Biomedical subjects

C Lillian Yau

Publications and source records attributed to C Lillian Yau.

8 recordsLinked to original sources

PubMed2005

Increasing trends in elderly persons' use of nonvitamin, nonmineral dietary supplements and concurrent use of medications.

OBJECTIVE: Use of nonvitamin, nonmineral dietary supplements among an elderly cohort was surveyed to determine which were the most frequently used, and to report potential medication/supplement interactions observed. DESIGN: A retrospective review of the use of 22 supplements and prescription/over-the-counter medications was collected annually from 1994 to 1999. SUBJECTS/SETTING: Supplement and medication records for an average of 359 male (36%) and female (64%) participants aged 60 to 99 years were reviewed annually. Ethnic distribution was 91% non-Hispanic white, 7% Hispanic, 1% Asian, and 1% African American. STATISTICAL ANALYSES PERFORMED: Descriptive statistics generated included mean, standard deviation, and frequency by percentage. To compare supplement user and nonsupplement user percentages across age groups, the chi 2 test was used. Linear regression was performed to test for longitudinal usage trends of each individual supplement. RESULTS: By 1999, glucosamine emerged as the most frequently used nonvitamin, nonmineral supplement followed by ginkgo biloba, chondroitin, and garlic. For women, there was a significant linear trend ( P < .05) over time for these 12 supplements: black cohosh, borage, evening primrose, flaxseed oil, chondroitin, dehydroepiandrosterone, garlic, ginkgo biloba, glucosamine, grapeseed extract, hawthorn, and St John's wort. For men, three supplements (alpha lipoic acid, ginkgo biloba, and grape-seed extract) showed a significant linear trend ( P <.05). Potential interactions between supplements and medications were seen for 10 of the 22 supplements surveyed, with a total of 142 potential interactions observed over the 6-year period. CONCLUSIONS: Examining nonvitamin, nonmineral supplement use in combination with prescription/over-the-counter medications in elderly persons is important to identify the potential risks of interactions.

Aged↗

PubMed2005

Determining standards for laparoscopic proficiency using virtual reality.

Laparoscopic training using virtual reality has proven effective, but rates of skill acquisition vary widely. We hypothesize that training to predetermined expert levels may more efficiently establish proficiency. Our purpose was to determine expert levels for performance-based training. Four surgeons established as laparoscopic experts performed 11 repetitions of 12 tasks. One surgeon (EXP-1) had extensive Minimally Invasive Surgical Trainer-Virtual Reality (MIST VR) exposure and formal laparoscopic fellowship training. Trimmed mean scores for each were determined as expert levels. A composite score (EXP-C) was defined as the average of all four expert levels. Thirty-seven surgery residents without prior MIST VR exposure and two research residents with extensive MIST VR exposure completed three repetitions of each task to determine baseline performance. Scores for EXP-1 and EXP-C were plotted against the best score of each participant. On average, the EXP-C level was reached or exceeded by 7 of the 37 (19%) residents. In contrast, the EXP-1 level was reached or exceeded by 1 of 37 (3%) residents and both research residents on all tasks. These data suggest the EXP-C level may be too lenient, whereas the EXP-1 level is more challenging and should result in adequate skill acquisition. Such standards should be further developed and integrated into surgical education.

Clinical Competence↗

PubMed2004

Laparoscopic virtual reality training: are 30 repetitions enough?

BACKGROUND: Current literature suggests that novices reach a plateau after two to seven trials when training on the MIST VR laparoscopic virtual reality system. We hypothesize that significant benefit may be gained through additional training. MATERIALS AND METHODS: Second-year medical students (n = 12) voluntarily enrolled under an IRB-approved protocol for MIST VR training. All subjects completed pre- and posttraining questionnaires and performed 30 repetitions of 12 tasks. Performance data were automatically recorded for each trial. Learning curves for each task were generated by fitting spline curves to the mean overall scores for each repetition. Scores were assessed for plateaus by repeated measures, slope, and best score. RESULTS: On average, subjects completed training in 7.1 h. (range, 5.9-9.2). Two to seven performance plateaus were identified for each of the 12 MIST VR tasks. Initial plateaus were found for all tasks by the 8th repetition; however, ultimate plateaus were not reached until 21-29 repetitions. Overall best score was reached between 20 and 30 repetitions and occurred beyond the ultimate plateau for 9 tasks. CONCLUSIONS: These data indicate that a lengthy learning curve exists for novices and may be seen throughout 30 repetitions and possibly beyond. Performance plateaus may not reliably determine training endpoints. We conclude that a significant and variable amount of training may be required to achieve maximal benefit. Neither a predetermined training duration nor an arbitrary number of repetitions may be adequate to ensure laparoscopic proficiency following simulator training. Standards which define performance-based endpoints should be established.

Adult↗

PubMed2003

Serum insulin concentrations in daily drinkers compared with abstainers in the New Mexico elder health survey.

BACKGROUND: Recent epidemiological studies have shown that individuals who ingest alcohol regularly have a lower prevalence of diabetes mellitus than those who abstain. The purpose of this study was to compare serum glucose and insulin concentrations between daily drinkers and abstainers stratified by diabetic status (participants with diabetes, impaired glucose tolerance, and normal glucose tolerance) to determine if there was a difference in glucose sensitivity (resistance) that might explain the lower prevalence of diabetes in drinkers. METHODS: A cross-sectional community survey was conducted of 883 randomly selected Hispanic and non-Hispanic white men and women, aged >or=65 years, undergoing a home interview and 4-hour interview/examination in a senior health clinic (The New Mexico Elder Health Survey). The interviews included a history of frequency, type, and quantity of alcohol ingested. Serum samples were obtained after an overnight fast and 2 hours after ingestion of 75 grams of glucose for determination of glucose and insulin levels. Height and weight was measured for determination of body mass index. RESULTS: Participants who consumed alcohol daily had significantly lower fasting and 2-hour postglucose serum insulin concentrations compared with those who abstained from alcohol intake, when adjusted using linear logistic regression models for serum glucose concentration, gender, ethnicity, age, and body mass index. CONCLUSIONS: Abstainers with their relative hyperinsulinemia appear to be more insulin resistant than daily moderate drinkers. This difference in insulin sensitivity may explain the lower prevalence of diabetes in drinkers compared with abstainers observed in various epidemiological studies.

Aged↗

PubMed2003

Serum Sex Hormones, IGF-1, and IGFBP3 Exert a Sexually Dimorphic Effect on Lean Body Mass in Aging.

BACKGROUND: Endogenous and exogenous sex hormones affect changes in body composition during aging via independent and dependent effects on the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis and associated binding proteins (BP). METHODS: Fasting serum IGF-1, IGFBP3, testosterone, estrone, and sex hormone binding globulin were analyzed in 48 women on hormone replacement (HRT) (unopposed oral estrogen, HRT+, 74.0 +/- 6 years), 135 women not on HRT (HRT-, 77.3 +/- 7 years), and 128 healthy men (men, ). Total lean body mass (LBM) and total fat were measured by dual energy X-ray absorptiometry. RESULTS: Total LBM decreased with age in all groups (p = .05). LBM was greater, and IGF-1, IGFBP3, and testosterone were lower in HRT+ versus HRT- women (p = .02, p = .01, p = .04, and, respectively). LBM in men was positively related to IGF-1 (p = .02) and testosterone (p < .01), whereas LBM was associated with IGFBP3 (p = .04) and total fat (p < .001) in female HRT+ and total fat (p < .01) in HRT- women. IGF-1 decreased with age in men and HRT- women (p < .01) but did not decrease in HRT+ women. Total fat significantly decreased across age (p < .05). Controlling for age and HRT, the rate of decrease in fat was slower in men versus women (p = .02). IGFBP3 decreased in all groups across age (p < .01), and the ratio of IGF-1 to IGFBP3 decreased faster in men compared to HRT+ and HRT- women (p = .02). CONCLUSIONS: Our data indicate divergent influences of sex steroids, IGF-1, and IGFBP3 on age-related changes in LBM in healthy elderly men and women.

Adipose Tissue↗

PubMed2003

Serum homocysteine concentrations and their relation to serum folate and vitamin B12 concentrations and coronary artery disease prevalence in an urban, bi-ethnic community.

OBJECTIVE: To compare fasting serum total homocysteine (tHcy) concentrations in a randomly selected sample of elderly (> or = 65 years of age) Hispanic and non-Hispanic White (NHW) men and women, to examine associations of tHcy with folate and vitamin B12, and then to correlate these with the prevalence of coronary heart disease (CHD) in these 4 ethnic/ gender groups. DESIGN AND PARTICIPANTS: Equal numbers of Hispanic and NHW men and women were randomly selected from the Healthcare Financing Administration (Medicare) registrant list for Bernalillo County (Albuquerque), New Mexico, and asked to volunteer for a paid home interview, to be followed by a paid, comprehensive interview/examination covering health and health-related issues. INTERVENTIONS AND MAIN OUTCOME MEASURES: Serum concentrations of tHcy, folate, and vitamin B12 were determined and correlated with the prevalence of CHD, after adjusting for other CHD risk factors (age, diabetes, hypertension, smoking, dyslipidemia, adiposity). RESULTS: Men and Hispanics had higher serum tHcy concentrations compared to women and non-Hispanic Whites (NHWs), respectively. After adjusting for lower concentrations of serum folate and vitamin B12 in Hispanics, the differences between Hispanics and NHWs were no longer significant. There was a direct association between serum tHcy concentrations and the prevalence of CHD after adjusting for other known risk factors that was most significant in Hispanic women. CONCLUSIONS: The higher serum tHcy concentrations observed in Hispanics compared to NHWs can be explained by lower levels of serum folate and vitamin B12. A direct association between serum tHcy concentrations and prevalence of CHD was observed primarily in women, and was most significant in Hispanic women.

Aged↗

PubMed2002

Analysis of censored and incomplete survival data using flowgraph models.

Multi-state stochastic models are widely used to model stages of disease progression in survival analysis. This paper develops flowgraph models for data analysis in survival analysis. We illustrate these methods using data from a study of diabetic retinopathy consisting of 277 subjects with insulin-dependent (type I) diabetes mellitus (IDDM). These data were collected at the Eye-Kidney Clinic of the Barbara Davis Center for Childhood Diabetes at the University of Colorado Health Sciences Center.

Computer Simulation↗

PubMed2002

Nightmare frequency in sexual assault survivors with PTSD.

Sexual assault survivors with post-traumatic stress disorder (PTSD) were assessed for frequency of nightmares, measured retrospectively on the Nightmare Frequency Questionnaire (NFQ) and prospectively on nightmare dream logs (NLOG). Retrospective frequency was extremely high, averaging occurrences every other night and an estimated number of nightmares greater than five per week. Test-retest reliability data on the NFQ yielded weighted kappa coefficients of .85 (95% CI, .74-.95) for nights and .90 (95% CI, .83-.97) for nightmares. Correlations between retrospective and prospective nightmare frequencies ranged between .53 (P = .001) for nights and .63 (P = .001) for nightmares. Correlations between frequency and distress measures (anxiety, depression, post-traumatic stress) yielded coefficients ranging from (r = .28-.53). Compared with intrusive, cumbersome and time-consuming prospective measurements, the NFQ appears reliable, convenient, and equally useful in assessing nightmare frequency in a group of sexual assault survivors. Nightmare frequency, prevalence, distress and impairment are discussed.

Adult↗