Diagnostic score for heparin-induced thrombocytopenia after cardiopulmonary bypass.

Heparin-induced thrombocytopenia (HIT) occurs in nearly 3% of patients treated with heparin after cardiopulmonary bypass (CPB). HIT carries a risk of severe thrombotic complications, and must be diagnosed rapidly. To identify simple criteria for estimating the probability of HIT after CPB, we retrospectively analyzed the files of 84 patients with suspected HIT after CPB and we analyzed the usefulness of several variables collected at the time of HIT suspicion to estimate HIT probability. HIT was confirmed in 35 cases and ruled out in 49 cases, on the basis of a platelet increment after heparin withdrawal, detection of heparin-dependent antibodies, and absence of other clear cause of thrombocytopenia. A biphasic platelet count from CPB to the first day of suspected HIT, an interval of >/= 5 days from CPB to the first day of suspected HIT, and a CPB duration of

Homo-FRET microscopy in living cells to measure monomer-dimer transition of GFP-tagged proteins.

Fluorescence anisotropy decay microscopy was used to determine, in individual living cells, the spatial monomer-dimer distribution of proteins, as exemplified by herpes simplex virus thymidine kinase (TK) fused to green fluorescent protein (GFP). Accordingly, the fluorescence anisotropy dynamics of two fusion proteins (TK27GFP and TK366GFP) was recorded in the confocal mode by ultra-sensitive time-correlated single-photon counting. This provided a measurement of the rotational time of these proteins, which, by comparing with GFP, allowed the determination of their oligomeric state in both the cytoplasm and the nucleus. It also revealed energy homo-transfer within aggregates that TK366GFP progressively formed. Using a symmetric dimer model, structural parameters were estimated; the mutual orientation of the transition dipoles of the two GFP chromophores, calculated from the residual anisotropy, was 44.6 +/- 1.6 degrees, and the upper intermolecular limit between the two fluorescent tags, calculated from the energy transfer rate, was 70 A. Acquisition of the fluorescence steady-state intensity, lifetime, and anisotropy decay in the same cells, at different times after transfection, indicated that TK366GFP was initially in a monomeric state and then formed dimers that grew into aggregates. Picosecond time-resolved fluorescence anisotropy microscopy opens a promising avenue for obtaining structural information on proteins in individual living cells, even when expression levels are very low.

Aortic stiffness is an independent predictor of all-cause and cardiovascular mortality in hypertensive patients.

Although various studies reported that pulse pressure, an indirect index of arterial stiffening, was an independent risk factor for mortality, a direct relationship between arterial stiffness and all-cause and cardiovascular mortality remained to be established in patients with essential hypertension. A cohort of 1980 essential hypertensive patients who attended the outpatient hypertension clinic of Broussais Hospital between 1980 and 1996 and who had a measurement of arterial stiffness was studied. At entry, aortic stiffness was assessed from the measurement of carotid-femoral pulse-wave velocity (PWV). A logistic regression model was used to estimate the relative risk of all-cause and cardiovascular deaths. Selection of classic risk factors for adjustment of PWV was based on their influence on mortality in this cohort in univariate analysis. Mean age at entry was 50+/-13 years (mean+/-SD). During an average follow-up of 112+/-53 months, 107 fatal events occurred. Among them, 46 were of cardiovascular origin. PWV was significantly associated with all-cause and cardiovascular mortality in a univariate model of logistic regression analysis (odds ratio for 5 m/s PWV was 2.14 [95% confidence interval, 1.71 to 2.67, P<0.0001] and 2.35 [95% confidence interval, 1.76 to 3.14, P<0.0001], respectively). In multivariate models of logistic regression analysis, PWV was significantly associated with all-cause and cardiovascular mortality, independent of previous cardiovascular diseases, age, and diabetes. By contrast, pulse pressure was not significantly and independently associated to mortality. This study provides the first direct evidence that aortic stiffness is an independent predictor of all-cause and cardiovascular mortality in patients with essential hypertension.

A moderate but not total decrease of mitochondrial membrane potential triggers apoptosis in neuron-like cells.

The effects of various degrees of perturbation of the mitochondrial membrane potential (mt delta psi) on apoptosis was investigated by intensified fluorescence digital-imaging microscopy on neuron-like cells, ND7. Mt delta psi was either decreased by 40% by the protonophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP 100 nM, 15 min) or completely collapsed (FCCP 10 microM, 60 min). A moderate decrease of mt delta psi induced a reduction of mitochondrial NADH, followed by exposure of phosphatidyl serine and then by chromatin condensation, 36% of nuclei being condensed 60 min after FCCP treatment. During these stages, mitochondrion morphology was fully preserved. In contrast, no chromatin condensation was observed after a rapid and total dissipation of mt delta psi. These results suggest that a partial decrease of mt delta psi would allow mitochondrial functions required to trigger apoptosis to be sustained.

Efficiency of metabolic screening in childhood cardiomyopathies.

AIM: To estimate the efficiency of metabolic screening in children's cardiomyopathy. METHODS AND RESULTS: Blood glucose, lactate, pyruvate and ketone body, and carnitine levels were measured in 58 children referred with a cardiomyopathy of unknown origin. Organic acids, amino acids, oxidation of [1-14C] fatty acids to CO2 and dehydrogenation of [9,10(-3)H] fatty acids by lymphocytes were measured. Mitochondrial respiratory chain complex activity was measured in skeletal muscle and in endomyocardial biopsies. Acid a-glucosidase activity was measured in infants with hypertrophic cardio-myopathy. The prevalence of metabolic disorders was 22.4% (13/58-CL95%; 11.4-33.3%): four infants had a storage disease (Pompe's disease (3), Hurler's disease (1); two patients had a fatty acid beta-oxidation defect (systemic carnitine deficiency (1) and very-long chain acyl-CoA dehydrogenase deficiency (1)); respiratory enzyme deficiency was diagnosed in seven patients. This defect was confined to the myocardium in six. In the remaining 45 patients, metabolic screening was unrevealing. CONCLUSION: Metabolic screening should be performed in all children with cardiomyopathy as the prevalence of metabolic disorders is high in this population. This may help to define therapeutic strategy and to improve genetic counselling.

[Munchausen syndrome by proxy]. / Le syndrome de Munchausen par procuration.

Munchausen syndrome by proxy is a form of child abuse presenting as a disease produced or simulated by a parent, the mother in most cases. Its diagnosis is uneasy because of its miscellaneous and unusual clinical presentation and of the misleading apparently normal attitude of the parents. Physicians may participate in the abuse by insistently looking for diagnostic and therapeutic measures, therefore contributing to the significant mortality of the syndrome. It is therefore important that physicians consider Munchausen syndrome in any ambiguous situation in order to protect the child by an early diagnosis.

[Idiopathic peri-cerebral enlargement in infants: simple anatomical variant or hemorrhagic risk factor?]. / Epanchement péricérébral idiopathique du nourrisson: simple variante anatomique ou facteur de risque hémorragique?

BACKGROUND: Idiopathic subarachnoid space enlargement (ISSE) is usually regarded as a benign lesion. CASE REPORTS: Two infants, 6 and 8 months old respectively, were hospitalized for neurological disorders revealing subdural hematoma. The first one was drowsy after an apparent life threatening event. The CT scan showed a recent subdural hematoma with ISSE. The outcome was spontaneously uneventful. The second patient presented a febrile hemiconvulsion preceding a status epilepticus. The diagnosis of empyema complicating subdural hematoma with ISSE was done on MRI. Recovery occurred after a 3 week course of parenteral antibiotics and 1 year of antiepileptic treatment. In these two cases, there was no history of head injury and the retrospective study of cranial perimeter growth curves showed acceleration before the acute event. CONCLUSION: The reputation of benignity is not usurped regarding the ISSE. Nevertheless, it must be recognized as a factor furthering emergence of subdural hematoma, even in absence of injury context.