Heart rate as a predictor of mortality: the MATISS project

OBJECTIVES

This study sought to verify the independent role of heart rate in the prediction of all-cause, cardiovascular, and noncardiovascular mortality in a low-risk male population.

METHODS

In an Italian population-based observational study, heart rate was measured in 2533 men, aged 40 to 69 years, between 1984 and 1993. Data on cardiovascular risk factors were collected according to standardized procedures. Vital status was updated to December 1997.

RESULTS

Of 2533 men followed up (representing 24,457 person-years), 393 men died. Age-adjusted death rates for 5 heart rate levels showed increasing trends. The adjusted hazard rate ratios for each heart rate increment were 1.52 (95% confidence interval [CI] = 1.29, 1.78) for all-cause mortality, 1.63 (95% CI = 1.26, 2.10) for cardiovascular mortality, and 1.47 (95% CI = 1.19, 1.80) for noncardiovascular mortality. Relative risks between extreme levels were more than 2-fold for all endpoints considered.

CONCLUSIONS

Heart rate is an independent predictor of cardiovascular, noncardiovascular, and total mortality in this Italian middle-aged male population.

[The role of biological monitoring in the evaluation of the risk of from chemical compounds]

Over the years, the assessment of the risk to human health from occupational and environmental exposure to chemicals has become increasingly important. Exposure to chemicals, their biochemical effects and individual susceptibility can be estimated by biological monitoring carried out on potentially exposed subjects. Valid markers are needed to be effectively used within the framework of biological monitoring programs. Quality assurance, which includes all those activities necessary to provide adequate confidence that the results of laboratory test are reliable, is of the utmost importance. Among these activities the participation in external quality assessment schemes is strongly recommended. Biological monitoring has a key role also in the field of human reproduction since the level of exposure to many chemicals which are known or suspected to be reproductive toxicants can be assessed by specialized laboratories.

Change in cardiovascular risk factors during a 10-year community intervention program

The study describes changes in cardiovascular risk factors during 10 years of a community intervention program conducted in a rural area in Central Italy. Two areas were involved, one for treatment and one for reference. In 1983-84, 739 men and 859 women in the treatment area and 942 men and 1045 women in the control area, aged 20-69 years, were screened; total and HDL cholesterol, systolic and diastolic blood pressure, fasting blood glucose, smoking habit, weight and height were measured. Between 1983 and 1993 several intervention activities based on community medicine were carried out in the treatment area. They were based on interaction with the local socio-sanitary institutions and school system in order to influence individual persons, small groups and entire community. Major effort was addressed to mass health education, nutrition education, antismoking-propaganda and detection and treatment of hypertension, diabetes and hyperlipidemia.

Effect of thymine dimer introduction in a 21 base pair oligonucleotide

It is well known that the pyrimidine dimers are the main damage produced by UV radiation on the DNA structure. However, while studies on the photoproduct structure have been carried out extensively, uncertainties still exist on the implication that a single damaging event has on the overall conformation. In particular, the extension of the damage influence on the polynucleotide chain is a matter of debate. This problem is especially important to understanding some steps of the repair mechanisms. In this study we performed a chemical-physical characterization of 21 base pair oligonucleotides containing a single thymine dimer in one strand. Thermodynamic parameters were determined by means of thermal denaturation experiments, and static fluorescence measurements were performed to unequivocally define the primary structure-conformation relationship in this specific case. We used hydroxyl radicals, produced by means of gamma-irradiation of the sample solution, to detect fine structure changes. Our data show that the introduction of a single thymine dimer might cause only a slight distortion of the helix geometry, as judged by the evaluation of the enthalpic and the entropic terms and by the small changes observed in the binding of ethidium bromide to DNA. The modifications in the sugar phosphate backbone subsequent to the damaging event are especially evident, near the thymine dimer, toward the 5'-end direction in the strand containing the dimer.

Influence of defects on the electrophoretic, thermodynamic and dielectric properties of a 21 base pair DNA in solution

The thermodynamic and dielectric properties of a 21 base pair DNA have been evaluated and compared with those of samples with some defects. In particular, fragments in which the absence of a phosphate group (nick) or of two nucleotides (gap) causes chain interruptions were studied. Measurements of ultraviolet absorption as a function of temperature at different oligomer concentrations and at various ionic strengths were performed. Dielectric spectroscopy at radiofrequencies (1 MHz-1 GHz) was applied on aqueous solutions of the duplexes at 5 degrees C, where the solutes are thermally stable. Dielectric dispersions with 30-40 MHz characteristic frequencies were defined. The results of melting experiments indicate a thermal destabilization of the oligomers containing the defects. Electrophoretic data and the dielectric results show that the conformations of the nicked and control samples are very similar, while the oligomer with a gap is more compact with a different charge distribution at the ends.