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91.
92.
Evidence from animal and human studies suggests that ocular growth is influenced by visual experience. Reduced retinal image quality and imposed optical defocus result in predictable changes in axial eye growth. Higher order aberrations are optical imperfections of the eye that alter retinal image quality despite optimal correction of spherical defocus and astigmatism. Since higher order aberrations reduce retinal image quality and produce variations in optical vergence across the entrance pupil of the eye, they may provide optical signals that contribute to the regulation and modulation of eye growth and refractive error development. The magnitude and type of higher order aberrations vary with age, refractive error, and during near work and accommodation. Furthermore, distinctive changes in higher order aberrations occur with various myopia control treatments, including atropine, near addition spectacle lenses, orthokeratology and soft multifocal and dual-focus contact lenses. Several plausible mechanisms have been proposed by which higher order aberrations may influence axial eye growth, the development of refractive error, and the treatment effect of myopia control interventions. Future studies of higher order aberrations, particularly during childhood, accommodation, and treatment with myopia control interventions are required to further our understanding of their potential role in refractive error development and eye growth.  相似文献   
93.
目的:探究超声在诊断胎儿颜面畸形中的临床价值,进一步分析颜面部畸形与染色体异常的关系。方法:回顾性分析2018年12月-2019年7月在笔者医院超声科行产前筛查的1533例孕妇的资料,以超声筛查胎儿颜面部异常者(超声异常组,n=30)和超声筛查胎儿颜面部正常但具有高危因素者(超声正常高危组,n=66)作为研究对象。记录超声及染色体检查结果,分析颜面部畸形与染色体异常的关系。结果:30例超声筛查颜面部异常胎儿中,8例单纯颜面部异常,22例颜面部异常合并其他异常。超声异常合并其他异常组NT厚度显著高于超声单纯异常组和超声正常高危组,差异有统计学意义(P<0.05)。超声异常组胎儿染色体异变率为20.00%,显著高于超声正常高危组的4.55%,差异有统计学意义(P<0.05)。结论:产前筛查中应用超声诊断可以明显提高染色体异常胎儿的检出率,值得临床推广应用。  相似文献   
94.
Previous studies in the wetland macrophyte Bidens laevis L have demonstrated that the insecticide endosulfan induces a high frequency of somatic chromosome aberrations in anaphase–telophase (CAAT) but no DNA changes as determined by the single cell gel electrophoresis (Comet) assay. Thus, cytogenetic biomarkers appear to be more sensitive to the toxic effects of the insecticide than the DNA molecule in the studied species. For this reason, the goals of this study were to use cytogenetic biomarkers—CAAT and abnormal metaphase—and defense biomarkers such as the activity of the antioxidant enzymes—guaiacol peroxidases (POD), glutathione reductase, and microsomal and cytosolic (m‐ and c‐) glutathione‐S‐transferase (GST)—to evaluate in B. laevis effects caused by a commercial formulation of endosulfan. The frequency of CAAT was increased at 5, 10, 50, and 100 μg/L endosulfan with respect to the negative controls by 3.1, 2.5, 2.5, and 3.2‐fold, respectively while the frequency of abnormal metaphases was also increased at the same concentrations by 3.5, 2.8, 3.2, and 11.3‐fold, respectively. In addition to these aneugenic effects, other abnormalities such as C‐mitosis and chromosome clumping were observed at 10 μg/L endosulfan. On the other hand, POD induction at 0.02, 0.5, 5, and 10 μg/L and m‐GST inhibition at 0.5, 10, and 50 μg/L in plants exposed during 24 h to endosulfan were observed but all of these responses were highly variable. In conclusion, only cytogenetic biomarkers like CAAT in B. laevis can serve potentially as early warning systems to detect environmentally relevant concentrations of endosulfan in aquatic ecosystems. © 2013 Wiley Periodicals, Inc. Environ Toxicol 29: 1063–1071, 2014.  相似文献   
95.
《Toxicology in vitro》2014,28(1):39-45
This study investigates the effects of oxime K048 (730, 200, and 7.3 nM) on the viability and chromosome stability of human peripheral blood lymphocytes (PBLs) after a 30 min exposure in vitro. Cytotoxicity was tested by a viability assay with ethidium bromide and acridine orange. For the evaluation of the genotoxic potential, we used comet assays, cytokinesis-blocked micronucleus (CBMN) assay, and chromosome aberration (CA) analysis. We found acceptable cytotoxicity for K048 (9.7 ± 2.1% non-viable PBL at highest concentration vs. 7.3 ± 2.5% in control; apoptosis dominated over necrosis). Overall primary DNA damage was low and not significantly different from controls. The hOGG1-comet assay showed a slight increase in the level of oxidative DNA damage. In oxime treated PBLs, we found 13–19 MN compared to 15 MN in control cultures. The frequencies and types of CA in oxime-treated PBLs did not significantly differ from controls. K048 showed acceptable biocompatibility at the level of cell viability and chromatin/chromosome integrity. Since no increase in secondary genome damage was detected, the primary DNA lesions may have resulted from treatment-induced cell stress, subsequently becoming repaired and not fixed as chromosome aberrations. The toxicity profile of K048 should be further studied and compared with other clinically relevant oximes.  相似文献   
96.
Abstract: The in situ hybridization technique was used for the localization on human chromosomes of single-copy and repeated sequences and, in addition, for the characterization of altered human chromosomes. Two anonymous clones, single or low-copy, obtained from a human X chromosome library were localized on the distal part of the long arm and in the paracentromeric region of X chromosome, respectively. A genomic fragment of the single-copy thyroglobulin (TG) gene was used to confirm the localization on the distal part of the long arm of chromosome 8. The localization and distribution on human chromosomes of the glyceraldehyde-3-phosphate dehydrogenase (GAPD) multigene family obtained by in situ hybridization and by somatic cell hybrids were compared. A phosphoglycerate kinase (PGK) c-DNA clone, which detects genic and pseudogenic sequences on the X chromosome, was used for the characterization of three small ring markers present in unrelated female patients.  相似文献   
97.
目的:探讨透明晶体摘除联合人工晶体植入术对术眼波前像差及成像质量的影响。方法:对行透明晶体摘除联合人工晶体植入术后12个月以上的28例远视眼患者及未行手术治疗的23例远视眼患者进行了波前像差和角膜地形图的检测,比较分析了4.2mm和6mm瞳孔直径者3~6阶(高阶)像差的均方根值和Zernike4阶球面像差的变化。结果:手术组高阶像差的均方根值比对照组增高40%。手术组全眼、角膜和眼内部(包括晶体和角膜后面)的高阶像差均方根值和球面像差与矫正的屈光度无关。结论:透明晶体摘除联合人工晶体植人术增加了术眼的波前像差,降低了眼的成像质量。  相似文献   
98.
The surgeon's ability to recognize abnormal vascular anatomy has greater importance than ever in modern esophagogastric surgical procedures. Some aberrations of vascular vessels around the stomach found during extensive surgery due to primary cancer of the stomach, cardia and lower esophagus are presented in this paper. The purpose of the prospective study is to evaluate and classify these variations with respect to their impact in visceral surgery. A total of 426 patients who underwent total or extensive gastrectomy and esophagectomy combined with lymphadenectomy, have been analyzed prospectively. For the period of 10 years some vascular aberrations have been found in 54/426 (12.67%) of the patients in the operative field during lymphadenectomy as single or combined anomalies. An arterial perigastric anatomy considered normal in textbooks was found in 372 (87.32%) cases. An accessory left hepatic artery arising from the left gastric artery was found in 19/54 (35.18%), and replaced type in 7/54 (12.96%). The replaced right hepatic artery branching from the superior mesenteric artery was found in 5/54 (7.40%) cases. Replaced and accessory left gastric artery branching from the aorta was found in 8/54 (14.8%); accessory posterior gastric artery was found in 25/54 (44.4%), and abnormalities of the splenic, and subphrenic arteries were found in 6/54 (11.11%). Combined anomalies of both left and right hepatic arteries and variations of the celiac trunk were found in 2/54 (3.70%) cases. Forty-nine cases were classified according to established Michels' typology system. Six cases presented with extremely rare variations and remain unclassified. Possible intraoperative problems concerning postoperative complications are also emphasized.  相似文献   
99.
目的探讨产前诊断指征和产前诊断胎儿染色体异常间的关系。方法选择2018年6月至2018年12月于贵港市人民医院就诊的孕妇100例,收集所有孕妇产前诊断指征的资料,同时收集羊膜腔穿刺术检测胎儿染色体核型分析的结果。结果胎儿染色体异常共9例,总异常率占9.00%,其中无创基因检测异常组的胎儿染色体异常检出率为60.00%,明显高于高龄组的3.03%、唐氏筛查高危组的5.26%及胎儿超声异常组的7.69%,差异均有统计学意义(P<0.05);夫妇染色体异常组的胎儿染色体异常检出率为50.00%,明显高于高龄组,差异均有统计学意义(P<0.05);高龄组、唐氏筛查高危组、胎儿超声异常组间异常检出率无明显差异(P>0.05)。结论产前诊断指征与胎儿染色体异常密切相关,羊膜腔穿刺行染色体核型分析,能够有效检出胎儿染色体异常,对于有产前诊断指征的孕妇应尽早接受产前诊断,以降低新生儿出生缺陷的发生率。  相似文献   
100.
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