The calcium response of human T lymphocytes is decreased in aging but increased in Alzheimer's dementia.

BACKGROUND: A significant increase in the [Ca2+]i response of single T lymphocytes to mitogenic stimulation with phytohemagglutinin is reported for 27 Alzheimer patients compared with 27 healthy gender- and age-matched control subjects, regardless of gender. METHODS: The [Ca2+]i signals of T lymphocytes were assessed using the Fura-2-AM method. RESULTS: In Alzheimer's disease (AD) the reaction pattern is similar to that seen in a group of 27 young healthy control subjects who exhibited a marked [Ca2+]i rise after stimulation. During normal aging the reaction pattern of T cells is significantly attenuated in comparison to that found in young subjects. In healthy control subjects differences in age-related changes in calcium homeostasis are highly significant among women, young women showing the most intense cell response. CONCLUSIONS: The elevation of [Ca2+]i appears to be a prerequisite for apoptosis, which is suggested to be involved in the neuronal death occurring in AD. An increased [Ca2+]i in AD is consistent with processes leading to neurodegeneration in AD.

Altered Ca(2+)-homeostasis in single T-lymphocytes of depressed patients.

After stimulation of T-lymphocytes from healthy volunteers with the mitogen phytohemagglutinin (PHA) 40% of the cells exhibit an oscillatory increase in intracellular calcium concentration ([Ca2+]i). During depression the number of cells responding to PHA is reduced to 20%. These cells show a marked decrease in [Ca2+]i-reaction to stimulation and flattened oscillations. This reduction of mitogen-induced Ca2+ signals in T-cells of depressed patients appears to be a reliable state marker in depressive illness and is reversed upon successful treatment with interpersonal psychotherapy (IPT).

Frontocortical activity in children with comorbidity of tic disorder and attention-deficit hyperactivity disorder.

Comorbidity of tic disorder (TD) and attention-deficit hyperactivity disorder (ADHD) in children is common but not fully understood. Thus we investigated the effect of TD and ADHD on the amplitude of the postimperative negative variation (PINV) in children with combined tic + hyperactivity symptoms (TD + HA). PINV was chosen as an indicator of frontal lobe functioning that is closely related to self-regulation of behavior. PINVs of four groups of children (healthy controls, pure TD, pure ADHD, and combined TD + HA; total number 43) were elicited in an auditory warned reaction task in three conditions (control = CC, loss-of-control = LoCC, and lack-of-control = LaCC) at midfrontal (Fz) and midcentral (Cz) leads of the scalp. Effects of TD and ADHD were revealed only in the noncontrol conditions, being independent in the LaCC, but interactive in the LoCC. Thus, the additive model of psychopathological classification concerning the comorbidity of TD and ADHD was only partially supported by the observed pattern of psychophysiological results.

Coexistence of tics and hyperactivity in children: no additive at the psychophysiological level.

The objective of the present work was to study the effects of tic disorder (TD) and hyperactivity (HA) on slow cortical potentials in children with combined TD + HA symptoms. Being related to different processes of frontal lobe control over preparatory cortical activity, early and late components of the slow negative potentials (eSNP, ISNP) were examined. SNP amplitude was analyzed as reflecting the sufficiency of preparatory cortical activation; scalp distribution of SNP and relationships to reaction times were studied as revealing the efficiency of task-related region-specific activation. It was hypothesized that if the effects of TD and HA were independent, additive effects on SNP amplitudes would be observed in children with coexisting TD and HA symptoms (TD + HA). Differences in SNP scalp distribution between control and patient groups were predicted to occur mainly over the frontal brain areas. Four groups of children (n = 10/11 in each group) were studied: healthy controls, pure TD, pure attention deficit hyperactivity disorder (ADHD), and combined tic and hyperactivity symptoms. SNPs were recorded in an auditory warned reaction time task (S1-S2-RT) from 8 electrode locations. According to the results, the effects of TD and HA on the sufficiency of task-dependent cortical activation were different, with only the TD factor related to lower SNP amplitudes. Nevertheless, deviant patterns of scalp distribution were found for pure ADHD patients, which suggested an inefficiency in involving the adequate task-related areas. For TD + HA children, like pure TD, lower SNP amplitudes and similar distribution and correlation patterns were present. Thus, according to amplitude, topography, and correlation criteria, TD + HA does not appear to be a subgroup of HA disorder but seems more similar to pure tic disorder.