The diagnostic performance of sensitive cardiac troponin assays is excellent, and these assays can substantially improve the early diagnosis of acute myocardial infarction, particularly in patients with a recent onset of chest pain. (ClinicalTrials.gov number, NCT00470587.)

Cultured monolayers of spontaneously contracting chick embryo ventricular cells were perfused with culture medium containing ouabain. Contractile state was monitored by an optical-video system recording amplitude and velocity of cell wall motion. Positive inotropic effects of 2.5 • 10 -7 to 10 -6 M ouabain were manifest within 1.5-2 min, and reached a stable plateau within 5-6 min. The inotropic effect was fully reversed within 5 min after washout of ouabain. Inhibition of uptake of 4~K+ (or the K + analog S6Rb+) and efflux of 24Na+ occurred 1.5-2 min after exposure to ouabin. The degree of inhibition of transport was closely related to the magnitude of the positive inotropic effect throughout the ouabain concentration range 10 -7 to 10-6M. After washout of ouabain from monolayers, the monovalent cation active transport rate returned to normal within 1 min. Thus, both the onset and offset of inotropic action of ouabain were closely related temporally to inhibition of the sodium pump. Exposure to ouabain caused significant increases in exchangeable Na and Ca contents that appeared to be developed within 5 min. These data support the hypothesis that inhibition of monovalent cation active transport by ouabain is causally related to the development of positive inotropy and are consistent with modulation of Ca content by intracellular Na + via the Na+-Ca 2+ exchange carrier mechanism.

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Dementia of the Alzheimer type, senile onset (SDAT), and multi-infarct dementia (MID) exhibit differences in cerebrovascular blood flow velocity profiles, which were investigated by means of transcranial Doppler sonography. The pulsatility indices (PI), as angle-independent parameters of peripheral vascular resistance measured in the basal cerebral arteries, were significantly increased in MID patients with respect to SDAT cases. In an analysis of the correlations between several variables and the magnitude of PI, we found strong inverse correlations of the CAMCOG score, and strong direct correlations of the blood pressure and the duration of illness, with the PI of all basal cerebral arteries only in MID patients. In SDAT patients, we found a direct correlation between the Hachinski ischemia score and the PI of all basal cerebral arteries. All 3 ischemia scores (Hachinski, Rosen, Loeb and Gandolfo) were significantly correlated with the PI of the middle cerebral and basilar arteries. By analyzing the correlations of the single items of the 3 different ischemia scores with the PI values obtained, we only found a clearcut correlation with the item focal neurological signs. Thus, our findings stress the relative importance of a concomitant cerebrovascular factor in the development of dementia in old age, even in patients with probable SDAT. A raise of the PI in the basal cerebral arteries allows early suspicion of a cerebrovascular factor even in only slight dementia so that possible risk factors for further aggravation of this type of vascular dementia might be detected and treated early in the course of disease.

Primary degenerative dementia of the Alzheimer type (DAT) and multiinfarct dementia (MID) exhibit differences in cerebrovascular blood flow velocity profiles, which were investigated by means of transcranial Doppler sonography. The pulsatility indices, as angle-independent parameters of peripheral vascular resistance, measured in middle cerebral and basilar arteries of patients with MID, were significantly increased (P < 0.005) with respect to cases of primary DAT and to healthy age-matched controls. Approximately 75% of all MID patients exhibited small-vessel disease rather than thromboembolism from the extracranial arteries and the heart, as judged by extracranial and transcranial Doppler sonographies, computerized cerebral tomographies, EEGs, and, if necessary, 2-D echocardiographies.