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1.
Reactive oxygen species and human spermatozoa: physiology and pathology 总被引:20,自引:1,他引:19
The role of reactive oxygen species (ROS) in the pathophysiology of human sperm function has been emphasized in recent years. ROS production in semen has been associated with loss of sperm motility, decreased capacity for sperm–oocyte fusion and loss of fertility. There is a current presumption that the most prolific source of ROS in sperm suspensions is an NADPH oxidase located in leukocytes or in spermatozoa which produces superoxide which is further converted to peroxide by the action of superoxide dismutase. Hydrogen peroxide has been recognized as the most toxic oxidizing species for human spermatozoa, which are very sensitive to lipid peroxidation owing to the high content of polyunsaturated fatty acids in their plasma membrane, though this is not the sole mechanism by which sperm function might be impaired by ROS. Although the excessive production of ROS is detrimental to human spermatozoa, there is a growing body of evidence which suggests that ROS are also involved in the physiological control of some sperm functions. This review focuses on the nature and source of the ROS generated by human spermataozoa as well as their operational mechanisms and their effects, which may be detrimental or beneficial. 相似文献
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M Ia Ratner M A Brodski? M L Zubkin I I Stenina I M Slutskin 《Terapevticheski? arkhiv》1991,63(6):12-15
Tubulointerstitial alterations associated with chronic glomerulonephritis (CGN) are definitely dependent on the clinical type of CGN and are accompanied by a decrease of homeostatic functions (the rate of glomerular filtration, osmotic concentration and dilution of urine, hydruresis, the magnitude of CH2O, excretion of ammonium and hydrogen ions, the ratio of ammonium excretion to hydrogen ion excretion). Maximal osmotic concentration and ammonium excretion show an especially considerable decrease. The clinical type permitting one to diagnose rather than to reject the presence of alterations and the status of certain tubular functions, osmotic concentration in particular and, to a less degree, ammonium excretion, permitting to reject the presence of the tubulointerstitial component (TIC) are of known but restricted importance for TIC recognition. The TIC can be diagnosed more adequately in exploring definite pairs of renal functions, particularly osmotic concentration of urine and ammonium excretion and maximal hydruresis and excretion of hydrogen ions. This approach is both helpful in confirming and rejecting the presence of the TIC. Of special value is the combined assessment of the clinical type and maximal osmotic urine concentration data. 相似文献
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研究不同微生物诱导家蝇幼虫表达的抗菌肽特性.用3种不同的病源菌通过针刺感染的方法诱导家蝇幼虫表达抗菌肽,通过Sephadex G25分离,用Hult mark改进法和抑菌圈测定法作抑菌试验,用毛细管电泳(CE)分析不同微生物诱导得到的抗菌肽样品差异,检测抗菌肽的热稳定性和酸碱耐受性.发现不同微生物诱导产生的家蝇抗菌肽具有广谱抑菌性,但不同样品对不同病源菌抑菌活性有差异,不同测定抑菌效果的方法对抑菌结果有影响,各种抗菌肽样品CE蛋白谱具有明显不同.抗菌肽样品都具有热稳定性和酸碱耐受性.说明不同微生物诱导产生的家蝇抗菌肽类型以及抗菌肽含量与诱导源有关,抗菌肽为家蝇幼虫体内固有成分,诱导增加了抗菌肽的表达量同时刺激新抗菌肽的产生.用志贺氏菌、金黄色葡萄球菌、鼠伤寒沙门氏菌诱导家蝇幼虫可产生较多含量高活性好的抗菌肽. 相似文献
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Francine Ratner Kaufman Mary Halvorson Neal D. Kaufman 《Diabetes research and clinical practice》1995,30(3):205-209
Objective: To determine if uncooked cornstarch, as part of the evening snack, can avert nocturnal hypoglycemia in type 1 diabetes. Research Design and Methods: Fifty-one campers and counselors at the American Diabetes Association Camp in San Bernardino, CA were randomly assigned to receive 5 g of uncooked cornstarch as part of the 21:00 evening snack vs. a standard snack of equivalent carbohydrate content. Each snack was given for five nights and the participants and medical personnel were blinded as to assignment. Midnight and 07:00 finger stick blood glucose levels were compared with values <60 mg/dl defined as hypoglycemia and values >250 mg/dl defined as hyperglycemia. Results: There were 218 midnight and 222 07:00 values for comparison. There were six episodes of hypoglycemia at midnight and nine episodes of hypoglycemia at 07:00 for the cornstarch snack nights vs. 30 hypoglycemia episodes at midnight and 21 at 07:00 for the standard snack nights (P < 0.001 and < 0.05, respectively). There was no difference in the number of hyperglycemic events at midnight or 07:00 for the cornstarch vs. standard snack nights. At midnight, 12% of campers had hypoglycemia after the cornstarch snack vs. 46% after the standard snack (P < 0.001), and at 07:00, 16% had hypoglycemia after cornstarch vs. 26% after the standard snack (P = 0.327). Conclusions: These data suggest that uncooked cornstarch, as part of the evening snack, can diminish the nighttime and morning hypoglycemia associated with type 1 diabetes, without causing hyperglycemia. 相似文献
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The federal Medicare Diagnostic Related Group (DRG) hospital reimbursement system has been on line for 5 years. Hospitals contend that profit margins have dropped to dangerously low levels, due to the federal DRG Prospective Payment System. The authors analyzed all orthopedic surgical admissions to a large academic medical center under DRG reimbursement and characterized patients by age, resource utilization, and outcome. Total costs for the 1,040 orthopedic patients analyzed during a 15-month period added up to $9,718,800. Mean hospital cost per patient, mean hospital length of stay, percent outliers, and mortality generally increased with age. All age categories of patients 65 years of age and above generated financial losses under DRGs. Older orthopedic patients consumed a disproportionately larger share of resources than younger patients, and were more frequent users of the SICU and blood. The current DRG reimbursement scheme may be inequitable in relation to the older orthopedic surgery patient. If these findings are demonstrated at other medical centers, older orthopedic surgical patients could be limited in both their access and quality of care in the future. 相似文献