两种不同方法测定低水平压力支持通气时气道阻断压与自主呼吸时常规方法测定值的相关性分析

目的 拟比较以两种不同方法测定低水平压力支持通气（pressure support ventilation，PSV）病人的气道阻断压（P0．1）与自主呼吸时常规方法测定值的相关性。方法 12例机械通气病人，断开呼吸机自主呼吸时以常规方法测定P0．1得到P0．1-SB：在PSV水平为5cmH20，以常规方法和按压呼气末暂停键测定P0．1分别得到P0．1-PSV5和P0．1-PSV5eeo．分析后二者与前者之间的相关性。结果 P0．1-SB与P0．1-PSV5之间差异无显著性，P0．1-PSV5ee0分别小于P0．1-SB与P0．1-PSV5，差异有显著性；P0．1-PSV5eeo与P0．1-PSV5和P0．1-SB之间的相关系数均为0．97。结论 按压呼气末暂停键测定PSV水平为5cmH2O的P0．1值与常规方法测定的PSV水平为5cmH2O以及自主呼吸时的测定值相比，其值偏小,但前者与后二者之间具有良好的相关性。     

Ocular findings in familial adenomatous polyposis

Background: Retinal pigment epithelium (RPE)lesions are predictive congenital phenotypic markersfor familial adenomatous polyposis (FAP). Thisprospective screening study aims at assessing theincidence and significance of these lesions in FAPpatients and their family members.Methods: Sixty-two members from three familiesincluding five patients with the diagnosis of FAP havebeen ophthalmologically surveyed. All RPE lesions weredocumented with fundus photography and fluoresceinangiography was performed in 13 subjects.Sigmoidoscopy and/or radiological examination wereperformed annually in 9 family members with typicalRPE lesions during 4 years to allow early diagnosis ofFAP.Results: Typical RPE lesions were present infive FAP patients and 15 family members.Telangiectatic dilatations in the retinal peripherywith small dot-like hemorrhages were detected in 6subjects from 3 families These lesions wereparticularly evident on fluorescein angiography.Annual colon analysis showed polyps in 3 out of 9subjects who were positive for RPE lesions.Conclusion: RPE lesions are valuable as aclinical marker in predicting FAP. The co-existingperipheral vascular alterations which have not beenreported before, are probably related to FAP.     

Development of neurochemical separation of ON and OFF channels at retinal ganglion cells

Anatomical and physiological segregation of neurons into ON (brightening detector) and OFF (darkening detector) channels in the retina and subsequent visual system ensure the high sensitivity required for contrast detection and spatial discrimination. This segregation is finest at the visual axis. Neurochemically, ON and OFF ganglion cells at the visual axis seem to be distinguished by different inhibitory transmitters but not excitatory transmitters. Microiontophoretic studies of inhibitory transmitters on the retinal ganglion cells in kittens and adult cats suggest that this neurochemical distinction is poor in immature ganglion cells at the visual axis. Initially both ON and OFF cells seem to be supplied by GABAergic, glycinergic, and catecholaminergic amacrine cells, but in adults, ON cells remain supplied only by GABAergic amacrines, while OFF cells are supplied by glycinergic amacrines. Postnatal elimination of multiple inputs and strengthening of the appropriate inputs, as seen in the central nervous system, also seem to occur at the retinal neurotransmitter synapses during development.     

Matrix Metalloproteinase-2 and Tissue Inhibitor of Metalloproteinase-1 in the Retinal Pigment Epithelium and Interphotoreceptor Matrix: Vectorial Secretion and Regulation

Matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) play an essential role in both normal and pathological extracellular matrix degradation, and a TIMP has been associated with at least one type of retinal degeneration. We have studied expression of MMP-2 and TIMP-1 by zymography, immunocytochemistry, and immunoblotting in the retinal pigment epithelium (RPE) from normal, aged and diseased retinas. MMPs and TIMPs were found in the rat RPE, interphotoreceptor matrix (IPM), and in media conditioned by human and rat RPE in culture. In other polarized cells, MMPs and TIMP-2 are secreted vectorially towards the basal lamina. In the RPE, however, MMP-2 and TIMP-1 were secreted preferentially from the apical surface, the surface bordering the IPM. These findings provide new evidence that MMPs and TIMPs could play a role in the turnover of IPM components.Cell homogenates and conditioned media from RPE isolated from mutant Royal College of Surgeons (RCS) rats with inherited retinal dystrophy had similar amounts of MMP-2 and TIMP-1 as those from congenic control rats. The secretion of MMP-2 and TIMP-1 from RPE cell cultures isolated from young and aged human donors varied widely. However, with increasing cell passage number, secretion of MMPs and TIMPs from human RPE increased dramatically. Also, growing human RPE on bovine corneal endothelial cell-generated extracellular matrix instead of plastic reduced the secretion of both MMPs and TIMPs. These data suggest that the integrity of Bruch's membrane may serve to regulate RPE functions in MMP and TIMP secretion and that extracellular matrices contain signals that regulate MMP and TIMP synthesis and/or secretion by the RPE.     

Rare diseases mimicking acute vertebrobasilar artery thrombosis

Acute ischaemia of the vertebrobasilar circulation leads to a variety of clinical manifestation and is mostly due to cardiogenic or artery-to-artery embolism. We describe four neurological emergency situations involving vertebrobasilar artery aclusion of other origins: basilar migraine, extrinsic compression by rheumatoid inflammatory tissue, generalized vasculitis in subacute rheumatic fever and basilar artery dissection. The differential diagnosis of acute vertebrobasilar artery occlusion may have an important impact on patient management.     

老年人视网膜中央血管在前部视神经的解剖特征

目的：观察老年人前部视神经视网膜中央血管的解剖特征。 方法：通过组织连续切片和计算机影像分析，观察60~82岁老年人的18只眼球标本中无解剖变异的视网膜中央动脉(CRA)15条，视网膜中央静脉（CRV）23条在筛板前、筛板区及筛板后的管径变化。 结果：老年人筛板前、筛板区、筛板后CRA平均面积的均值分别为（12.70,17.40,18.00）×10^-3mm^2_;平均周长的均值分别为0.56，0.56，0.57mm，平均周长之间相比无显著差异。CRV平均面积的均值分别为（7.00，5.40，7.90）×10^-3mm²；平均周长的均值分别为0.44，0.38，0.41mm；CRV平均周长筛板前与筛板区相比，筛板区与筛板后相比均有显著差异。 结论：老年人CRA眼球内外管径一致；CRV在筛板区管径最小。 （中华眼底病杂志，1997，13：213-214）
     

Research review: DNA polymerases as molecular markers of the regenerating capacity of hepatocytes

Hepatocyte regeneration has been widely investigated, with the mitotic index and the incorporation of [³H]thymidine being used as regeneration markers. We focused on the induction of DNA replication enzymes, particularly DNA polymerases (pol) α, δ, and ε. Using rat models, we have shown that the activity of pol α in crude liver extract well represents the regenerating capacity of hepatocytes. Using pol α as an indicator, we analyzed liver regeneration in rat models under various conditions: obstructive jaundice, external or internal biliary drainage, and the obstruction of portal vein branches. It has been revealed that the ligation of the common bile duct alone induces a certain amount of hepatocyte proliferation. It was striking that external biliary drainage suppressed regeneration capacity in cholestatic rat liver after partial hepatectomy. The strong regeneration in nonligated lobes induced by portal branch ligation was similar to the liver regeneration seen after partial hepatectomy with respect to the induction of DNA polymerases. Taken together, the aspects of DNA replication, particularly the induction of DNA polymerases, may contribute to shedding new light on the regeneration of human liver. This work was supported in part by a Grant-in-Aid for General Scientific Research and for Cancer Research from the Ministry of Education, Science and Culture, Japan, and by grants from the Uehara Memorial Foundation     

血液与非血液灌流行缺血预处理鼠心的电生理实验研究

本实验研究血液与非血液灌流条件下缺血预处理（ＩＰ）对心肌的保护作用。应用离体大鼠Ｌａｎｇｅｎｄｏｒｆ灌流模型，分血液灌流ＩＰ组、非血液（ＫｒｅｂｓＨｅｎｓｅｌｅｉｔ液，ＫＨ液）灌流ＩＰ组及相应的对照组。测量心肌电生理特性等指标。结果与ＫＨ液灌流心脏相似，用血液灌流的大鼠心脏经ＩＰ后，在随后的停灌和复灌期间，心室颤动阈升高，心律失常发生率明显降低。实验结论为在用血液灌流离体大鼠心脏模型上，ＩＰ对心肌的保护作用与用生理溶液灌流的模型基本相同。     

带血管蒂舟骨瓣移位术的应用解剖

目的:为治疗距骨骨折提供新术式的解剖学基础.方法:在30侧灌注红色乳胶的成人下肢标本上,对舟骨背侧面形态、血供来源进行观测.结果:舟骨背侧面动脉主要来自内踝前动脉、跗内侧动脉以及足底内侧动脉浅支,分别发3～5支、1～3支和1～2支外径在0.2～1.0mm之间的骨膜支,形成骨膜动脉网.结论:以内踝前血管为蒂,可切取舟骨背侧2.0cm×1.0cm×0.5cm大小的骨瓣,用于距骨颈骨折修复.术式经临床应用证实,手术简便,效果可靠.     

Effects of intravenous L-acetylcarnitine on retinal oscillatory potentials

L-acetylcarnitine is a compound with cholinergic properties and putative action on the visual system and the glucose metabolism. Ten healthy, emmertropic volunteers (age range: 21 to 28 years) were studied. Each subject was administered 5, 10, and 30 mg/kg acute intravenous doses of L-acetylcarnitine and matching placebo. Retinal oscillatory potentials to full-field flash stimulation were recorded before and 30, 60, and 120 min after administration. A systematic reduction of the implicit time of the P2 and N2 oscillatory potential components was observed after administration of the 10 and 30 mg/kg doses: significant changes were not evident at the 5 mg dose or after placebo. The latency reduction was significantly correlated with the postdrug increment of the L-acetylcarnitine plasma concentration. No other systematic modification in latency of amplitude was observed.The results were presented in part at the XXV I.S.C.E.V. Symposium, Sarasota (Florida), April 26–30, 1987.