It is becoming increasingly apparent that articular cartilage growth is achieved by apposition from the articular surface. For such a mechanism to occur, a population of stem/progenitor cells must reside within the articular cartilage to provide transit amplifying progeny for growth. Here, we report on the isolation of an articular cartilage progenitor cell from the surface zone of articular cartilage using differential adhesion to fibronectin. This population of cells exhibits high affinity for fibronectin, possesses a high colony-forming efficiency and expresses the cell fate selector gene Notch 1. Inhibition of Notch signalling abolishes colony forming ability whilst activated Notch rescues this inhibition. The progenitor population also exhibits phenotypic plasticity in its differentiation pathway in an embryonic chick tracking system, such that chondroprogenitors can engraft into a variety of connective tissue types including bone, tendon and perimysium. The identification of a chondrocyte subpopulation with progenitor-like characteristics will allow for advances in our understanding of both cartilage growth and maintenance as well as provide novel solutions to articular cartilage repair.

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P regnancy is associated with increased risk of thrombosis among women with mechanical prosthetic heart valves. 1 The largest literature review of women with a prosthetic heart valve who were on anticoagulation during pregnancy reported that thromboembolic complications occurred in 3.9% of women taking only warfarin, 9.2% of women who received unfractionated heparin in the first trimester followed by warfarin, and one fourth of women treated with unfractionated heparin throughout their pregnancy. Maternal death was observed in these groups in 2%, 4%, and 15%, respectively, and was usually related to prosthetic valve thrombosis (PVT).2 Similarly, 15% of pregnant women developed PVT while using low-molecular-weight heparin. The guidelines suggest optimizing anticoagulation in noncritically ill patients with recent subtherapeutic anticoagulation. Surgery is recommended when anticoagulation fails, for critically ill patients with obstructive thrombosis, or for patients with large (≥10 mm) nonobstructive PVT complicated by embolism. Fibrinolysis is recommended for either critically ill patients when Background-Prosthetic valve thrombosis during pregnancy is life-threatening for mother and fetus, and the treatment of this complication is unclear. Cardiac surgery in pregnancy is associated with very high maternal and fetal mortality and morbidity. Thrombolytic therapy has rarely been used in these patients. The aim of this study is to evaluate the safety and efficacy of low-dose (25 mg), slow infusion (6 hours) of tissue-type plasminogen activator for the treatment of prosthetic valve thrombosis in pregnant women. Methods and Results-Between 2004 and 2012, tissue-type plasminogen activator was administered to 24 consecutive women in 25 pregnancies with 28 prosthetic valve thrombosis episodes (obstructive, n=15; nonobstructive, n=13). Mean age of the patients was 29±6 years. Thrombolytic therapy sessions were performed under transesophageal echocardiography guidance. The mean dose of tissue-type plasminogen activator used was 48.7±29.5 mg (range, 25-100 mg). All episodes resulted in complete thrombus lysis after thrombolytic therapy. One patient had placental hemorrhage with preterm live birth at the 30th week, and 1 patient had minor bleeding. Conclusions-Low-dose, slow infusion of tissue-type plasminogen activator with repeated doses as needed is an effective therapy with an excellent thrombolytic success rate for the treatment of prosthetic valve thrombosis in pregnant women. This protocol also seems to be safer than cardiac surgery or any alternative medical strategies published to date. Thrombolytic therapy should be considered first-line therapy in pregnant patients with prosthetic valve thrombosis.

Our study demonstrates that LMCA-Co is one of the most important and potentially lethal complications of severe PH, and alertness for this risk seems to be necessary in specific circumstances related with PAA. However, long-term benefit from stenting in this setting remains as a controversy.

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Reactive oxygen metabolites play an important role in ischemia-reperfusion related gastric injury. Primary sources of reactive oxygen metabolites seem to be the xanthine/xanthine oxidase system and neutrophils accumulating within the reperfused tissue. Tissue myeloperoxidase activity is an important index of neutrophil accumulation. The purpose of the present study was to clarify the effect of L-carnitine on the accumulation of neutrophils and neutrophil-induced gastric mucosal damage in rats exposed to ischemia-reperfusion. Rats were randomly divided into three groups: sham-operated, ischemia-reperfusion and ischemia-reperfusion plus L-carnitine groups. Ischemia was induced by clamping the celiac artery for 30 min and then reperfusion was established for 60 min. Gastric injury was assessed by measuring myeloperoxidase activity in gastric tissue. The neutrophil accumulation and hemorrhagic lesions due to ischemia-reperfusion in gastric mucosa were ascertained in a histological study. L-Carnitine (100 mg kg(-1)) administrated intravenously 5 min before ischemia significantly reduced both the gastric injury and myeloperoxidase activity compared with the ischemia-reperfusion group. The results suggest that L-carnitine provides marked protection against ischemia-reperfusion-related gastric injury which could be due to its ability to reduce neutrophil accumulation in ischemic tissue.

In addition to deaths directly caused by cardiovascular diseases (CVDs), clinical complications that may develop in the postoperative period have important effects on mortality. Contrast-induced acute kidney injury (CI-AKI) is a condition seen after cardiac or radiological evaluations using contrast agents. Up to 25% of CI-AKI is seen after diagnostic or therapeutic interventional procedures performed for cardiovascular disorders. 1,2 Information such as age, weight, diabetes mellitus (DM), hypertension, known renal insufficiency obtained from the patient before the clinical evaluation of procedure can be predictive for CI-AKI development, as well as the amount of contrast agent,