Biomedical subjects
Publications and source records attributed to M Weber.
We describe a 10-month-old boy with an unclassified form of radial aplasia with absent thumbs, tibia hypo/-aplasia, and partial absence of toes. Only a few cases with similar limb deficiencies have been published. We try to classify the malformations on the basis of embryological considerations and discuss possible differential diagnosis.
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The Swiss League against Rheumatic diseases in collaboration with rheumatologists organized a special educational program for general practitioners. An evaluation questionnaire was filled in by 238 of the 243 participants. With an average value of 4.57 points out of possible 5.0 the new educational concept was very successful. The interactive learning process in small groups seems to be a good alternative to formal lectures.
Chemotactic cytokines of the CC subfamily (CC chemokines) are considered as major mediators of allergic inflammation owing their actions on basophil and eosinophil leukocytes. The monocyte chemotactic protein (MCP) 1 is a potent inducer of mediator release from basophils but is inactive on eosinophils. To obtain information on the structural determinants of the activities of MCP-1, we have synthesized several NH2-terminally truncated analogues and tested their effects on basophils and eosinophils. Through deletion of the NH2-terminal residue, MCP-1(2-76) was obtained, which was a potent activator of eosinophils, as assessed by chemotaxis, cytosolic free Ca2+ changes, actin polymerization, and that induction of the respiratory burst. In contrast, the activity of MCP-1(2-76) on basophil leukocytes was dramatically decreased (50-fold) compared with that of full-length MCP-1. Deletion of the next residue led to total loss of activity on eosinophil and basophil leukocytes. Analogues with three or four residue deletions, MCP-1(4-76) and MCP-1(5-76), were again active on both cells, whereas all further truncation analogues, MCP-1(6-76) through MCP-1(10-76), were inactive. Thus, a minimal structural modification can change receptor and target cell selectivity of MCP-1. Our observations indicate that the recognition sites of CC chemokine receptors on eosinophils and basophils are similar, although they discriminate between MCP-1 and MCP-1(2-76) and suggest NH2-terminal processing as a potential mechanism for the regulation of CC chemokine activities.
The interaction between activated T cells and eosinophils has been proposed to play an important role in the pathogenesis of allergic diseases. T cell-derived cytokines such as interleukin-5 and granulocyte/macrophage colony-stimulating factor inhibit eosinophil apoptosis and may therefore contribute to the development of tissue and blood eosinophilia in these disorders. Withdrawal of these cytokines leads to eosinophil apoptosis in vitro. In contrast, the mechanisms which actively induce apoptosis in eosinophils are at present not completely understood. In this study, we demonstrate that freshly isolated human eosinophils express mRNA and protein for the Fas receptor. Using anti-Fas monoclonal antibody (mAb), we show that Fas activation accelerates apoptotic eosinophil death in vitro. Moreover, treatment of nasal polyps ex vivo with anti-Fas mAb decreased eosinophilic tissue inflammation. However, we observed that blood as well as tissue eosinophils derived from some eosinophilic donors do not express functional Fas receptors, although Fas protein is normally expressed in these cells. This implies that the susceptibility of the Fas receptor is a matter of regulation in eosinophils as previously observed in other systems. These data suggest that Fas ligand/Fas interactions are involved in the regulation of eosinophil apoptosis and that defects in this system could contribute to the accumulation of these cells in allergic and asthmatic diseases.
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HLA-B27 is known to be highly associated with ankylosing spondylitis. Until now, nine B27 subtypes have been sequenced and may contribute in different fashions to ankylosing spondylitis. Additionally, the divergent subtypes may be of clinical importance in bone marrow transplantation with alternative donors. The purpose of this study was to determine the different subtypes of HLA-B27 by a direct sequencing approach. The typing strategy is based on a group-specific amplification of the second and third exon followed by automated fluorescence sequencing of the polymorphic regions. The extensive sharing of sequence motifs between the different B alleles made it impossible to specifically amplify the B27 group under the precondition of including all sequence variations necessary for a postamplification specificity step. Therefore, for setting up a direct sequencing approach of B27, co-amplified B alleles had to be taken into account. In order to get unambiguous sequencing chromatograms without any heterozygous positions, nested sequencing primers were used which selectively matched sequence motifs only present in the second and third exon of the amplified B27 alleles. This strategy allowed in all cases investigated a clear separation of the haplotypes, revealing unequivocal sequencing results. Using this method, we have investigated 93 B27-positive individuals. Sequencing identified the alleles B*2702, 2703, 2704, 2705, and 2707. B*2701, 2706, 2708, and 2709 were not represented in the population studied.
Ferritin protects endothelial cells from the damaging effects of iron-catalyzed oxidative injury. Regulation of ferritin occurs through the formation of an iron-sulfur cluster within a cytoplasmic protein, the iron regulatory protein (IRP) that controls ferritin mRNA translation. Nitric oxide has been shown to inhibit iron-sulfur proteins and is present at vascular sites of inflammation; therefore, we undertook a study to examine the influence of nitric oxide on changes in endothelial cell ferritin content in response to iron exposure, and the subsequent effects on susceptibility to oxidative injury. Iron-loaded endothelial cells (EC) exposed to nitric oxide donors synthesize markedly less ferritin. Treatment of EC with a nitric oxide donor increases IRP affinity for ferritin mRNA concomitant with a loss of cytoplasmic aconitase activity in iron-laden EC. Iron-treated EC exposed to NO donors were resistant to oxidative injury despite their low ferritin content when examined 1 h after the treatment period. In contrast, 24 h later, these same cells become sensitive to oxidants, whereas iron-treated EC that are ferritin-rich continue to be resistant. In conclusion, NO inhibits the increase of EC ferritin after exposure to iron but provides short-term protection against oxidants; ferritin, in turn, provides durable cytoprotection by inactivating reactive iron.
From 1930 to 1994, 54 patients with primary malignant tumors of the sternum were seen. Fifty patients were first seen with a mass, and one half of them also had pain in the sternal region. Two patients had no symptoms at presentation. Among 39 solid tumors were 26 chondrosarcomas, 10 osteosarcomas, 1 fibrosarcoma, 1 angiosarcoma, and 1 malignant fibrous histiocytoma. Of these, 25 were low-grade and 14 were high-grade tumors. Among 15 small cell tumors were 8 plasmacytomas, 6 malignant lymphomas, and 1 Ewing's sarcoma. Partial or subtotal sternectomy was done in 37 patients and total sternectomy in 3. Of the remaining 14 patients, 3 had local excision; 10 had external radiation or chemotherapy without operation, or both; and 1 had no treatment. All but one patient treated by wide resection (N = 40) had some form of skeletal reconstruction of the chest wall defect. Thirty-one (78%) underwent repair with Marlex mesh, and in 25 this was combined with methyl methacrylate. The skin edges were closed per primum in 32 patients; 8 required muscle, omentum, or skin flaps. Resection in chondrosarcomas yielded a 5-year survival (Kaplan-Meier) of 80% (median follow-up, 17 years). The 5-year survival in osteosarcomas was 14%. Resection was curative in 64% of low-grade sarcomas but in only 7% of high-grade sarcomas. In small cell tumors, resection and radiation were helpful for local control; all failures were a result of distant metastases. We conclude that primary sarcomas of the sternum though uncommon are potentially curable by wide surgical excision. With rigid prostheses to repair the skeletal defects, the surgical complication rates are low. Overall survival after complete surgical resection is related to tumor histologic type and grade.
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The efficacy and safety of topiramate 400 mg/day as adjunctive therapy to traditional antieleptic drugs for partial onset seizures with or without secondary generalization were assessed in a double-blind, parallel-group, placebo-controlled trial. Forty-seven patients with at least one seizure per week during an 8 week baseline were randomly assigned to topiramate (N = 23) or placebo (N = 24) double-blind treatment for a 3 week titration and an 8 week stabilization period. Median percent reduction from baseline in monthly seizure frequency during the double-blind phase was not significantly greater in the topiramate group than in the placebo group (41% vs. 1%; P = 0.065). Nevertheless, other efficacy variables evidenced statistically significant differences in favor of topiramate: a greater number of treatment responders (> or = 50% reduction in seizures; 35% vs. 8%; P = 0.033); better investigator (P = 0.002) and patient (P = 0.021) global assessments; and greater reductions in secondarily generalized seizures compared to placebo (P = 0.002). The most commonly reported topiramate treatment-emergent adverse events were somnolence, fatigue, abnormal vision, weight decrease, and anxiety. Most adverse events were mild or moderate in severity. Among 7 withdrawals due to limiting adverse events, 6 were CNS-related (in 5 topiramate-treated patients). Results of this trial strongly suggest that topiramate 400 mg/day is effective and well tolerated in the treatment of refractory partial epilepsy.
Goodpasture's syndrome is mediated by immunopathogenic autoantibodies to the alpha 3 NC1 domain of type IV collagen. It is not known whether collaborating T-cells participate in this autoreactive response. Here we describe the first T-cell clone isolated from a Goodpasture patient autoreactive to alpha 3 type IV collagen of glomerular basement membrane. To investigate cellular autoreactivity, T-cells from Goodpasture patients or controls were isolated and stimulated by purified native or recombinant type IV collagen proteins and synthetic oligopeptides. Cell surface markers, the T-cell receptor repertoire, and MHC-restriction were analyzed. T-cell clones specific for the alpha 3 (IV) NC1 domain were established in two Goodpasture patients, but not in controls. One of the three CD8+ T-cell clones was characterized further. It was MHC class I restricted (HLA-A11) and expressed the T-cell receptor V beta 5.1. chain. This clone specifically recognized a motif at the N-terminal area of the alpha 3 (IV) NC1 domain (AA 51 to 59: GSPATWTTR). We conclude that autoreactive T-cells exists in Goodpasture patients and may play a crucial role in the inflammatory process. T-cell clones are autoreactive to the alpha 3 (IV) NC1 domain. At least for one of the clones, the T-cell epitope is different from the putative antibody-binding site.
Reactive oxygen species are autocrine and paracrine modulators of cell behavior. Hydrogen peroxide, a cellular oxidant, has been shown to stimulate mesangial cell proliferation. In the present study we analyzed the H2O2-induced early signaling events. Immunofluorescence analysis revealed a H2O2 induced dose-dependent increase in tyrosine phosphorylation. Short treatment (2 or 5 min) with 5 mM H2O2 induced a mitogenic response and a significant (P < 0.01) increase in the number of cells compared to non-treated controls. Proteins extracted from H2O2 (0.1 to 10 mM) treated cells were separated on SDS-PAGE and subjected to immunoblot analysis with anti-phosphotyrosine. A dose-dependent induction of tyrosine phosphorylation of 180 kDa, 120 kDa and 60 kDa proteins was observed within 1 to 10 minutes. By sequentially using immunoprecipitation and immunoblotting the 180 kDa tyrosine phosphorylated band was shown to represent both PDGF alpha- and beta-receptors. The tyrosine phosphorylated 60 kDa protein was identified as the cytoplasmic protein tyrosine kinase pp60c-src. The c-src phosphorylation was associated with an inhibition of c-src kinase activity, suggesting phosphorylation of tyrosine 527 in the c-src regulatory domain. Pretreatment with catalase completely abrogated the H2O2-induced PDGF receptor and c-src tyrosine phosphorylation. These data support the notion that the activation of a signaling pathway involving the PDGF receptors and c-src contributes to the mitogenic effects of reactive oxygen species.
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BACKGROUND: Goodpasture (GP) syndrome is defined by the clinical association of pulmonary haemorrhage with rapidly progressive glomerulonephritis. The disease is caused by pathogenic autoantibodies directed against type IV collagen, which is a major structural component of glomerular basement membranes (GBM). METHODS: The non-collagenous domains (NC1) of all six human type IV collagen alpha chains was produced in E. coli as recombinant fusion proteins with glutathione-S transferase. Sera from 10 patients with different types of anti-GBM nephritis, including GP syndrome, were tested for reactivity with the six proteins using immunoblotting of denatured and reduced proteins and ELISA without reduction. RESULTS: All 10 sera reacted with the alpha 3 (IV) collagen chain by immunoblotting and ELISA. One serum also recognized the alpha 2(IV), alpha 4(IV), alpha 5(IV) and alpha 6(IV) chains by immunoblotting. ELISA measurements revealed reactivity of several other sera with alpha 2(IV), alpha 4(IV) or alpha 6(IV) but not with alpha 5(IV) collagen chains. No reactivity was observed with the alpha 1(IV) chain. CONCLUSION: Autoantibodies in anti-GBM nephritis may not be directed only against the alpha 3(IV) collagen chain and they frequently recognize conformational epitopes.
There are no data on the efficacy of a back school in primary prevention of back pain in the general population or on the characteristics of the population who volunteers. After announcement in the local press, 494 healthy adults volunteered and paid for a back school course in Switzerland. A total of 371 controls were matched for sex, age, profession, nationality and back pain. A statistically significant decrease in numbers of doctor's visits was found by the participants during the following 6 months compared with the controls. However, there were no significant between-group difference in the four remaining parameters (presence and intensity of back pain, drug intake and sick leave). Three-quarters of participants changed their attitudes after the back school. Volunteering for a back pain prevention programme was associated with the presence of back pain problems. Reasons for volunteering are further discussed. Overall, the results of this study showed that a back school for the general population may not solve the problem of low back pain, but improves self-help in a subgroup of the population.
Human intestinal trefoil factor, hITF, a secretory polypeptide found mainly in the human gastrointestinal tract, is a member of the newly characterized trefoil factor or P-domain peptide family representing putative growth factors. Here we describe the identification of this gut peptide in the human brain and pituitary. With reverse transcriptase polymerase chain reaction, we were able to isolate and clone the transcript from human hypothalamus. An antibody generated against a synthetic peptide derived from the carboxyl terminus of hITF was used for immunohistochemical studies of appropriate tissue sections. Neurons expressing hITF were identified in two magnocellular hypothalamic nuclei, the paraventricular and periventricular nuclei. hITF polypeptide was also observed in Herring bodies of the neurohypophysis and in secretory cells of the adenohypophysis. Double immunostaining with antigrowth hormone antibody showed partial coexistence in a selected subpopulation of adenohypophysial cells. Localization of hITF in the hypothalamo-neurohypophysial system may suggest a modulatory action on the classical magnocellular nonapeptides vasopressin and oxytocin, and further indicates an adenohypophysial importance of this peptide. It is likely that hITF represents a novel neuropeptide of yet unknown function.