Spectrum of Skin Lesions of Post-Kala-Azar Dermal Leishmaniasis in Kala-azar Endemic Areas of Bangladesh

Post-kala-azar dermal leishmaniasis (PKDL) is a complication of visceral leishmaniasis (VL) and serves as a potential reservoir for Leishmania parasite. The study was aimed to evaluate the spectrum of skin lesions of PKDL in kala-azar endemic areas in Bangladesh. This cross sectional study was carried out to observe the characteristics of skin lesions among 250 PKDL cases. The suspected PKDL patients in highly endemic villages of Fulbaria Upazilla of Mymensingh district.were subjected to a dipstick test (rK39) for kala azar. The median time interval between diagnosing kala-azar and PKDL was 23 month (m-21, r- 0-60 months). The most common skin lesions were multiple symmetrical hypopigmented macules with irregular margins in 179(71.6%) cases followed by erythematous facial induration in 74(29.6%), papular in 33(13.2%), nodular in 28(11.2%) cases, combination of macules, papules, nodules and plaques in 88(35.2%) cases, annular in 7(2.8%) cases and Papillomatous mucosal growth in 2(0.8%) cases. Sites of involvement were mostly in face (92.4%), Trunk (84.8%), extremities (33.2%), oral mucosa and tongue (0.8%) and Genitalia (1.2%). Suspicion of PKDL on the basis of skin lesions will lead to early diagnosis and prompt treatment will impart an important role in prevention and eradication of Leishmaniasis in Bangladesh.     

Design and Validation of Additively Manufactured Metallic Cellular Scaffold Structures for Bone Tissue Engineering

Bone-related defects that cannot heal without significant surgical intervention represent a significant challenge in the orthopedic field. The use of implants for these critical-sized bone defects is being explored to address the limitations of autograft and allograft options. Three-dimensional cellular structures, or bone scaffolds, provide mechanical support and promote bone tissue formation by acting as a template for bone growth. Stress shielding in bones is the reduction in bone density caused by the difference in stiffness between the scaffold and the surrounding bone tissue. This study aimed to reduce the stress shielding and introduce a cellular metal structure to replace defected bone by designing and producing a numerically optimized bone scaffold with an elastic modulus of 15 GPa, which matches the human’s cortical bone modulus. Cubic cell and diagonal cell designs were explored. Strut and cell dimensions were numerically optimized to achieve the desired structural modulus. The resulting scaffold designs were produced from stainless steel using laser powder bed fusion (LPBF). Finite element analysis (FEA) models were validated through compression testing of the printed scaffold designs. The structural configuration of the scaffolds was characterized with scanning electron microscopy (SEM). Cellular struts were found to have minimal internal porosity and rough surfaces. Strut dimensions of the printed scaffolds were found to have variations with the optimized computer-aided design (CAD) models. The experimental results, as expected, were slightly less than FEA results due to structural relative density variations in the scaffolds. Failure of the structures was stretch-dominated for the cubic scaffold and bending-dominated for the diagonal scaffold. The torsional and bending stiffnesses were numerically evaluated and showed higher bending and torsional moduli for the diagonal scaffold. The study successfully contributed to minimizing stress shielding in bone tissue engineering. The study also produced an innovative metal cellular structure that can replace large bone segments anywhere in the human body.     

Usage of nanoparticles with their potential toxicity assessment and regulatory guidelines

In recent times engineered nanoparticles have been receiving much attention from researchers due to their extensive use in a variety of chemical, biological, and industrial areas. Their physiochemical properties have led to a number of uses in commercial products. Considering their broad applications, with increasing human contact the risks of exposure are also increasing. In vivo toxicity experiments involving administering nanoparticles to living organisms have shown their adverse effects on organ development and reproduction. Nanoparticles can be considerably more toxic than the large-sized particles since they can move relatively freely compared to bulkier molecules. Henceforth, it is our duty to assess the harmful health consequences associated with human exposure to nanoparticles in order to improve safe production and use. We will review the current applications of nanoparticles, and issues related to their toxicity. We will focus on safety regulations, risk assessment and regulatory guidelines of nanoparticles. The validation and standardization of nanotoxicity tests will further promote safe applications of nanotechnology in our daily lives.     

Late-presenting complete heart block after pediatric cardiac surgery

Late presenting complete heart block after pediatric cardiac surgery is a rare complication and its management is well defined once the initial diagnosis in made timely and appropriately. In this report we described a child who underwent atrioventricular septal defect repair with a normal sinus rhythm during the postoperative period, as well as during the first 2 years of follow up.She subsequently developed complete heart block with bradycardia that required insertion of a pacemaker. Here we discuss this unusual late-presenting complication, possible risk factors, and management.     

Chemometric Evaluation of Near Infrared,Fourier Transform Infrared,and Raman Spectroscopic Models for the Prediction of Nimodipine Polymorphs

The objective of this study was to assess the performance of the chemometric model to predict the proportion of the recrystallized polymorphs of nimodipine from the cosolvent formulations. Ranging from 100% to 0% (w/w) of polymorph I, the two polymorphs mixtures were prepared and characterized spectroscopically using Fourier transformed infrared spectroscopy (FTIR), near-infrared spectroscopy (NIR), and Raman spectroscopy. Instrumental responses were treated to construct multivariate calibration model using principal component regression (PCR) and partial least square regression approaches. Treated data showed better model fitting than without treatment, which demonstrated higher correlation coefficient (R²) and lower root mean square of standard error (RMSE) and standard error (SE). Multiple scattering correction and standard normal variate exhibited higher R² and lower RMSE and SE values than second derivative. Goodness of fit for FTIR and NIR (R² ~ 0.99) data was better than Raman (R² ~ 0.95). Furthermore, the models were applied on the recrystallized polymorphs obtained by storing nimodipine-cosolvent formulations at selected stability conditions. The relative composition of the polymorphs differed with storage conditions. NIR-chemical imaging on recrystallized sample of nimodipine at 15°C qualitatively corroborated the model-based prediction of the two polymorphs. Therefore, these studies strongly suggest the importance of the potential utility of the chemometric model in predicting nimodipine polymorphs.     

变黑白头翁提取物降低亚砷酸盐对小鼠精细胞的毒性

目的：研究变黑白头翁提取物降低亚砷酸盐对小鼠精细胞毒性的作用。方法：给予实验小鼠亚砷酸钠（20mg／kg每日），并分别在第30、60、90天对小鼠进行检测。亚砷酸盐中毒小鼠被分为2组，其中一组给予变黑白头翁提取物（35mg／kg），另一组给予85％乙醇。通过检测小鼠精细胞凋亡标志蛋白CYP1A1、p53及caspase3的活性，确定细胞及DNA的损伤情况，并测定睾丸毒性标志物的水平。通过圆二色光谱仪及熔化温度数据检测变黑白头翁提取物与DNA的相互作用情况。结果：亚砷酸盐中毒小鼠的所有细胞凋亡标志蛋白及睾丸毒性标志物的水平均有所上升，而经变黑白头翁提取物治疗的小鼠上述各项指标均降低或恢复至正常水平。变黑白头翁提取物与DNA相互作用，引起了DNA结构和构象的变化。结论：变黑白头翁提取物可作为砷中毒引起的生殖功能损害的治疗药物给予研究和开发。