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At least 721 records · Page 40Linked to original sources
PubMed2000

Lung volume reduction surgery does not improve diaphragmatic contractile properties or atrophy in hamsters with elastase-induced emphysema.

It is claimed that lung volume reduction surgery (LVRS) improves inspiratory muscle function. As diaphragm structure and function are not directly appraisable in patients, we studied the effects of LVRS on the diaphragm in vitro contractile properties and morphology in hamsters with elastase-induced emphysema. Four months after intratracheal instillation of elastase (40 U/100 g), hamsters underwent either bilateral LVRS (LVRS, n = 11) or a sham operation (SHAM, n = 8). Four animals died during the perioperative period in LVRS (n = 7). Hamsters instilled with saline served as control (CTL, n = 8). Animals were studied at the age of 9 mo. LVRS was associated with a significant 25% decrease in functional residual capacity compared to SHAM (p < 0.05). Compared with CTL, LVRS and SHAM showed a significant 18% and 14% reduction in diaphragm mass, respectively (p = 0.02). LVRS had a significantly decreased twitch tension compared to CTL and SHAM (p < 0.01). Both LVRS and SHAM showed increased resistance to muscle fatigue compared with CTL. The histochemical analysis revealed a significant shift from type IIx/b toward type IIa fibers in LVRS and SHAM compared with CTL. In conclusion, emphysema is associated with functional adaptations but LVRS does not appear to beneficially alter the diaphragm contractile and morphological characteristics in hamsters with elastase-induced emphysema.

Animals↗
PubMed1999

Protective effect of left ventricular hypertrophy in right coronary artery occlusions.

OBJECTIVE: To test the hypothesis that left ventricular hypertrophy (LVH) reduces the electrocardiographic and functional effects of right coronary artery occlusion. METHODS: We analysed 215 patients (166 males and 49 women, age of 58.9 +/- 10.6 years), with occlusion of the right coronary artery without other associated lesions. There was no significant difference (p > 0.05) in age and gender distribution between the 78 patients with LVH (left ventricular mass > 100 g/m2) (Group A) when compared with the 137 patients without LVH (left ventricular mass < 100 g/m2) (Group B). RESULTS: The electrocardiographic finding of transmural necrosis was more often found in group B patients than in group A patients (56.9% and 30.8%, respectively; p < 0.05). The left ventricular function parameters of group A were better than those of group B: the ratio end-diastolic pressure/systolic pressure (EDP/SP) (A: 0.108 +/- 0.036; B: 0.121 +/- 0.050; p < 0.05); the end-diastolic volume index (A: 75.9 +/- 31.3 ml/m2; B: 88.0 +/- 31.0 ml/m2; p < 0.01); the end-systolic volume index (A: 16.0 +/- 10.0 ml/m2; B: 27.0 +/- 20.0 ml/m2; p < 0.001); the ejection fraction (A 78.6 +/- 10.8%; B 67.7 +/- 17.9%; p < 0.001); the anteroinferior shortening (A: 43.9 +/- 10.3%; B: 35.1 +/- 12.8%; p < 0.001). A higher degree of coronary tortuosity was observed in group A than in group B (78.2% and 24.1%; p < 0.001) and also a more frequent absent or minimal diaphragmatic hypokinetic area (A: 80.8%; B: 54.0%; p < 0.05). CONCLUSION: LVH reduces the effects of myocardial sequela and protects LV function when right coronary occlusion develops.

Cohort Studies↗
PubMed2000

Administration of antenatal glucocorticoids upregulates peptide growth factor gene expression in nitrofen-induced congenital diaphragmatic hernia in rats.

BACKGROUND/PURPOSE: There is increasing evidence to suggest that various growth factors play a crucial role in fetal lung growth and morphogenesis. An array of peptide growth factors regulate cell proliferation, differentiation, and various other cell functions in the developing lung. The aim of this study was to investigate the effect of antenatal glucocorticoids administration on gene expression of basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF) and transforming growth factor (TGF)-beta1 in nitrofen-induced congenital diaphragmatic hernia (CDH) in rats. METHODS: A CDH model was induced in pregnant rats after administration of nitrofen. Dexamethasone (Dex; 0.25 mg/kg) was given intraperitoneally on day 18.5 and 19.5 of gestation (term, day 22). Cesarean section was performed on day 21 of gestation. mRNA was extracted from left lung and reverse transcription-polymerase chain reaction (RT-PCR) was performed to evaluate mRNA expression of each growth factors. Relative levels of mRNA were expressed as a ratio of the band density divided by that of beta-actin, a housekeeping gene known to be expressed at a constant level. RESULTS: Relative mRNA levels of bFGF and TGF-beta1 were decreased significantly in CDH lung compared with controls. Antenatal Dex treatment up-regulated gene expression of bFGF, PDGF, and TGF-beta1 in the hypoplastic CDH lung. CONCLUSIONS: The authors' findings suggest that decreased gene expression of bFGF, PDGF, and TGF-beta1 in the CDH lung may suppress lung growth and development. Increased gene expression of bFGF, PDGF, and TGF-beta1 in Dex-treated lung suggests that antenatal glucocorticoid administration may accelerate fetal lung growth by up-regulating these growth factors.

Animals↗
PubMed2003

Development of the peritoneal lymphatic stomata and lymphatic vessels of the diaphragm in mice.

The generation and development of the peritoneal lymphatic stomata (PLS) and lymphatic vessels of the diaphragm were studied in mice at gestational ages from the embryonic to the postnatal period with TEM, SEM and enzyme histochemistry and the PLS data were quantitatively analyzed with computer-assisted image processing technology (Elescope image analysis software). The results showed that the diaphragmatic mesothelium was covered only by flattened mesothelial cells (FMC) at the 13th embryonic day (ED 13). At ED 15, some cuboidal mesothelial cells (CMC) and immature lymphatic stomata (NLS) were found scattered on the diaphragmatic mesothelium. The sub-peritoneal lymphatic capillaries did not appear until ED 18. However, no absorptive function was observed in NLS when trypan blue granules were injected into the peritoneal cavity. At postnatal day 1 (PND 1), the endothelial cytoplasm processes of the diaphragm lymphatic capillaries span the connective tissue fibers and the basal membrane of CMC to form the subperitoneal channels. These channels were connected with NLS and serve as the absorptive route between the peritoneal cavity and the sub-peritoneal lymphatic vessels. The trypan blue absorption test demonstrated that postnatal PLS possessed an absorptive function and had transformed to mature lymphatic stomata (MLS) by PND 1. Thus, NLS were renamed of MLS. At PND 5, the cuboidal mesothelial cell ridge (CMCR) appeared with increased CMC areas. At PND 10, CMCR were fused to form the band-like CMC area with much more MLS distributed in the muscular portion of the diaphragm. With distribution area and density of PLS increasing and growth of lymphatic vessels, an increased absorptive function from the peritoneal cavity was observed in the experiment.

Animals↗
PubMed2002

Long term results of diaphragmatic plication for unilateral diaphragm paralysis.

OBJECTIVES: To examine whether diaphragmatic plication is an effective and lasting treatment option for non-malignant diaphragmatic paralysis. METHODS: Nineteen patients who had undergone diaphragm plication (1983-1990) were recalled for interview, pulmonary function testing and chest X-ray. RESULTS: There were 13 men and six women aged 24-73 (mean 55). Diaphragm paralysis was idiopathic (n=9), postsurgical (n=3), related to cervical spondylosis (n=4) and neck injury (n=2). Patients presented with breathlessness (18/19) or orthopnoea (1/19). Symptoms had lasted 3-60 months (mean 24 months). All patients had a raised hemidiaphragm on chest X-ray with paradoxical movement on ultrasound. Mean preoperative FVC was 71% predicted (range 38-93, SD 12.9) and mean FEV(1) was 67% predicted (range 33-90, SD 10.8). Supine lung volumes were 81% (mean) of sitting values. There were six right plications and 13 left. There were no postoperative deaths. One patient required re-plication. Follow-up (18/19 of original operated patients) ranged from 7-14 years (mean 10 years). Three patients had died of unrelated causes and one patient failed to attend long term follow-up, leaving 15 patients of the original 19 operated on. Positional change in lung volumes was not affected by surgery at early (6 week) or late (>5 year) follow-up. FVC, FEV(1), FRC and TLC improved by 10.1*, 11.8*, 16.9* and 9.2*%, respectively, at early follow-up and 11.8*, 15.4*, 26 and 13.3*% at late follow-up (*P<0.005 signed rank). Dyspnoea scores at long term follow-up improved 1 point (n=5), 2 points (n=5) and 3 points (n=2), remained unchanged (n=1) or dropped 1 point (n=2). Of the 15 patients followed up all but one who had been employed returned to work. 14/15 patients expressed satisfaction with their surgery. CONCLUSION: Diaphragm plication is an effective procedure with lasting results.

Adult↗
PubMed1991

The ventilatory pump: neonatal and developmental issues.

This review documents the current knowledge with regard to the structure and function of the developing ventilatory pump. We note that while the neonate's compliant rib cage and diaphragmatic configuration may predispose the newborn to pump failure, its diaphragmatic endurance properties and ability to recruit accessory muscles of respiration may protect against such impairment. We also share evidence that central neural failure can lead to an inability to defend minute ventilation during periods of heightened respiratory effort. Nevertheless, our fund of knowledge remains limited and at this juncture it is unclear which factors or interplay of factors contribute to the development of ventilatory failure in the human neonate and infant. The ventilatory pump is a vital component of the respiratory system. As such, our understanding of the pathogenesis and reversal of ventilatory pump impairment is crucial to improving our management of respiratory failure. We are only beginning to develop such an understanding within a neonatal and developmental context. Future research endeavors will enlarge our fund of knowledge regarding the thorax, the respiratory muscles, and the central neural respiratory-related neurons that control them. From such an understanding will emerge clinically relevant information that has therapeutic implications for the care of newborns and infants with respiratory disease.

Adult↗
PubMed1985

Idiopathic bilateral diaphragmatic paralysis.

A patient with dyspnoea was found to have a complete diaphragmatic paralysis due to a bilateral phrenic nerve lesion, without evidence of a generalized neuromuscular disease. The functional sequelae of breathing with intercostal and auxiliary inspiratory muscles were studied in the patient both while awake and asleep. This we believe is the second case of idiopathic bilateral paralysis of the diaphragm described in the literature.

Electromyography↗
PubMed1996

Central and peripheral respiratory electrophysiological studies in myotonic dystrophy.

Acute and chronic respiratory failure is a common and potentially life-threatening feature in patients with myotonic dystrophy (MD). The causes may be varied, and can involve both the central and peripheral nervous system. To evaluate the incidence of respiratory muscle involvement and the function of the central motor inspiratory pathway to phrenic motor neurons we performed magnetic stimulation of the cortex and cervical spinal cord, phrenic nerve conduction studies and needle EMG of diaphragm and intercostal muscles in 25 patients with MD. The results were compared with those from 35 healthy subjects. In addition, pulmonary function tests, blood gas analyses and static mouth pressures were evaluated. Abnormalities in response to magnetic stimulation, including a reduced compound muscle action potential (CMAP) from the diaphragm and increased excitability threshold, indicated impaired central inspiratory drive in 20% of cases. Phrenic nerve conduction showed a reduced diaphragmatic CMAP amplitude in 20%, and a delayed negative peak onset latency in 4% of cases. Abnormalities in diaphragm and intercostal muscle needle EMG were found in 76% of cases, these were mainly myotonic discharges (68%) and a decrease in the number of active motor units (36%). Patients with abnormal respiratory electrophysiological parameters had a significantly lower functional vital capacity (FVC; P = 0.005). The duration of the disease correlated negatively with diaphragmatic CMAP amplitude to phrenic nerve, but not magnetic, stimulation. Our results demonstrate that the involvement of the central inspiratory pathway is common in MD patients. Central and peripheral electrophysiological studies of the diaphragm should be considered in the diagnosis and management of patients with MD and dyspnoea.

Adult↗
PubMed1996

Extended indications for lung volume reduction surgery in advanced emphysema.

BACKGROUND: Lung volume reduction surgery has shown early promise as a palliative therapy in severe emphysema. Selection of potential candidates has been based on certain functional and anatomic criteria, and a variety of operative contraindications have been proposed. METHODS: Over 15 months, we performed lung volume reduction surgery in 85 patients selected on the basis of severe hyperinflation with air trapping, diaphragmatic dysfunction, and disease heterogeneity. Patients were not excluded on the basis of severe hypercapnia, steroid dependence, profound pulmonary dysfunction, or inability to complete preoperative rehabilitation. RESULTS: We observed significant improvements in pulmonary function, exercise capacity, and dyspnea, with an acceptable 30-day perioperative mortality of 7% and actuarial survival of 90% and 83% at 6 and 12 months, respectively. In each "high-risk" group, perioperative mortality, actuarial survival to 1 year, and functional results were equivalent, and in some cases superior, to those in the corresponding "low-risk" patients. CONCLUSIONS: Severe hypercapnia, steroid dependence, profound pulmonary dysfunction, and inability to complete preoperative rehabilitation do not preclude successful lung volume reduction surgery and should not be regarded as absolute exclusionary criteria.

Aged↗
PubMedDate not supplied

Selective diaphragmatic mitochondrial abnormalities in a patient with marked air flow obstruction.

There is increasing evidence that exercise overload induces changes in skeletal muscle structure and function. Recent studies suggest that muscle mitochondria could be involved either as the result or the origin of these changes. This study describes a case of a patient with marked air flow obstruction related to chronic obstructive pulmonary disease, in which large aggregates of mitochondria were found in diaphragm muscle fibers. Many of the mitochondria contained paracrystalline rectangular inclusions. Latissimus dorsi and intercostal muscles were also available for ultrastructural examination that showed, respectively, normal and moderately increased number of mitochondria with normal mitochondrial structure. This is the first known report of paracrystalline rectangular inclusions in respiratory skeletal muscle from a patient with chronic obstructive pulmonary disease.

Carcinoma, Squamous Cell↗
PubMed1998

[Effects of a short-term pulmonary rehabilitation program on patients with chronic respiratory failure due to pulmonary emphysema].

To evaluate the effects of a short-term pulmonary rehabilitation program on dyspnea, exercise capacity, and lung function, 15 patients with chronic respiratory failure due to pulmonary emphysema were enrolled in such a program for 3 weeks as inpatients. The program consisted of pursed lip breathing, diaphragmatic breathing, respiratory muscle stretch gymnastics, and walking with synchronized breathing. Dyspnea as measured with a visual analogue scale at the end of a 6-minute walk before and after the program (49.7 +/- 4.0% to 24.2 +/- 3.8%) decreased significantly (p < 0.01). As a measure of functional exercise capacity, the 6-minute walking distance (226.9 +/- 32.4 m to 292.1 +/- 35.8 m) increased significantly (p < 0.01). As an indicator of maximal exercise capacity, endurance time on an incremental treadmill test did not improve. Spirometric data did not change during the study. Total lung capacity (TLC) (8.44 +/- 0.70 L to 7.58 +/- 0.74 L) and residual volume (RV) (5.13 +/- 0.53 L to 4.28 +/- 0.59 L) decreased significantly (p < 0.01). The findings suggest that this program relieves dyspnea, increases functional exercise capacity, and decreases TLC and RV on patients with chronic respiratory failure due to pulmonary emphysema.

Aged↗
PubMed1987

Pulmonary restrictive effect of bracing in mild idiopathic scoliosis.

The use of bracing in the treatment of mild idiopathic scoliosis is controversial. A study of 33 adolescents showed that bracing significantly decreased lung volumes. Functional residual capacity was reduced by a mean of 26%, 18% of children showing a reduction of greater than 40%. The mean reduction in total lung capacity was 16% and in forced vital capacity 18%. This restriction of lung function by bracing might have a deleterious effect on lung growth or might impose an additional risk factor in the presence of other disorders, such as asthma and diaphragmatic weakness. The use of bracing in individuals with mild scoliosis should be judiciously reassessed.

Adolescent↗
PubMed1987

[Respiratory manifestations of ankylosing spondylitis (50 cases)].

Fifty patients with ankylosing spondylitis underwent radiography of the chest. In addition, 2 of them had bronchography, 3 had computerized tomography (CT) of the chest, 9 had respiratory function tests and 8 head ventilation/perfusion study by the Xenon method. Seven thoracic images were questionably specific of spondylitis, showing plural symphysis, strips of atelectasis, pleural thickening, apical pulmonary sclerosis and opacities of the diaphragmatic hilum. CT proved valuable in 1 case to confirm pulmonary fibrosis and in 2 cases to reveal that pleural thickening was continuous with an opacity ensheathing the vertebral body. In 7 out of 9 cases the functional restrictive deficit was accompanied by normal or supranormal functional residual capacity and increased residual volume. In all patients explored by the Xenon method, there was apical-caudal inversion of the ventilation/perfusion ratio. These findings suggest 3 pathogenic hypotheses: mere sequelae of hypoventilation, specific lung tissue fibrosis, extension by continuity of the vertebra-ensheathing process to the subpleural spaces.

Humans↗
PubMed2000

Nutritional supplementation in stable chronic obstructive pulmonary disease.

BACKGROUND: Low body weight in patients with chronic obstructive pulmonary disease (COPD) is associated with an impaired pulmonary status, reduced diaphragmatic mass, lower exercise capacity and higher mortality rate when compared to adequately nourished individuals with this disease. Nutritional support may therefore be a useful part of their comprehensive care. OBJECTIVES: To conduct a systematic review of randomized controlled trials (RCTs) to clarify whether nutritional supplementation (caloric supplementation for at least 2 weeks) improved anthropometric measures, pulmonary function, respiratory muscle strength and functional exercise capacity in patients with stable COPD. SEARCH STRATEGY: Randomized controlled trials (RCTs) were identified from the Cochrane Airways Group register of RCTs, a hand-search of abstracts presented at international meetings and consultation with experts. SELECTION CRITERIA: Two reviewers independently selected trials for inclusion, assessed quality and extracted the data. DATA COLLECTION AND ANALYSIS: Within each trial and for each outcome, we calculated an effect size. The effect sizes were then pooled by a random-effects model. Homogeneity among the effect sizes was also tested. MAIN RESULTS: From 272 references, nine RCTs were ultimately included. Six papers were considered as high quality and only two studies were double-blinded. For each of the outcomes studied, the effect of nutritional support was small: the 95% confidence intervals around the pooled effect sizes all included zero. The effect of nutritional support was homogeneous across studies. REVIEWER'S CONCLUSIONS: Nutritional support had no significant effect on anthropometric measures, lung function or exercise capacity in patients with stable COPD.

Enteral Nutrition↗
PubMed2004

Trolox attenuates mechanical ventilation-induced diaphragmatic dysfunction and proteolysis.

Prolonged mechanical ventilation results in diaphragmatic oxidative injury, elevated proteolysis, fiber atrophy, and reduced force-generating capacity. We tested the hypothesis that antioxidant infusion during mechanical ventilation would function as an antioxidant to maintain redox balance within diaphragm muscle fibers and therefore prevent oxidative stress and subsequent proteolysis and contractile dysfunction. Sprague-Dawley rats were anesthetized, tracheostomized, and mechanically ventilated with 21% O(2) for 12 hours. The antioxidant Trolox was intravenously infused in a subset of ventilated animals. Compared with acutely anesthetized, nonventilated control animals, mechanical ventilation resulted in a significant reduction (-17%) in diaphragmatic maximal tetanic force. Importantly, Trolox completely attenuated this mechanical ventilation-induced diaphragmatic contractile deficit. Total diaphragmatic proteolysis was increased 105% in mechanical ventilation animals compared with controls. In contrast, diaphragmatic proteolysis did not differ between controls and mechanical ventilation-Trolox animals. Moreover, 20S proteasome activity in the diaphragm was elevated in the mechanical ventilation animals (+76%); Trolox treatment attenuated this mechanical ventilation-induced rise in protease activity. These results are consistent with the hypothesis that mechanical ventilation-induced oxidative stress is an important factor regulating mechanical ventilation-induced diaphragmatic proteolysis and contractile dysfunction. Our findings suggest that antioxidant therapy could be beneficial during prolonged mechanical ventilation.

Animals↗
PubMed1982

Traumatic diaphragmatic hernias: a report of 19 cases.

From an analysis of 19 patients with traumatic diaphragmatic hernias with respect to the type of injury, associated injuries, clinical and radiologic features, diagnosis, surgical management and causes of death and from a review of the literature, the authors draw a number of conclusions. 1. Careful clinical examination coupled with an accurate interpretation of the roentgenograms should detect most cases of traumatic rupture of the diaphragm. 2. Impairment of respiratory function, possibility of strangulation and incarceration of the abdominal viscera demand early repair. 3. The choice of incision and approach depends on the stage at which the rupture is recognized (early or late), the site of rupture and the associated injuries. 4. Careful assessment of respiratory function should be made in order to prevent postoperative complications; in some cases respiration must be assisted. 5. Although the mortality in patients with traumatic diaphragmatic rupture is still relatively high, the deaths sould not be related to the rupture per se, or to its repair, but rather to the associated injuries.

Adolescent↗