Current management strategies and long-term clinical outcomes of upper extremity venous thrombosis.

UNLABELLED: Essentials Few data exist on outcome of upper extremity deep and superficial vein thrombosis (UEDVT and UESVT). We followed 102 and 55 patients with UEDVT or UESVT, respectively, for a median of 3.5 years. Risk of recurrent venous thromboembolism was low in both diseases, and the mortality high. Postthrombotic symptoms were infrequent and cancer patients had a higher risk of recurrent VTE. SUMMARY: Background There is scant information on the optimal management and clinical outcome of deep and superficial vein thrombosis of the upper extremity (UEDVT and UESVT). Objectives To explore treatment strategies and the incidence of recurrent venous thromboembolism (VTE), mortality, postthrombotic symptoms, and bleeding in patients with UEDVT and UESVT and to assess the prognosis of cancer patients with UEDVT. Patients/methods Follow-up of patients with UEDVT or UESVT, who were enrolled previously in a diagnostic management study. Results We followed 102 and 55 patients with UEDVT and UESVT, respectively, both for a median of 3.5 years. Anticoagulant treatment was started in 100 patients with UEDVT (98%) and in 40 (73%) with UESVT. Nine patients with UEDVT (9%) developed recurrent VTE, 26 (26%) died, 6 (8%) of 72 patients had moderate postthrombotic symptoms, and 5 (5%) experienced major bleeding. One patient with UESVT had a recurrent VTE, 18 (33%) died, none had moderate postthrombotic symptoms, and none had major bleeding. Of the cancer patients with UEDVT, 18% had recurrent VTE vs. 7.5% in non-cancer patients (adjusted hazard ratio 2.2, 95%CI 0.6-8.2). The survival rate was 50% in cancer patients with UEDVT vs. 60% in those without (adjusted HR 0.8, 95%CI 0.4-1.4). Conclusions The risk of recurrent VTE was low in patients with UEDVT, and negligible for UESVT. Mortality was high for both diseases. Postthrombotic symptoms were infrequent and mild. Anticoagulant therapy of UEDVT carried a substantial risk of major bleeding. Cancer patients had a significant risk of recurrent VTE.

Impact of Whole Body Cryotherapy at -110 °C on Subjects with Arterial Hypertension.

Whole body cryotherapy (WBC) in a cryo-chamber as a medical treatment was first established in Japan in the 1980s, later in Central Europe, and is now becoming more popular also in the United States. The exposure to extreme, non-physiological environmental conditions in a cryo-chamber at -110 °C may exceed the normal adaption capacity. The aim of this study was to investigate the effects of WBC on blood pressure (BP) readings in adult subjects with rheumatic disorders and normal or moderately elevated BP. A sample of 23 subjects (8 female, 15 male) which were recruited according to their pathology between the age of 35 and 69 years undergoing 21 WBC applications was divided into three groups: a group of subjects with anti-hypertensive therapy, a group of subjects with mild arterial hypertension without medical treatment, and a normotensive control-group. A total of 483 BP readings were taken immediately before and after each WBC application. The systolic and diastolic BP were recorded, and the mean arterial pressure, and the amplitude of BP were calculated. A statistically significant rise of BP after WBC was found in the whole sample and in the normotensive group. Over the course of time, no significant change of BP behavior was observed, except for normotensive subjects, who showed a wider range in their systolic BP values. Generally accepted exclusion criteria were applied, and in our sample group WBC was safe with respect to unwanted BP alterations for adult subjects under 70 years-regardless of a pre-existing untreated mild or pharmacologically treated arterial hypertension. Greater changes of BP values might infrequently occur, so an individual monitoring of subjects is necessary.

LRP1b shows restricted expression in human tissues and binds to several extracellular ligands, including fibrinogen and apoE-carrying lipoproteins.

OBJECTIVE: To investigate low-density lipoprotein receptor-related protein 1b (LRP1b) expression in human tissues and to identify circulating ligands of LRP1b. METHODS AND RESULTS: Using two independent RT-PCR assays, LRP1b mRNA was detected in human brain, thyroid gland, skeletal muscle, and to a lesser amount in testis but absent in other tissues, including heart, kidney, liver, lung, and placenta. Circulating ligands were purified from human plasma by affinity chromatography using FLAG-tagged recombinant LRP1b ectodomains and identified by mass spectrometry. Using this technique, several potential ligands (fibrinogen, clusterin, vitronectin, histidine rich glycoprotein, serum amyloid P-component, and immunoglobulins) were identified. Direct binding of LRP1b ectodomains to fibrinogen was verified by co-immunoprecipitation. ApoE-carrying lipoproteins were shown to bind to LRP1b ectodomains in a lipoprotein binding assay. Furthermore, binding as well as internalization of very low density lipoproteins by cells expressing an LRP1b minireceptor was demonstrated. DISCUSSION: LRP1b expression in humans appears to be confined to few tissues, which could point out to specialized functions of LRP1b in certain organs. Most of the newly identified LRP1b ligands are well-known factors in blood coagulation and lipoprotein metabolism, suggesting a possible role of LRP1b in atherosclerosis.

Plasma cholesteryl ester transfer protein concentrations predict cardiovascular events in patients with coronary artery disease treated with pravastatin.

OBJECTIVE: The B1B1 variant of the cholesteryl ester transfer protein (CETP) TaqIB polymorphism and high plasma CETP concentrations are associated with favourable angiographic outcomes in pravastatin-treated patients suffering from coronary artery disease (CAD). The purpose of the present study was to test whether CETP TaqIB genotypes and/or plasma CETP concentrations at baseline also predict clinical end-points in patients with CAD. DESIGN: Prospective longitudinal observational study. SETTING: Primary care doctors (n=88) and hospitals (n=7) in Austria. SUBJECTS: A total of 1620 men and women with preexisting CAD were recruited and plasma lipids were determined at study entry. 1389 hypercholesterolaemic patients were included and 1002 patients completed the follow-up. INTERVENTIONS: In all patients treatment with pravastatin was started and patients were followed up for 2 years. MAIN OUTCOME MEASURES: Cardiovascular events. RESULTS: One hundred patients suffered at least one cardiovascular event. We observed significantly more events in patients within the lowest compared with the highest quartile of plasma CETP concentrations (odds ratio 3.20, CI95 1.65-6.23; P=0.001, adjusted for known risk factors of CAD). No significantly different numbers of cardiovascular events were found between CETP TaqIB genotypes. CONCLUSIONS: Plasma CETP concentrations, but not CETP TaqIB genotypes, predict cardiovascular events in patients with CAD treated with pravastatin. Despite higher LDL cholesterol concentrations, high plasma CETP concentrations at baseline are associated with fewer cardiovascular events compared with low plasma CETP concentrations in CAD patients treated with pravastatin.

Flow-mediated vasodilation of the femoral and brachial artery induced by exercise in healthy nonsmoking and smoking men.

OBJECTIVES: We sought to analyze diameter changes of conduit arteries in response to whole-body exercise and hypothesized that this response might be endothelium-dependent and, therefore, impaired in smokers. BACKGROUND: Hyperemia and coincident vasodilation are pivotal mechanisms for meeting the increased metabolic demands of active muscle tissue during physical exercise, but studies in humans are sparse. METHODS: We studied diameter and blood flow of the femoral and brachial arteries in response to a submaximal bicycle exercise test in 10 nonsmoking and 8 smoking healthy male subjects. During an exercise period of 40 min the investigated conduit arteries were periodically scanned in longitudinal sections by high-resolution ultrasound. In the same subjects flow-mediated dilation (FMD) of the brachial artery was recorded by inducing an ischemia through a forearm-occluding cuff. RESULTS: In response to exercise the diameter of the femoral artery significantly increased in both nonsmokers and smokers, with a diminished response in smokers (9.2 +/- 1.9% vs. 4.8 +/- 1.6%, p < 0.001). Flow-mediated dilation of the brachial artery induced by forearm occlusion was also reduced in smoking subjects, revealing a strong correlation between these different methods of FMD (exercise vs. forearm ischemia) (r = 0.88, p < 0.001). In contrast, blood flow increase of the femoral artery was similar in nonsmoking and smoking subjects (392 +/- 77% vs. 382 +/- 109%, p = NS). CONCLUSIONS: Conduit arteries react with a flow-mediated dilation in response to whole-body exercise. The impairment of this vasodilation observed in smokers was strongly related to a decrease of endothelium-dependent dilation induced by forearm ischemia, indicating that endothelial dysfunction represents the underlying mechanism.

Complement activation by HIV-1-infected cells: the role of transmembrane glycoprotein gp41.

To characterize the mechanisms of complement activation by human immunodeficiency virus type 1 (HIV-1)-infected cells, Cl-4 cells stably expressing the envelope glycoproteins of HIV-1 and the parent African green monkey cell line CV-1 were tested for C1q binding and complement activation. While the parent cell line CV-1 only showed a weak spontaneous activation of the alternative pathway, Cl-4 cells additionally triggered the classical pathway of complement activation independent of anti-HIV antibodies by direct C1q binding. Earlier studies had shown different complement activating potential of cells infected with various HIV isolates. Recombinant soluble CD4-induced shedding of gp120 from the surface of HIV-1-infected cells converted a weak activator isolate (MVP-899) into a strong complement activator. The increase in complement activation was paralleled by the concomitant unmasking of a previously hidden gp41 epitope comprising the major complement-activating domain of gp41 (aa. 601-613). Our results strongly suggest that the transmembrane protein gp41 induces the activation of complement on the surface of infected cells as has been described previously for purified HIV-1 virions. Furthermore, we present evidence that the different potential of HIV isolates to activate the complement system on the cell surface is caused by different degrees of spontaneous gp120 shedding by various HIV isolates.

Decay-accelerating factor (CD55) protects human immunodeficiency virus type 1 from inactivation by human complement.

HIV-1, in contrast to animal retroviruses, is not lysed by human complement, but is readily inactivated by the sera from different animal species. To identify a possible species-specific protection mechanism. HIV-1 was expressed in cells of non-human origin. Recombinant HIV-1 virions that could encode the chloramphenicol acetyltransferase (CAT) protein were produced in African green monkey COS-1 cells, mink cells and, as a control, in human HEp-2 cells and were then used to infect CD4-positive target cells. Analysis of the CAT activity of the target cells revealed that fresh HIV-1-negative human serum reduced the infectivity of HIV-1 derived from monkey and mink cells five- to tenfold, but had no effect on HIV-1 produced in human cells. In addition, human serum efficiently lysed HIV-1 produced in non-human cells in contrast to HIV-1 originating from human cells, suggesting lysis as an important mechanism of virus inactivation. Mammalian cells are protected against lysis by homologous complement by membrane-bound regulatory molecules. Two of these complement inhibitors, namely decay-accelerating factor (DAF) and, to a lesser extent, CD59 were found on the surface of HIV-1 virions by means of a virus capture assay. Antibodies against DAF, but not against other host cell molecules found on the viral surface, efficiently blocked the resistance of HIV-1 produced in human cells to human complement. These results suggest that the acquisition of DAF during the budding process from human cells protects HIV-1 in a species-specific way against the attack of human complement.

A novel, complement factor H-related regulatory protein expressed on the surface of human B cell lines.

Complement regulatory proteins present on the surface of various mammalian cells play an important role in controlling homologous lysis, by interacting with C3 (and usually C4). These proteins have a similar structural motif ("short consensus repeat") (Reid, K.B.M., Bentley, R.D., Campbell, R.D., Chung, L.P., Sim, R.B., Kristensen, T. and Tack, B.F., Immunol. Today 1986. 7:230), and the genes encoding them are members of the family of regulators of complement activation. Here we describe a hitherto unknown member of this family, a molecule expressed by B lymphoblastoid cells. This protein is recognized by polyclonal antibodies to factor H and by MAH4, a monoclonal antibody reacting with the N-terminal portion of factor H. The cell surface protein is built up of two disulfide-linked chains of approximately 68 and 75 kDa. Biosynthetic labeling studies confirmed that it is synthesized by B cells only, but not by the investigated lines of other origin. When tested for its functional activity, this molecule was shown to act as cofactor for factor I-mediated cleavage of fluid-phase C3b to C3bi. The protein appears to be encoded by a 3.5-kb mRNA, hybridizing with a cDNA probe coding for the N-terminal portion of factor H. Due to its cross-reactivity with anti-H antibodies, cofactor activity for factor I and hybridization with factor H cDNA, despite its two-chain composition, it is considered a factor H-like protein.

HIV and complement: role of the complement system in HIV infection.

HIV, in contrast to animal retroviruses, is not lysed by human serum but nevertheless the virus as well as virus-infected cells activate the complement system efficiently. HIV activates the classical pathway by binding C1q to the transmembrane protein gp41. On the surface of HIV-infected cells, both the alternative and the classical pathway are activated. Complement-treated HIV has an enhanced ability to infect cells carrying receptors for C3 fragments. By this mechanism complement can target the virus to certain cells, e.g. follicular dendritic cells. HIV-infected complement-coated cells can interact with complement receptor carrying cells and thereby spread the infection or cause the destruction of the infected cells. Due to direct or indirect effects of HIV the complement system is in an activated state and the cellular expression of complement receptors as well as regulatory molecules is modified in the blood of HIV-infected patients.

HIV and human complement: mechanisms of interaction and biological implication.

Human complement, although not lytic for HIV-1, interacts with the virus and is closely involved in the infectious process. It enhances infection in the absence of antibody, and turns neutralizing antibodies into agents which increase viral infectivity. In this review M.P. Dierich et al. summarize available information and discuss possible biological implications.

HIV-1 and HIV-2 isolates differ in their ability to activate the complement system on the surface of infected cells.

OBJECTIVE: To analyse the ability of different HIV-1 and HIV-2 isolates to activate the complement system. DESIGN: H9 cells chronically infected with various HIV isolates and the corresponding purified viruses were tested for complement activation. To identify the molecules responsible for complement activation on the surface of infected cells, the expression of complement inhibitors/regulators and viral proteins on the cell surface was analysed. METHODS: C3 deposition on the cell surface and the expression of viral and cellular antigens were determined by flow cytometry analysis. Complement activation by purified viruses was measured using a complement consumption assay and a C1 activation assay. RESULTS: H9 cells infected with different HIV-1 and HIV-2 isolates showed varying degrees of complement activation on the cell surface, ranging from strong activation and deposition of large amounts of C3 to no increased C3 deposition compared to uninfected cells. The C3 deposition was eliminated by EDTA and reduced in the presence of EGTA. In contrast, all purified viral isolates tested activated the complement system in a comparable manner. While the expression of MCP, DAF and CD59 was not modified after infection with different viral isolates, the reaction of the infected cells with a monoclonal antibody (3D6) directed against a gp41 epitope (amino acids 601-620) was found to correlate with the complement activation on the cell surface. CONCLUSIONS: Some HIV-1 as well as HIV-2 isolates activate the complement system on the surface of infected cells independent of anti-HIV antibodies, while other isolates fail to do so. Complement activation on the cell surface is mediated by the alternative and, to a lesser extent, the classical pathway. The differences in complement activation on the cell surface are not caused by a modified expression of membrane-bound complement inhibitors/regulators. C3 deposition on the cell surface correlates with the expression of an epitope lying within the major complement activating domain of gp41 (amino acids 591-620). These results suggest a role of gp41 for complement activation on HIV-infected cells as has been described previously for purified HIV.

Human immunodeficiency virus type 1 activates the classical pathway of complement by direct C1 binding through specific sites in the transmembrane glycoprotein gp41.

Human immunodeficiency virus type 1 (HIV-1), in contrast to animal retroviruses such as murine leukemia virus, is not lysed by human complement. Nevertheless, HIV-1 activates complement via the classical pathway independent of antibody, and C3b deposition facilitates infection of complement receptor-bearing cells. Using gel exclusion chromatography on Sephacryl S-1000, purified virions were found to bind 125I-labeled C1q, but not 125I-labeled dimeric proenzyme C1s. Virions activated the C1 complex, reconstituted from C1q, proenzyme C1r, and 125I-labeled proenzyme C1s, to an extent comparable with that obtained with immunoglobulin G-ovalbumin immune complexes. To determine the activating viral component, recombinant viral proteins were used: in the solid phase, soluble gp41 (sgp41) (the outer membrane part of gp41, residues 539-684 of gp160) bound C1q, but not dimeric proenzyme C1s, while gp120 was ineffective. In the fluid phase, sgp41 activated the C1 complex in a dose- and time-dependent manner, more efficiently than aggregated Ig, but less efficiently than immune complexes. To localize the C1 activating site(s) in gp41, synthetic peptides (15-residue oligomers spanning amino acids 531-695 of gp160) were used. Peptides covering positions 591-605 and 601-620 and, to a lesser extent, positions 561-575, had both the ability to bind C1q and to induce C3 deposition. These data provide the first experimental evidence of a direct interaction between the C1 complex and HIV-1, and indicate that C1 binding and activation are mediated by specific sites in gp41.

Anti-viral antibodies in HIV (HTLV-III) infection possess auto-antibody activity against a CH1 domain determinant in human IgG: possible immunological consequences.

Two regions of the envelope glycoprotein gp120 of the human immunodeficiency virus were shown to have a significant degree of homology to human immunoglobulin-gamma heavy-chain constant domains. We have now synthesized three short linear peptides, the first representing a sequence within the CH1 domain, the second an analogue of it, and the third representative of a region within the viral gp120. Polyclonal antibodies against these peptides were raised in rabbits and used to demonstrate that they all reacted well with human native IgG. Vice-versa, we observed the reaction of these antisera to the virus in an ELISA system. The proportion of sera reacting with the human gamma-chain peptide was significantly higher in HIV-positive individuals than in HIV-negative individuals, suggesting production of anti-viral antibodies in AIDS patients with auto-antibody activity against a CH1 domain determinant in human IgG.