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Biomedical subjects

J Jansen

Publications and source records attributed to J Jansen.

At least 127 records · Page 7Linked to original sources
PubMed1993

Successful allogeneic bone marrow transplantation in an adult with aplastic anemia following orthotopic liver transplantation for non-A, non-B, non-C hepatitis.

A 29-year-old male patient presented with acute liver failure from non-A, non-B and non-C hepatitis, necessitating orthotopic liver transplantation. After operation he developed progressive pancytopenia on the basis of aplastic anemia, which was probably hepatitis associated. After therapy with GM-CSF had failed, he underwent allogeneic BMT from his HLA genotypically identical brother following a conditioning regimen of CY 50 mg/kg x 4 and 500 cGy total lymphoid irradiation. He engrafted promptly but transfusion dependency did not resolve until CMV viremia was treated with ganciclovir. The patient is alive and well 2 years after BMT.

Adult↗
PubMed1993

Soluble receptors for tumour necrosis factor: a putative marker of disease progression in HIV infection.

OBJECTIVE: To assess the value of concentrations of soluble receptors for tumour necrosis factor (sTNFR) as markers for disease progression in HIV infection. DESIGN: We measured concentrations of sTNFR in the serum of 32 HIV-infected male patients in various stages of disease and in 12 healthy male control subjects. Correlations between the levels of sTNFR and CD4+ lymphocyte counts were calculated. RESULTS: Serum levels of sTNFR p55 and p75 were elevated in parallel with severity of clinical stage. sTNFR p55 levels were higher at later stages of HIV infection (Centers for Disease Control stage IV) with or without concurrent illness, whereas sTNFR p75 was already elevated in asymptomatic carriers, compared with controls. There was an inverse correlation between sTNFR concentrations and CD4+ lymphocyte counts. CONCLUSIONS: Our results suggest that sTNFR concentrations could be potential markers for disease progression in HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Detachable shape-memory sewing ring for heart valves.

The novel sewing ring concept consists of a detachable ring snap connection between valve housing or stent and suture cuff. The suture cuff itself is a memory metal ring of nickel-titanium (NiTi) that is embedded within a textile fabric torus. After a special training program the ring can assume two geometric shapes when alternately cooled and heated. Due to this physical property, the sewing ring can be safely fixed within a groove of the housing or stent by changing between room and physiological temperature. This allows the surgeon first to implant the sewing ring followed by arbitrary positioning and final fixation of the valve by the shape-memory effect. Additional advantages are an increased stiffening of the valve base for minimizing potential leaflet dysfunction, and reduced time and risk of implantation, particularly when a reoperation is necessary.

Heart Valve Prosthesis↗
PubMed1992

Antimigraine drug sumatriptan increases blood flow velocity in large cerebral arteries during migraine attacks.

Sumatriptan, a novel selective 5-hydroxytryptamine1d (5-HT1d) receptor agonist, which is highly effective in the acute treatment of migraine attacks, blocks dural neurogenic plasma extravasation and constricts cranial blood vessels in animal experiments. We measured intra- and extracranial blood flow velocities (BFV) with a transcranial Doppler device in 67 patients during a spontaneous migraine attack, before and after treatment with 3 mg or 6 mg subcutaneous sumatriptan or placebo. Sumatriptan, but not placebo, significantly increased BFV (cm/sec) in the internal carotid and middle cerebral arteries on both sides, without detectably changing the BFV in the common and external carotid arteries. The rise in BFV increased with the dose of sumatriptan, parallel to an increase in proportion of patients improved. There were no significant changes in heart rate, blood pressure, or respiratory frequency after treatment with sumatriptan. The increase in BFV probably reflects vasoconstriction of the large basal intracranial arteries, which may be a mechanism for the antimigraine action of sumatriptan.

Adolescent↗
PubMed1991

[Anti-cardiolipin antibody in cerebral infarction].

A 28 year old woman with a previous history of labile hypertension, migraine and transitory cerebral ischemia was admitted with cerebral infarction. One month later she developed livedo reticularis and amaurosis fugax, which led to the diagnosis of Sneddon's disease (livedo reticularis, labile hypertension and neurological symptoms) and the anticardiolipin antibody (ACA) syndrome. Treatment with prednisone and phenprocoumon resulted in lowering of ACA-titers, but the symptoms did not subside until acetylsalicylic acid was added.

Adult↗
PubMed1991

[Antiphospholipid antibodies].

Antiphospholipid antibodies (APA) are acquired, circulating immunoglobulins connected with thrombo-embolic diseases occurring within all organ systems. Whether the antibodies are of pathogenetic relevance for the development of thrombo-embolic states is unresolved. All materials are limited and have yielded contradictory results with regard to important aspects. An increased APTT or PTT does not increase the risk of bleeding in patients with LA, unless abnormalities in the coagulation process are present, e.g. thrombocytopenia or hypoprothrombinaemia. Many questions are unanswered: Should APA be treated in asymptomatic patients? Should patients with APA and relevant symptoms be treated? If so, which treatment should be chosen? And how long should the treatment continue? Are APA of pathogenetic importance or are they markers for another mechanism that causes an immunocoagulopathy? How can it be explained that so many persons produce autoantibodies without becoming seriously ill? In order to clarify the significance of APA it is necessary to standardize tests and to perform extensive, prospective studies, where variations of ACA titres are analysed. Until results from such studies are available, APA should be looked for in patients with recurring arterial or venous thrombosis and in patients with recurring spontaneous abortion with reference to anticoagulant and anti-platelet aggregation therapy if IgG-ACA are elevated over prolonged periods.

Autoantibodies↗
PubMed1991

Upper extremity function in spina bifida.

Poor upper extremity function is often recorded in meningomyelocele patients. Only 2 of the 25 patients we assessed, 5 to 19 years old, showed normal upper extremity function in the clinical neurological examination and a timed hand function test simulating daily activities. Slow performance with unsystematic variability was typical. Poor hand function correlated strongly with hydrocephalus. A trend towards better performance with increasing age may indicate that the difficulties are overcome in some patients. While patients without hydrocephalus showed a near-normal distribution in the seven subtests, patients with hydrocephalus needed more time than normal children. Patients with shunt-treated hydrocephalus did not cope as well as patients without a shunt. Mean age in the three groups differed and may partly explain the differences.

Adolescent↗
PubMed1991

Serum IgG and IgA anti-gliadin antibodies as markers of mucosal damage in children with suspected celiac disease upon gluten challenge.

Serum anti-gliadin antibodies (AGAs) of the IgG and IgA isotypes were determined in 17 children (mean age of 5.6 years) by means of an enzyme-linked immunosorbent assay (ELISA). All children were suspected of celiac disease. They had been on dietary treatment for at least 10 months before they were challenged with gluten. Based on jejunal biopsy findings, 10 of the 17 children had to be considered positive. The sensitivity of the measurement of AGA at 6 weeks after gluten challenge was found to be 90% for IgG, 100% for IgA, and 100% for IgG/IgA combined. The specificity for IgG, IgA, and the IgG/IgA combination was 100, 71, and 100%, respectively. Twelve weeks after gluten challenge, the sensitivity as well as the specificity of AGA determination for IgG, IgA, and IgG/IgA were 100%. It is concluded that testing both IgG AGA and IgA AGA in children suspected of celiac disease is valuable in monitoring the course of the diagnostic provocation protocol and that jejunal biopsies can be abolished. This inexpensive tool can be useful in reducing the number of intestinal biopsies.

Adolescent↗
PubMed1991

New J-3 flexible-leaflet polyurethane heart valve prosthesis with improved hydrodynamic performance.

The aim of this new three-leaflet valve development was to design a leaflet with minimum membrane stresses during performance. This is achieved by manufacturing the valve leaflets shaped almost flat in a medium opening position. Thus, the leaflets have two stable positions, one with maximum opening area and the other with favorable stress distribution in the closed position. The transition between the two end positions is achieved through a two-dimensional rolling motion without buckling and with minimum membrane stresses (bulge forces). The manufacturing technique is dip-coating in polyurethane. Hydrodynamic evaluation of the J-3 valve in steady and pulsatile flow showed minimum pressure drop compared to other commercially available valves. Laser-Doppler-anemometry studies indicated very low shear stresses in the flow field downstream of the valve. In durability tests prototypes have reached lifetimes of up to 17 years. In conclusion, the J-3 valve shows superior hydrodynamic performance thereby reducing potential thrombus formation. Minimization of stresses within the valve leaflets through design could reduce calcification.

Biomechanical Phenomena↗
PubMed1991

[Depersonalization and déjà vu experiences: prevalences in nonclinical samples].

According to the relevant psychological and psychiatric literature, depersonalization and déjà vu experiences are usually viewed as symptoms of severe psychiatric or neurological disorders, especially in schizophrenia, depression and epilepsy. Studies of these phenomena in non-clinical populations are rate. In this article we present the results of several epidemiological investigations. On the basis of survey and interview research, quantitative and qualitative aspects of both phenomena were assessed, as well as the relations with personality variables like emotionality. The results indicate prevalence rates up to 80 percent in non-clinical populations. Based on epidemiological considerations, the question of differentiation between clinical and non-clinical forms of depersonalization and déjà vu is discussed.

Adolescent↗
PubMed1990

[Epidemiology and immunology of trichostrongylosis in cattle and sheep, a synthesis].

The connections between the epidemiology of trichostrongylosis in cattle and sheep and immunological phenomena are discussed. It is concluded that the build-up and the reduction of immunity greatly determine the epidemiology of trichostrongylosis. Regulation of immunity and the development of vaccines produce more questions than good prospects for the time being.

Animals↗
PubMed1990

Effects of a single cleavage in insulin-like growth factors I and II on binding to receptors, carrier proteins and antibodies.

Two somatomedin-like peptides were extracted from Cohn fraction IV of human plasma and brought to homogeneity: one focused at pH 7.8 and the other at pH less than 5.6. Each consisted of two peptide chains interlinked by disulphide bonds. The basic peptide was identical to insulin-like growth factor I (IGF-I) and had a single cleavage in the C-domain before Arg37 [IGF-I(Arg36cl)]. The acid peptide showed identity with IGF-II, with a cleavage in the B-domain before Arg30 [IGF-II(Ser29cl)]. The effects of these cleavages on the characteristics of binding to type I and type II receptor sites, to binding proteins and to antibodies was studied. Binding of IGF-I(Arg36cl) to antibodies directed against the B-domain or against the AD-domain of IGF-I was the same as IGF-I binding. Thus the cleavage does not influence these antigenic sites. In contrast, binding of IGF-I(Arg36cl) to the type I receptor on human and bovine placental cell membranes was markedly decreased compared with IGF-I binding. Binding to the insulin receptor on human placental cell membranes was slightly diminished, whereas the interaction with specific type II receptors on bovine placental cell membranes was unaffected. There was only a minor influence of the cleavage on the region involved in binding to binding proteins. The cleavage in IGF-II(Ser29cl) diminished binding to antibodies directed against the C-domain of IGF-II, compared with binding of IGF-II itself. Binding to receptors (type I and type II) was changed less profoundly. With 125I-labelled IGF-II(Ser29cl), less insulin was needed in order to obtain 50% displacement of the tracer compared with displacement of 125I-labelled IGF-II. The cleaved form of IGF-II probably has a greater affinity towards the common receptor population than does native IGF-II. Binding to binding proteins was not affected by the cleavage in IGF-II.

Animals↗