脐带血和成人外周血TCR Vγ和Vδ亚家族的分布和克隆性研究

目的探讨脐带血和健康成人外周血TCR Vγ和Vδ基因谱系的分布情况及克隆性特点。方法利用RT-PCR法检测16例脐带血和10例健康成人外周血单个核细胞TCRVγ(Ⅰ～Ⅲ)和Vδ(1～8)各亚家族的表达,了解各亚家族的分布和利用情况;阳性的PCR产物进一步经荧光素标记和基因扫描分析其CDR3长度,了解T细胞的克隆性。2例成人胸腺组织作为对照。结果脐带血T细胞的Vγ基因表达主要集中在VγⅠ和VγⅡ,而Vδ基因则平均表达(4.63±1.03)个亚家族,主要集中在Vδ1、2、3、8中表达。健康成人外周血T细胞除了1例不表达VγⅢ之外,其余均表达全部Vγ基因,而在Vδ基因中则平均表达(3.6±0.52)个亚家族,并以Vδ1、2和3为多见,Vδ4和Vδ5未能在外周血中检测到,而Vδ5和Vδ8的表达则明显低于脐带血(P=0.009,P=0.001);2例成人胸腺组织表达除Vδ4和Vδ6之外的其他Vγ和Vδ亚家族。基因扫描显示16例脐带血中有1例在VγⅠ和5例分别在Vδ2、Vδ4和Vδ6中出现寡克隆性,10例成人外周血中有9例在不同亚家族中出现克隆性T细胞,其余均呈多克隆性。结论脐带血TCRVγ和Vδ亚家族T细胞和健康成人外...     

卡介苗多糖核酸对过敏性支气管哮喘外周血单个核细胞TH1/TH2反应的作用

目的观察卡介苗多糖核酸(BCG-PSN)对支气管哮喘患者外周血淋巴细胞TH1/TH2反应的作用,并与结核菌素纯蛋白衍生物(TB-PPD)进行比较. 方法缓解期过敏性支气管哮喘患者16例,对照组健康成人13例,分离外周血单个核细胞(PBMC),分别加入不同浓度的BCG-PSN(1、10、100、1000 μg/ml)、TB-PPD(10 μg/ml)、尘螨抗原(DerP, 10 μg/ml)体外培养4 d,不加刺激剂者为阴性对照.收集培养上清,ELISA检测IFN-γ、IL-5浓度的变化. 结果 PSN(1～100 μg/ml)刺激正常人PBMC分泌IFN-γ水平均高于哮喘患者(P＜0.05).BCG-PSN(10 μg/ml)可以刺激哮喘患者PBMC分泌IFN-γ(358.7 pg/ml,范围0～2433.0 pg/ml),但显著低于同等浓度的TB-PPD刺激作用(13 036 pg/ml,范围600.5～35 100.0 pg/ml,P＜0.01).PSN刺激PBMC分泌IFN-γ呈浓度依赖性,当浓度达到100 μg/ml时,与低浓度相比刺激作用显著增强(P＜0.01),与TB-PPD的刺激作用类似.DerP刺激哮喘患者PBMC分泌IL-5水平显著高于正常人(P＜0.05).BCG-PSN刺激PBMC分泌IL-5的作用较弱,显著低于TB-PPD和DerP的刺激作用. 结论 BCG-PSN具有一定的TH1刺激作用,但低于TB-PPD的刺激作用,有待对BCG-PSN组分进一步优化以增强疗效.     

Different ion channel mechanisms between low concentrations of capsaicin and high concentrations of capsaicin and nicotine regarding peptide release from pulmonary afferents

Vagal nerve stimulation (1 Hz for 1 min), capsaicin (10^-8 M and 10^-6 M), resiniferatoxin (3 × 10^-10 M) and nicotine (10^-4 M) evoked a non-cholinergic bronchoconstriction in the isolated perfused guinea-pig lung preparation. Simultaneously there was an increase in the perfusate levels of calcitonin gene-related peptide-like immunoreactivity, suggesting release from sensory nerves. Both the bronchoconstriction and peptide release evoked by a low concentration of capsaicin (10^-8 M) and that evoked by nerve stimulation were depressed by tetrodotoxin, suggesting involvement of Na⁺ channel dependent depolarization. Since the effects of capsaicin (10^-8 M) and vagal nerve stimulation were inhibited by ω-conotoxin but not influenced by nifedipine, the Ca²⁺-channel involved is probably of N-type. Furthermore, the capsaicin analogue resiniferatoxin also evoked ω-conotoxin sensitive peptide release and bronchoconstriction. At the higher capsaicin concentration (10^-6 M), the functional response was only slightly inhibited by wconotoxin or tetrodotoxin indicating that capsaicin at this concentration evoked peptide release and functional effects through other mechanisms, probably involving Ca²⁺ fluxes in the non-selective cation channel associated with the proposed capsaicin receptor. The nicotine (10^-4 M) evoked peptide release and bronchoconstriction were only marginally influenced by ω-conotoxin or tetrodotoxin. It is concluded that the ion-channel mechanisms underlying the peptide releasing properties of antidromic nerve stimulation and low concentrations of capsaicin are similar and depend on action potential propagation, whereas capsaicin in high, toxic concentration and nicotine mainly act via receptor operated channels.     

Pseudorandom testing technique for the characterization of local hemodynamic control

Summary In order to investigate the low frequency properties of renal and femoral hemodynamic variables, pseudorandom testing techniques were used. The arterial flow of each bed, in separate experiments, was modulated by a low amplitude signal based on a pseudorandom binary sequence (PRBS) generated by digital computer.The cross-correlation functions between input flow and arterial pressure, venous pressure, and venous flow exhibit damped oscillations in all cases. These responses are parameterized in terms of a damping ratio () and an undamped natural frequency _n for a second order model. The parameters of the model are dependent upon the state of the bed as defined by mean arterial and venous pressures, mean flow through the bed, resistance, and oxygen consumption.The results of this study offer further insight into the dynamic low frequency autoregulation phenomenon for the renal and femoral beds of the dog.Supported by NIH Grant HE 11747.     

Recommendations for the examination of peripheral nerve biopsies

 Peripheral nerve biopsy is now an established, valuable investigative procedure, but as it can give rise to significant residual symptoms it should only be undertaken after careful consideration of the indications and with informed consent from the patient. Nerve biopsies should only be processed and evaluated in a laboratory with the relevant particular expertise. It is generally recommended that a sural nerve biopsy be performed in combination with a muscle biopsy but not vice versa (muscle biopsies together with a nerve biopsy). Nerve biopsy is not the only means of sampling peripheral nerve tissue to study the peripheral nervous system. Examination of the innervation of the skin may be informative. The same is likely to be true for motor point muscle biopsy. Nerve biopsy is mainly used for morphology although molecular genetic techniques using fresh or archival nerve biopsies are increasingly available. Chemical analysis is undertaken mainly for research purposes. Received: 10 June 1997 / Accepted: 29 October 1997     

Neurogenic polyps

A neoplastic proliferation of peripheral nerve sheath cells (Schwann cells, fibroblasts and perineurial cells) and ganglion cells in the colorectum may give rise to the mucosal or submucosal polyps. Depending upon the predominant cell types, these neurogenic polyps can be classified as schwannomas, granular cell tumours, neurofibromas, perineuriomas, mixed nerve sheath tumours, ganglioneuromas or paragangliomas. Morphologically, the neoplastic cells repeat or mimic the corresponding nerve sheath cells or neurons in terms of growth pattern, histology and immunoreactivity. They are uncommon, but the polyps can occur in any age group, although the vast majority of patients are adults. The polyps can be either solitary (most peripheral nerve sheath tumours) or multiple, especially if associated with systemic diseases (i.e. syndromes involving the peripheral nerve tissue). They are usually incidental findings or may be accompanied by gastrointestinal symptoms. Almost all colorectal neurogenic polyps are benign, and they rarely undergo malignant transformation unless they are part of a syndromatic manifestation. However, these polyps may cause a diagnostic problem during screening for colorectal cancer. An accurate diagnosis of these entities will help clinicians to make appropriate management decisions.     

横向电场作用下外周神经兴奋特性的实验研究

传统的外周神经电缆方程只能描述纵向电场刺激下外周神经兴奋,实验发现在脉冲磁场诱导的横向电场作用下也可使神经兴奋,从而揭示出需要进一步对感应电场兴奋外周神经的机理进行研究。本文研究了横向电场作用下外周神经的兴奋特性,以在体的人体正中神经为例研究了横向电场作用下外周神经兴奋点的位置、刺激阈值、及刺激阈值与纤维半径的关系,以离体的蟾蜍坐骨神经为例研究了刺激阈值与作用时间的关系。实验结果验证了改进的电缆方程的有效性。实验研究成果有助于磁刺激技术的进一步发展与应用。     

Acid-induced increase in duodenal mucosal alkaline secretion in the rat involves the L-arginine/NO pathway

Duodenal mucosal alkaline secretion increases in response to hydrochloric acid exposure. The tentative role of nitric oxide (NO) in the mediation of this response was investigated. The mucosal alkaline output by a duodenal segment was recorded by in situ titration in chloralose-anaesthetized rats. In some experiments the duodenal blood flow was estimated by laser-Doppler flowmetry. Exposure of the duodenum to acid (0.01 M HCl, 5 min) increased the alkaline secretion by ≈85%. The NO synthase inhibitor N^G-nitro-L -arginine methyl ester (L -NAME, 10 mg kg^?1 intravenously or 0.3 mM intraluminally) blocked the secretory increment after mucosal acid exposure. Mean arterial pressure and basal alkaline secretion were markedly raised, whereas duodenal blood flow was decreased, when L -NAME was given intravenously (i.v.). Intraluminal (i.l.) administration left mean arterial pressure as well as duodenal blood flow unaltered, and the duodenal mucosal alkaline secretion was only slightly elevated. The stereoisomer N^G-nitro-D -arginine methyl ester (D -NAME) had no effect on either basal or acid-induced duodenal alkaline output. In animals receiving L -arginine (10 mg kg^?1 min^?1 i.v., or 3 mM i.l.) and L -NAME, the acid exposure elicited an increase in duodenal mucosal alkaline secretion, similar to that observed in controls. The results suggest that the acid-induced increase in duodenal mucosal alkaline secretion involves NO synthesis, which takes place close to the lumen, probably within the mucosa.     

Vergleichende Untersuchung von niedermolekularem Dextranoder Hydroxyäthylstärkelösungen als Volumenersatzmittel bei Hämodilutionstherapie

Summary Rheological therapy, as an immediate treatment in conjunction with physical therapy and the removal of risc factors, plays a significant role in the management of patients with peripheral vascular disease experiencing reduced walking tolerance. An essential element of rheological therapy is hemodilution. Currently, is still uncertain which plasma substitute solution would be the most appropriate in such cases. This study compared the effectiveness of low molecular hydroxyethyl starch to low molecular dextran during a 16-day hemodilution in combination to physical therapy. The clinical improvement observed with both plasma substitute solutions was comparable, yet in view of the cardiac volume overload, dextran demonstrates greater circulatory stress due to the transient pressure increase and more side effects. For this reason, we prefer to administer low or middle molecular hydroxyethyl starch in the dilution treatment of peripheral arterial occlusive disease as a chronic degenerative vascular disease.

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Abkürzungen A2M Alpha-2-Makroglobulin - D0 Meßzeitpunkt 0 der später mit Dextran behandelten Gruppe - D1 Meßzeitpunkt 1 der Dextran-Gruppe - D2 Meßzeitpunkt 2 der Dextran-Gruppe - Dextran 40 kleinmolekulares Dextran (mittleres Molekulargewicht 40000 Dalton) - ETA Plasmaviskosität - Fib Fibrinogen - Geh Gehstrecke - H0 Meßzeitpunkt 0 der später mit Hydroxyäthylstärke behandelten Gruppe - H1 Meßzeitpunkt 1 der HAES-Gruppe - H2 Meßzeitpunkt 2 der HAES-Gruppe - HAES 40 kleinmolekulare Hydroxyäthylstärke (mittleres Molekulargewicht 40000 Dalton) - Hkt Hämatokrit - LZ Leukozyten-Zahl - Pro Gesamteiweiß - SEA Erythrozyten-Aggregationsindex - SER Erythrozyten-Rigiditätsindex - TY Fließschubspannung - TZ Thrombozyten-Zahl     

The reflex effect of changes in renal perfusion on hindlimb vascular resistance in anaesthetized rabbits

This study was designed to characterise the response of the hindlimb vasculature to reduced renal perfusion in the anaesthetized rabbit and to elucidate whether the stimulus was dependent upon reduced renal perfusion pressure (RPP) or blood flow (RBF). Acute decreases in renal perfusion resulted in rapid and reversible increases in femoral perfusion (FPP). This vascular response was completely abolished following renal denervation indicating that the afferent component of the reflex is neurally mediated. Acute hindlimb responses to changes in renal perfusion pressure were present whether the limb was perfused with homologous blood or cross-perfused with blood from a donor rabbit, demonstrating that the efferent component of the response is also neurally mediated. There was a 28-s latency for initiation of the hindlimb vasoconstriction, which is consistent with recent evidence for renal autocoid stimulation of the afferent renal nerve receptors. Decreasing RPP indirectly, by altering flow, resulted in a hindlimb vasoconstriction below approximately 55 mm Hg (7.3 kPa) RPP or 15 ml/ min RBF. However, decreasing RPP by directly reducing pressure in graded steps resulted in increases in FPP, which reflected the changes in renal flow; thus during the autoregulatory phase, where flow did not change as pressure fell, FPP also remained stable. The results of these protocols suggest that a neurally mediated hindlimb vascular reflex is stimulated by decreased renal flow rather than pressure.