Profilin plays a role in cell elongation, cell shape maintenance, and flowering in Arabidopsis

Profilin (PFN) is an ubiquitous, low-M(r), actin-binding protein involved in the organization of the cytoskeleton of eukaryotes including higher plants. PFNs are encoded by a multigene family in Arabidopsis. We have analyzed in vivo functions of Arabidopsis PFN by generating transgenic plants carrying a 35S-PFN-1 or 35S-antisense PFN-1 transgene. Etiolated seedlings underexpressing PFN (PFN-U) displayed an overall dwarf phenotype with short hypocotyls whose lengths were 20% to 25% that of wild type (WT) at low temperatures. Light-grown PFN-U plants were smaller in stature and flowered early. Compared with equivalent cells in WT, most cells in PFN-U hypocotyls and roots were shorter, but more isodiametric, and microscopic observations of etiolated PFN-U hypocotyls revealed a rough epidermal surface. In contrast, light-grown seedlings overexpressing PFN had longer roots and root hair although etiolated seedlings overexpressing PFN were either the same size or slightly longer than WT seedlings. Transgenic seedlings harboring a PFN-1-GUS transgene directed expression in root and root hair and in a ring of cells at the elongating zone of the root tip. As the seedlings matured PFN-1-GUS was mainly expressed in the vascular bundles of cotyledons and leaves. Our results show that Arabidopsis PFNs play a role in cell elongation, cell shape maintenance, polarized growth of root hair, and unexpectedly, in determination of flowering time.     

Turning regenerative technologies into treatment to repair myocardial injuries

Regenerative therapies including stem cell treatments hold promise to allow curing patients affected by severe cardiac muscle diseases. However, the clinical efficacy of stem cell therapy remains elusive, so far. The two key roadblocks that still need to be overcome are the poor cell engraftment into the injured myocardium and the limited knowledge of the ideal mixture of bioactive factors to be locally delivered for restoring heart function. Thus, therapeutic strategies for cardiac repair are directed to increase the retention and functional integration of transplanted cells in the damaged myocardium or to enhance the endogenous repair mechanisms through cell-free therapies. In this context, biomaterial-based technologies and tissue engineering approaches have the potential to dramatically impact cardiac translational medicine. This review intends to offer some consideration on the cell-based and cell-free cardiac therapies, their limitations and the possible future developments.     

Application of higher order statistics for atrial arrhythmia classification

Atrial fibrillation (AF) and atrial flutter (AFL) are the two common atrial arrhythmia encountered in the clinical practice. In order to diagnose these abnormalities the electrocardiogram (ECG) is widely used. The conventional linear time and frequency domain methods cannot decipher the hidden complexity present in these signals. The ECG is inherently a non-linear, non-stationary and non-Gaussian signal. The non-linear models can provide improved results and capture minute variations present in the time series. Higher order spectra (HOS) is a non-linear dynamical method which is highly rugged to noise. In the present study, the performances of two methods are compared: (i) 3rd order HOS cumulants and (ii) HOS bispectrum. The 3rd order cumulant and bispectrum coefficients are subjected to dimensionality reduction using independent component analysis (ICA) and classified using classification and regression tree (CART), random forest (RF), artificial neural network (ANN) and k-nearest neighbor (KNN) classifiers to select the best classifier. The ICA components of cumulant coefficients have provided the average accuracy, sensitivity, specificity and positive predictive value of 99.50%, 100%, 99.22% and 99.72% respectively using KNN classifier. Similarly, the ICA components of HOS bispectrum coefficients have yielded the average accuracy, sensitivity, specificity and PPV of 97.65%, 98.16%, 98.75% and 99.53% respectively using KNN. So, the ICA performed on the 3rd order HOS cumulants coupled with KNN classifier performed better than the HOS bispectrum method. The proposed methodology is robust and can be used in mass screening of cardiac patients.     

Arginine methylation of the RGG box does not appear to regulate ICP27 import during herpes simplex virus infection

Arginine methylation can regulate protein import and export and can modulate protein interactions. Herpes simplex virus 1 (HSV-1) ICP27 is a shuttling protein involved in viral mRNA export. We previously reported that ICP27 is methylated on three arginines within its RGG box and that arginine methylation regulates ICP27 export and its interaction with SRPK1 and Aly/REF. Here, we report that ICP27 was efficiently imported into the nucleus when hypomethylated as determined by Fluorescence Recovery After Photobleaching (FRAP). Furthermore, coimmunoprecipitation of ICP27 with β-importin was not significantly affected by ICP27 hypomethylation. Thus, ICP27 import does not appear to be regulated by arginine methylation.     

Health Disparity Still Exists in an Economically Well-Developed Society in Asia

Background

The socioeconomic inequalities in child health continue to widen despite improved economy.

Objective

To investigate the correlation between socio-economic factors and health risk behaviors and psychosocial well-being of children in Hong Kong.

Hypothesis

The null hypothesis is that for this particular developed region, there exists little or no correlation between social-economic factors and health risk behaviors and psychosocial well-being of children.

Design

Cross sectional territory wide survey.

Participants

Caregivers of 7,000 children in kindergartens in Hong Kong.

Measuring tools

Youth Risk Behavior Surveillance questionnaire, health-related knowledge and hygienic practice questionnaire, and Children Behavior Checklist (CBCL).

Results

Children were less likely to have somatic complaints and anxiety/depression as reflected by CBCL scores coming from families of higher income, not being recipients of social assistance, with fathers in employment, and with higher parental education. Children with only mother or father as caretakers had lower odds ratios (ORs) 0.71 (95% CI 0.58-0.89) and 0.53 (95% CI 0.33-0.84) respectively to have the habit of eating breakfast, whilst parental education at post-secondary level and higher family income had higher ORs 1.91 (95% CI 1.31-2.78), and 1.63 (95% CI 1.11-2.39). Fathers unemployed, relatives as main caretakers and living in districts with low median household inome incurred higher ORs, as 1.46 (95% CI 1.10-1.94),1.52 (95% CI 1.27-1.83) and 1.17 (95% CI 1.02-1.34) respectively, of watching television over two hours daily, whilst children with parental education at secondary level or above incurred lower OR 0.33 (95% CI 0.24-0.45). Children with parental education at post-secondary level and higher family income had lower ORs of 0.32 (95% CI 0.48-0.97) and 0.52 (95% CI 0.34-0.79) respectively, with regard to exposing to passive smoking, and reversed for those living in districts with lower median household income, lower family income and recipient of CSSA with ORs 1.24 (95% CI 1.06-1.44) and 1.6 (95% CI 1.09-2.37) respectively.

Conclusion

Null hypothesis was not supported. A strong gradient was still found to exist among different socio-economic groups for various health-related behaviors in developed society like Hong Kong.     

Concentration of plasminogen activators and inhibitor in the human endometrium at different phases of the menstrual cycle.

The concentrations of tissue plasminogen activator (t-PA), urokinase plasminogen activator (u-PA) and plasminogen activator inhibitor (PAI-1) have been determined in endometrial curettings obtained from 46 subfertile women during proliferative, early or late secretory phases of the menstrual cycle. t-PA activity and antigen concentrations was significantly higher (P < 0.001) in late secretory endometrium than in proliferative or early secretory endometrium. Higher concentrations of PAI-1 antigen (P < 0.05) were also noted in late secretory phase than in proliferative and early secretory endometrium. However, u-PA concentration was not significantly different and no PAI activity could be demonstrated in the menstrual phases studied. Zymography studies confirmed the presence of both t-PA and u-PA in the endometrium. Ovarian hormonal patterns may therefore influence the activity of plasminogen activators especially of t-PA in the endometrium during various phases of the menstrual cycle.     

Human VEGF165-myoblasts produce concomitant angiogenesis/myogenesis in the regenerative heart

Bioengineering the regenerative heart may provide a novel treatment for heart failure. On May 14, 2002, a 55-year-old man suffering from ischemic myocardial infarction received 25 injections carrying 465 million cGMP-produced pure myoblasts into his myocardium after coronary artery bypass grafting. As on August 28, 2002, his EKG was normal and showed no arrhythmia. His ejection fraction increased by 13%. He no longer experienced shortness of breath and angina as he did before the treatment. Three myogenesis mechanisms were elucidated with 17 human/porcine xenografts using cyclosporine as immunosuppressant. Some myoblasts developed to become cardiomyocytes. Others transferred their nuclei into host cardiomyocytes through natural cell fusion. As yet others formed skeletal myofibers with satellite cells. De novo production of contractile filaments augmented the heart contractility. Human myoblasts transduced with VEGF₁₆₅ gene produced six times more capillaries in porcine myocardium than in placebo. Xenograft rejection was not observed for up to 20 weeks despite cyclosporine discontinuation at 6 weeks. Pros and cons of autografts vs. allografts are compared to guide future development of heart cell therapy. (Mol Cell Biochem 263: 173–178, 2004)