Familiar hypertrophic cardiomyopathy caused by a IVS15-1G > A mutation in cardiac myosin-binding protein C gene / 中华心血管病杂志

<p><b>OBJECTIVE</b>To detect the disease-causing gene mutation of hypertrophic cardiomyopathy (HCM) in a Chinese family and to analyze the correlation of the genotype and the phenotype.</p><p><b>METHODS</b>One family affected with HCM was studied. The clinical data including symptom, physical examination, echocardiography and electrocardiography were collected. The full encoding exons and flanking sequences of beta-myosin heavy chain gene (MYH7) and cardiac myosin-binding protein C gene (MYBPC3) were amplified with PCR and the products were sequenced.</p><p><b>RESULTS</b>A G8887A mutation, which is an acceptor splicing site of intron 15 (IVS15-1G > A) in MYBPC3 (gi: Y10129) was identified in 6 out of 11 family members. Three mutation carriers developed HCM at 48 - 75 years old with mild chest pain, chest distress and asymmetric septal hypertrophy (13 - 14 mm) and remaining mutation carriers are free of HCM. No mutation was identified in MYH7 gene.</p><p><b>CONCLUSION</b>HCM caused by the IVS15-1G > A mutation is a benign phenotype. It is helpful to screen MYBPC3 gene mutation in late-onset HCM patients with mild symptoms.</p>

Centrifugal force stretcher a new of in vitro mechanical cell stimulator / 生理学报

A number of mechanical cell stimulators have been used to study the effect of mechanical stimulation on cells in vitro. But the efficiency of these devices is not fully desirable. We recently developed a new device for mechanical cell stimulation, the centrifugal force stretcher, and compared its efficacy with that of the traditional Flexercell Strain Unit. When the mechanical stretcher circumrotates with certain speed, cardiac myocytes attached on the plate are stretched and elongated by centrifugal force. Neonatal rat cardiac myocytes were isolated by enzymatic dissociation from the hearts of 3~5 d old Sprague Dawley rats, and were mechanically stimulated by traditional 20% stretch and 180 r/min centrifugal force for 12 and 24 h. The effects of mechanical stimulation on the hypertrophic response of neonatal rat cardiac myocytes and production of angiotensin II (Ang II) were examined. Compared with the non-stretch group, the radioactivity of (3)H-leucine incorporated into the stretch-stimulated cardiac myocytes in the centrifugal force stretch group was significantly higher [(1295.17+/-51.19) vs (1122.67+/-51.63) in 12 h; (1447.5+/-35.96) vs (1210.67+/-90.92) in 24 h, P<0.05]. Ang II was also dramatically increased by 128% in 12 h (P<0.05) and 139% in 24 h (P<0.01). After the myocytes was stretched for 24 h, the LDH level in the medium in the Flexercell Strain Unit group was significantly higher than that in the centrifugal force group [(14.5+/-8.7) U/L vs (7.8+/-4.3) U/L, P<0.05]. The centrifugal force stretcher is a new and improved mechanical cell stimulator with the same effects on the protein synthesis and Ang II secretion of the cardiac myocytes, and the damage to the cells bronght by this stimulator is relatively slighter in comparison with the Flexercell Strain Unit.