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Query: UMLS:C0034067 (emphysema)
 11,506 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The weight of the diaphragm has been investigated in 103 male patients and 81 female patients, and the relationship between body weight and emphysema has been assessed in 662 male and 431 female patients. Diaphragm weight is related to body weight in both male (r = + 0.76) and female patients (r = +0.77) and is relatively larger in the former. Dissecting the diaphragm free of fat or freeze drying it does not appreciably improve the relationship between body weight and diaphragm weight. Diaphragm weight is better related to body weight than body length and is diminished in emphysema. Patients with emphysema weigh less. This is apparent with only moderate grades of emphysema, and there is no further loss of body weight as emphysema in the lung becomes more severe. The loss of diaphragm weight not only reflects the loss of body weight that occurs in emphysema, but the diaphragm is also less in weight than predicted from body weight. The diaphragm also appears abnormal on gross inspection in some patients with emphysema. Heart weight and diaphragm weight are related, probably because both are related to body weight.
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PMID:Diaphragm and body weight in emphysema. 69 1

In adult male hamsters the influence of emphysema (EMP) on the in vitro contractile and fatigue properties and the histochemical, morphometric, and metabolic properties of muscle fibers in the costal diaphragm was determined 6 mo after the administration of either elastase or saline (controls, CTL). Isometric contractile properties were determined in vitro using supramaximal direct muscle stimulation. Optimal fiber length for force generation was significantly shorter in the EMP than in the CTL diaphragm. Maximum specific force (i.e., force per unit area) was 25% lower than CTL. Fatigue resistance was significantly improved in the EMP diaphragm compared with CTL. Diaphragm muscle fibers were classified as type I or II on the basis of histochemical staining for myofibrillar adenosinetriphosphatase after alkaline preincubation. The proportions of type I and II fibers were similar between the two groups. Cross-sectional areas of type II fibers were 30% larger in EMP than in CTL diaphragms. Succinate dehydrogenase activities of both type I and II fibers were higher in EMP than in CTL diaphragms. The number of capillaries surrounding both type I and II fibers increased with EMP, but in proportion to the hypertrophy of these fibers. Thus, capillary density (number of capillaries per fiber cross-sectional area) remained unchanged. We postulate that these contractile, morphometric, and metabolic adaptations reflect an increased activation of the diaphragm in response to the loads imposed by EMP.
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PMID:Adaptations of the diaphragm in emphysema. 156 89

To determine the normal morphologic evolution of the diaphragm with aging and to correlate age-related changes with other indicators of physical condition--such as skeletal muscle status, obesity, presence of pulmonary emphysema, and presence of esophageal hiatus hernia--a systematic morphometric and morphologic evaluation of computed tomographic studies of 120 patients from the 3d to 8th decades of life was undertaken. Diaphragm muscle thickness did not change significantly with increasing age. Diaphragmatic defects and pseudotumors, nonexistent in the 3d and 4th decades, increased in number and severity to affect 56% of the patients in the 7th and 8th decades. Neither the status of the skeletal muscle nor the presence of obesity correlated with age or with the presence of diaphragmatic defects. Eighty-four percent of the patients with emphysematous changes demonstrated diaphragmatic defects; thus, a strong association with emphysema was observed. If emphysematous patients are excluded, defects were more common in women. The esophageal hiatus width was found to increase with age.
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PMID:Aging of the diaphragm: a CT study. 270 2

A 61-year-old man suffering from severe pulmonary emphysema underwent lung volume reduction surgery on both upper lobes. By one year after surgery functional residual capacity had decreased by 2.5 L and FEV1 had increased by a factor of 2.4. Diaphragm excursion, as assessed by dynamic magnetic resonance imaging, had increased and ventilation and pulmonary gas exchange had improved. Performance on a 6-minute-walk test and exercise tolerance measured on a bicycle ergometer improved, and both peak VE and VO2 increased. Before surgery, pulmonary artery pressure Ppa and pulmonary capillary wedge pressure Pewp during exercise were abnormally high, but 6 months after the operation the increases in Ppa and Pcwp during exercise were markedly reduced.
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PMID:[Effects of bilateral lung volume reduction surgery in a patient with severe pulmonary emphysema]. 916 56

Aim of this work is to present and discuss the radiologic protocol we have developed for the preoperative assessment of patients with severe pulmonary emphysema candidate to lung volume reduction surgery (LVRS). The operation aims at improving respiratory mechanics and reducing small airway obstruction by removing variable amounts of emphysematous parenchyma. January to September, 1996, twelve patients were submitted to LVRS. Before surgery all patients were examined with standard chest radiographs during maximal inspiration and expiration, chest Computed Tomography (CT), High Resolution Computed Tomography (HRCT) and air trapping quantitation on HRCT scans. Diaphragm and chest wall excursions, patterns, site and distribution of emphysema, as well as heterogeneity (i.e., the uneven distribution of emphysematous and normal parenchyma) were investigated. Air trapping was quantitated with a dedicated software. Postoperative studies were carried out 2 months later in six patients and included: maximal inspiratory and expiratory chest radiographs and air trapping assessment on 3 standardized HRCT scans. All parameters considered improved in every patient. Radiologic studies proved to be of crucial importance for patient selection and LVRS planning. Despite our limited number of patients, the diagnostic protocol adopted in our Hospital appears a valuable tool for both pre- and post-operative assessment of the patients candidate to LVRS.
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PMID:[Radiologic assessment in lung volume reduction surgery in emphysema]. 924 14

This study was designed to investigate whether the administration of the anabolic steroid nandrolone decanoate is able to antagonize the loss in diaphragm function induced by long-term administration of a low-dose of methylprednisolone in emphysematous hamsters. Normal and emphysematous male hamsters were randomized to receive either saline or methylprednisolone 0.2 mg x kg(-1) x day(-1) for 9 months, with or without nandrolone decanoate 1 mg x kg(-1) x week(-1) i.m. during the final 3 months. Diaphragm contractile properties and myosin heavy chain composition were determined. Compared to control hamsters, the force generating capacity of isolated diaphragm strips decreased by approximately 12% in the emphysema group and by approximately 22% in the emphysema plus methylprednisolone group. Addition of nandrolone decanoate to the emphysema plus methylprednisolone hamsters significantly improved force generation. The atrophy of type IIa and IIx diaphragm fibres in the emphysema plus methylprednisolone group was completely reversed to the level of control hamsters by the addition of nandrolone decanoate. In conclusion, nandrolone decanoate in part reversed the loss in diaphragm force-generating capacity in emphysematous hamsters treated with methylprednisolone, and reversed type IIa and IIx fibre atrophy completely.
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PMID:Effects of anabolic steroids on diaphragm impairment induced by methylprednisolone in emphysematous hamsters. 1041 5

Lung hyperinflation is a consequence of airway obstruction, increased airway resistance and compliance in patients with chronic obstructive pulmonary disease (COPD) which may result in respiratory muscle fatigue and deterioration of gas transfer. The aim of this study was to investigate the influence of hyperinflation on respiratory muscles, gas transfer and breathing pattern and compare the differences between mild and severe COPD. Twenty-eight COPD patients with radiological and tomographic evidence of emphysema were included in the study and they were divided into two groups according to the severity of COPD. Group I= FEV(1) < or = 49% (n= 16). Group II= FEV(1) > or = 50% (n= 12). Airflow rates were decreased and airway resistance was increased significantly in Group I. Maximal inspiratory pressure (MIP) was significantly reduced in Group I. FRC, RV and RV/TLC ratio were increased above 120% in both groups with more significant increase in Group I. Group I showed moderate hypoxemia (PaO(2) = 54.02 mmHg) with hypercapnia (PaCO(2)= 46.65 mmHg) whereas Group II patients were mildly hypoxemic (PaO(2)= 63.78 mmHg) with normocapnia. Parameters of breathing pattern were similar in both groups. Diaphragm height index (DHI) didn't showed significant difference between groups. But there were significant correlations between DHI and RV, FRC. MIP showed significant positive correlation with airflow rates and DLCO, negative correlation with lung volumes, positive correlation with PaO(2) and negative correlation with PaCO(2). FRC also negatively correlated with Ti and Ti/Ttot. In conclusion, hyperinflation present even in the mild forms of COPD causes inspiratory muscle weakness which in return results in impairment in gas transfer.
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PMID:[The effect of hyperinflation on respiratory muscles and breathing pattern in COPD]. 1514 1

With emphysema, diaphragm length adaptation results in shortened fibers. We hypothesize that passive diaphragm stretch occurring acutely after lung volume reduction surgery (LVRS) results in fiber injury. Bilateral LVRS was performed in emphysematous hamsters. Studies were performed 1 (D1) and 4 (D4) days after LVRS, and compared with sham-treated groups. Sarcolemmal rupture was evident in 10.9% of fibers in LVRS-D1 and reduced to 1.6% in LVRS-D4. Ultrastructural analysis revealed focal abnormalities in both LVRS-D1 and LVRS-D4 animals in over one-third of fibers. Myofibrillar disruption was not observed in sham-treated animals. Diaphragm insulin-like growth factor-I (IGF-I) was increased in LVRS-D4 compared with other emphysematous groups. Increased IGF-I immunoreactivity was localized to types IIA and I fibers. The abundance of the splice variant of IGF-I mRNA sensitive to muscle stretch (IGF-IEb) increased 3.2-fold in LVRS D-4 diaphragms, compared with emphysema-sham animals. The main form of IGF-I mRNA was unchanged. Marked force deficit was observed in the LVRS-D1 diaphragm, compared with emphysema-sham and emphysema (no surgery) animals. These data highlight a markedly compromised ventilatory pump acutely after LVRS. Acute fiber stretch predisposes to muscle fiber injury and may also be a necessary mechanotransductive stimulus for fiber remodeling as the diaphragm adapts to reduced lung volume.
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PMID:Short-term influences of lung volume reduction surgery on the diaphragm in emphysematous hamsters. 1520 Nov 33

Lung transplantation and lung volume reduction surgery have opened a new therapeutic era for patients with advanced emphysema. In addition to providing impressive clinical benefits, they have helped us better understand how the chest wall and respiratory muscles adapt to chronic hyperinflation. This article reviews the effects of these procedures on respiratory muscle and chest wall function. Inspiratory (including diaphragm) and expiratory muscle strength are often close to normal after unilateral and bilateral transplantation, although some patients have marked weakness. After bilateral transplantation for emphysema, graft volume is normal at full inflation but remains greater than normal at end expiration, which results from structural changes in the chest wall. In contrast, patients with unilateral transplantation have a reduction in graft volume at full inflation. The mediastinum is displaced toward the graft at end expiration, which reduces the surface area of the diaphragm on the transplanted side, and it moves toward the native lung during tidal and full inspiration and toward the graft during tidal and forced expiration. Lung volume reduction produces an increase in contractility, length and surface area of the diaphragm, and increases its contribution to tidal volume; at the same time, neural drive to the muscle and respiratory load are reduced, such that diaphragm neuromechanical coupling is improved. Diaphragm configuration and rib cage dimensions are only minimally affected by the procedure. Single-lung transplantation and lung volume reduction favorably impact on the disadvantageous size interaction by which the lungs are functionally restricted by the chest wall in emphysema.
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PMID:Effect of lung transplant and volume reduction surgery on respiratory muscle function. 1935 7