Use of 4-methylumbelliferyl-6-sulpho-2-acetamido-2-deoxy-β-D-glucopyranoside for prenatal diagnosis of tay-sachs disease using chorionic villi

Prenatal diagnosis of Tay-Sachs disease was performed using the sulphated substrate 4- methylumbelliferyl-6-sulpho-2-acetamido-2-deoxy-β-D-glucopyranoside to detect hexosaminidase A in chorionic villi. The presence or absence of hexosaminidase A in villi was detected by both a quantitative enzyme assay, and by a rapid, novel procedure which permitted visual discrimination between normal and affected villi.     

[HgI4-(R6G)2]n体系的共振散射光谱法测定微量汞(Ⅱ)的研究

在pH值=4.0的条件下,Hg2 ,I-与罗丹明6G(R6G)形成三元离子缔合物.由于HgI4(R6G)2分子间存在较强的分子间作用力和疏水作用力而生成[HgI4-(R6G)2]n纳米微粒.在320 nm处产生一灵敏共振散射(即共振瑞利散射)光谱峰.Hg质量浓度在0.004～0.36 mg·L-1范围内与共振散射光强度呈现出良好线性关系.实验结果表明,本法具有灵敏度较高、选择性较好等特点.用于水样中微量Hg的测定,效果良好.     

Isolated choroid plexus cysts—the need for routine offer of karyotyping

The management of isolated fetal choroid plexus cysts remains controversial. We have prospectively studied 15 565 pregnancies at two large obstetric units for the presence of choroid plexus cysts. In all cases where cysts were present at 19 weeks' gestation or greater, and were multiple, bilateral or solitary and greater than 5 mm maximum diameter, women were offered amniocentesis or placental biopsy, irrespective of the presence or absence of other abnormalities. Choroid plexus cysts were present in 152 (0·98 per cent) of cases. Four cases (2·6 per cent) of autosomal trisomy (three of trisomy 18, one of trisomy 21) were detected on prenatal karyotyping. In all cases, choroid plexus cysts were the only detectable prenatal anomaly. This study and a review of other large studies do not support the view that isolated choroid plexus cysts are a benign variant, the risk of trisomy being 1 in 82. Until further evidence is available, we recommend that cases of isolated fetal choroid plexus cysts at 19 weeks' gestation or greater should be offered prenatal karyotyping.     

Degradation of 2,6-di-tert-butylphenol by an isolated high-efficiency bacterium strain

An aerobic bacterium strain, F-3-4, capable of effectively degrading 2,6-di-tert-butylphenol(2,6-DTBP), was isolated and screened out from an acrylic fiber wastewater and the biofilm in the wastewater treatment facilities. This strain was identified as Alcaligenes sp. through morphological, physiological and biochemical examinations. After cultivation, the strain was enhanced by 26.3% in its degradation capacity for 2,6-DTBP. Results indicated that the strain was able to utilize 2,6-DTBP, lysine, lactamine, citrate, n-utenedioic acid and malic acid as the sole carbon and energy source, alkalinize acetamide, asparagine, L-histidine, acetate, citrate and propionate,but failed to utilize glucose, D-fructose, D-seminose, D-xylose, sedne and phenylalanine as the sole carbon and energy source. The optimal growth conditions were determined to be: temperature 37℃, pH 7.0, inoculum size 0.1% and shaker rotary speed 250 r/min. Under the optimal conditions, the degradation kinetics of 2,6-DTBP with an initial concentration of 100 mg/L was studied. Results indicated that 62.4% of 2,6-DTBP was removed after 11 d. The degradation kinetics could be expressed by Eckenfelder equation with a half life of 9.38 d. In addition, the initial concentration of 2,6-DTBP played an important role on the degradation ability of the strain. The maximum initial concentration of 2,6-DTBP was determined to be 200 mg/L. Above this level, the strain was overloaded and exhibited significant inhibition.     

Trisomy 8 mosaicism in chorionic villus sampling: Case report and counselling issues

We report an unusual case involving chorionic villus sampling (CVS) and trisomy 8 mosaicism. CVS showed a normal direct preparation while the culture showed mosaicism for trisomy 8. Subsequent amniocentesis revealed only normal chromosomes. A peripheral blood culture after birth revealed low-level trisomy 8 mosaicism. The patient appeared phenotypically and developmentally normal at 30 months of age. We conclude that prenatal counselling for similar cases needs to include the rare but real possibility that chromosome mosaicism detected prenatally may be found postnatally with largely unknown consequences. Secondly, low-level chromosomal mosaicism may be more common than previously recognized. Thirdly, very low-level trisomy 8 mosaicism may be compatible with a normal phenotype but long-term follow-up is required. And lastly, the use of fetal blood sampling is questionable in these cases because the phenotype may not be accurately predicted. Further studies of such cases are needed to address these important and unanswered issues, including the potential implication of mosaicism on academic performance and cognitive functioning.     

海泡石、炉渣、改性钢渣吸附处理垃圾渗滤液中Cr(Ⅵ)的对比研究

为了选择低成本、高效果的处理垃圾渗滤液的吸附剂,本文通过静态吸附试验对比研究了海泡石、炉渣、改性钢渣对垃圾渗滤液中Cr6+的吸附规律,结果表明:吸附平衡时,炉渣对垃圾渗滤液中Cr6+的吸附量最大,为0.001 8mg/g,海泡石次之,为0.001 5mg/g,改性钢渣为0.000 9mg/g;酸性环境及低浓度有利于炉渣、改性钢渣吸附垃圾渗滤液中的Cr6+,且pH值及初始浓度对海泡石吸附垃圾渗滤液中Cr6+的效果影响较小;经综合比较,炉渣吸附性能最为优异。该研究成果可为开发新型吸附剂提供依据。     

离子液体[omim][PF_6]的生物降解性研究

以[omim][PF6]为C、N、P营养源驯化活性污泥,考察驯化前后不同活性污泥接种微生物时离子液体的生物降解性,以及在支链上添加酯基对离子液体生物降解性的影响;同时,探讨经过驯化的活性污泥对1-甲基-3-辛基咪唑阳离子基团([omim]+)生物降解的途径.结果表明,通过在支链上添加酯基,可以改善离子液体的生物降解性;以普通的活性污泥为接种微生物的密闭瓶实验表明,[omim][PF6]的生物降解率<20%,属于难生物降解的物质,进入环境后可能产生较长时间的积累;以经过驯化的活性污泥为接种微生物时,可以提高[omim][PF6]的生物降解率到60%左右;在[omim]+的生物降解过程中,会产生1-甲基咪唑阳离子的积累;对[omim]+的生物降解产物的HPLC-MS/MS分析,初步推测[omim]+的生物降解途径.     

染料壳聚糖微球的制备及对Cr~(6+)的吸附研究

以反相悬浮交联法制备了壳聚糖微球载体(CS),并偶联染料配体(CibacronBlueF3GA),制得了染料亲和吸附剂(CB-CS)。通过扫描电镜对其进行表征,结果表明,该吸附剂粒径均匀,平均粒径在400μm左右,而且表面相当光滑;红外光谱数据证明染料配体的偶联是成功的。然后采用静态法研究了CB-CS树脂对废水中Cr6+的吸附性能。实验结果表明CB-CS树脂对Cr6+具有很好的吸附性能,吸附的最佳条件是:pH值3~4,吸附时间为80min。使用CB-CS树脂处理电镀废水中Cr6+,吸附率达到了96%,而且吸附后的CB-CS树脂可以再生使用。     

米糠在微波条件下解毒铬渣中六价铬的研究

铬渣中含有毒性较强的六价铬化合物,其严重污染环境。为探讨米糠解毒铬渣的可行性,以米糠作为解毒铬渣的材料,在微波条件下对铬渣中的六价铬进行解毒实验研究。利用正交实验对铬渣中六价铬的去除条件进行了优化。在此基础上,开展单因素实验进一步研究确定了铬渣中六价铬去除的最佳条件,并对解毒后的含铬米糠是否具有危险废物的浸出毒性进行了探讨。实验结果表明,当米糠与铬渣质量比为2.5:1,微波作用时间为5min,微波功率为900W时铬渣中六价铬的去除率最大,为72.2%,且解毒后米糠中六价铬的浸出较小,低于国家最高允许浓度标准。