Effects of dietary restraint and oral contraceptives on bone strength and bone turnover in young women

ABSTRACT Introduction The purpose of this study was to assess specific osteoporosis-related health behaviours and physiological outcomes including daily calcium intake, physical activity levels, bone strength, as assessed by quantitative ultrasound, and bone turnover among women between the ages of 18 and 25. Respective differences on relevant study variables, based on dietary restraint and oral contraceptive use were also examined. Methods One hundred women (20.6 ± 0.2 years of age) volunteered to participate in the study. Informed written consent was obtained by all subjects prior to participation. The study and all related procedures were approved by the Brock University Research Ethics Board. Body mass, height, relative body fat, as well as chest, waist and hip circumferences were measured using standard procedures. The 10-item restrained eating subscale of the Dutch Eating Behaviour Questionnaire (DEBQ) was used to assess dietary restraint (van Strien et al., 1986). Daily calcium intake was assessed by the Rapid Assessment Method (RAM) (Hertzler & Frary 1994). Weekly physical activity was documented by the 4-item Godin Leisure-Time Exercise Questionnaire (Godin & Shephard 1985). Bone strength was determined from the speed of sound (SOS) as measured by QUS (Sunlight 7000S). SOS measurements (m/s) were taken of the dominant and non-dominant sides of the distal one third of the radius and the mid-shaft of the tibia. Resting blood samples were collected from all subjects between 9am and 12pm, in order to evaluate the impact of lifestyle factors on biochemical markers of bone turnover. Blood was collected during the early follicular phase of the menstrual cycle (approximately days 1-5) for all subjects. Samples were centrifliged and the serum or plasma was aliquoted into separate tubes and stored at -80°C until analysis. The bone formation markers measured were Osteocalcin (OC), bone specific alkaline phosphatase (BAP) and 25-OH vitamin D. The bone resorption markers measured were the carboxy (CTx) and amino (NTx) terminal telopeptides of type-I collagen crosslinks. All markers were assessed by ELISA. Subjects were divided into high (HDR) and low dietary restrainers (LDR) based on the median DEBQ score, and also into users (BC) and non-users (nBC) of oral contraceptives. A series of multiple one way ANOVA's were then conducted to identify differences between each set of groups for all relevant variables. A two-way ANOVA analysis was used to explore significant interactions between dietary restraint and use of oral contraceptives while a univariate follow-up analysis was also performed when appropriate. Pearson Product Moment Correlations were used to determine relationships among study variables. Results HDR had significantly higher BMI, %BF and circumference measures but lower daily calcium intake than LDR. There were no significant differences in physical activity levels between HDR and LDR. No significant differences were found between BC and nBC in body composition, calcium intake and physical activity. HDR had significantly lower tibial SOS scores than LDR in both the dominant and non-dominant sites. The post-hoc analysis showed that within the non-birth control group, the HDR had significantly lower tibial SOS scores of bone strength when compared to the LDR but Aere were no significant differences found between the two dietary restraint groups for those currently on birth control. HDR had significantly lower levels of OC than LDR and the BC group had lower levels of BAP than the nBC group. Consistently, the follow-up analysis revealed that within those not on birth control, subjects who were classified as HDR had significantly (f*<0.05) lower levels of OC when compared with LDR but no significant differences were observed in bone turnover between the two dietary restraint groups for those currently on birth control. Physical activity was not correlated with SOS scores and bone turnover markers possibly due to the low physical activity variability in this group of women. Conclusion This is the first study to examine the effects of dietary restraint on bone strength and turnover among this population of women. The most important finding of this study was that bone strength and turnover are negatively influenced by dietary restraint independent of relative body fat. In general, the results of the present thesis suggest that dietary restraint, oral contraceptive use, as well as low daily calcium intake and low physical activity levels were widespread behaviours among this population of college-aged women. The young women who were using dietary restraint as a strategy to lose weight, and thus were in the HDR group, despite their higher relative body fat and weight, had lower scores of bone strength and lower levels of markers of bone turnover compared to the low dietary restrainers. Additionally, bone turnover seemed to be negatively affected by oral contraceptives, while bone strength, as assessed by QUS, seemed unaffected by their use in this population of young women. Physical activity (weekly energy expenditure), on the other hand, was not associated with either bone strength or bone tiimover possibly due to the low variability of this variable in this population of young Canadian women.

Effects of intracerebroventricular bombesin administration on local cerebral glucose utilization in the restrained and unrestrained rat

Intracerebroventricular (ICV) administration of bombesin (BN) induces a syndrome characterized by stereotypic locomotion and grooming, hyperactivity and sleep elimination, hyperglycemia and hypothermia, hyperhemodynamics, feeding inhibition, and gastrointestinal function changes. Mammalian BN-like peptides (MBNs), e.g. gastrin-releasing peptide (GRP), Neuromedin C (NMC), and Neuromedin B (NMB), have been detected in the central nervous system. Radio-labeled BN binds to specific sites in discrete cerebral regions. Two specific BN receptor subtypes (GRP receptor and NMB receptor) have been identified in numerous brain regions. The quantitative 2-[14C]deoxyglucose ([14C]20G) autoradiographic method was used to map local cerebral glucose utilization (LCGU) in the rat brain following ICV injection of BN (vehicle, BN O.1Jlg, O.5Jlg). At each dose, experiments were conducted in freely moving or restrained conditions to determine whether alterations in cerebral function were the result of BN central administration, or were the result of BN-induced motor stereotypy. The anteroventral thalamic nucleus (AV) (p=O.029), especially its ventrolateral portion (AVVL) (prestraint conditions. The effect was treatment dependent without interaction of the restraint conditions. Of all the regions that were reported to have high densities of BN receptors, the internal granular layer of the olfactory bulb (IGr) (p=O.028), and the suprachiasmatic nucleus (SCh) (p=O.003) exhibited BN treatment effects. BN effects on LCGU were also observed in the median eminence (ME) (p=O.011). Restraint, however, decreased LCGU in the lateral dorsal thalamic nucleus, ventrolateral and dorsomedial parts (LOVL and LOOM) (p=O.044, p=O.009), and the lateral geniculate (LG) (p=O.027). In sum, BN induced a marked and highly localized alteration in cerebral metabolism within parts of the anterior thalamus, which is the principle relay in the limbic circuitry. BN effects were also observed in IGr, Mi, SCh, and ME. Effects of restraint were found in LOVL, LOOM, and LG. It is suggested that increased LCGU in AV and AVVL may be the result of functional change in the limbic circuitry and the hypothalamus caused by BN receptor functional modification. In IGr, increased LCGU following BN administration is considered to be mainly the result the activation of NMB receptor, a subtype of BN receptors. In SCh, increased LCGU is believed to be caused both by BN effects on the thalamic, the hypothalamic, and the limbic functions and by activation of GRP receptor, another BN receptors subtype found in SCh. In ME, increased LCGU is suggested to be caused by BN effects on the hypothalamic functions, especially those related to the neuroendocrine functions. None of the alterations seen in these regions reflects the emission of stereotyped motor behaviors. Rather, they reflect a direct influence of BN central administration upon functioning of the cerebral regions influenced by BN administration. The restraint effects seen in LO, including LOOM and LOVL, are suggested to be the result of altered behavioral expression. The restraint effects seen in LG is suggested to be the result of reduced locomotion.

Weight-preoccupation, personality and depression in university students : an interactionist perspective

The present research was designed to examine Beck's (1983; 1987) cognitive diathesis-stress model of depression in a new context. Specifically, this cross-sectional study investigated whether Beck's cognitive-personality traits of sociotropy and autonomy interacted with a specific daily hassle/stressor, weightpreoccupation, in the prediction of depressed mood in women and men. Weightpreoccupation was chosen as the particular daily stressor, because, according to Kanner, Coyne, Schaeffer, and Lazarus (1981). concern about weight and physical appearance were two of the most troublesome daily hassles among university students. ContraIy to current stereotypes, men also express concerns with weight and appearance (Cash, Winstead, &, landi, 1986), in both the direction of weight loss and weight/muscle gain (Drewnowski &, Yee, 1987). Thus, unique to this study was the examination of weight-preoccupation in men, not only in the direction of weight loss, but also in the direction of weight and muscle gain. Two hundred and fifty-one undergraduates were administered the revised SociotropyAutonomy Scale (SAS), the Beck Depression Inventory (BDij, the Hassles and Uplifts Scale, the Eating Disorders Inventory (EDI), and the Restraint Scale (RS). Through a process of model building, a final model was devised in which depression (ie., BDI total scores) was regressed on personality (Le., SAS Sociotropy) and weight-preoccupation (i.e., Drive for Thinness, Body Dissatisfaction, and the Restraint Scale). Separate hierarchical multiple regression analyses, with BDI as the dependent variable, were carried out for each of the 2 3 weight-preoccupation variables. Results revealed a specific congruent interaction between weight,..preoccupation and personality. Specifically, drive for thinness and body dissatisfaction interacted with sociotropy to predict depressed mood in both women and men, but the interaction between sociotropy and the Restraint Scale was marginal. Findings suggested that weight-preoccupied women and men experienced depressed mood to the extent that they were characterized as more highly sociotropic. As predicted, personality (i.e., sociotropy), moderated the relationship between daily stress (i.e., weight-preoccupation) and depression. Thus, results revealed that the proposed diathesis-stress model seemed to operate in the same manner for women and men. Moreover, the examination of weightpreoccupation among men (i.e., in the direction of both weight loss and weight/muscle gain) further revealed that, when curvilinearity was taken into account, highly sociotropic men, who had a low desire to gain weight and muscle mass (i.e., most likely those who desired to lose weight), experienced higher levels of depressed mood than those who had a "medium" desire for weight and muscle gain. However, the highest levels of depressed mood was experienced by highly sociotropic men who were highly weight-preoccupied in the direction of wanting to gain weight and muscle mass. In addition, possible reasons for the present fmdings, as wen as iimitations and impiicalions for future research are discussed.

Polyglutamine monomer structure and its implications for molecular self-assembly

Polyglutamine is a naturally occurring peptide found within several proteins in neuronal cells of the brain, and its aggregation has been implicated in several neurodegenerative diseases, including Huntington's disease. The resulting aggregates have been demonstrated to possess ~-sheet structure, and aggregation has been shown to start with a single misfolded peptide. The current project sought to computationally examine the structural tendencies of three mutant poly glutamine peptides that were studied experimentally, and found to aggregate with varying efficiencies. Low-energy structures were generated for each peptide by simulated annealing, and were analyzed quantitatively by various geometry- and energy-based methods. According to the results, the experimentally-observed inhibition of aggregation appears to be due to localized conformational restraint placed on the peptide backbone by inserted prolines, which in tum confines the peptide to native coil structure, discouraging transition towards the ~sheet structure required for aggregation. Such knowledge could prove quite useful to the design of future treatments for Huntington's and other related diseases.

Chapter 10: Antemortem Handling and Welfare

The chapter discusses the following topics: Continuous Measurement and Monitoring, Meat Quality Correlations, How Stressful is Slaughter?, Causes of Poor Welfare Audit Scores, Animal Vision, Hearing and Smell, Basic Handling Principles, Handler Movement Patterns, Design of Handling Facilities, Design and Operation of Restraint Devices, Stunning, Stunning Method and Blood-Splash, Bruising and Meat Quality.

The Design and Construction of Facilities for Handling Cattle

The article focuses on the following: Cattle Perception, How to prevent Balking, Solid Fences, Flight Zone, Curved Race more Efficient, Curved Race and Crowd Pen Dimensions, Loading Ramps, Working Corral for a Large Ranch, Squeeze Chutes and Headgates, Calf Tables, Artificial Insemination Chute, New Restraint Ideas, Dipping Vats, Bruise and Injury Prevention, Washable Facilities.