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1.
Int J Sports Med ; 36(9): 769-75, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25901949

RESUMO

Physical fitness has been reported to decrease the risk of lifestyle-related diseases. The present study evaluated genome-wide methylation under the hypothesis that interval walking training (IWT) imparted beneficial effects on health, particularly by epigenetically ameliorating susceptibility to inflammation. We screened DNA from peripheral blood samples via genome-wide microarray for genes whose methylation was affected by IWT, paying special attention to promoter regions, and identified over 40 hyper- or hypo-methylated genes following IWT that were not witnessed in controls. We next selected genes in which the degree of methylation change in the promoter region was correlated with energy consumption following IWT. In this way, we found the NFκB2 gene to have increased methylation in multiple regions of its promoter sequence following participation in an exercise regimen. Next, IWT-induced NFκB2 hyper-methylation was confirmed by a quantitative PyroSequencing assessment of methylation in samples obtained from independent subjects who also underwent IWT. The increase in NFκB2 gene promoter methylation by IWT indicates that this regimen may suppress pro-inflammatory cytokines. Thus, these results provide an additional line of evidence that IWT is advantageous in promoting health from an epigenetic perspective by ameliorating susceptibility to inflammation.


Assuntos
Envelhecimento/genética , Metabolismo Energético/genética , Subunidade p52 de NF-kappa B/genética , Educação Física e Treinamento/métodos , Caminhada/fisiologia , Idoso , Metilação de DNA , Estudo de Associação Genômica Ampla , Humanos , Inflamação/genética , Inflamação/prevenção & controle , Pessoa de Meia-Idade , Regiões Promotoras Genéticas , Análise de Sequência de DNA
2.
Scand J Med Sci Sports ; 23(5): e286-92, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23647307

RESUMO

We examined whether post-exercise macronutrient supplementation during a 5-month home-based interval walking training (IWT) accelerated exercise-induced increases in skeletal muscle mass and strength in healthy middle-aged and older women. Thirty-five women (41-78 years) were randomly divided into two groups: IWT alone (CNT, n = 18) or IWT plus post-exercise macronutrient (7.6 g protein, 32.5 g carbohydrate, and 4.4 g fat) supplementation (NUT, n = 17). For IWT, all subjects were instructed to repeat five or more sets of 3-min low-intensity walking at 40% peak aerobic capacity (Vo2 peak ), followed by a 3-min high-intensity walking above 70% Vo2 peak per day for 4 or more days per week. We determined Vo2 peak , thigh muscle tissue area by computer tomography, and thigh muscle strength in all subjects before and after IWT. We found that an increase in hamstring muscle tissue area was 2.8 ± 1.2% in NUT vs -1.0 ± 0.7% in CNT and that in isometric knee flexion force was 16.3 ± 3.7% in NUT vs 6.5 ± 3.0% in CNT; both were significantly higher in NUT than in CNT (both, P < 0.001). Thus, post-exercise macronutrient supplementation enhanced the increases in thigh muscle mass and strength, although partially, in home-based IWT in middle-aged and older women.


Assuntos
Articulação do Joelho/fisiologia , Força Muscular/fisiologia , Músculo Esquelético/crescimento & desenvolvimento , Caminhada/fisiologia , Adulto , Idoso , Carboidratos da Dieta/administração & dosagem , Gorduras na Dieta/administração & dosagem , Proteínas Alimentares/administração & dosagem , Suplementos Nutricionais , Feminino , Humanos , Japão , Pessoa de Meia-Idade , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/fisiologia , Consumo de Oxigênio , Coxa da Perna/fisiologia
3.
Br J Sports Med ; 45(3): 216-24, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19846423

RESUMO

HYPOTHESIS: Whether increasing peak aerobic capacity for walking (VO(2peak)) by interval walking training (IWT) is closely linked with decreasing the indices of lifestyle-related diseases (LSDs) in middle-aged and older people were examined. METHODS: For 4 months from April to September 2005 or 2006, 246 males and 580 females (∼65 years) performed IWT consisting of ≥5 sets of fast walking at ≥70% VO(2peak) for 3 min followed by slow walking at ≤40% VO(2peak) for 3 min ≥4 days/week. Before and after IWT, we measured VO(2peak), body mass index (BMI), %body fat, arterial blood pressure, thigh muscle strength and blood parameters. We analysed 198 males and 468 females who had undergone all the measurements both before and after IWT. To examine the hypothesis, we divided the subjects equally into three groups according to their pretraining VO(2peak): low, middle and high groups for each sex. RESULTS: Before training, it was found that thigh muscle strength and blood high-density lipoprotein cholesterol concentration were lower, whereas body weight, BMI, %body fat, arterial blood pressure and blood glucose were higher in the low group than the high group (all, p<0.05). After training, although VO(2peak) and thigh muscle strength increased and body weight, BMI, %body fat, blood pressure and blood glucose concentration decreased in all groups (all, p<0.05), the changes were greatest in the low group for both sexes. CONCLUSION: VO(2peak) at baseline and changes in response to training were closely linked with indices of LSDs.


Assuntos
Doença Crônica/prevenção & controle , Aptidão Física/fisiologia , Caminhada/fisiologia , Idoso , Glicemia/metabolismo , Pressão Sanguínea/fisiologia , Feminino , Humanos , Estilo de Vida , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Consumo de Oxigênio/fisiologia
4.
Int J Sports Med ; 31(9): 671-5, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20200803

RESUMO

Chronic moderate exercise has been reported to reduce pro-inflammatory cytokines. To analyze the molecular mechanisms by which training exerts these effects, the epigenetic influences of age and exercise on the ASC gene, which is responsible for IL-1beta and IL-18 secretion, were investigated by ASC gene methylation. Further, the relationship between carcinogenesis and exercise, and methylation of the P15 tumor suppressive gene was also analyzed. High-intensity interval walking exercise, consisting of 3 min low-intensity walking at 40% of peak aerobic capacity followed by a 3 min high-intensity walking period above 70% of peak aerobic capacity, was continued for 6 months. Peripheral blood DNA extracts from young control (n=34), older control (n=153), and older exercise (n=230) groups were then analyzed by pyrosequencing for DNA methylation. Methylation of ASC decreased significantly with age (young control vs. older control, p<0.01), which is indicative of an age-dependent increase in ASC expression. Compared to the older control group, the degree of ASC methylation was higher in the older exercise group (older control vs. older exercise: p<0.01), and presumably lower ASC expression. Neither exercise nor age affected the methylation of the P15. In summary, chronic moderate exercise appears to attenuate the age-dependent decrease in ASC methylation, implying suppression of excess pro-inflammatory cytokines through reduction of ASC expression.


Assuntos
Proteínas do Citoesqueleto/genética , Metilação de DNA/fisiologia , Exercício Físico/fisiologia , Regulação da Expressão Gênica/fisiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Proteínas Adaptadoras de Sinalização CARD , Inibidor de Quinase Dependente de Ciclina p15/genética , Epigênese Genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Sequência de DNA/métodos , Caminhada/fisiologia , Adulto Jovem
6.
Med Phys ; 36(3): 870-5, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19378747

RESUMO

The authors have investigated the dependency of radiation quality and absorbed dose on radiation field size in therapeutic carbon beams. The field size of the broad beam, formed using the passive technique, was controlled from 20 to 100 mm per side with a multileaf collimator. The absorbed dose and radiation quality on the beam center were evaluated at several depths in a water phantom using microdosimetric technique in experiments and Monte Carlo simulations. With an increase in the field size, the radiation quality was reduced, although the absorbed dose grew at the center of the field. This indicates that the dose and radiation quality at the center of the broad beam are influenced by particles from the off-center region via large-angle scattering and that such particles have relatively low radiation quality and mainly consist of fragment particles. Because such a tendency appeared to be more remarkable in the deeper region of the water phantom, it is likely that fragment particles that are born in a water phantom have a marked role in determining the field size effect.


Assuntos
Carbono/uso terapêutico , Radioterapia Conformacional/métodos , Radioterapia de Alta Energia/métodos , Fenômenos Biofísicos , Humanos , Método de Monte Carlo , Imagens de Fantasmas , Planejamento da Radioterapia Assistida por Computador/métodos , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos , Radioterapia Conformacional/instrumentação , Radioterapia Conformacional/estatística & dados numéricos , Radioterapia de Alta Energia/instrumentação , Radioterapia de Alta Energia/estatística & dados numéricos , Eficiência Biológica Relativa , Espalhamento de Radiação
7.
J Appl Physiol (1985) ; 91(4): 1520-8, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11568132

RESUMO

Plasma volume (PV) expansion by endurance training and/or heat acclimatization is known to increase aerobic and thermoregulatory capacities in humans. Also, higher erythrocyte volume (EV) fractions in blood are known to improve these capacities. We tested the hypothesis that training in a hypobaric hypoxic and warm environment would increase peak aerobic power (VO(2)(peak)) and forearm skin vascular conductance (FVC) response to increased esophageal temperature (T(es)) more than training in either environment alone, by increasing both PV and EV. Twenty men were divided into four training regimens (n = 5 each): low-altitude cool (610-m altitude, 20 degrees C ambient temperature, 50% relative humidity), high-altitude cool (2,000 m, 20 degrees C), low-altitude warm (610 m, 30 degrees C), and high-altitude warm (HW; 2,000 m, 30 degrees C). They exercised on a cycle ergometer at 60% VO(2)(peak) for 1 h/day for 10 days in a climate chamber. After training, PV increased in all trials, but EV increased in only high-altitude trials (both P < 0.05). VO(2)(peak) increased in all trials (P < 0.05) but without any significant differences among trials. FVC response to increased T(es) was measured during exercise at 60% of the pretraining VO(2)(peak) at 610 m and 30 degrees C. After the training, T(es) threshold for increasing FVC decreased in warm trials (P < 0.05) but not in cool trials and was significantly lower in HW than in cool trials (P < 0.05). The slope of FVC increase/T(es) increase increased in all trials (P < 0.05) except for high-altitude cool (P > 0.4) and was significantly higher in HW than in cool trials (P < 0.05). Thus, against our hypothesis, the VO(2)(peak) for HW did not increase more than in other trials. Moreover, slope of FVC increase/T(es) increase in HW increased most, despite the similar increase in blood volume, suggesting that factors other than blood volume were involved in the highest FVC response in HW.


Assuntos
Altitude , Regulação da Temperatura Corporal/fisiologia , Meio Ambiente , Resistência Física/fisiologia , Aptidão Física/fisiologia , Adulto , Limiar Anaeróbio/fisiologia , Volume Sanguíneo/fisiologia , Exercício Físico/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Pele/irrigação sanguínea , Temperatura , Vasodilatação/fisiologia , Capacidade Vital/fisiologia
8.
J Appl Physiol (1985) ; 89(6): 2196-205, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11090568

RESUMO

This study assessed the hypothesis that increasing cardiac filling pressure (CFP) would enhance contracting muscle blood flow (MBF) by stretching cardiopulmonary baroreceptors and attenuate the increase in plasma lactate concentration ([Lac(-)](p)) during dynamic exercise. Continuous negative-pressure breathing (CNPB) (-15 cmH(2)O) was used to increase the CFP by accelerating the venous return to the heart. In the first series of experiments, 10 men performed a graded exercise seated on a cycle ergometer with (N1) and without CNPB (C1). The increase in [Lac(-)](p) for N1 was attenuated at 60%, 90%, and 100% of maximal exercise intensity compared with that in C1 (P < 0.001). Also, the increases in mean arterial pressure (MAP) and plasma catecholamine concentrations were attenuated in N1 compared with those in C1 throughout the graded exercise (P < 0.05). However, heart rate and pulse pressure were not significantly influenced by CNPB. Second, we studied the impact of CNPB on forearm MBF during a rhythmic handgrip exercise in 5 of the 10 subjects. Forearm MBF was measured immediately after cessation of the exercise by venous occlusion plethysmography at rest, 30%, 50%, and 70% of maximal work load (WL(max)) with (N2) and without CNPB (C2). Forearm MBF and vascular conductance for both trials increased with the increase in intensity, but forearm skin blood flow measured by laser-Doppler flowmetry remained unchanged. MBF and vascular conductance in N2, however, increased more than in C2 at every intensity (P < 0.01) except for MBF at 70% WL(max), whereas the increase in MAP for N2 was attenuated compared with that in C2 (P < 0.05). Thus augmented active muscle vasodilation occurred in N2 with a lower increase in MAP compared with that in C2. These findings suggest that the stretch of intrathoracic baroreceptors, such as cardiopulmonary mechanoreceptors, by CNPB increased MBF by suppressing sympathetic nerve activity. The attenuation of the increase in [Lac(-)](p) might be caused, at least partially, by the increased MBF.


Assuntos
Exercício Físico/fisiologia , Ácido Láctico/sangue , Músculo Esquelético/irrigação sanguínea , Respiradores de Pressão Negativa , Adulto , Pressão Sanguínea/fisiologia , Circulação Coronária/fisiologia , Teste de Esforço , Antebraço , Humanos , Masculino , Concentração Osmolar , Fluxo Sanguíneo Regional/fisiologia , Resistência Vascular , Vasodilatação/fisiologia
9.
Am J Physiol Regul Integr Comp Physiol ; 279(1): R161-8, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10896878

RESUMO

To test the hypothesis that acute hypoxia does not modify the relationship between plasma vasopressin concentration ([AVP](p)) and plasma osmolality (P(osmol)) during exercise and that the increase in [AVP](p) during exercise is due mainly to the exercise intensity-dependent increase in P(osmol), we examined [AVP](p) during a graded exercise in a hypoxic condition (13% O(2), N(2) balance) in seven healthy male subjects. A graded exercise in a normoxic condition on a separate day served as the control. Hypoxia reduced peak aerobic power (VO(2 peak)) by 32.4 +/- 2.7%. Blood samples obtained during rest and at around 25, 45, 65, 80, and 100% of VO(2 peak) of each of the respective conditions were used for analyses of intravascular water and electrolyte balance. The pattern of the changes in fluid and electrolyte balance in response to percent VO(2 peak) was similar between the two conditions. Plasma volume decreased linearly as percent VO(2 peak) increased while P(osmol) increased in a curvilinear fashion with a steep increase occurring at above approximately 66% VO(2 peak). Above this relative exercise intensity, plasma sodium, potassium, and lactate concentrations also increased, whereas plasma bicarbonate concentration decreased. Thus transvascular fluid movement at above approximately 66% VO(2 peak) was due to the net efflux of hypotonic fluid out of the vascular space in both conditions. The relationship between [AVP](p) and P(osmol) during exercise in response to relative exercise intensity was similar between the two conditions. The results indicate that acute mild hypoxia itself has no direct effect on vasopressin release, and it does not modify the relationship between [AVP](p) and P(osmol) during exercise. The results also support the hypothesis that exercise-induced vasopressin release is primarily stimulated by increased P(osmol) produced by hypotonic fluid movement out of the vascular space in a relative exercise intensity-dependent manner.


Assuntos
Arginina Vasopressina/metabolismo , Água Corporal/metabolismo , Hipóxia/metabolismo , Esforço Físico/fisiologia , Volume Plasmático/fisiologia , Doença Aguda , Adulto , Gasometria , Pressão Sanguínea/fisiologia , Peso Corporal/fisiologia , Eletrólitos/sangue , Frequência Cardíaca/fisiologia , Humanos , Ácido Láctico/sangue , Masculino , Concentração Osmolar
10.
J Antibiot (Tokyo) ; 53(1): 33-7, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10724005

RESUMO

Two novel antifungal antibiotics, PF1163A and B, were isolated from the fermentation broth of Penicillium sp. They were purified from the solid cultures of rice media using ethyl acetate extraction, silica gel and Sephadex LH-20 column chromatographies. PF1163A and B showed potent growth inhibitory activity against pathogenic fungal strain Candida albicans but did not show cytotoxic activity against mammalian cells. These compounds inhibited the ergosterol biosynthesis in Candida albicans.


Assuntos
Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/metabolismo , Ergosterol/biossíntese , Fermentação , Humanos , Compostos Macrocíclicos , Testes de Sensibilidade Microbiana , Penicillium , Células Tumorais Cultivadas/efeitos dos fármacos
11.
J Antibiot (Tokyo) ; 53(1): 38-44, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10724006

RESUMO

The structures of new antifungal antibiotics, PF1163A and B, were elucidated by spectroscopic analyses of the degradation products and by X-ray crystallography of the de-2-hydroxyethyl derivative of PF1163B. Both antibiotics consist of a 13-membered macrocyclic structure containing a derivative of N-methyl tyrosine and a hydroxy fatty acid. PF1163A differs from PF 1163B by having an additional hydroxyl group on the side chain.


Assuntos
Antifúngicos/química , Compostos Macrocíclicos , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Penicillium , Estereoisomerismo
12.
Jpn J Physiol ; 49(1): 121-4, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10219117

RESUMO

Tail skin blood flow (TBFu) was directly measured in anesthetized and passively heated rats by ultrasonic Doppler flowmetry during heating, and the values were compared to those (TBFp) simultaneously measured by venous-occlusion plethysmography. TBFp was estimated from the values per unit tissue multiplied by the tail volume, the shape of which was assumed to be a cone. TBFp was highly correlated with TBFu, with a regression equation of TBFp = 0.7TBFu+0.1 (r2 = 0. 94, p<0.001). Although TBFp was slightly lower than TBFu, the equation is useful to estimate the absolute values of tail skin blood flow from the values of plethysmography in awake rats.


Assuntos
Fluxometria por Laser-Doppler , Pletismografia , Fluxo Sanguíneo Regional , Pele/irrigação sanguínea , Anestesia , Animais , Ratos , Cauda
13.
Hepatogastroenterology ; 46(30): 3244-8, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10626195

RESUMO

BACKGROUND/AIMS: The prognosis of patients with advanced pancreatic cancer is extremely poor. To improve their prognosis, providing effective chemotherapy is necessary. The aim of this study was to evaluate the anti-tumor activity and toxicity of combined chemotherapy (FP therapy) using 5-fluorouracil and cisplatin in Japanese chemo-naive patients with advanced pancreatic cancer. METHODOLOGY: Thirty-seven previously untreated patients with histologically proven pancreatic adenocarcinoma were treated with FP therapy. 5-fluorouracil was administered at 500 mg/m2/day by continuous intravenous infusion for 5 days and cisplatin was administered at 80 mg/m2 intravenously on the 1st day. Therapy was repeated every 4 weeks until there was evidence of disease progression or unacceptable toxicity. RESULTS: Three patients achieved partial responses, whereas none exhibited a complete response. The overall response rate was 8% (95% confidence interval, 2-22%) and the response durations were 6, 9 and 12 months, respectively. The median survival time of patients was 5 months. Toxicities were generally mild and acceptable, although nausea/vomiting was the most commonly observed toxicity. CONCLUSIONS: FP therapy on this schedule had limited anti-tumor activity for pancreatic cancer, indicating that, practically, it should not be performed in Japanese patients with advanced pancreatic cancer.


Assuntos
Adenocarcinoma/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Cisplatino/administração & dosagem , Fluoruracila/administração & dosagem , Neoplasias Pancreáticas/tratamento farmacológico , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Adolescente , Adulto , Idoso , Biópsia por Agulha , Progressão da Doença , Feminino , Humanos , Infusões Intravenosas , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Neoplasias Pancreáticas/mortalidade , Neoplasias Pancreáticas/patologia , Taxa de Sobrevida , Resultado do Tratamento
14.
Am J Physiol ; 275(5): R1703-11, 1998 11.
Artigo em Inglês | MEDLINE | ID: mdl-9791093

RESUMO

To gain better insights into the effect of dehydration on thermal and cardiovascular regulation during hyperthermia, we examined these regulatory responses during body heating in rats under isosmotic hypovolemia and hyperosmotic hypovolemia. Rats were divided into four groups: normovolemic and isosmotic (C), hypovolemic and isosmotic [L, plasma volume loss (DeltaPV) = -20% of control], hypovolemic and less hyperosmotic [HL1, increase in plasma osmolality (DeltaPosm) = 23 mosmol/kgH2O, DeltaPV = -16%], and hypovolemic and more hyperosmotic (HL2, DeltaPosm = 52 mosmol/kgH2O, DeltaPV = -17%). Hyperosmolality was attained by subcutaneous injection of hypertonic saline and hypovolemia by intra-arterial injection of furosemide before heating. Then rats were placed in a thermocontrolled box (35 degreesC air temperature, approximately 20% relative humidity) for 1-2 h until rectal temperatures (Tre) reached 40.0 degreesC. Mean arterial pressure in L decreased with rise in Tre (P < 0.001), whereas mean arterial pressure remained constant in the other groups. Maximal tail skin blood flow in L, HL1, and HL2 was decreased to approximately 30% of that in C (P < 0. 001). Tre threshold for tail skin vasodilation (TVD) was not changed in L, whereas the threshold shifted higher in the HL groups. Tre threshold for TVD was highly correlated with Posm (r = 0.94, P < 0. 001). Heart rate in the HL groups increased with rise in Tre (P < 0. 001), whereas it remained unchanged in C and L. Cardiovascular responses to heating were not influenced by V1 antagonist in C, L, and HL2. Thus isotonic hypovolemia attenuates maximal tail skin blood flow, whereas hypertonic hypovolemia causes an upward shift of Tre threshold for TVD and an increase in heart rate during hyperthermia. These results suggest that plasma hyperosmolality stimulates pressor responses in the hypovolemic condition that subsequently contribute to arterial pressure regulation during heat stress.


Assuntos
Pressão Sanguínea/fisiologia , Desidratação/sangue , Desidratação/fisiopatologia , Equilíbrio Hidroeletrolítico/fisiologia , Animais , Calefação , Masculino , Ratos , Ratos Wistar
15.
Am J Physiol ; 275(1): R286-90, 1998 07.
Artigo em Inglês | MEDLINE | ID: mdl-9688990

RESUMO

To elucidate the role of increased plasma osmolality (Posmol), which occurs during exercise in the regulation of cutaneous vasodilation (CVD) during exercise, we determined the relationship between the change in esophageal temperature (DeltaTes) required to elicit CVD (DeltaTes threshold for CVD) and Posmol during light and moderate exercise (30 and 55% of peak oxygen consumption, respectively) and passive body heating. Then we compared the relationship with the data obtained in our previous study [A. Takamata, K. Nagashima, H. Nose, and T. Morimoto. Am. J. Physiol. 273 (Regulatory Integrative Comp. Physiol. 42): R197-R204, 1997], in which we determined the relationships during passive body heating following isotonic (0.9% NaCl) or hypertonic (2 or 3% NaCl) saline infusions in the same subjects. Posmol values at 5 min after the onset of exercise were 287.5 +/- 0.9 mosmol/kgH2O during light exercise and 293.0 +/- 1.2 mosmol/kgH2O during moderate exercise. Posmol just before passive body heating was 289.9 +/- 1.4 mosmol/kgH2O. The DeltaTes threshold for CVD was 0.09 +/- 0.05 degrees C during light exercise, 0.31 +/- 0. 09 degrees C during moderate exercise, and 0.10 +/- 0.05 degrees C during passive body heating. The relationship between the DeltaTes threshold for CVD and Posmol was shown to be on the same regression line both during exercise and during passive body heating with or without infusions [A. Takamata, K. Nagashima, H. Nose, and T. Morimoto. Am. J. Physiol. 273 (Regulatory Integrative Comp. Physiol. 42): R197-R204, 1997]. Our data suggest that the elevated body core temperature threshold for CVD during exercise could be the result of increased Posmol induced by exercise and is not due to reduced plasma volume or the intensity of the exercise itself.


Assuntos
Regulação da Temperatura Corporal , Temperatura Corporal , Exercício Físico/fisiologia , Esforço Físico/fisiologia , Pele/irrigação sanguínea , Vasodilatação/fisiologia , Adulto , Esôfago , Temperatura Alta , Humanos , Masculino , Concentração Osmolar , Consumo de Oxigênio , Fluxo Sanguíneo Regional
16.
J Appl Physiol (1985) ; 84(6): 1845-51, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9609775

RESUMO

To assess the impact of continuous negative-pressure breathing (CNPB) on the regulation of skin blood flow, we measured forearm blood flow (FBF) by venous-occlusion plethysmography and laser-Doppler flow (LDF) at the anterior chest during exercise in a hot environment (ambient temperature = 30 degreesC, relative humidity = approximately 30%). Seven male subjects exercised in the upright position at an intensity of 60% peak oxygen consumption rate for 40 min with and without CNPB after 20 min of exercise. The esophageal temperature (Tes) in both conditions increased to 38.1 degreesC by the end of exercise, without any significant differences between the two trials. Mean arterial pressure (MAP) increased by approximately 15 mmHg by 8 min of exercise, without any significant difference between the two trials before CNPB. However, CNPB reduced MAP by approximately 10 mmHg after 24 min of exercise (P < 0.05). The increase in FBF and LDF in the control condition leveled off after 18 min of exercise above a Tes of 37.7 degreesC, whereas in the CNPB trial the increase continued, with a rise in Tes despite the decrease in MAP. These results suggest that CNPB enhances vasodilation of skin above a Tes of approximately 38 degrees C by stretching intrathoracic baroreceptors such as cardiopulmonary baroreceptors.


Assuntos
Exercício Físico/fisiologia , Temperatura Alta , Respiração Artificial , Pele/irrigação sanguínea , Respiradores de Pressão Negativa , Adulto , Gasometria , Pressão Sanguínea/fisiologia , Antebraço/irrigação sanguínea , Antebraço/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Fluxo Sanguíneo Regional/fisiologia
18.
Med Sci Sports Exerc ; 29(7): 867-73, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9243485

RESUMO

To clarify the relationship between aerobic power (VO2max), blood volume (BV), and thermoregulatory responses to exercise-heat stress, we analyzed the cross-sectional relationship between the resting BV, plasma volume (PV), erythrocyte volume (EV), VO2max, forearm blood flow (FBF), and sweating responses during exercise in a hot environment (31 degrees C, 50% relative humidity). Twelve college-aged male subjects with a mean maximal oxygen uptake of 48 (range 42-59) mL.kg-1.min-1, a mean PV of 54 (range 42-72) mL.kg-1, a mean EV of 31 (range 23-43) mL.kg-1, and a mean BV of 85 (range 67-115) mL.kg-1 (measured by the Evans Blue dye dilution method) performed three sessions of 20-min cycle exercise at two levels of intensity (40% and 60% VO2max). The BV, PV and EV correlated positively with peak FBF (r = 0.596-0.711, P < 0.05), the increase of FBF in response to a unit rise in esophageal temperature (Tes; peak delta FBF/peak delta Tes) (r = 0.592-0.656, P < 0.05) and with total sweat loss (TSL) (r = 0.599-0.634, P < 0.05) during the exercise. The VO2max correlated with TSL during exercise at 40% VO2max (r = 0.578, P < 0.05), but not with peak FBF and peak delta FBF/peak delta Tes. The VO2max per lean body mass also showed a significant positive correlation with BV (r = 0.769, P < 0.01), PV (r = 0.706, P < 0.05), and with EV (r = 0.841, P < 0.001). The peak delta FBF/peak delta Tes was correlated positively with peak FBF (r = 0.597-0.830, P < 0.05-0.01) and negatively with peak Tes (r = 0.641-0.769, P < 0.05-0.01) during the exercise at the two levels. However, the chest sweat rate (CSR), TSL, and the increase of CSR in response to a unit rise in Tes (peak delta CSR/peak delta Tes) showed no correlation with peak Tes during the exercise at the two levels. These findings suggest that 1) heat dissipation responses during exercise were related more to blood volume than aerobic power and 2) skin blood flow was related more to body temperature than sweating responses during exercise under mild heat stress.


Assuntos
Volume Sanguíneo , Regulação da Temperatura Corporal/fisiologia , Exercício Físico/fisiologia , Transtornos de Estresse por Calor/fisiopatologia , Adolescente , Adulto , Temperatura Corporal/fisiologia , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Resistência Física/fisiologia
19.
Am J Physiol ; 273(1 Pt 2): R197-204, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9249550

RESUMO

We examined the effect of increased plasma osmolality (P(osm)) on cutaneous vasodilatory response to increased esophageal temperature (T(es)) in passively heated human subjects (n = 6). To modify P(osm), subjects were infused with 0.9, 2, or 3% NaCl infusions (Inf) for 90 min on separate days. Infusion rates were 0.2, 0.15, and 0.125 ml.min-1.kg body wt-1 for 0.9, 2, and 3% Inf, respectively, which produced relatively similar plasma volume expansion. Thirty minutes after the end of infusion, subjects immersed their lower legs in a water bath at 42 degrees C (room temperature 28 degrees C) for 60 min after 10 min of preheating control measurements. Passive heating without infusion (NI) served as time control to account for the effect of volume expansion. P(osm) (mosmol/kgH2O) values at the onset of passive heating were 289.9 +/- 1.4, 292.1 +/- 0.6, 298.7 +/- 0.7, and 305.6 +/- 0.6 after NI, 0.9% Inf, 2% Inf, and 3% Inf, respectively. The increases in T(es) (delta T(es)) at equilibrium during passive heating (mean delta T(es) during 55-60 min) were 0.47 +/- 0.08, 0.59 +/- 0.08, 0.85 +/- 0.13, and 1.09 +/- 0.12 degrees C after NI, 0.9% Inf, 2% Inf, and 3% Inf, respectively, which indicates that T(es) at equilibrium increased linearly as P(osm) increased. delta T(es) required to elicit cutaneous vasodilation (delta T(es) threshold for cutaneous vasodilation) also increased linearly as P(osm) increased as well as the delta T(es) threshold for sweating. The calculated increases in these thresholds per unit rise in P(osm) from regression analysis were 0.044 degree C for the cutaneous vasodilation and 0.034 degree C for sweating. Thus the delta T(es) thresholds for cutaneous vasodilation and sweating are shifted to higher delta T(es) along with the increase in P(osm), and these shifts resulted in the higher increase in T(es) during passive heating.


Assuntos
Regulação da Temperatura Corporal , Pele/irrigação sanguínea , Vasodilatação , Equilíbrio Hidroeletrolítico , Adulto , Pressão Sanguínea , Temperatura Corporal , Esôfago , Frequência Cardíaca , Temperatura Alta , Humanos , Infusões Intravenosas , Masculino , Fluxo Sanguíneo Regional , Análise de Regressão , Solução Salina Hipertônica/administração & dosagem , Solução Salina Hipertônica/farmacologia , Sudorese/fisiologia , Fatores de Tempo , Equilíbrio Hidroeletrolítico/efeitos dos fármacos
20.
Cancer ; 79(8): 1516-20, 1997 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-9118032

RESUMO

BACKGROUND: Radiotherapy plus bolus 5-fluorouracil (5-FU) is generally accepted as the standard treatment for locally advanced pancreatic carcinoma. To intensify the antitumor effect of chemotherapy, the authors administered protracted 5-FU infusion with concurrent radiotherapy. The aim of this study was to determine the feasibility and effectiveness of this combined therapy. METHODS: Twenty patients, all of whom had histologically confirmed exocrine pancreatic carcinoma that was nonresectable but confined to the pancreatic region, were enrolled in a Phase II trial of protracted 5-fluorouracil infusion (200 mg/m2/day) with concurrent radiotherapy (50.4 gray in 28 fractions over 5.5 weeks). Chemotherapy began on the first day of radiation and continued through the entire radiation course. Thereafter, weekly infusions (500 mg/m2) were administered until disease progression. RESULTS: Of the 20 patients, 17 (85%) completed the scheduled course of chemoradiotherapy. Grade 3 or worse toxicity, graded according to World Health Organization criteria, was observed in 4 patients (20%). Two patients (10%) achieved partial response, and disease remained stable in 16 patients (80%). After the completion of combined therapy, serum CA 19-9 levels were reduced by more than 50% in 10 of 12 patients (83%) who had pretreatment CA 19-9 levels of 100 U/mL or greater. The median progression free survival and 1-year progression free survival rate were 4.9 months and 29.5%, respectively. The median overall survival and 1-year overall survival rate were 10.3 months and 41.8%, respectively. CONCLUSIONS: This treatment showed moderate activity against locally advanced pancreatic carcinoma and was accompanied by an acceptable toxicity level.


Assuntos
Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/radioterapia , Antimetabólitos Antineoplásicos/uso terapêutico , Fluoruracila/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/radioterapia , Adenocarcinoma/patologia , Adulto , Idoso , Antimetabólitos Antineoplásicos/efeitos adversos , Terapia Combinada , Progressão da Doença , Estudos de Viabilidade , Feminino , Fluoruracila/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Pancreáticas/patologia , Dosagem Radioterapêutica
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