A randomized cross-over trial assessing salivary and urinary cortisol concentrations after alfaxalone and propofol administration in healthy cats.

The aim of this study was to assess the effects of commonly used anaesthetics alfaxalone and propofol on salivary and urinary cortisol in healthy cats. Fifteen male castrated research-purposed cats received randomly intravenous continuous rate infusions of 8 mg/kg/h of alfaxalone, 12 mg/kg/h of propofol and 2 ml/kg/h of Lactated Ringer's solution for 30 min, with intervals of 6 days between treatments. Saliva samples were collected for 24 h before each infusion and for 24 h from the start of each infusion. Urine was collected as single pooled samples over each 24 h period. Mean integrated saliva cortisol responses in cats treated with alfaxalone were greater than responses of cats treated with propofol (P = 0.034) and controls (P = 0.017). Integrated responses in cats treated with propofol did not differ from controls. The mean urinary cortisol/creatinine ratio (UCCR) was higher on the day of treatment than the day before treatment in cats treated with alfaxalone (P < 0.0001) and in cats treated with propofol (P = 0.0168) and did not differ between days in cats treated with lactated Ringer's solution. The mean UCCR was higher in cats treated with alfaxalone than in cats treated with lactated Ringer's solution (P = 0.0020) on the day of treatment. Mean total urinary cortisol over 24 h was greater in cats treated with alfaxalone than controls (P = 0.0267). In conclusion, alfaxalone increased short-term salivary and urinary cortisol concentrations in healthy cats as compared to propofol and a control group of non-anesthetised cats.

Corticosterone stress hormone responses in oil rehabilitated and non-rehabilitated little penguins.

Whether oiled wildlife should be rehabilitated during an oil spill is internationally debated. Research on little penguins (LP, Eudyptula minor) rehabilitated and released back into a cleaned environment after the New Zealand C/V Rena grounding oil spill in 2011 found the rehabilitation process was effective at treating and reversing the negative effects of oil-contamination on penguin post-release survival, productivity and diving behaviour. Here we investigated the acute corticosterone stress response of LPs to determine if responses of rehabilitated birds differed from those of "control" birds. Corticosterone responses of LPs two years after an oil spill did not differ between rehabilitated and non-rehabilitated penguins. These results show that the rehabilitation process for LP did not affect their long-term physiological responses to humans. This indicates that wildlife can be rehabilitated and returned to the wild with similar human tolerance levels to non-rehabilitated birds and an absence of habituation.

Fecal corticosterone metabolites and plasma corticosterone in Japanese quail selected for low or high plasma corticosterone responses to brief restraint.

Fecal corticosterone metabolites and plasma corticosterone in Japanese quail selected for low- or high-plasma corticosterone responses to brief mechanical restraint (low- and high-stress lines), and in a line of unselected quail, were measured in this study. No line differences were observed in baseline plasma corticosterone concentrations, but fecal corticosterone metabolite concentrations and daily fecal corticosterone metabolite production were 20% higher in quail of the high-stress line than in unselected or low-stress quail for males and females living together in group cages (P < 0.05). No differences were observed between lines in corticosterone metabolite concentrations and production for male birds in individual cages. Baseline plasma corticosterone concentrations, fecal corticosterone metabolite concentrations, and production appeared to be higher for males and females in group cages compared with males in individual cages. This difference might have been because of greater corticosterone secretion by male quail living in mixed sex groups than living individually. Correlations between baseline plasma corticosterone concentrations and fecal corticosterone metabolite concentrations in low-stress and high-stress quail, and for all birds combined, were r = 0.521 (P = 0.038), r = 0.604 (P = 0.013), and r = 0.431 (P = 0.002), respectively. The low- and high-stress lines that have been selected for low- and high-corticosterone responses differ in other characteristics, including growth and reproductive performance, and the current results are consistent with the assumption that these other differences are a consequence of greater daily corticosterone secretion in quail of the high-stress line.

Plasma corticosterone responses to handling in Japanese quail selected for low or high plasma corticosterone responses to brief restraint.

1. Plasma corticosterone responses to handling in Japanese quail selected for low or high corticosterone responses to brief mechanical restraint (low and high stress lines) were measured in this study. 2. Initial corticosterone concentrations did not differ between the two lines. Corticosterone concentrations increased 15 min after handling began in quail handled for 5 or 15 min, with greater increases in quail from the high stress than the low stress line. Integrated corticosterone responses were higher in high stress than low stress quail, although the difference between the lines was not significant in quail handled for 5 min. 3. Patterns of plasma corticosterone after 15 min differed between quail handled for 5 or 15 min. Corticosterone increased further or did not change from 15 to 30 min then decreased from 30 to 60 min in quail handled for 5 min, whereas corticosterone decreased from 15 to 30 min then did not change in quail handled for 15 min. Corticosterone concentrations at 60 min remained elevated above initial concentrations, and were similar in quail handled for 5 or 15 min. Corticosterone concentrations at 15 min were more than twice as high in quail handled for 15 min compared with quail handled for 5 min. 4. Although the lines of quail have been selected on the magnitude of corticosterone responses, there was still marked variation in responses between birds within each line. Some quail in the high stress line showed little or no corticosterone response to handling, whilst large responses were seen in some birds of the low stress line. The lines of quail differ in characteristics other than corticosterone responses, including fear behaviour and reproductive development, so the lines provide valuable opportunities to investigate the potential significance of differences between individual birds in their corticosterone responses.

Non-precocial grey-faced petrel chicks (Pterodroma macroptera gouldi) show no age-related variation in corticosterone responses to capture and handling.

Development patterns in birds range from precocial species, which hatch chicks largely capable of independent existence, to altricial species, chicks of which are highly dependent on their parents for extended periods. Previous work indicates precocial chicks have a robust corticosterone response from hatching whereas non-precocial and altricial chicks have a small response that increases through development. Grey-faced petrels are characteristic of most burrowing procellariiform seabirds with non-precocial chicks that are unable to locomote and are dependent on adults for food, although chicks have well developed downy plumage and can thermoregulate at or soon after hatching. Initial plasma corticosterone concentrations and corticosterone responses to handling were measured during development in semi-precocial grey-faced petrel (Pterodroma macroptera gouldi) chicks to determine whether they showed a precocial or altricial corticosterone response pattern. Chicks were sampled at six intervals through development from shortly after hatching until close to fledging. Mean corticosterone responses to handling after 30 min were high (115.9+/-10.7 ng/ml) from 2 to 4d after hatching and remained high throughout development (70-110 ng/ml). Contrary to expectations for non-precocial chicks, this pattern of corticosterone responses to handling indicates that grey-faced petrel chicks are able to perceive and respond to potential stressors from hatching, a response previously only demonstrated for precocial birds.

Effects of corticosterone treatment on growth, development, and the corticosterone response to handling in young Japanese quail (Coturnix coturnix japonica).

Corticosterone, a glucocorticoid secreted during stress responses, has a range of actions that help birds respond to stressors. Although effects of corticosterone treatment have been described in several avian species, the impacts of defined increases in plasma corticosterone on early development and on corticosterone stress responses are little known. These issues were addressed by providing quail with different doses of corticosterone in drinking water from days 8 to 38 post-hatch. The corticosterone dose consumed by each bird during treatment days 15-30 was calculated by measuring water intake. The corticosterone dose was inversely, but weakly, correlated with weights of the bursa, thymus, spleen, liver, testes, oviduct, muscle, and body, and positively correlated with peritoneal fat deposition. When birds were divided into groups based on their corticosterone intake, weights of the spleen, thymus, bursa, muscle, testes, and oviduct were significantly reduced in birds receiving the highest doses; with the exception of muscle, similar reductions were also observed in birds receiving medium doses, and thymic growth was inhibited in birds receiving low doses. The acute corticosterone stress response was measured by handling birds for 15 min. Plasma corticosterone was transiently increased at 15 min in control birds in response to the handling stressor. Some birds consuming low doses of corticosterone had corticosterone responses similar to control birds. Initial corticosterone concentrations were elevated in birds consuming higher doses of corticosterone. Plasma corticosterone in these birds decreased from 0 to 15 min, then increased from 15 to 30 min. The initial decrease could be due to corticosterone clearance, whilst the increase could indicate that the birds had a greater response than control birds to isolation as a stressor. Corticosterone treatment may have reduced the strength of corticosterone negative feedback within the hypothalamo-pituitary-adrenal axis. The results indicate that individuals and organs differ in their sensitivity to corticosterone. Moreover, elevated plasma corticosterone may disrupt the acute corticosterone stress response, and may thus reduce the ability of birds to cope with stressors.

Corticosterone in relation to body mass in Adelie penguins (Pygoscelis adeliae) affected by unusual sea ice conditions at Ross Island, Antarctica.

Penguins naturally fast each year during breeding and again whilst moulting, and may lose more than 40% of body mass during a fast. Fasting in emperor (Aptenodytes forsteri) and king (Aptenodytes patagonicus) penguins has been divided into three phases, with phase III characterised by an increased rate of body mass loss, increased plasma corticosterone concentrations, and a change in behaviour leading to abandonment of the breeding attempt and return to sea to feed. Initial corticosterone concentrations and corticosterone responses to a handling stressor were measured in the current study to determine if they increase during phase III of fasting in Adelie penguins (Pygoscelis adeliae). The study was conducted in 2001 at the northern Cape Bird colony on Ross Island, Antarctica. Penguin breeding on Ross Island was disrupted in the 2001-2002 summer by a large iceberg (B15A) which stopped the normal movement of sea ice in the Ross Sea. Penguins departing from the Cape Bird colony were lighter than returning or incubating birds (3.39+/-0.10cf. 4.16+/-0.06 and 4.07+/-0.08kg). It is likely that the departing birds were males that had been lighter than normal when they arrived at the colony. Initial plasma corticosterone concentrations were higher in departing than returning or incubating penguins (6.89+/-1.69cf. 2.36+/-0.42 and 1.08+/-0.19ng/ml). Corticosterone responses to handling were also greater in departing penguins. Initial plasma corticosterone, concentrations at 30min and total and corrected integrated corticosterone responses were inversely related to body mass in departing penguins, whereas there were no relationships in arriving penguins. beta-hydroxybutyrate and uric acid concentrations were consistent with departing birds having entered phase III of fasting. The results indicate that corticosterone and corticosterone responses are elevated in phase III of fasting in the Adelie penguin.

Corticosterone responses of grey-faced petrels (Pterodroma macroptera gouldi) are higher during incubation than during other breeding stages.

We report the results of the first field study examining seasonal changes in corticosterone responses of typically long-lived birds of the order Procellariiformes. In particular, we examined whether grey-faced petrels Pterodroma macroptera gouldi showed changes in circulating baseline corticosterone concentrations and corticosterone responses to a standardized handling protocol across the breeding season. Such changes have been associated with changes in body condition and variations in energy demands on adult birds through the breeding season. During early incubation, males were in significantly better condition than females that had just completed laying, whereas during late incubation, males were in significantly poorer condition than females. In spite of these differences, there was no significant difference in baseline corticosterone concentrations between sexes or among birds at different reproductive stages. However, we detected significant differences in corticosterone responses associated with a standardized handling protocol at different stages through the breeding season. Responses were significantly greater during incubation compared with the prelay period and late chick rearing. Body condition was weakly and negatively correlated with maximum and total integrated corticosterone level, indicating that some of the individual variability in stress corticosterone responses could be explained by variation in body condition. However, the largest stress response occurred during late incubation and was independent of sex, although males were in relatively poor condition and females in relatively good condition. This period coincided with the breeding stage in which energy constraints on individual adults were higher than at other periods of the reproductive cycle and birds may be physiologically primed for extended fasts.

Competition for male reproductive investment elevates testosterone levels in female dunnocks, Prunella modularis.

In many songbirds, females occasionally sing in contexts of high female-female competition. Testosterone may be involved in the activation of song, because testosterone implants elicit female song in many species with rare female song. A possible mechanism for the hormonal control of female song is provided by the challenge hypothesis, which predicts a rise in testosterone in response to aggressive interactions during socially unstable situations. We tested this by comparing faecal testosterone levels in polygynandrous and monogamous female dunnocks. In groups with two to three females (polygynandry and polygyny) males provide less help at each nest than in groups with a single female (monogamy and polyandry). Polygynandrous and polygynous females are aggressive towards one another and attempt to expel rivals. Polygynandrous females had significantly higher testosterone levels than monogamous females. Competition between females that was induced by removal of males caused testosterone levels to rise. Further, female testosterone levels were correlated with the rate of 'tseep' calls, which are produced during aggressive encounters between females. Finally, polygynandrous and polygynous females sang significantly more than monogamous females. To the best of our knowledge, these results provide the first experimental support for the challenge hypothesis in female birds, and suggest that testosterone can regulate facultative female song in songbirds.

Gastrin secretion by ovine antral mucosa in vitro.

The effect on gastrin and somatostatin release in sheep of stimulatory and inhibitory peptides and pharmacological agents was investigated using an in vitro preparation of ovine antral mucosa. Carbachol stimulated gastrin release in a dose-dependent manner but had no effect on somatostatin release. As atropine blocked the effect of carbachol, cholinergic agonists appear to stimulate gastrin secretion directly through muscarinic receptors on the G-cell and not by inhibition of somatostatin secretion. Both vasoactive-intestinal peptide (VIP) and gastric-inhibitory peptide (GIP) increased somatostatin release but did not inhibit basal gastrin secretion, although VIP was effective in reducing the gastrin response to Gastrin-releasing peptide (GRP). Porcine and human GRP were stimulatory to gastrin secretion in high doses but bombesin was without effect. The relative insensitivity to GRP (not of ovine origin) previously reported from intact sheep may be caused either by a high basal release of somatostatin or by the ovine GRP receptor or peptide differing from those of other mammalian species.

Discrepancies between cerebral computed tomography and western blot in the diagnosis of neurocysticercosis. The Cysticercosis Working Group in Peru (Clinical Studies Coordination Board).

Serum samples from sequential patients who underwent cerebral computed axial tomography (CT) scan in a Peruvian radiologic clinic were tested by the highly sensitive and specific enzyme-linked immunoelectrotransfer blot (EITB) test to detect antibodies to Taenia solium. The results of the EITB test were compared with those obtained by CT scan for the diagnosis of neurocysticercosis. Of the 383 patients sampled, 32 (8%) were seropositive. The results of CT and EITB were frequently discrepant. When compared with the EITB assay, the CT scan was 44% sensitive and 95% specific. The sensitivity of CT increased to 63% if less specific images (single calcifications, granulomas, or hydrocephalus) were included. The CT scan for diagnosis of cysticercosis can best be used in conjunction with a reliable serologic test such as the EITB.

MRI in motor delay: important adjunct to classification of cerebral palsy.

Cranial magnetic resonance imaging (MRI) was performed prospectively in 45 children (ages 3-27 months) with clinically documented motor delay to evaluate the ability of MRI to determine etiologic factors, to determine whether myelination correlated with motor delay, and whether the clinical category corresponded with the imaging findings. Of the 22 children diagnosed clinically as having major motor delay (i.e., cerebral palsy), 77% had magnetic resonance imaging abnormalities. In 23%, etiologic associations were established from MRI alone and in 32% a clinically suspected etiology was supported. No children had myelination delay as the sole abnormality. In 23 children with minor motor delay, only 17% had abnormal scans. Clearly, MRI provided useful information in the majority of children with cerebral palsy; therefore, a classification system is proposed in which MRI can be used in conjunction with clinical assessment to specify more precisely the etiologic factors in cerebral palsy.

Imaging of neurodegenerative diseases.

Neuroimaging of degenerative brain disorders has continued to advance, primarily with MR imaging, single-photon emission CT, and positron emission tomography. Information gained from these morphologic and functional imaging studies provides insight into the pathologic and pathophysiologic changes associated with these diseases. Recent papers relating to various neurodegenerative disorders such as Alzheimer's disease, vascular dementias, acquired immunodeficiency syndrome-related dementia, Pick's disease, Huntington's disease, progressive supranuclear palsy, and others are reviewed and discussed.

Identification of some substances secreted by the bovine pineal body and their antigonadotrophic activity in an in vitro system.

To aid elucidation of the chemical composition of the antigonadotrophic substances produced by the epiphysis cerebri, 100 bovine pineal bodies were incubated in Krebs-Ringer buffer and the incubate treated to give an ethyl acetate and an aqueous extract. Using thin layer chromatography on fluorescent silica gel plates, 5 indoles were identified and 6 unknown substances isolated from the pineal incubate and from both extracts. The presence of peptides was detected in the incubate and in the aqueous extract. The antigonadotrophic activity of the incubate and of the two extracts was examined using a continuous flow in vitro system with the production of luteinizing hormone (LH) from bovine adenohypophysial tissue as the final parameter. All three fractions were found to result in a somewhat similar production of LH. To distinguish between the antigonadotrophic activity attributable to the indole and the indole/protein components of the pineal secretion, 90 bovine pineal bodies were homogenized and the homogenate incubated in the continuous flow in vitro system in the presence or absence of trypsin and trypsin-inhibitor. Results were inconclusive regarding the role played by the indole and indole/protein fractions in the antigonadotrophic activity of the pineal body.