Little Malcolm's Swimming Pool

Dead Ringers

2009-12-23T19:46:00.001-08:00

The Women's Auxiliary Balloon Corps

2009-12-23T19:45:00.001-08:00

Mock the Week

2009-12-23T19:43:00.001-08:00

antibiotic-resistant tuberculosis

2009-12-23T12:47:00.001-08:00

Science Daily (December 23, 2009)

Tuberculosis Strain Thrives on Antibiotic

Scientists have identified a strain of antibiotic-resistant tuberculosis that thrives in the presence of rifampin, a front-line drug in the treatment of tuberculosis. The bacterium was identified in a patient in China and is described in a study by researchers at the Johns Hopkins Bloomberg School of Public Health, Chongqing Pulmonary Hospital, Lanzhou University and Fudan University. The researchers determined that the bacteria grew poorly in the absence of the antibiotic rifampin and better in the presence of the drug. They also observed that the patient's condition grew worse with treatment regimens containing rifampin, before being cured with rifampin-free regimens.

The World Health Organization (WHO) estimates that tuberculosis kills approximately 2 million people worldwide each year. Multidrug-resistant tuberculosis (MDR-TB) is becoming an increasing problem in many parts of the world, largely due to poor patient adherence to the six-month tuberculosis chemotherapy. About 5 percent of all TB cases are MDR-TB that is resistant to isoniazid and rifampin, two main drugs used to treat the disease.

"Rifampin-dependent tuberculosis is an unrecognized and potentially serious treatment issue," said Ying Zhang, MD, PhD, senior author of the study and professor in the Bloomberg School's W. Harry Feinstone Department of Molecular Microbiology and Immunology. "Rifampin resistance is ominous. Our study highlights the potential dangers of continued treatment of MDR-TB with rifamycins that occur frequently due to delayed or absent drug susceptibility testing in the field. Further studies are urgently needed to determine how common such rifampin-dependent MDR-TB is in field conditions and if it contributes to the worsening of the disease in MDR patients and treatment failures."

Zhang adds that rifampin-dependent tuberculosis is difficult to detect and may be a bigger problem than we currently realize, since the bacteria do not grow well in the culture medium unless rifampin is added. The study authors urge timely detection of rifampin-dependent or -enhanced bacteria in patients with treatment failure by including rifampin in culture media and removing of rifampin from the treatment regimen once rifampin dependency or enhancement are detected. However, the researchers note that drug susceptibility testing is time-consuming and not easily performed in resource-poor settings where tuberculosis is frequently more common.

For the study, the research team documented the treatment of a 35-year-old Chinese man with tuberculosis. The man failed to respond to the WHO's thrice-weekly treatment regimen, which includes rifampin and other first-line tuberculosis drugs. The patient's condition worsened following an additional treatment regimen with rifampin and other second-line agents. Further testing detected the rifampin-dependency/enhancement. The patient fully recovered once rifampin was removed from his treatment regimen.

Reference:

An interesting case of rifampicin-dependent/-enhanced multidrug-resistant tuberculosis.
Zhong, M.; Zhang, X.; Wang, Y.; Zhang, C.; Chen, G.; Hu, P.; Li, M.; Zhu, B.; Zhang, W.; Zhang, Y.
The International Journal of Tuberculosis and Lung Disease, Volume 14, Number 1, January 2010 , pp. 40-44(5)
Link to IJTLD abstract

Link to Science Daily article

severe fungal infections

2009-12-23T11:51:00.000-08:00

Syracuse University News Service (December 22, 2009

New Compounds May Control Deadly Fungal Infections

An estimated 25,000 Americans develop severe fungal infections each year, leading to 10,000 deaths despite the use of anti-fungal drugs. The associated cost to the U.S. health care system has been estimated at $1 billion a year.

Now two Syracuse University scientists have developed new brominated furanones that exhibit powerful anti-fungal properties.

The most virulent fungus is Candida albicans, which is carried by about 75 percent of the public. Typically the fungus is harmless but, in individuals with HIV or otherwise compromised immune systems, it can cause candidiasis, which has a high mortality rate. The fungi can also form biofilms that attach to surfaces and are up to 1,000 times more resistant to anti-fungals.

"These new furanones have the potential to control such infections and save lives," says assistant professor Dacheng Ren of the Department of Biomedical and Chemical Engineering in SU's L.C. Smith College of Engineering and Computer Science. "In our tests, they reduced fungal growth by more than 80 percent, and we hope to improve on that going forward."

Ren and his collaborator, chemistry professor Yan-Yeung Luk of SU's College of Arts and Sciences, have filed a non-provisional patent application. They have also published related results in the Journal of Applied Microbiology and Biotechnology.

Over the past 20 years, pathogenic fungi have developed growing resistance to anti-fungal drugs. This stimulated a strong demand for more effective drugs and led to the successful research at Syracuse. The researchers' genomic study suggests that furanones have different genetic targets than current anti-fungal agents and thus may avoid drug resistance acquired in the past. The research team has also shown previously that these furanones inhibit bacterial biofilm formation; thus they may help control chronic infections where biofilms often appear, on surgical, dental and other implants.

Ongoing furanones research at Syracuse University will investigate a broad spectrum of other potential capabilities, ranging from diverse medical uses, such as controlling bacterial and fungal biofilms, to anti-fungal wood preservatives for the building materials market

reference

Inhibition of Candida albicans growth by brominated furanones
Miao Duo, Mi Zhang, Yan-Yeung Luk and Dacheng Ren
Journal of Applied Microbiology and Biotechnology 10.1007/s00253-009-2174-6
Link to JAMB abstract

Link to SU news release

Bird Flu

2009-12-23T11:47:00.001-08:00

Science Daily (December 22, 2009)

Compound Found to Safely Counter Deadly Bird Flu

The specter of a drug-resistant form of the deadly H5N1 avian influenza is a nightmare to keep public health officials awake at night.

Now, however, a study published in the Proceedings of the National Academy of Sciences (PNAS) suggests that a new compound, one on the threshold of final testing in humans, may be more potent and safer for treating "bird flu" than the antiviral drug best known by the trade name Tamiflu.

Known as T-705, the compound even works several days after infection, according to Yoshihiro Kawaoka, a University of Wisconsin-Madison virologist and the senior author of the new study.

"H5N1 virus is so pathogenic even Tamiflu doesn't protect all the infected animals," explains Kawaoka, a professor of pathobiological sciences at the UW-Madison School of Veterinary Medicine and a world authority on influenza. "This compound works much better, even three days after infection."

The Wisconsin research was conducted in mice and demonstrated that the compound was effective and safe against H5N1 virus, the highly pathogenic bird flu virus, which some scientists fear could spark a global epidemic of deadly influenza. The compound is also effective against seasonal flu and more worrisome varieties such as the H1N1 virus, and has already been tested against circulating seasonal influenza in humans in Japan where it is on the brink of Phase III clinical trials in people.

The prospect of a new front-line drug for influenza, in particular highly pathogenic strains such as H5N1 virus, is important as there are few drugs capable of checking the shifty influenza virus. The new study showing the efficacy and safety of T-705 assumes more importance as instances of Tamiflu-resistant strains of H5N1 virus have recently been reported, raising concerns about the ability of current antiviral drugs to blunt a pandemic of deadly avian flu.

Antiviral drugs are viewed as a readily available first line of defense against pandemic flu and are especially important for protecting health workers and others during an outbreak of disease. Vaccines, which utilize inactivated or weakened viruses to confer immunity, are the primary line of defense for influenza, but require months to formulate and mass-produce.

Aside from its safety and basic efficacy, another key trait of the T-705 compound is the fact that it is effective even after an infection is acquired. Bird flu, notes Kawaoka, is almost always diagnosed in the hospital after symptoms of the disease manifest themselves: "This compound has a chance to save people who have gone into the disease course," he says.

T-705 targets a critical viral molecule, polymerase, an enzyme that enables the virus to copy its genetic material, RNA. By disabling polymerase, the virus is unable to make new virus particles and maintain the chain of infection. Tamiflu, which remains an effective drug for blocking influenza virus, targets and regulates the enzyme neuraminidase, a protein found on the surface of the flu virus particle and that is essential for spreading the virus throughout the respiratory system.

"The activity of this agent is considerably higher than Tamiflu," says Kawaoka, adding, "the compound is very specific to viral polymerase. It doesn't affect host polymerase, which is important for safety and reducing side effects."

reference

T-705 (favipiravir) activity against lethal H5N1 influenza A viruses
Maki Kiso, Kazumi Takahashi, Yuko Sakai-Tagawa, Kyoko Shinya, Saori Sakabe, Quynh Mai Le, Makoto Ozawa, Yousuke Furuta, and Yoshihiro Kawaoka
Proceedings of the National Academy of Sciences (PNAS) published online before print December 14, 2009, doi:10.1073/pnas.0909603107
Link to PNAS abstract

Link to Science Daily article

2009-12-23T00:22:00.000-08:00

John McCain 'Lost'

2009-12-22T19:21:00.001-08:00

It Doesn't Often Snow At Christmas

2009-12-22T19:16:00.001-08:00

Goin' To Town, CBS 1931

2009-12-22T19:14:00.001-08:00

Walk On The Wild Side

2009-12-22T19:09:00.001-08:00

2009-12-22T16:31:00.000-08:00

Martin Rowson - The Guardian

Link between concurrency and HIV?

2009-12-22T15:36:00.000-08:00

Roger Pebody for Aidsmap December 22, 2009

Concurrent sexual partnerships and the spread of HIV - ‘the evidence is limited’

The theory that multiple, overlapping sexual partnerships are a key driver of generalized HIV epidemics in Africa has been attacked as being based on insubstantial evidence. The critics, writing in the journals AIDS and Behavior and The Lancet, argue that researchers lack a precise definition of concurrency or a standard way to measure it, and that the data do not show a significant association between concurrency and either HIV incidence or prevalence.

However this critique has stimulated a fierce debate in the United States. Proponents of the concurrency thesis argue that the critics’ analysis of the data is selective, that evidence from a wide range of sources supports the thesis, and that it would be irresponsible for prevention programs in Africa to ignore this issue.

Concurrency

Concurrent sexual partnerships describe situations in which an individual has overlapping sexual relationships with more than one person. They can be contrasted with serial monogamy, when an individual has a sexual relationship with only one partner, with no overlap in time with subsequent partners.

A number of researchers, including Daniel Halperin, Timothy Mah and Martina Morris have suggested that concurrent relationships can increase the size of an HIV epidemic, the speed at which it infects a population and its persistence within a population.

The explanation for this is that in situations where a significant proportion of both men and women have concurrent relationships, even if they only have two partners each, as soon as one person in the network of concurrent relationship contracts HIV, then other people in the network are at risk (unless condoms are used). More people are more often exposed to the virus, including during the acute infection period when people are extremely infectious.

In contrast, in situations of serial monogamy, even if men and women have a relatively high number of sexual partners during their lifetime, one relationship is over before another is started. This means that if HIV is passed on within a relationship, it cannot be further transmitted as long as that relationship lasts.

Critique

Mark Lurie and Samantha Rosenthal argue that even if this theory is persuasive, empirical evidence for it is lacking. They call for better designed studies to clarify the contribution concurrency may make to generalized epidemics in Southern and Eastern Africa. Moreover, they believe that delivering prevention interventions around concurrency could be counter-productive and may divert resources away from other prevention methods that have proven efficacy.

Lurie and Rosenthal argue that concurrency is often vaguely and inconsistently defined. Some studies in fact collect data on total numbers of partners, and not concurrent relationships. Moreover, some include very brief or one-off liaisons (e.g. with a sex worker), but most do not.

Mah and Halperin, proponents of the concurrency thesis, accept that the lack of a consensus definition of concurrency or of a universally accepted method of measurement hampers comparison between studies.

They report a proposed standard definition from a UNAIDS working group: overlapping sexual partnerships where sexual intercourse with one partner occurs between two acts of intercourse with another partner.

The debate between Lurie and the other researchers focuses on the different type of research studies that may or may not demonstrate the contribution that concurrency makes.

The prevalence of concurrency in a population

A number of studies have taken a representative sample of a population to quantify the proportion of people who are participating in concurrent sexual relationships. These surveys show wide variation between different countries, with populations in sub-Saharan Africa tending to report much more concurrency than populations in other parts of the world.

Lurie and Rosenthal’s main criticism is that these studies simply cannot tell us anything about a link between concurrency and HIV.

In addition, they question the validity of comparisons between countries, given the variety of definitions used by researchers. They believe that there is no substantial evidence that levels of concurrency are significantly higher in Africa than elsewhere.

Lurie and the other authors tussle over the same studies. Referring to a review of sexual behavior in 59 countries, Lurie insists that it found that concurrency rates could not be compared and that African adults are less sexually active than adults in other regions. In contrast, Mah and Halperin provide the following quote from the same study: ‘‘Evidence is available that, although lifetime numbers of partners might be lower, concurrent relationships in men in some African countries might have been more common and of longer duration than in other regions’’.

Qualitative data

Whereas Mah and Halperin believe that qualitative research can demonstrate that concurrency is a highly normalized behavior in many parts of southern and eastern Africa and can help us understand its socio-cultural underpinnings, Lurie and Rosenthal dismiss qualitative research as inherently unrepresentative and prone to bias.

Individual studies

Only a few studies have compared individuals’ participation in concurrent relationships and their HIV status, and Lurie and Rosenthal note that a consistent relationship has not been found.

However Martina Morris, a leading researcher of concurrency, argues that such studies are “theoretically misguided and empirically irrelevant”. She says that concurrency is not a risk for the person who has more than one partner, but a risk for that person's partners. A monogamous partner may be exposed to HIV, not by his or her own behavior, but by the partner’s concurrency. Because of this, future studies will need to enroll partners.

Mah and Halperin also believe that concurrency increases an individual’s risk of transmitting HIV, not their risk of acquiring it. They point to studies from Uganda and Zimbabwe where HIV infection was associated with the belief that one’s partner was having concurrent relationships.

Population studies

In 2001, Lagarde and colleagues reported a study that used a standardized questionnaire to assess concurrency rates and HIV prevalence in five sub-Saharan cities. The study did not find that the two factors were correlated - for example, some lower prevalence cities had high rates of concurrency.

Lurie and Rosenthal cite this as a key study, but Martina Morris rejects the study design entirely. This is because HIV prevalence represents infections that have accumulated over many years, whereas the survey measured concurrency only in the previous year.

Mathematical modeling

Lurie and the proponents of concurrency all agree that the most powerful demonstrations of the influence of concurrency have come from simulation models. For example, Martina Morris and Mirjam Kretzschmar worked on Ugandan data and concluded that increasing the level of concurrency would have a more significant impact on epidemic spread than increasing the number of partnerships.

Lurie and Rosenthal say that even if these models show that concurrency can drive an epidemic, such theoretical work cannot demonstrate whether concurrency is actually doing so in Africa.

They also comment that other modeling studies, which found that the total number of partners or mixing between different social groups were more important than concurrency, tend not to be cited by the other authors.

In addition, in the articles published by Lurie and Helen Epstein, there is much claim and counter-claim as to the definitions used and the validity of the assumptions that were fed into the various modeling studies.

Conclusions

Mark Lurie and Samantha Rosenthal believe that the evidence base for the role of concurrency is weak and contradictory, and that better research with more refined definitions needs to take place before interventions to reduce concurrency can be delivered.

Morris counters that the studies Lurie and Rosenthal have looked at cannot prove or disprove the hypothesis. More sophisticated studies are being worked on and will give a more precise picture of concurrency’s role, “but no one argues that concurrency is irrelevant to transmission,” she says.

As such, she says it would be a “real tragedy” if methodological limitations were used to justify a do-nothing policy.

Mah and Halperin also argue that if HIV prevention interventions were never implemented until the most reliable evidence had been gathered, the only ones in use today would be male circumcision and interventions to prevent mother-to-child transmission. They believe that prevention messages which encourage people to have only one partner at a time are needed as one component of a prevention response.

References

Concurrent sexual partnerships and the HIV epidemics in Africa: evidence to move forward.
Timothy L. Mah & Daniel T. Halperin
AIDS and Behavior published online ahead of print,22 July, 2008 DOI 10.1007/s10461-008-9433-x.
Link to AIDS Behav abstract

Concurrent partnerships as a driver of the HIV epidemic in sub-Saharan Africa? The evidence is limited.
Mark N.Lurie & Samantha Rosenthal .
AIDS and Behavior published online ahead of print, 2 June, 2009. DOI 10.1007/s10461-009-9583-5
Link to AIDS Behav abstract

The evidence for the role of concurrent partnerships in Africa’s HIV epidemics: a response to Lurie and Rosenthal.
Timothy L. Mah & Daniel T. Halperin
AIDS and Behavior published online ahead of print, October 9, 2009 DOI 10.1007/s10461-009-9617-z
Link to AIDS Behav abstract.

The mathematics of concurrent partnerships and HIV: a commentary on Lurie and Rosenthal, 2009.
Helen Epstein
AIDS and Behavior published online ahead of print, 29 October, 2009 DOI 10.1007/s10461-009-9627-x.
Link to AIDS Behav abstract

Barking up the wrong evidence tree. Comment on Lurie & Rosenthal, “Concurrent Partnerships as a Driver of the HIV Epidemic in Sub-Saharan Africa? The Evidence is Limited”
Martina Morris
AIDS and Behavior published online ahead of print, 2009.
Link to AIDS Behav abstract

The concurrency hypothesis in sub-Saharan Africa: convincing empirical evidence Is still lacking. Response to Mah and Halperin, Epstein, and Morris.
Mark N. Lurie and Samantha Rosenthal
AIDS and Behavior published online ahead of print, 2009. DOI: 10.1007/s10461-009-9640-0
Link to AIDS Behav abstract

Concurrency driving the African HIV epidemics: where is the evidence?
Mark Lurie, Samantha Rosenthal, Brian Williams
The Lancet Volume 374: 1420 24 October, 2009 doi:10.1016/S0140-6736(09)61860-2
Link to The Lancet abstract

Concurrency driving the African HIV epidemics: where is the evidence? — Author's reply
James D. Shelton
The Lancet Volume 374: 1420 24 October, 2009 doi:10.1016/S0140-6736(09)61861-4
Link to The Lancet abstract

Link to Aidsmap article

‘Tanning as a fashion trend’

2009-12-22T15:35:00.000-08:00

Baylor University (December 21, 2009)

Adolescent Boys Seeking 'the Norm' May Take Risks With Their Appearances

— Teen-aged boys are more likely to use tanning booths, take diet pills and have their bodies waxed -- even if they think those activities are unhealthy -- if they are influenced by their peers, according to research by a Baylor University assistant professor of fashion merchandising.

Research also showed that boys ages 12 to 17 focused more on how their skin appears to others -- tone, texture and color -- than on other aspects of their appearance, including body shape, when they were influenced by peers, said Dr. Jay Yoo. His study has been awarded Best Paper in the psychological/social category by the International Textiles and Apparel Association.

The study will be published in fall 2010 in Adolescence, a quarterly international journal. Yoo studied 155 boys, with an average age of 14.3 years, in seven schools in the eastern United States.

"I studied what kids are teased about," Yoo said. "If anyone looks different, people tease you. Probably boys who have acne would become really self-conscious. There are cultural differences, but smooth skin is highly desired, and that may translate into other parts of the body.

"Skin tone also can represent the class of a person," Yoo said. "Skin that is dark brown or bronze is more ideal than pale. Tanning as a fashion trend is a relatively new phenomenon." While tanned skin once was associated with being blue collar, "a tan now is considered a sign of the leisure class," he said.

"As a result, the incident of skin cancers has risen dramatically over the past century."

Also, the availability of over-the-counter diet pills and media presentation of those products may make adolescents think taking them is the norm, Yoo said.

"They may view being slim as healthy, while being overweight is viewed as unhealthy. Taking diet pills is merely considered as a means to achieve slimness," he said.

He said the number of teen-age boys receiving spa services, such as hair removal, has nearly doubled since the early 1990s. Nearly half of the almost 14,000 spas in the United States compete for business by offering events and packages for teen-age boys, Yoo said.

"Boys used to use what was available in the bathroom cabinet," Yoo said. "But now it's aromatherapy and salon products, in which brand image as well as specific information are highlighted for adolescent consumers.

"I've heard a mother complaining about her son being teased in the locker room when he used to carry products that were not popular among his age group."

Peer influence is based on what adolescents observe as the norm, but also on advice or criticism from peers, Yoo said.

His findings about using a tanning booth, waxing skin and spa treatments suggest that appearance-conscious youths may share a wide range of information and experiences, he said.

"Until now, little research has been done about adolescents' appearance," Yoo said. But "adolescence is when they develop shopping patterns and appearance, and those who engage in risky behavior continue into adulthood."
Some of Yoo's findings about adolescent boy's perceptions of what is unhealthy behavior vs. their participation in those behaviors:

Activity: Perception as unhealthy-- Participation

Using diet pills: 75.2 percent -- 4 percent
Using tanning booths: 73.8 percent -- 9.4 percent
Getting a tattoo: 67.6 percent -- 10.1 percent
Body piercing: 66.7 percent --13.7 percent
Dyeing hair: 63.4 percent --11.6 percent
Sunbathing: 60.5 percent -- 27.7 percent
Waxing skin: 51.7 percent -- 6 percent

Link to Baylor news release

Hormone that suppresses reproduction

2009-12-22T15:28:00.000-08:00

Robert Sanders for U C Berkeley News (December 22, 2009)

New Human Reproductive Hormone Could Lead to Novel Contraceptives

Nearly 10 years after the discovery that birds make a hormone that suppresses reproduction, University of California, Berkeley, neuroscientists have established that humans make it too, opening the door to development of a new class of contraceptive and possible treatments for cancer or other diseases.

The hormone, gonadotropin inhibitory hormone (GnIH), has the opposite effect from gonadotropin releasing hormone, a key reproductive hormone. While GnRH triggers a cascade of hormones that prime the body for sex and procreation, GnIH puts a brake on the cascade.

"Identifying the inhibitory hormone in humans forces us to revise our understanding of the control mechanism of human reproduction," said first author Takayoshi Ubuka, a post-doctoral fellow in the UC Berkeley Department of Integrative Biology and in the Helen Wills Neuroscience Institute. "We hope this will stimulate clinical studies on people with precocious puberty or in the area of contraception."

Because reproductive hormones often promote the growth of cancer cells, GnIH might also work as an anti-cancer agent.

"Frequently, treatment of hormone-responsive cancers involves GnRH antagonists or very, very high doses of GnRH, which cause side effects," said George Bentley, UC Berkeley assistant professor of integrative biology. "Maybe we can use something that inhibits reproduction at physiological levels, so that we can bypass some of these side effects."

Ubuka, Bentley and their colleagues at UC Berkeley and in Japan and the United Kingdom report their findings in the Dec. 22 online issue of the public access journal PLoS ONE.

reference

Identification of Human GnIH Homologs, RFRP-1 and RFRP-3, and the Cognate Receptor, GPR147 in the Human Hypothalamic Pituitary Axis
Takayoshi Ubuka, Kevin Morgan, Adam J. Pawson, Tomohiro Osugi, Vishwajit S. Chowdhury, Hiroyuki Minakata, Kazuyoshi Tsutsui, Robert P. Millar, George E. Bentley
PLoS ONE 4(12): e8400. doi:10.1371/journal.pone.0008400
Link to PLoS ONE article

Link to UC Berkeley news release

no sex – no malaria

2009-12-22T15:26:00.000-08:00

BBC News on line (December 22, 2009)

Sex intervention combats malaria

It may be possible to combat malaria by interfering with the sex lives of the mosquitoes which spread the disease, according to scientists from The Imperial College London. They have shown that the insects can only mate successfully if the male is able to seal his sperm inside the female using a "mating plug". Without the plug, fertilization cannot occur, and they cannot reproduce.

The researchers focused on the species of mosquito primarily responsible for the transmission of malaria in Africa - Anopheles gambiae.

These insects mate only once in their lifetime, so disrupting the reproductive process offers a good way of dramatically reducing their numbers.

When they mate, the male transfers sperm to the female followed by a coagulated mass of proteins and seminal fluids known as a mating plug. This plug is not found in any other species of mosquito and its role had previously been unclear.

But the Imperial College team showed it was essential for ensuring sperm is correctly retained in the female's sperm storage organ, from where she can fertilize eggs over the course of her lifetime.

In the lab, the researchers were able to stop successful reproduction by preventing the formation of the plug in males.

Lead researcher Dr Flaminia Catteruccia said: "We have shown that the male mating plug is not a simple barrier to insemination from rival males, as has been previously suggested.
"Instead, we discovered that the plug plays an important role in allowing the female to successfully store sperm in the correct way inside her, and as such is vital for successful reproduction.
"Removing or interfering with the mating plug renders copulation ineffective. "This discovery could be used to develop new ways of controlling populations of A. gambiae mosquitoes, to limit the spread of malaria."

The researchers stopped the plug forming by knocking out a key enzyme which causes the seminal fluids to coagulate into a gelatinous solid mass.

Dr Catteruccia said: "If in the future we can develop an inhibitor that prevents the coagulating enzyme doing its job inside male A. gambiae mosquitoes in such a way that can be deployed easily in the field - for example in the form of a spray as it is done with insecticides - then we could effectively induce sterility in female mosquitoes in the wild.

"This could provide a new way of limiting the population of this species of mosquito, and could be one more weapon in the arsenal against malaria."

reference

Transglutaminase-mediated Semen Coagulation Controls Sperm Storage in the Malaria Mosquito
David W. Rogers, Francesco Baldini, Francesca Battaglia, Maria Panico, Anne Dell, Howard R. Morris, and Flaminia Catteruccia.
PLoS Biology, 7(12): e1000272. doi:10.1371/journal.pbio.1000272
Link to PLoS Biology article

Primer:Finding the Right Plugin: Mosquitoes Have the Answer.
Tracey Chapman
PLoS Biology, 7(12): e1000273. doi:10.1371/journal.pbio.1000273
Link to PLoS Biology primer

Link to BBC news report

Joy To The World

2009-12-21T19:12:00.001-08:00

Spitting Image

2009-12-21T19:10:00.001-08:00

Dirty words

2009-12-21T19:08:00.001-08:00

Three Minute Philosophy: Rene Descartes

2009-12-21T18:57:00.001-08:00

Hot spot

2009-12-21T16:34:00.000-08:00

Researchers Attack British Medical Journal

2009-12-21T15:18:00.001-08:00

Science Daily (December 21, 2009)

Conflict Over War Deaths: Researchers Attack British Medical Journal Review Process

Researchers from Canada, the UK and Sweden have slammed the influential British Medical Journal (BMJ) for publishing an error-filled study on global war deaths, refusing an equivalent rebuttal article and having a flawed peer-review process.

"This is not some trivial academic disagreement," says Andrew Mack, director of the Simon Fraser University-based Human Security Report Project (HSRP), which published a detailed critique of the BMJ's claims in the December issue of the Journal of Conflict Resolution (JCR).

"Accurate statistics on the health impacts of war are critically important not just for researchers but also for humanitarian organizations whose assistance programs save millions of lives around the world."

The HSRP article, "Estimating War Deaths: An Arena of Contestation," takes issue with a 2008 BMJ piece by Harvard researcher Ziad Obermeyer and colleagues, which rejected widely accepted battle-death statistics compiled by the International Peace Research Institute, Oslo (PRIO).

The PRIO data reveal that global war deaths declined by more than 90 per cent between 1946 and 2002.

But the BMJ claimed in a release publicizing the Obermeyer article that "war has killed three times more people than previously estimated and there is no evidence to support claims of a recent decline in war deaths."

Mack and HSRP study co-author Michael Spagat at the University of London, both leading experts on the subject, determined that the BMJ article failed to substantiate either assertion, was marred by serious mistakes and showed little understanding of the research it critiqued.

So Mack, the former strategic planning director to UN Secretary-General Kofi Annan, emailed the BMJ identifying six major methodological and factual errors in the Obermeyer article "Fifty Years of Violent War Deaths from Vietnam to Bosnia."

"The problems we point out would have been obvious to any of the many conflict researchers familiar with the research being criticized," says Spagat.

The U.K. journal acknowledged none of the errors, he says, and it ruled out publishing a detailed rebuttal, claiming the Obermeyer study was very thoroughly reviewed by appropriate experts.

"But the BMJ is well aware that its peer review process is flawed," says Spagat. "A recent study, whose authors include the journal's current editor, revealed that, on average, only a third of the 'major errors' deliberately inserted in a BMJ article were picked up by reviewers."

Adds Mack: "There appears to be no way of effectively rebutting BMJ articles that contain unwarranted -- and damaging -- critiques of the work of other scholars.

"This makes the journal effectively unaccountable by shielding it from serious criticism."

The JCR paper and technical appendix, PRIO battle deaths data, the BMJ paperBMJ peer review are all available on line and technical appendix, and a paper on the
Link to HSRP

References:

Estimating War Deaths: An Arena of Contestation.
Michael Spagat, Andrew Mack, Tara Cooper, Joakim Kreutz
Journal of Conflict Resolution, 2009; 53 (6): 934 DOI: 10.1177/0022002709346253
Link to JCR abstract

Fifty years of violent war deaths from Vietnam to Bosnia: analysis of data from the world health survey programme.
Ziad Obermeyer, Christopher J L Murray, Emmanuela Gakidou.
British Medical Journal, 2008; 336: 1482-1486 DOI: 10.1136/bmj.a137
Link to BMJ abstract

Link to Science Daily article

Bedside manner

2009-12-21T15:15:00.000-08:00

Loyola University Health System news release (December 18, 2009)

Doctors' Bedside Skills Trump Medical Technology

Sometimes, a simple bedside exam performed by a skilled physician is superior to a high-tech CT scan, a Loyola University Health System study has found.

Researchers found that physicians' bedside exams did a better job than CT scans in predicting which patients would need to return to the operating room to treat complications such as bleeding.

"The low cost, simple, but elegant neurological exam appears to be superior to a routine CT scan in determining return to the operating room," researchers report in the Journal of Neurosurgery.

Patients typically receive CT scans following open brain surgery to remove tumors, repair aneurysms, treat brain injuries, etc. But practices vary. Some surgeons order CT scans right after surgery. Others wait until the following morning.

There are downsides. CT scans cost hundreds of dollars and expose patients to radiation. Transporting patients to scanning machines "involves multiple personnel of varying skills and nursing staff who are taken away from their other unit responsibilities," researchers wrote. "These scans also often interfere with work flow efficiencies of the radiology department."

The lead author of the study is Dr. Ahmad Khaldi, chief resident in the Department of Neurological Surgery at Loyola University Chicago Stritch School of Medicine. The senior author is Dr. Thomas Origitano, chairman of the Department of Neurological Surgery.

Researchers examined the records of 251 patients who received CT scans within 24 hours of surgery at Loyola. They included 133 patients who received routine scans within seven hours of surgery and 108 patients who received routine scans between 8 hours and 24 hours after surgery. None of the routine scans predicted which patients would need to return to the operating room.

Patients also received bedside neurological exams by physicians. In 10 cases, physicians detected serious problems, such as being slow to wake up, that warranted an urgent CT scan. Three of these urgent scans (30 percent) confirmed the patients' problems were serious enough to require a return to the operating room. By comparison, 0 percent of the 241 routine CT scans predicted whether patients would have to return to the emergency room.

A normal CT scan given right after surgery might give a doctor a false sense of security, which could lead to less frequent monitoring and neurological exams. Of the 14 patients in the study who took a serious turn for the worse, 13 had had CT scans within four hours of surgery that were normal or showed only minor problems.

"Scanning technology is really good," Origitano said. "But applying it without a physician's input is not necessarily helpful."

reference

The clinical significance and optimal timing of postoperative computed tomography following cranial surgery
Ahmad Khaldi, M.D., Vikram C. Prabhu, M.D., Douglas E. Anderson, M.D., and Thomas C. Origitano, M.D., Ph.D.
Journal of Neurosurgery 1-5.Posted online on 18 Dec 2009.
Link to JNS contents

Link to Loyola Medicine news release

Attorney density = MRSA?

2009-12-21T15:11:00.001-08:00

Science Daily (December 20, 2009)

Fear of Lawsuits May Prompt Some Doctors to Overprescribe Antibiotics

A new study led by a team of researchers at New York Medical College suggests that that medical liability concerns may be playing a role in the increase of MRSA in healthcare settings by encouraging clinicians to prescribe antibiotics more often and more broadly than clinical circumstances and evidence-based guidelines warrant.

The study appeared in the September-October issue of the American Journal of Therapeutics.

The team analyzed census figures, statistics on population density of attorneys and physicians, and data on antibiotic utilization for the United States, Canada, and 15 European countries. They compared this to statistics on the percentage of methicillin resistance among clinical isolates of S. aureus. They found a strong correlation between the prevalence of methicillin resistance and density of attorneys in countries in Europe and North America. They found no correlation between prevalence of methicillin resistance and physician density.

Investigators surveyed 162 healthcare providers to determine whether medical liability concerns were as important as antibiotic cost and formulary restrictions in selecting treatment regimens. The surveys also confirmed that physicians were more concerned about medical liability in cases of under-prescribing antibiotics rather than by over-prescribing them.

George Sakoulas, M.D., assistant professor of medicine and lead author of the study, concluded, "The findings suggest that more research is needed to evaluate the potential impact of medical liability concerns on the medical care system. The study findings hint toward the importance of medical tort reform as a way to reduce healthcare costs and improve quality. Another way might be to foster more judicious prescription of antibiotics based on science and evidence rather than on risk aversion."

Reference:

Relationship Between Population Density of Attorneys and Prevalence of Methicillin-Resistant Staphylococcus aureus: Is Medical-Legal Pressure on Physicians a Driving Force Behind the Development of Antibiotic Resistance?
Sakoulas, George; Wormser, Gary P; Visintainer, Paul; Aronow, Wilbert S; Nadelman, Robert B.
American Journal of Therapeutics, 2009; September/October 2009 - Volume 16 - Issue 5 - pp e1-e6 DOI: 10.1097/MJT.0b013e3181727946
Linl to AJT abstract

Link to Science Daily article

Hydra helps?

2009-12-21T15:07:00.000-08:00

Science Daily (December 20, 2009)

Antimicrobial Peptide from Ancient Organism May Be Effective Against Multiresistant Human Pathogens Including MRSA

Researchers in Germany have identified a new antimicrobial peptide that demonstrates significant activity against a variety of bacteria, including multiresistant human strains such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). The discovery was made while investigating the ancient metazoan organism Hydra magnipapillata.

The researchers from Christian-Albrechts-University and the University Medical Center Schleswig-Holstein Campus, Kiel, Germany report their findings in the December 2009 issue of the journal Antimicrobial Agents and Chemotherapy.

While occurrences of multidrug-resistant infections continue to increase, the discovery and development of drugs effective against these bacterial strains have slowed. Once commonly thought of as a hospital-acquired infection, MRSA has now spread to the community (now known as community acquired or CA-MRSA) and is infecting previously healthy young people who have not been recently hospitalized or undergone a medical procedure. Past research has proven that ancient organisms are well equipped at preventing infectious pathogens from entering the body and given the desperate need for new drug targets, further exploration of these organisms is warranted.

MRSA has already developed resistance to CA-MRSA human antimicrobial peptides and prior studies have shown antibacterial immune responses in the simple metazoan Hydra magnipapillata to include bactericidal peptides with novel structural features and modes of action. In the study researchers identified the antimicrobial peptide arminin 1a from Hydra and found that it exhibited significant and wide-spread activity against bacteria including MRSA and enterococci, a common cause of nosocomial infections that is also drug-resistant. Further observations revealed that bacteria are killed when the bacterial cell wall is disrupted and the antibacterial activity of arminin 1a isn't affected by exposure to salt in human blood. Finally, researchers determined that arminin 1a doesn't share any ancestry with any known antimicrobial peptides.

"Our data suggest that ancient metazoan organisms such as Hydra hold promise for the detection of novel antimicrobial molecules and the treatment of infections caused by the multiresistant bacteria," say the researchers.

Reference:

Activity of the Novel Peptide Arminin against Multiresistant Human Pathogens Shows the Considerable Potential of Phylogenetically Ancient Organisms as Drug Sources.
René Augustin, Friederike Anton-Erxleben, Stephanie Jungnickel, Georg Hemmrich, Björn Spudy, Rainer Podschun, and Thomas C. G. Bosch.
Antimicrobial Agents and Chemotherapy, 2009; 53 (12): 5245 DOI: 10.1128/AAC.00826-09
Link to AAC abstract

Link to Science Daily article