Total HO Research Articles

Cynical hostility in adult male twins.

The heritability of hostility as measured by the Cook and Medley Ho scale was assessed in an adult male sample of 60 monozygotic and 61 dizygotic twin pairs. For the total Ho scale, as well as its health predictive component, the results were consistent with a moderate genetic effect. Results are discussed in terms of genetic and environmental influences on the development of this trait, and possible genetic contributions to the association between hostility and subsequent health.

Cook-Medley Hostility scale and subsets: relationship to demographic and psychosocial characteristics in young adults in the CARDIA study.

This report describes the relationships between scores obtained on the Cook-Medley Hostility (Ho) scale and race, education, gender, and age in a sample of 5115 young adult participants in a prospective study of coronary heart disease (CHD) risk factors. Large differences were observed in total Ho scale scores and in six recently identified subsets according to race, education, gender, and age. Young black males with limited education had the highest Ho scale levels (mean = 26.2) while older white females with more education had the lowest levels (mean = 15.5). In all subgroups, education was inversely associated with hostility. The findings suggest a possible mechanism whereby CHD risk is higher in males than females, in the less educated than the more educated, and in blacks than whites. In all race and gender subgroups, total Ho scale scores and the six subsets were positively correlated with negative life events and negatively correlated with social support, supporting a pattern of psychosocial vulnerability found in other studies.

Quantitation of the hydroxyl radical by reaction with dimethyl sulfoxide

This investigation was conducted to validate the use of dimethyl sulfoxide (DMSO) as a quantitative molecular probe for the generation of hydroxyl radicals (HO.) in aqueous systems. Reaction of HO. with DMSO produces methane sulfinic acid as a primary product, which can be detected by a simple colorimetric assay. To evaluate this method for estimating total HO. production, we studied three model systems, including the Fenton reaction, γ irradiation of water, and ultraviolet photolysis of hydrogen peroxide, for which the theoretical maximum yield of HO. could be calculated and compared to measured DMSO oxidation. The results confirm that 0.05 to 1 m DMSO may be used to capture nearly all of the expected HO. radicals formed. Thus, methane sulfinic acid production from DMSO holds promise as an easily measured marker for HO. formation in aqueous systems pretreated with DMSO.

Scatchard analysis of methane sulfinic acid production from dimethyl sulfoxide: A method to quantify hydroxyl radical formation in physiologic systems

A major impediment to the confirmation of free radical mechanisms in pathogenesis is a lack of direct, chemical evidence that oxygen centered free radicals actually arise in living tissues in quantities sufficient to cause serious damage. This investigation was conducted to validate the use of dimethyl sulfoxide (DMSO) as a quantitative molecular probe for the generation of hydroxyl radicals (HO·) under physiologic conditions. Reaction of HO· with DMSO produces methane sulfinic acid (MSA) as a primary product, which can be detected by a simple colorimetric assay. To develop a method for estimating total HO· production, we studied two model systems: the superoxide driven Fenton reaction in vitro, using xanthine oxidase as the source of superoxide, and a computer model of Fenton chemistry. Measured MSA production both in vitro and in the computer modle was a predictable function of the concentrations of DMSO and competing scavengers of HO·, according to the principle of competition kinetics. Both experimental results and model calculations showed that Scatchard analysis may be used to infer total HO· generation, despite the presence of scavengers other than DMSO, such as mannitol. Thus, methane sulfinic acid production from DMSO holds promise as an easily measured marker for HO· formation in biologic systems pretreated with DMSO, and Scatchard analysis of repeated experiments with varying DMSO concentrations can yield an estimate of total HO· generation.

Radiolytic oxidation of cysteine in aerated and oxygen saturated solution: Effect of cysteine, HC1O 4 and formate ion concentrations

G( RSSR)=22.4 and G( H 2 O 2)=13.2 in aerated 5 x10 -2 M cysteine in 1N HC1O 4 solutions are very high and demonstrate that in contrast to the earlier observation of Packer et al., HO 2 radicals react with cysteine in acid solutions. This is in agreement with recent results of Bielski et al. It is observed that G-values are higher at 1N as compared to 0.1N HC1O 4 solutions suggesting higher k HO + 2RSH in higher acid concentrations. G-values have been found to be higher at pH 0.5 and 6.0 as compared to at pH 3.0. The low values have been explained as due to much higher rate constant ratios k HO + 2 HO 2/ k HO 2+ RSH at pH 3–4 as comared to at pH 0.5 and 6.0. In the presence of high formate ion concentration, even though the total HO 2 radicals have increased in the system, G( RSSR) and G( H 2 O 2) are lower than those in its absence. The lowering in G-values could be due to lowering in RS radical yields. This and some more results demonstrate that RS radical is more important than HO 2 radical in propagating the chain reaction in this system.