Assessing the ideal microwave duration for disinfection of sinus irrigation bottles-A quantitative study.

OBJECTIVES: Saline irrigation of the nasal cavity and paranasal sinuses has a recognised role in the management of chronic rhinosinusitis. However, bacterial recontamination of irrigation bottles through backflow from the sinonasal cavity is a concern in recurrent sinus cavity infections. While patients are encouraged to clean the irrigation bottles regularly, there remains significant concern that the use of contaminated bottles may perpetuate chronic rhinosinusitis. This study assesses the optimal microwave duration to achieve decontamination for each irrigation bottle component part (reservoir, tube and nozzle) using a standard, commercially available microwave. In addition, the irrigation fluid was also tested for contamination after each microwave cycle. STUDY DESIGN: Laboratory-based experimental study. PARTICIPANTS: No patients were involved in this study. MAIN OUTCOME MEASURES: The percentage in vitro decontamination of the bottles' components was determined following 30, 60, 90, 120, 150 seconds of microwave cycles. RESULTS: Complete decontamination of the bottles was not achieved at any of the tested microwave cycles. Levels of decontamination differed for the different bottle components, and the greatest degree of decontamination for all bottle components occurred at 90 seconds. Although higher levels of decontamination were observed at microwave durations exceeding 90 seconds, this was at the expense of thermal degradation and deformation of the reservoir plastic component of the irrigation bottle. Similarly, lowest contamination of irrigation fluid was observed at 120 seconds. CONCLUSIONS: This study highlights the importance of establishing precise decontamination procedures and recommends a microwave cycle of 90 seconds for optimal decontamination.

Molecular epidemiology of rhinoviruses in Cyprus over three consecutive seasons.

Human rhinoviruses (HRVs) are widespread respiratory pathogens and a major cause of acute respiratory tract infections. The aim of this study was to investigate the molecular epidemiology of rhinovirus infections in children in Cyprus over three consecutive winter seasons. From a total of 116 rhinovirus-positive samples, 68 were sequenced in the 5'-UTR and VP4/VP2 regions. Thirty-six (52.9%) samples were identified as HRV-A and 27 (39.7%) as HRV-C, with only five (7.4%) samples belonging to the HRV-B species. Of these, a total of 46 different genotypes were identified. In the VP2/VP4 phylogenetic tree all strains clustered in three different well-defined clades, whereas the 5'-UTR tree exhibited clades with a mixed clustering of HRV-A and HRV-C strains reflecting the evolutionary history of recombination between HRV-A and HRV-C that has been observed previously. In summary, a high intra- and inter-season diversity of HRV types was observed. Despite its geographical isolation the frequency of HRV species in Cyprus is comparable to that reported in other regions of the world supporting the concept of an unrestricted global circulation. This study assesses, for the first time, the epidemiology of rhinovirus infections in Cypriot children and will be helpful to clinicians and researchers interested in the treatment and control of viral respiratory tract infections.

Assessing the use of minimally invasive self-sampling at home for long-term monitoring of the microbiota within UK families.

Monitoring the presence of commensal and pathogenic respiratory microorganisms is of critical global importance. However, community-based surveillance is difficult because nasopharyngeal swabs are uncomfortable and painful for a wide age range of participants. We designed a methodology for minimally invasive self-sampling at home and assessed its use for longitudinal monitoring of the oral, nasal and hand microbiota of adults and children within families. Healthy families with two adults and up to three children, living in and near Liverpool, United Kingdom, self-collected saliva, nasal lining fluid using synthetic absorptive matrices and hand swabs at home every two weeks for six months. Questionnaires were used to collect demographic and epidemiological data and assess feasibility and acceptability. Participants were invited to take part in an exit interview. Thirty-three families completed the study. Sampling using our approach was acceptable to 25/33 (76%) families, as sampling was fast (76%), easy (76%) and painless (60%). Saliva and hand sampling was acceptable to all participants of any age, whereas nasal sampling was accepted mostly by adults and children older than 5 years. Multi-niche self-sampling at home can be used by adults and children for longitudinal surveillance of respiratory microorganisms, providing key data for design of future studies.

Educational intervention on water intake improves hydration status and enhances exercise performance in athletic youth.

We aimed to evaluate whether an intervention program emphasizing in increased fluid intake can improve exercise performance in children exercising in the heat. Ninety-two young athletes participated in the study (age: 13.8 ± 0.4 years, weight: 54.9 ± 1.5 kg). Thirty-one (boys: 13, girls: 18) children served as the control group (CON) and 61 (boys: 30, girls: 31) as the intervention (INT). Volunteers had free access to fluids. Hydration was assessed on the basis of first morning urine. A series of field tests were used to evaluate exercise performance. All tests occurred outdoors in the morning (mean ambient temperature=28°C). After baseline testing, INT attended a lecture on hydration, and urine color charts were mounted in all bathrooms. Additionally, water accessibility was facilitated in training, dining and resting areas. Hydration status was improved significantly in the INT [USG: pre=1.031 ± 0.09, post=1.023 ± 0.012, P<0.05; urine osmolality (mOsm/kg water): pre=941 ± 30, post=782 ± 34, P<0.05], while no statistically significant changes were found in the CON [USG: pre=1.033 ± 0.011, post=1.032 ± 0.013, P>0.05; urine osmolality (mOsm/kg water) 970 ± 38 vs 961 ± 38, P>0.05]. Performance in an endurance run was improved significantly only in INT (time for 600 m: pre=189 ± 5 s, post=167 ± 4 s, P<0.05). Improving hydration status by ad libitum consumption of water can enhance performance in young children exercising in the heat.

Equivalency testing of TTC Tergitol 7 agar (ISO 9308-1:2000) with five culture media for the detection of E. coli in water samples in Greece.

In this study ten laboratories in Greece compared the performance of reference method TTC Tergitol 7 Agar (with the additional test of beta-glucuronidase production) with five alternative methods, to detect E. coli in water, in line with European Water Directive recommendations. The samples were prepared by spiking drinking water with sewage effluent following a standard protocol. Chlorinated and non-chlorinated samples were used. The statistical analysis was based on the mean relative difference of confirmed counts and was performed in line with ISO 17994. The results showed that in total, three of the alternative methods (Chromocult Coliform agar, Membrane Lauryl Sulfate agar and Trypton Bilex-glucuronidase medium) were not different from TTC Tergitol 7 agar (TTC Tergitol 7 agar vs Chromocult Coliform agar, 294 samples, mean RD% 5.55; vs MLSA, 302 samples, mean RD% 1; vs TBX, 297 samples, mean RD% -2.78). The other two alternative methods (Membrane Faecal coliform medium and Colilert 18/ Quantitray) gave significantly higher counts than TTC Tergitol 7 agar (TTC Tergitol 7 agar vs MFc, 303 samples, mean RD% 8.81; vs Colilert-18/Quantitray, 76 samples, mean RD% 18.91). In other words, the alternative methods generated performance that was as reliable as, or even better than, the reference method. This study will help laboratories in Greece overcome culture and counting problems deriving from the EU reference method for E. coli counts in water samples.

Protective effect of PCV vaccine against experimental pneumococcal challenge in adults is primarily mediated by controlling colonisation density.

Widespread use of Pneumococcal Conjugate Vaccines (PCV) has reduced vaccine-type nasopharyngeal colonisation and invasive pneumococcal disease. In a double-blind, randomised controlled trial using the Experimental Human Pneumococcal Challenge (EHPC) model, PCV-13 (Prevenar-13) conferred 78% protection against colonisation acquisition and reduced bacterial intensity (AUC) as measured by classical culture. We used a multiplex qPCR assay targeting lytA and pneumococcal serotype 6A/B cpsA genes to re-assess the colonisation status of the same volunteers. Increase in detection of low-density colonisation resulted in reduced PCV efficacy against colonisation acquisition (29%), compared to classical culture (83%). For experimentally colonised volunteers, PCV had a pronounced effect on decreasing colonisation density. These results obtained in adults suggest that the success of PCV vaccination could primarily be mediated by the control of colonisation density. Studies assessing the impact of pneumococcal vaccines should allow for density measurements in their design.

Substantial increase in cadaveric organ transplantation in Greece for the period 2001-2005.

The Hellenic Transplant Organization (HTO), a nonprofit organization sector of the Greek Ministry of Health, was officially established in 1999. Since March 2001, HTO has been responsible for donation and transplantation processes in Greece and organ sharing between Greece and other European countries. The organization's main tasks are: donor referral, charting, donor assessment, organ evaluation, organ allocation and transplantation. Today, the results show increased success rates to previously believed unthinkable levels. Precisely, the percentage of referred versus used cadaveric donors increased by 468% and 134%, respectively. Cadaveric kidney transplantation has also shown remarkable progress with a 126% increase during the same period. Similarly, liver transplantation showed a threefold rise (89%) during the same time. Unfortunately, heart and lung transplantations remain low, thus preventing statistical conclusions to be drawn. Although Greece in previous years had the lowest donor and transplantation rates per million population, its position compared with other European countries is expected to rise significantly this year. Undoubtedly, the numbers and percentages compared to previous years are due to the radical changes implemented by the HTO, by introducing transplant coordination principles and procurement management, which were concepts not previously established in Greece. However, there are still major obstacles, such as intensivists' refusal to disconnect, inaccessible geographical locations, few transplant centers, and society's suspicion of organ donation concept, that still need attention. Nevertheless, the first step has been taken and other European countries standards will hopefully be attained soon.

Validity of the Greek Eating Disorder Examination Questionnaire 6.0 (EDE-Q-6.0) among Greek adolescents.

The aim of this study is to examine the validity of the Greek version of the Eating Disorder Examination Questionnaire 6.0 (EDE-Q-6.0) in a sample of adolescent pupils. EDE-Q is a self- report instrument that assesses attitudes and behaviors related to Eating Disorders (EDs). A two-stage identification protocol has been applied to the 16 schools that agreed to participate in the present study. Initially, 2058 adolescents, in class under the supervision of one research assistant and one teacher, completed a Questionnaire on socio-demographic data, the Greek EDE-Q-6.0 and the Greek Eating Attitudes Test (EAT-26) while their weight and height were measured. Six-hundred and twenty six participants, who had scores on EAT-26≥20 and/or were underweight or overweight, were considered as "possible-cases" while the remaining 1432 pupils of the sample were thought as "non-possible cases". At the second stage, parents of 66 of the participants identified as possible-cases as well as parents of 72 participants from 358 controls randomly selected from the sample of "non-possible cases" agreed that their children would be examined by means of Best Estimate Diagnostic Procedure. Participants meeting DSM-IV-TR Eating Disorders criteria were identified. Receiver Operating Characteristics (ROC) analysis was applied to reveal EDE-Q's criterion validity. The kappa statistic test was used as measure of agreement between categorical variables at EDE-Q and at interview (the presence of objective binge eating episode, of self-induced vomiting, the use of laxatives and of excessive exercise). The Discriminant and Convergent validity were assessed using the non-parametric Mann-Whitney U test and by means of the Spearman's correlation coefficient, respectively. Nineteen cases of EDs were identified [one case of Anorexia Nervosa (AN), 13 cases of Eating Disorder Not Otherwise Specified (EDNOS), 5 cases of Binge Eating Disorder (BED)]. At the cut off point of 2.6125 on the EDE-Q's global scale the instrument screens with a sensitivity (Se) of 89.5% and a specificity (Sp) of 73.1%, a Positive Predictive Value (PPV) of 34.7% and a Negative Predictive Value (NPV) of 97.8% The same analyses for both sexes revealed a cut-off point of 2.612 for females and of 3.125 for males on the global EDE-Q-6.0 score (Se=84.62%, Sp=73.33% for females and Se=83.33%, Sp= 84.09% for males), yielding a PPV and a NPV of 35.5% and of 96.5% for females and 41.7% and 97.4% for males, respectively. A very low agreement level, between EDE-Q and interview, was observed regarding the presence of objective bulimic episodes (OBEs) [k=0.191 (SE=0.057)] and the unhealthy weight control behaviors [k=0.295 (SE=0.073)]. Positive correlations were found between EAT-26 and EDE-Q-6.0 for both global scale and subscales (rho=0.50-0.57). The results suggest that EDE-Q-6.0, when using its global score, appears to be a proper screening tool for assessing the core psychopathology of eating disorders in community samples in two-stage screening studies since it distinguishes very well the cases from the non-cases. However, the assessment of the presence and frequency of pathological behaviours which characterize EDs appears to be problematic since adolescents, especially the younger ones, misunderstood terms like large amount of food and loss of control or misinterpret the motivation for excessive exercise. Therefore, marked discrepancies were observed between pathological behaviors self-reported at questionnaire and those detected at interview. We may assume that giving participants more information regarding the definition of these concepts may increase the accuracy with which the participants report these behaviors.

Seasonal variation of gastrointestinal nematodes of sheep in the region of Joannina, Greece.

Parasitological and growth studies on two groups of naturally infected sheep, with or without anthelmintic treatment, from the age of 3 months to 2 years were carried out in the region of Joannina, Greece. A split-plot design was used so that each group, consisting of seven pure-bred Boutsiko and seven cross-bred Boutsiko with Karamaniko (F1) lambs, grazed separate parasitologically equivalent pasture plots. Faecal egg counts, pasture larval counts, plasma pepsinogen levels and live weight were recorded monthly. Infective larvae on each pasture plot increased during autumn and winter. Mean faecal egg counts for strongyle-type eggs were higher in the non-treated than the treated group and in the cross than the pure-bred sheep. Mean plasma pepsinogen levels were higher during autumn of the second year of the study. The results of the study suggest that the factors affecting the epidemiology of gastrointestinal nematodes of naturally infected sheep during grazing in the region of Joannina include anthelmintic treatment, host genotype and season, while the effectiveness of anthelmintic treatment in this study, as applied in the area, was questionable.

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.

Intra-renal localization of b2-microglobulin (b2-m) in renal transplant material. An immunohistochemical study.

The distribution of b2-m immunoreactivity in biopsy material (paraffin sections) of 34 patients with renal transplantation was examined. b2-m was present along the glomerular capillary walls and in cytoplasm of the epithelial cells of convoluted tubules and mainly towards their basement membranes in 15 out of 17 with acute rejection, in 5 out of 8 with chronic rejection and only one case of normal donor. The more frequent detection and the more intense staining of b2-m in acute kidney rejection are discussed.

Radiostrontium transfer to sheep's milk as a result of soil ingestion.

Soil ingestion as a source of radiostrontium contamination of ruminant milk products was studied by measuring the transfer coefficient to ovine milk. This is a follow-up report from a previous experiment (Assimakopoulos et al., 1993), which investigated radiocaesium transfer to sheep's milk as a result of soil ingestion. Milk samples from three lactating ewes, housed in individual metabolism cages, were used. Fifty grams per day of heavily contaminated sandy topsoil, collected in the Chernobyl area, were administered orally to the animals for a period of 1 week. The daily intake of 90Sr was 78 Bq day-1. During this contamination period, daily milk production and excreta output were measured. Excreta and milk was collected for an additional 7-day decontamination period, while they were fed on uncontaminated feed. The transfer coefficient was obtained through a best fit (minimum chi 2) of the data to predictions of a linear compartment model. The value obtained was fm = 0.041 +/- 0.016 d kg-1 for radiostrontium transport to milk. This result suggests that soil ingestion can be a major source of radiostrontium contamination in sheep and other free-grazing ruminants.

Radiocaesium transfer to sheep's milk as a result of soil ingestion.

Soil ingestion as a source of radiocaesium contamination to ruminants was studied by measuring the transfer coefficient to sheep milk. Eight lactating ewes, housed in individual metabolism cages, were used. Fifty grams per day of heavily contaminated sandy topsoil, collected in 1990 from the Chernobyl area, were administered orally to the animals for a period of 1 week. The daily dose intake in 137Cs was 1835 Bq day-1. During this contamination period, daily milk production and excreta output were measured. The ewes were monitored for an additional 7 day decontamination period, while they fed on uncontaminated feed. Transfer coefficients were obtained through a best fit (minimum chi 2) of the data to predictions of a linear compartment model. The values obtained were fm = (2.6 +/- 0.7) x 10(-2) and f mu = (5 +/- 2) x 10(-2) days kg-1 for radiocaesium transport to milk and urine, respectively. These results suggest that soil ingestion can be a major source of radiocontamination for sheep and other free-grazing ruminants. Comparison of our results with soil-to-milk transfer coefficient values derived in two recent independent experiments suggests that there might be a strong dependence of radiocaesium availability on soil composition.

Effects of melatonin and plane of nutrition on mammary development in prepubertal Boutsiko mountain breed ewe lambs.

The effects of melatonin (implants, M or no implants, C) and plane of nutrition (high, H or low, L) on mammary development and growth hormone (GH) concentrations were investigated in prepubertal Boutsiko mountain breed ewe lambs. Eighty female lambs were assigned to each of 4 treatments: ad libitum feeding control (HC), HM, LC and LM. The rearing treatments started and ended at mean ages of 63 and 160 d, respectively. Feed restriction resulted in a mean daily gain of 70.6% of the ad libitum-fed lambs during the experimental period. Melatonin (18 mg Regulin) was administered at 68 d of age (January 10) and replaced on March 1. Blood samples were collected from 10 lambs in each treatment group at the end of the experiment for GH measurements. At a mean age of 160 d, seven lambs from each treatment group were slaughtered and the udder was removed. One udder half was trimmed and the parenchyma and fat pad portions were kept for determination of deoxyribonucleic acid (DNA) content. Melatonin did not influence mammary development parameters, while the mass of parenchyma tended to be greater in lambs on low than high nutrition planes (P<0.10). Mean mammary parenchymal weight and DNA content were 25.1 and 29.2 g and 52.5 and 58.2 mg in high and low nutrition lambs, respectively. Mean plasma GH concentrations were not affected by melatonin treatment and were higher in low than high nutrition lambs (P<0.01). There were no correlations between mean plasma GH concentrations and parenchymal DNA content, or between mean daily weight gain and parenchyma (g), in contrast to those found in a previous experiment with lambs of the same breed but greater age at slaughter. The results suggest that a period of accelerated mammary development occurs later than 140 d of age in Boutsiko mountain breed ewe lambs.

Effect of monensin and progesterone priming on ram-induced reproductive performance of boutsiko mountain breed ewes.

The effects of monensin and progesterone priming on reproductive performance (estrous response, lambing rate and prolificacy) of grazing Boutsiko mountain breed adult and 18-mo.-old ewes at the end of seasonal anestrus were investigated. In Experiment 1 the feed supplement with or without monensin was offered for 21 d after introduction of vasectomized rams (Day 0). Progesterone was administered to the ewes in the respective groups as a single injection at Day -3. Ewes of both age groups were assigned randomly to 1 of 4 treatments: C, C+P, C+M and C+M+P. In Experiment 2 the supplement C or M was offered from Day -26 to Day 21. The treatments consisted of C, C+P and C+M+P. Blood samples were taken 50 h after ram introduction for determination of plasma concentrations of P and insulin-like growth factor-I (IGF-I). There was a greater increase in estrous response at Days 17 to 19 and at Days 0 to 19 when supplementation was offered before rather than after ram introduction in both age groups. In the adult group ewes synchronization of estrus at Days 17 to 19 was significantly increased by administration of monensin (P<0.05) and progesterone (P<0.01) compared with the control group in the first but not the second experiment. The incidence of estrus at Days 17 to 19 or at Days 0 to 19 was highest in the adult groups treated with monensin and progesterone in both experiments. In 18-mo.-old ewes progesterone was effective in synchronizing estrus only in Experiment 2. Mean plasma IGF-I concentrations were increased by monensin treatment (P<0.05) in adult ewes that were at the periovulatory stage at blood sampling time. Correlation coefficients between IGF-I and progesterone concentrations in monensin plus progesterone group adults were -0.715 (P<0.02) and -0.516 (P<0.01), respectively across all treatments. The results suggest that monensin and progesterone priming improved reproductive performance, and the monensin-induced increase in plasma IGF-I levels at the periovulatory stage may be causally related to the ability of ovulatory follicles to develop into functional corpora lutea (CL).

The effect of dietary protein levels before turnout on subsequent faecal nematode egg output of grazing sheep in the Joannina region of Greece.

The effect of dietary protein levels before turnout on the subsequent faecal egg output of gastrointestinal nematodes was examined in two genotypes of grazing sheep, with or without anthelmintic treatment. Lambs were given a low protein (LP) or a high protein (HP) diet for three months (December to March) until grazing started. Half of the animals in each diet group were given anthelmintic treatment (AT) in March and June. The four groups (LP-AT, LP-NT, HP-AT and HP-NT) each consisted of pure-bred Butsiko and cross-bred Butsiko/Karamaniko lambs and grazed separate plots that were initially parasitologically and nutritionally similar. Faecal egg counts were recorded monthly until the experiment ended in July. Mean faecal counts for strongyle-type eggs were higher in the LP-NT group than all the other groups and higher in the LP than the HP groups indicating that faecal egg counts during grazing were influenced by levels of dietary protein before turnout. This effect was intensified in the absence of anthelmintic treatment. No genotype differences were detected.

Ratios of transfer coefficients for radiocesium transport in ruminants.

A corollary of the multiple-compartment model for the transport of trace elements through animals was tested for cows, goats, and sheep. According to this corollary, for a given body "compartment" k of the animal (soft tissue, lung, liver, etc.), the ratio a(k) = f(k)/f(blood) of the transfer coefficients f, should exhibit similar values for physiologically similar animals. In order to verify this prediction, two experiments were performed at the Agricultural Research Station of Ioannina and at the facilities of Ria Pripyat in Pripyat, Ukraine. Eight animals in the first experiment and eighteen in the second were housed in individual pens and were artificially contaminated with a constant daily dose of radiocesium until equilibrium was reached. The animals were then sacrificed and transfer coefficients f(k) to twelve body "compartments" k were measured. These data were used to calculate the ratios a(k). The results were in accordance with predictions of the model and average values of a(k) were extracted for ruminants. It is concluded that these values may be employed for the prediction of animal contamination in any body compartment through the measurement of blood samples.

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.