105 research outputs found
Telemetry tails: a practical method for attaching animal-borne devices to small vertebrates in the field
Context. Continued miniaturisation of tracking technology increases its utility in animal applications. However, species morphology often dictates the type of animal-borne device (ABD) that can be used, and how it is attached. The morphology of species within Peramelemorphia preclude them from the standard collar attachment of ABDs for terrestrial mammals. Aims. This paper describes a method for the tail-mount attachment of ABDs, and deployment results for Peramelemorphia across arid, semi-arid and temperate Australia to (a) test the performance of attachments and ABDs in the field and (b) discuss the animal welfare considerations for this attachment method. Methods. Tail-mount attachment of ABDs were field-tested on a total of 80 greater bilbies (Macrotis lagotis), and 14 long-nosed bandicoots (Perameles nasuta). Key results. Time to natural detachment (TTND) was between 2 and 52 days, with 65.74% (142 of 216) remaining on until manual removal. For ABDs that were manually removed, attachments were retained for up to 94 days. The method used for tail-mount attachment of ABDs to long-nosed bandicoots resulted in significantly shorter TTND compared with the method used for bilbies, and environmental factors (high temperatures and rainfall) had a negative effect on TTND. Tail-mount attached global positioning system (GPS) sensors collected large quantities of accurate data, with a maximum fix success rate of 83.38%. Damage to GPS (antenna breakage and water ingress) during deployment, however, impacted performance. In environments with frequent rainfall and waterlogged soils, the tape on a small proportion (6.25%) of (n = 192)attachments to bilbies caused tail injury. All injuries were resolvable, with most requiringminimal to no veterinary intervention. Key conclusions. Attachment longevity can be affectedby how the ABD is mounted to the tail, the species and the deployment environment. Theenvironment can also affect which adhesive tapes are suitable for ABD attachment. However, thismethod is highly modifiable, practical for field application and can have long retention timesrelative to other temporary methods. Implications. This ABD tail-mount attachment methodadds another tool to the telemetry tool-kit, with all the benefits of a low-tech, low-cost, passivedrop-off type attachment. This method has demonstrated practicality for Peramelemorphia, withpotential application to other suitable small vertebrates
Pharmacological Modulation of Dopamine Receptor D2-Mediated Transmission Alters the Metabolic Phenotype of Diet Induced Obese and Diet Resistant C57Bl6 Mice
High fat feeding induces a variety of obese and lean phenotypes in inbred rodents. Compared to Diet Resistant (DR) rodents, Diet Induced Obese (DIO) rodents are insulin resistant and have a reduced dopamine receptor D2 (DRD2) mediated tone. We hypothesized that this differing dopaminergic tone contributes to the distinct metabolic profiles of these animals.
C57Bl6 mice were classified as DIO or DR based on their weight gain during 10 weeks of high fat feeding. Subsequently DIO mice were treated with the DRD2 agonist bromocriptine and DR mice with the DRD2 antagonist haloperidol for 2 weeks.
Compared to DR mice, the bodyweight of DIO mice was higher and their insulin sensitivity decreased. Haloperidol treatment reduced the voluntary activity and energy expenditure of DR mice and induced insulin resistance in these mice. Conversely, bromocriptine treatment tended to reduce bodyweight and voluntary activity, and reinforce insulin action in DIO mice.
These results show that DRD2 activation partly redirects high fat diet induced metabolic anomalies in obesity-prone mice. Conversely, blocking DRD2 induces an adverse metabolic profile in mice that are inherently resistant to the deleterious effects of high fat food. This suggests that dopaminergic neurotransmission is involved in the control of metabolic phenotype
The relationship between anti-mullerian hormone in women receiving fertility assessments and age at menopause in subfertile women: evidence from large population studies
<p>Context: Anti-Müllerian hormone (AMH) concentration reflects ovarian aging and is argued to be a useful predictor of age at menopause (AMP). It is hypothesized that AMH falling below a critical threshold corresponds to follicle depletion, which results in menopause. With this threshold, theoretical predictions of AMP can be made. Comparisons of such predictions with observed AMP from population studies support the role for AMH as a forecaster of menopause.</p>
<p>Objective: The objective of the study was to investigate whether previous relationships between AMH and AMP are valid using a much larger data set.</p>
<p>Setting: AMH was measured in 27 563 women attending fertility clinics.</p>
<p>Study Design: From these data a model of age-related AMH change was constructed using a robust regression analysis. Data on AMP from subfertile women were obtained from the population-based Prospect-European Prospective Investigation into Cancer and Nutrition (Prospect-EPIC) cohort (n = 2249). By constructing a probability distribution of age at which AMH falls below a critical threshold and fitting this to Prospect-EPIC menopausal age data using maximum likelihood, such a threshold was estimated.</p>
<p>Main Outcome: The main outcome was conformity between observed and predicted AMP.</p>
<p>Results: To get a distribution of AMH-predicted AMP that fit the Prospect-EPIC data, we found the critical AMH threshold should vary among women in such a way that women with low age-specific AMH would have lower thresholds, whereas women with high age-specific AMH would have higher thresholds (mean 0.075 ng/mL; interquartile range 0.038–0.15 ng/mL). Such a varying AMH threshold for menopause is a novel and biologically plausible finding. AMH became undetectable (<0.2 ng/mL) approximately 5 years before the occurrence of menopause, in line with a previous report.</p>
<p>Conclusions: The conformity of the observed and predicted distributions of AMP supports the hypothesis that declining population averages of AMH are associated with menopause, making AMH an excellent candidate biomarker for AMP prediction. Further research will help establish the accuracy of AMH levels to predict AMP within individuals.</p>
The value of anti-Müllerian hormone measurement in the long GnRH agonist protocol: association with ovarian response and gonadotrophin-dose adjustments
The baby's first bites RCT: evaluating a vegetable-exposure and a sensitive-feeding intervention in terms of child health outcomes and maternal feeding behavior during toddlerhood
Education and Child Studie
A Validated Model of Serum Anti-Müllerian Hormone from Conception to Menopause
Background Anti-Müllerian hormone (AMH) is a product of growing ovarian follicles. The concentration of AMH in blood may also reflect the non-growing follicle (NGF) population, i.e. the ovarian reserve, and be of value in predicting reproductive lifespan. A full description of AMH production up to the menopause has not been previously reported. Methodology/Principal Findings By searching the published literature for AMH concentrations in healthy pre-menopausal females, and using our own data (combined ) we have generated and robustly validated the first model of AMH concentration from conception to menopause. This model shows that 34% of the variation in AMH is due to age alone. We have shown that AMH peaks at age 24.5 years, followed by a decline to the menopause. We have also shown that there is a neonatal peak and a potential pre-pubertal peak. Our model allows us to generate normative data at all ages. Conclusions/Significance These data highlight key inflection points in ovarian follicle dynamics. This first validated model of circulating AMH in healthy females describes a transition period in early adulthood, after which AMH reflects the progressive loss of the NGF pool. The existence of a neonatal increase in gonadal activity is confirmed for females. An improved understanding of the relationship between circulating AMH and age will lead to more accurate assessment of ovarian reserve for the individual woman.Publisher PDFPeer reviewe
Impact of female age and male infertility on ovarian reserve markers to predict outcome of assisted reproduction technology cycles
<p>Abstract</p> <p>Background</p> <p>This study was designed to assess the capability of ovarian reserve markers, including baseline FSH levels, baseline anti-Müllerian hormone (AMH) levels, and antral follicle count (AFC), as predictors of live births during IVF cycles, especially for infertile couples with advanced maternal age and/or male factors.</p> <p>Methods</p> <p>A prospective cohort of 336 first IVF/ICSI cycles undergoing a long protocol with GnRH agonist was investigated. Patients with endocrine disorders or unilateral ovaries were excluded.</p> <p>Results</p> <p>Among the ovarian reserve tests, AMH and age had a greater area under the receiving operating characteristic curve than FSH in predicting live births. Furthermore, AMH and age were the sole predictive factors of live births for women greater than or equal to 35 years of age; while AMH was the major determinant of live births for infertile couples with absence of male factors by multivariate logistic regression analysis. However, all the studied ovarain reserve tests were not preditive of live births for women < 35 years of age or infertile couples with male factors.</p> <p>Conclusion</p> <p>The serum AMH levels were prognostic for pregnancy outcome for infertile couples with advanced female age or absence of male factors. The predictive capability of ovarian reserve tests is clearly influenced by the etiology of infertility.</p
Extra- and intra-ovarian factors in polycystic ovary syndrome: impact on oocyte maturation and embryo developmental competence
background: Polycystic ovary syndrome (PCOS) is a common metabolic dysfunction and heterogeneous endocrine disorder in women of reproductive age. Although patients with PCOS are typically characterized by increased numbers of oocytes retrieved during IVF, they are often of poor quality, leading to lower fertilization, cleavage and implantation rates, and a higher miscarriage rate. methods: For this review, we searched the database MEDLINE (1950 to January 2010) and Google for all full texts and/or abstract articles published in English with content related to oocyte maturation and embryo developmental competence. results: The search showed that alteration of many factors may directly or indirectly impair the competence of maturating oocytes through endocrine and local paracrine/autocrine actions, resulting in a lower pregnancy rate in patients with PCOS. The extra-ovarian factors identified included gonadotrophins, hyperandrogenemia and hyperinsulinemia, although intra-ovarian factors included members of the epidermal, fibroblast, insulin-like and neurotrophin families of growth factors, as well as the cytokines. conclusions: Any abnormality in the extra- and/or intra-ovarian factors may negatively affect the granulosa cell-oocyte interaction, oocyte maturation and potential embryonic developmental competence, contributing to unsuccessful outcomes for patients with PCOS who are undergoing assisted reproduction.Obstetrics & GynecologyReproductive BiologySCI(E)PubMed49REVIEW117-331
Anti-Mullerian hormone as a predictor of ovarian reserve in ART protocols: the hidden role of thyroid autoimmunity
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