Biomedical subjects

G Trakada

Publications and source records attributed to G Trakada.

14 recordsLinked to original sources

PubMed2005

IL-6 and its circadian secretion in humans.

Interleukin-6 (IL-6) is a pleiotropic cytokine produced by numerous types of immune and nonimmune cells and is involved in many pathophysiologic mechanisms in humans. Many studies suggest that IL-6 is a putative 'sleep factor' and its circadian secretion correlates with sleep/sleepiness. IL-6 is elevated in disorders of excessive daytime sleepiness such as narcolepsy and obstructive sleep apnea. It correlates positively with body mass index and may be a mediator of sleepiness in obesity. Also the secretion of this cytokine is stimulated by total acute or partial short-term sleep loss reflecting the increased sleepiness experienced by sleep-deprived individuals. Studies that evaluated the 24-hour secretory pattern of IL-6 in healthy young adults suggest that IL-6 is secreted in a biphasic circadian pattern with two nadirs at about 08.00 and 21.00, and two zeniths at about 19.00 and 05.00 h. In contrast, following sleep deprivation or in disorders of sleep disturbance, e.g., insomnia, IL-6 peaks during the day and, based on the level of stress system activity, i.e., cortisol secretion, contributes to either sleepiness and deep sleep (low cortisol) or feelings of tiredness and fatigue and poor sleep (high cortisol). In order to address concerns about the potential impact of differences of IL-6 levels between the beginning and the end of the 24-hour blood-drawing experiment, we proceeded with a cosinor analysis of 'detrended' data in young and old healthy individuals. This new analysis did not affect the biphasic circadian pattern of IL-6 secretion in young adults, while it augmented the flattened circadian pattern in old individuals in whom the difference was greater. Finally, IL-6 appears to be somnogenic in rats and exhibits a diurnal rhythm that follows the sleep/wake cycle in these animals. We conclude that IL-6 is a mediator of sleepiness and its circadian pattern reflects the homeostatic drive for sleep.

Aging↗

PubMed2004

Arterial oxygen tension during sleep in the third trimester of pregnancy.

BACKGROUND: Changes during pregnancy include reduced functional residual capacity (FRC) and residual volume (RV), increased alveolar difference for oxygen and, in the supine position, reduced cardiac output. In conjunction with sleep-related disturbances, these changes could lead to maternal oxygen desaturation during sleep. OBJECTIVES: Because of conflicting data from respiratory sleep studies in pregnancy, we performed complete polysomnography on 21 pregnant women at the 36th week of gestation and again postpartum. We also measured the partial pressure of oxygen in the arterial blood (PaO2) in the supine and sitting positions. METHODS: We tested 21 healthy pregnant women at the 36th week of gestation. Arterial samples were taken in the sitting position. Complete polysomnography was performed in all of the pregnant women. Before the polysomnography arterial samples were taken in the supine and sitting positions and then every 2 h until termination of the study. RESULTS: We did not find any correlation between SaO2/PaO2 levels and apnea, hypopnea or percent of rapid eye movement (REM) sleep. The frequency of apnea and hypopnea was significantly lower during pregnancy (5.81 +/- 2.1 apneas or hypopneas per hour of sleep) than postpartum (12.1 +/- 2.7 apneas or hypopneas per hour of sleep) (p < 0.001), which may be due to the raised level of progesterone. The PaO2 levels in the supine position were significantly lower than in the sitting position at 36 weeks of gestation (p < 0.001). No differences were found between PaO2 levels in the sitting and supine positions postpartum (p < 0.5). CONCLUSIONS: According to our results we conclude that 1) the frequency of apnea and hypopnea in pregnancy was significantly lower than postpartum, and 2) a significant difference in PaO2 levels in the sitting and supine positions was observed at 36 weeks of gestation.

Adult↗

PubMed2004

Marked decrease in sleepiness in patients with sleep apnea by etanercept, a tumor necrosis factor-alpha antagonist.

The proinflammatory cytokines, TNFalpha and IL-6, are elevated in obstructive sleep apnea (OSA) and have been proposed as mediators of excessive daytime sleepiness in humans. We tested the effects of etanercept, a medication that neutralizes TNFalpha and is approved by the FDA for the treatment of rheumatoid arthritis, in eight obese male apneics. These patients participated in a pilot, placebo-controlled, double-blind study during which nighttime polysomnography, multiple sleep latency test, and fasting blood glucose and plasma levels of IL-6, C-reactive protein, insulin, and adiponectin were obtained. There was a significant and marked decrease in sleepiness by etanercept, which increased sleep latency during the multiple sleep latency test by 3.1 +/- 1.0 min (P < 0.05) compared with placebo. Also, the number of apneas/hypopneas per hour was reduced significantly by the drug compared with placebo (52.8 +/- 9.1 vs. 44.3 +/- 10.3; adjusted difference, -8.4 +/- 2.3; P < 0.05). Furthermore, IL-6 levels were significantly decreased after etanercept administration compared with placebo (3.8 +/- 0.9 vs. 1.9 +/- 0.4 pg/ml; adjusted difference, -1.9 +/- 0.5; P < 0.01). However, no differences were observed in etanercept vs. placebo in the levels of fasting blood glucose and plasma C-reactive protein, insulin, and adiponectin. We conclude that neutralizing TNFalpha activity is associated with a significant reduction of objective sleepiness in obese patients with OSA. This effect, which is about 3-fold higher than the reported effects of continuous positive airway pressure on objective sleepiness in patients with OSA (0.9 vs. 3.1 min), suggests that proinflammatory cytokines contribute to the pathogenesis of OSA/sleepiness.

Adiponectin↗

PubMed2003

Normal pregnancy and oxygenation during sleep.

Pregnancy is associated with significant alterations in respiratory function. Changes during pregnancy include reduced functional residual capacity (FRC) and residual volume (RV), increased alveolar-arterial difference for oxygen (A-alphaPO2) and in the supine position, reduced cardiac output. In conjunction with sleep-related apneas or hypopneas, these could lead to maternal oxygen desaturation during sleep. Because of the conflicting data from sleep studies in late pregnancy, we performed complete polysomnography on 11 pregnant women at 36 weeks of gestation and again postpartum. We also measured the PaO2, every 2h. The frequency of apneas and hypopneas was significantly lower during pregnancy compared with that on the postpartum control night. PaO2 levels in the supine position, during sleep, were also significantly lower during pregnancy compared to the postpartum period. No correlation was observed between PaO2 levels and apneas or hypopneas or percent of REM sleep.

Adult↗

PubMed2003

Hematologic and biochemical laboratory parameters before and after a marathon race.

Marathon racing is a strenuous exercise that has a profound effect on many laboratory parameters. Participants in marathon races may require abstinence of exercise and the performance of laboratory assays several days after the event. The aim of this study was to evaluate the possible changes in blood cell count and biochemical parameters observed in participants in a marathon 3 days before and 3 days after and before and immediately after a cardiopulmonary exercise test. Incremental cycle ergometry up to maximal capacity was performed in 7 marathon runners, 3 days before and 3 days after the race. The % peak oxygen consumption (peak %VO(2)) achieved was statistically significantly lower after than before the race ( p = 0.02). No statistically significant differences were observed in cardiac frequency ( p = 0.148) or blood cell count ( p = 0.501). Also, the concentration of sodium, potassium, calcium, magnesium, lactate dehydrogenase (LDH), phosphocreatine kinase (CPK) and glucose, measured before and immediately after the pulmonary exercise test, did not differ significantly ( p < 0.5). A significant percentage of the laboratory results were outside the standard reference rates. According to our data, exercise performance, as expressed by peak %VO(2), continued to be decreased in marathon runners 3 days after the race. The blood cell count and biochemical parameters did not differ significantly but many marathon runners were outside the standard reference rates. Unfortunately, only 7 subjects were available for this study. Further studies with larger samples and with samples obtained at multiple times during and after exercise are needed to clarify the effects of long-distance running.

Blood Cell Count↗

PubMed2003

Can high resolution computed tomography predict lung function in patients with chronic obstructive pulmonary disease?

High-resolution computed tomography (HRCT) is a useful method for quantifying the extent of emphysema. Few reports have mentioned the relationships between HRCT scans and pulmonary function tests in chronic obstructive pulmonary disease (COPD). For diagnosis, COPD requires chronic airflow limitation and emphysema and/or chronic bronchitis. We examined 20 who were previous smokers with middle to moderate COPD. All were normocapnic with mean arterial oxygen pressure (PaO2) 77,52 +/- 16,789 mmHg. Forced spirometry, somatic plethysmography and cardiopulmonary exercise test were performed in each patient. HRCT was performed in both full inspiration and full expiration at three levels through the upper (at the aortic arch), lower (2 cm above the diaphragm), and middle lung (midpoint between upper and lower) levels. During expiration all pulmonary function parameters correlated with the HRCT grade in the middle right and left part of the lungs. The middle right part of the lung during expiration correlated statistically significant with MVV (r = -0.681, p = 0.001), forced vital capacity (FVC) (r = -0.477, p = 0.027), forced expiratory volumein 1 sec (FEV1) (r = -0.632, p = 0.002), resistance (r = 0.674, p = 0.001), residual volume (RV) (r = 0.733, p = 0.001), total lung capacity (TLC) (r = 0.696, p = 0.001), functional residual capacity (FRC) (r = 0.752, p = 0.001) and peak oxygen consumption during exercise (VO2) (r = -0.493, p = 0.023). The middle left part of the lung during expiration correlated statistically significant with MVV (r = -0.673, p = 0.001), FVC (r = -0.493, p = 0.027), FEV1 (r = -0.629, p = 0.003), resistance (r = 0.593,p = 0.005), RV (r = 0.601, p = 0.005), TLC (r = 0.546, p = 0.012), FRC (r = 0.594, p = 0.006) and peak VO2 (r = -0.525, p = 0.015). Forced expiratory volume in 1 sec (FEV1), which is a well-established measure of airflow obstruction, correlated with the HRCT grade (1) in the middle left part of the lung during inspiration (r = -0.468, p = 0.035) and during expiration (r = - 0.629, p = 0.003) (2) in the lower right lung during inspiration (r = -0.567, p = 0.007) and during expiration (r = -0.558, p = 0.008) (3) in the lower left lung during inspiration (r = -0.542, p = 0.011) and during expiration (r = -0.558, p = 0.008) (4) in the upper right lung during expiration (r = -0.469, p = 0.037) (5) in the upper left lung during expiration (r = -0.463, p = 0.035) and (6) in the middle right lung during expiration (r = -0.632, p = 0.002). According to our results HRCT was a valuable tool for evaluating the severity of COPD--especially the middle right and left part of the lungs, during expiration--and correlated well with pulmonary function tests.

Exercise Test↗

PubMed2003

Endothelin-1 levels in the pathophysiology of chronic obstructive pulmonary disease and bronchial asthma.

BACKGROUND: Endothelin-1 (ET-1) has been implicated in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). The ET-1 levels are elevated during exacerbations of asthma and COPD in bronchoalveolar lavage, serum, and sputum and fails with treatment of the exacerbations. Hypoxemia stimulates ET-1 secretion. OBJECTIVE: The aim of this study was to examine the serum ET-1 levels in stable asthmatic and COPD patients. MATERIALS AND METHODS: We examined 48 COPD and 26 asthmatic patients and 34 normal subjects. We collected arterial samples to measure baseline ET-1 levels in all patients and in the control group, during the day. All the patients underwent formal polysomnography (EEG, ECG, airflow, respiratory muscle movement, oximeter) to detect the presence of nocturnal, nonapneic, and oxyhemoglobin desaturation. Twelve of the COPD patients and six of the asthmatic patients were disqualified because of inadequate sleep or sleep apnea syndrome. Nineteen of the COPD patients desaturated below a baseline sleep saturation of 90% for 5 min or more, reaching a nadir saturation of at least 85%. We collected arterial samples to measure ET-1 levels, 5 min after the first period of desaturation in each of the 19 desaturators COPD patients. None of the 20 asthmatic patients exhibited oxyhemoglobin desaturation during sleep. RESULTS: Baseline arterial ET-1 levels during the day were significantly higher in "desaturators" COPD patients (2.08+/-0.28 pg/ml) compared to "non-desaturators" COPD patients (1.38+/-0.16 pg/ml) (P<0.001) and to asthmatics (0.7+/-0.85 pg/ml) (P<0.001). ET-1 Levels in normal subjects were 1.221+/-0.02 pg/ml. In "desaturators" COPD patients ET-1 levels during the night, 5 min after the first oxyhemoglobin desaturation, were significantly higher (4.28+/-1.10 pg/ml) compared to those during the day (2.08+/-0.28 pg/ml) (P<0.001). A significant negative correlation was observed between ET-1 levels and degree of desaturation during the day (P=0.005, r=0.632) and during the night (P<0.001, r=0.930) in "desaturators" COPD patients. CONCLUSION: According to our results: (1) ET-1 levels were significantly higher in "desaturators" COPD patients than in "non-desaturators" COPD and in asthmatics; (2) ET-1 levels were significantly higher during the night than during the day in "desaturators" COPD patients; (3) the degree of desaturation correlated negatively with the ET-1 levels in "desaturators" COPD patients, both during daytime and nighttime. These findings are consistent with the hypothesis that ET-1 is implicated in the pathophysiology of asthma and COPD, especially if nocturnal, nonapneic, oxyhemoglobin desaturation exists.

Asthma↗

PubMed2001

Mechanisms of endothelin-1 elevation in chronic obstructive pulmonary disease patients with nocturnal oxyhemoglobin desaturation.

BACKGROUND: Nonapneic, oxyhemoglobin desaturation associated with sleep has been described in patients with chronic obstructive pulmonary disease (COPD). Hypoxemia stimulates endothelin-1 (ET-1) secretion. Once released, ET-1 can act locally to elicit sustained pulmonary artery vasoconstriction, bronchoconstriction and activation of alveolar macrophages. OBJECTIVE: The aim of this study was to examine a possible correlation between ET-1 levels and nocturnal, nonapneic, oxyhemoglobin desaturation during sleep, in patients with COPD. METHODS: We examined 48 COPD patients with formal polysomnography (EEG, ECG, airflow, respiratory muscle movement, oximeter) to detect the presence of nocturnal, nonapneic, oxyhemoglobin desaturation. Twelve of them were disqualified because of inadequate sleep or sleep apnea syndrome. Nineteen of them desaturated below a baseline sleep saturation of 90% for 5 min or more, reaching a nadir saturation of at least 85%. We collected arterial samples to measure ET-1 levels, after 5 min of the first period of desaturation, in each of the 19 patients. We also collected arterial samples in the morning, before the study, to measure baseline ET-1 levels in all patients. RESULTS: Baseline arterial ET-1 levels during the day were very significantly higher in 'desaturator' COPD patients (2.058 +/- 0.252 pg/ml) compared to 'non-desaturator' COPD patients (1.382 +/- 0.159 pg/ml; p < 0.001). Also in 'desaturator' COPD patients ET-1, levels during the night were significantly higher (4.297 +/- 1.107 pg/ml) compared to those during the day (p < or = 0.001) and a significant negative correlation was observed between ET-1 levels and degree of desaturation (p < 0.0001, r = 0.9305). CONCLUSIONS: According to our study we can conclude that (1) ET-1 levels are significantly higher in 'desaturator' COPD patients both during the day and during the night, and (2) ET-1 levels correlate negatively significant with the degree of the oxyhemoglobin desaturation. These findings are consistent with the hypothesis that ET-1 plays a very important role in the pathophysiological manifestations of COPD patients.

Aged↗

PubMed2001

Arterial endothelin-1 in interstitial lung disease patients with pulmonary hypertension.

The aim of this study was to evaluate the plasma arterial levels of Endothelin-1 (ET-1) and their relationship with hypoxia and pulmonary hypertension (PH) in patients with interstitial lung disease (ILD). Incremental cycle ergometry was performed in all patients up to maximal capacity. ET-1 levels during exercise (2.2 +/- 0.36 pgr/ml) were significantly higher than at rest (1.73 +/- 0.37 pgr/ml) (p < 0.001). ET-1 levels were also significantly correlated with arterial oxygen (PaO2) (r = -0.935, p < 0.001) and mean pulmonary arterial pressure (Ppa) (r = 0.657, p < 0.001). Increased pulmonary and peripheral blood levels of ET-1 have been described in, and postulated to contribute to, the pathophysiology of several lung diseases. In agreement with this, in the current study, the plasma arterial levels of ET-1 were also found to be significantly elevated in patients with various interstitial lung disorders during exercise, especially in those with severe hypoxia and pulmonary hypertension.

Endothelin-1↗

PubMed2000

Arterial and bronchoalveolar lavage fluid endothelin-1 concentration in asthma.

Endothelins are a family of peptide mediators that have a number of biological properties, including the ability to act as bronchoconstrictors and vasoconstrictors of isolated airways and vessels. Endothelin-1 (ET-1) is the more potent peptide compared with the other two peptides of the family. To examine a possible involvement of ET- 1 in the pathogenesis of asthma, we measured arterial ET-1 levels in 11 patients with atopic asthma during attack and during remission, and in 11 healthy control subjects. We also performed fiberoptic bonchoscopy and bronchoalveolar lavage (BAL) to measure ET-1 levels in the 11 asthmatic patients during remission, and in the 11 healthy control subjects. ET-1 concentrations in arterial blood and in BAL were measured by a radioimmunoassay method. Arterial ET-1 levels were very significantly higher in asthma attack (3.67 +/- 0.51 pg ml(-1)) and in asthma remission (2.65 +/- 10.62 pg ml(-1)) compared with those of the healthy controls (1.37 +/- 0.14 pg ml(-1)) (P < 0.001). Arterial ET-1 levels were also very significantly higher during asthma attack compared with those in asthma remission (P < 0.001). BAL ET-1 levels were significantly higher in asthma remission (0.73 +/- 0.53 pmol g(-1)) compared with those of the healthy controls (0.16 +/- 0.02 pmol g(-1)) (P < 0.05). No correlation was observed between arterial and BAL ET-1 levels, PaO2 and peak expiratory flow rate (PEFR). These data are consistent with the hypothesis that ET-1 contributes to the pathophysiology of asthma. However, it is likely that the true importance of this vasoconstrictor peptide will only be revealed by pharmacological studies with specific receptor antagonists.

Adolescent↗

PubMed2000

Chronic obstructive pulmonary disease management among primary healthcare physicians.

The aim of this study was to evaluate the dissemination of chronic obstructive pulmonary disease (COPD) management guidelines among primary healthcare physicians in Greece. One hundred and five of 120 (87.5% response rate) completed a questionnaire about COPD morbidity and management. One in eight patients examined by a primary care physician suffered from COPD. Forty-eight physicians treated their COPD patients according to the pulmonologist's recommendations and 69 according to COPD management guidelines. All the physicians encouraged and supported their COPD patients in stopping smoking, but continuous abstinence was low. The most commonly prescribed drugs were beta 2-agonist inhalers (14.8%), corticosteroid inhalers (13.47%), antibiotics (12.6%) and influenza vaccines (12.6%). The most commonly prescribed antibiotics were cephalosporins (33.72%), macrolides (27.71%) and amoxycillin plus clavulanic acid (25.3%). According to the present study, chronic obstructive pulmonary disease management among primary healthcare physicians was not in total accordance with current guidelines. Better dissemination of chronic obstructive pulmonary disease guidelines among specialists and primary healthcare physicians will hopefully make chronic obstructive pulmonary disease management in outpatients optimal.

Greece↗

PubMed1999

Non-invasive estimation of pulmonary arterial hypertension in chronic obstructive pulmonary disease.

The feasibility and reliability of the combination of several noninvasive methods using a multivariate method of analysis to predict pulmonary artery hypertension (PAH) is evaluated in 20 patients with chronic obstructive pulmonary disease. These methods comprised arterial blood gases (Pao2, Paco2), pulmonary functional parameters (FEV1), echo-Doppler parameters (tricuspid regurgitation jets, acceleration time on pulmonary valve), computed tomography measurements (transhilar distance, hilar thoracic index, and measurement of the descending branch of the right pulmonary artery to the lower lobe). A multiple stepwise regression analysis (including one Doppler parameter, two parameters of arterial blood gases, and one functional parameter) revealed a coefficient of determination (R2) equal to 0.954 for mean pulmonary artery pressure (MPAP) with a standard error of estimate (S.E.E.) of 5.25 mmHg. A stepwise regression analysis including computed tomography and radiographic parameters revealed an R2 equal to 0.970 for PAP with a S.E.E. of 4.26 mmHg. Logistical regression analysis classified correctly 80% of patients with PAH using noninvasive methods such as the diameter of the main pulmonary artery and the diameter of the left pulmonary arterial branch calculated by computed tomography. Not only the presence of PAH but also the level of MPAP can be estimated by the combination of multiple stepwise and logistical regression analyses.

Aged↗

PubMedDate not supplied

Evaluation of arterial endothelin-1 levels, before and during a sleep study, in patients with bronchial asthma and chronic obstructive pulmonary disease.

BACKGROUND: Endothelin (ET)-1 has been implicated in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). The ET-1 levels are elevated during exacerbations of asthma and COPD in bronchoalveolar lavage, serum, and sputum, falling with treatment of the exacerbations. OBJECTIVE: The aim of this study was to examine the ET-1 blood levels in stable asthmatic patients and stable COPD patients during alertness and sleep. MATERIALS AND METHODS: We examined 48 COPD and 20 asthmatic patients. All underwent forced spirometry, measurement of SaO2 and of arterial ET-1 levels and nocturnal polysomnography. ET-1 levels were also determined during nocturnal oxyhaemoglobin desaturation. RESULTS: The daytime SaO2 level of our asthmatic patients was higher than that of our COPD patients (p < 0.001). Daytime SaO2 level of our non-desaturator COPD patients was higher than that measured in desaturator COPD patients. Nightime SaO2 level in our asthmatic patients was higher than that in our desaturator COPD patients (p < 0.001). Daytime ET-1 levels in desaturator COPD patients were higher than those observed in normal individuals, in non-desaturator COPD patients and in asthmatic patients. The COPD desaturator patients had higher levels of ET-1 during nighttime than during daytime (p < 0.001). CONCLUSION: Asthmatic patients did not exhibit desaturation of haemoglobin during the night. ET-1 levels are significantly higher in desaturator COPD patients compared with non-desaturator COPD patients, both during the day and during the night. ET-1 levels in stable COPD patients are significantly higher than in patients with stable asthma. These findings are consistent with the hypothesis that ET-1 is implicated in the pathogenesis of COPD and asthma.

Asthma↗

PubMedDate not supplied

Drug-resistance of Mycobacterium tuberculosis in Patras, Greece.

BACKGROUND: The global distribution of drug resistant tuberculosis reflects the quality of tuberculosis control worldwide and is still a major public health-problem. To our knowledge, no data exists in literature about resistance to anti-tuberculosis drugs in Greece. METHODS: The aim of this study was to determine the prevalence of resistance to the main anti-tuberculosis drugs in newly and previously treated tuberculosis patients, in the region of Patras, in Greece and to evaluate the contribution of foreign-born and human immunodeficiency virus (HIV) positive cases to drug resistance. RESULTS: A total of 207 initial isolates of Mycobacterium tuberculosis were analysed. All clinical specimens submitted for cultural diagnosis were collected before chemotherapy commenced. The age of the patients varied from 16 to 78 years old. Sex distribution was 144 males (69.56%) and 63 females (30.43%). Nineteen patients (9.17%) were recent immigrants in Greece. All the patients were HIV-negative. One hundred-one initial isolates of Mycobacterium tuberculosis (48.79%) were susceptible to all first-line anti-tuberculosis drugs, isoniazid, streptomycin, ethambutol and rifampicin. The prevalence of primary mono- and poly-drug resistance was lower (isoniazid 5.79%, streptomycin 4.34%, ethambutol 1.93%, isoniazid + streptomycin 3.38%, isoniazid + ethambutol 0.9%, isoniazid + streptomycin + ethambutol 1.44%) when compared with the prevalence of secondary (acquired) mono- and poly-drug resistance (isoniazid 8.69%, streptomycin 10.14%, ethambutol 3.86%, isoniazid + streptomycin 3.86%, isoniazid + rifampicin 1.44%, isoniazid + streptomycin + ethambutol 4.83%, isoniazid + streptomycin + rifampicin 1.44%). No primary mono - resistance to rifampicin, or primary multi - drug resistance (defined here as Mycobacterium tuberculosis resistant to at least isoniazid and rifampicin) were observed. CONCLUSIONS: According to our data, overall drug resistance was high. Fortunately, multi-drug resistance tuberculosis was not common but special efforts are needed to monitor the prevalence of drug resistance and to ensure adequate treatment in all the population.

Adolescent↗