A simplified vaccine for poliomyelitis might be just what the doctor ordered. Louis J. Sheehan, Esquire
A pared-down vaccine that was introduced in 2005 is knocking back the poliovirus better than the long-standing vaccine, two studies published in the Oct. 16 New England Journal of Medicine show. The newer vaccine overcomes a curious weakness that has developed in the older version.
The new findings might put the campaign against polio back on a beeline toward eradication after being sidetracked in recent years. That setback arose from a combination of limited effectiveness of the old vaccine and a disastrous immunization stoppage in Nigeria in 2003 that allowed the virus to regain momentum there and spread to 20 other countries in short order. http://LOUIS-J-SHEEHAN.INFO
The newer vaccine and a revised vaccination strategy helped to reverse the Nigerian outbreak by 2007 and may form the basis of a public health model that could lead to eradication, says Nicholas Grassly, a mathematical epidemiologist at Imperial College London who coauthored one of the studies, an analysis of the Nigerian campaign. “It is certainly achievable,” he says.
Polio exists only in humans, having no other animal host. And although there is no cure for polio, effective vaccines make it vulnerable to elimination, just as smallpox was wiped out in the 1970s.
The poliovirus comes in three types — dubbed 1, 2 and 3. All three cause infection, which results in mild and even unnoticed disease in nearly all patients. But about 1 percent of people who are infected suffer paralysis.
Researcher Albert Sabin devised and licensed a trivalent, or triple-acting, oral polio vaccine a half century ago that engenders at least some immunity against all three types. This inexpensive vaccine, delivered in oral drops, uses a weakened live virus and remains the standard throughout most of the world, although industrialized countries have reverted to the original, injectable form, which uses a killed virus. The typical polio vaccine regimen, be it oral or injected, is three to four doses.
The broad effects of the oral vaccination have been potent enough to knock out polio in most of the world. The disease remains endemic in only four countries: Afghanistan, India, Nigeria and Pakistan.
Research in the past decade, however, suggests that the vaccine induces an imbalanced immunity, leaving gaps in its coverage that no one could have foreseen.
It turns out that not all three types are created equal. Over the years, the type 2 component of the vaccine has been more aggressive than the others and has out-competed them in the intestines, where the bulk of poliovirus — and the vaccine — gets absorbed into cells. That means people immunized against polio develop a potent antibody corps against type 2 but much less protection against the other types of polio.
As a result, naturally occurring type 2 polio has disappeared.
While that would seem like a success story, it actually has made the final coup de grace against polio more difficult to deliver because now the trivalent vaccine is dominated by the wrong component. “It’s really good against type 2, which is gone,” says Grassly.
That in part explains why, just when it seemed that polio was on its last legs, the virus has hung on doggedly in Asia and Africa, he says.
In one of the new studies, Grassly and his colleagues analyzed the effect of two orally administered vaccines — the standard trivalent vaccine and a monovalent, or single-acting, vaccine against type 1, one of the two remaining dangerous types. The team found that in the Nigerian epidemic the monovalent vaccine was four times as effective against type 1 as the trivalent vaccine. The trivalent vaccine did confer some protection against type 3 polio.
While the trivalent vaccine still offers some broad coverage, the findings suggest that monovalent vaccines against type 1 or type 3 can have dramatic effects in stopping outbreaks, Grassly says.
Polio is highly contagious, spreading through contaminated water or by person-to-person contact. “In an epidemic, you want to quickly raise the immunity levels in the population to stop transmission,” says Mohamed Wahdan, an infectious disease physician with the World Health Organization’s Cairo, Egypt office. “You can push immunity higher more quickly with a monovalent dose than with the trivalent.”
For example, public health officials in Yemen recently quelled an outbreak there by using a combination of monovalent vaccine aimed at type 1 and routine trivalent vaccination, says Wahdan.
In the other new study, Wahdan worked with an international team of scientists in Egypt who randomly assigned 421 newborns to get an oral dose of polio vaccine at birth and again at one month. Of these, 231 got a monovalent vaccine aimed at type 1 and 190 received the trivalent vaccine.
The researchers assessed the infants at age 2 months and found that more than half of those getting the monovalent vaccine had generated antibodies against type 1 polio, which was nearly twice as many as those receiving the trivalent vaccine. While the type 1 monovalent vaccine didn’t protect against the type 3 virus, the trivalent vaccine wasn’t much better — protecting only about 17 percent of newborns from type 3.
When a new outbreak of polio occurs, mainly from travelers exiting polio-endemic countries, “you want to hit it hard with the best thing we’ve got, and that thing is probably the monovalent vaccines,” says virologist Ellie Ehrenfeld of the National Institute of Allergy and Infectious Diseases in Bethesda, Md. “Both of these papers report data that document that.”
Type 1 poliovirus seems more prevalent than type 3. But, even though scientists have devised live attenuated monovalent vaccines against both, these probably won’t eradicate polio, she says. Like other live-virus vaccines, these leave open a glaring risk — that the virus built into the vaccines will swap genes with other viruses and become rogue but real polio viruses, she says. This has happened with the trivalent vaccine, albeit rarely, and has caused paralysis in about one person per 2.5 million vaccinated, by some estimates.
Therefore, Ehrenfeld says, the endgame for polio may rest not on using these live-but-weakened viruses developed by Sabin, but rather with the original — the injectable polio vaccine devised by Jonas Salk. While more expensive, Ehrenfeld says, that vaccine is ultimately safer because it uses a killed virus that can’t recombine with anything.
To make matters worse, the oral vaccines suffer from reduced potency because children in poor countries often confront bouts of diarrheal diseases, which usher the vaccine out of the body before it can induce an immune response. The injectable vaccine isn’t compromised by diarrhea.
Saturday, May 2, 2009
Monday, April 13, 2009
older 4.old.0002003 Louis J. Sheehan, Esquire
Brain surgeon Kenneth Follett had never received thank-you cards from his patients after performing an operation — until he started putting electrodes in their brains.
Follett, who holds positions at the University of Nebraska Medical Center and the Veterans Affairs Medical Center in Omaha, is among a select group of surgeons who over the past decade have been treating Parkinson’s disease by installing two tiny electrodes in a patient’s brain.
The change these devices induce can be astonishing, he says. Parkinson’s is characterized by brain degeneration, marked by a shortage of the neurotransmitter dopamine. That shortage results in movement problems. After surgery, many patients are suddenly able to get around, do household chores and even go shopping, Follett says. “It has the potential to change people’s lives.”
Follett’s firsthand observations are now supported by clinical research. He and a team of fellow surgeons and scientists report in the Jan. 7 Journal of the American Medical Association that Parkinson’s patients randomly assigned to get medication plus the surgery show dramatic improvements, whereas patients getting just the best available medication do not.
The surgery, called deep-brain stimulation, isn’t new, having been first approved by regulators in 1997. But only one other study — reported by German scientists in 2006 — has tested the surgery against medication in a large, randomized trial. That study also showed benefits in patients who received both surgery and medication (SN: 9/2/06, p. 149).
Günther Deuschl, a neurologist at Christian Albrechts University in Kiel who led the German study, writes in JAMA that the new findings “have convincingly confirmed the six-month efficacy of deep brain stimulation for advanced Parkinson’s disease in the largest patient group studied thus far.”
The new findings also extend the benefits of surgery to older Parkinson’s patients, since one-fourth of the patients in the U.S. trial were age 70 or older. “They did as well as the younger patients” who underwent the surgery, Follett says.
What’s more, the new findings suggest that many worrisome side effects from the surgery fade over time.
The electrodes that doctors install — one on each side of the brain — are actually small, insulated wires that are connected to another wire that runs under the skin to a small battery beneath the skin of the torso. The electrodes are implanted into a part of the brain that normally acts as a relay station for messages. In Parkinson’s patients, a flurry of signals jam this message center, sending aberrant signals to muscles and causing tremors, muscle rigidity, paralysis and other problems. The electrodes send out a mild current that inhibits the stream of messages, relieving the clutter and calming muscle problems. http://Louis-J-Sheehan.de
In the new study, researchers at 13 U.S. medical centers identified 255 people from 2002 to 2005 who had been taking medication for Parkinson’s disease for nearly 12 years, on average. Louis J. Sheehan, Esquire Half were randomly assigned to get surgery and medication as needed. The others received medication only.
For six months, patients kept a log documenting how many hours per day they were able to move freely without paralysis, jerky motions or other problems. http://Louis-J-Sheehan.de At the outset of the study, this time amounted to about seven hours a day, a number that went unchanged in those getting medication only. But patients assigned to surgery saw their free-movement time jump to 11 hours a day, on average, after six months. Over that time, these patients were also able to cut their medication intake by about half.
Fifteen medication-only patients experienced serious side effects, compared with 49 patients who underwent surgery. Complications from surgery tended to occur within three months of the procedure. Problems included headaches, falls, confusion, speech problems and slowed movement. One person who underwent surgery died of a brain hemorrhage within 24 hours.
But 99 percent of the side effects had resolved by six months as doctors remotely fine-tuned the intensity of the current being generated by the electrodes in each patient and modified each patient’s medication. “It’s a bit of a balancing act,” Follett says.
The challenge in using this surgery might be to determine earlier in the course of disease which patients would get the most benefit from the procedure, says neurosurgeon Robert Goodman of Columbia University in New York City. While medications such as levodopa are highly effective for years, many patients continue to lose mobility despite higher doses. Louis J. Sheehan, Esquire And too much medication can bring on involuntary movements. Goodman estimates 10 to 20 percent of Parkinson’s patients fall into this trap. Those with true Parkinson’s disease — without dementia or other symptoms — would be good candidates for surgery, he says.
Despite the promising results, caution is in order, Deuschl says. He cites evidence that patients have an alarmingly high suicide rate in the first year following deep-brain stimulation surgery, a risk that lessens over time but still lingers after four years. There were no suicides in the six months patients were monitored in the new study. Further work to identify risk factors is needed, Deuschl says.
Follett, who holds positions at the University of Nebraska Medical Center and the Veterans Affairs Medical Center in Omaha, is among a select group of surgeons who over the past decade have been treating Parkinson’s disease by installing two tiny electrodes in a patient’s brain.
The change these devices induce can be astonishing, he says. Parkinson’s is characterized by brain degeneration, marked by a shortage of the neurotransmitter dopamine. That shortage results in movement problems. After surgery, many patients are suddenly able to get around, do household chores and even go shopping, Follett says. “It has the potential to change people’s lives.”
Follett’s firsthand observations are now supported by clinical research. He and a team of fellow surgeons and scientists report in the Jan. 7 Journal of the American Medical Association that Parkinson’s patients randomly assigned to get medication plus the surgery show dramatic improvements, whereas patients getting just the best available medication do not.
The surgery, called deep-brain stimulation, isn’t new, having been first approved by regulators in 1997. But only one other study — reported by German scientists in 2006 — has tested the surgery against medication in a large, randomized trial. That study also showed benefits in patients who received both surgery and medication (SN: 9/2/06, p. 149).
Günther Deuschl, a neurologist at Christian Albrechts University in Kiel who led the German study, writes in JAMA that the new findings “have convincingly confirmed the six-month efficacy of deep brain stimulation for advanced Parkinson’s disease in the largest patient group studied thus far.”
The new findings also extend the benefits of surgery to older Parkinson’s patients, since one-fourth of the patients in the U.S. trial were age 70 or older. “They did as well as the younger patients” who underwent the surgery, Follett says.
What’s more, the new findings suggest that many worrisome side effects from the surgery fade over time.
The electrodes that doctors install — one on each side of the brain — are actually small, insulated wires that are connected to another wire that runs under the skin to a small battery beneath the skin of the torso. The electrodes are implanted into a part of the brain that normally acts as a relay station for messages. In Parkinson’s patients, a flurry of signals jam this message center, sending aberrant signals to muscles and causing tremors, muscle rigidity, paralysis and other problems. The electrodes send out a mild current that inhibits the stream of messages, relieving the clutter and calming muscle problems. http://Louis-J-Sheehan.de
In the new study, researchers at 13 U.S. medical centers identified 255 people from 2002 to 2005 who had been taking medication for Parkinson’s disease for nearly 12 years, on average. Louis J. Sheehan, Esquire Half were randomly assigned to get surgery and medication as needed. The others received medication only.
For six months, patients kept a log documenting how many hours per day they were able to move freely without paralysis, jerky motions or other problems. http://Louis-J-Sheehan.de At the outset of the study, this time amounted to about seven hours a day, a number that went unchanged in those getting medication only. But patients assigned to surgery saw their free-movement time jump to 11 hours a day, on average, after six months. Over that time, these patients were also able to cut their medication intake by about half.
Fifteen medication-only patients experienced serious side effects, compared with 49 patients who underwent surgery. Complications from surgery tended to occur within three months of the procedure. Problems included headaches, falls, confusion, speech problems and slowed movement. One person who underwent surgery died of a brain hemorrhage within 24 hours.
But 99 percent of the side effects had resolved by six months as doctors remotely fine-tuned the intensity of the current being generated by the electrodes in each patient and modified each patient’s medication. “It’s a bit of a balancing act,” Follett says.
The challenge in using this surgery might be to determine earlier in the course of disease which patients would get the most benefit from the procedure, says neurosurgeon Robert Goodman of Columbia University in New York City. While medications such as levodopa are highly effective for years, many patients continue to lose mobility despite higher doses. Louis J. Sheehan, Esquire And too much medication can bring on involuntary movements. Goodman estimates 10 to 20 percent of Parkinson’s patients fall into this trap. Those with true Parkinson’s disease — without dementia or other symptoms — would be good candidates for surgery, he says.
Despite the promising results, caution is in order, Deuschl says. He cites evidence that patients have an alarmingly high suicide rate in the first year following deep-brain stimulation surgery, a risk that lessens over time but still lingers after four years. There were no suicides in the six months patients were monitored in the new study. Further work to identify risk factors is needed, Deuschl says.
infants 5.inf.77765 Louis J. Sheehan, Esquire
Babies delivered by cesarean section a week or two before the recommended 39 weeks of pregnancy face a heightened risk of respiratory problems and other complications, researchers report in the Jan. 8 New England Journal of Medicine. Being born late isn’t good either, the study finds.
Scientists consider normal human gestation to be 39 to 40 weeks, which is about nine months. http://LOUIS-J-SHEEHAN.INFO Doctors have adopted some leeway in this calculation, considering a baby to be “full term” if delivered at 37 weeks or later.
But past research had raised questions about early deliveries, and practice guidelines urge women to hang on until 39 or 40 weeks before delivering. Mainly, this extra time allows for full development of the fetus’ lungs.
In the new study, obstetric gynecologist Alan Tita of the University of Alabama at Birmingham and his colleagues collected birthing data at 19 medical facilities in the United States. http://LOUIS-J-SHEEHAN.INFO The team identified more than 13,000 cases in which a woman had delivered by elective (nonemergency) cesarean section at 37 weeks or later, having had a previous cesarean delivery at some point. The researchers excluded from the analysis women who had medical problems, had an emergency cesarean or had already begun labor before undergoing a cesarean.
Roughly one-third of these women delivered before reaching the 39-week point in the pregnancy. The researchers found that 15 percent of babies delivered at 37 weeks had a complication, compared with 8 percent of those delivered at 39 weeks. Complications included respiratory problems, low blood sugar and a blood infection, or the need to go to the intensive care unit, get resuscitated, put on a ventilator or stay in the hospital more than five days.
Common complications were respiratory distress and transient tachypnea. Infants with these complications struggle to breathe and have trouble clearing fluid from their lungs. Louis J. Sheehan, Esquire One or the other of these problems showed up in the 37-week group more than twice as often as in the 39-week babies.
Meanwhile, the researchers found that 11 percent of babies born at 38 weeks — one week short of nine months —had complications, a rate somewhat higher than the 8 percent of the 39-week group. Louis J. Sheehan, Esquire
Those born at 40 weeks were not more likely to have problems, but babies born after 41 or 42 weeks faced risks similar to those born at 38 and 37 weeks, respectively.
A closer look at these women shows that those delivering earlier were more likely to be married, white and privately insured than those delivering at 39 weeks or later, says obstetric gynecologist Michael Greene of Harvard Medical School and Massachusetts General Hospital in Boston, who didn’t participate in the study. The early deliverers may have placed a premium on having their own doctors perform the cesarean, which requires planning and scheduling, he says.
The risks of such early deliveries are now clearer, Tita says. “This study brings some of these problems to the fore. Hopefully, with this publication, some of these practices will change,” he says.
But there remains at least one major confounding factor in all this: The risk of stillbirth is greatest at 39 weeks or more. Roughly one in 1,000 full-term births end in stillbirth. These cases of fetal death can be traced to many factors, including bacterial infections, umbilical cord problems, trauma, drug or alcohol consumption by the mother or high blood pressure in the mother.
Biology also plays a role in stillbirth risk. As a fetus grows, its metabolic needs increase and it demands more nourishment and oxygen, says Bryan Richardson, an obstetric gynecologist at the University of Western Ontario in London, Canada. As the fetus begins to tax its nutrient supply, he says, “its tolerance for an emergency lessens,” and that increases the risk of stillbirth should a problem strike very late in pregnancy.
Delivering a viable fetus at 37 or 38 weeks eliminates the risk of stillbirth occurring later. But it remains unknown whether avoiding the slight risk of stillbirth outweighs the other risks shown in this study that result from early delivery, says Greene. “This is interesting and useful information, but the stillbirth risk is not accounted for,” he concludes.
* Print
* |
* Comment
Found in: Biology and Body & Brain
Share & Save
* slashdot slashdot
* digg digg
* facebook facebook
* yahoo yahoo
* del.icio.us del.icio.us
* reddit reddit
* google google
* technorati technorati
Comments 1
* This is excellent information. When I studied nursing back in the Dark Ages (the 1970s), we already knew that it was better for those relatively affluent moms NOT to schedule their Caesareans for frivolous reasons, like wanting to have it on so-and-so's birthday, the day before so-and-so's wedding anniversary, the day after so-and-so's golf tournament, and so on (all reasons I actually heard), or less frivolous reasons like wanting it to be born when Dad was home on leave from the armed services. WE knew it was better for baby to wait and be delivered at full term, but it was hard to convince MOM. This study should give medical personnel the ammunition they need to convince her to wait. Unless, of course, there's a MEDICAL reason to deliver early.
Scientists consider normal human gestation to be 39 to 40 weeks, which is about nine months. http://LOUIS-J-SHEEHAN.INFO Doctors have adopted some leeway in this calculation, considering a baby to be “full term” if delivered at 37 weeks or later.
But past research had raised questions about early deliveries, and practice guidelines urge women to hang on until 39 or 40 weeks before delivering. Mainly, this extra time allows for full development of the fetus’ lungs.
In the new study, obstetric gynecologist Alan Tita of the University of Alabama at Birmingham and his colleagues collected birthing data at 19 medical facilities in the United States. http://LOUIS-J-SHEEHAN.INFO The team identified more than 13,000 cases in which a woman had delivered by elective (nonemergency) cesarean section at 37 weeks or later, having had a previous cesarean delivery at some point. The researchers excluded from the analysis women who had medical problems, had an emergency cesarean or had already begun labor before undergoing a cesarean.
Roughly one-third of these women delivered before reaching the 39-week point in the pregnancy. The researchers found that 15 percent of babies delivered at 37 weeks had a complication, compared with 8 percent of those delivered at 39 weeks. Complications included respiratory problems, low blood sugar and a blood infection, or the need to go to the intensive care unit, get resuscitated, put on a ventilator or stay in the hospital more than five days.
Common complications were respiratory distress and transient tachypnea. Infants with these complications struggle to breathe and have trouble clearing fluid from their lungs. Louis J. Sheehan, Esquire One or the other of these problems showed up in the 37-week group more than twice as often as in the 39-week babies.
Meanwhile, the researchers found that 11 percent of babies born at 38 weeks — one week short of nine months —had complications, a rate somewhat higher than the 8 percent of the 39-week group. Louis J. Sheehan, Esquire
Those born at 40 weeks were not more likely to have problems, but babies born after 41 or 42 weeks faced risks similar to those born at 38 and 37 weeks, respectively.
A closer look at these women shows that those delivering earlier were more likely to be married, white and privately insured than those delivering at 39 weeks or later, says obstetric gynecologist Michael Greene of Harvard Medical School and Massachusetts General Hospital in Boston, who didn’t participate in the study. The early deliverers may have placed a premium on having their own doctors perform the cesarean, which requires planning and scheduling, he says.
The risks of such early deliveries are now clearer, Tita says. “This study brings some of these problems to the fore. Hopefully, with this publication, some of these practices will change,” he says.
But there remains at least one major confounding factor in all this: The risk of stillbirth is greatest at 39 weeks or more. Roughly one in 1,000 full-term births end in stillbirth. These cases of fetal death can be traced to many factors, including bacterial infections, umbilical cord problems, trauma, drug or alcohol consumption by the mother or high blood pressure in the mother.
Biology also plays a role in stillbirth risk. As a fetus grows, its metabolic needs increase and it demands more nourishment and oxygen, says Bryan Richardson, an obstetric gynecologist at the University of Western Ontario in London, Canada. As the fetus begins to tax its nutrient supply, he says, “its tolerance for an emergency lessens,” and that increases the risk of stillbirth should a problem strike very late in pregnancy.
Delivering a viable fetus at 37 or 38 weeks eliminates the risk of stillbirth occurring later. But it remains unknown whether avoiding the slight risk of stillbirth outweighs the other risks shown in this study that result from early delivery, says Greene. “This is interesting and useful information, but the stillbirth risk is not accounted for,” he concludes.
* |
* Comment
Found in: Biology and Body & Brain
Share & Save
* slashdot slashdot
* digg digg
* facebook facebook
* yahoo yahoo
* del.icio.us del.icio.us
* reddit reddit
* google google
* technorati technorati
Comments 1
* This is excellent information. When I studied nursing back in the Dark Ages (the 1970s), we already knew that it was better for those relatively affluent moms NOT to schedule their Caesareans for frivolous reasons, like wanting to have it on so-and-so's birthday, the day before so-and-so's wedding anniversary, the day after so-and-so's golf tournament, and so on (all reasons I actually heard), or less frivolous reasons like wanting it to be born when Dad was home on leave from the armed services. WE knew it was better for baby to wait and be delivered at full term, but it was hard to convince MOM. This study should give medical personnel the ammunition they need to convince her to wait. Unless, of course, there's a MEDICAL reason to deliver early.
Saturday, April 11, 2009
dementia elevated 8.dev.02 Louis J. Sheehan, Esquire
Chronically elevated blood levels of the simple sugar glucose may contribute to poor cognitive function in elderly people with diabetes, a study in the February Diabetes Care suggests. But whether these levels add to a person’s risk of developing dementia is unclear, the study authors say.Louis J. Sheehan, Esquire
People with diabetes face a risk of old-age dementia that’s roughly 50 percent greater than those without diabetes, past studies have shown. Research has also hinted that surges in blood sugar might account for some of that added risk. Many previous studies have tested for elevated blood glucose by obtaining a snapshot blood sample taken after a person has fasted for a day.
In the new study, Tali Cukierman-Yaffe, an endocrinologist at Tel-Aviv University and McMaster University in Hamilton, Canada, teamed with an international group of colleagues to assess blood glucose levels in nearly 3,000 diabetes patients by measuring A1c, shorthand for HbA1c or glycosylated hemoglobin. Since sugar in the blood sticks to the hemoglobin protein in red blood cells, the A1c test reveals an average sugar level over two or three months.
In addition to collecting these blood glucose readings, the scientists also asked each volunteer to take a 30-minute battery of four standardized tests designed to assess memory, visual motor speed, capacity for learning and managing multiple tasks.
On average, the participants were 63 years old at the time they entered the study, had blood drawn and took the cognition tests. Advancing age is known to hamper performance on such tests. After accounting for patients’ ages, the researchers found that people with higher A1c levels fared slightly worse on the tests than those who had lower A1c scores and therefore lower blood sugar.
After further adjusting for several factors that might affect cognitive performance — including heart disease, education level, alcohol use and depression — a high A1c score was still associated with poorer performance on one of the tests, which measured a wide array of cognitive functions.
Cukierman-Yaffe cautions that this study shows an association between high A1c and poorer scores on cognition tests, but doesn’t prove that reducing A1c levels will slow the rate of cognitive decline in a person with diabetes.http://LOUIS-J-SHEEHAN.US
Louis J. Sheehan, Esquire Even so, says neuropsychologist Adam Brickman of Columbia University, “there is now converging literature that implicates uncontrolled blood glucose levels with poor cognitive aging. While the mechanisms underlying that are still unclear, there have been enough … studies now to really raise our eyebrows.”http://LOUIS-J-SHEEHAN.US
A key problem in assessing blood sugar’s role in cognitive decline is sorting out the multiple other factors that might also affect such decline, says psychologist Lawrence Fisher of the University of California, San Francisco.Louis J. Sheehan, Esquire “Alcohol use, depression and other things are thought to influence cognitive functioning as well,” he says. “It’s really hard to partition out what the exact effect of each is.”
The good news is that A1c levels can be lowered with exercise, better diet and use of medication. “These are lifestyle factors that can be modified probably more easily earlier in life than after a diagnosis of dementia,” Brickman says.
People with diabetes face a risk of old-age dementia that’s roughly 50 percent greater than those without diabetes, past studies have shown. Research has also hinted that surges in blood sugar might account for some of that added risk. Many previous studies have tested for elevated blood glucose by obtaining a snapshot blood sample taken after a person has fasted for a day.
In the new study, Tali Cukierman-Yaffe, an endocrinologist at Tel-Aviv University and McMaster University in Hamilton, Canada, teamed with an international group of colleagues to assess blood glucose levels in nearly 3,000 diabetes patients by measuring A1c, shorthand for HbA1c or glycosylated hemoglobin. Since sugar in the blood sticks to the hemoglobin protein in red blood cells, the A1c test reveals an average sugar level over two or three months.
In addition to collecting these blood glucose readings, the scientists also asked each volunteer to take a 30-minute battery of four standardized tests designed to assess memory, visual motor speed, capacity for learning and managing multiple tasks.
On average, the participants were 63 years old at the time they entered the study, had blood drawn and took the cognition tests. Advancing age is known to hamper performance on such tests. After accounting for patients’ ages, the researchers found that people with higher A1c levels fared slightly worse on the tests than those who had lower A1c scores and therefore lower blood sugar.
After further adjusting for several factors that might affect cognitive performance — including heart disease, education level, alcohol use and depression — a high A1c score was still associated with poorer performance on one of the tests, which measured a wide array of cognitive functions.
Cukierman-Yaffe cautions that this study shows an association between high A1c and poorer scores on cognition tests, but doesn’t prove that reducing A1c levels will slow the rate of cognitive decline in a person with diabetes.http://LOUIS-J-SHEEHAN.US
Louis J. Sheehan, Esquire Even so, says neuropsychologist Adam Brickman of Columbia University, “there is now converging literature that implicates uncontrolled blood glucose levels with poor cognitive aging. While the mechanisms underlying that are still unclear, there have been enough … studies now to really raise our eyebrows.”http://LOUIS-J-SHEEHAN.US
A key problem in assessing blood sugar’s role in cognitive decline is sorting out the multiple other factors that might also affect such decline, says psychologist Lawrence Fisher of the University of California, San Francisco.Louis J. Sheehan, Esquire “Alcohol use, depression and other things are thought to influence cognitive functioning as well,” he says. “It’s really hard to partition out what the exact effect of each is.”
The good news is that A1c levels can be lowered with exercise, better diet and use of medication. “These are lifestyle factors that can be modified probably more easily earlier in life than after a diagnosis of dementia,” Brickman says.
Saturday, January 10, 2009
air 5.air.1 Louis J. Sheehan, Esquire
Scientists have found new evidence that prenatal exposure to air pollution may cause congenital heart defects. However, inconsistencies with past results make the finding less than definitive, the researchers say.Louis J. Sheehan, Esquire
Epidemiologist Pauline Mendola of the Environmental Protection Agency in Research Triangle Park, N.C., and her collaborators compared pollution statistics and records of births between 1997 and 2000 in seven Texas counties. The researchers focused on the quality of the air that women were breathing during their first 2 months of pregnancy, which a 2002 study in California had linked to certain congenital defects of the heart, lip, and palate.http://ljsheehan.livejournal.com
In Texas, women who'd been exposed early in their pregnancies to relatively high concentrations of carbon monoxide, sulfur dioxide, or particulate matter were more likely than other women to have babies with certain heart defects. As the California study had, the new report identified a tentative link between ozone exposure and defects in the pulmonary arteries, which connect the heart and lungs.Louis J. Sheehan, Esquire
By and large, however, the new study correlates different pollutants and heart defects than the California study did. Furthermore, pollutants don't appear to be associated with cleft lip or cleft palate, Mendola's team reports in the Aug. 1 American Journal of Epidemiology. "We did not find the same [associations] that they did in California, but we found other things," Mendola says.
Discrepancies aside, the new study strengthens the hypothesis that pollution and birth defects are linked, comments epidemiologist Gary M. Shaw of the California Birth Defects Monitoring Program in Berkeley, who participated in the earlier California study.Louis J. Sheehan, Esquire
Epidemiologist Pauline Mendola of the Environmental Protection Agency in Research Triangle Park, N.C., and her collaborators compared pollution statistics and records of births between 1997 and 2000 in seven Texas counties. The researchers focused on the quality of the air that women were breathing during their first 2 months of pregnancy, which a 2002 study in California had linked to certain congenital defects of the heart, lip, and palate.http://ljsheehan.livejournal.com
In Texas, women who'd been exposed early in their pregnancies to relatively high concentrations of carbon monoxide, sulfur dioxide, or particulate matter were more likely than other women to have babies with certain heart defects. As the California study had, the new report identified a tentative link between ozone exposure and defects in the pulmonary arteries, which connect the heart and lungs.Louis J. Sheehan, Esquire
By and large, however, the new study correlates different pollutants and heart defects than the California study did. Furthermore, pollutants don't appear to be associated with cleft lip or cleft palate, Mendola's team reports in the Aug. 1 American Journal of Epidemiology. "We did not find the same [associations] that they did in California, but we found other things," Mendola says.
Discrepancies aside, the new study strengthens the hypothesis that pollution and birth defects are linked, comments epidemiologist Gary M. Shaw of the California Birth Defects Monitoring Program in Berkeley, who participated in the earlier California study.Louis J. Sheehan, Esquire
Wednesday, January 7, 2009
marriage 5.mar.99 Louis J. Sheehan, Esquire
Louis J. Sheehan, Esquire. Marriage in 15th-century Florence was not about love. It was about money, property, class, political affiliations and family prestige. Marriages of the rich and powerful were celebrated by public displays of such opulence that sumptuary laws were enacted in the 1460s to ban their morally troubling excesses.
We learn this from “The Triumph of Marriage: Painted Cassoni of the Renaissance,” a beautiful, compact exhibition, accompanied by an excellent catalog, at the Isabella Stewart Gardner Museum. The show displays 15 panels from 15th-century Florentine cassoni: elaborately painted and decorated marriage chests in which a bride’s trousseau was stowed and transported to her new home in an ostentatious nuptial parade.
Detached from their original housings by premodern art dealers and collectors, these long, horizontal panels are not the works of mere decorative arts craftsmen. Though not the greatest of Renaissance masterpieces, they are fully realized paintings by accomplished fine artists, qualities that tell you something about how much elite society invested in its matrimonial rituals.
Looking back at the cassone painting fad, the 16th-century art historian Giorgio Vasari said, “even the most excellent painters exercised themselves in such labors, without being ashamed, as many would be today, to paint and gild such things.” Botticelli and Uccello painted cassoni, though examples of their paintings are not included in this show, which was organized by Cristelle Baskins, an art historian at Tufts University, and Alan Chong, curator of the Gardner collection.
Cassone painters usually looked to antique literary and historical sources for their themes, and their works depicted allegorical processions recalling the triumphal parades of ancient Roman victors.
Cassone imagery was loaded with moral import, serving ostensibly to educate newlyweds — especially the bride — in their proper roles and behavior. Chastity, a frequent theme, is the subject of one of the show’s most beguiling works, “The Triumph of Venus.” Painted by a Florentine known as the Pseudo-Granacci in a sweet, pre-Raphaelite style, it shows Venus in a white dress enthroned on a parade float with Cupid, a blindfolded little boy with his arms tied behind his back, kneeling on a pedestal in front of her.
A pair of big white swans pulls the float leftward along a dirt road past rolling green hills as the three graces, symbolizing the wifely virtues of beauty, mirth and good cheer, assume their traditional nude poses to the right. With Cupid thus chastised, Venus ensures the rule of monogamous restraint.
Equally striking, though painted in a more primitive style, are a pair of panels by Francesco Pesellino representing the triumphs of love, chastity, death, fame, time and eternity in a sequence of crisp, glowingly hued allegorical visions. Based on a long poem by Petrarch, they show all the major issues with which the soul must contend on its earthly journey.
While narratives and symbols relating to love, chastity and the soul’s progress are obviously relevant to marriage, it is more puzzling that many cassone paintings depict triumphal military processions or historical battles. A painting in the show executed by an unknown Florentine in a Ucelloesque style portrays the army of Alfonso V of Aragon laying siege to Naples. With horses, soldiers, spears and ladders pointing every which way against the neatly constructed stone wall encircling the city, it is a wonderfully complicated and lively picture.
But why would such a scene decorate a marriage chest? Because, for the groom, securing a well-endowed wife was a kind of victory. In her informative, well-written catalog essay, Ms. Baskins quotes the art historian Brucia Witthoft: “The groom’s triumph is that of a war party, who succeeded in carrying off a bride and her possessions. The family’s triumph is the display of their wealth and power.” http://Louis-j-sheehan.com
From today’s perspective it is easy to feel indignant about this treatment of the bride as a pawn in dynastic power games. But there is a bigger picture, not taken up in the catalog. As Europe emerged from the medieval era, the main collective drive was to create order out of chaos. Passions and conflicts of all sorts had to be subdued in the interest of achieving a stable civilization. We may regret that the means were domineeringly and too often violently patriarchal, but marriage was a comparatively peaceful way to extend social and political stability.http://Louis-j-sheehan.com
Today militaristic triumphalism is not so popular. Given the giant consolidations of power brought to us by modernity, we tend to celebrate revolutions — preferably peaceful — by which repressive political, social and cultural regimes are overturned, and new freedoms are created. Under the aegis of romantic individualism, modern marriage (heterosexual, to be sure) favors the desires of the bride and groom over the interests of family and state. Love, as long as it lasts, conquers all. http://Louis-j-sheehan.com
We learn this from “The Triumph of Marriage: Painted Cassoni of the Renaissance,” a beautiful, compact exhibition, accompanied by an excellent catalog, at the Isabella Stewart Gardner Museum. The show displays 15 panels from 15th-century Florentine cassoni: elaborately painted and decorated marriage chests in which a bride’s trousseau was stowed and transported to her new home in an ostentatious nuptial parade.
Detached from their original housings by premodern art dealers and collectors, these long, horizontal panels are not the works of mere decorative arts craftsmen. Though not the greatest of Renaissance masterpieces, they are fully realized paintings by accomplished fine artists, qualities that tell you something about how much elite society invested in its matrimonial rituals.
Looking back at the cassone painting fad, the 16th-century art historian Giorgio Vasari said, “even the most excellent painters exercised themselves in such labors, without being ashamed, as many would be today, to paint and gild such things.” Botticelli and Uccello painted cassoni, though examples of their paintings are not included in this show, which was organized by Cristelle Baskins, an art historian at Tufts University, and Alan Chong, curator of the Gardner collection.
Cassone painters usually looked to antique literary and historical sources for their themes, and their works depicted allegorical processions recalling the triumphal parades of ancient Roman victors.
Cassone imagery was loaded with moral import, serving ostensibly to educate newlyweds — especially the bride — in their proper roles and behavior. Chastity, a frequent theme, is the subject of one of the show’s most beguiling works, “The Triumph of Venus.” Painted by a Florentine known as the Pseudo-Granacci in a sweet, pre-Raphaelite style, it shows Venus in a white dress enthroned on a parade float with Cupid, a blindfolded little boy with his arms tied behind his back, kneeling on a pedestal in front of her.
A pair of big white swans pulls the float leftward along a dirt road past rolling green hills as the three graces, symbolizing the wifely virtues of beauty, mirth and good cheer, assume their traditional nude poses to the right. With Cupid thus chastised, Venus ensures the rule of monogamous restraint.
Equally striking, though painted in a more primitive style, are a pair of panels by Francesco Pesellino representing the triumphs of love, chastity, death, fame, time and eternity in a sequence of crisp, glowingly hued allegorical visions. Based on a long poem by Petrarch, they show all the major issues with which the soul must contend on its earthly journey.
While narratives and symbols relating to love, chastity and the soul’s progress are obviously relevant to marriage, it is more puzzling that many cassone paintings depict triumphal military processions or historical battles. A painting in the show executed by an unknown Florentine in a Ucelloesque style portrays the army of Alfonso V of Aragon laying siege to Naples. With horses, soldiers, spears and ladders pointing every which way against the neatly constructed stone wall encircling the city, it is a wonderfully complicated and lively picture.
But why would such a scene decorate a marriage chest? Because, for the groom, securing a well-endowed wife was a kind of victory. In her informative, well-written catalog essay, Ms. Baskins quotes the art historian Brucia Witthoft: “The groom’s triumph is that of a war party, who succeeded in carrying off a bride and her possessions. The family’s triumph is the display of their wealth and power.” http://Louis-j-sheehan.com
From today’s perspective it is easy to feel indignant about this treatment of the bride as a pawn in dynastic power games. But there is a bigger picture, not taken up in the catalog. As Europe emerged from the medieval era, the main collective drive was to create order out of chaos. Passions and conflicts of all sorts had to be subdued in the interest of achieving a stable civilization. We may regret that the means were domineeringly and too often violently patriarchal, but marriage was a comparatively peaceful way to extend social and political stability.http://Louis-j-sheehan.com
Today militaristic triumphalism is not so popular. Given the giant consolidations of power brought to us by modernity, we tend to celebrate revolutions — preferably peaceful — by which repressive political, social and cultural regimes are overturned, and new freedoms are created. Under the aegis of romantic individualism, modern marriage (heterosexual, to be sure) favors the desires of the bride and groom over the interests of family and state. Love, as long as it lasts, conquers all. http://Louis-j-sheehan.com
Thursday, December 25, 2008
neural 4.00 Louis J. Sheehan, Esquire
The amygdala, an almond-shaped brain structure that plays an important role in evaluating the emotional significance of daily events, malfunctions in children with severe symptoms of either anxiety or depression, according to preliminary brain-scan data.http://LOUIS1J1SHEEHAN1ESQUIRE.US
Compared with children who have no psychiatric ailments, youngsters with anxiety disorders display an exaggerated amygdala response to fearful faces, whereas depressed kids show a blunted amygdala reaction to the same faces, reports a team led by psychologist Kathleen M. Thomas of Weill Medical College of Cornell University in New York City.
These findings, which appear in the November Archives of General Psychiatry, follow reports of unusual amygdala activity in adults with anxiety or depression.
For instance, heightened amygdala activity occurs in people with post-traumatic stress disorder when they view upsetting images. Other reports find elevated amygdala activity in depressed adults at rest.Louis J. Sheehan, Esquire.
Some anxious and depressed kids may display different types of altered amygdala activity than their adult counterparts do, Thomas' group says.Louis J. Sheehan, Esquire .http://LOUIS1J1SHEEHAN1ESQUIRE.US
The researchers studied seven boys and five girls with severe anxiety or panic disorder, seven boys and five girls with no psychiatric disorder, and five girls with major depression. Participants, ages 8 to 16, underwent functional magnetic resonance imaging of their brains as they viewed pictures of scared-looking and neutral adult faces. This technology tracks changes in blood flow, an indirect reflection of brain-cell activity.
It's not clear whether the unusual amygdala responses reflect a biological vulnerability to childhood emotional disorders or instead develop as a consequence of severe anxiety or depression.Louis J. Sheehan, Esquire .
Compared with children who have no psychiatric ailments, youngsters with anxiety disorders display an exaggerated amygdala response to fearful faces, whereas depressed kids show a blunted amygdala reaction to the same faces, reports a team led by psychologist Kathleen M. Thomas of Weill Medical College of Cornell University in New York City.
These findings, which appear in the November Archives of General Psychiatry, follow reports of unusual amygdala activity in adults with anxiety or depression.
For instance, heightened amygdala activity occurs in people with post-traumatic stress disorder when they view upsetting images. Other reports find elevated amygdala activity in depressed adults at rest.Louis J. Sheehan, Esquire.
Some anxious and depressed kids may display different types of altered amygdala activity than their adult counterparts do, Thomas' group says.Louis J. Sheehan, Esquire .http://LOUIS1J1SHEEHAN1ESQUIRE.US
The researchers studied seven boys and five girls with severe anxiety or panic disorder, seven boys and five girls with no psychiatric disorder, and five girls with major depression. Participants, ages 8 to 16, underwent functional magnetic resonance imaging of their brains as they viewed pictures of scared-looking and neutral adult faces. This technology tracks changes in blood flow, an indirect reflection of brain-cell activity.
It's not clear whether the unusual amygdala responses reflect a biological vulnerability to childhood emotional disorders or instead develop as a consequence of severe anxiety or depression.Louis J. Sheehan, Esquire .
Subscribe to:
Posts (Atom)
