Incidence and subtypes of early-onset dementia in a geographically defined general population.

OBJECTIVE: To estimate the incidence of early-onset dementia (EOD) and to compare the clinical characteristics of EOD vs late-onset dementia (LOD) in a geographically defined area. METHODS: We used data from the Registry of Dementia of Girona (ReDeGi), an epidemiologic surveillance system of dementia. The ReDeGi is a standardized clinical registry of new dementia cases diagnosed in the 7 hospitals of the Health Region of Girona (Catalonia, Spain), which encompasses an area of 5,517 km(2) and 690,207 inhabitants. EOD cases were defined as those patients residing in the target area at the time of diagnosis who were diagnosed with dementia with an age at onset of symptoms before 65 years. RESULTS: The ReDeGi registered 2,083 patients between January 1, 2007, and December 31, 2009 (6.9% EOD). The incidence rate of EOD for the age range 30-64 was 13.4 cases per 100,000 person-years (95% confidence interval 11.3-15.8). Alzheimer disease was the most frequent cause of EOD (42.4%), followed by secondary dementia (18.1%), vascular dementia (13.8%), and frontotemporal dementia (9.7%). EOD cases at the time of diagnosis were less impaired on the Mini-Mental State Examination and had a greater score on the Blessed Dementia Rating Scale behavior subscale than LOD cases. The frequency of a personal history of depression was higher in EOD cases. CONCLUSIONS: The incidence of EOD was less than 6 cases per 100,000 person-years in the age group 30-49 years; in the age group 50-64 years, the incidence rate was 3-fold higher and doubled with each 5-year increase.

5-Hydroxytryptamine inhibits the tachycardia induced by selective preganglionic sympathetic stimulation in pithed rats.

It has been shown in several species that serotonin (5-hydroxytryptamine; 5-HT) is able to inhibit the responses produced by sympathetic stimulation in a wide variety of blood vessels and other organs, including the heart. However, in pithed rats, the analysis of potential sympatho-inhibitory actions of 5-HT is hampered by the fact that 5-HT (given as i.v. bolus injections) produces tachycardia per se. Moreover, most studies have investigated 5-HT-induced sympatho-inhibition at only one frequency of stimulation. Thus, the present study set out to find the experimental conditions to overcome these problems. In this regard, we analyzed the potential ability of 5-HT, administered as i.v. continuous infusions, to inhibit the tachycardia caused by stimulation of the preganglionic (C7-T1) sympathetic outflow in pithed rats. Sympathetic cardiostimulation (0.01-3 Hz) resulted in frequency-dependent increases in heart rate; these responses were potentiated after desipramine (50 microg/kg, i.v.). During continuous infusions of 5-HT (3.1-10 microg/kg.min, i.v.), but not saline, the sympathetically-induced tachycardia was dose-dependently inhibited in both control and desipramine-pretreated rats. This inhibitory effect of 5-HT was significantly more pronounced at lower frequencies of stimulation. In contrast, the above infusions of 5-HT did not inhibit the tachycardia induced by i.v. bolus injections of noradrenaline in both control and desipramine-pretreated rats. Taken together, the above findings confirm that 5-HT induces inhibition of the sympathetic chronotropic outflow in the rat by acting at receptors located prejunctionally, without evoking tachycardia, over a wide range of stimulation frequencies.

Effect of a new synthetic C-nucleoside (EDTO) on cell proliferation.

The growth of Ehrlich ascite tumour cells obtained from NMRI mice and the proliferative response of T-lymphocytes from human peripheral blood in the presence of a mitogen: phytohemagglutinin (PHA) were studied in order to see what effect 2-(alpha and beta-D-erythrophuranosyl)-6,6-dimethyl-4,5,6,7-tetrahydroindol+ ++-4-one (a new synthetic C-nucleoside) had on cell proliferation. The uptake of 3H-thymidine was used as an index of cellular growth. The results show that although this C-nucleoside did not significantly alter the growth of the tumour cells, it did significantly inhibit the proliferation of T-lymphocytes.