RESUMEN
Single fast spin echo scans covering limited time frames are mostly used for contrast-enhanced MRI of atherosclerotic plaque biomarkers. Knowledge on inter-scan variability of the normalized enhancement ratio of plaque (NER(plaque)) and relation between NER(plaque) and gadolinium content for inversion-recovery fast spin echo is limited. Study aims were: evaluation of (1) timing of MRI after intravenous injection of cannabinoid-2 receptor (CB2-R) (expressed by human and mouse plaque macrophages) targeted micelles; (2) inter-scan variability of inversion-recovery fast spin echo and fast spin echo; (3) relation between NER(plaque) and gadolinium content for inversion-recovery fast spin echo and fast spin echo. Inversion-recovery fast spin echo/fast spin echo imaging was performed before and every 15 min up to 48 h after injection of CB2-R targeted or control micelles using several groups of mice measured in an interleaved fashion. NER(plaque) (determined on inversion-recovery fast spin echo images) remained high (â¼2) until 48 h after injection of CB2-R targeted micelles, whereas NER(plaque) decreased after 36 h in the control group. The inter-scan variability and relation between NER(plaque) and gadolinium (assessed with inductively coupled plasma- mass spectrometry) were compared between inversion-recovery fast spin echo and fast spin echo. Inter-scan variability was higher for inversion-recovery fast spin echo than for fast spin echo. Although gadolinium and NER(plaque) correlated well for both techniques, the NER of plaque was higher for inversion-recovery fast spin echo than for fast spin echo. In mice injected with CB2-R targeted micelles, NER(plaque) can be best evaluated at 36-48 h post-injection. Because NER(plaque) was higher for inversion-recovery fast spin echo than for fast spin echo, but with high inter-scan variability, repeated inversion-recovery fast spin echo imaging and averaging of the obtained NER(plaque) values is recommended.
Asunto(s)
Gadolinio/metabolismo , Aumento de la Imagen/métodos , Imagen por Resonancia Magnética/métodos , Micelas , Placa Aterosclerótica , Receptor Cannabinoide CB2/metabolismo , Animales , Apolipoproteínas E/genética , Biomarcadores/metabolismo , Humanos , Imagen por Resonancia Magnética/instrumentación , Ratones , Ratones Noqueados , Óxido Nítrico Sintasa de Tipo III/genética , Placa Aterosclerótica/metabolismo , Placa Aterosclerótica/patología , Factores de Tiempo , Distribución TisularRESUMEN
To determine the effect of training on insulin sensitivity (IS) and how this relates to peak V(.)O(2) (peak oxygen uptake) in CHF (chronic heart failure), 77 CHF patients (New York Heart Association class, II/III; men/women, 59/18; age, 60+/-9 years; body mass index, 26.7+/-3.9 kg/m(2); left ventricular ejection fraction, 26.9+/-8.1%; expressed as means+/-S.D.) participated in the study. Patients were randomly assigned to a training or control group (TrG or CG respectively). Sixty-one patients completed the study. Patients participated in training (combined strength and endurance exercises) four times per week, two times supervised and two times at home. Before and after intervention, anthropometry, IS (euglycaemic hyperinsulinaemic clamp) and peak V(.)O(2) (incremental cycle ergometry) were assessed. Intervention did not affect IS significantly, even though IS increased by 20% in TrG and 11% in CG (not significant). Peak V(.)O(2) increased as a result of training (6% increase in TrG; 2% decrease in CG; P <0.05). In both groups (TrG and CG), the change in IS correlated positively with the change in peak V(.)O(2) ( r =0.30, P <0.05). Training resulted in an increase in peak V(.)O(2), but not in IS. Whether physical training actually increases IS in CHF patients remains unclear.
Asunto(s)
Terapia por Ejercicio , Insuficiencia Cardíaca/rehabilitación , Insulina/fisiología , Anciano , Composición Corporal , Tolerancia al Ejercicio , Femenino , Técnica de Clampeo de la Glucosa , Insuficiencia Cardíaca/tratamiento farmacológico , Insuficiencia Cardíaca/fisiopatología , Humanos , Resistencia a la Insulina , Masculino , Persona de Mediana Edad , Consumo de OxígenoRESUMEN
Patients with an idiopathic increase in serum creatine kinase (CK) levels (hyper-CK-emia) have a benign prognosis, but symptoms may be disabling in daily life. Previous studies have suggested that physical exercise increases the severity of complaints in these patients. We studied whether maximal and submaximal bouts of exercise on a cycle ergometer are harmful for patients with idiopathic hyper-CK-emia. Such dynamic exercise did not lead to larger increases in serum CK activity or more complaints in 11 patients with idiopathic hyper-CK-emia, compared with 11 age-matched healthy controls. Our data suggest that exercise does not result in more extensive muscle damage in patients with idiopathic hyper-CK-emia than in healthy subjects.