Plains zebra (Equus quagga) adrenocortical activity increases during times of large aggregations in the Serengeti ecosystem.

Adverse environmental stimuli (stressors) activate the hypothalamic-pituitary-adrenal axis and contribute to allostatic load. This study investigates the contribution of environmental stressors and life history stage to allostatic load in a migratory population of plains zebras (Equus quagga) in the Serengeti ecosystem, in Tanzania, which experiences large local variations in aggregation. We expected higher fGCM response to the environmental stressors of feeding competition, predation pressure and unpredictable social relationships in larger than in smaller aggregations, and in animals at energetically costly life history stages. As the study was conducted during the 2016 El Niño, we did not expect food quality of forage or a lack of water to strongly affect fGCM responses in the dry season. We measured fecal glucocorticoid metabolite (fGCM) concentrations using an enzyme immunoassay (EIA) targeting 11ß-hydroxyetiocholanolone and validated its reliability in captive plains zebras. Our results revealed significantly higher fGCM concentrations 1) in large aggregations than in smaller groupings, and 2) in band stallions than in bachelor males. Concentrations of fGCM were not significantly higher in females at the energetically costly life stage of late pregnancy/lactation. The higher allostatic load of stallions associated with females, than bachelor males is likely caused by social stressors. In conclusion, migratory zebras have elevated allostatic loads in large aggregations that probably result from their combined responses to increased feeding competition, predation pressure and various social stressors. Further research is required to disentangle the contribution of these stressors to allostatic load in migratory populations.

Female mate-choice drives the evolution of male-biased dispersal in a social mammal.

Dispersal has a significant impact on lifetime reproductive success, and is often more prevalent in one sex than the other. In group-living mammals, dispersal is normally male-biased and in theory this sexual bias could be a response by males to female mate preferences, competition for access to females or resources, or the result of males avoiding inbreeding. There is a lack of studies on social mammals that simultaneously assess these factors and measure the fitness consequences of male dispersal decisions. Here we show that male-biased dispersal in the spotted hyaena (Crocuta crocuta) most probably results from an adaptive response by males to simple female mate-choice rules that have evolved to avoid inbreeding. Microsatellite profiling revealed that females preferred sires that were born into or immigrated into the female's group after the female was born. Furthermore, young females preferred short-tenured sires and older females preferred longer-tenured sires. Males responded to these female mate preferences by initiating their reproductive careers in groups containing the highest number of young females. As a consequence, 11% of males started their reproductive career in their natal group and 89% of males dispersed. Males that started reproduction in groups containing the highest number of young females had a higher long-term reproductive success than males that did not. The female mate-choice rules ensured that females effectively avoided inbreeding without the need to discriminate directly against close kin or males born in their own group, or to favour immigrant males. The extent of male dispersal as a response to such female mate preferences depends on the demographic structure of breeding groups, rather than the genetic relatedness between females and males.

Effects of providing total mixed rations indoors and on pasture on the behavior of lactating dairy cattle and their preference to be indoors or on pasture.

Grazing is considered a normal behavior for dairy cattle, although they may not be able to meet their nutritional requirements from grazing alone, and so to sustain higher yields requires access to a total mixed ration (TMR). The study aim was to provide dairy cows with access to TMR indoors and on pasture to establish influence on behavior and preference for each location. The study took place from August to November, 2009, using 36 late-lactation Holstein-Friesian dairy cows. The cows were allocated to 1 of 3 26-d study periods (n=12×3). Within each period the cows were further divided into a control (n=6) or treatment (n=6) group using a crossover design, where the cows were changed between the control and treatment group after 13 d. Treatment cows had access to TMR indoors and on pasture, whereas control cows only had access to TMR indoors. Following a.m. and p.m. milkings the cows were taken to a point equidistant between indoors and pasture and given the choice of going to pasture (1.5 ha) or to a freestall barn. Between milkings the cows had free access between the locations. Initial choice was recorded and a video camera was used to record time spent in each location. Behavior observations were recorded to establish how the cows spent their time during the day. To determine what factors influenced preference, weather conditions, milk yield, body condition score, and lameness were recorded. Initially, the cows chose indoors following milking (96.4±0.80%). Overall, the cows expressed a partial preference for pasture (71.1±1.82%), which was different from 100, 50, and 0%. Study period influenced preference with cows spending less time on pasture as the season progressed (86.7 vs. 68.3 vs. 58.3% for study periods 1, 2, and 3, respectively). Providing the cows with TMR outdoors did not affect pasture use, but resulted in an increase in TMR intake of 2.2±0.41 kg of dry matter/d. The cows spent more time on pasture as the temperature-humidity index indoors (55.6±0.92) and outdoors (54.6±0.82) increased, but rainfall and milk yield did not influence preference. Cows with lameness score >1.5 spent more time indoors (35.4±4.52 vs. 25.2±2.64% for cows with >1.5 vs. ≤1.5 lameness score, respectively). In conclusion, the cows expressed a partial preference for pasture, which was not influenced by providing TMR on pasture.

Lymphoscintigraphy in melanoma: initial evaluation of a low protein dose monoclonal antibody cocktail.

A low protein dose (73 +/- 10 micrograms total) 131I-labeled monoclonal antibody cocktail made of equal microgram quantities of 225.28S (IgG2a) and 763.24T (IgG1) murine monoclonal antibodies, which bind additively to a high molecular weight antigen of melanoma, was evaluated as a lymphoscintigraphic agent in 17 patients with intermediate to thick (mean Breslow depth, 3.39 +/- 0.64 mm) melanomas or clinical Stage II disease scheduled for nodal dissection. Eleven of the patients were clinically Stage I while 6 were clinically Stage II. 131I antibody cocktail, 258 +/- 10 microCi, was administered s.c. at the site of the primary melanoma or its scar following surgical removal. In eight patients, 63 +/- 8 microCi of 125I nonspecific normal sheep IgG was coadministered s.c. Gamma camera imaging was conducted beginning immediately after and continuing for several days following injection. Surgical resection, weighing, and gamma counting of the draining lymph nodes were undertaken in all patients. On gamma scans, early nodal uptake of antibody was most pronounced and of longest duration in the tumor pathologically positive patients (5 of 7 had visible nodal uptake, 4 of 7 visually stable or rising with time), with the t 1/2 of nodal clearance by gamma scan significantly (P less than 0.05) longer than in the negative patients in whom 4 of 10 showed some, although generally transient (0 of 10 stable or rising), nodal uptake. Scans were not easily interpretable when the injection site was very near the draining nodal group, in part due to the detection of scatter activity from the injection site. In several instances the scan was correct and the clinical examination was incorrect as regards nodal disease. Quantitative analysis of the surgically excised draining nodes showed significantly (P less than 0.001) more 131I anti-melanoma antibody uptake in the 21 tumor-involved nodes [0.01217% injected dose (ID)/node median] than in the 512 tumor-negative nodes (0.00051% ID/node median). Median percentage ID/g of anti-melanoma antibody in tumor-involved nodes was significantly greater (P less than 0.01) than in tumor-negative nodes (0.01984 versus 0.003215% ID/g). 125I-labeled nonspecific antibody did not accumulate significantly more in the tumor-involved nodes on a per node or per g basis in the 283 of 533 nodes studied using the dual-label approach (0.0036 versus 0.00092% ID/g). These data demonstrate that by external imaging and by tissue counting that a radiolabeled anti-melanoma monoclonal antibody cocktail can specifically accumulate to melanoma-involved lymph nodes following s.c. administration.(ABSTRACT TRUNCATED AT 400 WORDS)

Demography, extinction and intervention in a small population: the case of the Serengeti wild dogs.

The effects of ecological factors (prey, competitors, predators and disease) and intervention (immobilization, radio-collaring, and vaccination) on population size and demography were investigated in Serengeti wild dogs (Lycaon pictus), an endangered canid, between 1965 and 1991. Variation in ecological factors explained most changes in demography, but did not explain a decline in adult longevity. A significant reduction in pack life and individual longevity was coincident with the introduction of routine intervention and consistent with pathogen-induced mortality. Survival varied significantly between categories of intervention, and between individuals likely to have been exposed to different degrees of social stress before intervention. The loss of all study packs in 1991 contrasted with the persistence of breeding packs outside the study area. The cause of the demise of most study packs is unknown. Monte Carlo simulations demonstrated that population extinction was unlikely to be the consequence of chance events alone. One explanation compatible with the evidence is an outbreak of viral disease induced by stress, possibly caused by intervention.

Population dynamics, intervention and survival in African wild dogs (Lycaon pictus).

The demography of Serengeti wild dog study packs and their extinction in 1991 was documented by Burrows et al. (1994). One explanation for pack loss compatible with demographic evidence was viral disease induced by stress caused by intervention (vaccination, immobilization and radio-collaring). Several studies claim to reject this hypothesis. However, cortisol levels measured in immobilized Lycaon, whose pathogen exposure is unknown, do not demonstrate that interventions in the Serengeti were benign. The analysis of survivorship in Lycaon in other ecosystems minimized the chance of demonstrating any effect of intervention and failed to consider vaccinations as intervention. There is now evidence that intervention significantly decreased survivorship of Masai Mara Lycaon. Further simulations of the likelihood of population extinction in Serengeti Lycaon, evidence of limited population variability and a small scaling factor in Serengeti Lycaon strengthen Burrows et al.'s conclusion that the extinction was unlikely to be due to chance alone. Although some studies claim that Lycaon conservation is doomed without intervention, to date vaccinations, blood sampling and radio-telemetry have contributed little to Lycaon conservation. All studies fail to disprove the Burrows hypothesis or provide convincing alternatives.

Social, state-dependent and environmental modulation of faecal corticosteroid levels in free-ranging female spotted hyenas.

Little is known about to what extent the sensitivity of the hypothalamic-pituitary-adrenal (HPA) axis may be state dependent and vary in the same species between environments. Here we tested whether the faecal corticosteroid concentrations of matrilineal adult female spotted hyenas are influenced by social and reproductive status in adjacent ecosystems and whether they vary between periods with and without social stress. Females in the Serengeti National Park frequently become socially subordinate intruders in other hyena territories by undertaking long-distance foraging trips to migratory herds, whereas in the Ngorongoro Crater they usually forage inside their own small territories on resident prey. The faecal corticosteroid concentrations in Serengeti females were significantly higher than in Ngorongoro females. Energy expenditure by lactation is exceptionally high in spotted hyenas and this may be reflected in their corticosteroid levels. The faecal corticosteroid levels in both populations were higher in lactating than in non-lactating females. During periods of social stability, faecal corticosteroid concentrations increased in non-lactating females but not in lactating females as social status declined. Lactating Serengeti females had significantly higher faecal corticosteroid concentrations during periods with acute severe social stress than during periods without, indicating that the HPA axis is sensitive to social stimuli even in lactating females. So far few studies have used non-invasive monitoring methods for assessing social stress in freeranging animals. This study demonstrates for the first time, to the authors' knowledge, that corticosteroid concentrations may differ between periods with and without social stress for a free-ranging female mammal and that the modulating effect of social status may depend on reproductive status.

Preschool vision screening: negative predictive value for amblyopia.

BACKGROUND/AIMS: Single optotype tests of visual acuity are widely used for preschool vision screening in order to optimise cooperation with testing. These tests may, however, underestimate the visual acuity deficit in amblyopia because they lack visual crowding. This study assessed the resultant negative predictive value (NPV) for amblyopia. METHODS: Cohort study of 936 children in the Cambridge Health District selected by date of birth. The presence of amblyopia among children who had passed preschool vision screening was determined using Snellen line acuity as the reference test. Preschool vision screening was conducted at 3.5 years of age by community orthoptists. The screening assessment comprised Sheridan-Gardiner single optotype test of visual acuity (referral criterion 6/9 or worse in either eye), cover test, ocular movements, 20(Delta) prism test, and TNO stereotest. RESULTS: The overall NPV of preschool vision screening for amblyopia was 100% (95% CI 99.4% to 100%). Most children with amblyopia were detected by the Sheridan-Gardiner single optotype test of visual acuity, but the other screening tests were necessary to prevent any false negatives. In isolation, the Sheridan-Gardiner single optotype test of visual acuity has a NPV for amblyopia of only 99.6% (95% CI 98.7% to 99.9%). CONCLUSION: Preschool vision screening using a single optotype test of visual acuity does achieve a high NPV for amblyopia, but only under certain conditions. These comprise a low threshold for referral (6/9 or worse in either eye) and the inclusion of a cover test and tests of binocular function in the screening assessment.

Pilot study of intra-arterial cisplatin and intravenous vinblastine and dacarbazine in patients with melanoma in-transit metastases.

For melanoma, in-transit metastases (ITMs) are a harbinger of systemic disease in over 70% of patients and thus warrant a systemic approach to management. In this study, previously untreated patients with ITMs (n=15) received a systemic regimen of 'CVD' in 21 day cycles (median, three cycles) as follows: dacarbazine 800 mg/m2 intravenously (i.v.) on day 1, vinblastine 1.6 mg/m2 i.v. on days 1-5, and cisplatin (CDDP) 100 mg/m2 by 24 h intra-arterial (i.a.) infusion in 1l of heparinized saline via the iliac or subclavian artery on day 3. There were three clinical complete responses (CRs) in patients with a modest burden of ITMs (< 3 cm in size) and seven partial responses (PRs), yielding a 67% response rate (95% confidence interval, 38-88%). One of the clinical CRs had microscopic residual disease at surgery (a pathological PR). The times to progression (TTP) for the CRs were 5, 21 and 38+ months; the median TTP for the PRs was 4.5 months (range, 2-10 months). Overall median survival was 31 months. Systemic toxicities were similar to those induced by i.v. CVD. However, patients noted more pronounced paraesthesia in the infused extremity. Also, two patients experienced severe CDDP-induced burns, one patient developed brachial plexopathy, and one patient had a haemorrhage in an occult brain metastasis. The high clinical activity of this regimen will have to be confirmed in more patients before a first-pass i.a. advantage can be claimed. Furthermore, the dose, schedule and technique of i.a. CDDP delivery must be further refined before it can be routinely incorporated in regimens as an alternative to isolated regional hyperthermic perfusion, which is technically more difficult and is not readily available in community-based hospitals.

Prevalence of amblyopia among defaulters of preschool vision screening.

The prevalence of amblyopia among screening defaulters is an important determinant of the efficacy of amblyopia detection by preschool vision screening. A retrospective cohort study was therefore performed to assess an orthoptist-based preschool vision screening programme. The preschool vision screening status of children in the cohort was determined by reviewing their Community Child Health records. The prevalence of amblyopia among screening defaulters was determined by reviewing each child's school entry vision test (performed at 5.5 years of age), with retesting if a Snellen line acuity of 6/6 in each eye had not been documented. For comparison, the prevalence of amblyopia among screening attenders was also determined. The preschool vision screening status was known for 86.0% (772/898) of the cohort. The attendance rate at preschool vision screening was 79.2%. The prevalence of amblyopia among screening defaulters was 1.3% (95% CI 0.2% to 4.5%). The prevalence of amblyopia among screening attenders was 2.5% (95% CI 1.4% to 4.1%). There was no significant difference in the prevalence of amblyopia between screening defaulters and screening attenders (P=0.53). The efficacy of amblyopia detection by preschool vision screening is therefore highly dependent on its attendance rate. Preschool vision screening programmes with a low attendance rate will fail to detect a significant proportion of children with amblyopia.

Canine distemper virus infection in Serengeti spotted hyenas.

Clinical signs suggestive of canine distemper virus (CDV) infection were observed among a group of spotted hyenas (Crocuta crocuta) in the Serengeti, Tanzania. Virus antigen was detected immunohistologically in a brain sample from a diseased cub. The presence of virus RNA could be demonstrated in this brain as well as in intestine and lymph node of the animal by RT-PCR. Sequence comparison of brain-derived amplicons showed that the virus was related to recent CDV field isolates. The closest homology (>99 percent) was to a recently described CDV which caused high mortality in sympatric lions.

Genetic characterization of canine distemper virus in Serengeti carnivores.

The lion (Panthera leo) population in the Serengeti ecosystem was recently afflicted by a fatal epidemic involving neurological disease, encephalitis and pneumonia. The cause was identified as canine distemper virus (CDV). Several other species in the Serengeti were also affected. This report presents CDV H and P gene sequences isolated from Serengeti lions (Panthera leo), spotted hyenas (Crocuta crocuta), bat-eared fox (Otocyon megalotis) and domestic dog (Canis familiaris). Sequence analyses demonstrated that the four Serengeti species carry closely related CDV isolates which are genetically distinct from other CDV isolates from various species and locations. The results are consistent with the conclusions that: (1) a particularly virulent strain of CDV emerged among Serengeti carnivores within the last few years; (2) that strain has recognizable shared-derived (synapomorphic) genetic differences in both H and P genes when compared to CDV from other parts of the world; and (3) that the CDV strain has frequently crossed host species among Serengeti carnivores.

Worry and the suppression of imagery.

This experiment investigates Borkovec's theory that the function of worry is to protect people from potentially distressing emotional imagery. The experiment builds on a previous one of Borkovec and Inz (Behaviour Research and Therapy, 28, 153-158, 1990) comparing the frequency of thoughts and images in imagery and relaxation. The present experiment confirms the previous finding that worry is associated with less imagery than relaxation, but shows that this is not distinctive to worry. Indeed, an additional control condition, 'present-oriented mentation', was associated with even less imagery than worry. The fact that other kinds of thinking are at least as effective as worry in suppressing emotional imagery indicates that this property of worry is not sufficient to explain its occurrence.

The contribution of worry to insomnia.

Recent research has pointed to the importance of cognitive activity in interfering with sleep, and suggested a close relationship between worry and insomnia. To explore the relationship between worry and insomnia in more detail, a sample was studied in which worry and insomnia were combined in a 2 x 2 design. The content of sleep-interfering cognitions was explored both with a previously developed Sleep Disturbance Questionnaire and a newly developed checklist of the content of thoughts that arose if people could not sleep. Both supported the importance of a distinction between sleep-related and other thoughts. Whereas worried insomniacs show a broad range of sleep-interfering thoughts, the thoughts of non-worried insomniacs focused mainly on sleep itself.

Faecal fistula as the result of thermal injury to the abdominal wall.

A 23-year-old male with an 87 per cent body surface area burn from a motor vehicle accident developed a left lower quadrant abdominal wall faecal fistula. This fistula presumably resulted from thermal injury to the level of the peritoneum. This case report describes the course and management of this unusual occurrence.

Comparative costs of laparoscopically assisted vaginal hysterectomy.

AIM: To audit the performance of laparoscopically assisted vaginal hysterectomy (LAVH) in a gynaecological practice with regard to cost and clinical outcome when compared to the surgical alternatives available. METHOD: LAVH was performed on 50 women and both monetary and time cost parameters analysed and compared with those of 30 women undergoing either abdominal hysterectomy, vaginal hysterectomy or endometrial resection. RESULTS: The cost of LAVH was approximately twice that of abdominal hysterectomy and almost three times that of vaginal hysterectomy. The theatre time was longer for LAVH than for the above and in a similar ratio. Patient recovery was superior with LAVH when compared with abdominal hysterectomy but not when compared with standard vaginal hysterectomy. CONCLUSION: LAVH has a role in providing patients with the option of avoiding abdominal hysterectomy, although the role will differ depending upon the differing criteria used by surgeons for selecting patients for standard vaginal hysterectomy.

Polar bear encephalitis: establishment of a comprehensive next-generation pathogen analysis pipeline for captive and free-living wildlife.

This report describes three possibly related incidences of encephalitis, two of them lethal, in captive polar bears (Ursus maritimus). Standard diagnostic methods failed to identify pathogens in any of these cases. A comprehensive, three-stage diagnostic 'pipeline' employing both standard serological methods and new DNA microarray and next generation sequencing-based diagnostics was developed, in part as a consequence of this initial failure. This pipeline approach illustrates the strengths, weaknesses and limitations of these tools in determining pathogen caused deaths in non-model organisms such as wildlife species and why the use of a limited number of diagnostic tools may fail to uncover important wildlife pathogens.