Caffeine Stimulates in vivo Overall Cell Metabolism

ABSTRACT The influence of caffeine on overall cell metabolism was studied in human platelets by measurement of cell heat production rate. One hour after administration of 100-200 mg of caffeine, corresponding to 1-2 cups of coffee, significantly increased values (p<0.001) were found, 12±7%. A return to normal values was noted 1 hour later. The cell metabolic stimulation is presumably due to increased catecholamines. A temporary significant rise in systolic (p<0.02) and diastolic (p<0.05) blood pressure was observed 1 hour after ingestion of caffeine.     

The Sleep Disturbance Scale for Children (SDSC) Construct ion and validation of an instrument to evaluate sleep disturbances in childhood and adolescence

SUMMARY To attempt a categorization of sleep disorders in children, we developed a 27 item Likert-type rating scale (Sleep Disturbance Scale for Children: SDSC) and assessed the psychometric properties was developed. The scale was distributed to the mothers of 1304 children (1157 controls, mean age 9.8y; 147 sleep disorder subjects, mean age 9.2y, composed of four clinical groups: Insomnia 39 subjects, Hypersomnia 12 subjects, Respiratory disturbances during sleep 25 subjects and Parasomnias 71 subjects). The internal consistency was high in controls (0.79) and remained at a satisfactory level in sleep disorder subjects (0.71); the test/retest reliability was adequate for the total (r = 0.71) and single item scores. The factor analysis (variance explained 44.21%) yielded six factors which represented the most common areas of sleep disorders in childhood and adolescence. Enuresis was the only item with a factor loading lower than 0.40 and with a low inter-item correlation and was therefore eliminated, resulting in a final scale of 26 items. The re-evaluation of the sample, using the factor scores, supported the validity and the discriminating capacity of the scales between controls and the four clinical groups. The correlation between factor scores corroborated the hypothesis that childhood sleep disturbances are not independent entities nor do they cluster into different groupings related to each other. The SDSC appears to be a useful tool in evaluating the sleep disturbances of school-age children in clinical and non-clinical populations.     

The release of β- thromboglobulin and platelet factor 4 during extracorporeal circulation for open heart surgery

Cardiopulmonary bypass is extremely damaging to platelets and it causes a quantitative and qualitative alteration in their functions. We evaluated the release of two platelet-specific proteins, beta-thromboglobulin (beta TG) and platelet factor 4 (PF4), in patients who underwent extracorporeal circulation for open heart surgery. A parallel release (basal value beta TG: 119.6 ng/ml, PF4 30 ng/ml) was present for both proteins in a time dependent fashion until the end of extracorporeal circulation. High average levels were observed in patients in whom the bypass was stopped after about 1 h (beta TG 1606 ng/ml, PF4 745 ng/ml) and similarly in those in whom the bypass was stopped after about 2 h (beta TG 1540 ng/ml, PF 4754 ng/ml). No correlation was found either between the level of PF4 and the additional heparin administered after the initial standard dose (r = 0.29, P greater than 0.10) and between the level of PF4 and the amount of heparin consumed during the bypass (r = 0.05, P greater than 0.5).     

Antiarrhythmic Drug Therapy after Radiofrequency Catheter Ablation in Patients with Atrial Fibrillation

Objectives: The use of antiarrhythmic drugs after ablation is a controversial issue when evaluating the efficacy of atrial fibrillation (AF) ablation. This study compares in a prospective and randomized fashion the impact of an antiarrhythmic drug in preventing AF recurrence after AF ablation.
Methods: From February 2004 to May 2005, 107 consecutive patients (mean age 57 ± 10 years, 69 men), with paroxysmal (60%) or persistent (40%) drug refractory AF, were randomly assigned to ablation alone (Group A, 53 patients) or combined with the best antiarrhythmic therapy, preferably amiodarone (Group B, 54 patients). All patients underwent cavo-tricuspid and left inferior pulmonary vein (PV)-mitral isthmus ablation plus circumferential PV ablation, using a guided electro-anatomical approach. Standard electrocardiograms (ECG), and ambulatory and transtelephonic ECG monitoring were used to assess AF recurrences. Recurrences during the first month after ablation were excluded from this analysis.
Results: At 12 months of follow-up, no significant difference was observed in the rates of AF recurrences between Group A (18/53 patients, 34%) and Group B (16/54 patients, 30%). The percentage of patients with ≥1 asymptomatic AF episode was higher in Group B than in Group A (10/16 patients, 63%, vs 5/18 patients, 28%, P = 0.04).
Conclusions: Continuing antiarrhythmic drug therapy in patients who undergo catheter ablation for AF did not lower the rate of AF recurrences. Antiarrhythmic drugs increased the proportion of patients with asymptomatic AF episodes.