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排序方式: 共有357条查询结果,搜索用时 15 毫秒
31.
Melatonin receptor expression in the cornea and sclera 总被引:3,自引:0,他引:3
The scornea and sclera have been shown to exhibit circadian rhythms in cellular proliferation, wound healing and extracellular matrix synthesis. The distribution of melatonin Mel1a and Mel1c receptors was examined in the cornea and sclera of the Xenopus laevis eye in order to determine whether melatonin may potentially influence the growth and/or development of these ocular tissues. Sections of adult X. laevis eyes were analyzed by immunocytochemistry and confocal microscopy, using antibodies prepared against specific peptide sequences of the Xenopus Mel1a and Mel1c receptor proteins. Antibodies were pre- incubated with their appropriate antigenic peptides to control for non-specific labelling. Analysis of the distribution of Mel1a and Mel1c receptor immunoreactivity in the Xenopus eye revealed that both the Mel1a and Mel1c receptors were located in the outer fibrous layer (OFL) of the sclera, with Mel1c labelling being the most prominent. Similarly, Mel1a and Mel1c (Mel1c mostly) were also located in cells of the inner fibrous layer (IFL) with Mel1c being most abundant. The chondrocytes of the cartilaginous layer also appeared to express Mel1a, Mel1c, or both receptors. Both Mel1a and Mel1c receptor immunoreactivity were observed in the corneal epithelium and endothelium. Whereas the Mel1a antibody labelled the entire corneal epithelial layer, the Mel1c antibody labelled only the most superficial layer of epithelial cells. Cell processes of fibroblasts of the corneal stroma were immunoreactive for either Mel1a or Mel1c receptors. The identification of Mel1a and Mel1c receptors in restricted distributions in the cornea and sclera suggests that melatonin may play a role in the cellular physiology of these ocular tissues. 相似文献
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Dani C Bertini G Reali MF Tronchin M Wiechmann L Martelli E Rubaltelli FF 《Biology of the neonate》2000,78(1):27-32
OBJECTIVE: To investigate the acute effects of low-dose caffeine and aminophylline on cerebral blood flow in preterm infants, using both near-infrared spectroscopy (NIRS) and cerebral Doppler ultrasonography. METHODS: Preterm infants with a gestational age of <32 weeks and birth weight of <1,500 g were randomized to receive either caffeine or aminophylline treatment for apnea of prematurity. The study period went from 30 min before to 60 min after the administration of the maintenance dose of pure caffeine (2.5 mg/kg once a day) or aminophylline (1.25 mg/kg twice a day). NIRS was used to measure changes in oxygenated hemoglobin (O(2)Hb), deoxygenated hemoglobin (HHb), oxidized-reduced cytochrome aa3 (CtOx), and mean cerebral oxygen saturation (SmO(2) = O(2)Hb/total Hb). Changes in cerebral blood volume (DeltaCBV) after caffeine or aminophylline administration were calculated. Cerebral blood flow velocity (CBV) in the pericallosal artery was evaluated by cerebral Doppler ultrasounds. RESULTS: Data collected by NIRS and cerebral Doppler ultrasounds did not show significant differences before and after caffeine treatment. We observed a significant increase in O(2)Hb and HHb concentration and in CBV at 30 min after the infusion of aminophylline, which tended to return to baseline at the end of the study period. CONCLUSION: Caffeine does not significantly affect brain hemodynamics, while aminophylline induces a significant transient increase in O(2)Hb and HHb concentration and CBV. 相似文献
33.
Results of randomized controlled trials of low-versus high-osmolality contrast media 总被引:1,自引:0,他引:1
The authors reviewed 100 randomized controlled trials (RCTs) conducted in humans to compare safety or efficacy of new low-osmolality contrast media (LOM) with that of high-osmolality contrast media (HOM). Findings of the 43 RCTs judged to be of the highest quality suggest that the efficacy of LOM in imaging is equal or superior to that of HOM for all routes of administration. Heat sensation occurred less often with LOM for all routes and pain occurred less often with LOM for intraarterial routes. No differences were seen in nephrotoxicity or in frequency of nausea, vomiting, urticaria, bronchospasm, laboratory test abnormalities, or neurologic events. Greater cardiovascular changes were seen with HOM, including increased or decreased heart rate, increased left ventricular end-diastolic pressure, decreased systolic pressure, and QT prolongation, depending on route of administration. To demonstrate whether a reduction in clinically significant adverse outcomes truly occurs with LOM, trials will need to enlist larger numbers of patients and employ appropriate outcome measures. Future trials should stratify patients according to their risk of adverse reactions to provide better information about benefits of LOM in low- versus high-risk patients. 相似文献
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Ernst Wiechmann 《Journal of molecular medicine (Berlin, Germany)》1923,2(13):601-604
Ohne Zusammenfassung 相似文献
36.
Flexible tantalum stents implanted in aortas and iliac arteries: effects in normal canines 总被引:2,自引:0,他引:2
Barth KH; Virmani R; Strecker EP; Savin MA; Lindisch D; Matsumoto AH; Teitelbaum GP 《Radiology》1990,175(1):91-96
Vascular endoprostheses made of knitted tantalum wire and expanded over angioplasty balloons were placed into aortas or iliac arteries of 14 normal dogs. Twelve stents were placed into the infrarenal abdominal aorta and two stents in the left common iliac arteries by the left carotid artery approach. To firmly expand the stent against the vascular wall, nominal stent sizes 0.5-1.0 mm larger than the measured arterial diameter were required. Arteriography performed at specified follow-up intervals showed no evidence of thrombi or emboli; all side branches (lumbar arteries) covered by the stents remained patent. Vascular diameter decreased minimally at 8 and 26 weeks, associated with histopathologic evidence of neointimal buildup. This buildup was highest at 8 weeks (mean, 313 microns) and was slightly less at 26 weeks (mean, 223 microns). Almost complete coverage by endothelium was seen as early as 3 weeks. It is concluded that the flexible tantalum wire stents are well tolerated by the arterial wall and become quickly endothelialized. No excessive neointimal buildup was observed during the 6-month study. 相似文献
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Ernst Wiechmann 《Clinical and experimental medicine》1925,44(1):328-354
Ohne Zusammenfassung
Die Arbeit wurde mit Unterstützung der Rockefeller Foundation ausgeführt. 相似文献
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