217 resultados para Multiple abstraction levels


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Reproductive data from southern Queensland indicate that vitellogenesis in female Chelonia mydas takes approximately 8 months and is followed by a migration to a breeding area. At Heron Island, females lay multiple clutches over approximately 3 months. To investigate how females mobilise and store lipid during the breeding season we collected plasma, yolk, and fat tissue samples from females at a variety of stages during the nesting season. In breeding females, concentrations of plasma triglyceride increased seasonally. They reached peak concentrations during vitellogenesis and courtship, remained high throughout the nesting season, and then declined to a nadir after the last clutch. Plasma protein concentration increased throughout the breeding season, peaking following the last clutch for the season. Yolk lipids were highest during courtship and were similar throughout the nesting season, suggesting that uptake of lipid by ovarian follicles is completed prior to the beginning of the nesting season. Plasma triglyceride decreases in females with prolonged periods of unsuccessful nesting, and total lipid levels in adipose tissue and follicle yolks were significantly lower in atretic females. It appears that: (1) endogenous energy reserves can be reduced by stochastic environmental events (such as those reducing nesting success), and (2) a metabolic shift signalling the end of the nesting season is characterised by a drop in plasma triglycerides and slight increase in total plasma protein.

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Optimised gradient reversed-phase high-performance liquid chromatography electrospray ionisation mass spectrometry (LC/MS) methods, in combination with a [H-3]-brevetoxin binding assay (RLB), revealed multiple ciguatoxins in a partially purified extract of a highly toxic Lutjanus sebae (red emperor) from the Indian Ocean. Two major ciguatoxins of 1140.6 Da (I-CTX-1 and -2) and two minor ciguatoxins of 1156.6 Da (I-CTX-3 and -4) were identified. Accurate mass analysis revealed that I-CTX-1 and -2 and Caribbean C-CTX-1 had indistinguishable masses (1140.6316 Da, at 0.44 ppm resolution). Toxicity estimated from LC/MS/RLB responses indicated that I-CTX-1 and -2 were both similar to 60% the potency of Pacific ciguatoxin-1 (P-CTX-1). In contrast to ciguatoxins of the Pacific where the more oxidised ciguatoxins are more potent, I-CTX-3 and -4 were similar to 20% of P-CTX-1 potency. Interconversion in dilute acid or on storage, typical of spiroketal and hemiketal functionality found in P-CTXs and C-CTXs, respectively, was not observed to occur between I-CTX-1 and -2. The ratio of CTX-1 and -2 varied depending on the fish extract being analysed. These results suggest that I-CTX-1 and -2 may arise from separate dinoflagellate precursors that may be oxidatively biotransformed to I-CTX-3 and -4 in fish. (C) 2002 Published by Elsevier Science Ltd.

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Research has indicated a weak relationship between the degree of physical problems and quality of life in patients with chronic obstructive pulmonary disease (COPD). The importance of adaptive psychological functioning to maintain optimum quality of life has long been recognized, but there is a lack of empirical evidence concerning the nature of psychological factors involved in adjustment to COPD. Ninety-two males completed questionnaires to determine their coping strategies, levels of self-efficacy of symptom management and social support. Adjustment was measured in terms of depression, anxiety and quality of life. Symptom severity, socioeconomic status, duration of disease and age, which have been demonstrated to be of consequence in COPD, were used as control variables in hierarchical multiple regression analyses. Higher levels of catastrophic withdrawal coping strategies and lower levels of self-efficacy of symptom management were associated with higher levels of depression, anxiety and a reduced quality of life. Higher levels of positive social support were linked to lower levels of depression and anxiety, while higher levels of negative social support were linked to higher levels of depression and anxiety. To maximize quality of life in patients with chronic obstructive pulmonary disease, psychological factors need to be carefully assessed and addressed.

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Three experiments are reported which examine the effects of consensus information on majority and minority influence. In all experiments two levels of consensus difference were examined; large (82% versus 18%) and small (52% versus 48%). Experiment 1 showed that a majority source had more influence than a minority source, irrespective of consensus level. Experiment 2 examined the cause of this effect by presenting only the source label ('majority' versus 'minority'), only the consensus information (percentages) or both. The superior influence of the majority was again found when either (a) both source label and consensus information were given (replicating Experiment 1) and (b) only consensus information was given, but not when (c) only the source label was given. The results showed majority influence was due to the consensus information indicating more than 50% of the population supported that position. Experiment 3 also manipulated message quality (strong versus weak arguments) to identify whether systematic processing had occurred. Message quality only had an impact with the minority of 18%. These studies show that consensus information has different effects' for majority and minority influence. For majority influence, having over 50% support is sufficient to cause compliance while for a minority there are advantages to being numerically small, in terms of leading to detailed processing of its message. Copyright (C) 2002 John Wiley Sons, Ltd.

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Fetal alcohol syndrome (FAS) is the leading cause of mental retardation in western society. We investigated possible changes in glutamate receptor levels in neonatal animals following ethanol exposure using radioligand binding and western blot analysis. We used a vapor chamber to administer ethanol to neonatal Wistar rats 3 h a day from postnatal day (PND) 4-9. A separation control group was separated from their mothers for the same time and duration as the vapor treatment, while a normal control group was left to develop normally. Daily ethanol administrations resulted in decreased brain weight and body weight, as well as microencephaly (decreased brain:body weight ratio). Neither the affinity nor maximum binding of [H-3]MK-801 (dizoclipine maleate) in the cortex of PND10 rats differed between treatment groups. Western blot analysis also failed to reveal any changes in NMDAR1, NMDAR2A, or NMDAR2B receptor levels. In contrast, the AMPA receptor subunit GluR1 was greatly reduced in vapor-treated pups compared with control pups, as revealed by western blot analysis. A similar reduction was found in westerns with an antibody recognizing the GluR2 and 4 subunits. These results indicate that ethanol reduces AMPA rather than NMDA receptors in the developing neocortex, possibly by blocking NMDA receptors during development. (C) 2002 Elsevier Science B.V. All rights reserved.

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We report a case of a patient with the triad of retinoblastoma, dysplastic naevus syndrome (DNS) and multiple cutaneous melanomas. The combination of retinoblastoma and DNS is a significant risk factor for the development of cutaneous melanoma. This risk extends to family members. We recommend that survivors of (inherited) retinoblastoma and their relatives are closely screened for the presence of dysplastic naevi. (C) 2002 Lippincott Williams Wilkins.

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Objective: To measure the cost-effectiveness of cholesterol-lowering therapy with pravastatin in patients with established ischaemic heart disease and average baseline cholesterol levels. Design: Prospective economic evaluation within a double-blind randomised trial (Long-Term Intervention with Pravastatin in Ischaemic Disease [LIPID]), in which patients with a history of unstable angina or previous myocardial infarction were randomised to receive 40 mg of pravastatin daily or matching placebo. Patients and setting: 9014 patients aged 35-75 years from 85 centres in Australia and New Zealand, recruited from June 1990 to December 1992. Main outcome measures: Cost per death averted, cost per life-year gained, and cost per quality-adjusted life-year gained, calculated from measures of hospitalisations, medication use, outpatient visits, and quality of life. Results: The LIPID trial showed a 22% relative reduction in all-cause mortality (P < 0.001). Over a mean follow-up of 6 years, hospital admissions for coronary heart disease and coronary revascularisation were reduced by about 20%. Over this period, pravastatin cost $A4913 per patient, but reduced total hospitalisation costs by $A1385 per patient and other long-term medication costs by $A360 per patient. In a subsample of patients, average quality of life was 0.98 (where 0 = dead and 1 = normal good health); the treatment groups were not significantly different. The absolute reduction in all-cause mortality was 3.0% (95% CI, 1.6%-4.4%), and the incremental cost was $3246 per patient, resulting in a cost per life saved of $107730 (95% Cl, $68626-$209881) within the study period. Extrapolating long-term survival from the placebo group, the undiscounted cost per life-year saved was $7695 (and $10 938 with costs and life-years discounted at an annual rate of 5%). Conclusions: Pravastatin therapy for patients with a history of myocardial infarction or unstable angina and average cholesterol levels reduces all-cause mortality and appears cost effective compared with accepted treatments in high-income countries.

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The moth larva, Doratifera stenosa (Lepidoptera: Limacodidae), was observed feeding voraciously in great numbers on mature leaves of Rhizophora stylosa in mangroves at Port Curtis in Central Queensland, NE Australia. This behaviour was considered unusual since mangroves, and the Rhizophora species in particular, reportedly harbour few herbivores and have relatively low levels of herbivory, less than 10%. During a two year period (1996-1998), larvae were observed consuming around 30-40% of leaves in the canopy each year, and the mangroves appeared able to sustain these high levels of herbivory. The impact on trees was assessed in conjunction with a study of the herbivore, its behaviour and life history, in an attempt to explain the occurrence. Larvae were 1-2 cm in length, bright green and gregarious, with numerous small, stinging hairs along their upper bodies. Feeding was in small cohort groups of 5-70 individuals that broke up immediately prior to each moult after which they regrouped in much larger numbers of mixed cohorts to form single-file processions across branches, stems and prop roots. In this way, they moved to neighbouring trees with less affected foliage. One of the outstanding characteristics of this herbivore was its ability to desist from killing host trees although it appeared quite capable of doing so had it remained on individual trees. By moving from tree to tree, the herbivore was able to heavily crop Rhizophora foliage in an apparently sustainable manner. These findings demonstrate the role and importance of foliar herbivory in severely affected forests and how such instances best not be ignored or treated as curiosities in future assessments of herbivory and forest turnover in mangrove ecosystems.

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The aim of this study was to assess the variation between neuropathologists in the diagnosis of common dementia syndromes when multiple published protocols are applied. Fourteen out of 18 Australian neuropathologists participated in diagnosing 20 cases (16 cases of dementia, 4 age-matched controls) using consensus diagnostic methods. Diagnostic criteria, clinical synopses and slides from multiple brain regions were sent to participants who were asked for case diagnoses. Diagnostic sensitivity, specificity, predictive value, accuracy and variability were determined using percentage agreement and kappa statistics. Using CERAD criteria, there was a high inter-rater agreement for cases with probable and definite Alzheimer's disease but low agreement for cases with possible Alzheimer's disease. Braak staging and the application of criteria for dementia with Lewy bodies also resulted in high inter-rater agreement. There was poor agreement for the diagnosis of frontotemporal dementia and for identifying small vessel disease. Participants rarely diagnosed more than one disease in any case. To improve efficiency when applying multiple diagnostic criteria, several simplifications were proposed and tested on 5 of the original 210 cases. Inter-rater reliability for the diagnosis of Alzheimer's disease and dementia with Lewy bodies significantly improved. Further development of simple and accurate methods to identify small vessel lesions and diagnose frontotemporal dementia is warranted.

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The purpose of this study was to determine the pharmacokinetics of [C-14]diclofenac, [C-14]salicylate and [H-3]clonidine using a single pass rat head perfusion preparation. The head was perfused with 3-[N-morpholino] propane-sulfonic acid-buffered Ringer's solution. Tc-99m-red blood cells and a drug were injected in a bolus into the internal carotid artery and collected from the posterior facial vein over 28 min. A two-barrier stochastic organ model was used to estimate the statistical moments of the solutes. Plasma, interstitial and cellular distribution volumes for the solutes ranged from 1.0 mL (diclofenac) to 1.6 mL (salicylate), 2.0 mL (diclofenac) to 4.2 mL (water) and 3.9 mL (salicylate) to 20.9 mL (diclofenac), respectively. A comparison of these volumes to water indicated some exclusion of the drugs from the interstitial space and salicylate from the cellular space. Permeability-surface area (PS) products calculated from plasma to interstitial fluid permeation clearances (CLPI) (range 0.02-0.40 mL s(-1)) and fractions of solute unbound in the perfusate were in the order: diclofenac>salicylate >clonidine>sucrose (from 41.8 to 0.10 mL s(-1)). The slow efflux of diclofenac, compared with clonidine and salicylate, may be related to its low average unbound fraction in the cells. This work accounts for the tail of disposition curves in describing pharmacokinetics in the head.

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OBJECTIVE - To assess the timing of fetal growth spurt among pre-existing diabetic pregnancies (types 1 and 2) and its relationship with diabetic control. To correlate fetal growth acceleration with factors that might influence fetal growth. RESEARCH DESIGN AND METHODS - This retrospective study involved all pregestational diabetic pregnancies delivered at a tertiary obstetric hospital in Australia between 1 January 1994 and 31 December 1999. Pregnancies with major congenital fetal anomalies, multiple pregnancies, small-for-gestational-age pregnancies (90th centile for gestation) were compared with babies with normal birth weights. RESULTS- A total of 101 diabetic pregnancies were included. Diabetic mothers, who had LGA babies, had significantly higher prepregnancy body weight and BMI (P < 0.05). There were no differences in maternal age or parity among the two groups. There were also no differences in the first-, second-, and third-trimester HbA(1c) levels between the two groups. The abdominal circumference z-scores were significantly higher for LGA babies from 18 weeks and thereafter. The differences increased progressively as the gestation advanced. Maximum difference was noted in the third trimester (30-38 weeks). CONCLUSIONS - Fetal growth acceleration in LGA fetuses of diabetic mothers starts in the second trimester, from as early as 18 weeks. In this study, glucose control did not appear to have a direct effect on the incidence of LGA babies, and such observation might result from the effects of other confounding factors.

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Based on a cognitive-social learning model of alcohol use, it was hypothesised that women with both alcohol and relationship problems would endorse more positive expectations of the effects of alcohol consumption on their relationship and would report lower relational efficacy than women without relationship or alcohol problems. Measures of relationship-referent alcohol expectancies and relational efficacy were completed by 174 married women with both alcohol and relationship problems (n = 20), alcohol problems alone (it = 26), relationship problems alone (n = 30), or neither problem (n = 98). Women without either alcohol or relationship problems strongly rejected expectations of enhanced relationship functioning (e.g., enhanced intimacy, increased emotional expression) following alcohol consumption, whereas women with both alcohol and relationship problems were ambivalent about these positive expectations. Women with both problems also reported lower relational efficacy than the other groups of women. Negative expectations about the effect of alcohol consumption on relationships in women with low relational efficacy may inhibit harmful drinking. (C) 2002 Elsevier Science Ltd. All rights reserved.

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To determine which species and populations of Anopheles transmit malaria in any given situation, immunological assays for malaria sporozoite antigen can replace traditional microscopical examination of freshly dissected Anopheles. We developed a wicking assay for use with mosquitoes that identifies the presence or absence of specific peptide epitopes of circumsporozoite (CS) protein of Plasmodium falciparum and two strains of Plasmodium vivax (variants 210 and 247). The resulting assay (VecTest(TM) Malaria) is a rapid, one-step procedure using a 'dipstick' test strip capable of detecting and distinguishing between P. falciparum and P. vivax infections in mosquitoes. The objective of the present study was to test the efficacy, sensitivity, stability and field-user acceptability of this wicking dipstick assay. In collaboration with 16 test centres world-wide, we evaluated more than 40 000 units of this assay, comparing it to the standard CS ELISA. The 'VecTest(TM) Malaria' was found to show 92% sensitivity and 98.1% specificity, with 97.8% accuracy overall. In accelerated storage tests, the dipsticks remained stable for >15 weeks in dry conditions up to 45degreesC and in humid conditions up to 37degreesC. Evidently, this quick and easy dipstick test performs at an acceptable level of reliability and offers practical advantages for field workers needing to make rapid surveys of malaria vectors.