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Zimmerman PA; Katholi CR; Wooten MC; Lang-Unnasch N; Unnasch TR 《Molecular biology and evolution》1994,11(3):384-392
Polymerase chain reaction (PCR) products were characterized for a repeated
sequence family (designated "O-150") of the human filarial parasite
Onchocerca volvulus. In phylogenetic inferences, the O-150 sequences
clustered into closely related groups, suggesting that concerted evolution
maintains sequence homology in this family. Using a novel mathematical
model based on a nested application of an analysis of variance, we
demonstrated that African rainforest and savannah strain parasite
populations are significantly different. In contrast, parasites collected
in the New World are indistinguishable from African savannah strains of O.
volvulus. This finding supports the hypothesis that onchocerciasis was
recently introduced into the New World, possibly as a result of the slave
trade.
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Dawood T Williams MR Fullerton MJ Myles K Schuijers J Funder JW Sudhir K Komesaroff PA 《Regulatory peptides》2005,125(1-3):47-53
Stress is an important contributor to cardiovascular disease and to reduced immunity and fertility. As the role of androgens in stress is uncertain, we investigated the effects of testosterone (T) on hormonal responses to stress in conscious Romney Marsh wethers. Six T-treated sheep and six control sheep were stressed by exposure to a psychological and a metabolic stimulus. Baseline glucose levels were significantly lower in the treated animals compared with controls (p=0.002). T treatment significantly attenuated ACTH (p<0.01) and cortisol (p<0.05) responses to metabolic stress. Following psychological stress, ACTH responses were significantly lower in treated sheep compared with controls (p<0.05), but differences in mean cortisol responses did not reach significance. There were no significant differences in epinephrine or norepinephrine responses following either stressor. We conclude that T replacement in wethers lowers glucose and attenuates responses to metabolic and psychological stress. While the implications of these results for human physiology require further studies, they suggest that male hypogonadism may play a role in determining the risk of cardiovascular disease and diabetes. 相似文献
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Shanhong Ling Ruizhi Luo Aozhi Dai Zhixin Guo Ruoling Guo Paul A. Komesaroff 《Phytomedicine》2009,16(1):56-64
Salvia miltiorrhiza is a medicinal herb commonly used in traditional Chinese medicine for the prevention and treatment of cardiovascular disease. This study investigated the effects of Cardiotonic Pill (CP), a pharmaceutical preparation of Salvia miltiorrhiza, on cardiac myocytes and fibroblasts with respect to the viability, proliferation, and collagen synthesis in these cells under various conditions. A cardiac myocyte line, H9c2, and primarily cultured fibroblasts from rat hearts were incubated with CP over a broad concentration range (50–800 μg/ml) under normal cultures, conditions of ischemia (serum-free culture), and stimulation by angiotensin II (AII, 100 nM), hydrogen peroxide (H2O2, 50–200 μM), or tumor necrosis factor α (TNFα, 40 ng/ml) for 24–48 h. Cell growth, apoptosis, DNA and collagen synthesis, and expression of relevant genes were assessed via cell number study, morphological examination, Annexin-V staining, flow-cytometry, [3H]-thymidine or [3H]-proline incorporation assay, and Western blotting analysis. It was found that (1) at therapeutic (50 μg/ml) and double therapeutic (100 μg/ml) concentrations, CP did not significantly affect normal DNA synthesis and cell growth in these cardiac cells, while at higher (over 4-fold therapeutic) concentrations (200–800 μg/ml), CP decreased DNA synthesis and cell growth and increased cell death; (2) CP treatment (50 μg/ml) significantly inhibited TNFα-induced apoptosis in myocytes, with 12.3±1.46% cells being apoptosis in CP treatment group and 37.0±7.34% in the control (p<0.01), and simultaneously, expression of activated (phosphorylated) Akt protein was increased by about 2 folds in the CP-treated cells; and (3) in cultured fibroblasts, CP significantly reduced AII-induced collagen synthesis in a concentration-dependent manner (by ~50% and ~90% reduction of AII-induced collagen synthesis at 50 and 100 μg/ml, respectively). Thus, Salvia miltiorrhiza preparation CP is physiologically active on cardiac cells. The actions by CP to reduce apoptotic damage in myocytes and collagen synthesis in fibroblasts may help to preserve the heart function and reduce heart failure risk. The actions by CP to inhibit DNA synthesis and cell growth, which occurred at over therapeutic doses, may weaken the ability of heart repair. Further studies are needed to identify the chemical compounds in this herbal product that are responsible for these observed physiological effects. 相似文献
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The African freshwater oyster Etheria elliptica, which is of great economic importance throughout the continent, is facing overharvesting in many fisheries in West Africa. Its reproductive traits (sex ratio, size at sexual maturity, oocyte diameter and fecundity) were studied at four stations located along the Pendjari River, northern Benin, in April 2013. Histological techniques were implemented to identify sex and gonad development stages. Oocyte sizes were measured based on the histological images and mean oocyte diameter was 38 µm. Fecundity, estimated by counting the developing eggs, averaged 106 724 eggs and increased significantly with shell size. The average sex ratio was approximately 1:1. Hermaphrodites were rare. Males reached sexual maturity at 57.6 mm dorsoventral height, earlier than females at 64.7 mm. The majority of the oyster specimens were in ripe-spawning stages, indicating that reproductive activities partly took place towards the end of the dry season. Both mature and immature individuals were subjected to harvesting at all the investigated fishing sites. The mean size of exploited oysters was 60.6 mm, lower than the size of females at maturity. Management strategies must enforce the minimum size of 65 mm required for harvesting, particularly in open access sites where juveniles are mostly harvested. 相似文献
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