大鼠脑缺血动物模型研究现状与展望

脑缺血实验动物模型是研究脑缺血发病机制及治疗途径的必备工具.本文综述了常见全脑和局灶性大鼠脑缺血动物模型的分类与制备方法,分析了制备过程中的影响因素,介绍了模型的评价方法与指标,指出了大鼠脑缺血动物模型研究的发展趋势.     

缺血性脑损伤的动物模型及其评价方法

脑缺血的实验研究对于理解缺血性脑损伤的发病机制具有重要的作用,但与临床治疗策略的相关性存在一定的局限性,主要原因之一就是实验动物模型和实验方法 不能或只能部分重复自然脑缺血的病理生理学过程.文章对常用的实验动物模型及其体外和体内评价方法 做了综述.     

非酒精性脂肪性肝病体外模型的研究进展

非酒精性脂肪性肝病发病率逐年上升,其治疗手段有限,对其发病机制的研究是当前热点。为了更好地阐明其发病机制,迫切需要开发先进、安全、有效的体外模型或体内模型,以了解并制订针对该疾病的治疗策略。本文回顾了目前常用于非酒精性脂肪性肝病临床前研究的体外模型,并讨论了其各自的优缺点,为研究非酒精性脂肪性肝病发病机制及治疗提供理论依据。     

大鼠脑缺血神经功能缺损行为学评价的研究进展

目前在世界范围内,急性缺血性卒中是成人致死、致残的主要原因之一[1]。动物脑缺血模型的研究对探索大脑缺血的发病机制必不可缺。大脑中动脉（MCA）狭窄或闭塞[2],是造成供血区卒中常见的原因。故用线栓法制成的可逆性大脑中动脉阻塞（middle cerebral artery occlusion,MCAO）模型是最常用的局灶性脑缺血模型。评价脑缺血严重程度的方法很     

肝脏肿瘤体外培养模型的应用与研究进展

肝癌正逐渐成为世界各国公众健康的重要负担,而各种抗癌药物在肝癌的治疗中扮演着重要的作用,正确的选择药物,将显著改善患者预后.体外肝癌细胞培养模型是研究肝癌发病机制以及药物筛选的重要途径.长期的实践证明传统的二维药物筛选方法无法真实的再现肿瘤复杂的耐药机制,三维体外肝癌细胞模型的出现丰富了肝癌体外实验的方法选择的同时,在体外肝癌药物实验敏感性及肝癌细胞病理、生理学体外研究方面也带了较大提高.本文回顾了现有不同类型的肝癌细胞体外培养的主要类型、讨论其各自存在的优势及缺陷,以明确肝癌体外培养模型的发展和研究方向.     

肉苁蓉总苷对清醒小鼠脑缺血再灌注致脑组织生化改变的影响

肉苁蓉总苷(glycosides of cistanche,GCs)具有抗氧化、抗脂质过氧化作用.本研究采用小鼠脑缺血及脑缺血再灌注模型,观察GCs对脑缺血再灌注损伤的保护作用,并阐明其可能作用机制.     

脑缺血后神经细胞凋亡致血管性痴呆的研究进展

在血管性痴呆（vascular dementia,VD）的发病原因中,缺血性脑血管病居首位[1].近年来,诸多研究证明,全脑或局部脑缺血引起的神经细胞亡广是以细胞凋亡为主[2-].利用缺血性损伤制备血管性痴呆动物模型,并对神经细胞凋亡的发生机制进行了研究,但各个机制问的关系尚不明确.我们综述相关机制的研究结果,旨在探讨机制间的相互联系,明确脑缺血致血管件痴呆中神经细胞凋亡的作用.     

雌激素对沙土鼠脑缺血再灌注损伤的影响

近年来 ,一些研究提示老年期雌激素水平的变化与缺血性脑血管病的发病及病程有一定联系 ,但雌激素对脑缺血的影响机制还不十分清楚 ,为此 ,我们利用沙土鼠脑缺血再灌注模型 ,观察雌激素对海马区神经细胞凋亡 ,脑组织匀浆中超氧化物歧化酶(ＳＯＤ)、谷氨酸 (Ｇｌｕ)含量的影响。     

基质金属蛋白酶与缺血性脑损伤

动物模型研究显示,脑缺血再灌注时,基质金属蛋白酶(MMP)表达异常,提示其与脑缺血再灌注损伤有关,尤其是MMP-2、MMP-3和MMP-9,在急性缺血性脑血管病的发病机制中起着重要作用.了解MMP在脑缺血再灌注损伤中的表达、作用、影响其表达的因素及有关抗体的研究和应用,可为脑梗死的早期诊断、预防和治疗提供一种新的选择.     

调节性T淋巴细胞与缺血性卒中

卒中是一种高致死率和高致残率的脑血管病类型,其中缺血性卒中约占80％.目前认为,炎症机制在缺血性卒中的病理生理学进展中发挥重要作用.外周T淋巴细胞在脑缺血后24 h内浸润受损区域,参与脑组织炎症过程的进展.作为T淋巴细胞的一个亚群,调节性T细胞主要定位于缺血半暗带,但目前对其在缺血性脑损伤中的作用仍存在着争议.研究调节性T细胞在脑缺血中的作用机制,有助于进一步认识缺血性卒中的发病机制和发现新的治疗靶点.     

The immunoneuroendocrine role of melatonin

Abstract: A tight, physiological link between the pineal gland and the immune system is emerging from a series of experimental studies. This link might reflect the evolutionary connection between self-recognition and reproduction. Pinealectomy or other experimental methods which inhibit melatonin synthesis and secretion induce a state of immunodepression which is counteracted by melatonin. In general, melatonin seems to have an immunoenhancing effect that is particularly apparent in immunodepressive states. The negative effect of acute stress or immunosuppressive pharmacological treatments on various immune parameters are counteracted by melatonin. It seems important to note that one of the main targets of melatonin is the thymus, i.e., the central organ of the immune system. The clinical use of melatonin as an immunotherapeutic agent seems promising in primary and secondary immunodeficiencies as well as in cancer immunotherapy. The immunoenhancing action of melatonin seems to be mediated by T-helper cell-derived opioid peptides as well as by lymphokines and, perhaps, by pituitary hormones. Melatonin-induced-immuno-opioids (MHO) and lymphokines imply the presence of specific binding sites or melatonin receptors on cells of the immune system. On the other hand, lymphokines such as -γ-interferon and interleukin-2 as well as thymic hormones can modulate the synthesis of melatonin in the pineal gland. The pineal gland might thus be viewed as the crux of a sophisticated immunoneuroendocrine network which functions as an unconscious, diffuse sensory organ.     

Response of rat pineal melatonin to calcium, magnesium, and lithium is circadian stage dependent

Abstract: Herein we documented the response of pineal melatonin production to electrolytes known to be effective on pineal function in view of a possible circadian stage dependence. We studied the release of melatonin by perifused rat pineal glands at 2 different circadian stages corresponding to the middle of the light and dark periods, i.e., respectively, 7 and 19 HALO (Hours After Light Onset, L:D = 12:12). The initial efflux rates were, as expected, much higher in the perifusates of glands removed from rats sacrificed during the dark phase than of those removed during the light phase. After 3 hr of perifusion, melatonin release reached similar levels which were found constant up to the 8th hr of perifusion, whatever the circadian stage. Perifusion of the glands with physiological concentrations for the rat of calcium (5.2 mmol/1) and magnesium (1.34 mmol/1) resulted in a stimulatory effect on the pineal glands removed from rats sacrificed in the middle of the dark period (19 HALO), whereas no effects were observed on the pineal glands removed from rats sacrificed during the light (7 HALO). Lithium (0.28 and 0.55 mmol/1) was ineffective on melatonin release in pineal glands removed 7 and 19 HALO. Our results show differences in the initial efflux rates of melatonin and in the response of perifused pineal glands to calcium and magnesium according to the circadian stage.     

Changes in connexin43, the gap junction protein of astrocytes, during development of the rat pineal gland

Abstract: The abundance of gap junctions between rat pineal astrocytes formed by connexin43 (Cx43) was studied during development. Levels and distribution of Cx43 were measured by immunoblotting and indirect immunofluorescence, respectively. The amount of Cx43 in cells located within the gland was low until about the 7th postnatal day and increased to adult values between the 14th and 21st days postpartum. Although astrocytes, recognized by their vimentin immunoreactivity, were scarce before birth, they were abundant by the 7th postnatal day suggesting that the low levels of Cx43 found at this age corresponded to a low expression of this protein. Localization of the immunoreactivity to Cx43 and vimentin showed a close correlation, indicating that mature or immature pineal astrocytes form gap junctions made of Cx43. Since Cx43 levels attained their adult values at about the time the innervation and the functional state of the gland reached maturity (2–3 weeks after birth), it is proposed that astrocyte gap junctions are involved in the function of the adult rat pineal gland.     

Conservative management of perforated duodenal diverticulum： A case report and review of the literature

Duodenal diverticula are a relatively common condition. They are asymptomatic, unless they become complicated, with perforation being the rarest but most severe complication. Surgical treatment is the most frequently performed approach. We report the case of a patient with a perforated duodenal diverticulum, which was diagnosed early and treated conservatively with antibiotics and percutaneous drainage of secondary retroperitoneal abscesses. We suggest this method could be an acceptable option for the management of similar cases, provided that the patient is in good general condition and without septic signs.     

Presence of immunoreactive growth hormone and prolactin in the ovine pineal gland

Abstract: The use of antisera raised against bovine growth hormone (GH) and ovine prolactin (PRL) enabled the detection of related immunoreactive (ir) sequences of proteins in ovine pineal tissue. The isolation of PRL-like ir-material was accomplished using a 0.25 M ammonium sulphate (pH 5.5) extraction followed by ethanol precipitation, whereas the resulting 2.0 M ammonium sulphate (pH 7.0) precipitate contained a GH-like immunoreactivity. Gel chromatography of the GH-like immunoreactivity (Sephadex G-100) indicated the presence of several GH-like fragments ranging in the M_r range of 7,000 to 55,000. Analyses of the PRL-like ir-material found in pineal tissue on HPLC using a TSK 545-DEAE column led to the resolution into a single peak of immunoreactivity. A single peak of activity was also observed following chromatofocusing and hydrophobic interaction chromatography of the ir-peak from the TSK 545-DEAE column. The PRL-like ir-material inhibited the binding of [¹²⁵I]ovine PRL-S14 to anti-ovine PRL antibodies without showing an affinity for binding to anti-rat PRL or anti-bovine GH antibodies. Scatchard analysis of the binding of pineal PRL-like ir-material and pituitary ovine PRL-S14 to liver membranes from day-20 pregnant rats revealed similar affinity constants (K_a of 4.7 ± 0.2 × 10⁹ M^-1). In addition, the replication of Nb 2 Node rat lymphoma cells was stimulated by pineal PRL-like ir-material, an effect known to be specific for lactogenic hormones. The pineal PRL-like immunoreactivity appeared on sodium dodecyl sulfate polyacrylamide gels as a single major band of M_r 24,000. The functional status of PRL-and GH-like ir-material in the ovine pineal remains to be determined, but evidence is presented that the overall protein synthesis rate of the rat pineal responded to circulating concentrations of PRL.     

Microbiology of human immunodeficiency virus anorectal disease

PURPOSE: Individuals who are seropositive for the human immunodeficiency virus are at high risk for opportunistic infection and anorectal disorders. Little prospective information is available regarding anorectal pathogens in these patients. METHODS: One hundred sixty-three HIV-seropositive patients presented to the colorectal clinic between 1989 and 1992. Forty-seven (29 percent) patients were thought to have an infectious process and were prospectively studied using a standardized multiculture protocol. RESULTS: Mean age was 33 (range, 19–59) years. All were male; high-risk behavior accounted for 87 percent of HIV transmissions. Presenting complaints included anorectal pain (79 percent), pus per anum (28 percent), and blood per anum (26 percent). Examination revealed perianal tenderness (60 percent), condyloma (38 percent), perianal ulcers (38 percent), and anal fissures (34 percent). Sixty-six sets of cultures were performed; 28 patients had one set, 15 had two sets, and 4 had three sets. Thirty-two of these 47 patients (68 percent) had positive cultures including herpes (50 percent), cytomegalovirus (25 percent),Neisseria gonorrhoeae (16 percent), chlamydia (16 percent), acidfast bacilli (2 percent), and others (9 percent). Six of 32 patients with positive cultures had more than one organism cultured. Sixteen (50 percent) patients with positive cultures were treated medically, 8 (25 percent) were treated surgically and 8 (25 percent) were treated with both modalities. Sixty-one procedures were performed on 17 patients for condylomata. Eighteen patients had 20 procedures for abscesses, 50 percent of whom had positive cultures for other than common bowel flora; all improved. Fourteen patients underwent 33 procedures for perianal fistulas.Mycobacterium fortuitum was cultured from one patient who required 13 procedures for abscesses and fistulas. Forty-five (96 percent) patients were followed for an average of 12.5 months ±2.9 SEM (range, 1–94 months). Symptoms were improved or resolved in 22 of 32 (69 percent) patients with positive cultures and in 11 of 13 (84 percent) with negative cultures. CONCLUSIONS: Specific pathogens may often be identified in human immunodeficiency virus-seropositive patients with anorectal disorders if aggressively sought. Although patients without specific pathogens identified may be expected to improve with planned empiric treatment, positive identification allows more directed therapy.