Observer variability and sensitivity of radiographic diagnosis of canine medial coronoid disease.

OBJECTIVE: Medial coronoid disease (MCD) is a very common form of elbow joint disease and it's radiographic diagnosis can be challenging since it is frequently based on the detection of rather subtle primary or secondary changes than on a large primary lesion. We hypothesized that accuracy of radiographic diagnosis of MCD is highly dependent on training and experience level. METHODS: Radiographs of 102 canine elbows were evaluated for MCD by four observers with different levels of training and experience. All elbows underwent CT scans and arthroscopy. Sensitivity and specificity of radiographic and CT interpretation was determined using arthroscopy as a gold standard. Interobserver and intraobserver agreement (reliability and repeatability) were assessed by using Cohen's Kappa (κ) statistic. RESULTS: The sensitivity (92.4-96.7%) of the two experienced observers was almost comparable to that of CT (100%) and significantly higher than that of the two less experienced observers (77.2-80.4%). Reliability of the radiographic diagnosis of MCD was better between observers with higher experience level (κ= 0.74) than between observers of lower or different experience levels (κ=0.07-0.42). Repeatability was better in experienced (κ= 0.73-0.88) than in less experienced observers (κ= 0.31-0.42). CONCLUSION: Our results confirm that training and experience play important roles in reaching high sensitivity, reliability and repeatability for the radiographic diagnosis of MCD. CLINICAL RELEVANCE: Although radiography is inferior to CT in imaging of the medial coronoid process itself, sensitivity of radiographic diagnosis MCD can be significantly improved with observer experience almost reaching that of CT. Therefore, it is advised that radiographic screening for MCD should be performed by specialists experienced in the radiographic evaluation of elbow joint disease.

Immune challenge induces differential corticosterone and interleukin-6 responsiveness in rats bred for extremes in anxiety-related behavior.

Disturbances in mood such as anxiety and depression are often associated with altered hypothalamo-pituitary-adrenal (HPA) axis reactivity, but also with changes in cytokine production, such as interleukin-6 (IL-6), an essential immune factor produced by macrophages and lymphocytes during inflammatory processes. The reciprocal relationship between the HPA axis and the immune system is now well established. In order to understand better the endocrine reactivity of anxious individuals faced with an immune challenge, a model of innate anxiety-related behavior, HAB and LAB rats (HABs, high and LABs, low anxiety-related behavior) was used in this study. We sought to determine whether injection of lipopolysaccharide (LPS) induced a differential HPA axis reactivity and plasma IL-6 release in HABs and LABs. After LPS injection, the plasma adrenal corticotrophic hormone increase did not differ between HABs and LABs, whereas a larger increase in plasma corticosterone levels occurred in HABs than in LABs at 2 h after injection. Moreover, basal IL-6 levels were lower in HABs than in LABs, leading to a higher IL-6 2 h/basal ratio in HABs. In conclusion, we propose for the first time a link between the endocrine and immune systems of HABs and LABs and suggest that IL-6 could be a neuroendocrine correlate of trait anxiety in HABs.

Differential effects of periodic maternal separation on adult stress coping in a rat model of extremes in trait anxiety.

We studied interactions of genetic and environmental factors shaping adult emotionality and stress coping, and tested the hypothesis that repeated periodic maternal deprivation (PMD) exerts differential effects on adult behavioral and neuroendocrine stress responsiveness in dependence on the genetic predisposition to either hyper- or hypo-anxiety. Exposure of male Wistar rats bidirectionally bred for either high (HAB) or low (LAB) anxiety-related behavior to PMD between postnatal days 2 and 15 resulted in a behavioral approximation of the selected lines. This was reflected by test-dependent signs of reduced anxiety-related behavior in adult HAB rats and of enhanced levels of anxiety in LAB rats compared with their corresponding unstressed controls. In addition to behavioral parameters, differential effects of PMD were also seen with respect to the responsiveness of the hypothalamo-pituitary-adrenocortical axis to acute stressor exposure (novel environment) in adulthood. The corticotrophin (ACTH) and corticosterone hyper-responses seen in control rats of the HAB line compared with those of the LAB line became attenuated in PMD-HAB rats, whereas PMD did not significantly alter neuroendocrine responses in LAB rats. Thus, as a result of PMD, both ACTH and corticosterone responses became indistinguishable between HAB and LAB rats. Although HAB dams spent more time on the nest with the litter compared with LAB dams during the first 5 days postpartum, licking and grooming behavior did not differ between the lines prior to separation, and was found to be increased to the same extent in both HAB and LAB dams during the first hour immediately after reunion with the pups. In contrast to early life stress, exposure of adult HAB and LAB rats to a 10-day unpredictable stress schedule failed to alter their emotional measures. The mitigating effect of PMD on both behavioral and neuroendocrine parameters in rats representing extremes in trait anxiety might reflect an evolutionary benefit as the genetic variability among individuals of a species is sustained while allowing adequate responses to potentially dangerous stimuli in adulthood dependent on early life conditions.

Nonresponsiveness of the rat hypothalamo-pituitary-adrenocortical axis to parturition-related events: inhibitory action of endogenous opioids.

During the last 2 days of pregnancy in rats, basal corticosterone secretion is enhanced, although the response of the hypothalamo-pituitary-adrenocortical (HPA) axis to emotional and physical stressors is blunted, independent of the action of endogenous opioids. In this study, alterations in the reactivity of the HPA axis, which may accompany parturition-related stimuli, and the involvement of endogenous opioids were examined in chronically catheterized rats. In vehicle-treated controls (n = 9), ACTH and corticosterone secretion decreased in preparation for birth (P < 0.01) and further declined immediately after delivery of the second pup (P < 0.01), remaining low for 150 min. In contrast, in animals injected with the opiate antagonist naloxone (5 mg ml(-1) kg(-1), i.v., n = 6) after delivery of the second pup, ACTH and corticosterone release were enhanced within 20 min (ACTH, 5.0-fold; corticosterone, 2.3-fold; P < 0.01 vs. controls) and returned to control levels after 90 min. In confirmation of previous reports, oxytocin secretion into blood was elevated in control rats after the onset of parturition (P < 0.01) and was further enhanced in the naloxone group (1.4-fold, P < 0.01 vs. control). Plasma lactate concentration was increased, 30 min after the onset of delivery (1.9-fold, P < 0.01), independent of the treatment. The data indicate that parturition-related events do not trigger HPA axis hormone release because of an effective inhibition by endogenous opioids. This nonresponsiveness of the HPA axis is likely to protect the pups' well-being during birth.

Neuroendocrine and behavioral effects of repetitive transcranial magnetic stimulation in a psychopathological animal model are suggestive of antidepressant-like effects.

The neuroendocrine and behavioral effects of repetitive transcranial magnetic stimulation (rTMS) were investigated in two rat lines selectively bred for high and low anxiety-related behavior. The stimulation parameters were adjusted according to the results of accurate computer-assisted and magnetic resonance imaging-based reconstructions of the current density distributions induced by rTMS in the rat and human brain, ensuring comparable stimulation patterns in both cases. Adult male rats were treated in two 3-day series under halothane anesthesia. In the forced swim test, rTMS-treatment induced a more active coping strategy in the high anxiety-related behavior rats only (time spent struggling; 332% vs. controls), allowing these animals to reach the performance of low anxiety-related behavior rats. In contrast, rTMS-treated low anxiety-related behavior rats did not change their swimming behavior. The development of active coping strategies in high anxiety-related behavior rats was accompanied by a significantly attenuated stress-induced elevation of plasma corticotropin and corticosterone concentrations. In summary, the behavioral and neuroendocrine effects of rTMS of frontal brain regions in high anxiety-related behavior rats are comparable to the effects of antidepressant drug treatment. Interestingly, in the psychopathological animal model repetitive transcranial magnetic stimulation induced changes in stress coping abilities in the high-anxiety line only.

Endogenous opioid regulation of stress-induced oxytocin release within the hypothalamic paraventricular nucleus is reversed in late pregnancy: a microdialysis study.

Oxytocin secretion into blood in response to swim stress is differentially regulated by endogenous opioids in virgin and pregnant rats. Here, the influence of endogenous opioids on oxytocin release within the hypothalamic paraventricular and supraoptic nuclei was investigated using microdialysis in virgin and pregnant (day 19-21) rats. Rats fitted with a U-shaped microdialysis probe 3 days before testing were injected with naloxone (5 mg/kg body weight, s.c.) or vehicle (sterile saline) and, 3 min later, were forced to swim (10 min at 19 degrees C). Within the paraventricular nucleus, basal and stimulated oxytocin release did not significantly differ between vehicle-treated virgin and pregnant rats. After naloxone, local oxytocin release in response to swimming was lowered in virgin rats (P<0.01), whereas it was further increased in pregnant rats (P<0.01). Within the supraoptic nucleus, basal oxytocin release was significantly lower in pregnant compared to virgin rats (P<0.01). Forced swimming induced a similar rise in intranuclear oxytocin release in both vehicle-treated virgin and pregnant rats, but peak levels were still higher in the virgin controls. In contrast to the paraventricular nucleus, naloxone did not alter swim-induced oxytocin release within the supraoptic nucleus either in virgin or pregnant rats. Vasopressin release in the paraventricular nucleus was also increased by forced swimming but there was no effect of pregnancy or naloxone on it. In summary, in pregnancy, basal and stress-induced oxytocin release within the paraventricular nucleus was not changed, whereas it was blunted within the supraoptic nucleus. Further, within the paraventricular nucleus the excitatory effect of endogenous opioids on local oxytocin release seen in virgins was switched into an inhibitory action in pregnancy. In contrast, endogenous opioids were evidently not involved in the regulation of swim-induced oxytocin release within the supraoptic nucleus either in virgin or pregnant rats. Thus, pregnancy-related neuroendocrine plasticity also includes site-specific functional alterations in opioid receptor-mediated actions in the hypothalamus.

Brain oxytocin: differential inhibition of neuroendocrine stress responses and anxiety-related behaviour in virgin, pregnant and lactating rats.

The involvement of brain oxytocin in the attenuated responsiveness of the hypothalamo-pituitary-adrenal axis and the oxytocin systems to external stressors found in pregnant and lactating rats has been studied, including both neuroendocrine and behavioural aspects. Intracerebroventricular infusion of an oxytocin receptor antagonist (0.75 microg/5 microl), but not of vehicle, elevated basal corticotropin and corticosterone secretion into blood of virgin female, but not of late pregnant or lactating rats. Oxytocin antagonist treatment further elevated the stress-induced (exposure to the elevated plus-maze or forced swimming) secretion of both corticotropin and corticosterone, but only in virgin and not in pregnant or lactating rats. Thus, corticotropin and corticosterone plasma concentrations remained attenuated in antagonist-treated pregnant and lactating animals. In contrast, infusion of the oxytocin antagonist significantly elevated the stress-induced secretion of oxytocin into blood in pregnant and lactating, but not in virgin, animals, indicating an autoinhibitory influence of intracerebral oxytocin on neurohypophysial oxytocin secretion induced by non-reproduction-related stimuli. Treatment with oxytocin antagonist 10 min prior to behavioural testing on the elevated plus-maze significantly reduced the anxiety-related behaviour in both pregnant and lactating rats, without exerting similar effects in virgin female rats. The results demonstrate a tonic inhibitory effect of endogenous oxytocin on corticotropin and, consequently, corticosterone secretion in virgin female rats, an effect which is absent in the peripartum period. In contrast, an anxiolytic action of endogenous oxytocin was detectable exclusively in pregnant and lactating rats. Therefore, we conclude that the actions of intracerebral oxytocin include independent effects on the responses of the hypothalamo-pituitary-adrenal axis and oxytocin systems to stressors and the anxiety-related behaviour which are modulated by the reproductive state of the animals.

The role of endogenous opioids in neurohypophysial and hypothalamo-pituitary-adrenal axis hormone secretory responses to stress in pregnant rats.

Endogenous opioid regulation of neurohypophysial and hypothalamo-pituitary-adrenal (HPA) axis hormone secretion in response to forced swimming (90 s in deep water at 19 degrees C) was investigated in virgin and 21-day-pregnant rats. There was no difference in basal plasma oxytocin concentrations between pregnant and virgin rats, but the opioid antagonist, naloxone, increased basal oxytocin secretion in the pregnant rats. Forced swimming increased oxytocin secretion similarly in pregnant and virgin rats, and this response was enhanced by naloxone. In pregnant rats naloxone had a greater effect (by 3.1-fold) than in virgins, showing stronger endogenous opioid restraint of an enhanced oxytocin secretory response to stress in pregnancy. Vasopressin secretion was not increased with forced swimming in virgin or pregnant rats, and naloxone had no effect. ACTH and corticosterone secretion in response to forced swimming was attenuated in pregnant rats compared to virgin rats, measured at 5 min. Naloxone had no effect on basal plasma ACTH or corticosterone concentration, but it reduced ACTH secretion in virgin rats 5 min after forced swimming; in pregnant rats naloxone had no such effect. Naloxone removed the pregnancy-related attenuation in corticosterone secretion measured at 5 min after forced swimming. Fifteen minutes after forced swimming, plasma corticosterone concentrations were not different between groups. In the late-pregnant rats, the increases in plasma ACTH and corticosterone induced by forced swimming were significantly prolonged compared to virgins. The results show that endogenous opioid inhibition emerges in pregnancy to restrict the responses of oxytocin neurones to a stressor. In contrast, the endogenous opioid enhancement of mechanisms regulating HPA axis secretory responses in virgin rats is not evident during pregnancy.

Increased basal activity of the hypothalamo-pituitary-adrenal axis during pregnancy in rats bred for high anxiety-related behaviour.

In order to test the hypothesis that prenatal hormones influence the emotional maturation of the offspring, the hypothalamo-pituitary-adrenal (HPA) axis activity was studied at the end of pregnancy in two rat breeding lines differing consistently in their innate anxiety-related behaviour in the elevated plus-maze. Virgin and pregnant rats were fitted with a chronic jugular vein catheter and tested 5 days later. The high basal level of anxiety-related behaviour (HAB) described in males and females of the HAB breeding line persists in pregnancy as indicated by a significantly reduced number of entries into and time spent on the open arms of the elevated plus-maze between days 18 and 20 of pregnancy compared with pregnant rats of the breeding line with low anxiety-related behaviour (LAB). In general, an increase in anxiety was found in both breeding lines in pregnancy compared with the respective virgin controls. With respect to HPA axis activity, increased basal levels of adrenocorticotropin (ACTH) and corticosterone have been found in pregnant rats of the HAB line compared with pregnant LAB rats. ACTH and corticosterone secretion in response to emotional and complex physical stressors (exposure to the elevated plus-maze and forced swimming, respectively) did not differ between virgin and pregnant rats of either breeding line. However, independent of the inborn emotionality of the animals, a general attenuation in the HPA axis response to stressors and to exogenous CRH could be confirmed in pregnant rats. The basal and stress-induced activity of the hypothalamo-neurohypophysial system secreting oxytocin and vasopressin was also tested, and no differences were found relating to the emotionality or reproductive state of the animals except for a reduced vasopressin secretion in pregnant HAB rats after forced swimming. The elevated basal activity of the HPA axis, including enhanced circulating concentrations of corticosterone in pregnant HAB rats, may influence both the neuroendocrine and emotional development of their offspring. Thus, the passing-on of maternal behavioural characteristics via prenatal, hormonal 'imprinting' has to be considered as a possible contribution to emotional maturation during an individual's development.

Hyper-reactive hypothalamo-pituitary-adrenocortical axis in rats bred for high anxiety-related behaviour.

Psychiatric patients suffering from anxiety disorders or endogenous depression exhibit increased activity in their hypothalamo-pituitary-adrenocortical (HPA) axis. Recently, two Wistar rat lines, bred for high (HAB) and low (LAB) anxiety-related behaviour on the elevated plus-maze, were described as a unique psychopathological animal model (1). The present study focused on the HPA axis reactivity of HAB and LAB animals to an emotional stressor. Thus, adult male HAB and LAB animals, fitted with jugular vein catheters 5 days prior to the experiment, were exposed to an open arm of the elevated plus-maze for 5 min. Whereas basal levels of ACTH and corticosterone were similar in both lines, HAB rats showed higher plasma concentrations at 5 and 15 min following stressor exposure (both hormones and both time points: P<0.01 vs LAB). Furthermore, increased basal (P<0.05 vs LAB) and stimulated (P<0.01 vs LAB) prolactin concentrations in HAB rats were found. In contrast to ACTH, corticosterone and prolactin, plasma oxytocin and vasopressin levels did not differ between HAB and LAB animals; oxytocin, but not vasopressin, responding to open arm exposure with a significant increase in both lines (P<0.05). In conclusion, particularly due to the association between inborn anxiety and HPA axis hyper-reactivity, the HAB rat represents a promising animal model for further investigation of the relationship between emotional disturbance and neuroendocrine activity.

Brain oxytocin inhibits basal and stress-induced activity of the hypothalamo-pituitary-adrenal axis in male and female rats: partial action within the paraventricular nucleus.

Oxytocin is a classic reproductive neuropeptide in the female mammal, but its functions in the brain of the male have been less well studied. As stress induces intracerebral oxytocin release independently of gender, we postulated that central oxytocin may play a role in the control of stress responses. In both male and virgin female rats, oxytocin receptor blockade in the brain by intracerebral infusion of a selective oxytocin antagonist (des Gly-NH2 d(CH2)5 [Tyr(Me)2, Thr4] OVT; 0.75 microgram/5 microliter increased the activity of the hypothalamo-pituitary-adrenal (HPA) axis as indicated by a significantly enhanced basal and stress-induced (exposure to the elevated plus-maze, forced swimming) secretion of corticotropin (ACTH) and corticosterone into blood. The anxiety-related behaviour on the plus-maze was not altered by the antagonist in either males or females. Infusion of the oxytocin antagonist into the hypothalamic paraventricular nucleus by reversed microdialysis resulted in a significant increase in basal release of ACTH in both male and virgin female rats. These results demonstrate a novel, gender-independent physiological function of endogenous brain oxytocin in the regulation of neuroendocrine stress responses. Under basal conditions, the inhibition of the HPA axis occurs, at least in part, within the paraventricular nucleus.

Attenuation of hypothalamic-pituitary-adrenal axis stress responses in late pregnancy: changes in feedforward and feedback mechanisms.

The hypothalamic-pituitary-adrenal axis is hyporesponsive to stress in late pregnancy, exemplified as reduced adrenocorticotropic hormone (ACTH) and corticosterone responses to restraint, but the mechanisms are unknown. We investigated forward drive and negative feedback upon the hypothalamic-pituitary-adrenal axis in pregnant rats. Corticotropin-releasing hormone (CRH) and vasopressin mRNA expression in the parvocellular paraventricular nucleus and mineralocorticoid and glucocorticoid receptor expression in the paraventricular nucleus and hippocampus were quantified with in situ hybridization. Because it can enhance the corticosterone negative feedback signal, 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) bioactivity in these brain regions and anterior pituitary was measured in vitro, and ACTH and corticosterone stress responses were measured after intracerebroventricular glycyrrhetinic acid, an 11beta-HSD inhibitor. Changes in corticosterone feedback on ACTH secretion were examined after pharmacological adrenalectomy by metyrapone and aminoglutethimide. Parvocellular paraventricular nucleus CRH mRNA content was reduced on day 21 and the CRH mRNA : vasopressin mRNA ratio was unaltered, indicating decreased production of both CRH and vasopressin. An increase in glucocorticoid receptor mRNA expression in the dentate gyrus (mineralocorticoid receptor mRNA expression was unaltered) and increased 11beta-HSD1 activity in the paraventricular nucleus and anterior pituitary suggest an increase in slow negative feedback mechanisms in pregnancy, but glycyrrhetinic acid did not modify the stress response. After metyrapone/aminoglutethimide treatment, corticosterone decreased ACTH secretion more slowly in pregnancy, indicating a decrease in rapid feedback sensitivity. Thus, reduced forward drive rather than increased effectiveness of glucocorticoid negative feedback may underlie stress hyporesponsiveness of the hypothalamic-pituitary-adrenal axis in pregnancy.

Dimensions of emotionality in a rat model of innate anxiety.

Emotionality is thought to be multidimensional, with "anxiety" representing one dimension. Dissecting emotional dimensions in animal models is an essential prerequisite for investigating the neurobiological mechanisms that underlie anxiety. The authors used factor analysis to investigate emotional dimensions in normal rats and rats bred for either high or low anxiety-related behavior. Hyperanxious rats were reduced in emotional dimensions in the elevated plus-maze by selection pressure, and a modified hole board test revealed a dissection of their emotionality with precisely defined dimensions. This enabled clear differentiation of "anxiety" from other emotional dimensions including risk assessment behavior and exploration. Factors extracted by analyzing data from a multiple-test battery corresponded to particular test characteristics rather than to emotional dimensions. The approach used might help to develop specific treatment strategies for anxiety disorders.

Unconditioned anxiety and social behaviour in two rat lines selectively bred for high and low anxiety-related behaviour.

Individuals of high anxiety-related behaviour (HAB) and low anxiety-related behaviour (LAB) rat lines were selectively bred for differences in anxiety-related behaviour on the elevated plus-maze. The goal of this study was to investigate whether this behavioural difference is restricted to the test used as the selection criterion or whether it is a stable and robust trait also in other conflict or non-conflict situations. Therefore, behaviour of male and female HAB and LAB rats was examined in two further tests of unconditioned anxiety: the black-white box and the social interaction test. Furthermore, behaviour of group-housed male HAB and LAB rats was studied in their home cages. In addition to standard statistics, discriminant analyses were performed. The difference in anxiety-related behaviour between the two lines was highly consistent in all tests of unconditioned anxiety. There were also differences in home cage behaviour, LAB rats being more active than HAB rats; this is likely to be a consequence of the LAB rats displaying a higher aggressiveness in social behaviour, compared to HAB rats. In all tests used HAB and LAB rats were clearly distinguished by discriminant analysis. However, while in the elevated plus-maze and the black-white box test the most important parameters for discrimination between the two lines were mainly those generally seen as closely related to anxiety, the discrimination in the social interaction paradigm was primarily due to differences in locomotor activity.

Periodic maternal deprivation induces gender-dependent alterations in behavioral and neuroendocrine responses to emotional stress in adult rats.

There is evidence that stressful events during the neonatal "stress hyporesponsive period" may influence both emotional behavior and the maturation of the hypothalamic-pituitary-adrenal (HPA) axis in rats. We tested whether periodic maternal deprivation (180 min daily on postnatal days 3-10, PMD) caused chronic changes in emotional behavior and HPA axis activity in either male or female adult rats, or both. In addition, HPA secretory responses to human/rat corticotropin-releasing factor (CRH, 50 ng/kg i.v.) were determined in the adult males. In the elevated plus-maze test, adult (4-5 months of age) PMD-treated animals of both sexes displayed increased anxiety-related behavior compared to control rats. This was indicated by a reduction in the number of entries (male: 70% reduction, p < 0.01; female: 31% reduction, p < 0.01) and amount of time spent on the open arms (male: 86% reduction, p < 0.01; female: 40% reduction, NS). Neuroendocrine parameters were also altered in PMD-treated rats in a gender-dependent manner. Whereas basal plasma adrenocorticotropin (ACTH) and corticosterone levels did not differ significantly between PMD and control groups of either sex, the ACTH response to elevated plus-maze exposure, a predominantly emotional stressor, was higher in male (p < 0.01), but not female, PMD animals than in the respective controls. In contrast, PMD had no effect on behavioral (duration of struggling) or HPA axis responses to forced swimming (90 s, 19 degrees C), a complex and predominantly physical stressor, in either male or female rats. In response to CRH stimulation, PMD-treated males did not show differences in the ACTH secretion compared to controls, indicating alterations in HPA axis regulation at a suprapituitary level. Thus, PMD caused long-term changes in the emotional behavior of adult rats of both sexes, although to a differing degree in males and females, whereas it appeared to cause predominantly alterations in the HPA axis response in males, depending on the characteristics of the stressor used.

Pharmacological characterisation of cortical gamma-aminobutyric acid type A (GABAA) receptors in two Wistar rat lines selectively bred for high and low anxiety-related behaviour.

Two Wistar rat lines that have been selectively bred for high-anxiety-related behaviour (HAB) and low-anxiety-related behaviour (LAB) in the elevated plusmaze test may be considered as a genetically prone animal model to study the neurochemical correlates of anxiety-related behaviour. Because there are pronounced differences between the two lines both in baseline levels of open-arm exploration in the elevated plus-maze test and in sensitivity to the anxiolytic effects of 1 mg/kg diazepam, we used these lines to investigate the pharmacology of the benzodiazepine binding site and the GABA binding site of cortical GABAA receptors. No difference in characteristics of flunitrazepam, zolpidem or muscimol binding to cortical GABAA receptors could be detected between the two lines. Although there was an increase in the brain concentration of the anxiolytic neuroactive steroid allopregnanolone, a potent positive allosteric modulator of GABAA receptors, both in HAB and LAB animals after a forced swim stress, allopregnanolone concentrations did not differ between the two lines. Moreover, plasma dehydroepiandrosterone (DHEA) concentrations were similar in HAB and LAB animals. We conclude that anxiety-related behaviour and benzodiazepine sensitivity in these rat lines are likely to be independent of the pharmacology of cortical GABAA receptors.

Ultrasound-aided diagnosis of an insulinoma in a cat.

A 15-year old, neutered female, domestic shorthaired cat was presented for evaluation of a 3-month history of paroxysmal falling over and trembling. In laboratory work the cat displayed a mild hypoglycemia. Ultrasound revealed a nodule in the left pancreatic lobe and surgical excision was performed. The histological diagnosis was an insulinoma. To the authors knowledge this is the first ultrasound description of an insulinoma in a cat. Up to date the cat has a survival time of 32 months without recurrence of symptoms.

[Computed tomography in cats with craniofacial trauma with regard to maxillary and orbital fractures]. / Computertomographische Untersuchung des Schädels von Katzen mit kraniofazialem Trauma im Hinblick auf Maxilla- und Orbitafrakturen.

OBJECTIVE: Computed tomographic examination of the skull of cats with craniofacial trauma. Analysis of diagnostic findings with regard to the occurrence of isolated and combined maxillary and orbital fractures. MATERIAL AND METHODS: Prospective study (August 2006 - June 2010): Computed tomography (CT) of the skull of cats with craniofacial trauma. RESULTS: Thirty-eight cats met the inclusion criteria. Breeds were 36 Domestic Shorthair cats, one Maine Coon and one Somali cat. Age at admission ranged from 11 to 187 months. The ratio of the numbers of males to females was 22:16 (1.4). Computed tomographic examination revealed a maxillary fracture in 27 (71%) animals. Sixteen (42%) cats had multiple maxillary fractures (≥2). Twenty-eight animals (74%) displayed orbital fractures. Combined maxillary and orbital fractures occurred in 26 (68%) patients. The odds ratio of this combined occurrence was 87 (p<0.001). Sixteen (57%) of 28 cats with orbital fractures showed multiple orbital fractures (≥2). The incidence of bilateral orbital fractures was 67% (25 patients). The medial orbital wall was the most commonly fractured orbital wall (66%), and the orbital floor the second most common (61%). CONCLUSION: Computed tomographic examination of the skull of cats with craniofacial trauma showed that maxillary and orbital fractures are more common than previously described. Combined maxillary and orbital fractures occurred in more than half of the patients. In cats, orbital fractures mainly affect the medial orbital wall and the orbital floor. CLINICAL RELEVANCE: Cats with craniofacial trauma often have maxillary and orbital fractures. The additional information taken from the computed tomographic examination could lead to an optimised therapeutical concept.