Adult Female Age Research Articles

DETERMINING THE ADULT AGE OF THE ORIENTAL LATRINE FLY, CHRYSOMYA MEGACEPHALA (FABRICIUS) (DIPTERA: CALLIPHORIDAE) BY PTERIDINE FLUORESCENCE ANALYSIS

AbstractThe relationship between head pteridine fluorescence (HPF) levels and age in adult females and males of a common necrophagous fly, Chrysomya megacephala, and effects of temperature and fly sex on the relationship were studied by pteridine fluorescence spectrophotometry. Factors affecting HPF levels in flies were found to include fly age, temperature and fly sex, among which the fly age was the most dominant one. There were significant linear relationships between HPF levels and age both for female and male adult flies at five constant temperatures, i. e. 16°C, 20°C, 24°C, 28°C and 32°C. The relationship between mean rate of pteridine accumulation (FV or MV) and temperature (t) could be well described by a modified exponential equation of FV=0.01288 e(0.2241t‐3.127)+0.3649 (r2= 0.9987) for females and a linear regression equation of MV= 0.0574 t ‐ 0.3637 (r2= 0.9557) for males. Using the information from the experiments at five constant temperatures, three calculated methods as the candidates were developed for accurately determining the age of the fly by HPF levels at ambient temperature. The results revealed that these three methods were suitable for estimating the age only for male flies, but not for female flies. The smallest average error of the predicated age was 2.55 days for males. In addition, how to employ which of these three developed methods for determining ages of male flies in practical was also discussed.

Variable age structure and apparent density dependence in survival of adult ungulates.

Large herbivores have strongly age-structured populations. Because recruitment often decreases as population density increases, in unexploited populations the proportion of older adults may increase with density. Because survival senescence is typical of ungulates, ignoring density-dependent changes in age structure could lead to apparent density-dependence in adult survival. To test for density dependence in adult survival, we used data from three populations that underwent considerable changes in density. Bighorn sheep (Ovis canadensis) on Ram Mountain, Alberta, ranged from 94 to 232, mountain goats (Oreamnos americanus) on Caw Ridge, Alberta, varied from 81 to 147, and estimates of roe deer (Capreolus capreolus) older than 1year at Chizé, France, ranged from 157 to 569. We used recent developments of capture-mark-recapture modelling to assess the response of adult survival to changes in density when age structure was and was not taken into account. Survival rates were 10-15% higher during the prime-age stage than during the senescent stage for all sex-species combinations. When adults were pooled into a single age class there was an apparent negative effect of density on female survival in bighorns and roe deer, and negative trends for female mountain goats, male roe deer and male bighorn sheep. When age class was taken into account, there were no significant effects of density on adult survival. Except for male mountain goats, the strength of density dependence was lower when age was taken into account. In ungulate populations, age structure is an important determinant of adult survival. Most reports of density dependence in adult survival may have been confounded by changes in age structure.

MMG AND EMG RESPONSES DURING 25 MAXIMAL, ECCENTRIC, ISOKINETIC MUSCLE ACTIONS

PURPOSE The purpose of this investigation was to examine mechanomyographic (MMG) and electromyographic (EMG) amplitude responses of the superficial quadriceps femoris muscles during 25 maximal, eccentric, isokinetic muscle actions of the dominant leg. METHODS Seven healthy, adult females (age 22.1 ± 2.4 y) volunteered to perform 25 eccentric muscle actions at 120°s−1, using a calibrated Cybex 6000 dynamometer. Bipolar surface electrode arrangements were placed on the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM). An MMG sensor was placed between the EMG electrodes on each muscle. The EMG and MMG amplitude values (root mean square), as well as peak torque (PT) were calculated for the 25 muscle actions, normalized to each respective maximal value, then averaged across all subjects. RESULTS Polynomial regression analyses indicated that PT demonstrated a cubic relationship (p < 0.05) across the 25 repetitions. Normalized EMG amplitude demonstrated a linear (p < 0.05) increase for the VL, a quadratic (p < 0.05) relationship for the RF, and no change (p > 0.05) for the VM across the 25 repetitions. Normalized MMG amplitude demonstrated a linear (p < 0.05) decrease for the VL and VM, and a cubic (p < 0.05) relationship for the RF across repetitions. There was no difference (p > 0.05) in slope values between the VL and VM for the normalized MMG amplitude versus repetition number relationship. CONCLUSION The differences found between the EMG amplitude and MMG amplitude of the VL, RF, and VM indicate dissociation between the two signals during repetitive, dynamic activity. The findings may also indicate that analysis of the EMG and MMG signals is useful for detecting the unique contribution of each muscle to torque production during such activity, since the responses differed between the VL, VM, and RF. For example, the MMG amplitude of the RF may have more influence on torque production in the present study, as evidenced by the similar pattern of its MMG amplitude response and PT over the 25 repetitions.

Contaminants in Svalbard polar bear samples archived since 1967 and possible population level effects

Blood plasma samples were collected in 1967 from 32 polar bears ( Ursus maritimus) in eastern Svalbard. These samples were stored frozen until 2001 and then analyzed for 33 polychlorinated biphenyls (PCB), two toxaphene congeners, DDTs, chlordanes (CHL), hexachlorobenzene, hexachlorocyclohexanes (HCHs), and polybrominated flame retardants (biphenyls and diphenyl ethers). The 1967 pollutant levels were compared with values from 1993 to 1994 for adult females and adult males to obtain insights into the historical development of pollution in the Norwegian Arctic. Differences in the OC levels measured between 1967 and 1993–1994 ranged from a decrease (PCB 187 and p, p-DDE) to unchanged in both sexes (PCBs 105, 118, 209, and HCH) to an increase in females (PCBs 99, 128, and CHL), to increases in both sexes (PCBs 138, 153, 156, 157, 170, 180, 194, and 206). The maximum change was a nine-fold increase in PCB 157 in adult females. Changes from 1967 to 1993–1994 in contaminant pattern expressed relative to PCB 153 could be explained by a combination of selective metabolism and accumulation of organochlorines in polar bears and temporal changes in the contaminant mixture being transported to the Arctic. Harvest of polar bears in Svalbard ended in 1973 and it appears that most pollutant levels were increasing at the same time that the population was expected to recover from over-harvest. The mean age of adult females in the Svalbard population was similar to other populations where pollution levels are lower but harvest is intense. Females with cubs-of-the-year ⩾16 years old are uncommon in the population for unknown reasons. The impacts of contaminants on the Svalbard polar bear population are inconclusive but there are suggestions of contaminant-related population level effects that could have resulted from reproductive impairment of females, lower survival rates of cubs, or increased mortality of reproductive females.

Perineural invasion in adenoid cystic carcinoma: Its causation/promotion by brain-derived neurotrophic factor

Adenoid cystic carcinoma (ACC) is a common salivary gland neoplasm with a lengthy clinical course and often late local recurrences after surgical resection. This is accounted for histologically by its infiltrative capacity and distinct propensity for perineural invasion. The expression of biological markers may help explain the clinicopathologic course in ACCs. Brain-derived neurotrophic factor (BDNF) is a growth factor known to be involved in neurogenesis. The aim of this study is to elucidate the expression of BDNF in ACCs, which is currently unknown. Twenty-nine cases of primary ACCs of the head and neck were immunostained to analyze BDNF protein expression. Staining intensity was described as focal or diffuse and graded on a 3-tiered scale. The study group comprised 20 adult females (age 30 to 78) and 9 adult males (age 22 to 70). Sites of involvement included the parotid gland (6 cases), nasopharynx (5), maxilla (4), palate (3), trachea (3), submandibular gland (2), buccal mucosa (2), mandible (1), tongue (1), lacrimal gland (1), and temporal region (1). All tumors exhibited diffuse cytoplasmic staining; 11 cases were classified as 1+ intensity, 12 cases as 2+, and six cases as 3+. Based on the results presented here, BDNF is unformly expressed by ACC and may play a causative role in its predilection for perineural invasion. ACCs may display neurogenesis with high levels of BDNF expression in some tumors. Further studies are warranted to gain better understanding of this possible relationship. HUM PATHOL 33:933-936. Copyright 2002, Elsevier Science (USA). All rights reserved.

Age, period and cohort effects on suicide rates in Australia, 1919-1999.

To examine age, period and cohort effects on Australian suicide rates. Male suicide rates for successive 5-year periods between 1919 and 1998, and for 1999 were displayed graphically to examine interactions between age, period and cohort effects. There has been a pronounced period effect on male suicide rates in all age groups over the last few decades, with lower rates in wartime and peak rates for most cohorts in the 1960s. Peak rates of all adult female 5-year age cohorts occurred in the 1960s or early 1970s. Most so-called cohort effects appear to be associated with environmental changes that may not be a function of the cohort itself. While much attention has focused on the rising suicide rates in young males in Australia, local media and health authorities have given little emphasis to the high rates found in elderly males.

Periods of extreme ankle displacement during one-legged standing.

The goal of this study was to describe the movement patterns of the ankle joint whilst standing on one leg. Ten healthy adult females (age 24 +/- 5.3 years) performed a one-legged standing task with eyes closed. Force platform recordings and video analyses were used to describe the kinematic and kinetic characteristics of the ankle joint during this task. A rocking movement of the foot (heel inversion-eversion) was documented by examining instances of extreme ankle displacement. Extreme ankle displacement was defined as any instant when the ankle position was more than +/- 2 SD away from the mean ankle joint position. Extreme values of lateral and medial ankle joint displacement were 14.8 and 9.2 mm, correspondingly. These instances of extreme foot inversion-eversion were characterized by large medial-lateral displacement of the gravity line (GLP) and center of pressure (COP) and large horizontal forces. Comparing instances of extreme ankle joint displacement to periods of non-extreme ankle displacement, the ankle joint moment remained fairly constant, averaging 8.4 +/- 4 and 6.9 +/- 3.5 Nm, respectively. The moment about the 'body-minus-foot' center of mass generated by the ankle joint reaction force, however, was on average over four times larger during instances of extreme ankle displacement (3.4 +/- 2.8 Nm), than during periods of non-extreme ankle displacement (0.8 +/- 0.4 Nm). In utmost situations, the moment due to the joint reaction force was up to 73% of the ankle joint moment. These results suggest that at least two different techniques are used to maintain balance during one-legged standing. The first technique, termed the ankle torque technique, involves a large restorative moment at a stationary ankle joint for balance maintenance. The other technique, the shear force technique, involves a large horizontal force at a moving ankle joint for balance maintenance. During non-extreme periods, balance was maintained primarily through the ankle torque technique. During extreme instances, a combination of both techniques was observed.

Gender-related differences of hyaluronic acid distribution in the human vocal fold.

To quantify the distribution of hyaluronic acid (HA) within the normal human vocal fold and evaluate gender- and age-related differences. Prospective, cross-sectional study by age and gender groups using cadaveric vocal folds to study hyaluronic acid differences. Twenty-five vocal fold halves obtained at autopsy were evaluated from nine adult male (age range, 34-52 y), seven adult female (age range, 21-41 y), four geriatric male (age range, 65-77 y), and five geriatric female (age range 65-82 y) subjects. Midmembranous vocal fold sections were stained for HA using the Muller-Mowry colloidal iron (acid mucopolysaccharide) stain with and without hyaluronidase. Digital imaging software was used to quantify the distribution of HA across the lamina propria at the vocal fold edge from superficial (subepithelial) to deep (vocalis muscle). A significant gender difference (P =.03) was noted in distribution when controlled for age. Combined, male subjects had a relatively constant distribution pattern throughout the depth of lamina propria. Female subjects showed relatively less HA in the first 15% of depth (most superficial) but showed more HA in the deeper 40% to 100% (toward vocalis muscle) than in male subjects. Important clinical implications may be extrapolated from our findings. First, relatively less HA in the most superficial area implies less protection from vibratory trauma and overuse and may explain in part why more female than male patients have phonotrauma to phonotraumatic lesions. Second, evaluating the distribution of HA in the normal human vocal fold allows more direction in our application of HA as a therapeutic lamina propria substitute in patients with voice disorders.

Age‐specific harvest mortality in a Norwegian mooseAlces alcespopulation

The annual age‐ and sex‐specific patterns of harvest mortality in a Norwegian mooseAlces alcespopulation during a period of 17 years for females and 24 years for males were estimated using cohort analysis. In males the harvest mortality increased with age, whereas in females the pattern was U‐shaped with higher harvest mortality of less fecund young (1–3 year) and old (≥ 10 years) age classes, and lower harvest mortality of prime age (4–9 years old) females. In both sexes, the calf harvest mortality was low, although it increased with increasing calf quotas following a change from an indiscriminate to a sex‐ and age‐specific hunting system during the study period. In adult males, the mortality pattern was opposite of what was expected based on the previously reported higher susceptibility to hunting of young than old males, indicating that hunter selectivity for large (old) males affected the pattern. Moreover, the selectivity of the hunters decreased as the hunting pressure increased, suggesting that the hunters became less selective when the mean time available per moose in the quota decreased. Among adult female age groups, the variation in harvest mortality increased with the proportion of calves per female in the population prior to hunting. This was mainly because of relatively higher mortality of post‐prime females, supporting our expectation that hunters avoid shooting females with calves and thus increase the harvest of less fecund age groups during high recruitment years. The observed selectivity led to harvest mortality that differed significantly from patterns of natural mortality, even where the mortality is mainly due to wolvesCanis lupusand bearsUrsus arctos.This may have consequences for the life history evolution of both male and female moose. The potential ecological, evolutionary and management implications of the results are discussed.

Biocultural analysis of sex differences in mortality profiles and stress levels in the late medieval population from Nova Rača, Croatia

Human skeletal remains of 104 individuals from the late medieval (14th–18th century) Nova Rača cemetery, in continental Croatia, are described. Historic data from the parish Book of the Dead, relevant to a period in the early 19th century, suggest that females may have been under greater stress than males. To test this hypothesis, the skeletal material is analyzed for the presence and distribution of enamel hypoplasias and cribra orbitalia. Observations are also made on the presence and pattern of dental disease, skeletal infection, trauma, osteoarthritis, vertebral degenerative changes, and Schmorl's depression frequencies. The mortuary sample, consisting of 36 subadults and 68 adults, exhibits underrepresentation of subadults, and differential adult male/female mortality profiles. Peak female mortality is between 21–25 years, compared to peak male mortality between 31–35 years. Average adult female age at death is 29.9 years, compared to 34.1 years in adult males. Significant sex differences are present in the frequencies of enamel hypoplasia. Adult females have higher frequencies of hypoplastic teeth, and a larger number of defects in the teeth affected than in males. Subadults in the series also exhibit higher frequencies of hypoplastic teeth, and a larger number of defects in the teeth affected than in adults, documenting a relationship between enamel hypoplasia-causing stress events and reduced life expectancy. Significant sex differences are also present in dental pathology frequencies, possibly reflecting differences in resource access. Sex differences in vertebral osteoarthritis and Schmorl's depression frequencies may reflect differential activity patterns. Am J Phys Anthropol 111:193–209, 1999. © 2000 Wiley-Liss, Inc.

Biocultural analysis of sex differences in mortality profiles and stress levels in the late medieval population from Nova Rača, Croatia

Human skeletal remains of 104 individuals from the late medieval (14th-18th century) Nova Raca cemetery, in continental Croatia, are described. Historic data from the parish Book of the Dead, relevant to a period in the early 19th century, suggest that females may have been under greater stress than males. To test this hypothesis, the skeletal material is analyzed for the presence and distribution of enamel hypoplasias and cribra orbitalia. Observations are also made on the presence and pattern of dental disease, skeletal infection, trauma, osteoarthritis, vertebral degenerative changes, and Schmorl's depression frequencies. The mortuary sample, consisting of 36 subadults and 68 adults, exhibits underrepresentation of subadults, and differential adult male/female mortality profiles. Peak female mortality is between 21-25 years, compared to peak male mortality between 31-35 years. Average adult female age at death is 29.9 years, compared to 34.1 years in adult males. Significant sex differences are present in the frequencies of enamel hypoplasia. Adult females have higher frequencies of hypoplastic teeth, and a larger number of defects in the teeth affected than in males. Subadults in the series also exhibit higher frequencies of hypoplastic teeth, and a larger number of defects in the teeth affected than in adults, documenting a relationship between enamel hypoplasia-causing stress events and reduced life expectancy. Significant sex differences are also present in dental pathology frequencies, possibly reflecting differences in resource access. Sex differences in vertebral osteoarthritis and Schmorl's depression frequencies may reflect differential activity patterns.

Lack of age-associated elevations in 24-h systolic and pulse pressures in women who exercise regularly.

We tested the hypothesis that the elevations in 24-h arterial systolic (SBP) and pulse (PP) pressures with age in sedentary adult females are absent or smaller in women who exercise regularly. Four groups of healthy normotensive women were studied: premenopausal (n = 12; 29 +/- 1 yr, mean +/- SE) and postmenopausal (n = 20; 62 +/- 1) sedentary, and premenopausal (n = 14; 30 +/- 1) and postmenopausal (n = 12; 58 +/- 1) endurance-exercise trained (distance runners). In the sedentary group, 24-h SBP and PP (Spacelabs ambulatory monitor 90207) were approximately 10 mmHg higher (P < 0.05) in the postmenopausal women than in the premenopausal controls; this was because of higher daytime and nighttime SBP and PP levels in the postmenopausal women. In contrast, 24-h, daytime and nighttime SBP and PP were not different with age in the endurance-trained women. SBP variability and SBP load (% of all recordings > 140 mmHg) generally were greater with age in the sedentary women (e.g., SBP load = 14 +/- 4 vs. 3 +/- 1%, P < 0.05) but not in the endurance-trained women. In the pooled population, 24-h SBP and PP were related to waist-to-hip ratio (measure of abdominal adiposity) (r = 0.48 and 0.49, respectively, P < 0.001) and carotid augmentation index (measure of arterial stiffness) (r = 0.43 and 0.53, P < 0.005). In the sedentary women, accounting for the influence of either of these factors eliminated the significant age-associated differences in 24-h SBP and PP (P > 0.3). Our results suggest that the elevations in 24-h SBP and PP with age in sedentary adult females may not occur in women who regularly perform endurance exercise. This appears to be related to the absence of age-associated increases in abdominal adiposity and arterial stiffness in the exercising women.

Dynamics of a harvested moose population in a variable environment

1.Population size, calves per female, female mean age and adult sex ratio of a moose (Alces alces) population in Vefsn, northern Norway were reconstructed from 1967 to 1993 using cohort analysis and catch‐at‐age data from 96% (6752) of all individuals harvested.2.The dynamics of the population were influenced mainly by density‐dependent harvesting, stochastic variation in climate and intrinsic variation in the age‐structure of the female segment of the population.3.A time delay in the assignment of hunting permits in relation to population size increased fluctuations in population size.4.Selective harvesting of calves and yearlings increased the mean age of adult females in the population, and, because fecundity in moose is strongly age‐specific, the number of calves per female concordantly increased. However, after years with high recruitment, the adult mean age decreased as large cohorts entered the adult age‐groups. This age‐structure effect generated cycles in the rate of recruitment to the population and fluctuations introduced time‐lags in the population dynamics.5.An inverse relationship between recruitment rate and population density, mediated by a density‐dependent decrease in female body condition, could potentially have constituted a regulatory mechanism in the dynamics of the population, but this effect was counteracted by a density‐dependent increase in the mean age of adult females.6.Stochastic variation in winter snow depth and summer temperature had delayed effects on recruitment rate and in turn population growth rate, apparently through effects on female body condition before conception.

Does reproductive investment change with age in tsetse flies, Glossina morsitans morsitans (Diptera: Glossinidae)?

1. Viviparous insects such as tsetse (Glossina spp.) provide unusual opportunities to compare age-related changes in the proportion of maternal resources transferred to offspring. 2. In laboratory populations of Glossina morsitans morsitans the survival of females was high for the first 60 days of adult life but declined rapidly thereafter. 3. Average longevity did not differ significantly between mated and unmated females (93·6 and 90 days, respectively). 4. Nutritional state in terms of fat content and residual dry mass did not decline with adult female age. 5. The fecundity of mated females was constant for the first 60 days of adult life and declined only slightly thereafter. 6. Offspring size did not change towards the end of the adult female lifespan and there was no evidence of an increase in the allocation of resources to reproduction in older females. 7. Results contrast with those obtained recently for vertebrates and may indicate that age-related changes in offspring size in Glossina are not adaptive, or that so few females reach old age under natural conditions that there is no selection for a strategy of terminal investment.

STEP TRAINING WITH AND WITHOUT EXTREMITY LOADING: EFFECT ON MUSCLE STRENGTH, BODY COMPOSITION, AND PSYCHOLOGICAL AFFECT

1126 The purpose of this study was to examine the effects of step training with and without light extremity loading on muscle strength, body composition, and psychological affect. Thirty-two healthy adult females (age: 21-51 years) were randomly assigned to exercise groups that trained with (n=16) or without(n=16) 0.68 kg/ankle attached and 1.36 kg/hand-held extremity loads while 12 subjects served as non-training control. Exercise training was conducted 3 times per week for 12 weeks. Individual sessions consisted of a warm-up, 30 minutes of step exercise (60-90% HRmax) using adjustable bench step platforms (15.2-25.4 cm in height), and a cool-down. Before and after training, elbow and knee flexion/extension, and shoulder abduction/adduction muscle strength (peak torque at 60 °/sec) was assessed by isokinetic dynamometry, body composition by hydrostatic weighing, and psychological affective states using the positive and negative affect schedule (Watson et al., 1988). Analysis of variance revealed a significant pre- to post-test decrease in body fat percentage and fat weight (p<0.05), and no change for isokinetic peak torque and psychological affect in exercise trained subjects. The incorporation of light extremity loads into the step training regimen had no independent influence on study outcomes (p>0.05). No significant pre- to post- test changes were noted for the non-training control group (p>0.05). These data indicate that 12 weeks of supervised step training, performed either with or without regular light extremity loading, can be effective in improving body composition but it does not alter isokinetic muscle strength and psychological affect in healthy adult females.

The relationship between the female menopause and serum sialic acid, a known cardiovascular risk factor.

Serum total sialic acid (SA) has recently been reported as a cardiovascular risk factor. The risk of cardiovascular disease increases after the menopause in females. However, there are little data looking at the relationship between serum SA and the menopause. Overall 92 females were studied. The women were divided into five groups: the first three groups were age-matched pre-menopausal (n=20), peri-menopausal (n=10) and post-menopausal women (n=20). In order to study serum SA changes with adult female age we also studied 14 young pre-menopausal women and 28 elderly women. There was no significance difference between the serum SA concentration in the age-matched pre-, peri- or post-menopausal women (62.7±10.4 mg/dl, 61.7±4.5 mg/dl, 62.9±7.0 mg/dl respectively). Furthermore, there was no significant difference between the serum SA in the “young” women (64.7±9.8 mg/dl) and that of the peri-, pre- or post-menopausal women. However, in the elderly women the serum SA was elevated (75.6±16.6 mg/dl) with P<0.05 for each comparison group. In conclusion, serum SA does not seem to change at the time of the female menopause although in elderly women (average age 75.6±16.6 years) it increases. The reason for this increase is not known and may merit further research.

Operational and Biological Factors Influencing Responses of Spider Mites (Acari: Tetranychidae) to Propargite by Using the Petri Dish-Potter Tower Method

A series of laboratory bioassays was done to determine the effects of various operational and biological factors on the responses of adult female twospotted spider mite, Tetranychus urticae Koch, and European red mite, Panonychus ulmi (Koch), to propargite when using the Petri dish—Potter tower method. The spray volume (1—5 ml) used to treat the petri dishes significantly influenced the responses of both species to propargite residues: a 5-ml spray volume was 6.7- and 4.7-fold more toxic than a 1-ml spray volume at the LC50 to twospotted spider mite and European red mite, respectively.To test the effectiveness of propargite residues over time, mites were exposed at intervals to treated petri dishes that were stored for up to 30 d at 4 ± 1oC. The toxicity of propargite remained constant throughout this period. When mites were retained in petri dishes in a manner that prevented contact with residues, no mortality of mites caused by the vapor action of propargite was detected at 23 and 30oC. However, the toxicity of propargite to mites in contact with residues increased 113- and 522-fold at the LC50 between 10 and 30oC for twospotted spider mite and European red mite, respectively. The age of adult females also influenced the response to propargite residues: 7-d-old twospotted spider mite females were 1.9-fold more tolerant than 1-d-old females at the LC50.The relevance of these findings to miticide bioassays using this method is discussed.

Obesity in Bahraini adults.

In this study the prevalence of obesity and the demographic factors associated with it were analysed on 290 adult Bahraini individuals, of whom 137 were males and 153 were females. The overweight and obesity prevalence rates, using the Body Mass Index (BMI) as a criterion, were 26% and 16% in males and 29% and 31% in females, respectively. The prevalence of underweight (BMI < 20) was 16.8% and 11.8% in the males and females respectively. The mean body fat percentage of females, calculated from the skinfold measurements, was 35%; the fat percentage of males was 18.6%. Bahraini women had greater fat deposition in the subscapular region than the amount reported for American women. Females and males living in urban areas had a greater tendency to be obese than those residing in rural areas. Marriage, ownership of a car as well as a large family ( > 7 members) were positively associated with obesity; unmarried women were more likely to be underweight than married women. The educational level was not associated with obesity in either the males or females. The age of adult females was not found to be associated with obesity, whereas in males the incidence of obesity was more frequent among those who were 50 years of age and above than under 50 years of age. Family monthly income was not associated with the incidence of obesity. The high prevalence of overweight and obesity in the women reported in this study and the difference in the distribution of body fat suggest that genetics may be a determinant factor of this disorder in Bahrainis but certainly social factors are also important.

Persistent organochlorines in beluga whales ( Delphinapterus leucas) from the St Lawrence River estuary-I. Concentrations and patterns of specific PCBs, chlorinated pesticides and polychlorinated dibenzo- p-dioxins and dibenzofurans

Blubber samples from beluga whales ( Delphinapterus leucas) in the St Lawrence River estuary were analysed for PCB congeners (ortho- and non-ortho-substituted) and other persistent organochlorines as well as chlorinated dibenzo-dioxins/furans (PCDD/Fs). Major individual components (mean concentrations > 1 μg g −1) were 4,4′-DDE, -DDD and -DDT, T12 (a toxaphene-related compound), trans-nonachlor, oxychlordane, mirex, HCB, tris( p-chlorophenyl) methane and dieldrin. Concentrations of ∑PCBs (8.3–412 μg g −1), ∑DDT (3.36–389 μg g −1) and mirex (0.18–6.8 μg g −1) were particularly elevated relative to other odontocetes in Canadian waters. ∑DDT, PCBs (as Aroclor), mirex and T12 concentrations were positively correlated with age of adult females (> 10 years) but only weakly, or not significantly, correlated with age of adult males. PCDD/Fs were present at low ng kg −1 levels and consisted mainly of penta- and hexachlorofurans, and hepta- and octachlorodioxin. CB126 (3,3′,4,4′,5-PCB) was the most prominent non-ortho-substituted PCB congener in beluga blubber. Total TCDD toxic equivalents averaged 330 ng kg −1 in females and 1400 ng kg −1 in males and were dominated by CB126, and the mono-ortho-substituted congeners CB105 and CB118. Biomagnification factors (BMFs) for mirex and ∑PCB from fish to beluga ranged from 11 to 16, and were similar to BMFs in Arctic animals, indicating that elevated levels in St Lawrence animals are a consequence of relatively high levels of recalcitrant organochlorines in prey of the beluga in the St Lawrence river system.

Ethnic differences in bone density in female South African nurses

In the United States, the higher prevalence of osteoporosis and the higher incidence of fractures in whites than in blacks may be attributed to the finding of lower bone density (BD) in both white children and adults. In South Africa, osteoporosis and fractures also occur more frequently in whites than in blacks. Appendicular BD has been found to be similar in black and white children in South Africa, but there is little information available on BD of adults in South Africa. This cross-sectional study aimed to assess changes in BD with age in adult females in South Africa and to assess possible differences in peak BD and in the rate of postmenopausal bone loss between blacks and whites. Data for 180 black and 184 white female nurses aged 20-64 years were analyzed. The distal radius bone density (RBD) was measured by single photon absorptiometry. The lumbar spine bone density (SBD) and the femur bone density (FBD) were measured by dual-energy X-ray absorptiometry. Blacks were shorter than whites (p = 0.0001), and blacks' weight, body mass index, and skinfold thickness increased with age. Peak SBD and RBD were similar in blacks and whites, but peak FBD was higher in blacks (p = 0.0001). This ethnic difference in peak FBD became apparent in the fourth decade. Peak FBD was similar in black and white subjects with normal body mass indices (p = 0.09), but in overweight subjects peak FBD was higher in blacks than in whites (p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)