Pathogenesis of systemic scleroderma: immunological aspects

Systemic sclerosis (SSc) is a connective tissue disorder that is characterized by excessive collagen synthesis by fibroblasts and by vascular hyperreactivity and obliteration phenomena. Excessive collagen production is the consequence of abnormal interactions between endothelial cells, fibroblasts and mononuclear cells. Immunological abnormalities are present very early in the development of SSc. Mononuclear cells, particularily macrophages and T lymphocytes play a prominent role in fibroblast activation and collagen synthesis through the cytokines they produce. Thus, lymphocytic infiltrates in the skin and in the lung are preferentially composed of CD8+ T lymphocytes, that produce important amounts of interleukin 4 (IL-4). The effects of IL-4 are added to these of transforming growth factor B (TGF-B) and connective tissue growth factor (CTGF) that stimulate collagen synthesis by fibroblasts. T lymphocytes produce important amounts of gamma interferon (INF-gamma) that is the best inhibitor of collagen synthesis by fibroblasts. However, the inhibitory effect of INF-gamma on collagen synthesis is diminished in SSc patients. Numerous autoantibodies can be evidenced in the serum of SSc patients. Three of them are specific for SSc and mutually exclusive: anti-centromere antibodies (Ab) in limited SSc, anti-Scl70 Ab in diffuse SSc and anti-RNA polymerase III Ab in diffuse SSc with renal involvement. These autoantibodies are good prognosis markers but their pathogenic role remains uncertain.     

10-year results of anastomoses of the left internal mammary artery to the anterior interventricular artery. Angiographic and radionuclide controls

The long term patency of left internal mammary artery graft is better than that of saphenous vein graft. The aim of this study was to determined if this high patency rate was accompanied by a satisfactory myocardial perfusion. Among 143 patients treated with an internal mammary artery graft on the left anterior descending artery between 1972 and 1976, 42 patients underwent coronary angiogram and exercise tomoscintigraphy (thallium 201) over 10 years after surgery. The left internal mammary artery was patent in 92% without any atheromatous lesions. The myocardial perfusion in the area supplied by the left anterior descending artery was normal in 74%. A slight ischemia appeared during exercise in 19% without any clinical symptoms. This long term study shows excellent anatomical results correlated with a good myocardial perfusion during exercise in most cases.     

Post-cholecystectomy amputation neuroma of the common bile duct with obstructive jaundice

Amputation neuroma of the common bile duct after surgery is a rare and mostly asymptomatic lesion. A 60-year old patient presented with obstructive jaundice three months after a cholecystectomy for symptomatic gallstones. Imaging investigations showed common extrahepatic bile duct stenosis. Surgical resection of the stricture with biliodigestive anastomosis was performed. Histological examination of the surgical specimen revealed an amputation neuroma. Despite its rarity, amputation neuroma of the common bile duct should be considered in patients with post-cholecystectomy syndrome following liver or extrahepatic bile duct surgical procedures.     

Anti-cardiolipin antibody from a patient with antiphospholipid syndrome (APS) recognizes only an epitope expressed by cardiolipin/beta 2-glycoprotein-I (beta 2GPI) complex and induces APS

OBJECTIVE: As the antiphospholipid syndrome (APS) is characterized by antibodies which bind negatively charged phospholipids either directly or mainly through different target epitopes located on the beta-2-glycoprotein-I (beta 2GPI) molecule, the aim of this study is to describe an additional target epitope for anti-cardiolipin binding. METHODS: The binding characteristics of affinity purified anti-cardiolipin antibodies from a patient with monoclonal gammopathy associated with clinically overt APS were studied; inhibition studies were also carried out. These antibodies were used for the active induction of experimental APS. RESULTS: The affinity purified anti-cardiolipin antibodies were found to bind a target epitope created by the complex of cardiolipin/beta 2GPI, while not reacting with a complex composed by another phospholipid (phosphatidylserine/beta 2GPI), as confirmed by direct binding and competition assays. Immunization of naive mice with this unique affinity purified anti-cardiolipin antibody resulted in the induction of experimental APS (thrombocytopenia, prolonged coagulation timed and fetal resorptions). The anti-cardiolipin/beta 2GPI injected mice developed high titers of mouse anti-cardiolipin/beta 2GPI antibodies with the same binding characteristics as the human antibody which was used for disease induction. CONCLUSION: APS is a unique syndrome that is characterized by a diversity of pathogenic anti-phospholipid antibodies which may explain the diversity of clinical manifestations reported in patients.     

Biodegradation of Titanium Implants After Long-Time Insertion Used for the Treatment of Fractured Upper and Lower Jaws Through Osteosynthesis: Element Analysis by Electron Microscopy and EDX or EELS

Twelve patients underwent an osteosynthesis with titanium to treat upper and lower jaw fractures. Six to 12 months later, the miniplates were removed. Tissue samples were analyzed by light and electron microscopy for detection of a metallosis. The analysis showed new bone formation like callus tissue around the miniplates. In some cases small, rounded deposits and accumulation of colloid-like particles located next to bigger titanium artifacts were detected in the cytoplasm of histiocytes and in the matrix of connective tissue. The titanium was identified by elemental analysis using EDX in SEM as well as by EELS and electron diffraction in TEM. Both kinds of particles contain titanium, but they seem to be different in composition and derivation. The bigger particles seem to consist of metallic titanium and sourced by working on the metallic implants during the implantation itself. On the other hand, the colloidal-like, small, rounded particles in tissue macrophages and outside the cells in the matrix of connective tissue are presumably of other origin; for example, they could be derived from biodegradation and chemical conversion of the metallic implants. The titanium miniplates were examined before and after implantation by using ESCA technique and revealed metallic titanium and different compositions with other elements. The amount of titanium load of the tissue was very low in most cases and presumably not of biomedical relevance.