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1.
Artigo em Inglês | MEDLINE | ID: mdl-38287653

RESUMO

The pulp and paper industry stands out as an example of a technology based on a renewable resource, cellulose. The sludge, however, poses major environmental and public health problems. To effectively manage the sludge wastes, it is critical to fully evaluate its composition, possible environmental impacts, and the total amount of exploitable renewable resources. The study established the pH of the sludge to be 7.32 ± 0.98, an electrical conductivity (1.84 mS/cm), nitrogen concentration (2.65 ± 0.21%), and total organic matter (41.23 ± 3.11%). The cellulosic content was established to be 74.07 ± 2.71% which contributes to 53.07 ± 1.23% water holding capacity (WHC). The most abundant elements were C and O, followed by Cl, Si, Al, and Mg, with lower concentrations of S, Si, K, and iron. The polycyclic aromatic compounds (PAHs) levels ranged from 0.29 to 322.56 ng.g-1 with 1-methyl pyrene posting the highest concentration (322.56 ng.g-1. XRD peaks at 17.10°, 23.86°, 30.14°, and 36.57°, which imply the existence of CaCO3. SEM indicated that the sludge was majorly comprised of fibers materials with average particle sizes of 280 micrometers. TGA/DTG analysis showed that the sludge had the greatest cellulose and hemicellulose (64.7 wt. %).


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Esgotos , Celulose , Estudos de Viabilidade , Hidrocarbonetos Policíclicos Aromáticos/análise , Reciclagem
2.
Atherosclerosis ; 75(2-3): 111-22, 1989 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2712856

RESUMO

The relationship between serologic predictors of coronary risk and anthropometric as well as lifestyle characteristics was investigated in 61 men (37.5 +/- 8.5 yrs) and 33 women (40.1 +/- 9.0 yrs). All subjects were healthy non-smokers, mostly middle-class bank employees. In bivariate analysis, among both genders the ratio of waist-to-hip circumference (WHR) was the single best predictor of levels of serum LDL-cholesterol, apolipoprotein B, VLDL-cholesterol and triglycerides (positive association) as well as HDL-cholesterol and apolipoprotein A-I (inverse association). In men, body fat as estimated from bioelectrical impedance measurement was the second best predictor of lipoprotein and apoprotein concentrations, whereas in women it was the body mass index (BMI). The additional independent predictive power of WHR and body fat for the lipid profile was tested in multivariate analysis by adding WHR and body fat sequentially to regression models containing already BMI, endurance capacity, exercise, alcohol consumption and age. For example, explained variance of triglyceride distribution rose from 26.3 to 35.1% (P = 0.01 for increase) when body fat was entered into the regression equation, or inclusion of WHR into a model already containing age, the behavioral variables, BMI, and body fat increased the explained variance of LDL/HDL-cholesterol ratio from 20.9 to 27.6% (P = 0.04 for increase). In women, the same regression models were even slightly more predictive for the serum lipid profile. Endurance capacity was related to a low atherogenic risk lipid profile in bivariate analysis but lost much of its predictive power in multivariate analysis, which confirms that the effect of fitness on lipid levels is probably mediated in part by a low body fat content. It is concluded from this cross-sectional investigation that studies which focus on associations between lifestyle and serologic predictors of atherogenic risk should possibly include the WHR and a measure of body fat, since the latter two appear to be closer correlates of serum lipoprotein and apolipoprotein levels than BMI or single behavioral factors, at least among male non-smokers.


Assuntos
Antropometria , Apolipoproteínas/sangue , Estilo de Vida , Lipoproteínas/sangue , Tecido Adiposo/fisiologia , Adulto , Fatores Etários , Consumo de Bebidas Alcoólicas , Colesterol/sangue , Exercício Físico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resistência Física , Fatores Sexuais , Estatística como Assunto
3.
Atherosclerosis ; 81(1): 19-31, 1990 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2407251

RESUMO

To study the effects of long-term, self-monitored exercise on the serum lipid profile and body composition of middle-aged non-smoking males, a controlled study was conducted in 61 sedentary, middle-class Swiss men. Thirty-nine men were randomly allocated to jog 2 h/wk for 4 months on an individually prescribed, heart rate-controlled basis, whereas 22 men served as controls. Despite varying adherence to the exercise regimen, the following 4-month net changes (effect in exercise group minus effect in control group) in lipids were seen: HDL cholesterol (C) +0.12 mmol/l (95% CI 0.02, 0.22; P = 0.028), LDL-C +0.08 mmol/l (ns), VLDL-C -0.26 mmol/l (-0.45, -0.07; P = 0.009), total triglycerides (TT) -0.21 mmol/l (ns), HDL-C/total C +0.02 (0.001, 0.05; P = 0.047). The net changes in endurance capacity and resting heart rate in favour of exercisers were significant as well, whereas no significant changes in apolipoprotein levels were seen. Exploratory analyses revealed, for example, associations of the increase in total physical activity with an increase in the HDL-C/total C ratio (r = 0.46; P less than 0.001), and of the change in estimated body fat content with an opposed change in the HDL-C/total C ratio (r = -0.40; P less than 0.001), or an inverse relationship of the change in subcutaneous fat with a change in the HDL2-C level (r = -0.39; P less than 0.001). Multivariable regression analysis suggested that much of the effect of jogging on HDL-C was apparently mediated through a decrease in body fat content. A change in the waist/hip ratio was unrelated to lipoprotein changes but was related to the change of TT level (r = 0.22; P less than 0.05). This study confirms that individually prescribed, unsupervised jogging can increase HDL-C levels and improve the serum lipoprotein profile in self-selected nonsmoking males. Although the effect is modest, it may be relevant to preventive cardiology, given the evidence for a reduction in cardiovascular risk even after apparently small decreases in risk factor levels.


Assuntos
Apolipoproteínas/sangue , Exercício Físico , Lipoproteínas/sangue , Fatores Etários , Humanos , Metabolismo dos Lipídeos , Masculino , Pessoa de Meia-Idade
4.
Ann Epidemiol ; 4(5): 375-81, 1994 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-7981845

RESUMO

The present study compared the different health effects of 6 months' endurance training at two exercise intensities. Seventy-five nonsmoking, sedentary men were randomly assigned to either a home-based, unsupervised exercise program of 4 x 30 min/wk jogging at an intensity of 75% VO2max (n = 28), or of 6 x 30 min/wk walking at an intensity of 50% VO2max (n = 28), or to an inactive control group (n = 19). Exercise adherence and injuries related to exercise training as well as changes in endurance capacity, body fat, and serum lipids were assessed. After 6 months, joggers and walkers showed a similar increase in VO2max as measured by a maximal bicycle ergometer test (2.9 +/- 4.1 ml/kg min, P < 0.01 and 2.5 +/- 5.7 ml/kg min, P < 0.5, respectively). There were no significant changes in blood lipids in either group, although results revealed a significant association between the amount of training (i.e., kilometers exercised) and the increase in high-density lipoprotein-cholesterol (HDL-C) in joggers (Pearson's r = 0.42, P < 0.05). In walkers, a significant association between the amount of exercise and the decrease in sum of skinfolds and the waist-hip ratio was observed (Pearson's r = -0.48 and -0.45, P < 0.05 for both). The adherence rate was similar for both training groups with respect to the prescribed intervention goal with an average of 90 +/- 41 min/wk (joggers) and 121 +/- 72 min/wk (walkers) spent on endurance training.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Saúde , Corrida Moderada , Caminhada , Tecido Adiposo , Adulto , Antropometria , HDL-Colesterol/sangue , Humanos , Corrida Moderada/lesões , Masculino , Pessoa de Meia-Idade , Resistência Física
5.
J Appl Physiol (1985) ; 90(3): 1036-40, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11181617

RESUMO

Application of a supramaximal electrical twitch to the voluntarily contracted muscle is used to assess the level of muscle activation. Large variability in the interpolated twitch torque (ITT) has been observed when repeated stimulations are performed. It is hypothesized that this variability in ITT is caused by the stochastic nature of the timing of twitch application relative to pulses of voluntary excitation trains. Two experiments were performed on 12 subjects each to test this hypothesis. For the first experiment, a single twitch was superimposed on a train stimulation at different time intervals relative to the train pulses. For the second experiment, single, double, triple, or quadruple twitches were applied on a voluntarily contracted muscle. The ITT critically depended on the time point of twitch application: a single pulse applied 5 ms before a train pulse consistently evoked higher ITTs than all other stimulation conditions. Furthermore, variability of the ITT decreased as the number of applied twitches increased. The results support the hypothesis that a large part of the variability in the ITT may be caused by the timing of the superimposed twitch relative to the motor unit trains. The variability may be reduced by increasing the number of superimposed twitches.


Assuntos
Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Adulto , Estimulação Elétrica , Feminino , Nervo Femoral/fisiologia , Humanos , Contração Isométrica/fisiologia , Articulação do Joelho/fisiologia , Masculino , Músculo Esquelético/inervação , Processos Estocásticos , Nervo Tibial/fisiologia , Fatores de Tempo , Torque
6.
J Appl Physiol (1985) ; 87(5): 1651-5, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10562604

RESUMO

The purpose of this study was to investigate whether the isometric muscle force, redeveloped following maximal-effort voluntary shortening contractions in human skeletal muscle, is smaller than the purely isometric muscle force at the corresponding length. Isometric knee extensor moments, surface electromyographic (EMG) signals of quadriceps femoris, and interpolated twitch moments (ITMs) were measured while 10 subjects performed purely isometric knee extensor contractions at a 60 degrees knee angle and isometric knee extensor contractions at a 60 degrees knee angle preceded by maximal-effort voluntary shortening of the quadriceps muscles. It was found that the knee extensor moments were significantly decreased for the isometric-shortening-isometric contractions compared with the isometric contractions for the group as a whole, whereas the corresponding EMG and ITM values were the same. This study is the first to demonstrate force depression following muscle shortening for voluntary contractions. We concluded that force depression following muscle shortening is an actual property of skeletal muscle rather than a stimulation artifact and that force depression during voluntary contraction is not accompanied by systematic changes in muscle activation as evaluated by EMG and ITM.


Assuntos
Músculo Esquelético/fisiologia , Adulto , Eletromiografia , Feminino , Humanos , Contração Isométrica/fisiologia , Joelho/fisiologia , Masculino , Contração Muscular/fisiologia
7.
Acad Med ; 73(9): 948-55, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9759096

RESUMO

From 1991 to 1996, the faculty at the University of Florida College of Medicine initiated several significant changes in its curriculum. These changes, included the introduction of early clinical experience in primary care settings; the enhancement of active learning experiences in small-group settings; production and use of computer-based interactive learning materials; increased clinical teaching in the ambulatory care training in an interdisciplinary primary care clerkship; effective course and faculty evaluation; establishment and use of an assessment center for instruction and performance-based evaluations utilizing standardized patients; creation of a medical education center as the focal point for logistics support of the teaching faculty and education data handling; creation of a faculty development program; and initiation of mission-based budgeting based on the faculty's teaching effort and quality. Because the faculty were relatively conservative, it was important to identify variables that would facilitate the introduction of changes and those that might hinder it. The following factors were most important: interest and support by the dean and clearly defined delegation of authority to an associate dean; introduction of a mission-based budgeting process that allocates education funds on the basis of faculty teaching effort and its quality; a clear understanding of the empowerment of the curriculum committee; and an identification of the principles that should guide educational planning and implementation. These efforts are considered the beginning of the continuous renewal needed to respond to information networking, scientific and technological innovations, and the fundamental changes in health care delivery. As these changes have taken place, a shift toward greater institutional control of the educational program leading to the MD degree has been evident.


Assuntos
Currículo , Educação Médica , Atitude , Estágio Clínico , Docentes de Medicina , Florida , Liderança , Objetivos Organizacionais
8.
Med Sci Sports Exerc ; 25(6): 748-54, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8321114

RESUMO

The relationship between risk factors for CHD such as physical activity, cardiovascular fitness, subcutaneous body fat, dietary intake characteristics, age, and sex with the blood lipid profile was examined in 39 boys and 58 girls aged 10-15 yr. In boys, a high level of physical activity was related to higher concentrations of HDL-C (r = 0.32, P < 0.05), as well as to lower concentrations of VLDL-C, total triglycerides (TG), and the ratio of total cholesterol (TC) to HDL-C (r = -0.42; -0.40, both P < 0.01; and -0.37, P < 0.05). A high sum of 10 skinfolds (sigma 10SF) was related to a higher ratio of TC/HDL-C (r = 0.35; P < 0.05). In girls, physical activity was positively related to HDL-C (r = 0.29; P < 0.05). The sigma 10SF showed a negative association with Apo A-I and HDL-C (r = -0.26, -0.29, both P < 0.05) and a positive association with apolipoprotein B (Apo B) (r = 0.28, P < 0.05). Cardiovascular fitness was not significantly related to any of the blood lipid concentrations, in either boys or girls. Intake of saturated fats and dietary cholesterol was positively related to TC levels in boys, but the associations failed to reach statistical significance (r = 0.34 and r = 0.31, P > 0.05) due to the small sample size (N = 32).(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Tecido Adiposo/anatomia & histologia , Composição Corporal , Dieta , Lipídeos/sangue , Atividade Motora/fisiologia , Aptidão Física , Adolescente , Fatores Etários , Apolipoproteínas A/análise , Índice de Massa Corporal , Criança , Colesterol/sangue , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Estudos Transversais , Metabolismo Energético , Teste de Esforço , Feminino , Humanos , Masculino , Aptidão Física/fisiologia , Fatores Sexuais
9.
Med Sci Sports Exerc ; 25(3): 363-70, 1993 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8455452

RESUMO

The purpose of the present study was to derive a regression equation relating variables obtained from a series of noninvasive functional tests in a normal subject population to the fiber type distribution of vastus lateralis muscle (VL) determined using muscle biopsy. All functional tests were designed to distinguish between basic properties of Type II fibers (fast twitch fibers) and Type I fibers (slow twitch fibers) and included assessment of peak torque, power output at nine different angular velocities (60 degrees.s-1 to 300 degrees.s-1), as well as a fatigue test consisting of 60 consecutive contractions at 90 degrees.s-1 to establish fatigue resistance of the knee extensor muscles. Using a stepwise multiple regression procedure, relative torque after 53-55 contractions (T55) in the fatigue test and power output at an angular velocity of 280 degrees.s-1 normalized for fat free mass of the thigh (FFMT) were the best predictors for fiber type distribution, explaining 51.8% of the variance in the proportion of Type II fibers in VL. No other measured variable met entering criteria. Subgroup analyses revealed a higher peak torque/FFMT, higher power/FFMT values at angular velocities of 200 degrees.s-1 and higher, and lower relative torque beyond 30 contractions in the fatigue test for the fast twitch group, FTG (subjects with > 60% Type II fibers, N = 8) as compared with the STG (subjects with < 45% Type II fibers, N = 9). Results from the present study suggest that two simple functional tests on a Cybex dynamometer yield reasonable estimates of the fiber type distribution in VL.


Assuntos
Modelos Biológicos , Contração Muscular/fisiologia , Músculos/anatomia & histologia , Adulto , Análise de Variância , Fenômenos Biomecânicos , Composição Corporal , Feminino , Humanos , Contração Isométrica/fisiologia , Perna (Membro)/fisiologia , Masculino , Análise Multivariada , Músculos/fisiologia , Esforço Físico , Análise de Regressão
10.
J Biomech ; 33(8): 917-23, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10828321

RESUMO

The purpose of this study was to determine the influence of speed and distance of muscle shortening on the amount of force depression for voluntary contractions. Two experimental tests were performed. In the first test, subjects performed isometric knee extensor contractions following muscle shortening produced by isokinetic knee extensions over the range 25-50 degrees. In the second test, subjects performed isometric knee extensor contractions following muscle shortening produced by isokinetic knee extensions at two speeds: 20 and 240 degrees /s. Knee extensor moments, surface electromyographical (EMG) signals of quadriceps femoris, and interpolated twitch moments were measured during all contractions and were compared with the corresponding values obtained during purely isometric contractions. Force depression following muscle shortening for the voluntary contractions tested in this study did not depend on the distance or the speed of muscle shortening. These results are in contrast to the corresponding results in the literature obtained using artificial electrical stimulation in which force depression was always found to be directly related to the distance of shortening and inversely related to the speed of shortening. The difference in force depression as a function of the distance and speed of muscle shortening between voluntary and artificial electrical stimulation may be associated with changes in activation following the voluntary shortening contractions, whereas activation is controlled and constant in all artificial stimulation protocols.


Assuntos
Contração Muscular/fisiologia , Adulto , Fenômenos Biomecânicos , Estimulação Elétrica , Eletrodos , Eletrofisiologia , Nervo Femoral/fisiologia , Humanos , Contração Isométrica/fisiologia , Movimento/fisiologia , Músculo Esquelético/fisiologia
11.
J Biomech ; 31(6): 511-7, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9755035

RESUMO

Long-term changes in the three-dimensional external loading, hind limb kinematics and knee stability were assessed in an anterior cruciate ligament (ACL)-transected cat model of osteoarthritis (OA). Seven skeletally mature cats (mean mass 4.6+/-1.4 kg) were studied before ACL transection (ACLT) and at 1 and 3 weeks, and at 3, 6, 9 and 12 months following ACLT. One week following ACLT, significant changes from the normal locomotion pattern were observed: peak vertical and anterior posterior ground reaction forces were decreased, particularly the peak posterior forces in the early phase of stance. Furthermore, knee angles were reduced by about 15 degrees throughout the whole gait cycle, while ankle and hip angles were reduced at paw off in the experimental compared to the contralateral hind limbs. Ground reaction forces and hind limb kinematics recovered to near pre-surgical patterns over the one year period assessed. ACLT was also associated with an increased knee instability which improved over time. X-rays suggested that there was a continued degeneration in the experimental knee over the one year period; there was osteophyte formation at the joint margins and an increase in cartilage thickness throughout the joint. It was speculated that the more flexed knee angles and the reduced anterior-posterior ground reaction forces in the ACL-transected compared to the intact hind limb represent an adaptive strategy aimed at avoiding excessive anterior displacement of the tibia in the early phase of stance. The recovery of the locomotion pattern with time might be related to the corresponding improvement of knee stability.


Assuntos
Membro Posterior/fisiopatologia , Instabilidade Articular/fisiopatologia , Articulação do Joelho/fisiopatologia , Osteoartrite/fisiopatologia , Animais , Lesões do Ligamento Cruzado Anterior , Fenômenos Biomecânicos , Gatos , Instabilidade Articular/etiologia , Masculino , Osteoartrite/etiologia , Fatores de Tempo , Ferimentos Penetrantes/complicações
12.
J Biomech ; 31(12): 1137-45, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9882046

RESUMO

The purposes of this study were to determine the in situ functional and material properties of articular cartilage in an experimental model of joint injury, and to quantify the corresponding in situ joint contact mechanics. Experiments were performed in the anterior cruciate ligament (ACL) transected knee of the cat and the corresponding, intact contralateral knee, 16 weeks following intervention. Cartilage thickness, stiffness, effective Young's modulus, and permeability were measured and derived from six locations of the knee. The total contact area and peak pressures in the patellofemoral joint were obtained in situ using Fuji Pressensor film, and comparisons between experimental and contralateral joint were made for corresponding loading conditions. Total joint contact area and peak pressure were increased and decreased significantly (alpha=0.01), respectively, in the experimental compared to the contralateral joint. Articular cartilage thickness and stiffness were increased and decreased significantly (alpha=0.01), respectively, in the experimental compared to the contralateral joint in the four femoral and patellar test locations. Articular cartilage material properties (effective Young's modulus and permeability) were the same in the ACL-transected and intact joints. These results demonstrate for the first time the effect of changes in articular cartilage properties on the load transmission across a joint. They further demonstrate a substantial change in the joint contact mechanics within 16 weeks of ACL transection. The results were corroborated by theoretical analysis of the contact mechanics in the intact and ACL-transected knee using biphasic contact analysis and direct input of cartilage properties and joint surface geometry from the experimental animals. We conclude that the joint contact mechanics in the ACL-transected cat change within 16 weeks of experimental intervention.


Assuntos
Cartilagem Articular/fisiopatologia , Fêmur/fisiopatologia , Articulação do Joelho/fisiopatologia , Osteoartrite/fisiopatologia , Patela/fisiopatologia , Animais , Ligamento Cruzado Anterior/cirurgia , Fenômenos Biomecânicos , Cartilagem Articular/patologia , Gatos , Modelos Animais de Doenças , Elasticidade , Fêmur/patologia , Articulação do Joelho/patologia , Modelos Biológicos , Osteoartrite/patologia , Patela/patologia , Permeabilidade , Pressão , Estresse Mecânico
13.
Spine (Phila Pa 1976) ; 26(16): E361-6, 2001 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-11493865

RESUMO

STUDY DESIGN: Cross-sectional study of 25 male golfers with chronic low back pain and 16 healthy controls of similar age. OBJECTIVES: To assess the association between functional capacity of the back extensors and the quadriceps muscles. SUMMARY OF BACKGROUND DATA: Chronic low back pain has been shown to lead to changes in muscle activation patterns of the abdominals and the gluteus maximus. The effect of chronic low back pain on lower limb function has not been investigated. METHODS: Back extensor endurance was assessed by a Biering-Sørensen test; surface EMG was measured bilaterally on the erector spinae at T12 and L4--L5. Muscle inhibition in the quadriceps was assessed by applying an electrical twitch to the maximally contracted muscle. The associations between holding time, decrease in EMG median frequency (i.e., the slope of the regression line on median frequency vs. time), and muscle inhibition were compared for study participants with chronic low back pain and controls. RESULTS: Mean back extensor holding times were 88 +/- 30 seconds for study participants with chronic low back pain and 92 +/- 17 seconds for controls. Both groups showed bilaterally similar decreases in EMG median frequency at L4--L5 and T12; however, the slopes were significantly steeper at L4--L5 than T12. Study participants with chronic low back pain with poor back endurance had significantly higher muscle inhibition compared with study participants with chronic low back pain with good back endurance, whereas such an association was not evident in healthy controls. CONCLUSIONS: In golfers with chronic low back pain reduced back endurance was associated with significant inhibition of the knee extensors, indicating that this muscle group cannot be activated to a full extent. These findings suggest a possible association between back extensor fatigability and knee extensor dysfunction in male golfers with chronic low back pain.


Assuntos
Dorso/fisiopatologia , Fadiga/fisiopatologia , Joelho/fisiopatologia , Dor Lombar/fisiopatologia , Músculo Esquelético/fisiopatologia , Adulto , Doença Crônica , Estudos Transversais , Eletromiografia , Golfe/fisiologia , Humanos , Contração Isométrica/fisiologia , Masculino , Resistência Física/fisiologia
14.
J Antibiot (Tokyo) ; 29(6): 653-5, 1976 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-950320

RESUMO

CGP 9000, (7-[D-2-amino-2-(1,4-cyclohexadienyl)-acetamido]-3-methoxy-3-cephem-4-carboxylic acid), is a new broad-spectrum cephalosporin antibiotic. Its antibacterial activity in vitro (MIC) is similar, but its bactericidal efficacy superior to that of cephalexin and cephradine. Upon oral administration to mice infected with various bacteria, CGP 9000 is, in general, 2 to 7 times more effective than either cephalexin or cephradine.


Assuntos
Bactérias/efeitos dos fármacos , Cefalosporinas/farmacologia , Animais , Infecções Bacterianas/tratamento farmacológico , Cefalexina/farmacologia , Cefalexina/uso terapêutico , Cefalexina/toxicidade , Cefalosporinas/uso terapêutico , Cefalosporinas/toxicidade , Cefradina/farmacologia , Cefradina/uso terapêutico , Feminino , Dose Letal Mediana , Camundongos , Fatores de Tempo
15.
Phys Ther ; 79(1): 66-75, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9920192

RESUMO

BACKGROUND AND PURPOSE: The purpose of this case report is to describe the evaluation, treatment, and short-term outcome for an individual with chronic, progressively worsening instability of the knee during gait associated with anterior cruciate ligament (ACL) insufficiency. CASE DESCRIPTION: The patient was a 34-year-old man who sustained bilateral ACL injuries. Subsequently, an autograft reconstruction of the left knee ACL was performed. Eight months post-reconstruction, the left knee was unstable despite bracing. Gait analysis and tests to determine the presence of muscle inhibition were performed prior to and after 12 weeks of training. Isometric torque of the knee extensors and flexors was measured with the knee in 90 degrees of flexion. A training program primarily consisted of electromyographic biofeedback during thigh muscle exercises, balance exercises, and gait. OUTCOMES: Muscle inhibition decreased and maximal isometric knee flexion and extension torques increased during the 12-week training period. Gait analysis demonstrated a 50% decrease in the maximum knee extensor moment and an increase in walking speed. DISCUSSION: Selected gait variables, torque production, and muscle inhibition may change in a person with an unstable knee. The measurement of variables that have previously been documented as mechanisms of knee instability during walking allows for the selection of a specific treatment approach.


Assuntos
Lesões do Ligamento Cruzado Anterior , Terapia por Exercício/métodos , Contração Isométrica , Instabilidade Articular/fisiopatologia , Instabilidade Articular/terapia , Traumatismos do Joelho/fisiopatologia , Músculo Esquelético/fisiopatologia , Adulto , Ligamento Cruzado Anterior/fisiopatologia , Biorretroalimentação Psicológica , Doença Crônica , Progressão da Doença , Eletromiografia , Marcha , Humanos , Instabilidade Articular/diagnóstico , Instabilidade Articular/etiologia , Masculino , Resultado do Tratamento
16.
J Electromyogr Kinesiol ; 7(2): 123-30, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20719697

RESUMO

The present study was aimed at assessing muscle inhibition (MI) of the quadriceps muscles of healthy subjects as a function of knee angle. The extent of muscle activation and of twitch potentiation following maximal contractions at different knee angles were investigated. Six males and four females (mean age 29.5 +/- 6.2 yr) performed three maximal isometric knee extensions on a KinCom dynamometer with the right and left legs at 15, 30, 45, 60 and 90 degrees from full extension. MI was assessed using the interpolated twitch technique. This technique requires surface stimulation of the femoral nerve during the maximal contractions. MI was estimated by the amount of extra torque evoked by the superimposed twitch. Electromyographical (EMG) activity of the vastus lateralis muscle was measured in order to estimate muscle activation. Twitch potentiation was assessed at 5, 20, 60 and 120 s after the maximal contractions by applying a single electrical twitch to the relaxed muscle. Results revealed a strong dependency of MI on the knee angle tested; MI increased with increasing muscle lengths and was almost three times higher at 60 degrees than at 15 degrees of full extension. Muscle activation measured as the root mean square (RMS) values of the vastus lateralis EMG was the same for four out of the five muscle lengths measured; at a knee angle of 90 degrees , the RMS values were significantly higher. Twitch potentiation was observed at all knee angles following maximal contractions. Potentiation was highest immediately after contraction (i.e. 5 s after), and the amount of potentiation did not depend on the knee angle. Muscle activation and twitch potentiation only accounted for a small percentage of the differences in MI as a function of knee angle. It is suggested that increased patellofemoral pressure and increased ligament strain, which are highest between 45 and 60 degrees of full extension, might be responsible for the high MI measured at these knee angles. It is further hypothesized that the differences in MI as a function of muscle length are also associated with the shortening of the contractile elements during contractions, and the concomitant loss in force potential; a phenomenon which is probably more pronounced at short compared to long muscle lengths.

17.
J Electromyogr Kinesiol ; 13(2): 159-67, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12586521

RESUMO

The aim of this study was to examine superficial quadriceps femoris (QF) EMG and torque at perceived voluntary contraction efforts. Thirty subjects (15 males, 15 females) performed 9, 5 s, sub-maximal contractions at prescribed levels of perceived voluntary effort at points 1-9 on an 11-point scale (0-10), in a random order. Surface electromyograms (EMG) of the vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) muscles, as well as QF peak torque (PT), average torque (AT), and torque coefficient of variation (C.V.), were sampled. The raw EMG signals were full-wave rectified and integrated over the middle three s of each contraction. The sampled EMG signals, and PT and AT at each perceived exertion level were normalized to the average of three maximal voluntary contractions. The normalized EMG and torque values at each perceived exertion level were then compared to equivalent percent values (i.e., 10% at a perceived level of 1). The results demonstrated that at all perceived exertion levels, with the exception of the RF at a level of 2 which was equivalent to 20%, and the VL and RF muscles at a level 1 in which activation was greater than 10%, activation was significantly less than the equivalent percent value at each point on the scale. VM EMG was found to be less than the VL and RF from contraction levels 3-9. PT was shown to be less than the equivalent percent values at contraction levels 6-9. The AT was found to be lower than the expected percent value at perceived effort levels 2-9. Torque C.V. was not found to be different across the range of perceived effort. The major findings of this study suggested that humans over-estimate voluntary QF muscle torque when guided by perceptual sensations. It is also suggested that the produced EMG signals revealed a reliance on the VL muscle for knee extensor torque generation at sub-maximal levels.


Assuntos
Contração Isométrica/fisiologia , Articulação do Joelho/fisiologia , Músculo Esquelético/fisiologia , Torque , Adulto , Análise de Variância , Fenômenos Biomecânicos , Intervalos de Confiança , Interpretação Estatística de Dados , Eletromiografia , Feminino , Humanos , Masculino , Valores de Referência , Análise e Desempenho de Tarefas , Volição/fisiologia
18.
Exp Toxicol Pathol ; 53(5): 365-72, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11817106

RESUMO

Fluoro-jade, a novel stain for detection of neuropathic lesions by fluorescence microscopy, was validated on the models of toxic neuropathy induced with 3-acetylpyridine (3-AP) or with acrylamide (ACR). Groups of male and female albino rats of Wistar strain were either exposed to a single administration of 80 mg/kg i.p. 3-AP followed 5 hours later by 300 mg/kg of nicotinamide i.p. and examined at days 3 and 15, or to 15 daily doses of 30 mg/kg p.o. ACR and examined at day 15. Following in-life behavioral observations and measurements, the rats were fixed by perfusion with formalin. Additional animals treated with same dose of 3-AP and nicotinamide were submitted to purposeful autolysis for 4 or 16 hours before immersion fixation with formalin on test day 3. In-life observations showed in 3-AP-treated animals signs of severe general toxicity, sensorimotor dysfunction and decreased motor activity starting shortly after the treatment and persisting throughout the observation period. ACR-treated rats started to develop abnormal gait on test day 8 and by day 15 developed reduced grip strength, increased landing footsplay and decreased motor activity. Fluoro-jade, applied to paraffin sections of the nervous system, detected selectively and sensitively the necrotic neurons in the brain, especially those in the inferior olivary nucleus of animals treated with 3-AP, at test day 3, as well as the necrotic Purkinje cells in the cerebellum of ACR-treated animals at test day 15. Chromatolytic neurons in the dorsal root ganglia of ACR-treated animals did not stain positively, indicating that this kind of reversible neuronal remodeling is not detectable using fluoro-jade. Necrotic neurons were still stained by fluoro-jade after 4 hour autolysis, but following 16 hour autolysis the results became false negative. There was no false positive fluorescence in fresh or autolytic tissues, except that emitted by red blood cells in unperfused specimens. The study confirmed the validity of fluoro-jade as a stain suitable for detecting necrotic neurons in toxicological safety studies.


Assuntos
Corantes Fluorescentes , Neurônios/patologia , Núcleo Olivar/patologia , Células de Purkinje/patologia , Animais , Feminino , Fluoresceínas , Microscopia de Fluorescência , Atividade Motora/efeitos dos fármacos , Necrose , Neurônios/efeitos dos fármacos , Núcleo Olivar/efeitos dos fármacos , Compostos Orgânicos , Células de Purkinje/efeitos dos fármacos , Ratos , Ratos Wistar
19.
J Sports Med Phys Fitness ; 32(4): 400-11, 1992 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1293424

RESUMO

To study the effect of long-term, self-monitored exercise on physical fitness and serum lipid levels of middle-aged, nonsmoking females, a controlled study was conducted in 33 sedentary Swiss women. Seventeen women were randomly allocated to jog 2h/wk for 4 months on an individually prescribed and heart rate controlled base, whereas 16 women served as controls. Although leisure-time physical activity increased significantly in exercisers compared to controls, the average running distance of 10.9 km/wk was somewhat less than expected. The "net decrease" (4-month change in exercisers minus 4-month change in controls) in the sum of four skin-folds was -4.85 mm (p < 0.05). Four-month changes in serum lipids were generally small and nonsignificant. For example, the net decrease in total triglycerides was -0.2 mmol/l (p = 0.13). Correlational analyses revealed significant associations between changes in the waist-hip ratio and changes in total cholesterol (total-C) or the HDL/total-C ratio (r = 0.44, p < 0.01 and r = -0.29, p < 0.05, respectively). An increase in endurance capacity was associated with an increase in the HDL2-subfraction and in the ratio of HDL/total-C (r = 0.46, p < 0.05 and r = 0.52, p < 0.01). Multivariate linear regression analyses confirmed a change in endurance capacity as the statistically strongest positive predictor of changes in HDL, HDL2 and the HDL/total-C ratio. However, women who used oral contraceptives did not show any favourable lipid changes despite a considerable improvement in endurance capacity. The present training study in healthy, habitually sedentary middle-aged women was not able to show the same beneficial changes in serum HDL concentration as seen in male counterparts, when analyzed according to the principle of intention-to-treat. Exploratory analyses revealed that a too low jogging activity as well as a confounding effect of oral contraceptive use may partially account for the lack of significant changes in serum lipid levels after training.


Assuntos
Exercício Físico , Lipídeos/sangue , Aptidão Física , Adulto , Antropometria , Colesterol/sangue , Doença das Coronárias/prevenção & controle , Feminino , Humanos , Estilo de Vida , Lipoproteínas HDL/sangue , Pessoa de Meia-Idade , Fatores de Risco , Fatores de Tempo
20.
Soz Praventivmed ; 38 Suppl 2: S122-4, 1993.
Artigo em Alemão | MEDLINE | ID: mdl-8279185

RESUMO

In a study sample of 75 sedentary, non-smoking male bank employees (mean age 41.2 +/- 7.8 years) the relationship between lifestyle characteristics and serum lipid concentrations were examined. According to the mortality statistics of the canton of Zurich, this population is at increased risk for coronary heart disease. Statistical analyses confirmed the predictive character of physical activity for serum lipid levels. A low level of physical activity was associated with significantly higher concentrations of apolipoprotein B and LDL-C (Pearson coefficient of correlation r = -0.38, p < 0.001 and r = -0.35, p < 0.01, respectively). Accumulation of upper body fat (estimated by the waist to hip ratio) revealed to be a better predictor of lipid levels than body mass index and showed highly significant positive correlations with atherogenic lipid fractions. The most pronounced differences were seen for triglyceride levels, where the subgroup of subjects in the lowest tertile of waist-hip ratio showed about 40% lower triglyceride values compared to the highest waist-hip ratio tertile. In a study population of self-selected, non-smoking men, high levels of LDL-C and apolipoprotein B could partially be explained by unfavourable life style characteristics, particularly physical inactivity. The waist-hip ratio, characterizing abdominal fat accumulation, proved to be a good indicator of an atherogenic lipid profile. Measuring waist-hip ratio in medical routine examinations should thus be considered.


Assuntos
Estilo de Vida , Lipídeos/sangue , Ocupações , Adulto , Índice de Massa Corporal , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Estudos de Coortes , Doença das Coronárias/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Aptidão Física , Fatores de Risco
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