Ohjective To investigate the associations between the Arg389Gly polymorphism of the β_1-adrenergiecreceptor gene (ADRB1) and vasovagal syncope (VVS) in Chinese children. Methods Genotype of ADRB1 was determined by polymerase chain reaction-restriction fragment length pelymorphism analysis. Case-control studies and quantitative trait analysis were carried out by comparing between carriers (one or two copies of the Gly389 allele) and non-carriers (Arg389 genotype) of the ADRBI in 54 patients with unexplained syncope and in 54 healthy control subjects. Patients were subdivided into two groups according to head up tilt test (HUTT) : positive HUTT, known as VVS group and negative HUTT group. Distribution of Arg389Gly genetype in VVS group and the relationship to three clinical patterns were also analyzed. Results An allele frequency of Arg389 was 73.15% and Gly389 was 26.85% in healthy subjects. Higher Gly389 allele frequency was found in VVS group (n = 30) than that in negative HUTT group (33.33% vs. 14.58%, P < 0.05). In VVS group, the frequencies of the Gly389 allele in cardioinhibitory pattern (n = 6), mixed pattern (n = 9) and vasodepressor pattern (n = 15) was 66.67%, 33.3% and 23.33%, respectively, which had significant differences between the cardioinhibitory pattern from any of the other two patterns (both P < 0.05). Conclusions An association of positive HUTT with a single nucleotide pelymorphism of Gly to Arg switch at position 389 of the ADRB1 was found. This polymorphism may contribute to susceptibility to VVS.

OBJECTIVE: To determine whether an optimal blood suppression inversion time (BSP TI) can boost arterial visibility and whether the optimal BSP TI is related to breathing rate (BR) and heart rate (HR) for hypertension subjects in spatial labeling with multiple inversion pulses (SLEEK). MATERIALS AND METHODS: This prospective study included 10 volunteers and 93 consecutive hypertension patients who had undergone SLEEK at 1.5T MRI system. Firstly, suitable BSP TIs for displaying clearly renal artery were determined in 10 volunteers. Secondly, non-contrast enhanced magnetic resonance angiography with the suitable BSP TIs were performed on those hypertension patients. Then, renal artery was evaluated and an optimal BSP TI to increase arterial visibility was determined for each patient. Patients' BRs and HRs were recorded and their relationships with the optimal BSP TI were analyzed. RESULTS: The optimal BSP TI was negatively correlated with BR (r1 = -0.536, P1 < 0.001; and r2 = -0.535, P2 < 0.001) and HR (r1 = -0.432, P1 = 0.001; and r2 = -0.419, P2 = 0.001) for 2 readers (kappa = 0.93). For improving renal arterial visibility, BSP TI = 800 ms could be applied as the optimal BSP TI when the 95% confidence interval were 17-19/min (BR1) and 74-82 bpm (HR1) for reader#1 and 17-19/min (BR2) and 74-83 bpm (HR2) for reader#2; BSP TI = 1100 ms while 14-15/min (BR1, 2) and 71-76 bpm (HR1, 2) for both readers; and BSP TI = 1400 ms when 13-16/min (BR1) and 63-68 bpm (HR1) for reader#1 and 14-15/min (BR2) and 64-70 bpm (HR2) for reader#2. CONCLUSION: In SLEEK, BSP TI is affected by patients' BRs and HRs. Adopting the optimal BSP TI based on BR and HR can improve the renal arterial visibility and consequently the working efficiency.
Adult ; Female ; *Heart Rate ; Humans ; Hypertension/pathology ; Kidney/*blood supply ; Magnetic Resonance Angiography/*methods ; Male ; Middle Aged ; Prospective Studies ; Renal Artery/*physiology ; *Respiratory Rate

This study aims to gain insight into the DNA-specific recognition mechanism of c-Myb transcription factor during the regulation of cell early differentiation and proliferation. Therefore, we chose the chicken myeloid gene, mitochondrial import protein 1 (mim-1), as a target to study the binding specificity between potential dual-Myb-binding sites. The c-Myb-binding site in mim-1 is a pseudo-palindromic sequence AACGGTT, which contains two AACNG consensuses. Simulation studies in different biological scenarios revealed that c-Myb binding with mim-1 in the forward strand (complex F) ismore stable than that inthereverse strand (complex R). The principal component analysis (PCA) dynamics trajectory analyses suggested an opening motion of the recognition helices of R2 and R3 (R2R3), resulting in the dissociation of DNA from c-Myb in complex R at 330 K, triggered by the reduced electrostatic potential on the surface of R2R3. Furthermore, the DNA confirmation and hydrogen-bond interaction analyses indicated that the major groove width of DNA increased in complex R, which affected on the hydrogen-bond formation ability between R2R3 and DNA, and directly resulted in the dissociation of DNA from R2R3. The steered molecular dynamics (SMD) simulation studies also suggested that the electrostatic potential, major groove width, and hydrogen bonds made major contribution to the DNA‍-specific recognition. In vitro trials confirmed the simulation results that c-Myb specifically bound to mim-1 in the forward strand. This study indicates that the three-dimensional (3D) structure features play an important role in the DNA-specific recognition mechanism by c-Myb besides the AACNG consensuses, which is beneficial to understanding the cell early differentiation and proliferation regulated by c-Myb, as well as the prediction of novel c-Myb-binding motifs in tumorigenesis.
Molecular Dynamics Simulation ; Consensus ; DNA ; Hydrogen