Durgeshwer Singh

Chitin membranes containing silver nanoparticles for wound dressing application

Silver nanoparticles are gaining importance as an antimicrobial agent in wound dressings. Chitin is a biopolymer envisioned to promote rapid dermal regeneration and accelerate wound healing. This study was focused on the evaluation of chitin membranes containing silver nanoparticles for use as an antimicrobial wound dressing. Silver nanoparticles were synthesised by gamma irradiation at doses of 50 kGy in the presence of sodium alginate as stabiliser. The UV–Vis absorption spectra of nanoparticles exhibited an absorption band at 415–420 nm, which is the typical plasmon resonance band of silver nanoparticles. The peaks in the X‐ray diffraction (XRD) pattern are in agreement with the standard values of the face‐centred cubic silver. Transmission electron microscopy (TEM) images indicate silver nanoparticles with spherical morphology and small particle size in the range of 3–13 nm. In vitro antimicrobial tests were performed using Pseudomonas aeruginosa and Staphylococcus aureus to determine the antimicrobial efficiency of the chitin membranes containing 30, 50, 70 and 100 ppm nanosilver. No viable counts for P. aeruginosa were detected with 70 ppm silver nanoparticles dressing after 1‐hour exposure. A 2‐log reduction in viable cell count was observed for S. aureus after 1 hour and a 4‐log reduction after 6 hours with 100 ppm nanosilver chitin membranes. This study demonstrates the antimicrobial capability of chitin membranes containing silver nanoparticles. The chitin membranes with 100 ppm nanosilver showed promising antimicrobial activity against common wound pathogens.

Radiation sterilization of tissue allografts: A review

Tissue substitutes are required in a number of clinical conditions for treatment of injured and diseased tissues. Tissues like bone, skin, amniotic membrane and soft tissues obtained from human donor can be used for repair or reconstruction of the injured part of the body. Allograft tissues from human donor provide an excellent alternative to autografts. However, major concern with the use of allografts is the risk of infectious disease transmission. Therefore, tissue allografts should be sterilized to make them safe for clinical use. Gamma radiation has several advantages and is the most suitable method for sterilization of biological tissues. This review summarizes the use of gamma irradiation technology as an effective method for sterilization of biological tissues and ensuring safety of tissue allografts.

Polyvinyl pyrrolidone/carrageenan blend hydrogels with nanosilver prepared by gamma radiation for use as an antimicrobial wound dressing.

Hydrogels were prepared using polyvinyl pyrrolidone (PVP) blended with carrageenan by gamma irradiation at different doses of 25 and 40 kGy. Gel fraction of hydrogels prepared using 10 and 15% PVP in combination with 0.25 and 0.5% carrageenan was evaluated. Based on gel fraction, 15% PVP in combination with 0.25% carrageenan and radiation dose of 25 kGy was selected for the preparation of hydrogels with nanosilver. Radiolytic synthesis of silver nanoparticles within the PVP hydrogel was carried out. The hydrogels with silver nanoparticles were assessed for antimicrobial effectiveness and physical properties of relevance to clinical performance. Fluid handling capacity (FHC) for PVP/carrageenan was 2.35 ± 0.39–6.63 ± 0.63 g/10 cm2 in 2–24 h. No counts for Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Candida albicans were observed in the presence of hydrogels containing 100 ppm nanosilver after 3–6 h. The release of silver from hydrogels containing 100 ppm nanosilver was 20.42 ± 1.98 ppm/100 cm2 in 24 h. Hydrogels containing 100 ppm nanosilver with efficient FHC demonstrated potential microbicidal activity (≥3 log10 decrease in CFU/ml) against wound pathogens, P. aeruginosa, S. aureus, E. coli, and C. albicans. PVP/carrageenan hydrogels containing silver nanoparticles can be used as wound dressings to control infection and facilitate the healing process for burns and other skin injuries.

Sterilization of bone allografts by microwave and gamma radiation

Abstract Purpose: Bone allografts are used to enhance healing in osteotomies, arthrodesis, fractures and to replace bone loss resulting from tumour or trauma. However, a major concern associated with the bone allografts is the potential for disease transmission. Various sterilization techniques have been developed to prevent infection through allografts. This study was undertaken with the aim of exploring the use of microwave radiation for sterilization of bone allografts and to compare with gamma radiation sterilization. Materials and methods: Bone allografts were processed from femoral heads obtained from living donors. The effect of microwave and gamma radiation on the bacteria isolated from bone allograft was evaluated. The microwave radiation treatment was performed at 2450 MHz (frequency) for varying lengths of time at maximum power 900 Watts (W). Viability of three Gram-positive bacteria – Bacillus subtilis, Corynebacterium, Staphylococcus aureus and three Gram-negative bacteria – Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa was examined after irradiation of bacterial suspensions and contaminated processed bone allografts. The sterility test of microwave and gamma irradiated bone allograft was carried out in accordance with ISO (International Organization for Standardization) 11737-2. Results: Microwave irradiation (2450 MHz and 900 W) of bacterial isolates resulted in complete inactivation within 60 seconds. The contaminated bone samples showed no growth of organisms after 2 minutes of exposure to microwave irradiation. No viable counts were detected in bone grafts inoculated with Gram-negative bacterial species on gamma irradiation to a dose of 15 kGy. Bones contaminated with Gram-positive bacteria required a higher dose of 20 kGy for complete inactivation. Conclusions: The study shows that sterilization of contaminated femoral head bone allografts can be achieved by short exposure of 2 min to 2450 MHz and 900 W microwave radiation.

Use of gamma-irradiated amniotic membrane for the healing of split skin graft donor site

The management of split skin graft donor site is targeted towards promoting the healing process, while minimizing adverse effects and complications. The aim was to study the efficacy of gamma-irradiated amniotic membrane dressing for the healing of split skin graft donor site. Amniotic membranes isolated from the placenta were processed and sterilized by gamma radiation. Thirty patients with split skin graft donor site were included in the study. The average age of the patients was 33.33±16.45 years in study group and 38.93±18.52 years in control group. The average ulcer size was 92.8±66.2 cm2 in study group and 82.5±56.0 cm2 in control group. Processed amniotic membranes were applied just after taking split skin graft. Split skin graft donor site was assessed on day 8 and 12 for epithelialization, pain during change of dressing, discharge from donor site, status of healing and any adverse reactions. Significant (p < 0.0001) reduction in pain during change of amniotic membrane dressing as compared to conventional dressing was observed. The average per day rate of epithelialization on split skin graft donor site was 10.31% in the study group and 7.31% in the control group (p > 0.05). Significant (p < 0.001) enhancement in the healing of donor site was observed with amniotic membrane dressing as compared to the paraffin gauze dressing. The patients with processed gamma-irradiated amniotic membrane experienced no pain during change of dressing and improved epithelialization.

Ethno-veterinary practices of goat farmers in tarai region of Uttarakhand

A survey was carried out on 645 goat farmers in Udham Singh Nagar and Nainital districts of Uttarakhand from April, 2015 to March, 2017. The information on the common symptoms or ailments inflicting losses to the goats along with the use of local plants and other traditional healthcare practices followed by them were collected through personal interview using a wellstructured questionnaire. It was found that ethno-veterinary practices used by the farmers for diarrhoea/dysentery, pneumonia, anoestrus, bloat, retention of placenta, gastrointestinal helminthiasis, external parasites, constipation, indigestion, wounds and plant poisonings are common ailments in goats. Different types of plant species and their parts viz., roots, leaves, twigs, bark powder, fruits, seeds, oils etc. are used for the treatment of these ailments. Ethno-veterinary practices like bolus made from pigeon droppings and sprouted Triticum for aneostrous goats, feeding cotton seeds for enhancing growth, oral administration of a mixture of asafoetida, Chirayata swertia, Trachyspermum ammi and black salt for bloat, feeding a paste of Curcuma longa, Trachyspermum ammi and black salt for fever and pneumonia, feeding castor (Ricinus communis) seeds for constipation were evaluated.

Assessment of pre and post-incubation parameters in Uttara breeder hens

A study was conducted to determine the effects of pre-incubation egg parameters on post-incubation parameters in Uttara breeder hens. A total of 2,890 hatching eggs were classified according to three egg weight groups viz. small (44-52 g); medium (53-57 g) and large (58-68 g). Results indicated that large-sized eggs produced chicks with higher hatch-weight than medium and small-sized eggs. However, no differences were observed for fertility and hatchability rates but significant differences were found for chick quality and chick weight. It was therefore concluded from the results of the present study that sorting of eggs by weight prior to incubation might be advantageous in producing uniform size hatchlings to meet specific market demands with focus on breeding for obtaining maximum number of saleable chicks.

Application of molecular markers to find out classificatory determinants of rice ( Oryza sativa L.)

The present communication is aimed to find out determinants of molecular marker based classification of rice (Oryza sativa L) germplasm using the available data from an experiment conducted for development of molecular fingerprints of diverse varieties of Basmati and non Basmati rice adapted to irrigated and aerobic agro-eco systems. The distance-matrix based dendrogram was developed following UPGMA method that grouped all the 44 varieties agro-eco systems wise. We examined the clustering of Basmati and non- Basmati varieties in detail. The results suggest that the easily distinguishable simple characters viz. plant height, photosensitivity, leaf color, awn’s color, awns’ number etc., governed by major genes did not contribute significantly towards classification of rice genotypes used. The complex characters such as adaptation to agro-eco systems and rice quality may play vital role in determination of molecular marker based classification of rice genotypes. Key word: Basmati rice, molecular markers, genetic diversity, agro-eco systems, rice quality

Multivariate analysis for evaluation and classification of toria germplasm accessions

Multivariate analysis was carried out with 22 agro-morphological traits in 92 germplasm accessions of toria [Brassica rapa (L.) var. toria]. Principal factor analysis identified eight principal components which explained about 62% variability. PC 1 had 15.04% of total variation in agro-morphological traits; PC 2 depicted 8.55% of total morphological variability, while PC 3 accounted for 7.68% of the total variation. Varimax rotation enabled loading of similar type of variables on a common principal factor permitting to designate them as seed yield, maturity, leaf and siliqua characters and oil content factors. The germplasm accessions TC 5, TC 36, TC 59, TC 86 and TC 87 were found to be superior on the basis of principal factor scores with regard to seed yield, its main components and oil content when both the principal factors were considered together. These accessions may further be utilized in breeding programmes for evolving toria varieties/populations with high seed yield and superior oil content. Hierarchical cluster analysis categorized all the 92 accessions into 10 clusters containing one to 35 accessions. Based on the inter-cluster distances, maximum genetic diversity was observed between C VIII and C X (87.16) followed by C VI and C X (86.22), C VII and C X (85.84) and C III and C VII (84.57) indicating that germplasm accessions from these clusters can usefully be hybridized for getting superior recombinants in segregating generations. The results of cluster and principal factor analyses were in corroboration.

Pre-plant weed control for a palmarosa (Cymbopogon martinii) nursery

Studies initiated during the nursery growing seasons (MayJuly) 1987 and 1988 at the Central Institute of Medicinal and Aromatic Plants, Lucknow(India), indicated the usefulness ofpre-sowing irrigation in stimulating weed seed germination and minimizing competition in a palmarosa nursery. With three pre-sowing irrigations (5 cm depth each), sufficient to keep soil moist (above 60% available moisture) for 15 d, c. 70% of the totalnon-dormant weed seeds present in the soilgerminated and resulted in a corresponding decrease in weed numbers and dry weight, estimated at the end of the nursery growing period (40 d after sowing). Weed numbers and dry weightwere reduced by 86% and 98%, respectively, compared to unweeded control, when three pre-sowing irrigations were supplemented with one hand weeding at 10 days after sowing. Production of palmarosa seedlings and their growth and dry matter accumulation with three pre-sowing irrigations plus one hand weeding treatment was similar to the hand weeded control (three ...