All asthma and respiratory conditions stories

Researchers uncover cause of asthma

70652986 — Mon, 26 Mar 2007 06:25:27 -0400

Medical experts have been baffled by what causes asthma. Most of them favor the idea that it stems from "helper" cells that have gone awry. But researchers at Harvard Medical School have come up with convincing evidence that the answer lies in a special type of natural "killer" cell.

We were very, very surprised," admits Dale Umetsu, a professor of pediatrics at the Medical School and at Harvard-affiliated Children's Hospital in Boston. "People have been confused about which cells in the lungs are responsible for all these years. Now, we have to rethink the results of so many studies. Our new findings were totally unexpected."

Simple tools can reduce transmission

50443248 — Tue, 24 Jul 2007 16:42:50 -0400

Viral upper respiratory and gastrointestinal infections are the two most common illnesses that occur in children enrolled in day care, and secondary attack rates within families can be as high as 27 percent for respiratory illnesses and 70 percent for gastroenteritis.
New research published in the April issue of Pediatrics shows that in homes with children enrolled in day care, several misconceptions regarding illness transmission may be contributing to the spread of these diseases.

Mechanism helps describe how airways respond to constriction

70652986 — Mon, 26 Mar 2007 05:35:52 -0400

In asthma, substances such as allergens irritate the airways and cause the smooth muscle cells around them to contract. With repeated attacks, lung tissues become damaged from cycles of inflammation and repair. Scar tissue forms, which forces the airways to change their shape, or remodel. The airway walls become abnormally thick, potentially interfering with breathing. Figuring out how to stop the thickening is a common goal among asthma experts. Now, Harvard School of Public Health Assistant Professor Daniel Tschumperlin and his colleagues have suggested a possible additional explanation for why the airways thicken, providing another research target. The work required the expertise of physicians, cell biologists, physiologists, engineers, physicists, and mathematicians, representing several institutions. Tschumperlin developed an in vitro cell culture model to mimic the conditions of the human lung when it constricts, and he detected the activation of a specific signal transduction pathway. To get a better idea of what was going on at the cell surface, Tschumperlin collaborated with groups headed by MIT biomedical engineers Peter So and Roger Kamm. The MIT scientists had unique, cutting-edge imaging tools that allowed them to reconstruct three-dimensional microscopic structures of living epithelial cells, or cells that line the airways. Another well-known MIT bioengineer, Douglas Lauffenburger, and his team worked on pinpointing the specifics of the biochemical pathway that had been detected. He developed a quantitative model to calculate the distribution of proteins among epithelial cells when the airway constricts.

Climate, asthma connected, according to research

70652986 — Mon, 26 Mar 2007 05:30:54 -0400

Christine Rogers, a research associate at the Harvard School of Public Health, measures particulates - pollen grains and fungal spores - in outdoor air and correlates levels with asthma events. She also examines how those particulate levels might change over time because of global warming. "One of the most predictable effects of global warming is that CO2 is going to increase," she says. "But also, seasonality is going to change. Springs will come earlier, lengthening our growing seasons. Both of these trends affect plants' biomass, making them larger at maturity and, logically, able to produce more pollen." To measure the effects of global warming on pollen production, Rogers and her colleagues forced ragweed plants to germinate two and four weeks earlier than they normally would, simulating the early springs that are likely to become more frequent. Half of each plant group was exposed to the normal, ambient CO2 level of 350 parts per million, and the other half to double that amount. Rogers found that total pollen production under ambient CO2 was higher in the plants grown in early spring than in those grown later. At high CO2 levels, however, plants grown later had higher total pollen production than those at ambient CO2.

Bottle-feeding before bed time may increase risk of childhood asthma

70652986 — Mon, 26 Mar 2007 05:26:20 -0400

Nearly one in 13 children in America has asthma. The National Institutes of Health reports that the prevalence of asthma around the world has doubled in the last 15 years, increasing 160 percent among pre-school age children. Asthma is the third leading cause of hospitalization among children under age 15 and accounts for more than 10 million missed school days annually. Researchers found that bottle feeding in the bed or crib before sleep time during the first year of life was a risk factor for asthma and recurrent wheezing at five years of age. It also appeared to be a risk factor for wheezing between the ages of one to five years. "For infants in a high-risk group, we found that when and how they are fed influence the onset of wheezing and asthma," said Juan Celedon of Brigham and Women's Hospital. "There is a significant relationship between the number of times children are bottle fed in the crib or bed prior to sleep time and the occurrence of wheezing during their first five years."

Ban on coal burning in Dublin cleans the air, reduces death rates

70652986 — Mon, 26 Mar 2007 05:24:09 -0400

In the 1980s, Dublin's air quality suffered as people switched from oil to cheaper and more available coal for home and water heating. On Sept. 1, 1990, the Irish government banned the sale and distribution of bituminous coals within the city of Dublin. This offered researchers a unique opportunity to assess the effects of particulate pollution on mortality and the general population.

Battling toxic molds

70652986 — Mon, 26 Mar 2007 05:23:26 -0400

Molds are found in all kinds of environments. Estimates of the number of kinds of molds range from tens of thousands to more than 300,000, with more than 1,000 species known to typically grow indoors, according to the Centers for Disease Control and Prevention. While many molds appear to be benign to humans -- and some, such as the kind that produces penicillin, are beneficial -- several species are considered to be potent toxins. Questions raised by molds interest Mike Muilenberg, research associate and instructor in the Department of Environmental Health at Harvard's School of Public Health. As part of a series of studies on indoor allergens, Muilenberg is looking at the relationship between mold and health.

Maternal history influences risk of asthma in children exposed to cats

70652986 — Mon, 26 Mar 2007 05:24:51 -0400

Recent studies have gathered evidence that cat exposure during infancy can be protective against asthma. Research at Brigham and Women's Hospital confirmed these findings in all but one situation: when the child's mother has asthma. Researchers found that in a group of children with non-asthmatic mothers, those exposed to a cat were 40 percent less likely to experience persistent wheezing as compared to those with no cat exposure. Among children with a maternal history of asthma, the risk of wheezing associated with exposure to a cat increased with age.The findings suggest that children of asthmatic mothers become more readily sensitized to cat allergen and wheeze when exposed to it. "This research reinforces our knowledge that for the vast majority of children, having a cat in the home during their developmental years can be beneficial by protecting against asthma and allergies," said Juan Celedon, lead author of the study. "It is only among a high-risk group - children with a maternal history of asthma and perhaps, those whose mothers are allergic to cats - that exposure to a cat can negatively impact respiratory health." The study was supported by the National Institutes of Health.

Harvard researchers take aim at asthma

70652986 — Mon, 26 Mar 2007 05:21:20 -0400

Asthma is one of the most common chronic conditions in America, afflicting about 15 million people and causing 5,000 deaths annually, according to the National Institutes of Health. Asthma rates have been on the increase, rising by 75 percent from the early 1980s to the mid-1990s. Asthma disproportionately affects children and African-Americans, and is especially prevalent in low-income populations. The prevalence of asthma in Boston's neighborhoods reflects national trends with higher rates in poorer neighborhoods. The rates of asthma hospitalization in Boston's Roxbury section between 1994 and 1997 were the highest in the city, about six to eight times that in wealthier Back Bay.

Black, Latino children with asthma receive lesser standard of care

70652986 — Mon, 26 Mar 2007 07:30:15 -0400

Led by Tracy Lieu, associate professor of ambulatory care and prevention at Harvard Pilgrim Health Care and Harvard Medical School, the researchers interviewed parents of children with asthma who were insured by Medicaid programs.

Of the children, 38 percent were black, 19 percent Latino, and 31 percent white. The researchers studied the effects of ethnicity and the effects of familial factors.

Mouse model devised that develops asthma

70652986 — Mon, 26 Mar 2007 05:18:44 -0400

A Harvard research team led by Laurie Glimcher, Irene Heinz Given professor of immunology at the Harvard School of Public Health and a Harvard Medical School professor of medicine, two years ago discovered a molecule that they named T-bet. T-bet seemed to help control the immune system response by determining the actions of helper T cells, which are orchestrators of the immune response to disease. Glimcher's team studied mice that were engineered to lack T-bet. The mice, they found, had an uneven immune system response. Furthermore, the mice spontaneously developed the symptoms of asthma. The finding by Glimcher and her team helps to prove the case for T-bet as an important therapeutic target in several diseases, and also provides a new model for studying asthma.

Breathing new life into asthma therapy

70652986 — Mon, 26 Mar 2007 05:13:21 -0400

Asthma attacks have lasting effects because the lungs' most delicate airways can become scarred. This makes future attacks all the worse. Researchers at Harvard Medical School have looked at what happens during asthma attacks, and believe that the damage to airways can be prevented or lessened by prescribing muscle relaxants in addition to anti-inflammatory steroids. Prescribing muscle relaxants is actually an old asthma therapy that was discarded two decades ago in favor of anti-inflammatory steroid treatments. The supplanting of one therapy by another has caused some physicians in the United States to resist the idea of combining the drugs, though such combined therapies — steroids and muscle relaxants in the same inhaler — are already used in Europe.

Workers in buildings with less fresh air more likely to call in sick

70652986 — Mon, 26 Mar 2007 05:06:30 -0400

Donald Milton, associate professor in the Department of Environmental Health at the Harvard School of Public Health, hypothesized that the nature of the air that employees breathe affects how often they call in sick. In 1994, Milton and two colleagues measured ventilation rates in 40 buildings owned by Polaroid in Massachusetts with 115 independently ventilated work areas. They quantified air supply as moderate or high and then analyzed the absences of more than 3,700 employees to see who had called in sick and in which areas they worked. After noting a correlation between absences and the amount of ventilation in work areas, the researchers narrowed their focus to 600 office workers because they were less likely to be exposed to airborne irritants than those employed in manufacturing areas. The researchers found that office workers employed in areas that were moderately ventilated were 53 percent more likely to take time off due to illness than their colleagues in highly ventilated areas. Increasing ventilation may have prevented 35 percent of the absences, reported the researchers.

Air pollution deadlier than previously thought

70652986 — Mon, 26 Mar 2007 05:04:54 -0400

The idea that air pollution is harmful is hardly new. However, critics of the previous research of Joel Schwartz, associate professor of environmental health at the Harvard School of Public Health, and other air pollution researchers have claimed that those who die from air pollution are the very ill who would have died within a few days in any case. This notion is sometimes referred to as "harvesting." Using a statistical analysis that can factor out expected deaths, Schwartz debunked this argument in a study, "Harvesting and Long Term Exposure Effects in the Relations Between Air Pollution and Mortality" in the March 1, 2000, issue of the American Journal of Epidemiology. If it were true that people who died from air pollution would have died soon anyway, reasoned Schwartz, then there should be a correspondence between an increase in death rates during or immediately following a period of air pollution and a decrease in death rates a few days later. But it doesn't work that way. "Unfortunately, it doesn't work like that," said Schwartz.