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The soil carbon (C) dynamics is strongly influenced by climate and land-use patterns in the Himalayas. Therefore, soils under five prominent land use [e.g., maize (Zea mays), horticulture, natural forest, grassland, and wasteland] were sampled down up to 30 cm depth under two climatic conditions viz., temperate and subtropical to assess the impacts of climate and landuse on soil C dynamics. Results demonstrated that irrespective of land use, temperate soil contains 30.66% higher C than subtropical soils. Temperate soils under natural forests had the higher total organic carbon (TOC, 21.90 g kg-1), Walkley-Black carbon (WBC, 16.42 g kg-1), contents, and stocks (TOC, 66.92 Mg ha-1 and WBC, 50.24 Mg ha-1), and total soil organic matter (TSOM, 3.78%) concentration as compared to other land uses like maize, horticulture, grassland, and wasteland. Under both climatic conditions, maize land use had the lowest TOC 9.63, 6.55 g kg-1 and WBC 7.22, 4.91 g kg-1 at 0-15 and 15-30 cm soil depth, respectively. Horticulture land use had 62.58 and 62.61% higher TOC and WBC over maize-based land use under subtropical and temperate climatic conditions at 0-30 cm soil depth, respectively. However, soils of maize land use under temperate conditions had â¼2 times more TOC than in subtropical conditions. The study inferred that the C-losses is more in the subtropical soil than in temperate soils. Hence, the subtropical region needs more rigorous adoption of C conservation farming practices than the temperate climatic setting. Although, the adoption of C storing and conserving practices is crucial under both climatic settings to arrest land degradation. Horticultural land uses along with conservation effective soil management practices may be encouraged to restore more soil C and to improve the livelihood security of the hill populace in the North Western Himalayas.
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Carbono , Solo , Conservação dos Recursos Naturais , Agricultura/métodos , Florestas , Zea maysRESUMO
Male reproductive functions are governed by hypothalamic pituitary testicular axis. If any component of this axis malfunctions, then hypogonadism will develop which is characterized by ill-defined secondary sexual features and low serum testosterone. The common patterns seen are primary and secondary testicular failure in the young; and late onset hypogonadism in the elderly. All such cases can be virilized and managed by androgen supplementation. Spermatogenesis can be induced by use of appropriate gonadotropins in selected cases. The aim of the study was to find out the pattern, management and outcome of male hypogonadism. MATERIAL: It was a prospective questionnaire based observational study, carried out on infertile hypogonadic males, attending medicine outdoor at medical college hospital from January 2015 to December 2020. There were 50 males with hypogonadic features, cases of late onset of hypogonadism were excluded. Sexual maturity rating, semen analysis, serum testosterone and FSH level were estimated in all patients at baseline and at 6 months duration of treatment. Testicular biopsy, Karyotyping and MRI brain were performed in selected cases. Azoospermic patients having hypogonadotropic hypogonadism were treated with long-acting testosterones and gonadotropins. OBSERVATION: The study subjects were infertile azoospermic males. On the basis of serum FSH and testosterone levels, they were classified into two groups. Group A (n=42) cases were hypergonadotropic hypogonadism or primary testicular failure; of these 32 were Klinefelter syndrome (XXY), 7 chronic orchitis and 3 empty scrotal syndrome including one case of anorchia. These patients also developed other systemic illnesses in addition to hypogonadism. Group B (n=8) hypogonadotropic hypogonadism or secondary testicular failure; of these 2 were Kallman syndrome and the rest were idiopathic. After testosterone replacement all patients were virilized and there was marked improvement in libido and androgenization. CONCLUSION: The study brings out that primary testicular failure is more common than secondary testicular failure. Both pattern of hypogonadism should receive lifelong androgen replacement therapy; otherwise, they will be a basket of multiple systemic disorders. Presently testosterone undecanoate once in every three months is the agent of choice.
Assuntos
Azoospermia , Hipogonadismo , Idoso , Feminino , Hormônio Foliculoestimulante , Disgenesia Gonadal 46 XY , Gonadotropinas , Humanos , Hipogonadismo/tratamento farmacológico , Índia/epidemiologia , Masculino , Estudos Prospectivos , Testículo/anormalidades , Testosterona/uso terapêutico , Resultado do TratamentoRESUMO
Widespread of heavy metals contamination has led to several environmental problems. Some biological methods to remove heavy metals from contaminated wastewater are being widely explored. In the present study, the efficiency of a white-rot fungus, Phlebia brevispora to remove different metals (Pb, Cd and Ni) has been evaluated. Atomic absorption spectroscopy of treated and untreated metal containing water revealed that all the metals were efficiently removed by the fungus. Among all the used metals, cadmium was the most toxic metal for fungal growth. Phlebia brevispora removed maximum Pb (97·5%) from 100 mmol l-1 Pb solution, which was closely followed by Cd (91·6%) and Ni (72·7%). Scanning electron microscopic images revealed that the presence of metal altered the morphology and fine texture of fungal hyphae. However, the attachment of metal on mycelia surface was not observed during energy-dispersive X-ray analysis, which points towards the intracellular compartmentation of metals in vacuoles. Thus, the study demonstrated an application of P. brevispora for efficient removal of Pb, Cd and Ni from the metal contaminated water, which can further be applied for bioremediation of heavy metals present in the industrial effluent.
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Cádmio/metabolismo , Chumbo/metabolismo , Níquel/metabolismo , Polyporales/metabolismo , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodos , Biodegradação Ambiental , Metais Pesados/metabolismo , Águas Residuárias/análiseRESUMO
Background Multidrug resistant in clinical bacterial isolates has increasingly been reported through out the world and is associated with high morbidity, mortality and increased health care costs. It is important to determine the status of multidrug resistance pattern to understand the current resistance trend so that appropriate antibiotics can be used in practice. Objective To determine the antibiotic resistant profile and prevalence of extended spectrum ß-lactamase producing multidrug resistant strains in pediatric patients of Kanti Children's Hospital, Kathmandu, Nepal. Method Urine sample was cultured by standard microbiological techniques and bacterial isolates were identified using different biochemical tests. Antibiotic susceptibility testing was performed by Kirby Bauer disc diffusion method and extended spectrum ß-lactamase detection was carried out using combined disc method as recommended by Clinical Laboratory Standard Institute guidelines. Result All together 65 different bacteria were isolated and subsequently identified. E. coli was the most common isolate with 46 (71%) isolates 63% of these isolates were multidrug resistant. Gram negative isolates were most resistant to nalidixic acid (81.97%) followed by ampicillin (69.35%) and co-trimoxazole (69.35%). The extended spectrum ß-lactamase producing isolates were 43% among total isolates. Conclusion Higher rate of Extended Spectrum ß-lactamase production among multidrug resistant isolates suggested routine extended spectrum ß-lactamase testing in clinical isolates.
Assuntos
Bactérias/isolamento & purificação , Resistência a Múltiplos Medicamentos , Urina/microbiologia , beta-Lactamases/análise , Antibacterianos/farmacologia , Proteínas de Bactérias/análise , Criança , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Hospitais Pediátricos , Humanos , Testes de Sensibilidade Microbiana , NepalRESUMO
Genetic variability studies for needle and wood traits were carried out for the different half sib progenies of Chir pine, raised in 1985 at the main campus of University. There existed a significant variation for these traits among the different half sib progenies, viz., needle length (18.1-24.6 cm), needle thickness (0.53-0.71 mm), number of stomata per mm of a row (7.3-12.0), specific gravity of wood (0.36-0.46), tracheid length (1.51-1.85) and moisture content of wood (47.76-58.81). This variability was found under genetic control, as all these progenies are growing under same environment, and are of same age. Traits having high heritability and genetic gain like, needle thickness, wood specific gravity, tracheid length and others, indicate high genetic control. This variability can be exploited in tree improvement programs through selection and breeding approaches for development of advanced generations. Correlation studies for different traits at genotypic and phenotypic levels provided the basic knowledge of association to chalk out efficient breeding strategy for higher productivity through indirect selection.
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BACKGROUND: The use of sevoflurane without muscle relaxant for tracheal intubation has been widely investigated in children. Non-depolarizing neuromuscular blockers have long duration of action and do not provide rapid return of spontaneous ventilation. Use of suc-cinylcholine has been found to be associated with various side-effects especially in children. Therefore, we aim to evaluate the effect of propofol 1.5 mg/kg without muscle relaxant, on intubating conditions in children 2-8 yrs of age and we compare them with those achieved with rocuronium 0.6 mg/kg, at moderate sevoflurane concentration. METHODS: Fifty children between 2-8 yrs, ASA I or II scheduled for elective surgery were randomly allocated to either Group P (propofol) or group R (rocuronium). After premedication with oral midazolam 0.5 mg/kg 30 min before surgery, anaesthesia was induced with 8% sevoflurane in oxygen. Intravenous fentanyl 1 µg/kg was administered after securing intravenous access and dial concentration of sevoflurane was reduced to 4%. At one minute with regards to time T0, the patients received the drug which was either intravenous rocuronium 0.6 mg/kg or an equal volume of 0.9% saline (D) and at three minutes (two minutes after D1), second drug (D2) was given, which was either propofol 1.5 mg/kg or an equal volume of 0.9% saline according to the group allocated. At four minutes, laryngoscopy was done and intubation performed with appropriate sized uncuffed endotracheal tube. Incidence of acceptable and excellent intubating conditions, time to intubation and hemodynamic parameters were recorded. RESULTS: Incidence of acceptable or excellent intubating conditions was similar in both groups (p = 1.00). The difference in time to intubation was statistically not significant (25.03 ± 6.05s in Group P and 24.38 ?5.58s in Group R, p = 0.694), at similar end-tidal concentration of sevoflurane (3.2 ± 0.20% in Group P and 3.1 ± 0.20% in Group R, p = 0.12). CONCLUSION: Propofol (1.5 mg/kg) and rocuronium (0.6 mg/kg) produced similar intubating conditions in children induced with sevoflurane.
Assuntos
Androstanóis/farmacologia , Intubação Intratraqueal/estatística & dados numéricos , Éteres Metílicos/farmacologia , Propofol/farmacologia , Anestésicos Inalatórios/farmacologia , Anestésicos Intravenosos/farmacologia , Criança , Pré-Escolar , Método Duplo-Cego , Feminino , Humanos , Masculino , Fármacos Neuromusculares não Despolarizantes/farmacologia , Estudos Prospectivos , Rocurônio , SevofluranoRESUMO
Chemicals are often dosed to control the production and accumulation of hydrogen sulfide in sewers. The biological and/or chemical actions of these chemicals have profound impacts on the composition of wastewater entering a WWTP, thereby affecting its performance. In this paper, an integrated modelling methodology for simultaneously investigating the effects of dosing of chemicals in sewer network and N and P removal at the downstream WWTP is reported. The sewer system is modelled using a sewer model (SeweX), and the WWTP is modelled using ASM2d model with some modifications. The importance of integrated modelling in sewer management is also demonstrated.
Assuntos
Drenagem Sanitária , Modelos Teóricos , Purificação da Água , Nitrogênio/análise , Fósforo/análise , Esgotos/análise , Sulfetos/análiseRESUMO
A benchmark simulation model, which includes a wastewater treatment plant (WWTP)-wide model and a rising main sewer model, is proposed for testing mitigation strategies to reduce the system's greenhouse gas (GHG) emissions. The sewer model was run to predict methane emissions, and its output was used as the WWTP model input. An activated sludge model for GHG (ASMG) was used to describe nitrous oxide (N(2)O) generation and release in activated sludge process. N(2)O production through both heterotrophic and autotrophic pathways was included. Other GHG emissions were estimated using empirical relationships. Different scenarios were evaluated comparing GHG emissions, effluent quality and energy consumption. Aeration control played a clear role in N(2)O emissions, through concentrations and distributions of dissolved oxygen (DO) along the length of the bioreactor. The average value of N(2)O emission under dynamic influent cannot be simulated by a steady-state model subjected to a similar influent quality, stressing the importance of dynamic simulation and control. As the GHG models have yet to be validated, these results carry a degree of uncertainty; however, they fulfilled the objective of this study, i.e. to demonstrate the potential of a dynamic system-wide modelling and benchmarking approach for balancing water quality, operational costs and GHG emissions.
Assuntos
Pegada de Carbono , Metano , Modelos Teóricos , Óxido Nitroso , Gerenciamento de Resíduos/normas , Benchmarking , Análise da Demanda Biológica de Oxigênio , OxigênioRESUMO
Pseudo Class III malocclusion is characterized by an anterior crossbite with functional forward mandibular displacement. Various appliances have been devised for early treatment of a pseudo Class III. The aim of this article is to highlight the method of construction and use a simple removable appliance termed as "Modified Hawleys appliance with inverted labial bow" to treat psuedo class III malocclusion in the mixed dentition period. It also emphasizes the importance of differentiating between true Class III and pseudo Class III. This appliance in this type of malocclusion enabled the correction of a dental malocclusion in a few months and therapeutic stability of a mesially positioned mandible encouraging favorable skeletal growth.
Assuntos
Aparelhos Ativadores , Má Oclusão Classe III de Angle/terapia , Desenho de Aparelho Ortodôntico , Ortodontia Interceptora/instrumentação , Criança , Oclusão Dentária Central , Dentição Mista , Seguimentos , Humanos , Masculino , Aparelhos Ortodônticos Removíveis , Planejamento de Assistência ao PacienteRESUMO
BACKGROUND: Evidence is accumulating that patients with polyneuropathy may present with normal clinical deep tendon reflexes (C-DTR). There are few studies that assessed the diagnostic utility of electromyographically recorded DTR (Er-DTR) in patients with polyneuropathy. OBJECTIVES: The objectives of this study were twofold: (i) to evaluate the prevalence of preserved C-DTR in polyneuropathy; (ii) diagnostic value of Er-DTR latency measurement in patients with polyneuropathy. METHODS: We prospectively studied 38 controls and 185 patients with polyneuropathy. All subjects had evaluation of C-DTR, Er-DTR obtained from right biceps brachii (BR), right patellar (PR) and bilateral ankle reflexes (AR). RESULTS: Of these 185 patients, 118 (63.8%) had chronic axonal neuropathy (CAN), 49 (26.5%) demyelinating polyradiculoneuropathy (DPN) and 18 (9.7%) small fiber neuropathy (SFN). The C-DTR were normal in 65 patients whereas 39 of these 65 (60%) patients had abnormalities of Er-DTR at one or more sites. Er-DTR latencies in patients with polyneuropathies were prolonged at all sites compared with controls (P < 0.01). Among patients with various types of polyneuropathies the Er-DTR, mean latencies at all the sites and latency indicative of demyelination (>150% of the normal mean) were higher in patients with DPN than that of CAN or SFN (P < 0.01). CONCLUSIONS: We conclude that C-DTR are preserved in 35.1% of the patients with polyneuropathies and Er-DTR should be performed in such patients in order to provide electrophysiological evidence of a polyneuropathy. Er-DTR are useful in distinguishing axonal from demyelinating disorders of peripheral nerve, and detection of subclinical involvement of large fibers in SFN.
Assuntos
Polineuropatias/diagnóstico , Polineuropatias/epidemiologia , Reflexo/fisiologia , Braço/fisiopatologia , Eletromiografia , Feminino , Reflexo H/fisiologia , Humanos , Perna (Membro)/fisiopatologia , Masculino , Pessoa de Meia-Idade , Condução Nervosa , Polineuropatias/fisiopatologia , Prevalência , Tendões/fisiopatologiaRESUMO
Boron (B) availability to crop plants depends on soil properties as well as management practices like liming, fertilization and use of organic manures. To assess the effect of farmyard manure (FYM) application on availability of added B, adsorption-desorption of B was investigated in five different soils receiving varying doses of FYM (0, 5 and 10 g FYM kg(-1) soil). Two surfaces Freundlich model was found best to account for B adsorption-desorption data of all soils. Application of FYM increased B adsorption capacities pertaining to low (K1) and high (K2) concentration ranges in all soils, except Soil C (Alfisol) having a pH of 9.8, in which the higher rate of FYM decreased the value of K2. Application of FYM did not change B desorption capacities of soils corresponding to low B concentration range (K(1)(1)) significantly, however, it increased B desorption capacity pertaining to high B concentration (K(1)(2)) in all soils, except Soils C (Alfisol) and E (Entisol) having pH of 9.8 and 5.1, respectively. Application of FYM increased the desorption slope factor applicable to low concentration range (1/n(1)(1)) in Soil A (Inceptisol), but decreased it in Soil E (Entisol). The 1/n(1)(2) (desorption slope factor applicable to high concentration range) decreased with FYM application in all soils except Soil E (Entisol), where it was increased. Boron desorption index (slope(ads)/slope(des)) decreased with FYM application in low B concentration range, but increased in high concentration range for all soils except soil E (Entisol, pH 5.1), in which a reverse trend was observed. Application of FYM increased the retention of added B in soils and may help reducing the leaching losses.
Assuntos
Boro/química , Monitoramento Ambiental , Esterco , Poluentes do Solo/metabolismo , Adsorção , Agricultura , Concentração de Íons de Hidrogênio , Poluentes do Solo/análise , Propriedades de Superfície , TermodinâmicaRESUMO
An integrated anaerobic-aerobic treatment system of sulphate-laden wastewater was proposed here to achieve low sludge production, low energy consumption and effective sulphide control. Before integrating the whole system, the feasibility of autotrophic denitrification utilising dissolved sulphide produced during anaerobic treatment of sulphate rich wastewater was studied here. An upflow anaerobic sludge blanket reactor was operated to treat sulphate-rich synthetic wastewater (TOC=100 mg/L and sulphate=500 mg/L) and its effluent with dissolved sulphide and external nitrate solution were fed into an anoxic biofilter. The anaerobic reactor was able to remove 77-85% of TOC at HRT of 3 h and produce 70-90 mg S/L sulphide in dissolved form for the subsequent denitrification. The performance of anoxic reactor was stable, and the anoxic reactor could remove 30 mg N/L nitrate at HRT of 2 h through autotrophic denitrification. Furthermore, sulphur balance for the anoxic filter showed that more than 90% of the removed sulphide was actually oxidised into sulphate, thereby there was no accumulation of sulphur particles in the filter bed. The net sludge productions were approximately 0.15 to 0.18 g VSS/g COD in the anaerobic reactor and 0.22 to 0.31 g VSS/g NO3- -N in the anoxic reactor. The findings in this study will be helpful in developing the integrated treatment system to achieve low-cost excess sludge minimisation.
Assuntos
Nitrogênio/metabolismo , Esgotos/química , Sulfatos/análise , Sulfatos/metabolismo , Eliminação de Resíduos Líquidos/economia , Eliminação de Resíduos Líquidos/métodos , Filtração , Hong Kong , Nitratos/química , Oxirredução , Oxigênio/química , SolubilidadeRESUMO
OBJECTIVE: To examine the autonomic nervous system functions in patients with Huntington disease. BACKGROUND: Although patients with Huntington disease frequently experience vegetative symptoms, it is not clear if there is dysfunction of the autonomic nervous system. METHODS: Sympathetic skin response (SSR) latency and amplitude from both palms and soles and R-R (heart rate) interval variation (RRIV) at rest and during the Valsalva maneuver were examined in 22 patients and 21 age-matched controls. Unified Huntington's Disease Rating Scale scores were determined in all the patients. RESULTS: Our data are reported as means +/- SEMs. The SSR latencies in patients (mean palm latency, 1835.8+/-110.7 milliseconds; mean sole latency, 2625.3+/-226.9 milliseconds) were prolonged compared with controls (mean palm latency, 1359.5+/-28 milliseconds [P<.01]); mean sole latency, 2038.1+/-44.9 milliseconds [P<.01]) and amplitudes in patients (mean amplitude, 1063.1+/-237.7 microV) were smaller compared with controls (mean amplitude, 1846.3+/-251.2 microV [P<.05]). The RRIV in patients both at rest (mean RRIV in patients, 3.7%+/-0.4% vs. controls, 9.7%+/-0.6% [P<.01]) and during the Valsalva maneuver (mean RRIV in patients, 6.3%+/-1.6% vs. controls, 14.5%+/-1.2% [P<.01]) was lower compared with controls. Furthermore, the prolonged SSR latencies, smaller amplitudes, and lower RRIV in patients compared with controls closely correlated with the various components of the Unified Huntington's Disease Rating Scale scores (total behavior score and SSR latency, R = 0.6 [P<.01]; total behavior score and SSR amplitude, R = -0.5 [P<.05]; total behavior score and RRIV, R = -0.4 [P<.05]; verbal fluency and SSR latency, R = -0.5 [P<.05]; verbal fluency and SSR amplitude, R = 0.5 [P<.05], verbal fluency and RRIV, R = 0.5 [P<.05]; total functional capacity and SSR latency, R = -0.6 [P<.01]; total functional capacity and SSR amplitude, R = 0.5 [P<.05]). CONCLUSION: These results suggest that there is autonomic nervous system dysfunction in patients with Huntington disease.
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Sistema Nervoso Autônomo/fisiopatologia , Resposta Galvânica da Pele , Frequência Cardíaca , Doença de Huntington/fisiopatologia , Adulto , Idoso , Feminino , Humanos , Doença de Huntington/diagnóstico , Masculino , Pessoa de Meia-Idade , Condução Nervosa , Nervo Fibular/fisiologia , Tempo de Reação , Nervo Sural/fisiologia , Manobra de ValsalvaRESUMO
We investigated the effect of cyclosporine (CsA) on force generation in 15 boys with Duchenne muscular dystrophy (DMD) by obtaining monthly measures of tetanic force and maximum voluntary contraction (MVC) of both anterior tibial muscles. During 4 months of a natural history phase, both tetanic force and MVC declined significantly. During 8 weeks of CsA treatment (5 mg/kg/day), significantly increased tetanic force (25.8 +/- 6.6%) and MVC (13.6 +/- 4.0%) occurred within 2 weeks. The maximum mean increase during treatment was 35.2 +/- 5.9% (tetanic force) and 19.0 +/- 4.6% (MVC). Side effects from CsA, gastrointestinal and flu-like symptoms, were transient and self-limiting. Thus, as previously reported with prednisone, CsA increases muscular force generation in the anterior tibial muscles of DMD patients.
Assuntos
Ciclosporina/farmacologia , Músculos/efeitos dos fármacos , Distrofias Musculares/fisiopatologia , Potenciais de Ação/efeitos dos fármacos , Criança , Pré-Escolar , Ciclosporina/efeitos adversos , Humanos , Rim/efeitos dos fármacos , Masculino , Contração Muscular/efeitos dos fármacos , Músculos/fisiopatologiaRESUMO
We used a 4-minute sustained maximum voluntary contraction to investigate fatigability of the anterior tibial muscle in eight healthy boys and 11 boys with Duchenne muscular dystrophy (DMD) (ages 5 to 10 years). Before exercise, the force generation of dystrophic muscle and the compound muscle action potential amplitude were lower and half-relaxation time of the tetanus was longer in patients than in controls. During exercise, the decline in tetanic force and potentiation in twitch tension were similar in both groups. However, during exercise, there was less decline in maximum voluntary contraction and less added force in DMD patients, suggesting that there was less central fatigue in patients than in controls. Thus, patients with DMD and controls have similar intramuscular fatigability and excitation-contraction coupling, and central activation in patients is functioning as well as or better than in healthy controls.
Assuntos
Fadiga Muscular , Músculo Esquelético/fisiopatologia , Distrofias Musculares/fisiopatologia , Adolescente , Análise de Variância , Criança , Estimulação Elétrica , Teste de Esforço , Humanos , Contração Isométrica , Masculino , Contração Muscular , Relaxamento Muscular , Músculo Esquelético/fisiologia , Valores de ReferênciaRESUMO
We report the clinical features of five patients with lumbosacral radiculoplexopathy (LSRP) and one patient with a femoral neuropathy, all of whom had serologic evidence of a recent Epstein-Barr virus (EBV) infection. After a thorough investigation, no other etiology was apparent. Pain was a prominent feature in all cases, and the prognosis was generally good, with recovery in weeks to months. We conclude that LSRP may occur as a postinfectious process following recent EBV infection.
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Herpesvirus Humano 4 , Mononucleose Infecciosa/complicações , Plexo Lombossacral , Raízes Nervosas Espinhais , Adulto , Idoso , Reações Antígeno-Anticorpo , Antígenos Virais/análise , Eletrofisiologia , Feminino , Nervo Femoral , Herpesvirus Humano 4/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Doenças do Sistema Nervoso Periférico/etiologia , Doenças do Sistema Nervoso Periférico/imunologia , Doenças do Sistema Nervoso Periférico/fisiopatologiaRESUMO
We present the 1st report of chronic segmental spinal muscular atrophy confined to the upper extremities in identical male twins. This occurrence in identical twins, together with reports of siblings and parent-child pairs of a disorder phenotypically similar to the more common sporadic form in the literature, suggests a genetic etiology in some cases.
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Doenças em Gêmeos/genética , Atrofia Muscular Espinal/genética , Idoso , Braço , Doença Crônica , Eletromiografia , Humanos , Masculino , Músculos/fisiopatologia , Atrofia Muscular Espinal/fisiopatologia , Condução NervosaRESUMO
To investigate anterior tibial muscle fatigability and metabolism in postpoliomyelitis syndrome patients and controls, we performed measurements of force and relaxation time, as well as 31P magnetic resonance spectroscopy, during intermittent, low-intensity, isometric, voluntary exercise. Both maximum voluntary contraction and tetanic force declined significantly more during exercise and subsequently recovered less in patients compared with controls, indicating greater fatigue in patients. However, intracellular pH and phosphocreatine were not different in the two groups at rest or during exercise or recovery, suggesting that the greater fatigue of the patients was not due to an excessive change of metabolites. Moreover, the pre-exercise half-relaxation time of the tetanus was significantly prolonged in patients compared with controls, and the decline in tetanic force during exercise was linearly related to the half-relaxation time of tetanus, suggesting impaired calcium kinetics. Taken together, the findings of increased fatigability, delayed recovery, and prolonged half-relaxation time, without differences in metabolites, suggest that the fatigue in postpoliomyelitis syndrome may be due to impaired activation beyond the muscle membrane.
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Doenças Musculares/complicações , Síndrome Pós-Poliomielite/complicações , Potenciais de Ação , Idoso , Feminino , Humanos , Contração Isométrica , Masculino , Pessoa de Meia-Idade , Contração Muscular , Músculos/metabolismo , Músculos/fisiopatologia , Doenças Musculares/fisiopatologia , Fosfocreatina/metabolismo , Esforço FísicoRESUMO
We studied whether muscle fatigue, metabolism, or activation are abnormal in the chronic fatigue syndrome (CFS). Subjects performed both an intermittent submaximal and a sustained maximal voluntary isometric exercise protocol of the tibialis anterior muscle. The extent of fatigue, metabolic response, and changes in both M-wave amplitude and twitch tension during exercise were similar in patients and controls. The response to systemic exercise was also normal in the patients. However, voluntary activation of the tibialis was significantly lower in the patients during maximal sustained exercise. The results indicate that patients with CFS have (1) normal fatigability and metabolism at both the intracellular and systemic levels, (2) normal muscle membrane function and excitation-contraction coupling, and (3) an inability to fully activate skeletal muscle during intense, sustained exercise. This failure of activation was well in excess of that found in controls, suggesting an important central component of muscle fatigue in CFS.
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Síndrome de Fadiga Crônica/etiologia , Contração Muscular/fisiologia , Adulto , Eletromiografia , Exercício Físico/fisiologia , Síndrome de Fadiga Crônica/fisiopatologia , Feminino , Humanos , Contração Isométrica/fisiologia , Lactatos/sangue , Masculino , Músculos/metabolismoRESUMO
We investigated the mechanisms of muscle fatigue in ALS. In the muscles of ALS patients and healthy control subjects, we examined (1) fatigue using measurements of muscle force, (2) energy metabolism using phosphorus-31 magnetic resonance spectroscopy, and (3) activation using neurophysiologic measures and MRI. During 25 minutes of intermittent isometric exercise of the tibialis anterior muscle, both maximum voluntary and tetanic force declined more in patients than in controls, indicating greater fatigability in ALS. There was a similar decline of voluntary and tetanic force, suggesting that much of the fatigue was not central. Evoked compound muscle action potential amplitudes were preserved during exercise in both groups, indicating no failure of neuromuscular transmission; this result suggests that the source of fatigue was not at the neuromuscular junction or within the muscle membrane. In spite of greater fatigability, changes during exercise in energy metabolites and proton signal intensity tended to be less in ALS patients compared with controls, suggesting impaired muscular activation. We conclude that the greater muscle fatigue in ALS patients results from activation impairment, due in part to alterations distal to the muscle membrane.