EPA Makes Decision To Designate Areas Not Meeting Standards For Fine Particle Pollution, USA
EPA has notified 25 governors and 23 tribal leaders that certain areas in their states and tribal lands do not meet the agency’s daily standards for fine particle pollution, also known as PM 2.5.
“These designations are an important step in our steady march toward cleaner air,” said EPA Administrator Stephen L. Johnson. “We will continue working with our state and tribal partners to meet these air quality standards.”
EPA closely reviewed recommendations from states and tribes along with public comments before making its decision to designate 211 counties and parts of counties as not meeting EPA’s PM 2.5 standards. These areas, called nonattainment areas, include counties with monitors violating the standards and nearby areas that contribute to that violation. Affected states and tribes will be required to take steps to reduce the pollution that forms fine particles. The vast majority of U.S. counties and tribal lands are meeting these standards, but will need to continue working to maintain clean air.
In 2006, EPA strengthened the 24-hour fine particle standards from 65 micrograms per cubic meter to 35 micrograms per cubic meter of air to protect public health. Nationwide, monitored levels of fine particle pollution fell 11 percent from 2000 to 2007. Fine particles can either be emitted directly, or they can form in the atmosphere from reactions of sulfur dioxide and nitrogen oxides. Exposure to fine particle pollution can cause a number of serious health problems including aggravated asthma, increased hospital admissions and emergency room visits for respiratory and cardiovascular disease, heart attacks and premature death.
– More information on the designations
EPA (Environmental Protection Agency)
Vitamin Supplements Do Not Reduce Cancer Risk, More Evidence
US researchers studying the effect of beta carotene, vitamin C and vitamin E, either singly or in combination, on over 7,000 women found the
supplements did not reduce their risk of getting cancer compared to women who did not take the supplements. However an expert who reviewed the
study said that while the overall message was there was no link, it uncovered some interesting evidence that should not be overlooked.
The randomized, double-blind, placebo-controlled study was the work of researchers from Brigham and Women’s Hospital and Harvard Medical
School, Boston, Massachusetts and is published in the 30 December Advance Access online issue of the Journal of the National Cancer
Institute.
A number of observational studies have suggested it is likely that diets high in fruit and vegetables, both rich sources of vitamins (also called
antioxidants), prevent cancer. But randomized trials have mostly failed to establish a significant link between the use of antioxidants and cancer risk,
wrote the authors in their background material.
For this study, the researchers examined data on 7,627 women who were cancer-free at the start of the study. They were part of a cohort of over 8,000
taking part in the Women’s Antioxidant Cardiovascular Study where all participants had been randomly assigned to take either vitamin C (500 mg of
ascorbic acid daily), natural source vitamin E (600 IU of {alpha}-tocopherol every other day), beta-carotene (50 mg every other day), all three
supplements, or placebo.
They consulted hospital reports and the National Death Index to get details of cancer diagnoses (including specific site of tumor), and deaths, and
analysed the results using advanced statistical tools to assess the relative risks of common cancers associated with the use of the supplements, either
individually or in combination. They also tried to establish if cancer risk was affected by how long the supplements were taken for.
The results showed that:
- Over an average 9.4 years of treatment, 624 women developed incident invasive cancer and 176 women died from cancer.
- There were no statistically significant links between antioxidant use and total cancer incidence.
- The relative risks (RR) compared to placebo were: vitamin C group RR was 1.11 (95% confidence interval [CI] = 0.95 to 1.30); vitamin E group
RR was 0.93 (95% CI = 0.79 to 1.09); beta carotene group RR was 1.00 (95% CI = 0.85 to 1.17).
- There were also no significant links between antioxidant use and cancer mortality.
- Again, compared to placebo, the RRs were for vitamin C 1.28 (95% CI = 0.95 to 1.73), for vitamin E 0.87 (95% CI = 0.65 to 1.17) and for beta
carotene 0.84 (95% CI = 0.62 to 1.13).
- None of the antioxidants showed a significant link with cancer incidence and death with longer use.
- Combined use of the three antioxidants also had no significant effect on these two outcomes.
Note that a relative risk of 1.00 compared to placebo means the risk is the same, so 0.95 is slightly lower and 1.05 is slightly higher.
Confidence Intervals (CI) are a statistician’s way of showing how much confidence one should have in the calculated relative risk, in the sense that a 95%
CI of 0.65 to 1.17 means that if you were to run the same “experiment” 100 times, there is a 95 per cent chance that you would get a result in this
range.
The researchers concluded that:
“Supplementation with vitamin C, vitamin E, or beta carotene offers no overall benefits in the primary prevention of total cancer incidence or cancer
mortality.”
They wrote that the trial showed:
“Neither duration of treatment nor combination of the three antioxidant supplements had effects on overall fatal or nonfatal cancer events.”
“Thus, our results are in agreement with a recent review of randomized trials indicating that total mortality was not affected by duration of
supplementation and single or combined antioxidant regimens,” added the researchers.
An accompanying editorial by Dr Demetrius Albanes of the National Cancer Institute, reviewed data from previous randomized controlled trials that
examined supplement use and cancer incidence.
Albanes wrote that while this particular study reports there is no link between supplement use and lowering of cancer risk, the results contain valuable
information. For example, there was a trend for reduced colon cancer incidence with use of vitamin E, which confirms findings in other
studies.
Also, this study linked beta carotene use to a “modest excess” of lung cancer, which is also consistent with other reports, wrote Albanes, who
concluded that:
“Null trials or those with unexpected outcomes should not, however, be viewed as failures; they have and will continue to shed light on the causes of
cancer and help us discover the means for its prevention.”
“Vitamins C and E and Beta Carotene Supplementation and Cancer Risk: A Randomized Controlled Trial.”
Jennifer Lin , Nancy R. Cook , Christine Albert , Elaine Zaharris , J. Michael Gaziano , Martin Van Denburgh , Julie E. Buring , and JoAnn E.
Manson.
Journal of the National Cancer Institute Advance Access published on December 30, 2008.
DOI 10.1093/jnci/djn438.
Click here for Abstract.
Sources: Journal abstract, Journal of the National Cancer Institute.
Written by: Catharine Paddock, PhD
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today
Motor Nerve Targeting To Limb Muscles Is Controlled By Ephrin Proteins
A study from a team of researchers including Dr. Artur Kania, Director of the Neural Circuit Development Research Unit at the IRCM, and Dr. Dayana Krawchuk, postdoctoral fellow, shows how a family of proteins present in the developing limb control nerve targeting from the spinal cord to the muscles of the limb. This discovery, co-authored by scientists from Columbia University in New York City, is published on December 26, 2008 in the journal Neuron.
The nervous system is a highly precise and intricate nerve network whose major purpose is to analyze and respond to external stimuli through coordinated movement. Such precision stems from the accuracy of nerve connections formed between neurons and muscles. “To understand how this occurs,” explains Dr. Kania, “we study a simple system in which nerves extend from the spinal cord to the limb to connect to either flexor muscles (i.e. biceps arm muscle) or extensor muscles (i.e. triceps arm muscle).”
Previously, the researchers found that nerves connecting to extensor muscles were guided towards specific targets by a protein present in the developing limb (ephrin-A). Using chick and mouse embryos as models, the team of scientists now discovered that nerves connecting to the antagonist muscle group, the flexor muscles, are guided by a closely-related protein family, also present in the developing limb (ephrin-B). Together, these studies present a complete picture of how both limb nerves correctly connect the nervous system to muscles. Furthermore, by studying the wiring of a relatively simple nerve connection, the team of scientists has discovered a molecular strategy that is very likely widely used in the nervous system to wire much more complex neural circuits, such as those required for learning, memory and coordinated movement.
Miswiring of the nervous system is thought to be a factor in disorders such as epilepsy and mental retardation. By studying the process of limb nerve development, this team of scientists contributes further to the development of new strategies for treatment of patients with a diseased and damaged nervous system. That is because knowing how nerves form is crucial in designing therapies that aim to rebuild damaged or diseased nerves.
“The study of the ephrin proteins should help us understand diseases such as autism, schizophrenia as well as a number of neurological disorders,” says Dr. Rémi Quirion, a scientific director at the Canadian Institutes of Health Research (CIHR). “We are proud to support this important study and hope it will help to improve the lives of people with these health problems.”
The experiments in Artur Kania’s laboratory were funded by the EJLB Foundation, the Canadian Institutes of Health Research (CIHR) including the Institute of Genetics, as well as the Canada Foundation for Innovation (CFI), and the IRCM.
Reference: Luria V, Krawchuk D, Jessell TM, Laufer E, and Kania A. (2008) Specification of Motor Axon Trajectory by Ephrin-B:EphB Signaling: Symmetrical Control of Axonal Patterning in the Developing Limb. Neuron, December 26; 60(6): 1039-1053.
The on-line version of this article is available at: www.cell.com/neuron/current.
Dr. Artur Kania is Director of the Neural Circuit Development Research Unit at the IRCM. He is Associate Researcher in the Department of Medicine at the Université de Montréal and is also Associate Member in the Division of Experimental Medicine and Adjunct Professor in the Department of Anatomy and Cell Biology at McGill University.
Established in 1967, the Institut de Recherches Cliniques de Montreal (IRCM)
now has 37 research units specialized in areas as diverse as systems biology, immunity and viral infections, cardiovascular and metabolic diseases, cancer, medicinal chemistry, clinical research and ethics. It has a staff of more than 450 people. The IRCM is an independent institution, affiliated with the Université de Montréal and has built, over the years, a close collaboration with McGill University.
Source
Dr. Artur Kania
Director of the Neural Circuit
Development Research Unit
Institut de recherches cliniques de Montreal
http://www.ircm.qc.ca
and
Lucette Thériault
Communications Director
Institut de recherches cliniques de Montreal
http://www.ircm.qc.ca
Sleep Disorder May Be Early Sign Of Dementia Or Parkinson’s Disease
People with a sleep disorder that causes them to kick or cry out during their sleep may be at greater risk of developing dementia or Parkinson’s disease, according to a study published in the December 24, 2008, online issue of Neurology®, the medical journal of the American Academy of Neurology.
The sleep disorder is called REM sleep behavior disorder. People with the disorder do not have the normal lack of muscle tone that occurs during REM sleep, often known as the dream stage of sleep. Instead, they have excessive muscle activity such as punching, kicking, or crying out, essentially acting out their dreams.
The study involved 93 people with this type of sleep disorder who had no signs of a neurodegenerative disease, such as dementia or Parkinson’s disease. The participants were followed for an average of five years. During that time, 26 of the people developed a neurodegenerative disease. Fourteen developed Parkinson’s disease, 11 developed dementia and were diagnosed with either Alzheimer’s disease or Lewy body dementia. One person developed multiple system atrophy, a rare disorder that affects movement, blood pressure and other body functions.
The estimated five-year risk of developing a neurodegenerative disease was 18 percent, with the 10-year risk at 41 percent and the 12-year risk at 52 percent.
“These results are obviously of great interest to people who have this sleep disorder and their physicians and families,” said study author Ronald B. Postuma, MD of McGill University in Montreal, Canada, who carried out the studies at the sleep disorders center at the Sacre Coeur hospital, University of Montreal. Postuma is also a member of the American Academy of Neurology. “The results may help us better understand how these neurodegenerative diseases develop. They also suggest that there may be an opportunity for protecting against the progression to disease, perhaps even preventing it before the symptoms can appear.”
Postuma noted that the study involved only people with no known cause for the REM sleep behavior disorder. The disorder can also be caused by narcolepsy or rare brainstem abnormalities. REM sleep disorder from these causes does not necessarily carry the risk of developing a neurodegenerative disease, he said.
The study was supported by grants from the Canadian Institutes of Health Research and the FRSQ (Fonds de la recherché en santé du Quebec) in Montreal, Canada.
The American Academy of Neurology, an association of more than 21,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as Parkinson’s disease, ALS (Lou Gehrig’s disease), dementia, West Nile virus, and ataxia. For more information about the American Academy of Neurology, visit http://www.aan.com.
Better Antifreezes To Preserve Donor Organs For Transplantation – Journal Of The American Chemical Society
Chemists in Canada have developed a new approach for producing more effective medical antifreeze fluids for preserving kidneys, hearts, and other organs donated for transplantation. These next-generation antifreezes can decrease damage to organs caused by ice crystals, and thus prolong the time a donated organ will remain viable prior to transplantation. This could increase the number of available organs for potential recipients. Their study is scheduled for the current issue of the Journal of the American Chemical Society, a weekly publication.
Robert N. Ben and colleagues note that the growth of ice crystals is a major cause of damage to cells, tissues and organs during cryopreservation, which leaves them unusable for transplantation. To address this challenge, the researchers developed synthetic antifreeze materials, called C-linked antifreeze glycoprotein analogues (C-AFGP). These proteins contain a sugar coating and have custom-tailored antifreeze activity.
Now the scientists describe the development of “hydration index” that can be used to more reliably predict how prospective antifreeze materials will behave. Their index provides a clearer picture of how water molecules interact with the sugar component (as well as native AFGP) and affect their chemical behavior. This is a key to understanding their ability to resist the formation of ice crystals when chilled.
“Hydration Index – A Better Parameter for Explaining Small Molecule Hydration in Inhibition of Ice Recrystallization”
Click here to view article online
American Chemical Society (ACS)
The American Chemical Society is a congressionally chartered independent membership organization which represents professionals at all degree levels and in all fields of chemistry and sciences that involve chemistry.
http://www.acs.org
Producing A More Effective Oral Form Of A Powerful Disease-fighting Protein – Bioconjugate Chemistry Journal
Scientists in Japan are reporting an advance toward using a natural disease-fighting protein in pills or syrups that patients can take by mouth rather than injection. Their study is the first to show that coating the protein with a polymer material already in wide medical use can increase its absorption by the intestine. The research appears in the current issue of ACS’ Bioconjugate Chemistry, a monthly journal.
In the study, Atsushi Sato and colleagues note that the protein – lactoferrin (LF) – occurs in saliva, breast milk and other body fluids, where it has powerful effects in fighting bacteria, viruses, and inflammation. LF is sparking excitement as a potential treatment for cancer, gangrene, hepatitis, and a host of other diseases. Although LF is available as a dietary supplement and as an experimental oral drug, acid in the stomach quickly destroys existing forms of LF, reducing the protein’s effects.
The scientists found that laboratory rats absorbed 10 times more LF if the protein is coated with the polymer, called polyethylene glycol (PEG). In addition, the coated PEG remained active in the bloodstream longer than the uncoated protein. The scientists also showed that the coated drug retained most of its disease-fighting potency, including antibacterial, antioxidative and anti-inflammatory activity, compared to the uncoated drug. The PEG-coating technique not only is a promising advance toward making lactoferrin an oral drug, but also may be used to convert other healthful food proteins into useful drugs, the researchers note. – MTS
ARTICLE
“Development of Poly(ethylene glycol) Conjugated Lactoferrin for Oral Administration”
Click here to view article online
American Chemical Society (ACS)
The American Chemical Society is a congressionally chartered independent membership organization which represents professionals at all degree levels and in all fields of chemistry and sciences that involve chemistry.
http://www.acs.org
Child’s ADHD Diagnosis Is Tied To Mother’s Health Status
The probability of having one’s child receive an attention deficit hyperactivity disorder (ADHD) diagnosis involves a mother’s own medical conditions and her use of health services prior to having the child, a new study finds.
What is not clear, however, is whether the effects are due to biological, environmental or psychosocial factors – or some combination of these.
The new study implies “that the diagnoses and health care utilization that a mother receives prior to having her child is predictive of having a child who is diagnosed with ADHD,” said G. Thomas Ray, lead author. “Our study raises the possibility that certain types of mothers – those who get or seek diagnoses and who use more health services – may be more likely to seek ADHD diagnoses for their children.”
Ray works in the research division at Kaiser Permanente in Northern California. The study appears in the January issue of the journal Medical Care.
Specifically, Ray said, “The mothers of children who are diagnosed with ADHD are more likely to be diagnosed with health conditions such as depression and anxiety disorder and use more health services in the year prior to, and the two years after, the birth of their child, than mothers of children without ADHD or the mothers of children with asthma.”
Using records from a Northern California Kaiser Permanente database, the researchers identified three groups: mothers of children with ADHD, mother of children without ADHD and mothers of children with asthma. Authors then compared the mothers’ diagnoses, health care use and costs among the groups.
Mothers of children with ADHD spent about $1,000 more on health care in the year before and in the two years following the birth of their child compared to mothers who did not have children with ADHD and they had more illnesses than mothers of children with asthma did.
Sam Goldstein, Ph.D., editor of the Journal of Attention Disorders and a research professor of psychology at George Mason University, said the new study expands on previous work.
For example, a 1985 study from the American Journal of Orthopsychiatry “identified poor maternal health during pregnancy, young age of mothers, previous miscarriage, first pregnancy, prematurity, long labor and toxemia as maternal factors that significantly differentiated children with ADHD from controls,” Goldstein said.
“Keep in mind that the diagnosis of ADHD for the time being is not medical but behavioral,” Goldstein said. “A host of phenomena can contribute to the adverse behavioral symptoms that lead to a diagnosis of ADHD.”
Ray recommends that future studies address the methods making an ADHD diagnosis, since such diagnoses are relatively subjective and since parents, teachers and physicians all influence the process.
Ray GT, Croen LA, Habel LA.
“Mothers of children diagnosed with attention-deficit/hyperactivity disorder: health conditions and medical care utilization in periods before and after birth of the child.”
Medical Care, 47(1), 2009.
Health Behavior News Service
http://www.hbns.org
Health Plan Restraints May Keep Patients From Choosing Quality Care
Public reports on the quality of care delivered by health plans might motivate patients to choose better providers – if they are not constrained by issues of cost and accessibility to doctors, according to a review of recent studies.
The findings, published in the January 2009 issue of Medical Care, shed some light on the puzzle of why people repeatedly say they are interested in quality when it comes to health care, but rarely make it a priority when they choose their providers.
In real-life situations, when individuals were choosing a new health care plan, fewer than 5 percent said that quality information had influenced their choice of health care provider, said lead author Marjan Faber, Ph.D. She was with the Centre for Quality of Care Research when the study was conducted.
Faber and colleagues analyzed 14 studies, all conducted in the United States.
Cost and physician choice “clearly influence the weight given to quality information within a health plan setting,” Faber said.
In particular, features such as premiums, out-of-pocket costs, the ability to keep one’s own doctor and customer service all compete with quality information when it comes to choosing a provider, according to the researchers.
In most of the studies, quality data came from the Consumer Assessment of Health care Providers and Systems (CAHPS) program, a public-private initiative led by the U.S. Agency for Healthcare Quality and Research that collects information from a variety of surveys of patient care.
Ten studies asked patients about quality data in a hypothetical, laboratory setting; while the other four studies focused on how new Medicaid patients used the CAHPS information to choose a health plan in real-world situations.
Patients seem to be more sensitive to quality of care information if they are dissatisfied with their current provider, newly diagnosed with a specific condition, or choosing a new health insurance plan, the researchers found.
However, most people do not have a lot of time to research new plans, and “many consumers in the U.S. are increasingly constrained by reductions in health plan options and the benefits covered,” said Faber, who is now with the Scientific Institute for Quality of Healthcare.
Across all studies, the researchers found that the presentation of the quality data – and its readability – made a significant difference in whether people used or ignored the data.
Judith Hibbard, Dr.P.H., an expert in public reporting of health data at the University of Oregon, said that many patients have a difficult time wading through the unfamiliar numbers and less user-friendly formats of some quality reports. “Until we make these compelling to consumers, we’re not going to have the improvements in quality,” she said.
Faber M. et al.
“Public reporting in health care: how do consumers use quality-of-care information? A systematic review.”
Medical Care, 47(1), 2009.
Health Behavior News Service
http://www.hbns.org
Sierra Leone AIDS Director Praises AHF For “One Million Tests/World AIDS Day 2008″ Campaign
AIDS Healthcare Foundation (AHF) is proud to announce that it has received a “Letter of Appreciation” from the government of Sierra Leone expressing gratitude for AHF’s partnership in the recent “One Million Tests/World AIDS Day 2008″ campaign. The worldwide campaign spearheaded by AHF, brought together 1000 global partners in 72 countries, including non-governmental organizations (NGOs), local and national governments, international relief agencies, faith-based organizations and civil society in a collaborative effort to conduct free HIV tests to one million people around the global in observance of World AIDS Day 2008.
Having made a commitment to provide 20,000 free HIV tests to its citizenry as part of the campaign, Sierra Leone’s National HIV/AIDS Council and Secretariat exceeded that goal by conducting 23,063 HIV tests in twelve districts in the week leading up to World AIDS Day, November 26th to December 1st 2008. In a remarkable collaboration between the government, non-profit and private sectors, these tests were conducted in part due to a successful partnership with Inverness Medical Innovations, Inc. who generously donated 10,000 “Determine” HIV tests, half of the total provided to the government of Sierra Leone. Funding for the additional 10,000 tests was provided by AHF.
In the letter, Dr. Brima Kargbo, MD, MPH, Director of the National HIV/AIDS Council and Secretariat, states: “I am pleased to inform you that Sierra Leone tested 23,063 people (9,424 males and 13,639 females). We are very much appreciative of the test kits that were made available for the exercise. We hope our collaboration will continue to be strengthened.”
“We humbly and gratefully receive this acknowledgement from the government of Sierra Leone and would like to return the compliment by praising the remarkable commitment of the National HIV/AIDS Council and Secretariat. We would also like to express our thanks to Inverness for its generous donation of 10,000 HIV tests to the Sierra Leone World AIDS Day effort,” said Terri Ford, Director of Global Advocacy for AIDS Healthcare Foundation. “To make this happen, AHF, the Sierra Leone government and Inverness united in a powerful trio of NGO, government and industry. This is a great example of how, with a united effort, great strides can be made in the fight against AIDS.”
Add Ms. Ford: “We are also pleased to announce that as a result of this successful partnership, AHF has been invited to meet with the Sierra Leone government in Freetown to discuss further collaboration for expanded testing and treatment services in the country.”
Full text of the letter below:
National HIV/AIDS Secretariat
15A Kingharman Road
Brookfields,
Freetown
Sierra Leone
Re: NHAS/WAD/2008
16th December 2008
Terri M. Ford
Director, Global Advocacy
Director, One Million Tests Campaign
AIDS Healthcare Foundation
Dear Terri,
LETTER OF APPRECIATION
On behalf of the National HIV/AIDS Council and its Secretariat I wish to express our profound thanks and appreciation to you and your institution in particular for the recent support in commemorating World AIDS Day 2008 in Sierra Leone. Your support was very timely and clearly manifested the commitment of your institution in partnering with us in the global campaign against the spread of the HIV.
I am pleased to inform you that Sierra Leone tested 23,063 people (9,424 males and 13,639 females). We are very much appreciative of the test kits that were made available for the exercise. We hope our collaboration will continue to be strengthened.
Once more, I register my thanks and appreciation on behalf of the People Living with HIV/AIDS (PLHIV) to you and your entire team. We look forward to a continued close collaboration as we are on the verge of stabilizing the epidemic in Sierra Leone.
Yours Sincerely,
Dr. Brima Kargbo, MD, MPH, Certified
Director, National HIV/AIDS Secretariat
About AHF
AIDS Healthcare Foundation (AHF) is the largest non-profit HIV/AIDS organization in the US. AHF currently provides medical care and/or services to more than 93,000 individuals in 21 countries worldwide in the US, Africa, Latin America/Caribbean and Asia. Additional information is available at http://www.aidshealth.org.
Blood Sugar Linked To Decline Of Memory And Cognitive Health In Older People
US researchers examining how diseases in late life, such as stroke and diabetes, contribute to cognitive decline through their effect on the
hippocampal region of the brain found that high blood sugar may contribute to the decline of memory and cognitive health in older people. They suggested exercising to improve blood sugar levels was a way some people might be able to delay the normal decline in memory and cognitive
health that occurs in old age.
The study was the work of researchers at the Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University College of
Physicians and Surgeons in the City of New York, and colleagues from other research centres in the US, and was published online in the 23 December
issue of the Annals of Neurology.
Scientists already knew that the early stages of Alzheimer’s disease damage the hippocampus, an area of the brain essential for memory and learning,
and some studies have also suggested that this part of the brain is also vulnerable to normal aging. However, until this study, evidence as to the
underlying causes has remained somewhat elusive.
Using magnetic resonance imaging (MRI) the researchers mapped the hippocampal region of the brains of 240 people whose average age was 80
years. None of the participants had symptoms of dementia or Alzheimer’s and they all underwent a comprehensive medical exam.
60 of the participants had type 2 diabetes, and MRI scans showed 74 of them had brain infarcts (a type of brain tissue damage that results from
strokes). Using the MRI maps, the researchers then tried to identify which of the hippocampal subregions were affected by these two types of late-life
disease (diabetes and strokes).
Then, using these results, they looked at functional MRI (fMRI) studies in diabetic mice and aging rhesus monkeys to see whether these confirmed
their proposed classifications.
The results showed that:
- Although both diabetes and brain infarcts were linked to hippocampal dysfunction, they were associated with different regions of the
hippocampus, suggesting these late life diseases operated through different mechanisms.
- The hippocampal subregion linked to diabetes suggested blood glucose was the underlying mechanism, and this was confirmed with the fMRI
imaging in the aging rhesus monkeys and diabetic mice.
- The hippocampal subregion linked to brain infarcts suggested transient hypoperfusion (temporary loss of blood supply) was the underlying
mechanism, and this was provisionally confirmed by comparing affected blood vessel patterns in participants with infarcts in different places.
The researchers concluded that:
“Taken together with previous findings, these results clarify how diseases of late life differentially target the hippocampal formation, identify
elevations in blood glucose as a contributing cause of age-related memory decline, and suggest specific interventions that can preserve cognitive
health.”
The area of the hippocampus that was linked to blood sugar was the dentate gyrus, which the researchers had already established as a main contributor
of normal age-related memory decline in an earlier study.
The researchers also looked at other measures, like body mass index, cholesterol and insulin levels, to see if they correlated with decreasing activity in
this hippocampal region but they only found a strong link with blood sugar levels.
In a separate press release, lead investigator Dr Scott A. Small, associate professor of neurology in the Sergievsky Center and in the Taub Institute at
Columbia University Medical Center said that:
“Showing for the first time that blood glucose selectively targets the dentate gyrus is not only our most conclusive finding, but it is the most important
for ‘normal’ aging: that is hippocampal dysfunction that occurs in the absence of any disease states.”
“There have been many proposed reasons for age-related hippocampal decline; this new study suggests that we may now know one of them,” he
added.
“This is news even for people without diabetes since blood glucose levels tend to rise as we grow older,” said Small.
Small suggested that exercising to improve blood sugar levels could be a way for some people to delay the normal decline in memory and cognitive
health that occurs in old age.
“Whether through physical exercise, diet or drugs, our research suggests that improving glucose metabolism could help some of us avert the cognitive
slide that occurs in many of us as we age,” he added.
“This research used imaging in both human volunteers and in animal models to help us better understand the basic mechanisms behind hippocampal
dysfunction in the aged,” said Dr. Marcelle Morrison-Bogorad, director of the Division of Neuroscience at the National Institute on Aging (NIA), one
of the sponsors of the study.
“While more research is needed into the complex interaction of late-life disease and how it may affect the hippocampus, this new study is part of an
ongoing effort to identify specific areas where interventions might preserve cognitive health,” he added.
“The brain in the age of old: The hippocampal formation is targeted differentially by diseases of late life.”
William Wu, Adam M. Brickman, Jose Luchsinger, Peter Ferrazzano, Paola Pichiule, Mitsuhiro Yoshita, Truman Brown, Charles DeCarli, Carol A.
Barnes, Richard Mayeux, Susan J. Vannucci, Scott A. Small
Annals of Neurology Volume 64, Issue 6, Published Online 23 Dec 2008, Pages: 698-706
DOI: 10.1002/ana.21557
Click here for
Abstract.
Sources: Journal abstract, Columbia University Medical Center.
Written by: Catharine Paddock, PhD
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today
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