HSP70对大鼠肝脏局部缺血再灌注后炎症反应的影响

目的：通过热应激预处理诱导HSP70表达，探讨其对肝脏缺血再灌注损伤后炎症反应的影响。方法:采用大鼠局部缺血再灌注模型（IR组），并在热应激预处理（H+IR组）及槲皮素＋热应激预处理（Q+H+IR组）条件下观察肝脏缺血再灌注后HSP70、ICAM-1的表达及MPO的活性；测定血清ALT和AST的活性；电镜观察肝细胞结构的改变。结果:在H+IR组检测的各时点HSP70表达均明显高于其它两组、对肝脏进行缺血再灌注后，肝细胞损伤较轻，血清ALT、AST升高不明显(P<0.01)；肝组织中ICAM-1表达增加，以再灌注后6 h最显著，MPO活性升高以12 h最为显著，但两者变化均低于IR组和Q+H+IR组(P<0.01)。结论：〖HTSS〗热应激预处理诱导产生HSP70蛋白能够降低大鼠肝脏缺血再灌注损伤过程ICAM-1的表达和MPO活性的改变，进而抑制炎症反应引起的肝脏损伤。     

Deceleration affects anticipatory and reactive components of triggered postural responses

Understanding the physiological and psychological factors that contribute to healthy and pathological balance control in man has been made difficult by the confounding effects of the perturbations used to test balance reactions. The present study examined how postural responses were influenced by the acceleration–deceleration interval of an unexpected horizontal translation. Twelve adult males maintained balance during unexpected forward and backward surface translations with two different acceleration–deceleration intervals and presentation orders (serial or random). “SHORT” perturbations consisted of an initial acceleration (peak acceleration 1.3 m s⁻²; duration 300 ms) followed 100 ms later by a deceleration. “LONG” perturbations had the same acceleration as SHORT perturbations, followed by a 2-s interval of constant velocity before deceleration. Surface and intra-muscular electromyography (EMG) from the leg, trunk, and shoulder muscles were recorded along with motion and force plate data. LONG perturbations induced larger trunk displacements compared to SHORT perturbations when presented randomly and larger EMG responses in proximal and distal muscles during later (500–800 ms) response intervals. During SHORT perturbations, activity in some antagonist muscles was found to be associated with deceleration and not the initial acceleration of the support surface. When predictable, SHORT perturbations facilitated the use of anticipatory mechanisms to attenuate early (100–400 ms) EMG response amplitudes, ankle torque change and trunk displacement. In contrast, LONG perturbations, without an early deceleration effect, did not facilitate anticipatory changes when presented in a predictable order. Therefore, perturbations with a short acceleration–deceleration interval can influence triggered postural responses through reactive effects and, when predictable with repeated exposure, through anticipatory mechanisms.     

Effects of exercise cessation on lipids and lipoproteins in distance runners and power athletes

Summary The purpose of this study was to determine the effects of short-term exercise cessation on lipid and lipoprotein profile and insulin sensitivity in highly trained runners (n=12; mean age 19.9 years) and power athletes (n=12; mean age 24.4 years). Following 14 days of exercise cessation, running time to exhaustion and maximal oxygen uptake decreased by 9.2% and 4.8% (P < 0.05) in the runners, while in the power athletes one repetition maximum squat and bench press did not change (P>0.05). No changes occurred in body composition. Data from a 2-h oral glucose tolerance test revealed an impairment of the glycemic state in all athletes (P<0.05). In contrast, exercise cessation did not significantly (P>0.05) alter plasma levels of cholesterol, triglycerides, and low density (LDL) and high density lipoprotein (HDL). No changes were observed in HDL₂, HDL_2b, and HDL₃ subfractions, LDL diameter, and qualitative LDL pattern (P>0.05). These data thus suggest that despite a decrease in insulin sensitivity, short-term exercise cessation, independent of exercise mode, was insufficient to alter plasma lipid and lipoprotein profiles in well-trained athletes.     

树突状细胞在胆囊癌组织内浸润的研究

目的通过对胆囊癌组织中树突状细胞浸润情况的研究,阐述树突状细胞与肿瘤免疫之间的关系。方法采用免疫组化SP法。结果树突状细胞在胆囊癌组织的浸润程度与年龄、性别和病理组织学类型无关,与病理分化程度呈负相关关系(P<005)。结论树突状细胞在胆囊癌组织的浸润程度与病理分化程度、Nevin分期、肝浸润及淋巴结转移存在密切的关系。树突状细胞的定量检测可作为估计胆囊癌预后的标志。     

大鼠β细胞素蛋白的表达、纯化及生物学活性鉴定

目的:获得大量重组大鼠β细胞素并检测其活性。方法:用PCR法从大鼠肾组织中扩增534bp的β细胞素基因片段,并按读框克隆到原核表达载体pET28a( )中。以构建的重组质粒pET28a-rBTC转化大肠杆菌BL-21(DE3)菌株,在IPTG诱导下表达β细胞素蛋白,表达产物用SDS-PAGE和Westernblot检测。采用镍柱亲和层析法纯化目的蛋白。结果:经IPTG诱导后,在大肠杆菌中可表达相对分子质量Mr为20000的目的蛋白。目的蛋白主要以包涵体的形式表达;表达量约占菌体蛋白总量的20%～30%。表达的目的蛋白与抗His标签抗体具有良好的反应性。结论:大鼠β细胞素基因在PET表达系统中得到高效表达;蛋白复性后能有效地促进NIH3T3细胞的体外增殖。     

抗肝癌细胞噬菌体单链抗体库的构建及筛选

构建抗人肝癌细胞单链抗体库 ,从中筛选与肝癌细胞特异结合的高亲和力单链抗体。从HepG2细胞免疫的BALB/c小鼠脾脏提取总RNA ,RT PCR扩增小鼠抗体重、轻链可变区基因 ,用 (Gly4Ser) 3 连接肽基因 ,经重叠延伸反应 ,在体外将VH 和VL 连接成单链抗体 (scFv)基因 ,并克隆入噬菌粒载体pCANTAB5E中 ,构建噬菌体单链抗体库。以HepG2细胞为抗原对抗体库进行淘选 ,ELISA法鉴定各单克隆与肝癌细胞的结合活性 ,并对阳性克隆进行表达。成功构建了库容为 1 1× 10 6抗肝癌细胞的噬菌体单链抗体库 ,经筛选得到了与HepG2细胞具有较强结合能力的单链抗体 ,实现了scFv在大肠杆菌中的可溶性表达。序列测定结果表明 ,VH 和VL 基因符合小鼠抗体可变区特征 ,scFv基因拼接正确     

Neurologic sequelae of domoic acid intoxication due to the ingestion of contaminated mussels

In late 1987 there was an outbreak in Canada of gastrointestinal and neurologic symptoms after the consumption of mussels found to be contaminated with domoic acid, which is structurally related to the excitatory neurotransmitter glutamate. We studied the neurologic manifestations in 14 of the more severely affected patients and assessed the neuropathological findings in 4 others who died within four months of ingesting the mussels. In the acute phase of mussel-induced intoxication, the patients had headache, seizures, hemiparesis, ophthalmoplegia, and abnormalities of arousal ranging from agitation to coma. On neuropsychological testing several months later, 12 of the patients had severe anterograde-memory deficits, with relative preservation of other cognitive functions. Eleven patients had clinical and electromyographic evidence of pure motor or sensorimotor neuronopathy or axonopathy. Positron-emission tomography of four patients showed decreased glucose metabolism in the medial temporal lobes. Neuropathological studies in the four patients who died after mussel-induced intoxication demonstrated neuronal necrosis and loss, predominantly in the hippocampus and amygdala, in a pattern similar to that observed experimentally in animals after the administration of kainic acid, which is also structurally similar to glutamate and domoic acid. We conclude that intoxication with domoic acid causes a novel and distinct clinicopathologic syndrome characterized initially by widespread neurologic dysfunction and then by chronic residual memory deficits and motor neuronopathy or axonopathy.     

Lysosomal storage in human skeletal muscle

Skeletal muscle is involved symptomatically in two lysosomal storage diseases, acid maltase deficiency and a similar condition in which enzyme levels are normal. Asymptomatic storage in skeletal muscle cells is found in Batten-Kufs' disease (ceroid lipofuscinosis), Fabry's disease, and mannosidosis, as well as in rare patients with an unidentified storage disease. Other cell types (vascular endothelium, smooth muscle, fibroblasts, satellite cells) within the confines of the biopsy specimen may reveal storage in other diseases. The differential diagnosis involves predominantly both normal and abnormal conditions in which acid phosphatase activity is prominent in cells.     

Characterization of acaricide resistance in Rhipicephalus sanguineus (latreille) (Acari: Ixodidae) collected from the Corozal Army Veterinary Quarantine Center, Panama

Rhipicephalus sanguineus (Latreille) were collected from the Corozal Army Veterinary Quarantine Center in Panama and characterized for resistance to five classes of acaricides. These ticks were highly resistant to permethrin, DDT, and coumaphos; moderately resistant to amitraz; and not resistant to fipronil when compared with susceptible strains. Resistance to both permethrin and DDT may result from a mutation of the sodium channel. However, synergist studies indicate that enzyme activity is involved. The LC50 estimate for permethrin was lowered further in the Panamanian strain then in susceptible strains with the addition of triphenylphosphate (TPP), but not with the addition ofpiperonyl butoxide (PBO). This suggests that esterases and not oxidases are responsible for at least some pyrethroid resistance. Elevated esterase activity and its inhibition by TPP were confirmed by native gel electrophoresis. The LC50 estimate obtained for coumaphos in the Panamanian strain was not lowered further than what was observed for susceptible strains by the addition of TPP or PBO. This indicates that enzyme activity might not be involved in coumaphos resistance. Resistance to amitraz was measured through a modification of the Food and Agriculture Organization Larval Packet Test. All tick strains were found to be susceptible to fipronil.