Bradykinin receptor gene variant and human physical performance.

Accumulating evidence suggests that athletic performance is strongly influenced by genetic variation. One such locus of influence is the gene for angiotensin-I converting enzyme (ACE), which exhibits a common variant [ACE insertion (I)/deletion (D)]. ACE can drive formation of vasoconstrictor ANG II but preferentially degrades vasodilator bradykinin. The ACE I allele is associated with higher kinin activity. A common gene variant in the kinin beta(2) receptor (B(2)R) exists: the -9 as opposed to +9 allele is associated with higher receptor mRNA expression. We tested whether this variant was associated with the efficiency of muscular contraction [delta efficiency (DE)] in 115 healthy men and women, or with running distance among 81 Olympic standard track athletes. We further sought evidence of biological interaction with ACE I/D genotype. DE was highly significantly associated with B(2)R genotype (23.84 +/- 2.41 vs. 24.25 +/- 2.81 vs. 26.05 +/- 2.26% for those of +9/+9 vs. +9/-9 vs. -9/-9 genotype; n = 25, 61, and 29, respectively; P = 0.0008 for ANOVA adjusted for sex). There was evidence for interaction with ACE I/D genotype, with individuals who were ACE II, with B(2)R -9/-9 having the highest DE at baseline. The ACE I/B(2)R -9 "high kinin receptor activity" haplotype was significantly associated with endurance (predominantly aerobic) event among elite athletes (P = 0.003). These data suggest that common genetic variation in the B(2)R is associated with efficiency of skeletal muscle contraction and with distance event of elite track athletes and that at least part of the associations of ACE and fitness phenotypes is through elevation of kinin activity.     

Ciprofibrate therapy in patients with hypertriglyceridemia and low high density lipoprotein (HDL)-cholesterol: greater reduction of non-HDL cholesterol in subjects with excess body weight (The CIPROAMLAT study)

Background

Microalbuminuria and subsequent progression to proteinuria and nephropathy is associated with increased oxidative stress, increased inflammatory cytokines and increased cardiovascular (CVD) risk. The common functional IL-6 -174G>C gene variant is also associated with elevated levels of inflammatory cytokines and CVD risk.

Methods

The aim of this study was to examine the association between the IL-6 -174G>C gene variant with plasma total antioxidant status (TAOS) in 552 subjects with type 2 diabetes in relation to urinary protein excretion.

Results

In subjects free from CVD, there was a significant interaction between urinary protein excretion (normoalbuminuria/ microalbuminuria/proteinuria) and the -174C allele (compared to -174GG) in determining plasma TAOS (p value for interaction = 0.03). In the -174C allele carriers there was a significant association between plasma TAOS and urinary protein excretion: normalbuminuria v microalbuminuria v proteinuria: 44.30% ± 11.32 vs. 39.74% ± 14.83 vs. 37.93% ± 16.42, ANOVA p = 0.025. In those with CVD, no interaction or association was observed with the -174C allele (p = 0.246).

Conclusion

The IL-6 -174G>C gene variant is associated with differences in plasma oxidative stress in response to altered protein excretion in subjects with type 2 diabetes.     

Site-specific genomic (SSG) and random domain-localized (RDL) mutagenesis in yeast

Background  

A valuable weapon in the arsenal available to yeast geneticists is the ability to introduce specific mutations into yeast genome. In particular, methods have been developed to introduce deletions into the yeast genome using PCR fragments. These methods are highly efficient because they do not require cloning in plasmids.     

Aryl tetrahydropyridine inhibitors of farnesyltransferase: bioavailable analogues with improved cellular potency

Inhibitors of farnesyltransferase are effective against a variety of tumors in mouse models of cancer. Clinical trials to evaluate these agents in humans are ongoing. In our effort to develop new farnesyltransferase inhibitors, we have discovered bioavailable aryl tetrahydropyridines that are potent in cell culture. The design, synthesis, SAR and biological properties of these compounds will be discussed.     

Effects of different beta73 amino acids on formation of 14-stranded fibers of Hb S versus double-stranded crystals of Hb C-Harlem

Hb S (alpha(2)beta(2)(6Glu-->Val)) forms polymers, while Hb C-Harlem (alpha(2)beta(2)(6Glu-->Val,73Asp-->Asn)) forms crystals upon oversaturation. Since the only difference between the two is the beta73 amino acid, it follows that this site is a critical determinant in promoting either polymerization or crystallization. Beta73 Asp in Hb S forms a hydrogen bond with beta4 Thr, while beta73 Asn in Hb C-Harlem may inhibit this interaction as well as increase the hydrophobicity at the EF helix beta6 Val acceptor sites. Two new beta73 Hb S variants (beta73 His and Leu) were constructed and analyzed to define other amino acids facilitating formation of Hb S-like polymers versus Hb C-Harlem-like crystals. The two variants that were chosen were expected to either (1) enhance formation of the beta73-beta4 hydrogen bond (beta73 His) or (2) inhibit it and increase the hydrophobicity of the EF helix beta6 Val acceptor sites (beta73 Leu). beta73 His Hb S formed fibers but at a lower concentration than Hb S, while beta73 Leu Hb S formed crystals but at a higher concentration than Hb C-Harlem. The solubility of beta73 His Hb S was (1)/(7) of that of Hb S, while the solubility of beta73 Leu Hb S was similar to that of Hb C-Harlem. The delay time prior to polymer or crystal formation depended on Hb concentration. The delay time for beta73 His Hb S was 10(5)-fold shorter than that for Hb S, while that for beta73 Leu Hb S was 10(5)-fold longer in 1.0 M phosphate buffer. NMR results indicate beta73 amino acid changes induce alteration in the beta-chain heme pocket region, while CD results indicate no change in the helical content of the variants. These results suggest that enhancing the beta73-beta4 hydrogen bond and/or induced changes in the heme pocket by the beta73 Asp to His change facilitate formation of Hb S-like fibers. Our results also suggest that removal of the beta73-beta4 hydrogen bond and enhancing the hydrophobicity of the EF helix beta6 Val acceptor sites by the beta73 Asp to Leu or Asn changes delay nuclei formation and facilitate formation of Hb C-Harlem-like crystals.     

Zooprophylaxis or zoopotentiation: the outcome of introducing animals on vector transmission is highly dependent on the mosquito mortality while searching

Background

Zooprophylaxis, the diversion of disease carrying insects from humans to animals, may reduce transmission of diseases such as malaria. However, as the number of animals increases, improved availability of blood meals may increase mosquito survival, thereby countering the impact of diverting feeds.

Methods

Computer simulation was used to examine the effects of animals on the transmission of human diseases by mosquitoes. Three scenarios were modelled: (1) endemic transmission, where the animals cannot be infected, eg. malaria; (2) epidemic transmission, where the animals cannot be infected but humans remain susceptible, e.g. malaria; (3) epidemic disease, where both humans and animals can be infected, but develop sterile immunity, eg. Japanese encephalitis B. For each, the passive impact of animals as well as the use of animals as bait to attract mosquitoes to insecticide was examined. The computer programmes are available from the author. A teaching model accompanies this article.

Results

For endemic and epidemic malaria with significant searching-associated vector mortality, changing animal numbers and accessibility had little impact. Changing the accessibility of the humans had a much greater effect. For diseases with an animal amplification cycle, the most critical factor was the proximity of the animals to the mosquito breeding sites.

Conclusion

Estimates of searching-associated vector mortality are essential before the effects of changing animal husbandry practices can be predicted. With realistic values of searching-associated vector mortality rates, zooprophylaxis may be ineffective. However, use of animals as bait to attract mosquitoes to insecticide is predicted to be a promising strategy.     

Estimating domain orientation of two human antibody IgG4 chimeras by crystallohydrodynamics

A modified crystallohydrodynamic approach introduced in 2001 is applied to two human IgG4 constructs from mouse IgG1. The constructs were point mutants of the chimeric antibody molecule cB72.3(4): cB72.3(4A), devoid of inter-chain disulfide bridging, and cB72.3(4P), which has full inter-chain bridging. As before, the known crystallographic structures for the Fab and Fc domains were combined with the measured translational frictional ratios to obtain an estimate for the apparent time-averaged hydration of the domains and hence for that of the intact molecule. The original approach was modified with the hydrated dimensions of the domains being applied, rather than the anhydrous crystallographic dimensions, for assessing the inter-domain orientations using the algorithms HYDROSUB and SOLPRO. Both chimeric IgG4 molecules were found to have open, rather than compact, structures, in agreement with the previous study on wild-type human IgG4. The insertion of a frictionless connector between the domains was necessary, however, for representing the cB72.3(4A) chimera. It therefore appears that the inter-chain disulfide bonds act as physical constraints in the cB72.3(4P) chimera, forcing the antibody domains together and producing a less elongated structure than that of cB72.3(4A). The open structures produced for the two IgG4 chimeras showed similarity to those structures identified for murine IgG1 and IgG2a molecules through X-ray crystallography.Presented at the conference for Advances in Analytical Ultracentrifugation and Hydrodynamics, 8–11 June 2002, Grenoble, France