Vitamin C enhances the in vitro development of porcine pre-implantation embryos by reducing oxidative stress

Vitamin C (Vc) is a natural compound supplemented to culture media to guarantee the appropriate reactive oxygen species (ROS) level, as well as protect cells from oxidative damage and apoptosis. The current study was conducted to determine the effects of Vc (0, 2.5, 5, 10, 20 and 40 μg/ml) on the ROS production, developmental ability and quality of in vitro produced porcine parthenotes. The results show that: (i) the ROS levels in the embryos significantly decrease in the Vc-treated groups compared with the control (p < 0.05), (ii) the rates of blastocyst formation and total cell numbers in each blastocyst are significantly higher in the Vc-treated groups than in the control (p < 0.05); the optimum concentration of Vc is 20 μg/ml, (iii) the relative expression of Bcl-xL significantly increases and that of Bax is downregulated after Vc treatment. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling analysis indicates that the ratio of apoptotic cells in the blastocyst is also significantly lower in Vc-treated groups (p < 0.05) and (iv) Vc treatment can also increase the expression of the Nanog gene in porcine embryos, with a fivefold increase in 20 μg/ml Vc treatment compared with the control (p < 0.05). Therefore, Vc improves the development of porcine embryos by reducing the ROS levels. Vc addition in PZM-3 medium can decrease the number of apoptotic cells and increase the cell numbers in blastocysts to produce high-quality porcine embryos in vitro.

Phosphorylation state-dependent interactions of hepadnavirus core protein with host factors

Dynamic phosphorylation and dephosphorylation of the hepadnavirus core protein C-terminal domain (CTD) are required for multiple steps of the viral life cycle. It remains unknown how the CTD phosphorylation state may modulate core protein functions but phosphorylation state-dependent viral or host interactions may play a role. In an attempt to identify host factors that may interact differentially with the core protein depending on its CTD phosphorylation state, pulldown assays were performed using the CTD of the duck hepatitis B virus (DHBV) and human hepatitis B virus (HBV) core protein, either with wild type (WT) sequences or with alanine or aspartic acid substitutions at the phosphorylation sites. Two host proteins, B23 and I2PP2A, were found to interact preferentially with the alanine-substituted CTD. Furthermore, the WT CTD became competent to interact with the host proteins upon dephosphorylation. Intriguingly, the binding site on the DHBV CTD for both B23 and I2PP2A was mapped to a region upstream of the phosphorylation sites even though B23 or I2PP2A binding to this site was clearly modulated by the phosphorylation state of the downstream and non-overlapping sequences. Together, these results demonstrate a novel mode of phosphorylation-regulated protein-protein interaction and provide new insights into virus-host interactions.

Autogenous grafts for condylar reconstruction in treatment of TMJ ankylosis: current concepts and considerations for the future

Temporomandibular joint (TMJ) ankylosis is characterized by difficulty or inability to open the mouth due to fusion of the temporal and the mandible, resulting in facial symmetry/deformity, malocclusion and dental problems. The only treatment option for TMJ ankylosis is surgical with or without condylar reconstruction. Various autogenous grafts are available for condylar reconstruction after freeing the ankylotic mass such as costochondral, sternoclavicular, fibular, coronoid, and metatarsophalangeal. Costochondral graft is preferred by surgeons, but distraction osteogenesis is slowly gaining popularity and may ultimately become the standard procedure, providing a cost-effective approach with low morbidity and excellent functional outcomes. Tissue engineering is another budding field which has shown promising results in animal studies but has not been applied to humans. To date, there is no ideal autogenous graft for condylar reconstruction that satisfies the complex anatomy and the myriad of functions of a missing condyle.

Different iron-deposition patterns of multiple system atrophy with predominant parkinsonism and idiopathetic Parkinson diseases demonstrated by phase-corrected susceptibility-weighted imaging

BACKGROUND AND PURPOSE

MSA-P and IPD have similar clinical presentations that may complicate accurate clinical diagnosis. Different iron-deposition patterns of those 2 diseases have been demonstrated in histopathology. The aim was to demonstrate the different iron-deposition patterns of MSA-P and IPD by using SWI phase images.

MATERIALS AND METHODS

Sixteen patients with IPD, 8 with MSA-P, and 44 age-matched healthy controls underwent SWI of brain. The different phase shifts as well as the high iron percentage of the area in several gray nuclei were statistically evaluated. The putamen was divided into 4 subregions for further analysis.

RESULTS

Patients with MSA-P had significantly higher iron deposition in the putamen and PT compared with those with IPD (P < .05). Moreover, ROC curves indicated slightly more sensitivity in differentiating MSA-P from IPD, by means of the high-iron-deposition-percentage area than the average phase shift (putamen: AUC = 0.88 versus 0.78; PT: AUC = 0.79 versus 0.62). Moreover, the lower inner region of the putamen was the most valuable subregion in differentiating MSA-P from IPD among the 4 subregions (AUC = 0.92 and 0.91 for high-iron-percentage area and average phase shift, respectively).

CONCLUSIONS

Higher iron deposition in the putamen and PT may differentiate MSA-P from IPD, but the lower inner region of the putamen may be better compared with the PT and other subregions of the putamen. Moreover, the high iron percentage makes it possible to detect smaller increases in iron content more confidently in comparison with average phase shift.

Growth factor signalling in the regulation of α-cell fate

Glucagon plays critical roles in regulating glucose homeostasis, mainly by counteracting the effects of insulin. Consequently, the dysregulated glucagon secretion that is evident in type 2 diabetes has significant implications in the pathophysiology of the disease. Glucagon secretion from pancreatic α-cells has been suggested to be modulated by blood glucose, signals from the nervous system and endocrine components. In addition to these regulators, intraislet factors acting in a paracrine manner from neighbouring β-cells are emerging as central modulator(s) of α-cell biology. One of the most important of these paracrine factors, insulin, modulates glucagon secretion. Indeed, the α-cell-specific insulin receptor knockout (αIRKO) mouse manifests hypersecretion of glucagon in the postprandial stage and exhibits defective secretion in fasting-induced hypoglycaemia, together mimicking the α-cell defects observed in type 2 diabetes. Interestingly, αIRKO mice display a progressive increase in β-cell mass and a concomitant decrease in α-cells. Lineage trace analyses reveal that the new β-cells originate, in part, from the insulin receptor-deficient α-cells indicating a critical role for α-cell insulin signalling in determining β-cell origin. Our studies also reveal that glucagon-like peptide-1 (GLP-1) treatment of αIRKO mice suppresses glucagon secretion despite absence of functional insulin receptors precluding a role for insulin in GLP-1 action on α-cells in this model. These findings highlight the significance of insulin signalling in the regulation of α-cell biology.

Decreased gray matter concentration and local synchronization of spontaneous activity in the motor cortex in Duchenne muscular dystrophy

BACKGROUND AND PURPOSE

Patients with DMD have demonstrated functional abnormalities in the motor-related brain areas in previous PET, MRS, and TMS studies. We applied structural MR imaging and RS-fMRI in patients with DMD for the first time, and aimed to investigate the GMC and ReHo or local synchronization of spontaneous activity in the motor cortex.

MATERIALS AND METHODS

Ten boys with DMD (6.4-14.0 years of age) and 15 healthy controls (7.9-15.1 years of age) underwent brain structural MR imaging and RS-fMRI scanning. GMC and local synchronization of spontaneous activity in the motor cortex were analyzed by using VBM and ReHo approaches, respectively.

RESULTS

Compared with healthy controls, boys with DMD showed decreased GMC in the left PSMC and decreased ReHo in the bilateral PMSC as well as in the supplementary motor area (P < .05, corrected).

CONCLUSIONS

The current results indicate that boys with DMD have both GMC loss and decreased local synchronization of spontaneous activity in the motor cortex, which might be due to the deficiency of dystrophin in the brain.

Dual-band spectral-domain optical coherence tomography for in vivo imaging the spectral contrasts of the retinal nerve fiber layer

The ultimate goal of the study is to provide an imaging tool to detect the earliest signs of glaucoma before clinically visible damage occurs to the retinal nerve fiber layer (RNFL). Studies have shown that the optical reflectance of the damaged RNFL at short wavelength (<560 nm) is reduced much more than that at long wavelength, which provides spectral contrast for imaging the earliest damage to the RNFL. To image the spectral contrast we built a dual-band spectral-domain optical coherence tomography (SD-OCT) centered at 808 nm (NIR) and 415 nm (VIS). The light at the two bands was provided by the fundamental and frequency-doubled outputs of a broadband Ti:Sapphire laser. The depth resolution of the NIR and VIS OCT systems are 4.7 µm and 12.2 µm in the air, respectively. The system was applied to imaging the rat retina in vivo. Significantly different appearances between the OCT cross sectional images at the two bands were observed. The ratio of the light reflected from the RNFL over that reflected from the entire retina at the two bands were quantitatively compared. The experimental results showed that the dual-band OCT system is feasible for imaging the spectral contrasts of the RNFL.