Analysis of two propositas with inherited hypodysfibrinogenemia / 中华检验医学杂志

Objective:To analyze the phenotype and genotype of two propositi with inherited hypodysfibrinogenaemia caused by compound heterozygous mutations, and investigate the molecular mechanism.Metheds:Two propositi and their family members(7 person in 3 generations and 10 person in 3 generations,respectively) were investigated. The activity of plasma fibrinogen (Fg:C) and thrombin time (TT) were analyzed by coagulation method, the antigen of plasma fibrinogen (Fg:Ag) was detected by immunoturbidimetry. All of the exons and flanking sequences of FGA,FGB,FGG of two propositi were amplified by PCR, followed by direct sequencing. The ClustalX-2, 1-win software was used to analyze the conservatism of mutated gene locus. PROVEAN and Mutation Taster were applied to analyze the pathogenicity of mutated amino acid. The changes of the protein spatial structure and intermolecular interaction were analyzed by Pymol.Results:Fg:C and Fg:Ag of proposita A and B were both significantly decreased (0.74 and 0.78 g/L, 0.96 and 0.94 g/L, respectively). Gene analysis revealed that proposita A and B both carried a heterozygous mutation c.2185G>A(p.AαGlu710Lys) in exon 6 of FGA. Furthermore, proposita A also carried a heterozygous mutation c.701G>T(p.γTrp208Leu) in exon 7 of FGG, and proposita B carried a heterozygous mutation c.1015A>C(p.γSer313Arg) in exon 8 of FGG. Phylogenetic analysis suggested that p.AαGlu710,p.γTrp208 and p.γSer313 were highly conserved among homologous species. All variants were predicted to be deleterious by two online bioinformatic softwares. The protein model analysis indicated that protein spatial structure and intermolecular hydrogen bonds were changed by these variants, which destroyed the stability of Fg.Conclusion:The compound heterozygous mutations of p.AαGlu710Lys and p.γTrp208Leu,p.AαGlu710Lys and p.γSer313Arg might account for the hypodysfibrinogenemia in two propositi.

Identification of compound heterozygous variants of F12 gene in a pedigree affected with inherited coagulation factor XII deficiency / 中华医学遗传学杂志

OBJECTIVE@#To explore the molecular pathogenesis for a pedigree affected with hereditary coagulation factor XII (FXII) deficiency.@*METHODS@#Potential variant of the F12 gene was analyzed by PCR and Sanger sequencing. Expression plasmids were constructed by site-directed mutagenesis based on the wild-type and transiently transfected into 293T cells. FXII:C and FXII:Ag of the expression products were determined in the supernatant and cell lysate. Western blotting was used to verify the identify of the protein.@*RESULTS@#Gene sequencing revealed that the proband has carried 46TT genetype and heterozygous p.Glu502Lys variants in exon 13, and a heterozygous p.Gly542Ser variant in exon 14 of the F12 gene. Transfection experiment suggested that the FXII:C and FXII:Ag of p.Glu502Lys variant in the supernatant were 28% and 24%, compared with the wild-type (100%) and FXII:Ag of cell lysates was 39% compared to the wild-type (100%). The FXII:C and FXII:Ag of p. Gly542Ser variant in the supernatant were 32% and 17% and the FXII:Ag of cell lysates was 59%.@*CONCLUSION@#The 46TT genetype, p.Glu502Lys and p.Gly542Ser variants of the F12 gene probably underlie the low FXII level in the proband. As shown by in vitro experiment, the p.Glu502Lys and p.Gly542Ser variants can both inhibit the synthesis and secrection of the FXII protein.

Nutritional status of vitamin D and its influencing factors in preterm infants at the early stage after birth / 中华临床营养杂志

Objective To investigate the nutritional status of vitamin D in preterm infants after birth and further explore its possible influencing factors, so as to guide clinical vitamin D therapy and to screen the preterm infants who are at high risk of vitamin D deficiency.Methods Retrospective analysis was conducted in the neonatal department of our hospital from April 21st, 2014 to February 5th, 2016.The serum 25(OH)D level in preterm infants were measured 2 weeks after birth.Data including gender, season of birth, time to initiation of breastfeeding were collected.According to the 25(OH)D levels[25(OH)D≤37.5 nmol/L, 37.5 nmol/L≤50.0 nmol/L, and 25(OH)D>50.0 nmol/L], all the preterm infants were divided into three groups: vitamin D deficiency, insufficiency, and sufficiency groups.The influencing factors of vitamin D in preterm infants were screened by using statistical method.Results The mean 25(OH)D level of 172 preterm infants was (43.1±16.7)nmol/L.In vitamin D deficient, insufficient, and sufficient groups, there were 68 (40％), 50 (29％) and 54(31％) cases of preterm babies, respectively.The mean values of 25(OH)D in these three groups were (27.8±16.7)nmol/L, (42.4±3.4)nmol/L, and (63.0±11.7)nmol/L, respectively.Only the season of birth had significant difference among three groups (P=0.013): 44.2％ of the preterm infants born in winter had vitamin D deficiency, which was higher than those in spring (41.7％), summer(33.3％), and autumn (38.1％);44.2％ of the preterm infants born in winter had vitamin D insufficiency, which was much higher than those in spring (30.6％), summer (25.1％), and autumn (19.0％);furthermore, only 11.6％ of the preterm infants born in the winter had vitamin D sufficiency, which was much lower than those in spring (27.8％), summer (41.2％), and autumn (42.9％) (OR=4.655, 95％ CI=1.716-12.627, P=0.003).Conclusion Vitamin D deficiency in preterm infants 2 weeks after birth is prevalent, and winter birth is a risk factor of vitamin D deficiency and insufficiency in preterm infants.

Prevalence and plasmid characterization of the qnrD determinant in Morganella morganii isolates / 中华微生物学和免疫学杂志

Objective To investigate the prevalence and plasmid size of qnrD determinant in Morganella morganii (M.morganii) isolates.Methods A total of 100 non-duplicated M.morganii clinical isolates were collected from inpatients.Standard ager dilution method was used to determine the minimum inhibitory concentrations (MICs) of fluoroquinolones against M.morganii isolates.PCR were performed to detect plasmid-mediated quinolone resistance determinants (PMQRs) in M.morganii isolates and the prevalence of extended-spectrum β-lactamase (ESBL) genes and AmpC β-lactamase genes in PMQRs-positive M.morganii strains.The homology analysis among qnrD-positive M.morganii strains were conducted by using pulsed-field gel electrophoresis (PFGE).The location of qnrD gene and the size of plasmid carrying it were determined by southern hybridization.The transferability of qnrD gene was determined by conjugation experiment.Results Thirty out of 100 M.morganii isolates (30％) were found carrying PMQRs including 17 qnrD-positive strains,14 aac (6')-Ib-cr-positive strains and 5 qepA-positive strains.PCR and sequencing confirmed that thirty PMQRs-positive isolates carried blaDHA-1.Among them,six isolates were positive for ESBLs genes (four for blaCTX-M-14,one for blaCTX-M-3 and one for blaCTX-M-24) and four isolates were positive for blaTEM-1.Almost all PMQRs-positive M.morganii isolates showed reduced susceptibility to fluoroquinolones.Moreover,seventeen qnrD-positive M.morganii isolates harbored blaDHA-1 including five (29.4％) harboring aac(6')-Ib-cr gene,four (23.5％) harboring blaCTX-M-14,two (11.8％) harboring blaTEM-1 and one harboring aac(6')-Ib-cr gene,blaCTX-M-14 and blaDHA-1.PFGE analysis showed that the 17 qnrD-positive M.morganii isolates were divergent from each other and not clone-related.Southern hybridization analysis showed that qnrD genes of all M.morganiiis isolates were mainly located in a 2.7 kb plasmid,but only a few of them were located in a size of 5.1 kb plasmid.M.morganiiis isolates failed to transfer qnrD gene to E.coli EC600 through conjugation.Conclusion PMQRs were widely distributed in M.morganiiis isolates.qnrD gene was the predominant determinants with a high prevalence rate of 17.0％,followed by aac(6')-Ib-cr gene.qnrD gene was located on a non-conjugative plasmid of approximately 2.7 kb or 5.1 kb.One qnrD-positive M.morganii isolate carrying aac(6')-Ib-cr gene,blaCTX-M-14 and blaDHA-1 was detected.

Study on the resistant genes and virulence gene of vancomycin-resistant Enterococci / 中华微生物学和免疫学杂志

Objective To study the vancomycin-resistant genes and the virulence factors genes in vancomycin-resistant Enterococci (VRE),and to analyze the drug-resistance character and epidemic characteristics of VRE strains and provide the basis for clincal selection of drugs and infection control.Methods VRE were screened by agar dilution sieving plate (ADSP) containing 6 μg/ml of vancomycin,drug resistance of VRE to other common antibiotics were detected by VITEK-60 automatic microbial analyzer.The gene types and virulence factor genes of VRE were determined by PCR.And the genetic relationships among VRE were determined by multilocus sequence typing.Results Seven vancomycin-resistant Enterococcus faecium strains were found in 360 enterococcus strains.All the VRE strains exhibited high-level vancomycin resistance ; some of them were medium or senstive to teicoplanin.They all carried vanA gene and esp gene and one of them carried 4 kinds of virulence factor genes.The ST type of the 7 VRE strains were diffused distribution.Conclusion We found vanB phenotype vanA genotype vancomycin-resistant Enterococcus faecium isolates in Wenzhou; these VRE strains were multidrug resistance and carried various virulence factor genes.Linezolid could be used as a recommend drug for treatment of VRE infection.The protection of antibiotics sensitivity should be strengthened.