Fluid-structure interaction (FSI) modeling of bone marrow through trabecular bone structure under compression.

The present study has sought to investigate the fluid characteristic and mechanical properties of trabecular bone using fluid-structure interaction (FSI) approach under different trabecular bone orientations. This method imposed on trabecular bone structure at both longitudinal and transverse orientations to identify effects on shear stress, permeability, stiffness and stress regarded to the trabeculae. Sixteen FSI models were performed on different range trabecular cubes of 27 mm3 with eight models developed for each longitudinal and transverse direction. Results show that there was a moderate correlation between permeability and porosity, and surface area in the longitudinal and transverse orientations. For the longitudinal orientation, the permeability values varied between 3.66 × 10-8 and 1.9 × 10-7 and the sheer stress values varied between 0.05 and 1.8 Pa, whilst for the transverse orientation, the permeability values varied between 5.95 × 10-10 and 1.78 × 10-8 and the shear stress values varied between 0.04 and 3.1 Pa. Here, transverse orientation limits the fluid flow from passing through the trabeculae due to high shear stress disturbance generated within the trabecular bone region. Compared to physiological loading direction (longitudinal orientation), permeability is higher within the range known to trigger a response in bone cells. Additionally, shear stresses also increase with bone surface area. This study suggests the shear stress within bone marrow in real trabecular architecture could provide the mechanical signal to marrow cells that leads to bone anabolism and can depend on trabecular orientation.

Thraatchathi Chooranam, protects cardiomyocytes against oxidative stress.

Thraatchathi Chooranam (TC), is a polyphenol-rich Indian traditional medicine. Present study was undertaken to investigate the effects of TC against H2O2 induced oxidative stress and apoptotic damage in H9C2 cardiomyocytes. Cell viability assay indicated relative safety (IC50= 488.10±12.04 mg/ml) of TC. Pretreatment of cells with TC upregulated anti-apoptotic Bcl2, and anti-oxidants TRX1 and TRXR and downregulated Bax and HIF-α and inflammatory genes iNOS and TNF-α. Together, these findings show that TC has both anti-oxidant and anti-apoptotic properties. Further studies may be considered to identify the bioactive principle(s) and precise mechanisms of action of TC.

Assessment of knowledge regarding tuberculosis among non-medical university students in Bangladesh: a cross-sectional study.

BACKGROUND: Tuberculosis (TB) is the second leading cause of human death and TB is one of the major public health problems in Bangladesh. The aim of the present study was to assess the Knowledge about TB among non-medical university students in Bangladesh. METHODS: A cross-sectional survey was performed on 839 non-medical university students. Data were collected from University of Rajshahi from March to August 2013 using a standard semi-structured questionnaire. Chi-square test was utilized to find the factors which are associated with students' knowledge about TB. RESULTS: Among 839 students, male and female were 68.2 % and 31.8 % respectively. Most of the students (94.4 %) were informed about the term TB, among them 50 % got information from electronic media. More than 50 % students believed that TB is a communicable disease, 42.8 % students agreed that bacteria is an agent for TB, most of the subjects (93 %) had the knowledge about the vaccination against TB and 97.6 % students believed that TB is curable. However, students had poor knowledge about latent TB (13.7 %) and DOTs program (28.5 %). χ (2)-test demonstrated that gender, residence, type of family and parents education were associated with students' knowledge of TB. CONCLUSION: In the present study demonstrated that the level of general knowledge about TB was insufficient among non-medical university students. Consequently, health education program is needed to improve the knowledge among university students regarding TB.

Chondrocyte density, proteoglycan content and gene expressions from native cartilage are species specific and not dependent on cartilage thickness: a comparative analysis between rat, rabbit and goat.

BACKGROUND: In many pre-clinical studies of cartilage tissue, it has been generally assumed that the major difference of the tissue between the species is the tissue thickness, which is related to the size of the animal itself. At present, there appear to be lack of studies demonstrating the relationship between chondrocyte densities, protein content, gene expressions and cartilage thickness in the various animal models that are commonly used. The present study was conducted to determine whether or not chondrocyte density, proteoglycan/protein content and selective chondrocyte gene expression are merely related to the cartilage thickness (thus animal size), and not the intrinsic nature of the species being investigated. Mature animals (rabbit, rats and goats) were sacrificed for their hind knee cartilages. Image analyses were performed on five consecutive histological sections, sampled from three pre-defined locations at the lateral and medial femoral condyles. Cartilage thickness, chondrocyte density, Glycosaminoglycan (GAGs)/protein content and gene expression levels for collagen II and SOX-9 were compared across the groups. Correlation analysis was done between cartilage thickness and the other variables. RESULTS: The mean cartilage thickness of rats, rabbits and goats were 166.5 ± 10.9, 356.2 ± 25.0 907.5 ± 114.6 µm, respectively. The mean cartilage cell densities were 3.3 ± 0.4×10(-3) for rats, 2.6 ± 0.3×10(-3) for rabbits and 1.3 ± 0.2×10(-3) cells/µm2 for goats. The mean µg GAG/mg protein content were 23.8 ± 8.6 in rats, 20.5 ± 5.3 in rabbits and 328.7 ± 64.5 in goats; collagen II gene expressions were increased by 0.5 ± 0.1 folds in rats; 0.6 ± 0.1 folds in rabbits, and 0.1 ± 0.1 folds in goats, whilst the fold increase of SOX-9 gene expression was 0.5 ± 0.1 in rats, 0.7 ± 0.1 in rabbits and 0.1 ± 0.0 in goats. Cartilage thickness correlated positively with animals' weight (R2 =0.9856, p = 0.001) and GAG/protein content (R2 =0.6163, p = <0.001). Whereas, it correlates negatively with cell density (R2 = 0.7981, p < 0.001) and cartilage gene expression levels (R2 = 0.6395, p < 0.001). CONCLUSION: There are differences in the composition of the articular cartilage in diverse species, which are not directly dependent on the cartilage thickness of these animals but rather the unique characteristics of that species. Therefore, the species-specific nature of the cartilage tissue should be considered during any data interpretation.

Age at menarche of university students in Bangladesh: secular trends and association with adult anthropometric measures and socio-demographic factors.

Age at menarche has been shown to be an important indicator for diseases such as breast cancer and ischaemic heart disease. The aim of the present study was to document secular trends in age at menarche and their association with anthropometric measures and socio-demographic factors in university students in Bangladesh. Data were collected from 995 students from Rajshahi University using a stratified sampling technique between July 2004 and May 2005. Trends in age at menarche were examined by linear regression analysis. Multiple regression analysis was used to assess the association of age at menarche with adult anthropometric measures and various socio-demographic factors. The mean and median age of menarche were 13.12+/-1.16 and 13.17 years, respectively, with an increasing tendency among birth-year cohorts from 1979 to 1986. Menarcheal age was negatively associated with BMI (p<0.01), but positively associated with height (p<0.05). Early menarche was especially pronounced among students from urban environments, Muslims and those with better educated mothers. Increasing age at menarche may be explained by improved nutritional status among Bangladeshi populations. Early menarche was associated with residence location at adolescence, religion and mother's education.