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Biomedical subjects

R Steffen

Publications and source records attributed to R Steffen.

At least 181 records · Page 10Linked to original sources
PubMed1991

[Protection of the anastomosis by a special drainage procedure in the Kausch-Whipple operation].

The pancreaticojejunostomy after duodenopancreatectomy is the "achilles heel" of the procedure. We describe herein a technique for percutaneous drainage of the efferent limb of the Roux-en-Y loop relieving tension from the anastomosis. 66 Whipple procedures have been carried out using this technique. Operative mortality was 1.5% and anastomotic leakage occurred in 2 cases (3%). In addition one patient had to be reoperated for biliary fistula. Our technique for intraluminal loop drainage is a safe and reliable method for protection of the pancreaticojejunostomy.

Adult↗
PubMed1991

[Primary prevention of HIV infection].

Primary prophylaxis by a change of behaviour in the population continues to be the only effective possibility to prevent a further spread of the aids epidemic. The most important presupposition for this is the precise knowledge of the ways of transmission and the corresponding protective measures. Informations referring to this must turn up repeatedly and above all free of contradictions at all levels of the preventive campaign. The desired changes of behaviour suppose also a climate of confidence and solidarity. The physician's task of prevention is part of the comprehensive strategy of HIV-prevention in Switzerland (effect in width and depth on population- and target groups and on the individual level). It is naturally the physician's domain to look after and counsel individually. Most variable possibilities of beginning a conversation about Aids prevention offer themselves to him. He should put the indication for this as generous as possible and deal extensively with a possible risky behaviour which might not be conscious to both the patient and the physician. The HIV antibody test is indicated in certain situations, however the pre- and posttest counselling is in any case much more decisive than the result of the test. The preventive measures recommended up to now for the most important ways of transmission (sexual contact, intravenous drug use, perinatal transmission, blood/blood products) are still valid without modification.

HIV Infections↗
PubMed1991

[Technique of microvascular jejunum transfer for replacement of the cervical esophagus].

Technique and results of the first 10 free jejunal grafts after pharyngolaryngectomy are presented. End-to-side venous anastomosis and end-to-side pharyngojejunostomy instead of end-to-end techniques are proposed. Hospital mortality was 0 and as minor complications 1 uncomplicated fistula of the proximal and 1 stenosis of the distal anastomosis along with 1 wound infection were seen. There were no vascular complications and no graft loss. All patients were able to swallow and to eat thus an excellent quality of life was achieved.

Adult↗
PubMed1991

[Systematic indications of various free transfer flaps in the area of the head and neck].

Many microsurgical free flaps have been described to tackle various problems in the head and neck. The authors present a system of indications which has proved to be suitable as judged by the functional and cosmetic results obtained. The harvesting of these flaps requires versatile training in surgical techniques for the different anatomical areas. This system of indications comprises the free fasciocutaneous forearm flap, jejunal loops, the fasciocutaneous parascapular flap, iliac crest flaps with vascularized bone and the parascapular cutaneous, latissimus dorsi osteomyocutaneous double flap.

Bone Transplantation↗
PubMed1990

[Malaria prophylaxis of West German travelers to Africa].

From May 1985 to July 1988, 11,445 German residents who had travelled to Africa filled in a questionnaire during the return flight and a second questionnaire sent to them 3 months later. 92.6% of the travellers had been on holiday and 99.3% of these holiday-makers were aware of the risk of malaria. Before and during their stay in the tropics 10,955 travellers (95.7%) had taken the chemoprophylaxis correctly, though in some instances the drugs prescribed were not in accordance with the guidelines existing at the time. However, 3227 of them (35.5%) discontinued the drugs too early, i.e. less than four weeks after their return. Only 4.3% of the travellers had taken proper precautions against mosquito bites. In view of the ever increasing numbers of people travelling to countries where malaria is endemic, doctors and travelers should be provided with more information and should be given more consistent advice on malaria prophylaxis.

Africa, Western↗
PubMed1990

Comparison of University of Wisconsin (UW) and Eurocollins (EC) preservation solutions in a rat liver transplant model.

The Eurocollins (EC) and University of Wisconsin (UW) preservation solutions were compared in a rat liver transplant model. After hepatectomy, 48 rat livers were flushed with either EC or UW preservation solution and were randomly assigned to 1, 12, 24, and 30 h of preservation at 4 degrees C, resulting in eight groups each containing six livers. Following preservation, orthotopic liver transplantation with reconstruction of the hepatic artery was performed. The efficacy of the preservation solution was assessed at 48 h post-transplantation by survival histological features and aspartate transaminase assay (AST) values. None of the rats survived 30 h of liver preservation with EC whereas five out of six rats did with UW preservation. After 24 h of liver preservation, three of the six rats in the EC group survived, compared to all six rats in the UW group. Histological evidence of severe ischemia was found in both groups in all but one survivor (UW, 24 h). After 12 h of EC preservation, one rat died within 48 h and severe ischemic changes were found in the remaining five rats. Among the rats with 12 h of UW preservation, only two out of six showed ischemic changes, and all six rats survived beyond 48 h. Without preservation (1 h), ischemic damage was found in two out of six rats in each group and all rats survived. The median AST values were higher in the EC groups than in the UW groups; the difference became significant after 12-h preservation (EC 900 IU/l versus UW 465 IU/l) and 24-h preservation (EC 5220 IU/l versus UW 631 IU/l).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1990

[Cost-benefit analysis of malaria prophylaxis with mefloquine in travelers to Kenya].

With an increasing movement towards cost saving in the health sector, preventive medicine must also be judged according to its economic viability. The fact that prevention can autofinance itself is suggested by the results of a cost/benefit analysis of chemoprophylaxis of Falciparum malaria with Mefloquin among travellers in Kenya. Out of the whole group of travellers analysed by means of an interview-based test (Malpro-Study), the costs in the case of both Switzerland and the Federal German Republic were lower for those people who had undergone Mefloquin-prophylaxis than for those who had not. In this way the prophylaxis not only compensates the required outlay but also results in an overall benefit in macroeconomic terms. Therefore economically based opposition to the prophylaxis of malaria with Mefloquin for short stays in high-risk countries is not justified.

Animals↗
PubMed1990

Risks of hepatitis B for travellers.

Retrospective and follow-up studies in travellers visiting developing countries suggest that 1 in 2500 develops symptomatic hepatitis B virus (HBV) infection after returning home. Vacationers are rarely affected. In contrast, persons working in developing countries frequently seroconvert. Hepatitis B vaccination is therefore indicated for all persons residing for a prolonged period of time in developing countries, particularly medical personnel, missionaries, or others having close contact with the autochthonous population. This immunization is usually unnecessary for vacationers, unless they intend to break basic rules of hygiene.

Follow-Up Studies↗
PubMed1990

[Unilateral reconstruction of the anterior neck using a combination flap technique].

This technique is recommended for the one-stage reconstruction of the cervical esophagus, for the protection of the cervical vessels by soft tissues and for the substitute of the anterior neck skin. The microvascular free jejunal flap is transplanted and then covered by the myocutaneous pectoralis-major-island-flap. Indications are complete defects of the anterior neck after the resection of tumors, after the resection of necrotic tissues following radionecrosis, when all soft tissues in front of the prevertebral fascia have to be resected. Details of the surgical technique are explained. This combination flap technique proved to be useful in 4 patients without any complications.

Aged↗
PubMed1990

[Dynamic CT and angio-CT following liver transplantation].

This is a prospective study of the value of dynamic CT with a rapid scan frequency for the control of liver transplants. In 28 patients dynamic CT was performed with table movement and angio-CT without table movement, using a standard contrast bolus. In 97% of cases the central portions of the portal and hepatic veins could be delineated. The peripheral vessels were better demonstrated by angio-CT (79%) than by dynamic studies with table movement (47%). Parenchymal lesions, such as infarcts, and changes round the liver, such as lymphoedema or haematomas, were adequately demonstrated by either method. In addition, angio-CT provided information on abnormalities of perfusion within the transplant.

Adult↗
PubMed1990

[Magnetic resonance tomography in orthotopic liver transplantation].

14 patients with orthotopic liver transplantation were prospectively studied with MR imaging. MR imaging demonstrated a perivascular collar surrounding central portal venous branches in 14 patients. The perivascular collar had low signal intensity on T1-weighted and high signal intensity on T2-weighted images. In 10 of the 14 patients, a perivascular collar was also observed around peripheral portal venous branches. The perivascular collar is probably caused by intraoperative interruption of hepatic lymph vessels and resultant impaired lymph drainage. It is a normal postoperative phenomenon in hepatic transplants. MR imaging is particularly useful in the distinction of postoperative hematoma from other intra- and extrahepatic fluid collections and may provide a noninvasive assessment of liver transplant rejection.

Adult↗
PubMed1990

Immunosuppressive function of hepatitis B antigens in vitro: role of endoribonuclease V as one potential trans inactivator for cytokines in macrophages and human hepatoma cells.

The mRNAs of transiently expressed cytokine genes contain AUUUA-rich sequences in the 3' untranslated regions. In order to examine whether the AU-specific endoribonuclease V (EC 3.1.27.8) described previously by us transinactivates those mRNA species, we introduced a 51-nucleotide ATTTA sequence from tumor necrosis factor into the 3' untranslated region of beta-globin gene. Transcripts of that construct, synthesized in vitro, were prone to endoribonuclease V digestion at those AU-rich sequences. Stimulation of human macrophages with lipopolysaccharide resulted in a shift of the association state of the enzyme from the nuclear matrix-associated to the free form. This shift was strongly prevented by the hepatitis B surface antigen (HBsAg) and more weakly by hepatitis B nucleocapsid antigen and hepatitis B antigen of the X region. HBsAg and, to a lesser extent, hepatitis B nucleocapsid antigen and hepatitis B antigen of the X region inhibited the release of alpha interferon, tumor necrosis factor alpha, and granulocyte-macrophage colony stimulating factor, while it had no effect on interleukin-1 production from stimulated macrophages. Using the human hepatoma cell line PLC/PRF/5, we provide further experimental evidence that endoribonuclease V acts in trans as a posttranscriptional inactivator for nuclear matrix-associated cytokine transcripts. These results suggest that those cytokine transcripts which contain reiterated (overlapping) AUUUA sequences are degraded by nuclear matrix-associated endoribonuclease V. This degradation was comparably high in cells incubated with HBsAg or cells which produced this antigen.

Animals↗
PubMed1990

Malaria prophylaxis and self-therapy in airline crews.

The risk of malaria infection in airline crews is estimated to be 0.5 per 1,000 persons per night in areas with high levels of malaria transmission. Routine chemoprophylaxis for years is not recommended because of possible side effects. Airline crews should therefore use appropriate measures to prevent mosquito bites. In addition, they may need to carry "standby" medication with them to be used for presumptive treatment of a febrile illness if medical attention is not readily available.

Aerospace Medicine↗