Biomedical subjects

R G Bhagat

Publications and source records attributed to R G Bhagat.

4 recordsLinked to original sources

PubMed1985

Effect of corticosteroids on bronchial responsiveness to methacholine in asthmatic children.

To elucidate the effects of corticosteroids on nonspecific bronchial reactivity in asthmatic children, inhaled challenges with methacholine were conducted in 10 atopic asthmatic subjects (9 to 15 yr of age) before and after consecutive week-long trials of daily orally administered placebo and prednisone (60 mg/day). Pharmacologic bronchial sensitivity was evaluated as the log dose of methacholine producing a 20% fall in FEV1 (PD20-FEV1). The week-long trial of placebo had no effect on either baseline lung function or PD20-FEV1. On the other hand, after the 1-wk course of prednisone: (1) both baseline FEV1 and FEF25-75 systematically improved in the patients who initially had (i.e., before prednisone) lower values, and (2) PD20-FEV1 significantly increased (p less than 0.001) in all the subjects studied. The magnitude of increase in PD20-FEV1 after prednisone was significantly inversely related (i.e., inverse hyperbola) to the initial degree of airway obstruction (i.e., FEV1) obtained prior to prednisone treatment. Moreover, whereas 6 of 10 patients only minimally changed their baseline FEV1 after prednisone, collectively for all the subjects, the percent increase in PD20-FEV1 after prednisone was directly related (correlation coefficient, 0.70; p less than 0.05) to the corresponding percent increase in baseline FEV1 after prednisone. These findings demonstrate that after a week-long course of high-dose prednisone therapy: (1) a significant reduction occurs in bronchial sensitivity to inhaled methacholine in the asthmatic child, and (2) the degree of diminution in airway sensitivity to methacholine is inversely related to the patient's baseline status of airway obstruction.

Adolescent↗

PubMed1985

The late asthmatic response.

Since LARs are associated with increases in airways reactivity, their significance may go well beyond the increase in symptoms due just to the allergen exposure. This is especially true since the increase in non-specific airways reactivity can last for weeks after a single exposure to allergen. Every effort should be made to search for possible allergic triggers in patients suspected to have LARs. Careful attention to historical information and skin test reactivity are critical in this evaluation. In situations where this approach is not revealing and where serious concerns remain about potential environmental triggers, a bronchial challenge to the suspected antigen can be considered. Since the nonspecific airways reactivity in patients with LAR may possibly be due to inflammation in the airways, the potential risk of transient induction of airways inflammation must be carefully weighed against the value of information that can be obtained from this procedure. Bronchial challenge should be performed only in an inpatient setting by experienced personnel under the supervision of a physician. A full explanation of the potential risks and benefits of this type of evaluation must be given to the patient and family. Treatment is primarily directed at allergen avoidance with use of a prophylactic drug, such as cromolyn sodium, when allergen avoidance is not possible.

Allergens↗

PubMed1984

Comparison of responsiveness to methacholine, histamine, and exercise in subgroups of asthmatic children.

Nonspecific bronchial reactivity, involving inhaled challenges with methacholine and histamine and treadmill exercise challenge, were compared in 2 groups of steroid-requiring asthmatic children (9 to 15 yr of age) distinguished on the basis of marked differences in their typical time course of clinical deterioration leading to in-hospital management. Group I patients (n = 8) had rapid clinical deterioration (occurring within 8 h from the onset of respiratory symptoms), whereas in Group II patients (n = 7), clinical deterioration occurred relatively slowly (i.e., exceeding 24 h from the onset of respiratory symptoms). Pharmacologic bronchial sensitivity was evaluated as the log dose of the agonist producing a 20% fall in FEV1 (PD20 X FEV1) and a 35% fall in specific conductance (PD35 X SGaw). Exercise-induced bronchospasm was evaluated in terms of the maximal decrease in FEV1 and SGaw after 6 min of steady-state treadmill exercise at 85% of the age-predicted maximal heart rate. Group I patients had near normal baseline FEV1 and SGaw, whereas in Group II patients, the baseline values of these parameters were significantly reduced (p less than 0.02). Group I was more sensitive to methacholine than was Group II, providing significantly lower mean values of PD20 X FEV1 (p less than 0.003) and PD35 X SGaw (p less than 0.001). On the other hand, the 2 groups were not significantly different with respect to their bronchial sensitivity to either histamine or exercise challenge. Thus, asthmatic children with marked differences in clinical presentation of bronchospasm may be further distinguished on the basis of methacholine sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1984

Development of posterior subcapsular cataracts in asthmatic children.

Posterior subcapsular cataracts (PSCC) are known complications of systemic steroid therapy. Previous studies have not clearly identified the asthmatic children at risk for the development of PSCC. The possible factors associated with systemic steroid administration that may influence the development of PSCC in asthmatic children were evaluated: (1) duration of administered steroids, (2) dose, (3) number of steroid "bursts" in the preceding year, (4) degree of retardation of bone age, and (5) mode of administration (daily or alternate day) of steroids. Of the 40 asthmatic children requiring steroids, seven (17.5%) had PSCC. All of the children with PSCC had been receiving steroids on a daily or alternate-day basis for at least 2 years and all had markedly delayed bone age. Only one child with the concurrent occurrence of these two factors did not develop PSCC. None of the other risk factors considered could distinguish the group of patients with PSCC. It is concluded that asthmatic children receiving steroids for 2 years or longer and having markedly delayed bone age are at a greater risk for the development of PSCC.

Adolescent↗