Effective-Insecticide Repellent Synergy Against Mosquito Vectors Of Malaria

The mosquitoes responsible for malaria transmission to humans belong to the Anopheles genus. One of the best known and most extensively studied is Anopheles gambiae, Africa’s principal malaria vector. The protection recommended by the World Health Organization for people at risk from this devastating disease is the use of mosquito nets impregnated with pyrethroids, of low toxicity for mammals and highly active against mosquitoes. Unfortunately, excessive and inappropriate use of this family of insecticide, particularly by spraying, has induced a disturbing rise in the number of resistant individuals in the Anopheles populations. The mosquito nets treated with pyrethroids can therefore lose their effectiveness. It is therefore essential to devise new control strategies against these malaria vectors that are resistant to these insecticides.
IRD researchers and their partners (1) obtained encouraging results by combining a non-pyrethroid insecticide, propoxur, and a repellent, N,N-diethyl toluamide (DEET). They based their investigations on previous work which had revealed a strong synergy between the two components. A combination of the two had proved to be much more effective than the straightforward addition of their respective properties. Mosquito nets soaked with this mixture had a lethal power and irritant effect that inhibited the mosquitoes from biting. Moreover, the mosquitoes are hit by a powerful paralysing action, known as the “knockdown” effect (3), on contact with the mixture. The mortality rates determined were satisfactory, in that they equalled those obtained by using deltamethrin, a commonly-used synthetic pyrethroid, highly effective against mosquitoes.
The researchers tested two mixtures composed of a non-pyrethroid insecticide of the organophosphate family, combined with either a standard repellent, DEET, or with a new-generation synthetic repellent. Both of these mixtures show a strong synergy in the resulting lethal and paralysing effects on the mosquitoes. However, only the association between the insecticide and the standard repellent produced a synergistic effect that inhibited the mosquito from taking its blood feed. A synergistic effect was also observed with regard to the treatment’s residual efficacy which is several months longer than that of either agent applied alone. The advantage of the synergistic property of these combinations is enhanced by the fact that it significantly reduced the necessary effective doses against the mosquitoes (about 6 times that of the insecticide applied alone), to attain an efficacy equivalent to that of deltamethrin.
The nets treated with the two mixtures in the laboratory were subsequently tested in field trials, in the rice-growing area 40 km North of Bobo-Dioulasso, in Burkina Faso. This area has the specificity of harbouring two different forms of Anopheles gambiae. The first appears in May and June in the rice-fields. It shows no resistance to pyrethroids. The second emerges in September and October in puddles left by monsoon rains. These do show resistance to these insecticides. As expected, the usual pyrethroid-treated nets turned out to be effective only against non-resistant mosquitoes of the first population. Conversely, the nets pre-soaked with non-pyrethroid-repellent combinations proved excellent protection for the people of the local villages, whatever the population of mosquitoes present. Nevertheless, their residual efficacy (about 15 days) in real conditions did not match the researchers’ expectations. The team consequently envisage working in conjunction with a company able to devise a system for encapsulating the mixture to prolong the residual life of treated mosquito nets.

DNA Damage In A New Light

It has long been known that UV light can damage DNA, reducing its ability to replicate and interact with proteins, and often resulting in the development of skin cancers. However, not much is known about how the elasticity of DNA strands is altered upon exposure to UV light. Now a group of researchers at Duke University have developed a method to measure changes in the mechanical properties of DNA upon irradiation with UV light.
Piotr Marszalek and his colleagues have conducted single-molecule force spectroscopy measurements on viral DNA, which show the unraveling of the DNA double helix upon exposure to UV irradiation. The researchers essentially pick up individual DNA molecules with the tip of a scanning probe microscope and stretch it while measuring the forces generated. These "stretch-release" measurements enable the accurate determination of changes in the elasticity of the DNA strands. Upon exposure to UV light, the force profile of the viral DNA changes dramatically in a dose-dependent manner. The force curve of intact DNA is characterized by a plateau region. This characteristic plateau is drastically reduced in width with increasing exposure to UV light.
UV light induces the crosslinking of the constituent DNA bases within the polynucleotide chains, as well as causes the formation of lesions by linking together the adjacent strands. The small changes in structure induced by this crosslinking can very profoundly affect the ability of DNA to recognize specific molecules, and can thus completely disrupt its ability to replicate and interact with the transcriptional machinery to synthesize proteins. Marszalek and his colleagues have also examined synthetic DNA to figure out the extent to which different bases are affected by UV light. They conclude that the changes in the force profile of viral DNA exposed to UV light are due to the local unwinding of the double helix in some regions arising from the massive formation of crosslinked structures.
"These are the first measurements that establish a relationship between DNA nanomechanics and damage", said Marszalek. He believes that this work paves the way for using stretch-release force spectroscopy measurements in DNA diagnostics.

Innovative Treatment Option Holds Promise For Millions Of People World Wide Suffering From Excessive Sweating

An estimated 3 percent of the world population, or about 197 million people suffer from some form of hyperhidrosis (excessive sweating), many of whom do not receive proper diagnosis or treatment. Hyperhidrosis is a medical condition in which the body sweats three to four times the normal amount. This can lead to undue embarrassment, social and psychological problems, and in the most severe cases, impede normal day-to-day functions. The exact cause of hyperhidrosis is unknown, but researchers have linked it to over activity of the nerves that send signals to the sweat glands in the skin.
This condition typically affects any of the following areas: the palms (palmar hyperhidrosis), the underarms (axillary hyperhidrosis), the face (facial hyperhidrosis), or the feet (plantar hyperhidrosis). Treatment for hyperhidrosis depends on the area of the body affected, but in general consists of the following options: topical and oral medications, iontophoresis, botulinum toxin (Botox) injections, and when these nonsurgical options have proven ineffective - surgery.
Researchers at Barrow Neurological Institute in Phoenix analyzed the outcome of 300 consecutive patients undergoing bilateral sympathectomy for hyperhidrosis between May 1996 and April 2005. One hundred and twenty-nine patients presented with palmar hyperhidrosis, 11 with axillary hyperhidrosis, and 160 with both axillary and palmar hyperhidrosis. The mean age of patients was 27.9. Average follow-up was 10.3 months (range 0.5-36) and obtained either in the clinic, by phone or by written questionnaire.
The results of this study, Biportal Thoracoscopic Sympathectomy for Hyperhidrosis: Experience with 300 Patients, was presented by Gregory Lekovic, MD, PhD, JD, 5:00 to 5:10 p.m. on Tuesday, April 17, 2007, during the 75th Annual Meeting of the American Association of Neurological Surgeons in Washington, D.C. Co-authors are Scott Wait, MD, Kathy J. Kenny, RN, MS, and Curtis A. Dickman, MD.
Advances in technology now enable sympathectomy surgery to be performed thorascopically, using a minimally invasive procedure in which a tiny fiberoptic camera and small surgical instruments are inserted through three small incisions (usually less than half an inch). The nerves that cause the excessive sweating are identified by the camera and then cut. After one side is completed, the identical procedure is performed on the opposite side.
In the 300 patients in this research study, the following outcomes were noted:
– Complete resolution of palmar and axillary hyperhidrosis was seen in 99.3 percent and 61 percent of patients, respectively.
– Serious intraoperative complications included two arrythmias (asystole requiring cardioversion in one patient, bradycardia that resolved without treatment or sequelae in one patient) and postoperative depression in one patient.
– Nine patients had postoperative pneumothorax ( accumulation of air or gas in the pleural cavity) , of which five required chest tube drainage.
– An additional four patients required prophylactic chest tube drainage due to pleural adhesions.
– Severe compensatory hyperhidrosis affected 16 patients. Compensatory hyperhidrosis is typically the most common side effect following surgery. Although patients may no longer sweat excessively in their hands, underarms and/or feet, they often will sweat more in another part of the body, such as the chest, back or legs .
– Seven patients developed Horner’s syndrome. Horner’s syndrome results from inadvertent damage to nerves above those that were cut. This can result in decreased facial sweating, drooping of the eyelid and decreased pupil size on the same side of the body where the nerves were inadvertently injured. Sometimes these symptoms are reversible over a period of weeks to months, but in other cases, may be permanent.
– Six patients were affected by intercostal neuralgia, which is pain caused by damage to the nerves located between the ribs.
"Thoracoscopic sympathectomy is an effective and low-morbidity treatment for patients suffering from severe palmar and axillary hyperhidrosis, in particular when other treatment options have not alleviated the symptoms," said Dr. Lekovic.
Founded in 1931 as the Harvey Cushing Society, the American Association of Neurological Surgeons (AANS) is a scientific and educational association with more than 6,800 members worldwide. The AANS is dedicated to advancing the specialty of neurological surgery in order to provide the highest quality of neurosurgical care to the public. All active members of the AANS are certified by the American Board of Neurological Surgery, the Royal College of Physicians and Surgeons (Neurosurgery) of Canada or the Mexican Council of Neurological Surgery, AC. Neurological surgery is the medical specialty concerned with the prevention, diagnosis, treatment and rehabilitation of disorders that affect the entire nervous system, including the spinal column, spinal cord, brain and peripheral nerves.

The Effect Of Male Circumcision On Sexuality

UroToday.com- There has been suggestion and debate about whether circumcision affects sexual sensation of the penis but there have been few relevant studies to examine this possible consequence of the procedure. South Korea has one of the highest circumcision rates in the world and most are not performed in the neonatal period. This allows a unique opportunity to examine the effect of adult circumcision on sexuality. A prospective study was performed to compare men who were circumcised or not, and to compare the sex lives of men before and after circumcision. The study, by D. Kim and M.G. Pang from Gyungki-Do Korea, is published in the March 2007 issue of BJU International.
The study included 373 sexually active men aged 30-57 years of whom 255 were circumcised (mean age 37.1 years) and 118 were not (mean age 38.2 years). Of the 255 circumcised men, 138 were sexually active before circumcision, and all were circumcised after the age of 20 years. To address the effects of circumcision on the quality of sex life, including masturbation, a modified Brief Male Sexual Function Inventory (BMSFI) which included additional questions about whether sex life and masturbatory pleasure had improved or worsened after circumcision.
Analysis of the results showed that there were no significant differences in sexual drive, erection, ejaculation and ejaculatory latency time between circumcised and uncircumcised men. Masturbatory pleasure decreased after circumcision in 48% of the respondents, while 8% reported increased pleasure. Masturbatory difficulty increased after circumcision in 63% of the respondents but it was easier in 37%. About 6% answered that their sex lives improved, while 20% reported a worse sex life after circumcision.
This study suggests that adult circumcision adversely affects sexual function in a significant number of men, and the authors suggest that it may be due to loss of nerve endings in the removed skin. In addition, there was an approximately 9% incidence of severe penile scarring or uncomfortable erections from curvature or tethering after circumcision.

New Tortillas Better For Dieters and Diabetics

People with dieting blues should try swapping white corn tortillas for blue. A recent study suggests that the coloured flatbreads are healthier, especially for diabetics and dieters, Sara Jensen reports in Chemistry & Industry, the magazine of the SCI.
Scientists in Mexico, home of the taco, found that tortillas made from blue corn had less starch and a lower glycæmic index than their white counter parts. They also found that the blue tortillas had 20% more protein than white (Journal of the Science of Food and Agriculture, DOI 10.1002/jsfa.3008).
The glycæmic index (GI) ranks carbohydrates according to their effects on blood glucose levels. Foods with a lower GI are considered healthier as they slowly release sugar into the bloodstream. This reduces fluctuations in our blood glucose and insulin levels, helping to maintain a steady supply of energy. Low GI foods are said to have long-term health benefits, reducing your risk of heart disease and diabetes as well as aiding and maintaining weight loss.
Juscelino Tovar, an author of the study, said that one important benefit of the lower GI blue tortillas is their potential role in preventing or controlling metabolic syndrome, a combination of disorders which increase the risk of heart disease, stroke and diabetes.
NB The blue colouring is due to the presence of anthocyanins in the corn. These are the same health promoting compounds found purple berries and red wine.
—————————-Article adapted by Medical News Today from original press release.—————————-
About Chemistry & IndustryChemistry & Industry magazine from SCI delivers news and comment from the interface between science and business. As well as covering industry and science, it focuses on developments that will be of significant commercial interest in five- to ten-years time. Published twice-monthly and free to SCI Members, it also carries authoritative features and reviews. Opinion-formers worldwide respect Chemistry & Industry for its independent insight.
About SCI SCI is a unique international forum where science meets business on independent, impartial ground. Anyone can join, and the Society offers a chance to share information between sectors as diverse as food and agriculture, pharmaceuticals, biotechnology, environmental science and safety. As well as publishing new research and running events, SCI has a growing database of member specialists who can give background information on a wide range of scientific issues. Originally established in 1881, SCI is a registered charity with members in over 70 countries.
About the Journal of the Science of Food and AgricultureThe Journal of the Science of Food and Agriculture (JSFA) publishes peer-reviewed original research and critical reviews in these areas, with particular emphasis on interdisciplinary studies at the agriculture/food interface. This international journal covers fundamental and applied research.
JSFA is an SCI journal, published by John Wiley & Sons, on behalf of the Society of Chemical Industry, and is available in print (ISSN: 0022-5142) and online (ISSN: 1097-0010) via Wiley InterScience http://www.interscience.wiley.com/ For further information about the journal go to http://interscience.wiley.com/jsfa
About WileyJohn Wiley & Sons, Ltd., based in Chichester, England, is the largest subsidiary of John Wiley & Sons, Inc. Founded in 1807, John Wiley & Sons, Inc. provides must-have content and services to customers worldwide. Their core businesses include scientific, technical, and medical journals, encyclopedias, books, and online products and services; professional and consumer books and subscription services; and educational materials for undergraduate and graduate students and lifelong learners. Wiley has publishing, marketing, and distribution centres in the United States, Canada, Europe, Asia, and Australia. The company is listed on the New York Stock Exchange under the symbols JWa and JWb. Wiley’s recently re-launched Internet site can be accessed at http://www.wileyeurope.com/
Source: Lisa RichardsSociety of Chemical Industry

Diabetes Ethnic Minorities Lose Out In The UK

Patients from ethnic minorities are not only more likely to suffer from diabetes, but also receive lower quality care from the National Health Service (NHS), claims a paper published in the online open access journal, International Journal for Equity in Health.
Michael Soljak, together with colleagues from Imperial College, London, UK, investigated the treatment received in 2002 by 21,343 diabetic patients in three North West London Primary Care Trusts (PCTs): Ealing, Hammersmith & Fulham, and Hounslow. The researchers also compared the patients’ general health, shown by factors such as blood pressure and cholesterol levels, and diabetes control, to the patients’ treatment.
General practitioners (GPs) were encouraged to record new patients’ ethnicity by providing training and support to the practices. Of the diabetic patients in the three PCTs, 70 percent had a valid ethnicity code, obtained through patient questionnaires and entered by practice staff.
The authors found that although diabetes control was worse among the South Asian population, a smaller proportion of South Asians were prescribed insulin. They also found that although the White population studied was older, blood pressure differences between the groups were small, indicating poorer control in non-White ethnic groups.
The poorer quality of care for Asian diabetic patients could be explained by patient factors- such as poor understanding of the disease - or by the standard of care their GPs offered. Institutional racism is unlikely to be a major cause, as many South Asian patients are registered with GPs from their own ethnic group.
“This study highlights the need to capture ethnicity data in clinical trials and in routine care, to specifically investigate the reasons for these ethnic differences. But we don’t just need to know more about both the practice and patient factors involved,” says Soljak, “there should be more intensive management of diabetes and education about the disease in South Asian patients. The best option would be trials comparing different types of such interventions. Our study also shows that in future these trials can be carried out using routinely collected clinical information.”
Ethnic inequalities in the management and outcome of diabetes in three English Primary Care TrustsMichael Soljak, Azeem Majeed, Joseph Eliahoo and Anne DornhorstInternational Journal for Equity in Healthhttp://www.equityhealthj.com/
BioMed Central is an independent online publishing house committed to providing open access to peer-reviewed biological and medical research. This commitment is based on the view that immediate free access to research and the ability to freely archive and reuse published information is essential to the rapid and efficient communication of science.
BioMed Central currently publishes over 170 journals across biology and medicine. In addition to open-access original research, BioMed Central also publishes reviews, commentaries and other non-original-research content. Depending on the policies of the individual journal, this content may be open access or provided only to subscribers.

New Call For Research Proposals-Diabetes UK

We are calling for research proposals aimed at ‘Improving the day-to-day management of diabetes’.
This call is based on the results of the research priorities survey we conducted earlier this year, which was open to everyone and proved to be the biggest consultation we have ever run.
The new call for proposals has been approved by Diabetes UK’s Board of Trustees. They agreed that they should consider research that would change the ‘here and now’ aspects of diabetes and address quality of life issues.
Research themes included in this call for proposals include:
– prevention and avoidance of complications– prevention and treatment of diabetes using diet and exercise– refinement of existing technologies.
Diabetes UK will particularly welcome proposals in the area of prevention and avoidance of hypoglycaemia.
Diabetes UK will commit £6 million of funds raised over the next few years to support research to improve the day-to-day management of diabetes and is seeking to fund ambitious, innovative, multi-centre collaborative research programmes whose outcomes will make a huge difference to the daily lives of people with diabetes. No funding limit has been set for individual projects.
Applications will be assessed on:
– the potential of the research to make a real difference to the lives of people with diabetes– scientific excellence– calibre of the applicants– value for money.
Outline application forms and further particulars are available to download on the right.
Closing date for receipt of outline applications: 12 noon on Tuesday 4 September 2007.
http://www.diabetes.org.uk