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Biomedical subjects

A Brun

Publications and source records attributed to A Brun.

At least 271 records · Page 15Linked to original sources
PubMedDate not supplied

Regional study of acid hydrolases and lysosomal membrane properties in the normal human brain at various ages.

Acid hydrolases and lysosomal membrane properties were studied at various ages in the normal human brain. In CSF and four brain regions, the inferior olive, the cerebellar cortex, the caudate nucleus and the frontal cortex were thus beta-galactosidase, beta-glucosidase, alpha-mannosidase, hexosaminidase and acid phosphatase biochemically quantitated at ages varying between 2 and 89 years of age. Also the membrane latency for acid phosphatase was studied in these regions. No major regional quantitative differences were found with regard to the enzymes studied. Their kinetic properties were also defined. There appeared to exist a regional and intra-areal variation in lysosomal membrane permeability. There was, however, no age related increase in total enzyme contents. The possibility significance of these findings are discussed with reference to the aging process.

Acid Phosphatase↗
PubMedDate not supplied

Hydra head activator-like immunoreactivity in human brain astrocytomas grade III-IV and the surrounding brain tissue.

We have developed a specific and sensitive radioimmunoassay for the hydra head activator neuropeptide (HHAP). The antibody recognizes the C-terminal portion of HHAP and shows no cross-reactivity with other neuropeptides. The assay allows measurement of HHAP-like material in tissue extracts with a minimum detectable concentration of 22 fmol/ml standard HHAP (2 fmol/tube). The concentration of immunoreactive (IR) HHAP in histopathologically characterized tissues was determined in 43 specimens from astrocytomas grade III-IV and surrounding brain tissue from 18 patients. Twenty-two control specimens of gray and white matter and five from hypothalamus were taken from 5 brains at autopsy. The concentration of IR-HHAP in the brain tumors, including the actively growing tumor front, is lower than in normal brain, and thus appears not to act as a growth factor. High performance liquid chromatography (HPLC) of extracts of hypothalamus and tumors revealed two major peaks of IR-HHAP; one eluted with the same elution volume as synthetic HHAP. HPLC of cerebral cortex extracts revealed only one major peak of IR-HHAP eluting close to the void volume, which may indicate a posttranslational processing variability of HHAP in different brain regions. By immunocytochemistry HHAP immunoreactivity was localized to the cytoplasma of neuroectodermal cells.

Amino Acid Sequence↗
PubMedDate not supplied

[Emotional and attentive interferences and slow cerebral potentials (CNV-P 300) (author's transl)].

A study was conducted to establish possible correlations between electrophysiological indices and performance under neutral situations and those involving completing a double task of increasing complexity, by studying CNV and P 300 in young healthy men. The results demonstrated that: 1. After habituation, the CNV amplitudes were not related to performance. A significant correlation was noted only during the most complex tasks. 2. The CNV appears to depend mainly on endogenous factors, that is to say the aptitude and readiness of an individual to treat the information, rather than on the performance resulting from this treatment. 3. The amplitude of the P 300 is related to performance, as a function of detection rate and the complexity of the tasks. The functional duality of the CNV and the differences between it and the P 300 have been emphasized. The indices obtained from slow potentials appear to be of value for an evaluation of behaviour. Rather than analyzing the characteristics of the potentials in a supposedly "neutral" situation it would appear preferable to establish, from the indices, profiles of individual reactivity and adaptation to different experimental situations.

Action Potentials↗
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

Frontal dysfunction and frontal cortical synapse loss in alcoholism--the main cause of alcohol dementia?

Alcoholics often develop personality and behavioural changes, social and personal neglect, confabulation, lack of insight, empathy and emotional control. Such symptoms would increase the risk of engagement in and exposure to acts of violence and criminal activities carrying a risk of physical damage including head trauma and violent death. This was the case in at least 4 of the studied cases. A structural basis for such frontal lobe symptoms was looked for in a forensic material of 18 alcoholics, compared with an age-matched control group with regard to liver disease, brain changes of the Wernicke-Korsakoff type and cortical, especially frontal cortical changes. The salient finding was a consistent pattern of synapse loss in the superior laminae of the frontal cortical area 10 of Brodman in heavy drinkers, not related to liver disease or possible previous mental disease. The synapse loss is more likely related to alcohol, possibly mediated through vitamin B deficiency. Brain stem lesions as a source of additional symptoms cannot be dismissed. This pattern of synapse loss in alcoholism has not been described previously. The cortical changes are closely similar to those found in frontotemporal dementia, and seem to be a plausible main cause of the alcoholic frontal symptomatology and alcoholic dementia.

Adult↗
PubMedDate not supplied

Neuropathological brain mapping.

Neuropathological brain mapping is enabled by extensive semiserial sectioning with whole brain coronal microscopical sections prepared from every 5 to 15 mm. By this method not only type of change but also distribution and regional severity can be assessed, which is fundamental for a correct neuropathological diagnosis. This has proved to be of vital importance for the correlation and validation of the clinical symptoms and brain imaging findings in cases of organic dementia, and vice versa for the interpretation of the neuropathological findings. Different patterns for the distribution and types of changes have been revealed for Alzheimer's disease and frontal lobe degeneration, as well as in vascular dementia where pure subgroups could be identified. In the very aged, the mapping of several types of mild lesions have been shown to cooperate to cause a summational dementia.

Alzheimer Disease↗
PubMedDate not supplied

Pathology and pathophysiology of cerebrovascular dementia: pure subgroups of obstructive and hypoperfusive etiology.

The brains of 175 consecutive autopsy cases of dementia, clinically studied prospectively, were analyzed pathoanatomically with regard to type, size and site of lesions. Pure groups of vascular dementia caused by large or small vessel disease and by hypoperfusion could be defined. The infarcts were either complete with a more or less pronounced incomplete perifocal component or of an incomplete type only. Incomplete infarction appears to be an important and yet little appreciated cause of brain dysfunction. These groups could be used as a basis for a pathoanatomical classification of vascular dementias. Vascular dementia is much more common than generally assumed.

Aged↗
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Cortical synaptic changes and gliosis in normal aging, Alzheimer's disease and frontal lobe degeneration.

The most important new development during recent years in the field of degenerative dementia concerns synaptic pathology. So far it has been investigated in some regions and some cortical laminae in Alzheimer's disease (AD). The present communication is a more comprehensive study of all laminae in four different regions, the prefrontal, parietal, inferior temporal and posterior cingulate cortex. Against the background of normal aging, AD was compared with another degenerative disorder, frontal lobe degeneration of non-Alzheimer type (FLD). The synapse density was measured using synaptophysin as a marker. Astrocytes were also counted in the molecular layer. In normals, the cortex showed successively lower synaptic density from layer I to layer VI and relatively lowest density in the prefrontal cortex and a general decline with increasing age. A 46-49% decrease in synaptic density was found in all laminae in all regions of AD brains, a finding different from that in FLD. The number of astrocytes increased significantly in the prefrontal cortex both in AD and FLD but parietally only in AD. These results contribute to the understanding of normal synaptic organization of cortex, demonstrate the laminar and regional distribution of synaptic loss in AD and underscore the difference between AD and FLD. The gliosis appears to be secondary to the neurodegenerative changes. Synaptic loss is likely to be a common pathogenetic feature of neurodegenerative disorders and a likely cause of clinical symptoms and regional metabolic decrements in dementia.

Aged↗
PubMedDate not supplied

Synaptophysin immunoreactivity is stable 36 h postmortem.

The effects of postmortem time, age and tissue storage time on synaptic density were investigated in the prefrontal cortex of human brains. Thirty normal cases and 10 patients with a variety of neurologic diseases were studied, using quantitative immunohistochemistry with a monoclonal antibody to synaptophysin. Synaptophysin immunoreactivity was stable during the first 36 h after death, showing no significant change at 1, 8, 12, 24 and 36 h postmortem in normals. However, at 48 and 72 h postmortem, synaptophysin immunoreactivity decreased significantly. A similar pattern of postmortem changes was found in the disease group. In 14 normal cases with a wide range of ages, a significant reduction in synaptic density with age was observed while the time of tissue storage as paraffin-embedded blocks had no significant effect on the synaptophysin immunoreactivity. These results support the validity of using synaptophysin immunohistochemistry as a measure of synaptic density in human brain autopsied within 36 h of death and stored as paraffin-embedded blocks for a long time.

Age Factors↗
PubMedDate not supplied

Frontal lobe degeneration of non-Alzheimer type revisited.

The neuropathology of frontal lobe degeneration of non-Alzheimer type was reevaluated on the basis of a new material of 13 cases against the background of experiences from earlier published 16 cases. The salient neuropathological feature was an unspecific neuronal degeneration of superficial cortical layers of the frontal and to some extent the temporal lobes without markers for Alzheimer's, Pick's or Lewy body diseases and there were no indications so far of a prion etiology. The consistency of histopathological features are taken to indicate a disease entity, also identified by other authors. It is tentatively grouped together with progressive and aphasic dementia, similar cases in the literature and possibly also Pick's disease and ALS with dementia.

Aged↗
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

Exclusion mapping in familial non-specific dementia.

We present genetic linkage data in a large family in which non-specific dementia is inherited as an autosomal dominant trait. We have analyzed 45 highly polymorphic microsatellite sequences and excluded a quarter of the genome as the site of the pathogenic mutation in this family.

Adult↗
PubMedDate not supplied

Hemodynamic comparison of Medtronic intact bioprostheses and bileaflet mechanical prostheses in aortic position.

Hemodynamic properties of both bioprostheses and mechanical valves have improved over the years, however, direct comparison between second-generation porcine and bileaflet valves is rare. Therefore, by the mean of Doppler echocardiography, we determined hemodynamic performances in 45 patients with Medtronic Intact bioprostheses in the aortic position and in 67 patients with bileaflet mechanical valves. Differences in pressure gradients between the two groups were essentially attributable to differences in annulus size. Indeed when the transvalvular gradient was stratified according to annulus size, mean values were no longer significantly different between Medtronic Intact porcine valves and bileaflet mechanical valves for each annulus size. In conclusion, Medtronic Intact bioprostheses in the aortic position exhibit similar hemodynamic characteristics compared to bileaflet mechanical valves.

Aged↗
PubMedDate not supplied

Proton magnetic resonance relaxation times T1 and T2 related to postmortem interval. An investigation on porcine brain tissue.

In order to establish the validity of in vitro determination of the proton magnetic resonance (MR) relaxation times T1 and T2 in brain tissue at increasing time delay after death or operative excision, 81 brain tissue samples from 23 pigs were analyzed repeatedly. These samples, representing cortex, caudate nucleus and white matter, were studied microscopically after MR measurements. The T1 values exhibited no time dependence and the T2 values decreased slightly during the interval 2 to 90 hours after death. The samples were stored at +8 degrees C between the measurements. These results indicate that reliable in vitro measurements can be obtained in autopsy or surgical brain tissue specimens within 90 hours after death or excision, if handled properly.

Animals↗
PubMedDate not supplied

Regional differences in the proton magnetic resonance relaxation times T1 and T2 within the normal human brain.

The proton magnetic resonance (MR) relaxation times T1 and T2 were determined in autopsy specimens from 13 different regions of normal human brains. One hundred and seventy-four tissue samples from 25 brains were examined in a pulsed MR analyzer of 0.25 T and were then also studied histologically. There were regional differences in T1 and T2 within the cerebral gray matter but not within the white matter. These regional differences might reflect the different composition and cytoarchitectonic structure of the cortical regions and should be taken into consideration in the interpretation of cortical lesions on MR images.

Aged↗