Relationship of actin filament assembly to clearance of fibrinogen gold, GPIIb-IIIa complexes on spread platelets

Abstract. The present study has evaluated the influence of high concentrations of cytochalasins B and E on the detergent-resistant actin levels in fully spread platelets by PAGE gel electrophoresis, and the effects of the two inhibitors of new actin filament assembly on translocation of fibrinogen gold (Fgn/Au) labelled GPIIb-IIIa receptors on the surface-activated cells. Concentrations of 10^{- 4}m and 10^-5 m cytochalasin B and E reduced detergent-resistant actin in fully spread platelets to levels present in resting discoid platelets in suspension. Despite reduction of actin filaments to levels in resting cells, cytochalasin B did not prevent translocation of Fgn/Au from platelet margins into channels of the open canalicular system (OCS). Similar concentrations of cytochalasin E completely blocked translocation of receptor-ligand complexes and produced a patching phenomenon not observed in previous studies. Rinsing of the spread cells to remove cytochalasin, followed by incubation of the treated platelets in Hank's buffered salt solution (HBSS) restored levels of detergent-resistant actin to those found in untreated, spread platelets. Resting grids of 10 ⁵ m cytochalasin E-treated platelets on drops of HBSS for 15min restored their ability to clear FGN/Au linked to GPIIb-IIIa from exposed surfaces to the OCS, but 10^-4 m cytochalasin E-treated cells remained anergic after incubation on drops of HBSS. Thus a fully assembled cytoplasmic actin filament cytoskeleton does not appear to be essential for translocating receptor-ligand complexes on the platelet surface to the OCS, nor does its presence guarantee that the ability to clear GPIIb-IIIa receptors will be restored.     

Smart Plug泪小管塞治疗水液缺乏型干眼症临床初步观察

目的：探讨Smart Plug泪小管塞治疗水液缺乏型干眼症临床疗效。
　　方法：选取2012-05/2013-04期间我院收治的48例水液缺乏型干眼症患者为研究对象,进行Smart Plug泪小管塞治疗,观察术后临床疗效、基础泪液分泌试验( Schirmer Ⅰtest,SⅠt)、泪膜破裂时间( tear break up time,BUT)、角膜荧光素染色( fluoreseein staining,FL)变化。
　　结果：本组48例患者,显效31例(65%),有效14例(29%),无效3例(6%),总有效率为94%。治疗前,患者SⅠt,BUT,FL分别为3.49±1.24mm/5min,3.15±1.07s,2.52±0.11分。治疗后,患者SⅠt,BUT,FL均明显改善,与治疗前比较,差异具有统计学意义( P<0.05)。1例患者术后有异物感,8 h后栓子脱落;1例患者于术后8 mo出现肉芽组织,泪小管塞脱落。其余病例无下泪小管感染或肉芽肿。
　　结论：Smart Plug泪小管塞治疗水液缺乏型干眼症疗效确切,能够有效缓解临床症状,值得临床推广。     

Regulation of opticin on bioactivity of retinal vascular endothelial cells cultured in collagen

AIM: To investigate the effects of collagen and opticin on the bioactivity of human retinal vascular endothelial cells (hRVECs), and explore its regulations by integrins and RhoA/ROCK1 signal pathway. METHODS: hRVECs were cultured in collagen and treated by opticin, and cell-based bioactivity assays of cell proliferation, migration, and adhesion were performed. The expression of integrin α2, integrin β1, RhoA and ROCK1 were examined with real-time PCR and Western blotting. RESULTS: Collagen could promote cell viability of proliferation and migration (all P<0.05), and enhance the mRNA expression of integrin α2, integrin β1, RhoA and ROCK1 (all P<0.05). Opticin could inhibit proliferation and migration ability of hRVECs cultured in collagen, and reduce the mRNA expression of integrin α2, integrin β1, RhoA and ROCK1 (all P<0.05). CONCLUSION: Collagen and opticin can affect bioactivity of hRVECs, which may be regulated by α2-, β1-integrins and RhoA/ROCK1 signal pathway.     

Inhibition of transport across the hepatocyte canalicular membrane by the antibiotic fusidate

Hyperbilirubinemia is a frequent side effect induced by long-term therapy with the antibiotic fusidate. The aim of this study was to elucidate the molecular mechanisms of fusidate-induced hyperbilirubinemia by investigating its influence on hepatic transport systems in the canalicular membrane. Using canalicular membrane vesicles from rat liver, we determined the effect of fusidate on the adenosine 5'-triphosphate (ATP)-dependent transport of substrates of the apical conjugate export pump, multi-drug resistance protein 2 (Mrp2, symbol Abcc2) and the bile salt export pump (Bsep, symbol Abcb11). Fusidate inhibited the ATP-dependent transport of the Mrp2 substrates 17beta-glucuronosyl estradiol and leukotriene C4, and the transport of cholyltaurine by Bsep with Ki values of 2.2+/-0.3, 7.6+/-1.3, and 5.5+/-0.8 microM, respectively. To elucidate the in vivo implication of these findings, the effect of fusidate treatment on the elimination of intravenously administered tracer doses of 17beta-glucuronosyl estradiol and cholyltaurine into bile was studied in rats. Treatment with fusidate (100 micromol/kg body weight) reduced the biliary excretion rate of 17beta-glucuronosyl [3H]estradiol and [3H]cholyltaurine by 75 and 80%, respectively. Extended treatment of rats with fusidate (100 micromol/kg body weight, three times daily i.p. for 3 days) reduced hepatic Mrp2 protein levels by 61% (P<0.001). Our data suggest that there are at least two different mechanisms involved in the impairment of transport processes and hepatobiliary elimination by fusidate, direct inhibition of transport of Mrp2 and Bsep substrates by competitive interaction and impairment by a decreased level of hepatic Mrp2.     

Role of glutathione conjugate efflux in cellular protection against benzo[a]pyrene-7,8-diol-9,10-epoxide-induced DNA damage

Glutathione (GSH) conjugation of (+)-anti-benzo[a]pyrene-7,8-diol-9,10-epoxide [(+)-anti-BPDE], the activated metabolite of benzo[a]pyrene, is believed to be an important mechanism in detoxification of this environmental and dietary carcinogen. Here, we demonstrate that the intracellular accumulation of GSH conjugate of (+)-anti-BPDE (BPD-SG) caused a statistically significant increase in (+)-anti-BPDE-induced DNA adduction. The relationship between intracellular accumulation of BPD-SG and (+)-anti-BPDE-induced DNA adduction was studied using a canine kidney epithelial cell line (MDCKII) and its variants overexpressing multidrug resistance transporter (MDR1) or canalicular multispecific organic anion transporter (cMOAT; also known as multidrug resistance protein 2). MDR1 and cMOAT are implicated in ATP-dependent efflux of anticancer drugs or GSH-xenobiotic conjugates, or both. The GST activity toward (+)-anti-BPDE in parental MDCKII cells did not differ from that in subline overexpressing MDR1 (MDCKII-MDR1) or cMOAT (MDCKII-cMOAT). Intracellular accumulation of BPD-SG, after a 5- or 10-min incubation with 1 microM (+)-anti-BPDE, was significantly higher in parental (41- to 67-fold) and MDCK II-MDR1 cells (31- to 43-fold) than in the MDCKII-cMOAT cells. Interestingly, the levels of DNA adducts of (+)-anti-BPDE, after a 30-min incubation with 0.1 or 0.5 microM [(3)H](+)-anti-BPDE, were significantly higher (about 2.1- and 1.7-fold, respectively) in parental cells than in the MDCKII-cMOAT cells. The results of the present study indicate that in addition to GSH conjugation, the efflux of BPD-SG may be essential for cellular protection against (+)-anti-BPDE-induced DNA damage.     

Emergency repair of lacrimal canaliculus

Twenty-three patients with canalicular injuries who underwent emergency treatment are presented. A round-tipped pigtail probe was used to position the silicone tube for canalicular intubation. Four patients had the injury in the common lacrimal canaliculus. After tubing both canaliculi, the silicone tube ends were retrieved from the inferior meatus. The rest of the patients had inferior canalicular injury. In those cases, a circle was formed by a silicone tube between the upper and lower canaliculi. The silicone tube was held in place for 4–6 months. After removal of the silicone tube, the lacrimal drainage system was evaluated by the dye disappearance test and radiological methods. The drainage system was patent in all cases with a consequent lack of epiphora.This study was partly presented at the European Appointed 20th National Congress of the Turkish Society of Plastic Surgeons on 5 September 1998.     

显微吻合术治疗外伤性下泪小管断裂56例

目的:探讨下泪小管断裂显微吻合术的疗效。方法:在显微镜下寻找断裂的下泪小管鼻侧断端,以硬膜外导管作为支撑吻合泪小管断端。结果:共56例(56眼)在显微镜下全部吻合,51例成功,5例好转。结论:该手术操作简单,成功率高,临床效果好,值得广泛推广。     

双路泪道插管法行外伤性泪小管断裂吻合术

目的 探讨双路泪道插管法并置管固定治疗泪小管断裂的手术方法及术后效果.方法 23例(23眼)外伤性泪小管断裂,在手术显微镜直视下寻找、吻合断端,以硬膜外导管为支撑物,另一端自上泪小管插入,两端于鼻腔拉出后固定藏于鼻腔内.结果 23例术后泪管冲洗均通畅,1例有轻度溢泪,1例患者诉眼部轻度异物感,所有患者无外观不满意抱怨,均能顺利配合治疗至拔管.结论 双路泪道插管法行外伤性泪小管断裂吻合术,其固定效果牢固,外观较满意,易于被患者接受.     

亚甲兰透明质酸钠在下泪小管断裂吻合术中的应用

目的:探讨寻找泪小管断端方法,提高吻合泪小管成功率。方法:从上泪小点注入亚甲兰透明质酸钠,在显微镜下寻找下泪小管鼻侧断端,行泪小管吻合术。结果:本组患者22例(22眼),经泪小管鼻侧断端亚甲兰透明质酸钠标记明显,寻找断端的成功率100%。术后随访6~12mo,19例患者治愈(86%),3例未愈(14%)。结论:注入亚甲兰透明质酸钠,寻找泪小管断端,方法简便易行,容易成功,值得推荐。     

外伤性泪小管断裂经泪囊逆行探通吻合术

目的：评价下泪小管断裂时经泪囊切开，逆行探查寻找下泪小管鼻侧断端吻合手术的效果。方法：对住院的外伤性泪小管断裂患者105例（105眼），先采用直视法、试探法、注液法和上泪小管环钩法等均不奏效时，即改为泪囊切开，经泪囊逆行探查寻找鼻侧断端行下泪小管断裂吻合术。术后随访并进行统计分析。结果：105例均经半年至5年以上的随访观察，获得解剖复位，自觉不流泪，冲洗通畅者102例（97．14％）；冲洗不通者3例（2．86％）。结论：泪囊切开法找到泪小管鼻侧断端把握性大，继而行下泪小管断裂吻合术成功率高，是疗效肯定可供选择或必须选择的方法。