Comparative DNA protectivity and antimutagenicity studies using DNA-topology and Ames assays

Two experimental techniques, the DNA-topology assay and the Ames assay, were proved to be suitable for monitoring compounds with a genotoxic potential and/or with an antimutagenic effect. Both procedures were used in assaying the acid-mine water (AMW) containing toxic metals and sulfoethyl chitin-glucan (SE-Ch-G), a derivative of chitin-glucan, in which bioprotective activities were detected earlier. It was shown that after toxic metal concentrations were decreased due to AMW dilution to the limits that correspond with those set by the Slovak Technical Norm (STN) for drinking water, AMW was not genotoxic in the Ames assay. As it is possible to detect any single-strand DNA (ssDNA) break in the DNA-topology assay, the SE-Ch-G protective effect against the ssDNA breaks induced by Fe²⁺ in the DNA-topology assay was recorded. SE-Ch-G exhibited the antimutagenic potential after its application simultaneously with diagnostic mutagens in the Ames assay. These results demonstrate the complementarity of both experimental systems.     

抗绿脓杆菌脂多糖单克隆抗体交叉反应性和保护性的初步研究

采用纯化的Ⅰ型绿脓杆菌脂多糖免疫BALB/c小鼠,获得了多株分泌抗脂多糖抗体的杂交瘤细胞系。本文选用其中2株抗体1M4、1M8,对它们的交叉反应性和在小鼠腹腔感染模型中的保护作用进行了探讨。研究表明,它们分别识别脂多糖分子上不同部位的抗原基团。其中识别型特异性多糖侧链的1M4抗体在同型菌攻击前2～4h输入,能显著提高小鼠的存活率(P<0.05);另一抗体1M8虽能与多种革兰氏阴性杆菌起交叉反应,但动物试验中未显示有抗感染保护作用。以上结果提示,脂多糖特异的抗体用于绿脓杆菌感染的临床治疗可能具有良好的前景。     

A predictive score for retinopathy of prematurity by using clinical risk factors and serum insulin-like growth factor-1 levels

AIM: To detect the impact of insulin-like growth factor-1 (IGF-1) and other risk factors for the early prediction of retinopathy of prematurity (ROP) and to establish a scoring system for ROP prediction by using clinical criteria and serum IGF-1 levels. METHODS: The study was conducted with 127 preterm infants. IGF-1 levels in the 1st day of life, 1st, 2nd, 3rd and 4th week of life was analyzed. The score was established after logistic regression analysis, considering the impact of each variable on the occurrences of any stage ROP. A validation cohort containing 107 preterm infants was included in the study and the predictive ability of ROP score was calculated. RESULTS: Birth weights (BW), gestational weeks (GW) and the prevalence of breast milk consumption were lower, respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD) and necrotizing enterocolitis (NEC) were more frequent, the duration of mechanical ventilation and oxygen supplementation was longer in patients with ROP (P<0.05). Initial serum IGF-1 levels tended to be lower in newborns who developed ROP. Logistic regression analysis revealed that low BW (<1250 g), presence of intraventricular hemorrhage (IVH) and formula feeding increased the risk of ROP. Afterwards, the scoring system was validated on 107 infants. The negative predictive values of a score less than 4 were 84.3%, 74.7% and 79.8% while positive predictive values were 76.3%, 65.5% and 71.6% respectively. CONCLUSION: In addition to BW <1250 g and IVH, formula consumption was detected as a risk factor for the development of ROP. Breastfeeding is important for prevention of ROP in preterm infants.     

【In Press】 A predictive score for retinopathy of prematurity by using clinical risk factors and serum insulin-like growth factor-1 levels

AIM: To detect the impact of Insulin-like growth factor1 (IGF-1) and other risk factors for the early prediction of ROP and to establish a scoring system for ROP prediction by using clinical criteria and serum IGF-1 levels. METHODS: The study was conducted with 127 preterm infants. IGF-1 levels in the 1st day of life, 1st, 2nd, 3rd and 4th week of life was analyzed. The score was established after logistic regression analysis, considering the impact of each variable on the occurrences of any stage ROP. A validation cohort containing 107 preterm infants was included in the study and the predictive ability of ROP score was calculated. RESULTS: Birth weights (BW), gestational weeks (GW) and the prevalence of breast milk consumption were lower, Respiratory Distress Syndrome (RDS), Broncohopulmonary Dysplasia (bpd) Necrotizing Enterocolitis (NEC) were more frequent, the duration of mechanical ventilation and oxygen supplementation was longer in patients with ROP (p<0.05). Initial serum IGF-1 levels tended to be lower in newborns who developed ROP. Logistic regression analysis revealed that low BW (<1250 g), presence of intraventricular hemorrhage (IVH) and formula feeding increased the risk of ROP. Afterwards, the scoring system was validated on 107 infants. The negative predictive values of a score less than 4 were 84.3%, 74.7% and 79.8% while positive predictive values were76.3%, 65.5% and 71.6%, respectively. CONCLUSION: In addition to birth weight <1250 g and IVH, formula consumption was detected as a risk factor for the development of ROP. Breastfeeding is important for prevention of ROP in preterm infants.     

血吸虫合成多肽抗原免疫效果的实验研究

人工合成的10个不同血吸虫多肽片段对小鼠进行免疫保护实验，采用200μg／只皮下注射，共免疫3次，每次间隔1周，末次免疫后2周，以（40±2）条日本血吸虫正常尾蚴攻击感染。另设不免疫攻击感染日本血吸虫的小鼠为对照组。实验组小鼠分别获得10．7％～73．6％的减虫率、23．0％～75．9％的减卵率和－11．22％～66．78％的虫卵结节减小率。各实验组血清抗体均为阳性，随时间的延长有增高趋势。实验提示，以寡赖氨酸为母校，连接4个或8个抗原肽的多肽抗原效果比较理想。