Determining the age of adult wild dogs (Canis lupus dingo, C-l. domesticus and their hybrids). I. Pulp cavity: tooth width ratios

In order to determine the age of adult wild dogs, we compared two methods ( that of Thomson and Rose (TR method) and that of Knowlton and Whittemore (KW method)) of measuring and calculating pulp cavity : tooth width ratios on upper and lower canine teeth from 68 mixed-sex, known-age wild dogs of 9 months to 13 years of age reared at two localities. Although significant relationships ( P = 0.0001) were found between age and pulp cavity ratios by both methods, the TR ratio calculation and measurement showed heteroscedasity in error variance whereas the KW ratios had a more stable error variance and were normally distributed. The KW method also found significant differences between pulp cavity ratios between teeth of the upper and lower jaws ( P < 0.0001) and sex ( P = 0.01) but not geographic origin ( P = 0.1). Regressions and formulae for fitted curves are presented separately for male and female wild dogs. Males show greater variability in pulp cavity decrements with age than do females, suggesting a physiological difference between the sexes. We conclude that the KW method of using pulp cavity as a proportion of tooth width, measured 15 mm from the root tip and averaged over both upper canines, is the more accurate method of estimating the age of adult wild dogs.

Height, age at menarche, and risk of epithelial ovarian cancer

Objective: We hypothesized that the hormonal changes of adolescence influence ovarian cancer risk particularly in younger women. We investigated this possibility by examining the relationship between ovarian cancer and adult height and age at menarche as both factors reflect pubertal hormonal levels. Methods: Participants were a population-based sample of women with incident ovarian cancer (n = 794) and control women randomly selected from the Australian Electoral Roll (n = 855). The women provided comprehensive reproductive and lifestyle data during a standard interview. Results: Although neither height nor age at menarche was significantly related to the risk of ovarian cancer overall, increasing height was associated with increasing risk of the subgroup of mucinous borderline ovarian cancer (odds ratio, 5.3; 95% confidence interval, 1.5-19.1 for women 175 cm compared with women < 160 cm, P-trend = 0.02). Similarly, later age at menarche was associated with increasing risk of mucinous borderline cancers (odds ratio, 3.8; 95% confidence interval, 1.3-11.4 for those with age at menarche >= 44 years compared with those < 12 years, P-trend = 0.003). Women with mucinous borderline cancers were significantly younger than the women diagnosed with invasive cancers (mean 44 versus 57 years; P < 0.0001). Conclusions: Development of mucinous borderline ovarian cancers, predominantly diagnosed in women ages under 50 years, seems to be associated with age at menarche and attained adult height. These results are consistent with our original hypothesis that pubertal levels of reproductive hormones and insulin-like growth factor-I influence ovarian cancer risk in younger women.

Rethinking the "diseases of affluence" paradigm: Global patterns of nutritional risks in relation to economic development

Background Cardiovascular diseases and their nutritional risk factors-including overweight and obesity, elevated blood pressure, and cholesterol-are among the leading causes of global mortality and morbidity, and have been predicted to rise with economic development. Methods and Findings We examined age-standardized mean population levels of body mass index (BMI), systolic blood pressure, and total cholesterol in relation to national income, food share of household expenditure, and urbanization in a cross-country analysis. Data were from a total of over 100 countries and were obtained from systematic reviews of published literature, and from national and international health agencies. BMI and cholesterol increased rapidly in relation to national income, then flattened, and eventually declined. BMI increased most rapidly until an income of about I$5,000 (international dollars) and peaked at about I$12,500 for females and I$17,000 for males. Cholesterol's point of inflection and peak were at higher income levels than those of BMI (about I$8,000 and I$18,000, respectively). There was an inverse relationship between BMI/cholesterol and the food share of household expenditure, and a positive relationship with proportion of population in urban areas. Mean population blood pressure was not correlated or only weakly correlated with the economic factors considered, or with cholesterol and BMI. Conclusions When considered together with evidence on shifts in income-risk relationships within developed countries, the results indicate that cardiovascular disease risks are expected to systematically shift to low-income and middle-income countries and, together with the persistent burden of infectious diseases, further increase global health inequalities. Preventing obesity should be a priority from early stages of economic development, accompanied by population-level and personal interventions for blood pressure and cholesterol.

Cadmium-induced nephropathy in the development of high blood pressure

In recognition of a central role of the kidney in long-term blood pressure control, we undertook an in-depth analysis of the relationship between blood pressure and kidney damage caused by environmental exposure to the common pollutants cadmium and lead. The subjects were 200 healthy Thais, 16 and 60 years of age (100 female non-smokers, 53 male non-smokers, and 47 male smokers). None of these subjects had been exposed to Cd or Pb in the workplace and their urinary Cd concentrations ranged from 0.4 to 37 nM, whereas their urinary Pb concentrations ranged from 0.1 to 30 nM. The prevalence of high blood pressure was 2%, 8% and 19%, respectively in subjects with low, average and high Cd-burden (linear trend chi(2) = 6.4, P = 0.01). Multiple regression analysis revealed a significant positive association between Cd-burden and blood pressure in male nonsmokers (adjusted beta = 0.31, P = 0.02) and an inverse association between blood pressure and urinary Pb excretion rate in male smokers (adjusted beta = -0.38, P = 0.005). Associations between Cd-burden and nephropathies were evidenced by increases in urinary excretion of beta 2-microglobutin (P = 0.02) and N-acetyl-beta-D-glucosaminidase (P = 0.005) in subjects with high Cd-burden, compared with the subjects with average Cd-burden. In addition, an association between Cd-related nephropathy and high blood pressure was evidenced by a 20% increase in the prevalence of high blood pressure in people with NAG-uria (linear trend chi(2) = 4.3, P = 0.04). Our present study provides first evidence for a possible link between renal tubular damage and dysfunction caused by environmental Cd exposure and increased risk of high blood pressure. (c) 2005 Elsevier Ireland Ltd. All rights reserved.

Testicular development of Zebu bulls after chronic treatment with a gonadotropin-releasing hormone agonist

The objective was to compare testis characteristics of Zebu bulls treated with the GnRH agonist, deslorelin, at different times and for different durations during their development. An additional objective was to determine the usefulness of a stain for the transcription factor GATA-binding protein 4 (GATA-4) as a specific marker for Sertoli cell nuclei in cattle. Bulls (54) were allocated to nine groups (n = 6) and received s.c. deslorelin implants as follows: G1 = from birth to 3 mo of age; G2 = from 3 to 6 mo; G3 = from 6 to 9 mo; G4 = from 9 to 12 mo; G5 = from birth to 15 mo; G6 = from 3 to 15 mo; G7 = from 6 to 15 mo; G8 = from 12 to 15 mo; and G9 (control) = no implant. Bulls were castrated at 19 mo of age. Paraffin sections (10 mu m) were subjected to quantitative morphometry and GATA-4 immunohistochemistry. At castration, all bulls in the control group (6/6) had attained puberty (scrotal circumference ! 28 cm), whereas a smaller proportion (P < 0.05) had reached puberty in G2 (2/5) and G6 (1/ 6). Bulls in G2 and G6 also had a lesser (P < 0.05) testis weight compared with the control group. Total volume of seminiferous epithelium and total daily sperm production in G2 and G6 were only half that observed in the control group. Spermatids were observed in less than 50% of seminiferous tubules in G2, G6, and G7 compared with 82% in the control group (P < 0.05). Staining for GATA-4 was specific for and abundant in the Sertoli cell nucleus in both pre- and postpubertal bulls, and no other cell nucleus inside the seminiferous tubule was positive for GATA-4. Total number of Sertoli cells was not affected by treatment (P = 0.45), but nuclear volume was smaller in G2 and G6 (P < 0.05) compared with the control group. In conclusion, treatment of Zebu bulls with deslorelin had no apparent beneficial effect on testis development and delayed puberty when treatment was initiated at 3 mo of age. Staining for GATA-4 was a useful method for identifying and quantifying Sertoli cell nuclei in both pre- and postpubertal bulls.

Mind and body: Concepts of human cognition, physiology and false belief in children with autism or typical development

This study examined theory of mind (ToM) and concepts of human biology (eyes, heart, brain, lungs and mind) in a sample of 67 children, including 25 high functioning children with autism (age 6-13), plus age-matched and preschool comparison groups. Contrary to Baron-Cohen [1989, Journal of Autism and Developmental Disorders, 19(4), 579-600], most children with autism correctly understood the functions of the brain (84%) and the mind (64%). Their explanations were predominantly mentalistic. They outperformed typically developing preschoolers in understanding inner physiological (heart, lungs) and cognitive (brain, mind) systems, and scored as high as age-matched typical children. Yet, in line with much previous ToM research, most children with autism (60%) failed false belief, and their ToM performance was unrelated to their understanding of. human biology. Results were discussed in relation to neurobiological and social-experiential accounts of the ToM deficit in autism.

Family structure and age at menarche: A children-of-twins approach

Girls who grow up in households with an unrelated adult male reach menarche earlier than peers, a finding hypothesized to be an evolutionary strategy for families under stress. The authors tested the alternative hypothesis that nonrandom selection into stepfathering due to shared environmental and/or genetic predispositions creates a spurious relation between stepfathering and early menarche. Using the unique controls for genetic and shared environmental experiences offered by the children-of-twins design, the authors found that cousins discordant for stepfathering did not differ in age of menarche. Moreover, controlling for mother's age of menarche eliminated differences in menarcheal age associated with stepfathering in unrelated girls. These findings strongly suggest selection, and not causation, accounts for the relationship between stepfathering and early menarche.

Development of a dosage strategy in patients receiving enoxaparin by continuous intravenous infusion using modelling and simulation

Aim To develop an appropriate dosing strategy for continuous intravenous infusions (CII) of enoxaparin by minimizing the percentage of steady-state anti-Xa concentration (C-ss) outside the therapeutic range of 0.5-1.2 IU ml(-1). Methods A nonlinear mixed effects model was developed with NONMEM (R) for 48 adult patients who received CII of enoxaparin with infusion durations that ranged from 8 to 894 h at rates between 100 and 1600 IU h(-1). Three hundred and sixty-three anti-Xa concentration measurements were available from patients who received CII. These were combined with 309 anti-Xa concentrations from 35 patients who received subcutaneous enoxaparin. The effects of age, body size, height, sex, creatinine clearance (CrCL) and patient location [intensive care unit (ICU) or general medical unit] on pharmacokinetic (PK) parameters were evaluated. Monte Carlo simulations were used to (i) evaluate covariate effects on C-ss and (ii) compare the impact of different infusion rates on predicted C-ss. The best dose was selected based on the highest probability that the C-ss achieved would lie within the therapeutic range. Results A two-compartment linear model with additive and proportional residual error for general medical unit patients and only a proportional error for patients in ICU provided the best description of the data. Both CrCL and weight were found to affect significantly clearance and volume of distribution of the central compartment, respectively. Simulations suggested that the best doses for patients in the ICU setting were 50 IU kg(-1) per 12 h (4.2 IU kg(-1) h(-1)) if CrCL < 30 ml min(-1); 60 IU kg(-1) per 12 h (5.0 IU kg(-1) h(-1)) if CrCL was 30-50 ml min(-1); and 70 IU kg(-1) per 12 h (5.8 IU kg(-1) h(-1)) if CrCL > 50 ml min(-1). The best doses for patients in the general medical unit were 60 IU kg(-1) per 12 h (5.0 IU kg(-1) h(-1)) if CrCL < 30 ml min(-1); 70 IU kg(-1) per 12 h (5.8 IU kg(-1) h(-1)) if CrCL was 30-50 ml min(-1); and 100 IU kg(-1) per 12 h (8.3 IU kg(-1) h(-1)) if CrCL > 50 ml min(-1). These best doses were selected based on providing the lowest equal probability of either being above or below the therapeutic range and the highest probability that the C-ss achieved would lie within the therapeutic range. Conclusion The dose of enoxaparin should be individualized to the patients' renal function and weight. There is some evidence to support slightly lower doses of CII enoxaparin in patients in the ICU setting.

Development of an animal repellent - selection, efficacy and presentation

Under some circumstances it may be desirable to repel herbivorous pests (e. g. goats and wallabies) from plants (e. g. horticultural or forestry seedlings) rather than to kill them. These circumstances may include using these animals as a resource at a later time, and there may also be welfare, public perception or legislative issues where repelling animals from particular plants or area is preferable to killing them. The first experiment tested the efficacy of 5 different materials (tiger fecal extract, maggot brew-the liquid exudate from a flyblown goat, capsaicin, dog urine, and burnt goat hair, skin and carcass+fat) to repel groups of goats in a feedlot pen from 1 trough of feed when another trough of feed was available to them to eat. Each repellent was tested on 5 groups of mixed age female goats for periods of 3 days. All 5 groups were exposed to the 5 repellents. Both tiger fecal extract and maggot brew reduced intake of feed from the 'protected' feed trough and significantly (P < 0.05) delayed 'normal' feeding behaviour by more than 5 h from that trough. The repellents became less effective with repeated use even with different groups of goats. The reduction in effectiveness was indicated by higher intakes of feed and earlier feeding from the protected trough. This habituation to the repellents, where the effectiveness is reduced with repeated exposure, is of concern. In the second experiment, we selected the most effective repellent (tiger fecal extract) and tested its efficacy under similar conditions, after the repellent had been mixed with a carrier (bentonite) in an endeavour to increase the duration of its effectiveness. This repellent was significantly more effective in repelling groups of 3 goats in a feedlot pen from 1 trough of feed for 3 days, when another trough of feed was available to them to eat.

Does nephron number matter in the development of kidney disease?

The total number of nephrons in normal human kidneys varies over a 10-fold range. This variation in total nephron number leads us to question whether low nephron number increases the risk of renal disease in adulthood. This review considers the available evidence in humans linking low nephron number/reduced nephron endowment and the susceptibility to renal disease. Total nephron number in humans has been directly correlated with birth weight and inversely correlated with age, mean glomerular volume, and hypertension. Low nephron number may be the result of suboptimal nephrogenesis during kidney development and/or loss of nephrons once nephrogenesis has been completed. Low nephron number is frequently, but not always, associated with hypertrophy of remaining glomeruli. This compensatory hypertrophy has also been associated with a greater susceptibility for kidney disease. Three human studies have reported reduced nelphron number in subjects with a history of hypertension. This correlation has been observed in White Europeans, White Americans (but not African Americans) and Australian Aborigines. Studies in additional populations are required, as well as a greater understanding of the fetal environmental and genetic determinants of low nephron number.

Relationships of activity and sugar drink intake on fat mass development in youths

Purpose: To determine whether a significant relationship exists between fat mass (FM) development and physical activity (PA) and/or sugar-sweetened drink (SD) consumption in healthy boys and girls aged 8-19 yr. Methods: A total of 105 males and 103 females were assessed during childhood and adolescence for a maximum of 7 yr and a median of 5 yr. Height was measured biannually. Fat-free mass (FFM) and FM were assessed annually by dual x-ray absorptiometry (DXA). PA was evaluated two to three times annually using the PAQ-C/A. Energy intake and SD were assessed using a 24-h dietary intake questionnaire also completed two to three times per year. Years from peak height velocity were used as a biological maturity age indicator. Multilevel random effects models were used to test the relationship. Results: When controlling for maturation, FFM, and energy intake adjusted for SD, PA level was negatively related to FM development in males (P < 0.05) but not in females (P > 0.05). In contrast, there was no relationship between SD and FM development of males or females (P > 0.05). There was also no interaction effect between SD and PA (P > 0.05) with FM development. Conclusion: This finding tends support to the idea that increasing PA in male youths aids in the control of FM development. Models employed showed no relationship between SD and FM in either gender.

Comparison of growth and development of the red-tailed phascogale (Phascogale calura) in three captive colonies

The red-tailed phascogale ( Phascogale calura) is an endangered dasyurid species that has recently been brought into captivity in an effort to increase numbers before release back into the wild. As part of investigations into the reproductive biology of the species, information on the growth and development of young was collected throughout lactation from litters raised in three separate colonies. Growth curves for aging young throughout lactation and a timetable of developmental changes were constructed. While two colonies, with fourth- and fifth-generation captive animals, showed no significant difference in growth, animals from a third colony that had been wild caught before breeding displayed a slower rate of growth from 34 days of age. The pattern of development resembled that of other dasyurids, with young left in the nest from 44 days of age, fully furred by 78 days and weaned between 90 and 110 days. Captive phascogales invest heavily in their young, with litters weighing 380 +/- 67% of maternal bodyweight at weaning.

Virtual teams and group member dissimilarity - Consequences for the development of trust

The consequences of demographic dissimilarity for group trust in work teams was examined in a virtual (computer-mediated) and a face-to-face (FTF) environment. Demographic dissimilarity (based on age, gender, country of birth, enrolled degree) was predicted to be negatively associated with group trust in the FTF environment but not in the computer-mediated environment. Participants worked in small groups on a creative task for 3 consecutive days. In the computer-mediated environment, participants worked on the task for an hour per day. In the FTF environment, participants worked on the task for 20 minutes per day. Partial support was found for the effectiveness of computer-mediated groups in reducing the negative consequences of dissimilarity. Age dissimilarity was negatively related to trust in FTF groups but not in computer-mediated groups. Birthplace dissimilarity was positively related to trust in computer-mediated groups. Implications for the successful management of virtual teams are discussed.

Employment services in an age of e-government

The increasing use of information and communications technologies among government departments and non-government agencies has fundamentally changed the implementation of employment services policy in Australia. The administrative arrangements for governing unemployment and unemployed people are now constituted by a complex contractual interplay between government departments as ‘purchasers’ and a range of small and large private organizations as ‘providers’. Assessing, tracking and monitoring the activities of unemployed people through the various parts of the employment services system has been made possible by developments in information technology and tailored computer programs. Consequently, the discretionary capacity that is traditionally associated with ‘street-level bureaucracy’ has been partly transformed into more prescriptive forms of ‘screen-level bureaucracy’. The knowledge embedded in these new computer-based technologies is considered superior because it is based on ‘objective calculations’, rather than subjective assessments of individual employees. The relationship between the sociopolitical context of unemployment policy and emerging forms of e-government is explored using illustrative findings from a qualitative pilot study undertaken in two Australian sites. The findings suggest that some of the new technologies in the employment services system are welcomed, while other applications are experienced as contradictory to the aims of delivering a personalized and respectful service.