RESUMO
Spirometry has been used as the main strategy for assessing ventilatory changes related to occupational exposure to particulate matter (OEPM). However, in some cases, as one of its limitations, it may not be sensitive enough to show abnormalities before extensive damage, as seen in restrictive lung diseases. Therefore, we hypothesized that cardiopulmonary exercise testing (CPET) may be better than spirometry to detect early ventilatory impairment caused by OEPM. We selected 135 male workers with at least one year of exposure. After collection of self-reported socioeconomic status, educational level, and cardiovascular risk data, participants underwent spirometry, CPET, body composition assessment (bioelectrical impedance), and triaxial accelerometry (for level of physical activity in daily life). CPET was performed using a ramp protocol on a treadmill. Metabolic, cardiovascular, ventilatory, and submaximal relationships were measured. We compared 52 exposed to 83 non-exposed workers. Multiple linear regressions were developed using spirometry and CPET variables as outcomes and OEPM as the main predictor, and adjusted by the main covariates. Our results showed that OEPM was associated with significant reductions in peak minute ventilation, peak tidal volume, and breathing reserve index. Exposed participants presented shallower slope of ΔVT/ΔlnVÌE (breathing pattern), i.e., increased tachypneic breathing pattern. The OEPM explained 7.4% of the ΔVT/ΔlnVÌE variability. We found no significant influence of spirometric indices after multiple linear regressions. We conclude that CPET might be a more sensitive feature of assessing early pulmonary impairment related to OEPM. Our cross-sectional results suggested that CPET is a promising tool for the screening of asymptomatic male workers.
Assuntos
Aptidão Cardiorrespiratória/fisiologia , Exposição Ambiental/efeitos adversos , Pneumopatias/etiologia , Exposição Ocupacional/efeitos adversos , Material Particulado/efeitos adversos , Adulto , Estudos Transversais , Teste de Esforço/métodos , Humanos , Pneumopatias/diagnóstico , Pneumopatias/fisiopatologia , Troca Gasosa Pulmonar , Fatores de Risco , EspirometriaRESUMO
The autonomic nervous system maintains homeostasis, which is the state of balance in the body. That balance can be determined simply and noninvasively by evaluating heart rate variability (HRV). However, independently of autonomic control of the heart, HRV can be influenced by other factors, such as respiratory parameters. Little is known about the relationship between HRV and spirometric indices. In this study, our objective was to determine whether HRV correlates with spirometric indices in adults without cardiopulmonary disease, considering the main confounders (e.g., smoking and physical inactivity). In a sample of 119 asymptomatic adults (age 20-80 years), we evaluated forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). We evaluated resting HRV indices within a 5-min window in the middle of a 10-min recording period, thereafter analyzing time and frequency domains. To evaluate daily physical activity, we instructed participants to use a triaxial accelerometer for 7 days. Physical inactivity was defined as <150 min/week of moderate to intense physical activity. We found that FVC and FEV1, respectively, correlated significantly with the following aspects of the RR interval: standard deviation of the RR intervals (r =0.31 and 0.35), low-frequency component (r =0.38 and 0.40), and Poincaré plot SD2 (r =0.34 and 0.36). Multivariate regression analysis, adjusted for age, sex, smoking, physical inactivity, and cardiovascular risk, identified the SD2 and dyslipidemia as independent predictors of FVC and FEV1 (R2=0.125 and 0.180, respectively, for both). We conclude that pulmonary function is influenced by autonomic control of cardiovascular function, independently of the main confounders.
Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Frequência Cardíaca/fisiologia , Pulmão/fisiologia , Fumar/fisiopatologia , Sistema Nervoso Autônomo/fisiologia , Estudos Transversais , Dislipidemias/fisiopatologia , Volume Expiratório Forçado/fisiologia , Comportamento Sedentário , Espirometria , Capacidade Vital/fisiologiaRESUMO
The autonomic nervous system maintains homeostasis, which is the state of balance in the body. That balance can be determined simply and noninvasively by evaluating heart rate variability (HRV). However, independently of autonomic control of the heart, HRV can be influenced by other factors, such as respiratory parameters. Little is known about the relationship between HRV and spirometric indices. In this study, our objective was to determine whether HRV correlates with spirometric indices in adults without cardiopulmonary disease, considering the main confounders (e.g., smoking and physical inactivity). In a sample of 119 asymptomatic adults (age 20-80 years), we evaluated forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). We evaluated resting HRV indices within a 5-min window in the middle of a 10-min recording period, thereafter analyzing time and frequency domains. To evaluate daily physical activity, we instructed participants to use a triaxial accelerometer for 7 days. Physical inactivity was defined as <150 min/week of moderate to intense physical activity. We found that FVC and FEV1, respectively, correlated significantly with the following aspects of the RR interval: standard deviation of the RR intervals (r =0.31 and 0.35), low-frequency component (r =0.38 and 0.40), and Poincaré plot SD2 (r =0.34 and 0.36). Multivariate regression analysis, adjusted for age, sex, smoking, physical inactivity, and cardiovascular risk, identified the SD2 and dyslipidemia as independent predictors of FVC and FEV1 (R2=0.125 and 0.180, respectively, for both). We conclude that pulmonary function is influenced by autonomic control of cardiovascular function, independently of the main confounders.
Assuntos
Frequência Cardíaca/fisiologia , Pulmão/fisiologia , Comportamento Sedentário , Fumar/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Sistema Nervoso Autônomo/fisiologia , Fatores de Confusão Epidemiológicos , Estudos Transversais , Dislipidemias/fisiopatologia , Feminino , Volume Expiratório Forçado/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Espirometria , Capacidade Vital/fisiologiaRESUMO
The 6-minute walk test (6MWT) is a simple field test that is widely used in clinical settings to assess functional exercise capacity. However, studies with healthy subjects are scarce. We hypothesized that the 6MWT might be useful to assess exercise capacity in healthy subjects. The purpose of this study was to evaluate 6MWT intensity in middle-aged and older adults, as well as to develop a simple equation to predict oxygen uptake ( V ˙ O 2 ) from the 6-min walk distance (6MWD). Eighty-six participants, 40 men and 46 women, 40-74 years of age and with a mean body mass index of 28±6 kg/m2, performed the 6MWT according to American Thoracic Society guidelines. Physiological responses were evaluated during the 6MWT using a K4b2 Cosmed telemetry gas analyzer. On a different occasion, the subjects performed ramp protocol cardiopulmonary exercise testing (CPET) on a treadmill. Peak V ˙ O 2 in the 6MWT corresponded to 78±13% of the peak V ˙ O 2 during CPET, and the maximum heart rate corresponded to 80±23% of that obtained in CPET. Peak V ˙ O 2 in CPET was adequately predicted by the 6MWD by a linear regression equation: V ˙ O 2 mL·min-1·kg-1 = -2.863 + (0.0563×6MWDm) (R2=0.76). The 6MWT represents a moderate-to-high intensity activity in middle-aged and older adults and proved to be useful for predicting cardiorespiratory fitness in the present study. Our results suggest that the 6MWT may also be useful in asymptomatic individuals, and its use in walk-based conditioning programs should be encouraged.
Assuntos
Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Teste de Esforço , Voluntários Saudáveis , Caminhada/fisiologia , Estudos Transversais , Dióxido de Carbono/fisiologia , Consumo de Oxigênio/fisiologia , Espirometria , Telemetria , Fatores de TempoRESUMO
The 6-minute walk test (6MWT) is a simple field test that is widely used in clinical settings to assess functional exercise capacity. However, studies with healthy subjects are scarce. We hypothesized that the 6MWT might be useful to assess exercise capacity in healthy subjects. The purpose of this study was to evaluate 6MWT intensity in middle-aged and older adults, as well as to develop a simple equation to predict oxygen uptake ( V Ë O 2 ) from the 6-min walk distance (6MWD). Eighty-six participants, 40 men and 46 women, 40-74 years of age and with a mean body mass index of 28±6 kg/m2, performed the 6MWT according to American Thoracic Society guidelines. Physiological responses were evaluated during the 6MWT using a K4b2 Cosmed telemetry gas analyzer. On a different occasion, the subjects performed ramp protocol cardiopulmonary exercise testing (CPET) on a treadmill. Peak V Ë O 2 in the 6MWT corresponded to 78±13% of the peak V Ë O 2 during CPET, and the maximum heart rate corresponded to 80±23% of that obtained in CPET. Peak V Ë O 2 in CPET was adequately predicted by the 6MWD by a linear regression equation: V Ë O 2 mL·min-1·kg-1 = -2.863 + (0.0563×6MWDm) (R2=0.76). The 6MWT represents a moderate-to-high intensity activity in middle-aged and older adults and proved to be useful for predicting cardiorespiratory fitness in the present study. Our results suggest that the 6MWT may also be useful in asymptomatic individuals, and its use in walk-based conditioning programs should be encouraged.
Assuntos
Teste de Esforço , Voluntários Saudáveis , Caminhada/fisiologia , Adulto , Idoso , Dióxido de Carbono/fisiologia , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio/fisiologia , Espirometria , Telemetria , Fatores de TempoRESUMO
BACKGROUND: Oxidative stress plays an important role in the pathophysiology of diabetes mellitus. The aim of this study was to evaluate the formation of cholesterol oxides (ChOx) as biomarkers of oxidative stress in subjects with impaired glucose tolerance (IGT) and diabetes. METHODS: Blood plasma levels of cholesterol oxidation products were determined in the following groups: type 1 diabetes mellitus (DM1), type 2 diabetes (DM2), impaired glucose tolerance (IGT), children without diabetes (C1) and adults without diabetes (C2). The serum levels of cholest-5-ene-3alpha,7alpha-diol (7alpha-hydroxycholesterol, 7alpha-OH), cholest-5-ene-3beta,7beta-diol (7beta-hydroxycholesterol, 7beta-OH), 3beta-hydroxycholest-5-7-one (7-ketocholesterol, 7-K), 5alpha-cholestane-3beta,5,6beta-triol (cholestanetriol), 5,6alpha-epoxy-5alpha-cholestan-3alpha-ol (cholesterol-5alpha,6alpha-epoxide,), 5,6beta-epoxy-5beta-cholestan-3beta-ol (cholesterol-5beta,6beta-epoxide) and cholest-5-eno-3beta,25-diol (25-hydroxycholesterol, 25-OH) (trivial name and abbreviations indicated in parentheses) were quantified by gas chromatography using flame ionization detection. RESULTS: The levels of total ChOx were elevated in the DM1 and DM2 groups compared to age-matched subjects without diabetes (p < 0.05). The concentrations of 7beta-hydroxycholesterol, cholesterol-alpha-epoxide and cholesterol-beta-epoxide were higher in the blood plasma of subjects in the DM2 group than in the blood plasma of subjects in the C2 and IGT groups (p < 0.05). Treatment of type 2 diabetic patients with oral hypoglycemic drugs associated with insulin resulted in lower concentrations of nitrotyrosine in the blood plasma without significant changes in the concentrations of glucose and glycated hemoglobin. Moreover, combination with statins in both treatments decreased the concentrations of ChOx. CONCLUSIONS: ChOx are suitable biomarkers of oxidative stress and may be useful in clinical studies to follow drug effects on lipid oxidative modifications in diabetic patients.
Assuntos
Colesterol/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Estresse Oxidativo/fisiologia , Adolescente , Adulto , Idoso , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Biomarcadores , Criança , Colestanóis/sangue , Colesterol/análogos & derivados , Colesterol/sangue , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Feminino , Intolerância à Glucose/sangue , Humanos , Hidroxicolesteróis/sangue , Hipoglicemiantes/uso terapêutico , Insulina/uso terapêutico , Cetocolesteróis/sangue , Masculino , Pessoa de Meia-IdadeRESUMO
Background Oxidative stress plays an important role in the pathophysiology of diabetes mellitus. The aim of this study was to evaluate the formation of cholesterol oxides (ChOx) as biomarkers of oxidative stress in subjects with impaired glucose tolerance (IGT) and diabetes. Methods Blood plasma levels of cholesterol oxidation products were determined in the following groups: type 1 diabetes mellitus (DM1), type 2 diabetes (DM2), impaired glucose tolerance (IGT), children without diabetes (C1) and adults without diabetes (C2). The serum levels of cholest-5-ene-3£/,7£/-diol (7£/-hydroxycholesterol, 7£/-OH), cholest- 5-ene-3£],7£]-diol (7£]-hydroxycholesterol, 7£]-OH), 3£]-hydroxycholest-5-7- one (7-ketocholesterol, 7-K), 5£/-cholestane-3£],5,6£]-triol (cholestanetriol), 5,6£/-epoxy-5£/-cholestan-3£/-ol (cholesterol-5£/,6£/-epoxide,), 5,6£]-epoxy- 5£]-cholestan-3£]-ol (cholesterol-5£],6£]-epoxide) and cholest-5-eno-3£],25-diol (25-hydroxycholesterol, 25-OH) (trivial name and abbreviations indicated in parentheses) were quantified by gas chromatography using flame ionization detection. Results The levels of total ChOx were elevated in the DM1 and DM2 groups compared to age-matched subjects without diabetes (p < 0.05).The concentrations of 7£]-hydroxycholesterol, cholesterol-£/-epoxide and cholesterol-£]-epoxide were higher in the blood plasma of subjects in the DM2 group than in the blood plasma of subjects in the C2 and IGT groups (p < 0.05). Treatment of type 2 diabetic patients with oral hypoglycemic drugs associated with insulin resulted in lower concentrations of nitrotyrosine in the blood plasma without significant changes in the concentrations of glucose and glycated hemoglobin. Moreover, combination with statins in both treatments decreased the concentrations of ChOx.Conclusions ChOx are suitable biomarkers of oxidative stress and may be useful in clinical studies to follow drug effects on lipid oxidative modifications in diabetic patients. Copyright ÆÉ 2006 John Wiley & Sons, Ltd.
Assuntos
Colesterol , Hipoglicemia , Inibidores de Hidroximetilglutaril-CoA Redutases , Insulina , Lipídeos , ÓxidosRESUMO
Long term follow-up of patients submitted to treatment of parasellar tumours region is important for the detection of late therapeutic complications. In this study the authors conducted an evaluation of six patients with craniopharyngioma, one with germinoma, one with meningioma, and one epidermoid cyst. All above tumours were localized at parasellar region. Six out of nine patients had been treated both by surgery and by radiotherapy and the other three surgically only, on an average 3.8 +/- 3.2 years before this observation was carried out. Five patients were female with their ages average 24.3 +/- 18.8 years old. Evaluation consisted: in the first place, an intravenous infusion of thyrotropin-releasing hormone (TRH, 200 micrograms), gonadotropin-releasing hormone (GnRH, 100 micrograms), and insulin tolerance test (0.1 IU/Kg, regular insulin); and secondly, in measurements of pituitary hormones secretion at different time points--0, 20, 40, 60 and 80 minutes. We found both diminished response of growth hormone and cortisol in all the patients. Seven out of nine patients did not have adequate response to follicle-stimulating hormone. Three out of nine responded unsatisfactory to luteinizing hormone. Four out of nine showed inadequate responses to prolactin as well as, two out of eight to thyrotropin. We concluded that: (a) growth hormone and cortisol deficiency are the most frequent finding in these patients; (b) post-radiotherapy lesions can be located in the hypothalamus or pituitary, or even in both; (c) hypophysial and hypothalamic cells sensitivity to irradiation is different, according to their respective hormones; and (d) it is necessary a frequent endocrinologic follow-up of patients to detect late hormonal deficiencies.
Assuntos
Neoplasias Encefálicas/radioterapia , Hipotálamo/efeitos da radiação , Hipófise/efeitos da radiação , Hormônios Adeno-Hipofisários/sangue , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Hormônio Liberador de Gonadotropina , Hormônio do Crescimento/metabolismo , Humanos , Insulina , Masculino , Pessoa de Meia-Idade , Prolactina/metabolismo , Hormônio Liberador de TireotropinaRESUMO
A case of patient with Cushing's syndrome due to an adrenal adenoma who conceived twice in the course of the disease is described. Pregnancy is known to be rare in these patients. When first seen she had some manifestations of Cushing's syndrome, but follow-up was lost prior to complete investigation. She conceived a few months later and gave birth to a 900 g premature liveborn infant. At the beginning of a second pregnancy, an adrenal adenoma was resected. The remainder of her pregnancy was uneventful and she delivered a normal fullterm 4 kg infant. Both children show normal physical and neurological development up to date. The patient presented herein illustrates the early diagnosis of Cushing's syndrome during pregnancy is extremely important, and early surgical treatment is indicated in order to avoid maternal and fetal complications.
Assuntos
Adenoma/fisiopatologia , Neoplasias do Córtex Suprarrenal/fisiopatologia , Síndrome de Cushing/fisiopatologia , Complicações Neoplásicas na Gravidez/fisiopatologia , Adenoma/cirurgia , Neoplasias do Córtex Suprarrenal/cirurgia , Adulto , Feminino , Humanos , Gravidez , Complicações Neoplásicas na Gravidez/cirurgiaRESUMO
To study the effects of clonidine on growth and plasma somatomedin C (SmC) levels, 42 male Wistar rats aged 28 days and weighing 75 to 105 g were given clonidine (1.5 micrograms/ml in drinking water), or filtered water alone and were weighed weekly. After 0, 4 and 8 weeks, the animals were sacrificed under ether anesthesia, their length was measured and blood was collected by cardiac puncture for measurement of SmC concentration. Growth and the weight/length ratio were lower, and plasma SmC levels (mean +/- SEM) were greater in the treated groups after 4 (616 +/- 44.7 vs 433.2 +/- 39.38 ng/ml, P less than 0.01) and 8 (595.2 +/- 28.3 vs 412.66 +/- 39.01 ng/ml, P less than 0.01) weeks of treatment, suggesting that clonidine treatment increased growth hormone secretion. In other experiments, treated animals showed increased food intake only during the first week of treatment and decreased epididymal fat weight after 3 weeks (1.412 +/- 0.0536 vs 1.6 +/- 0.1336 mg/100 g body weight, P less than 0.01). The results suggest that clonidine acts at the level of the central nervous system involving transitory modulation of food intake, as well as on the regulation of energy metabolism.