Oolong tea does not improve glucose metabolism in non-diabetic adults.

BACKGROUND: Studies of the influence of tea on glucose metabolism have produced inconsistent results, possibly because of the lack of dietary control and/or unclear characterization of tea products. METHODS: Therefore, a double-blind crossover study was conducted in which healthy males (n = 19) consumed each of three oolong tea products or a control beverage as part of a controlled diet. Treatment beverages (1.4 l/day) were consumed for 5 days, followed by assessment of fasting plasma glucose, fasting serum insulin and an oral glucose tolerance test. Tea products included oolong tea, oolong tea with added catechins and oolong tea with added oolong tea polyphenols, and control beverages included caffeinated water and unsupplemented water. On the fifth day of each treatment period, treatment beverages were consumed with a standardized meal, and glucose and insulin responses were assessed for 240 min. RESULTS: No significant differences were detected for fasting plasma glucose, fasting serum insulin, incremental plasma glucose area under the concentration time curve (AUC), total plasma glucose AUC or total serum insulin AUC. CONCLUSIONS: Neither oolong tea nor oolong tea supplemented with catechins or other polyphenols produced improved glucose metabolism in healthy adult volunteers on the basis of this highly controlled dietary intervention trial.

Incidence and effects of Ha-ras codon 12 G-->A transition mutations in preneoplastic lesions induced by N-nitrosomethylbenzylamine in the rat esophagus.

N-nitrosomethylbenzylamine (NMBA)-induced rat esophageal tumorigenesis is an important model for squamous cell carcinoma of the human esophagus. In this model, previous studies have shown that the GGA-->GAA Ha-ras codon 12 mutation is present in the majority of papillomas. No other Ha-ras mutation has been identified. Studies using other models of chemical carcinogenesis suggest that Ha-ras activation has a critical role during tumor initiation. We have used laser-capture microdissection and polymerase chain reaction-restriction fragment length polymorphism analysis to study the role of codon 12 Ha-ras mutation at various stages of tumor development in the rat esophagus. Our results indicate that Ha-ras mutation was present infrequently (4.3%) in premalignant lesions. The incidence of Ha-ras mutation was high in papillomas (57.1%), however, and 50% of papillomas expressed mutant Ha-ras RNA message. Additionally, there was a linear trend correlating increased incidence of Ha-ras mutation with later papilloma stage. These data suggest the role of ras activation later in neoplastic development. To evaluate the potential mechanism of action by which Ha-ras contributes to promotion and progression in this model, we compared mRNA expression of cyclin D1 and p27 in Ha-ras mutant and Ha-ras normal papillomas. We found no differences in mRNA expression of either cyclin D1 or p27 between these two papilloma populations. Our data suggest an important paradigm shift for the role of ras mutations in this model of chemical carcinogenesis, indicating a functional role of Ha-ras activation in promotion/progression and not in the initiation phase of NMBA-induced papillomagenesis.

Effects of lyophilized black raspberries on azoxymethane-induced colon cancer and 8-hydroxy-2'-deoxyguanosine levels in the Fischer 344 rat.

This study examined the effects of lyophilized black raspberries (BRB) on azoxymethane (AOM)-induced aberrant crypt foci (ACF), colon tumors, and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in male Fischer 344 rats. AOM was injected (15 mg/kg body wt i.p.) once per week for 2 wk. At 24 h after the final injection, AOM-treated rats began consuming diets containing 0%, 2.5%, 5%, or 10% (wt/wt) BRB. Vehicle controls received 5% BRB or diet only. Rats were sacrificed after 9 and 33 wk of BRB feeding for ACF enumeration and tumor analysis. ACF multiplicity decreased 36%, 24%, and 21% (P < 0.01 for all groups) in the 2.5%, 5%, and 10% BRB groups, respectively, relative to the AOM-only group. Total tumor multiplicity declined 42%, 45%, and 71% (P < 0.05 for all groups). Although not significant, a decrease in tumor burden (28%, 42%, and 75%) was observed in all BRB groups. Adenocarcinoma multiplicity decreased 28%, 35%, and 80% (P < 0.01) in the same treatment groups. Urinary 8-OHdG levels were reduced by 73%, 81%, and 83% (P < 0.01 for all groups). These results indicate that BRB inhibit several measures of AOM-induced colon carcinogenesis and modulate an important marker of oxidative stress in the Fischer 344 rat.

Nocardiosis: a literature review and a case report of Nocardia asteroides infection.

Increased chemotherapy and longterm steroid treatments have made nocardiosis a prevalent problem in the United States. The most common infectant is the bacterium Nocardia asteroides. Culturing and identifying the organism and the diagnosis and treatment of the disease are discussed. A literature review and a related case history accompany the discussion.