Comparison between left atrial features in well-controlled hypertensive patients and normal subjects assessed by three-dimensional speckle tracking echocardiography.

BACKGROUND: Three-dimensional speckle tracking echocardiography (3D-STE) has a major advantage in the improvement of accuracy in the evaluation of cardiac chamber volume without any geometrical assumption. Thus, the aim of this study was to use 3D-STE to elucidate the features of left atrial (LA) volume and function that are altered by hypertension (HTN) by comparing well-controlled HTN patients with normal subjects. METHODS: Conventional echocardiographic parameters and LA phasic volume and function were measured from apical view by 3D-STE in 40 patients with well-controlled HTN [systolic blood pressure (BP) <140 and diastolic BP <90mmHg for more than one year] and 40 normotensive subjects. RESULTS: The passive LA emptying function (EF) in the patients with well-controlled HTN significantly decreased (16±7% vs. 22±8%, p=0.0013) and the active LAEF in patients with well-controlled HTN significantly increased (35±10% vs. 30±9%, p=0.029) compared with the values in normotensive subjects. Multivariate logistic regression analysis revealed that E/e' was an independent determinant of well-controlled HTN. The maximum LA volume index was correlated with elevated E/e' (r=0.30, p=0.0064), whereas the maximum LA volume index was not correlated with LV mass index or systolic BP. This change was independent of age. CONCLUSIONS: These results suggest that LV diastolic dysfunction occurs before structural changes of left atrium and left ventricle even in patients with well-controlled HTN.

RNA interference of the Arabidopsis putative transcription factor TCP16 gene results in abortion of early pollen development.

Pollen development is a fundamental and essential biological process in seed plants. Pollen mother cells generated in anthers undergo meiosis, which gives rise to haploid microspores. The haploid cells then develop into mature pollen grains through two mitotic cell divisions. Although several sporophytic and gametophytic mutations affecting male gametogenesis have been identified and analyzed, little is known about the underlying molecular mechanism. In this study, we investigated the function of the TCP16 gene, which encodes a putative transcription factor. Expression analysis of the promoter::GUS fusion gene revealed that TCP16 transcription occurred predominantly in developing microspores. GUS expression began at the tetrad stage and markedly increased in an early unicellular stage. Transgenic plants harboring a TCP16 RNA interference (RNAi) construct generated equal amounts of normal and abnormal pollen grains. The abnormal pollen grains exhibited morphological abnormality and degeneration of genomic DNA. The defective phenotype of the RNAi plants was first detectable at the middle of the unicellular stage. Our results therefore suggest that TCP16, a putative transcription factor, plays a crucial role in early processes in pollen development.

Prospective study on early virologic response to treatment with interferon alpha-2b plus ribavirin in patients with chronic hepatitis C genotype 1b.

To evaluate the predictive value of early virologic response (EVR) of achieving a sustained virologic response (SVR), an open, prospective trial including 42 patients with chronic hepatitis C genotype 1b was performed with directly observed 24-week treatment with interferon alpha-2b plus ribavirin. We assessed the predictive values of EVR at days 3, 7, 14, and weeks 4, 8, and 12 of the SVR. The SVR in an intention-to-treat analysis was 19.0%. Patients who reached SVR presented a significantly faster reduction in plasma viral load. Stepwise multiple logistic regression analysis of the factors (gender, age, IFN dosage, ribavirin dosage, HCV RNA, ISDR, and loss of HCV RNA at week 4) revealed that loss of HCV RNA at week 4 was the only independent variable of treatment outcome (P=0.0039). A viral load at treatment day 3 above 100kIU/ml, at day 7 above 50kIU/ml, and at day 14 above 10kIU/ml was 100% predictive for virologic non-response in all except 1 patient. The cutoff levels for HCV RNA at days 3 and 14 of treatment were associated with an algorithm of the failure to detect HCV RNA after 12 weeks of treatment. In conclusions, a very early virologic response assessment could be useful for prediction of later outcome of combination therapy in chronic hepatitis C genotype 1b.