Reductive activation and radical formation in a series of substituted benzoquinones: Thermodynamic and quantum chemical studies

The reduction of the quinone moiety, which is found in many anti-cancer agents, is still a poorly understood process. It is commonly assumed that the reduction of a quinone by the uptake of two electrons and two protons leads to the active hydroquinone form. For a better understanding of these reactions electrochemical data, obtained for a series of substituted benzoquinones, were analyzed. In addition quantum chemical calculations on the STO-3G level were performed to obtain data for the one- and two-electron reduction.From the electrochemical experiments, thermodynamic data can be obtained which show that the unfavourable free energy of electron uptake is overcome by the favourable binding of protons. Both reactions are influenced by the electronic properties of the substituents, as demonstrated by Hammett-type relationships between the free energy of these reactions and the sigma-para character of these substituents. In these relationships the reaction constant of the electron uptake process has an absolute value which is five times higher than that of the proton uptake.Quantum chemical calculations yielded energy values for the one-electron uptake, as expressed by U(LUMO), and for the total reduction process. Most of the results from these calculations are in accord with the thermodynamic study. The calculations also revealed a conformational change to take place upon reduction of NH₂ and N(CH₂)₂ substituted benzoquinones, which might be important for chemical and biological activity.     

Treatment of scleromyxoedema with hydroxychloroquine

Background: Scleromyxoedema is a rare disease of unknown aetiology that is characterized by deposition of mucin and sclerotic induration of the skin; it is associated with paraproteinaemia. Patients suffer from progressive disability due to immobilization and cosmetic disfigurement. Treatment of scleromyxoedema is a therapeutic challenge. The antimalarial hydroxychloroquine has a rapid and reliable effect in reticular erythematous mucinosis. Patients and methods: Four consecutive patients (two women, two men; median age: 50 years) with scleromyxoedema, three of them with IgG λ paraprotein, were treated with hydroxychloroquine. Treatment was initiated with 600 mg p. o. for 10 days, followed by 400 mg for at least 4 weeks, and 200 mg thereafter. Results: Complete remission of skin manifestations was achieved in one patient, whereas three patients achieved a partial remission of 61+, 5 and 25 months' duration. Notably, three patients felt increased mobility and reduced firmness of skin during the first week of treatment, which was reflected in a rapid reduction in dermal thickness. In one patient, dysphagia was reverted as evidenced by normalization of oesophageal clearance. Paraproteinaemia was not influenced at all. Side effects included one case of electroretinogram abnormalities after 19 months of therapy and one case of leucopenia after 3 months. Conclusion: Hydroxychloroquine is an effective form of therapy for scleromyxoedema, leading to rapid and prolonged alleviation of symptoms.     

Effects of race and socioeconomic status on survival of 1,332 black, hispanic, and white women with breast cancer

Background: A survival disadvantage for black women with brest cancer, which persists after controlling for stage of the disease, has been reported. This study investigates the effects of race and socioeconomic status (SES) on breast cancer survival after controlling for age, stage, histology, and type of treatment. Methods: Kaplan-Meier and Cox proportional hazards models were used to analyze the interaction between race and SES in predicting survival in a sample of 163 black, 205 Hispanic, and 964 white women with breast cancer treated at M. D. Anderson Cancer Center (1987–1991). Results: The results of univariate and multivariate analyses indicate that race was not a significant predictor of survival after adjusting for SES and other confounding factors such as demographic and disease characteristics. SES remained a significant predictor of survival after all adjustments were made. There was no evidence of differences in type of treatment by race or SES if adjustments were made for stage. Conclusions: These results suggest that institutional factors, such as access to treatment, do not explain survival differences by race or SES. Other factors associated with low SES, such as life-style and behavior, may affect survival.     

Increased sensitization in urban vs. rural environment – Rural protection or an urban living effect?

In a population-based longitudinal cohort study, we tested the hypothesis that children growing up in a high-traffic polluted urban area (UA) in the Athens' basin have higher prevalence of allergies and sensitization when compared with those growing up in a Greek provincial rural area (RA). We recruited 478 and 342 children aged 8-10 living in the UA and the RA, respectively. Respiratory health was assessed by a parent-completed questionnaire in three phases: 1995-96 (phase 1), 1999-2000 (phase 2), 2003-04 (phase 3) and skin-prick testing to common indoor and outdoor aeroallergens was performed at phases 1 and 2. Reported asthma and eczema did not differ between the two areas, whereas reported hay fever was persistently more prevalent in the UA than in the RA (16.5%, 17.0%, 18.2% vs. 7.0%, 8.3%, 9.6%, respectively). Sensitization was more prevalent in the UA at both phases (19.0% vs. 12.1% in phase 1, 20.0% vs. 14.1% in phase 2). Residential area contributed independently to sensitization to >or=1 aeroallergens (OR: 0.29; 95% CI: 0.13-0.66; p = 0.003) and to polysensitization (OR: 0.28; 95% CI: 0.10-0.82; p = 0.020) in phase 1. These associations were independent of farming practices. No significant contributions were found in phase 2. Our results suggest that long-term exposure to urban environment is associated with a higher prevalence of hay fever but not of asthma or eczema. The negative association between rural living and the risk of atopy during childhood, which is independent of farming practices, implies that it is mainly driven by an urban living effect.     

Effects of oral N-acetylcysteine on plasma homocysteine and whole blood glutathione levels in healthy, non-pregnant women.

Oral N-acetylcysteine supplementation in nine young healthy females induced a quick and highly significant decrease in plasma homocysteine levels and an increase in whole blood concentration of the antioxidant glutathione. N-acetylcysteine impresses as an efficient drug in lowering homocysteine concentration and might be beneficial for individuals with hyperhomocysteinemia who are at increased risk of cardiovascular disease.     

Threshold for occluded formaldehyde patch test in formaldehyde-sensitive patients

Our purpose was to investigate the eliciting threshold concentration of formaldehyde in formaldehyde-sensitive individuals in the occluded and non-occluded patch teat and to evaluate the relationship in repeated open application test (ROAT) with a product containing a formaldehyde releaser. 20 formaldehyde-sensitive patients and a control group of 20 healthy volunteer were included in the study. Occluded and non-occluded patch tests with formaldehyde solutions form 25 to 10,000 ppm. and ROAT for I week with a leave-on cosmetic product containing on average 300 ppm formaldehyde. Were carried out simultaneously on each subject. In the occluded patch test. 1/2 of the 20 patients only reacted to 10,000 ppm formaldehyde. 9 reacted to 5,000 ppm. 3 reacted to 1.000 ppm. 2 reacted to 500 ppm and I reacted to 25 ppm. No definite positive reactions were observed in the non-occluded patch test or in the ROAT No positive reactions were observed in the control group to any of the test procedures. We concluded that the threshold concentration for occluded patch test to formaldehyde in formaldehyde-sensitive patients was 250 ppm. The threshold in occluded patch test corresponded to the degree of sensitivity Definite positive reactions in the ROAT were not seen, either indicating that they are unlikely to happen with the type of product used or that the exposure time was too short.     

Capsaicin cough sensitivity in allergic asthmatic patients increases during the birch pollen season.

BACKGROUND: A change in neural responsiveness may occur as the result of allergic inflammation in the lower airways as well as in the upper airways. In the lower airways, capsaicin cough sensitivity is known to reflect sensory neural reactivity. OBJECTIVE: The aim of this study was to establish whether allergic inflammation changes airway neural sensory reactivity during prolonged allergen exposure. METHODS: Ten nonsmoking patients with birch pollen-allergic asthma performed a capsaicin inhalation challenge twice, once in the off-pollen season and once during the pollen season. The number of coughs and symptoms induced by capsaicin were recorded and compared with those of healthy control subjects. RESULTS: The response to capsaicin, expressed as number of coughs, increased in a dose-dependent manner during both tests. Before the season, the response was similar to that of healthy control subjects, but during the pollen season, the reactivity was significantly increased. Variations in forced expiratory volume in 1 second were not significant before and after each challenge, and values did not change during the pollen season as compared with the winter season. CONCLUSIONS: Sensory reactivity in allergic asthmatic patients may be increased during prolonged allergen exposure as during the pollen season. This finding suggests that allergic inflammation in the lower and/or upper airways may trigger neurogenic mechanisms of significant clinical importance.