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1.
G Chir ; 38(5): 219-224, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29280700

RESUMO

AIM: The purpose of this paper is to evaluate the mid and long terms outcomes of open and endovascular surgical treatment, as well as multilayer stent, in patients affected by Renal Artery Aneurysm (RAA). PATIENTS AND METHODS: Twenty five patients with RAA (24 monolateral and 1 bilateral aneurysm, 26 aneurysms) were observed between 2000 and 2015: 4 were not treated due to the small size of the aneurysm (< 2.5 cm); out of the remaining, 16 underwent endovascular treatment, 2 were treated by open surgery consisting in aneurysmectomy and graft reconstruction and 5 (in 1 patient bilateral) were treated by ex vivo repair and autotransplantation. RESULTS: Out of the 22 patients treated for RAA, one patient operated upon open surgery presented an early thrombosis of a PTFE graft, followed by nephrectomy (4.7%); one patient underwent autotransplantation showed an ureteral kinking without functional consequences. In a follow-up ranging from 1 and 11 years (mean 5 years), no deaths were observed; all the renal arteries repaired were patents and 16 out of 21 patients had a significative reduction of systemic blood pressure. DISCUSSION: The choice of the best treatment is based on aneurysm's morphology according to Rundback's classification. The type I, involving the main renal artery, is always treated by endovascular approach; type II, involving renal artery bifurcations may be treated by open surgery or multilayer stents; type III (hilar or intraparenchymal aneurysms) needs only an open surgical treatment as autotransplantation. CONCLUSION: Based on our experience it seems that most of RAAs may be treated by endovascular technique. The ex vivo autotransplantation represents the first-line treatment in hilar and intraparenchymal aneurysms. Multilayer stents seem to have good outcome in the treatment of aneurysms involving arterial bifurcations. Mid and long term results, related to kidney preservation and to normalization of blood pressure, seems satisfying.


Assuntos
Aneurisma/cirurgia , Procedimentos Endovasculares , Artéria Renal/cirurgia , Stents , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Desenho de Prótese , Fatores de Tempo , Resultado do Tratamento , Procedimentos Cirúrgicos Vasculares/métodos , Adulto Jovem
3.
Minerva Cardioangiol ; 51(3): 329-35, 2003 Jun.
Artigo em Italiano | MEDLINE | ID: mdl-12867886

RESUMO

AIM: The aim of this study is to evaluate the indications for a carotid-carotid bypass and its therapeutic efficacy. METHODS: Between January 1995 and December 2001, 42 out of 782 patients with obstructive lesions of carotid vessels were submitted to carotid-carotid bypass. Preoperative investigations included Duplex scanning, transcranial Doppler and cerebral CT in all the patients, angiography in 24, spiral CT in 8, MR angiography in 6. Carotid bypass was planned pre-operatively in 13 cases due to internal carotid occlusion in 4, to pseudo-occlusion in 8 and to restenosis in 1. In the remaining 29, due to a too thin residual wall or to the lack of a good clivage plane, a carotid bypass was planned intraoperatively. A PTFE graft was employed in 30 cases while the autologous saphenous vein in 12. Four patients were lost in a 12-80-month follow-up. No intra or postoperative mortality was recorded. RESULTS: Three patients died during the follow-up. In 1 patient the death followed an ischemic stroke due to bypass occlusion. Four bypasses became occluded, in 3 cases without clinical signs. Eight patients suffered by transient superior laryngeal nerve iniury. CONCLUSIONS: Carotid bypass, as an alternative to CEA, provides good results in the treatment of the patients with carotid stenosis, pseudo-occlusion or segmental occlusion. In most of the cases the surgical technique is planned intraoperatively but in selected cases angiographic findings, spiral CT and color flow duplex can suggest in the preoperative phase that carotid bypass is the best choice.


Assuntos
Artérias Carótidas/cirurgia , Oclusão de Enxerto Vascular/epidemiologia , Humanos , Angiografia por Ressonância Magnética , Stents , Resultado do Tratamento , Procedimentos Cirúrgicos Vasculares
6.
Medicina (B Aires) ; 61(3): 279-83, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11474874

RESUMO

The objective was to evaluate the prevalence and association of several markers (islet cell antibodies: ICA, insulin autoantibodies: IAA, glutamic acid decarboxylase antibodies: GADA and ICA512 antibodies: ICA512A) along with HLA DQB1 genotype in type 1 diabetes mellitus of recent onset, including siblings and individuals without any history of this disease, in an Argentine population. A total of 79 children with type 1 diabetes mellitus of recent onset were studied, as well as 79 control children, and 68 healthy siblings of type 1 diabetic cases. IAA, ICA, GADA, ICA512A and HLA DQB1 alleles were determined. Sensitivity was 67.1% for ICA, 36.7% for IAA, 74.6% for GADA and 63.4% for ICA512A. None of the control subjects was positive for the immunological markers. Combined sensitivity of ICA-IAA-GADA was 89.8%, similar to the ICA512A-GADA (87.3%) or ICA512A-GADA-IAA combination (91.1%). GADA correlated positively with ICA, but no such correlation was found between IAA, ICA512A and ICA. IAA correlated negatively and GADA positively with age. IAA was associated to DQB1*0201, whereas ICA and ICA512A associated to DQB1*0302. Among siblings, 3/68 (4.4%) were positive for IAA and a single case (1.5%) was positive for GADA and one for ICA512A. Our findings show that the combination of multiple tests increases the sensitivity for prediction, with the ICA512A-GADA combination proving highly sensitive and equivalent to other proposed combinations, such as ICA-IAA-GADA.


Assuntos
Autoanticorpos/sangue , Diabetes Mellitus Tipo 1/imunologia , Glutamato Descarboxilase/imunologia , Antígenos HLA/imunologia , Adolescente , Adulto , Argentina , Biomarcadores , Estudos de Casos e Controles , Criança , Pré-Escolar , Diabetes Mellitus Tipo 1/genética , Feminino , Imunofluorescência , Marcadores Genéticos , Antígenos HLA/genética , Humanos , Lactente , Ilhotas Pancreáticas/imunologia , Masculino , Sensibilidade e Especificidade
7.
Minerva Cardioangiol ; 49(4): 251-6, 2001 Aug.
Artigo em Italiano | MEDLINE | ID: mdl-11426194

RESUMO

BACKGROUND: The aim of this paper is to evaluate the long term results related to surgical technique and to prosthetic material in planned and emergency conditions. METHODS: From January 1990 to December 1999, fourty-five patients with popliteal aneurysms were observed. Eighteen patients (40%) were asymptomatic; eleven (24.4%) suffered from claudicatio; six had an acute ischemia (13.3%) and four presented (8.9%) clinical signs of rest pain; in four cases (8.9%) symptoms were related to venous compression and to rupture in two (4.4%). Diagnosis was obtained by ultrasounds, angiography and CT-scan. All patients were operated on and in four cases (8.9%) the procedure involved both legs. The prosthetic material was reversed autologous saphenous vein (ASV) in 30 patients (61.2%), PTFE-EXS-TW in 16 (32.6%), homologous vein in one (2%), composite graft in one (2%), and a Dacron in the last one (2%). RESULTS: Six patients died for causes not related to the operation and eight bypasses (18.2%) became occluded. Amputation was needed in two patient, in relation to late bypass occlusion. In one cases an amputation was carried out for acute thrombosis of the contralateral aneurysm which was not treated for patients refusal. The long term patency rate was 81.8%. CONCLUSIONS: Popliteal aneurysms must be considered for reconstructive surgery, also when asymptomatic and with a diameter over 2 cm. The routinely use of the ASV improves the long-term patency rate. Best long term results are obtained in elective surgery.


Assuntos
Aneurisma/cirurgia , Artéria Poplítea/cirurgia , Procedimentos Cirúrgicos Eletivos , Emergências , Feminino , Humanos , Masculino , Fatores de Tempo
8.
Medicina [B Aires] ; 61(3): 279-83, 2001.
Artigo em Inglês | BINACIS | ID: bin-39497

RESUMO

The objective was to evaluate the prevalence and association of several markers (islet cell antibodies: ICA, insulin autoantibodies: IAA, glutamic acid decarboxylase antibodies: GADA and ICA512 antibodies: ICA512A) along with HLA DQB1 genotype in type 1 diabetes mellitus of recent onset, including siblings and individuals without any history of this disease, in an Argentine population. A total of 79 children with type 1 diabetes mellitus of recent onset were studied, as well as 79 control children, and 68 healthy siblings of type 1 diabetic cases. IAA, ICA, GADA, ICA512A and HLA DQB1 alleles were determined. Sensitivity was 67.1


for ICA, 36.7


for IAA, 74.6


for GADA and 63.4


for ICA512A. None of the control subjects was positive for the immunological markers. Combined sensitivity of ICA-IAA-GADA was 89.8


, similar to the ICA512A-GADA (87.3


) or ICA512A-GADA-IAA combination (91.1


). GADA correlated positively with ICA, but no such correlation was found between IAA, ICA512A and ICA. IAA correlated negatively and GADA positively with age. IAA was associated to DQB1*0201, whereas ICA and ICA512A associated to DQB1*0302. Among siblings, 3/68 (4.4


) were positive for IAA and a single case (1.5


) was positive for GADA and one for ICA512A. Our findings show that the combination of multiple tests increases the sensitivity for prediction, with the ICA512A-GADA combination proving highly sensitive and equivalent to other proposed combinations, such as ICA-IAA-GADA.

9.
J Cardiovasc Surg (Torino) ; 41(4): 601-5, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11052290

RESUMO

BACKGROUND: To evaluate the possibility to perform carotid surgery without angiography. METHODS: From January 1994 to June 1998, 514 patients with carotid obstructive disease were operated upon, 225 of them (43.8%) without previous angiography; 55 out of 68 (80.8%) during the last six months. Eighty-one (36.0%) had lateralizing symptoms, 50 aspecific ones (22.2%) and 94 were asymptomatic (41.8%). All patients were investigated by color-coded duplex sonography (CDS) of the arteries at the neck and by transcranial Doppler (TCD) and computed tomography (CT). One hundred eighty-eight patients were operated upon under local anaesthesia and 37 under general anesthesia; 204 had a carotid endartereotomy (90.7%) with patch angioplasty in 154 (75.5%), and 21 required a bypass graft (9.3%). In 26 patients (11.5%) an indwelling shunt was needed. RESULTS: Findings at surgery were consistent with CDS for plaque composition, ulcerations and degree of stenosis. There were no early deaths. Neurologic or ocular deficits occurred in 2 cases (0.9%). No strokes were observed in follow-up from 6 to 34 months. CONCLUSIONS: Carotid endarterectomy can be done without angiography in selected cases provided CDS plus TCD are of high quality. Under such conditions it can be considered a safer way to deal with carotid obstructive disease.


Assuntos
Artérias Carótidas/diagnóstico por imagem , Endarterectomia das Carótidas/métodos , Idoso , Estenose das Carótidas/diagnóstico por imagem , Estenose das Carótidas/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ultrassonografia Doppler em Cores , Ultrassonografia Doppler Dupla , Ultrassonografia Doppler Transcraniana
10.
Pathobiology ; 67(5-6): 245-8, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10725794

RESUMO

Macrophage activation by proinflammatory stimuli is suppressed by IL-10. We tested the hypothesis that IL-10 induces an alternative state of macrophage activation rather than solely mediating suppression. We therefore searched for genes the expression of which might be up-rather than downregulated in response to IL-10. Total RNA was obtained from mouse macrophages J774 A.1 before or after stimulation with IL-10 (20 ng/ml). Poly(A)+RNA was isolated in both cases in order to obtain driver and tester mRNA. Subtraction suppression hybridization was performed using the PCR-select cDNA subtraction procedure. After evaluation of the subtraction efficiency the subtracted cDNA library was cloned into pCRII.1. A total of 1,300 clones were obtained. Southern blot hybridization analysis was performed as the first screening step of this total number of clones. 140 (10.7%) were identified as upregulated in response to IL-10. Sequence analyses so far showed perfect or near perfect matches with already known genes for the majority of clones. Our results clearly indicate that IL-10 stimulates the expression of a large number of genes in macrophages. We conclude that IL-10 induces in macrophages a noninflammatory state of reactivity which may serve to contain proinflammatory conditions.


Assuntos
Expressão Gênica/efeitos dos fármacos , Interleucina-10/farmacologia , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Animais , Linhagem Celular , Clonagem Molecular/métodos , DNA Complementar/análise , DNA Complementar/biossíntese , Ativação de Macrófagos/genética , Macrófagos/citologia , Macrófagos/metabolismo , Camundongos , Hibridização de Ácido Nucleico/métodos , Proteínas de Ligação a Poli(A) , Reação em Cadeia da Polimerase/métodos , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Homologia de Sequência
11.
J Cardiovasc Surg (Torino) ; 40(6): 879-81, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10776722

RESUMO

A 74-year-old patient was admitted to our department in a serious general condition due to massive bleeding. He had been treated 10 years previously in another hospital with an aorto-bifemoral bypass for obstructive disease using a knitted-Dacron graft. A large pulsating mass was present in the right iliac fossa as well as enormous pulsating enlargement of the scrotum. Echo color-Doppler investigation detected dilation up to 5 cm in diameter of the right branch of the graft and a large perigraft hematoma communicating with a similar mass in the scrotum. The patient was submitted to emergency surgery and a large rupture of the graft was found. The dilated segment was resected and replaced by a new 8 mm Dacron graft. Postoperative course was uneventful.


Assuntos
Aorta Abdominal/cirurgia , Prótese Vascular , Artéria Femoral/cirurgia , Isquemia/cirurgia , Perna (Membro)/irrigação sanguínea , Polietilenotereftalatos , Falha de Prótese , Deiscência da Ferida Operatória/cirurgia , Idoso , Análise de Falha de Equipamento , Hematoma/diagnóstico , Hematoma/cirurgia , Humanos , Masculino , Escroto , Deiscência da Ferida Operatória/diagnóstico
13.
J Int Med Res ; 25(2): 98-107, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9100165

RESUMO

Ten patients affected by proximal deep venous thrombosis were treated in an open study with a low-molecular-weight dermatan sulphate (Desmin), administered at doses of 400 mg (intravenous bolus) followed by 1200 mg/day infused intravenously for 10 days, without activated partial thromboplastin adjustment. The evolution of the deep vein thrombosis and the presence of silent pulmonary embolism were evaluated by phleboscintigraphy and lung scan, performed before treatment and after 10 days of treatment, and by repeated echocolour-Doppler examination (every 2 days during treatment). The evolution of deep vein thrombosis showed a considerable improvement; similarly, lung scan showed a substantial reperfusion of lung, with regression of perfusional deficit. Repeated echocolour-Doppler examination of the deep venous system during treatment did not document further thrombus extension in any patient. Tolerance and safety were excellent. No adverse effects were observed. These preliminary results indicate that the tested dose of Desmin can be effective in treating deep vein thrombosis and silent pulmonary embolism.


Assuntos
Desmina/uso terapêutico , Veia Femoral , Veia Poplítea , Embolia Pulmonar/tratamento farmacológico , Trombose/tratamento farmacológico , Doença Aguda , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Peso Molecular , Projetos Piloto
15.
Minerva Cardioangiol ; 43(4): 161-3, 1995 Apr.
Artigo em Italiano | MEDLINE | ID: mdl-7644090

RESUMO

An aneurysms of a renal vein is very uncommon an entity and even more so when a visceral vein is affected. The venous aneurysms are generally asymptomatic and are detected either at post-mortem examination or by Echography, CT scan or MR investigation. Occasionally they become symptomatic because of rupture, thrombosis and embolism, but even in those cases they are difficult to be diagnosed and can be life threatening particularly when bleeding occurs. Exceptionally an aneurysm of a visceral vein is an unexpected intraoperative finding and is detected during an abdominal procedure undertaken for other pathology. In our experience a true aneurysm of the main trunk of the left renal vein was detected during a procedure of aorto-bifemoral by-pass graft repair for chronic aorto-iliac occlusive disease. The aneurysm was resected and the vein repaired by direct suture. Congenital weakness of the vein wall was very likely the cause as suggested by the extreme thinness and media atrophy of the aneurysm and normal appearance of the wall of renal vein and inferior vena cava. Differences between varices and aneurysms of the renal veins are discussed as well as indications for surgical treatment.


Assuntos
Aneurisma , Prótese Vascular , Veias Renais , Aneurisma/diagnóstico por imagem , Aneurisma/etiologia , Aneurisma/patologia , Aneurisma/cirurgia , Aorta Abdominal/cirurgia , Artéria Femoral/cirurgia , Humanos , Angiografia por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Veias Renais/diagnóstico por imagem , Veias Renais/patologia , Veias Renais/cirurgia , Tomografia Computadorizada por Raios X
16.
J Immunol Methods ; 169(2): 241-9, 1994 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-8133083

RESUMO

On type 1 newly diagnosed and on insulin treated diabetic patients, anti-insulin autoantibodies (IAA) and antibodies (IA) having the same specificity are respectively induced. Such immune response may be evaluated either by radiobinding assay (RBA) or enzyme-linked immunosorbent assay (ELISA). Both methodologies have been compared at previous International Workshops, which pointed out discrepancies in results. In this work, IAA/IA prevalence was assessed by displacement RBA and ELISA, in normal subjects, type 2 (treated with hypoglycaemic agents), insulin treated and newly diagnosed type 1 diabetic patients. Results showed a lack of RBA-ELISA agreement. An attempt was then made to determine whether such results were, at least in part, attributable to iodination site in Tyr-A14. For this purpose parallel RBA assays were carried out by using radiolabelled insulin at A14 and A19 Tyr residues. Control sera and samples from insulin treated and type 1 newly diagnosed diabetic patients were tested. Our results suggest that labelling position is not involved in artifactual binding of tracers, at least as a systematic phenomenon. In the majority of cases the variability in RBA-ELISA signal ratios are best explained in terms of differences in the basic principles operating in both methods instead of artifacts due to tracer preparation.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Anticorpos Anti-Insulina/imunologia , Insulina/imunologia , Radioisótopos do Iodo , Ensaio Radioligante/métodos , Tirosina , Adolescente , Adulto , Idoso , Autoanticorpos/análise , Autoanticorpos/imunologia , Sítios de Ligação de Anticorpos/imunologia , Criança , Diabetes Mellitus Tipo 1/imunologia , Diabetes Mellitus Tipo 2/imunologia , Feminino , Humanos , Anticorpos Anti-Insulina/análise , Masculino , Pessoa de Meia-Idade
17.
Neuroreport ; 5(2): 148-50, 1993 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-7509205

RESUMO

In primary cultures of rat cerebral cortex, N-methyl-D-aspartate causes widespread neurotoxicity. Inhibitors of the nitric oxide generating the enzyme nitric oxide synthase has been shown to attenuate the effects of N-methyl-D-aspartate in a number of neuronal systems both in vivo and in vitro. In our experiments, the nitric oxide synthase inhibitor N-nitroarginine was ineffective at blocking neurotoxicity induced by N-methyl-D-aspartate. Cyclic guanine monophosphate, known to be synthesized in response to nitric oxide was demonstrably inhibited by identical treatments with N-nitroarginine in sister cultures. We conclude that although nitric oxide is produced in response to N-methyl-D-aspartate, it is neither necessary nor sufficient for neurotoxicity.


Assuntos
Córtex Cerebral/citologia , N-Metilaspartato/toxicidade , Neurônios/efeitos dos fármacos , Óxido Nítrico/fisiologia , Aminoácido Oxirredutases/antagonistas & inibidores , Animais , Arginina/análogos & derivados , Arginina/farmacologia , Morte Celular/efeitos dos fármacos , Células Cultivadas , Córtex Cerebral/embriologia , GMP Cíclico/biossíntese , Modelos Neurológicos , Óxido Nítrico Sintase , Nitroarginina , Ratos
18.
Clin Immunol Immunopathol ; 66(2): 114-9, 1993 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8453783

RESUMO

Using reliable displacement radiobinding assay (RBA) and ELISA, the existence of anti-human growth hormone autoantibodies (hGHAA) was confirmed in idiopathic hypopituitary patients with growth impairment. Six of 35 hypopituitary patients (17.1%) and 1/85 (1.2%) control children proved positive for hGHAA by RBA (>control mean + 3 SD). IgG isotype-hGHAA by ELISAIgG (> control mean + 3 SD) were positive for 6/34 (17.7%) and 3/85 (3.5% hypopituitary and control children, respectively. Due to an asymmetry to the right of the ELISAIgG distribution, an alternative cutoff based on a nonparametric method was obtained, and positive results for hypopituitary children increased to 10/34 (29.4%). Three of 34 hypopituitary patients but no control children were positive for hGHAA of IgM isotype. The hGHAA were detected in children with or without perinatal problems. These autoantibodies may represent markers of a major autoimmune process involving a portion of the anterior pituitary and may contribute to the development of hypopituitarism in over 15% of hypopituitary children.


Assuntos
Autoanticorpos/sangue , Hormônio do Crescimento/imunologia , Hipopituitarismo/imunologia , Adolescente , Criança , Pré-Escolar , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Masculino , Ensaio Radioligante
19.
J Neurochem ; 59(6): 2087-93, 1992 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1359015

RESUMO

Neomycin appears as a full agonist and spermidine as a partial agonist at the site where polyamines enhance 1-[1-(2-thienyl)cyclohexyl][3H]piperidine ([3H]TCP) binding on the N-methyl-D-aspartate (NMDA) receptor. Other aminoglycosides also enhance [3H]TCP binding with efficacies roughly proportional to the number of primary amine groups. The polyamine antagonists ifenprodil and arcaine inhibit enhancement of [3H]TCP binding by spermidine or neomycin. The inhibition of [3H]TCP binding by arcaine is apparently competitively reduced by neomycin and spermidine, supporting a common site. Diethylenetriamine (previously described as a polyamine antagonist) may be a partial agonist. Enhancement by neomycin or spermidine is not additive to that of Mg2+, consistent with competition of Mg2+ and spermidine or neomycin at the site where these compounds enhance [3H]TCP binding. Polyamines also enhance the binding of the competitive antagonist 2-(2-carboxypiperazin-4-yl)[3H]propyl-1-phosphonic acid ([3H]CPP). Neomycin, which does not enhance [3H]CPP binding, inhibits the enhancement by spermidine. That this site is distinct from the site where spermidine and neomycin increase [3H]TCP binding is supported by different pharmacology. Arcaine and diethylenetriamine do not inhibit spermidine enhancement of [3H]CPP binding. Mg2+ also does not compete with the spermidine enhancement of [3H]CPP binding. Ifenprodil inhibits the spermidine enhancement of [3H]CPP binding. The data suggest two or more polyamine sites, with arcaine selective for the site that enhances [3H]TCP binding. Neomycin is an agonist at one polyamine site and antagonist to the second.


Assuntos
Neomicina/farmacologia , Poliaminas/análise , Receptores de N-Metil-D-Aspartato/química , Receptores de N-Metil-D-Aspartato/fisiologia , Antagonistas Adrenérgicos alfa/farmacologia , Animais , Biguanidas/farmacologia , Magnésio/farmacologia , Masculino , Fenciclidina/análogos & derivados , Fenciclidina/metabolismo , Piperazinas/metabolismo , Piperidinas/farmacologia , Poliaminas/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores de N-Metil-D-Aspartato/metabolismo , Espermidina/farmacologia , Membranas Sinápticas/ultraestrutura , Trítio
20.
Eur J Pharmacol ; 206(2): 155-8, 1991 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-1648501

RESUMO

omega-Conotoxin GVIA (omega-CT) has been reported to block calcium currents at the L- and N-type calcium channels. In neuronal membranes omega-CT, and the aminoglycoside antibiotic neomycin, have been shown to inhibit [125I]omega-CT binding, presumably acting at the N-type calcium channel. We demonstrate here that the concentration curve for neomycin sulfate inhibition of [125I]omega-CT binding is shifted to the right by GTP analogues or fluoride, increasing the IC50 for neomycin. [125I]omega-CT binding is unaffected by these agents and in competition studies the potency of omega-CT, Ca2+, or La3+ is not modulated by GTP analogues or fluoride. These results indicate that the inhibition of [125I]omega-CT binding by neomycin may be mediated by a GTP binding protein.


Assuntos
Proteínas de Ligação ao GTP/metabolismo , Neurônios/metabolismo , Peptídeos Cíclicos/metabolismo , Sítio Alostérico , Animais , Bloqueadores dos Canais de Cálcio/metabolismo , Canais de Cálcio/efeitos dos fármacos , Canais de Cálcio/metabolismo , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Técnicas In Vitro , Neomicina/farmacologia , Neurônios/efeitos dos fármacos , Ratos , Ratos Endogâmicos , ômega-Conotoxina GVIA
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