Identification of a new lamin A/C mutation in a chinese family affected with atrioventricular block as the prominent phenotype / 华中科技大学学报（医学）（英德文版）

Even though mutations in LMNA have been reported in patients with typical dilated cardiomyopathy (DCM) and atrioventricular block (AVB) previously, the purpose of this study was to disclose this novel genetic abnormality in one Chinese family with the atypical phenotype of progressive AVB followed by DCM with normal QRS interval. Genome-wide linkage analysis mapped the AVB gene in this family to a marker at chromosome 1q21.2, where the LMNA gene was located. Direct DNA sequence analysis revealed a heterozygous G to A transition at nucleotide 244 in exon 1 of LMNA, which resulted in an E82K mutation. The E82K mutation co-segregated with all affected individuals in the family, and was not present in 200 normal controls. Further clinical evaluation of mutation carriers showed that 5 of 6 AVB patients exhibited mild DCM with a late onset of age in the fourth and fifth decades. Ejection fractions were documented in 5 patients with DCM, but 4 showed a normal value of [Symbol: see text]50%. Echocardiography showed that atrial dilatation occurred earlier than ventricular dilatation in the patients. This study suggests that progressive AVB with normal QRS interval and accompanying DCM at later stages may represent a distinct type of DCM. The molecular mechanism by which the E82K mutation causes AVB as the prominent phenotype in DCM may be a focus of future studies.

Exclusive Gene Mapping in an Congenital Hyperthyroidism Family / 华中科技大学学报(医学版)

Objective Gene linkage would be processed in order to make sure if an autosomal dominant congenital hyperthyroidism family has genetic linking relationship with the known hyperthyroidism disease genes,TSHR or THRB.Methods Microsatellite marked gene linkage was done with the use of three microsatellite markers,D14S74,D3S2338 and D3S1266,whose chromosomal locations were very close to TSHR or THRB gene,and the results were analyzed by Genemapper 3.5 Software.Results LOD scores of the three markers were all less than 1,revealing that there were no linking relationships between TSHR or THRB gene and this hyperthyroidism family,further reflecting this family might have a new disease gene other than TSHR and THRB.Conclusion There might be new disease genes responsible for autosomal dominant congenital hyperthyroidism.

Cloning of KCNE1 gene in long QT syndrome and construction of its eukaryotic expression vector / 医学研究生学报

Objective: To construct the eurokaryotic expression vector of KCNE1 gene and express recombinant KCNE1 in HEK293 cells.Methods:Human KCNE1 gene fragment was amplified from human placenta total RNA by RT-PCR and cloned into the vector of pCR2.1 TOPO by means of T-A cloning.KCNE1 cDNA was obtained from pCR2.1-KCNE1 by restriction enzyme digestion and inserted into the same restriction site of pEGFP-N1.Thus pEGFP-N1-KCNE1 was constructed and transfected into HEK293 cells with Effectene transfection reagent.Results:The eukaryotic expression vector pEGFP-N1-KCNE1 was successfully constructed by gene cloning and recombinant method and expressed in HEK293 cells.Conclusion:The cloning of KCNE1 gene and the construction and expression of its eukaryotic expression vector may shed some light on further functional study of KCNE1 gene.

Decreases Plasma Atrial Natriuretic Peptide in Patients With Salt-sensitive Essential Hypertension and Increase After Benazepril Therapy / 中华高血压杂志

Objective To study the role of atrial natriuretic peptide (ANP) and renin-angiotensin-aldosterone system (RAAS) in the pathogenesis of salt-sensitive (SS) hypertension and mechanism of the hypotensive effect of benazepril and ANP in patients with SS essential hypertension. Methods Sixty-four patients with essential hypertension were divided into SS (n=30) and non-salt-sensitive (NSS, n=34) groups by modified Sulliran's method. Plasma ANP, angiotensin Ⅱ (AⅡ) and aldosterone (ALD) were determined before and during the period of salt loading test. Thirty healthy subjects as controls were also enrolled. A self-comparative study of benazepril with the placebo was performed in SS group. Before and after the placebo and benazepril therapy, blood pressure (BP) and plasma ANP were determined. Results (1)Basal plasma ANP level in the SS group was significantly lower than that in the NSS group. Basal plasma ANP level in the NSS group was also significantly lower than that in the control group [(110.28±15.40) pmol/L vs NSS (145.52±26.53) pmol/L and control (197.74±26.20) pmol/L]. Plasma ANP in both SS and NSS groups [(133.56±34.03) pmol/L and (169.20±35.91) pmol/L respectively, both P<0.05 vs control]. Percentage of increase of plasma ANP in SS and NSS groups was of no difference (P>0.05) . (2) No significant difference of basal plasma AⅡ and ALD levels were found between SS and NSS groups (P>0.05). There were no significant changes of plasma AⅡ and ALD during salt loading in both SS and NSS groups ( both P>0.05). (3) After the benazepril treatment, plasma ANP was increased significantly [(146.74±31.86) pmol/L , P<0.01]; both systolic and diastolic BP were reduced significantly in SS group. (4) Basal plasma ANP level was negatively correlated with the magnitude of increase of mean arterial pressure (MAP) by salt loading (b=-0.06, P<0.05). Conclusion Deficiency of circulating endogenous ANP may play an important role in the pathogenesis of SS hypertension. Benazepril could reduce BP and increase plasma ANP significantly in patients with SS hypertension.