Efficacy of the Chitosan Posttreatment in Calcification Prevention of the Glutaraldehyde-Treated Porcine Aortic Noncoronary Cusp Implanted in the Right Ventricular Outflow Tract in Dogs

Abstract: Calcific tissue failure results in poor performance of the bioprosthetic heart valve. Chitosan post-treatment has been shown to be effective in calcification prevention of the glutaraldehyde-treated bovine pericardium when implanted subdermally in rats for 12 weeks. The present study investigated the effectiveness of the chitosan posttreatment in prevention of calcification of the glutaraldehyde-treated porcine aortic noncoronary cusp 5 months after implantation in the right ventricular outflow tract (RVOT) in mongrel dogs. Either 0.625% glutaraldehyde-treated (Group 1, n = 6) or glutaralde-hyde-chitosan-treated (Group 2, n = 6) porcine aortic noncoronary cusp with the aortic wall was sewn to the RVOT. Gross histological observations showed moderate calcification of the glutaraldehyde-treated cusps, but no calcification was noticed in the glutaraldehyde-chitosan-treated grafts at 5 months. This was confirmed by results of quantitative analyses for calcium in half of each ex-planted cusp with aortic wall. The calcium content of the 0.625% glutaraldehyde-treated cusps (Ca, 40.6 ± 24.9 mg/g dry wt) was significantly (p < 0.01) higher than that of glutaraldehyde-chitosan-treated cusps (Ca, 1.3 ± 0.29 mg/g dry wt). These findings suggest that chitosan post-treatment is effective in complete calcium mitigation of the glutaraldehyde-treated porcine aortic noncoronary cusps implanted in the RVOT in dogs.     

GABA-containing neurons in the thalamus and pretectum of the rodent

Summary Antisera produced by immunizing rabbits with GABA conjugated to bovine serum albumin reacted, after purification, strongly with GABA fixed with glutaraldehyde to rat brain macromolecules, but insignificantly with other fixed amino acids (Storm-Mathisen et al. 1983). Sections through the diencephalon of perfusion-fixed mouse and rat brains showed a highly selective labeling pattern after incubation with these antisera. All cells of the reticular nucleus appeared to be stained. Smaller proportions of stained perikarya occurred in the dorsal and ventral subdivisions of the lateral geniculate body, in the medial geniculate body, in the lateroposterior nucleus, and in all nuclei of the pretectum. Labeled cell bodies were only rarely encountered in the ventrobasal complex, and were not found in the anterior and medial groups of thalamic nuclei. Stained axons were particularly concentrated in the ventrobasal complex, and in the stria medullaris, stria terminalis and inferior thalamic peduncle. The arrangement and density of labeled boutonlike dots varied markedly among nuclei, the highest densities occurring in the paraventricular and parataenial nuclei, and in the ventral subdivision of the lateral geniculate body. The mean staining intensity of the thalamic neuropil was lower than that of nearby structures, such as the hypothalamus and zona incerta. The present results on direct immunocytochemical detection of GABA are consistent with, and extend, data from immunocytochemical studies of the GABA-synthetizing enzyme, glutamic acid decarboxylase.     

三种消毒剂对乙肝病毒灭活效果研究

用正交试验对三种消素剂,戊二醛,戊二醛 氯剂和氯剂 碘剂进行HBsAg和PBeAg消毒试验,发现正交试验因素浓度,作用时间及蛋白质对三种消毒效果均有显著性影响。2%戊二醛作用2′,氯 碘剂5ppm作用5′和1%戊二醛 氯剂作用2′可破坏HBeAg,而三种消毒剂在上述浓度下需10′才能灭活HBsAg。1%戊二醛与200ppm有效氯混合时,其消毒效果与5%戊三醛和0.1%氯 碘剂相同,其效果好于单纯剂,值得进一步推广。     

混合醇改性处理对戊二醛牛心包细胞毒性的影响

目的研究混合醇改性对戊二醛牛心包细胞毒性的影响;并验证0.3%戊二醛保存对改性后的戊二醛牛心包细胞毒性有无影响。方法取新鲜牛心包心前区部分,分三组处理:A组:用0.625%戊二醛固定两周后用0.3%戊二醛保存;B组:牛心包用0.625%戊二醛固定二周后,用混合醇后处理并保存;C组:将B组心包在混合醇中处理2个月后,转入0.3%戊二醛中保存。D组:用玻片作为对照组。将三种心包切成同样大小(2×2cm2),用生理盐水分别漂洗10min3次。然后分别种植同样数目的(4×104)人胚肺成纤维细胞,培养7d后,将细胞洗下来,0.4%台盼兰染色,计算每片心包上的活细胞数。同时对心包片细胞作光镜及扫描电镜(SEM)观察。结果4个组活细胞计数结果:三组心包片上的活细胞数分别为:A组(戊二醛牛心包)(:5.83±2.04)×103;B组(混合醇改性戊二醛牛心包)(:16.67±2.04)×103;C组(0.3%戊二醛保存的混合醇改性牛心包):(18.75±1.12)×103。与对照组([176.25±18.15)×103]相比,三种心包均对细胞增殖有不同程度的抑制。混合醇改性后(B、C组)与未改性戊二醛牛心包(A组)的活细胞数有显著性差异(P<0.001),而B组与C组无显著性差异(P>0.05);光镜细胞形态学观察:对照组细胞生长良好,且形态正常,无死亡细胞。细胞计数时见A、B、C三组均有死亡细胞,尤以A组最多;扫描电镜观察:A组细胞较少,且多为圆球形细胞,大部分为裸露的胶原纤维;B、C组均有较多的细胞覆盖生长,细胞展开,可见细胞分裂相。结论经混合醇处理后的戊二醛牛心包细胞毒性明显降低,但仍有细胞毒性;混合醇改性后的戊二醛牛心包保存在0.3%戊二醛溶液中,其细胞毒性无明显改变。     

多聚环氧化合物预处理同种异体静脉重建犬股动脉的实验研究

目的探索新型交联材料多聚环氧化合物(PolyepoxyCompound,PC)预处理同种异体静脉的实验应用。方法将多聚环氧化合物、戊二醛(Glutaraldehyde,GA)交联后的同种异体犬脉以及自体犬静脉(Fresh)进行30只杂种犬双侧股动脉移植 ,在术后3d、7d、14d、30d、60d、90d各个时间点以多普勒超声检测或DSA造影观测血管通畅情况 ,并取血管进行射电镜观察。结果①在移植后的早期(<14d内) ,PC组、GA组和Fresh组累积通畅率分别为64.20%、42.86%和90.00%。但从移植后30d起 ,GA组累积通畅率急剧下降到6.12% ,而PC组在术后30d、60d和90d的累积通畅率分别为48.15%、21.88 %和13.13% ,在各个观察时间期都较GA组高 ,两组之间累积通畅率曲线的分布有统计学的差异(P<0.05)。Fresh组各时间段的累积通畅率也较GA组高 ,两组之间有统计学上的显著差异(P<0.01)。而PC组和Fresh组累积通畅率曲线的分布无统计学差异(P>0.05) ;②PC组在7d时可见内皮细胞从受体动脉向静脉爬行 ,90d时新生内皮细胞已覆盖静脉表面。GA组14d吻合口处内皮细胞开始爬行 ,但爬行距离较PC组短 ,90d可见内膜面有局灶状分布的新生内皮细胞。Fresh组7d内膜面见残存的内皮细胞 ,30d内皮细胞已重新覆盖内膜面。结论PC处理静脉毒性小于GA处理静脉 ,更有利于内皮细胞生长。     

成人Still病的观察与护理

目的 探讨强氧化离子水与传统的戊二醛溶液对呼吸机管道消毒效果的差异。方法对连续使用24h的呼吸机管道60组随机分为实验组和对照组各30组。实验组采用离子水浸泡进行呼吸机管道的消毒；对照组采用戊二醛溶液浸泡消毒，溶液均没过管道。消毒前后采样进行细菌培养及细菌菌落计数，对2组的消毒效果进行比较。结果消毒前所有样本细菌培养阳性率为100％，强氧化离子水与戊二醛溶液消毒后灭菌率分别为：1min83％及17％；5min94％及33％；30min100％及90％。浸泡后1，5min时2组杀灭率比较，差异有统计学意义（P〈0．01），而浸泡30min后杀灭率比较差异无统计学意义（P〉0．05）。结论对呼吸机管道消毒，强氧化离子水效果优于传统的戊二醛溶液。     

两种方法对口腔印模的消毒效果观察

目的 比较两种消毒方法对口腔印模的清洗效果,探求最为有效的口腔印模消毒方法.方法 将口腔印模120例以消毒方法分为2％戊二醛浸泡组,二氧化氯喷雾组以及阳性对照组,并根据不同菌种分别进行细菌培养后计算抑菌率;比较两种方法的灭菌效果,应用SPSS11.5统计软件对结果进行统计分析.结果 戊二醛浸泡后印模上抑菌率金黄色葡萄球菌为(96.45±0.09)％、大肠埃希菌为(94.37±0.05)％、白色假丝酵母菌为(95.22±0.06)％、溶血链球菌为(94.15±0.07)％,而用二氧化氯喷雾法抑菌率则分别为(92.03±0.06)％、(90.13±0.12)％、(91.14±0.07)％、(90.05±0.10)％,抑菌效果均较好,但由于喷雾不完全,两组间差异有统计学意义(P＜0.05).结论 对不同材料的印模,选择的消毒方法也不同,应综合考虑消毒浓度、时间、方法,以便于选择.     

戊二醛使用频率与时间监测在消化内镜消毒效果中的观察

目的 进一步探讨2％戊二醛消毒液使用有效频率,利用戊二醛使用频率监测消化内镜消毒效果,为消毒剂更换的时间提供科学性的指导.方法 选取2009年1-12月使用5周内的戊二醛,自频数30次开始,以5次为间隔,取样至第100次,共取使用中的戊二醛样本15份及戊二醛原液18份,进行污染菌量、定量杀菌效果监测.结果 使用中的2％戊二醛消毒液污染菌量为0,除频数为85的胃镜表面取样的合格率为85.0％,其余频数的取样合格率均为100.0％.结论 5周内戊二醛可至少使用85次后进行更换,其消毒内镜的效果可靠,将使用频次与使用时间相结合作为消毒剂更换依据更具有科学性.     

In vitro properties and performance of glutaraldehyde-crosslinked bovine pericardial bioprostheses treated with glutamic acid

Calcification is one of the major causes of failure of heart valve bioprostheses (HVBs) derived from glutaraldehyde (GA)‐processed bovine pericardium (BP) or porcine aortic valves. New crosslinking reagent procedures are still far from giving satisfactory results, and this is the main reason why GA is still the reagent of choice for the fixation of native tissue intended for HVB manufacture. Nevertheless, two new findings with respect to GA processing may significantly improve HVB performance postimplantation: the finding that increasing concentrations of GA result in a decrease in calcification; the blocking of free aldehyde usually by nucleophyles or the treatment of processed material at low pH. This work investigates the in vitro properties of BP fixed with GA followed by the treatment with glutamic acid under alkaline conditions in order to prepare BP materials with lower calcification potential postimplantation. In comparison to conventional processing, except for the tensile strength that was slightly lower, elongation and toughness were higher than the accepted values. No significant differences were observed in the performance indexes (mean pressure gradient, mean effective area, regurgitant fraction, performance and efficiency indexes) with wear resistance over 150 × 10⁶ cycles. These results indicate that the processing of BP described in this work may be of potential use in the manufacture of HVBs.     

Methods to reduce the contraction of tissue-engineered buccal mucosa for use in substitution urethroplasty

Background

We previously described the production and clinical outcomes of tissue-engineered buccal mucosa (TEBM) used to treat recurrent urethral strictures. In this study, two patients developed a recurrent stricture and there was also evidence of graft contraction.

Objective

Assess possible preclinical methods to reduce contraction of TEBM.

Design, setting and participants

Using the model of TEBM in use clinically (ie, oral keratinocytes and fibroblasts cultured on de-epidermised acellular dermal scaffold), three methods of reducing TEBM contraction were investigated in vitro.

Interventions

The techniques assessed were pretreatment of de-epidermised dermis (DED) with glutaraldehyde, culture with β-aminopropionitrile (β-APN; a lysyl oxidase inhibitor), and physical restraint of TEBM grafts during culture.

Measurements

Contraction was assessed using serial digital image analysis. The cytotoxicity of the pharmacologic manipulations was assessed using monolayer cultures of oral mucosa cells.

Results and limitations

Control TEBM lost a mean of 45.4% of its original surface area over 28 d of culture. Treating TEBM with glutaraldehyde, β-APN, or mechanical restraint during culture all significantly inhibited graft contraction. Glutaraldehyde treatment was most effective (only 5.5% loss of area with 0.1% glutaraldehyde), followed by mechanical restraint for at least 7 d (21.4% loss of area), and then β-APN (28.7% loss of area). None of the treatments had any significant effect on cell viability. This in vitro study identifies solutions for graft contracture to explore in the clinic.

Conclusions

Glutaraldehyde pretreatment and restraint of TEBM grafts during culture both reduce graft contraction.