RESUMEN
This study assessed whether a microswitch duster with favorite stimulation could help a 9.1-yr.-old child with multiple disabilities increase arm-lifting responses without dystonic, sideways head tilting. The microswitch cluster involved two microswitches, one at the child's arm to monitor the lifting response, and the other at the child's head to monitor whether it was tilted during arm lifting. Analysis showed that the percentage of arm-lifting responses occurring without head tilting increased most visibly when favorite stimulation focused on those (appropriate) responses.
Asunto(s)
Brazo/fisiología , Niños con Discapacidad/rehabilitación , Distonía/prevención & control , Cabeza/fisiología , Movimiento/fisiología , Dispositivos de Autoayuda/estadística & datos numéricos , Transductores/estadística & datos numéricos , Fenómenos Biomecánicos/instrumentación , Fenómenos Biomecánicos/métodos , Niño , Distonía/fisiopatología , Lateralidad Funcional/fisiología , Cabeza/fisiopatología , Humanos , MasculinoRESUMEN
We adapted a grid into a microswitch for the hand movements of a girl with profound multiple disabilities who lay on her back. The grid, suspended above the girl's face, was equipped with two mercury devices, i.e., small sealed ampoules containing a mercury drop and ending with conductive leads. A lateral or forward movement of the grid would make the mercury drop of at least one device slide to the conductive leads and activate the device. During the intervention, activations of the devices, i.e., microswitch activations, produced the occurrence of favorite stimuli. Analysis showed that the girl increased the frequency of hand movements and microswitch activations during the intervention phases compared to the baseline phases (when the favorite stimuli were not available). The increase was retained at a 1-mo. postintervention check.
Asunto(s)
Anomalías Múltiples/fisiopatología , Equipos de Comunicación para Personas con Discapacidad , Niños con Discapacidad/rehabilitación , Mano/fisiología , Movimiento/fisiología , Dispositivos de Autoayuda , Niño , Femenino , Humanos , Índice de Severidad de la EnfermedadRESUMEN
BACKGROUND: The lowering of high serum cholesterol levels may be associated with increased non-cardiac mortality due to behavioral changes, although such endpoints are likely rare. OBJECTIVE: This current study sought to determine if hormonal changes accompany pharmacologically induced decreases in serum cholesterol levels. METHOD: Cholesterol, dopamine, homovanillic acid (HVA), serotonin, 5-HIAA, testosterone, cortisol and pregnenolone were measured at baseline and after 4 weeks of treatment. RESULTS: Subjects' cholesterol levels significantly declined within 4 weeks. Concomitant significant increase in dopamine and HVA were noted. CONCLUSION: Although this study is limited in size, it raises the possibility that cholesterol-lowering drug treatment is associated with hormonal perturbations.
Asunto(s)
Ácidos Heptanoicos/efectos adversos , Hormonas/sangre , Inhibidores de Hidroximetilglutaril-CoA Reductasas/efectos adversos , Hiperlipidemias/tratamiento farmacológico , Lovastatina/efectos adversos , Pirroles/efectos adversos , Adulto , Anciano , Anciano de 80 o más Años , Atorvastatina , Colesterol/sangre , Método Doble Ciego , Femenino , Ácidos Heptanoicos/uso terapéutico , Hormonas/agonistas , Humanos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Hiperlipidemias/sangre , Lovastatina/uso terapéutico , Masculino , Persona de Mediana Edad , Pirroles/uso terapéuticoRESUMEN
To test the hypothesis that in chronic obstructive pulmonary disease (COPD) patients the ventilatory and metabolic requirements during cycling and walking exercise are different, paralleling the level of breathlessness, we studied nine patients with moderate to severe, stable COPD. Each subject underwent two exercise protocols: a 1-min incremental cycle ergometer exercise (C) and a "shuttle" walking test (W). Oxygen uptake (VO(2)), CO(2) output (VCO(2)), minute ventilation (VE), and heart rate (HR) were measured with a portable telemetric system. Venous blood lactates were monitored. Measurements of arterial blood gases and pH were obtained in seven patients. Physiological dead space-tidal volume ratio (VD/VT) was computed. At peak exercise, W vs. C VO(2), VE, and HR values were similar, whereas VCO(2) (848 +/- 69 vs. 1,225 +/- 45 ml/min; P < 0. 001) and lactate (1.5 +/- 0.2 vs. 4.1 +/- 0.2 meq/l; P < 0.001) were lower, DeltaVE/DeltaVCO(2) (35.7 +/- 1.7 vs. 25.9 +/- 1.3; P < 0. 001) and DeltaHR/DeltaVO(2) values (51 +/- 3 vs. 40 +/- 4; P < 0.05) were significantly higher. Analyses of arterial blood gases at peak exercise revealed higher VD/VT and lower arterial partial pressure of oxygen values for W compared with C. In COPD, reduced walking capacity is associated with an excessively high ventilatory demand. Decreased pulmonary gas exchange efficiency and arterial hypoxemia are likely to be responsible for the observed findings.
Asunto(s)
Adaptación Fisiológica , Ciclismo , Enfermedades Pulmonares Obstructivas/fisiopatología , Respiración , Caminata , Anciano , Arterias , Gases/sangre , Humanos , Ácido Láctico/sangre , Enfermedades Pulmonares Obstructivas/sangre , Masculino , Persona de Mediana Edad , Intercambio Gaseoso Pulmonar , Espacio Muerto Respiratorio , Volumen de Ventilación PulmonarRESUMEN
OBJECTIVE: Exercise tolerance is often reduced in patients with systemic lupus erythematosus (SLE). Mechanisms have been proposed but the underlying causes have not yet been elucidated. The study of pulmonary gas exchange during exercise may be helpful in revealing circulatory, ventilatory, and metabolic abnormalities. We hypothesized that in SLE, exercise aerobic capacity would be reduced due to chronic inactivity and poor muscle energetics. METHODS: Thirteen women with SLE and low disease activity were studied; 5 age matched subjects served as controls. Clinical examination, chest radiography, electrocardiogram, and pulmonary function test were all normal. Subjects underwent 1 min incremental cycle ergometer exercise to exhaustion. Oxygen uptake (VO2), CO2 output (VCO2), minute ventilation (VE), heart rate (HR), and arterial O2 saturation were monitored. Anaerobic threshold (AT), VO2/HR, deltaVO2/deltaWatt, respiratory rate (RR), Ti/Ttot, VE/VCO2, and breathing reserve (BR) were computed. RESULTS: At rest, patients exhibited high VE, respiratory alkalosis, and a wide alveolar-arterial O2 gradient [(A - a)O2] during 50% O2 breathing. Other indexes of respiratory function were within the normal range. In the 6 patients with SLE where pulmonary artery systolic pressure at Doppler echocardiography was measurable, mean level was in the upper limits of normal. During exercise, maximal aerobic capacity was reduced in all patients (VO2 peak, 1098+/-74 vs. 2150+/-160 ml/min, p<0.01; AT, 36 +/-3 vs. 48+/-3% predicted VO2 max, p<0.05). Ventilation adjusted for the metabolic demand (VE/VCO2 at AT) was increased (31+/-1 vs. 24+/-1; p<0.05). A normal breathing pattern was observed during all tests. No patient stopped exercising because of ventilatory limitation (i.e., they had normal breathing reserve). CONCLUSION: Reduced muscle aerobic capacity is common in SLE and is most likely because of peripheral muscle deconditioning. Increased ventilatory demand, secondary to diffuse interstitial lung disease, is not a significant contributor to the reduction in exercise tolerance.
Asunto(s)
Tolerancia al Ejercicio , Lupus Eritematoso Sistémico/fisiopatología , Intercambio Gaseoso Pulmonar , Adulto , Umbral Anaerobio , Prueba de Esfuerzo , Femenino , Humanos , Músculo Esquelético/fisiología , Oxígeno/farmacocinéticaRESUMEN
BACKGROUND: Hypercortisolemia is frequently observed in major depression but its pathophysiologic significance is unknown. In patients in whom hypercortisolism contributes to depressive symptomatology, antiglucocorticoid agents should have antidepressant effects. METHODS: Twenty medication-free depressed patients (eight of whom were hypercortisolemic and twelve of whom were not) received either the cortisol biosynthesis inhibitor, ketoconazole (400-800 mg/d p.o.) or placebo for 4 weeks in a double-blind manner, and behavioral ratings were performed weekly. RESULTS: Ketoconazole, compared to placebo, was associated with improvements in depression ratings in the hypercortisolemic, but not in the non-hypercortisolemic patients. The hormonal changes seen (decreased dehydroepiandrosterone and testosterone levels and increased pregnenolone and pregnenolone-sulfate levels) are consistent with enzymatic blockade of C17,20-lyase, 11-hydroxylase, and 17-hydroxylase. Ketoconazole was generally well tolerated with no occurrence of significant side effects or laboratory abnormalities. CONCLUSIONS: This small-scale double-blind study suggests that antiglucocorticoids have antidepressant activity in hypercortisolemic depressed patients. The data are consistent with a causal role of adrenocortical dysfunction in some depressed patients and suggest the need for larger-scale trials.
Asunto(s)
Trastorno Depresivo Mayor/tratamiento farmacológico , Cetoconazol/uso terapéutico , Adulto , Trastorno Depresivo Mayor/sangre , Trastorno Depresivo Mayor/diagnóstico , Método Doble Ciego , Femenino , Glucocorticoides/antagonistas & inhibidores , Humanos , Hidrocortisona/sangre , Masculino , Persona de Mediana Edad , Proyectos Piloto , Escalas de Valoración Psiquiátrica , Índice de Severidad de la EnfermedadRESUMEN
BACKGROUND: Estrogen replacement therapy (ERT) may delay dementia-related cognitive decline in post-menopausal women, but few studies have longitudinally examined this relationship and none has controlled for baseline functioning or concurrent medication. METHODS: We report the results of a 1-year retrospective longitudinal study examining cognitive functioning in female estrogen and nonestrogen users (n = 3128) who presented to the state of California memory disorder clinics in a naturalistic multisite study of senile dementia, Alzheimer's type (SDAT), and other cognitive impairments. RESULTS: At baseline, estrogen users had significantly lower rates of SDAT diagnoses (possible and probable) than nonestrogen users, and significantly higher rates of the lesser diagnoses of "cognitive impairment" and "no dementia." ERT was significantly associated with higher cognitive functioning at baseline and at 1 year follow-up (n = 358). Nonestrogen users deteriorated significantly from baseline to follow-up; estrogen users did not. Results were similar in groups matched on baseline Blessed-Roth Dementia Rating Scale (BRDRS) ratings (n = 32) and in a variety of subpopulations. CONCLUSIONS: These findings are consistent with estrogen acting as a protective factor against cognitive deterioration in post-menopausal women with SDAT and other cognitive impairments, and may suggest an increased effect in earlier stages of cognitive impairment.
Asunto(s)
Trastornos del Conocimiento/etiología , Trastornos del Conocimiento/prevención & control , Cognición/efectos de los fármacos , Estradiol/farmacología , Terapia de Reemplazo de Hormonas/métodos , Trastornos de la Memoria/etiología , Trastornos de la Memoria/prevención & control , Memoria/efectos de los fármacos , Posmenopausia/psicología , Anciano , Trastornos del Conocimiento/diagnóstico , Femenino , Estudios de Seguimiento , Humanos , Trastornos de la Memoria/diagnóstico , Persona de Mediana Edad , Pruebas Neuropsicológicas , Estudios Retrospectivos , Índice de Severidad de la EnfermedadRESUMEN
OBJECTIVES: Studies documenting the increased incidence of exercise-induced bronchospasm (EIB) in figure skaters have employed a method that incorporates on-ice exercise with rink-side spirometry. The literature suggests that bronchial provocation challenge testing is better than exercise testing for identifying EIB. To test this hypothesis in figure skaters, a unique athletic population that trains and competes in cold air, we compared these two methods in the same individuals. PATIENTS/METHODS: Two challenge tests were performed on a group of competitive figure skaters (n = 29, 26 female subjects; mean+/-SD age = 12.3+/-3.5 years): (1) rink-side (temperature = 14 degrees C, humidity = 60%) spirometry before and 1, 5, 10, and 15 min after 5 min of intense skating; and (2) eucapnic voluntary hyperventilation (EVH), breathing 5% CO2, 21% O2, balance N2 at a rate of 60% of maximum voluntary ventilation (not to exceed 70 L/min) for 5 min (temperature = 18 degrees C, humidity = 50%), with an identical pretest and posttest spirometry schedule. EIB was defined as at least one of the following: a > or =10% decline in Fev1; a > or = 20% decline in maximum midexpiratory flow rate; or a > or = 25% decline in peak expiratory flow rate. RESULTS: Sixteen of 29 skaters (55%) developed EIB: 9 were positive by on-ice testing; 12 were positive by EVH testing; 5 were positive on both tests; on-ice testing missed 7 skaters with EIB; EVH testing missed 4 with EIB. CONCLUSION: In the group of figure skaters studied, EVH challenge testing was better at identifying EIB than on-ice exercise testing. However, these data suggest that evaluation for EIB in athletes who train and compete in the cold should include exercise testing in cold air along with a challenge test such as EVH to increase the yield of positive responders.
Asunto(s)
Asma Inducida por Ejercicio/diagnóstico , Pruebas de Provocación Bronquial , Patinación/fisiología , Adolescente , Adulto , Niño , Prueba de Esfuerzo , Femenino , Humanos , Masculino , EspirometríaRESUMEN
BACKGROUND AND OBJECTIVES: Thirty to 50% of all COPD patients experience tissue wasting that may be caused by hypermetabolism, but the cause of the perturbed metabolic state is unclear. We hypothesized that the elevated O2 cost of ventilation (O2 COV) may be a contributing factor. All of the data are presented as means (+/-SEM). Ten hypoxemic (a PaO2 of 54+/-3 mm Hg) stable COPD patients (an FEV1/FVC ratio of 42+/-4%) and five healthy control subjects were studied. The patients were divided into two groups based on nutritional status. Group 1 (n = 6) was malnourished (a body mass index [BMI] of 17.6+/-0.7 kg/m2), and group 2 (n = 4) was normally nourished (a BMI of 26.0+/-3 kg/m2). The O2 COV was determined by measuring the change in the oxygen consumption (VO2) and the minute ventilation (VE) caused by CO2-induced hyperventilation. RESULTS AND CONCLUSIONS: Group 1 had an elevated O2 COV when compared to group 2 and the control group, respectively: 16.4+/-1.0 vs 9.7+/-1.0 and 2.4+/-0.2 mL O2/L of VE (p < 0.05). The VO2 at rest was higher for group 1 than for group 2 and the control group, respectively: 4.5+/-0.3 vs 3.1+/-0.5 and 3.4+/-0.2 mL/kg/min (p < 0.05). The resting energy expenditure (REE) % predicted for group 1 was also higher than group 2 and the control group, respectively: 125+/-3% vs 87+/-7% and 97+/-2% (p < 0.05). Significant correlations were observed that implicate the increased O2 COV as a cause of tissue wasting: O2 COV vs BMI (r = -0.79; p = 0.007), O2 COV vs REE % predicted (r = 0.66; p = 0.039), and REE % predicted vs BMI (r = -0.83; p = 0.003). The O2 COV was also correlated with lung function: FEV1/FVC vs O2 COV (r = -0.84; p = 0.002). We conclude that in these COPD patients the O2 COV is associated with an increased metabolic rate which, in turn adversely affects the nutritional status.
Asunto(s)
Enfermedades Pulmonares Obstructivas/metabolismo , Oxígeno/metabolismo , Ventilación Pulmonar , Humanos , Masculino , Persona de Mediana Edad , Trastornos Nutricionales/metabolismo , Estado Nutricional , Consumo de Oxígeno , Pérdida de PesoRESUMEN
BACKGROUND: Reduced muscle aerobic capacity in COPD patients has been demonstrated in several laboratories by phosphorus magnetic resonance spectroscopy and by analysis of oxygen uptake (VO2) kinetics. COPD patients are usually elderly, hypoxemic, poorly active with muscle atrophy, and often malnourished. Under these conditions there is usually reduction of O2 delivery to the tissues (bulk O2 flow), redistribution of fiber type within the muscle, capillary rarefaction, and decreased mitochondrial function, alterations all capable of reducing muscle aerobic capacity. In COPD, the effect of reduced body mass on muscle aerobic capacity has not been investigated (to our knowledge). METHODS: We studied 24 patients with stable COPD with moderate-to-severe airway obstruction (68+/-5 [SD] years; FEV1, 39+/-12% predicted; PaO2, 66+/-8 mm Hg; PaCO2, 41+/-3 mm Hg) with poor to normal nutritional status, as indicated by a low-normal percent of ideal body weight (IBW). Each subject first underwent 1-min maximal incremental cycle ergometer exercise for determination of VO2 peak and lactate threshold (LT). Subsequently, they performed a 10-min moderate (80% of LT-VO2) constant load exercise for determination of oxygen deficit (O2DEF) and mean response time VO2 (MRT). VO2, CO2 output (VCO2), and minute ventilation were measured breath by breath. RESULTS: Patients displayed low VO2 peak (1,094+/-47 [SE] mL/min), LT-VO2 (35+/-3% predicted O2 max), and higher MRT-VO2 (67+/-4 s). Univariate regression analysis showed that percent of IBW correlated with indexes of maximal and submaximal aerobic capacity: vs VO2 peak, R=0.53 (p<0.01); vs MRT R=-0.77 (p<0.001). Using stepwise regression analysis, MRT correlated (R2=-0.70) with percent of IBW (p<0.01) and with PaO2 (p<0.05). CONCLUSIONS: Reduced body mass has an independent negative effect on muscle aerobic capacity in COPD patients: this effect may explain the variability in exercise tolerance among patients with comparable ventilatory limitation.
Asunto(s)
Enfermedades Pulmonares Obstructivas/metabolismo , Músculo Esquelético/metabolismo , Consumo de Oxígeno/fisiología , Pérdida de Peso/fisiología , Anciano , Obstrucción de las Vías Aéreas/fisiopatología , Umbral Anaerobio/fisiología , Análisis de Varianza , Índice de Masa Corporal , Capilares/patología , Dióxido de Carbono/sangre , Dióxido de Carbono/metabolismo , Prueba de Esfuerzo , Tolerancia al Ejercicio , Volumen Espiratorio Forzado/fisiología , Humanos , Hipoxia/metabolismo , Lactatos/metabolismo , Enfermedades Pulmonares Obstructivas/patología , Enfermedades Pulmonares Obstructivas/fisiopatología , Espectroscopía de Resonancia Magnética , Masculino , Persona de Mediana Edad , Mitocondrias Musculares/fisiología , Fibras Musculares Esqueléticas/patología , Músculo Esquelético/irrigación sanguínea , Músculo Esquelético/patología , Atrofia Muscular/metabolismo , Atrofia Muscular/patología , Atrofia Muscular/fisiopatología , Trastornos Nutricionales/metabolismo , Trastornos Nutricionales/fisiopatología , Oxígeno/sangre , Fósforo , Análisis de Regresión , Respiración/fisiologíaRESUMEN
Dehydroepiandrosterone (DHEA) and its sulfate, DHEA-S, are plentiful adrenal steroid hormones that decrease with aging and may have significant neuropsychiatric effects. In this study, six middle-aged and elderly patients with major depression and low basal plasma DHEA f1p4or DHEA-S levels were openly administered DHEA (30-90 mg/d x 4 weeks) in doses sufficient to achieve circulating plasma levels observed in younger healthy individuals. Depression ratings, as well as aspects of memory performance significantly improved. One treatment-resistant patient received extended treatment with DHEA for 6 months: her depression ratings improved 48-72% and her semantic memory performance improved 63%. These measures returned to baseline after treatment ended. In both studies, improvements in depression ratings and memory performance were directly related to increases in plasma levels of DHEA and DHEA-S and to increases in their ratios with plasma cortisol levels. These preliminary data suggest DHEA may have antidepressant and promemory effects and should encourage double-blind trials in depressed patients.
Asunto(s)
Antidepresivos/uso terapéutico , Deshidroepiandrosterona/uso terapéutico , Trastorno Depresivo/tratamiento farmacológico , Anciano , Trastorno Depresivo/psicología , Femenino , Humanos , Hidrocortisona/sangre , Masculino , Memoria/efectos de los fármacos , Persona de Mediana Edad , Escalas de Valoración PsiquiátricaRESUMEN
Studies in healthy human subjects subjected to lower body positive pressure (LBPP) have failed to elucidate many of the physiologic effects of this maneuver. In 7 healthy, well-hydrated men we studied the following responses to LBPP (35 mm Hg, 1 hour, supine position): systemic and renal hemodynamics; urine volume (UV), urine osmolality (Uosm), and urine sodium level (UNaV); free water (CH20) and osmolar (Cosm) clearances; plasma renin activity (PRA); levels of aldosterone (PA), cortisol (CORT), norepinephrine (NE), atrial natriuretic peptide (ANP), and vasopressin (AVP); osmolality (Posm); and serum sodium level. Subjects were restudied on a control day with zero trouser pressure. The recorded changes (p < 0.05) when comparing the LBPP day with the control day were as follows: fractional Na+ reabsorption increased (98.7% +/- 0.2% to 99.3% +/- 0.1%) and UNaV decreased (0.19 +/- 0.03 mEq/min to 0.10 +/- 0.01 mEq/min), with concomitant increases in PRA (1.7 +/- 0.2 ng/ml/90 min to 4.5 +/- 1.8 ng/ml/90 min), PA (7.7 +/- 0.7 ng/dl to 9.3 +/- 1.5 ng/dl), and CORT (13.0 +/- 2.6 mg/dl to 19.2 +/- 3 mg/dl); the increase in blood pressure with LBPP (96 +/- 3 mm Hg to 112 +/- 4 mm Hg) was greater than that during control conditions. Renal plasma flow tended to display an interactive pattern across days, with a slight decline during LBPP (5%) and a slight elevation under control conditions (9%). On the LBPP day only, filtered Na+ declined (15 +/- I mEq/min to 12 +/- 1 mEq/min) as a function of reduced glomerular filtration rate (112 +/- 5 ml/min to 91 +/- 7 ml/min), blood volume decreased (by 2.7% +/- 0.7%), CO decreased (5.5 +/- 0.3 L/min to 4.7 +/- 0.3 L/min), and stroke volume declined (101 +/- 6 ml to 84 +/- 3 ml). On both days, NE increased (control, 221 +/- 23 pg/ml to 340 +/- 33 pg/ml; LBPP, 236 +/- 17 pg/ml to 369 +/- 31 pg/ml) and ANP increased (control, 47 +/- 7 pg/ml to 97 +/- 21 pg/ml; LBPP, 49 +/- 10 pg/ml to 104 +/- 30 pg/ml). We concluded that LBPP reduces renal sodium excretion. The mechanism for this reduction is not known, although it did occur in association with an increase in plasma renin activity, which in turn results from mechanical reduction of renal perfusion, stress-related CORT stimulation, a reflex-based elevation in peripheral vascular resistance leading to a reflex increase in plasma renin activity, or a combination of these.
Asunto(s)
Aldosterona/sangre , Hemodinámica/fisiología , Hidrocortisona/sangre , Riñón/fisiología , Presión , Renina/sangre , Adulto , Factor Natriurético Atrial/sangre , Ingestión de Líquidos/fisiología , Humanos , Masculino , Norepinefrina/sangre , Flujo Sanguíneo Regional/fisiología , Sodio/orina , UrinálisisAsunto(s)
Trastorno Depresivo/tratamiento farmacológico , Dexametasona/uso terapéutico , Ensayos Clínicos como Asunto , Trastorno Depresivo/sangre , Trastorno Depresivo/psicología , Dexametasona/administración & dosificación , Dexametasona/efectos adversos , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Humanos , Hidrocortisona/sangre , Infusiones Intravenosas , Resultado del TratamientoRESUMEN
Many highly trained athletes experience exercise-induced bronchospasm (EIB): studies describing EIB in figure skaters, who may be at increased risk of EIB due to rink temperatures (7 to 10 degrees C), have not been published. We studied professionally coached figure skaters (n = 124) for EIB by spirometry at rinkside immediately before a simulated long program and at 0 to 1, 5, 10, and 15 min postexercise. Postexercise spirometry revealed the presence of EIB (a decrease from baseline in FEV1 of at least 10%) in 43 skaters, while the remainder (n = 81, control group) remained relatively stable. Pre-exercise FEV1, FVC, and FEV1/FVC ratio were not different between groups. The EIB group had significantly lower FEV1 vs baseline at each measurement following exercise: baseline, 3.08 +/- 0.13; 0 to 1 min postexercise, 2.81 +/- 0.13 (p < 0.05); 5 min postexercise, 2.77 +/- 0.14 (p < 0.05); 10 min postexercise, 2.78 +/- 0.13 (p < 0.05); 15 min postexercise, 2.78 +/- 0.13 (p < 0.05). The EIB group also had lower FVC: baseline, 3.48 +/- 0.16; 0 to 1 min postexercise, 3.16 +/- 0.15 (p < 0.05); 5 min postexercise, 3.19 +/- 0.15 (p < 0.05); 10 min postexercise, 3.27 +/- 0.16 (p < 0.05); 15 min postexercise, 3.26 +/- 0.16 (p < 0.05). Control subjects, however, experienced no decline in these variables. In conclusion, the incidence of EIB in the figure skaters measured during this investigation (43 of 124 = 35%) is greater than that of the population at large and other highly trained athletes, signifying that screening for EIB and therapeutic follow-up are reasonable considerations for participants in this sport.
Asunto(s)
Asma Inducida por Ejercicio/fisiopatología , Broncoconstricción , Patinación , Adolescente , Adulto , Niño , Volumen Espiratorio Forzado , Humanos , EspirometríaRESUMEN
Inadequate O2 supply may impair intramuscular oxidative metabolism and O2 availability may modulate ATP production within exercising muscle. Therefore, we studied ATP flux from anaerobic glycolysis, the creatine kinase reaction, and oxidative phosphorylation using 31P-magnetic resonance spectroscopy kinetic data collected during exercise. We examined six chronic obstructive pulmonary disease (COPD) patients with severe hypoxemia (group 1), seven COPD patients with mild hypoxemia (group 2), and seven healthy control subjects. Exercise (90-s isometric contraction of the gastrocnemius-soleus muscle group, 40% of max) was performed on room air for all subjects; for COPD patients, it was repeated during supplemental O2 at identical power outputs, with 60-min rest between the two sets. In group 1 (air vs. O2), oxidative phosphorylation ATP production was lower (P < 0.05), anaerobic glycolysis ATP production was higher (P < 0.05), and anaerobic glycolysis plus creatine kinase ATP production tended to be higher (P = 0.06). In group 2, no differences were observed across conditions. Assuming that mitochondrial size, density, function, and redox state were not affected by acute changes in the inspired O2 fraction, reduced O2 availability is the remaining factor that could have limited oxidative ATP production during hypoxemia. In conclusion, in severely hypoxemic COPD patients, O2 availability apparently limits intramuscular oxidative metabolism because acute hypoxemia increases anaerobic and decreases aerobic ATP production.
Asunto(s)
Adenosina Trifosfato/metabolismo , Enfermedades Pulmonares Obstructivas/metabolismo , Oxígeno/metabolismo , Adenosina Difosfato/metabolismo , Anciano , Metabolismo Energético , Ejercicio Físico , Humanos , Imagen por Resonancia Magnética , Persona de Mediana EdadRESUMEN
We evaluated the effect of supplemental O2 on energy metabolism of hypoxemic humans by measuring O2 uptake (VO2) kinetics and other cardiorespiratory parameters in nine male chronic obstructive pulmonary disease (COPD) patients and seven age-matched control subjects (on air and on 30% O2) at rest and during moderate cycle ergometer exercise. Heart rate, ventilation, VO2, CO2 output, respiratory exchange ratio, O2 cost of work, and work efficiency were measured with a computerized metabolic cart; O2 deficit and VO2 time courses were calculated. In COPD patients, 30% O2 breathing resulted in 1) reduction of O2 deficit (from 488 +/- 34 ml in air to 398 +/- 27 ml in O2; P < 0.05) and phase 2 VO2 time constant (from 116 +/- 13 s in air to 74 +/- 12 s in O2; P < 0.05); 2) a smaller steady-state increment in CO2 output than in room air (315 +/- 17 ml/min in O2 vs. 358 +/- 27 ml/min in air; P < 0.02), which resulted in a lower exercise respiratory exchange ratio (0.75 +/- 0.02 in O2 vs. 0.80 +/- 0.02 in air; P < 0.02); and 3) reduced steady-state ventilation (22.6 +/- 1.0 l/min in O2 vs. 25.4 +/- 1.1 l/min in air; P < 0.05). In conclusion, 30% O2 breathing accelerated exercise VO2 kinetics in mildly hypoxemic COPD patients. The observed VO2 kinetics improvement with O2 supplementation is consistent with an enhancement of aerobic metabolism in skeletal muscles during moderate exercise.
Asunto(s)
Ejercicio Físico , Enfermedades Pulmonares Obstructivas/metabolismo , Oxígeno/metabolismo , Anciano , Dióxido de Carbono/metabolismo , Humanos , Cinética , Masculino , Persona de Mediana Edad , Ventilación Pulmonar , Factores de TiempoRESUMEN
Inspiratory muscle fatigue, a common event in patients in the intensive care unit, is under multifactorial control. To test the hypothesis that systemic oxygenation is a factor in this event, we subjected five healthy males (age 42 +/- 3 yr) to continuous inspiratory pressure (75% of maximal inspiratory pressure, -95 +/- 5 cmH2O) with the use of a controlled breathing pattern while they breathed normoxic (21% O2), hyperoxic (30% O2), and hypoxic (13% O2) mixtures. Inspiratory muscle endurance (IME; time that pressure could be maintained) and other cardiorespiratory parameters were monitored. Room air IME (3.3 +/- 0.4 min) was shortened (P < 0.05) during 13% O2 breathing (1.6 +/- 0.4 min) but was unaffected during 30% O2 breathing (4.0 +/- 0.6 min). Inspiratory loading lowered the respiratory exchange ratio (RER) during the 21 and 30% O2 trials (1.02 +/- 0.01 to 0.80 +/- 0.03% and 1.05 +/- 0.05 to 0.69 +/- 0.01%, respectively) but not during the 13% O2 trials (1.03 +/- 0.03 to 1.06 +/- 0.07%). At the point of fatigue during the 13% O2 trials, RER was lower compared with the same time point during the 21 and 30% O2 trials. A significant relationship was observed between IME and RER (r = -0.73, P = 0.002) but not between IME and any of the other measured variables. We conclude that 1) hypoxemia impairs the ability of the inspiratory muscles to sustain a mechanical challenge and 2) substrate utilization of the respiratory muscles shifts toward a greater reliance on lipid metabolism when O2 is readily available; this shift was not observed when the O2 supply was reduced.
Asunto(s)
Fatiga/metabolismo , Músculos Respiratorios/metabolismo , Adulto , Humanos , Hipoxia/metabolismo , Metabolismo de los Lípidos , Masculino , Consumo de Oxígeno/fisiología , Resistencia Física/fisiología , Pruebas de Función Respiratoria , Relación Ventilacion-PerfusiónRESUMEN
Ketoconazole, an antiglucocorticoid drug, was administered to 10 hypercortisolemic depressed patients for up to 6 weeks. Three patients dropped out because of side effects or intercurrent illness. The remaining seven had significant ketoconazole-associated decreases in serum cortisol levels and in depression ratings. Antiglucocorticoid agents may be useful probes for investigating the sequelae of hypercortisolemia in patients with major depression.
Asunto(s)
Trastorno Depresivo/sangre , Hidrocortisona/sangre , Cetoconazol/farmacología , Adulto , Anciano , Depresión Química , Trastorno Depresivo/fisiopatología , Trastorno Depresivo/psicología , Femenino , Humanos , Hidrocortisona/fisiología , Masculino , Persona de Mediana Edad , Escalas de Valoración Psiquiátrica , Índice de Severidad de la EnfermedadRESUMEN
It is known that the O2 COV in COLD is high; O2 administration to these patients lowers airway resistance, a major determinant of the COV. Thus, O2 should lower the COV. We measured the COV in ten stable COLD patients and five normal control subjects breathing room air and 30 percent O2. Results indicate that the COV of our patients was elevated above that of control subjects, was related to disease severity, and was decreased with 30 percent O2. The COV of control subjects also was lowered by O2. At rest, O2 lowered VE, VEQ O2 and HR. During submaximal exercise O2 lowered VE, reduced VEQ O2 and extended total exercise time. An inverse correlation was noted between COV and maximal O2 uptake. Thus, in stable COLD, the COV is elevated in proportion to the degree of airway obstruction, inversely related to exercise capacity and lowered by O2 administration.