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1.
BMC Neurol ; 22(1): 403, 2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36324091

RESUMO

BACKGROUND: Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) and mild encephalopathy associated with excitotoxicity (MEEX) are the most frequent acute encephalopathies in pediatric patients in Japan. AESD typically presents with biphasic seizures and delayed reduced diffusion in the subcortical area, called bright tree appearance (BTA), on radiological examination. In patients with AESD, arterial spin labeling (ASL) shows decreased cerebral blood flow (CBF) in the hyperacute stage and increased CBF in the acute stage, suggesting the usefulness of ASL for the early diagnosis of AESD. Additionally, proton magnetic resonance spectroscopy (MRS) shows elevated glutamate (Glu) and glutamine (Gln) in AESD. MEEX is a group of mild encephalopathies with transient elevation of Gln on MRS similar to that in AESD; however, MEEX does not include any clinical biphasic course or abnormalities, including BTA on diffusion-weighted imaging. Although the usefulness of ASL for AESD has been reported, there are no reports for patients with MEEX. In this study, we report our experience with a 4-year-old girl diagnosed with MEEX who showed unique findings on ASL. CASE PRESENTATION: The patient was a 4-year-old girl admitted to the emergency room with febrile status epilepticus. Considering the possibility of AESD, vitamin therapy was initiated. ASL-MR imaging (MRI) of the brain performed on the second day showed increased blood flow in the frontal, temporal, and occipital regions with spared central sulcus, which indicated AESD with central sparing. The patient was diagnosed with AESD, and the treatment included pulse steroid therapy and immunoglobulin therapy from day 3. The patient remained mildly unconscious but gradually became conscious by day 7 with no seizures. Brain MRI performed on day 8 did not show any characteristic AESD findings, such as BTA. Furthermore, MRS showed elevated Gln, which, along with the clinical course, led to the diagnosis of MEEX. The patient was discharged on day 16 without obvious sequelae. CONCLUSIONS: ASL may be useful in the early diagnosis of MEEX as well as AESD, facilitating early intervention.


Assuntos
Encefalopatias , Convulsões Febris , Feminino , Humanos , Criança , Lactente , Pré-Escolar , Marcadores de Spin , Encefalopatias/diagnóstico por imagem , Circulação Cerebrovascular , Imagem de Difusão por Ressonância Magnética , Convulsões Febris/diagnóstico , Glutamina
2.
BMC Infect Dis ; 20(1): 388, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32487032

RESUMO

BACKGROUND: Neurogenic pulmonary edema is a rare but serious complication of febrile status epilepticus in children. Comprehensive screening for viral pathogens is seldomly performed in the work-up of febrile children. CASE PRESENTATION: A 22-month-old girl presented with her first episode of febrile status epilepticus, after which she developed acute pulmonary edema and respiratory failure. After the termination of seizure activity, the patient was intubated and managed on mechanical ventilation in the emergency room. The resolution of respiratory failure, as well as the neurological recovery, was achieved 9 h after admission, and the patient was discharged 6 days after admission without any complications. Molecular biological diagnostic methods identified the presence of human coronavirus HKU1, influenza C virus, and human parainfluenza virus 2 from the patient's nasopharyngeal specimens. CONCLUSIONS: Neurogenic pulmonary edema following febrile status epilepticus was suspected to be the etiology of our patient's acute pulmonary edema and respiratory failure. Timely seizure termination and rapid airway and respiratory intervention resulted in favorable outcomes of the patient. Molecular biological diagnostic methods identified three respiratory viruses; however, their relevance and association with clinical symptoms remain speculative.


Assuntos
Edema Pulmonar/etiologia , Infecções Respiratórias/virologia , Doenças do Sistema Nervoso Central/etiologia , Doenças do Sistema Nervoso Central/terapia , Coronavirus/isolamento & purificação , Infecções por Coronavirus , Feminino , Febre/complicações , Humanos , Lactente , Influenza Humana , Gammainfluenzavirus/isolamento & purificação , Técnicas de Diagnóstico Molecular , Nasofaringe/virologia , Vírus da Parainfluenza 2 Humana/isolamento & purificação , Edema Pulmonar/diagnóstico por imagem , Edema Pulmonar/terapia , Infecções Respiratórias/complicações , Estado Epiléptico
3.
BMC Infect Dis ; 17(1): 774, 2017 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-29254479

RESUMO

BACKGROUND: Streptococcus pyogenes (group A Streptococcus [GAS]) is a major human pathogen that causes a wide spectrum of clinical manifestations. Although invasive GAS (iGAS) infections are relatively uncommon, emm3/ST15 GAS is a highly virulent, invasive, and pathogenic strain. Global molecular epidemiology analysis has suggested that the frequency of emm3 GAS has been recently increasing. CASE PRESENTATION: A 14-year-old patient was diagnosed with streptococcal toxic shock syndrome and severe pneumonia, impaired renal function, and rhabdomyolysis. GAS was isolated from a culture of endotracheal aspirates and designated as KS030. Comparative genome analysis suggested that KS030 is classified as emm3 (emm-type) and ST15 (multilocus sequencing typing [MLST]), which is similar to iGAS isolates identified in the UK (2013) and Switzerland (2015). CONCLUSIONS: We conclude that the global dissemination of emm3/ST15 GAS strain has the potential to cause invasive disease.


Assuntos
Choque Séptico/microbiologia , Infecções Estreptocócicas/microbiologia , Streptococcus pyogenes/isolamento & purificação , Antígenos de Bactérias/genética , Proteínas da Membrana Bacteriana Externa/genética , Humanos , Epidemiologia Molecular , Tipagem de Sequências Multilocus , Choque Séptico/epidemiologia , Infecções Estreptocócicas/epidemiologia , Streptococcus pyogenes/classificação , Streptococcus pyogenes/genética , Suíça/epidemiologia
4.
Pediatr Int ; 57(4): 729-31, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25919892

RESUMO

A 3-year-old boy was referred for cardiac tumor diagnosed on transthoracic echocardiography (TTE) at another hospital. The tumor appeared to be in the right atrium and obstructed inferior vena cava flow. TTE, enhanced computed tomography (CT) and angiography were done to confirm diagnosis. Subsequently, cardiac tumor was ruled out and he was diagnosed with a very rare condition of hepatic hernia containing a normal left lobe. When cardiac tumor is suspected in the right atrium on the basis of TTE, enhanced CT or magnetic resonance imaging should be done for definitive diagnosis.


Assuntos
Neoplasias Cardíacas/diagnóstico por imagem , Hérnia/diagnóstico por imagem , Hepatopatias/diagnóstico por imagem , Pré-Escolar , Angiografia por Tomografia Computadorizada , Diagnóstico Diferencial , Ecocardiografia , Humanos , Masculino
5.
Eur J Pediatr ; 172(11): 1521-6, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23812512

RESUMO

UNLABELLED: Propranolol hydrochloride is a nonselective ß-blocker that is used for the treatment of hypertension, arrhythmia, and angina pectoris. In Japan, it was recently approved for the treatment of childhood arrhythmia. It has been observed to produce drastic involution of infantile hemangiomas. The aim of this prospective study was to examine propranolol's superiority to classical therapy with pulsed dye laser and/or cryosurgery in treating proliferating infantile hemangiomas. Fifteen patients between the ages of 1 and 4 months with proliferating infantile hemangiomas received grinded propranolol tablets 2 mg/kg per day divided in three doses. Twelve patients with proliferating infantile hemangiomas receiving pulsed dye laser and/or cryosurgery were enrolled as controls. Baseline electrocardiogram, echocardiogram, and chest x-ray were performed. Monitoring of heart rate, blood pressure, and blood glucose was performed every 2 weeks. Efficacy was assessed by performing blinded volume measurements and taking photographs at every visit. Propranolol induced significantly earlier involution and redness reduction of infantile hemangiomas, compared to pulsed dye laser and cryosurgery. Adverse effects such as hypoglycemia, hypotension, or bradycardia did not occur. CONCLUSION: The dramatic response of infantile hemangiomas to propranolol and few side effects suggest that early treatment of infantile hemangiomas could result in decreased disfigurement. Propranolol should be considered as a first-line treatment of infantile hemangiomas.


Assuntos
Antagonistas Adrenérgicos beta/uso terapêutico , Criocirurgia , Hemangioma/tratamento farmacológico , Lasers de Corante/uso terapêutico , Propranolol/uso terapêutico , Neoplasias Cutâneas/tratamento farmacológico , Administração Oral , Esquema de Medicação , Feminino , Hemangioma/cirurgia , Humanos , Lactente , Masculino , Estudos Prospectivos , Neoplasias Cutâneas/cirurgia , Resultado do Tratamento
6.
Pediatr Cardiol ; 34(1): 64-9, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22639007

RESUMO

A review examined six consecutive cases of patients with esophageal atresia (EA) and tracheoesophageal fistula (TEF) who underwent cardiac surgery at the authors' institution between 2001 and 2011 for associated complex congenital heart diseases. All the patients had a normal karyotype and showed EA with distal TEF. In all cases, gastrostomy was the initial surgical intervention. Cardiac surgery was performed concurrently with gastrostomy for one patient who had a total anomalous pulmonary venous connection with pulmonary venous obstruction. For two patients with duct-dependent pulmonary circulation, EA/TEF was corrected in the neonatal period, and an aortopulmonary shunt operation was electively performed after the first month of life. For two patients with duct-dependent systemic circulation, repair of EA/TEF was performed concurrently with gastrostomy, followed by palliative cardiac surgery during the neonatal period. For another patient without duct-dependent circulation, repair of EA/TEF was performed in the neonatal period. No mortality occurred during a median follow-up period of 6.2 years. However, respiratory complications including severe tracheomalacia for two patients, recurrent episodes of respiratory infection for three patients, and severe gastroesophageal reflux for five patients caused considerable long-term morbidity.


Assuntos
Procedimentos Cirúrgicos Cardíacos/métodos , Atresia Esofágica/cirurgia , Gastrostomia/métodos , Cardiopatias Congênitas/cirurgia , Complicações Pós-Operatórias/epidemiologia , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Criança , Pré-Escolar , Atresia Esofágica/complicações , Feminino , Seguimentos , Gastrostomia/efeitos adversos , Cardiopatias Congênitas/complicações , Humanos , Lactente , Masculino , Prognóstico , Resultado do Tratamento
7.
J Med Case Rep ; 13(1): 302, 2019 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-31547860

RESUMO

BACKGROUND: Torque teno virus-induced aseptic meningitis has not been documented, although torque teno virus infections still remain under consideration for etiological agents. This study identified a torque teno virus sequence using next generation sequencing and immunoglobulin M response to the torque teno virus antigen, therefore, that would be a comprehensive diagnosis for torque teno virus infection. CASE PRESENTATION: A 2-month-old Japanese boy was brought to our hospital because he was irritable, drowsy, and lethargic. He was admitted based on his test results which indicated the possibility of septic meningitis. He was started on treatment with high-dose antibiotics and steroids. On the third day of hospitalization, he became afebrile with improvement in his general status and was discharged on the sixth day. He had no developmental problems for up to 1 year after discharge. Metagenomic ribonucleic acid-Seq pathogen detection using next generation sequencing of a sample of his cerebrospinal fluid, which was collected at admission, revealed three short reads homologous to those in torque teno virus out of a total of 1,708,516 reads. This finding indicated that our patient was positive compared to the torque teno virus-negative cerebrospinal fluid samples (controls) from 13 other patients. The torque teno virus has been shown to have a whole genome sequence of 2810 nt by polymerase chain reaction. We prepared a recombinant GP2 antigen from torque teno virus and used it to study our patient's anti-torque teno virus immune response. An anti-GP2 serum immunoglobulin M response was detected, providing further supportive evidence of torque teno virus infection. CONCLUSIONS: This case speculates that torque teno virus-induced aseptic meningitis has a good course. New technologies like next generation sequencing can help in the identification of such cases, and an accumulation of future cases is expected.


Assuntos
Infecções por Vírus de DNA/diagnóstico , Meningite Asséptica/virologia , Torque teno virus/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Lactente , Masculino , Reação em Cadeia da Polimerase , Torque teno virus/isolamento & purificação , Sequenciamento Completo do Genoma
8.
J Dermatol ; 45(10): 1199-1202, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30051930

RESUMO

Infantile hemangiomas grow rapidly during infancy followed by gradual involution. After involution, residual lesions sometimes remain. Despite the prognosis for eventual involution, infantile hemangiomas often cause great psychosocial morbidity that affects patients and their parents. Oral propranolol usually induces earlier involution and redness reduction in infantile hemangiomas in the proliferative phase. However, to evaluate the effectiveness of oral propranolol for infantile hemangiomas beyond the proliferative phase is difficult because of spontaneous regression. We report five Japanese patients treated with 2 mg/kg per day of oral propranolol for infantile hemangiomas beyond the proliferative phase and compared with three untreated patients. After the oral propranolol treatment for 25 weeks, all the treated patients exhibited earlier color fading than untreated patients. Four patients reached nearly complete resolution. Adverse events occurred in three patients: cold, exanthema subitum and suspected of bronchial asthma, respectively. The propranolol treatment for the patient with suspected of bronchial asthma was suspended for 4 months. Recurrence after termination of treatment was not seen. Oral propranolol (2 mg/kg per day) is a safe and effective treatment for Japanese patients with infantile hemangiomas beyond the proliferative phase.


Assuntos
Hemangioma/tratamento farmacológico , Propranolol/uso terapêutico , Neoplasias Cutâneas/tratamento farmacológico , Administração Oral , Asma/induzido quimicamente , Exantema Súbito/induzido quimicamente , Feminino , Hemangioma/diagnóstico por imagem , Humanos , Lactente , Masculino , Fotografação , Neoplasias Cutâneas/diagnóstico por imagem , Fatores de Tempo , Resultado do Tratamento
9.
J Dermatol ; 45(6): 719-722, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29603774

RESUMO

Infantile hemangiomas undergo rapid growth during early infancy followed by gradual involution. Infantile hemangiomas sometimes impair vital functions or cause disfigurement. Thirty-two Japanese patients between the ages of 1 and 4 months with proliferating infantile hemangiomas received oral propranolol on an outpatient basis. The success rate (complete or nearly complete resolution) at week 25 was 56% (18/32). Two patients dropped out because of a personal reason and moving out. Recurrence after termination of treatment was seen in six patients. Adverse events occurred in 16 patients. There were no adverse events on day 1 (initiation of treatment at a dose of 1 mg/kg per day) and day 8 (dose increase to 2 mg/kg per day). One patient was hospitalized due to pneumonia, and suspended propranolol for 26 days. Oral propranolol at 2 mg/kg per day is effective and safe in Japanese patients with infantile hemangiomas.


Assuntos
Antagonistas Adrenérgicos beta/uso terapêutico , Hemangioma/tratamento farmacológico , Recidiva Local de Neoplasia/epidemiologia , Propranolol/uso terapêutico , Neoplasias Cutâneas/tratamento farmacológico , Administração Oral , Imagem Corporal , Feminino , Seguimentos , Hemangioma/complicações , Humanos , Lactente , Japão/epidemiologia , Masculino , Neoplasias Cutâneas/complicações , Resultado do Tratamento
10.
J Dermatol ; 45(9): 1109-1112, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29952019

RESUMO

Infantile hemangiomas are the most common tumor of childhood and undergo rapid growth during early infancy followed by gradual involution. After involution, residual lesions sometimes remain. Oral propranolol usually induces earlier involution and redness reduction of infantile hemangiomas. However, the optimal treatment duration is unknown and infantile hemangiomas sometimes recur after cessation of treatment. We report three Japanese patients with recurrent infantile hemangiomas on their cheek. These patients were a 1-month-old female baby with a superficial infantile hemangioma, a 3-month-old female baby with a mixed infantile hemangioma and a 4-month-old male baby with a mixed infantile hemangioma. Two of them also received pulsed dye laser treatment. They did not reach complete or nearly complete resolution of infantile hemangiomas at week 25. These patients experienced regrowth of their infantile hemangioma after 20 months of age and took propranolol after the age of 24 months. There were no severe adverse effects. Propranolol may not only be therapeutic but also prophylactic. Patients with infantile hemangiomas who have taken oral propranolol should be followed up at least 6 months after cessation of treatment, especially infantile hemangiomas on the cheek, and those with partial response to propranolol may require close attention in prolonged growth.


Assuntos
Antagonistas Adrenérgicos beta/uso terapêutico , Hemangioma/terapia , Lasers de Corante/uso terapêutico , Recidiva Local de Neoplasia/tratamento farmacológico , Propranolol/uso terapêutico , Neoplasias Cutâneas/terapia , Administração Oral , Feminino , Hemangioma/patologia , Humanos , Lactente , Masculino , Recidiva Local de Neoplasia/patologia , Neoplasias Cutâneas/patologia , Resultado do Tratamento
11.
Clin Pediatr Endocrinol ; 27(3): 171-178, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30083034

RESUMO

This case report describes a male neonate with Graves' disease. The mother's pregnancy was complicated by poorly controlled Graves' disease. The neonate was diagnosed with thyroxine (T3)-predominant Graves' disease with low free triiodothyronine (T4) and high free T3 during antithyroid drug therapy. The patient also presented with persistent pulmonary hypertension of the newborn due to hyperthyroidism and airway stenosis caused by goiter. It was difficult to control thyroid function and maintain free T4 levels with inorganic iodine, thiamazole, and levothyroxine sodium hydrate. We successfully controlled thyroid function using the previous treatments in combination with propylthiouracil. Propylthiouracil suppresses type 1 iodothyronine deiodinase, and its pharmacological action suppresses the conversion of T4 to T3. Therefore, we used propylthiouracil at an earlier stage of intervention in this case. We ceased administration of antithyroid drugs on day 85 of life. Subsequently, as the TRH loading test revealed central hypothyroidism, oral administration of levothyroxine sodium hydrate was continued. Its administration was discontinued at the age of 1 yr. Thyroid-stimulating hormone recovered to normal values, and his development had progressed without complications by the age of 2 yr.

12.
Circ Res ; 96(2): 234-43, 2005 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-15591228

RESUMO

Calcitonin gene-related peptide (CGRP) is a nonadrenergic/noncholinergic (NANC) peptide with vasodilatative/inotropic action that may benefit the failing heart. However, precise mechanisms for its in vivo inotropic action remain unclear. To assess this, dogs with normal or failing (sustained tachypacing) hearts were instrumented for pressure-dimension analysis. In control hearts, CGRP (20 pmol/kg per minute) enhanced cardiac contractility (eg, +33+/-4.2% in end-systolic elastance) and lowered afterload (-14.2+/-2% in systemic resistance, both P<0.001). The inotropic response was markedly blunted by heart failure (+6.5+/-2%; P<0.001 versus control), whereas arterial dilation remained unaltered (-19.3+/-5%). CGRP-positive inotropy was not attributable to reflex activation because similar changes were observed in the presence of a ganglionic blocker. However, it was fully prevented by the beta-receptor antagonist (timolol), identifying a dominant role of sympatho-stimulatory signaling. In control hearts, myocardial interstitial norepinephrine assessed by microdialysis almost doubled in response to CGRP infusion, whereas systemic plasma levels were unchanged. In addition, CGRP receptors were not observed in ventricular myocardium but were prominent in coronary arteries and the stellate ganglia. Ventricular myocytes isolated from normal and failing hearts displayed no inotropic response to CGRP, further supporting indirect sympatho-stimulation as the primary in vivo mechanism. In contrast, the peripheral vasodilatative capacity of CGRP was similar in femoral vascular rings from normal and failing hearts in dogs. Thus, CGRP-mediated positive inotropy is load-independent but indirect and attributable to myocardial sympathetic activation rather than receptor-coupled stimulation in canine hearts. This mechanism is suppressed in heart failure, so that afterload reduction accounts for CGRP-enhanced function in this setting.


Assuntos
Peptídeo Relacionado com Gene de Calcitonina/farmacologia , Cardiotônicos/farmacologia , Fragmentos de Peptídeos/farmacologia , Receptores Adrenérgicos beta/fisiologia , Transdução de Sinais/fisiologia , Agonistas Adrenérgicos beta/farmacologia , Antagonistas Adrenérgicos beta/farmacologia , Animais , Estimulação Cardíaca Artificial , Cães , Líquido Extracelular/química , Artéria Femoral/efeitos dos fármacos , Artéria Femoral/fisiologia , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/fisiopatologia , Hemodinâmica/efeitos dos fármacos , Humanos , Isoproterenol/farmacologia , Masculino , Contração Miocárdica/efeitos dos fármacos , Contração Miocárdica/fisiologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/fisiologia , Norepinefrina/análise , Norepinefrina/sangue , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/efeitos dos fármacos , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/fisiologia , Transdução de Sinais/efeitos dos fármacos , Sistema Nervoso Simpático/fisiologia , Taquicardia/complicações , Timolol/farmacologia , Vasodilatação/efeitos dos fármacos , Vasodilatação/fisiologia
14.
Free Radic Biol Med ; 41(10): 1606-18, 2006 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-17045928

RESUMO

Generation of peroxynitrite (ONOO-) as a result of altered redox balance has been shown to affect cardiac function; however, inconsistencies in the data exist, particularly for myocardial contractility. The hypothesis that the cardiac impact of ONOO- formation depends on its site of generation, intravascular or intramyocardial, was examined. Cardiac contractility was assessed by pressure-volume analysis to delineate vascular versus cardiac changes on direct infusion of ONOO- into the right atria of conscious dogs both with normal cardiac function and in heart failure. Additionally, ONOO- was administered to isolated murine cardiomyocytes to mimic in situ cardiac generation. When infused in vivo, ONOO- had little impact on inotropy but led to systemic arterial dilation, likely as a result of rapid decomposition to NO2- and NO3-. In contrast, infused ONOO- was long lived enough to abolish beta-adrenergic (dobutamine)-stimulated contractility/relaxation, most likely through catecholamine oxidation to aminochrome. When administered to isolated murine cardiomyocytes, ONOO- induced a rapid reduction in sarcomere shortening and whole cell calcium transients, although neither decomposed ONOO- or NaNO2 had any effect. Thus, systemic generation of ONOO- is unlikely to have primary cardiac effects, but may modulate cardiac contractile reserve, via blunted beta-adrenergic stimulation, and vascular tone, as a result of generation of NO2- and NO3-. However, myocyte generation of ONOO- may impair contractile function by directly altering Ca2+ handling. These data demonstrate that the site of generation within the cardiovascular system largely dictates the ability of ONOO- to directly or indirectly modulate cardiac pump function.


Assuntos
Coração/efeitos dos fármacos , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Ácido Peroxinitroso/metabolismo , Ácido Peroxinitroso/farmacologia , Agonistas Adrenérgicos beta/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Cálcio/metabolismo , Diástole/efeitos dos fármacos , Dobutamina/antagonistas & inibidores , Dobutamina/farmacologia , Cães , Técnicas In Vitro , Camundongos , Camundongos Endogâmicos C57BL , Miócitos Cardíacos/metabolismo , Volume Sistólico/efeitos dos fármacos
15.
J Med Chem ; 48(26): 8220-8, 2005 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-16366603

RESUMO

Diazeniumdiolates, more commonly referred to as NONOates, have been extremely useful in the investigation of the biological effects of nitric oxide (NO) and related nitrogen oxides. The NONOate Angeli's salt (Na(2)N(2)O(3)) releases nitroxyl (HNO) under physiological conditions and exhibits unique cardiovascular features (i.e., positive inotropy/lusitropy) that may have relevance for pharmacological treatment of heart failure. In the search for new, organic-based compounds that release HNO, we examined isopropylamine NONOate (IPA/NO; Na[(CH(3))(2)CHNH(N(O)NO]), which is an adduct of NO and a primary amine. The chemical and pharmacological properties of IPA/NO were compared to those of Angeli's salt and a NO-producing NONOate, DEA/NO (Na[Et(2)NN(O)NO]), which is a secondary amine adduct. Under physiological conditions IPA/NO exhibited all the markers of HNO production (e.g., reductive nitrosylation, thiol reactivity, positive inotropy). These data suggest that primary amine NONOates may be useful as HNO donors in complement to the existing series of secondary amine NONOates, which are well-characterized NO donors.


Assuntos
Compostos Azo/química , Doadores de Óxido Nítrico/química , Óxidos de Nitrogênio/química , Animais , Peptídeo Relacionado com Gene de Calcitonina/sangue , Sistema Cardiovascular/efeitos dos fármacos , Sobrevivência Celular , Células Cultivadas , Cricetinae , Cricetulus , GMP Cíclico/sangue , Cães , Glutationa/química , Hemodinâmica/efeitos dos fármacos , Hidrazinas/química , Hidrazinas/farmacologia , Dose Letal Mediana , Masculino , Nitritos/química , Nitritos/farmacologia , Óxidos de Nitrogênio/farmacologia , Ácido Úrico/química
16.
Curr Mol Med ; 4(7): 723-40, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15579020

RESUMO

Nitric oxide has emerged as one of the most important and diverse players in physiology. This small diatomic radical stunned researchers because of its existence and unique biological properties in human physiology. Over the last two decades it was found that NO often has fickle behavior in pathophysiological mechanisms. Where benefiting the host in one case yet inducing and augmenting injury in another. This has lead to confusion in is NO good or bad? Much of the answers to this dichotomy lies in the chemistry of NO and its related nitrogen oxide species. To help understand the complex chemistry with perspective to biology, a discussion on the chemical biology of NO is useful. The chemical biology defines the relevant chemical reaction of NO and nitrogen monoxide in the context of the biological conditions. We discuss in this article the chemistry of nitrogen oxide with different types of biological motifs. Reaction of NO with metal complexes and radicals require low concentration, where formation of reactive nitrogen oxide species require considerably higher amounts and generally are isolated to specific microenvironments in vivo. Though many reactive nitrogen oxide species are formed from chemical reactions with NO, there are several which appear to not require NO to be present, HNO and NO(2). These two species have unique physiological effects and represent additional complexity to this biological picture. From this discussion, a picture can be formed concerning the possible chemical dynamics, which can be plausible in different biological mechanisms.


Assuntos
Óxido Nítrico/química , Óxidos de Nitrogênio/química , Espécies Reativas de Nitrogênio/química , Guanilato Ciclase/metabolismo , Humanos , Metais/química , Óxido Nítrico Sintase/metabolismo , Oxirredução , Estresse Oxidativo , Espécies Reativas de Oxigênio/química
18.
Science ; 331(6023): 1439-43, 2011 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-21415352

RESUMO

Decreased cardiac contractility is a central feature of systolic heart failure. Existing drugs increase cardiac contractility indirectly through signaling cascades but are limited by their mechanism-related adverse effects. To avoid these limitations, we previously developed omecamtiv mecarbil, a small-molecule, direct activator of cardiac myosin. Here, we show that it binds to the myosin catalytic domain and operates by an allosteric mechanism to increase the transition rate of myosin into the strongly actin-bound force-generating state. Paradoxically, it inhibits adenosine 5'-triphosphate turnover in the absence of actin, which suggests that it stabilizes an actin-bound conformation of myosin. In animal models, omecamtiv mecarbil increases cardiac function by increasing the duration of ejection without changing the rates of contraction. Cardiac myosin activation may provide a new therapeutic approach for systolic heart failure.


Assuntos
Miosinas Cardíacas/metabolismo , Insuficiência Cardíaca Sistólica/tratamento farmacológico , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Ureia/análogos & derivados , Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Agonistas Adrenérgicos beta/farmacologia , Regulação Alostérica , Animais , Sítios de Ligação , Cálcio/metabolismo , Miosinas Cardíacas/química , Débito Cardíaco/efeitos dos fármacos , Cães , Feminino , Insuficiência Cardíaca Sistólica/fisiopatologia , Isoproterenol/farmacologia , Masculino , Miócitos Cardíacos/fisiologia , Fosfatos/metabolismo , Ligação Proteica , Conformação Proteica , Isoformas de Proteínas/química , Isoformas de Proteínas/metabolismo , Ratos , Ratos Sprague-Dawley , Ureia/química , Ureia/metabolismo , Ureia/farmacologia , Função Ventricular Esquerda/efeitos dos fármacos
19.
J Physiol ; 580(Pt.3): 951-60, 2007 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-17331988

RESUMO

Donors of nitroxyl (HNO), the reduced congener of nitric oxide (NO), exert positive cardiac inotropy/lusitropy in vivo and in vitro, due in part to their enhancement of Ca(2+) cycling into and out of the sarcoplasmic reticulum. Here we tested whether the cardiac action of HNO further involves changes in myofilament-calcium interaction. Intact rat trabeculae from the right ventricle were mounted between a force transducer and a motor arm, superfused with Krebs-Henseleit (K-H) solution (pH 7.4, room temperature) and loaded iontophoretically with fura-2 to determine [Ca(2+)](i). Sarcomere length was set at 2.2-2.3 microm. HNO donated by Angeli's salt (AS; Na(2)N(2)O(3)) dose-dependently increased both twitch force and [Ca(2+)](i) transients (from 50 to 1000 microm). Force increased more than [Ca(2+)](i) transients, especially at higher doses (332 +/- 33% versus 221 +/- 27%, P < 0.01 at 1000 microm). AS/HNO (250 microm) increased developed force without changing Ca(2+) transients at any given [Ca(2+)](o) (0.5-2.0 mm). During steady-state activation, AS/HNO (250 microm) increased maximal Ca(2+)-activated force (F(max), 106.8 +/- 4.3 versus 86.7 +/- 4.2 mN mm(-2), n = 7-8, P < 0.01) without affecting Ca(2+) required for 50% activation (Ca(50), 0.44 +/- 0.04 versus 0.52 +/- 0.04 microm, not significant) or the Hill coefficient (4.75 +/- 0.67 versus 5.02 +/- 1.1, not significant). AS/HNO did not alter myofibrillar Mg-ATPase activity, supporting an effect on the myofilaments themselves. The thiol reducing agent dithiothreitol (DTT, 5.0 mm) both prevented and reversed HNO action, confirming AS/HNO redox sensitivity. Lastly, NO (from DEA/NO) did not mimic AS/HNO cardiac effects. Thus, in addition to reported changes in Ca(2+) cycling, HNO also acts as a cardiac Ca(2+) sensitizer, augmenting maximal force without altering actomyosin ATPase activity. This is likely to be due to modulation of myofilament proteins that harbour reactive thiolate groups that are targets of HNO.


Assuntos
Coração/fisiologia , Contração Miocárdica/efeitos dos fármacos , Óxidos de Nitrogênio/farmacologia , Animais , ATPase de Ca(2+) e Mg(2+)/metabolismo , Cálcio/metabolismo , Hidrazinas/farmacologia , Técnicas In Vitro , Membranas Intracelulares/metabolismo , Contração Miocárdica/fisiologia , Miocárdio/enzimologia , Miocárdio/metabolismo , Miofibrilas/enzimologia , Doadores de Óxido Nítrico/farmacologia , Nitritos/farmacologia , Concentração Osmolar , Ratos , Ratos Sprague-Dawley
20.
J Am Chem Soc ; 127(2): 722-31, 2005 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-15643898

RESUMO

The recent determination that Angeli's salt may have clinical application as a nitrogen oxide donor for treatment of cardiovascular diseases such as heart failure has led to renewed interest in the mechanism and products of thermal decomposition of Angeli's salt under physiological conditions. In this report, several mechanisms are evaluated experimentally and by quantum mechanical calculations to determine whether HNO is in fact released from Angeli's salt in neutral, aerobic solution. The mechanism of product autoxidation is also considered.


Assuntos
Nitritos/química , Oxigênio/química , Concentração de Íons de Hidrogênio , Doadores de Óxido Nítrico/química , Doadores de Óxido Nítrico/metabolismo , Nitritos/metabolismo , Oxidantes/química , Oxidantes/metabolismo , Oxirredução , Teoria Quântica , Soluções , Espectrometria de Fluorescência , Termodinâmica
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