Biomedical subjects

U Passant

Publications and source records attributed to U Passant.

29 records · Page 2Linked to original sources

PubMed1993

Cortical blood flow during head-up postural change in subjects with orthostatic hypotension.

Regional cerebral blood flow was measured with the 133-Xenon inhalation method in seven healthy subjects with orthostatic hypotension not due to autonomic failure (i.e. non-neurogenic clinical disorder). Measurements were performed during supine rest and during head-up tilt (70 degrees). All subjects had a consistent drop in systolic blood pressure and the typical symptomatology of orthostatic hypotension. The results showed lower mean hemispheric blood flow during head-up tilt than during supine rest. In addition, a consistent and significant redistribution of the regional flow values was seen, with a reduction in frontal and an increase in postcentral areas. The frontal flow decrease during tilt was more marked than in subjects without orthostatic hypotension and was not related to variations in the level of PCO2 or to respiration. In contrast to the clinical symptoms of orthostatic hypotension (dizziness, nausea, visual disturbances, and in some cases syncope), the cortical blood flow reduction was, however, relatively moderate.

Adult↗

PubMed1992

Redistribution of blood flow in the cerebral cortex of normal subjects during head-up postural change.

Regional cerebral blood flow was measured in 21 normotensive subjects during supine rest and during head-up tilt to 70 degrees. The results showed significant and consistent regional cerebral blood flow changes in the frontal areas with lower relative flow distribution values (percentage of mean flow) during head-up tilt than during supine rest. The lower frontal flow distribution values during tilt were not related to habituation, to repeated measurements, or to the estimated level of arterial CO2 which was derived from expired end-tidal CO2 levels. None of the subjects had orthostatic hypotension and there was no significant difference in mean hemispheric blood flow between lying down and standing up. There was no significant gender difference in regional cerebral blood flow, although female subjects tended to have higher mean hemispheric flow than males in both postures. It remains to be established whether the flow decreases in the frontal cortex are caused by cerebral functional factors or by haemodynamic mechanisms.

Adult↗

PubMed1992

Frontal lobe degeneration of non-Alzheimer type.

In a longitudinal prospective study of dementias, several hundred cases have been examined from a clinical, brain imaging, neurochemical and neuropathological point of view. Frontal lobe degeneration of non-Alzheimer type (FLD) was the second most common primary degenerative dementia found in about 10% of the material. FLD has a consistent pathology and a characteristic clinical picture, which have been described by several independent research groups. The cortical degeneration mainly involves frontal or frontotemporal grey matter, without the circumscribed or knife-blade atrophy seen in Pick's disease. The degeneration involves predominantly frontal areas, including the insula and cingulate gyrus in its anterior parts. The striate body is normal or only slightly altered. The pathological changes are non-specific, with neuronal loss, slight gliosis and spongiosis but none or few senile plaques, tangles, congophilic vessels or Pick cells. Pathological changes are in some respects similar to those in amyotrophic lateral sclerosis. FLD is a slowly progressive dementia with personality changes, lack of insight, disinhibition, stereotypy and later apathy. There is also progressive dynamic aphasia which ends in mutism and amimia. Memory, spatial ability and receptive language functions are comparatively spared. Psychotic symptoms, emotional reactions, hypochondriasis and a Klüver-Bucy-like syndrome are sometimes observed. Electroencephalography is normal, at least during the early stage, while functional brain imaging such as regional cerebral blood flow reflects the frontal pathology. It is possible to achieve early diagnosis and differentiation from Alzheimer's disease and cerebrovascular dementia by clinical examination with neuropsychological assessment supported by brain imaging, and in the future probably various biological markers. The aetiology is unknown but there is a positive family history for dementia of similar type in about 50% of post-mortem verified cases.

Cerebrovascular Circulation↗

PubMedDate not supplied

Blood pressure and drug treatment in clinically diagnosed Lewy body dementia and Alzheimer's disease.

The aim of the study was to investigate arterial blood pressure (BP) and the use of pharmacological treatment in patients with Lewy body dementia (cLBD) and Alzheimer's disease (cAD) diagnosed on clinical grounds. BP and pharmacological treatment was analysed based on the medical records of 200 deceased dementia patients. Forty-eight cases with LBD and 45 AD were diagnosed using clinical criteria. The patients, who died between 1985 and 1994, were part of a prospective longitudinal dementia project. The majority of the cases were examined and cared for at the psychogeriatric and psychiatric departments. BP levels were very similar at an early stage of dementia but there was a marked decrease during the course of dementia in cAD and cLBD. The cLBD cases became hypotensive during the course of dementia to a significantly greater extent and also had a more pronounced drop in systolic BP at orthostatic testing compared to the cAD cases. cLBD and cAD were prescribed neuroleptics and medication potentially associated with hypotension to the same extent. The total number of these drugs was however higher in cLBD than in cAD. Antiparkinsonian treatment was, as expected, more common in cLBD compared to cAD. The findings suggest that insufficient BP regulation and drug treatment could affect the clinical picture of dementia, particularly in cLBD patients.

Journal Article↗

PubMedDate not supplied

Decreased monoamine metabolites in frontotemporal dementia and Alzheimer's disease.

The concentrations of the monoamine metabolites homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA) and 3-methoxy-4-hydroxyphenylglycol (HMPG) in the cerebrospinal fluid (CSF) of patients with clinical frontotemporal dementia (FTD; n = 30), early onset Alzheimer's disease (EAD; n = 33), late onset Alzheimer's disease (LAD, n = 27) and normal controls (n = 31) were determined using HPLC. ANCOVA showed no significant effect of neuroleptic medication, extrapyramidal signs, myoclonia or gender on the CSF levels of the monoamine metabolites. Homovanillic acid was significantly reduced in all diagnostic groups (FTD, p = 0.0002; EAD, p = 0.016; LAD, p = 0.013). 5-Hydroxyindoleacetic acid was significantly reduced in EAD (p = 0.013) and in LAD (p = 0.0014), and HMPG was reduced in LAD only (p = 0.020). HMPG was significantly higher in FTD compared to EAD (p = 0.0005) and LAD (p = 0.0003). CSF-5-HIAA was significantly reduced in patients with antidepressant medication (p = 0.006). ANCOVA within the FTD group showed no significant effect of neuroleptic or antidepressant medication, extrapyramidal signs, myoclonia, gender or FTD subtype on the CSF levels of the monoamine metabolites. The results suggest that CSF-HMPG might differentiate FTD from EAD and LAD, but not from normals.

Adult↗

PubMedDate not supplied

Magnetic resonance imaging and histopathology in dementia, clinically of frontotemporal type.

The magnetic resonance imaging (MRI) and computed tomography findings in 28 patients with the clinical diagnosis of frontotemporal dementia (FTD) were compared with the findings in a control group of 76 individuals without dementia or stroke. A pattern of frontal and temporal atrophy with predominantly frontal white matter changes was found in the FTD patients, and this was significantly different from the radiological findings in the control group. Six of the FTD patients have undergone autopsy. Histopathological evaluation showed a primary cortical degenerative disease (frontal lobe degeneration of non-Alzheimer type) in 3 of them, and primary white matter disorder, mainly frontal, of basically ischemic type (selective incomplete white matter infarction) in 3 of them. MRI could be a helpful tool to support the clinical diagnosis FTD, especially in young patients. MRI may also be helpful for the differentiation of a primary neurodegenerative from a mainly ischemic-vascular type of dementia.

Adult↗

PubMedDate not supplied

Functional imaging of the frontal lobes in organic dementia. Regional cerebral blood flow findings in normals, in patients with frontotemporal dementia and in patients with Alzheimer's disease, performing a word fluency test.

Patterns of functional cortical activation were studied by means of regional cerebral blood flow measurements, performed during rest and during a word fluency task in normal subjects (n = 22), in patients with Alzheimer's disease (n = 17), and in patients with frontotemporal dementia (n = 15). Although all groups showed a significant activation of the Broca's area during word production, the activation of the dorsolateral prefrontal cortex was clearly subnormal in both dementia groups. The frontal dysfunction was not explained by number of words produced, illness duration, or age. Thus, the results demonstrate that the word fluency task is a sensitive measure of frontal lobe function, and its incorporation in imaging studies may facilitate the detection of subtle functional impairment of the frontal lobes in organic dementia.

Adult↗

PubMedDate not supplied

Spectrum of frontal lobe dementia in a Swedish family.

The etiology of frontal lobe dementia of non-Alzheimer type (FLD) is still unknown. There is strong evidence of genetic factors with positive heredity. In this paper, a Swedish family, with several generations affected by FLD is described. In 3 patients typical FLD was confirmed postmortem. The clinical and neuropathological similarities between the patients are impressive.

Adult↗

PubMedDate not supplied

Regional cerebral blood flow in frontal lobe dementia of non-Alzheimer type.

Twenty-five out of 26 cases of autopsy-verified frontal lobe degeneration of non-Alzheimer type (FLD) were found to have focal frontal or frontotemporal blood flow reductions involving both hemispheres. The deviant case had an asymmetric frontal pathology only apparent on the right side. Focal reduction of blood flow in the frontal lobes is, however, a common and unspecific flow abnormality found in e.g. Pick's disease. Creutzfeldt-Jakob's disease, and in some cases of Alzheimer's disease. Low frontal flow has also been reported in schizophrenia and in toxic encephalopathy. Since a characteristic feature of FLD is a steady progress of the pathology, serial flow measurements extending over several years are especially informative.

Cerebrovascular Circulation↗

PubMedDate not supplied

Neuropsychological findings in frontal lobe dementia.

Neuropsychological investigations were performed on 18 patients with a clinical diagnosis of frontal lobe dementia supported by regional cerebral blood flow measurements. Nature and degree of cognitive impairment were examined with a comprehensive test battery. The results of the neuropsychological assessment could be described as three levels of cognitive impairment. The increasing levels of cognitive impairment were accompanied by corresponding levels of reduced cerebral blood flow in frontotemporal areas. No apparent relationship emerged between impairment level and illness duration, indicating a considerable individual variation in the clinical course of frontal lobe dementia.

Adult↗

PubMedDate not supplied

Functional activation of the frontal lobes. Regional cerebral blood flow findings in normals and in patients with frontal lobe dementia performing a word fluency test.

The present study examined the utility of the Word Fluency Test (WFT) as a frontal-lobe-activating test in brain imaging. Regional cerebral blood flow (rCBF) was measured during rest and during the WFT in 49 healthy volunteers and in 15 patients with frontal lobe dementia (FLD). The results showed a highly significant frontal lobe activation in 85% of the normal subjects. This finding was not related to age or to the level of performance on the WFT. A significant frontal activation was seen in 13 of the 15 FLD patients. The frontal flow increase did not reach normal levels, and was not related to age, illness duration or severity of clinical symptoms. The results suggest that the WFT is an ideal test to use in conjunction with functional imaging in normals as well as in patients with organic dementia.

Adult↗