On the potential activity of hyaluronic acid as an antimicrobial agent: experimental and computational validations.

This century has seen the rise of antibiotic resistance as a significant public health problem. In addition, oxidative stress may also be a factor in selecting resistant strains of bacteria. The current study analyzed microbially produced hyaluronic acid's antibacterial activity and antioxidant activity. It had significant antibacterial action against strains of Staphylococcus aureus and Escherichia coli, with the IC50 value obtained being 487.65 µg mL-1 for antioxidant assay. Our molecular docking investigations of hyaluronic acid on tyrosyl-tRNA synthetase (Staphylococcus aureus: -6.13 kcal/mol, Escherichia coli: -5.79 kcal/mol) and topoisomerase II DNA gyrase (Staphylococcus aureus: -5.02 kcal/mol, Escherichia coli: -4.90 kcal/mol) confirmed the ligands' possible binding mode to the appropriate targets' sites. We also employed molecular dynamics simulation and showed that HA binds more strongly with 1JIL (-85.455 ± 12.623 kJ/mol) compared to 2YXN (-49.907 ± 64.191 kJ/mol), 5CDP (-47.285 ± 13.925 kJ/mol), and 6RKS (-45.306 ± 21.338 kJ/mol). We also report that the ligand forms several hydrogen bonds in molecular simulation, implying regular interaction with key residues of the enzymes. The results in this study indicate the potential use of HA in the vast field of applications having both asthetic and medicinal values.

Seasonal variations of dengue vector mosquitoes in rural settings of Thiruvarur district in Tamil Nadu, India.

BACKGROUND & OBJECTIVES: Mosquitoes are vectors of several important vector-borne diseases (VBDs) like malaria, dengue, chikungunya, Japanese encephalitis (JE) and lymphatic filariasis (LF). Globally, these VBDs are of major public health concern including India. The information on vector mosquitoes from Thiruvarur district in Tamil Nadu state remains largely either unknown or undocumented. The present study was, therefore, undertaken to find out the seasonal variation in mosquitoes with special reference to dengue vectors in rural areas of Thiruvarur district, Tamil Nadu, India. METHODS: Surveillance of immature vector mosquitoes was undertaken from March 2018 to February 2019. The emerged adults were identified to find out the composition of mosquito species prevalent in the district. The seasonal variations of the mosquitoes especially dengue vectors were analysed for summer (March-July) spring (August-November) and winter (December-February) seasons in all the blocks of Thiruvarur district. RESULTS: A total of 4879 mosquitoes emerged from the immature collection and the species identification revealed the prevalence of both vector and non-vector species. Five important mosquito vectors collected were -Aedes albopictus, Ae. aegypti, Culex tritaeniorhynchus, Cx. gelidus, and Cx. quinquefasciatus. Other mosquito species collected were Lutzia fuscana, Anopheles barbirostris, An. subpictus, and Armigeres (Armigeres) subalbatus. During the spring season, the dengue vectors showed high indices of breateau index (BI), ranging from 16 to 120; besides, container index (CI) ranging from14.29 to 68.57 and pupal index (PI) from 53.33 to 295 among the study blocks. The major breeding sites were discarded plastic containers, discarded tyres, open sintex tanks (water storage tanks), cement tanks, discarded fibre box, pleated plastic sheets, tree holes, bamboo cut stumps, coconut spathe, and coconut shells. INTERPRETATION & CONCLUSION: The immature vector surveillance revealed seasonal variations in the entomological indices of Aedes breeding potential. The high indices observed indicate high Aedes breeding density and, therefore, a higher risk for dengue/chikungunya outbreaks in rural areas of Thiruvarur district. The present finding warrants intensive surveillance and follow up vector control measures to avert outbreaks and prevent vector-borne diseases. Health education and the community participation in awareness camps prior to monsoon and societal commitment will help in strengthening source reduction, anti-larval operations and anti-adult measures to tackle vector-borne diseases especially dengue.

Predictive ability of urinary biomarkers for outcome in children with acute kidney injury.

BACKGROUND: Urinary neutrophil gelatinase-associated lipocalin (NGAL), N-acetyl-beta-D-glucosaminidase (NAG), and interleukin 18 (IL-18) were found to be useful for early detection of acute kidney injury (AKI). The objective of this study was to determine the predictive ability of biomarkers for mortality and variation in levels in relation to different stages of AKI, need for dialysis, etiologies, and with duration of hospital stay. METHODS: Urinary NGAL, NAG, and IL-18 levels were measured in 50 children with AKI and 30 age- and gender-matched healthy controls. AKI was classified as per pediatric Risk, Injury, Failure, Loss, and End-stage (RIFLE) criteria. RESULTS: Median NGAL, NAG, and IL-18 values were significantly increased in AKI patients compared with controls (p < 0.001), with significant increase among risk, injury, and failure stages. Nonsurvivors had significantly higher median levels of NGAL (p = 0.008) and NAG (p = 0.018) than survivors. NGAL had highest area under the curve (AUC) at 0.750 [confidence interval (CI) 0.580-0.920], followed by NAG at 0.724 (CI 0.541-0.907), with sensitivity and specificity of 75 % each; and IL-18 (AUC 0.688, CI 0.511-0.864), with sensitivity 62.5 % and specificity 70.8 %, for predicting mortality. Values were significantly higher in patients who required peritoneal dialysis (PD) than in those in whom it was not indicated. Levels were comparable among different etiologies. Only NGAL level was found to be a significant risk factor associated with longer duration of hospital stay. CONCLUSIONS: Urinary NGAL and NAG had modest predictive ability for mortality. Children requiring dialysis had significantly raised levels, and the NGAL level had significant association with duration of hospital stay.

Toll-like receptor 3 (TLR-3), TLR-4 and CD80 expression in peripheral blood mononuclear cells and urinary CD80 levels in children with idiopathic nephrotic syndrome.

BACKGROUND: The aims of this study were (1) to detect toll-like receptor (TLR)-3, TLR-4 and CD80 expression in peripheral blood mononuclear cells (PBMCs) and estimate urinary CD80 levels in children with idiopathic nephrotic syndrome and (2) to investigate the utility of these markers to differentiate between biopsy-proven minimal change disease (MCD) and focal segmental glomeruloscelerosis (FSGS). METHODS: The study included 70 patients with idiopathic nephrotic syndrome (NS), of whom 40 had steroid-sensitive NS (SSNS; 25 with active NS, 15 in remission) and 30 had steroid-resistant NS (SRNS) patients, and 23 healthy controls. TLR-3, TLR- 4 and CD80 mRNA expression levels in PBMCs were determined and the urinary CD80 level estimated. RESULTS: Median TLR-3, TLR-4 and CD80 mRNA expression levels were higher in patients with active SSNS than in those with SRNS, and the latter patient group also had significantly lower expression levels than the controls. The expression levels of these markers were associated with reductions in remission. Patients with biopsy-proven MCD had higher median expression levels of these markers than those with FSGS, but the differences were not statistically significant. Median urinary CD80/creatinine values were significantly higher in patients with SSNS and SRNS than in the controls and steroid-sensitive patients in remission (p < 0.001). CD80 levels were also significantly higher in patients with MCD than in those with FSGS (p = 0.002). A cut-off level of >914.5 ng/g had a sensitivity of 86.6%, specificity 71.4% and area under the curve of 0.828 (95% confidence interval 0.678-0.978, p = 0.002) for the diagnosis of MCD. CONCLUSIONS: Increased expressions of TLR-3, TLR-4 and CD80 mRNA and the level of urinary CD80/creatinine could be useful markers to differentiate patients of SSNS in relapse from those with SRNS. Further these markers can also distinguish biopsy proven MCD from FSGS in SRNS patients.

Strategies on process engineering of chondrocyte culture for cartilage tissue regeneration.

The current work is an attempt to study the strategies for cartilage tissue regeneration using porous scaffold in wavy walled airlift bioreactor (ALBR). Novel chitosan, poly (L-lactide) and hyaluronic acid based composite scaffold were prepared. The scaffolds were cross-linked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, N-hydroxysuccinimide and chondroitin sulfate to obtain interconnected 3D microstructure showing excellent biocompatibility, higher cellular differentiation and increased stability. The surface morphology and porosity of the scaffolds were analyzed using scanning electron microscopy (SEM) and mercury intrusion porosimeter and optimized for chondrocyte regeneration. The study shows that the scaffolds were highly porous with pore size ranging from 48 to 180 µm and the porosities in the range 80-92%. Swelling and in vitro degradation studies were performed for the composite scaffolds; by increasing the chitosan: HA ratio in the composite scaffolds, the swelling property increases and stabilizes after 24 h. There was controlled degradation of composite scaffolds for 4 weeks. The uniform chondrocyte distribution in the scaffold using various growth modes in the shake flask and ALBR was studied by glycosaminoglycans (GAG) quantification, MTT assay and mixing time evaluation. The cell culture studies demonstrated that efficient designing of ALBR increases the cartilage regeneration as compared to using a shake flask. The free chondrocyte microscopy and cell attachment were performed by inverted microscope and SEM, and from the study it was confirmed that the cells uniformly attached to the scaffold. This study focuses on optimizing strategies for the culture of chondrocyte using suitable scaffold for improved cartilage tissue regeneration.

A combination of complexation and self-nanoemulsifying drug delivery system for enhancing oral bioavailability and anticancer efficacy of curcumin.

OBJECTIVE: Curcumin, the golden spice from Indian saffron, has shown chemoprotective action against many types of cancer including breast cancer. However, poor oral bioavailability is the major hurdle in its clinical application. In the recent years, self-nanoemulsifying drug delivery system (SNEDDS) has emerged as a promising tool to improve the oral absorption and enhancing the bioavailability of poorly water-soluble drugs. In this context, complexation with lipid carriers like phospholipid has also shown the tremendous potential to improve the solubility and therapeutic efficacy of certain drugs with poor oral bioavailability. METHODS: In the present investigation, a systematic combination of both the approaches is utilized to prepare the phospholipid complex of curcumin and facilitate its incorporation into SNEDDS. The combined use of both the approaches has been explored for the first time to enhance the oral bioavailability and in turn increase the anticancer activity of curcumin. RESULTS: As evident from the pharmacokinetic studies and in situ single pass intestinal perfusion studies in Sprague-Dawley rats, the optimized SNEDDS of curcumin-phospholipid complex has shown enhanced oral absorption and bioavailability of curcumin. The cytotoxicity study in metastatic breast carcinoma cell line has shown the enhancement of cytotoxic action by 38.7%. The primary tumor growth reduction by 58.9% as compared with the control group in 4T1 tumor-bearing BALB/c mice further supported the theory of enhancement of anticancer activity of curcumin in SNEDDS. CONCLUSION: The developed formulation can be a potential and safe carrier for the oral delivery of curcumin.

Studies on process optimization methods for rapamycin production using Streptomyces hygroscopicus ATCC 29253.

Rapamycin is a high-value product finding immense use as a drug, in organ transplantation, and as a potential immunosuppressant. Optimization of fermentation parameters of rapamycin production by Streptomyces hygroscopicus NRRL 5491 has been carried out. The low titer value of rapamycin in the original producer strain limits its applicability at industrial level. This study aims at improving the production of rapamycin by optimizing the nutrient requirements. Addition of L-lysine increased the production of rapamycin up to a significant level which supports the fact that it acts as precursor for rapamycin production, as found in previous studies. Effect of optimized medium on the Streptomyces growth rate as well as rapamycin production has been studied. The optimization study incorporates one at a time parameter optimization studies followed by tool-based hybrid methodology. This methodology includes the Plackett-Burman design (PBD) method, artificial neural networks (ANN), and genetic algorithms (GA). PBD screened mannose, soyabean meal, and L-lysine concentrations as significant factors for rapamycin production. ANN was used to construct rapamycin production model. This strategy has led to a significant increase of rapamycin production up to 320.89 mg/L at GA optimized concentrations of 25.47, 15.39, and 17.48 g/L for mannose, soyabean meal, and L-lysine, respectively. The present study must find its application in scale-up study for industrial level production of rapamycin.

Graphene-silymarin-loaded chitosan/gelatin/hyaluronic acid hybrid constructs for advanced full-thickness burn wound management.

Burn wounds (BWs) with extensive blood loss, along with bacterial infections and poor healing, may become detrimental and pose significant rehabilitation obstacles in medical facilities. Therefore, the freeze-drying method synthesized novel hemocompatible chitosan, gelatin, and hyaluronic acid infused with graphene oxide-silymarin (CGH-SGO) hybrid constructs for application as a BW patch. Most significantly, synthesized hybrid constructs exhibited an interconnected-porous framework with precise pore sizes (≈118.52 µm) conducive to biological functions. Furthermore, the FTIR and XRD analyses document the constructs' physiochemical interactions. Similarly, enhanced swelling ratios, adequate WVTR (736 ± 78 g m-2 hr-1), and bio-degradation rates were seen during the physiological examination of constructs. Following the in vitro investigations, SMN-GO added to constructs improved their anti-bacterial (against E.coli and S. aureus), anti-oxidant, hemocompatible, and bio-compatible characteristics in conjunction with prolonged drug release. Furthermore, in vivo, implanting constructs on wounds exhibited significant acceleration in full-thickness burn wound (FT-BW) healing on the 14th day (CGH-SGO: 95 ± 2.1 %) in contrast with the control (Gauze: 71 ± 4.2 %). Additionally, contrary to gauze, the in vivo rat tail excision model administered with constructs assured immediate blood clotting. Therefore, CGH-SGO constructs with an improved porous framework, anti-bacterial activity, hemocompatibility, and biocompatibility could represent an attractive option for healing FT-BWs.

In vitro and in vivo assessment of curcumin-quercetin loaded multi-layered 3D-nanofibroporous matrix prepared by solution blow-spinning for full-thickness burn wound healing.

Burn wounds (BWs) cause impairment of native skin tissue and may cause significant microbial infections that demand immediate care. Curcumin (Cur) and quercetin (Que) exhibit antimicrobial, hemocompatibility, ROS-scavenging, and anti-inflammatory properties. However, its instability, water insolubility, and low biological fluid absorption render it challenging to sustain local Cur and Que doses at the wound site. Therefore, to combat these limitations, we employed blow-spinning and freeze-drying to develop a multi-layered, Cur/Que-loaded gelatin/chitosan/PCL (GCP-Q/C) nanofibroporous (NFP) matrix. Morphological analysis of the NFP-matrix using SEM revealed a well-formed multi-layered structure. The FTIR and XRD plots demonstrated dual-bioactive incorporation and scaffold polymer interaction. Additionally, the GCP-Q/C matrix displayed high porosity (82.7 ± 2.07 %), adequate pore size (∼121 µm), enhanced water-uptake ability (∼675 % within 24 h), and satisfactory biodegradation. The scaffolds with bioactives had a long-term release, increased antioxidant activity, and were more effective against gram-positive (S. aureus) and gram-negative (E. coli) bacteria than the unloaded scaffolds. The in vitro findings of GCP-Q/C scaffolds showed promoted L929 cell growth and hemocompatibility. Additionally, an in vivo full-thickness BW investigation found that an implanted GCP-Q/C matrix stimulates rapid recuperation and tissue regeneration. In accordance with the findings, the Gel/Ch/PCL-Que/Cur NFP-matrix could represent an effective wound-healing dressing for BWs.