Ecosystem collapse in Pleistocene Australia and a human role in megafaunal extinction

Most of Australia's largest mammals became extinct 50,000 to 45,000 years ago, shortly after humans colonized the continent. Without exceptional climate change at that time, a human cause is inferred, but a mechanism remains elusive. A 140,000-year record of dietary delta(13)C documents a permanent reduction in food sources available to the Australian emu, beginning about the time of human colonization; a change replicated at three widely separated sites and in the marsupial wombat. We speculate that human firing of landscapes rapidly converted a drought-adapted mosaic of trees, shrubs, and nutritious grasslands to the modern fire-adapted desert scrub. Animals that could adapt survived; those that could not, became extinct.     

Validation of liquid chromatographic method for assay of chlorthalidone in tablet formulations

A stability-indicating, reverse phase liquid chromatographic (LC) method was developed for assay of chlorthalidone in tablet formulations. The chromatographic system separates the parent compound from its potential hydrolysis product (4'-chloro-3'-sulfamoyl-2-benzophenone carboxylic acid), which can be quantitated at low levels, and another degradation product (2-chloro-5-(1-methoxy-3-oxo-1-isoindolinyl)benzenesulfonamide), which was found during the experimental work. The procedure can also be used for content uniformity determinations. The general utility of the method was demonstrated by the assay of several product brands. The validated procedure was shown to be accurate, precise, reproducible, and specific.     

The Functional Role of Oxytocin in the Induction of Oocyte Meiotic Resumption in Cattle

The aim of the present study was to examine the role of oxytocin (OT) in the progesterone (P4) and prostaglandins (PGs) pathway to induce oocyte meiotic resumption. Cumulus–oocyte complexes were co‐cultured with follicular hemisections for 15 h to determine the effects of different doses of OT or atosiban (ATO; oxytocin receptor antagonist) on oocyte meiotic resumption. In another experiment, we examined the effect of the interaction between P4, OT and PGs on the regulatory cascade of the oocyte meiotic resumption. Oxytocin at 1 μm was effective in inducing meiotic resumption in oocytes co‐cultured with follicular cells (84.0%), not differing from the positive control group (74.4%). Atosiban inhibited in a dose‐dependent manner the positive effect of OT on the meiotic resumption (27.6% metaphase I with 10 μm of ATO, which did not differ from the 25.5% of the negative control group). Furthermore, a third experiment showed that P4 was able to induce oocyte meiotic resumption, which was inhibited by ATO. However, the OT positive effect was not blocked by mifepristone (P4 antagonist), but was inhibited by indomethacin (a non‐selective PTGS2 inhibitor). Collectively, these data suggest a sequential role of P4, OT and PGs in the induction of oocyte meiotic resumption.     

动物疫苗及其合理使用（一）

疫苗接种是预防动物传染病发生的重要举措。依据免疫学理论,疫苗作为抗原,通过激发动物机体免疫系统,产生特异的体液免疫和细胞免疫,从而获得针对某种疾病的特异性免疫。疫苗一般分为细菌疫苗、病毒疫苗和类毒素疫苗等。用于防病治病的各种疫苗、菌苗又是特殊的生物药品,与普通化学药品具有完全不同的成分、功能和特性,疫苗中含有多种蛋白质（除细菌或病毒外,有的还含有保护剂、鸡胚尿囊液或细胞培养液）,它们均适合许多病原体的生长,有些制品还是活的微生物,一旦污染后果不堪设想。疫苗在保存、运输和使用时有其特别要求。如果方法不当,不但会使活性物质失活,起不到免疫防病作用;而且还可能适得其反,引发动物新的疾病,造成重大损失。     

Disposition of suprofen enantiomers in the cat.

Suprofen (SPF) is a non-steroidal anti-inflammatory drug (NSAID), which belongs to the 2-arylpropionic acids subclass. As a result of their chiral characteristics, these compounds have shown a marked enantioselective behaviour with a high degree of interspecies variation. They are mainly eliminated by glucuronidation. Plasma, biliary and urine disposition of SPF was investigated in the cat after intravenous administration of the racemate (dose 2 mg/kg). Both enantiomers exhibited similar disposition profiles in plasma with no evidence of chiral inversion. During bile sampling time, recovered acylglucuronides of R (-) and S (+) SPF were less than 1% of the total dose administered. Only free SPF was recovered in the urine, representing 0.12% of the administered racemic SPF dose. The results indicate that neither chiral inversion nor glucuronidation predominate in SPF disposition in cats. Copyright Harcourt Publishers Ltd.     

Identification of Chlamydia gallinacea in a parrot and in free‐range chickens in Australia

Chlamydia gallinacea is a recently described bacterial species in a genus known to infect and cause disease in animals and humans. Our report describes the identification of C. gallinacea infection in free‐range laying chickens (Gallus gallus) in Australia, and the identification of C. gallinacea infection in a parrot, a wild Australian galah (Eolophus roseicapillus). There is currently little knowledge of the effects of C. gallinacea infection on avian hosts, but it has been linked to respiratory disease in humans and could potentially cause similar disease in other species. Our report highlights the need for further study and surveillance of Chlamydia species in both wild and domestic hosts in Australia.