Assay of cytomegalovirus susceptibility to ganciclovir in renal and heart transplant recipients

Ganciclovir (GCV) prophylaxis or pre-emptive therapy significantly reduce the rate of cytomegalovirus (CMV) disease and viremia, but increase the potential for emergence of ganciclovir-resistant CMV strains. The inhibitor concentration at 50% (IC(50)) of GCV from 156 CMV isolates from 59 renal or heart transplant recipients was calculated by means of a rapid phenotypic susceptibility assay. Twenty-seven strains were from 14 patients undergoing GCV therapy. The IC(50) was higher in patients under the prophylaxis regimen. One CMV strain, from a heart transplant recipient, became GCV-resistant after 1 month of therapy (IC(50)=13.7 micromol/l). These data, together with clinical and virological markers, suggested that a switch to foscarnet was necessary, and good evolution was observed. Thus, assay of CMV susceptibility to GCV could be helpful in clinical management.     

HyTK基因转移联合丙氧鸟苷对人膀胱癌细胞株EJ体外杀伤作用

为探索ＨｙＴＫ基因转移对人膀胱癌的治疗作用，采用单纯疱疹病毒胸苷激酶（ＨＳＶＴＫ）基因转移联合丙氧鸟苷（Ｇａｎｃｉｃｌｏｖｉｒ，ＧＣＶ）对通过逆转录病毒载体转导了ＨｙＴＫ基因的人膀胱癌细胞株ＥＪ细胞（ＥＪ／ＴＫ）进行体外杀伤。对分别培养及混合培养的ＥＪ细胞及ＥＪ／ＴＫ细胞，用不同浓度ＧＣＶ进行处理，然后观察细胞形态改变及测定活细胞数量。结果：在ＧＣＶ作用下，ＥＪ细胞形态及数量与对照组无明显变化；而ＥＪ／ＴＫ细胞受到ＧＣＶ明显杀伤，细胞形态破坏，细胞数量明显减少，含１０％ＥＪ／ＴＫ的混合培养细胞就可观察到很明显的杀伤作用。表明：转导ＨｙＴＫ基因的ＥＪ细胞获得了对ＧＣＶ的敏感性，并存在很强的“旁观者效应”。提示ＨｙＴＫ基因转移联合ＧＣＶ可能适用于人膀胱癌治疗。     

TK/GCV、CD/5-Fc双自杀基因系统治疗结肠癌的实验研究

目的观察胸苷激酶/丙氧鸟苷(TK/GCV)、胞嘧啶脱氨酶/5-氟胞嘧啶(CD/5-Fc)双自杀基因系统对结肠癌的治疗效果,并结合研究结果进行作用机理的分析。方法采用培养细胞移植法,将人结肠癌细胞系SW480接种于裸鼠背部皮下,建立裸鼠人结肠癌移植瘤模型。将32只裸鼠随机分为4组:空白对照组,TK/GCV治疗组,CD/5-Fc治疗组,TK/GCV CD/5-Fc联合治疗组,每组8只。TK/GCV CD/5-Fc采用逆转录病毒介导,采用瘤体内直接注射法,同时腹腔注射GCV、5-Fc治疗,观察各组小鼠的生存状况及肿瘤体积、瘤重、肿瘤生长抑制率、常规病理、生存期等指标,比较观察各治疗组的治疗效果及对荷瘤裸鼠存活的影响。结果各治疗组裸鼠人结肠癌移植瘤的生长均受到显著抑制,治疗后各组体积数增加(P<0.05),治疗组裸鼠存活期显著延长,TK/GCV CD/5-Fc联合治疗组效果最好,疗效q值=1.675>1.15,即TK/GCV、CD/5-Fc有交互协同作用。结论TK/GCV与CD/5-Fc对人结肠癌SW480细胞有明显抑制作用,TK/GCV、CD/5-Fc双自杀基因系统效果更强。     

更昔洛韦治疗婴儿巨细胞病毒肝炎32例分析

目的　分析婴儿巨细胞病毒 (CMV)肝炎的临床特征及观察更昔洛韦的临床疗效。方法　观察更昔洛韦正规治疗的 32例婴儿CMV肝炎治疗前后血清总胆红素水平、肝脏酶 (ALT、AKP、γ -GT)变化及肝脾大小 ,同时观察药物不良反应。结果　婴儿CMV肝炎多以黄疸为首发症状 (87.5 % ) ,多有肝脾肿大 (93 .75 %、46.88% )。应用更昔洛韦治疗后 ,在 (1 3± 3)d后血清胆红素及肝酶下降、肝脾回缩。未见更昔洛韦的明显毒副作用。结论　对以黄疸为首发症状的婴儿应警惕CMV肝炎可能 ,更昔洛韦治疗CMV感染是安全有效的。     

Cytosine deaminase versus thymidine kinase: a comparison of the antitumor activity

The efficacy of single and combination suicide gene therapy was evaluated using a Herpes simplex virus thymidine kinase/ganciclovir system and Escherichia coli cytosine deaminase/5-fluorocytosine system on the rat prostate tumor cell line R3327 AT-1. The wild-type R3327 AT-1 cell line was transfected with a bifunctional fusion gene CDglyTK, which had the advantage that the resulting R3327 AT-1/CDglyTK cell line has the same amount of cytosine deaminase and thymidine kinase molecules. The percentage of viable R3327 AT-1/CDglyTK cells after 96 h incubation with 0.1 micro g/ml ganciclovir or 10 micro g/ml 5-fluorocytosine were 85% and 52% of controls, respectively. The cell viability when both suicide genes systems were activated was 43%. For in vivo analysis, Copenhagen rats were injected subcutaneously with R3327 AT-1 or R3327 AT-1/CDglyTK cells and treated with 30 mg/kg ganciclovir, 500 mg/kg 5-fluorocytosine, or both prodrugs together. A survival of 83% with the thymidine kinase/ganciclovir and 57% with the CD/5-FC could be observed. Only co-administration of thymidine kinase- and cytosine deaminase-specific prodrugs resulted in a 100% recurrence-free survival of the Copenhagen rats with a Dunning R3327 AT-1/CDglyTK prostate tumor and showed an additive cytotoxic effect. Calculation of the degree of activation and the potential of activation can be used to predict the success of a suicide gene therapy. In our case, the cytosine deaminase/5-fluorocytosine system had a low degree of activation (value 40), which is also found in the low response to 5- fluorocytosine in vivo (57% tumor free).     

Pharmacokinetics of ganciclovir in a patient undergoing chronic haemodialysis

The pharmacokinetics of ganciclovir was evaluated in a 73-year old anuric, haemodialyzed patient given 1.25 mg·kg^-1 at the end of each haemodialysis session, three times per week.A biexponential decrease in plasma ganciclovir was observed, with a peak concentration of 3.7 mg·1^-1 followed by a steady state value of 2.6 mg·1^-1 for almost 40 h. The total plasma clearance was 0.05 ml·min^-1·kg^-1, the volume of distribution at steady state was 0.61·kg^-1, the elimination half life was 132 h, the area under curve was 372 g·h·ml^-1, the mean residence time was 190 h, and the percentage of ganciclovir cleared from plasma after a 5 h haemodialysis session was 52.1%.The simulated pharmacokinetics over one month, following the same scheme of administration, did not suggest marked accumulation of ganciclovir. These results were obtained after a reduction of 58% in the recommended dose in patients with impaired renal function.     

Liposomally-entrapped ganciclovir for the treatment of cytomegalovirus retinitis in AIDS patients

Treatment of retinitis by cytomegalovirus (CMV) in AIDS patients requires frequent repetitive injections of intravitreal ganciclovir (GCV). This study was undertaken to establish experimentally whether the intravitreal application of liposomally-entrapped GCV could prolong intraocular therapeutic levels when compared with the intravitreal injection of free GCV, and the clinical effectiveness of this approach in AIDS patients. Intraocular concentration of GCV was determined by means of an ELISA test in rabbit vitreous 2, 3, 7, and 14 days after a single intravitreal injection of either different doses of the free drug (0.2–20 mg) or 1 mg of liposomally-entrapped GCV. After 72 h, only the vitreous of rabbits injected with doses of free GCV greater than or equal to 5 mg showed therapeutic levels of the drug; no GCV was detected after 72 h with any of the doses applied. Moreover, the microscopic study revealed GCV-induced damage in retinal structures in the animals injected with a free GCV dose greater than or equal to 15 mg. Intravitreal injection to rabbits of 1 mg of liposomally-encapsulated GCV showed no retinal toxicity at any of the time points studied, and therapeutic levels were detected up to 14 days after injection (4.67 ± 0.39 g/ml). Five AIDS patients suffering CMV retinitis were injected with 0.5 mg of liposomally-entrapped GCV (2 mg of lecithin). Complete remission of the CMV retinitis was observed already at the third injection of 0.5 mg GCV (one per week) and relapse did not occur during the 2–4 month follow-up of the patients. In view of the results presented, it can be concluded that intravitreal injection of liposomally-encapsulated GCV increases the time period required for reinjections in the treatemnt of CMV retinitis.Abbreviations AIDS acquired immunodeficiency syndrome - AZT zidovudine - CMV cytomegalovirus - GCV ganciclovir     

更昔洛韦治疗小儿水痘34例临床观察

目的:探讨更昔洛韦对小儿水痘的临床疗效及安全性。方法:66例水痘患儿随机分为2组,治疗组34例用更昔洛韦注射液5mg/(kg·d),对照组32例用利巴韦林注射液10mg/(kg·d),两组均每日一次静脉滴注,疗程5d,其他治疗方法相同。结果:治疗组热退及结痂时间较对照组缩短(P<0.05),且两组治疗前后周围血白细胞和中性粒细胞比较均无明显差异(P>0.05)。结论:更昔洛韦对小儿水痘有显著疗效,而且安全。     

HSV-TK/GCV系统在难治性卵巢癌裸鼠移植瘤模型中的实验研究

目的:建立人难治性卵巢癌荷瘤裸鼠模型,用HSV-TK/GCV自杀基因系统治疗模型动物,观察疗效及协同因素。方法:常规培养携带HSV-TK基因的重组逆转录病毒包装细胞PA317,测定病毒滴度。在移植瘤内多点注射包装细胞,观察GCV、ATRA、TPT对移植肿瘤独立及协同治疗后的肿瘤体积变化。治疗结束后分析移植肿瘤组织病理,PCR检测TK基因在NIH3T3细胞及移植肿瘤组织的转导。结果:人卵巢癌标本裸鼠原代移植成功率16.7%,鼠间传代移植成功率89.7%;重组逆转录病毒滴度为6×104cfu/ml;HSV-TK/GCV系统或TPT治疗后肿瘤生长受到抑制(P<0.05),两者联合治疗后,抑制更明显(P<0.05);ATRA灌胃未显示独立或协同治疗作用(P>0.05);HSV-TK/GCV组、TPT组及两者联合组有明显的治疗反应;PCR检测证实,TK基因在NIH3T3细胞及肿瘤组织中的转导。结论:HSV-TK/GCV系统及TPT对人难治性卵巢癌荷瘤裸鼠有单独及协同治疗作用,全反式维甲酸灌胃对人难治性卵巢癌荷瘤裸鼠疗效不明显。     

更昔洛韦、泛昔洛韦治疗带状疱疹的成本-效果分析

目的 评价更昔洛韦注射剂与泛昔洛韦胶囊治疗带状疱疹构成本及其效果。方法 将符合带状疱疹典型临床症状的门诊患者共84例，随机分为两组，分别给予更昔洛韦注射剂与泛昔洛韦胶囊治疗，副反应评价指标按卫生部1994年不良反应制定标准。结果 更昔洛韦与泛昔洛韦的治愈率分别为86．0％和82．9％，显效率分别为100％和95．1％，但泛昔洛韦的成本效果比明显低于更昔洛韦。结论 泛昔洛韦更具有成本-效果优势。