Hydroxyapatite (HA) has been used clinically for many years. It has good biocompatibility in bone contact as its chemical composition is similar to that of bone material. Porous HA ceramics have found enormous use in biomedical applications including bone tissue regeneration, cell proliferation, and drug delivery. In bone tissue engineering it has been applied as filling material for bone defects and augmentation, artificial bone graft material, and prosthesis revision surgery. Its high surface area leads to excellent osteoconductivity and resorbability providing fast bone ingrowth. Porous HA can be produced by a number of methods including conversion of natural bones, ceramic foaming technique, polymeric sponge method, gel casting of foams, starch consolidation, microwave processing, slip casting, and electrophoretic deposition technique. Some of these methods have been combined to fabricate porous HA with improved properties. These combination methods have yielded some promising results. This paper discusses briefly fundamental aspects of porous HA for artificial bone applications as well as various techniques used to prepare porous HA. Some of our recent results on development of porous HA will be presented as well. r
The global epidemiology of atopic dermatitis (AD) in the current decade (2009–2019) has not been extensively reported. Epidemiological studies play an important role in presenting the risk factors of AD, as detailed prevalence and incidence data could demonstrate the burden of disease in the population of adults, adolescents, and children in different geographical regions. Thus, the primary objective of this review was to assess and summarize the epidemiological studies of the prevalence and incidence of AD in different age groups, focusing on data from studies published for 2009 to 2019. After a thorough literature search, six countries were identified from African, Asian, and European regions respectively, who published studies on AD. In contrast, only two studies were identified from Australia and New Zealand, three countries from North America and two from South America published AD studies, respectively. The highest prevalence of AD from included studies was noted among Swedish children with 34%, while the lowest prevalence was in Tunisian children with 0.65%; studies reporting incidence data were far less numerous. A common trend in the prevalence of AD was that children would have a higher prevalence as compared to adolescents and adults. The severity and morbidity of the disease showed variance with age, sex, socioeconomic characteristics, geographical location, and ethnicity. Environmental factors played an important role as causative agents in AD. The risk factors that were proven to cause and induce AD were skin barrier impairments due to FLG mutation, changes in the environment, and diet. FLG mutation may impair the skin barrier function by disruption of pH and hydration maintenance of the skin. Lastly, there were only a few studies on the incidence of AD in the 21st century. Therefore, epidemiological studies on childhood and adulthood AD in different continents are still needed, especially on the incidence of AD during adulthood.
Sclerostin has emerged as an important regulator of bone mass. We have shown that sclerostin can act by targeting late osteoblasts/osteocytes to inhibit bone mineralization and to upregulate osteocyte expression of catabolic factors, resulting in osteocytic osteolysis. Here we sought to examine the effect of exogenous sclerostin on osteocytes in trabecular bone mechanically loaded ex vivo. Bovine trabecular bone cores, with bone marrow removed, were inserted into individual chambers and subjected to daily episodes of dynamic loading. Cores were perfused with either osteogenic media alone or media containing human recombinant sclerostin (rhSCL) (50 ng/ml). Loaded control bone increased in apparent stiffness over time compared with unloaded bone, and this was abrogated in the presence of rhSCL. Loaded bone showed an increase in calcein uptake as a surrogate of mineral accretion, compared with unloaded bone, in which this was substantially inhibited by rhSCL treatment. Sclerostin treatment induced a significant increase in the ionized calcium concentration in the perfusate and the release of β-CTX at several time points, an increased mean osteocyte lacunar size, indicative of osteocytic osteolysis, and the expression of catabolism-related genes. Human primary osteocyte-like cultures treated with rhSCL also released β-CTX from their matrix. These results suggest that osteocytes contribute directly to bone mineral accretion, and to the mechanical properties of bone. Moreover, it appears that sclerostin, acting on osteocytes, can negate this effect by modulating the dimensions of the lacunocanalicular porosity and the composition of the periosteocyte matrix.
INTRODUCTION Diabetes mellitus (DM) is the most common cause of amputations in Malaysia. This study aimed to identify the predictive factors for major lower limb amputation among patients with type 2 DM (T2DM) who were admitted to a hospital, in order to reduce its likelihood. METHODSThis cross-sectional study involved 218 patients with T2DM who were admitted to Hospital Tengku Ampuan Afzan, Kuantan, Malaysia, for diabetic foot problems from June 2011 to July 2012. A form was developed to document the patients' profiles, comorbidities, complications, investigations, treatment and clinical outcomes. The predictors for major lower limb amputations were determined using univariate and stepwise logistic regression analysis. RESULTSA total of 31 patients underwent major lower limb amputations (25 transtibial, 6 transfemoral). The following factors were found to be associated with the incidence of major lower limb amputations: T2DM duration ≥ 10 years, diabetic neuropathy, diabetic nephropathy, presentation with gangrene, diabetic foot conditions of Wagner grade 4 or 5, and necrotising fasciitis. Patients who underwent major amputations had significantly lower haemoglobin and albumin levels, and higher total white blood cell counts, erythrocyte sedimentation rates, and C-reactive protein, urea and creatinine levels. However, only T2DM duration ≥ 10 years, positive bacterial culture and albumin levels were significant on stepwise logistic regression analysis.CONCLUSION T2DM duration ≥ 10 years, positive bacterial culture and low albumin levels were found to be significant predictive factors for major lower limb amputation among patients with T2DM admitted for diabetic foot problems.
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