Rolling in P-selectin-deficient mice is reduced but not eliminated in the dorsal skin

P-selectin-mediated rolling is believed to be important in the recruitment of leukocytes to tissue after ischemia-reperfusion injury. The dorsal skin chamber was used to examine differences in the rolling and stable adhesion of circulating leukocytes in subcutaneous (SC) vessels of P-selectin-deficient and age-matched wild-type mice, both under basal conditions and after ischemia-reperfusion. Rolling in the postcapillary venules in SC tissue of P-selectin-deficient mice was significantly lower than that in wild-type mice under the basal conditions and post-ischemia-reperfusion (P < .05), but was not eliminated by the deletion of the P-selectin gene. No significant difference between P-selectin-deficient and wild-type mice in shear rate or leukocyte-endothelial adhesion was observed up to 24 hours after ischemia-reperfusion. These results show that P-selectin-mediated rolling is not a prerequisite for ischemia-reperfusion-induced leukocyte-endothelial adhesion in the skin.     

Neuroimaging and spectroscopy in children with epileptic encephalopathies

AIMS: To investigate the nature of the unifocal cortical abnormalities on FDG positron emission tomography (PET) in children with an epileptic encephalopathy but no focal abnormality on electroencephalogram or standard magnetic resonance imaging (MRI). METHODS: Repeat FDG PET, surface rendered high resolution MRI, and single voxel magnetic resonance proton spectroscopy of the areas of abnormal metabolism compared to the contralateral side in 11 children aged 2 to 12 years. Imaging was repeated after a median of 13 months. RESULTS: Visual analysis of repeat FDG PET revealed similar abnormalities in 10 of 11 children. Semiquantitative analysis revealed similar sited abnormalities in eight children. One child with ictal hypermetabolism initially had an inconsistent second scan. Magnetic resonance spectra in three children showed the N-acetyl-aspartate/choline ratio was lower in the hypometabolic focus than in the reciprocal area on the opposite side, in two children it was higher, and in one child it was equal. Surface rendered MRI was normal in seven of eight children, and showed temporal lobe asymmetry in one. CONCLUSION: In children with established epileptic encephalopathies most hypometabolic areas on FDG PET are stable over time. While focal neuronal loss is likely in these areas in some children, microdysplasias or other focal cortical dysplasias are probable in others.     

Mycoplasma pneumoniae infection and neurological disease

The cases are reported of 13 children seen over a 22 month period who presented with a variety of acute neurological illnesses associated with Mycoplasma pneumoniae infection. Although presentation with a decreased level of consciousness or seizures was common, psychosis, hemiparesis, cranial nerve palsies, and Guillain-Barré syndrome were also seen. In contrast with published reports, only one child had an associated chest infection. Although some children have been left with residual disability, most have made a complete recovery. In this recent experience, M pneumoniae is a not rare cause of neurological illness in childhood and may present in unusual ways.     

Cutaneous ganglioneuroma within a giant congenital nevus

Cutaneous ganglioneuroma has only occasionally been reported in the literature. Cutaneous ganglioneuroma is seen even more rarely in association with a giant congenital nevus. Differential diagnosis includes malignancies, especially melanoma and metastatic neuroblastoma.It is essential to rule out malignancy in a solid lesion within a congenital nevus. The present report is possibly the first relating ganglioneuroma and a congenital nevus to a cervical mass detected during routine prenatal ultrasound.     

005 2000年国际心肺复苏指南简介

近年来,有关心肺复苏(CPR)基础研究及临床试验领域研究十分活跃,为此美国心脏协会在汇同了各大洲权威复苏委员会意见后,于2000年8月首次拟定并公布了国际心肺复苏指南.本文拟就该新指南中的若干重要进展简介如下. 1 2000年国际CPR指南更注重以科学、循证为据 新指南的重要标志在于,参照大量随机对照试验(RCT)结果,依科学、循证医学为据,对既往指南进行了全面、公正、客观的论证与评价,摒弃了地区和国界的差异,且不拘泥于某学术权威、机构或国家的各自标准,首次由跨国度、洲际的权威机构共同撰写而成,乃是全体专家智慧与实践的结晶. 2 2000年国际CPR指南建议取消检测脉搏有无来判定心脏聚停 新指南的另一重要标志在于删除了复苏前检核脉搏.认为检测脉搏并不可靠.实践证明,对于现场救助者尤其是非医务人员,检测脉搏不仅手法往往不规范,且耗时较久,结果使之不能及时实施CPR和电除颤.此外,据统计,由现场非专业救助者因触及患者脉搏自身的细微自颤,而作出其心脏并未真正停搏的假阴性漏诊率高达10%,终至此类患者在事发现场由于漏诊而丧失或延误了室贵的抢救时间,而不幸生物死亡.故新指南建议,取消现场检测脉搏,认为在决定实施胸外按压前,无需检测脉搏,只需结合患者意识丧失、呼吸停止、以及对咳嗽、触动等刺激的反应来综合判定即可. 3 2000年国际CPR指南更强调现场急救与早期除颤 新指南再次强调,对于心脏骤停者,事发现场应争分夺秒,全力抢救.认为现场急救的成败与生存链(chain of survival)的建立息息相关.该生存链包括早期通路、早期CPR、早期除颤与早期高级生命支持4链环节,亦即在心脏骤停事发现场,均应立即通知医疗部门,同时实施CPR,尽早除颤和高级生命支持.并建议应尽早使用紧急自动体外除颤(AED). 4 2000年国际CPR指南建议简化胸外按压与人工呼吸频度 新指南建议,将CPR时的胸外按压频度由既往的80～100次/min上调至100次/min,调幅达25%;并建议无论单、双人复苏,胸外按压/人工呼吸比均统一为15∶2(原指南中双人复苏按压/呼吸比为5∶1,单人复苏按压/呼吸比15∶2).实践证明,高频按压能获得更有效的前向血流;而按压/呼吸15∶2配合比,既可减少胸外按压中断间期,又能获得更大的胸腔内压;且每次中断胸外按压而行人工呼吸后,均需多次按压才能恢复先前按压所维持的血流,而许多复苏者按压频率往往过低.故新指南减少了每次按压之间的间隔,而增加了每分钟按压频率.从而保证了在等同时间内,既增加前向血流,又提高胸腔内压,且操作更有节律,更简便易行. 5 2000年国际CPR指南建议CPR时实施二阶段ABCD四步复苏 新指南建议,抢救心脏骤停者时,实施CPR可按以下二阶段ABCD四步进行.第1个ABCD四步包括:A开放气道,B正压通气,C胸外按压,D如为室速/室颤则应立即除颤;第2个ABCD四步包括:A进一步气道控制,B评估气管内插管是否充分、正压通气,C建立液路及给药,D鉴别处理一切可逆转病因. 6 2000年国际CPR指南认为CPR时面罩给氧等效于气管内插管给氧 新指南认为,抢救实施CPR时,口对口人工呼吸给氧效果较差.而选择气囊一面罩给氧,较气管插管给氧更简捷且等效,建议在现场及转运途中亦不应中断.据晚近的1项RCT结果证明,气囊一面罩给氧与气管插管给氧一样能有效提高CPR成功率.是否行气管插管最好依据患者情况和救助者经验而定. 7 2000年国际CPR指南建议CPR时的辅助用药 新指南建议,抢救心脏骤停者,如属室速/室颤,可首先连续3次电除颤.对3次除颤仍无效者,选用肾上腺素1mg静注,每3～5min可复行,或/和单剂加压素40U静注,继之再电除颤数次;如为非室速/室颤,建议仅用肾上腺素1mg静注,每3～5min可重复,暂不主张电除颤.对于顽固性室速/室颤,实践证明只有胺碘酮才显示了它有益的治疗前景,而其它传统药物如利多卡因、Bretyhium、普鲁卡因酰胺等的抗室速/室颤作用,均未能得到RCT的证实,且疗效均差. 8 2000年国际CPR指南建议CPR时的液体选择 新指南建议,CPR宜选用生理盐水,不宜再用糖水,因后者可在缺氧条件下代谢成乳酸,而加重酸中毒;且晶体液尚有助于使浓缩的血液稀释,益于循环重建. 9 2000年国际CPR指南中CPR其它相关建议 新指南建议,进一步普及CPR规范抢救方法,建议在各公共场所增设或更新先进的便携式AED仪,尽快建全全球急救网络网站及CPR专门机构. (袁志敏石延华摘)     

Defects in hemostasis in P-selectin-deficient mice

Recently, our laboratory showed that platelets, like leukocytes, roll on activated endothelium expressing P-selectin, thus suggesting a role for P-selectin in hemostasis (Frenette et at, Proc Natl Acad Sci USA 92:7450, 1995). We report here that the P-selectin--deficient mice show a 40% prolongation of the bleeding time on amputation of the tip of the tail. Moreover, defective hemostasis was observed in a local Shwartzman- like reaction induced by skin injections of lipopolysaccharide followed by tumor necrosis factor-alpha in the P-selectin--deficient mice. The hemorrhagic lesions, quantitated both macroscopically and microscopically, were twofold larger in the P-selectin--deficient mice. This was also confirmed by measuring the radioactivity in the skin using chromium-labeled red blood cells. Therefore, it is evident that P- selectin plays a role in hemostasis as suggested by its support of platelet rolling.