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Biomedical subjects

N C Syabbalo

Publications and source records attributed to N C Syabbalo.

16 recordsLinked to original sources
PubMed2000

Prevalence of asthma, allergic rhinitis, and eczema in 13- to 14-year-old children in Kuwait: an ISAAC study. International Study of Asthma and Allergies in Childhood.

OBJECTIVES: To determine the prevalence of asthma and allergic diseases in 13 to 14 years old children in Kuwait. DESIGN: Supervised self-administered written and video questionnaires of the international study of asthma and allergies in childhood (ISAAC). SUBJECTS: Students at third and fourth years from 40 intermediate level schools chosen randomly from across Kuwait. RESULTS: 3,110 students were surveyed. The prevalence rates (95% CI) in the written questionnaire for wheeze ever, current wheeze (within the last 12 months), and physician diagnosis of asthma are 25.9% (24.5 to 27.4), 16.1% (15.8 to 17.4), and 16.8% (15.5 to 18.1) respectively. The prevalence rates (95% CI) for symptoms of allergic rhinitis (AR) ever, current symptoms of allergic rhinitis (AR), and diagnosis of AR are 43.9% (42.2 to 45.6), 30.7% (29.1 to 32.4) and 17.1% (14.8 to 18.4) respectively. The prevalence rates (95% CI) for itchy rash ever, current itchy rash, and diagnosis of eczema are 17.5% (16.2 to 18.8), 12.6% (11.4 to 13.8), and 11.3% (10.2 to 12.4) respectively. The prevalence of wheeze ever, wheeze during the last year, and physician diagnosis of asthma are higher in males compared with females, P < .01. In multiple logistic regression: male gender (OR 1.6, 95% CI, 1.3 to 2.0) and diagnosis of AR (OR 1.7, 95% CI, 1.4 to 2.2) were associated with the physician diagnosis of asthma even after controlling for symptoms of asthma. CONCLUSION: This is the first study on the prevalence of allergic diseases in Kuwait and it shows that children in Kuwait have a moderate prevalence of asthma, AR, and eczema compared with other countries where the ISAAC study is done. The prevalence of asthma is higher in boys compared with girls.

Adolescent↗
PubMed1994

Differential ventilatory control during constant work rate and incremental exercise.

The purpose of this study was to determine whether the tachypneic breathing pattern of constant work rate, heavy exercise (CWE) is unique to CWE or whether it represents the usual pattern of the respiratory control system at high levels of ventilation (VI). We compared breathing pattern in ten healthy subjects (age 20-29 years) during CWE and maximal incremental exercise (MIE) on a bicycle ergometer. Work rate was constant at 76% of maximum work rate in CWE and progressively increased by 25 watts/minute until exhaustion during MIE. Breathing pattern was examined at matched levels of VI equivalent to 80% and about 100% of maximum VI during CWE (97.1 and 121.4 L.min-1, respectively). Exercise duration (mean+standard deviation) was 13 +/- 6 and 12 +/- 1 min during CWE and MIE, respectively (P = NS). Tidal volume (VT) fell by an average of 0.20 L towards the end of CWE, but was maintained relatively high and constant towards the end of MIE. At high, but not lower, matched levels of VI breathing pattern during CWE was significantly more rapid and shallow than that during MIE. The tachypnoea of CWE did not correlate with the progressive rise in VI, oxygen uptake or cardiac frequency during CWE. We conclude that (1) CWE is associated with a tachypneic influence that is absent or less during incremental exercise; this tachypnea is most marked at the end of CWE. (2) The tachypnoea of CWE is not part of a generalized rate accelerating process during CWE. The mechanism(s) underlying the tachypnoea are unclear but it may be related to inspiratory muscle fatigue, pulmonary oedema, and/or altered respiratory mechanics.

Adult↗
PubMed1993

Carotid chemoreceptors and respiratory adaptations to dead space loading during incremental exercise.

Dead space (VD) loading has been shown to cause an increase in tidal volume and a decrease in respiratory frequency at moderate to high levels of ventilation (VI) during exercise (J. Appl. Physiol. 70: 55-62, 1991). This study examined the role of carotid chemoreceptors (CC) in the breathing pattern response to added VD during maximal incremental exercise; we used hyperoxia to silence the CC. Nine healthy subjects exercised on a bicycle ergometer on 4 different days while inspiring air with VD (AVD) and without VD [air control (AC)] and while inspiring 100% O2 with VD (O2VD) and without VD (O2C). Equipment resistance for VD and control studies was identical, and the exercise tests were done in a randomized order. At a matched level of VI equivalent to 75% VI at the end of the AC experiments (102 l/min), the breathing pattern in the AVD and O2VD tests was significantly deeper and slower (P < 0.05) than that in the AC and O2C tests. The difference in tidal volume between AVD and AC tests (delta = 0.26 +/- 0.16 liter) was not significantly different from that between O2VD and O2C tests (delta = 0.23 +/- 0.23 liter). The breathing pattern was the same in the AC and O2C tests. It is concluded that the altered breathing pattern with VD loading is not mediated by the CC.

Adaptation, Physiological↗
PubMed1986

Effects of pulmonary inhalation of water and histamine aerosols on nasal airflow resistance in man.

We investigated the effect of aerosols inhaled into the lungs on nasal airflow resistance (Rnaw) using a constant inflow pressure method with measured airflow. Isotonic saline and water aerosols produced no immediate significant change in Rnaw and forced expired volume in 1 s (FEV1); however, water gradually decreased FEV1 and increased Rnaw, the response being maximal 10-15 min after provocation. Histamine aerosol significantly increased Rnaw in healthy subjects, asthmatics and asthmatics with allergic rhinitis. There was also a corresponding decrease in FEV1. The increase in Rnaw and the decrease in FEV1 were reversed by inhalation of terbutaline (10 mg . ml-1). Similarly, terbutaline in patients with mild asthmatic attacks decreased Rnaw and increased FEV1. Since terbutaline applied locally into the nose is known to increase Rnaw, we conclude that lung provocation can increase nasal Rnaw, presumably via nervous pathways.

Adolescent↗
PubMed1986

Measurement and regulation of nasal airflow resistance in man.

A method for measuring human nasal airflow resistance (Rnaw) is described. Air flows at constant pressure through both nasal cavities via a face mask and out through the mouth. Airflow is inversely related to Rnaw. The method has several advantages over many other methods for measuring Rnaw, in particular allowing aerodynamic separation of nose and lungs, and frequent measurements over long periods without discomfort to or intervention with subjects or patients. We have used this method to obtain standard values of Rnaw in healthy subjects and in patients with asthma and/or rhinitis. Age has a negative correlation with Rnaw but no sexual difference was seen. Cigarette smoking increases Rnaw especially in young adults. Patients with rhinopathy have much higher resistances than healthy subjects, but those with asthma alone do not. Rnaw is sensitive to changes in ventilation and lung volumes; deep inspiration and oral hyperventilation decrease Rnaw, while deep expiration, nasal hyperventilation and breath-holding increase it. Hypoxia and hypercapnia locally applied in the nose increase Rnaw. It is suggested that these changes are predominantly due to changes in control of the nasal vascular bed.

Adolescent↗
PubMedDate not supplied

Effects of exercise on nasal airflow resistance in healthy subjects and in patients with asthma and rhinitis.

We studied the effect of exercise on nasal airflow resistance (Rnaw) and the relationship between exercise-induced asthma (EIA) and Rnaw. Rnaw was obtained by measurement of flow through the nose and mouth (in series) at constant inflow pressure. In seven healthy subjects, there were statistically significant decreases in Rnaw (39.5 +/- 6.3 and 49.0 +/- 8.2%; p less than 0.05) and no change in forced expired volume immediately after exercise on a bicycle ergometer at both 75 W and 100 W, but there was no significant difference between these two resistance changes. At 75 W, Rnaw returned to pre-exercise level at 15-20 min after exercise. At 100 W, Rnaw remained below the pretest value 30 min after exercise. In eleven asthmatics, treadmill running for 1, 2 and 6 min caused significant decreases (p less than 0.05) in Rnaw up to 44.8 +/- 3.3%, reaching levels similar to those of controls after exercise. With 6 min exercise, four of nine patients developed EIA; these subjects had allergic rhinitis as well, and recovery to pretest valued tended to be quicker than in those without EIA. In healthy subjects at both ergometer workloads, there was a rebound increase in Rnaw in 40-50% of the subjects appearing 20-30 min after exercise. In the patients, there was a rebound increase in Rnaw in about 60% of the subjects 5-10 min after exercise. Both for healthy subjects and patients, the rebound increase in Rnaw was smaller at the higher workloads.

Adolescent↗