9 research outputs found

    Some seasonal changes in Antechinus flavipes (Marsupialia : Dayuridae)

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    Age Determination in the Kangaroo Island Wallaby, Macropus eugenii (Desmarest)

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    Thigh-length compression stockings and DVT after stroke

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    Controversy exists as to whether neoadjuvant chemotherapy improves survival in patients with invasive bladder cancer, despite randomised controlled trials of more than 3000 patients. We undertook a systematic review and meta-analysis to assess the effect of such treatment on survival in patients with this disease

    Heterogeneity of alpha-cardiac myosin heavy chains in a small marsupial, Antechinus flavipes, and the effect of hypothyroidism on its ventricular myosins

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    The effect of drug-induced hypothyroidism on ventricular myosin gene expression was explored in a small marsupial, Antechinus flavipes. Pyrophosphate gel electrophoresis, SDS-PAGE and western blotting were used to analyse changes in native myosin isoforms and myosin heavy chains (MyHCs) in response to hypothyroidism. In some animals, five instead of the normal three native myosin components were found: V1a, V1b, V1c, V2 and V3, in order of decreasing mobility. In western blots, V1a, V1b, and V1c reacted with anti-a-MyHC antibody, but not with anti-B-MyHC, whereas V2 and V3 reacted with anti-B-MyHC antibody. SDS-PAGE of the unusual ventricular myosins revealed three MyHC isoforms, two of which bound anti-a-MyHC antibody while the third bound anti-B-MyHC antibody. We conclude that V1a, V1b, V1c are triplets arising from the dimerization of two distinct a-MyHC isoforms. Hypothyroidism, veriWed by metabolic studies, decreased a-MyHC content significantly (t-test, P < 0.001) from 91.6 5.9% (SEM, n = 4) in control animals to 67.2 5.7% (SEM, n = 4) in hypothyroid animals, with a concomitant increase in B-MyHC content. We conclude that in adult marsupials, ventricular myosins are also responsive to changes in the thyroid state as found in eutherians, and suggest that evolution of the molecular mechanisms underlying this thyroid responsiveness predate the divergence of marsupials and eutherians

    Reproduction in male swamp wallabies (Wallabia bicolor): puberty and the effects of season

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    This study describes pubertal changes in testes and epididymides and seasonal changes in the adult male reproductive organs and plasma androgen concentrations of the swamp wallaby (Wallabia bicolor). Pre-pubescent males had testes with solid seminiferous cords and spermatogenesis only to the stage of gonocytes. Their epididymides had empty lumina along their entire length. The testes of three males undergoing puberty had some lumen formation and mitotic activity. Their epididymides were similar in appearance to those of adult males but were entirely devoid of any cells within the lumen of the duct. Three other pubescent males showed full lumen formation in the testes and spermatogenesis up to the elongating spermatid stage. Their epididymides were similar in appearance to those of adult males but with no spermatozoa in the duct. However, cells of testicular origin were found in the lumen of the duct in all regions suggesting that testicular fluids and immature germ cells shed into the rete testes flow through the seminiferous tubules into the epididymis before the release of mature testicular spermatozoa. The weights of testes and epididymides of adult males showed no change throughout the year but prostate weight and plasma androgen concentrations varied significantly with season, with maximums in spring and summer and minimums in winter. The volume fraction of Leydig cells and seminiferous tubules was significantly lower in winter than in summer; but, despite this, maturing spermatozoa were found in the testes throughout the year. Females in the area conceived year-round, suggesting that seasonal changes in the male reproductive tract did not prevent at least some males from breeding throughout the year

    The evolution of sociality in small, carnivorous marsupials: The lek hypothesis revisited

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    One of the few mammal species reported to have a mating system of lek promiscuity is the tree-hollow nesting marsupial, the agile antechinus, Antechinus agilis. Past conclusions about its mating system have been based on seasonal changes in social group size, sex-specific nest switching and space use. Thermoregulation has also been suggested as an explanation for variation in social behaviour in this species and its relatives. We tested predictions of the lekking and thermoregulation hypotheses to explain sociality in cavity nesting antechinuses using published data, and new data on brown and subtropical antechinuses. We found that across four species, social group size is negatively correlated with daily minimum temperature, but not with timing of breeding. Females have a matrilineal fission-fusion social system, which continues during the brief mating season, and males range increasingly further throughout their lives, contacting as many females as possible in nests. Males show no indication of fission-fusion sociality. All evidence in species other than A. agilis, and some data on A. agilis, indicate a mating system of scramble polygyny, and not lek promiscuity. We conclude that across species, thermoregulation is the main reason for seasonal variation in nesting group size in both sexes

    Azithromycin in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

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    Background Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatory actions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19. Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospital with COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients were randomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once per day by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatment groups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment and were twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants and local study staff were not masked to the allocated treatment, but all others involved in the trial were masked to the outcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treat population. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936. Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) were eligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was 65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomly allocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall, 561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days (rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median 10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days (rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, no significant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilation or death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24). Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or other prespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restricted to patients in whom there is a clear antimicrobial indication. Funding UK Research and Innovation (Medical Research Council) and National Institute of Health Research
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