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The ABCB1 gene, coding for the efflux transporter P-glycoprotein (PGP), is a candidate gene for Alzheimer disease (AD). P-glycoprotein is heavily expressed at the blood-brain barrier, where it mediates the efflux of β-amyloid (Aβ) from the brain. In this study, we investigated a possible association between 2 common ABCB1 polymorphisms, G2677T/A (Ala893Ser/Thr) and C3435T, AD, and cerebrospinal fluid (CSF) levels of Aβ. No strong evidence for association was found. [ABSTRACT FROM AUTHOR]

Background: We evaluate the performance of ovulation detection methods and present new approaches, including evaluation of methods for precision, combining multiple markers into a hierarchical system and using ovulation markers in intermittent sampling designs., Methods: With serum LH peak day as the 'gold standard' of ovulation, we estimated accuracy and precision of ovulation day algorithms using 30 ovulatory menstrual cycles with daily urinary and serum hormones and transvaginal ultrasound. Sensitivity and specificity for estimating the presence of ovulation were tested using visually assessed ovulatory (30) and anovulatory (22) cycles., Results: Sensitivity and specificity ranged from 70 to 100% for estimating presence of ovulation with twice-per-cycle, weekly, twice weekly, every-other-day and daily specimens. A combined hierarchical method estimated ovulation day using daily specimens within +/-2 days of the gold standard in 93% of cases. Accuracy of estimating ovulation day within +/-2 days using intermittent sampling ranged from 40% (weekly sampling) to 97% (every-other-day)., Conclusions: A combined hierarchical algorithm using precise and accurate markers allows maximal use of available data for efficient and objective identification of ovulation using daily specimens. In intermittent sampling designs, the presence and the timing of ovulation can be estimated with good sensitivity, specificity and accuracy.

Background: Despite having lower average body mass indexes (BMIs) than do whites, Asians are at high risk of type 2 diabetes, possibly because of their greater central adiposity. The criteria for identifying individuals at risk of obesity-related conditions are usually not population specific., Objective: Our goal was to determine whether the National Heart, Lung, and Blood Institute (NHLBI) overweight and obesity guidelines are useful for identifying diabetes risk in Japanese Americans., Design: This was a prospective, cohort study of 466 nondiabetic Japanese Americans [age: 52.2 +/- 0.6 y; BMI (in kg/m(2)): 24.1 +/- 0.2; +/- SEM]. Diabetes status at a 5-y follow-up visit was assessed with an oral-glucose-tolerance test., Results: Among 240 subjects aged < or = 55 y, incident diabetes was strongly associated with overweight (BMI > or = 25) at baseline [relative risk (RR): 22.4; 95% CI: 2.7, 183; adjusted for age, sex, smoking, and family history] and weight gain of > 10 kg since the age of 20 y (adjusted RR: 4.5; 95% CI: 1.4, 14.5). NHLBI definitions of central obesity (waist circumference > or = 88 cm for women and > or = 102 cm for men) were unsuitable for this population because only 15 of 240 subjects met these criteria. A waist circumference greater than or equal to the third tertile was associated with diabetes (adjusted RR: 5.4; 95% CI: 1.7, 17.0). Among 226 subjects aged >55 y, incident diabetes was not associated with BMI, weight gain, or waist circumference., Conclusions: NHLBI definitions are useful for identifying overweight Japanese Americans aged < 55 y who are at high risk of diabetes. Although central adiposity is an important risk factor, the guidelines for waist circumference are insensitive predictors of diabetes risk in this population.

This is a review of research carried out in Japanese Americans that points towards possible approaches to prevention of type 2 diabetes mellitus. The natural history of type 2 diabetes usually includes both insulin resistance and beta-cell dysfunction. Insulin secretion may compensate for insulin resistance. Alternatively, enhanced insulin sensitivity may mask an insulin secretory defect. Epidemiological data support the view that in the vast majority of cases of type 2 diabetes, insulin resistance is essential to the pathogenesis of hyperglycemia. Increased diabetes prevalence as ethnic groups migrate to more urban or westernized regions has been attributed to increased occurrence of insulin resistance. Research among Japanese Americans in Seattle, Washington, showed a higher prevalence of type 2 diabetes than in Japan, which suggested that factors associated with 'westernization' might be playing a role in bringing out underlying susceptibility to diabetes. Our research has shown that these impressions were correct and that the abnormalities that characterize the metabolic syndrome play a significant role. Due to increased intra-abdominal fat deposition, Japanese Americans were likely to be 'metabolically obese' despite relatively normal BMI. A diet higher in animal fat and lower levels of physical activity were risk factors leading to increased intra-abdominal fat deposition, insulin resistance, and diabetes. Information from epidemiological studies such as these may be used to determine whether diabetes may be prevented through changes in lifestyle or application of specific therapies targeted towards identified metabolic abnormalities.