Showing papers by "Chandana Haldar published in 2013"

Development of ciprofloxacin hydrochloride loaded poly(ethylene glycol)/chitosan scaffold as wound dressing

Abstract: A novel ciprofloxacin hydrochloride loaded chitosan/poly(ethylene glycol) (PEG) composite scaffold was developed for wound dressing application PEG incorporation in chitosan scaffold showed enhanced loading up to 54 % and increased cumulative release of the drug up to 35 % as compared to pure chitosan scaffold (20 %) The drug loading and control release of the drug has been explained by the morphological features and drug–polymer/polymer–polymer interactions revealed by SEM, FTIR and DSC Bacterial growth inhibition evaluation using Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus confirmed the efficacy of released drug from the scaffolds (pure and PEG mixed chitosan) Swelling study, bacterial penetration, moisture vapour transmission rate, haematocompatibility and biodegradation profile supported the suitability of scaffold used as wound dressing materials In-vivo study on mice finally validated the controlled rate of drug release showing the effectiveness of PEG incorporation into the scaffold for quicker and regulated wound healing

Biodegradable Polymers for Potential Delivery Systems for Therapeutics

Abstract: Biodegradable polymers are being extensively used with great interest in areas of nanobiotechnology such as drug delivery, diagnostics, and other applications for clinical and biomedical research covering cardiovascular diseases, diabetes, osteogenesis, cancer, and tissue engineering. Various biodegradable polymers such as poly(lactic acid), poly(lactic-co-glycolic acid), poly (e-caprolactone), chitosan, gelatin, and poly(alkyl cyanoacrylates) have been extensively utilized as polymeric materials and devices for targeted cellular and tissue-specific clinical applications to achieve maximal therapeutic efficacy with minimal or no side effects. Recently, polymeric nanoparticles have revolutionized the area of nanobiotechnology by creating new opportunities for advancing medical science and disease treatment. Polymeric nanoparticles have the potential to act as a carrier of drugs and active constituents to targeted sites, protecting them from the environment and controlling their release rates, thereby enhancing their biological activity and decreasing the adverse side effects. This article compiles updated information regarding various biodegradable polymers, methods of preparation of biodegradable polymeric nanoparticles, and their application in therapeutic and diagnostic strategies for various diseases. This article will support research scientists and clinical physicians who are interested in the development and application of biodegradable polymeric nanoparticles as potential delivery systems for therapeutics.

Photoperiodic induced melatonin regulates immunity and expression pattern of melatonin receptor MT1 in spleen and bone marrow mononuclear cells of male golden hamster.

Abstract: The pineal gland transduces day length information into chemical signal of melatonin that ultimately translates photic stimulus into season-specific immune responses to promote survival of individual from incidence of opportunistic diseases. To date, the immune adjustments being a result of photoperiodic exposures for any nocturnal seasonally breeding rodent have not been systematically examined. Therefore, we evaluated the humoral and cell mediated immune responses of photoperiodically entrained male golden hamsters. Short day induced melatonin increased the immune parameters such as spleen mass, total leukocyte (TLC) and lymphocyte count (LC), proliferation of splenocytes, peripheral blood mononuclear cells (PBMCs) and bone marrow mononuclear cells (BMMNCs) along with serum IL-2 and anti-Keyhole Limpet Hemocyanin (KLH) IgG production when compared with long day experienced hamsters. Short term melatonin treatment (for two weeks) to long day hamsters enhanced to some extent the proliferation of splenocytes, PBMC and TLC/LC. We also localized the melatonin membrane receptor MT1 in spleen and BMMNCs that strongly supported our western blot analysis for the expression of MT1 in spleen suggesting that different photoperiodically induced circulatory melatonin is responsible for the immunomodulation. Therefore, photoperiod can influence the peripheral melatonin level to improve immune responses of hamsters according to season for better survival.

The oxidative damages caused by ultraviolet radiation type C (UVC) to a tropical rodent Funambulus pennanti: role of melatonin.

Abstract: Data suggests that UV radiation causes oxidative damage of the cells due to the release of inflammatory cytokines which in turn generates reactive oxygen species (ROS) that damages lipids, proteins and DNA. On the other hand, melatonin a potent antioxidant from the pineal gland under most of the conditions acts as a free radical scavenger. Our data suggests that melatonin pre-treatment (s.c. injections) significantly protected the diurnal squirrels from oxidative damages caused by UVC irradiation of 1528 mJ cm(-2) that induced suppression of delayed type hypersensitivity (DTH) responses. It also protected the rodents from UVC radiation induced increase in thiobarbituric acid reactive substances (TBARS) levels in spleen accompanied with a significant decrease in Superoxide Dismutase (SOD) activity indicating the occurrence of superoxide anion mediated damages following UVC exposure. Melatonin administration reduced the radiation induced oxidative stress in the spleen tissue as analyzed by reduced lipid damages and higher SOD activity. Under in vivo (100 μg/100g body wt.) and in vitro (250 pg/10(6) cells) conditions, melatonin pre-treatment prevented spleen tissues and splenocytes from radiation induced cell death. In conclusion we may suggest that melatonin could be one of the potent antioxidant and radio protector that may reduce UV radiation induced toxicity to the cells and hence may be clinically important.

Reciprocal interaction between melatonin receptors (Mel1a, Mel1b, and Mel1c) and androgen receptor (AR) expression in immunoregulation of a seasonally breeding bird, Perdicula asiatica: Role of photoperiod

Abstract: Light is the major environmental stimulus affecting behaviour and physiology of avian species. Our study elaborates the photoperiodic regulation of melatonin (Mel 1a, Mel 1b , and Mel 1c ) and androgen receptor (AR) to elucidate its reciprocal interaction in regulation of general immunity in tropical wild bird, Perdicula asiatica . Effect of different photoperiodic exposures such as continuous light (LL), continuous dark (DD), long days (LD; 16 h light/day), short days (SD; 10 h light/day) and normal day length (NDL) was accessed both on cellular and humoral immune parameters like per cent stimulation ratio (%SR), total leukocyte count (TLC), leukocyte count (LC), plasma interleukin-2 (IL-2), tumor necrosis factor-alpha (TNF-α), spleen and gonad weight, plasma melatonin, and testosterone level as well as their receptor expression on spleen and testis. Expression of melatonin receptor, Mel 1a and Mel 1b in spleen was high in SD experiencing bird as compared to LD birds. In all photoperiodic groups, AR expression was upregulated in spleen. In addition, our reverse transcription polymerase chain reaction (RT-PCR) results support differentially localized mRNA Mel 1b and Mel 1c expression in spleen and testis. In sum, photoperiodically modulated level of melatonin via reciprocal regulation of Mel 1a , Mel 1b , and Mel 1c, and AR in spleen as well as in testis modulates immunity, suggesting a compensatory mechanism between reproduction and immunity in a seasonally breeding bird, P. asiatica .

Adaptive and Ecological Significance of the Seasonal Changes in Hematological, Biochemical and Hormonal Parameters in the Tropical Goat Capra Hircus

Abstract: The neuroendocrine system, through which animals integrate environmental changes and decide when to reproduce, to grow and to store energy, plays a major role in adaptation to the environment. Adaptation of any vertebrate in general and ruminants in particular are influenced by climatic changes being maximally exposed to nature. Elaborating adaptive significance of ruminants in response to season-dependent ecological stresses, we selected the best window i.e., study of variations in blood biochemistry which is totally lacking for goats. Our objective was to find the season- and gender-dependent variations of blood biochemistry at (i) metabolic (glucose, cholesterol, protein, %hemoglobin) (ii) hormonal (testosterone, estrogen, progesterone, melatonin) (iii) hematological (total leucocytes count- TLC; differential leukocyte count- DLC) and, finally, (iv) oxidative load of blood (superoxide dismutase-SOD; catalase, malondialdihyde- MDA) in the goat Capra hircus during three different seasons (summer, winter and monsoon). Compared to summer significant changes were noted at metabolic level during monsoon and winter as those seasons provide for inflammatory and cold stress. Cholesterol and glucose levels were high in females than males during all three seasons. Irrespective of sexes, serum protein was highest during winter while testosterone was high irrespective of seasons; hence, males were sexually active throughout the year. Estrogen was high only during the onset of winter (October, heat phase) making the female goats short-day breeders. Melatonin, a neurohormone, regulating reproduction and immunity, was highest in winter (short days) and low during summer and monsoon. Hematological parameters were lowest during summer (long days). Blood oxidative load was high during monsoon and winter due to season-bound infections that induce oxidative stress. High metabolic and immune parameters were noted during winter and monsoon which suggest an adaptive significance in tropical goats against ecological stress induced by low temperature of winter and pathogenic invasion occurring while grazing during monsoon.

Daily variations in plasma melatonin and melatonin receptor (MT1), PER1 and CRY1 expression in suprachiasmatic nuclei of tropical squirrel, Funambulus pennanti

Abstract: The suprachiasmatic nucleus (SCN) plays a major role in photoperiodic regulation of seasonal functions by modulating the melatonin signal. To date no report exists regarding the role of the ambient photoperiod in the regulation of melatonin receptor MT1 and clock gene (PER1 and CRY1) expression in the SCN of any tropical rodent that experiences the least variation in the photoperiod. We noted the expression of MT1, PER1 and CRY1 in the SCN of a tropical squirrel, Funambulus pennanti, along with the plasma level of melatonin over 24 h during the reproductively active (summer) and inactive (winter) phases. The seasonal day length affected the peripheral melatonin, which was inversely related with the MT1 expression in the SCN. The timing for peak expression of PER1 was the same in both phases, while the decline in PER1 expression was delayed by 4 h during the inactive phase. The CRY1 peak advanced by 4 h during the active phase, while the interval between the peak and decline of CRY1 remained the same in both phases. It can be suggested that seasonally changing melatonin levels modulate MT1 expression dynamics in the SCN, altering its functional state, and gate SCN molecular “clock” gene profiles through changes in PER/CRY expression. Such a regulation is important for photo-physiological adaptation (reproduction/immunity) in seasonal breeders.