Both alleles of the M235T polymorphism of the angiotensinogen gene can be a risk factor for myocardial infarction.

We have studied the role of three polymorphic genes of the renin-angiotensin system (RAS) as independent risk factors for myocardial infarction (MI) and their correlation with three of the major coronary risk factors: serum cholesterol (CH), hypertension (HT) and smoking (SM). A population of 392 men was genotyped for the M235T polymorphism of the angiotensinogen (AGT) gene, the insertion/deletion of the angiotensin-converting enzyme (ACE) and the all66c of the angiotensin-II type 1 receptor (AT1R), by means of polymerase chain reaction (PCR) and restriction enzyme analysis. It was observed that the T allele frequency increased significantly in the MI with HT, CH, and SM subgroup (0.58 vs 0.31) (p<0.01). In contrast, the M allele frequency was higher in the MI without HT, CH, and SM (0.69 vs 0.42) (p<0.01). A strong association between the MM genotype and MI (p<0.001, odds ratio=4.29, confidence interval=1.95-9.42) was found when age-matched MM control subjects were compared to MI individuals with none of the other known major coronary risk factors. Futhermore, subjects with the MM genotype showed a significantly higher plasma renin activity (PRA) profile than those with the TT genotype (p<0.001). It can be concluded that the M allele is an independent risk factor for MI and the T allele modified the risk when other major risk factors are present.

The genotype interactions of methylenetetrahydrofolate reductase and renin-angiotensin system genes are associated with myocardial infarction.

We analyzed the evolution with age of the frequencies of the I/D polymorphism of the angiotensin I-converting enzyme (ACE), a1166c of the angiotensin II AT1 receptor (AT1R), M235T of the angiotensinogen (AGT) and A225V of their methylenetetrahydrofolate reductase (MTHFR) gene in a healthy (H) population and the subsequent comparison to age- and sex-matched groups of myocardial infarction (MI) subjects. A total of 472 H subjects were divided into three groups < 30, 30-55 and > 55 years old and 277 individuals with MI into two groups 30-55 and > 55 years old. The evolution with age showed that the AGT M allele (P < 0.001) and the MTHFR V allele (P < 0.05) frequency decreased with age in H men. The comparison between healthy and MI groups showed that the MM genotype frequency increased in MI men > 55 years (OR =4.16; 95% CI; 1.72-10.1) The cc genotype showed a similar behaviour (OR = 3.96; 95% CI; 1.21-12.9). In men, all the combinations with MM genotype presented a high risk, with OR values between 1.10 and 7.22. In women, the cc genotype increased in the MI > 55 group (OR = 6.66; 95% CI; 2.02-21.9). All the combinations with the cc genotype showed OR values between 1.71 and 13.3. The MM genotype in men and cc genotype in men and women, are independent risk factors for MI. We propose that the study of the allele frequency evolution in an H population at different ages is essential to determine risk factors for MI in case-control studies, since data from isolated age-matched groups can be misinterpreted.

Quantification by additive RT-PCR of HIV-1 RNA plasma levels in different stages of HIV-1 infection.

In this study, virion-associated RNA was measured in plasma from twenty six patients in various stages of HIV-1 disease by the additive RT-PCR method. Plasma viral RNA levels were inversely correlated (r = -0.72894) with total CD4+ cell counts and directly (r = 0.86964) with serum titre beta 2-microglobulin in chronically infected patients. This additive RT-PCR is based on a mathematical logistic adjustment of the standard curve and the use of an internal standard identical to the target molecule, which represents a control system for the efficiency of RT-PCR and allows a continuous assessment of the accuracy based on the recovery.

Direct quantification of HIV-1 RNA in human plasma by free solution capillary electrophoresis (FSCE).

SUMMARY: The levels of human immunodeficiency virus type 1 (HIV-1) RNA have been directly quantitated, after an isolation step, in plasma from patients with primary HIV-1 infection by free solution capillary electrophoresis (FSCE) with ultraviolet detection. HIV-1 RNA was detected and quantified at physiological levels by measuring the absorbance by FSCE. All the patients with primary infection showed concentrations in a range of 1.08-1.71 x 10(8) virions/ml of plasma. No signals were observed in seronegative donors. This procedure represents a practical alternative to other methods to quantify HIV-1 RNA and may be useful in assessing the efficiency of antiretroviral agents, especially during the early stage when other conventional viral markers are often negative.

Increased expression of scavenger receptor type I gene in human peripheral blood from hyperlipidemic patients determined by quantitative additive RT-PCR.

The scavenger receptors type I and II are mediators for the binding and uptake of chemically modified lipoproteins and are restricted to cells of monocyte origin. These receptors are highly expressed during the process of monocyte to macrophage differentiation. Quantitative mRNA levels of scavenger receptors from peripheral blood mononuclear cells have been analyzed in 29 hyperlipidemic patients and 15 healthy controls. Macrophage scavenger receptor isoforms transcripts were studied in circulating peripheral blood mononuclear cells with a modified RT-PCR method based on the use of a non-modified internal standard and a mathematical logistic adjustment of the standard curve. This method makes it feasible to study the variation in the expression of the scavenger receptors gene in peripheral blood during different physiopathological conditions. We studied the expression of the scavenger receptors gene in different blood cell lines and was present in only those of monocytic origin. The results have shown evidence that levels of scavenger receptor type I transcripts were proportional to apoB/cholesterol levels whereas type II receptors did not show any transcriptional variability. These findings suggest that the cholesterol level exerts a selective up-regulation of the scavenger receptor type I which is detectable by the induced increment of circulating monocytes in the blood of hyperlipidemic patients.

Human herpesvirus-6 and the course of human immunodeficiency virus infection.

The aim of this study is to investigate the relationship between human herpesvirus type 6 (HHV-6) and cytomegalovirus (CMV) infection and progression of AIDS disease. A group of 52 HIV-1-seropositive patients was examined for HHV-6 DNA expression in peripheral blood mononuclear cells and for CMV DNA in serum. We found that 21.1% (n = 52) and 12% (n = 25) of them tested positive for HHV-6 and CMV DNA, respectively. In contrast, only 3.3% (n = 29) and 0% (n = 29) of control healthy HIV-1-seronegative donors tested positive for HHV-6 and CMV, respectively. In light of these results, the possible role of HHV-6 as a cofactor in AIDS development has also been assessed by closely following, over 6 years, the course of an HIV-1-seropositive person who had a dramatic loss in the total number of CD4+ cells along with a spontaneous production of HIV-1 p24 antigen in vitro and who also showed progression to AIDS when coinfected with HHV-6. These observations have spurred our prospective analysis of the possible clinical significance of coinfection with HHV-6 and HIV.

Relationship of IL-2, IL-2R (CD25+), soluble IL-2R and IL-4 with disease activity in SLE patients.

The plasma levels of interleukin-4 (IL-4), interleukin-2 (IL-2), soluble receptor of IL-2 (IL-2R) and T cell expression of IL-2 receptor chain (CD25+) were determined in an attempt to relate these parameters with disease activity in systemic lupus erythematosus (SLE). IL-4, IL-2 and sIL-2R plasma levels of SLE patients were significantly higher than those of the control group (P < 0.05) while CD25+ expression was similar in both groups. Only sIL-2R levels were significantly higher (P < 0.05) in active than in inactive patients.