Fine structure of the alimentary canal of the larval blow fly <Emphasis Type="Italic">Chrysomya megacephala</Emphasis> (Diptera: Calliphoridae)

Morphology of the alimentary canal of the mature third instar larva of the blow fly, Chrysomya megacephala (F.), was examined using light, scanning, and transmission electron microscopy. Salivary structures consist of a single median deferent duct that bifurcates into efferent ducts connected to paired, tubular salivary glands comprised of closely packed conical-shaped epithelial cells with large nuclei. The crop occurs as a large, swollen diverticulum of the digestive tube and is lined internally with convoluted cuticle (epicuticle and endocuticle). The esophagus is a simple, straight tube internally lined with cuticle and externally encompassed by muscle fibers. The cardia is a bulb-like structure composed of anterior foregut tissue and posterior midgut tissue from which the peritrophic membrane (PM) is produced. The midgut begins within the cardia which is flanked posteriorly by four tubular gastric caeca that are lined internally with four to five layers of cuboidal epithelial cells bearing microvilli. Midgut tissue is lined with simple cuboidal epithelium whose cells are filled with numerous secretory granules and possessed long microvilli facing the lumen. A peritrophic membrane is contained within the midgut lumen. The larval hindgut consists of the pylorus, Malpighian tubules, ileum, colon, rectum, and anus, posteriorly. The pylorus is characterized by a single layer of epithelial cells encircled by a muscular layer and the presence of PM within the lumen. Malpighian tubules each diverge into two tubular structures totalling four long tubules of long chained cuboidal cells bearing microvilli internally. The wall of the ileum is comprised primarily of a monolayer of cuboidal epithelial cells with large oval nuclei and more intense muscular fibers surrounding the periphery. A cuticular layer surrounds the lumen containing the PM. This inner cuticle consists of a thin epicuticle that is electron-dense; whereas, the endocuticle is much thicker but less electron-dense. Myo-epithelial cells are dense in the anal region, where the PM persists.     

Feroniellin B, a new highly potent human platelet aggregation inhibitor from Feroniella lucida

Human platelet aggregation inhibition by coumarins isolated from Feroniella lucida roots extract was investigated. Of 11 coumarins examined, feroniellin B highly inhibited platelet aggregation induced by ADP with an IC(50) value of 0.287 mm while the standard drug ibuprofen displayed this inhibition with an IC(50) value of 11.2 mm. The presence of feroniellin B is possibly linked to the ethnopharmacological use of F. lucida as a remedy for cardiovascular diseases.     

Benefit of “transparent soft-short-hood on the scope” for colonoscopy among experienced gastroenterologists and gastroenterologist trainee: a randomized,controlled trial

Background  

The attachment of a transparent hood to the colonoscope tip has been reported to offer some benefits, such as enabling the endoscopist to perform the colonoscopy more easily and to save time. However, there have been no randomized, controlled trials concerning these benefits, nor have any reports been published regarding the use of hoods for the purpose of training colonoscopists. Therefore, we conducted this study to evaluate the possible benefits of the transparent soft short hood when used by both experienced and trainee endoscopist groups.     

Dengue knowledge and practices and their impact on Aedes aegypti populations in Kamphaeng Phet, Thailand

A knowledge, attitude, and practice (KAP) survey and an extensive entomologic survey were conducted in two sub-districts of Kamphaeng Phet province, Thailand, to test the hypothesis that correct dengue knowledge and practice reduce dengue vector populations. We found a negative association between respondents' knowledge of preventive measures and the number of unprotected containers in and around their houses. Knowledge of development sites was positively associated with unprotected containers. No relationships existed between knowledge of dengue and adult mosquito reduction practices. A higher number of unprotected containers increased the likelihood of the house being infested with one or more adult Aedes aegypti. Surprisingly, houses of respondents that used mosquito coils or had screening on doors and windows were significantly more likely to be infested (odds ratio =2.0) with adult Ae. aegypti. We conclude that there is a direct link between knowledge on dengue prevention and container protection practices, whereas measures against adult mosquitoes are used only when people experience a mosquito nuisance problem.     

Colonoscopic perforation： A report from World Gastroenterology Organization endoscopy training center in Thailand

AIM： To determine the incidence of colonoscopic perforation （CP）, and evaluate clinical findings, management and outcomes of patients with CP from the World Gastroenterology Organization （WGO） Endoscopy Training Center in Thailand. METHODS： All colonoscopies and sigmoidoscopies performed between 1999 and 2007 in the Endoscopic unit, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok were reviewed. Incidence of CP, patients＇ characteristics, endoscopic information, intraoperative findings, management and outcomes were analyzed. RESULTS： A total of 17357 endoscopic procedures of the colon （13 699 colonoscopies and 3658 flexible sigmoidoscopies） were performed in Siriraj hospital over a 9-year period. Fifteen patients （0.09%） had CP： 14 from colonoscopy and 1 from sigmoidoscopy. The most common site of perforation was in the sigmoid colon （80%）, followed by the transverse colon （13%）. Perforations were caused by direct trauma from either the shaft or the tip of the endoscope （n = 12,80%） and endoscopic polypectomy （n = 3, 20%）. All patients with CP underwent surgical management： primary repair （27%） and bowel resection （73%）. The mortality rate was 13% and postoperative complication rate was 53%. CONCLUSION： CP is a rare but serious complication following colonoscopy and sigmoidoscopy, with high rates of morbidity and mortality. Incidence of CP was 0.09%. Surgery is still the mainstay of CP management.     

Repellent properties of celery, Apium graveolens L., compared with commercial repellents, against mosquitoes under laboratory and field conditions

In our search for new bioactive products against mosquito vectors, we reported the slightly larvicidal and adulticidal potency, but remarkable repellency of Apium graveolens both in laboratory and field conditions. Repellency of the ethanolic preparation of hexane-extracted A. graveolens was, therefore, investigated and compared with those of 15 commercial mosquito repellents including the most widely used, DEET. Hexane-extracted A. graveolens showed a significant degree of repellency in a dose-dependent manner with vanillin added. Ethanolic A. graveolens formulations (10-25% with and without vanillin) provided 2-5 h protection against female Aedes aegypti. Repellency that derived from the most effective repellent, 25% of hexane-extracted A. graveolens with the addition of 5% vanillin, was comparable to the value obtained from 25% of DEET with 5% vanillin added. Moreover, commercial repellents, except formulations of DEET, showed lower repellency than that of A. graveolens extract. When applied on human skin under field conditions, the hexane-extracted A. graveolens plus 5% vanillin showed a strong repellent action against a wide range of mosquito species belonging to various genera. It had a protective effect against Aedes gardnerii, Aedes lineatopennis, Anopheles barbirostris, Armigeres subalbatus, Culex tritaeniorhynchus, Culex gelidus, Culex vishnui group and Mansonia uniformis. The hexane-extracted A. graveolens did not cause a burning sensation or dermal irritation when applied to human skin. No adverse effects were observed on the skin or other parts of the human volunteers' body during 6 months of the study period or in the following 3 months, after which time observations ceased. Therefore, A. graveolens can be a potential candidate for use in the development of commercial repellents that may be an alternative to conventional synthetic chemicals, particularly in community vector control applications.     

Dengue virus infections in the first 2 years of life and the kinetics of transplacentally transferred dengue neutralizing antibodies in thai children

BACKGROUND: Understanding dengue virus infection in children and the kinetics of maternal dengue neutralizing antibodies is essential for effective dengue immunization of children in endemic areas. METHODS: Serum samples from 219 mother-child pairs and 140 children at 3, 6, 9, 12, 18, and 24 months of age from Bangkok, Thailand, were tested for serotype-specific dengue antibodies. Febrile episodes in the children were recorded. RESULTS: Antibodies were found in 97% of cord serum samples and disappeared in 27%, 80%, and 95% of the children by the age of 6, 9, and 12 months, respectively. Geometric mean titers (GMTs) of the antibodies to 4 dengue serotypes decreased to 5.4-15.5 in 6-month-old infants. Eleven of 12 children acquired dengue virus infection at 6 months of age and beyond; 1 had the infection at 3 months of age. Two exhibited undifferentiated febrile illnesses, and 10 had subclinical infections. CONCLUSIONS: Evidence of dengue virus infection and very low GMTs against all dengue serotypes in children at 6 months of age and beyond was demonstrated. There was no evidence that maternal antibodies were harmful to infants. Dengue virus infection rates increase from 12 months of age onward. These data provide information for supporting the optimal age at vaccination.