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1.
Neurology ; 60(11): 1811-6, 2003 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-12796536

RESUMO

BACKGROUND: Mutations in KCNJ2, the gene encoding the inward-rectifying K+ channel Kir2.1, cause the cardiac, skeletal muscle, and developmental phenotypes of Andersen-Tawil syndrome (ATS; also known as Andersen syndrome). Although pathogenic mechanisms have been proposed for select mutations, a common mechanism has not been identified. METHODS: Seventeen probands presenting with symptoms characteristic of ATS were evaluated clinically and screened for mutations in KCNJ2. The results of mutation analysis were combined with those from previously studied subjects to assess the frequency with which KCNJ2 mutations cause ATS. RESULTS: Mutations in KCNJ2 were discovered in nine probands. These included six novel mutations (D71N, T75R, G146D, R189I, G300D, and R312C) as well as previously reported mutations R67W and R218W. Six probands possessed mutations of residues implicated in binding membrane-associated phosphatidylinositol 4,5-bisphosphate (PIP2). In total, mutations in PIP(2)-related residues accounted for disease in 18 of 29 (62%) reported KCNJ2 -based probands with ATS. Also reported is that mutation R67W causes the full clinical triad in two unrelated males. CONCLUSIONS: The novel mutations corresponding to residues involved in Kir2.1 channel-PIP2 interactions presented here as well as the overall frequency of mutations occurring in these residues indicate that defects in PIP2 binding constitute a major pathogenic mechanism of ATS. Furthermore, screening KCNJ2 in patients with the complex phenotypes of ATS was found to be invaluable in establishing or confirming a disease diagnosis as mutations in this gene can be identified in the majority of patients.


Assuntos
Anormalidades Múltiplas/genética , Arritmias Cardíacas/genética , Mutação , Paralisia/genética , Fosfatidilinositol 4,5-Difosfato/metabolismo , Canais de Potássio Corretores do Fluxo de Internalização/genética , Anormalidades Múltiplas/diagnóstico , Anormalidades Múltiplas/patologia , Arritmias Cardíacas/diagnóstico , Sítios de Ligação , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Debilidade Muscular/genética , Paralisia/diagnóstico , Linhagem , Fenótipo , Canais de Potássio Corretores do Fluxo de Internalização/química , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo , Síndrome
2.
Cardiol Young ; 9(3): 323-6, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10386705

RESUMO

A 3-year-old patient is described with an unusual form of co-arctation due to hypoplasia of the transverse arch and fibromuscular dysplasia involving a long segment of the thoracic aorta. Surgical repair required resection of the aorta from the distal transverse arch to the mid-descending thoracic aorta, and replacement with a 16-mm Dacron interposition graft. This case demonstrates the importance of preoperative evaluation of the entire aorta in the presence of co-arctation due to fibromuscular dysplasia.


Assuntos
Coartação Aórtica/etiologia , Displasia Fibromuscular/complicações , Implante de Prótese Vascular , Pré-Escolar , Feminino , Humanos
3.
J Am Soc Echocardiogr ; 11(10): 948-56, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9804099

RESUMO

Transfusion-dependent (TD) patients develop cardiac iron overload that will eventually lead to cardiac pump failure. Low-dose dobutamine stress echocardiography may complement resting echocardiography and identify preclinical myocardial dysfunction caused by early cardiac hemosiderosis. Twenty-six iron-overloaded TD patients had stress echocardiography with 5 microg/kg per minute of dobutamine. Indexed left ventricular (LV) mass, LV dimensions, meridional wall stress, and cardiac index were significantly increased. TD patients had similar LV shortening fraction by M-mode (40.5% +/- 5.6% vs 39.4% +/- 4.5%) but had a lower mean LV ejection fraction (53.3% +/- 3.9% vs 46.8% +/- 6.9%, P < .002) and a subnormal increase in cardiac index during dobutamine stress (35% +/- 20% vs 11% +/- 16%, P < .0001). Impairment in LV relaxation was demonstrated by a prolonged isovolumetric relaxation time (0.060 +/- 0.005 vs 0.088 +/- 0.019 seconds, P < .0001), increased peak mitral E wave, and abnormal E/A ratio. Asymptomatic TD patients demonstrate decreased systolic functional reserve and abnormal left ventricular relaxation that may be caused by cardiac hemosiderosis. Low-dose dobutamine stress echocardiography may be useful for detecting and following cardiac dysfunction in patients at risk for cardiac hemosiderosis.


Assuntos
Cardiomiopatias/diagnóstico por imagem , Cardiotônicos , Dobutamina , Transfusão de Eritrócitos , Hemossiderose/complicações , Disfunção Ventricular/diagnóstico por imagem , Adolescente , Adulto , Cardiomiopatias/complicações , Criança , Diástole , Teste de Esforço , Feminino , Hemodinâmica , Hemossiderose/etiologia , Humanos , Masculino , Sístole , Ultrassonografia , Disfunção Ventricular/complicações
4.
Pediatrics ; 100(2): E11, 1997 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9233982

RESUMO

OBJECTIVE: Atrial flutter is an uncommon arrhythmia in the pediatric population except for the immediate newborn period or following atrial repair of congenital heart disease. In children the diagnosis of atrial flutter may be difficult, attributable to rapid atrioventricular conduction and superimposition of flutter waves on QRS and T waves. Atrial flutter secondary to hyperthyroidism has been rarely reported in older adults, but there are no reports of children presenting with atrial flutter as the initial manifestation of hyperthyroidism. CASE REPORT: We report an interesting case of hyperthyroidism in a 3-year-old presenting with congestive heart failure and atrial flutter with 1:1 atrioventricular conduction. The responses to adenosine administration and to cardioversion were unusual and ultimately helpful in suggesting the diagnosis of hyperthyroidism. CONCLUSION: When atrial flutter is encountered in a pediatric patient in whom there is 1:1 atrioventricular conduction, a lack of a response to adenosine, and persistent sinus tachycardia after cardioversion, the clinician should be alert to the possibility of thyrotoxicosis.


Assuntos
Flutter Atrial/etiologia , Hipertireoidismo/complicações , Adenosina , Flutter Atrial/diagnóstico , Pré-Escolar , Eletrocardiografia , Insuficiência Cardíaca/etiologia , Humanos , Hipertireoidismo/diagnóstico
6.
Brain Res Bull ; 3(5): 571-4, 1978.
Artigo em Inglês | MEDLINE | ID: mdl-122724

RESUMO

Modification of standard rabbit stereotaxic apparatus to allow adjustment of the tooth bar in the vertical plane may be accomplished by simple machining of a standard laboratory clamp and aluminum rod. The modification greatly increases speed of head positioning for implant surgery. Machining the chrome and brass luer hub of standard stainless steel hypodermic needles to the described configurations produces improved guide tubes for brain temperature recording and cannulae for brain microinjections. Data from hypothalamic injection of prostaglandin E1 and records of resulting changes in brain temperature support the effectiveness of the methods described.


Assuntos
Microinjeções/instrumentação , Técnicas Estereotáxicas/instrumentação , Termografia/instrumentação , Animais , Coelhos
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