C-terminal tail of β-adrenergic receptors: immunocytochemical localization within astrocytes and their relation to catecholaminergic neurons in N. tractus solitarii and area postrema

β-Adrenergic receptors (βAR) in the medial nuclei of tractus solitarii (m-NTS) and area postrema (AP) may bind to catecholamines released from neurons, whereas only the AP has fenestrated capillaries allowing access to circulating catecholamines. Since varied autonomic responses are seen following βAR activation of the dorsal vagal complex, including the m-NTS and AP, we hypothesized that there might be a cellular basis for varied responses to βAR stimulation that depends pn the differential access to circulating catecholamines. Therefore, we comparatively examined the ultrastructural localization of the βAR in relation to catecholaminergic neurons in these regions. An antibody directed against the C-terminal tail (amino acids 404–418) of hamster β-adrenergic receptor (βAR404) was used in this study. The localization of βAR404 was achieved by the avidin-biotin peroxidase complex (ABC) technique in combination with a pre-embed immunogold labeling method to localize tyrosine hydroxylase (TH), the catecholamine-synthesizing enzyme. Within m-NTS and at subpostremal border, labeling for βAR404 was evident along the intracellular surface of plasma membranes of small, apparently distal, astrocytic processes. Astrocytic processes with βAR404-immunoreactivity formed multiple, thin lamellae around TH-labeled and non-TH neuronal cell bodies and dendrites. βAR404-immunoreactive astrocytes also extended end-feet around blood vessels and surrounded groups of axon terminals that were directly juxtaposed to each other. Some, but not all, of these axons demonstrated TH-immunoreactivity. Fewer βAR404-immunoreactive astrocytes were detected in AP, regardless of their proximity to catecholaminergic processes or blood vessels. The present astrocytic localization of βAR404, together with the earlier, neuronal localization of βAR's third intracellular loop, suggest that the βAR may be substantially different between neurons and astrocytes. The regional difference in the prevalence of βAR404-immunoreactive astrocytes suggests that these receptive sites may either: (i) be preferentially activated by catecholamines released from terminals rather than circulating catecholamines; or (ii) be down-regulated in AP due to blood-born substances, such as catecholamines. The extensive localization of βAR in the border between m-NTS and AP also suggests that catecholaminergic activation of these astrocytes may dictate the degree of diffusion of catecholamines which are of neuronal or vascular origin. The specific localization of βAR404-immunoreactivity to the more distal portions of astrocytes suggests the possibility that astrocytes have restrictive distributions of βAR and that the β-adrenergic activation lead to morphological or chemical changes that are also localized to the distal portions of astrocytes. Additionally, the detection of βAR404 in astrocytes contacting non-TH-immunoreactive neurons suggests the possibility for catecholaminergic modulation of non-catecholaminergic neurons via the activation of astrocytes.     

SCHWANN CELLS AND THE REGROWTH OF AXONS IN THE MAMMALIAN CNS: A REVIEW OF TRANSPLANTATION STUDIES IN THE RAT VISUAL SYSTEM

1. We have used peripheral nerve transplants or cultured Schwann cells grafted in association with different types of polymer to study axonal regrowth in the rat visual system. In some instances the glia were co-grafted with fetal tectal tissue. 2. The studies have two main aims: (i) to determine whether retinal axons can be induced to regrow at a site distant from their cell soma, that is, after damage to the brachial region of the optic tract; (ii) to determine whether retinal axons exposed to Schwann cells retain the ability to recognize their appropriate target neurons in CNS tissue. 3. In brachial lesion studies, Schwann cells were placed in the lesion site in association with nitrocellulose papers, within polycarbonate tubes in the presence or absence of a supporting extracellular matrix (ECM), or within polymer hydrogel scaffolds. Autologous sciatic nerve grafts were also used. Immuno-histochemical studies revealed the presence of regenerating axons within all polymer bridges. Regrowth of retinal axons was also seen, however, growth was not extensive and was limited to the proximal 1–1.5 mm of the implants. 4. In target innervation experiments, two surgical paradigms were developed. In one experiment, a segment of sciatic nerve was autografted onto the transected optic nerve in adult rats and the distal end of each graft was placed adjacent to fetal tectal (target) tissue implanted into the frontal cortex. To date, we have not been able to demonstrate selective recognition of target regions within tectal transplants by retinal axons exiting the sciatic nerve implants. 5. In the second experiment, Schwann cells were mixed with fetal tectal cells and co-grafted to the midbrain of newborn host rats. Schwann cells altered the characteristic pattern of host retinal growth into tectal grafts; in some cases axons were induced to grow away from appropriate target areas by nearby co-grafted Schwann cells. 6. In summary, Schwann cell/polymer scaffolds may provide a useful way of promoting the regrowth of damaged axons in the CNS, however: (i) in adults, at least, their effectiveness is reduced if they are located at a distance from the cell bodies giving rise to regenerating axons; (ii) in some circumstances exposure to a peripheral glial environment may affect the capacity of regenerating axons to recognize appropriate target cells in the CNS neuropil.     

内镜下应用保护性套管取上消化道异物

食管、胃异物经内镜取出是目前认可的方法 ,成功率约90 % [1 ] 。但是对部分异物特别是细长锐利性异物取出时 ,易有出血、穿孔合并症 ,且极易伤及食道及咽喉部黏膜 ,甚至出现黏膜撕裂、剥脱及引起嵌顿等严重并发症。大连医科大学第二临床学院消化内科 1 995年 1月～ 2 0 0 3年 5月应用食管保护性套管成功取出食管及胃细长锐利性异物 6 9例 ,无 1例异物造成继发性食管黏膜损伤发生。现报告如下。1　材料和方法1 .1　一般资料①本组 6 9例患者。男 4 2例 ,女 2 7例 ;年龄 2 2岁～ 92岁。误服异物史 :30min～ 7d。②异物种类 :缝被针、铁钉、铁…     

非淋菌性泌尿生殖系感染1186例支原体检测及药敏分析

了解非淋菌性泌尿生殖系感染患者的支原体感染情况及耐药性。方法： 对1186例就诊的患者采集标本进行支原体的培养检测和药敏试验。结果： 通过对1186例就诊患者的支原体检测，芰原体感染的阳性率为51．6％，单纯Uu、Mh感染及混合感染者分别占36.2％，3．0％和12．4％；Uu和Mh的阳性率分别为48．7％和15.3％，美满霉素、交沙霉素和阿奇霉索可作为治疗的首选药物。结论： 美满霉素、交沙霉素和阿奇毒素可作为支原体所致泌尿生殖系感染的首选药物     

阿奇霉素和鱼腥草治疗小儿下呼吸道感染

目的　探讨静脉点滴阿奇霉素和鱼腥草治疗小儿下呼吸道感染的临床疗效及其安全性。方法　采用随机对照分组研究 ,观察组使用阿奇霉素 5～ 10mg/kg ,每日 1次 ,加鱼腥草 1～ 3ml/ (kg·d) ,每日 1次静脉滴注 ,疗程 5～ 7d。对照组选用头孢拉定 5 0～ 10 0mg/ (kg·d)加利巴韦林 10mg/ (kg·d)静脉滴注 ,每日 2次 ,疗程 5～ 7d。结果　观察组痊愈率和有效率分别为 72 .5 %和 89.8% ,而对照组的痊愈率和有效率分别为 4 5 .3%和 73.6 % (P <0 .0 1) ,观察组和对照组的不良反应发生率分别为 13.5 %和 10 .8% (P >0 .0 5 )。结论　阿奇霉素加鱼腥草静脉滴注治疗小儿下呼吸道感染临床疗效确切 ,不良反应较少     

Epidemiology of gastro-intestinal and respiratory tract diseases in rural areas of Varanasi (India)

The pattern of gastro-intestinal (GIT) and Respiratory tract (RTI) diseases in rural areas of the Varanasi district, U.P. (India) was studied from the outpatient (OPD) attendance between July 1985 to June 1986. Out of a total of new patients, 19.71% had respiratory diseases in contrast to 27.9% with GIT disease. A decreasing trend was observed in attendance rates as age advanced. The difference in age distribution of males and females was statistically significant. The attendance rates for GIT diseases were higher in female (29.16%) than in males (25.16%) whereas in RTI, the rates were higher in males (19.39%) than in females (18.77%). The attendance rate was found to be higher in rainy season (23.59%) followed by summer (14.50%). Diarrhoea (15.44%) and upper (URTI) respiratory tract infection (19.93%) occupied the major recorded episodes.     

Is it time to reconsider initial antibiotic treatment strategies for severe urinary tract infections in Europe?

Until recently, most reported cases of bacteraemia caused by multidrug-resistant strains of Enterobacteriacae producing an extended-spectrum beta-lactamase (ESBL) in Europe have been nosocomial in origin. However, increasing numbers of reports of community-acquired bacteraemia and urinary tract infection caused by ESBL-producing microorganisms suggest that the geographical origin of patients should be taken into account as a risk-factor for possible ESBL production. Early identification of patients at high-risk of infection with ESBL-producing microorganisms, based on their geographical origin and travel history, should help to optimise initial antibiotic treatment strategies for severe urinary tract infections in Europe.     

头孢替唑钠与头孢哌酮治疗小儿急性细菌性下呼吸道感染的临床疗效比较

目的:评价头孢替唑钠治疗小儿急性细菌性下呼吸道感染的临床有效性、安全性。方法:轻、中度急性细菌性下呼吸道感染患儿115例分成2组,头孢替唑组58例,予头孢替唑钠20～80mg/(kg·d),溶于10%葡萄糖溶液中,分2次静脉滴注。头孢哌酮组57例,予头孢哌酮50～150mg/(kg·d),分二次静脉滴注。两组均以7~10d为一疗程。结果:头孢替唑钠组与头孢哌酮组的临床有效率分别为93%与91%(P>0.05),细菌清除率分别为92%与89%(P>0.05)。两组均无明显的不良反应。结论:头孢替唑可作为治疗小儿轻、中度急性细菌性下呼吸道感染有效和安全的抗生素。     

The effect of naloxone on the preoperative gastric volume and pH

The effect of 4 mg oral naloxone on preoperative gastric volume and pH of gastric aspirate was studied in a double-blind, randomized study. Twenty patients received 10 ml of naloxone (4 mg) mixed with 10 ml of orange juice, and 20 patients received 10 ml of isotonic saline mixed with 10 ml of orange juice, 2 h before surgery. Gastric content was obtained immediately after intubation of the trachea. No significant difference in gastric volume and pH of gastric aspirate was found between the two groups. It is concluded that naloxone does not affect gastric emptying and gastric acid secretion to a degree great enough to protect against aspiration of gastric contents into the lungs.     

急性梗阻性化脓性胆管炎(附121例分析)

本文对121例急性梗阻性化脓性胆管炎(AOSC)进行了临床分析讨论了诊断及治疗。结果表明,早期诊断,尽快手术治疗,积极防治并发症,是提高疗效降低死亡的关键。肝肾功能衰竭和中毒性休克是本病的主要死因,占死亡总人数的83％,60岁以上的老人不是手术的禁忌症。