In vivo protein synthetic rates of atrial, ventricular, and pulmonary tissue proteins in aortic constriction, goldblatt, and bromoethylamine models of hypertension

Changes in tissue protein synthesis in hypertension have usually been measured in vitro in heart from acutely hypertensive rats without consideration of changes in atrial or pulmonary tissue or changes occurring in long-standing hypertension. The objective of the study was to investigate the in vivo changes in cardiopulmonary protein synthesis in three different rat models of chronic hypertension. Hypertension in aortic constriction, the Goldblatt model, and the bromoethylamine model were induced in rats for 30 days. At the end of the experimental period, in vivo rates of protein synthesis were measured with a flooding dose of [3H]phenylalanine (a method which effectively considers precursor pools). Concomitant measurements included quantification of contractile protein and RNA and DNA contents. Indices of protein breakdown were also assessed by selective measurement of protease activities. At the end of 30 days, aortic constriction induced marked increases in protein contents of the left ventricle, septum, left atria, and lungs. Accompanying changes included concomitant increases in RNA and DNA contents. Left ventricular myofibrillary, sarcoplasmic, and stromal protein contents increased in the aortic constriction model. Less marked changes occurred in the Goldblatt model, though the left atria were not significantly affected. In contrast, the bromoethylamine model had no effect on the protein or RNA contents of any region. In all cardiac regions of all three models, fractional rates of protein synthesis were not significantly affected. However, protein synthesis increased in the lungs of both the Goldblatt and bromoethylamine models at 30 days. Protease activities were decreased in the left ventricles of all three models at 30 days, with lysosomal protease activities declining in the aortic constriction model and cytoplasmic protease activities declining in the other two models. The failure of chronic hypertension to increase ventricular synthesis rates may represent inherent limitations in the time frame for measuring protein synthesis in vivo. However, at earlier time points (i.e., 10 days), the aortic constriction model was characterized by marked increases in left ventricular and atrial protein contents, RNA contents, and fractional rates of protein synthesis. This was consistent with the supposition that, in acute phases of hypertrophy, rates of protein synthesis increase, whereas in established hypertrophy, synthesis rates remain unchanged or decrease. The applicability of the aortic constriction model was investigated by examining the effects of the angiotensin converting enzyme inhibitor lisinopril (5 mg/kg/day). After 30 days treatment, lisinopril impeded the increase in left ventricular mixed and myofibrillar proteins. This effect was accompanied by an apparent increase in protein synthesis. In conclusion, although all three chronic models are able to induce hypertension, varying degrees of hypertrophy develop, which are more pronounced in the aortic constriction model. Accompanying changes include hypertrophy in the atria, reduced rates of ventricular proteolytic activity, and altered rates of protein metabolism in the lungs.     

Coronary risk factor reduction through biofeedback-aided relaxation and meditation

The effects of behaviour modification through education and biofeedback-aided relaxation and meditation on the levels of blood pressure, pulse rate, smoking habits as well as serum cholesterol, triglycerides, and free fatty acids were studied in 18 normotensive, 18 smoking, and 22 hypertensive patients with 18 normotensive controls.

The results showed significant reduction in blood pressure, in all the treated groups; highly significant reduction in the number of cigarettes smoked by smokers; and reduction in some of the lipids in all the treated groups, but particularly in the hypertensive group. The therapy appears to be feasible and suitable for wider application. This approach is economical, acceptable to patients, and should be explored further.

     

Purification of native alpha-enolase from Streptococcus pneumoniae that binds plasminogen and is immunogenic

Many pathogenic bacteria express plasminogen receptors on their surface, which may play a role in the dissemination of organisms by binding plasminogen that, when converted to plasmin, can digest extracellular matrix proteins. A 45-kDa protein was purified from Streptococcus pneumoniae and confirmed as an alpha-enolase by its ability to catalyse the dehydration of 2-phospho-D-glycerate to phosphoenolpyruvate and by N-terminal sequencing. The activity of alpha-enolase was found in the cytoplasm and in whole cells. Activity was also demonstrated in cell wall fractions, which confirmed that alpha-enolase is a cytoplasmic antigen also expressed on the surface of S. pneumoniae. The plasminogen-binding activity of alpha-enolase was examined by Western blot, which showed that purified alpha-enolase was able to bind human plasminogen. Immunoblots of the purified 45-kDa alpha-enolase with 22 sera from patients with pneumococcal disease showed binding in 15 cases, indicating that pneumococcal enolase is immunogenic.     

Antibody to native human immunodeficiency virus type 1 envelope glycoproteins induced by IIIB and MN recombinant gp120 vaccines. The NIAID AIDS Vaccine Evaluation Group.

The ability of antibody induced by MN and IIIB recombinant gp120 (rgp120) human immunodeficiency virus type 1 (HIV-1) vaccines the bind to oligomeric native and monomeric recombinant HIV-1 envelope glycoproteins (rgp 120) was measured in 25 uninfected, healthy adult volunteers. A major focus was to evaluate the effect of simultaneous and sequential immunization with vaccines representing different strains of HIV-1 on the ability to broaden cross-reactivity of antibodies against these and other HIV-1 strains. A flow cytometric indirect immunofluorescence assay (FIFA) to detect vaccine-induced antibody to envelope glycoprotein expressed by infected and rgp120-coated target cells was used, MN rgp120 HIV-1 vaccine given alone and coadministered with IIIB rgp120 HIV-1 vaccine elicited antibody which bound to cells infected with HIV-1MN, HIV-IIIB, HIV-1RF, and HIV-1-SF2. The presence of envelope glycoprotein-binding antibody detected by FIFA correlated to a moderate degree with functional antibody against HIV-1MN and HIV-IIIB. Priming immunization with IIIB rgp120 HIV-1 vaccine followed by booster injections of MN rgp120 HIV-1 vaccine resulted in increased cross-reactive antibody binding to these and heterologous clade B HIV-1 strains infecting cells. MN rgp120 HIV-1 vaccine given alone was better able to induce cross-reactive antibody to cells infected with heterologous HIV-1 laboratory strains than was IIIB rgp120 HIV-1 vaccine given alone. The vaccines induced binding antibody to rgp120 possessing the amino acid sequence of a clade E HIV-1 strain as measured by enzyme-linked immunosorbent assay. Levels of antibody binding to cells infected with clade B HIV-1 and cells coated with monomeric rgp120 were greater than that induced by HIV-1IIIB-based gp160 vaccines in previous studies.     

Heminested inverse PCR for IS6110 fingerprinting of Mycobacterium tuberculosis strains.

A heminested inverse PCR (HIP) for the amplification of sequences flanking the Mycobacterium tuberculosis insertion sequence IS6110 has been developed. The method depends upon primers that anneal to IS6110 at sites between its 5' end and the closest BsrFI site. The accuracy of HIP was demonstrated by the amplification of sequences within plasmid constructs carrying one or two copies of the insertion sequence IS986 in different orientations. The identities of the amplicons produced from strains carrying a single copy of IS6110 were verified by nucleotide sequencing. Analyses of 204 M. tuberculosis strains including those involved in outbreaks showed that IS6110 HIP is highly discriminatory and reproducible. HIP fingerprinting of these 204 strains generated 136 distinct types, and its discriminatory power was equivalent to that of standard restriction fragment length polymorphism analysis. The method is therefore of value for the rapid fingerprinting of M. tuberculosis strains for epidemiological purposes.