Comparison of membrane immobilized zero-valent iron nanoparticles for RED ME4BL azodye degradation

Textile industries are hailed as one of the major environmental polluters in the world, owing to their release of undesirable dye effluents. Synthetic dyes do not adhere to fabric firmly and are released into the aquatic ecosystem as effluent. Consequently, the consistent release of wastewater from numerous textile industries without previous treatment has detrimental effects on the ecosystem and human health.   Treatment methods currently being used fail to degrade the dye effluents and have their own shortcomings. Immobilized nanoparticles have been extensively studied for dye remediation because of their many advantages over conventional methods. The present study aimed to compare the efficiency of two different carrier matrices [namely Poly(vinylidene fluoride) and Polyurethane] for iron nanoparticle and their decolorization activity on an azo dye (RED ME4BL). Scanning Electron Microscopy was carried out to show the deposition of iron nanoparticles on the membrane. The reaction kinetics of the bare nanoparticles were compared with that of the immobilized nanoparticles, and all were found to follow pseudo-second-order kinetics. Polyurethane immobilized iron nanoparticles showed a significant degradation of RED ME4bl than the Poly(vinylidene fluoride) immobilized iron and bare nanoparticles. This paper also demonstrates a relatively newer method for nanoparticle immobilisation using the synthetic polyurethane form.

Cellular reparative mechanisms of mesenchymal stem cells for retinal diseases

The use of multipotent mesenchymal stem cells (MSCs) has been reported as promising for the treatment of numerous degenerative disorders including the eye. In retinal degenerative diseases, MSCs exhibit the potential to regenerate into retinal neurons and retinal pigmented epithelial cells in both in vitro and in vivo studies. Delivery of MSCs was found to improve retinal morphology and function and delay retinal degeneration. In this review, we revisit the therapeutic role of MSCs in the diseased eye. Furthermore, we reveal the possible cellular mechanisms and identify the associated signaling pathways of MSCs in reversing the pathological conditions of various ocular disorders such as age-related macular degeneration (AMD), retinitis pigmentosa, diabetic retinopathy, and glaucoma. Current stem cell treatment can be dispensed as an independent cell treatment format or with the combination of other approaches. Hence, the improvement of the treatment strategy is largely subjected by our understanding of MSCs mechanism of action

Production, optimization and characterisation of chitosanase of Bacillus sp. and its applications in nanotechnology

Chitosanases is a class of enzymes which hydrolyse chitosan, a natural biopolymer consisting of d-glucosamine in various degrees. In this study, chitosanase producing Bacillus sp. was isolated from soil sample. Chitosanase production was optimized using response surface methodology and the produced chitosanase was characterized. The crude enzyme was found to possess antibacterial and antifungal activity. Chitosanase enzyme was used for trimming chitosan based polymeric nanoparticles produced using sodium trimetaphosphate chelator. Chitosanase enzyme was also utilized for synthesis of silver nanoparticles which were then characterized by UV–Vis, FTIR, SEM, TEM and AFM. The produced nanoparticles were checked for antibacterial and antifungal activity

The 'checkmate' for iron between human host and invading bacteria: chess game analogy

Iron is an essential nutrient for all living organisms with critical roles in many biological processes. The mammalian host maintains the iron requirements by dietary intake, while the invading pathogenic bacteria compete with the host to obtain those absorbed irons. In order to limit the iron uptake by the bacteria, the human host employs numerous iron binding proteins and withholding defense mechanisms that capture iron from the microbial invaders. To counteract, the bacteria cope with the iron limitation imposed by the host by expressing various iron acquisition systems, allowing them to achieve effective iron homeostasis. The armamentarium used by the human host and invading bacteria, leads to the dilemma of who wins the ultimate war for iron

Misunderstanding of leptospirosis

Leptospirosis is an emergent zoonosis implicating major health concern in developing countries, especially in tropical regions with frequent flooding (Watson et al., 2007). Leptospiral infections are rapidly onset and have long incubation periods of up to 28 days. Such long incubation of Leptospires leads to difficulty in identification of the medical condition as an infection-based disease, and was once misidentified as a host self-immune disorder by the clinicians. After decades of incidents, leptospirosis was first reported in 1886 as infectious disease, and Leptospira was identified as the causative bacteria in 1916 (Inada, 1908; Weil, 1886). Much confusion and misunderstanding surround the diagnosis and prevention of leptospirosis have contributed to the delayed treatment and poor prognosis

Development of self-repair nano-rod scaffold materials for implantation of osteosarcoma affected bone tissue

Osteosarcoma is the most widely recognized fatal bone disease in children and young adults. The osteosarcoma affected places of bone implant materials lose their activity after a period of time due to the possibility of regenerating sarcoma cells. Hence, the complete recovery of this disease is very challenging. Subsequently, new helpful methodologies, including natural antioxidant loaded bone implant materials, are effectively used to treat osteosarcoma cells. In this regard, nano-hydroxyapatite reinforced with a xylitol based poly(xylitol sebacate) PXS co-polymer together with a capsaicin loaded scaffold was investigated on osteosarcoma cells. The physicochemical properties of the scaffold were evaluated by FT-IR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), TEM (transmission electron microscopy), and XRD (X-ray diffraction). The in vitro release and antioxidant activity of the capsaicin loaded nHAP/PXS/CAP scaffold were evaluated by UV-Visible spectroscopy. Cytotoxicity against the Saos-2 cancer line and cell viability in the osteoblast cell MG63 are reported. Eventually, the composite enlarges the creation of reactive oxygen species (ROS) in Saos-2 cells

Distribution and prevalence of microorganisms causing diabetic foot infection in Hospital Serdang and Hospital Ampang for the year 2010 to 2014

Background: In developing countries like Malaysia, the prevalence of diabetes mellitus is increasing at an alarming rate. Various complications develop in patients diagnosed with diabetes. Diabetic foot is one such complication that is a threat to morbidity and mortality rate owing to its risk of amputation. Understanding the microbiology of diabetic foot infection becomes an essential part of management as it can help to channel the exact treatment rather than empirical treatment. Aim: To determine the distribution and prevalence of microorganism causing diabetic foot infection in Hospital Serdang and Hospital Ampang for the year 2010 till 2014. Methodology: This was a cross-sectional study using retrospective data from January 2010 to December 2014 of 885 patients with diabetic foot infection in Hospital Serdang and Hospital Ampang, tertiary hospitals in Klang Valley. Data were analyzed using IBM SPSS Statistics version 22.0 for Windows. Results: A total of 1356 pathogens were isolated from 885 patients, with a rate of 1.53 isolates per culture (IPC). The prevalence of gram-negative bacteria was predominant in DFI accounting for 71.27% whereas gram-positive was only 28.73%. Among the gram-negative isolates, the most common pathogen was Pseudomonas aeroginosa accounting for 24.49% followed by Proteus mirabilis (14.34%) and Klebsiella spp. (11.12%). Gram-positive isolates consist of Staphylococcus aureus with a percentage of 66.77% and Streptococcus spp. 33.23%. The Methicillin-Resistant Staphylococcus aureus (MRSA) accounts for 26.24% of the isolates. There were more monomicrobial cultures than polymicrobial culture (465 vs. 420). The most common antibiotic prescribed is ampicillin/sulbactam (55.57%) followed by cloxacillin (13.29%) and penicillin (10.77%). Conclusion: The prevalence of gram-negative bacteria in DFI is higher than gram-positive bacteria. The most common gram-negative bacteria is Pseudomonas aeroginosa followed by Proteus mirabilis and Klebsiella spp. whereas the most common gram-positive bacteria is Staphylococcus aureus. The rate of monomicrobial infection is slightly higher than polymicrobial infection. Ampicillin/sulbactam is the most commonly prescribed antibiotic for a patient with DFI

Hypoxia in bone and oxygen releasing biomaterials in fracture treatments using mesenchymal stem cell therapy: a review

Bone fractures have a high degree of severity. This is usually a result of the physical trauma of diseases that affect bone tissues, such as osteoporosis. Due to its highly vascular nature, the bone is in a constant state of remodeling. Although those of younger ages possess bones with high regenerative potential, the impact of a disrupted vasculature can severely affect the recovery process and cause osteonecrosis. This is commonly seen in the neck of femur, scaphoid, and talus bone. In recent years, mesenchymal stem cell (MSC) therapy has been used to aid in the regeneration of afflicted bone. However, the cut-off in blood supply due to bone fractures can lead to hypoxia-induced changes in engrafted MSCs. Researchers have designed several oxygen-generating biomaterials and yielded varying degrees of success in enhancing tissue salvage and preserving cellular metabolism under ischemia. These can be utilized to further improve stem cell therapy for bone repair. In this review, we touch on the pathophysiology of these bone fractures and review the application of oxygen-generating biomaterials to further enhance MSC-mediated repair of fractures in the three aforementioned parts of the bone

Design of polymeric materials for culturing human pluripotent stem cells: progress toward feeder-free and xeno-free culturing

This review describes recent developments regarding the use of natural and synthetic polymers to support the propagation of human pluripotent stem cells (hPSCs), human embryonic stem cells (hESCs), and induced pluripotent stem cells (hiPSCs) while maintaining pluripotency in feeder-free and xeno-free cultures. The development of methods for culturing these cells without using mouse embryonic fibroblasts (MEFs) as a feeder layer will enable more reproducible culture conditions and reduce the risk of xenogenic contaminants, thus increasing the potential clinical applications of differentiated hPSCs. Human or recombinant fibronectin, laminin-511, and vitronectin, which are components of the extracellular matrix (ECM), have been used instead of Matrigel for the feeder-free growth of undifferentiated hPSCs. Successful hPSC cultures have been described for the following conditions: on oligopeptide-immobilized surfaces derived from vitronectin, on microcarriers prepared from synthetic polymers, and encapsulated within three-dimensional (3D) hydrogels composed of alginate and other hydrophilic natural polymers. Recently, synthetic biomaterials that allow hPSCs to maintain pluripotency by secreting endogenous ECM components have been designed. The combination of human ECM proteins or cell adhesion molecules (e.g., oligopeptides and poly-d-lysine) and synthetic biomaterials with well-designed surfaces and/or structures (e.g., scaffolds, hydrogels, microcarriers, microcapsules, or microfibers) in the presence of a chemically defined medium containing recombinant growth factors would offer a xeno-free alternative to feeder cells for culturing hPSCs and maintaining their pluripotency

A low prevalence of inducible macrolide, lincosamide, and streptogramin B Resistance phenotype among methicillin-susceptible staphylococcus aureus isolated from Malaysian patients and healthy individuals

Background: Antibiotic resistance among Staphylococcus aureus is of great concern worldwide. This resistance is further complicated by the ability of S. aureus to confer cross-resistance to other antibiotics due to the presence of resistance genes, such as erythromycin resistance methylase (erm) genes, which render the bacterium resistant to macrolide-lincosamide-streptogramin B (MLSB) antibiotics. Resistance to these antibiotics can lead to therapeutic failure, resulting in significant morbidity and mortality in patients with S. aureus infections. Objectives: This study was performed to examine the distribution of MLSB-resistant strains of methicillin-susceptible S. aureus (MSSA), which were obtained from hospitalized patients and normal healthy individuals (carriers) using phenotypic methods, such as the double-disk diffusion (D-test) and the genotypic method by polymerase chain reaction (PCR). Methods: A total of 183 nonduplicative MSSA isolates obtained from hospitalized patients (133) and carriers (50) in our previous studies were randomly selected for the D-test. The guidelines of the Clinical and Laboratory Standards Institute (CLSI) were used for the interpretation of the results of this test. The detection of ermA, ermB, ermC and msrA genes by PCR was performed for isolates that had positive D-test results and that were resistant to erythromycin. Results: Of the 183 MSSA isolates, 97.2% and 98.4% were highly susceptible to erythromycin and clindamycin, respectively. MSLB resistance was detected in four isolates (2.2%). Of the 133 MSSA isolated from hospitalized patients, only 3.0% (4/133) and 2.3% (3/133) exhibited resistance to erythromycin and clindamycin, respectively. With regard to the MLSB resistance phenotypes, only 1.6% and 0.6% exhibited inducible MLSB (iMLSB) and MS phenotypes, respectively. The ermC gene was detected in all three iMLSB phenotypes, and the msrA gene was detected in the MS phenotype. Surprisingly, all MSSA isolates (100%) from carriers exhibited extremely high susceptibility to both antibiotics. Conclusions: The prevalence rates of iMLSB MSSA isolates vary according to geographical locations and the local antibiotic policy. The low prevalence rate of iMLSB MSSA isolates could probably be related to the judicious use of antibiotics for treating S. aureus infections in our studied population. Nonetheless, continuous antibiotic surveillance is still necessary to control any emergence of resistance isolates so that targeted therapy and effective control can be implemented accordingly