Optokinetic nystagmus,vection, and motion sickness

BACKGROUND: Two current theories concerning the etiology of motion sickness (MS)-the eye movement hypothesis and sensory conflict theory-were evaluated under conditions that manipulated the degree of optokinetic nystagmus (OKN) and/or vection. METHOD: Eye movement and perceptual responses were elicited with whole field stimulation in a vertically striped rotating drum and modulated with fixation and/or a restriction of the field of view (FOV). Measures of OKN, vection, and MS were recorded under the various conditions. RESULTS: Both visual field restriction and/or fixation diminished circular vection, OKN, and MS. Conditions involving both fixation and restricted FOV resulted in greater reductions in MS than did either restriction alone. CONCLUSIONS: These findings lend support to a multi-factor explanation of MS, involving both sensory conflict and eye movement.     

Expression of bone morphogenetic protein receptors type-IA, -IB and -II correlates with tumor grade in human prostate cancer tissues

Bone morphogenetic proteins (BMPs) are potential regulators of prostate cancer cell growth and metastasis that signal through an interaction with BMP membrane receptors (BMPRs) type I and type II. In the present study, Western blot and immunohistochemical analysis of BMPRs were carried out in benign and malignant human prostate tissues to explain the loss of BMP response in human prostate cancer cells. The results demonstrated that the benign prostate specimens expressed high levels of all three BMPRs. In normal prostate, BMPRs were localized predominantly to epithelial cells. Among prostate cancer specimens, well-differentiated cancers were positive for the expression of BMPR-II, BMPR-IA, and BMPR-IB, for the most part. In contrast, only 1 of 10 poorly differentiated prostate cancer cases was positive for each of the three BMPRs (P < 0.005 for all three receptors). Taken together, these results indicate that human prostate cancer cells frequently exhibit loss of expression of BMPRs and suggest that loss of BMPRs may play an important role during the progression of prostate cancer.     

Life Stage,Alcohol Consumption Patterns,Alcohol-Related Consequences,and Gender

This paper presents findings from a European collaborative study. A common framework for reanalysis of existing data was devised. Alcohol-related problems encountered were classified as internal and external. Logistic regression analyses were then conducted to predict lifetime presence of any internal problem, any external problem, and any problem at all. The predictor variables were gender, life stage (corresponding roughly to young, middle and older age), past year's drinking level in four categories of grams of alcohol per month, and past year's binge drinking. All four predictor variables were associated with the presence of alcohol-related problems, with women and retired people having fewer problems and heavy drinkers and binge drinkers having more. At all levels of alcohol consumption, men were more likely than women to experience at least one adverse consequence. Internal problems were more common than external problems. Country differences are discussed and recommendations are made for further studies.     

Survey nonresponse bias among young adults: the role of alcohol, tobacco, and drugs

The purpose of this study is to determine the role of alcohol, tobacco, and drug use as predictors of survey panel attrition among an occupational cohort of young adults in the U.S. military. Baseline data on substance use and sociodemographic factors were obtained from 2838 men and women through confidential, self-administered questionnaires while they attended Navy basic training or Officer Candidate School in 1998. Longitudinal follow-up using mailed self-administered questionnaires was begun in 2000. Multivariate logistic regression models were developed to estimate the odds of attrition in relation to baseline substance use. Results revealed that tobacco use was a significant predictor of attrition [Odds ratio (OR) = 1.63; 95% Confidence Interval (CI): 1.37, 1.95]. A significant interaction between level of education and drug use indicated that respondents with less than a college education who were also drug users were at elevated risk for attrition (OR = 2.39; 95% CI 1.09, 5.28). Other significant predictors of panel attrition were male gender and younger age. Alcohol use was not significantly associated with attrition. The findings suggest that tobacco users and drug users with less than a college education may be an important source of nonresponse bias in longitudinal surveys of employed young adults.     

Proximal femur bone geometry is appropriately adapted to lean mass in overweight children and adolescents

It is unclear if the bones of overweight children are appropriately adapted to increased loads. The objective of this study was to compare bone geometry in 40 overweight (body mass index [BMI] > 85th percentile) and 94 healthy weight (BMI < or = 85th percentile) subjects, ages 4-20 years. Dual energy X-ray absorptiometry (Hologic QDR 2000) scans were analyzed at the femoral shaft (FS) and narrow neck (NN) by the Hip Structure Analysis program. Subperiosteal width, cortical thickness and indices of bone axial and bending strength (bone cross-sectional area [CSA] and section modulus [Z]) were measured from bone mass profiles. Multivariate regression models were used to compare overweight and healthy weight subjects. Z was 11 (95% CI 5, 19) and 13 (7, 20) percent higher at the FS and NN, respectively, in overweight subjects (P < 0.001), adjusted for height, maturation and gender. At the NN, higher Z was due to greater subperiosteal width [4% (2, 7)] and bone CSA [10% (5, 16]) and at the FS, to higher bone CSA [10% (5, 16)] and thicker cortices [9% (3, 15)]. When lean mass was added to the models, bone variables did not differ between overweight and healthy weight subjects (P > 0.22), with the exception of NN subperiosteal width [3% (0, 6), P = 0.04]. Fat mass did not contribute significantly to any model. In summary, proximal femur bone geometric strength in overweight children was appropriately adapted to lean mass and height but greater weight in the form of fat mass did not have an independent effect on bone bending strength. These geometric adaptations are consistent with the mechanostat hypothesis that bone strength adapts primarily to muscle forces, not to static loads represented by body weight.