Physical activity and dietary calcium interactions in bone mass in Scottish postmenopausal women.

UNLABELLED: In this population-based cohort of 1,254 older Scottish women we found significant interactions between the mechanical component of self-reported habitual physical activity (PA) and dietary calcium (Ca) in BMD, independent of other risk factors. At low and/or medium Ca intakes BMD was higher amongst the most active people. INTRODUCTION: Although there is general agreement that increased activity (PA) and dietary calcium (Ca) consumption may help maintain bone mass in later life and prevent fractures, the amount required remains uncertain. METHODS: In 2001-2003, 1,847 postmenopausal women (mean +/- SD age: 69.3 +/- 5.5 years) underwent bone mineral density (BMD) measurement and, in 2004, 68.7% (n = 1,254) completed a bone-specific Physical Activity Questionnaire (bsPAQ) and a food frequency questionnaire. The bsPAQ measures the metabolic and mechanical components of PA. Interactions of PA and Ca in BMD were examined using ANCOVA. RESULTS: Significant interactions were identified in the BMD of the lumbar spine (LS), right hip (RH) and left hip (LH), after adjustment for confounders, between tertiles of PA classified according to the mechanical component and tertiles of energy-adjusted Ca intake (ANCOVA p = 0.006, p = 0.004 and p = 0.013 respectively). For example, at medium Ca intakes LH BMD was higher by 7.8% in the highest tertile of PA compared with the lowest tertile of PA. CONCLUSIONS: These data suggest that health promotion campaigns to increase PA would be most effective in populations with a low/medium calcium intake.

Estimating the heritability of female lifetime fecundity in a locally adapted Drosophila melanogaster population.

The heritability of genome-wide fitness that is expected in finite populations is poorly understood, both theoretically and empirically, despite its relevance to many fundamental concepts in evolutionary biology. In this study, we used two independent methods of estimating the heritability of lifetime female fecundity (the predominant female fitness component in this population) in a large, outbred population of Drosophila melanogaster that had adapted to the laboratory environment for over 400 generations. Despite strong directional selection on adult female fecundity, we uncovered high heritability for this trait that cannot be explained by antagonistic pleiotropy with juvenile fitness. The evolutionary significance of this high heritability of lifetime fecundity is discussed.

Assessing the extent of genome-wide intralocus sexual conflict via experimentally enforced gender-limited selection.

Intralocus sexual conflict, which occurs when a trait is selected in opposite directions in the two sexes, is a taxonomically widespread phenomenon. The strongest genetic evidence for a gender load due to intralocus sexual conflict comes from the Drosophila melanogaster laboratory model system, in which a negative genetic correlation between male and female lifetime fitness has been observed. Here, using a D. melanogaster model system, we utilize a novel modification of the 'middle class neighbourhood' design to relax selection in one sex, while maintaining selection in the other. After 26 generations of asymmetrical selection, we observed the expected drop in fitness of the non-selected sex compared to that of the selected sex, consistent with previous studies of intralocus sexual conflict in this species. However, the fitness of the selected sex also dropped compared to the base population. The overall decline in fitness of both the selected and the unselected sex indicates that most new mutations are harmful to both sexes, causing recurrent mutation to build a positive genetic correlation for fitness between the sexes. However, the steeper decay in the fitness of the unselected sex indicates that a substantial number of mutations are gender-limited in expression or sexually antagonistic. Our experiment cannot definitively resolve these two possibilities, but we use recent genomic data and results from previous studies to argue that sexually antagonistic alleles are the more likely explanation.

Sexual conflict is not counterbalanced by good genes in the laboratory Drosophila melanogaster model system.

Sexual conflict theory is based on the observation that females of many species are harmed through their interactions with males. Direct harm to females, however, can potentially be counterbalanced by indirect genetic benefits, where females make up for a reduction in offspring quantity by an increase in offspring quality through a generic increase in offspring fitness (good genes) and/or one restricted to the context of sexual selection (sexy sons). Here, we quantify the magnitude of the good genes mechanism of indirect benefits in a laboratory-adapted population of Drosophila melanogaster. We find that despite high-standing genetic variance for fitness, females gain at most only a modest benefit through the good genes form of indirect benefits--far too little to counterbalance the direct cost of male-induced harm.

Assessment of body image in obesity using a digital morphing technique.

BACKGROUND: Historically, body image research has relied on generic, whole body outlines, which may not be suited to obese individuals. The development of computer generated, individualized digital images to represent body image may be more effective. METHODS: Sixty volunteers participated, with three categories of subject: lean, obese and lean regular exercisers. Body image was assessed using a digital morphing technique in comparison to two standard paper questionnaires. RESULTS: Using the novel digital morphing tool, obese subjects displayed poorer body awareness (perception) than their lean counterparts (P = 0.03), significantly over-estimating their actual body size. Both genders overestimated body size to a similar degree. For body satisfaction, females wished to be smaller and males to be larger, identifying gender-specific body regions (P < 0.001). Obese subjects showed greatest dissatisfaction (P < 0.001) with body image. There was significant correlation for body image dissatisfaction (P < 0.05) between the digital technique and the questionnaires, which was highest for the figural stimuli questionnaire (r = 0.80, P < 0.001). CONCLUSIONS: This method represents a novel and alternative approach to rating body image perception (IP) and satisfaction in obese subjects, particularly providing data on specific regional areas. Body image dissatisfaction appears to be both due to poor body IP compounded with the desire to be smaller.

The effect of pitched and vertical ladder ergometer climbing on cardiorespiratory and psychophysical variables.

This study aimed to assess whether modifying the pitch of a 75° ladder ergometer to vertical had a cardiorespiratory or psychophysical effect on climbing. Nine male participants climbed a ladder ergometer at 75° and subsequently at 90°, adjusted for an equivalent vertical climb rate, completing three climbing bouts at different vertical speeds. One participant dropped out being unable to complete the climb under the 90° condition. Each was monitored for heart rate (HR), V˙O2 and rating of perceived exertion (RPE). Results showed vertical climbing induced higher V˙O2 (mean increase 17.3%), higher HR (mean increase 15.8%), and higher RPE at all speeds and that moving from 75°to vertical exacerbates the effect of speed on the cardiorespiratory response to climbing. This may be explained by increased force production required to maintain balance in a vertical climbing position when the body's centre of mass is not above the feet.

Correcting calf girth discriminates the incidence of falling but not bone mass by broadband ultrasound attenuation in elderly female subjects.

Calf circumference has been cited as an independent risk factor for hip fracture. Correcting this measured girth for subcutaneous adipose tissue or fluid accumulation provides a more valid estimate of lean tissue, but has not been reported in elderly populations. Two hundred eighty-eight randomly selected female volunteers, aged >or=70 years, were assessed by quantitative ultrasound (QUS) and clinical risk factors as part of a larger screening study for hip fracture risk. This involved measuring broadband ultrasound attenuation (BUA) and administering a structured risk factor questionnaire that included estimated daily skeletal loading (time standing or walking). Body mass index (BMI) was estimated using current body mass and height at age 25 years. Calf girth was measured using a standard anthropometric tape, the medial calf skinfold (a vertical fold at the point of maximum calf girth) was measured, and corrected calf girth (CCG) was calculated by subtracting the skinfold (in centimeters) multiplied by pi from calf girth. Subjects were aged 76.9 +/- 5.0 years, had BMIs of 24.3 +/- 3.9 kg/m(2), and spent an average of 5.5 +/- 2.0 h on their feet each day. Age, current body mass, BMI calf girth, and CCG all correlated with BUA (p < 0.01). CCG correlated with hours on the feet (p < 0.05), whereas calf girth did not (p > 0.05). Dividing the sample into tertiles by these correlates of BUA and predicting BUA using stepwise regression revealed different predictors for each tertile. Of the total sample, 93 had fallen in the last 12 months, whereas 195 had not. Independent t-tests showed these groups to be similar in age, BMI, and calf girth (p > 0.05), but fallers spent less time on their feet each day, and had smaller CCG (p < 0.05). This suggests that larger calf muscles may be protective against falling-possibly as a result of enhanced stability or greater neuromuscular control.

Modeling elite male athletes' peripheral bone mass, assessed using regional dual x-ray absorptiometry.

There is still considerable debate as to whether bone mineral content (BMC) increases in proportion to the projected bone area, A(p), or an estimate of the skeletal bone volume, (A(p))(3/2), being assessed. The results from this study suggest that the bone mass acquisition of elite athletes' arms and legs increases in proportion to the projected bone area, A(p), having simultaneously controlled/removed the effect of the confounding variables of body mass and body fat. Although this supports the use of the traditional bone mineral density ratio (BMD=BMC/A(p)), it also highlights the dangers of overlooking the effect of known confounding variables. Ignoring the effect of such confounding variables, athletic groups whose activities involve upper body strength (rugby, rock climbing, kayaking, weight lifting) had the highest arm BMD, while runners were observed to have the lowest arm BMD (lower than that of the controls). Similarly, leg BMD was highest in rugby players, whose activities included both running and strength training. However, the rugby players were also observed to have the greatest body mass. When the important determinants of body mass, body fat, as well as projected bone area, A(p), were incorporated as covariates into a proportional allometric ANCOVA model for BMC, different conclusions were obtained. The introduction of these covariates had the effect of reducing the sporting differences on adjusted arm BMC, although the "sport" by "side" interaction still identified racket players as the only group with a greater dominant arm BMC (P < 0.05). In contrast, sporting differences in adjusted leg BMC remained highly significant, but with a rearranged hierarchy. The runners replaced the rugby players as having the greatest adjusted leg BMC. The results confirm the benefits of activity on peripheral bone mass as being site-specific but reinforce the dangers of making generalizations about the relative benefits of different exercises ignoring the effects of known confounding variables, such as body size, body composition, and age.

Relations between erythrocyte lithium efflux, blood pressure and family histories of hypertension and cardiovascular disease: studies in a factory workforce and hypertension clinic.

Sodium-dependent lithium efflux was measured in erythrocytes from 399 factory workers and 125 patients attending a hypertension clinic. Thirty-two factory workers had unsuspected essential hypertension (diastolic blood pressure phase V greater than 90 mmHg). These subjects had the same average erythrocyte lithium efflux as those with normal blood pressure, whereas lithium efflux was increased on average in the clinic hypertensives. Lithium efflux was greater in those subjects from both groups who had a family history of high blood pressure. Our clinic hypertensives did not have raised lithium efflux when they were matched for family history; the increased lithium efflux in the group as a whole (and in analysis of published reports) was explained by an excess of subjects with a family history of hypertension. Furthermore, when a family history of hypertension was present, lithium efflux was increased on average only in those whose relatives also had a cardiovascular event associated with their high blood pressure. These results, in conjunction with detailed analysis of the distributions of lithium efflux within the groups, suggest that, though not linked to blood pressure itself, an increase in lithium efflux is an inherited marker for those at risk from the cardiovascular complications associated with high blood pressure.

Epitopes within the HLA-B5,B35 cross-reacting group.

The HLA-B5,B35 cross-reacting group is a large and serologically complex antigen family which includes the World Health Organization-recognized specificities HLA-B5,B51,Bw52,B35,Bw53,B18,Bw70,Bw71, and Bw72. In addition, several variants of antigens in this cross-reacting group have been described in the past but have not yet gained official recognition. A genetic basis for the complexity and the protein and molecular bases of this highly cross-reactive and polymorphic cross-reacting group have yet to be established. The potential contributions of shared amino acid sequences, the occurrence of multiple epitopes on a single HLA-B molecule, and the presence of new HLA-C antigens have been difficult to resolve. To address this issue, we have carefully examined the serologic reactions of more than 900 allo- and monoclonal antibodies (Tenth International Workshop, Third Asia-Oceanic Workshop, and local reagents) versus lymphocytes from 92 individuals of diverse ethnic origin (North American Caucasians, North American blacks, Amerindians, Middle Eastern Caucasians), 84 of whom were informative for the HLA-B5,B35 cross-reacting group and related antigens. Our results demonstrate that the HLA-B5,B35 gene products share different combinations of distinct epitopes. We have constructed a model for the evolution of this cross-reacting group by assigning polarity to distinct diversification steps utilizing principles of maximum parsimony.

A rapid PCR-based method to distinguish between fetal and maternal cells in chorionic biopsies using microsatellite polymorphisms.

In some chorionic villus biopsy (CVB) cases the fetal/maternal origin of the tissue obtained is uncertain. An approach which only requires small amounts of CVB tissue to establish its origin is described. Since it is only the samples typed as female that could be either fetal or maternal, a paternal X chromosome contribution is sought by using highly polymorphic X-linked microsatellites.

Clonality of CD3 negative large granular lymphocyte proliferations determined by PCR based X-inactivation studies.

AIMS: To examine persistent CD3-large granular lymphocytosis (LGL) cases for clonality, both by lineage specific (T cell receptor) and lineage independent (X-inactivation) molecular methods; and to find out whether X-inactivation studies are more appropriate than gene rearrangement studies for this subset of LGL disorders. METHODS: Patients were selected who had LGL of more than six months' duration and identified as CD3- by immunophenotyping. T cell receptor studies and, where possible, X-inactivation studies of the phosphoglycerate kinase (PGK) gene were carried out. Analysis of subpopulations was carried out on cases heterozygous for PGK by the use of a polymerase chain reaction (PCR) method for X-inactivation. RESULTS: Of 17 CD3- LGL cases studied, all were found to be germline for beta, gamma, and delta T cell receptor studies, and immunoglobulin heavy chain genes. However, six of these were analysed by X-inactivation of the PGK gene and two cases gave clonal band patterns but only within the CD3- subpopulation. CONCLUSIONS: Clonal analysis by the lineage independent method of X-inactivation allows clonal expansion undetected by T and B cell specific markers to be identified. It is therefore a more appropriate method for the analysis of CD3- LGL. This has implications for diagnosis in CD3- LGL disorders.

Clinical results of hydrogel lens implantation.

Polymethylmethacrylate has proven to be a useful intraocular lens (IOL) implant material and remains the most widely used material for the fabrication of IOLs. Complications, however, from IOL implantation still occur. A hydrogel lens has been designed for posterior chamber placement. A clinical study from August 1983 to June 1985 was undertaken to determine the safety and efficacy of this new lens manufactured from 38% poly HEMA. The noninflammatory postoperative complications were limited to lens decentration and opacification of the lens capsule. Three cases of posterior capsule opacification required YAG laser capsulotomy. Laser capsulotomy is feasible and the lens appeared to be more resistant to damage from the YAG laser than polymethylmethacrylate lenses. In general, the material appeared to be well tolerated and there have been no cases of persistent iritis or clinically detectable cystoid macular edema. If the visual acuity outcome by age decade for all patients irrespective of follow-up time is considered, 92% of patients achieved 20/40 or better corrected visual acuity.

Total and regional bone density in male runners, cyclists, and controls.

PURPOSE: Male athletes who were runners (N = 12), cyclists (N = 14), or both (N = 13) were compared with nonexercising age-matched controls (N = 23) for total and regional bone mineral density (BMD). All athletic subjects had competed for a minimum of 3 yr and trained for a minimum of 4 h x wk(-1). Runners undertook no cycling and cyclists undertook no running training. METHODS: All subjects were scanned for whole body and L1-L4 spine BMD using a Hologic QDR 1000W scanner (Hologic Inc., Bedford, MA). RESULTS: There were no differences in age, height, weight, body mass index (BMI), % fat, or hours of training between any of the athletic groups (P > 0.05), although compared with controls, runners and cyclists had lower body mass index (P < 0.01) and all athletic groups had lower % fat (P < 0.001). Compared with controls, runners had greater total and leg BMD (P < 0.05), cyclists had reduced spine BMD (P = 0.05), and athletes of the "both" group had greater total (P < 0.05) and arm BMD (P < 0.01). CONCLUSION: Running is associated with increased bone density, particularly in the leg, whereas cycling is associated with a mild decrease in bone density in the spine. In athletes who do both, running exerts a stronger influence than cycling.

A rapid HPLC method for monitoring plasma levels of caffeine and theophylline using solid phase extraction columns.

A simple HPLC method for the determination of caffeine and theophylline in plasma is described. Separation of theobromine, paraxanthine, theophylline, beta-hydroxyethyltheophylline and caffeine is obtained using a mobile phase of 1% acetic acid/methanol (83:17, v/v) and a Waters Associates NOVA-PAK C18 column protected by a Guard-PAK precolumn module containing a Guard-PAK CN cartridge. Rapid sample preparation is achieved by solid-phase extraction columns (Bond-Elut C18, 1 mL capacity) which provide excellent recovery values for both drugs. The cost per sample using this approach can be minimised by column regeneration and re-use. Results obtained for theophylline are in good agreement with values determined by other techniques.

Body composition measurement: a hierarchy of methods.

The range of methods now available to estimate body composition is extensive. In most cases there is a relationship between cost, complexity and information content. The consequence is that choices can still be made depending on the finances available and the needs of the health professional. This paper reviews four methods ranging in availability and clinical detail. The alternatives are use of skinfolds, electrical impedance, underwater weighing and dual energy X-ray absorptiometry. These should provide the practitioner with viable options to consider in the assessment of body composition. Although no method has been designed specifically for children, reference is made throughout to studies on paediatric subjects of the major issues involved in these methods, which will assist paediatric endocrinologists in making informed decisions.