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Unlabelled: Summary. , Background: Vinculin links integrins to the cell cytoskeleton by virtue of its binding to proteins such as talin and F-actin. It has been implicated in the transmission of mechanical forces from the extracellular matrix to the cytoskeleton of migrating cells. Vinculin's function in platelets is unknown., Objective: To determine whether vinculin is required for the functions of platelets and their major integrin, α(IIb) β(3) ., Methods: The murine vinculin gene (Vcl) was deleted in the megakaryocyte/platelet lineage by breeding Vcl fl/fl mice with Pf4-Cre mice. Platelet and integrin functions were studied in vivo and ex vivo., Results: Vinculin was undetectable in platelets from Vcl fl/fl Cre(+) mice, as determined by immunoblotting and fluorescence microscopy. Vinculin-deficient megakaryocytes exhibited increased membrane tethers in response to mechanical pulling on α(IIb) β(3) with laser tweezers, suggesting that vinculin helps to maintain membrane cytoskeleton integrity. Surprisingly, vinculin-deficient platelets displayed normal agonist-induced fibrinogen binding to α(IIb) β(3) , aggregation, spreading, actin polymerization/organization, clot retraction and the ability to form a procoagulant surface. Furthermore, vinculin-deficient platelets adhered to immobilized fibrinogen or collagen normally, under both static and flow conditions. Tail bleeding times were prolonged in 59% of vinculin-deficient mice. However, these mice exhibited no spontaneous bleeding and they formed occlusive platelet thrombi comparable to those in wild-type littermates in response to carotid artery injury with FeCl(3) ., Conclusion: Despite promoting membrane cytoskeleton integrity when mechanical force is applied to α(IIb) β(3) , vinculin is not required for the traditional functions of α(IIb) β(3) or the platelet actin cytoskeleton., (© 2010 International Society on Thrombosis and Haemostasis.)

The molecular mechanisms that regulate the cardiac hypertrophic response and the progression from compensated hypertrophy to decompensated heart failure have not been thoroughly defined. Alteration in cardiac extracellular matrix is a distinguishing characteristic of these pathological processes. Integrins, cell surface receptors that mediate cellular adhesion to the extracellular matrix, are signaling molecules that possess mechanotransduction properties. Therefore, we hypothesized that integrins are likely candidates to play an important role in cardiac function. To test this hypothesis, transgenic mice were constructed in which normal integrin function was disrupted by expression of a chimeric molecule encoding the transmembrane and extracellular domains of the Tac subunit of the IL-2 receptor, fused to the cytoplasmic domain of beta(1A) integrin (Tacbeta(1A)). Using the alpha myosin heavy chain promoter to target expression of this chimera to the cardiac myocyte, transgenic mice were generated that had varied levels of transgene expression. Multiple transgenic founders that expressed the transgene at high levels, died perinatally and exhibited replacement fibrosis. Lines that survived showed 1) hypertrophic changes concordant with reduction in endogenous beta(1) integrin levels, or 2) reduced basal contractility and relaxation as well as alterations in components of integrin signaling pathways. These data support an important role for beta(1) integrin in normal cardiac function.

Background/aims: We characterized immunoreactive B-cell domains of hepatitis C virus (HCV) envelope proteins E1 and E2 by a peptide ELISA using sera of patients who were infected by the same isolate of HCV (HCV-AD78)., Methods: Fifty-four overlapping peptides which corresponded to the sequence of E1 and E2 of isolate HCV-AD78 were used to detect specific antibodies. Three groups of HCV-AD78 related sera were analyzed. Two groups were from sera obtained at early time points of infection (months 4-15) from patients who later resolved infection (group A), or who later developed chronic disease (group B). Group C sera were from later time points of chronic disease. As a control, sera of chronic HCV patients who did not have HCV-AD78 infection were also analyzed (group D)., Results: In group A, 25 of the 54 peptides produced OD405 above the cut-off, whereas 17 peptides produced such values in group B. Only 10 and 3 peptides yielded such values in groups C and D, respectively. The overall prevalence of antibodies against peptides was high in the early phase of infection (means of 28.7+/-14.8% and 25.9+/-14.5% in groups A and B, respectively). At later time points of chronic infection (group C), the overall prevalence was lower (mean 18.6+/-15.4%). Group D sera produced the lowest overall prevalence (mean 13.2+/-14.1%). Three peptides, covering aa271-290, aa481-500 and aa551-570, were recognized significantly more frequently (p<0.05) by group A sera than group B sera., Conclusions: We conclude that more linear epitopes of the HCV envelope are recognized with a high prevalence of antibodies, as was suggested previously. However, most B-cell domains of the HCV envelope induce a similarly high antibody response in patients who resolve infection or develop chronic disease.

Nonbacterial thrombotic endocarditis (NBTE) is difficult to detect antemortem and is often not suspected until embolic events occur. Transthoracic echocardiography is useful in diagnosing NBTE, but it may be limited by suboptimal imaging and resolution. Herein we describe the first reported case of NBTE diagnosed by transesophageal echocardiography. As early detection and treatment may avert significant embolic complications, transesophageal echocardiography should be strongly considered if other techniques are nondiagnostic and clinical suspicion of NBTE remains high.

Twenty-five extracted human maxillary central incisors were randomly divided into five equal groups. Crowns were removed 1 mm incisal to the cementoenamel junction. Endodontic treatment was carried out and each tooth was affixed with two strain gauges. The strain gauge wires were connected to a Wheatstone Bridge circuit. Each group of five teeth was restored with either a Para-Post Plus (the control post), Flexi-Post, Vlock post, Kurer Fin Lock Anchor, or a Radix Anchor. Strains generated during post placement were recorded and compared for the five groups using a one-way analysis of variance. The maximum strains accompanying placement of the Kurer Fin Lock Anchor and the Radix Anchor were significantly higher than those induced by placement of the other posts. Also, when the threaded posts were allowed to contact the bottom of the prepared channel, high strains resulted.

Elevated plasma levels of apolipoprotein B (apoB) may predispose to development of premature coronary atherosclerosis. We have identified the first well localized domain of the apoB gene which can effect negative regulation of its transcription. This region binds trans-activating factors present only in apoB producing cell lines. Mutagenesis of this region causes up-regulation of its transcriptional activity. We have termed this element apoB upstream suppressor site (aBUSS) and its trans-activators the apoB repressor proteins (ARP). aBUSS and ARP may play important roles in the transcriptional modulation of apoB.

Two patients underwent resection and replacement of the ascending aorta using a low-porosity Teflon graft anastomosed with silk suture. In both patients false aneurysms developed that required operation 13 and 23 years postoperatively. The clinical courses of these patients, along with data from the literature, suggest that the combination of a low-porosity Teflon graft and a silk suture anastomosis presents a major potential hazard for the development of anastomotic false aneurysm.