心脏移植和心肺移植现状与相关问题的探讨

目前全世界300多个心脏中心进行心脏移植,总例数已超过7万,每年3000多例,30 d手术死亡率5%～10%.2005年国际心肺移植注册协会报告70 201例心脏移植患者,1 a存活率79%,以后每年以4%死亡率递减,最长存活病例已超过30 a.根据国际多中心研究结果显示死亡原因22%为急性心衰,22%为感染,15%为排斥反应,随着移植时间延长冠状动脉病变和恶性肿瘤等也是主要死亡原因.目前我国心脏移植大约300例.心肺移植术开展较心脏移植术晚,手术与术后处理都较心脏移植难度大,目前全世界共开展心肺移植3000例左右,1 a生存率72%.西京医院2000-01/2005-07共开展同种异体原位心脏移植29例,1 a存活率79%,其中2003年后11例术后无手术并发症、排斥反应及死亡.本文结合文献分析和移植经验探讨几个有关问题.     

A ketogenic drink improves brain energy and some measures of cognition in mild cognitive impairment

IntroductionUnlike for glucose, uptake of the brain's main alternative fuel, ketones, remains normal in mild cognitive impairment (MCI). Ketogenic medium chain triglycerides (kMCTs) could improve cognition in MCI by providing the brain with more fuel.MethodsFifty-two subjects with MCI were blindly randomized to 30 g/day of kMCT or matching placebo. Brain ketone and glucose metabolism (quantified by positron emission tomography; primary outcome) and cognitive performance (secondary outcome) were assessed at baseline and 6 months later.ResultsBrain ketone metabolism increased by 230% for subjects on the kMCT (P < .001) whereas brain glucose uptake remained unchanged. Measures of episodic memory, language, executive function, and processing speed improved on the kMCT versus baseline. Increased brain ketone uptake was positively related to several cognitive measures. Seventy-five percent of participants completed the intervention.DiscussionA dose of 30 g/day of kMCT taken for 6 months bypasses a significant part of the brain glucose deficit and improves several cognitive outcomes in MCI.     

呋喃二氢吡啶Ⅰ对离体兔心局部缺血的保护作用

呋喃二氢吡啶Ⅰ20μmol╱L能使离体兔心局部缺血心肌肌酸磷酸激酶(CPK)和α-羟丁酸脱氢酶(HBD)的释放量明显减少;冠脉阻力下降,流量增加;并能降低血浆及心肌中钙、钠含量,预防缺血性心律失常的发生。提示该药对离体兔心缺血心肌的保护作用,与降低缺血心肌细胞钙、钠含量有关。     

BCG vaccination and pulmonary tuberculosis in Quebec

The BCG vaccination program officially set up in 1949 in the Province of Quebec has been retrospectively evaluated for the period from 1956 to 1961. Two series of age groups were studied, 0-14 and 15-29, each comprising populations of several hundred thousand. At the beginning and the end of the period, the rates of primary vaccination were, in percentages of viable births, from 40 to 47.8 and, in cumulative percentages, for the 0 to 14 year age group, from 39.98 to 53.41, and for the 0 to 29 year age group, from 29.22 to 45.98.

During this period, the ratios between the yearly rates of incidence of new cases of pulmonary tuberculosis per 100,000 in vaccinated and non-vaccinated individuals ranged from 1-2.5 to 1-3.5 within the age group 0-14 years and from 1-4.5 to 1-7 within the age group 15-29 years. When only the incidence of the more severe forms of tuberculosis is considered, the ratios ranged from 1-3.7 to 1-6.0 for the younger group and from 1-5.3 to 1-7.6 for the older one.

Mortality from pulmonary tuberculosis was practically non-existent in the vaccinated groups and decreased from 2.5 to 1.3 per 100,000 population in the non-vaccinated groups.

     

Inhibitory action of neuropeptide Y on agonist-induced responses in isolated guinea pig trachea.

The effect of neuropeptide Y (NPY) was tested on isolated guinea pig trachea. At 30 nM, NPY induced a weak but significant contractile response which was on average less than 6% of responses elicited by standard spasmogens. This myotropic action of NPY was blocked by indomethacin. In addition to its contractile activity, NPY greatly reduced the maximal response to vasoactive intestinal peptide (VIP), noradrenaline (NA), substance P (SP) and 5-hydroxytryptamine (5-HT), without affecting their pD2 values. However, NPY did not influence the response induced by histamine and carbamylcholine. Pretreatment of tracheal spirals with indomethacin (10(-6) M) abolished the NPY-evoked inhibition of VIP, SP and 5-HT responses but failed to reduce the action of NPY on NA-elicited relaxation. This latter effect was however blocked in the presence of tetrodotoxin. In conclusion, NPY inhibits responses elicited by various agonists in the guinea pig trachea. This effect seems to be mediated at both pre- and postjunctional levels. The postjunctionally mediated inhibitory action of NPY appears to be expressed especially with agents that generate prostaglandins concomitantly with inducing their response. In contrast, the NPY-evoked inhibition of NA-evoked relaxation seems to be mediated via a prejunctional mechanism.     

尼可地尔对缺血再灌注心肌线粒体功能的保护作用

近年来,许多资料表明,心肌缺血再灌注损伤与氧自由基有关,后者的主要细胞毒性反应是膜的脂质过氧化。尼可地尔(nicorandil,NICO)又名N-(2-羟乙基)硝酸烟酰胺,为烟酰胺与硝酸酯的结合物,是临床治疗心绞痛的新药。前文发现它对心肌缺血再灌注损伤有保护作用,其作用可能与抗脂质过氧化有关。本文用血液灌注离体兔心模型,观察缺血再灌注损伤时心肌线粒体呼吸功能的变化,及尼可地尔的保护作用。