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Biomedical subjects

P Michielsen

Publications and source records attributed to P Michielsen.

At least 55 records · Page 3Linked to original sources
PubMed1990

Growing bone cysts in long-term hemodialysis.

All patients with chronic renal failure undergoing hemodialysis for more than 10 years in the university hospitals of Leuven were selected for this study. The medical records and radiographs of these 21 patients were studied retrospectively. Skeletal surveys were examined for the presence and location of subchondral cysts. The predialysis films and the films taken after 5, 10, 15 and 20 years of dialysis were reviewed. Subchondral cysts that grew in size and number were found in the wrist, humeral head, hip, and patella. Accurate measurements were made of cysts in the wrist and compared with a control group. In the dialysis group, cystic involvement of the wrist was more common and the size and number of the cysts were larger. Soft tissue swelling was seen in the dialysis group but not in controls. Soft tissue swelling was assessed on shoulder radiographs by measuring the acromiohumeral distance (ACD) and in the knees by ultrasonic measurement of synovial thickness. In 11 patients synovial or bone biopsies or aspirated synovial fluid were available. All these patients had swollen joints and multiple subchondral periarticular cysts. Amyloid deposition was found in ten of these patients, and this proved to be composed of B2 microglobulins in seven.

Amyloidosis↗
PubMed1990

Azathioprine hypersensitivity in a renal transplant recipient.

Hypersensitive reactions to azathioprine have been reported infrequently, and always in nontransplanted patients. Here, a renal transplant recipient with a severe hypersensitive reaction to azathioprine is described. We suggest that, until recently, hypersensitivity to azathioprine was suppressed in transplant recipients by the association of high doses of corticosteroids. Since the introduction of cyclosporin, azathioprine therapy is usually associated with corticosteroids in a much lower dose, so an increasing occurrence of azathioprine hypersensitivity in transplanted patients might be expected.

Adult↗
PubMed1990

Induction of mixed lymphocyte reaction nonresponsiveness after chimeric thymus transplantation.

Discussion still continues regarding whether self-tolerance is imparted within the thymus by the thymic epithelial cells (TEC) or by the bone marrow-derived (BMD) dendritic cells and macrophages. Many experiments suggest that BMD cells may be the major cells responsible for inducing tolerance within the thymus. In order to address this question and to see whether thymus chimerism could play a role in establishing transplantation tolerance, we looked in the present experiments at the induction of in vitro tolerance after transplantation of chimeric thymuses. Chimeric thymuses were constructed by injecting T-depleted C3H (H2k) bone marrow into lethally irradiated BALB/c (H2d) mice and were thus composed of TEC of BALB/c and BMD cells of C3H origin, something which was verified with immunoperoxidase staining. Subsequently, chimeric thymuses were transplanted into thymectomized BALB/c mice that were lethally irradiated and reconstituted with T-depleted syngeneic BALB/c bone marrow. In 8 out of 11 BALB/c mice this procedure was successful, and in all chimeric thymus graft-bearing mice, specific tolerance for C3H (H2k) antigens was documented in the mixed lymphocyte reaction (MLR). These experiments thus show that: (1) immunological tolerance can be imparted by BMD cells in the thymus and (2) the presence of chimerism within the thymus could be one of the mechanisms involved in the establishment or maintenance of transplantation tolerance.

Animals↗
PubMed1990

Efficacy of interferon alfa-2b with or without prednisone withdrawal in the treatment of chronic viral hepatitis B. A prospective double-blind Belgian-Dutch study.

A prospective, double-blind study was carried out to assess the efficacy of interferon alfa-2b, with or without pre-treatment prednisone withdrawal, in patients with chronic hepatitis B. A total of 57 Belgian and Dutch patients were included in the study. Patients were divided into four treatment groups: Group A, prednisone withdrawal followed by interferon 5 million units per day; Groups B and C, placebo followed by interferon 5 or 1 million units, respectively; and Group D, untreated controls followed for 1 year. All treated patients received interferon for 16 weeks. Two of the 14 control patients lost hepatitis B e antigen during the year of study, and only one of 15 patients in the interferon 1 million units group. Among the 28 patients receiving 5 million units of interferon (with or without prednisone withdrawal), ten (36%) cleared hepatitis B e antigen during the study or within 6 months of the end of therapy. This was associated with a marked improvement in serum transaminase levels. When comparing Groups A and B, it was found that prednisone withdrawal therapy enhanced the response to interferon in patients with pre-treatment serum alanine aminotransferase levels below 100 IU/l, bringing the seroconversion rate up to 50%, compared to 17% on interferon alone. This effect was not seen in patients with high pre-treatment transaminase levels. All treatment responders showed a marked improvement in Knodell index score, whereas in the 15 non-responders from groups A and B, overall inflammatory activity remained the same in six, improved in five and worsened in four.(ABSTRACT TRUNCATED AT 250 WORDS)

Belgium↗
PubMed1990

Criteria for selecting organ donors and recipients.

As there is a world-wide shortage of organs for transplantation, the selection of the patients is more defined by the availability of transplantable organs than by the medical condition of the potential recipient. This shortage of cadaveric organs is mainly responsible for the use of living donors. With HLA identical sibling donors the results are better than with cadaveric organs, but the ethical problems are usually underestimated. For the parent-to-child donation, the HLA compatibility is less than what could be achieved with well-matched cadaveric donors. The use of genetically unrelated donors is unacceptable from the ethical as well as from the medical point of view. The short- and long-term risk of donation has been insufficiently documented. The experience with the introduction of an opting-out legislation in Belgium in 1987 demonstrates that the shortage of cadaveric organs can be overcome. Harmonization of the legislation is, however, necessary so as to achieve comparable organ retrieval rates between countries participating in organ-exchange organisations.

Cadaver↗
PubMed1989

Listeria monocytogenes meningitis.

The history and findings of all patients with Listeria meningitis admitted to the University Hospital of Leuven from 1967 to 1987 were reviewed. Listeriosis during pregnancy or the perinatal natal period was not considered. Predisposing conditions in these 23 patients included renal transplants (9), immunosuppressive therapy (2), diseases of the lympthoreticular system (3) and chronic alcoholism (1). One man had an inversed T4/T8 ratio. In 7 patients no underlying disorder was detected. Disease onset may be acute or subacute. There are no clinical features distinguishing Listeria meningitis from other acute bacterial meningitides. The number of leukocytes in the CSF varied from 3 to 3700, most often with a predominance of mononuclear cells. A decrease of the glucose level in the CSF was not always present. The initial gram stain was often unrevealing and it took up to 4 days for CSF cultures to become positive. Blood cultures were often important for the identification of the organism.

Adolescent↗
PubMed1989

Postendoscopic sphincterotomy stenosis.

We report on two patients. The first patient is a 62-year-old female patient who had cholecystectomy in 1970, and in whom two small bile duct stones were removed after endoscopic sphincterotomy in 1987. Within two months of this procedure, she developed three episodes of documented acute pancreatitis. The other patient, a 58-year-old female, developed acute pancreatitis three months after an endoscopic sphincterotomy for stones in the common bile duct. In both patients, ERCP revealed a cicatricial stenosis of the common bile duct and the pancreatic duct. The condition was resolved by repeat sphincterotomy. The first patient needed repeated endoscopic insertion of bilioduodenal endoprostheses and an endoprosthesis in the pancreatic duct. It is interesting to note that, in contrast to surgical reports, very few postpapillotomy stenoses are reported by endoscopists.

Common Bile Duct Diseases↗
PubMed1989

Efficacy and tolerance of treatment with recombinant-human erythropoietin in chronic renal failure (pre-dialysis) patients.

Recombinant-human erythropoietin (r-HuEPO) was administered to 24 anaemic pre-dialysis patients with end-stage renal disease. R-HuEPO was injected i.v. three times weekly during the first two months (correction phase). Fixed dosages of 50 U/kg, 100 U/kg, and 150 U/kg were used, and each dose group consisted of eight patients. During the subsequent six months r-HuEPO was given once weekly and the dose was adjusted to maintain a stable haemoglobin value (maintenance phase). The mean +/- SD haemoglobin increased from 9.3 +/- 0.6 to 11.1 +/- 1.3 g/dl with 50 U/kg, from 7.9 +/- 1.4 to 11.8 +/- 1.7 g/dl with 100 U/kg and from 8.4 +/- 1.0 to 12.1 +/- 1.1 g/dl with 150 U/kg of r-HuEPO. The two highest dose groups showed a marked reticulocytosis and a transient thrombocytosis. During the maintenance phase haemoglobin remained stable (11.9 +/- 1.1 g/dl) at a mean dose of 199 +/- 139 U/kg of r-HuEPO per week. Blood pressure did not increase, but in nine of eighteen previously hypertensive patients antihypertensive medication was increased. One hypertensive patient developed seizures. No accelerated progression of renal failure could be demonstrated. All patients reported an improved sense of well-being. R-HuEPO is an important new therapeutic agent for the treatment of anaemia of end-stage renal failure that is also effective in pre-dialysis patients.

Adult↗
PubMed1989

Percutaneous transluminal renal angioplasty and renal function.

Renal function was studied before and after percutaneous transluminal renal angioplasty (PTRA) in 79 patients. In a prospective study of 28 patients with unilateral renal artery stenosis, renal function was similar during angiotensin-converting enzyme (ACE) inhibition and after PTRA. In 37 patients with bilateral renal artery stenoses, 9 patients with solitary kidneys and renal artery stenoses and 5 patients with transplant renal artery stenoses, there was no statistical difference in the renal function before and after PTRA. Of the 79 patients studied, 50 had normal renal function before PTRA. In 5 of these renal function decreased, requiring temporary hemodialysis in 1. Of 29 patients with impairment of renal function due to renal artery stenosis, improvement was noted in 14, stabilization of renal function in 11, and decrease of renal function in 4. It is concluded that PTRA is a safe technique that can make life-long drug treatment unnecessary in antihypertensive patients. It can restore or stabilize renal function in renal insufficiency caused by renal artery stenosis. It has to be kept in mind that contrast medium toxicity and cholesterol embolization can induce severe renal insufficiency after PTRA.

Angioplasty, Balloon↗
PubMed1989

Balloon angioplasty of venous structures.

Percutaneous transluminal angioplasty was attempted in 20 patients with stenoses of venous structures. It concerned one stenosis in a native subclavian vein, 12 stenoses in venous bypass grafts and 7 stenoses in hemodialysis-access fistulas. Primary results were excellent for the procedures in the native vein and the venous bypass grafts with success in all patients (13/13). In the arteriovenous fistulas for hemodialysis, dilatation of the venous stenoses was only possible in 5 out of 7 patients. The subclavian vein stenosis did not recur within a follow-up period of 3 years. Of the stenoses in the venous bypass grafts, two lesions reoccluded within one week and 6 lesions recurred within one year. Two of these lesions were successfully redilated so that 6 lesions remain patent with a follow-up of more than one year. Of the 5 successful dilatations in hemodialysis-access fistulas, two lesions recurred within 2 months. Only 3 veins are still accessible for hemodialysis. It is concluded that attempts at balloon dilatation of stenoses in venous bypass grafts or hemodialysis-access fistulas are meaningful in order to prolong the life of these surgical procedures. Recurrence of stenoses is however likely to occur within one or two years.

Angioplasty, Balloon↗