Interleukin-4 stimulates human monocytes to produce tissue-type plasminogen activator

Tissue-type plasminogen activator (t-PA) is involved in the lysis of blood clots (fibrinolysis) and is used clinically for this purpose. Endothelial cells are one source of the t-PA present in blood. We report here that interleukin-4 (IL-4) (0.1 to 0.25 U/mL; 1 to 3 x 10(- 11) mol/L), but not interferon-gamma (IFN-gamma), elevates t-PA messenger (m)RNA expression and secretion of t-PA activity by human monocytes, with the maximum response at 2.5 U/mL. Supernatant t-PA activity was detected within three hours of exposure to IL-4 and maximum activity within six hours. Thus, IL-4 may control fibrin deposition at sites of inflammation during cell-mediated immune responses, as well as having a therapeutic role in thrombolysis.     

Low-molecular-weight heparin in the treatment of venous thromboembolism

The low-molecular-weight heparins (LMWHs) have been evaluated in the prevention and treatment of deep-vein thrombosis and pulmonary embolism. LMWHs have been found to be safe and effective in this clinical setting and have advantages over unfractionated heparin. These advantages include less serious and less frequent therapeutic complications. The favorable pharmacokinetic profile of LMWHs compared with heparin has allowed for safe, effective, and convenient treatment of patients with venous thromboembolism. Use of LMWHs ultimately results in considerable cost savings for the health care system.     

Protein-Derived Acetaminophen-Cysteine Can Be Detected After Repeated Supratherapeutic Ingestion of Acetaminophen in the Absence of Hepatotoxicity

Generation of protein-derived acetaminophen-cysteine (APAP-CYS) is reported after ingestion of large and therapeutic dosages of acetaminophen in healthy and in liver-damaged patients. The incidence of protein-derived APAP-CYS adducts in repeated supratherapeutic dosages of APAP is not known. Methods: for 12 months, a standardized and comprehensive questionnaire was used to interview every consecutive patient at a pain management clinic. Patients found to ingest more than 4 g of APAP per day for a minimum of 14 consecutive days at the time of the encounter were invited to have blood drawn for hepatic transaminases and APAP-CYS adduct levels. Twelve subjects out of 990 interviewees met inclusion criteria. Ten of the 12 had measurable protein-derived APAP-CYS, none had evidence of liver injury. Patients that ingest repeated supratherapeutic amounts of APAP over several weeks may generate APAP-CYS protein adducts in the absence of hepatic injury.     

Cardiovascular risk factors in centenarians

Several studies have shown that centenarians have better cardiovascular risk profiles compared to younger old people. Some reports have revealed that cardiovascular diseases (i.e. hypertension, diabetes, angina and/or myocardial infarction) are less common in centenarians respect to 70 and 80 years old persons. In order to explain this evidence, there is a growing number of hypothesis that consider a combination of genetic factors and lifestyle aspects to elucidate the exceptional longevity of centenarians, able to overcome the most frequent mortality cause, which is a cardiovascular event. It has been suggested that a role on this better cardiovascular risk profile may be played by the increasing use of pharmacologic treatments in the elderly population (specially for hypertension and dyslipidemia), but the contribution of drug treatments to promote extreme longevity is not confirmed. Furthermore, centenarians in general have needed fewer drugs at younger ages due to a healthy lifestyle. The importance of the genetic contribution is demonstrated by the inheritance of low-risk cardiovascular profiles in centenarian offspring and lower prevalence of cardiovascular diseases in this population as compared with their spouses or with age-matched subjects without centenarian parents. Another advantage in centenarians' offspring seems to be a delay in the onset for cardiovascular diseases, respect to age- and sex-matched controls. Cardiovascular risk factors mirror the factors that contribute to longevity. Hence, it is not surprising that these risk factors are less prevalent in centenarians when compared to younger old individuals.     

Helicobacter pylori eradication: Novel therapy for immune thrombocytopenic purpura? A review of the literature

Eradication of Helicobacter pylori (H. pylori ) from the gastric mucosa has been associated with improvement of several systemic diseases, including immune thrombocytopenic purpura (ITP). Over the last 5 years, several studies have reported improved platelet counts in H. pylori-positive ITP patients following standard triple H. pylori eradication therapy. Review of published studies in which eradication of H. pylori has been performed in the ITP population indicates an overall response rate of 52% in 193 subjects in whom H. pylori was eradicated. Cohorts from Japan and Italy report higher response rates. There is no established mechanism to explain how this organism, which does not invade the gastric mucosa, could be implicated in the pathogenesis of this immune-based platelet disorder. Several theories including molecular mimicry, platelet aggregation, and immunomodulatory effects of macrolides have been proposed to explain the platelet response to anti-H. pylori therapy. Large randomized-controlled studies enrolling patients from various ethnic backgrounds will be necessary to determine the response rate and mechanism of response and to gain a better understanding of the pathogenesis of ITP.     

Infection of Nippostrongylus brasiliensis induces normal increase of basophils in mast cell-deficient Ws/Ws rats with a small deletion at the kinase domain of c-kit

All basophils, mucosal-type mast cells (MMC) and connective tissue-type mast cells (CTMC) are derived from the multipotential hematopoietic stem cell. Mutations at the c-kit locus resulted in deficiency of MMC and CTMC in both mice and rats. To investigate the role of the c-kit receptor tyrosine kinase for production of basophils, we used white spotting/white spotting (Ws/Ws) mutant rats that have a small deletion at the tyrosine kinase domain of the c-kit gene. When Ws/Ws, nude athymic, and normal (+/+) rats were infected with Nippostrongylus brasiliensis (NB), the number of basophils increased greater than 50- fold in the peripheral blood of Ws/Ws and +/+ rats but did not increase in that of nude rats. Blood histamine concentration increased significantly in Ws/Ws and +/+ rats but did not increase in nude rats. Immature basophils increased greater than 10-fold in the bone marrow of Ws/Ws and +/+ rats but did not increase in that of nude rats. Mature and immature basophils that developed after the NB infection were identified by electron microscopy. The present result confirms that T- cell-derived cytokines are indispensable for the augmented production of basophils and suggests that stimulation via the c-kit receptor may not be necessary for the augmented production.     

A bicistronic retrovirus vector containing a picornavirus internal ribosome entry site allows for correction of X-linked CGD by selection for MDR1 expression

Chronic granulomatous disease (CGD) is an inherited hematologic disorder involving failure of phagocytic cell oxidase to produce superoxide (O2-.), resulting in recurrent infections. The success of retrovirus gene therapy for hematopoietic diseases will be limited both by the efficiency of ex vivo transduction of target cells and by the ability of corrected cells to replace uncorrected cells in vivo. Using MFG-based retrovirus vectors containing oxidase genes, we have previously demonstrated in vitro correction of CGD, but transduction rates were low. In the present study we explore a strategy for providing a selective growth advantage to transduced cells, while retaining the single promoter feature of MFG responsible for high virus titer and enhanced protein production. We constructed a bicistronic retrovirus producing a single mRNA encoding both the therapeutic gene for the X-linked form of CGD (X-CGD), gp91phox, and the selectable human multidrug resistance gene, MDR1 linked together by the encephalomyocarditis virus internal ribosome entry site (IRES). As a control we constructed a bicistronic vector with the polio virus IRES element and using the bacterial neomycin resistance gene (neor) as the selective element. In Epstein-Barr virus transformed B (EBV-B) cells from an X-CGD patient, a tissue culture model of CGD, we show correction of the CGD defect and complete normalization of the cell population using either of these vectors and appropriate selection (vincristine for MDR1 and G418 for neor). Using a chemiluminescence assay of O2-. production, populations of cells transduced with either vector demonstrated initial correction levels of from less than 0.1% up to 2.7% of normal EBV-B cell oxidase activity. With either construct, cell growth under appropriate selection enriched the population of transduced cells, resulting in correction of X-CGD EBV-B cells to a level of O2-. production equalling or exceeding that of normal EBV-B cells. These studies show that a therapeutic gene can be linked to a resistance gene by an IRES element, allowing for selective enrichment of cells expressing the therapeutic gene. Furthermore, the use of MDR1 as a selective element in our studies validates an important approach to gene therapy that could allow in vivo selection and is generalizable to a number of therapeutic settings.