duminică, 5 august 2012
marți, 13 decembrie 2011
Risk Of Death And Stroke In Those With Heart Disease Increased By Herbal Amphetamine
Also Included In: Stroke; Heart Disease
Article Date: 13 Dec 2011 - 2:00 PST
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Chewing the natural stimulant khat increases the risk of death and stroke in patients with heart disease compared to those who are not users, according to new research in Circulation: Journal of the American Heart Association.
Since ancient times, people in the Arabian Peninsula and East Africa have chewed the fresh leaves of the Catha edulis plant which has effects similar to amphetamines and cocaine. It causes euphoria, hyperactivity, restlessness, loss of appetite and weight loss.
In Yemen, some people have khat picnics, chewing the leaves for as much as three hours, like tobacco chewing. Its use has spread globally throughout Western Europe and into the United States. Seven metric tons of khat travel through Heathrow Airport in England each week, and fresh and dried khat has been seized and confiscated in the United States where it is illegal, researchers said.
In the 2nd Gulf Registry of Acute Coronary Events (Gulf RACE-2) Study, researchers - comparing 1,408 khat chewers to 5,991 people who didn't use khat - found: In the hospital, khat users had a 7.5 percent death rate from heart disease compared to 3.8 percent in those who were not khat users. At one month, the death rate was 15.5 percent among khat users and 6.4 percent for non-khat users. At one year, the death rate was 18.8 percent among khat users compared to 10.8 percent among non-users. For the study, researchers enrolled men and women from 65 hospitals in Saudi Arabia, Bahrain, Yemen, Qatar, United Arab Emirates and Oman.
About 96 percent of the khat users were from Yemen, where khat is legal and socially acceptable, unlike the other countries in the study.
"Global awareness of the negative impact of khat chewing on health and social life is warranted before it becomes endemic," said Jassim Al Suwaidi, M.B., Ch.B., study co-author and Consultant Cardiologist and Director of Cardiovascular Research in the Department of Cardiology and Cardiovascular Surgery at Hamad General Hospital in Doha, Qatar. "This report underscores the importance of improving education about the cardiovascular risks of khat chewing as well as the need for further studies in the field."
Furthermore, researchers found: Khat chewers were more likely to be men (only 14 percent were women) and had lower cardiovascular risk factors such as diabetes mellitus, hypertension and dyslipidemia. Death rates were consistently higher among khat users up to age 80, but khat chewing occurs across the spectrum of young and old, male and female. Users were more likely to experience adverse health effects, including heart failure, recurrent ischemia, a second heart attack, cardiogenic shock and stroke compared to non-users. Women were as likely as men to experience adverse heart effects. Male khat chewers were more likely to develop stroke, particularly hemorrhagic (bleeding) stroke, compared to non-users. The increased risk of stroke wasn't significant among women using khat. The worse in-hospital outcomes may be related to delays in people getting to the hospital after the onset of symptoms and failing to receive thrombolytic (clot-busting) therapy or treatment with beta blockers, researchers said. Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
Visit our alcohol / addiction / illegal drugs section for the latest news on this subject. Co-authors are: Waleed M. Ali, M.D.; Al Habib KF, M.D.; Ahmed Al Motarreb, M.D.; Rajvir Singh, Ph.D.; Ahmad Hersi, M.D.; Hassam Al Faleh, M.D.; Nidal Asaad, M.M.B.S.; Shukri Al SaiF, M.D.; Wael Almameed, M.D.; Kadhim Sulaiman, M.D.; Haitham Amin, M.D.; Jawad Al-Lawati, M.D.; Nizar Al Bustani, M.D.; Norah Q. Al-Sagheer, M.D.; and Awad Al-Qahtani, M.B.Ch.B.
Author disclosures and sources of funding are on the manuscript.
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13 Dec. 2011.
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luni, 12 decembrie 2011
People With DFNA2 Hearing Loss Show Increased Touch Sensitivity
Article Date: 12 Dec 2011 - 1:00 PST
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People with a certain form of inherited hearing loss have increased sensitivity to low frequency vibration, according to a study by Professor Thomas Jentsch of the Leibniz-Institut für Molekulare Pharmakologie (FMP)/Max Delbrück Center for Molecular Medicine (MDC) Berlin-Buch and Professor Gary Lewin (MDC), conducted in cooperation with clinicians from Madrid, Spain and Nijmegen, the Netherlands. The research findings, which were published in Nature Neuroscience *, reveal previously unknown relationships between hearing loss and touch sensitivity: In order to be able to 'feel', specialized cells in the skin must be tuned like instruments in an orchestra.
The members of the Spanish and Dutch families who participated in the study were quite amazed when the researchers from Berlin unpacked their testing equipment. Many of the family members suffer from hereditary DFNA2 hearing loss, but the researchers were less interested in their hearing ability than in their sense of touch. The hearing impairment is caused by a mutation which disrupts the function of many hair cells in the inner ear. This mutation, the researchers suspected, might also affect the sense of touch.
Tiny, delicate hairs in our inner ear vibrate to the pressure of the sound waves. The vibrations cause an influx of positively charged potassium ions into the hair cells. This electric current produces a nerve signal that is transmitted to the brain - we hear. The potassium ions flow through a channel in the cell membrane and again out of the hair cells. This potassium channel, a protein molecule called KCNQ4, is destroyed by the mutation in hearing-impaired people. The sensory cells gradually die off due to overload. "But we have found that KCNQ4 is present not only in the ear, but also in some sensory cells of the skin," Thomas Jentsch explained. "This gave us the idea that the mutation might also affect the sense of touch. And this is exactly what we were able to show in our research, which we conducted in a close collaboration with the lab of Gary Lewin, a colleague from the MDC who is specialized in touch sensation."
Whether we caress our child, search in our bag for a certain object or hold a pen in our hand - each touch conveys a variety of precise and important information about our environment. We distinguish between a rough and smooth surface by the vibrations that occur in the skin when the surface is stroked. For the different touch stimuli there are sensory cells in the skin with different structures - through the deformation of the delicate structures, electric nerve signals are generated. Exactly how this happens is still a mystery - of the five senses of Aristoteles, the sense of touch is the least understood.
Clearly there are parallels to hearing, as the findings of Matthias Heidenreich and Stefan Lechner from the research groups of Thomas Jentsch and Gary Lewin show. As a first step, the researchers in the Jentsch lab created a mouse model for deafness by generating a mouse line that carries the same mutation in the potassium channel as a patient with this form of genetic hearing loss. The touch receptors in the skin where the KCNQ4 potassium channel is found did not die off due to the defective channel like they did in the ear, but instead showed an altered electric response to the mechanical stimuli in the mutated mouse. They reacted much more sensitively to vibration stimuli in the low frequency range. The outlet valve for potassium ions normally functions here as a filter to dampen the excitability of the cells preferentially at low frequencies. This normally tunes these mechanoreceptors to moderately high frequencies in normal people. In mice lacking functional KCNQ4 channels, these receptors can no longer distinguish between low and high frequencies.
The deaf patients with mutations in the potassium channel who were examined by Stefan Lechner and Matthias Heidenreich showed exactly the same effect. They could even perceive very slow vibrations that their healthy siblings could not perceive. Due to mutations in the KCNQ4 channel gene, the fine tuning of the mechanoreceptors for normal touch sensation was altered.
The sensation of touch varies greatly from person to person - some people are much more sensitive to touch than others. DFNA2 patients are extremely sensitive to vibrations, according to Gary Lewin and Thomas Jentsch. "The skin has several different types of mechanoreceptors, which respond to different qualities of stimuli, especially to different frequency ranges. The interaction of different receptor classes is important for the touch sensation. Although the receptors we studied became more sensitive due to the loss of the potassium channel, this may be outweighed by the disadvantage of the wrong 'tuning to other frequencies'. With KCNQ4 we have for the first time identified a human gene that changes the traits of the touch sensation."
Article adapted by Medical News Today from original press release. Click 'references' tab above for source.Visit our hearing / deafness section for the latest news on this subject. The research group led by Thomas Jentsch belongs both to the FMP and the MDC in Berlin and studies ion transport and its role in disease. The group led by Gary Lewin belongs to the MDC and is specialized in peripheral sensory perception.
*KCNQ4 K+ channels tune mechanoreceptors for normal touch sensation in mouse and man. http://dx.doi.org/10.1038/nn.2985
Matthias Heidenreich1,2,9, Stefan G Lechner2,9, Vitya Vardanyan1,2,8, Christiane Wetzel2, Cor W Cremers3, Els M De Leenheer4, Gracia Aránguez5, Miguel Ángel Moreno-Pelayo6, Thomas J Jentsch1,2,7 & Gary R Lewin2,7
1Leibniz-Institut für Molekulare Pharmakologie (FMP), Berlin, Germany. 2Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany. 3Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. 4Department of Otorhinolaryngology, Head and Neck Surgery, Ghent University Hospital & Ghent University, Ghent, Belgium. 5Servicio de Otorrinolaringología, Hospital General Universitario Gregorio Marañón, Madrid, Spain. 6Unidad de Genética Molecular, Hospital Ramón y Cajal, IRYCIS, CIBERER, Madrid, Spain. 7Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Berlin, Germany. 8Present address: Institute of Molecular Biology, Yerevan, Armenia. 9These authors contributed equally to this work.
Helmholtz Association of German Research Centres Please use one of the following formats to cite this article in your essay, paper or report:
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12 Dec. 2011.
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duminică, 11 decembrie 2011
Diagnosis Of Tuberculosis Is Increased In Postpartum Women
Also Included In: Women's Health / Gynecology
Article Date: 10 Dec 2011 - 1:00 PST
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The incidence of tuberculosis (TB) diagnosis is significantly increased in mothers postpartum, suggesting a potential new population to target for screening, according to a new UK-wide cohort study.
In the joint study between the Health Protection Agency and the University of East Anglia, researchers analyzed data on all women with pregnancies between 1996 and 2008 from the General Practice Research Database, which contains records from 460 practices across the UK, representing 5.5 percent of the UK population. The findings were published online ahead of print publication in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.
"Ours is the first primary care based cohort study to quantify the risk of TB during pregnancy and postpartum," said Dominik Zenner, degree? consultant in public health, Respiratory Diseases Department at the Health Protection Agency. "Although we found a significantly increased risk of TB in the six months following pregnancy, but not during pregnancy, the risk during pregnancy is almost certainly also increased."
The researchers estimated incidence rates for TB in pregnancy, six months postpartum and outside of pregnancy, and modelled adjusted incidence rate ratios (IRRs) in a retrospective cohort study. They also performed a nested self-controlled case series (SCCS) analysis, adjusting for all non-time-dependent confounders, such as country of origin and ethnicity. In the SCSS analysis, pregnant women with TB were selected from the cohort, and incidence rates (IRs) in pregnancy and post-partum were compared with rates outside pregnancy.
A total of 192,801 women with a total of 264,136 pregnancies were included in the cohort study. Of 177 TB events that occurred during the study, 22 occurred during pregnancy and 22 occurred in the 180 days after pregnancy. The crude TB rate for the combined pregnancy and post-partum period was 15.4 per100,000 person years, which was significantly higher than the rate outside of pregnancy (9.1 per 100,000 person years, p=0.02). After adjustment for age, region and socio-economic status, post-partum TB risk was significantly higher than TB risk outside pregnancy (IRR 1.95, CI 1.24-3.07), whereas no significant increase during pregnancy was observed (IRR 1.29, CI 0.82-2.03).
These observations were confirmed in the SCCS analysis. Adjusting for all non-time bound confounders, the time period of observation and patients' age, the IRR of TB during pregnancy (1.03, CI 0.64-1.65) was not significantly increased compared with the risk outside of pregnancy. However, the TB risk was significantly increased in the 6 month period following pregnancy (IRR 1.61, CI 1.01-2.58, p=0.04).
The study had a few limitations, including its observational design. Administrative delay between TB diagnosis and recording of the diagnosis may have occurred. Diagnostic delays may also occur during pregnancy. Immunological changes during pregnancy gradually increase TB susceptibility and then gradually normalize after delivery. The combination of these factors may account for the failure to show a significantly increased TB risk during pregnancy in this study.
"The incidence of TB diagnosis is significantly increased post-partum, probably reflecting an increase in TB incidence during pregnancy," concluded Dr. Zenner. "Given our results, targeted screening of pregnant and post-partum women in high-risk groups may be warranted, given that delays in treatment initiation are associated with poorer outcomes for both mothers and their children."
Article adapted by Medical News Today from original press release. Source: American Thoracic SocietyVisit our tuberculosis section for the latest news on this subject. Please use one of the following formats to cite this article in your essay, paper or report:
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10 Dec. 2011.
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