[Gas exchanges and COPD: on the interest of structure-function relationships].
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Humans↗
Biomedical subjects
V I Peinado
Publications and source records attributed to V I Peinado.
Pulmonary hypertension in chronic obstructive pulmonary disease.
Pulmonary hypertension is a common complication of chronic obstructive pulmonary disease (COPD). Its presence is associated with shorter survival and worse clinical evolution. In COPD, pulmonary hypertension tends to be of moderate severity and progresses slowly. However, transitory increases of pulmonary artery pressure may occur during exacerbations, exercise and sleep. Right ventricular function is only mildly impaired with preservation of the cardiac output. Structural and functional changes of pulmonary circulation are apparent at the initial stages of COPD. Recent investigations have shown endothelial dysfunction and changes in the expression of endothelium-derived mediators that regulate vascular tone and cell growth in the pulmonary arteries of patients with mild disease. Some of these changes are also present in smokers with normal lung function. Accordingly, it has been postulated that the initial event in the natural history of pulmonary hypertension in COPD could be the lesion of pulmonary endothelium by cigarette-smoke products. Long-term oxygen administration is the only treatment that slows down the progression of pulmonary hypertension in chronic obstructive pulmonary disease. Nevertheless, with this treatment pulmonary artery pressure rarely returns to normal values and the structural abnormalities of pulmonary vessels remain unaltered. Vasodilators are not recommended on the basis of their minimal clinical efficacy and because they impair pulmonary gas exchange. Recognition of the role of endothelial dysfunction in the physiopathology of pulmonary hypertension in chronic obstructive pulmonary disease opens new perspectives for the treatment of this complication.
Humans↗
Characterization of pulmonary vascular remodelling in smokers and patients with mild COPD.
Intimal enlargement of pulmonary arteries is an early change in chronic obstructive pulmonary disease (COPD). The cellular and extracellular components that are involved in this enlargement are unknown. The present study was designed to characterize the structural changes occurring in pulmonary muscular arteries in the initial disease stages. Lung specimens from patients with moderate COPD (n=8; forced expiratory volume in one second (FEV1), 66 +/- 10% predicted) and smokers without airflow obstruction (n=7; FEV1, 86 +/- 6% pred), were investigated by histochemistry to characterize extracellular matrix proteins and by immunohistochemistry to identify intrinsic cells of the vascular wall. In both COPD patients and smokers, the majority of cells present in the enlarged intimas were stained by specific smooth muscle cell (SMC) markers. No staining with endothelial or fibroblast markers was shown. A proportion of SMCs did not stain with desmin, suggesting cellular heterogeneity in this population. Elastin was the most abundant extracellular matrix protein and collagen was seen in a lower proportion. The amount of collagen was related to the intimal thickness (p<0.001). The findings demonstrated smooth muscle cell proliferation, as well as elastin and collagen deposition, in the thickened intimas of pulmonary arteries in moderate chronic obstructive pulmonary disease patients and smokers, suggesting that these abnormalities may originate at an early stage in cigarette smoke-induced respiratory disease.
Aged↗
Response to hypoxia of pulmonary arteries in chronic obstructive pulmonary disease: an in vitro study.
Patients with chronic obstructive pulmonary disease (COPD) show impaired hypoxic pulmonary vasoconstriction that might contribute to abnormal gas exchange and could be related to endothelial dysfunction in pulmonary arteries. The aim of the study was to investigate the response of PA to hypoxic stimulus in vitro in COPD, and the role of endothelium-derived nitric oxide (NO) in this response. The pulmonary arteries of 25 patients who underwent lung resection were studied. Patients were divided into controls, COPD+normoxaemia (COPDN) and COPD+ hypoxaemia (COPDH). Hypoxic vasoconstriction (HV) was evaluated before and after stimulation or inhibition of the endothelial release of NO, and in the presence of exogenous NO. Compared with the other groups, HV was reduced in COPDH. The magnitude of HV correlated with the oxygen tension in arterial blood. The hypoxic stimulus induced greater contraction after stimulating endothelial release of NO, whereas its inhibition practically abolished HV. Exogenous NO completely inhibited HV. Maximal relaxation induced by endothelium-dependent vasodilators correlated with the magnitude of HV. In conclusion, pulmonary arteries of patients with chronic obstructive pulmonary disease and hypoxaemia have an impaired response to hypoxic stimulus, and the endothelial release of nitric oxide modulates hypoxic vasoconstriction. The depressed response of pulmonary arteries to hypoxia may contribute to abnormal gas exchange in chronic obstructive pulmonary disease.
Aged↗
Reduced expression of endothelial nitric oxide synthase in pulmonary arteries of smokers.
Cigarette smoking has been associated with alterations in the structure and endothelial function of pulmonary arteries. Nitric oxide (NO) and endothelin-1 are endothelium-derived mediators with opposite effects on vascular tone and cell growth. To investigate whether cigarette smoking could induce changes in the synthesis of these mediators in pulmonary arteries, we compared the expression of both endothelial NO synthase (eNOS) and endothelin-1 in the lungs of smokers with that in nonsmokers. Lung tissue samples of 23 smokers and nine nonsmokers were studied. Expression of eNOS and endothelin-1 in pulmonary artery endothelium was evaluated by immunohistochemistry. In protein extracts of lung tissue, the content of eNOS protein was assessed by Western blot analysis and that of endothelin-1 by radioimmunoassay. The immunohistochemical expression of eNOS in arterial endothelium and the eNOS protein content in lung tissue were lower in the smokers than in the nonsmokers. No differences were shown in cell expression and protein content of endothelin-1 between both groups. We conclude that cigarette smoking is associated with reduced expression of eNOS in pulmonary arteries. The diminished synthesis of nitric oxide may contribute to the alterations in the structure and endothelial function of pulmonary vessels in cigarette-smoke-induced respiratory disease.
Aged↗
Medetomidine/tiletamine/zolazepam and xylazine/tiletamine/zolazepam combinations for immobilization of fallow deer (Cervus dama).
Eleven adult fallow deer (Cervus dama) were anesthetized using a mixture of xylazine/tiletamine/zolazepam, and 10 were anesthetized with a mixture of medetomidine/tiletamine/zolazepam. Anesthesia was adequate for capture in all instances, and minor surgical procedures were possible in seven of the animals treated with xylazine/tiletamine/zolazepam and in all of the animals treated with medetomidine/tiletamine/zolazepam. Blood gas, hematologic, serum biochemical, and cardiorespiratory parameters were measured during all immobilizations. The deer immobilized with xylazine/tiletamine/zolazepam had significantly higher lactate and cortisol values than the deer immobilized with the medetomidine combination. Although both methods were adequate for fallow deer, the medetomidine/tiletamine/zolazepam combination produced superior results.
Adrenergic alpha-Agonists↗
Pulmonary hypertension in COPD: old and new concepts.
Pulmonary hypertension is a common complication in chronic obstructive pulmonary disease (COPD). Its presence and severity is closely related to disease prognosis. Remodelling of pulmonary vessels is the principal causative factor of pulmonary hypertension in COPD. In advanced COPD, pulmonary vascular remodelling is related to the severity of arterial hypoxaemia. However, recent studies have shown that structural abnormalities and alterations of vascular function are also apparent in patients with mild COPD who do not have hypoxaemia and even in smokers with normal lung function. Pulmonary endothelium plays a crucial role in the regulation of vascular tone and cell growth of the vessel wall. Alterations of endothelial function in pulmonary arteries are apparent at the early stages of chronic obstructive pulmonary disease evolution. Potential mechanisms of endothelial damage at these initial stages include the effects of cigarette smoke components and inflammatory changes. The resultant alteration of pulmonary endothelium by these factors might predispose patients with mild chronic obstructive pulmonary disease to further vascular damage by additional factors, such as hypoxaemia, ultimately leading to pulmonary hypertension.
Animals↗
Basic hematological values in some wild ruminants in captivity.
Analyses of hematological parameters were carried out on eight axis deer (Cervus axis), 12 fallow deer (Cervus dama), 16 red deer (Cervus elaphus hippelaphus), three sambar (Cervus unicolor), nine Père David deer (Elaphurus davidianus), 20 European bison (Bison bonasus), seven nilgai (Boselaphus tragocamelus), eight mouflon (Ovis musimon), four white-bearded gnu (Connochaetes taurinus) and six barbary sheep (Ammotragus lervia). The following parameters were determined: packed cell volume, hemoglobin concentration, red blood cell number, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, leukocyte number and differential leukocyte count. Some degree of interspecific variability was found in the artiodactyls for these hematological parameters. An inverse relationship between mean corpuscular volume and red blood cell number is described, and specific values for these parameters are given for the four subfamilies.
Animals↗
Inflammatory reaction in pulmonary muscular arteries of patients with mild chronic obstructive pulmonary disease.
Endothelial dysfunction and intimal thickening have been shown in pulmonary arteries (PA) of patients with mild chronic obstructive pulmonary disease (COPD). To investigate whether an inflammatory process related to tobacco smoking might be involved in the development of pulmonary vascular abnormalities in COPD, we characterized the inflammatory cell infiltrate and the endothelium-dependent relaxation in PA of 39 patients who underwent lung resection, divided into three groups: "nonsmokers" (n = 7); "smokers," with normal lung function (n = 12); and "COPD" (n = 20). Endothelium-dependent relaxation was assessed in vitro by exposing PA rings to adenosine diphosphate (ADP). Inflammatory cell types were identified by immunohistochemistry. PA of COPD patients developed lower relaxation in response to ADP than nonsmokers and smokers. The number of inflammatory cells was increased in PA of COPD compared with the other two groups. This cell infiltrate was largely constituted by T lymphocytes. The CD8(+) T-cell subset was increased in both smokers and COPD compared with nonsmokers, yielding a reduction of the CD4(+)/CD8(+) ratio. The intensity of the inflammatory infiltrate correlated with both the endothelium-dependent relaxation and the intimal thickness. We conclude that cigarette smoking induces a CD8(+) T-lymphocyte infiltrate in PA, which is associated with the impairment of the vessel's structure and function, suggesting the potential involvement of an inflammatory process in the pathogenesis of pulmonary vascular abnormalities in the early stage of COPD.
Aged↗
Endothelial dysfunction in pulmonary arteries of patients with mild COPD.
To investigate whether endothelial dysfunction of pulmonary arteries (PA) is present in patients with mild chronic obstructive pulmonary disease (COPD) and to what extent it is related to the morphological abnormalities of PA, we studied 41 patients who underwent lung resection. Patients were divided into the following groups: nonsmokers (n = 7), smokers with normal lung function (n = 13), and COPD (n = 21). Endothelium-dependent relaxation mediated by nitric oxide was evaluated in vitro in PA rings exposed to cumulative concentrations of acetylcholine (ACh) and ADP. Structural abnormalities of PA were assessed morphometrically. PA of COPD patients developed lower maximal relaxation in response to ADP than both nonsmokers and smokers (P < 0.05 each) and a trend to reduced relaxation in response to ACh (P = 0.08). Maximal relaxation to ADP correlated with the degree of airflow obstruction (r = 0.48, P < 0. 01). Morphometrical analysis of PA revealed thicker intimas, especially in small arteries, in both smokers and COPD compared with nonsmokers (P < 0.05 each). We conclude that endothelial dysfunction of PA is already present in patients with mild COPD. In these patients, as well as in smokers with normal lung function, small arteries show thickened intimas, suggesting that tobacco consumption may play a critical role in the pathogenesis of pulmonary vascular abnormalities in COPD.
Acetylcholine↗
Effect of a platelet-activating factor (PAF) antagonist, SR 27417A, on PAF-induced gas exchange abnormalities in mild asthma.
Inhaled platelet-activating factor (PAF), both in normals and in asthmatic patients, provokes transient systemic effects, neutropenia, bronchoconstriction and arterial oxygenation abnormalities similar to those shown in spontaneous exacerbations of asthma. To investigate the efficacy of a new PAF-receptor antagonist, SR 27417A, on all these changes after PAF challenge, 12 nonsmoking patients (four females and eight males) (mean+/-SEM) age 24+/-1 yrs with mild asthma (forced expiratory volume in one second (FEV1) 93+/-3% predicted) were studied in a double-blind, placebo-controlled, cross-over fashion 2 weeks apart. PAF aerosol challenge (18 microg) was carried out 3 h after oral administration of either SR 27417A (20 mg) or placebo. Respiratory system resistance (Rrs) and arterial blood gases and neutrophil cell counts were measured at baseline, before compound/placebo administration, and at 5, 15 and 45 min after PAF. Compared to vehicle, SR 27417A brought about moderate attenuation of PAF-induced neutropenia at 5 min (by 140%; p<0.025), and rebound neutrophilia at 15 and 45 min (p<0.025), increases of Rrs (by 90-65%) (p<0.01) and of alveolar-arterial pressure difference for oxygen (PA-a,O2) at 5 min (by 68%) and 15 min (by 63%), and decreases of arterial oxygen tension (Pa,O2) at 5 min (by 57%; p<0.025, each). Furthermore, systemic effects and platelet aggregation tests (p<0.001) were abolished after the administration of the compound. We conclude that SR 27417A is effective in inhibiting systemic, cellular and pulmonary effects after platelet-activating factor challenge in patients with mild bronchial asthma.
Adult↗
Hematology and serum chemistry in the white-crowned mangabey (Cercocebus torquatus lunulatus) and in the mandrill (Mandrillus sphinx).
Reference values of some hematologic and plasma chemical parameters were established in two species of clinically normal Cercopithecidae. The following variables were studied in seven mandrills (Mandrillus sphinx) and nine white-crowned mangabeys (Cercocebus torquatus lunulatus): hematocrit, hemoglobin concentration, erythrocyte and leucocyte counts, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, glucose, urea, uric acid, cholesterol, creatinine, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatinine phosphokinase, lactic dehydrogenase, gamma glutamyl transpeptidase, total serum proteins, albumin, globulins, albumin-globulin ratio, sodium, potassium, calcium, magnesium, total phosphorus, chloride, and serum osmolality. Few differences were observed when compared with human hematological data and with other species of Cercopithecidae Primates.
Animals↗
Effect of captivity on the blood composition of Spanish ibex (Capra pyrenaica hispanica).
Blood analyses of seven free-ranging Spanish ibex (Capra pyrenaica hispanica) captured from the wild and then held in captivity were used to determine the physiological changes in some haematological parameters and serum chemistry values during captivity. The captive animals had a higher haematocrit and haemoglobin concentration and larger numbers of erythrocytes than the same animals when they were captured. In addition, the absolute numbers of leucocytes and lymphocytes decreased progressively during captivity. Significant differences were found for some of the biochemical variables between the captive ibex and free-ranging animals.
Animals↗
Factors influencing acid-base status during acute severe hypothermia in unanesthetized rats.
Blood acid-base changes were studied during acute hypothermia (4-6 h) induced by cold exposure in the unanesthetized rat. Stewart's quantitative analysis was applied as a complementary approach to determine the relative contributions of several non-respiratory components to the arterial acid-base response. Acute decrease in body temperature (TB) lowered PaCO2 (32.5 to 14.5 mmHg) and [HCO3-]a(24.20 mEq/L to 17.56 mEq/L), increased pHa (7.481 to 7.608) and diminished the [OH-]/[H+] ratio, but had no significant effect on [SID] or [Atot], although both total phosphorus [PT] and inorganic phosphate [Pi] increased. The acid-base changes found were intermediate between those predicted by alpha-stat and pH-stat hypotheses. Deviation from the regulative alpha-imidazole strategy was more apparent in the plasma than in the intraerythrocyte compartment. We conclude that blood pH changes observed were mainly caused by increased relative ventilation (lung ventilation per unit of CO2 removed) and by resulting changes in PCO2, with a minor metabolic component but without significant contribution from ionic shifts or changes in plasma protein concentration.
Acid-Base Imbalance↗
Haematology of Spanish ibex (Capra pyrenaica hispanica) restrained by physical or chemical means.
Reference values for some haematological and plasma biochemical constituents were established in Spanish ibex (Capra pyrenaica hispanica) restrained either physically or chemically with tiletamine-zolazepam. The following variables were studied: haematocrit, haemoglobin concentration, total erythrocyte and leucocyte counts, haematological indices, erythrocyte dimensions, differential count of leucocytes, glucose, urea, uric acid, cholesterol, triglycerides, creatinine, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatinine phosphokinase, lactic dehydrogenase, gamma-glutamyl transpeptidase, total plasma protein, albumin, globulins, albumin-globulin ratio, sodium, potassium, calcium, magnesium, total phosphorus, chloride and osmolality. No haematological data have been published before but the values observed were in the general range of other artiodactyls, with the exception of the number and size of the erythrocytes which were respectively larger and smaller than in most other ruminants. Significant differences were found for a number of the variables between the values recorded in physically restrained animals and the values recorded in anaesthetised animals; they included the number of erythrocytes and related parameters, the plasma proteins and some inorganic ions.
Animals↗
Erythrocyte osmotic resistance during acute hypothermia in awake unrestrained rats.
Erythrocyte osmotic fragility and plasma ionic composition were studied in rats subjected to acute hypothermia. A decrease in osmotic fragility and a significant increase in plasma magnesium and total phosphorus were observed in blood from hypothermic rats in relation to control. A decrease in erythrocyte osmotic fragility from hypothermic animals was observed when the test was performed at 37 degrees C, whereas osmotic fragility was unaltered if the test was carried out at body temperature. This could be interpreted as an adaptative response to counteract the opposite effect on erythrocyte osmotic fragility observed at low temperature 'in vitro'.
Animals↗
Hematologic and plasma chemistry values in captive psittacine birds.
Reference values for some hematologic parameters in 19 species and plasma chemical values in 11 species of Psittacine birds, including cockatoos, parrots, amazons, macaws, conures, and lories, were established for use in veterinary medicine. The following parameters were studied: hematocrit, hemoglobin concentration, erythrocyte number, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, erythrocyte dimensions, leukocyte number and differential leukocyte count, glucose, urea, uric acid, cholesterol, triglycerides, creatinine, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatinine phosphokinase, lactic dehydrogenase, gamma glutamyl transpeptidase, total plasma protein, albumin, globulins, albumin-globulin ratio, sodium, potassium, calcium, magnesium, total phosphorus, chloride, and osmolality. Hematologically, the Psittacine is a very homogeneous avian group, with small differences between species. They are, however, different from other groups of birds.
Animals↗