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Biomedical subjects

G Scano

Publications and source records attributed to G Scano.

124 records · Page 7Linked to original sources
PubMed1984

Comparative effects of SCH 1000 and fenoterol after histamine-induced bronchoconstriction in asymptomatic asthmatics.

In 16 asymptomatic asthmatics a functional study was carried out under controlled conditions during histamine bronchial provocation test (HBPT) and after bronchodilation test with either SCH 1000 or fenoterol by evaluating both SRAW and the slope of the alveolar plateau of nitrogen washout curve (N2 ph III). During HBPT, 9 of 16 subjects showed a central response (increase in RAW and SRAW only), whereas in the remaining 7 subjects histamine induced a mixed response due to an increase in both SRAW and N2 ph III. No differences between the two groups were observed in age and functional data during controlled conditions. Doses of delivered histamine were not significantly different. In 5 of 9 central responders to HBPT, SCH 1000 induced a decrease in SRAW only, whereas in 3 of the remaining 4 fenoterol caused both central and peripheral bronchodilation (decrease in both SRAW and N2 ph III). All mixed responders to HBPT showed a mixed bronchodilation during SCH 1000 (three subjects) or fenoterol (the remaining four). These data seem to indicate that the mechanism of bronchodilation induced by SCH 1000 is related to that of histamine-induced bronchoconstriction. Moreover, bronchodilation due to fenoterol could be related to a vagal modulation or be a systemic direct effect.

Adult↗
PubMed1983

Effect of fenoterol on small airways and regional lung function in asymptomatic asthma.

Lung function tests for small airways were performed before and after inhalation of fenoterol by 11 young asymptomatic asthmatics and in 8 control subjects. In the asthmatics, minimal impairment in the tests was found except for increased expansion of the lower part of the lung (133Xe regional lung volumes) and an "abnormal" distribution pattern of a bolus of Xe inhaled from the residual volume. This suggests enhanced airway closure, especially in the lower area of the lung. Usual therapeutic doses of fenoterol (0.4 to 0.6 mg in puffs) could not correct these abnormalities, but 1.2 mg given to 2 patients resulted in changes similar to those observed in normals. The results suggest that small airway impairment in asymptomatic asthmatics is not only related to enhanced bronchomotor tone, but also to anatomical changes located especially at the base of the lung.

Adult↗
PubMed1983

Effects of steroid therapy on pulmonary involvement in sarcoidosis.

In eleven patients with stage II-III pulmonary sarcoidosis as assessed by mediastinoscopy or open lung biopsy, we carried out a functional study by evaluating static and dynamic pulmonary volumes, diffusing lung properties (TLCO, KCO), and mechanical properties: resistance of the airway, flow-volume curve, pressure-volume curve, flow-pressure curve, and dynamic compliance. In 7 of 11 patients a clinical and functional follow-up during steroid treatment over a period of 5 months to 3 years was also performed. Before treatment diffusing properties were in the normal range in 6 of 11 subjects, reduced in 4, and increased in 1. Elastic properties studied in 8 patients were in the normal range, whereas peripheral airway involvement was noted in 4 nonsmokers. During the follow-up the changes noted in diffusing lung properties on the whole parallelled the clinical and radiologic improvement or relapses after cessation of therapy. In contrast, no changes in elastic properties or lung volume were noted. We concluded that steroid treatment seems to improve parenchymal lung involvement in most cases as shown by the increase in diffusing lung properties.

Adult↗
PubMed1982

Site of action of inhaled histamine in asymptomatic asthmatic patients.

Histamine inhalation provocation-tests were performed in twenty-two young asthmatics with normal lung-function tests with progressive, increasing doses of a pressurized aerosol of histamine phosphate. Airway resistances (Raw) and N2 washout-curves were recorded. Two different types of response have been observed: (1) in thirteen cases, there was an increase of both Raw and the N2 phase III slope; and (2) in eight cases, there was only an increase in Raw (in one subject there was an increase in the N2 phase III slope only). Comparing the two groups of patients there was no difference in the inhalation procedure, the dose of histamine delivered or the smoking habits and lung-function data, except a slightly higher residual volume/total lung capacity (RV/TLC) ratio in the first group. The histamine-induced changes could not be related to any of the control lung-function data. We conclude that histamine inhalation may induce either peripheral bronchoconstriction only, or central bronchoconstriction with or without peripheral bronchoconstriction. A local and/or peripheral vagal-mediated bronchoconstrictor effect could account for the different site of airway response.

Adult↗
PubMed1982

Lung mechanics after aerosol and intravenous SCH 1000 in normal humans.

A functional study was carried out in six normal subjects before and after 0.5 mg of an intravenous atropine congener (SCH 1000) by evaluating the following parameters: static pulmonary volumes, resistance of the airways (Raw), N2 closing volume/vital capacity ratio, maximal expiratory flow volume, and the pressure-volume curves. From these curves we calculated the maximum flow-static recoil curves and the resistance of the airways upstream from the equal pressure point (Rus). On the following day four of six subjects inhaled 6 puffs (240 micrograms) of aerosolized SCH 1000 and the same parameters were evaluated. Both procedures caused a significant increase in maximum expiratory flow and a decrease in Raw. However, only intravenous SCH 1000 caused an increase in lung compliance and a decrease in Rus. When compared with previous data, our results show no dose-response effect on the atropine-induced modifications of pulmonary mechanics, and thus confirm the exclusive central bronchodilator effect of the aerosolized SCH 1000.

Adult↗
PubMed1982

Effect of oxygen on breathing during exercise in patients with chronic obstructive lung disease.

In 10 exercising patients with chronic obstructive lung disease (COLD) we measured ventilation (VE), end-tidal CO2 (PETCO2), mean inspiratory flow (VT/TI), the ratio of inspiratory time to total time for one cycle (TI/TTOT), and occlusion pressure at 0.1 s measured at the mouth (P O.1), when they breathed room air and 100% oxygen. Oxygen breathing increased the maximal work load achieved. Furthermore, at the same exercise load, P O.1, VT/TI, VE, heart rate, respiratory frequency (f) decreased significantly in hyperoxia as compared with normoxia. Thoraco-pulmonary impedance assessed by P 0.1/VE and P 0.1/(VT/TI) ratios showed a slight but significant decrease to the respiratory centre. Thus in exercising patients affected by COLD, hyperoxia not only decreases the chemical afferent drive but also may slightly reduce the afferent mechanical drive to the respiratory centre. The decrease in the thoraco-pulmonary impedance may be explained either by an increase in efficiency of the respiratory muscles and/or a decrease in airway resistance.

Adult↗
PubMed1981

Hemodynamic characteristics in chronic obstructive lung disease as related to cardiac size.

The hemodynamic adaptation during exercise was evaluated in 19 patients suffering from chronic obstructive lung disease. They were divided into two groups according to cardiac size on the X-ray (group 1, small; group 2, normal). A small cardio-thoracic ratio could be correlated with 'emphysema' assessed on the basis of hyperinflation and a low transfer test for CO. No clear-cut difference could be found between the two groups concerning the hemodynamic data at rest or during exercise. However, for all subjects, the cardiac output was found to be slightly related to the cardiac size (smaller cardiac output for smaller cardiac size). During exercise, a low cardiac output was characterized by a low oxygen transport and a high level of lactate. From this, it is suggested that a small cardiac size, a classical feature of hyperinflation and emphysema, may lead to a low cardiac output. The explanation for these results is speculative, but variable hemodynamic profiles in chronic obstructive lung disease with or without hyperinflation may be related to the morphology of the cardiac chambers and to variable intrathoracic pressure regimes during respiration.

Adult↗
PubMed1981

Functional evaluation of tracheal stenosis before and after surgical management.

14 patients affected by tracheal stenosis resulting from assisted ventilation underwent a tracheal resection (n = 12) or dilatation (n = 2). Lung function tests were performed before and after surgical treatment. Prior to surgery, we observed a significant increase in airway resistance (Raw) in all subjects and a negative exponential relationship between Raw and FEV1/VC. Expiratory flows were also reduced with an increase in FEV1/PEFR ratios. After surgical correction of the stenosis, Raw normalized in 10 out of 14 subjects. The observed changes were more significant than for the other functional tests. After surgery, the patient's follow-up with Raw allowed the diagnosis of recurrent stenosis in 4 subjects lacking significant clinical symptoms. We conclude that measurement of Raw helps the clinical diagnosis and the appreciation of the possible changes in airway permeability after the surgical procedure.

Forced Expiratory Volume↗
PubMedDate not supplied

Respiratory muscle overloading and dyspnoea during bronchoconstriction in asthma: protective effects of fenoterol.

Whether, and to what extent, beta 2-agonists protect against respiratory muscle overloading and breathlessness during bronchoconstriction remains to be defined in patients with asthma. In a double blind placebo-controlled study, 100 micrograms of fenoterol were administered to six stable asthmatics before a bronchial provocation test, performed by inhaling doubling concentrations of histamine from a Devilbiss 646 nebulizer. We recorded breathing pattern (tidal volume VT, inspiratory time TI, total time of the respiratory cycle TTOT), inspiratory capacity (IC), dynamic pleural pressure swing (Pplsw), total lung resistance (RL) and FEV1. VT was expressed both in actual values and as % of IC. Changes in VT (%IC) during histamine inhalation reflected changes in dynamic end-inspiratory lung volume (EILV). Pplsw was expressed as % of maximal (the most negative in sign) pleural pressure, obtained under control conditions during a sniff manoeuvre (Pplsn). Pplsw (%Pplsn) is an index of inspiratory muscle effort. The test ended when the concentration of histamine which caused a decrease in FEV1 of > or = 40% post-saline was reached. Dyspnoea rating was scored by a modified Borg scale. At the ultimate degree of bronchoconstriction (UDB) with histamine: (i) decrease in FEV1 was similar after placebo and fenoterol, while increase in RL was lower after fenoterol (P < 0.005); (ii) VT(%IC) increased less after fenoterol (P < 0.027); (iii) increases in Pplsw (%Pplsn) was lower after fenoterol (P < 0.001); (iv) delta Borg (from saline) was lower (P < 0.01) after fenoterol; (v) differences in delta Borg, from placebo to fenoterol, related to concurrent changes in VT(%IC) (r2 = 0.67). In conclusion, at UDB 100 micrograms of fenoterol produced a beneficial effect on the degree of inspiratory muscle loading and breathlessness, an effect greater than it would be expected from measuring FEV1 alone.

Adrenergic beta-Agonists↗
PubMedDate not supplied

Cardiopulmonary adaptation to exercise in coal miners.

Twenty-six coal miners, without associated functional chronic obstructive lung disease (COLD), assessed by normal airway resistance, were divided into three groups: (1) Group C, normal X-ray; (2) Group S1, micronodular silicosis; and (3) Group S2, complicated silicosis. All subjects were evaluated while at rest and during exercise. Significant lung volume reduction was observed in the S2 Group only. Blood gases, pulmonary pressure, and cardiac output were found to be within the normal range for all three groups when at rest. The pulmonary pressure and pulmonary vascular resistance were higher, however, for the S1 and S2 Groups when compared to the C Group. During exercise, pulmonary hypertension was observed in 50% of teh patients with complicated silicosis. When all data (N = 26) were included, the high values for pulmonary pressure and pulmonary vascular resistance correlated well with the loss in vital capacity (VC) and the decrease in forced expiratory volume in 1 sec (FEV 1.0). From the initial 26 patients, 19 were selected on the basis of their normal airway resistance and FEV 1.0/VC ratio. This selection did not alter the differences noted for the pulmonary pressure and total pulmonary vascular resistance, which previously existed between the groups, even though the correlations were not statistically significant. We conclude that silicosis without associated COLD leads to mineral hemodynamic impairment at rest and during exercise, and that airway resistance does not detect impairment of flow as effectively as FEV 1.0 reduction. The increased pulmonary vascular resistance observed, especially in complicated silicosis, may be best explained by the loss of lung parenchyma and possible impairment of small airways.

Adult↗
PubMedDate not supplied

COL1A2 (type I collagen) polymorphisms in the Colorado Indians of Ecuador.

BACKGROUND: EcoRI, MspI and RsaI restriction fragment length polymorphisms (RFLPs) of the COL1A2 (type I collagen) gene are proving to be extremely informative markers for describing human populations; therefore they hold considerable potential for anthropogenetic research. AIM: The objective of this study was to characterize at the DNA level the Colorado Indians from Ecuador, for whom only blood group frequency information is available, and to investigate their relationships with the Cayapa-another Ecuadoran Native American group belonging to the same linguistic affiliation-and other world populations. SUBJECTS AND METHODS: Colorado Indians (n = 80) were analysed for the three anthropologically informative RFLPs of the COL1A2 gene. To better define the genetic relationship between this group and other populations, principal component analysis (PCA) was performed and genetic distances were estimated. Population genetic structure was tested through analysis of molecular variance (AMOVA) by comparing haplotype frequencies. RESULTS: COL1A2 allele and haplotype frequencies showed a certain degree of heterogeneity between the two Chibchan populations of Ecuador. The AMOVA test detected a significant level of differentiation (Fst = 0.034, p = 0.0049) between Colorado and Cayapa Indians. PC and genetic distance analyses showed a clear-cut separation between African and non-African populations; within the latter, the two Native American groups were differentiated from each other. CONCLUSIONS: The present findings suggest the presence of a low level of genetic relatedness between the Colorado and the Cayapa, despite their supposed common ethnogenesis. This confirms what has been inferred from other genetic data about the high degree of heterogeneity among Native Americans, even within the same linguistic branch, thus supporting the existence of genetic sub-structure within the central and southern American populations.

Alleles↗
PubMedDate not supplied

One year follow-up of a HIV seropositive jail population.

A jail population has been followed for one year to study the risk of HIV-seroconversion. Our data show that life in jail is not necessarily a condition for HIV spread. In fact no variation of seropositivity distribution has been found.

Comorbidity↗
PubMedDate not supplied

Control of breathing in normal subjects and in patients with chronic airflow obstruction.

In order to assess ventilatory control in patients with chronic airflow obstruction (CAO), the present study was carried out in nine patients with chronic obstructive pulmonary disease (COPD), eight asthmatics and nine normal subjects. We analysed the components of the respiratory control system at three levels: neural, assessed by diaphragmatic electromyography (EMGd), muscular, assessed by mouth occlusion pressure (P0.1), and ventilatory, assessed by mean inspiratory flow (VT/TI). EMGd was recorded by surface electrodes. During a CO2 rebreathing test, patients showed a normal or greater EMGd response slope (EMGdS), while for a given degree of EMGdS, P0.1 response slope (P0.1S) was found to be significantly reduced; in contrast, for a given degree of P0.1S, VT/TI response slope (VT/TIS) was found to be significantly reduced in COPD patients only. These data show that, compared to normal subjects, patients with CAO have a normal or increased neural component of the respiratory activity (EMGdS) and a relatively lower neuromuscular coupling (P0.1S/EMGdS). Probably due to different parenchymal and airway involvement, musculoventilatory transfer (VT/TIS/P0.1S) was found to be reduced in COPD patients but not in asthmatics. A complementary study, showing a good agreement between surface and oesophageal EMGd seems to confirm that surface EMGd is a useful and promising tool for clinical investigation.

Asthma↗
PubMedDate not supplied

Respiratory drive and ventilatory pattern during exercise in interstitial lung disease.

Ventilation was analysed during a maximal and progressive exercise in 12 patients suffering from interstitial lung disease (ILD) and in 15 healthy subjects. "Rapid shallowing breathing" pattern was observed in patients with ILD. Both normals and patients showed a linear relationship between VE, VT/TI (mean inspiratory flow) and VCO2. The relationship between P0.1, the occlusion pressure at 0.1 S, and VCO2 exponential in both groups and significantly steeper in patients with ILD. P0.1/VE and P0.1/(VT/TI) ratios, indexes of thoracopulmonary impedance, and P0.1/VCO2 ratio, an index of respiratory drive per unit of CO2 output, were all inversely correlated in patients with VC% (vital capacity) and CLstat (static compliance). These results strongly suggest that in patients suffering from ILD the higher respiratory drive observed during exercise could be attributed to increased afferent reflexes originating from the lung and/or chest wall.

Adult↗