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Biomedical subjects

R D Henkel

Publications and source records attributed to R D Henkel.

At least 19 recordsLinked to original sources
PubMed2002

Serological evidence of alpha herpesvirus infection in sooty mangabeys.

Contact between sooty mangabeys (SMs) and a pigtailed macaque prompted the serological screening of SMs for evidence of infection with B virus. Serological tests detected SM antibodies that reacted with B virus polypeptides. Additional testing was performed with sera from SMs with no previous contact with macaques. Results from these tests indicated that 56% (33/59) of the SMs had antibodies that reacted with B virus and SA8. SM antibodies also reacted with herpesvirus papio 2 and to a lesser extent with human alpha herpesviruses (HSV-1 and HSV-2). There was an age-related increase in the presence of these antibodies in SMs that was consistent with the serological pattern of reactivity observed in other nonhuman primate species infected with alpha herpesviruses. These data suggest that SMs may be a host for a herpesvirus that is antigenically similar to those viruses present in other Old World nonhuman primates.

Age Factors↗
PubMed1996

Genetic and environmental contributions to cardiovascular risk factors in Mexican Americans. The San Antonio Family Heart Study.

BACKGROUND: The familial aggregation of coronary heart disease can be in large part accounted for by a clustering of cardiovascular disease risk factors. To elucidate the determinants of cardiovascular disease, many epidemiological studies have focused on the behavioral and lifestyle determinants of these risk factors, whereas others have examined whether specific candidate genes influence quantitative variation in these phenotypes. METHODS AND RESULTS: Among Mexican Americans from San Antonio (Tex), we quantified the relative contributions of both genetic and environmental influences to a large panel of cardiovascular risk factors, including serum levels of lipids, lipoproteins, glucose, hormones, adiposity, and blood pressure. Members of 42 extended families were studied, including 1236 first-, second-, and third-degree relatives of randomly ascertained probands and their spouses. In addition to the phenotypic assessments, information was obtained regarding usual dietary and physical activity patterns, medication use, smoking habits, alcohol consumption, and other lifestyle behaviors and medical factors. Maximum likelihood methods were used to partition the variance of each phenotype into components attributable to the measured covariates, additive genetic effects (heritability), household effects, and an unmeasured environmental residual. For the lipid and lipoprotein phenotypes, age, gender, and other environmental covariates accounted in general for < 15% of the total phenotypic variance, whereas genes accounted for 30% to 45% of the phenotypic variation. Similarly, genes accounted for 15% to 30% of the phenotypic variation in measures of glucose, hormones, adiposity, and blood pressure. CONCLUSIONS: These results highlight the importance of considering genetic factors in studies of risk factors for cardiovascular disease.

Adult↗
PubMed1995

An efficient method for routine Epstein-Barr virus immortalization of human B lymphocytes.

A variety of methods exist for the immortalization of B lymphocytes by Epstein-Barr virus due to the simplicity of such techniques to establish cell lines with stable genomic DNA. Two different methods for immortalizing lymphoblastoid cell lines were compared for differences in techniques and materials, time between initiation and immortalization, and success rate of immortalization. An incubation period in Epstein-Barr virus and the use of conditioned media improved immortalization efficiency from 86 to 98% and decreased the time (usually weeks) from culture initiation to cryopreservation. The resulting cell bank was used to produce DNA for genetic studies focusing on the genes involved in non-insulin-dependent diabetes mellitus.

B-Lymphocytes↗
PubMed1993

A primate model of monotypism in atherosclerotic lesions.

We have characterized the expression of allelic variants of X-linked glucose 6-phosphate dehydrogenase (G6PD) in aorta from homozygous, hemizygous, and heterozygous baboons (Papio hamadryas). Fibrous plaques from heterozygous baboons fed a high cholesterol, saturated fat diet contained distributions of G6PD allelic variants that differed from those of normal arterial wall and fatty streaks. The skewed allelic expression patterns in fibrous plaques of heterozygotes reflect decreased cellular heterogeneity in advanced vascular lesions. The tendency toward cellular monotypism in fibrous plaques is similar to that present in advanced human atherosclerotic lesions. Our results suggest that G6PD heterozygous baboons are a unique primate model for investigating the cellular origin of proliferating smooth muscle cells in atherosclerotic plaques.

Alleles↗
PubMed1993

Correlated expression of atrial myosin heavy chain and regulatory light chain isoforms with pressure overload hypertrophy in the non-human primate.

OBJECTIVE: The aim was to determine the extent to which myosin heavy chain and light chain isoform transitions in atrial myocardium are coordinately regulated under pathological conditions in tissue from normal baboons, hypertensive baboons with myocardial hypertrophy, and baboons in which hypertrophy had regressed. METHODS: Quantitative distributions of myosin heavy chain (MHC) and regulatory myosin light chain (MLC2) isoforms in atrial myocardium from 35 adult baboons were determined by electrophoresis under denaturing conditions and laser densitometry. RESULTS: A significant association was observed between the ratios of MHC and MLC2 isoforms in atrial myocardium (r = 0.73, p < 0.001, n = 69). Expressions of alpha MHC and atrial MLC2 (ALC2) isoforms were correlated in atrial myocardium, as were those of beta MHC and ventricular MLC2 (VLC2) isoforms. In a subset of baboons with experimentally induced renal hypertension (n = 12) both beta MHC and VLC2 isoforms were found at higher levels in left atria than were present in normotensive baboons (p = 0.006, n = 15). Left atria from hypertensive baboons with regressed LVH contained intermediate levels of both beta MHC and VLC2 isoforms. CONCLUSIONS: There is tight coupling between the expression of myosin subunit isoforms under pathological conditions from a primate species closely related to humans. The data suggest that the synthesis of these subunits of myosin may be coordinated at the molecular level.

Animals↗
PubMed1989

Alpha-myosin heavy chain cDNA structure and gene expression in adult, fetal, and premature baboon myocardium.

To examine cardiac myosin gene structure and expression in a non-human primate model for human heart development and disease, we have constructed a cDNA library from baboon atrium and used baboon beta-myosin heavy chain (beta-MHC)* cDNA probes to isolate atrial MHC clones. The nucleotide sequence of one such clone, lambda BMHC alpha 3, contains sequences that encode part of the light meromyosin region (LMM) and the 3' untranslated region of the baboon alpha-MHC. To study cardiac MHC gene transcription, we constructed probes from the baboon alpha-MHC cDNA for S1 nuclease analyses of RNA from atria and ventricles. To examine translational regulation of cardiac MHC gene expression, we used monoclonal antibodies (MAb) against specific alpha- and beta-MHC epitopes for Western blot analyses. In atria and ventricles from adult baboons, we detected predominantly alpha- and beta-MHC gene transcripts, respectively. In ventricles from fetal baboons at two stages of development (140 and 160 days gestation), we also detected predominantly beta-MHC gene transcripts and isoforms. To investigate changes induced by parturition, we obtained ventricles from baboons that were prematurely delivered at 140 days gestation and supported for 10 days in an extrauterine environment. In contrast to adult and fetal patterns, we observed an increase in alpha-MHC transcripts and isoforms in ventricles of premature baboons. Because alpha-MHC gene expression is increased in premature baboons (total age of 150 days) compared to their older 160 day fetal counterparts, the induction of ventricular alpha-MHC synthesis must have resulted from factor(s) associated with parturition or prolonged mechanical ventilation rather than at predetermined stages of gestational development.

Amino Acid Sequence↗
PubMed1989

Cardiac beta myosin heavy chain diversity in normal and chronically hypertensive baboons.

We have identified two distinct beta-myosin heavy chains (MHCs) present in baboon myocardium by electrophoresis in gradient pore gels and by Western blots with anti-MHC MAb. The two beta-MHCs have molecular masses of 210 and 200 kD and share several antigenic determinants including an epitope recognized by a beta-MHC-specific MAb. A fivefold increase in the level of the 200-kD beta-MHC was observed in the hypertrophied left ventricles of baboons with chronic (5.3 +/- 0.7 yr) renal hypertension. A 60% increase (P less than 0.01) in BP and a 100% increase (P less than 0.001) in left ventricular mass to body weight ratio occurred in hypertensive baboons compared with normotensive animals. The Ca2+-activated myosin ATPase activity in hypertrophied left ventricles was decreased by 35% (P less than 0.05) compared with controls. Normal levels of the 200-kD MHC were detected in the right ventricles and intraventricular septa of the hypertensive animals. These data suggest that cardiac MHCs of primates may exist in alternative molecular forms that are indistinguishable by nondenaturing gel electrophoresis and that increased concentration of a second beta-MHC is associated with ventricular hypertrophy (r = 0.55). The functional significance and mechanisms that control the concentration of beta-MHC subspecies remain to be determined.

Adenosine Triphosphatases↗
PubMed1988

A microassay for ATPase.

A newly developed microtechnique for quantitating activity of myosin ATPase (EC 3.6.1.32) is more sensitive and less time-consuming than existing spectrophotometric methods. Measurement of ATPase activity using the new method can be accomplished in a final volume of 0.25 ml, allowing the assay to be conducted in individual wells of 96-well microplates commonly used for the enzyme-linked immunosorbent assay (ELISA). The microassay is performed by adding purified myosin to microplate wells followed by addition of ATP to initiate the enzymatic reaction. The reaction is subsequently terminated by addition of an acidic solution containing malachite green and ammonium molybdate. The level of inorganic phosphate produced by enzymatic hydrolysis of ATP is measured by scanning the microplates using a microELISA plate reader. An entire 96-well microplate can be scanned in less than 2 min, and data from the microassay can be transferred directly to a microprocessor for statistical analysis. The microassay is capable of detecting between 0.2 and 3 nmol of inorganic phosphate in a reaction volume of 50 microliter, and the ATPase activity of as little as 10 ng of rat cardiac myosin can be measured. The increased sensitivity compared with that of other spectrophotometric assays and ease of performing the microassay enable a detailed analysis of the enzymatic properties of cardiac myosin to be conducted on large numbers of small tissue specimens. Several kinetic properties of rat cardiac myosin were determined using this technique.

Adenosine Triphosphatases↗
PubMed1986

Antiserum to a synthetic peptide recognizes the HTLV-III envelope glycoprotein.

In a study performed to determine which regions of the human T-cell lymphotrophic virus type III (HTLV-III) may represent vaccine candidates to prevent the acquired immune deficiency syndrome (AIDS), a synthetic peptide corresponding to amino acid sequence 735 to 752 of the precursor envelope glycoprotein of HTLV-III was used to immunize rabbits. The resulting rabbit antiserum to the synthetic peptide specifically recognized the precursor envelope glycoprotein (gp160) of HTLV-III. Human sera positive for antibody to HTLV-III reacted with this peptide. These findings indicate that synthetic peptides can be used to induce an immune response directed against a native envelope glycoprotein epitope of HTLV-III. The data are discussed in terms of using synthetic peptides to identify antigenic determinants involved in the induction of protective immunity and possibly as vaccine candidates against the etiologic agent of AIDS.

Animals↗
PubMed1986

Further characterization of internal image-bearing anti-idiotypic antibodies: specific binding to immunoglobulin receptors on murine hybridoma cells secreting antibodies to hepatitis B surface antigen.

The further characterization of internal image anti-idiotypic antibodies (anti-Id) that represent a potential alternative vaccine candidate for type B viral hepatitis is described. The anti-Id preparation contains an internal image component or related epitope that mimics hepatitis B surface antigen (HBsAg) and binds to murine hybridoma cells that secrete antibodies to HBsAg (anti-HBs). This binding to anti-HBs-secreting hybridomas was partially inhibited by intact HBsAg particles and was associated with the expression of an interspecies idiotype. Immunoprecipitation studies demonstrated that the anti-Id bound to immunoglobulin molecules expressed on the surface of the hybridoma cells. These data suggest that internal image anti-Id, which induces an in vivo antibody response by antigenic mimicry in the absence of HBsAg, binds to anti-HBs molecules on the surface of cells actively secreting anti-HBs. The possible mechanism for internal image anti-Id-based antibody vaccines that mimic the overall conformation of antigens associated with infectious agents is discussed.

Animals↗
PubMed1985

Intracellular transport of high molecular weight intermediates of acid alpha-glucosidase in human fibroblasts.

Two transient, high molecular weight precursors of human acid alpha-glucosidase were detected by immune precipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The high molecular weight precursors were rapidly converted into lower molecular weight forms corresponding to previously identified intermediates of acid alpha-glucosidase. An accumulation of these precursors was observed in fibroblasts treated with monensin and nigericin, suggesting that these precursors are intermediates of acid alpha-glucosidase undergoing transport through the Golgi complex.

Animals↗