Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 45
Filtrar
1.
J Crohns Colitis ; 13(11): 1394-1400, 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-30994915

RESUMO

BACKGROUND AND AIMS: Inflammatory bowel disease is associated with an increased risk of colorectal cancer, with estimates ranging 2-18%, depending on the duration of colitis. The management of neoplasia in colitis remains controversial. Current guidelines recommend endoscopic resection if the lesion is clearly visible with distinct margins. Colectomy is recommended if complete endoscopic resection is not guaranteed. We aimed to assess the outcomes of all neoplastic endoscopic resections in inflammatory bowel disease. METHODS: This was a multicentre retrospective cohort study of 119 lesions of visible dysplasia in 93 patients, resected endoscopically in inflammatory bowel disease. RESULTS: A total of 6/65 [9.2%] lesions <20 mm in size were treated by ESD [endoscopic submucosal dissection] compared with 59/65 [90.8%] lesions <20 mm treated by EMR [endoscopic mucosal resection]; 16/51 [31.4%] lesions >20 mm in size were treated by EMR vs 35/51 [68.6%] by ESD. Almost all patients [97%] without fibrosis were treated by EMR, and patients with fibrosis were treated by ESD [87%], p < 0.001. In all, 49/78 [63%] lesions treated by EMR were resected en-bloc and 27/41 [65.9%] of the ESD/KAR [knife-assisted resection] cases were resected en-bloc, compared with 15/41 [36.6%] resected piecemeal. Seven recurrences occurred in the cohort. Seven complications occurred in the cohort; six were managed endoscopically and one patient with a delayed perforation underwent surgery. CONCLUSIONS: Larger lesions with fibrosis are best treated by ESD, whereas smaller lesions without fibrosis are best managed by EMR. Both EMR and ESD are feasible in the management of endoscopic resections in colitis.


Assuntos
Ressecção Endoscópica de Mucosa , Doenças Inflamatórias Intestinais/cirurgia , Mucosa Intestinal/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Neoplasias Colorretais/prevenção & controle , Europa (Continente) , Estudos de Viabilidade , Feminino , Fibrose/cirurgia , Trato Gastrointestinal/patologia , Trato Gastrointestinal/cirurgia , Humanos , Pólipos Intestinais/cirurgia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
2.
Clin Genet ; 85(2): 166-71, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23488891

RESUMO

The term 'limb-girdle myasthenia' (LGM) was first used to describe three siblings with proximal limb weakness without oculobulbar involvement, but with EMG decrement and responsiveness to anticholinesterase medication. We report here that exome sequencing in the proband of this family revealed several sequence variations in genes linked to proximal limb weakness. However, the only mutations that cosegregated with disease were an intronic IVS7-8A>G mutation and the previously reported 3'-UTR c.*22C>A mutation in GFPT1, a gene linked to LGM. A minigene assay showed that IVS7-8A>G activates an alternative splice acceptor that results in retention of the last seven nucleotides of intron 7 and a frameshift leading to a termination codon 13 nucleotides downstream from the new splice site. An anconeus muscle biopsy revealed mild reduction of the axon terminal size and postsynaptic fold simplification. The amplitudes of miniature endplate potentials and quantal release were also diminished. The DNA of the mildly affected father of the proband showed only the intronic mutation along with sequence variations in other genes potentially relevant to LGM. Thus, this study performed in the family originally described with LGM showed two GFPT1 untranslated mutations, which may cause disease by reducing GFPT1 expression and ultimately impairing protein glycosylation.


Assuntos
Exoma/genética , Glutamina-Frutose-6-Fosfato Transaminase (Isomerizante)/genética , Miastenia Gravis/genética , Síndromes Miastênicas Congênitas/genética , 4-Aminopiridina/análogos & derivados , 4-Aminopiridina/uso terapêutico , Idoso , Amifampridina , Sequência de Bases , Análise Mutacional de DNA , Eletromiografia , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Dados de Sequência Molecular , Miastenia Gravis/tratamento farmacológico , Miastenia Gravis/patologia , Síndromes Miastênicas Congênitas/tratamento farmacológico , Síndromes Miastênicas Congênitas/patologia , Neostigmina/uso terapêutico , Junção Neuromuscular/ultraestrutura , Linhagem , Reação em Cadeia da Polimerase Via Transcriptase Reversa
3.
Endoscopy ; 45(7): 585-8, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23801316

RESUMO

BACKGROUND AND STUDY AIM: Intrapapillary capillary loops (IPCLs) show distinct pattern changes corresponding to tumor progression and depth of invasion, important for in vivo characterization of superficial squamous cell carcinoma (SCC). We examined the relation between invasion depth and histopathologic IPCL diameter. PATIENTS AND METHODS: Prospectively, before lesion resection, magnification endoscopy and narrow band imaging were used to identify IPCL patterns of type V1 (corresponding to tumors limited to the mucosa; 10 patients) and type Vn (submucosally invading tumors; 10 patients). Post-resection, IPCL samples (type I [normal mucosa], n = 103; V1, n = 113; Vn, n = 100) were stained with hematoxylin & eosin, CD34, and desmin, and vessel diameter measured using light microscopy. RESULTS: Mean (standard deviation [SD]) histopathologic calibers of IPCLs of types I, V1, and Vn were significantly different, being 7.7 (2.8) µm, 21.9 (7.4) µm, and 65.2 (22.9) µm; type 1 vs. V1, P < 0.001; V1 vs. Vn, P < 0.001. CONCLUSIONS: Magnification endoscopy observation of IPCLs allows in vivo discrimination between intramucosal and submucosally invasive cancer.


Assuntos
Capilares/patologia , Carcinoma de Células Escamosas/patologia , Neoplasias Esofágicas/patologia , Esofagoscopia/métodos , Esôfago/patologia , Idoso , Carcinoma de Células Escamosas/cirurgia , Neoplasias Esofágicas/cirurgia , Esôfago/irrigação sanguínea , Esôfago/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mucosa/patologia , Mucosa/cirurgia , Invasividade Neoplásica , Estudos Prospectivos
4.
Cell Prolif ; 45(6): 557-65, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23045963

RESUMO

OBJECTIVE: 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) can affect post-translational processes, thus being responsible for decreased farnesylation and geranylgeranylation of intracellular small G proteins such as Ras, Rho and Rac, essential for cell survival and proliferation. In this regard, recent in vitro and in vivo studies suggest a possible role for both statins and farnesyl transferase inhibitors in the treatment of malignancies. Within such a context, the aim of our study was to investigate effects of either simvastatin (at concentrations of 1, 15, and 30 µm) or the farnesyl transferase inhibitor R115777 (at concentrations of 0.1, 1, and 10 µm), on two cultures of human non-small lung cancer cells, adenocarcinoma (GLC-82) and squamous (CALU-1) cell lines. In particular, we evaluated actions of these two drugs on phosphorylation of the ERK1/2 group of mitogen-activated protein kinases and on apoptosis, plus on cell numbers and morphology. MATERIALS AND METHODS: Western blotting was used to detect ERK phosphorylation, and to assess apoptosis by evaluating caspase-3 activation; apoptosis was also further assessed by terminal deoxynucleotidyl-mediated dUTP nick end labelling (TUNEL) assay. Cell counting was performed after trypan blue staining. RESULTS AND CONCLUSION: In both GLC-82 and CALU-1 cell lines, simvastatin and R115777 significantly reduced ERK phosphorylation; this effect, which reached the greatest intensity after 36 h treatment, was paralleled by a concomitant induction of apoptosis, documented by significant increase in both caspase-3 activation and TUNEL-positive cells, associated with a reduction in cell numbers. Our results thus suggest that simvastatin and R115777 may exert, in susceptible lung cancer cell phenotypes, a pro-apoptotic and anti-proliferative activity, which appears to be mediated by inhibition of the Ras/Raf/MEK/ERK signalling cascade.


Assuntos
Antineoplásicos/farmacologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Farnesiltranstransferase/antagonistas & inibidores , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Quinolonas/farmacologia , Sinvastatina/farmacologia , Apoptose/efeitos dos fármacos , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Caspase 3/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Pulmão/patologia , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Fosforilação/efeitos dos fármacos
6.
Endoscopy ; 44(3): 225-30, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22354822

RESUMO

BACKGROUND AND STUDY AIMS: Resection of submucosal tumors by means of endoscopy has been reported using a variety of techniques, but cannot be performed safely in tumors originating from the muscularis propria. Using the submucosal tunnel created by the technique of peroral endoscopic myotomy (POEM), we report the first series describing the new technique of submucosal endoscopic tumor resection (SET) for tumors of the esophagus and cardia. PATIENTS AND METHODS: SET was attempted in nine consecutive patients with tumors (size >2cm) of either the esophagus or cardia with clinical indications for lesion removal. Following creation of a submucosal tunnel from 5 cm above the tumor, as described previously, the tumor was dissected from the overlying mucosa/submucosa and then carefully removed from the muscular layer using triangle-tip and insulated-tip knives. Following specimen retrieval through the tunnel, the orifice was closed by clips. RESULTS: Of the nine patients, two had tumors that were too large (60 mm and 75 mm, respectively) to allow safe removal due to loss of endoscopic overview. All remaining tumors (maximal tumor extension 12-30 mm) could be resected safely using this method. No complications occurred and follow-up was unremarkable. On histology, all tumors were resected completely (one gastrointestinal stromal tumor, five leiomyomas). The technique had to be modified in one patient with an aberrant pancreas. CONCLUSIONS: SET is a promising new technique for selected submucosal tumors in the esophagus and cardia up to a size of 4 cm and should be studied further.


Assuntos
Neoplasias Esofágicas/cirurgia , Esofagoscopia/métodos , Mucosa Gástrica/cirurgia , Tumores do Estroma Gastrointestinal/cirurgia , Gastroscopia/métodos , Leiomioma/cirurgia , Neoplasias Gástricas/cirurgia , Adulto , Idoso , Cárdia , Neoplasias Esofágicas/patologia , Feminino , Tumores do Estroma Gastrointestinal/patologia , Humanos , Leiomioma/patologia , Masculino , Pessoa de Meia-Idade , Neoplasias Gástricas/patologia
7.
Clin Genet ; 80(5): 444-51, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21175599

RESUMO

Mutations in the plectin gene (PLEC1) cause epidermolysis bullosa simplex (EBS), which may associate with muscular dystrophy (EBS-MD) or pyloric atresia (EBS-PA). The association of EBS with congenital myasthenic syndrome (CMS) is also suspected to result from PLEC1 mutations. We report here a consanguineous patient with EBS and CMS for whom mutational analysis of PLEC1 revealed a homozygous 36 nucleotide insertion (1506_1507ins36) that results in a reduced expression of PLEC1 mRNA and plectin in the patient muscle. In addition, mutational analysis of CHRNE revealed a homozygous 1293insG, which is a well-known low-expressor receptor mutation. A skin biopsy revealed signs of EBS, and an anconeus muscle biopsy showed signs of a mild myopathy. Endplate studies showed fragmentation of endplates, postsynaptic simplification, and large collections of thread-like mitochondria. Amplitudes of miniature endplate potentials were diminished, but the endplate quantal content was actually increased. The complex phenotype presented here results from mutations in two separate genes. While the skin manifestations are because of the PLEC1 mutation, footprints of mutations in PLEC1 and CHRNE are present at the neuromuscular junction of the patient indicating that abnormalities in both genes contribute to the CMS phenotype.


Assuntos
Epidermólise Bolhosa Simples/genética , Síndromes Miastênicas Congênitas/genética , Plectina/genética , Receptores Nicotínicos/genética , Consanguinidade , Epidermólise Bolhosa Simples/complicações , Potenciais Pós-Sinápticos Excitadores/fisiologia , Feminino , Células HEK293 , Humanos , Masculino , Pessoa de Meia-Idade , Potenciais Pós-Sinápticos em Miniatura/fisiologia , Mutagênese Insercional/genética , Síndromes Miastênicas Congênitas/fisiopatologia , Junção Neuromuscular/fisiopatologia , Linhagem
8.
Int J Immunopathol Pharmacol ; 23(2): 471-9, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20646342

RESUMO

Non-typeable Haemophilus influenzae (NTHi) is one of the most frequently involved pathogens in bacterial exacerbations of chronic obstructive pulmonary disease (COPD). In the airways, the main tissue target of NTHi is bronchial epithelium, where this pathogen can further amplify the inflammatory and structural changes induced by proinflammatory cytokines such as tumour necrosis factor-alpha (TNF-alpha). Therefore, the aim of this study is to investigate, in primary cultures of human bronchial epithelial cells, the effects of NTHi on signal transduction pathways, apoptotic events and chemokine production activated by TNF-alpha. Moreover, we also evaluated the effects exerted on such cellular and molecular phenomena by a corticosteroid drug. p38 mitogen-activated protein kinase (MAPK) phosphorylation was analyzed by Western blotting, using an anti-phospho-p38 MAPK monoclonal antibody. Apoptosis was assayed by active caspase-3 expression. Interleukin-8 (IL-8/CXCL8) was detected in cell-free culture supernatants by ELISA. TNF-alpha induced a significant increase in p38 MAPK phosphorylation. NTHi was able to potentiate the stimulatory actions of TNF-alpha on caspase-3 expression and, to a lesser extent, on IL-8 secretion. These effects were significantly (P less than 0.01) inhibited by a pharmacological pre-treatment with budesonide. These results suggest that TNF-alpha is able to stimulate, via activation of p38 MAPK signalling pathway, IL-8 release and airway epithelial cell apoptosis; the latter effect can be markedly potentiated by NTHi. Furthermore, budesonide can be very effective in preventing, through inhibition of p38 MAPK phosphorylation, both structural and proinflammatory changes elicited in bronchial epithelium by TNF-alpha and NTHi.


Assuntos
Apoptose/efeitos dos fármacos , Brônquios/metabolismo , Budesonida/farmacologia , Haemophilus influenzae/fisiologia , Interleucina-8/biossíntese , Fator de Necrose Tumoral alfa/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Caspase 3/metabolismo , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Células Epiteliais/metabolismo , Humanos , Fosforilação
9.
J Med Genet ; 46(3): 203-8, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19251977

RESUMO

BACKGROUND: We describe a severe form of congenital myasthenic syndrome (CMS) associated with congenital nephrosis and ocular malformations caused by two truncating mutations in the gene encoding the laminin beta2 subunit (LAMB2). METHODS AND RESULTS: Mutational analysis in the affected patient, who has a history of a serious untoward reaction to treatment with acetylcholinesterase inhibition, revealed two frame-shifting heteroallelic mutations, a maternally inherited 1478delG and a paternally inherited 4804delC. An anconeus muscle biopsy demonstrated a profound distortion of the architecture and function of the neuromuscular junction, which was strikingly similar to that seen in mice lacking laminin beta2 subunit. The findings included: pronounced reduction of the axon terminal size with encasement of the nerve endings by Schwann cells, severe widening of the primary synaptic cleft and invasion of the synaptic space by the processes of Schwann cells, and moderate simplification of postsynaptic folds and intact expression of the endplate acetylcholinesterase. The endplate potential quantal content was notably reduced, while the frequencies and amplitudes of miniature endplate potentials were only moderately diminished and the decay phases of miniature endplate potentials were normal. Western blot analysis of muscle and kidney tissue and immunohistochemistry of kidney tissue showed no laminin beta2 expression. CONCLUSION: This case, which represents a new type of synaptic CMS, exemplifies the wide variability of phenotypes associated with LAMB2 mutations and underscores the fundamental role that laminin beta2 plays in the development of the human neuromuscular junction.


Assuntos
Laminina/genética , Mutação , Síndromes Miastênicas Congênitas/genética , Análise Mutacional de DNA , Oftalmopatias Hereditárias/genética , Feminino , Humanos , Síndromes Miastênicas Congênitas/diagnóstico , Síndromes Miastênicas Congênitas/fisiopatologia , Junção Neuromuscular/ultraestrutura , Adulto Jovem
10.
Cell Prolif ; 41(3): 393-407, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18435790

RESUMO

OBJECTIVES: Both interleukin-6 (IL-6) and transforming growth factor-beta (TGF-beta) are crucially involved in fibrotic events that characterize interstitial lung diseases (ILD). Therefore, the aim of this study was to investigate in primary cultures of normal and fibrotic human lung fibroblasts (HLF), exposed to either IL-6 or TGF-beta1, the effects on phosphorylation of mitogen-activated protein kinases (MAPK) and cell growth of IL-6 signalling inhibition, performed by the IL-6 receptor superantagonist Sant7. MATERIALS AND METHODS: MAPK phosphorylation was detected by Western blotting, HLF viability and proliferation were evaluated using the trypan blue staining and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, respectively. RESULTS: Sant7, at a concentration of 1 microg/mL, was capable of significantly inhibiting HLF proliferation and MAPK phosphorylation induced by cell exposure to IL-6 (100 ng/mL) or TGF-beta1 (10 ng/mL), whose actions were more evident in fibrotic cells. CONCLUSIONS: These findings suggest that, in HLFs derived from patients with ILDs, the proliferative mechanisms activated by TGF-beta1 are at least in part mediated by an increased release of IL-6, leading to phosphorylation-dependent MAPK activation. Such preliminary findings may thus open new therapeutic perspectives for fibrogenic ILDs, based on inhibition of signal transduction pathways stimulated by the IL-6 receptor.


Assuntos
Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Interleucina-6/análogos & derivados , Pulmão/citologia , Receptores de Interleucina-6/antagonistas & inibidores , Fator de Crescimento Transformador beta1/antagonistas & inibidores , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Fibroblastos/enzimologia , Humanos , Interleucina-6/farmacologia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Fosforilação/efeitos dos fármacos , Fator de Crescimento Transformador beta1/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
11.
Eur Respir J ; 31(1): 62-9, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17959643

RESUMO

Inflammation, oxidative stress and apoptosis, which are involved in chronic obstructive pulmonary disease (COPD) pathogenesis, may activate the p38 subgroup of mitogen-activated protein kinases (MAPKs). Therefore, the aim of the present study was to evaluate the expression of the phosphorylated, active form of p38 MAPK (phospho-p38) in the lungs of COPD patients. Surgical specimens were obtained from 18 smokers with COPD at different stages of disease severity, plus nine smoking and eight nonsmoking subjects with normal lung function. Phospho-p38+ cells were quantified by immunohistochemistry in both alveolar spaces and alveolar walls. Moreover, a Western blot analysis of phospho-p38 and total p38alpha isoform expressed by alveolar macrophages was performed. Phospho-p38+ alveolar macrophages and phospho-p38+ cells in alveolar walls were increased in patients with severe and mild/moderate COPD, compared with smoking and nonsmoking controls. Moreover, they were inversely correlated to values of forced expiratory volume in one second (FEV(1)) and FEV(1)/forced vital capacity. Western blot analysis showed that phosphorylated p38, but not the total p38alpha isoform, was specifically increased in alveolar macrophages from COPD patients. Activation of the p38 mitogen-activated protein kinase pathway appears to be involved in the pathogenesis of chronic obstructive pulmonary disease. The present findings suggest that this protein may be a suitable pharmacological target for therapeutic intervention.


Assuntos
Regulação Enzimológica da Expressão Gênica , Pulmão/patologia , Doença Pulmonar Obstrutiva Crônica/enzimologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Idoso , Apoptose , Ativação Enzimática , Feminino , Humanos , Pulmão/enzimologia , Macrófagos Alveolares/metabolismo , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Estresse Oxidativo , Fumar
12.
Pharmacol Res ; 49(3): 259-63, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-14726222

RESUMO

Non-small cell lung cancer (NSCLC) is the leading cause of cancer death in the world. Traditional chemotherapy for advanced NSCLC is often considered excessively toxic. Recent clinical trials documented that gemcitabine may represent a good therapeutical option in patients with NSCLC. Aim of our research was to retrospectively evaluate the adverse effects induced by gemcitabine in patients with NSCLC from 1 January 1997 to 31 December 2002, in clinical records of Oncology Divisions of "S. Giovanni di Dio" Hospital of Crotone, "Ospedali Riuniti" Hospital of Reggio Calabria, Hospital of Paola, and in Pneumological Oncology Division of "Mariano Santo" Hospital of Cosenza, Italy. Clinical records of patients treated with gemcitabine (1000mgm(-2) on days 1 and 8) were reviewed and following data were obtained: sex and age of the patients, histologic diagnosis and disease stage, World Health Organisation (WHO) performance status and toxic effects induced by gemcitabine. We reported that 71.6% of NSCLC patients (age range 48-77 years; 135 males, 27 females; performance status 0=53, 1=109) were eligible for our study. Side effect of gemcitabine involved gastrointestinal system (nausea, vomiting and diarrhoea) and only in the last cycles (VIII-XI) emopoiethic system (leukopenia, neutropenia, thrombocytopenia and anemia). Grade IV vomiting occurred in three patients, thrombocytopenia in two. Grade III leukopenia was observed in three patients. Other toxicities were mild. None of the patients died during chemotherapy. In conclusion, these data showed that gemcitabine present a very good tolerability in patients with NSCLC. Therefore, it could be considered as a new therapeutic agents to use as first line therapy for this disease.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Desoxicitidina/análogos & derivados , Desoxicitidina/efeitos adversos , Neoplasias Pulmonares/tratamento farmacológico , Idoso , Carcinoma Pulmonar de Células não Pequenas/sangue , Distribuição de Qui-Quadrado , Desoxicitidina/uso terapêutico , Feminino , Humanos , Neoplasias Pulmonares/sangue , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Gencitabina
13.
Neurology ; 61(12): 1743-8, 2003 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-14694040

RESUMO

OBJECTIVE: To further investigate the basis of abnormal neuromuscular transmission in two patients with congenital myasthenic syndrome associated with episodic ataxia type 2 (EA2) using stimulated single fiber EMG (SFEMG) and in vitro microelectrode studies. METHODS: Two patients with genetically characterized EA2 previously shown to have abnormal neuromuscular transmission by voluntary SFEMG were studied with stimulated SFEMG and anconeus muscle biopsy with microelectrode studies and electron microscopy of the neuromuscular junction. RESULTS: In vivo stimulated SFEMG showed signs of presynaptic failure, with jitter and blocking that improved with increased stimulation frequency. Additional evidence of presynaptic failure was provided by the in vitro microelectrode studies, which showed marked reduction of the end plate potential quantal content in both patients. Of note, the end plate potentials showed high sensitivity to N-type blockade with omega-conotoxin not seen in controls. The ultrastructural studies revealed some evidence of small nerve terminals apposed to normal or mildly overdeveloped postsynaptic membranes, suggesting an ongoing degenerative process. CONCLUSIONS: The authors demonstrated presynaptic failure of neurotransmission in patients with heterozygous nonsense mutations in CACNA1A. The contribution of non-P-type calcium channels to the process of neurotransmitter release in these patients likely represents a compensatory mechanism, which is insufficient to restore normal neuromuscular transmission.


Assuntos
Ataxia/diagnóstico , Ataxia/fisiopatologia , Síndromes Miastênicas Congênitas/diagnóstico , Síndromes Miastênicas Congênitas/fisiopatologia , Sinapses/patologia , Transmissão Sináptica/genética , Acetilcolinesterase/metabolismo , Adulto , Ataxia/complicações , Ligação Competitiva , Biópsia , Bloqueadores dos Canais de Cálcio , Canais de Cálcio/efeitos dos fármacos , Canais de Cálcio/genética , Estimulação Elétrica , Eletromiografia , Humanos , Masculino , Pessoa de Meia-Idade , Placa Motora/enzimologia , Placa Motora/fisiopatologia , Músculo Esquelético/inervação , Músculo Esquelético/patologia , Músculo Esquelético/fisiopatologia , Mutação , Síndromes Miastênicas Congênitas/complicações , Junção Neuromuscular/patologia , Junção Neuromuscular/fisiopatologia , Junção Neuromuscular/ultraestrutura , Sinapses/ultraestrutura
14.
Biochem Pharmacol ; 62(12): 1719-24, 2001 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-11755126

RESUMO

Mitogen-activated protein kinases (MAPK) play a central role in signal transduction by regulating many nuclear transcription factors involved in inflammatory, immune, and proliferative responses. The aim of this study was to investigate, in human pulmonary endothelial cells, the effects of synthetic glucocorticosteroids on activation of c-jun N-terminal kinases, extracellular signal-regulated kinases, and p38 subgroups of the MAPK family. Human microvascular endothelial cells from lung were stimulated for 2 h with either H(2)O(2) (2 mM), IL-1beta (10 ng/mL), or tumour necrosis factor-alpha (10 ng/mL). Under these conditions, a remarkable increase in the phosphorylation pattern of c-jun N-terminal kinases, extracellular signal-regulated kinases 1/2, and p38 was detected. Pretreatment for 12 h with dexamethasone (100 nM) was able to prevent phosphorylation-dependent MAPK activation in stimulated cells, without substantially affecting the expression levels of these enzymes. Our results suggest that inhibition of MAPK signaling pathways in human pulmonary endothelial cells may significantly contribute, by interfering with activation of several different transcription factors, to the antiinflammatory and immunosuppressive effects of glucocorticosteroids.


Assuntos
Dexametasona/farmacologia , Endotélio Vascular/efeitos dos fármacos , Glucocorticoides/farmacologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Células Cultivadas , Endotélio Vascular/enzimologia , Ativação Enzimática/efeitos dos fármacos , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno , Pulmão/citologia , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno , Fosforilação , Proteínas Quinases p38 Ativadas por Mitógeno
15.
J Neurol Neurosurg Psychiatry ; 65(6): 857-62, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9854961

RESUMO

Morvan's fibrillary chorea is a rare disease characterised by symptoms which include neuromyotonia, cramping, weakness, pruritus, hyperhidrosis, insomnia, and delirium. The first case of Morvan's fibrillary chorea to be associated with clinical manifestations of myasthenia gravis with thymoma, psoriasis, and atopic dermatitis is reported. Muscle histopathology disclosed chronic denervation and myopathic changes and in vitro electrophysiology demonstrated both presynaptic and postsynaptic defects in neuromuscular transmission. Serum antibodies to acetylcholine receptors, titin, N-type calcium channels, and voltage gated potassium channels were detected. Plasmapheresis, thymectomy, and long term immunosuppression induced a dramatic resolution of symptoms. The association of thymoma with other autoimmune disorders and autoantibodies, and prolonged and sustained remission with chronic immunosuppression, place Morvan's fibrillary chorea on the range of neurological diseases arising as a paraneoplastic complication of cortical thymomas.


Assuntos
Coreia/complicações , Síndromes Paraneoplásicas , Timoma/complicações , Neoplasias do Timo/complicações , Biópsia , Coreia/diagnóstico , Progressão da Doença , Eletromiografia/métodos , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Espasticidade Muscular/complicações , Músculo Esquelético/inervação , Músculo Esquelético/patologia , Rinite Alérgica Sazonal/complicações
19.
Muscle Nerve ; 20(12): 1595-7, 1997 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9390675

RESUMO

Guillain-Barré syndrome can very rarely present with acute quadripares and cranial nerve involvement resembling a locked-in state. We describe a very unusual case of fulminant neuropathy in a child who was previously exposed to vincristine. The clinical picture resembled brain death; however, electrodiagnostic studies led to the diagnosis of a peripheral neuropathy. Serial electrodiagnostic studies and pathologic findings confirmed demyelination.


Assuntos
Morte Encefálica/diagnóstico , Polirradiculoneuropatia/diagnóstico , Biópsia , Criança , Técnicas de Laboratório Clínico , Diagnóstico Diferencial , Eletrodiagnóstico , Humanos , Imunoglobulinas Intravenosas/uso terapêutico , Imageamento por Ressonância Magnética , Masculino , Polirradiculoneuropatia/terapia , Nervo Sural/patologia
20.
J Neurosci ; 17(11): 4170-9, 1997 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-9151734

RESUMO

The slow-channel congenital myasthenic syndrome (SCCMS) is a dominantly inherited disorder of neuromuscular transmission characterized by delayed closure of the skeletal muscle acetylcholine receptor (AChR) ion channel and degeneration of the neuromuscular junction. The identification of a series of AChR subunit mutations in the SCCMS supports the hypothesis that the altered kinetics of the endplate currents in this disease are attributable to inherited abnormalities of the AChR. To investigate the role of these mutant AChR subunits in the development of the synaptic degeneration seen in the SCCMS, we have studied the properties of the AChR mutation, epsilonL269F, found in a family with SCCMS, using both in vitro and in vivo expression systems. The mutation causes a sixfold increase in the open time of AChRs expressed in vitro, similar to the phenotype of other reported mutants. Transgenic mice expressing this mutant develop a syndrome that is highly reminiscent of the SCCMS. Mice have fatigability of limb muscles, electrophysiological evidence of slow AChR ion channels, and defective neuromuscular transmission. Pathologically, the motor endplates show focal accumulation of calcium and striking ultrastructural changes, including enlargement and degeneration of the subsynaptic mitochondria and nuclei. These findings clearly demonstrate the role of this mutation in the spectrum of abnormalities associated with the SCCMS and point to the subsynaptic organelles as principal targets in this disease. These transgenic mice provide a useful model for the study of excitotoxic synaptic degeneration.


Assuntos
Miastenia Gravis/genética , Miastenia Gravis/fisiopatologia , Junção Neuromuscular/patologia , Junção Neuromuscular/fisiopatologia , Organelas/patologia , Animais , Cálcio/metabolismo , Modelos Animais de Doenças , Eletromiografia , Feminino , Cinética , Camundongos , Camundongos Transgênicos , Microscopia Eletrônica , Degeneração Neural/genética , Junção Neuromuscular/ultraestrutura , Neurotoxinas/metabolismo , Oócitos/fisiologia , Técnicas de Patch-Clamp , Mutação Puntual/fisiologia , Receptores Colinérgicos/genética , Sinapses/química , Sinapses/fisiologia , Sinapses/ultraestrutura , Xenopus laevis
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA