Klebsiella pneumoniae RS-13 and Acetobacter liquefaciens S-1, both methyl red (MR)-degrading bacterial strains, degraded N,N'-dimethyl-p-phenylenediamine (DMPD) under aerobic conditions. DMPD, a toxic and mutagenic aromatic amine, is formed during the reductive cleavage of azo dyes such as MR. The effects of physical parameters, such as temperature and aeration, and chemical parameters, such as pH and concentrations of glucose, ethanol and ammonium sulphate in the culture medium, on the degradation of DMPD by these bacteria were determined. Klebsiella pneumoniae RS-13 degraded DMPD more efficiently than A. liquefaciens S-1 under all physicochemical conditions, except in the presence of ethanol as carbon and energy sources. In addition, Kl. pneumoniae RS-13 degraded DMPD at low levels of carbon and nitrogen at pH 6-8. These results indicate that it is feasible to use Kl. pneumoniae RS-13 to completely degrade the detoxify MR under aerobic conditions.
The sunlight exposure questionnaire for use in the Chinese population was constructed based on extensive literature review and item suitability for measuring life-time exposure. The content validity index (CVI) was derived from ratings by, an expert panel to assess the item content and relevance. 650 population-based Chinese women completed the sunlight exposure questionnaire through telephone interview. To assess the questionnaire reliability, 94 women were re-interviewed after 2 weeks. 98.4% of the sunlight exposure questionnaire items were found to have valid CVI (>0.83). The Scree plot and the Principal Components Factor Analysis showed a two-factor construct was appropriate and no questionnaire item needed to be excluded. The questionnaire also had a good test-retest reliability (ICC: 0.59–0.93; k: 0.51–100). This sunlight exposure questionnaire was found to be adequate for measurement of life-time sunlight exposure among Hong Kong Chinese women.
PurposeThis study aims to assess the association of sunlight exposure with breast cancer risk, measured by the breast density assessed from Tabár's mammographic pattern in Chinese women.MethodsA total of 676 premenopausal women were recruited to participate in this study, in which 650 completed a validated sunlight exposure questionnaire via telephone. The mammograms were classified according to Tabár's classification for parenchyma, and patterns IV & V and I, II & III indicated respectively high and low risk mammographic patterns for breast cancer. The odds ratios (OR) and 95% confidence intervals (CIs) for sun exposure-related variables were estimated using unconditional logistic regression with adjustment for potential confounders.ResultsAmong 646 participants, women with high breast cancer risk (Tabár's patterns IV &V) had less hours spent in the sun than those with low risk (I, II & III) at any age stage. A higher level of sunlight exposure was associated with a significantly lower risk having high risk Tabár's pattern. Women aged 40 to 44 years who were in the highest tertile of lifetime total hours spent in the sun had a multi-adjusted OR of 0.41 (95% CI, 0.18-0.92; p for trend=0.03) compared with those in the lowest tertile (>2.19 hr/day vs. <1.32 hr/day). For hours spent in the sun across the ages of 6 to 12 years, the comparable OR was 0.37 (95% CI, 0.15-0.91; p for trend=0.03).ConclusionThese findings suggest that higher sunlight exposure is related to a lower risk of having high risk breast density pattern in premenopausal women. Our results also suggest the most relevant period of exposure is during earlier life.
The fibrinolytic activity of 156 malignant and 36 benign solid tumors from autopsy and biopsy specimens was studied by the fibrin slide technique. The inhibitory activity against fibrinolysis was graded according to the lysis time of vascular tissues within the tumor. The results show that all malignant solid tumors, with the exception of prostate carcinoma, demonstrated varying degrees of inhibition of fibrinolysis. Persistently high inhibitory activity was found in squamous cell carcinoma of the esophagus, the respiratory tract, cervix uteri, and skin; carcinoma of uterus; colorectal carcinoma; small cell anaplastic carcinoma of lung; neuroblastoma, carcinoma of bile duct, while malignant tumors of the kidney show a lesser degree of inhibition. In contrast, with the exception of the hydatidiform mole, benign solid tumors show little or no inhibition. A similar absence of fibrinolytic activity is seen in metastatic disease. Further studies of the role of the fibrinolytic system in tumors seems warranted.
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