Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 58
Filtrar
1.
Orphanet J Rare Dis ; 18(1): 33, 2023 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-36814255

RESUMO

BACKGROUND: Long-term sequelae are frequent and often disabling after epidermal necrolysis (Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN)). However, consensus on the modalities of management of these sequelae is lacking. OBJECTIVES: We conducted an international multicentric DELPHI exercise to establish a multidisciplinary expert consensus to standardize recommendations regarding management of SJS/TEN sequelae. METHODS: Participants were sent a survey via the online tool "Survey Monkey" consisting of 54 statements organized into 8 topics: general recommendations, professionals involved, skin, oral mucosa and teeth, eyes, genital area, mental health, and allergy workup. Participants evaluated the level of appropriateness of each statement on a scale of 1 (extremely inappropriate) to 9 (extremely appropriate). Results were analyzed according to the RAND/UCLA Appropriateness Method. RESULTS: Fifty-two healthcare professionals participated. After the first round, a consensus was obtained for 100% of 54 initially proposed statements (disagreement index < 1). Among them, 50 statements were agreed upon as 'appropriate'; four statements were considered 'uncertain', and ultimately finally discarded. CONCLUSIONS: Our DELPHI-based expert consensus should help guide physicians in conducting a prolonged multidisciplinary follow-up of sequelae in SJS-TEN.


Assuntos
Síndrome de Stevens-Johnson , Humanos , Síndrome de Stevens-Johnson/complicações , Consenso , Pele , Progressão da Doença
3.
Br J Dermatol ; 185(3): 616-626, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33657677

RESUMO

BACKGROUND: Supportive care is the cornerstone of management of adult and paediatric Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). However, consensus on the modalities of supportive care is lacking. OBJECTIVES: Our aim in this international multicentric Delphi exercise was to establish a multidisciplinary expert consensus to standardize recommendations regarding supportive care in the acute phase of SJS/TEN. METHODS: Participants were sent a survey via the online tool SurveyMonkey, consisting of 103 statements organized into 11 topics: multidisciplinary team composition, suspect drug management, infection prevention, fluid resuscitation and prevention of hypothermia, nutritional support, pain and psychological distress management, management of acute respiratory failure, local skincare, ophthalmological management, management of other mucosa, and additional measures. Participants evaluated the level of appropriateness of each statement on a scale of 1 (extremely inappropriate) to 9 (extremely appropriate). The results were analysed according to the RAND/UCLA Appropriateness Method. RESULTS: Forty-five participants from 13 countries (on three continents) participated. After the first round, a consensus was obtained for 82.5% of the 103 initially proposed statements. After the second round, a final consensus was obtained for 102 statements. CONCLUSIONS: We have reached an international Delphi-based consensus on best supportive care practice for SJS/TEN. Our expert consensus should help guide physicians in treating patients with SJS/TEN and thereby improve short-term prognosis and the risk of sequelae.


Assuntos
Síndrome de Stevens-Johnson , Adulto , Criança , Consenso , Humanos , Pesquisa , Estudos Retrospectivos , Síndrome de Stevens-Johnson/diagnóstico , Síndrome de Stevens-Johnson/terapia
8.
Br J Dermatol ; 176(2): 423-430, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28004387

RESUMO

BACKGROUND: Previous studies have shown that skin disease in dermatomyositis (DM) is best assessed using the Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI). Although the CDASI has been validated for use by dermatologists, it has not been validated for use by other physicians such as rheumatologists and neurologists, who also manage patients with DM and assess skin activity in clinical trials. OBJECTIVES: To assess the reliability of the CDASI among dermatologists, rheumatologists and neurologists. METHODS: Fifteen patients with cutaneous DM were assessed using the CDASI and the Physician Global Assessment (PGA) by five dermatologists, five rheumatologists and five neurologists. RESULTS: The mean CDASI activity scores for dermatologists, rheumatologists and neurologists were 21·0, 21·8 and 20·8, respectively. These mean scores were not different among the specialists. The CDASI damage score means for dermatologists, rheumatologists and neurologists were 5·3, 7·0 and 4·8, respectively. The mean scores between dermatologists and rheumatologists were significantly different, but the means between dermatologists and neurologists were not. The intraclass correlation coefficients (ICCs) for interrater reliability for CDASI activity and damage were good to excellent for dermatologists and rheumatologists, and moderate to excellent for neurologists. The ICCs for intrarater reliability for CDASI activity and damage were excellent for dermatologists and rheumatologists and moderate to excellent for neurologists. The PGA displayed lower interrater and intrarater reliability relative to the CDASI. CONCLUSIONS: Our results confirm the reliability of the CDASI when used by dermatologists and rheumatologists. The data for its use by neurologists were not as robust.


Assuntos
Dermatologistas , Dermatomiosite/diagnóstico , Neurologistas , Reumatologistas , Índice de Gravidade de Doença , Análise de Variância , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Reprodutibilidade dos Testes
9.
Transpl Infect Dis ; 17(5): 716-8, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26192234

RESUMO

Cryptococcosis is a fungal infection that typically occurs in severely immunocompromised patients. Here, we report the case of a heart transplant recipient who presented with cutaneous lesions and was diagnosed with disseminated cryptococcosis and then cryptococcal meningitis on the basis of positive Tzanck smear of the lesions, confirmed by culture, highlighting the importance of the skin as a window to systemic disease.


Assuntos
Criptococose/diagnóstico , Dermatomicoses/diagnóstico , Cefaleia/microbiologia , Transplante de Coração , Hospedeiro Imunocomprometido , Complicações Pós-Operatórias/diagnóstico , Criptococose/imunologia , Dermatomicoses/imunologia , Humanos , Masculino , Meningite Criptocócica/diagnóstico , Meningite Criptocócica/imunologia , Pessoa de Meia-Idade , Complicações Pós-Operatórias/imunologia
10.
Cell Transplant ; 21(9): 1945-67, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22513051

RESUMO

Among the animal models of Duchenne muscular dystrophy (DMD), the Golden Retriever muscular dystrophy (GRMD) dog is considered the best model in terms of size and pathological onset of the disease. As in human patients presenting with DMD or Becker muscular dystrophies (BMD), the GRMD is related to a spontaneous X-linked mutation of dystrophin and is characterized by myocardial lesions. In this respect, GRMD is a useful model to explore cardiac pathogenesis and for the development of therapeutic protocols. To investigate whether cardiac progenitor cells (CPCs) isolated from healthy and GRMD dogs may differentiate into myocardial cell types and to test the feasibility of cell therapy for cardiomyopathies in a preclinical model of DMD, CPCs were isolated from cardiac biopsies of healthy and GRMD dogs. Gene profile analysis revealed an active cardiac transcription network in both healthy and GRMD CPCs. However, GRMD CPCs showed impaired self-renewal and cardiac differentiation. Population doubling and telomerase analyses highlighted earlier senescence and proliferation impairment in progenitors isolated from GRMD cardiac biopsies. Immunofluorescence analysis revealed that only wt CPCs showed efficient although not terminal cardiac differentiation, consistent with the upregulation of cardiac-specific proteins and microRNAs. Thus, the pathological condition adversely influences the cardiomyogenic differentiation potential of cardiac progenitors. Using PiggyBac transposon technology we marked CPCs for nuclear dsRed expression, providing a stable nonviral gene marking method for in vivo tracing of CPCs. Xenotransplantation experiments in neonatal immunodeficient mice revealed a valuable contribution of CPCs to cardiomyogenesis with homing differences between wt and dystrophic progenitors. These results suggest that cardiac degeneration in dystrophinopathies may account for the progressive exhaustion of local cardiac progenitors and shed light on cardiac stemness in physiological and pathological conditions. Furthermore, we provide essential information that canine CPCs may be used to alleviate cardiac involvement in a large preclinical model of DMD.


Assuntos
Distrofia Muscular Animal/patologia , Miocárdio/citologia , Miocárdio/patologia , Células-Tronco/patologia , Animais , Diferenciação Celular/fisiologia , Linhagem da Célula , Modelos Animais de Doenças , Cães , Feminino , Citometria de Fluxo , Humanos , Masculino , Camundongos , Camundongos SCID , Distrofia Muscular Animal/genética , Distrofia Muscular Animal/metabolismo , Miocárdio/metabolismo , Ratos , Células-Tronco/metabolismo , Transcriptoma
11.
Med Hypotheses ; 68(5): 1120-5, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17113239

RESUMO

CHF prevalence is continuously increasing worldwide and maintains one of the poorest prognoses of any major disease. Abundant evidence points to derangement of Ca(2+) cycling as the primary biochemical mark of the failing myocyte. Istaroxime is a novel compound with a dual mechanism of action: inhibition of Na(+), K(+)-ATPase and stimulation of SERCA2a. The increase in cytoplasmic Ca(2+) due to Na(+), K(+)-ATPase inhibition together with greater sarcoplasmic reticulum reloading result in both increased inotropy and lusitropy. This effect is seen in normal and failing in vitro and in vivo models. Istaroxime improvement of the contraction-relaxation cycle constitutes a novel therapeutic approach to the treatment of heart failure.


Assuntos
Cardiotônicos/uso terapêutico , Etiocolanolona/análogos & derivados , Insuficiência Cardíaca/tratamento farmacológico , Modelos Cardiovasculares , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Etiocolanolona/uso terapêutico , Humanos , Contração Miocárdica/efeitos dos fármacos , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/genética
12.
J Pharmacol Exp Ther ; 305(2): 765-71, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12606646

RESUMO

(E,Z)-3-((2-Aminoethoxy)imino)androstane-6,17-dione hydrochloride (PST2744) is a novel Na(+)/K(+) pump inhibitor with positive inotropic effects. Compared with digoxin in various experimental models, PST2744 was consistently found to be less arrhythmogenic, thus resulting in a significantly higher therapeutic index. The present work compares the electrophysiological effects of PST2744 and digoxin in guinea pig ventricular myocytes, with the aim to identify a mechanism for their different toxicity. The work showed that 1) the action potential was transiently prolonged and then similarly shortened by both agents; 2) the ratio between Na(+)/K(+) pump inhibition and inotropy was somewhat larger for PST2744 than for digoxin; 3) both agents accelerated inactivation of high-threshold Ca(2+) current (I(CaL)), without affecting its peak amplitude; 4) the transient inward current (I(TI)) induced by a Ca(2+) transient in the presence of complete Na(+)/K(+) pump blockade was inhibited (-43%) by PST2744 but not by digoxin; 5) the conductance of Na(+)/Ca(2+) exchanger current (I(NaCa)), recorded under Na(+)/K(+) pump blockade, was only slightly inhibited by PST2744 (-14%) and unaffected by digoxin; and 6) both agents inhibited delayed rectifier current I(Ks) (

Assuntos
Cardiotônicos/toxicidade , Inibidores Enzimáticos/toxicidade , Etiocolanolona/toxicidade , Cardiopatias/induzido quimicamente , Miocárdio/enzimologia , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Animais , Arritmias Cardíacas/induzido quimicamente , Arritmias Cardíacas/fisiopatologia , Canais de Cálcio/efeitos dos fármacos , Canais de Cálcio/metabolismo , Separação Celular , Digoxina/toxicidade , Relação Dose-Resposta a Droga , Eletrofisiologia , Inibidores Enzimáticos/farmacologia , Etiocolanolona/análogos & derivados , Feminino , Cobaias , Cardiopatias/enzimologia , Técnicas In Vitro , Potenciais da Membrana/efeitos dos fármacos , Canais de Potássio Corretores do Fluxo de Internalização/efeitos dos fármacos
13.
J Pharmacol Exp Ther ; 303(2): 592-600, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12388640

RESUMO

The novel Na(+)/K(+)-ATPase inhibitor (E,Z)-3-((2-aminoethoxy)imino)androstane-6,17-dione hydrochloride (PST2744) was characterized for its inotropic and toxic properties. Inhibition potency on dog kidney Na(+)/K(+)-ATPase was comparable (0.43 microM) to that of digoxin (0.45 microM). PST2744 concentration-dependently increased force of contraction in guinea pig atria and twitch amplitude in isolated guinea pig myocytes; in the latter, aftercontractions developed significantly less than with digoxin. Intravenous infusion of 0.2 mg/kg/min PST2744 in anesthetized guinea pigs exerted an immediate and long-lasting inotropic effect (ED(80) of 1.89 +/- 0.37 mg/kg) without causing lethal arrhythmias up to a cumulative dose of 18 mg/kg. Conversely, an equieffective infusion of digoxin (0.016 mg/kg/min; ED(80) of 0.32 mg/kg) caused lethal arrhythmias at a cumulative dose of 0.81 mg/kg. At a higher rate (0.4 mg/kg/min), PST2744 induced lethal arrhythmias, with a lethal dose/ED(80) ratio significantly greater than digoxin (20.2 +/- 6.3 versus 3.23 +/- 0.55, p < 0.05). Decay of the inotropic effect (t(1/2), min) was significantly faster for PST2744 (6.0 +/- 0.39) than for digoxin (18.3 +/- 4.5, p < 0.05). In anesthetized dogs, PST2744 dose-dependently increased maximum velocity of pressure rise (+dP/dt(max)) in the range 32 to 500 microg/kg i.v. and was safer than digoxin. In conscious dogs with a healed myocardial infarction, PST2744 significantly increased resting values of +dP/dt(max), left ventricular pressure, and SPB, and increased +dP/dt(max) throughout treadmill exercise while reverting the increase in left ventricular end diastolic pressure seen in control animals. Digoxin significantly decreased basal heart rate, while not affecting the hemodynamic response to exercise. Thus, PST2744 represents a new class of Na(+)/K(+)-ATPase inhibitors endowed with inotropic activity comparable with that of digitalis but having greater safety.


Assuntos
Cardiotônicos/farmacologia , Digoxina/farmacologia , Animais , Cardiotônicos/toxicidade , Cães , Relação Dose-Resposta a Droga , Etiocolanolona/análogos & derivados , Etiocolanolona/farmacologia , Cobaias , Átrios do Coração/efeitos dos fármacos , Técnicas In Vitro , Contração Miocárdica/efeitos dos fármacos , Infarto do Miocárdio/fisiopatologia , Miocárdio/citologia , Miocárdio/enzimologia , Esforço Físico/fisiologia , Ensaio Radioligante , ATPase Trocadora de Sódio-Potássio/metabolismo , Função Ventricular Esquerda/efeitos dos fármacos
14.
J Med Chem ; 43(12): 2332-49, 2000 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-10882359

RESUMO

A series of digitalis-like compounds with a 17-aminoalkoxyiminoalkyl or -alkenyl substituent was synthesized and evaluated for inhibition of Na(+),K(+)-ATPase and for inotropic activity. The highest inhibition was found with compounds having the substituent in configuration 17beta and the amino group at a distance of 6 or 7 bonds from C(17) of the digitoxigenin skeleton. The presence of the oxime function strengthens the interaction with the receptor, more if alpha,beta-unsaturated, thus mimicking the electronic situation of the unsaturated lactone in natural digitalis compounds. The most active compounds showed Na(+),K(+)-ATPase inhibitory potencies (IC(50)) 17-25 times higher than the standards digitoxigenin and digoxin and 3-11 times higher inotropic potencies (EC(50)) in isolated guinea pig left atria. These features are supported by a molecular model suggesting the possible interactions of the groups described above with particular amino acid residues in the H1-H2 domains of Na(+),K(+)-ATPase. Some interactions are the classical ones already described in the literature; a new, very strong interaction of the basic group with the Cys138 was found and adds new possibilities to design compounds interacting with this region of the receptor. The most interesting compounds were also studied in vivo in the anesthetized guinea pig for evaluating their inotropic effect versus the lethal dose. Compounds 9 and 12 showed a slightly higher safety ratio than digoxin and deserve further evaluation.


Assuntos
Androstanos/síntese química , Androstanóis/síntese química , Cardiotônicos/síntese química , Glicosídeos Digitálicos/farmacologia , Inibidores Enzimáticos/síntese química , Oximas/síntese química , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , ATPase Trocadora de Sódio-Potássio/química , Androstanos/química , Androstanos/farmacologia , Androstanóis/química , Androstanóis/farmacologia , Animais , Sítios de Ligação , Cardiotônicos/química , Cardiotônicos/farmacologia , Cães , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Cobaias , Átrios do Coração/efeitos dos fármacos , Técnicas In Vitro , Rim/enzimologia , Masculino , Modelos Moleculares , Contração Miocárdica/efeitos dos fármacos , Ouabaína/química , Ouabaína/metabolismo , Oximas/química , Oximas/farmacologia , ATPase Trocadora de Sódio-Potássio/metabolismo , Relação Estrutura-Atividade
15.
J Cardiovasc Pharmacol ; 27(1): 52-7, 1996 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8656658

RESUMO

Propionyl-L-carnitine (PLC) was shown to improve global cardiac function in pressure overload hypertrophy by acting directly on muscle mechanics. We investigated whether PLC can effectively ameliorate papillary muscle mechanics in a volume overload (VO) model. We induced VO by constructing an aortocaval anastomosis in adult Wistar rats. Three experimental groups were studied: sham-operated controls and untreated and PLC-treated VO animals. Isometric function of right and left papillary muscle was studied 16-18 weeks later. PLC was administered in the drinking water at the dose of 180 mg/kg for the last 2 weeks before experiment. One-way analysis of variance (ANOVA) showed that in right papillary muscles from the untreated VO group the time course of the isometric contraction was significantly prolonged [time-to-peak tension (TPT, ms +/- SEM) from 126 +/- 4.9 to 156 +/- 7.1; time from peak tension to 30% relaxation (TRel) from 133 +/- 11.9 to 196 +/- 13.9; n = 11 and 8, respectively], and peak rates of contraction and relaxation normalized over developed tension were significantly decreased in comparison with sham [from (s-1 +/- SEM) 12.9 +/- 0.5 to 10.8 +/- 0.6, and from 7.2 +/- 0.6 to 5.2 +/- 0.4, respectively]. These parameters in the PLC VO group did not differ from sham (TPT, 140 +/- 5.7; TRel, 158 +/- 14.4; +dF/df/DT, 12.2 +/- 0.6; -dF/df/DT, 6.5 +/- 0.5; n = 8). Function of left papillary muscle was not modified by either VO or PLC treatment. Total carnitine levels in either ventricle free walls were unchanged by VO. PLC significantly increased total carnitine content of left ventricle free wall (from 5.4 +/- 0.28 to 7.0 +/- 0.50). The contraction changes observed in the right papillary muscle are likely to depend on the pressure overload occurring in the right chamber; moreover, they are unrelated to tissue carnitine depletion. PLC improved the altered right papillary muscle mechanics without exerting any apparent effect on the functionally normal left papillary muscle. PLC activity is independent of carnitine stores, but may presumably be ascribed to its anaplerotic properties.


Assuntos
Cardiotônicos/farmacologia , Carnitina/análogos & derivados , Músculos Papilares/efeitos dos fármacos , Anastomose Cirúrgica , Animais , Aorta Abdominal/cirurgia , Cardiomegalia/patologia , Cardiomegalia/fisiopatologia , Carnitina/farmacologia , Masculino , Músculos Papilares/patologia , Músculos Papilares/fisiopatologia , Ratos , Ratos Wistar , Veias Cavas/cirurgia
16.
Eur J Pharmacol ; 286(2): 147-54, 1995 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-8605951

RESUMO

Chronic administration of propionyl-l-carnitine has been recently shown to correct hypertrophy related abnormalities in muscle mechanics. Accordingly, this study investigated whether the drug would similarly improve cardiac dynamics in rats with pressure overload. Enalapril was used for comparison. Drugs were administered in the drinking water for 3 weeks to Wistar Kyoto rats with a 2 week abdominal aortic constriction. Cardiac function was studied under urethane anaesthesia in basal conditions, during increase in preload, and during increase in afterload. Basal cardiac function was comparable in pressure-overloaded and sham-operated animals. Neither propionyl-l-carnitine nor enalapril affected the basal performance. Compared to sham-operated animals, untreated pressure-overloaded rats showed an impaired cardiac response (cardiac output, stroke volume) to preload increase induced by saline i.v. infusion. Propionyl-l-carnitine dose dependently improved cardiac function in the range 30-180 mg/kg, without affecting cardiac hypertrophic growth. Enalapril (3 mg/kg) reduced cardiac hypertrophy and improved cardiac function. The two effects were unrelated. The afterload increase by total aortic occlusion evidenced a reduction in the left ventricle pressure generating capacity of hypertrophied hearts. Propionyl-l-carnitine did not modify this parameter, while enalapril afforded a significant improvement. Results show that propionyl-l-carnitine significantly improves in vivo cardiac dynamics under conditions of increased energy demand. The effect is not due to inotropic efficacy, but presumably to increased cardiac efficiency.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Cardiotônicos/farmacologia , Carnitina/análogos & derivados , Enalapril/farmacologia , Coração/efeitos dos fármacos , Animais , Carnitina/farmacologia , Hemodinâmica/efeitos dos fármacos , Masculino , Ratos , Ratos Endogâmicos WKY
17.
Am J Physiol ; 268(4 Pt 2): H1702-13, 1995 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-7733374

RESUMO

To determine whether alterations in the mechanical properties and calcium transients of myocytes are important factors in the evolution of the postinfarcted heart, these physiological parameters were measured in the viable muscle cells of the left ventricle 6 h, 2-3 days, 1 wk, and 1 mo after coronary artery occlusion and the documentation of left ventricular failure. In addition, the effects of propionyl-L-carnitine (PLC) on shortening properties and calcium dynamics of single myocytes were established to demonstrate whether the potential increase in ATP generation by this intervention improved myocyte cell function. Myocardial infarction was associated with a progressive increase in length of the spared myocytes, whereas the changes in myocyte diameter were apparent only at the 1-mo interval. Mechanically, myocyte shortening was decreased 43% at 6 h, 34% at 2-3 days, 26% at 1 wk, and 41% at 1 mo after infarction. Similar abnormalities were noted in the velocity of myocyte shortening. Peak systolic calcium was decreased at all intervals after infarction. In contrast, diastolic calcium remained within control values. PLC was capable of ameliorating the mechanical behavior and calcium transients of myocytes, particularly 1 mo after infarction. Thus alterations in muscle cell performance may be important determinants in the development and progression of ischemic cardiomyopathy, and interventions improving myocyte contractility may interfere with the unfavorable outcome of the disease.


Assuntos
Carnitina/análogos & derivados , Coração/fisiopatologia , Infarto do Miocárdio/patologia , Infarto do Miocárdio/fisiopatologia , Animais , Cálcio/metabolismo , Cardiotônicos/farmacologia , Carnitina/farmacologia , Citosol/metabolismo , Estimulação Elétrica , Coração/efeitos dos fármacos , Masculino , Miocárdio/patologia , Ratos , Ratos Sprague-Dawley
19.
Am J Physiol ; 266(6 Pt 2): H2190-7, 1994 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8023981

RESUMO

This study investigated if propionyl-L-carnitine (PLC) treatment can directly affect cardiac mechanics, secondary to increase in myocardial carnitine content, in rats with aortic constriction and sham-operated controls. After weaning, rats were fed one of the following diets for 8 wk: 1) a low-carnitine diet (containing 2 nmol/g carnitine); 2) the same diet supplemented with PLC (710 mumol/kg body wt); 3) L-carnitine (LC; 118 mumol/kg body wt, given in tap water; or 4) a standard diet (containing 56 nmol/g carnitine). A 4-wk constriction of the abdominal aorta caused left ventricular hypertrophy associated with significantly prolonged timing parameters and reduced rate of tension decay in papillary muscles. In group 2, however, PLC treatment prevented hypertrophy-induced changes in these parameters and the reduction in unloaded shortening velocity in skinned trabeculae. Finally, PLC treatment maintained the relative proportion of myosin heavy chain isoforms in left ventricular wall of animals subjected to aortic constriction. Both PLC and LC completely prevented carnitine depletion due to hypertrophy and to dietary restriction. Because LC did not modify papillary muscle contractile function, these results demonstrate that PLC affects hypertrophy-induced changes in muscle mechanics and ventricular wall composition independently of tissue carnitine levels.


Assuntos
Carnitina/análogos & derivados , Coração/efeitos dos fármacos , Coração/fisiopatologia , Hipertensão/fisiopatologia , Animais , Aorta , Cardiomegalia/etiologia , Cardiotônicos/farmacologia , Carnitina/metabolismo , Carnitina/farmacologia , Constrição Patológica , Ventrículos do Coração , Masculino , Contração Miocárdica , Miocárdio/metabolismo , Miosinas/metabolismo , Músculos Papilares/fisiopatologia , Ratos , Ratos Endogâmicos WKY
20.
Mol Cell Biochem ; 125(2): 179-92, 1993 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-8283973

RESUMO

Ventricular cardiomyocytes represent the most important source of atrial natriuretic factor (ANF) in pathological conditions such as congestive heart failure (CHF). It has been suggested that in cardiomyopathic Syrian hamster ventricles the ANF gene can be reactivated during the hypertrophic stage occurring before heart failure. The present study was undertaken to investigate ANF gene expression during early stages of myocardial damage and its distribution throughout atrial and ventricular myocardium in UM-X7.1 cardiomyopathic Syrian hamsters (CMPH) before hypertrophy and cardiac failure occur. Atria, right and left ventricles, and interventricular septum of hearts of 20-23 days old (young) and 90-95 days old (adult) CMPH were studied. The absence of hypertrophy and cardiac failure was preliminarly ascertained by microscopic and hemodynamic evaluation. ANF-mRNA as well as tissue and plasma immunoreactive ANF were assayed. Moreover, ANF secretion pattern was evaluated by immunocytochemical techniques. Young and adult CMPH hearts were in the necrotic stage of myocardial disease, as demonstrated by histopathological evaluation and by decreased wet weights (mg/g body weight) of different heart regions. Hemodynamic assessment showed no significant changes of left ventricular end-diastolic pressure (LVEDP) and a decrease of the left ventricular peak systolic pressure (LVSP) and +dP/dt. Plasma immunoreactive ANF (IR-ANF) levels were higher in young (3-fold) and adult (6-fold) CMPH than in age-matched normal hamsters. A reduced IR-ANF concentration (per milligram protein) was observed in both young and adult cardiomyopathic atria in respect to healthy controls, whereas a higher IR-ANF concentration was present in ventricles. A 3-fold, 6-fold and 20-fold increase of IR-ANF concentration was found in right ventricular free-wall (RV), left ventricular free-wall (LV) and interventricular septum (IVS), respectively. Northern-blot analysis confirmed that IVS was the major site of ventricular ANF-mRNA transcription in both young and adult CMPH. ANF-mRNA was increased also in atria where a faster peptide secretion can be hypothesized to lower tissue IR-ANF concentration. ANF secretion in ventricular myocardium was achieved via constitutive pathway as demonstrated by immunocytochemistry. Different patterns of ANF gene reactivation occur in CMPH myocardium before intraventricular pressure increases and structural hypertrophic modifications are detectable. The extent of ANF gene reactivation in CMPH ventricles parallels the severity of necrotic damage. Moreover, ANF gene expression is heterogeneously distributed throughout the myocardium, suggesting that interventricular septum, the ontogenically youngest heart region, might preserve foetal characters which can be rapidly reactivated in pathological conditions.


Assuntos
Fator Natriurético Atrial/genética , Cardiomiopatias/metabolismo , Miocárdio/metabolismo , Animais , Fator Natriurético Atrial/análise , Cardiomiopatias/patologia , Cricetinae , Expressão Gênica , Ventrículos do Coração/química , Hemodinâmica/fisiologia , Imuno-Histoquímica , Mesocricetus , RNA Mensageiro/análise , Distribuição Aleatória , Valores de Referência , Fatores de Tempo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA