Hydroxyl radical (OH) is an important oxidant in atmospheric aqueous phases such as cloud and fog drops and water-containing aerosol particles. We find that numerical models nearly always overestimate aqueous hydroxyl radical concentrations because they overpredict its rate of formation and, more significantly, underpredict its sinks. To address this latter point, we examined OH sinks in atmospheric drops and aqueous particles using both new samples and an analysis of published data. Although the molecular composition of organic carbon, the dominant sink of OH, is extremely complex and poorly constrained, this sink behaves very similarly in different atmospheric waters and even in surface waters. Thus, the sink for aqueous OH can be estimated as the concentration of dissolved organic carbon multiplied by a general scavenging rate constant [kC,OH = (3.8 ± 1.9) × 10(8) L (mol C)(-1) s(-1)], a simple process that should significantly improve estimates of OH concentrations in atmospheric drops and aqueous particles.
Plasma vitamin E levels were significantly lower in patients with active variant angina than in subjects without coronary spasm, suggesting an association between vitamin E deficiency and coronary artery spasm.
Previous research has shown that hesperidin, a flavanone glycoside in orange juice, inhibits colon carcinogenesis and that feeding double-strength orange juice delays the onset of chemically induced mammary cancer in rats. This study determined whether feeding single-strength, pasteurized orange juice would inhibit azoxymethane (AOM)-induced colon cancer in male Fischer 344 rats. Colon cancer was initiated by injecting AOM (15 mg/kg body wt) at 22 and 29 days of age. One week after the second AOM injection, orange juice replaced drinking water for the experimental group (n = 30). The rats were killed 28 weeks later, and tumors were removed for histological analysis. Feeding orange juice reduced tumor incidence by 22% (p < 0.05). Tumor reduction was associated with a decreased labeling index and proliferation zone in the colonic mucosa. Hesperidin, other flavonoids, limonin 17-beta-D-glucopyranoside, and other limonoid glucosides are potential chemopreventive agents in orange juice that could account for the decreased colon tumorigenesis associated with feeding orange juice.
The present study was designed to examine the distribution of hepatitis B virus (HBV) genotypes among patients at various stages of chronic liver disease type B in Okinawa Prefecture, Japan, where the prevalence of hepatitis B surface antigen is the highest in Japan despite the lowest mortality rate from primary liver cancer. Serum samples from 227 HBV carriers were determined for HBV genotype by polymerase chain reaction (PCR)-restriction fragment length polymorphism. Five of 227 sera were negative for HBV DNA by nested PCR and were excluded from the genotype analysis. Genotype B was predominant in asymptomatic carriers (45/67, 67%), whereas genotype C was predominant in chronic liver disease: 49% (50/103) in patients with chronic hepatitis, 63% (20/32) in patients with cirrhosis, and 60% (12/20) in patients with hepatocellular carcinoma. The distribution of genotype B decreased with increasing liver disease severity. However, this tendency was seen among patients aged less than 50 years old, whereas the prevalence of genotype B was similar among carriers with various liver diseases who were older than age 50. In conclusion, HBV genotype B was prevalent and less frequent among patients with advanced liver disease, particularly in patients aged less than 50 years. These findings suggest that the preponderance of genotype B is responsible for the low mortality rate of primary liver cancer associated with HBV seen in Okinawa Prefecture, despite having the highest HBV carrier rate in Japanese.
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