The association between driving time and unhealthy lifestyles: a cross-sectional, general population study of 386 493 UK Biobank participants.

BACKGROUND: Driving is a common type of sedentary behaviour; an independent risk factor for poor health. The study explores whether driving is also associated with other unhealthy lifestyle factors. METHODS: In a cross-sectional study of UK Biobank participants, driving time was treated as an ordinal variable and other lifestyle factors dichotomized into low/high risk based on guidelines. The associations were explored using chi-square tests for trend and binary logistic regression. RESULTS: Of the 386 493 participants who drove, 153 717 (39.8%) drove <1 h/day; 140 140 (36.3%) 1 h/day; 60 973 (15.8%) 2 h/day; and 31 663 (8.2%) ≥3 h/day. Following adjustment for potential confounders, driving ≥3 h/day was associated with being overweight/obese (OR = 1.74, 95% CI: 1.64-1.85), smoking (OR = 1.48, 95% CI: 1.37-1.63), insufficient sleep (1.70, 95% CI: 1.61-1.80), low fruit/vegetable intake (OR = 1.26, 95% CI: 1.18-1.35) and low physical activity (OR = 1.05, 95% CI: 1.00-1.11), with dose relationships for the first three, but was not associated with higher alcohol consumption (OR = 0.94, 95% CI: 0.87-1.02). CONCLUSIONS: Sedentary behaviour, such as driving, is known to have an independent association with adverse health outcomes. It may have additional impact mediated through its effect on other aspects of lifestyle. People with long driving times are at higher risk and might benefit from targeted interventions.

Adiposity among 132 479 UK Biobank participants; contribution of sugar intake vs other macronutrients.

Background: Policy makers are being encouraged to specifically target sugar intake in order to combat obesity. We examined the extent to which sugar, relative to other macronutrients, was associated with adiposity. Methods: We used baseline data from UK Biobank to examine the associations between energy intake (total and individual macronutrients) and adiposity [body mass index (BMI), percentage body fat and waist circumference]. Linear regression models were conducted univariately and adjusted for age, sex, ethnicity and physical activity. Results: Among 132 479 participants, 66.3% of men and 51.8% of women were overweight/obese. There was a weak correlation (r = 0.24) between energy from sugar and fat; 13% of those in the highest quintile for sugar were in the lowest for fat, and vice versa. Compared with normal BMI, obese participants had 11.5% higher total energy intake and 14.6%, 13.8%, 9.5% and 4.7% higher intake from fat, protein, starch and sugar, respectively. Hence, the proportion of energy derived from fat was higher (34.3% vs 33.4%, P < 0.001) but from sugar was lower (22.0% vs 23.4%, P < 0.001). BMI was more strongly associated with total energy [coefficient 2.47, 95% confidence interval (CI) 2.36-2.55] and energy from fat (coefficient 1.96, 95% CI 1.91-2.06) than sugar (coefficient 0.48, 95% CI 0.41-0.55). The latter became negative after adjustment for total energy. Conclusions: Fat is the largest contributor to overall energy. The proportion of energy from fat in the diet, but not sugar, is higher among overweight/obese individuals. Focusing public health messages on sugar may mislead on the need to reduce fat and overall energy consumption.

Exposure to tobacco smoke in utero or during early childhood and risk of hypomania: Prospective birth cohort study.

OBJECTIVES: Using data from a prospective birth cohort, we aimed to test for an association between exposure to tobacco smoke in utero or during early development and the experience of hypomania assessed in young adulthood. METHODS: We used data on 2957 participants from a large birth cohort (Avon longitudinal study of parents and children [ALSPAC]). The primary outcome of interest was hypomania, and the secondary outcome was "hypomania plus previous psychotic experiences (PE)". Maternally-reported smoking during pregnancy, paternal smoking and exposure to environmental tobacco smoke (ETS) in childhood were the exposures of interest. Multivariable logistic regression was used and estimates of association were adjusted for socio-economic, lifestyle and obstetric factors. RESULTS: There was weak evidence of an association between exposure to maternal smoking in utero and lifetime hypomania. However, there was a strong association of maternal smoking during pregnancy within the sub-group of individuals with hypomania who had also experienced psychotic symptoms (OR=3.45; 95% CI: 1.49-7.98; P=0.004). There was no association between paternal smoking, or exposure to ETS during childhood, and hypomania outcomes. CONCLUSIONS: Exposure to smoking in utero may be a risk factor for more severe forms of psychopathology on the mood-psychosis spectrum, rather than DSM-defined bipolar disorder.

Motion-guided attention promotes adaptive communications during social navigation.

Animals are capable of enhanced decision making through cooperation, whereby accurate decisions can occur quickly through decentralized consensus. These interactions often depend upon reliable social cues, which can result in highly coordinated activities in uncertain environments. Yet information within a crowd may be lost in translation, generating confusion and enhancing individual risk. As quantitative data detailing animal social interactions accumulate, the mechanisms enabling individuals to rapidly and accurately process competing social cues remain unresolved. Here, we model how motion-guided attention influences the exchange of visual information during social navigation. We also compare the performance of this mechanism to the hypothesis that robust social coordination requires individuals to numerically limit their attention to a set of n-nearest neighbours. While we find that such numerically limited attention does not generate robust social navigation across ecological contexts, several notable qualities arise from selective attention to motion cues. First, individuals can instantly become a local information hub when startled into action, without requiring changes in neighbour attention level. Second, individuals can circumvent speed-accuracy trade-offs by tuning their motion thresholds. In turn, these properties enable groups to collectively dampen or amplify social information. Lastly, the minority required to sway a group's short-term directional decisions can change substantially with social context. Our findings suggest that motion-guided attention is a fundamental and efficient mechanism underlying collaborative decision making during social navigation.

Calcium intakes and femoral and lumbar bone density of elderly U.S. men and women: National Health and Nutrition Examination Survey 2005-2006 analysis.

OBJECTIVES: This analysis was aimed at assessing the benefits of total calcium intake from diet and supplements on both femoral neck and lumbar vertebral bone mineral density (BMD) in a representative sample of older U.S. women and men. DESIGN: For 1384 women and men aged 50-70 and 71+ yr, quintiles of total calcium intake were tested for their association with hip and spine BMD after adjusting for body mass index. All data in this observational study were cross-sectional. DATA SOURCE: Subjects included elderly residents statistically representative of the United States, women and men aged 50 yr and older in the National Health and Nutrition Examination Survey 2005-2006 cohort. MAIN OUTCOME MEASURES: Calcium intakes and femoral and lumbar BMD were evaluated. RESULTS: Total calcium intakes ranged from means of 400+ mg/d in quintile 1 to 2100+ in quintile 5. Little difference in hip or lumbar BMD was found in relation to total calcium consumption in women and men across five quintiles, especially for those aged 50-70, in models adjusted for body mass index only. Femoral hip BMD in men 71 and older increased slightly with high calcium intake (3.6% higher density, P = 0.0391), whereas femoral BMD in women 71 and older decreased slightly with high calcium intake (-3.2%, P = 0.0132). Lumbar BMD remained fairly consistent across all quintiles, but greater variation within each quintile was found compared with the hip. CONCLUSIONS: A usual high calcium intake beyond the recommended dietary allowance of elderly women and men, most commonly achieved by calcium supplements, did not provide any benefit for hip or lumbar BMD. A dietary intake of calcium approaching or meeting the current recommendations was not related to higher BMD of the hip or lumbar spine in late life compared with lower intakes of calcium in older adults.

Collective motion in animal groups from a neurobiological perspective: the adaptive benefits of dynamic sensory loads and selective attention.

We explore mechanisms associated with collective animal motion by drawing on the neurobiological bases of sensory information processing and decision-making. The model uses simplified retinal processes to translate neighbor movement patterns into information through spatial signal integration and threshold responses. The structure provides a mechanism by which individuals can vary their sets of influential neighbors, a measure of an individual's sensory load. Sensory loads are correlated with group order and density, and we discuss their adaptive values in an ecological context. The model also provides a mechanism by which group members can identify, and rapidly respond to, novel visual stimuli.

Micronutrient intakes in two US populations of older adults: lipid research clinics program prevalence study findings.

Dietary intakes of several minerals and vitamins were assessed in two US sub-populations of older men and women between 60 and 80 years as part of the Lipid Research Clinics Program Prevalence Study conducted in the mid-1980s prior to widespread fortification. Dietary intakes were analyzed from 24-hour recalls using the Minnesota Nutrition Coding Center. Descriptive statistics on the two diverse sub-populations were generated for the elderly subjects at the two clinic sites, southern California and Oklahoma. Regression analyses of specific micronutrients were performed while controlling for several variables, namely, age, sex, clinic (region), education, Body Mass Index (BMI), alcohol consumption, and smoking status. Compared to current (1999-2004) Estimated Average Requirements (EARs) and Adequate Intakes (AIs) for three micronutrients without EARs for the US and Canada, several micronutrients were consumed at or close to their EAR values. Exceptions include intakes of vitamin A, vitamin E, folic acid, potassium and calcium which were very low; intakes of thiamin, riboflavin, niacin, and vitamin C were low but closer to the published EAR or AI values. High intakes approaching cut-offs for practically all subjects were found for both groups of elders at the two clinic sites for iron, phosphorus, and sodium. In general, California elderly had somewhat better consumption patterns for the vitamins, but the Oklahomans, males at least, had higher overall mineral intakes. The micronutrient deficits found in this small study suggest that most elderly US citizens were likely to be deficient in five micronutrients and marginally insufficient in four others in the mid-1980s and, despite even greater fortification currently, elderly intakes seem not to have improved substantially since the 1980s, except for subjects who are regular multi-supplement users.

Studies on the pharmacokinetics and metabolism of a gamma-secretase inhibitor BMS-299897, and exploratory investigation of CYP enzyme induction.

BMS-299897 is a gamma-secretase inhibitor that was effective in reducing amyloid beta-peptide (A beta) in transgenic mice and guinea pigs. Therefore, pharmacokinetic and drug metabolism studies were conducted in animals to support its clinical development. The compound appeared to have low to intermediate total body clearance and was orally bioavailable (24-100%). The oral absorption of BMS-299897 from solid dosage forms appeared to be dissolution rate-limited. BMS-299897 was distributed into extravascular space (V(ss) >or= 1.3 l kg(-1)), including brain (brain-to-plasma ratio = 0.13-0.50). BMS-299897 appeared to be a P-glycoprotein (P-gp) substrate as the brain-to-plasma ratio was two-fold higher in the mdr1a knockout mouse as compared with the wild-type. Apparent autoinduction by BMS-299897 was observed in murine and rat efficacy and toxicity studies. In vitro, BMS-299897 was a weaker inducer of cytochrome P450 3A4 (CYP3A4) and a weaker transactivator of human pregnane X receptor (hPXR) as compared with rifampicin. Induction of human UGT1A and UGT2B was evaluated in primary human hepatocytes, but the results were inconclusive. A low potential for autoinduction in humans was predicted at a clinical dose of 250 mg and the prediction was consistent with the findings from a clinical multiple-dose study with BMS-299897 in probable Alzheimer's patients.

Effects of systemic administration of mirtazapine on respiratory muscle activity in sleeping rats.

Mirtazapine (MIRT) is an antidepressant with mixed noradrenergic and serotonergic effects in central nervous system. The present study was undertaken to assess whether MIRT can stimulate genioglossus muscle (GG) activity in the conscious, behaving rat. Nine male rats were chronically instrumented with GG and neck muscle EMG electrodes. EEG electrodes were implanted to acquire sleep stage. Results demonstrated a dose-dependent effect of MIRT on GG activity during sleep, although no changes reached statistical significance. Low dose MIRT (0.1 mg/kg) showed a slight increase in GG phasic activity. In contrast, higher doses of MIRT (0.5-1.0 mg/kg) tended to decrease GG activity relative to vehicle, in addition to decreasing total sleep time.

The predictive value of p53 and p33(ING1b) in patients with Dukes'C colorectal cancer.

OBJECTIVE: Identification of biological markers that may predict response to chemotherapy would allow the individualization of treatment by enabling selection of patients most likely to benefit from chemotherapy. The aims of this study were to determine whether p53 mutation status and p53 and p33(ING1b) protein expression can predict which patients with Dukes' C colorectal cancer following curative surgical resection respond to adjuvant chemotherapy with 5-fluorouracil (5-FU). METHOD: Patients with Dukes'C colorectal cancer (n = 41) were studied. DNA was extracted and analysed for p53 mutation using PCR-based direct DNA sequencing. Tumours were analysed for p53 protein expression by immunohistochemistry using DO-7 monoclonal antibody and for p33(ING1b) protein expression using GN1 monoclonal antibody. RESULTS: There was a significant association between p53 mutation status analysed by gene sequencing and overall and metastasis-free survival (P = 0.03 and 0.004, respectively, log-rank test). By contrast, no significant correlation was found between p53 and p33(ING1b) protein expression and overall or metastasis-free survival. CONCLUSION: In patients with Dukes'C colorectal cancer who underwent curative surgical resection of the primary tumour, followed by 5-FU-based adjuvant chemotherapy, p53 mutation status as assessed by gene sequencing is a significant predictor of overall and metastasis-free survival.

A comparison of CFU-GM, BFU-E and endothelial progenitor cells using ex vivo expansion of selected cord blood CD133(+) and CD34(+) cells.

BACKGROUND: CD133 is a newly developed hematopoietic stem cell marker but little is known about its function. Whether CD133(+) cell selection provides any advantage over CD34(+) selection for hematopoietic stem cell isolation and transplantation is unclear. The present study compared colony formation and endothelial cell differentiation of these two cell types from umbilical cord blood (UCB). METHODS: Mononuclear cells from the same UCB samples were used for both CD133(+) and CD34(+) cell selection. Cells with 97.1% purity were incubated in semi-solid culture medium containing stem cell growth factor (SCGF) and G-CSF or erythropoietin (EPO). Purified cells were also cultured in M199 containing vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and insulin-like growth factor-1 (IGF-1). RESULTS: CD34(+) and CD133(+) cells produced similar numbers of CFU-GM colonies (median 43.25 and 30.5, respectively; P>0.2). However, a greater than four-fold difference in BFU-E colony formation was observed from CD34(+) cells compared with CD133(+) cells (median 35 and 8, respectively; P<0.04). CD34(+) cells gave rise to endothelial-like cells when stimulated with VEGF, bFGF and IGF-1. CD133(+) cells were unable produce this cell type under the same conditions. DISCUSSION: CD133(+) cells produced smaller BFU-E colonies and were unable to differentiate into mature endothelial cells. CD34(+) cells contained endothelial progenitors that could differentiate into mature cells of this lineage. Based on these data, it appears that CD133 offers no distinct advantage over CD34 as a selective marker for immunoaffinity-based isolation of hematopoietic stem cells and endothelial progenitor cells.

Dynamics of {beta}-amyloid reductions in brain, cerebrospinal fluid, and plasma of {beta}-amyloid precursor protein transgenic mice treated with a {gamma}-secretase inhibitor.

gamma-Secretase inhibitors are one promising approach to the development of a therapeutic for Alzheimer's disease (AD). gamma-Secretase inhibitors reduce brain beta-amyloid peptide (Abeta), which is believed to be a major contributor in the etiology of AD. Transgenic mice overexpressing the human beta-amyloid precursor protein (APP) are valuable models to examine the dynamics of Abeta changes with gamma-secretase inhibitors in plaque-free and plaque-bearing animals. BMS-299897 2-[(1R)-1-[[(4-chlorophenyl)sulfony](2,5-difluorophenyl)amino]ethyl]-5-fluorobenzenepropanoic acid, a gamma-secretase inhibitor, showed dose- and time dependent reductions of Abeta in brain, cerebrospinal fluid (CSF), and plasma in young transgenic mice, with a significant correlation between brain and CSF Abeta levels. Because CSF and brain interstitial fluid are distinct compartments in composition and location, this correlation could not be assumed. In contrast, aged transgenic mice with large accumulations of Abeta in plaques showed reductions in CSF Abeta in the absence of measurable changes in plaque Abeta in the brain after up to 2 weeks of treatment. Hence, CSF Abeta levels were a valuable measure of gamma-secretase activity in the central nervous system in either the presence or absence of plaques. Transgenic mice were also used to examine potential side effects due to Notch inhibition. BMS-299897 was 15-fold more effective at preventing the cleavage of APP than of Notch in vitro. No changes in the maturation of CD8(+) thymocytes or of intestinal goblet cells were observed in mice treated with BMS-299897, showing that it is possible for gamma-secretase inhibitors to reduce brain Abeta without causing Notch-mediated toxicity.

Macronutrient intakes of elderly in the Lipid Research Clinics Program Prevalence Study.

As part of the Lipid Research Clinics (LRC) Program Prevalence Study of coronary heart disease risk factors, nutrient intakes of two US populations over 59 years of age were determined by 24-hour recalls in the 1970s. Characteristics of the populations were (1) California: suburban, upper-middle class, 95% high school graduates, 10% blue collar occupations; (2) Oklahoma: rural lower-middle class, 75% high school graduates, and 40% blue-collar occupations. Macronutrients consumed by both populations were similar, except for alcohol. For both men and women, energy intake was approximately 25 kcal/kg/day (body weight) sources of energy were approximately 40% from carbohydrate, 16% from protein, 37% from fat, and 4% from alcohol. The Oklahoma population, however, consumed significantly less alcohol than did Californians. Percentages of calories from fatty acids were approximately 14% from saturated and 6% from polyunsaturated, which yielded a polyunsaturated: saturated ratio of 0.48. The intake of cholesterol for women was 190 mg/1000 kcal and for men, 210 mg/1000 kcal. Between the ages of 60 and 69, the Oklahoma men consumed more energy than did the California men. Both sexes demonstrated lower energy intakes with advancing age and with increasing body mass index. The higher energy intake of the Oklahoma cohort aged 60-69 was attributed to the greater physical demands of their occupations, but this difference disappeared after age 70. The California and Oklahoma women had similar caloric intakes beyond age 60. In summary, the LRC findings suggest that geographically diverse American populations consumed in the late 1970s remarkably similar intakes of macronutients and cholesterol, with the only major exception being energy from alcoholic beverages.

OMERACT-OARSI initiative: Osteoarthritis Research Society International set of responder criteria for osteoarthritis clinical trials revisited.

BACKGROUND: The OARSI Standing Committee for Clinical Trials Response Criteria Initiative had developed two sets of responder criteria to present the results of changes after treatment in three symptomatic domains (pain, function, and patient's global assessment) as a single variable for clinical trials (1). For each domain, a response was defined by both a relative and an absolute change, with different cut-offs with regard to the drug, the route of administration and the OA localization. OBJECTIVE: To propose a simplified set of responder criteria with a similar cut-off, whatever the drug, the route or the OA localization. METHODS: Data driven approach: (1) Two databases were considered: the "elaboration" database with which the formal OARSI sets of responder criteria were elaborated, and the "revisit" database. (2) Six different scenarios were evaluated: The two formal OARSI sets of criteria; Four proposed scenarios of simplified sets of criteria. Data from clinical randomized blinded placebo controlled trials were used to evaluate the performances of the two formal scenarios with two different databases ("elaboration" versus "revisit") and those of the four proposed simplified scenarios within the "revisit" database. The placebo effect, active effect, treatment effect, and the required sample arm size to obtain the placebo effect and the active treatment effect observed were the performances evaluated for each of the six scenarios. Experts' opinion approach: Results were discussed among the participants of the OMERACT VI meeting, who voted to select the definite OMERACT-OARSI set of criteria (one of the six evaluated scenarios). RESULTS: Data driven approach: Fourteen trials totaling 1886 OA patients and fifteen studies involving 8164 OA patients were evaluated in the "elaboration"and the "revisit" databases respectively. The variability of the performances observed in the "revisit" database when using the different simplified scenarios was similar to that observed between the two databases ("elaboration" versus "revisit") when using the formal scenarios. The treatment effect and the required sample arm size were similar for each set of criteria. Experts' opinion approach: According to the experts, these two previous performances were the most important of an optimal set of responder criteria. They chose the set of criteria considering both pain and function as evaluation domain and requiring an absolute change and a relative change from baseline to define a response, with similar cut-offs whatever the drug, the route of administration or the OA localization. CONCLUSION: This data driven and experts' opinion approach is the basis for proposing an optimal simplified set of responder criteria for OA clinical trials. Other studies, using other sets of OA patients, are required in order to further validate this proposed OMERACT-OARSI set of criteria.

High-dose intravenous melphalan and autologous stem cell transplantation as initial therapy or following two cycles of oral chemotherapy for the treatment of AL amyloidosis: results of a prospective randomized trial.

SUMMARY: A prospective randomized trial was conducted to study the timing of high-dose intravenous melphalan and autologous stem cell transplantation (HDM/SCT) in AL amyloidosis. In all, 100 newly diagnosed patients were randomized to receive HDM/SCT, either as initial therapy (Arm-1) or following two cycles of oral melphalan and prednisone (Arm-2). The objectives of the trial were to compare survival and hematologic and clinical responses. With a median follow-up of 45 months (range 24-70), the overall survival was not significantly different between the two treatment arms (P=0.39). The hematologic response and organ system improvements after treatment did not differ between the two groups. Fewer patients received HDM/SCT in Arm-2 because of disease progression during the oral chemotherapy phase of the study, rendering them ineligible for subsequent high-dose therapy. This affected patients with cardiac involvement particularly, and led to a trend for an early survival disadvantage in Arm-2. Hence, newly diagnosed patients with AL amyloidosis eligible for HDM/SCT did not benefit from initial treatment with oral melphalan and prednisone, and there was a survival disadvantage for patients with cardiac involvement if HDM/SCT was delayed by initial oral chemotherapy.

The role of the tumour suppressor p33 ING1b in human neoplasia.

The inhibitor of growth (ING) genes (ING1-4) probably descend from tumour suppressor genes. ING1 was the first to be identified and later isolated using an approach to detect genes whose expression is suppressed in cancer. The others were isolated through homology and similarity searches in human and mouse databases. All members contain a plant homeodomain involved in macromolecule recognition. Apart from the extensively studied ING1, little is known about the number of transcripts encoded by the other members or their gene structure. ING1 encodes several differentially spliced mRNAs, which may produce a family of proteins. The most widely expressed protein isoform is p33(INGb1), which is involved in restriction of cell growth and proliferation, apoptosis, tumour anchorage independent growth, cellular senescence, maintenance of genomic stability, and modulation of cell cycle checkpoints. ING1 gene mutation is uncommon in cancer, although the subcellular localisation of p33(INGb1) may have an effect on its function. The p33(INGb1) cellular compartmental shift from the nucleus to the cytoplasm may cause loss of normal cellular function, and may play a central role in the pathogenesis of several cancers.

Downregulation of nuclear expression of the p33(ING1b) inhibitor of growth protein in invasive carcinoma of the breast.

BACKGROUND/AIMS: The inhibitor of growth gene 1 (ING1) is a modulator of cell cycle checkpoints, apoptosis, and cellular senescence. The most widely expressed ING1 isoform is p33(ING1b), which can modulate p53, a molecule that is frequently altered in breast cancer. Reduced ING1 mRNA expression has been observed in primary breast cancer expressing wild-type p53. METHODS: p33(ING1b), p53, oestrogen receptor (ER), and progesterone receptor (PgR) expression was studied in 86 primary invasive breast cancers using immunohistochemistry. RESULTS: Reduced nuclear expression of p33(ING1b) was found in cancer cells, both in intensity and the proportion of cells staining. This was associated with enhanced cytoplasmic p33(ING1b) expression in a proportion of cases. Analysis of several known biological factors indicated that high grade tumours were of larger size and more often negative for ER and PgR expression. However, larger tumours were more frequently p53 negative. These results provide evidence that p33(ING1b) alterations are associated with more poorly differentiated tumours. Positive correlations were found between nuclear p33(ING1b) expression and both ER and PgR expression. CONCLUSIONS: Optimum function of p53 is dependent on p33(ING1b) so that a reduction of nuclear p33(ING1b) expression, as seen in this series, would be predicted to compromise p53 function. This study showed that p33(ING1b) alterations were associated with more poorly differentiated tumours. Therefore, p33(ING1b) expression could be used as a marker of differentiation in invasive breast cancer. These results support the view that loss of p33(ING1b) may be an important molecular event in the differentiation and pathogenesis of invasive breast cancer.

Isoflavones and skeletal health: are these molecules ready for clinical application?

A review of the recent literature on the effects of isoflavones was undertaken to determine whether molecules such as genistein and daidzein, aglycone derivatives of soybeans, might have benefit in the prevention and treatment of osteoporosis. The current standard for science-based medicine is the documentation of efficacy of an agent under controlled, randomized, prospective conditions. A few short clinical investigations have been undertaken using isoflavones (along with soy protein), but they had limitations in study design, and the numbers of women studied were small. Other evidence from animal models, in vitro experiments, and epidemiological reports suggest that the isoflavones have skeletal benefits in women with little or no ovarian estrogen production. A clear need exists for prospective human trials, using the required conditions of randomized clinical trials and designs, to satisfy objectively the needs for science-based medicine and for appropriate clinical applications.

Metabotropic glutamate receptor 5 antagonist-induced stimulation of hypothalamic-pituitary-adrenal axis activity: interaction with serotonergic systems.

The mGluR5 antagonist 2-methyl-6-(phenylethynyl) pyridine (MPEP) produces anxiolytic or antidepressant effects in several rodent models through incompletely described mechanisms. Anxiolytics and antidepressants share several neuroendocrine features, including acute activation of the hypothalamic-pituitary-adrenal (HPA)-axis, desensitization of neuroendocrine responses with repeated dosing, and desensitization of the HPA axis to 5-HT1A agonist stimulation. We characterized these neuroendocrine parameters in rats treated systemically with MPEP and compared them to those induced by the anxiolytic buspirone. Acutely, MPEP dose-dependently (0.1-10 mg/kg i.p.) increased plasma corticosterone concentrations. These responses were blocked by 50% with the 5-HT1A antagonist WAY100635. The corticosterone responses to both 3 mg/kg MPEP and buspirone were decreased by 80% after 5 days of twice-daily injections. Repeated injection with MPEP decreased HPA-axis sensitivity to buspirone challenge by 75%. This desensitization was not associated with changes in mGluR5 or 5-HT1A receptor binding properties, expression of G-protein subunits coupled to these receptors, or in 5-HT-stimulated binding of [(3)H]-GTPgammaS to membranes. We conclude that MPEP acutely disinhibits the HPA axis, in part through uncharacterized changes in serotonergic signaling. Desensitization of 5-HT1A responses after repeated MPEP administration may indicate that, like other anxiolytics and antidepressants, plasticity in 5-HT signal transduction pathways has occurred.