无针喷射控释双生长因子藻酸盐水凝胶对心肌梗死兔左室重塑及心功能的影响

目的 探讨无针喷射控释双生长因子藻酸盐水凝胶改善心肌梗死兔左室重塑和心功能的可行性.方法 成功建立40只兔心肌梗死模型后,随机分成5组:盐水组、凝胶组、VEGF-A165凝胶组、PDGF-BB凝胶组和双生长因子凝胶组.实验干预8w后,测量平均瘢痕厚度进行形态学分析,采用超声心动图评价心功能,并进行免疫组化检测CD34及α-SMA的表达.结果 凝胶组、VEGF-A165凝胶组、PDGF-BB凝胶组及双生长因子凝胶组的平均瘢痕厚度较盐水组明显增厚(P＜0.05).双生长因子凝胶组心功能较其他各组心功能有所改善(P＜0.05).VEGF-A165凝胶组、PDGF-BB凝胶组及双生长因子凝胶组的微血管及小动脉密度均有所增加,双生长因子凝胶组的血管密度增加最为明显(P＜0.05).结论 无针喷射控释双生长因子藻酸盐水凝胶能够改善心肌梗死左室重塑及心功能,并增加心肌血管密度,为缺血性心脏病治疗提供一种新方法.     

一种携载抗黑热病药物两性霉素B控释系统的研制

采用天然高分子材料 -阴离子聚多糖作为两性霉素 B的载体基质 ,研制高分子材料两性霉素 B控释系统。由离子凝胶作用所产生的阴离子多糖毫微粒 ,其粒径约 3 0～ 1 0 0 nm ,并且对两性霉素 B具有优良的携载性能 ,携载效率超过 90 % ,载药量达 3 5%。体外释放实验表明携载于海藻酸钠粒子上的两性霉素 B可从粒子载体上逐渐释放出来 ,其释放规律几近于零级释放。本实验制得的海藻酸钠粒子两性霉素 B可进一步用于治疗实验犬内脏利什曼病 ,并且为治疗黑热病提供动物实验依据     

成膜法制作壳聚糖管状支架及支架的理化生物特性研究

目的 探讨成膜法自制壳聚糖管状支架的方法及支架的理化学生物特性.方法 利用乙酸溶液制备浓度为8％的壳聚糖乙酸水溶胶,采用成膜方法制管后用NaOH脱下壳聚糖导管,扫描电镜下观察壳聚糖管表面超微结构;并进行溶胀性实验、pH值测定、细胞毒性试验、体外及体内降解实验.结果 壳聚糖管光滑,韧性好,具有三维多孔立体结构,孔径大小不同.壳聚糖管具有膨胀性,中性,无毒,随时间被组织吸收降解,体外降解慢于体内.结论 成膜法自制壳聚糖管状支架可行,其理化生物学特性表明可用作生物可吸收支架.     

具生物活性组织工程血管支架的制备及支架与血管平滑肌细胞的相容性研究

目的 探索缓释血管内皮生长因子(VEGF)的可降解聚乳酸-聚乙醇酸(PLGA)支架的制备及其与血管平滑肌细胞(SMC)的相容性.方法 使用明胶微球做为缓释载体,加载 VEGF 和PLGA 构建组织工程血管支架(VEGF-PLGA)并观察体外 VEGE 释放效果.体外培养大鼠肺主动脉SMC 细胞,随机将培养至第 5 代或第 6 代细胞分为三组:VEGF-PLGA 组、PLGA 组与对照组.并将SMC 种植在 VEGF-PLGA 膜、PLGA 膜片上,对照组不放置膜片.用相差显微镜观察细胞生长情况,采用 MTT 绘制细胞生长曲线,检测细胞增殖和细胞黏附率.结果 (1)VEGF 在体外释放达 14d 以上;(2)SMC 在 VEGF-PLGA 膜片上生长良好;(3)MTT 法检测细胞增殖情况显示,VEGF-PLGA 明显好于其它组(P<0.05),细胞增殖符合细胞生长曲线;(4)细胞黏附率检测显示,三组无明显差异(P>0.05),VEGF-PLGA 对血管平滑肌细胞有良好的相容性.结论 明胶微球载体制备工艺简便,性能优良,VEGF-PLGA 制备方法简便,可在较长时间内持续释放活性 VEGF,对血管 SMC 具有良好的相容性,可用于组织工程血管的进一步构建.     

PDS血管外支架体外毒性和体内相容性的实验研究

目的观察血管外支架材料聚对二氧环己酮（PDS）的体外毒性和体内生物相容性。方法按照医疗器械生物学评价标准，采用体外细胞培养法、MTT法进行PDS体外细胞毒性试验，并进行体内植入降解实验。结果PDS网状支架材料对细胞形态、生长代谢和增殖不构成损害；PDS在体内12周左右开始加速降解，24周完全降解吸收，炎性反应也减退消失，材料区域被新生纤维组织取代，降解过程中未对周围组织产生不良刺激。结论PDS支架材料元细胞毒性，组织反应轻，可满足体内植入的要求。     

多种生长因子纤维蛋白凝胶释放系统的建立

目的：体外建立稳定的纤维蛋白凝胶释放系统,探讨不同浓度的凝血酶、抑肽酶对该系统释放速度的影响;研究该系统是否能作为4种生长因子(血小板衍生生长因子-AB、血管内皮生长因子、表皮细胞生长因子、转化生长因子β1)的缓释载体。方法分别构建不同浓度凝血酶、抑肽酶的凝胶释放系统;以该系统为载体,加入4种生长因子复合物并设立无生长因子的空白对照组,观察各组凝胶于恒温37℃水浴箱的释放情况,通过 ELISA 法检测生长因子浓度。结果凝血酶浓度相同时,抑肽酶浓度越高,纤维蛋白凝胶释放速度越慢(P <0.05);抑肽酶浓度相同时,凝血酶浓度越高,纤维蛋白凝胶释放速度越快(P <0.05);引入生长因子复合物对该系统释放速度没有影响(P >0.05),4种生长因子每日释放的浓度无明显差异(P >0.05)。结论纤维蛋白凝胶释放系统在体外可稳定、缓慢、均匀释放,其中凝血酶随着浓度的增加可加快凝胶释放系统释放,抑肽酶浓度的增加可抑制凝胶系统的释放;纤维蛋白凝胶系统可作为这4种生长因子的缓释载体。     

可注射水凝胶治疗心肌梗死的研究进展

心肌梗死(myocardial infarction,MI)是指由冠状动脉硬化和(或)堵塞引起的局部心肌长期缺血,从而导致心肌弥漫性纤维化和坏死的不可逆病变。水凝胶(hydrogel)作为一种新型生物医学可注射支架材料,因其具有组织相容性好、可塑性强、能人为操控等特点,可作为细胞、药物、细胞因子等的载体对MI患者进行有的放矢的治疗。近年来,学者们已将目光转移到研究MI后细胞分子层面的调控机制,水凝胶则成为此类研究中药物与细胞的最佳载体,本文旨在回顾水凝胶的生物学特点、分类及作用机制,并分析了水凝胶的临床应用现状及局限性,以期为治疗MI提供新的治疗策略。     

人循环内皮祖细胞不同克隆成分的体内外血管生成功能不同

目的探讨成人外周血循环来源的内皮祖细胞不同克隆成分表型特点及体内外血管生成差异。方法密度梯度离心法获得单个核细胞,用含生长因子的内皮培养基接种于纤维连接蛋白包被的培养板中。7d后计数早期克隆并进行下面实验,另1份持续培养直到晚期克隆出现进行相同实验。流式细胞术检测细胞表面抗原,间接荧光染色法鉴定细胞表达假血友病因子。胶原凝胶细胞体外种植及裸鼠体内移植实验分别测定体外及体内血管生成功能。结果早期克隆再种植不能形成第二代克隆且无体内外血管形成功能,细胞表面主要表达CD14和CD45。晚期克隆在培养21~28d间出现,再种植可形成第二代内皮细胞克隆,并能在体外和裸鼠体内胶原凝胶中形成管腔样结构,细胞表达CD45和CD14显著减少(P<0.001)而CD146明显增加(P<0.01)。结论人外周血单个核细胞在内皮培养条件下可形成早期克隆和晚期克隆,只有晚期克隆表现出干/祖细胞和内皮细胞双重表型特征并具有体内外血管生成功能。     

可注射水凝胶治疗心肌梗死

可注射水凝胶可用来装载生物因子,经微创技术植入体内,达到控释药物的目的,促进心脏组织再生,有望发展成为治疗心肌梗死的方案。该文介绍了可注射水凝胶在治疗心肌梗死方面的作用机制及研究进展。     

己内酯/环氧乙烷共聚物降解行为及生物相容性

目的 研究己内酯/环氧乙烷共聚物(PCL-EO)在体内的降解规律和组织相容性,并对降解性输尿管支架材料的用途进行探讨.方法 20枚PCL-EO试样及20只大鼠分别随机分成5个时间组.实验动物麻醉后,于无菌条件下将消毒后的PCL-EO植入大鼠脊柱肌肉中.分别在2、4、6、8、12 w取出材料及周围组织.测量试件质量、分子量观察大体和微观形态变化.大鼠16只,分成4个时间组,PCL-EO植入大鼠脊柱肌肉中,于2、4、8、12 w,取出植入材料及周围的组织块,用组织学方法分析生物相容性.结果 ①PCL-EO在降解初期分子量下降迅速,随后趋缓,重量的损失滞后于分子量的损失,此种共聚物的降解为无规本体水解过程.②植入2 w时可见局部组织水肿,炎细胞浸润;4 w后,炎细胞数量减少,新生毛细血管形成.结论 PCL-EO 降解缓慢,吸收时间较长,埋植初期组织有炎性反应,此后,炎性反应减轻.PCL-EO适宜用作长期植入输尿管支架材料.     

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.