Genetic recombination as a major cause of mutagenesis in the human globin gene clusters

ObjectivesHomologous recombination is a frequent phenomenon in multigene families and as such it occurs several times in both the α- and β-like globin gene families. In numerous occasions, genetic recombination has been previously implicated as a major mechanism that drives mutagenesis in the human globin gene clusters, either in the form of unequal crossover or gene conversion. Unequal crossover results in the increase or decrease of the human globin gene copies, accompanied in the majority of cases with minor phenotypic consequences, while gene conversion contributes either to maintaining sequence homogeneity or generating sequence diversity. The role of genetic recombination, particularly gene conversion in the evolution of the human globin gene families has been discussed elsewhere.ConclusionHere, we summarize our current knowledge and review existing experimental evidence outlining the role of genetic recombination in the mutagenic process in the human globin gene families.     

Hangman骨折的治疗方法选择及疗效分析

目的:探讨不同类型Hangman骨折的治疗方法选择和治疗效果。方法:2006年1月~2009年6月我院脊柱外科共收治Hangman骨折患者29例,男20例,女9例;年龄17～74岁,平均32岁。采用Levine-Edwards分类法:Ⅰ型8例,Ⅱ型12例,Ⅱa型7例,Ⅲ型2例。所有患者均先行牵引复位后再采用Halo-vest外固定或手术内固定治疗,其中Ⅰ型患者均采用Halo-vest外固定;有硬膜前方受压的5例Ⅱ型和1例Ⅲ型患者采用前路C2/3椎间盘摘除、椎体间植骨、前路钛板固定术(A术式),无硬膜前方受压的5例Ⅱa型患者采用后路C2椎弓根螺钉固定术(B术式),2例Ⅱa型、7例Ⅱ型、1例Ⅲ型患者采用后路C2-3椎弓根侧块螺钉钛板/棒内固定术(C术式)。术后根据颈椎X线片上骨折愈合情况、临床症状及颈椎活动功能改善情况评价各种治疗方法的疗效。结果:术后随访6~40个月,平均18个月。末次随访时8例采用Halo-vest外固定治疗的Ⅰ型患者疗效优良5例,可2例,差1例(骨折未愈合,后经A术式治疗,12周后C2-3节段融合,疗效为良)。6例A术式及5例B术式手术患者均在12周后获得骨性融合,疗效均为优良。10例采用C术式手术患者中,1例Ⅱ型患者畸形融合,1例Ⅱ型未融合,8例疗效优良。结论:根据Levine-Edwards分型选择治疗方式治疗Hangman骨折多数患者可获得优良疗效。     

非特异性脊柱感染的诊断与治疗

目的:探讨非特异性脊柱感染的临床特征及治疗方法.方法:回顺性分析我科2006年9月～2012年2月收治的16例非特异性脊柱感染患者的临床资料,男6例,女10例,年龄23～66岁,平均53.5岁.腰椎8例,胸腰段6例,胸椎2例.患椎处剧痛14例,轻度胀痛2例,11例X线片显示患椎终板缘“鸟嘴样”增生,13例邻近终板侵蚀性破坏,边界模糊,周围硬化.所有患者均无成角畸形及明显神经损害.入院诊断为脊柱肿瘤1例,脊柱结核3例,疑似脊柱结核8例,脊柱感染4例.入院后诊断为“脊柱肿瘤”者直接行“肿瘤椎体”切除植骨内固定术,术后病理诊断为化脓性脊柱骨髓炎;其余15例患者治疗前均行病椎穿刺病理检查,诊断为非特异性脊柱感染,其中10例患者行保守治疗,4例患者因椎间失稳行前路病灶清除植骨、后路内固定术,1例因伴椎旁脓肿行单纯前路病灶清除植骨融合术.均应用敏感或广谱抗生素,手术治疗患者应用2～3周,保守治疗患者应用3～6周.结果:所有患者随访3～18个月,平均12个月.10例保守治疗患者中,6例痊愈;4例遗留腰背部僵硬感,行腰背肌理疗及功能锻炼后均缓解.6例手术患者中,1例误诊为脊柱肿瘤患者术后1.5年X线片显示植骨端骨吸收,患者有腰背部僵硬感,暂予观察;其余5例患者随访时植骨均骨性融合,2例遗留不同程度腰背部僵硬,但均不影响生活.所有患者随访期间无复发.结论:脊柱非特异性感染容易误诊,治疗前行穿刺病理检查可早期确诊,多数患者经保守治疗可治愈,对影响脊柱稳定性者应选择手术治疗.     

Rapid identification of HBB gene mutations by high-resolution melting analysis

ObjectiveThis study was undertaken to identify HBB gene mutation.Design and methodsHerein we evaluated high-resolution melting analysis in the identification of HBB mutations.ResultsWe have successfully established a diagnostic strategy for identifying HBB gene mutations including c.? 78A > G, c.? 79A > G, c.2T > G, c.79_80insT, c.84_85insC, c.123_124insT, c.125_128delTCTT, c.130 G > T, c.170G > A, c.216_217ins A and c.316–197 C > T from wild-type DNA using HRM analysis. The results of HRM analysis were confirmed by direct DNA sequencing.ConclusionsIn summary, we report that HRM analysis is an appealing technique for the identification of HBB mutations. We also believe that HRM can be used as a method for prenatal diagnosis of β-thalassemia.     

非肾病患者肾组织钙敏感受体表达情况

目的本研究旨在了解钙敏感受体(calcium sensing receptor,CaSR)在肾功能正常非肾病患者肾组织中的分布情况,以进一步了解CaSR在肾脏中的表达及可能的影响因素。方法收集遵义医学院第一附属医院非肾病患者需行肾切除的活体组织20例,婴儿尸检肾10例(按诊断和年龄划分为:癌旁肾组织、结石肾组织和婴儿肾组织),运用简化MDRD[1]公式估测肾小球滤过率(estimation glomerularfiltration rate,eGFR),eGFR≥90 ml/min为肾功能正常(normal renal function,NRF)。取患者肾组织进行HE染色,经HE染色证实正常肾组织,然后入选行免疫组织化学染色,显微镜观察CaSR在肾组织中的表达,并对其表达的量进行统计学定量分析,同时选用平均积分光密度(mean of integral optical density,IOD)来分析CaSR在肾组织中的表达情况。结果 HE染色可见细胞核呈深蓝色,胞浆及组织呈深浅不等的红色,且均为正常肾组织。进一步行免疫组织化学染色,结果显示CaSR在肾组织中均有广泛表达,主要表达于肾小管,尤以近端小管上皮细胞明显,远端肾小管、集合管、肾小球、肾血管及肾组织间隙亦可见。结论所有肾组织中均存在CaSR表达,主要表达于肾小管;癌旁肾组织中CaSR与结石肾组织无差异性;但婴儿肾组织中CaSR表达明显高于癌旁肾组织和结石肾组织。     

Simplified PGD of common determinants of haemoglobin Bart’s hydrops fetalis syndrome using multiplex-microsatellite PCR

The high incidence of double-gene deletions in α-thalassaemia increases the risk of having pregnancies with homozygous α⁰-thalassaemia, the cause of the lethal haemoglobin (Hb) Bart’s hydrops fetalis syndrome. Preimplantation genetic diagnosis (PGD) has played an important role in preventing such cases. However, the current gap-PCR based PGD protocol for deletional α-thalassaemia requires specific primer design for each specific deletion. A universal PGD assay applicable to all common deletional determinants of Hb Bart’s hydrops fetalis syndrome has been developed. Microsatellite markers 16PTEL05 and 16PTEL06 within the α-globin gene cluster were co-amplified with a third microsatellite marker outside the affected region in a multiplex-PCR reaction and analysed by capillary electrophoresis. Eight informed couples at risk of having Hb Bart’s hydrops fetalis were recruited in this study and all patients underwent standard procedures associated with IVF. A total of 47 embryos were analysed. Three pregnancies were achieved from three couples, with the births of two healthy babies and one ongoing pregnancy. This work has successfully adapted an earlier protocol and developed a simple and reliable single-cell assay applicable to PGD of Hb Bart’s hydrops fetalis syndrome regardless of type of deletion.Alpha-thalassaemia is one of the most common inheritable disorders worldwide. It is a blood disorder that, in its lethal form caused by deletion of all four copies of the α-globin gene, results in the demise of the affected fetus, a condition referred to as haemoglobin (Hb) Bart’s hydrops fetalis syndrome. Preimplantation genetic diagnosis (PGD) has played an important role in preventing such cases. Current PGD protocols for deletional α-thalassaemia utilize a strategy called gap-PCR, which requires the different assays for different deletion types. We have developed a universal PGD assay applicable to all common deletional determinants of Hb Bart’s hydrops fetalis syndrome based on microsatellite marker analysis. Eight informed couples at risk of having Hb Bart’s hydrops fetalis were recruited in this study and all patients underwent standard procedures associated with IVF. Forty-five embryos were analysed in total. Three pregnancies were achieved from three couples, with the births of two healthy babies and one pregnancy still ongoing. We have successfully adapted our earlier protocol and developed a simple and reliable single cell assay applicable to PGD of Hb Bart’s hydrops fetalis syndrome regardless of the type of deletion.     

细胞壁缺陷型淋病奈瑟菌cppB基因酶切图谱分析

目的探讨细胞壁缺陷对淋病奈瑟菌隐蔽性质粒B(cppB)基因的影响以及细胞壁缺陷型淋病奈瑟菌cppB的变异特点。方法用青霉素诱导淋病奈瑟菌成为细胞壁缺陷型并获得其纯培养物,cppB基因特异性引物PCR检测细胞壁缺陷型纯培养物的cppB基因,并对其cppB基因PCR扩增产物进行限制性核酸内切酶图谱分析。结果细菌型和细胞壁缺陷型均具有cppB基因扩增产物,经过限制性内切酶HindⅢ、HinfⅠ、HpaⅡ和MspⅠ消化和电泳,在5%PAGE凝胶电泳中,呈现出相同的电泳条带。结论淋病奈瑟菌细菌型及其细胞壁缺陷型对cppB基因限制性核酸内切酶(HindⅢ、HinfⅠ、MspⅠ、HpaⅡ)的分析没有发现淋病奈瑟菌L型具有与其亲代细菌型不同的图谱,提示细胞壁缺陷没有导致淋病奈瑟菌的cppB基因发生这些核酸酶切位点中核苷酸序列的改变。