Phenotypic variation in biofilm formation is common in clinical isolates of S. epidermidis. In the current study, nearly 5% of all clinical isolates analysed showed phenotypic variation in biofilm forming ability and electrophoretic mobility (EM). This is the first report of S. epidermidis strains irreversibly switching from biofilm-positive to biofilm-negative phenotype by spontaneous deletion of icaADBC genes which represents a new, possibly common mechanism of phenotypic variation.
Improvement of the mechanical properties of hydroxyapatite (HA) can be achieved by the incorporation of metal. In addition, incorporation of strontium ion into HA crystal structures has been proved effective to enhance biochemical properties of bone implant. In this research, strontium-doped HA powder was developed via a sol-gel method to produce extraordinarily fine strontium-doped HA (Sr-doped HA) powder. XRD measurement had shown that the powder contained hydroxyapatite phase only for all doping concentration except for 2%, showing that Sr atoms have suppressed the appearance of beta-TCP as the secondary phase. Morphological evaluation by FESEM measurement shows that the particles of the Sr-doped HA agglomerates are globular in shape with an average size of 1-2 microm in diameter while the primary particles have a diameter of 30-150 nm in average.
The immune modulatory properties of mesenchymal stem cell (MSC) had brought a new insight in cell-based neotherapy. However, recent works of MSC are focused exclusively on bone marrow-derived MSC. We evaluated the immunogenicity of cord blood-derived MSC (CB-MSC) on T lymphocytes. Human peripheral blood mononuclear cells (PBMC) were prepared by density gradient separation and culture with the presence or absence of CB-MSC. PBMC were collected for activation analysis by flow cytometry at 24-, 48-, and 72- hours. The results showed that, CB-MSC does not stimulate nor inhibit T lymphocyte activation.
Amniotic fluid (AF) serves as an excellent alternative source of pluripotent stem cells, as they are not bound with ethical issues and the stem cells are more primitive than adult stem (AS) cells. Hence, they have higher potential. Here we aim to isolate and characterize pluripotent stem cells from mid-term and full-term pregnant rat amniotic fluid. The results demonstrate the evidence of heterogeneous population of cells in the amniotic fluid and some of the cells morphology shows similarity with ES cells.
Aqueous extract of Ficus deltoidea var. agustifolia was examined for the subchronic toxicity effects in rats. Groups of 10 rats were given the extract daily by oral gavage for 90 days at 0 (control), 100 and 300mg/kg/body weight, respectively. Blood samples were collected upon sacrificed and analysed for haemogram and biochemistry. The results showed there were no significant changes of the blood parameters in all treated groups compared to the control.
Lead (Pb) is a neurotoxic heavy metal and children in the developmental stage are particularly susceptible to toxic effects of lead exposure. The brain is the key organ involved in interpreting and responding to potential stressors. Epidemiological investigations have established the relationship between chronic lead exposure and cognitive impairments in young children. Excessive production of radical species plays an important role in neuronal pathology resulting from excitotoxic insults, therefore one plausible neuroprotective mechanism of bioflavonoids is partly relevant to their metal chelating and antioxidant properties. Centella asiatica (CA) is a tropical medicinal plant enriched with bioflavonoids and triterpenes and selenium, reported to rejuvenate the cells and promote physical and mental health. Bioflavonoids are claimed to be exert antimutagenic, neurotrophic and xenobiotics ameliorating and membrane molecular stabilizing effects. The objective of the present work is to study the protective antioxidant effect of pretreatment of CA extract (CAE) on lead acetate induced changes in oxidative biomarkers in the central nervous system (CNS) of mice.
Validation of housekeeping gene is important for accurate quantitation of RNA in real time RT-PCR technique. The purpose of this study was to determine the validity of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as a housekeeping gene for quantitative real time RT-PCR assessment in human skin fibroblast senescent model. The cells were divided into different treatment groups; young (passage 4), senescent (passage 30), treatment with H2O2 and treatment with A-tocotrienol prior to H2O2 treatment. Our results showed that the expression level of GAPDH was constant with different treatment groups. Therefore, we concluded that GAPDH was suitable to be used as housekeeping gene in human skin fibroblast senescent model.
Stress-induced premature senescence (SIPS) model is in vitro model of cellular aging. In this study, apoptosis was evaluated in SIPS model and in replicative senescent fibroblasts. We also compared the activity of senescence-associated beta-galactosidase (SA-beta gal) as a biomarker of cellular aging. Our results suggested that SIPS model and senescent fibroblasts might share similar mechanism of aging and apoptosis pathway.
Basic fibroblast growth factor (bFGF) is angiogenic and effective in down-regulating excess collagen production. The aim of this study is to evaluate the effectiveness of vitamin E (Tocotrienol Rich Fraction) in altering the level of bFGF, a cytokine involved in the scar formation process. In this model, normal human fibroblasts were treated with various concentrations of vitamin E at different time frames. The levels of bFGF were determined by Enzyme-Linked Immunosorbant Assay (ELISA). This study demonstrated that Tocotrienol Rich Fraction (TRF) stimulated bFGF production by fibroblast and postulate that vitamin E may decrease aberrant scar formation.
Bone formation is an active process whereby osteoblasts are found on the surface of the newly formed bone. Adhesion to extracellular matrix is essential for the development of bone however not all surfaces are suitable for osteoblast adhesion and don't support osteoblastic functions. The objective of this study was to test the suitability of a collagen based microcarrier which would support osteoblastic functions.
This study aims at investigating the mechanical properties of the contemporary metallic bone plates determining the effect of their length, width and thickness on the properties and compares with the composite bone plates. Three-points bending test was performed over the stainless steel plates of different length, width and thickness. The test results showed that different plates had different mechanical properties. However, the properties are still much higher than that of particular bones intended to be treated. Therefore, the reported findings strongly encourage developing composite bone plates with biocompatible polymers/fibers that would have modulated properties according to the requirements.
The sintering behaviour of a commercial HA and synthesized HA was investigated over the temperature range of 700 degrees C to 1400 degrees C in terms of phase stability, bulk density, Young's modulus and Vickers hardness. In the present research, a wet chemical precipitation reaction was successfully employed to synthesize a submicron, highly crystalline, high purity and single phase stoichiometric HA powder that is highly sinteractive particularly at low temperature regimes below 1100 degrees C. It has been revealed that the sinterability of the synthesized HA was significantly greater than that of the commercial HA. The temperature for the onset of sintering and the temperature required to achieve densities above 98% of theoretical value were approximately 150 degrees C lower for the synthesized HA than the equivalent commercial HA. Nevertheless, decomposition of HA phase upon sintering was not observed in the present work for both powders.
In this study, porous hydroxyapatite (HA) samples were fabricated via sponge techniques with the aid of sago as part of the binder mixture. Development processes for the production of porous bone graft substitutes are studied using polyurethane sponge. To obtain the optimum amount of binder for successful fabrication of porous HA were done. Initially, porous HA powder was synthesized using calcium hydroxide and orthorphosphoric acid. Meanwhile, sago was mixed with PVA in a certain ratio to be used as binder for preparing the porous HA. After a series of investigative tests were conducted to characterize the sintered samples, the use of the sago and polymeric mixture was found to successfully aid the fabrication of porous HA samples. In this investigation, comparison of physical and mechanical characteristics between samples prepared using difference techniques was made.
This study was conducted based on the hypothesis that mineral and physicochemical properties of cockle shells similarly resemble the properties of corals (Porites sp.). Hence, the mineral and physicochemical evaluations of cockle shells were conducted to support the aforementioned hypothesis. The results indicated that cockle shells and coral exoskeleton shared similar mineral and physicochemical properties.
The incorporation of magnesium ions into the calcium phosphate structure is of great interest for the development of artificial bone implants. This paper investigates the preparation of magnesium-doped biphasic calcium phosphate (Mg-BCP) via sol gel method at various concentrations of added Mg. The effect of calcinations temperature (ranging from 500 degrees C to 900 degrees C) and concentrations of Mg incorporated into BCP has been studied by the aid of XRD, TGA and infrared spectroscopy (IR) in transmittance mode analysis. The study indicated that the powder was pure BCP and Mg-BCP with 100% purity and high crystallinity. The results also indicated that beta-tricalcium phosphate (beta-TCP) phase can be observed when the powder was calcined at 800 degrees C and above.
A novel hydrothermal process has been developed various hydroxyapatite(HA) powder. The HA powder was investigated in different calcination temperatures over the range of 200 degrees C-800 degrees C. TG/DTA and XRD analysis revealed that at temperatures of 700-800 degrees C the decomposition processes and phase changes took place. It is due to the appearance of TCP phase substituting the HA phase. FESEM observation showed that the produced hydroxyapatite powder was extraordinarily fine with nanosize primary particles and almost evenly spherical in shaped. Its high purity proved that the powder fulfills medical requirement.
The sintering behaviour of synthesized HA powder that was calcined at various temperatures ranging from 700 degrees C to 1000 degrees C was investigated in terms of phase stability, bulk density, Young's modulus and Vickers hardness. The calcination treatment resulted in higher crystallinity of the starting HA powder. Decomposition of HA phase to form secondary phases was not observed in all the calcined powders. The results also indicated that powder calcination (up to 900 degrees C) prior to sintering has negligible effect on the sinterability of the HA compacts. However, powder calcined at 1000 degrees C was found to be detrimental to the properties of sintered hydroxyapatite bioceramics.
The effect of Manganese (Mn) addition on the Vickers hardness and relative density of nanocrystalline hydroxyapatite (HA) dense bodies were studied. The starting Mn doped HA powders was synthesized via sol-gel method with Mn concentration varies from 2 mol% up to 15 mol% Mn. The Mn doped HA disc samples were prepared by uniaxial pressing at 200MPa and subsequently sintered at 1300 degrees C. Characterization was carried out where appropriate to determine the phases present, bulk density, Vickers hardness of the various content of Mn doped HA dense bodies. The addition of Mn was observed to influence the color appearance of the powders and dense bodies as well. Higher Mn concentration resulted in dark grey powders. It was also found that the hardness and relative density of the material increased as the Mn content increased and influenced by the crystallinity of the prepared Mn doped HA powders.
A middle-aged lady presented with a three-month history of chronic cough. After a long and extensive investigation, CT thorax revealed collapse consolidation of the right lower lung lobe and bronchoscopy showed a polypoidal tumour within the involved bronchus. Thoracotomy and segmental lung resection revealed a peanut in the airways of the fibrotic and infected lung tissue. In view of the rarity of the food particle aspiration in a healthy adult, the delay in presentation and diagnosis in our patient, we would like to highlight this particular case. A high index of suspicion of FBA is necessary to avoid unnecessary anxiety, extensive investigations and overzealous treatment as well as to promote lung conservation.
Inverted papillomas (IPs), although histologically benign, are aggressive lesions that may recur after excision. They usually present as unilateral firm, bulky, red and vascular masses. The objective of this case series is to discuss the surgical treatment options for IPs and to review the literature with a special emphasis on our experience with endoscopic medial maxillectomy. A retrospective review of the data of patients with IP treated by endoscopic medial maxillectomy was performed. This report describes the surgical experience with five patients with IP arising from various sites on the lateral nasal wall. Data points collected included age, sex, location(s) and histopathological diagnosis (benign IP vs IP with dysplasia or carcinoma). The surgical treatment strategy, need for adjunct approaches, complications, recurrence rates and length of follow-up were determined. The average age was 51.2 years (range, 35-62 years), with four males and one female. All cases were managed with endoscopic medial maxillectomy as the primary surgical modality. Adjunctive approaches included endoscopic dacryocystorhinostomy (EDCR) in two patients who presented with epiphora post-operatively. Intra-operative frozen section was performed in all cases to ensure complete tumor removal. No intra-operative complications were encountered. No recurrences were noted in these patients, with a mean follow-up period of 23 months.