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1.
J Frailty Aging ; 12(3): 208-213, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37493381

RESUMO

BACKGROUND: In older people, frailty has been recognized as an important prognostic factor. However, only a few studies have focused on multidimensional frailty as a predictor of mortality and readmission among inpatients with pneumonia. OBJECTIVE: The present study aimed to assess the association between preadmission frailty and clinical outcomes after the hospitalization of older patients with pneumonia. DESIGN: Single-center, retrospective case-control study. SETTING: Acute phase hospital at Kobe, Japan. PARTICIPANTS: The present study included 654 consecutive older inpatients with pneumonia. MEASUREMENTS: Frailty status before admission was assessed using total Kihon Checklist (KCL) score, which has been used as a self-administered questionnaire to assess comprehensive frailty, including physical, social, and cognitive status. The primary outcome was a composited 6-month mortality and readmission after discharge. RESULTS: In total, 330 patients were analyzed (median age: 79 years, male: 70.4%, median total KCL score: 10 points), of which 68 were readmitted and 10 died within 6 months. After multivariate analysis, total KCL score was associated with a composited 6-month mortality and readmission (adjusted hazard ratio, 1.07; 95% confidence interval, 1.02-1.12; p = 0.006). The cutoff value for total KCL score determined by receiver operating characteristic curve analysis was 15 points (area under the curve = 0.610). The group with a total KCL score ≥ 15 points had significantly higher readmission or mortality rates than the groups with a total KCL score < 15 points (p < 0.001). CONCLUSIONS: Preadmission frailty status in older patients with pneumonia was an independent risk factor for readmission and survival after hospitalization.


Assuntos
Fragilidade , Pneumonia , Humanos , Masculino , Idoso , Fragilidade/diagnóstico , Idoso Fragilizado , Readmissão do Paciente , Estudos Retrospectivos , Estudos de Casos e Controles , Avaliação Geriátrica/métodos
2.
Eur J Neurol ; 27(11): 2117-2124, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32558010

RESUMO

BACKGROUND AND PURPOSE: The detection rate of diffusion-weighted (DWI) hyperintense lesions varies widely in patients with transient global amnesia (TGA). The aim was to examine the association of hyperintense lesions on DWI magnetic resonance imaging (MRI) with patient characteristics, precipitating factors, clinical presentation and MRI settings in patients with TGA. METHODS: In this multicenter retrospective observational study, using the standardized diagnosis entry system of electronic health records of four tertiary medical centers in the Kansai district of Japan, TGA patients (n = 261) who underwent brain MRI within 28 days of onset were examined. When the onset time was unavailable, the discovery time was used. RESULTS: Diffusion-weighted hyperintense lesions were observed in 79 patients (30%). There were no significant differences in age, sex, vascular risk factors, precipitating factors or clinical presentation between patients with and without DWI lesions. The detection rate increased linearly 24 h after onset and then reached a plateau of 60%-80% by 84 h. After 84 h, the detection rate decreased rapidly. In a multivariate logistic regression model, MRI examination 24-84 h after onset (odds ratio 7.00, 95% confidence interval 3.50-13.99) and a thin-slice (≤3 mm) DWI sequence (odds ratio 7.59, 95% confidence interval 3.05-18.88) were independent predictors of DWI lesions. CONCLUSIONS: This study suggests that DWI hyperintense lesions in TGA are not associated with patient characteristics and clinical presentation. Brain MRI examination 24-84 h after onset and thin-slice DWI sequences enhance the detection of DWI lesions in TGA patients.


Assuntos
Amnésia Global Transitória , Amnésia Global Transitória/diagnóstico por imagem , Hipocampo , Humanos , Japão/epidemiologia , Imageamento por Ressonância Magnética
4.
Int J Clin Pharmacol Ther ; 49(5): 339-43, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21543038

RESUMO

OBJECTIVE: It was reported that the drug-induced fever of teicoplanin tended to persist after cessation of treatment. It is considered that the long half-life of teicoplanin causes the phenomenon. However there was no detailed report regarding plasma concentration of teicoplanin during onset of drug induced-fever. Therefore we investigated the relation between persistence of drug-induced fever and plasma concentration of teicoplanin. CASE: A 38-year-old male patient on the Left Ventricular Assist System (LVAS) was treated with teicoplanin for methicillin-resistant Staphylococcus aureus (MRSA) and he experienced drug-induced fever. Plasma concentrations of teicoplanin were measured not only during the treatment with the drug but also after it was discontinued. As such, plasma concentration was measured even when the fever had subsided. RESULTS: On Day 9 of treatment, the dose was increased from 400 to 600 mg, but the patient had a fever of about 38 - 39 °C. When the treatment was discontinued, it took 9 days for the fever to subside to a temperature of about 37 °C. The half-life of elimination of teicoplanin in the elimination phase is about 108 h, which is long. The fever persisted until the plasma concentration decreased to below 10 µg/ml, which is the effective trough concentration, and subsided when the estimated blood concentration was 7.5 µg/ml. CONCLUSIONS: We suggest that there is the possibility that the drug-induced fever due to teicoplanin persisted until the plasma concentration had decreased adequately. Close monitoring of plasma concentration is necessary, particularly when teicoplanin clearance is decreased such as in patients with renal dysfunction.


Assuntos
Antibacterianos/efeitos adversos , Febre/induzido quimicamente , Teicoplanina/efeitos adversos , Acetaminofen/uso terapêutico , Antibacterianos/farmacocinética , Antipiréticos/uso terapêutico , Cardiomiopatia Dilatada/complicações , Cardiomiopatia Dilatada/terapia , Febre/tratamento farmacológico , Meia-Vida , Coração Auxiliar , Humanos , Contagem de Leucócitos , Masculino , Staphylococcus aureus Resistente à Meticilina , Pessoa de Meia-Idade , Contagem de Plaquetas , Infecções Estafilocócicas/complicações , Infecções Estafilocócicas/tratamento farmacológico , Teicoplanina/farmacocinética
5.
Neurology ; 59(7): 1102-4, 2002 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-12370475

RESUMO

The authors describe a patient with dopa-responsive dystonia who developed neuroleptic malignant syndrome with prolonged catatonia following treatment with neuroleptic agents. Use of these agents probably expanded the patient's neuronal dysfunction beyond the nigrostriatal system to involve multiple dopaminergic systems. Electroconvulsive treatment alleviated the prolonged catatonia.


Assuntos
Catatonia/fisiopatologia , Distonia/tratamento farmacológico , Levodopa/uso terapêutico , Síndrome Maligna Neuroléptica/fisiopatologia , Adulto , Catatonia/diagnóstico , Catatonia/terapia , Distonia/enzimologia , Distonia/genética , Eletroencefalografia/efeitos dos fármacos , Eletroencefalografia/estatística & dados numéricos , Feminino , GTP Cicloidrolase/genética , Humanos , Síndrome Maligna Neuroléptica/diagnóstico , Síndrome Maligna Neuroléptica/terapia
6.
Neurology ; 59(7): 1105-7, 2002 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-12370476

RESUMO

Nasu-Hakola disease (NHD) is an autosomal recessive disorder characterized by presenile dementia and bone cysts. Finnish patients revealed a large deletion in DAP12 gene encoding a key element for transducing activation signal. The authors examined six Japanese cases for DAP12 alleles. Five of the six had loss-of-function mutation, either a single-base deletion or a novel point mutation. The single patient without mutation normally expressed DAP12 protein. Japanese NHD has at least three genetic forms regarding DAP12.


Assuntos
Doença de Alzheimer/genética , Cistos Ósseos/genética , Heterogeneidade Genética , Proteínas Adaptadoras de Transdução de Sinal , Adulto , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Cistos Ósseos/metabolismo , Cistos Ósseos/patologia , Encéfalo/patologia , Feminino , Humanos , Masculino , Proteínas de Membrana , Mutação/genética , Receptores Imunológicos/biossíntese , Receptores Imunológicos/genética
7.
Brain ; 124(Pt 6): 1149-55, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11353731

RESUMO

In order to explore the pathophysiology of diabetic neuropathy, we studied serial changes of axonal excitability in 20 adult Wistar rats with streptozocin-induced diabetes using the technique of threshold electrotonus (TE). After persistent hyperglycaemia had developed, rats were divided into two groups: nine were fed a diet containing aldose reductase inhibitor (Epalrestat 30 mg/kg/day) (ARI(+) group) and 11 were fed a diet without the inhibitor (ARI(-) group). Eight normal control rats of similar age (NC group) were also studied. We monitored membrane properties of motor axons in the tail for 3 months using TE to measure the changes in excitability induced by subthreshold polarizing currents while recording compound muscle action potentials (CMAPs) in the tail muscle. The ARI(-) group showed a significant increase in CMAP latency 1 month after streptozocin injection, and by 3 months there was significantly lower excitability after hyperpolarization for 100 ms compared with the NC group. A similar change in TE was reproduced by injection of caesium chloride, an inhibitor of inward rectification. By contrast, the ARI(+) group exhibited no significant change in TE or latency at 3 months, although they showed significant body weight loss and hyperglycaemia. These findings indicate that inward rectification is reduced in an experimental model, as in human diabetes, and that blocking the polyol pathway with an ARI prevents this reduction. Reduced inward rectification potentiates conduction block caused by activity-dependent hyperpolarization and may underlie the decreased vibratory sensation seen in the early stage of diabetic neuropathy.


Assuntos
Potenciais de Ação/fisiologia , Axônios/metabolismo , Diabetes Mellitus Experimental/fisiopatologia , Neuropatias Diabéticas/fisiopatologia , Condução Nervosa/fisiologia , Nervos Periféricos/fisiopatologia , Animais , Axônios/patologia , Glicemia/fisiologia , Peso Corporal/fisiologia , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Neuropatias Diabéticas/metabolismo , Neuropatias Diabéticas/patologia , Estimulação Elétrica/métodos , Masculino , Nervos Periféricos/metabolismo , Nervos Periféricos/patologia , Ratos , Ratos Wistar , Tempo de Reação/fisiologia , Fatores de Tempo
8.
Surg Today ; 31(11): 1020-3, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11766074

RESUMO

We herein present a case of attenuated familial adenomatous polyposis (AFAP) with advanced rectal cancer in a 16-year-old boy. His mother and younger brother both had subcutaneous soft tissue tumors in the back and sparse-type colorectal polyposis. His mother also had dental anomalies and gastric fundic gland polyposis. The patient was admitted to our hospital for investigation of bloody stools. Barium enema and colonofiberscopy revealed advanced rectal cancer and sparse (<50) colorectal polyps. He also had dental anomalies, a subcutaneous soft tissue tumor in the back, and gastric fundic gland polyposis as extracolonic manifestations. A total proctocolectomy and ileoanal anastomosis were performed, and histological examination of the resected specimens confirmed moderately differentiated adenocarcinomas of the rectum with metastases to the regional lymph nodes. The other colorectal polyps were tubular adenomas with no evidence of malignancy. Germline mutations in the APC gene were observed in codons 486, 545, 1493, and 1556. This case serves to demonstrate that a total proctocolectomy with ileoanal anastomosis should be the procedure of choice for young patients found to have advanced rectal cancer associated with FAP.


Assuntos
Adenocarcinoma/cirurgia , Polipose Adenomatosa do Colo/cirurgia , Neoplasias Primárias Múltiplas/cirurgia , Proctocolectomia Restauradora , Neoplasias Retais/cirurgia , Adenocarcinoma/patologia , Adolescente , Anastomose Cirúrgica , Humanos , Metástase Linfática , Masculino , Neoplasias Retais/patologia
11.
J Dent Res ; 79(7): 1514-8, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11005737

RESUMO

Movement-related cortical potentials (MRCPs) are negative potentials over the scalp, which gradually increase prior to voluntary movements, and might be applied to elucidate the cortical efferent function of the mandibular movements. We compared the MRCPs accompanying various mandibular movements to study the motor control mechanism underlying these movements. Electroencephalograms (EEGs) were recorded from 11 electrodes placed over the scalp (F3, Fz, F4, T3, C3, Cz, C4, T4, P3, Pz, and P4), according to the International 10-20 System, and electromyograms (EMGs) were obtained from surface electrodes over the masseter muscle and the anterior belly of the digastric muscle. Ten healthy subjects were requested to make brisk and self-paced mandibular movements in 4 different directions (mouth-opening and -closing, and left and right lateral movements). We obtained MRCPs by averaging the EEG, using the visually determined EMG onset as a trigger signal. In all the movements, a slowly increasing, bilaterally widespread negativity starting 1.5 to 2.0 sec before the EMG onset (Bereitschaftspotential, or BP proper) was observed, with the maximum over the vertex region. The negative slope (NS') occurred about 300 to 700 msec before the EMG onset. The cortical maps of BP/NS' (BP and NS' combined), immediately prior to the mouth-opening and closing, showed a symmetrical distribution, whereas that for the lateral movements showed a tendency of predominance over the hemisphere ipsilateral to the direction of the movement. BP/NS' amplitudes at the onset of movement differed significantly or tended to do so between open, close, and lateral movements, suggesting that MRCP recordings may thus provide a means to explore the role of the cerebral cortex in the control of mandibular movements.


Assuntos
Potenciais Somatossensoriais Evocados , Mandíbula/fisiologia , Adulto , Análise de Variância , Eletroencefalografia , Eletromiografia , Eletroculografia , Potencial Evocado Motor , Lateralidade Funcional , Humanos , Masculino , Músculo Masseter/fisiologia , Movimento , Músculos do Pescoço/fisiologia
12.
Neuroreport ; 11(12): 2821-6, 2000 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-10976970

RESUMO

To investigate the origin of high-frequency somatosensory evoked potential (SEP) components, we recorded median nerve SEPs from the scalp and the depth in six monkeys. Laminar field potentials were analyzed in area 3b (N10; corresponding to human N20) and area 1 (P12; corresponding to human P25). After digital filtering (300-900 Hz), 4-6 components were identified, and the 1st to 4th peaks in area 3b (7-11 ms in latency) and the 3rd to 5th in area 1 (9-13 ms) showed clear polarity reversals between the surface and the depth of the cortex. These results provide direct evidence for intracortical origin of early high-frequency components in area 3b and of late ones in area 1.


Assuntos
Potenciais Somatossensoriais Evocados/fisiologia , Córtex Somatossensorial/fisiologia , Potenciais de Ação/fisiologia , Animais , Estimulação Elétrica , Macaca , Nervo Mediano/fisiologia , Oscilometria , Tempo de Reação/fisiologia , Couro Cabeludo/fisiologia
13.
Brain ; 123 ( Pt 9): 1813-29, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10960045

RESUMO

One characteristic of focal dystonia is the sensory trick, by which sensory input to a certain area of the body can reduce abnormal contractions in muscles nearby. This suggests that adjusting the link between sensory input and movement allows motor commands to be issued more effectively from the brain. To explore this sensorimotor link, we studied the attenuation (gating) of somatosensory evoked potentials (SEPs) before and during hand movements in patients with writer's cramp. For premovement gating, 10 patients and 11 age-matched normal subjects were given a warning sound followed 1s later by an electric stimulus to the right median nerve at the wrist. The latter served both as a reaction signal to start a finger extension task and as the input to evoke SEPs over the scalp. Because reaction times always exceeded 70 ms, short-latency SEPs thus obtained were unaffected by the afferents activated by the movement. The amplitudes of frontal N30 components were significantly decreased over the frontal leads compared with SEPs elicited at rest (P: < 0.002) in the normal group, whereas significant gating was found not for N30 but for frontal P22 (P: = 0. 002) in the patient group. For midmovement gating studies, SEPs to the right median nerve stimulation were recorded in 16 patients and 12 age-matched normal subjects at rest, and during active and passive finger extension-flexion movements. In contrast to the premovement SEPs, the frontal N30 was equally gated during active and passive movements both in the patient (P: < or = 0.002) and the normal group (P: < or = 0.003). These findings indicate that in writer's cramp the sensitivity of sensory input channels from the hand is wrongly set by the central command to move. Perhaps the sensory trick, by supplying additional input not usually present during unobstructed movement, is a manoeuvre to correct this imbalance. Dystonia may result not only from abnormalities in the central motor command but also from disturbed central processing of sensory input.


Assuntos
Distúrbios Distônicos/fisiopatologia , Potenciais Somatossensoriais Evocados/fisiologia , Movimento/fisiologia , Adulto , Idoso , Eletromiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Córtex Motor/fisiopatologia , Vias Neurais/fisiopatologia , Testes Neuropsicológicos , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Córtex Somatossensorial/fisiopatologia
14.
Diabetologia ; 43(7): 915-21, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10952465

RESUMO

AIMS/HYPOTHESIS: For use in future drug development for diabetic polyneuropathy, we conducted multicentre trials to assess the reproducibility of nerve conduction studies. METHODS: All measurements were repeated twice at a time interval of 1-4 weeks in 132 healthy subjects (63 men) and 172 patients (99 men) with diabetic polyneuropathy. Using a standardised method, 32 centres participated in the study of control subjects and 65, in patients with diabetic polyneuropathy. Motor nerve conduction studies consisted of stimulating the left median and tibial nerves and recording the compound action potential from abductor policis and adductor hallucis for measuring amplitude, terminal latency and minimal F-wave latency. For sensory conduction studies, sensory nerve action potentials were recorded antidromically from the second digit and the posterior aspect of the lateral malleous after distal stimulation of the left median and sural nerves. We also calculated motor conduction velocity, F-wave conduction velocity and sensory conduction velocity. The relative intertrial variation and intraclass correlation coefficient were used as an index of reproducibility. RESULTS: Of all the measurements, F-wave latency yielded the highest intraclass correlation coefficient with the smallest relative intertrial variation for both median and tibial nerves in both groups. CONCLUSION/INTERPRETATION: Median and tibial F-wave latency provide the most reproducible measures for a nerve conduction study, serving as one of the best measures in multicentre drug trials for diabetic polyneuropathies.


Assuntos
Neuropatias Diabéticas/fisiopatologia , Eletrofisiologia/métodos , Condução Nervosa , Adulto , Idoso , Humanos , Masculino , Nervo Mediano/fisiologia , Nervo Mediano/fisiopatologia , Pessoa de Meia-Idade , Neurônios Motores/fisiologia , Neurônios Aferentes/fisiologia , Valores de Referência , Reprodutibilidade dos Testes , Nervo Sural/fisiologia , Nervo Sural/fisiopatologia , Nervo Tibial/fisiologia , Nervo Tibial/fisiopatologia
15.
Acta Neurol Scand ; 102(1): 60-4, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10893065

RESUMO

A case of membranous lipodystrophy (Nasu-Hakola disease; NHD) associated with palilalia was reported. A 38-year-old Japanese woman developed walking difficulty in her twenties. At age 35 she manifested neuropsychiatric symptoms characterized by euphoria, palilalia and dementia. A bone marrow biopsy showed periodic acid Schiff-positive membranous cystic lesions in the adipose tissue. Positron emission tomography with (18F)-2-fluoro-2-deoxy-D-glucose disclosed that regional cerebral glucose metabolism was decreased in the bilateral frontal white matter with mild hypometabolism in the thalamus and basal ganglia; all predominantly on the right. Taken together with the previous postmortem findings, it is postulated that frontal lobe hypofunction, predominantly in the right hemisphere, produced the unique neuropsychiatric symptoms in this patient.


Assuntos
Encéfalo/metabolismo , Demência/diagnóstico por imagem , Glucose/metabolismo , Lipodistrofia/diagnóstico por imagem , Distúrbios da Fala/diagnóstico por imagem , Tomografia Computadorizada de Emissão , Adulto , Gânglios da Base/metabolismo , Gânglios da Base/fisiopatologia , Encéfalo/fisiopatologia , Demência/metabolismo , Diagnóstico Diferencial , Metabolismo Energético , Feminino , Lobo Frontal/metabolismo , Lobo Frontal/fisiopatologia , Humanos , Lipodistrofia/metabolismo , Imageamento por Ressonância Magnética , Distúrbios da Fala/metabolismo , Tálamo/metabolismo , Tálamo/fisiopatologia
16.
Brain ; 123 ( Pt 8): 1602-11, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10908190

RESUMO

Patients with multifocal motor neuropathy may complain of muscle fatigue, even though the degree of conduction block assessed at rest has improved with treatment. To explore the mechanism involved, we examined changes in muscle force during maximum voluntary contraction (MVC) and monitored conduction block before and after MVC in five patients with multifocal motor neuropathy. The results were compared with those for the contralateral unaffected homonymous muscles. For one patient, who had bilateral involvement, a normal subject of a similar age and stature served as the control. Results of conduction studies were also compared with those from six patients with amyotrophic lateral sclerosis (ALS) with similar compound muscle action potential (CMAP) amplitudes after proximal stimulation. During MVC for 60 s, the affected muscles developed prominent fatigue; the force at the end of contraction compared with the initial force was significantly lower for the affected muscles [42 +/- 19% (mean +/- standard deviation) of the initial force] than for the control muscles (94 +/- 9%; P = 0.01). After MVC, the amplitude ratio of CMAPs after proximal versus distal nerve stimulation transiently decreased to 19 +/- 14% of that before MVC in the affected muscles, but not in the control muscles (94 +/- 3.8% of that before MVC) and in patients with ALS (95 +/- 6.7%). In one patient with a focal lesion in the forearm, nerve excitability was monitored at the lesion site before and after MVC for 120 s. There were significant increases in axonal threshold (approximately 48%) and supernormality (approximately 135%) immediately after MVC, suggesting that the axonal membrane had undergone hyperpolarization and, by extrapolation, that this had precipitated the conduction block. This study is the first to show that activity-dependent conduction block plays a role in human disease by causing muscle fatigue.


Assuntos
Doença dos Neurônios Motores/fisiopatologia , Contração Muscular , Condução Nervosa , Potenciais de Ação , Adulto , Idoso , Esclerose Lateral Amiotrófica/fisiopatologia , Estimulação Elétrica , Dedos/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Fadiga Muscular , Músculo Esquelético/fisiopatologia , Polegar/fisiopatologia
17.
Brain ; 123 ( Pt 8): 1710-21, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10908200

RESUMO

To clarify the mechanism by which inhibitory motor responses such as cortical negative myoclonus are generated in humans, three patients with medically intractable partial epilepsy (two with frontal lobe epilepsy and one with parietal lobe epilepsy) were studied by means of direct cortical stimulation with a single electric pulse through subdural electrodes. All underwent chronic long-term video/EEG monitoring, cortical mapping by 50 Hz electric cortical stimulation and recording of cortical somatosensory evoked potentials with chronically implanted subdural grid electrodes (3 mm in diameter and centre-to-centre distance of 1 cm) to map both epileptogenic and functional zones. After these clinical evaluations, cortical stimulation by single electric pulse (0.3 ms duration, 1 Hz) was carried out through pairs of subdural electrodes located at the primary sensorimotor area (MI-SI), pre-supplementary motor area (pre-SMA) and lateral negative motor area (lateral NMA), while surface EMG was recorded from the muscles of the contralateral hand. The results showed that (i) in all subjects, single pulse stimulation of MI-SI elicited a motor evoked potential (MEP) followed by a silent period (SP) in the contralateral distal hand muscles, the latter lasting 300 ms after the stimulus. The duration of SP was proportional to the size of the preceding MEP. In one subject, SP without any preceding MEP was elicited, and, in another subject, there was a short SP immediately before MEP in the contralateral thenar muscle. (ii) Following the stimulation of either pre-SMA or lateral NMA, no SP was observed. It is concluded that the inhibitory mechanism within the MI-SI, but probably not in the non-primary motor areas, either closely linked to or completely independent of excitation, most likely plays an important role in eliciting brief negative motor phenomena such as cortical negative myoclonus or SP.


Assuntos
Potencial Evocado Motor , Inibição Neural , Córtex Somatossensorial/fisiopatologia , Adulto , Mapeamento Encefálico , Estimulação Elétrica/métodos , Epilepsias Parciais/etiologia , Feminino , Mãos , Humanos , Masculino , Córtex Motor/fisiopatologia , Contração Muscular , Músculo Esquelético/fisiopatologia , Mioclonia/etiologia , Descanso
18.
Muscle Nerve ; 23(5): 702-6, 2000 May.
Artigo em Inglês | MEDLINE | ID: mdl-10797392

RESUMO

We report on three patients with chronic motor neuropathy who had elevated titers of immunoglobulin (Ig)G antibodies against N-acetylgalactosaminyl GD1a (GalNAc-GD1a) and normal titers of antibodies against other gangliosides. Presenting with progressive muscular atrophy, fasciculations, and no sensory deficits, the patients had been diagnosed to have motor neuron disease. Electrodiagnostic features were predominantly axonal. Two patients clinically improved after intravenous Ig infusion and cyclophosphamide therapy. Increased titers of IgM antibodies to GalNAc-GD1a were also found in two of 15 patients with multifocal motor neuropathy with conduction block but were associated with concomitant rise of anti-GM1 antibodies. These three cases represent a chronic motor axonal neuropathy in which antibody testing for a minor ganglioside was helpful for instituting therapy.


Assuntos
Autoanticorpos/sangue , Gangliosídeos/imunologia , Doença dos Neurônios Motores/imunologia , Potenciais de Ação , Adolescente , Especificidade de Anticorpos , Ciclofosfamida/uso terapêutico , Humanos , Imunoglobulinas Intravenosas/uso terapêutico , Masculino , Pessoa de Meia-Idade , Doença dos Neurônios Motores/sangue , Doença dos Neurônios Motores/fisiopatologia , Doença dos Neurônios Motores/terapia , Condução Nervosa
19.
Muscle Nerve ; 23(4): 498-506, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10716759

RESUMO

Threshold electrotonus (TE) is a new tool for investigating axonal function noninvasively in vivo. To increase its potential clinical value, we developed a rat model of TE, and examined the effects of maturation and pharmacological intervention. We recorded TE in 92 male rats (body weight 90-650 g) by stimulating the motor nerve in the tail, and applying 100-ms conditioning currents. Motor conduction velocities increased up to a body weight of 330 g, and remained constant thereafter. TE in mature rats was similar to that in humans, and two parameters were analyzed: TEd(10-20) or the mean threshold reduction 10-20 ms after the onset of the depolarizing conditioning current at 40% of threshold intensity; and TEh(10-20) or the corresponding threshold decrease on hyperpolarization. Like latency, the absolute value of TEh(10-20) decreased up to 330 g, and then stabilized thereafter, probably reflecting the progressive increase in the axonal diameter and relative reduction in internodal impedance. In contrast, TEd(10-20) gradually decreased up to 330 g, and then jumped to a higher level, which was maintained for animals of >400 g. 4-Aminopyridine, a blocker of fast potassium channels, selectively increased TEd(10-20) only in the immature or young (<330 g) rats. This suggests that, in the mature animals, fast potassium channels become sequestrated from the nodal membrane and not activated in response to nodal depolarization. These findings indicate that mature rats (>400 g) may provide a useful experimental model for interpreting abnormal TE responses in humans, and provide evidence for nonlinear maturation of potassium channel function in myelinated axons.


Assuntos
Potenciais de Ação/fisiologia , Eletrofisiologia/métodos , Neurônios Motores/fisiologia , Desenvolvimento Muscular , Músculo Esquelético/crescimento & desenvolvimento , Condução Nervosa/fisiologia , Limiar Sensorial/fisiologia , 4-Aminopiridina/farmacologia , Potenciais de Ação/efeitos dos fármacos , Envelhecimento , Animais , Césio/farmacologia , Cloretos/farmacologia , Estimulação Elétrica , Humanos , Masculino , Neurônios Motores/efeitos dos fármacos , Tono Muscular , Músculo Esquelético/inervação , Músculo Esquelético/fisiologia , Condução Nervosa/efeitos dos fármacos , Ratos , Ratos Wistar , Tempo de Reação , Cauda/inervação
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