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Biomedical subjects

J Haan

Publications and source records attributed to J Haan.

At least 127 records · Page 7Linked to original sources
PubMed1991

Autonomic nervous system tests depend on resting heart rate and blood pressure.

In order to study the effects of baseline blood pressure and heart frequency on autonomic function tests, 75 normal subjects (aged 8-96 years) were investigated. Heart rate variability was studied at rest, during deep breathing, following standing up and during a Valsalva manoeuvre. Blood pressure changes were recorded during standing up and during sustained handgrip. Responses were described as ratios and as differences to study the efficacy of both methods. Multiple regression analysis showed that significant relationships with the resting heart rate existed for ratios but not for differences. The blood pressure rise in the sustained handgrip test showed a significant relationship with resting blood pressure regardless of the description method. As expected, relationships with age existed for all four heart rate tests regardless of the description method. The blood pressure responses were not significantly related to age. We advise that heart rate test results should be presented as differences, as this avoids the need for correction for the resting heart rate. Correction for the resting blood pressure improves the accuracy of the standing up blood pressure test. Correction for age remains necessary for heart rate tests but not for blood pressure tests.

Adolescent↗
PubMed1991

Hereditary cerebral hemorrhage with amyloidosis--Dutch type: its importance for Alzheimer research.

Alzheimer's disease is now commonly regarded as a form of 'amyloid encephalopathy'. Amyloid deposits in the cerebral blood vessels and parenchyma consist mainly of a unique protein called amyloid beta protein (A beta P), which has a molecular weight of 4 kDa and is 42 amino acids long. These deposits are thought to be of pathogenetic importance in Alzheimer's disease. Recently, therefore, attention has been focused on the process of turnover of the precursor of A beta P to amyloid fibrils, and the deposition and persistence of A beta P in this disease. The study of several other diseases with cerebral A beta P deposition can be informative in this respect, because they allow the comparison of different pathogenetic mechanisms that lead to this type of deposition. One of these diseases is hereditary cerebral hemorrhage with amyloidosis- Dutch type (HCHWA-D), which is the subject of this review.

Alzheimer Disease↗
PubMed1991

SPECT in the diagnosis of Alzheimer's disease and multi-infarct-dementia.

SPECT with Tc-99m HM-PAO as a radiopharmaceutical was performed in 17 patients meeting research criteria for Alzheimer's disease (AD), in 10 patients with a clinical diagnosis of multi-infarct-dementia (MID) and in 12 healthy volunteers. Regional tracer uptake was measured in frontal, parietal, and temporoparietal regions. A statistically significant decrease of tracer uptake in the temporoparietal region was found in AD-patients compared with controls. AD-patients showed less activity in this region than MID-patients, but this difference did not reach statistical significance. In both AD- and MID-patients decrease of tracer uptake was not correlated with dementia severity. We conclude that SPECT brain imaging is not yet ready for routine use in the distinction between AD and MID.

Aged↗
PubMed1991

Visual evoked potentials and background EEG activity in migraine.

To investigate whether quantification of the background EEG during a visual evoked potential (VEP) study is of value for the diagnosis of migraine we studied 8 unmedicated migraineurs between attacks, and 10 age-matched controls. Three paradigms were used: the first two concerned pattern-reversal VEPs with different analysis times (500 and 1500 ms), and in the third paradigm the pattern did not reverse. Power spectra were calculated for individual responses, and the delta, theta, alpha and beta areas of the averaged spectra were noted as indicators of background reactivity. Alpha and beta powers were consistently but not significantly higher in the migraine group. The difference was too small to be of value as a diagnostic test. Alpha power was (not significantly) lower in the presence of photic stimulation than in its absence. As this was the case in both groups photic stimulation does not explain the higher alpha powers in the migraine group. We conclude that EEG background activity during the VEP does not distinguish reliably between migraineurs and controls.

Adult↗
PubMed1991

Cognitive function after spinal or general anesthesia for transurethral prostatectomy in elderly men.

Cognitive functions in 53 elderly men who underwent a transurethral prostatectomy were assessed pre-operatively and 4 days and 3 months post-operatively. Thirteen patients had a preference for one particular type of anesthesia, and the remaining 40 were randomly allocated to receive either spinal or general anesthesia. Cognitive function was not different between the groups receiving different types of anesthesia at either time point and did not decrease post-operatively. No pre- or perioperative variable could distinguish the subgroup of patients who had a post-operative decrease of 2 points or more on the Mini-Mental State Examination. No difference in post-operative performance was found in the patient groups with pre-operative Mini-Mental State Examination scores above or under their age-specific norm. It is concluded that neither hospitalization nor the two forms of anesthesia investigated cause a decrease in cognitive function in elderly men.

Aged↗
PubMed1991

Hereditary cerebral hemorrhage with amyloidosis--Dutch type: a congophilic angiopathy. An overview.

Hereditary cerebral hemorrhage with amyloidosis--Dutch type (HCHWA-D) is characterized by recurrent cerebral hemorrhages and dementia at a relatively young age. The symptoms are caused by extensive deposition of amyloid in cerebral arterioles and leptomeningeal arteries. A point-mutation in the beta-protein precursor gene on chromosome 21 is the underlying cause of the disease. This paper summarizes the clinical, radiologic, pathologic, and genetic features of this disease, with special attention to the relation between HCHWA-D and Alzheimer's disease, which is also characterized by beta-protein deposition.

Amyloid beta-Peptides↗
PubMed1991

DNA diagnosis for hereditary cerebral hemorrhage with amyloidosis (Dutch type)

Hereditary cerebral hemorrhage with amyloidosis of the Dutch type (HCHWA-D) is tightly linked to the Alzheimer amyloid precursor protein gene on chromosome 21, which codes for the amyloid beta-protein. A point mutation detected at position 1852 of the amyloid precursor protein gene in four HCHWA-D patients was hypothesized to be the basic defect. This study proves that 22 HCHWA-D patients from three pedigrees all carry this point mutation, whereas the mutation is absent in escapees from the HCHWA-D families as well as in randomly selected Dutch individuals. A mutation-specific oligonucleotide is now available for the confirmation of the HCHWA-D diagnosis. Therefore, presymptomatic testing and prenatal evaluation of individuals at risk in the HCHWA-D families is now feasible.

Aged↗
PubMed1990

Parenchymal preamyloid and amyloid deposits in the brains of patients with hereditary cerebral hemorrhage with amyloidosis--Dutch type.

Hereditary cerebral hermorrhage with amyloidosis--Dutch type, one of the 'cerebral beta-amyloid diseases', like Alzheimer's disease, is characterized by extensive deposition of amyloid in small cerebral vessels. We investigated the presence of parenchymal beta-protein deposits in two Dutch patients with hereditary cerebral hemorrhage with amyloidosis. Immunostaining with anti-SP28 revealed a full spectrum of these deposits, varying from preamyloid deposits to burned-out plaques. However, their density is less than in Alzheimer's disease, and immunostaining with Alz50 and anti-PHF did not show abnormal neurites in and around amyloid deposits in these two patients.

Amyloid beta-Peptides↗
PubMed1990

Amyloid beta protein precursor gene and hereditary cerebral hemorrhage with amyloidosis (Dutch).

Human hereditary cerebral hemorrhage with amyloidosis of the Dutch type (HCHWA-D), an autosomal dominant form of cerebral amyloid angiopathy (CAA), is characterized by extensive amyloid deposition in the small leptomeningeal arteries and cortical arterioles, which lead to an early death of those afflicted in their fifth or sixth decade. Immunohistochemical and biochemical studies have indicated that the amyloid subunit in HCHWA-D is antigenically related to and homologous in sequence with the amyloid beta protein isolated from brains of patients with Alzheimer's disease and Down syndrome. The amyloid beta protein is encoded by the amyloid beta protein precursor (APP) gene located on chromosome 21. Restriction fragment length polymorphisms detected by the APP gene were used to examine whether this gene is a candidate for the genetic defect in HCHWA-D. The data indicate that the APP gene is tightly linked to HCHWA-D and therefore, in contrast to familial Alzheimer's disease, cannot be excluded as the site of mutation in HCHWA-D.

Adult↗
PubMed1990

Hereditary cerebral hemorrhage with amyloidosis-Dutch type. Clinical and computed tomographic analysis of 24 cases.

Clinical and computed tomographic findings in 24 patients with hereditary cerebral hemorrhage with amyloidosis-Dutch type were reviewed. The common initial symptoms were headache and vomiting. Computed tomographic scans showed 50 hypodense and 49 hyperdense cortical lesions and in 20 patients the scans also showed generalized white matter hypodensity. Impairment of consciousness was related to the size of the hemorrhagic lesion. Dementia, seen in 11 patients, was related to the duration of the disease and the number of focal lesions on the computed tomographic scans, but not to the presence of white matter hypodensity. It is concluded that in hereditary cerebral hemorrhage with amyloidosis-Dutch type, lobar hemorrhages account predominantly for the acute clinical syndromes. The hemorrhages often have an irregular shape and are responsible for progression of the symptoms after an acute onset. Furthermore, cerebral amyloid angiopathy leads to a generalized abnormality of the white matter, probably due to chronic hypoperfusion.

Adult↗
PubMed1990

Dementia in hereditary cerebral hemorrhage with amyloidosis-Dutch type.

Sixteen patients with hereditary cerebral hemorrhage with amyloidosis-Dutch type were examined neuropsychologically. Abnormalities were found in all patients, and dementia was present in 12 of them. Three patients were tested twice at an interval of some years. All three exhibited a progressive intellectual deterioration and memory disturbance; in two of them there was no evidence of intercurrent strokes. Cerebral amyloid angiopathy can lead to dementia because it produces multiple focal cerebral lesions, but a chronic ischemic or metabolic effect on brain parenchyma may play a contributing role.

Aged↗
PubMed1990

Lymphocyte concanavalin A capping in hereditary cerebral haemorrhage with amyloidosis--Dutch type.

Lymphocyte capping with concanavalin A was studied in 11 patients with hereditary cerebral haemorrhage with amyloidosis (Dutch type) and 10 controls. No difference in capping was found between patients and controls. Abnormal lymphocyte concanavalin A capping has been reported in patients with the Icelandic type of cerebral amyloidosis and in patients with Alzheimer's disease, a disease in which cerebral amyloid angiopathy can also be found. The results suggest a difference in pathogenesis between the Dutch type of cerebral amyloidosis and the other amyloid diseases.

Aged↗
PubMed1990

Hereditary cerebral hemorrhage with amyloidosis--Dutch type. Tc-99m HM-PAO single photon emission computed tomography.

We performed single photon emission computed tomography (SPECT) and cerebral CT-scans in nine patients with hereditary cerebral amyloid angiopathy. CT-scans showed 23 focal hypodense lesions, 13 of which were visible on SPECT as a CBF-defect. One patient showed a CBF-defect on SPECT without CT-scan lesion and had a cerebral hemorrhage three months later in that particular region. In two additional patients, who were 50% at risk for this autosomal dominant disease, CBF-defects on SPECT, but no cortical lesions on CT-scan were found. CT-scans may be more sensitive than SPECT to detect chronic lesions caused by cerebral hemorrhages, but another possibility is that hemorrhages do not always lead to persistent CBF-defects. SPECT can show the effect of amyloid deposits on CBF before the angiopathy causes clinical symptoms.

Amyloidosis↗
PubMed1990

Cytochrome P450 and Parkinson's disease. Poor parahydroxylation of phenytoin.

Phenytoin-parahydroxylation capacity was determined in 24 patients with Parkinson's disease (PD) and 17 controls. Different function of the phenytoin-metabolizing cytochrome P450 subsystem was found in 6 patients, but in none of the controls. These results add to previous studies suggesting a relation between the pathogenesis of PD and the function of cytochrome P450 subsystems.

Aged↗
PubMed1990

The MPTP model: versatile contributions to the treatment of idiopathic Parkinson's disease.

In human and subhuman primates, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) produces irreversible clinical, biochemical and neuropathological alterations highly reminiscent of those observed in Parkinson's disease. The MPTP model has provided the best available tool to date for the assessment of efficacy and side-effects of symptomatic treatments of Parkinson's disease. In addition, the mechanism of action of MPTP has offered a basis for the development of novel therapeutic strategies aimed at the prevention of Parkinson's disease.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1990

Amyloid in central nervous system disease.

A review is presented of diseases of the central nervous system associated with amyloid deposition. The name amyloid is given to substances with particular physical characteristics which are independent of the chemical constitution of the proteins in the substance. Ideally, a classification of amyloid diseases should be based on the chemical composition of the amyloid deposits; this has only been partially realized. The best documented group of diseases with amyloid deposition in the central nervous system is the group of 'cerebral beta amyloid diseases', characterized by the deposition of beta-protein. This group includes: Alzheimer's disease, sporadic cerebral amyloid angiopathy, Down's syndrome, Parkinson-dementia of Guam, hereditary cerebral hemorrhage with amyloidosis-Dutch type and age-related asymptomatic amyloid angiopathy.

Amyloid↗
PubMed1990

Hereditary cerebral haemorrhage with amyloidosis--Dutch type. Magnetic resonance imaging findings in 7 cases.

The clinical history and magnetic resonance imaging (MRI) findings are presented of 7 patients with hereditary cerebral haemorrhage with amyloidosis--Dutch type (HCHWA-D). The diagnosis was based on clinical and genealogical data, was confirmed in 3 patients at autopsy and in 2 others by biopsy. Focal neurological signs, and at least some degree of global cognitive deterioration, were observed in all patients, with unequivocal dementia in 4. MRI showed haemorrhages and areas of gliosis and, to a variable extent, hyperintensity of the white matter in T2-weighted images. Neuropathological examination revealed a large recent haemorrhage together with residual lesions from previous haemorrhages or infarcts in all patients examined. The white matter lesions, present on MRI, turned out to be areas of 'incomplete infarction' with demyelination. It is concluded that (hereditary) amyloid angiopathy can lead to strokes, but also to subcortical ischaemic encephalopathy. Amyloid angiopathy should therefore be considered in the differential diagnosis of white matter lesions, found on CT or MRI, especially when patients present with a cerebral haemorrhage. The relationship between HCHWA-D and Alzheimer's disease, another disease with cerebral amyloid deposition and diffuse white matter involvement, is discussed.

Adult↗