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Biomedical subjects

E L Bollen

Publications and source records attributed to E L Bollen.

At least 19 recordsLinked to original sources
PubMed2002

Testing cognitive function in elderly populations: the PROSPER study. PROspective Study of Pravastatin in the Elderly at Risk.

OBJECTIVES: For large scale follow up studies with non-demented patients in which cognition is an endpoint, there is a need for short, inexpensive, sensitive, and reliable neuropsychological tests that are suitable for repeated measurements. The commonly used Mini-Mental-State-Examination fulfils only the first two requirements. METHODS: In the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER), 5804 elderly subjects aged 70 to 82 years were examined using a learning test (memory), a coding test (general speed), and a short version of the Stroop test (attention). Data presented here were collected at dual baseline, before randomisation for active treatment. RESULTS: The tests proved to be reliable (with test/retest reliabilities ranging from acceptable (r=0.63) to high (r=0.88) and sensitive to detect small differences in subjects from different age categories. All tests showed significant practice effects: performance increased from the first measurement to the first follow up after two weeks. CONCLUSION: Normative data are provided that can be used for one time neuropsychological testing as well as for assessing individual and group change. Methods for analysing cognitive change are proposed.

Aged↗
PubMed2001

[Role of statins in prevention of stroke and dementia].

There is accumulating evidence that statins reduce stroke risk, even though total cholesterol is not a risk factor for stroke. The explanation for this discrepancy is subject to discussion. It should be realised that the beneficial effects of statins on stroke risk have only been demonstrated in a select population, i.e. middle-aged men with ischaemic heart disease. Several clinical trials are underway to examine the effects of statins on stroke risk in more characteristic groups of patients who are at increased risk of developing stroke. The results of these studies should be awaited before statins are recommended for the prevention of stroke. Recently it has been reported that statins lower the risk of developing dementia. These conclusions were drawn from two cross-sectional studies. Because of the nature of the studies, only an association between the use of statins and a lower risk of developing dementia was shown, and not a causal relationship. Experimentally-controlled studies have to be designed to investigate the effect of statins on dementia.

Anticholesteremic Agents↗
PubMed2001

Patients with Alzheimer's disease display a pro-inflammatory phenotype.

BACKGROUND: Inflammation plays a pivotal role in amyloid plaque progression thereby contributing to Alzheimer's disease-related neurodegeneration. We hypothesized that patients with Alzheimer's disease have an innate pro-inflammatory phenotype, as compared to control subjects without dementia. METHODS: Patients with a diagnosis of probable Alzheimer's disease (n=12) and control subjects without signs of dementia (n=18) were enrolled. Whole blood samples were stimulated ex vivo with endotoxin under standard conditions. Cytokine levels were assessed by ELISA and compared by Mann-Whitneyll-test after log transformation. RESULTS: Patients with Alzheimer's disease had seven- to ten-fold higher IL-1beta production relative to the amount of IL-10 both at the low (p=0.006) and high concentration of endotoxin (p=0.007). Subjects who display a pro-inflammatory phenotype as defined by a high IL-1beta/IL-10 ratio had 13.0-fold higher odds (95% CI: 2.1-82) to have dementia. CONCLUSION: The data support the hypothesis that a pro-inflammatory phenotype contributes to the development of Alzheimer's disease.

Aged↗
PubMed2001

Dementia at old age: a clinical end-point of atherosclerotic disease.

The main causes of dementia at old age are Alzheimer's disease and vascular dementia. The clinical presentations of late-onset Alzheimer's disease and vascular dementia can barely be differentiated. This clinical observation is supported by pathological findings. Late-onset dementia should be considered a multifactorial disease, in which both vascular factors and amyloid dispositions contribute to cognitive decline.

Age Factors↗
PubMed2000

Detection of cerebral involvement in patients with active neuropsychiatric systemic lupus erythematosus by the use of volumetric magnetization transfer imaging.

OBJECTIVE: To determine whether volumetric magnetization transfer imaging (MTI) histogram analysis can detect abnormalities in patients with active neuropsychiatric systemic lupus erythematosus (NPSLE) and to compare the MTI findings in patients with active NPSLE, chronic NPSLE, and multiple sclerosis (MS), as well as in normal control subjects. METHODS: Eight female and 1 male patient with active nonthromboembolic NPSLE (mean +/- SD age 39 +/- 9 years), 10 female patients with chronic NPSLE (age 33 +/- 11 years), 10 female patients with SLE and no history of NPSLE (non-NPSLE; age 34 +/- 11 years), 10 female patients with inactive MS (age 41 +/- 6 years), and 10 healthy control subjects (age 33 +/- 11 years) underwent MTL. Using the MTI scans, histograms were composed from which we derived a variety of parameters that quantitatively reflect the uniformity of the brain parenchyma as well as the ratio of cerebrospinal fluid to intracranial volume, which reflects atrophy. RESULTS: The magnetization transfer ratio (MTR) histograms in the non-NPSLE group and the healthy control group were similar, whereas those in the chronic NPSLE and MS groups were flatter. There was also flattening of the histograms in the active NPSLE group, but with a shift toward higher MTRs. CONCLUSION: Our results indicate that volumetric MTI analysis detects cerebral changes in the active phase of NPSLE. The abnormalities in the brain parenchyma of patients with chronic NPSLE produced MTI values that were the same as those in patients with inactive MS. MTI values in the active phase of NPSLE differed from those in the chronic phase, which might reflect the presence of inflammation. These preliminary results suggest that MTI might provide evidence for the presence of active NPSLE. MTI might also prove to be a valuable technique for monitoring treatment trials.

Acute Disease↗
PubMed2000

Innate production of interleukin-10 and tumor necrosis factor affects the risk of multiple sclerosis.

Multiple sclerosis (MS) typically presents with a relapsing-remitting onset. This can be distinguished from primary progressive MS. Typical MS is characterized by a profound inflammatory reaction in which anti-inflammatory cytokine interleukin-10 (IL-10) and pro-inflammatory cytokine tumor necrosis factor (TNF) may play a pivotal role. We tested the hypothesis that patients with MS have a distinct innate cytokine production that contributes to the susceptibility for and outcome of MS. The innate cytokine production of patients was estimated as the average production of cytokines in lipopolysaccharide -stimulated whole-blood cultures of 2 to 5 first-degree healthy family members. A total of 126 family members of 50 patients with typical MS, 61 family members of 25 patients with primary progressive MS, and 129 control subjects of 54 families were enrolled in this study. We found that members of families with low IL-10 and high TNF production had a fourfold increased risk of developing typical MS compared with members of families with high IL-10 and low TNF production. Patients with MS were eightfold more likely to develop typical MS than primary progressive MS when they belonged to families with low IL-10 and high TNF production. The presence of human leukocyte antigen-DR2 was associated with MS but not with TNF production. This study shows that typical MS is associated with an innate pro-inflammatory cytokine profile in contrast to primary progressive MS.

Adult↗
PubMed2000

Interaction of indomethacin with cytokine production in whole blood. Potential mechanism for a brain-protective effect.

Both Alzheimer's disease and vascular dementia are featured by inflammatory responses and it is known that non-steroidal anti-inflammatory drugs (NSAIDs) decrease the risk and severity of these diseases. To study the effect of NSAIDs on PGE2 levels and pro- and anti-inflammatory cytokine levels in the whole blood assay, blood samples from 23 elderly persons aged 85 years were stimulated with thrombin or LPS as primary stimulus. Indomethacin was added in concentrations ranging from 0.4 to 16 microg/ml and acetylsalicylic acid was added to in concentrations ranging from 0.5 to 8.0 microg/ml. Indomethacin abrogated thrombin- and LPS-induced PGE2 production at all concentrations tested. In addition, indomethacin reduced the production of thrombin-induced IL-6 and IL-10 (p<0.05) at physiological concentrations. Indomethacin reduced the production of LPS-induced IL-6, IL-1 beta and IL-10 (p<0.05) at the highest indomethacin concentration tested. Similar results were obtained upon incubation with acetylsalicylic acid. It is concluded that indomethacin may reduce the thrombin-induced inflammatory reaction by decreasing IL-6 through inhibition of PGE2 synthesis. This IL-6 reduction may be relevant for the ability of indomethacin to reduce the risk of Alzheimer's disease. However, the decrease in IL-10 production due to indomethacin suggests a more inflammatory state.

Aged↗
PubMed2000

HMG-CoA reductase inhibitors in the prevention of stroke.

Stroke is a heterogeneous disorder, with the definition including both haemorrhagic and ischaemic stroke. Although these subtypes of stroke have different underlying pathophysiological mechanisms, atherosclerosis plays a pivotal role in both. Most risk factors for cardiovascular disease are also risk factors for stroke. Patients with a history of cardiovascular events are at an increased risk of stroke. Although hypercholesterolaemia is the most characteristic risk factor for atherosclerotic diseases, recent data suggest that the correlation between cholesterol levels and either ischaemic or haemorrhagic stroke is weak. However, the interpretation of these results is hampered by the inconsistent use of classifications of the various subtypes of stroke in studies. Pooled data on the effect of HMG-CoA reductase inhibitors show a 30% risk reduction in strokes. These beneficial effects are obtained from studies in middle aged patients with ischaemic heart disease, the interpretation being that the effects of HMG-CoA reductase inhibitors on stroke are mediated via (i) cholesterol-lowering effects on the coronary vasculature or (ii) cholesterol-independent effects of these agents. The results cannot be extrapolated to the elderly, among whom stroke most frequently occurs.

Cholesterol↗
PubMed1999

The design of a prospective study of Pravastatin in the Elderly at Risk (PROSPER). PROSPER Study Group. PROspective Study of Pravastatin in the Elderly at Risk.

The PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) is a randomized, double-blind, placebo-controlled trial designed to test the hypothesis that treatment with pravastatin will diminish risk of subsequent major vascular events in a cohort of men and women (70 to 82 years old) with preexisting vascular disease or significant risk of developing this condition. Five thousand eight hundred four men and women in addition to receiving advice on diet and smoking, have been randomized equally to treatment with 40 mg pravastatin/day or matching placebo in 3 centers (Cork, Ireland, Glasgow, Scotland, and Leiden, The Netherlands). Following an average 3.5-year intervention period, a primary assessment will be made of the influence of this therapy on major vascular events (a combination of coronary heart disease, death, nonfatal myocardial infarction, and fatal and nonfatal stroke). A number of additional analyses will also be conducted on the individual components of the primary end point, on men, on women, and on subjects with and without previous evidence of vascular disease. Finally, an assessment will be made of the effects of treatment on cognitive function, disability, hospitalization or institutionalization, vascular mortality, and all-cause mortality.

Aged↗
PubMed1999

Pathophysiology of chorea and bradykinesia in Huntington's disease.

This article reviews the neurophysiological abnormalities described in Huntington's disease. Among the typical features of choreic movements are variable and random patterns of electromyographic (EMG) activity, including cocontraction of agonist and antagonist muscles. Studies of premotor potentials show that choreic movements are not preceded by a Bereitschaftspotential, therefore demonstrating that choreic movement is involuntary. Early cortical median-nerve somatosensory-evoked potentials have reduced amplitudes and the reduction correlates with reduced glucose consumption in the caudate nucleus. Long-latency stretch reflexes evoked in the small hand muscles are depressed. These findings may reflect failed thalamocortical relay of sensory information. In Huntington's disease, the R2 response of the blink reflex has prolonged latencies, diminished amplitudes, and greater habituation than normal. These abnormalities correlate with the severity of chorea in the face. Patients with Huntington's disease perform simple voluntary movements more slowly than normal subjects and with an abnormal triphasic EMG pattern. Bradykinesia is also present during their performance of simultaneous and sequential movements. Eye movements show abnormalities similar to those seen in arm movements. In Huntington's disease, arm movement execution is associated with reduced PET activation of cortical frontal areas. Studies using transcranial magnetic stimulation show that patients with Huntington's disease have normal corticospinal conduction but some patients have a prolonged cortical silent period. Bradykinesia results from degeneration of the basal ganglia output to the supplementary motor areas concerned with the initiation and maintenance of sequential movements. The coexisting hyperkinetic and hypokinetic movement disorders in patients with Huntington's disease probably reflect the involvement of direct and indirect pathways in the basal ganglia-thalamus-cortical motor circuit.

Basal Ganglia↗
PubMed1997

Central nervous system relapse in non-Hodgkin lymphoma. A single-center study of 532 patients.

OBJECTIVES: To define the cumulative risk of central nervous system (CNS) relapse in systemic non-Hodgkin lymphoma (NHL); to assess the risk factors of age, sex, malignancy grade, stage, localization, and response to initial therapy; and to evaluate the effect of CNS prophylaxis. PATIENTS AND METHODS: An unselected group of 532 patients with systemic NHL. A retrospective analysis. RESULTS: Eleven patients presented with systemic as well as CNS localization, whereas in 55 patients, CNS relapse occurred later. The cumulative risk of CNS relapse at 4 years for all 532 patients was 19%. High-grade NHL carried a 39% risk of CNS relapse, with the vast majority of relapses occurring in the first 14 months after the initial diagnosis. The cumulative risk in patients with intermediate-grade NHL was considerable (22%) and dispersed throughout a much longer period (6 years). Patients with low-grade NHL still carried a 7% risk of CNS relapse; in all these patients, low malignancy grade was transformed into a higher malignancy grade at that time. In a multivariate analysis, high- and intermediate-grade NHL and advanced stage were independent risk factors for CNS relapse. There was not any strong evidence for a beneficial role of CNS prophylaxis in patients with intermediate- and high-grade NHL, but a retrospective analysis cannot be conclusive with regard to the effect of therapy. Systemic relapse occurred rapidly after CNS relapse, resulting in a median survival time after CNS relapse of only 2 months. CONCLUSIONS: Patients with high- and intermediate-grade NHL carry a considerable risk of CNS relapse. Advanced stage is an additional independent risk factor. The role of CNS prophylaxis seems to be disappointing, but a retrospective analysis cannot be conclusive. Prognosis after CNS relapse is poor.

Adolescent↗
PubMed1997

TNF-alpha promoter polymorphisms, production and susceptibility to multiple sclerosis in different groups of patients.

TNF-alpha production in whole blood cultures upon stimulation with LPS was determined in 179 individuals from 61 families in order to characterise the magnitude of inherited differences in TNF-alpha production. The three families characterised by highest TNF production showed 7.1 +/- 0.3 ng TNF/ml upon culture with 10 ng LPS and 10.2 +/- 0.2 ng TNF/ml upon culture with 1000 ng LPS. in contrast to the three families characterised by the lowest TNF production that showed a production of 1.6 +/- 0.1 ng TNF upon culture with 10 ng and 2.5 +/- 0.2 ng/ml upon culture with 1000 ng LPS/ml. This difference could not be attributed to the promoter polymorphisms -308 G to A. -238 G to A or -376 G to A, although the -238 GA donors produced 2.1 +/- 0.9 ng TNF upon culture with 10 ng endotoxin compared to 3.2 +/- 2.2 ng TNF for the -238 GG donors. In line with these results the frequency of the -238 GG genotype was increased in hospitalized MS patients in a nursing home (100% 238GG, n = 57) compared to MS patients in an outpatient's clinic (94% 238GG, n = 98) or Dutch controls (90% 238GG, n = 180). These results suggest that the -238 GG genotype is differently distributed in hospitalized MS patients in a nursing home.

Disease Susceptibility↗
PubMed1997

High intensity of oral anticoagulant therapy in patients with cerebral haemorrhage: cause or consequence of the bleeding?

In assessing the optimal intensity of anticoagulant therapy, the International Normalized Ratio (INR) at admission is used as a basis for INR-specific incidence rates. In 47 patients suffering a haemorrhagic stroke we tested the assumption that the INR at admission is an acceptable measure for the INR that preceded the haemorrhage. We found high D-dimer levels in 70% of the patients, which indicated activated coagulation and fibrinolysis. This was not of such an extent that it could also be measured with other routine coagulation tests, with the possible exception of two patients. We found normal INRs in 33 non-anticoagulated patients, and only a mildly prolonged INR of 1.9 in one patient, which was most probably caused by a vitamin K deficiency. We concluded that the INR at admission can be used in studies to assess the optimal level of anticoagulation.

Administration, Oral↗
PubMed1991

[No difference in efficacy of hydroquinine and placebo in restless legs syndrome].

OBJECTIVE: Determination of the efficacy of hydroquinine treatment of the restless legs syndrome. DESIGN: Double blind cross-over trial. SETTING: University Hospital Leiden. PATIENTS AND METHODS: Selection through an announcement in the press and followed by structured interview. Inclusion criteria according to the international classification of sleep disorders. Exclusion criteria defined by medication risks. Patients used either hydroquinine (200 mg in the evening and 200 mg before going to bed) or placebo in the second and fourth of four periods of two weeks duration. Severity of complaints was assessed using a daily questionnaire and a Suggested Immobilization Test (SIT) twice weekly, in which they noted the severity of complaints as experienced during a 15-minute period of immobilization. RESULTS: The study was completed by 59 out of 68 patients. Analysis of variance showed no significant differences between the two groups of patients (those starting with placebo and those starting with hydroquinine) for any of the questions of the daily questionnaire or of the SIT. McNemar's test showed no significant differences between the proportions of patients who wished to continue the use of either placebo or hydroquinine. CONCLUSION: This study showed no significant differences between the efficacy of placebo or hydroquinine in the restless legs syndrome.

Adult↗
PubMed1991

Nerve conduction velocity to different muscles in peroneal pressure neuropathy.

The variability inherent in nerve conduction velocity (NCV) studies suggests that multiple measurements may yield more information than a single measurement. To test this hypothesis, three motor nerve conduction velocities (NCVs) of the peroneal nerve were measured: to the extensor digitorum brevis muscle over the fibular head and in the lower leg, and to the tibialis anterior muscle over the fibular head. Three groups were studied: controls, polyneuropathy cases and peroneal pressure neuropathy cases. Over the fibular head, NCVs recorded from the tibialis anterior were consistently higher than those from the extensor digitorum brevis, and showed a higher number of abnormalities. Differences between NCVs, their Z-scores and Mahalanobis distances were compared to study the influence of variance differences and covariances. The best compromise between true and false positives was found to be a comparison between NCVs over the fibular head recorded from the tibialis anterior and the leg segment recorded from the extensor digitorum muscle. Z-scores are more useful than Mahalanobis distances in this respect.

Adult↗