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Original papers

Deletion allele of the ACE gene is not a risk factor for asthma predisposition

Isa Abdi Rad1*, Morteza Bagheri2, Mohammad Hosein Rahimi-Rad3
Deletion allele of the ACE gene is not a risk factor for asthma predisposition

ABSTRACT

Background: Angiotensin-converting enzyme (ACE) has an important role in inactivation of bradykinin and tachykinins which known as powerful bronchoconstrictors. It has been demonstrated that an insertion (I)/deletion (D) genetic variations within the ACE gene greatly influence the plasma level of ACE. Objective: The aim of the present study was to determine the frequencies of ACE D and I alleles and ACE DD, DI and II genotypes in asthmatic patients and controls with Iranian Azeri-Turkish origin and to compare the frequency of the ACE genotypes between asthmatic patients and controls. Methods: We genotyped 212 healthy controls including 73 males and 138 females, as well as 62 patients with asthma, including 28 males and 34 females by PCR. Results: Of the 212 healthy controls: 1) the prevalence of DD, DI, and II genotypes were 83(39.151), 92(43.396) and 37(17.453), respectively. 2) the frequency (%) was 257(60.9) for D allele and 165(39.1) for I allele. 3) D and I allele frequencies were 0.61 and 0.39 respectively. Of the 62 patients with asthma: 1) the prevalence of DD, DI, and II genotypes were 17(27.42), 31(50) and 14(22.58), respectively. 2) the frequency (%) was 65(52.42) for D allele and 59(47.58) for I allele. 3) D and I allele frequencies were 0.52 and 0.48 respectively. Statistical analysis showed that studied groups (female + male patients group and female + male controls group) were in Hardy-Weinberg equilibrium. Our findings imply that I/D ratio was 0.61/0.39 in all controls and 0.6/0.4 in male or female controls. Significant differences were not found in the ACE genotype or allele frequencies between studied groups regarding all cases versus all controls, female cases versus female controls, male cases versus male controls. Conclusion: We have concluded that deletion allele of the ACE gene is not a risk factor for asthma predisposition.

Keywords: ACE, Asthma, Iranian Azeri-Turkish

Reproducibility of cardiac monitoring in men using impedance cardiography during Müeller maneuver

Adrian Aron1, 3, Donald Zedalis2, William G. Herbert1
Reproducibility of cardiac monitoring in men using impedance cardiography during Müeller maneuver

ABSTRACT

Obstructive sleep apnea hypopnea syndrome (OSAHS) is a form of sleep-disordered breathing highlighted by recurrent episodes of upper airway collapse during sleep. OSAHS contributes to an increased risk of cardiac arrhythmias, cardiovascular disease, and altered immune function. Measuring

cardiac function in OSAHS patients can provide information that can help delineate clinical treatment efficacy. Cardiac function has been widely tested using electrical bioimpedance. Aim: The aim of this study was to determine the reproducibility of cardiac functional parameters in subjects performing

Müeller maneuver. Methods: Fifteen apparently healthy males were tested on three different days in a protocol requiring their performance of forced and sustained inspiratory efforts against a closed epiglottis (Müeller maneuver-MM). On each day, the protocol included performance of two simulated apneas of 30 seconds, with at least 3 minutes of normal breathing in between. Results: Changes from a normal breathing baseline for cardiac output, heart rate and stroke volume were comparable during both MM in all three days. The coefficient of variation was similar on all three trials. Conclusions: This new contemporary bioimpedance cardiography device provided reliable measures of dynamic cardiac responses during a simulated apnea event.

Keywords: obstructive sleep apnea, Müeller maneuver, bioimpedance cardiograph

Body position and breathing abnormalities during sleep: a systematic study

Angelica Tiotiu1, Olivier Mairesse2, Guy Hoffmann3, Doina Todea4, André Noseda5
Body position and breathing abnormalities during sleep: a systematic study

ABSTRACT

Background: Until now, studies about body position and nocturnal breathing abnormalities have been restricted to comparing supine versus lateral positions. Objectives: In this retrospective study, we systematically evaluated the effect of body position on nocturnal breathing in 105 patients with a sleep apnea hypopnea syndrome (SAHS). Methods: All the patients had an apnea hypopnea index > 10/h, as judged from polysomnography performed in the sleep laboratory. A thoracic sensor allowed to detect nine distinct body positions: supine (S), supine right (SR), right (R), prone right (PR), prone (P), prone left (PL), left (L), supine left (SL) and sitting upward (UP). Respiratory variables (number of obstructive, central and mixed apneas, of hypopneas and of desaturations, all expressed as an index per hour of total sleep time) were evaluated versus the body positions, using the non-parametric Kruskal-Wallis H method. Pairwise comparisons were performed using Mann-Whitney U tests. Results: Most of the total sleep time (45%) was spent supine. A significant effect of body position was found for all the respiratory variables. Breathing was better in the intermediate SR and SL positions than S, and also better in PR and PL positions than, respectively, R and L. All the respiratory variables gradually improved when gradualling moving from the S to the P position. Conclusions: A nine position sensor, able to define intermediate positions in addition to the basic cardinal positions, is useful in the sleep laboratory. Using such a sensor, we found in SAHS patients that nocturnal breathing improves as a continuum from the S to the P position.

Keywords: body position, sleep apnea hypopnea syndrome, polysomnography