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3.
Br J Dermatol ; 166(5): 1017-22, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22413864

RESUMO

BACKGROUND: ATP2A2 encoding the sarcoplasmic/endoplasmic reticulum Ca(2+) -ATPase2 (SERCA2) is a Darier disease (DD)-related gene. Ultraviolet (UV) B irradiation downregulates ATP2A2/SERCA2 expression in keratinocytes, whereas cyclooxygenase-2 (COX-2) expression is dramatically upregulated by UVB. OBJECTIVES: To analyse the involvement of COX-2 in ATP2A2/SERCA2 expression. METHODS: Keratinocytes were transfected with COX-2 siRNA or treated with COX-2 inhibitor, celecoxib, to evaluate the effect of COX-2 on ATP2A2/SERCA2 expression. Quantitative real-time polymerase chain reaction, Western blotting analysis and reporter assay were used to determine the amount of mRNA, protein level and transcription activity, respectively. RESULTS: COX-2 knockdown by siRNA resulted in upregulation of ATP2A2 transcription. Treatment by celecoxib rescued UVB-mediated suppression of the ATP2A2 transcription and SERCA2 protein expression. Simple addition of prostaglandin (PG) E(2) , which is a product of COX-2 enzyme, reduced the amounts of ATP2A2 mRNA and SERCA2 protein in keratinocytes. CONCLUSIONS: UVB downregulates ATP2A2/SERCA2 expression via induction of COX-2 expression and subsequent increase of PGE(2) production in keratinocytes. Considering that DD is caused by the decreased function of SERCA2 due to the reduced expression of the ATP2A2 gene, this finding shows the possibility that COX-2 inhibition may be useful to prevent and/or treat DD.


Assuntos
Inibidores de Ciclo-Oxigenase 2/farmacologia , Ciclo-Oxigenase 2/fisiologia , Doença de Darier/terapia , Queratinócitos/fisiologia , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/genética , Raios Ultravioleta , Células Cultivadas , Dinoprostona/farmacologia , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/efeitos da radiação , Técnicas de Silenciamento de Genes , Humanos , Recém-Nascido , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , RNA Interferente Pequeno/farmacologia , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo
4.
J Neuroendocrinol ; 24(5): 766-73, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22250860

RESUMO

Neuropeptide Y (NPY) is a potent orexigenic neuropeptide implicated in feeding regulation in mammals. However, except for the case of the goldfish, the involvement of NPY in the feeding behaviour of teleost fish has not well been studied. Therefore, we investigated the role of NPY in food intake using a zebrafish (Danio rerio) model because the molecular bases of NPY and its receptor have been well studied in this species. We examined the effect of feeding status on NPY-like immunoreactivity and the expression level of the NPY transcript in the brain. The number of neuronal cells showing NPY-like immunoreactivity in the hypothalamic regions, including the periventricular nucleus of posterior tuberculum and the posterior tuberal nucleus, was significantly increased in fish fasted for 7 days. NPY mRNA levels in the hypothalamus, but not the telencephalon, obtained from fish fasted for 7 days were higher than those in fish that had been fed normally. We then investigated the effect of i.c.v. administration of NPY on food intake. Cumulative food intake was significantly increased by i.c.v. administration of NPY (at 1 and 10 pmol/g body weight; BW) during a 60-min observation period. The NPY-induced orexigenic action (at 10 pmol/g BW) was blocked by treatment with a NPY Y1 receptor antagonist, BIBP-3226, at 100 pmol/g BW. These results indicate that NPY acts as an orexigenic factor in the zebrafish.


Assuntos
Ingestão de Alimentos/efeitos dos fármacos , Neuropeptídeo Y/farmacologia , Peixe-Zebra/fisiologia , Animais , Arginina/análogos & derivados , Arginina/farmacologia , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Ingestão de Alimentos/genética , Ingestão de Alimentos/fisiologia , Comportamento Alimentar/efeitos dos fármacos , Comportamento Alimentar/fisiologia , Feminino , Antagonistas de Hormônios/farmacologia , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Infusões Intraventriculares , Masculino , Neuropeptídeo Y/genética , Neuropeptídeo Y/metabolismo , Neuropeptídeo Y/fisiologia , Estado Nutricional/efeitos dos fármacos , Estado Nutricional/fisiologia , Receptores de Neuropeptídeo Y/antagonistas & inibidores , Receptores de Neuropeptídeo Y/genética , Receptores de Neuropeptídeo Y/metabolismo , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
5.
Neurology ; 62(11): 1939-44, 2004 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-15184593

RESUMO

BACKGROUND: The action mechanism of IV immunoglobulin (IVIg) for Guillain-Barré syndrome has yet to be clarified. OBJECTIVE: To evaluate clinical, histologic, and immunologic effects in a disease model of acute motor axonal neuropathy (AMAN) treated by IVIg. METHODS: Rabbits were sensitized with gangliosides including GM1 and divided randomly into two groups at disease onset. One group received IV homologous gamma-globulin (400 mg/kg/day) for 5 days (n = 15), and the other received saline (n = 15). Disease severity was scored (0 to 13 points) daily. Sixty days after onset, anti-GM1 antibodies were tested by ELISA, and the number of degenerative axons was counted in spinal anterior roots. RESULTS: Between both groups at onset, there was no difference in any characteristics including clinical score. The IVIg group had faster recovery than the saline group (p = 0.03). The percentage of rabbits that improved by a score of < or =4 was higher in the IVIg (53%) than in the saline (13%) group 60 days after onset (p = 0.03). Anti-GM1 IgG titers 60 days after onset did not differ between the groups. The anterior roots of rabbits surviving 60 days after onset showed lower frequency of axonal degeneration in the IVIg-treated (n = 11; mean 4.5%) than in the saline-treated (n = 8; mean 11.1%) rabbits (p = 0.01). CONCLUSIONS: The therapeutic efficacy of IVIg in an AMAN model was confirmed. IVIg may not affect the production or catabolism of anti-GM1 IgG, but it may prevent axonal degeneration of motor nerves.


Assuntos
Axônios/patologia , Síndrome de Guillain-Barré/terapia , Imunoglobulinas Intravenosas/uso terapêutico , Doença dos Neurônios Motores/terapia , Degeneração Neural/prevenção & controle , Animais , Modelos Animais de Doenças , Síndrome de Guillain-Barré/patologia , Masculino , Doença dos Neurônios Motores/patologia , Coelhos , Índice de Gravidade de Doença
6.
Muscle Nerve ; 24(12): 1601-6, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11745968

RESUMO

The immunosuppressant agent FK506 (tacrolimus) has proven to be neuroprotective against brain ischemia, but there are no data on potential neuroprotective effects of FK506 in peripheral nerve ischemia. We examined the potential effects of two doses of FK506 in protecting peripheral nerve from ischemic fiber degeneration. Ischemia in the left sciatic nerve of the rat was produced by injecting 2 x 10(6) microspheres (14 microm) into the left femoral, hypogastric, and superior gluteal arteries in proportions of 47%, 37%, and 17%, respectively. After embolization, FK506 was injected into the left femoral, hypogastric, and superior gluteal arteries in doses of 9.4, 7.4, and 3.4 microg, respectively, for the high-dose group and 4.7, 3.7, and 1.7 microg, respectively, for the low-dose group. The control rats were injected with saline. FK506 treatment resulted in dramatic behavioral improvement in nerve function, in the number of functioning nerve fibers, and in the salvage of a majority of nerve fibers from ischemic fiber degeneration in a dose-dependent fashion. These results suggest that a small dose of FK506 protects peripheral nerve from ischemic fiber degeneration and that it may have potential in the treatment of ischemic neuropathy.


Assuntos
Imunossupressores/farmacologia , Isquemia/tratamento farmacológico , Degeneração Neural/tratamento farmacológico , Degeneração Neural/prevenção & controle , Tacrolimo/farmacologia , Nervo Tibial/patologia , Potenciais de Ação , Animais , Comportamento Animal , Relação Dose-Resposta a Droga , Eletrofisiologia , Isquemia/patologia , Masculino , Degeneração Neural/patologia , Fibras Nervosas/patologia , Ratos , Ratos Sprague-Dawley , Fluxo Sanguíneo Regional
7.
Rinsho Shinkeigaku ; 41(1): 31-5, 2001 Jan.
Artigo em Japonês | MEDLINE | ID: mdl-11433764

RESUMO

We report a non-compromised patient with acute sensory neuropathy (ASN) developed following cytomegalovirus (CMV) hepatitis. A 67-year-old man admitted to a hospital because of acute hepatic dysfunction accompanying fever and skin eruption. One month later, when hepatic function normalized, numbness and clumsiness started acutely first in the right upper limb next to all the extremities. He found difficulty in walking in a couple of weeks. One month after the commencement of neurological illness, he was referred to us. On examination, he had sensory limb ataxia. His gait was wide-based, and Romberg sign was positive. Position sense was severely diminished in the extremities. Skin sensation was also attenuated distally, while no motor weakness was noted. Tendon reflexes were almost absent. Nerve conduction studies revealed absent sensory potentials in all but the left median nerve, in which amplitude was 5.5 microV with sensory conduction velocity of 40.7 m/s. Motor conduction studies, on the other hand, appeared normal except for a slight focal delay in the right ulnar nerve across the elbow. Mild increase in F-wave latencies was noted. A sural nerve specimen taken two months after the neurological onset showed a marked decrease in myelinated fiber density and active fiber degenerations accompanying axonal sproutings. Sjögren syndrome and paraneoplastic neuropathy were excluded serologically and by comprehensive imaging techniques. Although IgM anti-CMV antibody was not detected, serum IgG anti-CMV antibody was positive and significantly increased during the neurological illness. The intrathecal antibody synthesis of IgG anti-CMV antibody was suggested by a low serum/cerebrospinal fluid (CSF) antibody ratio and a high CSF IgG index. From these observations, it was strongly suggested that acute hepatitis and subsequent ASN were associated with CMV infection in this patient. Although some cases with post-infectious ASN have been previously reported, this is the first report of ASN preceded by CMV infection.


Assuntos
Infecções por Citomegalovirus/complicações , Doenças Desmielinizantes/etiologia , Doenças do Sistema Nervoso Periférico/etiologia , Transtornos de Sensação/etiologia , Doença Aguda , Idoso , Humanos , Masculino
8.
Ann Neurol ; 49(6): 712-20, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11409422

RESUMO

Some humans develop the axonal form of Guillain-Barré syndrome after receiving bovine brain ganglioside. On sensitization with the ganglioside mixture, all of a group of rabbits injected developed high anti-GM1 IgG antibody titers, flaccid limb weakness of acute onset, and a monophasic illness course. Pathological findings for the peripheral nerves showed predominant Wallerian-like degeneration, with neither lymphocytic infiltration nor demyelination. IgG was deposited on the axons of the anterior roots, and GM1 was proved to be present on the axons of peripheral nerves. Sensitization with purified GM1 also induced axonal neuropathy, indicating that GM1 was the immunogen in the mixture. A model of human axonal Guillain-Barré syndrome has been established that uses inoculation with a bovine brain ganglioside mixture or isolated GM1. This model may help to clarify the molecular pathogenesis of the syndrome and to develop new treatments for it.


Assuntos
Axônios/patologia , Modelos Animais de Doenças , Gangliosídeo G(M1)/imunologia , Síndrome de Guillain-Barré/imunologia , Síndrome de Guillain-Barré/patologia , Animais , Anticorpos/sangue , Anticorpos/imunologia , Especificidade de Anticorpos , Autoanticorpos/biossíntese , Autoanticorpos/imunologia , Axônios/imunologia , Bovinos , Quimiotaxia de Leucócito , Síndrome de Guillain-Barré/fisiopatologia , Imunização , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Imuno-Histoquímica , Masculino , Debilidade Muscular/imunologia , Debilidade Muscular/patologia , Debilidade Muscular/fisiopatologia , Nervos Periféricos/imunologia , Nervos Periféricos/patologia , Coelhos , Degeneração Walleriana/imunologia , Degeneração Walleriana/patologia , Degeneração Walleriana/fisiopatologia
9.
Diabetes Res Clin Pract ; 51(1): 9-20, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11137177

RESUMO

To investigate the characteristic features of diabetic neuropathy in type 2 diabetes mellitus, Otsuka Long-Evans Tokushima fatty (OLETF) rats, an animal model of human type 2 diabetes mellitus, and non-diabetic Long-Evans Tokushima Otsuka (LETO) rats were fed with or without sucrose and/or an aldose reductase inhibitor, [5-(3-thienyl) tetrazol-1-yl] acetic acid (TAT), for 24 weeks, and physiological, biochemical and morphological assessments were performed. Sucrose administration caused remarkable hyperglycemia in OLETF rats but not in LETO rats. Sucrose-fed OLETF rats demonstrated delayed nerve conduction velocity, decreased coefficient of variation of R-R interval, reduced sciatic nerve blood flow, increased platelet aggregation activity, a lower concentration of erythrocyte 2,3-diphosphoglycerate, and decreased Na+/K+-ATPase activity in sciatic nerves, compared with the non-sucrose-fed OLETF and LETO rats. TAT prevented all these deficits except hyperglycemia. Sorbitol and fructose accumulation and myo-inositol depletion in tail nerves of sucrose-fed OLETF rats were ameliorated by TAT. Myelinated fiber size and density in sural nerves of sucrose-fed OLETF rats were decreased and increased, respectively, compared with non-sucrose-fed OLETF and LETO rats. These morphological abnormalities were normalized by TAT. These observations suggest that the sucrose-fed OLETF rat developed diabetic neuropathy not only electrophysiologically but also histologically, and that an aldose reductase inhibitor, TAT, possesses therapeutic value for the treatment of diabetic neuropathy.


Assuntos
Diabetes Mellitus Tipo 2/fisiopatologia , Neuropatias Diabéticas/fisiopatologia , Sacarose Alimentar/farmacologia , Nervo Isquiático/fisiopatologia , 2,3-Difosfoglicerato/sangue , Aldeído Redutase/antagonistas & inibidores , Animais , Inibidores Enzimáticos/farmacologia , Eritrócitos/metabolismo , Humanos , Hiperglicemia/fisiopatologia , Masculino , Condução Nervosa/efeitos dos fármacos , Condução Nervosa/fisiologia , Agregação Plaquetária/efeitos dos fármacos , Ratos , Ratos Endogâmicos OLETF , Ratos Long-Evans , Fluxo Sanguíneo Regional/efeitos dos fármacos , Nervo Isquiático/irrigação sanguínea , Nervo Isquiático/efeitos dos fármacos , ATPase Trocadora de Sódio-Potássio/metabolismo , Tetrazóis/farmacologia , Tiofenos/farmacologia
10.
J Pharmacol Exp Ther ; 290(3): 1006-12, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10454471

RESUMO

The effects of natural cyclodepsipeptides (CDPs) on isolated rat cardiac tissue preparations were examined in vitro. Destruxin A, destruxin B (DB), roseotoxin B (RB), and roseocardin (RC), a novel CDP, each caused a concentration-dependent increase in the contraction force of the right atrium and the papillary and trabecular muscles of the right ventricle at 0.6 to 600 microM. RB, destruxin A, and DB did not affect the half-decay time of relaxation of the papillary muscles, but RC slightly prolonged it, although to a much lesser extent than BA 41899, a calcium sensitizer. This inotropic effect is accompanied by a prolongation of the automatic atrial contraction intervals. The RB-induced increase in the contraction force of papillary muscle was not affected by phentolamine, propranolol, pyrilamine, or cimetidine. RB- and RC-induced increases in the contraction force of papillary muscles were not affected by 3-isobutyl-1-methylxanthine or carbachol. Neither peptide changed the cyclic AMP levels in trabecular muscles. Neither RB nor RC affected the activity of Na(+),K(+)-ATPase from rat kidney. Neither RB, RC, nor DB affected the resting membrane potential or the apparent input resistance of papillary muscles. These results suggest that these CDPs produce both non-cyclic AMP-dependent positive inotropic and negative chronotropic effects.


Assuntos
Cardiotônicos/farmacologia , AMP Cíclico/fisiologia , Depsipeptídeos , Contração Miocárdica/efeitos dos fármacos , Peptídeos Cíclicos/farmacologia , Animais , Função Atrial , AMP Cíclico/metabolismo , Átrios do Coração/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Técnicas In Vitro , Rim/enzimologia , Masculino , Potenciais da Membrana/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , ATPase Trocadora de Sódio-Potássio/isolamento & purificação , ATPase Trocadora de Sódio-Potássio/metabolismo , Fatores de Tempo
11.
J Biosci Bioeng ; 87(3): 340-3, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-16232478

RESUMO

We screened for oligotrophic microorganisms capable of decreasing the concentration of ytterbium (Yb), a representative of the heavy rare-earth elements, in a culture medium. From 476 strains of oligotrophic microorganisms (grown on 1/100 diluted nutrient agar) isolated from soil and river water samples, 5 strains capable of reducing the concentration of Yb in diluted nutrient broth containing 5 ppm Yb were selected. Among them, a strain capable of reducing the concentration of all rare-earth elements to a great extent was identified as Streptomyces sp. (strain YB-1). This strain produced redish-purple pigment(s) only in the presence of rare earths, but not in that of other metals. The pigment was extracted with ethyl acetate and purified by a series of column chromatography steps. From the results of structural analysis using ultraviolet or infrared absorption spectrometry and 13C-NMR, the pigment was determined to be a kind of naphthoquinone similar to nanaomycin produced by a Streptomyces sp. These results suggested that rare earths might affect the physiological activity of this strain.

12.
FEMS Microbiol Lett ; 161(1): 75-82, 1998 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-9561733

RESUMO

We generated nonfimbriated mutants from both Vi-positive and -negative Salmonella typhi to analyze the role of type 1 fimbriae and Vi-antigen in bacterial invasion. A Vi-defective mutant of S. typhi GIFU 10007-3 was more invasive than the wild-type strain GIFU 10007. The wild-type strain expressing Vi-antigen did not agglutinate both Saccharomyces cerevisiae and human erythrocytes but Vi-defective mutants were able to agglutinate S. cerevisiae and human erythrocytes. Nonfimbriated mutants from Vi-negative GIFU 10007-3 lost the ability to adhere to S. cerevisiae but still could agglutinate human erythrocytes. The Vi-negative mutant increased secreted proteins and became 5-fold more invasive than the wild-type strain. Nonfimbriated Vi mutants became 50-120-fold more invasive than the wild-type GIFU 10007. To determine why nonfimbriated Vi mutants still agglutinate human red blood cells, we searched bacterial proteins that could bind human blood-type antigens. We finally identified a candidate 37 kDa outer membrane protein that recognized fucosyl-galactose, a structure common to blood type A, B and H antigens.


Assuntos
Sistema ABO de Grupos Sanguíneos/imunologia , Aglutinação , Antígenos de Bactérias/fisiologia , Fímbrias Bacterianas/fisiologia , Polissacarídeos Bacterianos/fisiologia , Salmonella typhi/fisiologia , Proteínas da Membrana Bacteriana Externa/metabolismo , Humanos , Mutação
13.
Antimicrob Agents Chemother ; 41(2): 298-307, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9021183

RESUMO

ER-35786 is a new parenteral 1 beta-methyl carbapenem with a broad antibacterial spectrum and a potent antipseudomonal activity. It showed high in vitro activity, comparable to those of meropenem and a new carbapenem, BO-2727, against methicillin-susceptible Staphylococcus aureus and streptococci, with MICs at which 90% of strains tested are inhibited (MIC90S) of < or = 0.39 microgram/ml. Against methicillin-resistant S. aureus, ER-35786 was the most active among the compounds tested, yet its MIC90 was 12.5 micrograms/ml. Against members of the family Enterobacteriaceae, Moraxella catarrhalis, and Haemophilus influenzae, ER-35786 inhibited 90% of strains tested at a concentration of < or = 1.56 micrograms/ml. The MIC90 of ER-35786 for Pseudomonas aeruginosa was 3.13 micrograms/ml, and the compound was more active than meropenem. In addition, the activity of ER-35786 against imipenem-, meropenem-, cefclidin-, or ceftazidime-resistant P. aeruginosa was equal to or higher than that of the most active reference compound. The in vivo activity of ER-35786 was consistent with this in vitro activity. The in vivo activity of ER-35786 was highest for systemic infection models with methicillin-resistant S. aureus and beta-lactam-resistant P. aeruginosa strains. In acute pneumonia caused by P. aeruginosa, ER-35786 produced a greater reduction in the viable cell count in the lungs than did imipenem-cilastatin or meropenem.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Infecções Bacterianas/tratamento farmacológico , Carbapenêmicos/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pirrolidinas/farmacologia , Animais , Antibacterianos/metabolismo , Antibacterianos/uso terapêutico , Bactérias/enzimologia , Bactérias/isolamento & purificação , Carbapenêmicos/metabolismo , Carbapenêmicos/uso terapêutico , Dipeptidases/metabolismo , Resistência a Múltiplos Medicamentos , Humanos , Rim/enzimologia , Masculino , Resistência a Meticilina , Camundongos , Camundongos Endogâmicos ICR , Testes de Sensibilidade Microbiana , Pneumonia Bacteriana/tratamento farmacológico , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/isolamento & purificação , Pirrolidinas/metabolismo , Pirrolidinas/uso terapêutico , Suínos , beta-Lactamases/metabolismo
14.
J Antibiot (Tokyo) ; 50(12): 1007-13, 1997 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9510906

RESUMO

A new cyclodepsipeptide, designated roseocardin, was isolated from the culture broth of Trichothecium roseum TT103. Roseotoxin B and destruxins A and B were also isolated during the same procedure. The structure of roseocardin was determined by EI-MS, NMR and X-ray crystallographic analysis. Roseocardin as well as the other cyclodepsipeptides were shown to produce positive inotropic effects on rat heart muscles.


Assuntos
Depsipeptídeos , Fungos Mitospóricos/química , Peptídeos Cíclicos/química , Peptídeos Cíclicos/isolamento & purificação , Animais , Cardiotônicos/isolamento & purificação , Cristalografia por Raios X , Coração/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Masculino , Contração Muscular/efeitos dos fármacos , Músculos/efeitos dos fármacos , Peptídeos Cíclicos/farmacologia , Ratos , Ratos Sprague-Dawley
15.
J Diabetes Complications ; 10(4): 192-200, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8835918

RESUMO

Chronic nerve conduction showing in experimental diabetic neuropathy has been associated with decreased nodal Na+ permeability and an ultrastructurally identifiable loss of axo-glial junctions, which comprise the paranodal voltage channel barrier separating nodal Na+ channels from paranodal K+ channels. In human and experimental diabetic neuropathy these structural changes of the paranodal apparatus correlate closely with the nerve conduction defect. The present immunocytochemical study of the alpha-subunit of the Na+ channel examined whether the breach of the voltage channel barrier may account for a shift in the distribution of Na+ channels explaining decreased nodal Na+ permeability. Biobreeding Wistar (BB/W) rats diabetic for 4-8 months showed a progressive redistribution of nodal Na+ channels across the paranodal barrier into the paranodal and internodal domains which was associated with chronic nerve conduction slowing. The present data suggest that structural damage to the paranodal barrier system in diabetic nerve facilitates the lateral displacement of Na+ channels from the nodal axolemma thereby diminishing their nodal density and the nodal Na+ permeability associated with the chronic nerve conduction defect in experimental diabetes. These abnormalities were prevented by the treatment with an aldose reductase inhibitor, belonging to a class of drugs that, in neuropathic patients, improves nerve-conduction velocity and repairs axo-glial dysjunction of the paranodal apparatus.


Assuntos
Aldeído Redutase/antagonistas & inibidores , Diabetes Mellitus Experimental/fisiopatologia , Neuropatias Diabéticas/prevenção & controle , Condução Nervosa/efeitos dos fármacos , Canais de Sódio/efeitos dos fármacos , Aldeído Redutase/farmacologia , Aldeído Redutase/uso terapêutico , Animais , Modelos Animais de Doenças , Imuno-Histoquímica , Masculino , Fibras Nervosas Mielinizadas/metabolismo , Fibras Nervosas Mielinizadas/ultraestrutura , Condução Nervosa/fisiologia , Coelhos , Distribuição Aleatória , Nós Neurofibrosos/metabolismo , Ratos , Ratos Endogâmicos BB , Canais de Sódio/análise , Canais de Sódio/metabolismo , Nervo Sural/metabolismo , Nervo Sural/fisiologia , Nervo Sural/ultraestrutura , Fatores de Tempo
16.
J Diabetes Complications ; 10(4): 183-91, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8835917

RESUMO

Diabetic neuropathy is characterized by progressive nerve fiber degeneration resulting in nerve fiber loss. In order to examine what role impaired nerve fiber regeneration may play in the progressive net nerve fiber loss, spontaneously diabetic biobreeding Worcester (BB/W) rats were subjected to sciatic nerve axotomy at 6 weeks of diabetes. Myelinated nerve fiber regeneration was examined morphologically and morphometrically at various time points following axotomy. The data were compared with those of axotomized control rats and diabetic rats treated with an aldose reductase inhibitor (ARI) from 1 week after onset of diabetes. Diabetic rats showed a significant attenuation of nerve fiber regeneration during the first 6 weeks following axotomy, which was normalized at 4 months postaxotomy. ARI treatment resulted in an initial burst of supranormal regeneration, which was normalized at 4 months postaxotomy. Impaired nerve fiber regeneration in diabetic rats was associated with a marked delay in preceding Wallerian degeneration and decreased phagocytic activity by macrophages, changes not demonstrated in ARI-treated diabetic rats. We propose that the impaired nerve fiber regeneration in the diabetic BB/W rat may, in part, be the result of impaired recruitment and/or function of macrophages necessary for the initiation of normal nerve fiber regeneration. The corrective effects of ARI treatment on the regenerative ability of diabetic peripheral nerve suggest that an activated polyol pathway may impact on both intrinsic and extrinsic mechanisms governing nerve fiber regeneration.


Assuntos
Aldeído Redutase/antagonistas & inibidores , Diabetes Mellitus Experimental/fisiopatologia , Regeneração Nervosa/fisiologia , Nervo Isquiático/fisiologia , Aldeído Redutase/farmacologia , Animais , Modelos Animais de Doenças , Eletrofisiologia , Masculino , Fibras Nervosas Mielinizadas/efeitos dos fármacos , Fibras Nervosas Mielinizadas/fisiologia , Regeneração Nervosa/efeitos dos fármacos , Condução Nervosa/efeitos dos fármacos , Condução Nervosa/fisiologia , Ratos , Ratos Endogâmicos BB , Nervo Isquiático/cirurgia , Nervo Isquiático/ultraestrutura , Fatores de Tempo
17.
J Clin Invest ; 97(8): 1900-7, 1996 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-8621774

RESUMO

The abnormalities underlying diabetic neuropathy appear to be multiple and involve metabolic neuronal and vasomediated defects. The accumulation of long-chain fatty acids and impaired beta-oxidation due to deficiencies in carnitine and/or its esterified derivatives, such as acetyl-L-carnitine, may have deleterious effects. In the present study, we examined, in the diabetic bio-breeding Worcester rat, the short- and long-term effects of acetyl-L-carnitine administration on peripheral nerve polyols, myoinositol, Na+/K+ -ATPase, vasoactive prostaglandins, nerve conduction velocity, and pathologic changes. Short-term prevention (4 mo) with acetyl-L-carnitine had no effects on nerve polyols, but corrected the Na+/K+ -ATPase defect and was associated with 63% prevention of the nerve conduction defect and complete prevention of structural changes. Long-term prevention (8 mo) and intervention (from 4 to 8 mo) with acetyl-L-carnitine treatment normalized nerve PGE(1) whereas 6-keto PGF(1-alpha) and PGE(2) were unaffected. In the prevention study, the conduction defect was 73% prevented and structural abnormalities attenuated. Intervention with acetyl-L-carnitine resulted in 76% recovery of the conduction defect and corrected neuropathologic changes characteristic of 4-mo diabetic rats. Acetyl-L-carnitine treatment promoted nerve fiber regeneration, which was increased two-fold compared to nontreated diabetic rats. These results demonstrate that acetyl-L-carnitine has a preventive effect on the acute Na+/- K+_ATPase defect and a preventive and corrective effect on PGE1 in chronically diabetic nerve associated with improvements of nerve conduction velocity and pathologic changes.


Assuntos
Acetilcarnitina/uso terapêutico , Neuropatias Diabéticas/prevenção & controle , 6-Cetoprostaglandina F1 alfa/metabolismo , Alprostadil/metabolismo , Animais , Neuropatias Diabéticas/fisiopatologia , Dinoprostona/metabolismo , Frutose/metabolismo , Inositol/metabolismo , Masculino , Condução Nervosa/efeitos dos fármacos , Ratos , Ratos Endogâmicos BB , Nervo Isquiático/efeitos dos fármacos , Nervo Isquiático/fisiologia , Nervo Isquiático/fisiopatologia , ATPase Trocadora de Sódio-Potássio/metabolismo , Sorbitol/metabolismo , Fatores de Tempo
18.
Am J Physiol ; 270(3 Pt 1): G411-7, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8638706

RESUMO

The pathophysiological mechanisms responsible for diabetic gastroparesis remain unclear. Diabetes mellitus occurs spontaneously in 90% of a partially inbred colony of BB/W rats. This animal model resembles human insulin-dependent diabetes and is suitable for investigating the mechanism of diabetic gastroparesis. Diabetic BB/W rats were killed 6 mo after the onset of diabetes. Muscle contraction experiments and [3H]acetylcholine release studies were performed with muscle strips of the gastric body. Biochemical measurements of inositol trisphosphate (IP3) and protein kinase C (PKC) in gastric muscle were performed to characterize abnormalities of the intracellular signal transduction system in gastric myocytes. Circular muscle contractions in response to direct myogenic stimulants, carbachol (10(-7) - 10 (-3)M) or substance P (10(-7) - 10(-5)M), were significantly impaired in diabetic BB/W rats compared with controls. Similarly, muscle contractions in response to NaF (10 mM), a direct stimulant of G proteins, were also impaired in diabetic BB/W rats. In contrast, muscle contractions in response to KCl (25-75 mM) were similar between control and diabetic BB/W rats, indicating normal voltage-dependent Ca2+ entry in muscle strips obtained from diabetics BB/W rats. [3H]acetylcholine release from gastric myenteric plexus in response to electrical transmural stimulation remained intact in diabetic BB/W rats. In separate studies, we demonstrated that carbachol (10(-6) - 10(-4)M) -induced IP3 responses were significantly reduced in diabetic rats compared with control. In addition, there was also impairment of translocation of PKC in diabetic BB/W rats. These observations indicate that myogenic impairment occurred in diabetic BB/W rats. This resulted from altered intracellular signal transduction involving abnormal IP3 production and PKC translocation.


Assuntos
Diabetes Mellitus Tipo 1/fisiopatologia , Fosfatos de Inositol/metabolismo , Músculo Liso/fisiopatologia , Transdução de Sinais , Estômago/fisiopatologia , Acetilcolina/metabolismo , Animais , Cálcio/metabolismo , Carbacol/farmacologia , Membrana Celular/metabolismo , Células Cultivadas , Citosol/metabolismo , Estimulação Elétrica , Humanos , Técnicas In Vitro , Inositol 1,4,5-Trifosfato/metabolismo , Masculino , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Músculo Liso/fisiologia , Cloreto de Potássio/farmacologia , Proteína Quinase C/metabolismo , Ratos , Ratos Endogâmicos BB , Valores de Referência , Fluoreto de Sódio/farmacologia , Estômago/efeitos dos fármacos , Estômago/fisiologia , Substância P/farmacologia , Acetato de Tetradecanoilforbol/farmacologia
19.
Acta Paediatr Jpn ; 37(2): 160-5, 1995 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-7540792

RESUMO

Ex vivo expansion of hematopoietic progenitor cells in the umbilical cord blood mononuclear cells (CB-MNC) was investigated in liquid culture system with various combinations of cytokines (stem cell factor [SCF], interleukin [IL]-3, IL-6, granulocyte-colony stimulating factor [G-CSF], erythropoietin [EPO], and interferon [INF]-gamma). Non-lineage-committed hematopoietic progenitor cells and lineage committed hematopoietic progenitor cells were represented as CD34+CD38- and CD34+CD38+ subpopulations, respectively. Although absolute CD34+CD38- cell numbers decreased even in the presence of multicytokines, the combinations of SCF plus IL-6 and SCF plus IL-3 plus IL-6 plus IFN-gamma were significantly effective in maintaining CD34+CD38- cells than the other combinations (P < 0.05). After 4 weeks of culture. CD34+CD38- cells disappeared in all combinations of cytokines. Absolute CD34+CD38+ cell numbers increased in the presence of cytokines. Maximal expansion of CD34+CD38+ cells were observed in the combinations of SCF plus IL-3 plus IL-6 plus EPO (19.8 +/- 3.3-fold) and SCF plus IL-3 plus IL-6 plus G-CSF (18.3 +/- 2.6). The combination of SCF plus IL-3 plus IL-6 was also effective to expand CD34+CD38- cells (15.8 +/- 3.9). However, the expansion was transient and they decreased to zero within 3 weeks. In the combinations of SCF plus IL-6 and SCF plus IL-3 plus IL-6 plus INF-gamma, maximal expansion was inferior to the others but CD34+CD38+ cells were maintained more than 4 weeks. These results suggested that the indication of CBT can be expanded into older children by ex vivo augmentation of CB hematopoietic progenitor cells using multi-cytokines.


Assuntos
Citocinas/farmacologia , Sangue Fetal/citologia , Transplante de Células-Tronco Hematopoéticas/métodos , Células-Tronco Hematopoéticas/efeitos dos fármacos , ADP-Ribosil Ciclase , ADP-Ribosil Ciclase 1 , Antígenos CD , Antígenos CD34 , Antígenos de Diferenciação , Humanos , Recém-Nascido , Glicoproteínas de Membrana , N-Glicosil Hidrolases , Fenótipo
20.
Acta Paediatr Jpn ; 37(1): 21-6, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7538723

RESUMO

We compared the effects of various combinations of cytokines (stem cell factor [SCF], interleukin [IL]-3, IL-6, granulocyte-colony stimulating factor [G-CSF], erythropoietin [EPO]) among the growth of human hematopoietic progenitor cells from cord blood (CB), bone marrow (BM), and peripheral blood mononuclear cells (MNC) mobilized by chemotherapy and G-CSF (PB) in a semi-solid medium. Macroscopic colonies, that were visible to the naked eye, were formed from PB-MNC within 1 week even without cytokines. They consisted of blasts containing macrophage-like cells with immature nuclei on Wright stain, and were strongly accelerated by IL-3. Macroscopic colonies were also formed from CB-MNC. However, they appeared after 1-3 weeks and synergistic effects of SCF with other cytokines, especially EPO, were prominent. Macroscopic colonies were not formed from BM-MNC. Granulocyte-colony stimulating factor was effective in increasing colony forming units of granulocyte macrophage from BM-MNC and they appeared between 1 and 2 weeks. These results suggested that the quality of hematopoietic progenitor cells was different among blood sources. This might lead to different bone marrow recovery patterns after transplantation of each blood source. The appropriate cytokines should be added to evaluate their exact potential.


Assuntos
Células da Medula Óssea , Citocinas/farmacologia , Sangue Fetal/citologia , Células-Tronco Hematopoéticas/efeitos dos fármacos , Adulto , Estudos de Casos e Controles , Criança , Fator Estimulador de Colônias de Granulócitos , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/citologia , Humanos , Recém-Nascido
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