排序方式: 共有8条查询结果,搜索用时 0 毫秒
1
1.
Christopher J Bonar Albert H Lewandowski Baha Arafah Charles C Capen 《Journal of zoo and wildlife medicine》2005,36(4):719-723
A 43 yr-old female African elephant (Loxodonta africana) collapsed acutely and died. Necropsy revealed an enlarged right adrenal medulla. Histologic appearance was typical of pheochromocytoma. Special stains and electron microscopy demonstrated chromaffin granules, suggesting that the tumor was derived from catecholamine secreting cells of the adrenal medulla, and may have been functionally secretory. Serum levels of both norepinephrine and epinephrine were elevated at time of death, supporting the functional nature of the tumor. Histologic findings of arteriolar sclerosis and smooth muscle hyperplasia suggested that the animal may have suffered from chronic systemic hypertension. Pheochromocytoma should be considered as a differential diagnosis in cases of suspected hypertension and acute death in elephants. 相似文献
2.
We report the impact of human-induced desertification on the species richness, abundance, and composition of sand dune flora and herpetofauna of North Sinai, Egypt. Our hypothesis was that degraded habitats would have reduced vegetation complexity, richness, and abundance, and consequently lower reptile species richness and abundance. We also hypothesized that desert lizards would not follow the typical generalist/specialist responses to habitat degradation found in other biomes. Instead, we predicted that because vegetation loss intensifies the environmental extremity of deserts, those species specialized for open and sandy environments would be more likely to persist in desertified habitats than would desert generalists. Our results showed that areas protected from vegetation loss did not have significantly higher vegetation richness or abundance except for only a few species. However, protected sites did have significantly higher percent vegetation cover and height. Habitat protection clearly had strong effects on the reptile community as species richness and abundances were significantly higher in protected sites. The composition of the reptile community between protected and unprotected sites differed significantly. Contrary to past studies in other environments, desert generalist species were not able to persist in degraded sites and were only found in protected sites. Specialist species were ubiquitous in that they occurred in both areas protected and unprotected from vegetation loss. We propose that the effects of disturbance on species composition (specialists or generalists) depends on whether the disturbance exacerbates or reduces environmental harshness and the conditions that favor specialization. In extreme environments, specialist and generalist responses to habitat degradation are opposite to that of more productive environments. 相似文献
3.
4.
5.
6.
Summary The output of first stage Protostrongvlid larvae of sheep was studied in natural infections. Three sets of observations were obtained from October 1977 to December 1978 in three regions. The larval output varied with the species harboured by sheep and with the density of worm populations. Anthelmintic treatments influenced the fecundity of worms. The age of the animals was an important cause of variation in the size of larval output; a rise of the latter was observed in pregnant ewes at the period of lambing. A seasonal variation in output was recorded. The fauna was characterized by the high prevalence of Muellerius and Neostrongylus. 相似文献
7.
Onağ Ali Oksel Figen Taneli Baha Hakerlerler Hüseyin 《Water, air, and soil pollution》1998,105(3-4):661-665
Lead additives in automotive fuel, smog from a nearby industrial center warranted an investigation on cadmium and lead in Manisa, a city of tabacco processing. Hundred and one children were screened in view of lead and cadmium exposure. In 23 children between the ages of 0–2 years the mean (±SEM) serum lead level was 7.15 ± 0.10 μg/dl, in 28 between the ages of 3–6 years was 7.20 ± 0.10 μg/dl and in 50 between the ages of 7–15 years was 7.20 ± 0.10 μg/dl, respectively, with no significant differences. Serum cadmium levels in the same groups of children was 0.066 ± 0.008 ng/ml, 0.078 ± 0.008 ng/ml 0.088 ± 0.006 ng/ml, respectively. The difference in cadmium levels between the age groups of 0–2 years and 7–15 years was significant (p<0.038). This significant increase in blood cadmium level is also shown by simple linear regression analysis: Cadmium (ng/ml) = 0.049 + 0.005 (age), and p<0.0001, F Ratio = 50.578, coefficient of correlation = 0.581. Our study revealed that lead is not a serious environmental contaminant for children, yet; however, the increasing trend seen in exposure to cadmium warrants serious consideration and urgant preventive measures. 相似文献
8.
1