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Biomedical subjects

M Lindau

Publications and source records attributed to M Lindau.

59 records · Page 4Linked to original sources
PubMedDate not supplied

IgE-mediated degranulation of mast cells does not require opening of ion channels.

Rat peritoneal mast cells respond to antigenic stimulation by releasing histamine through exocytosis. The dynamics of exocytosis can be investigated by dialysing single cells with patch pipettes using the whole-cell recording configuration of the patch-clamp technique. However, dialysed cells fail to respond to external stimuli such as compound 48/80 or antigens, suggesting that essential cytoplasmic components have been washed out. We have developed a new patch-clamp configuration in which the patch under the pipette tip is not disrupted but instead permeabilized, preventing the diffusion of large molecules out of the cell. In this configuration the cell responds to external stimulation, and the capacitance as well as the conductance of the cell membrane can be recorded during degranulation. On antigenic stimulation, the cell capacitance (proportional to plasma membrane area), after an initial delay, increases by a factor of about 3. This increase in capacitance is often preceded by a transient increase in conductance. Agents that block Ca-activated channels inhibit this conductance change without affecting the amplitude and time course of degranulation. We therefore conclude that, in contrast to excitable secretory cells such as chromaffin cells, mast cells do not use ion channels in stimulus-secretion coupling.

Animals↗
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Cognitive and behavioral differentiation of frontal lobe degeneration of the non-Alzheimer type and Alzheimer's disease.

Neuropsychological differences between 14 patients with a clinical diagnosis of frontal lobe degeneration of non-Alzheimer type (FLD) and 15 patients with a clinical diagnosis of Alzheimer's disease (AD) were studied. The most efficient psychometric predictors of FLD were Digit Symbol, estimation tasks, word list recall, and particularly the FAS word fluency test. Behavioral predictors of FLD and AD showed a double dissociation: regression and impulsivity characterized FLD, whereas lack of motivation and slowness were typical of AD. Cognitive and behavioral differences between groups were not related to the degree of dementia, as measured by Mini Mental State Examination, indicating that differences remained during progression of the diseases.

Affective Symptoms↗
PubMedDate not supplied

First symptoms--frontotemporal dementia versus Alzheimer's disease.

Frontotemporal dementia (FTD) is often misdiagnosed as Alzheimer's disease (AD). We hypothesized that the first symptoms associated with FTD would be different from those seen in AD and that the first symptoms in FTD would reflect loss of function in the frontal region with the greatest degree of degeneration. The objective of the study was to compare the earliest symptoms in patients with FTD and AD, and to delineate the symptoms that were associated with right, left or bilateral frontotemporal degeneration in FTD. The first symptoms in 52 FTD and 101 AD patients were determined in retrospect. Based on functional imaging studies, the FTD patients were divided into those with predominantly bilateral (n = 15), left-sided (n = 19) and right-sided (n = 18) patterns of atrophy. The results showed that disinhibition, social awkwardness, passivity and loss of executive function were more common in FTD, while memory loss was more common in AD. Disinhibition was greatest in the asymmetric right-sided group, language dysfunction was commonest in the asymmetric left-sided group and loss of executive function was most frequent in the bilateral group. In summary, different first symptoms appeared in FTD and AD, which may help distinguish between the diseases. The anatomic site for FTD largely determined the kind of first symptoms.

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