for FddUrd, FddCyt, FddFCyt and AzddMeCyt. FddThd and FddMeCyt displayed in vivo an antiviral effect in the duck/duck HBV (DHBV) animal system. Administration of 10 or 20 mg/kg (total daily dose) of FddThd and 5 or 10 mg/kg of FddMeCyt (i.m. daily) to ducks infected with DHBV for 12 days blocked virus production. Termination of treatment with FddThd of infected animals led to reappearance of the virus in the serum though at lower levels. The in vitro and the in vivo data suggest that FddThd and FddMeCyt might be promising antiviral agents for the treatment of infection caused by HBV in humans.

Animals↗
PubMed1992

Hepatitis C virus reinfection in allografts after orthotopic liver transplantation.

From September 1988 to May 1991, 160 orthotopic liver transplantations were performed in our hospital. Twenty-four patients had end-stage cirrhosis caused by chronic non-A, non-B hepatitis. Antibodies against hepatitis C virus were documented before and after orthotopic liver transplantation in 13 patients. Studies using the polymerase chain reaction demonstrated hepatitis C virus RNA in the serum and liver tissue of 17 patients (10 of whom tested positive for hepatitis C virus antibodies) before orthotopic liver transplantation. Tissue samples taken from liver grafts during the operation were hepatitis C virus RNA negative in every case. Ten of these 17 patients had positive hepatitis C virus RNA findings in serum and liver biopsy specimens within the first month after surgery. One patient died of Mucor sepsis 2 mo after orthotopic liver transplantation. Another patient died of multi-organ failure 3 mo after a retransplantation. Two patients underwent retransplantation for graft rejection at 2 and 3 mo, respectively. One year after orthotopic liver transplantation, hepatitis C virus RNA was demonstrated in allograft biopsy specimens in 13 of 15 patients. Two patients remained hepatitis C virus RNA negative in repeated biopsies up to 12 mo. Mild portal and lobular hepatitis developed within 6 months of orthotopic liver transplantation in four patients and within 1 yr in five additional patients. The data suggest that persistent hepatitis C virus reinfects the allograft in most cases, but the risk of acute organ damage caused by hepatitis C virus reinfection is low.

Adult↗
PubMed1992

Multivisceral cluster transplantation in the rat.

Transplantation of multivisceral grafts has evolved recently as a new therapeutic modality for hepatopancreatobiliary malignancies. The mutual interactions between the liver, pancreas, small bowel and the recipient organism after cluster grafting are not clearly understood and deserve further experimental evaluation. We present a technique for combined hepatopancreaticoduodenal cluster transplantation in the rat. The cluster grafts consisted of a pancreaticoduodenal graft and an orthotopic arterialized liver graft. A separate arterial anastomosis of the liver and a bile duct anastomosis were not necessary. Bile and exocrine pancreas secretions drained over the duodenal conduit of the graft into the recipients jejunum via an end-to-side anastomosis.

Animals↗
PubMed1992

Protection by pentoxifylline against graft failure from storage injury after orthotopic rat liver transplantation with arterialization.

Destruction of the endothelial cell lining and activation of Kupffer cells after reperfusion limits the safe storage of livers for transplantation surgery. Tumor necrosis factor-alpha (TNF) release by activated Kupffer cells may contribute to graft failure from storage injury. Accordingly, we evaluated whether pentoxifylline, which suppresses macrophage TNF release, would improve graft survival after orthotopic rat liver transplantation with arterialization. Livers from syngeneic Lewis rats were stored for 12-24 h in cold UW solution. Prior to implantation, the livers were flushed with cold Ringer's solution or warm Carolina rinse solution B. With either rinse, pentoxifylline treatment of graft recipients significantly improved graft survival. Combined use of pentoxifylline (50 mg/kg for 5 days) and Carolina rinse solution doubled the safe storage time to 24 h. Acidotic pH and antioxidants were essential components of Carolina rinse solution that acted synergistically with pentoxifylline. Pentoxifylline was also shown to suppress TNF release by lipopolysaccharide (LPS)-stimulated cultured rat Kupffer cells. Thus, pentoxifylline may protect against primary non-function and failure of grafts from storage injury by suppressing excessive TNF release by activated Kupffer cells. However, neutralization of TNF with excess anti-TNF antibody did not improve survival. This may mean that depletion of TNF is as deleterious as excess TNF production. Alternatively, other Kupffer cell secretions [e.g., interleukin-1 (IL-1), interleukin-6 (IL-6) and other cytokines] may be involved in the pathogenesis of graft failure. In conclusion, pentoxifylline could protect against graft failure from storage injury.

Animals↗
PubMed1992

Quadruple immunosuppression including a new IL-2-receptor antibody and the incidence of infections after liver transplantation.

Immunosuppression is a primary concern after orthotopic liver transplantation (OLT). On the one hand, the graft is at jeopardy through acute or chronic rejection, and on the other, immunosuppression and antirejection therapy increase the risk of infectious complications. Effective immunosuppression therefore should prevent rejections without leading to a high rate of infections, bearing in mind the fact that infections and infection-related complications are the most frequent causes of early death after liver transplantation. With more specific immunosuppression the infectious complications can potentially be minimized. Antithymocyte globulin (ATG) and the first monoclonal antibody OKT3 immunosuppression are non-specific. The replacement of these antibodies in a quadruple immunosuppressive regimen with the new monoclonal IL-2R antibody BT 563 probably reduces the early infection rate. We report on our first experience with BT 563. The incidence of infection was compared with a historical control group with ATG.

Adult↗