RESUMO
Two kinds of modified infrared aural canal thermometers (Mimippi, Superthermo) are currently available in Japan. We therefore evaluated their accuracy and precision for clinical use. For the purpose of this investigation, we considered accuracy to be the mean difference between the test thermometers and the reference thermocouple. Precision was examined from the standard deviation of the difference between the test and reference values. We evaluated ten patients for cardiopulmonary bypass surgery under mild hypothermia (approximately 32 degrees C). Aural canal temperatures were measured in a random order with each infrared thermometer, and compared with readings from a thermocouple positioned at the contralateral tympanic membrane. Compared with the thermocouple, the Mimippi had regression slope 0.87 and correlation coefficient 0.79. In contrast, slope of the Superthermo regression was 0.74. The correlation coefficient for the Superthermo was 0.71. The accuracy (offset, or bias) was 0.91 degree C with the Mimippi. In contrast, it was 1.32 degrees C with the Superthermo. The precision (standard deviation) of the Mimippi was 0.65. In contrast, it was 0.73 degree C with the Superthermo. We conclude that both thermometers were moderately accurate and precise for perioperative use.
Assuntos
Temperatura Corporal , Procedimentos Cirúrgicos Cardíacos/instrumentação , Meato Acústico Externo/fisiologia , Monitorização Intraoperatória/instrumentação , Termômetros , Membrana Timpânica/fisiologia , Humanos , Raios Infravermelhos , Sensibilidade e EspecificidadeRESUMO
The mechanisms of apoptosis in neuroblastomas have been investigated by examining the expression profiles of Fas, Fas ligand (FasL), and caspase 3 in 42 primary tumour tissues. Immunohistochemically, no or weak Fas expression was detected in 25 out of 29 neuroblastomas (86 per cent), whereas high levels of expression of FasL and pro-caspase 3 were noted in 30 and 29 of 42 tumours, respectively (approximately 70 per cent). Overexpression of pro-caspase 3, but not FasL, correlated significantly with a younger age and low tumour stage. Western blot analysis of ten neuroblastomas confirmed the lack of Fas expression and the presence of strong FasL expression in all samples and pro-caspase 3 expression in five tumours, of which four belonged to the favourable type. These favourable tumours also showed vigorous Asp-Glu-Val-Asp (DEVD) hydrolytic, or caspase 3-like activities, while the unfavourable tumour lacked such activity. Moreover, immunostaining for the p17 subunit of the caspase 3 heterodimer showed that active caspase 3 was mainly localized in apoptotic tumour cells. Combined together, our results suggest that caspase 3, activated via a Fas-independent pathway, may play important roles in apoptosis, suppression of growth, and, in some cases, regression of favourable neuroblastomas.
Assuntos
Apoptose/fisiologia , Caspases/metabolismo , Neuroblastoma/fisiopatologia , Receptor fas/metabolismo , Caspase 3 , Ativação Enzimática , Precursores Enzimáticos/metabolismo , Humanos , Técnicas Imunoenzimáticas , Lactente , Ligantes , Neuroblastoma/enzimologia , Neuroblastoma/metabolismoRESUMO
BACKGROUND/PURPOSE: Fibronectin (FN) plays an important role in fibrin matrix formation during the wound healing process. The authors investigated whether exogenous FN increases the bursting strength (BS) of surgical wounds in malnourished rats. METHODS: Ninety rats were grouped according to three nutritional conditions (n = 30 in each group). All animals underwent a transverse celiotomy after 3 weeks of feeding, and FN (2 mg/body/day) was given postoperatively to 15 rats in each of the three groups. Wound BS was measured on postoperative days (PODs) 3, 5, and 7 after removal of the sutures. RESULTS: BS in normally nourished rats (group N; 142.6+/-23.4 mmHg) was significantly higher than that in protein malnourished rats (group PM, 110.2+/-11.2 mm Hg) and protein/ calorie (Cal)-malnourished rats (group PCM, 76.5+/-10.7 mm Hg) on POD 7 (P<.01). However, BS values for groups PM + FN (147.0+/-21.1 mmHg) and PCM + FN (115.1+/-28.9 mm Hg) were intensified significantly in comparison with groups PM and PCM (P<.01). Plasma FN levels in rats of the three FN nontreated groups were similarly decreased on POD 3 or 5, but returned to the preoperative level on POD 7, whereas those for the other three FN-treated groups increased after POD 3. CONCLUSION: Intravenous administration of FN might strengthen the weakened wounds of malnourished animals.
Assuntos
Fibronectinas/administração & dosagem , Distúrbios Nutricionais/complicações , Cicatrização/efeitos dos fármacos , Traumatismos Abdominais/complicações , Traumatismos Abdominais/fisiopatologia , Animais , Modelos Animais de Doenças , Feminino , Injeções Intravenosas , Distúrbios Nutricionais/fisiopatologia , Ratos , Ratos Wistar , Valores de Referência , Resultado do TratamentoRESUMO
Modified four-vessel occlusion in rats caused loss of the passive avoidance response (PAR) and impaired the radial maze performance (RMP). We investigated the effectiveness of bifemelane hydrochloride (bifemelane) in restoring these abilities. After the RMP test, the hippocampal neuronal density following cerebral ischemia was observed histologically and the effect of bifemelane on it examined. Bifemelane was intraperitoneally administered at a dose of 1, 3, 10 mg/kg or 30 mg/kg twice before ischemia and daily following cerebral ischemia. The control rats were given physiological saline in the same manner. At a dose of 10 mg/kg, i.p., bifemelane significantly restored the PAR, which had been lost as a result of 5-min ischemia. At the same dose, it significantly restored the RMP, which had been impaired by 15-min ischemia and prevented neuronal damage in the CA2 region of the anterior hippocampus and the CA1, CA2 and CA3 regions of the posterior hippocampus. The correlation between the memory score and the neuronal density in the CA1 region of the posterior hippocampus was statistically significant. These results suggest that bifemelane might prevent the neuronal damage induced by ischemia and restore impaired learning and memory capabilities following cerebrovascular disease.
Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Compostos Benzidrílicos/farmacologia , Isquemia Encefálica/psicologia , Memória/efeitos dos fármacos , Animais , Compostos Benzidrílicos/uso terapêutico , Isquemia Encefálica/patologia , Relação Dose-Resposta a Droga , Masculino , Ratos , Ratos WistarRESUMO
Serial and simultaneous measurements of the blood flow velocity of the middle cerebral artery (MCA-V) by transcranial Doppler sonography (TCD) and somatosensory evoked potentials (SEP) were performed in 7 adult patients during hypothermic cardiopulmonary bypass (CPB). CPB was instituted by alpha-stat blood gas management until the rectal temperature stabilized at 24 to 28 degrees C and gas management was converted from alpha to pH-stat by adding 4-7% of CO2 gas into the oxygenator for 10 minutes. MCA-V during hypothermic CPB by alpha-stat management was identical with normothermic prebypass MCA-V. However it significantly increased after pH-stat conversion, suggesting that CO2 reactivity was preserved even in the hypothermic situation above 24 degrees C of body temperature. Latency of all wave components of SEP and central conduction time (CCT) prolonged and wave voltages decreased as the body temperature dropped and SEP waves almost completely recovered following the temperature resumed to the prebypass temperature. There were no significant changes developed in latency and wave forms of SEP by conversion of the blood gas management from alpha-stat to pH-stat. The combined technique of TCD and SEP for detecting the real time changes of cerebral blood flow and brain function is considered to be useful to minimize the brain damage during open heart surgery.
Assuntos
Ponte Cardiopulmonar , Circulação Cerebrovascular , Potenciais Somatossensoriais Evocados , Ultrassonografia Doppler Transcraniana , Velocidade do Fluxo Sanguíneo , Ponte Cardiopulmonar/métodos , Feminino , Doenças das Valvas Cardíacas/fisiopatologia , Doenças das Valvas Cardíacas/cirurgia , Humanos , Hipotermia Induzida , Masculino , Pessoa de Meia-Idade , Monitorização IntraoperatóriaRESUMO
This study was carried out to evaluate the effect of menatetrenone, a vitamin K2 with 4 isoprene units, on prednisolone-induced bone loss. Three experiments were performed in rats which received menatetrenone as a dietary supplement. In experiment 1, a soluble form of prednisolone, dissolved in drinking water, was administered to rats at 7 mg/kg/day for 9 weeks. The length, dry weight, and bone density of femurs and tibiae, as well as urinary gamma-carboxyglutamic acid (Gla) content, were significantly lower in the prednisolone-control group than in the intact group. Menatetrenone (17 mg/kg/day) significantly inhibited the decrease in these bone parameters, especially in tibiae, and completely inhibited the decrease in urinary Gla content. In experiments 2 and 3, prednisolone (10 mg/kg), dissolved in cottonseed oil, was given to rats intramuscularly three times a week for 4 and 10 weeks, respectively. In experiment 2, bone length, bone strength and calcium content in the femur were reduced by 4-week prednisolone treatment. These reductions were significantly improved by menatetrenone (21 mg/kg/day). In experiment 3, 10-week prednisolone treatment reduced bone length and the calcium and hydroxyproline content of the femur. Menatetrenone (0.4, 10, and 50 mg/kg/day) significantly inhibited the reduction of calcium content in the femur. These results suggest that menatetrenone may inhibit the bone loss induced by corticosteroid treatment.
Assuntos
Reabsorção Óssea/prevenção & controle , Prednisolona/antagonistas & inibidores , Vitamina K/análogos & derivados , Animais , Reabsorção Óssea/sangue , Reabsorção Óssea/induzido quimicamente , Masculino , Ratos , Ratos Endogâmicos F344 , Vitamina K/farmacologia , Vitamina K 2/análogos & derivadosRESUMO
The effects of menatetrenone, a vitamin K2 homologue, on bone loss induced by ovariectomy in rats were studied in 3 experiments. Menatetrenone was given as a dietary supplement. In experiment 1, at 2 weeks postovariectomy, menatetrenone (10 mg/kg/day given for 2 weeks) inhibited the decrease in bone density of the femoral metaphysis induced by the ovariectomy. In experiment 2, menatetrenone (3 or 30 mg/kg/day given for 6 months) inhibited the decrease in bone strength of the femur and the decrease in calcium and hydroxyproline content of the femoral diaphysis at 6 months postovariectomy. In experiment 3, menatetrenone treatment, at 30 or 100 mg/kg/day for 6 months, protected against the decrease in bone strength and calcium and hydroxyproline content in the bone loss model induced by ovariectomy and calcium-deficient diet. These findings suggest that menatetrenone protects against the bone loss induced by ovariectomy.
Assuntos
Osteoporose/tratamento farmacológico , Vitamina K/análogos & derivados , Animais , Densidade Óssea/efeitos dos fármacos , Cálcio da Dieta/administração & dosagem , Feminino , Fêmur/efeitos dos fármacos , Osteoporose/etiologia , Osteoporose/prevenção & controle , Ovariectomia , Ratos , Ratos Endogâmicos F344 , Ratos Sprague-Dawley , Vitamina K/farmacologia , Vitamina K/uso terapêutico , Vitamina K 2/análogos & derivadosRESUMO
Experimental testicular dysfunction were produced by X-ray irradiation to the testes in mice. Mecobalamin (CH3-B12) was orally administered at a daily dose of 0.01, 0.1 or 1 mg/kg six times a week for 8 weeks from the next day after the irradiation. The control mice received physiological saline in the same manner. On 4th- and 6th-week after the irradiation, the weights of testes and epididymides were decreased, although those of the body and accessory sex glands (seminal vesicle, coagulating gland and prostate) were nearly equal to those of non-irradiated mice. At the same time, the diameter of seminiferous tubules decreased and sperm parameters (sperm count, sperm motility and sperm abnormality) deteriorated. When CH3-B12 (1 mg/kg) was administered, the diameter of seminiferous tubules increased and sperm parameters improved as compared to those of the control. The results indicate that CH3-B12 improved the experimental testicular dysfunction in mice induced by the irradiation. These results suggest that CH3-B12 might accelerate testicular function.
Assuntos
Lesões Experimentais por Radiação/tratamento farmacológico , Doenças Testiculares/tratamento farmacológico , Testículo/efeitos da radiação , Vitamina B 12/análogos & derivados , Administração Oral , Animais , Masculino , Camundongos , Lesões Experimentais por Radiação/fisiopatologia , Contagem de Espermatozoides , Motilidade dos Espermatozoides , Espermatogênese , Doenças Testiculares/fisiopatologia , Testículo/fisiopatologia , Vitamina B 12/administração & dosagem , Vitamina B 12/uso terapêuticoRESUMO
The spermicidal activity of menfegol-coated condoms was investigated. Menfegol (P-menthanyl-phenyl-polyxyethylene [8,8] ether) showed strong spermicidal activity at 0.5 mg/ml and higher concentrations. Semen was ejaculated directly into menfegol-coated condoms (20 mg/condom) or uncoated condoms. Immediately after ejaculation, sperm motility and viability were examined. In the menfegol-coated condoms, sperm motility was completely suppressed and no viable sperm were observed. In the uncoated condoms, most of the sperm were alive, although their motility was almost suppressed. These results indicate that the menfegol-coated condom represents a new birth control method in which the contraceptive efficacy of the condom is enhanced by the spermicidal activity of menfegol.
PIP: The spermicidal activity of menfegol-coated condoms was investigated. Menfegol (P-menthanyl-phenyl-polyxyethylene [8,8] ether) showed strong spermicidal activity at 0.5 mg/ml and higher concentration. Semen was ejaculated directly into menfegol-coated condoms (20 mg/condom) or uncoated condoms. Immediately after ejaculation, sperm motility and viability were examined. In the menfegol-coated condoms, sperm motility was completely suppressed and viable sperm were observed. In the uncoated condoms, most of the sperm were alive, although their motility was almost suppressed. These results indicate that the menfegol-coated condom represents a new birth control method in which the contraceptive efficacy of the condom is enhanced by the spermicidal activity of menfegol. (author's modified)
Assuntos
Dispositivos Anticoncepcionais Masculinos , Polietilenoglicóis/farmacologia , Espermicidas/farmacologia , Espermatozoides/efeitos dos fármacos , Humanos , Masculino , Pressão Osmótica , Contagem de Espermatozoides , Motilidade dos Espermatozoides/efeitos dos fármacos , TensoativosRESUMO
PIP: The effects of menfegol-coated condoms on sperm motility and viability were investigated. At 0.5 mg/ml and higher concentrations, mennfegol, a spermicidal agent, was found not only to suppress sperm motility buy also to kill the sperm completely, indicating that it has strong spermicidal potency. Normal semen samples were ejaculated directly into menfegol-coated or uncoated condoms. The sperm motility and viability were examined immediately after ejaculation. In the menfegol-coated condom, sperm motility was completely suppressed and no viable sperm were observed, whereas in the uncoated condom, most of the sperm were still alive, although their motility was virtually or completely suppressed. These results indicate that the menefegol-coated condom provides a new birth control method which enhances contraceptive efficacy with added spermicidal activity. (author's)^ieng
Assuntos
Preservativos , Anticoncepção , Estudos de Avaliação como Assunto , Contagem de Espermatozoides , Transporte Espermático , Espermicidas , Técnicas de Laboratório Clínico , Anticoncepcionais , Diagnóstico , Serviços de Planejamento Familiar , ReproduçãoRESUMO
The effect of Mecobalamin (alpha-(5,6-dimethyl benzimidazolyl)-Co-methyl-cobamide: Me-B 12) on sperm production in the oligozoospermic mice experimentally induced by the treatment with adriamycin (0.3 mg/kg, three times a week for 5 weeks) was evaluated quantitatively by means of equilibrium sedimentation in Percoll. After centrifugation, the distribution profile of the sperm showed two peaks, i.e. the first peak near the bottom consisting of mature sperm with good motility and the second peak containing immature and/or immotile sperm. By oral administration of Me B 12 (1.0 mg/kg/day) to the oligozoospermic mice for 10 weeks, the sperm count, sperm motility, motile sperm count, diameter of seminiferous tubules and the percentage of good motile sperm with higher apparent density were increased as compared with those of the control. These results suggest that Me-B 12 enhanced the testicular function, resulting in an increased output of mature sperm.
Assuntos
Maturação do Esperma/efeitos dos fármacos , Vitamina B 12/análogos & derivados , Animais , Centrifugação com Gradiente de Concentração , Doxorrubicina , Masculino , Camundongos , Oligospermia/induzido quimicamente , Oligospermia/tratamento farmacológico , Contagem de Espermatozoides/efeitos dos fármacos , Motilidade dos Espermatozoides/efeitos dos fármacos , Testículo/anatomia & histologia , Testículo/efeitos dos fármacos , Vitamina B 12/farmacologiaRESUMO
Experiments were performed to investigate the effects of mecobalamin (CH3-B12) on disorders of testicular function. Male rats received subcutaneously an injection of doxorubicin (ADR) three times a week for 3, 5 and 7 weeks. Thereafter, they were periodically sacrificed for the examination of cauda epididymal sperm profiles and the morphology of the testis. ADR treatment caused a decrease in sperm counts, sperm motility and the diameter of the seminiferous tubules, and an increase in the percentage of abnormal sperms. These damaging effects depended on the dosage and period of treatment with ADR. Based on these findings, rats with testicular dysfunction induced by the treatment with ADR at a daily dose of 0.25 mg/kg, three times a week for 5 weeks were prepared to investigate the effects of CH3-B12 on oligozoospermia. CH3-B12 was given intraperitoneally to the oligozoospermic rats six times a week for 5 and 10 weeks. The results obtained indicated that 1,000 micrograms/kg of CH3-B12 caused a significant increase in both the sperm counts and the diameter of the seminiferous tubules. These results suggest that CH3-B12 is a candidate drug for oligozoospermia.
Assuntos
Espermatogênese/efeitos dos fármacos , Doenças Testiculares/tratamento farmacológico , Vitamina B 12/análogos & derivados , Animais , Modelos Animais de Doenças , Doxorrubicina/administração & dosagem , Masculino , Ratos , Ratos Endogâmicos , Contagem de Espermatozoides , Motilidade dos Espermatozoides , Doenças Testiculares/induzido quimicamente , Vitamina B 12/farmacologia , Vitamina B 12/uso terapêuticoRESUMO
Analgesic and antipyretic effects of dl-2[3-(2'-chlorophenoxy)phenyl] propionic acid (CPP) were studied in mice, rats and guinea-pigs. CPP produced a dose dependent inhibition of acetic acid-induced writhing syndrome. Its ED50 values 1 and 3 hr after oral administration were 47 and 31 mg/kg, respectively. CPP had a potent analgesic effect on bradykinin-induced nociceptive response in rats, and its ED50 value was 15 mg/kg 2 hr after oral administration. The analgesic activity of CPP in these experiments was less potent than that of indomethacin, but it was approximately equivalent to ibuprofen and 10 to 20 times as potent as aspirin. CPP had no analgesic effect on both the tail pinch and hot plate tests in mice, while CPP potentiated the analgesic effect of codeine on these tests. CPP had no effect on the nociceptive response induced by intradermal injection of bradykinin and/or EDTA in guinea-pigs. On the other hand, when CPP was given orally in a dose range of 1.25 to 5 mg/kg, it produced an antipyretic effect on yeast-induced fever in rats. The antipyretic activity of CPP was equivalent to ibuprofen and 10 to 15 times as potent as aspirin.
Assuntos
Analgésicos , Anti-Inflamatórios não Esteroides , Fenilpropionatos/farmacologia , Animais , Bradicinina/farmacologia , Codeína/farmacologia , Ácido Edético/farmacologia , Febre/tratamento farmacológico , Cobaias , Masculino , Camundongos , Camundongos Endogâmicos , Ratos , Ratos EndogâmicosRESUMO
The orientation of the major coat (B) protein of the bacteriophage f1, an integral membrane protein in the cytoplasmic membrane of infected Escherichia coli, was examined. Pyridoxal 5'-phosphate and [3H]NaBH4 were used to label the cytoplasmic membrane proteins in spheroplasts and membrane vesicles of E. coli infected with bacteriophage f1. Under the conditions described, tritium incorporation was almost completely dependent on the presence of pyridoxal 5'-phosphate and little if any of the cytoplasmic proteins were labeled when the reaction was applied to intact spheroplasts. The major coat protein was isolated from the cytoplasmic membranes labeled in this manner and the chymotryptic peptides were analyzed for the presence of tritium in the pyridoxamine 5'-phosphate conjugate. When the proteins were labeled in the intact spheroplast, only the NH2-terminal chymotryptic peptide of the coat protein was labeled. If the proteins were labeled during osmotic lysis of the spheroplasts or in isolated vesicles, the chymotryptic peptide containing the COOH terminus of the coat protein as well as the NH2-terminal peptide was labeled. The NH2-terminal peptide was labeled to approximately the same extent as occurred in the intact spheroplast. These results are consistent with the hypothesis that the mature f1 coat protein asymmetrically spans the cytoplasmic membrane of the infected host with its NH2 terminus exposed on the outside and COOH terminus exposed on the cytoplasmic surface.
Assuntos
Proteínas de Bactérias/análise , Colífagos/análise , Escherichia coli/análise , Proteínas de Membrana/análise , Proteínas Virais/análise , Sequência de Aminoácidos , Boroidretos , Membrana Celular/análise , Quimotripsina , Fragmentos de Peptídeos/análise , Fosfato de Piridoxal , Esferoplastos/análiseRESUMO
The iron concentration in the growth medium was found to affect the susceptibility of Pseudomonas aeruginosa PML1550 to pyocin S2, a bacteriocin. The efficiency of killing by pyocin S2 was very low when the indicator cells were grown in an iron-rich medium. The capacity of these cells to adsorb pyocin S2 was reduced. Cultivation under limitation of iron (1 microM or less) was necessary to produce a fully sensitive cell population. The growth under iron limitation was accompanied by the appearance of four protein components in the outer membrane of the cells. Nine mutants resistant to pyocin S2 were isolated and their outer membranes were analyzed. They all lacked one component (Fe-b protein) as well as the adsorption capacity for pyocin S2. These findings suggest a possible role of this protein as the receptor for pyocin S2.
Assuntos
Bacteriocinas/farmacologia , Ferro/farmacologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Piocinas/farmacologia , Mutação , Pseudomonas aeruginosa/efeitos dos fármacos , Especificidade da EspécieRESUMO
A new esterase activity which hydrolyzes palmitoyl-CoA was found in the membrane fraction of Pseudomonas aeruginosa. All the 11 strains of P. aeruginosa tested possessed this esterase activity. The esterase was constitutive and was fully active on the intact cell bodies toward substrates in the medium. It was located on the outer membrane of the cell envelope, and was not released into the culture medium. This activity was designated as OM (outer membrane) esterase. OM esterase was solubilized from the cell envelope with EDTA-Triton X-100 and purified 690-fold. It was a minor component of the outer membrane. Its molecular weight was approximately 55,000. The activity was rather stable to heat, a wide range of pH, and treatment with detergents and organic solvents. No cofactors were required. The pH optimum of the reaction was 8.5. Among various acyl-CoAs, only long chain (C12--C18) thioesters were hydrolyzed. OM esterase also hydrolyzed some kinds of oxy-esters such as p-nitrophenyl acyl esters, monoacyl esters of sucrose and Tween 80 (polyoxyethylene sorbitan monooleate). On the other hand, triglycerides, phospholipids, or hydrophobic monoesters were not hydrolyzed at all. Thus, this enzyme seems to have specificity for long chain acyl esters with hydrophilic groups, whether thio- or oxy-ester. Mutants deficient in this esterase activity were isolated. These mutants were unable to grow on Tween 80 as a sole carbon source. This suggests a possible role of OM esterase in the utilization of acyl esters as carbon sources.
Assuntos
Acil Coenzima A/metabolismo , Membrana Celular/enzimologia , Pseudomonas aeruginosa/enzimologia , Tioléster Hidrolases/isolamento & purificação , Esterases/isolamento & purificação , Concentração de Íons de Hidrogênio , Peso Molecular , Mutação , Palmitoil Coenzima A , Polietilenoglicóis , Polissorbatos , Especificidade por SubstratoRESUMO
Experiments were performed to investigate the effects of Vitamin B12, i.e., methylcobalamin and cobamide, on the neural degeneration and regeneration. Male Wistar rats (140 to 150 g) under conditions of experimental unilateral sciatic nerve crushing were treated consecutively with methylcobalamin (50 and 500 mug/kg/day i.p.), cobamide (50 and 500 mug/kg/day i.p.) or saline. EMG recordings were periodically carried out and rats of each group were sacrificed to determine the weight-loss of denervated muscles 1, 2, 3 and 4 weeks after crush. Neither methylcobalamin nor cobamide exerted any significant effect on body-weight gain of the nerve-crushed rats with a daily injection of 50 and 500 mug/kg i.p.. The EMG pattern of the denervated biceps femoris muscle showed a total lack of fibrillation for 2 days after the nerve-crush. Thereafter, the fibrillation appeared and continued for 10 to 14 days until the nerve had regenerated, as evidenced by the appearance of a complex NMU voltage. The occurrence of fibrillation voltage was slightly delayed in methylcobalamin group (500 mug/kg/day) as compared with the saline control group. The re-appearance of normal NMU voltage was more rapid in the methylcobalamin 500 mug/kg group than in controls and other experimental groups. Neither methylcobalamin nor cobamide had any significant effect on the weight-loss of the gastrocnemius and tibialis anterior muscles following crush of the sciatic nerve. However, a daily injection of 500 mug/kg of methylcobalamin produced a significant increase in the weight of the soleus muscle which recovered to the extent of being the same weight of the contralateral 4 weeks after the nerve-crush. These results suggest that methylcobalamin may have an inhibitory effect on Wallerian degeneration and also a facilitatory effect on the neural regeneration of the crushed sciatic nerve of rats.
Assuntos
Cobamidas/farmacologia , Eletromiografia , Degeneração Neural/efeitos dos fármacos , Regeneração Nervosa/efeitos dos fármacos , Vitamina B 12/farmacologia , Animais , Cobamidas/administração & dosagem , Masculino , Denervação Muscular , Músculos/anatomia & histologia , Tamanho do Órgão , Ratos , Nervo Isquiático/lesões , Vitamina B 12/administração & dosagemRESUMO
Male Wistar rats (140 to 150 g) in which the unilateral sciatic nerve had been crushed were treated consecutively with methylcobalamin (5, 50 and 500 mug/kg/day i.p.) or saline immediately after the nerve-crush. Thereafter, they were periodically sacrificed for biochemical and histological examinations. At different intervals after the nerve-crush, L-leucine-4,5-T (20 mu Ci/100g, specific activity 15 mCi/m mole) or L-leucine -14C(U) (15 muCi/100g, specific activity 270 mCi/m mole) was given i.p. to some rats of each group and 3 hr later they were sacrificed to determine the rate of leucine incorporation into protein fractions of the crushed nerve and the denervated muscles. The nerve and muscles of the contralateral side served as control. Longitudinal sections of proximal and distal stumps of the sciatic nerve were prepared and stained with hematoxylin and eosin. As compared with saline group, repeated injections of 5, 50 and 500 mug/kg/day of methyl-cobalamin caused a significant increase of the in vivo incorporation of radioactive leucine into the protein fraction of the crushed sciatic nerve 5 to 7 days after the crush. In contrast, a recovery of the increased incorporation of leucine into the crushed nerve was more rapid in methylcobalamin groups than in the saline group. On the other hand, methylcobalamin (5 approximately 500 mug/kg/day i.p.) had no significant effect on the leucine incorporation into the denervated muscles (m. gastrocnemius, m. tibialis anterior and m. soleus). In addition, consecutive injections of methylcobalamin (5 approximately 500 mug/kg/day) did not affect the mitosis of Schwann cells during the period of Wallerian degeneration of the crushed sciatic nerve. These results suggest that methylcobalamin possesses a stimulating effect on proteosynthesis in Schwann cells at the initial stage of axon regeneration and it may facilitate neural regeneration.