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Biomedical subjects

A Rossi

Publications and source records attributed to A Rossi.

At least 91 records · Page 5Linked to original sources

The human Y chromosome's azoospermia factor b (AZFb) region: sequence, structure, and deletion analysis in infertile men.

Microdeletions of the Y chromosome long arm are the most common mutations in infertile males, where they involve one or more "azoospermia factors" (AZFa, b, and c). Understanding of the AZF structure and gene content and mapping of the deletion breakpoints in infertile men are still incomplete. We have assembled a complete 4.3 Mb map of AZFb and surrounding regions by means of 38 BAC clones. The proximal part of AZFb consists of large repeated sequences organised in palindromes, but most of it is single copy sequence. A number of known and novel genes and gene families map in this interval, and most of them are testis specific or have testis specific transcripts. STS mapping allowed us to identify four severely infertile subjects with a deletion in AZFb with similar breakpoints, therefore suggesting a common deletion mechanism. This deletion includes at least five single copy genes and two duplicated genes, but does not remove the historical AZFb candidate gene RBMY1. These data suggest that other genes in AZFb may have important roles in spermatogenesis. We had no evidence for homologous recombination between large repeats as a possible deletion mechanism, as shown for AZFa and AZFc. However, identical sequences in AZFb and AZFc exist, and this finding could explain deletions found in these regions.

Chromosome Breakage↗

Psychological profile of dysfunctional dysphonia.

A high degree of emotional maladjustment can be detected in dysfunctional dysphonia. In these patients, it is not rare to observe an immediate resolution of the phoniatric disorder, but it is equally as common to identify a significant rate of recurrence (> 10%) in the short and long term. This phenomenon may be due to poor adaptive ability in the presence of mood disorders. Aims of this study were: a. selection of a suitable instrument to identify "minor" and "major" symptoms of psychiatric nature in dysphonic subjects; b. evaluation of profile of mood disorders in dysfunctional dysphonic adults. Hopkins Symptom Check List 90 was chosen. This is a scale of self-evaluation, adapted in Italian, complete (9 dimensions) and easy to use. It is employed to evaluate the following dimensions: somatization, obsessive compulsive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid ideation, psychoticism, sleep disorders. Three groups were studied: group 1:40 patients (36 female, 4 male; aged 18-62 years, mean 42) with dysfunctional dysphonia; group 2: 20 patients (18 female, 2 male; aged 19-61 years, mean 43) with ENT disorders; group 3: 20 subjects (18 female, 2 male; aged 18-62 years, mean 42.2) as controls. In the statistical analysis, a one-way variance between the three groups and a post-hoc analysis using Schiffé test (level of significance 0.05) were carried out. Results showed significant differences between group 1 and groups 2 and 3 as far as concerns anxiety, phobia, obsessive-compulsive, interpersonal sensitivity and somatization variables. A significant difference was found only between groups 1 and 3 as far as concerns the variables: sleep disorders, depression and paranoid ideation. No significant difference emerged between the groups regarding psychoticism and anger/hostility dimensions. The present study identified a definite profile of minor personality disorders, of an anxious nature, with evidence of somatization, interpersonal sensitivity and obsessive-compulsive type traits, significantly prevailing in dysfunctional dysphonic subjects. Symptom Check List-90 has, therefore, proven to be an adequate instrument in the more complete definition of subjects affected by dysfunctional dysphonia aiming at referral to an integrated protocol which focuses on phoniatric treatment using an approach which acts upon the behavioural aspects of communication.

Adolescent↗

Long-term evaluation of esophageal function in patients treated at birth for esophageal atresia.

Dysphagia, gastroesophageal reflux (GER) and esophageal metaplasia are reported with various incidence in the long term follow-up of patients treated at birth for esophageal atresia (EA). To evaluate the long term outcomes 26 patients treated at birth for EA with Tracheo Esophageal Fistula (TEF) were examined 8-28 (mean 15.8) years later by clinical evaluation, including barium meal, fiberoptic upper GI endoscopy, 24 hour ambulatory two-channel pH-monitoring and stationary esophageal manometry. 50% of patients complained of dysphagia. Mild esophagitis was found in 20% of patients but GER was detected in only 16.7% of the cases. By morphological X-ray, esophageal anomalies were detected in 31% of cases without significant functional relevance. Hundred percent of patients had a disorganized peristaltic esophageal activity and a low amplitude of the esophageal contractions was observed in 58% of them. In our series, esophageal dismotilty seems to be the main consequence of EA without any relevant disturbance of normal nutritional habit.

Adolescent↗

Asymptomatic cores and paracrystalline mitochondrial inclusions in CADASIL.

Three siblings with genetically assessed cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) with core-like lesions and mitochondrial abnormalities in muscles are described. Involvement of the Ryanodine receptor 1 gene was excluded. In the current cases, the relation between molecular genetic lesion and muscle fiber abnormalities remains to be determined, but the Notch3 gene may influence mitochondrial metabolism.

Biopsy↗

PANSS factors and scores in schizophrenic and bipolar disorders during an index acute episode: a further analysis of the cognitive component.

To investigate the factor structure of psychotic symptoms, we compared the clinical characteristics of manic patients with those of schizophrenic patients evaluated with positive and negative syndrome scale (PANSS). The clinical symptoms of 148 bipolar patients and 86 schizophrenic patients hospitalized for an index psychotic episode were assessed. Schizophrenic patients showed more positive and cognitive symptoms than bipolars. The factor analysis of the two PANSS scores showed a three-factor solution with 'positive', 'negative' and 'mixed' depressive-activated factors for bipolars and 'positive', 'negative' and 'depressive' factors for schizophrenics. In both groups, the 'cognitive cluster' loaded on the first 'positive' factor while the 'lack of insight' (LOI) has a different meaning in the two groups, more related to the positive symptoms in the bipolar patients and more related to the negative symptoms in the schizophrenic patients. This finding suggests that LOI could be a non-unitary phenomenon in psychoses and it should be further explored to better elucidate differences in symptom structures between schizophrenic and bipolar disorders.

Acute Disease↗

ChlVPP/EVA hybrid versus the weekly VAPEC-B regimen for previously untreated Hodgkin's disease.

PURPOSE: To test the hypothesis that a chemotherapy regimen of relatively low toxicity and 11 weeks' duration (doxorubicin, cyclophosphamide, etoposide, vincristine, bleomycin, and prednisolone [VAPEC-B]) is at least as effective in terms of disease control as 6 months' treatment with chlorambucil, vinblastine, procarbazine, and prednisone/etoposide, vincristine, and doxorubicin (ChlVPP/EVA hybrid), which is associated with a high risk of permanent sterility. PATIENTS AND METHODS: Two hundred eighty-two patients with previously untreated Hodgkin's disease, clinical stages I/II (plus mediastinal bulk and/or B symptoms) and clinical stages III/IV were randomized at three United Kingdom and one Italian center to receive either six monthly cycles of ChlVPP/EVA hybrid or 11 weekly cycles of VAPEC-B. After chemotherapy and a restaging evaluation, radiotherapy was administered to sites of previous bulk or residual radiographic abnormality before patients were observed off treatment. RESULTS: Further accrual to the trial was halted at the planned third interim analysis in September 1996. After a median follow-up of 4.9 years, freedom from progression (FFP), event-free survival (EFS), and overall survival (OS) are all significantly better in the population treated with ChlVPP/EVA than VAPEC-B, where the comparative 5-year results are 82% and 62% (FFP), 78% and 58% (EFS), and 89% and 79% (OS), respectively. The superiority of ChlVPP/EVA was seen in both low-risk and intermediate/high-risk patients, although subset analysis suggested that ChlVPP/EVA and VAPEC-B produce equivalent results in the best-prognosis patients (Hasenclever score <or= 2, nonbulky disease). CONCLUSION: Apart from possibly in the best-prognosis group, where results are equivalent, ChlVPP/EVA hybrid produces significantly better FFP, EFS, and OS than VAPEC-B in patients with previously untreated Hodgkin's disease.

Adolescent↗

Comparison of the genomes of two Xanthomonas pathogens with differing host specificities.

The genus Xanthomonas is a diverse and economically important group of bacterial phytopathogens, belonging to the gamma-subdivision of the Proteobacteria. Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, which affects most commercial citrus cultivars, resulting in significant losses worldwide. Symptoms include canker lesions, leading to abscission of fruit and leaves and general tree decline. Xanthomonas campestris pv. campestris (Xcc) causes black rot, which affects crucifers such as Brassica and Arabidopsis. Symptoms include marginal leaf chlorosis and darkening of vascular tissue, accompanied by extensive wilting and necrosis. Xanthomonas campestris pv. campestris is grown commercially to produce the exopolysaccharide xanthan gum, which is used as a viscosifying and stabilizing agent in many industries. Here we report and compare the complete genome sequences of Xac and Xcc. Their distinct disease phenotypes and host ranges belie a high degree of similarity at the genomic level. More than 80% of genes are shared, and gene order is conserved along most of their respective chromosomes. We identified several groups of strain-specific genes, and on the basis of these groups we propose mechanisms that may explain the differing host specificities and pathogenic processes.

Gene Order↗

Static coefficient of friction between Ti-6Al-4V and PMMA for cemented hip and knee implants.

The static coefficient of friction between Ti-6Al-4V and PMMA was determined experimentally. A microtopographic surface analysis of the Ti-6Al-4V and PMMA specimens used in the experiments was performed to characterize the surfaces. The coefficient of friction between Ti-6Al-4V and PMMA in both dry and wet conditions, using both Ringer's solution and bovine serum, was determined by the standard inclined plane test, following the ASTM 4516-91 method, and by a prototype computerized sliding friction tester. The effects of surface roughness and of contact pressure on the coefficient of friction also have been investigated. Tests were performed at 26 degrees C and at body temperature of 37 degrees C. Considering all the tests, the overall range of the mean coefficients of friction varied between 0.17 and 0.32 in dry or wet conditions. For the same surface roughness in contact, in general the coefficient of friction using Ringer's solution was slightly lower than it was in dry conditions whereas bovine serum had a very high surface tension, which significantly increased the static coefficient of friction.

Alloys↗

A novel approach for the analysis of DAZ gene copy number in severely idiopathic infertile men.

The deleted-in-azoospermia (DAZ) gene family constitutes the major candidate for the AZFc (azoospermia factor c) phenotype of male infertility, being deleted in about 10% of azoospermic and severely oligozoospermic subjects. Four DAZ genes are arranged in two clusters in AZFc, and standard analysis by PCR cannot distinguish among the different copies. Therefore only deletions of the entire gene cluster can be identified. We developed a PCR amplification-restriction digestion assay able to distinguish from DAZ genes for single nucleotide variants. Then we applied this approach to screen a group of idiopathic infertile men in which the DAZ genes presence was previously assessed by standard PCR analysis. Two patients out of 25 showed deletion of two copies of DAZ (DAZI and 2), suggesting that this mutation was actually the cause of spermatogenic damage. This preliminary screening demonstrates that deletions of copies of DAZ genes may be often found in severely infertile men and it strengthens the role of this gene family in spermatogenesis. Furthermore, this simple method, being able to distinguish among the different DAZ copies, could be used to screen a larger number of patients and to perform a more accurate diagnosis.

Deleted in Azoospermia 1 Protein↗

Attitudinal classification of patients receiving antibiotic treatment for mild respiratory tract infections.

The aim of this study was to determine patients' perceptions of antibiotic therapy and the doctor's skill in the management of ambulatory respiratory tract infections. Standardized face-to-face interviews were used with more than 3000 randomized patients or parents from four European countries. Attitudinal dimensions relating to their doctor identified four patient types: Involved (30%), Deferent (23%), Ignored (13%) and Critical (17%). Involved and Deferent patients were the most satisfied by the information received from their doctor (43%/39% compared with 17%/16% for Ignored/Critical, respectively, P < 0.01). They also scored more highly on the accurate use of antibiotics, with 80%/80% vs. 38%/62%, respectively (P < 0.01), understanding dosing intervals and 77%/77% vs. 36%/60% (P < 0.01), understanding the course length. Involved and Deferent patients showed better compliant behaviour, with 91% of both groups vs. 86% of the Ignored and Critical claiming to have taken every dose (P < 0.001) and 92%/87% vs. 84%/85% claiming to have finished the course (P < 0.001 for Involved only). Involved and Deferent patients were less prone to save part of a course of antibiotics than the Ignored and Critical (46%/41% vs. 20%/31%, P < 0.001), and they perceived the antibiotics prescribed to be more effective (36%/31% vs. 21%/15%, P < 0.001). By analysing patient perceptions, this study identifies an important mirror effect, whereby a more sympathetic attitude from the doctor should increase the patient's involvement in disease management, for a more appropriate use of antibiotics in common infections.

Adolescent↗

An Italian severe Salla disease variant associated with a SLC17A5 mutation earlier described in infantile sialic acid storage disease.

The present study reports two Italian brothers affected by severe Salla disease (sialic acid storage disease), a slowly progressive autosomal recessive neurodegenerative disorder prevalent in the Finnish population. Mutations of the SLC17A5 gene, which encodes a protein called sialin, are the primary cause of both Salla disease and infantile sialic acid storage disease (ISSD), a clinically distinct severe disorder. All Finnish patients with Salla disease show a R39C mutation. Both patients showed moderate intellectual disability, spastic ataxic syndrome, hypomyelination and cerebellar atrophy on magnetic resonance imaging (MRI), and lysosomal storage, all typical of Salla disease. Mutation analysis of the SLC17A5 gene in the younger brother revealed no R39C mutation, but a 15-bp deletion in exon 6 on one of the alleles. This mutation is the same described in French-Canadian patients with ISSD. Salla disease must be suspected in patients with unexplained psychomotor retardation associated with ataxia and/or pyramidal symptoms, and MRI findings consistent with cerebral hypomyelination, irrespective of the patient's ethnic origin. A mutation screening based on R39C change does not exclude Salla disease outside Finland. Conversely, mutations found in ISSD can be expected, even in patients showing the Salla phenotype (e.g. symptoms at the milder end of the spectrum).

Adolescent↗

Visualization of left atrial appendage and assessment of its function by transthoracic second harmonic imaging and contrast-enhanced pulsed Doppler.

BACKGROUND: Low flow velocity within the left atrial appendage, as assessed by transoesophageal echocardiography, is a predictor of thromboembolism and of a low success rate of cardioversion of atrial fibrillation. However, the semi-invasive nature does limit its serial application as a screening technique. METHODS AND RESULTS: We investigated the value of transthoracic second harmonic echocardiography and pulsed Doppler at baseline and after intravenous contrast injection to visualize the left atrial appendage and assess blood flow velocities within its cavity. We studied 51 consecutive patients undergoing transoesophageal echocardiography. After transoesophageal echocardiography, transthoracic second harmonic imaging was performed and the left atrial appendage was visualized in 46 patients. Interpretable pulsed Doppler tracings of left atrial appendage flow were obtained at baseline in 39 patients and in 45 patients during Levovist administration. The correlations between peak emptying velocity of left atrial appendage as measured by transoesophageal echocardiography and by transthoracic standard and contrast-enhanced Doppler were 0.81 and 0.91, respectively. The agreement between transoesophageal echocardiography and transthoracic contrast-enhanced pulsed Doppler echocardiography in classifying left atrial appendage flow velocity patterns was 93%. Left atrial appendage thrombus was detected by transthoracic second harmonic imaging in only one of the eight patients shown by transoesophageal echocardiography to have a thrombus. However, all but one of the patients with left atrial appendage thrombus and/or spontaneous echocardiographic contrast at transoesophageal echocardiography had <30cm/s left atrial appendage flow velocity by transthoracic Doppler. CONCLUSIONS: This study shows that left atrial appendage can be visualized by transthoracic second harmonic imaging and that the flow velocity within its cavity is reliably measured by pulsed Doppler in a substantial fraction of patients. Contrast enhancement improves the feasibility and the accuracy of transthoracic evaluation of left atrial appendage flow velocity. The practical value of these results in predicting thromboembolic risk and success of cardioversion of atrial fibrillation needs to be proved by prospective studies.

Aged↗

The inhibitory effect of propolis and caffeic acid phenethyl ester on cyclooxygenase activity in J774 macrophages.

The effect of an ethanolic extract of propolis, with and without CAPE, and some of its components on cyclooxygenase (COX-1 and COX-2) activity in J774 macrophages has been investigated. COX-1 and COX-2 activity, measaured as prostaglandin E2 (PGE2) production, were concentration-dependently inhibited by propolis (3 x 10(-3) - 3 x 10(2) microgml(-1)) with an IC50 of 2.7 microgml(-1) and 4.8 x 10(-2) microgml(-1), respectively. Among the compounds tested pinocembrin and caffeic, ferulic, cinnamic and chlorogenic acids did not affect the activity of COX isoforms. Conversely, CAPE (2.8 x 10(-4) - 28 microgml(-1); 10(-9) - 10(-4) M) and galangin (2.7 x 10(-4) - 27 microgml(-1); 10(-9) - 10(-4) M) were effective, the last being about ten-twenty times less potent. In fact the IC50 of CAPE for COX-1 and COX-2 were 4.4 x 10(-1) microgml(-1) (1.5 x 10(-6) M) and 2 x 10(-3) microgml(-1) (6.3 x 10(-9) M), respectively. The IC50 of galangin were 3.7 microgml(-1) (15 x 10(-6) M) and 3 x 10(-2) microgml(-1) (120 x 10(-9) M), for COX-1 and COX-2 respectively. To better investigate the role of CAPE, we tested the action of the ethanolic extract of propolis deprived of CAPE, which resulted about ten times less potent than the extract with CAPE in the inhibition of both COX-1 and COX-2, with an IC50 of 30 microgml(-1) and 5.3 x 10(-1) microgml(-1), respectively. Moreover the comparison of the inhibition curves showed a significant difference (p < 0.001). These results suggest that both CAPE and galangin contribute to the overall activity of propolis, CAPE being more effective.

Animals↗

Non-invasive proportional assist and pressure support ventilation in patients with cystic fibrosis and chronic respiratory failure.

BACKGROUND: Patients with advanced cystic fibrosis can benefit from non-invasive positive pressure ventilation (NPPV) for the treatment of acute decompensation as well as for the management of chronic respiratory failure. This study was undertaken to compare the physiological effects of non-invasive proportional assist ventilation (PAV) and pressure support ventilation (PSV) on ventilatory pattern, transcutaneous blood gas tensions, and diaphragmatic effort in stable patients with cystic fibrosis and chronic CO2 retention. METHODS: In 12 patients two periods of spontaneous breathing were followed randomly by PSV (12 (3) cm H2O) and PAV (flow assist 4.9 (1.3) cm H2O/l.s, volume assist 18.9 (5.1) cm H2O/l) set for the patient's comfort and administered for 40 minutes with 2 cm H2O continuous positive airway pressure. Ventilatory pattern, transcutaneous blood gas tensions, and surface diaphragmatic electromyography were measured in the last 10 minutes of each application. RESULTS: On average, both PSV and PAV improved ventilation (+30%), tidal volume (+30%), and transcutaneous CO2 (-7%) while reducing diaphragmatic activity (-30% with PSV, -20% with PAV). Mean inspiratory airway pressure was lower during PAV than during PSV (9.7 (1.9) and 12.9 (2.7) cm H2O, respectively; p<0.05). The mean coefficient of variation of tidal volume was about 20% (range 11-39%) during spontaneous breathing and did not change with either PAV or PSV. CONCLUSIONS: These results show that short term administration of nasal PAV and PSV to patients with stable cystic fibrosis with chronic respiratory insufficiency is well tolerated, improves ventilation and blood gas tensions, and unloads the diaphragm.

Adult↗

Zolmitriptan versus a combination of acetylsalicylic acid and metoclopramide in the acute oral treatment of migraine: a double-blind, randomised, three-attack study.

This multicentre, randomised, double-blind study compared oral zolmitriptan 2.5 mg with a combination of oral acetylsalicylic acid 900 mg and metoclopramide 10 mg as acute anti-migraine therapy for 3 migraine attacks. In total, 666 patients took at least one dose of study medication (326 took zolmitriptan and 340 took acetylsalicylic acid plus metoclopramide). The percentage of patients with a 2-hour headache response after the first dose for all 3 attacks (the primary end point) was 33.4% with zolmitriptan and 32.9% with acetylsalicylic acid plus metoclopramide [odds ratio 1.06, 95% confidence interval (CI) 0.77-1.47; p = 0.7228]. For the majority of secondary end points, the two treatments demonstrated comparable efficacy. However, post hoc analysis showed that significantly more patients receiving zolmitriptan were free of pain 2 h after the first dose in all 3 attacks compared with patients receiving acetylsalicylic acid plus metoclopramide (10.7 vs. 5.3%; odds ratio 2.19, 95% CI 1.23-4.03; p = 0.0095). In addition, post hoc analysis showed that the overall 2-hour pain-free response rate was consistently higher with zolmitriptan (34.6%) than with acetylsalicylic acid plus metoclopramide (27.9%) (odds ratio 1.40, 95% CI 1.09-1.78; p = 0.007). Both treatments reduced migraine-associated nausea, vomiting, phonophobia and photophobia. There were no important inter-group differences with respect to the onset of meaningful migraine relief, the frequency of headache recurrence, the usage or efficacy of a second dose of medication or the use of escape medication. However, at the last attack, the proportion of patients who expressed overall satisfaction with the treatment was significantly higher in the zolmitriptan group, i.e. 83.7%, versus 75.0% with acetylsalicylic acid plus metoclopramide (p = 0.0346). Both agents were well tolerated. Adverse events were reported by 40.8% (133/326) of zolmitriptan-treated patients and 29.1% (99/340) of those treated with acetylsalicylic acid plus metoclopramide. The incidence of withdrawals due to adverse events was very low with both zolmitriptan (0.9%) and the combination regimen (1.5%); the latter percentage included 1 patient who withdrew from the study due to phlebitis, which was classified as a serious adverse event. This study showed that zolmitriptan is effective and well tolerated for the acute treatment of moderate to severe migraine. Zolmitriptan was at least as effective as acetylsalicylic acid plus metoclopramide in achieving a 2-hour headache response, but significantly more effective than the combination therapy for other end points, including the 2-hour pain-free response.

Acute Disease↗

The Italian multicentre study on noninvasive ventilation in chronic obstructive pulmonary disease patients.

Chronic obstructive pulmonary disease (COPD) patients with chronic ventilatory failure (CVF) are more likely to develop exacerbations, which are an important determinant of health-related quality of life (HRQL). Long-term noninvasive positive-pressure ventilation (NPPV) has been proposed in addition to long-term oxygen therapy (LTOT) to treat CVF but little information is available on its effects on HRQL and resource consumption. Therefore, the current authors undertook a 2-yr multicentric, prospective, randomised, controlled trial to assess the effect of NPPV+ LTOT on: 1) severity of hypercapnia; 2) use of healthcare resources, and 3) HRQL, in comparison with LTOT alone. One hundred and twenty-two stable hypercapnic COPD patients on LTOT for > or = 6 months were consecutively enrolled. After inclusion and 1-month run-in, 90 patients were randomly assigned to NPPV+LTOT (n=43) or to LTOT alone (n=47). Arterial blood gases, hospital and intensive care unit (ICU) admissions, total hospital and ICU length of stay and HRQL were primary outcome measures; survival and drop-out rates, symptoms (dyspnoea and sleep quality) and exercise tolerance were secondary outcome measures. Follow-up was performed at 3-month intervals up to 2 yrs. Lung function, inspiratory muscle function, exercise tolerance and sleep quality score did not change over time in either group. By contrast the carbon dioxide tension in arterial blood on usual oxygen, resting dyspnoea and HRQL, as assessed by the Maugeri Foundation Respiratory Failure Questionnaire, changed differently over time in the two groups in favour of NPPV+LTOT. Hospital admissions were not different between groups during the follow-up. Nevertheless, overall hospital admissions showed a different trend to change in the NPPV+LTOT (decreasing by 45%) as compared with the LTOT group (increasing by 27%) when comparing the follow-up with the follow-back periods. ICU stay decreased over time by 75% and 20% in the NPPV+LTOT and LTOT groups, respectively. Survival was similar. Compared with long-term oxygen therapy alone, the addition of noninvasive positive-pressure ventilation to long-term oxygen therapy in stable chronic obstructive pulmonary disease patients with chronic ventilatory failure: 1) slightly decreased the trend to carbon dioxide retention in patients receiving oxygen at home and 2) improved dyspnoea and health-related quality of life. The results of this study show some significant benefits with the use of nocturnal, home noninvasive positive-pressure ventilation in patients with chronic ventilatory failure due to advanced chronic obstructive pulmonary disease patients. Further work is required to evaluate the effect of noninvasive positive-pressure ventilation on reducing the frequency and severity of chronic obstructive pulmonary disease exacerbation.

Aged↗