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1.
Basal hypothalamic bilateral electrolytic lesions were placed in White Leghorn cockerels causing functional castration and obesity. Other cockerels were surgically castrated. Determinations were made of the reproductive traits, weight of abdominal adipose tissues, weight and fat content of livers, fat in muscles and bones, hematocrits, plasma calcium, triglycerides, cholesterol, and phospholipid phosphorus before and after injections of chicken pituitaries (CP) into cocks bearing hypothalamic lesions (HL), and before and after injections of testosterone propionate (TP) into surgically castrated (SC) cocks. Treatment of HL cocks with CP partially restored reproductive behavior, but abdominal massage produced only seminal fluid without spermatozoa. The weight of the abdominal adipose tissue was used as a measure of adiposity since it varies directly with total body fat. Adiposity in HL cocks was 2.5 times greater than that of SC cocks. Injections of CP into HL cocks reduced adiposity by 60%. In contrast, injections of TP into SC cocks reduced body fat to normal. Injections with CP into HL cocks reduced moderately the weights of the hypertrophied fatty livers and reduced fat content toward normal, but livers remained abnormal. In surgically castrated cocks, livers remained normal. Functional or surgical castration depressed blood hematocrit values. Injections with TP restored hematocrit values in SC cocks. In contrast, injections of CP into HL cocks were virtually without effect upon the depressed hematocrit values.  相似文献   

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Androgens and estrogens are known regulators of fetal and postnatal lung development, but their levels in the developing lung have never been determined. We present here, for the first time, a gas chromatography-mass spectrometry (GC/MS) quantification of dihydrotestosterone, testosterone, androstenedione, and estradiol in canalicular, saccular, and alveolar stage lungs of both sexes. Testosterone, androstenedione, and estradiol were observed in all the analyzed lung samples from gestation day (GD) 16.5 to postnatal day (PN) 30, totalizing 383 individual mice. Levels of these three steroids decreased between birth and PN 5. In contrast, dihydrotestosterone was detected only in male samples on GD 19.5, PN 0, and PN 30. A significant sex difference was observed for testosterone and androstenedione but not for estradiol. Steroid levels were also determined in skinned hind legs for comparison. Three-way analysis of variance revealed that tissue (lung or leg) had a significant effect on testosterone levels for both sexes, but not on androstenedione and estradiol levels. Low but significant testosterone and androstenedione levels were observed in all the females and in prepubertal male samples. These levels must be sufficient to induce androgen receptor activation, as suggested by our recent report showing the presence of androgen receptor in the nucleus of several lung cells in corresponding developmental ages and sexes.  相似文献   

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Several endothelial growth factors induce both blood and lymphatic angiogenesis. However, a systematic comparative study of the impact of these factors on vascular morphology and function has been lacking. In this study, we report a quantitative analysis of the structure and macromolecular permeability of FGF-2-, VEGF-A-, and VEGF-C-induced blood and lymphatic vessels. Our results show that VEGF-A stimulated formation of disorganized, nascent vasculatures as a result of fusion of blood capillaries into premature plexuses with only a few lymphatic vessels. Ultrastructural analysis revealed that VEGF-A-induced blood vessels contained high numbers of endothelial fenestrations that mediated high permeability to ferritin, whereas the FGF-2-induced blood vessels lacked vascular fenestrations and showed only little leakage of ferritin. VEGF-C induced approximately equal amounts of blood and lymphatic capillaries with endothelial fenestrations present only on blood capillaries, mediating a medium level of ferritin leakage into the perivascular space. No endothelial fenestrations were found in FGF-2-, VEGF-A-, or VEGF-C-induced lymphatic vessels. These findings highlight the structural and functional differences between blood and lymphatic vessels induced by FGF-2, VEGF-A, and VEGF-C. Such information is important to consider in development of novel therapeutic strategies using these angiogenic factors.  相似文献   

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The relation of in vitro lipophilicity, based on octanol:buffer partition ratio and on reverse-phase liquid chromatographic retention, to in vivo pharmacokinetics and central nervous system entry was evaluated for the beta-blockers propranolol, acebutolol, and sotalol. Anesthetized cats received single intravenous doses, following which plasma kinetics, cerebrospinal fluid (CSF) kinetics and brain tissue uptake were determined over the next 4 h. Propranolol, by far the most lipophilic beta-blocker in vitro, had the highest in vivo metabolic clearance and volume of distribution (Vd), the most rapid entry into CSF, and the highest brain:plasma uptake ratio (38.0). Sotalol, the most hydrophilic drug in vitro, had the lowest in vivo clearance and Vd, the slowest CSF entry, and the lowest brain:plasma ratio (0.52). Acebutolol had slightly greater in vitro lipophilicity than sotalol, intermediate values of in vivo plasma kinetics and CSF entry rate, and a slightly greater brain:plasma uptake ratio (0.71). Thus, differences among beta-blockers in lipid solubility are associated with predictable differences in plasma kinetics, and rate of entry into CSF. Furthermore, the relative extent of entry into brain is lower for hydrophilic as opposed to lipophilic beta-blockers.  相似文献   

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Phylogenetic analysis of DNA sequences from primates, rodents, lagomorphs, artiodactyls, carnivores, and birds strongly suggests that the order Rodentia is an outgroup to the other four mammalian orders and that Artiodactyla and Carnivora belong to a superordinal clade. Further, there is strong evidence against the Glires concept, which unites Lagomorpha and Rodentia. The radiation among Lagomorpha, Primates, and Artiodactyla--Carnivora is very bush-like, but there is some evidence that Lagomorpha has branched off first. Thus, the branching sequence for these five orders of mammals seems to be Rodentia, Lagomorpha, Primates, Artiodactyla, and Carnivora. The branching date for Rodentia could be as early as 100 million years ago. The rate of nucleotide substitution in the rodent lineage is shown to be at least 1.5 times higher than those in the other four mammalian lineages.  相似文献   

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Underlying causes, risk factors, and precipitating causes of heart failure (HF) should be treated. Drugs known to precipitate or aggravate HF such as nonsteroidal antiinflammatory drugs should be stopped. Patients with HF and a low left ventricular ejection fraction (systolic heart failure) or normal ejection fraction (diastolic HF) should be treated with diuretics if fluid retention is present, with an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin receptor blocker if the patient cannot tolerate an ACE inhibitor because of cough, angioneurotic edema, rash, or altered taste sensation, and with a beta blocker unless contraindicated. If severe systolic HF persists, an aldosterone antagonist should be added. If HF persists, isosorbide dinitrate plus hydralazine should be added. Calcium channel blockers should be avoided if systolic HF is present. Digoxin should be avoided in men and women with diastolic HF if sinus rhythm is present and in women with systolic HF. Digoxin should be given to men with systolic HF if symptoms persist, but the serum digoxin level should be maintained between 0.5 and 0.8 ng/mL.  相似文献   

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Ghrelin is a peptide predominantly produced by the stomach. Ghrelin displays strong GH-releasing activity. This activity is mediated by the activation of the so-called GH secretagogue receptor type 1a. This receptor had been shown to be specific for a family of synthetic, peptidyl and nonpeptidyl GH secretagogues. Apart from a potent GH-releasing action, ghrelin has other activities including stimulation of lactotroph and corticotroph function, influence on the pituitary gonadal axis, stimulation of appetite, control of energy balance, influence on sleep and behavior, control of gastric motility and acid secretion, and influence on pancreatic exocrine and endocrine function as well as on glucose metabolism. Cardiovascular actions and modulation of proliferation of neoplastic cells, as well as of the immune system, are other actions of ghrelin. Therefore, we consider ghrelin a gastrointestinal peptide contributing to the regulation of diverse functions of the gut-brain axis. So, there is indeed a possibility that ghrelin analogs, acting as either agonists or antagonists, might have clinical impact.  相似文献   

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The genus Nairovirus of arthropod-borne bunyaviruses includes the important emerging human pathogen, Crimean–Congo hemorrhagic fever virus (CCHFV), as well as Nairobi sheep disease virus and many other poorly described viruses isolated from mammals, birds, and ticks. Here, we report genome sequence analysis of six nairoviruses: Thiafora virus (TFAV) that was isolated from a shrew in Senegal; Yogue (YOGV), Kasokero (KKOV), and Gossas (GOSV) viruses isolated from bats in Senegal and Uganda; Issyk-Kul virus (IKV) isolated from bats in Kyrgyzstan; and Keterah virus (KTRV) isolated from ticks infesting a bat in Malaysia. The S, M, and L genome segments of each virus were found to encode proteins corresponding to the nucleoprotein, polyglycoprotein, and polymerase protein of CCHFV. However, as observed in Leopards Hill virus (LPHV) and Erve virus (ERVV), polyglycoproteins encoded in the M segment lack sequences encoding the double-membrane-spanning CCHFV NSm protein. Amino acid sequence identities, complement-fixation tests, and phylogenetic analysis indicated that these viruses cluster into three groups comprising KKOV, YOGV, and LPHV from bats of the suborder Yingochiroptera; KTRV, IKV, and GOSV from bats of the suborder Yangochiroptera; and TFAV and ERVV from shrews (Soricomorpha: Soricidae). This reflects clade-specific host and vector associations that extend across the genus.  相似文献   

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