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Biomedical subjects

S Kivity

Publications and source records attributed to S Kivity.

100 records · Page 6Linked to original sources
PubMed1984

Bronchodilating effect of cromolyn sodium in asthmatic patients at rest and following exercise.

A total of 27 patients with extrinsic asthma participated in a double-blind trial comparing the effect of nebulized cromolyn sodium and placebo on pulmonary function both at rest and after exercise. At rest, cromolyn sodium improved lung function. Compared to baseline, peak expiratory flow rate (PEFR) increased by 20.5 + 11.8% and 8.8 +/- 16.0% after cromolyn sodium and placebo, respectively. The difference is statistically significant (p less than 0.01). Following drug administration immediately after completing six minutes of free running exercise, PEFR increased by 2.3 +/- 8.2% with cromolyn sodium, whereas a fall of 19.8 +/- 12.5% was observed with placebo. This difference is significant at the p less than 0.01 level. The results show that cromolyn sodium is capable of producing immediate bronchodilatation in asthmatic subjects, both at rest and following induction of bronchoconstriction by exercise. These findings suggest that cromolyn sodium may have mechanisms of action other than stabilizing mast cell degranulation.

Adolescent↗
PubMed1982

The effect of some factors on the inhibitory nervous systems of airway smooth muscle.

To understand better the physiological role of the inhibitory nervous systems (i.e. adrenergic and nonadrenergic) operating in airway smooth muscle, the roles of different physiological conditions were studied using segments of trachea isolated from male guinea pigs (300-400 g BW; Camm-Hartley strain). Laryngeal, cervical and thoracic segments of trachea were used from each animal. Platinum plate electrodes were employed to generate an optimal electrical field stimulation of 40 V, 1.5 msec, 40 PPS of 12 sec duration. Biphasic contractile response was reported as change in the isometric force (g). Adrenergic and nonadrenergic components of airway smooth muscle relaxation were assessed using D,L-propranolol (1 X 10(-6) M), a dose which did not influence the developed isometric force. We investigated the effect of the following experimental conditions on developed active relaxation: (a) different temperatures (29, 37 and 40 degrees C), (b) pH = 7.00, 7.38 and 7.56 (all +/- 0.05), and (c) moderate hypoxia (PO2 = 50 +/- 5 Torr). It was found that: (1) No significant differences were detected in the active relaxation in three regions of guinea pig trachea. In guinea pig trachea nonadrenergic inhibition was responsible for approximately 75-80% of total relaxation; (2) A decrease in temperature to 29 degrees C inhibited (P less than 0.05) and an increase in temperature to 40 degrees C potentiated (P less than 0.01) relaxation in both adrenergic and nonadrenergic components; (3) A low pH of 7.10 +/- 0.05 inhibited (P less than 0.05) and a high pH of 7.56 +/- 0.05 potentiated (P less than 0.05) relaxation as induced by electrical field stimulation; (4) Acute hypoxia, Po2 = 50 +/- 5 Torr, significantly inhibited (P less than 0.01) active relaxation of tracheal preparations. This inhibition, however, was reversible. These data suggest that in the condition of acidosis and hypoxia, such as is present in patients with chronic obstructive airway disease, the alteration of the inhibitory nervous systems of airway smooth muscle (both adrenergic and nonadrenergic) may contribute to the development of airway obstruction.

Animals↗
PubMed1981

Plasma and platelets potentiate a hypoxic vascular response of the isolated lung.

To determine whether plasma and /or platelets play a role in the hypoxic response of pulmonary circulation, we perfused isolated rat lungs with different concentrations of plasma and varying numbers of platelets. As the lungs were perfused with a constant flow (8-13 ml/min), a change in the mean pulmonary artery perfusion pressure (PApP) during acute alveolar hypoxia was a measure of increased tone of the pulmonary circulation. It was found that the presence of plasma in the perfusate (both 20% and 100%) significantly (P less than 0.05) potentiated the PApP response during repeated acute alveolar hypoxia, compared with the response to artificial perfusate without plasma. An isolated rat lung perfused with 6.5% dextran or 3% albumin (both in a physiological salt solution) showed only minimal pressure response during acute alveolar hypoxia. In the second part of the experiment, isolated lungs were perfused with a fresh 100% plasma containing different numbers of platelets. A dose-response-like relationship was observed between the number of platelets in the perfusate and the response of the pulmonary vasculature to acute hypoxia. The highest hypoxic response of the pulmonary vessels, as indicated by the increase in PApP, was shown when the perfusate contained a nearly normal in vivo number of platelets. It can be concluded that both plasma and platelets are important factors that can significantly alter the hypoxic response of the pulmonary vasculature in isolated rat lungs.

Animals↗
PubMed1980

A dose-response-like relationship between minute ventilation and exercise-induced bronchoconstriction in young asthmatic patients.

Seven adolescent patients with bronchial asthma performed bicycle exercise tests on several occasions, within 1 week. After the determination of baseline pulmonary function (using spirometry, maximal expiratory flow-volume curves and body plethysmography), all subjects were exercised on the bicycle ergometer for 10 min. On each occasion a different level of minute ventilation (VE, 1/min) was achieved, because of different work performed. Following each exercise test, the degree of exercise-induced bronchoconstriction was assessed. It was found that the degree of bronchoconstriction, as measured by pulmonary function tests, is function of VE measured during exercise. A dose-response-like relationship, i.e., level of VE vs. bronchoconstrictive response, seems to be an important individual characteristic of the airway reactivity of young patients with bronchial asthma.

Adolescent↗
PubMed1975

Benign focal epilepsy of childhood. A follow-up study of 100 recovered patients.

Benign focal epilepsy of childhood is an entity that includes characteristic clinical and electroencephalographic manifestations. Clinically, it consists of typical brief, hemifacial seizures that tend to become generalized when they occur nocturnally. The EEG findings include slow, diphasic, high-voltage, centro-temporal spikes, often followed by slow waves. Retrospective and prospective studies were carried out on 100 such patients, all of whom recovered before reaching adulthood, with the disappearance of both the clinical manifestations and the EEG findings.

Adolescent↗