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Biomedical subjects

D Giannini

Publications and source records attributed to D Giannini.

60 records · Page 4Linked to original sources
PubMed1993

Bronchial hyperresponsiveness and toluene diisocyanate. Long-term change in sensitized asthmatic subjects.

Long-term change in nonspecific and specific bronchial hyperresponsiveness was studied in 16 subjects with asthma induced by toluene diisocyanate (TDI). A significant positive correlation between months of follow-up and provocative dose inducing a 20 percent fall in FEV1 (PD20FEV1) methacholine was observed in 5 of 16 subjects. In 4 of these 5 subjects, a PD20FEV1 > 1 mg of methacholine was observed 30 to 48 months after the end of TDI exposure. In most subjects, nonspecific bronchial hyperresponsiveness did not change. Nine of 16 subjects became nonresponsive to TDI at follow-up examination, but only 3 of these showed a significant increase in PD20FEV1 methacholine. Seven subjects were still responsive to TDI. Recovery from TDI-induced asthma can occur and only after long-term work cessation. Nonspecific bronchial hyperresponsiveness to methacholine can persist even in the absence of bronchial hyperresponsiveness to TDI, suggesting permanent chronic damage to mechanisms controlling airway tone.

Adult↗
PubMedDate not supplied

Effects of fatiguing exercise on high-energy phosphates, force, and EMG: evidence for three phases of recovery.

Experiments were designed to evaluate the relative contribution of impulse propagation failure, high-energy phosphate depletion, lowered pH, and impaired excitation-contraction coupling to human muscle fatigue and recovery. 31P nuclear magnetic resonance spectroscopy measurements were made on adductor pollicis muscle, together with simultaneous measurements of M-wave, force, and rectified integrated EMG (RIEMG). During fatigue, maximum voluntary contraction force (MVC) fell by 90%, pH fell from 7.1 to 6.4, and phosphocreatine was almost totally depleted. Neuromuscular efficiency (NME = force/RIEMG) was reduced to 40% of control at the end of the fatiguing contraction, and the M wave was reduced in amplitude and prolonged in duration. Following exercise, the M wave returned to normal within 4 minutes. pH, high-energy phosphates, and MVC recovered within 20 minutes. By contrast, neuromuscular efficiency did not recover within 60 minutes. These findings indicate three different components of fatigue. The first is reflected by the altered M wave and indicates impaired muscle membrane excitation and impulse propagation. The second, associated with reduced MVC, correlates with the metabolic state of the muscle (PCr and pH). The third, indicated by reduced NME, is independent of changes in high-energy phosphates and pH and is probably due to impaired excitation-contraction coupling.

Adolescent↗
PubMedDate not supplied

Abnormal migratory activity of peripheral neutrophils from asthmatic patients and its modulation by inhaled glucocorticoids.

In order to investigate if bronchial asthma is associated with enhanced markers of activation in peripheral neutrophils, the migratory capacity of neutrophils in venous blood was measured by means of the Boyden chamber technique in 29 subjects with bronchial asthma of differing severity. Random migration (random motility), but not locomotion toward 10% Escherichia coli supernatant as chemoattractant (chemotaxis), was increased in asthmatic subjects with respect to 11 normal subjects (98 +/- 20 microns vs. 85 +/- 6 microns; p < 0.05). When asthmatic subjects were subdivided into groups of different disease severity, subjects with mild and mild to moderate asthma showed significantly higher values for random motility and chemotaxis than normal subjects; on the other hand, subjects with more severe disease showed the lowest values for migratory activity. No correlation was found between migratory activity and clinical findings of asthma, except for baseline FEV1 (% of the predicted value), which showed a slight but significant positive correlation with chemotaxis (r = 0.44, p < 0.05). Subjects with atopic or occupational asthma had higher values for migratory activity than subjects with nonallergic asthma. Thirteen asthmatic subjects repeated all evaluations after 1 month of treatment with high doses of inhaled glucocorticoids (beclomethasone dipropionate 1500 micrograms/day). Random motility (95 +/- 24 microns vs. 75 +/- 15 microns; p < 0.05) and chemotaxis (130 +/- 22 microns vs. 105 +/- 25 microns; p < 0.05) were significantly reduced after treatment, as well as the symptom score; on the other hand, symptom score but not bronchial hyperresponsiveness to methacholine challenge significantly changed.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗