Laboratory evaluation of pyriproxifen treated bednets on mosquito fertility and fecundity. A preliminary study.

AIM: The study evaluated the effect of pyriproxifen treated bednets on mosquito fertility and fecundity in the laboratory. Pyriproxyfen (insect growth regulator) has been considered as a possible tool for management of pyrethroid resistance in mosquitoes. There are documentations of the effectiveness of pyriproxifen in controlling larval development when applied directly to breeding site. Considerations have been given to the use of pyriproxyfen on bed nets for sterilizing effect on mosquitoes resistant to pyrethroids. METHOD: Groups of mosquitoes (Anopheles stephensi Beech) were exposed to bednet treated with 2% Pyriproxyfen and untreated netting 24 hrs after blood feeding. After oviposition, egg counts were done for each mosquito in the two groups. Larvae emerging from the laid eggs by each mosquito were counted. Three sets of experiments were successful. RESULTS: There was no significant difference in number of eggs laid between the two treatment groups (p=0.177). There was statistically significant difference in the number of laid eggs that hatched between the treatment types (p=0.0061). There was also statistically significant difference in the mean number of eggs that hatched between the experiments (p=0.0013). The mean number of eggs retained in the pyriproxyfen group was higher (70.3) than in the control group (41.6). This difference was not statistically significant with the small sample tested (p=0.08). CONCLUSION: The results suggest that 2% pyriproxyfen on bed nets has no effect on An. stephensi fecundity. Reduced fertility of eggs laid by mosquitoes exposed to pyriproxyfen treated bed nets was observed.

Wound healing activities of methanolic extracts Ocimum gratissimum leaf in Wistar rats - a preliminary study.

The wound healing effect of leaf extracts of Ocimum gratissimum was investigated in adult male Wistar rats. Two groups of adult male Wistar rats, average body weight 170g, had a 2cm by 2cm square wound inflicted on the dorsolateral aspect of their trunk with Paniculus Carnosus removed. Experimental group had their wound dressed with methanolic leaf extracts of Ocimum gratissimum while control group had their wounds dressed with normal saline dressing. All animals had wound dressing done every five days; wound dimension measured and, wound morphometry assessed. Wound biopsy was done by random selection in each group on day 10 and the day of complete re-epithelisation. Routine paraffin wax processing was done, slides stained with haematoxylene and eosin for histological assessment of fibroblast count, neovascularisation and granulation tissue profile. The result revealed significant wound contraction (P<0.05) on day 10 in the experimental group (mean 73.40 +/- 3.30)cm2 compared with the control group (mean 53.50 +/- 4.32)cm2. Histology of the healed scar showed non-significant (P>0.05) decrease in the mean fibroblast count forthe experimental group (83.80 +/- 5.70) relative to fibroblast count of 90.20 +/- 17.90 in the control group. The mean blood vessel count was also non-significantly lowered (P>0.05) in the experimental group (9.20 +/- 1.20) relative to the control group (13.40 +/- 2.40). Granulation tissue histology on day 10 showed denser inflammatory infiltrate as reflected by increased cellularity in the control group relative to that of the experimental group which though appeared adequate was not as dense as the control group. Thus we suggest that the methanolic extracts of O. gratissimum could be a potential wound healing agent due to its ability to enhance wound contraction.

Enhanced wound contraction in fresh wounds dressed with honey in Wistar rats (Rattus Novergicus).

BACKGROUND: Due to reports that honey accelerates wound healing, an investigation on its role in wound contraction in fresh wounds inflicted on wistar rats was carried out. METHOD: Twenty adult male wistar rats had 2cm by 2cm square wound inflicted on their right dorsolateral trunk. They were divided into two groups. The experimental group had their wounds dressed with honey while the control group had normal saline dressing. Wound dressing was done every five days and measurements taken at each dressing. Wound morphology was also assessed. RESULTS: Dressing with honey significantly enhanced percentage wound contraction on day 10 with value of 79.20+/-2.94 compared to control value of 53.50+/-4.32. p=0.0. The mean wound measurement on day 10 reduced significantly in honey group, 1.15+/-0.18 compared to control group 2.38+/-0.28. p=0.002. However, there was no significant difference in fibroblast count per high power field in honey group 68.0+/-2.59 compared to control 90.2+/-17.40, p=0.242. Honey dressing increased mean blood vessel count per high power field, 18.8+/-3.77 albeit non significantly when compared to control value of 13.4+/-2.44, p=0.264. Also honey dressing caused increased granulation tissue formation in wounds dressed with honey compared to control group. CONCLUSION: Our study suggests that honey dressing enhances wound contraction in fresh wounds which is one of the key features of wound healing.

A comparative study of the wound healing properties of honey and Ageratum conyzoides.

The present study investigates the wound healing properties of methanolic extracts of Ageratum conyzoides leaves compared with those of honey. Thirty Wistar rats were randomized into 3 groups of 10 animals each. They were fed with standard rat cubes and Tap water weighed and acclimatized to laboratory conditions for one week. Under anesthesia, each animal had the skin of its dorsolateral flank shaved after which an area of the skin was excised. On achieving haemostasis, the wounds were packed with gauze soaked in the appropriate dressing for each group. Measurement of wound size, and wound biopsies were taken on the 10th day post-wound creation. Together with healed wound samples, these were processed for histology. Fibroblast and blood vessel densities per unit area of wound were determined for the healed wound samples. Histologically, the day 10 Ageratum sections showed fewer inflammatory cells compared with similar honey and Control sections. Also, healed scar sections of wounds dressed with the herb extract showed more fibrosis. Honey and Ageratum caused significant greater wound contraction than controls (p = 0.001 and 0.005 respectively). Healed wounds from the Ageratum group had significantly fewer fibroblasts than honey and controls (p = 0.012 and 0.036 respectively).