Respiratory flutter syndrome that occurs in neonates
Respiratory flutter syndrome that occurs during the first month of life could be a more frequent cause of respiratory failure in newborns than previously recognized. Researchers from Johns Hopkins Hospital describe treatment for three neonates who had respiratory failure, shortly after birth, associated with respiratory flutter. Their condition required temporary ventilatory support. Respiratory flutter involves rapid rhythmic respiratory muscle contractions of the diaphragm and intercostal muscles superimposed on a normal respiratory cycle. The diaphragm is the major muscle of breathing, and its respiratory action is augmented by other muscle groups, including the intercostal muscles attached to the ribs. The researchers said that infant breathing, as compared with that of adults, relies more heavily on a larger contribution from the diaphragm. The respiratory flutter of the three babies was confined to the inspiration phase of the breathing cycle. Continuous positive airway pressure normalized the breathing pattern in one infant, and temporarily improved the ventilation in the other two by reducing the amount of respiratory flutter. Chlorpromazine, a major tranquilizer that also stops nausea and vomiting, halted respiratory flutter within 12 hours in all infants, and permitted them to be weaned off of ventilatory support within a few hours.
The study appears in the first of two October issues of the American Thoracic Society peer-reviewed American Journal of Respiratory and Critical Care Medicine.
Tuberculosis 'microepidemic' caused by Beijing strain
A virulent Beijing tuberculosis (TB) bacterial strain, one that was not previously identified on-site and that was brought in by a Liberian refugee in 1993, exploded into a “microepidemic” over a 4-year period to become the most common cause of the disease on Spain’s Gran Canaria Island. The researchers report that a single Liberian refugee spawned 75 new cases which accounted for 27 percent of all strains in 1996 on Gran Canaria. The isolate was not present on the island in surveys conducted from 1991 to 1992. Among the 75 cases of the Beijing TB strain identified, linkage was established by molecular testing in 51 (68 percent). The researchers suggested that this strain could be responsible for “important components of the worldwide resurgence of tuberculosis, and may represent an epidemic within the larger tuberculosis epidemic.”
The research appears in the first of two October issues of the American Thoracic Society peer-reviewed American Journal of Respiratory and Critical Care Medicine.
Exercise-induced oxidative stress for chronic obstructive pulmonary disease patients
In an editorial directed at a scientific study on endurance training for patients with chronic obstructive pulmonary disease (COPD), the author concludes that the “research results call into question the basic strategy of exercise training for patient rehabilitation.” He discusses research conducted by Spanish investigators that shows redox (oxidation-reduction) regulation is abnormal in the muscles of COPD patients, but can be strengthened in normal subjects. Skeletal muscles at work are exposed to increased concentrations of reactive oxygen species that can inhibit muscular force, contribute to premature muscle fatigue, and promote muscle atrophy. Through a complex enzymatic process, antioxidants begin to buffer the oxidants when they reach a certain level in the muscles. The researchers tried to prove that the antioxidant buffering capacity could be enhanced by vigorous exercise training in the muscles of 17 COPD patients and 5 age-matched healthy controls. After 8 weeks of high-intensity training, the controls showed increased efficacy of antioxidant buffering, while those who had COPD demonstrated no such benefit. (Both groups showed similar levels at rest and after moderate exercise prior to the beginning of the 8-week vigorous training schedule.) The data indicate that the muscles of COPD patients could be more susceptible to exercise-induced oxidative stress. The editorial calls for an additional study to determine the extent to which training induces antioxidant deficiency, the antioxidant pathways that are affected, and the degree to which antioxidant deficiency is linked to a specific training program. Then, perhaps, tailored training programs could be designed for COPD patients. Also, it might be possible to provide nutritional and/or pharmacologic supplements that limit oxidative stress in working muscles.
The research and editorial appear in the first of two October issues of the American Thoracic Society peer-reviewed American Journal of Respiratory and Critical Care Medicine.
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Journal
American Journal of Respiratory and Critical Care Medicine