福建畲族人群15个短串联重复序列的遗传多态性及法医学应用

目的对福建畲族群体15个短串联重复序列等位基因遗传多态性进行分析,探讨其种族特异性及其在法医学个体识别和亲权鉴定的中的应用。方法荧光标记15个短串联重复序列(STR)位点和一个性别位点并进行PCR复合扩增,用ABI遗传分析仪以毛细管电泳技术对100例福建畲族无血缘关系健康个体PCR产物进行电泳分离基因,并以分析软件进行基因分型。结果共检出126个等位基因,基因频率范围在0.0050～0.5550。15个STR基因座的基因型分布均符合Hardy-Weinberg平衡。15个STR位点的HET在0.6300～0.8900之间,DP在0.7680～0.9590之间,EPP在0.3280～0.7750之间,PIC在0.5200～0.8600之间。累积DP和EPP分别达到0.99999999和0.99999288。结论15个STR位点均有较高的遗传多态性,并有丰富的信息含量,适合作为福建畲族地区的遗传标记,可用于个体识别和亲权鉴定。     

女性泌尿生殖道解脲支原体基因分型的研究

解脲支原体主要存在于人类泌尿生殖道及生殖腺中,是引起泌尿生殖系统感染及男女不孕不育的主要病原体,也是性传播的常见病原体,对这种条件致病病原体进一步分群分型是判断感染与携带状态的关键,故解脲支原体的基因分型是目前研究的热点.该文对解脲支原体在女性泌尿生殖道的致病机理、基因分型和分型的方法及其基因分型与临床流行病学之间关系的研究进展进行综述,探讨解脲支原体的基因分型在女性泌尿生殖道感染发病机制研究中的重要作用.     

大肠埃希菌耐药性变化及其DNA多态性分析

目的了解某院2001-2005年大肠埃希菌耐药性变化趋势并对其DNA多态性进行分析。方法采用VITEK全自动微生物鉴定仪对大肠埃希菌临床分离株进行鉴定；Kirby-bauer（K-B）法进行药敏试验；对分离菌株中的10株敏感株和10株耐药株进行随机引物聚合酶链反应（PCR）扩增。结果大肠埃希菌对除亚胺培南、阿莫西林／克拉维酸以外的其他抗菌药物敏感率均呈下降趋势。10株敏感菌呈9种基因型；10株耐药菌仅呈3种基因型，其中6株菌为同一谱型。结论大肠埃希菌对常用抗菌药物耐药率高，耐药范围广，并且其耐药表型与其基因型之间具有一定的相关性。     

AT1R、ACE基因多态性与东乡族原发性高血压的关系及其对降压药疗效的影响

目的：探讨血管紧张素转换酶（ACE）、血管紧张素Ⅱ（AngⅡ）Ⅰ型受体（ATIR）基因多态性与甘肃东乡族原发性高血压（EH）的关系。对不同基因型患者使用AT1R拮抗剂治疗，观察其疗效。方法：应用聚和酶链反应（PCR）方法检测汉族健康131例、东乡族健康102例、汉族EH198例、东乡族EH115例的AT1RA／C、ACE I／D基因多态性。随机选取60名EH患者，按其基因型分成AA和AC（AA、AC为基因型）两组，使用缬沙坦治疗8周，比较治疗前后血压变化。结果：ACE基因Ⅱ型在汉族EH组明显高于东乡族EH组（P〈0．05），ID基因型在东乡族EH组明显高于汉族EH组（P〈0．01）；AT1R基因AC型汉族EH组明显高于东乡族EH组（P〈0．05）；AA型在东乡族EH组明显高于汉族EH组（P〈0．05）。使用缬沙坦治疗8周，各基因型在治疗后患者血压均下降显著（P〈0．05）。不同基因型之间治疗后比较，降压效果无差异。结论：AT1R基因AA型和ACE基因ID型与东乡族EH有关；ACE基因Ⅱ型和AT1R基因AC型与汉族EH有关，C和D等位基因与汉族和东乡族EH无关。使用缬沙坦对不同基因型患者进行药物治疗，降压疗效相同，说明降压疗效与基因型无关。     

Rh genotyping: avoiding false-negative and false-positive results among individuals of African ancestry

High homology, variant alleles, and silent alleles have made the development of completely reliable genotyping assays for the RHD and RHC alleles difficult. An RHD pseudogene (RHDPsi) possessing a 37-bp insertion within exon 4 is common among serologically RhD-negative individuals of African descent and generates false-positive results in previously reported RhD genotyping assays. Genotyping RhC is problematic due to exon 2 homology between RHD and RHC; however, an RHC-specific 109-bp insertion within intron 2 has been reported useful for genotyping. Primers flanking the exon 4 insertion point were used for detection of RHD and RHDPsi among a total of 231 serotyped individuals: 134 African American, 85 Caucasian, and 12 RhD serotype-negative/genotype-positive, D-sensitized women. Primers flanking the RHC-specific intron 2 insertion were used to genotype 282 serotyped individuals (128 African American, 154 Caucasian) and were compared to RHC genotyping using the exon 1 RhC-specific nt48 cytosine polymorphism. Complete correlation was observed between genotyping with the RHDPsi primer pair and serotyping among 219 individuals and 10/12 previous RHD false-positive genotyping results were resolved. RHDPsi was detected in 19% (n = 4/21) of RhD seronegative African Americans and 4.4% (n = 5/113) of RhD seropositive African Americans. When using the 109-bp intron 2 insertion for genotyping of RHC, a 23.9% (n = 11/46) false-negative rate was observed among African American RhCc serotyped heterozygotes. Utilization of the exon 1 nt48 cytosine for indirect genotyping of RHC yielded a 7.2% (n = 4/55) and 56.3% (n = 45/80) false-positive rate among Rhcc Caucasians and African Americans, respectively. We conclude that these additional reactions, though not sufficient alone, can be useful supplements to existing Rh genotyping assays.     

Clonal variability among oral Candida albicans assessed by allozyme electrophoresis analysis

A total of 49 Candida albicans strains were isolated from the saliva of 11 healthy children in Piracicaba, Brazil and were analyzed according to their alloenzymatic patterns. Among eight loci assayed, seven were polymorphic and allowed to determine allelic and genotype frequencies, in order to establish the genetic variables for this fungal population. Some children showed just one genetic type, whereas other harbored two or more clones of such yeast, in a multiclonal manner of colonization by C. albicans.     

Circulating HO-1 levels are not associated with plasma sFLT-1 and GTn HMOX1 polymorphism in preeclampsia

Objectives: We aimed to assess the plasma HO-1 level and its interrelationship with the plasma sFLT-1 level in preeclamptic and healthy pregnant women with different variants of microsatellite polymorphism (GTn) located in the promoter region of the HMOX-1 gene.

Methods: HO-1 and sFLT-1 were measured by ELISA. HMOX1 genotyping was performed using fragment analysis.

Results: We found similar and higher levels of plasma HO-1 and sFLT-1, respectively, in preeclampsia. Similar genotypes and alleles frequencies were found in both groups and the absence of modulation of HO-1 levels by genotypes were observed.

Conclusion: The plasma HO-1 levels are not increased in preeclampsia women and neither related to sFLT-1 levels and GT_n polymorphism.     

Distribution of fimA genotypes of Porphyromonas gingivalis in subjects with various periodontal conditions

Fimbria encoded by the gene fimA is considered one of the main factors in the colonization of the oral cavity by Porphyromonas gingivalis. Allelic variation in fimA led to the classification of strains of P. gingivalis into six genotypes. The occurrence of P. gingivalis was determined by polymerase chain reaction using 16S rRNA primers in 302 subgingival samples obtained from 102 Brazilian subjects exhibiting different periodontal conditions. Distribution of fimA genotypes was assessed in 146 P. gingivalis positive samples by polymerase chain reaction using primers pairs homologous to the different fimA genes. P. gingivalis was detected in 51 of 57 (89.4%) patients with periodontal attachment loss, in six of 20 gingivitis patients (30.0%) and in two of 25 (8.0%) subjects with a healthy periodontium. Variant type II was the only type detected in 53 sites (39.3%), distributed among 19 periodontitis patients (37.3%) and in one patient with no periodontal destruction. Type Ib was the second most prevalent genotype in periodontitis patients (19.6%). Genotype V was not detected in the studied population. Type IV was the most commonly type found among gingivitis patients, either alone or in combination with other genotypes. Multiple genotypes were detected in nine sites (6.1%). A fimA genotype was not identified in 26 sites (17.8%) of 146 sites positive for P. gingivalis, suggesting that other alleles of fimA not yet sequenced may be prevalent in this population. These data demonstrated that P. gingivalis type II strains followed by type Ib are more prevalent in periodontitis patients from a multiracial population in Brazil, suggesting an increased pathogenic potential of these types.     

Real-time PCR genotyping of human platelet alloantigens HPA-1, HPA-2, HPA-3 and HPA-5 is superior to the standard PCR-SSP method

Genotyping of the human platelet alloantigens (HPA) is useful for the diagnosis and therapy of the patients with alloimmune thrombocytopenic syndromes, such as post-transfusion refractoriness to platelets, post-transfusion thrombocytopenic purpura and foetomaternal alloimmune thrombocytopenia. We have developed, optimized and validated a new method for simultaneous genotyping of HPAs - HPA-1, HPA-2, HPA-3 and HPA-5 - by using the real-time polymerase chain reaction (PCR) based on TaqMan technology. Its performances were compared to those of the standard PCR-sequence-specific primers (SSP) method by testing 120 DNA samples. Several discrepancies between the two methods have been observed, especially in the HPA-3 genotyping. Evidently, the PCR-SSP method produced several false positive results due to its technical drawbacks. Based on our comparison, we believe that the new real-time TaqMan PCR assay for the HPA-1, HPA-2, HPA-3 and HPA-5 genotyping is faster, more reliable and reproducible, compared to the standard PCR-SSP.     

Gene frequencies of the HPA-15 (Gov) platelet alloantigen system in Brazilians

The HPA-15 (Gov) alloantigen is a biallelic co-dominant system on human platelets, and its allele HPA-15a and HPA-15b differ by an A-->C single nucleotide polymorphism at nucleotide 2108 of the coding sequence resulting in a Tyr682Ser substitution in the mature CD109 glycoprotein. Employing the polymerase chain reaction-restriction fragment length polymorphism technique, we determined the HPA-15 gene frequencies among 276 subjects of distinct Brazilian ethnic groups including, 15 Caucasians, 15 African Brazilians, 15 Orientals, 106 Amazon Xikrin Indians, 31 Amazon Gavioes Indians and 94 blood donors. The calculated HPA-15a and HPA-15b allele frequencies found in Caucasians (0.53/0.47), African Brazilians (0.57/0.43), Orientals (0.57/0.43) and Brazilian blood donors (0.52/0.48) did not differ significantly. However, the HPA-15a and HPA-15b gene frequencies of Xikrin Indians (0.78/0.22) were significantly different from that of all other groups (P < 0.01). The HPA-15a/a, HPA-15a/b and HPA-15b/b genotype frequencies observed in Gavioes Indians were significantly different from those seen in African Brazilians (P = 0.04) and blood donors (P = 0.017). The present data showed that the distribution of the HPA-15 (Gov) system alleles observed among the Brazilian population is quite similar to the distributions already reported among Asian, Canadian and European populations. Moreover, the data indicated differences in the frequency of the HPA-15 system between Amazon Indians and other distinct Brazilian ethnic groups suggesting that Amerindians would be at higher risk of HPA-15 alloimmunization in the need of receiving blood components collected from blood donors of other ethnic groups.