Crystallization and Morphological Features of Syndiotactic/Atactic Polystyrene Blends at High Temperatures

Crystalline/amorphous binary mixtures of polystyrene with different tacticities, syndiotactic/atactic isomers (sPS/aPS), have been systematically studied to reveal the composition dependence of the blend morphologies, i.e., sPS lamellar structure and aPS diluent segregation, developed after isothermal crystallization. To reveal the molecular weight effect of the aPS diluents, four different of aPS were used to prepare blends with various compositions. After being melt crystallized isothermally at 250 °C, all blends were investigated by means of POM, WAXS, and SAXS as well as SEM and TEM to reveal the spherulitic and lamellar morphologies developed.

     

Epithelial cells trigger frontline immunoglobulin class switching through a pathway regulated by the inhibitor SLPI

Epithelial cells (ECs) transport class-switched immunoglobulin G (IgG) and IgA antibodies across mucous membranes. Whether ECs initiate class switching remains unknown. Here we found that ECs lining tonsillar crypts formed pockets populated by B cells expressing activation-induced cytidine deaminase (AID), an enzyme associated with ongoing class switching. ECs released B cell-activating AID-inducing factors after sensing microbial products through Toll-like receptors. The resulting class switching was amplified by thymic stromal lymphopoietin, an epithelial interleukin 7-like cytokine that enhanced the B cell 'licensing' function of dendritic cells, and was restrained by secretory leukocyte protease inhibitor, an epithelial homeostatic protein that inhibited AID induction in B cells. Thus, ECs may function as mucosal 'guardians' orchestrating frontline IgG and IgA class switching through a Toll-like receptor-inducible signaling program regulated by secretory leukocyte protease inhibitor.NOTE: In the version of this article initially published online, the middle label above Figure 6c is incorrect. The correct label should be 'BAFF'. The error has been corrected for all versions of the article.     

Effects of a p38 MAP kinase inhibitor on bone ingrowth and tissue differentiation in rabbit chambers

The effects of an oral p38 mitogen-activated protein kinase (MAPK) inhibitor and polyethylene particles separately and together on tissue differentiation in the bone harvest chamber (BHC) in rabbits over a 3-week treatment period were investigated. The harvested tissue was analyzed histomorphometrically for markers of bone formation (percentage of bone area), osteoblasts (alkaline phosphatase staining), and osteoclasts (CD51, the alpha chain of the vitronectin receptor). Polyethylene particles decreased the percentage of bone ingrowth and staining for alkaline phosphatase. The p38 MAPK inhibitor alone decreased alkaline phosphatase staining. When the oral p38 MAPK inhibitor was given and the chamber contained polyethylene particles, there was a suppression of bone ingrowth and alkaline phosphatase staining. In contrast to oral non-steroidal anti-inflammatory drugs (NSAIDs) and local Interleukin-1 receptor antagonist (IL-1ra) administration, the oral p38 MAPK inhibitor alone did not suppress bone formation when given during the initial phase of tissue differentiation. Particle-induced inflammation and the foreign body reaction were not curtailed when the p38 MAPK inhibitor was given simultaneously with particles. Additional experiments are needed to establish the efficacy of p38 MAPK inhibitor administration on mitigating an established inflammatory and foreign body reaction that parallels the clinical situation more closely.     

Modulation of chondrocyte phenotype via baculovirus-mediated growth factor expression

Baculovirus has emerged as a new gene delivery vector thanks to a number of advantages. This study demonstrated that baculovirus conferred efficient gene delivery and mediated expression of growth factors (TGF-beta1, IGF-1 and BMP-2) to therapeutic levels in rabbit chondrocytes. Interestingly, the cellular response to growth factor stimulation was dependent on the cell passage. The highly de-differentiated passage 5 (P5) chondrocytes failed to respond to the stimulation by either growth factor. The de-differentiated P3 cells also failed to maintain the chondrocyte phenotype, but baculovirus-mediated BMP-2 expression remarkably reversed the de-differentiation and enhanced the aggrecan and collagen II production in 2D and 3D cultures, as evidenced by cell morphology, histological staining and gene expression analyses. Baculovirus-mediated TGF-beta1 expression modestly enhanced the cartilage-specific matrix production, although to a lesser extent. Intriguingly, IGF-1, a well-known chondroinductive protein, failed to stimulate the P3 cells likely due to the loss of IGF-1 receptor expression. In summary, this study proved for the first time the potentials of baculovirus in modulating the differentiation status of chondrocytes in the context of cartilage tissue engineering, but also highlighted the importance of selecting appropriate cell passage and growth factor for genetic manipulation.     

The tablet formulation of lopinavir/ritonavir provides similar bioavailability to the soft-gelatin capsule formulation with less pharmacokinetic variability and diminished food effect

Lopinavir, an HIV protease inhibitor, is coformulated with ritonavir to enhance the bioavailability and pharmacokinetics of lopinavir. The original solid oral formulation of lopinavir/ritonavir, a soft-gelatin capsule (SGC), requires refrigerated storage, is taken as 6 capsules daily at the recommended adult dose, and is administered with food to maximize the bioavailability of lopinavir. Melt extrusion technology was used to produce a tablet formulation reducing the number of dosage units administered per day and simplifying storage requirements. Three studies assessed the bioavailability of tablet doses of lopinavir/ritonavir at 800/200 mg or 400/100 mg under different meal conditions compared with equal doses of the SGC after a moderate-fat meal. The tablet was bioequivalent to the SGC after a moderate-fat meal with respect to lopinavir and ritonavir areas under the concentration-time curve. Compared with the SGC formulation, the tablet formulation resulted in more consistent lopinavir and ritonavir exposures within and across studies and across meal conditions. The diminished food effect and decreased variability of the tablet are likely to result in more consistent lopinavir and ritonavir exposures, minimizing the likelihood of extreme high or low values compared with the SGC.     

The Prevalence of and Risk Factors for Neck Pain and Upper Limb Pain among Secondary School Teachers in Hong Kong

Objective: To investigate the prevalence and occupational risk factors of neck and upper limb disorders among secondary school teachers. Methods: One hundred secondary schools in Hong Kong were randomly chosen. Every full-time teacher received a questionnaire and a letter describing the purpose of the study. Questionnaires were collected 1 to 3 weeks later. Results: Among 3,100 secondary school teachers, the lifelong prevalence of neck pain and upper limb pain was 69.3% (2091/3018) and 35.8% (1088/3042) respectively. The lifelong cumulative incidence of both neck and upper limb pain was 31.6% (938/2966). Multiple logistic regression analysis showed that gender, age and working in head down posture were identified as risk factors for neck and upper limb pain. High workload, low colleague support and high anxiety were found to be significant on affecting the neck pain and upper limb pain developed after becoming teachers. Conclusions: Neck pain and upper limb pain were highly prevalent in secondary school teachers in Hong Kong. Gender, age, head down posture and some psychological factors were found to be significant risk factors.     

Effect of purple sweet potato leaves consumption on the modulation of the immune response in basketball players during the training period

The aim of this study was to evaluate the effect of the consumption of purple sweet potato leaves (PSPLs) on the immune response and the modulation of that response in 15 basketball players during a training period. They completed the 7-week study consisted of a run-in period (week 1), a PSPLs diet (200 g PSPLs/d; weeks 2, 3), a washout period (weeks 4, 5), and a control diet (low polyphenols content and carotenoid content adjusted to the same level as that of PSPLs diet; weeks 6 and 7). Blood, urine, and saliva samples were collected for biochemical analysis. The results showed that the plasma polyphenols concentration increased significantly in the PSPLs period. Compared with the control period, the PSPLs consumption produced a significant increase in the proliferation responsiveness of peripheral blood mononuclear cells (PBMC), cytotoxic activity of nature killer (NK) cells, and secretion of interferon (IFN)-gamma. However, no significant increase in the secretion of salivary immunoglobulin A (sIgA), interleukin (IL)-2, or interleukin-4 was observed after PSPLs consumption. In conclusion, consumption of a PSPLs diet for 2 weeks can modulate the immune response of basketball players during a training period.     

Association between dietary glycemic index and age-related macular degeneration in nondiabetic participants in the Age-Related Eye Disease Study

BACKGROUND: Age-related macular degeneration (AMD) is the major cause of irreversible blindness. AMD appears to share several carbohydrate-related mechanisms and risk factors with diabetes-related diseases, including retinopathy and cardiovascular disease (CVD); however, to date, only one small study has addressed this issue. OBJECTIVE: The objective was to test the hypothesis that dietary glycemic index (dGI), which has been related to the risk of diabetes and CVD, is associated with the risk and severity of AMD in nondiabetic elderly populations. DESIGN: Dietary information was obtained from 4099 participants aged 55-80 y (56% women) in the Age-Related Eye Disease Study (AREDS). A total of 8125 eligible eyes at baseline were classified into 1 of 5 AMD groups according to the size and extent of drusen, the presence of geographic atrophy, and neovascular changes. We used a generalized estimating approach to evaluate the relations between dGI and risk and severity of AMD with eyes as the unit of analysis. RESULTS: Compared with eyes in the first quintile of dGI, eyes in the fourth and fifth quintiles had a significantly or suggestively higher risk of large drusen, geographic atrophy, and neovascularization. The multivariate-adjusted odds ratios (95% CIs) for the highest quintile were 1.42 (1.09, 1.84), 1.78 (0.81, 3.90), and 1.41 (0.95, 2.08), respectively, of which only the odds ratio for large drusen was significant. A significant positive relation between dGI and severity of AMD was also noted (P for trend < 0.001). There was a 49% increase in the risk of advanced AMD (geographic atrophy plus neovascularization) for persons with a dGI higher than the sex median (women: >or=77.9; men: >or=79.3). This result indicated that 20% of prevalent cases of AMD would have been eliminated if the AREDS participants consumed diets with a dGI below the median. CONCLUSION: The association between dGI and AMD from the AREDS cross-sectional analysis at baseline suggests that a reduction in the dGI, a modifiable risk factor, may provide a means of diminishing the risk of AMD.