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P Arlien-Søborg

Publications and source records attributed to P Arlien-Søborg.

At least 19 recordsLinked to original sources
PubMed2003

Axonal recovery after severe traumatic brain injury demonstrated in vivo by 1H MR spectroscopy.

Proton magnetic resonance spectroscopy (MRS) suggested almost complete axonal recovery 21 months after trauma in a patient with severe diffuse axonal injury. MRS while the patient was comatose showed evidence of severe diffuse axonal injury in occipitoparietal white matter, but occipital grey matter was relatively spared. At 21 months N-acetylaspartate was normal. At 33 months examination showed a Functional Independence Measure of 83 and a Rancho Los Amigos Scale of Cognitive Function of 7-8, a remarkable improvement considering all the initial findings, except those of MRS.

Adult↗
PubMed2000

Neurotoxic interactions of industrially used ketones.

Occupationally workers are most often exposed to a mixture of solvents. Exposure limits are, however, usually set separately for single solvents. So we reviewed the present knowledge about possible neurotoxic interactions of the industrially most used ketones acetone (ACE), methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK) with solvents in general. A literature search from the last 25 years (1974-1998) revealed 54 original publications describing neurotoxic monitoring after combined exposure (experimental and occupational) involving the mentioned ketones. Animal exposure was described in 27 reports, exposure involving human volunteers in 12 reports, and occupational surveys constituted 15 reports. Of the 54 papers, 25 dealt with potentiation by ACE, MEK or MIBK of n-hexane or 2,5-hexanedione (2,5-HD) induced neurotoxicity. Possible synergistic interactions of the ketones were reported in 12 of the 29 remaining works. Only two studies reported neurotoxic potentiation after acute short-term combined exposure to human volunteers. Possible neurotoxic potentiation by the ketones after occupational mixed exposure without the involvement of n-hexane or 2,5-HD, were reported in 8 papers. Some studies reported a different outcome of metabolic interactions based on animal or volunteer exposure, compared to more long-term occupational exposure. We conclude that the widespread use of the rule of additivity often underestimates the effect when dealing with combined exposure to industrially used ketones. We also conclude that the results of combined exposure obtained in animals or human volunteers cannot necessarily be extrapolated to occupational situations. More research is needed in particular concerning the most frequently occurring mixtures comprising ketones and aromatic solvents such as acetone (ACE) and styrene as well as methyl isobutyl ketone (MIBK) and toluene.

Acetone↗
PubMed1999

[Cerebral dysfunction occurring after years of latency].

A number of basically very different factors may affect the central nervous system and result in progressive loss of mental or physical functions immediately or after a latent period of decades, possibly due to the initial factor being combined with an additive effect of aging. Intoxication with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induces degeneration of the basal ganglia. Various vira e.g. poliovirus and retrovirus may give rise to acute or late effects after several years. The Concentration Camp Syndrome may lead to a dementing illness with a latency of 10-30 years. Signs of progressive degenerative CNS disease should give rise to considerations of possible provoking factors earlier in the patient's life history.

Brain↗
PubMed1999

LDL receptor mutations and ApoB mutations are not risk factors for ischemic cerebrovascular disease of the young, but lipids and lipoproteins are.

BACKGROUND: The genetic background for ischemic cerebrovascular disease of the young and the role of lipids and lipoproteins as risk factors are not clear. METHODS: We determined five LDL receptor mutations (Trp23Stop, Trp66Gly, Trp556Ser, 313+1G --> A, 1846-1G --> A) and three apolipoprotein B mutations (Arg3500Gln, Arg3500Trp, Arg3531Cys), and other risk factors for ischemic cerebrovascular disease in 80 patients (36 women, 44 men) with onset of disease before the age of 50 years compared with 3366 individuals from a general population sample within the same age range. RESULTS: None of the patients were carriers of mutations in the LDL receptor (Trp23Stop, Trp66Gly, Trp556Ser, 313+1G --> A, 1846 - 1G --> A) or the apolipoprotein B gene (Arg3500Gln, Arg3500Trp, Arg3531Cys) associated with hypercholesterolemia. However, on univariate analysis as well as on logistic regression analysis allowing for age and gender, plasma cholesterol (OR 1.4; P < 0.0005), HDL-cholesterol (OR 0.4; P < 0.005), diabetes (OR 5.8; P < 0.0001), and hypertension (OR 3.9; P < 0.001) were significant predictors of ischemic cerebrovascular disease. CONCLUSIONS: The five most common LDL receptor mutations in Danish patients with familial hypercholesterolemia and three mutations in the apolipoprotein B gene did not predispose to ischemic cerebrovascular disease of the young. However, cholesterol and HDL-cholesterol are important risk factors for ischemic cerebrovascular disease of the young in the present study. The elevation in cholesterol could in some patients be due to rare LDL receptor mutations not tested for, and could in other patients be multifactorial in origin.

Adult↗
PubMed1998

A new mitochondrial tRNA(Met) gene mutation in a patient with dystrophic muscle and exercise intolerance.

A 30-year-old woman with a novel heteroplasmic U4409C mtDNA mutation in the tRNA(Met) gene presented with growth retardation, muscle weakness, severe exercise intolerance, and lactic acidosis. Muscle biopsy showed unusually severe dystrophic features. The mutation was not present in maternal relatives or 25 healthy subjects. Single-fiber PCR-RFLP analysis of mtDNA showed higher proportion of the mutation in COX-negative than in COX-positive muscle fibers.

Adult↗
PubMed1996

Neuronal loss in hippocampus in rats exposed to toluene.

Both clinical and epidemiological studies of the effects of exposure to toluene have shown that long-term exposure may result in chronic toxic encephalopathy, where one of the major symptoms is memory deficits. We have attempted to identify the structural basis of the toxic effects of toluene in the hippocampus, a region of the brain known to be involved in learning and memory processes and well suited for stereological analysis. Rats were exposed to 1500 ppm of toluene, six hours per day, five days per week for six months. This was followed by a four-month-period without exposure prior to sacrifice. The total number of neurons in each of the five subdivisions of hippocampus of six exposed and six control rats was estimated with the optical fractionator. A statistically significant neuron loss of 16% was found in regio inferior (CA3 and CA2) of the exposed rats.

Animals↗
PubMed1995

Cognitive function and anticonvulsant therapy: effect of monotherapy in epilepsy.

INTRODUCTION: The effect of antiepileptic drugs (AED) on cognitive function was studied in 87 patients with epilepsy. MATERIAL AND METHODS: Group A: (n = 52) started AED treatment (carbamazepine, oxcarbazepine, sodium-valproate, phenobarbital or phenytoin). Group B: (n = 27) had AED monotherapy withdrawn (carbamazepine or sodium-valproate). Group C: (n = 8) was switched from phenytoin to carbamazepine monotherapy. The patients were tested before and 4 months after change of the treatment. RESULTS: In group A the test performances were in general unchanged. Patients who had their drug treatment withdrawn (group B) and the patients who were switched from phenytoin to carbamazepine (group C) improved in single tests. The predominant changes in performance seem to be due to practice effect. CONCLUSION: Cognitive functions are only minimally influenced by AEDs after short-term treatment whereas there is a slight improvement after discontinuation of long-term administration of carbamazepine and valproate. A lack of practice effect might be the first indicator of a negative effect of AED on cognitive function.

Adolescent↗
PubMed1994

Long-term follow-up of cerebral infarction patients with proton magnetic resonance spectroscopy.

BACKGROUND AND PURPOSE: With proton magnetic resonance spectroscopy it is possible to measure the content of various brain metabolites in vivo, including N-acetylaspartate (which may be used as a neuronal marker), creatine, choline, and lactate. The content of these brain metabolites was measured serially from the acute stage to the chronic stage of infarction. Regional cerebral blood flow was also measured within the affected areas. These factors were compared with the clinical outcome. METHODS: Six patients with ischemic stroke were examined serially from the acute stage (< or = 2 days) to the chronic stage (> 6 months) with proton magnetic resonance spectroscopy. Cerebral blood flow was measured with single-photon emission-computed tomography with 99mTc-labeled d,l-hexamethylenepropyleneamine oxime as flow tracer. RESULTS: Lactate was found in all patients in the acute stage of stroke. Lactate was also found in the 3 largest lesions in the chronic stage; in 2 of these patients lactate was not found in the subacute stage. Reduced levels of N-acetylaspartate were found in 5 patients; in the sixth patient with a small lesion no reduction was found. In all lesions reduced blood flow was found in the acute and chronic stage, whereas hyperemia was found in 4 patients in the subacute stage. CONCLUSIONS: In this preliminary study no clear correlation was found between the level of N-acetylaspartate or lactate in the acute stage of stroke and the clinical outcome; however, there does appear to be some connection between the reduction of cerebral blood flow and the spectroscopic findings in the chronic stage and to some extent the clinical outcome. Studies of larger clinical groups will be necessary to further elucidate the prognostic potential of proton magnetic resonance spectroscopy in human stroke.

Adult↗
PubMed1993

[Magnetic resonance spectroscopy of acute cerebral infarctions].

Eight patients with brain infarction were examined serially in the acute phase and one week and two to four weeks after stroke with water-suppressed proton magnetic resonance spectroscopy. Ten healthy volunteers served as controls. The time courses of N-acetylaspartate (NAA), total creatine (Cr), choline containing compounds (Cho), lactate content, and regional cerebral blood flow (rCBF) measured by SPECT were studied. A high lactate level was found in the acute phase. The lactate content decreased to barely detectable levels during the following two to four weeks, while rCBF increased during this period. The content of NAA in infarcted tissue was significantly reduced (p < 0.01) compared to healthy controls, Cr was also reduced (p < 0.02), whereas Cho content did not change. The inverse relationship between lactate level and cerebral blood flow suggests that lactate plays no substantial role in the vasodilatation underlying the hyperaemia that follows reperfusion. The amount of lactate present in the acute phase reflects the severity of ischaemia in the affected region. The content of NAA may be used as a neuronal marker, and thus perhaps as a marker of the effect of future treatment procedures.

Acute Disease↗
PubMed1993

Myelography, CT, and MRI of the spinal canal in patients with myelopathy: a prospective study.

A prospective study including myelography, CT, and MRI was performed on 36 patients with clinical signs of myelopathy. Evoked potentials and spinal fluid examinations were also carried out. Based on our findings, the patients could be classified as suffering from cryptogenic myelopathy (n = 12), multiple sclerosis (n = 6), spinal stenosis (n = 6), or miscellaneous myelopathies (n = 12). The diameter of the spinal cord was normal in the 2 first groups of patients and of same magnitude evaluated by myelography and CT, while MRI constantly gave higher figures. In only four of the patients important new information was added by CT and MRI (syringomyelia, myelitis, lipomatosis) compared with myelography, although a more precise visualization was often provided. Further diagnostic progress in patients with myelopathy of undetermined etiology may be obtained by including supplementary MRI of the brain disclosing multiple sclerosis in several cases.

Adult↗
PubMed1993

Clinical neurological findings among metal degreasers exposed to chlorinated solvents.

Among industrial solvents in present use trichloroethylene belongs to those which have been the concern of most neurological and occupational investigations since the beginning of this century. Reports on a broad spectrum of neurotoxicity are however mostly based on case-studies and accidental circumstances. The object of this study was to examine clinical neurological manifestations after long-term exposure to degreasing solvents, mainly trichloroethylene. The population was 99 metal degreasers, the design a historical cohort study. The most marked finding was a highly significant dose-response relation between solvent exposure and motor dyscoordination--a finding that was retained after multivariate control of relevant confounders. Vibration thresholds increased by solvent exposure at bivariate level, but the multivariate analysis showed that age was explaining most of the increase. No significant cranial nerve dysfunction was found.

Cohort Studies↗
PubMed1993

Brain autopsy in organic solvent syndrome.

General autopsy findings, brain weight and brain pathology were studied in 98 men and five women who had been exposed occupationally to organic solvents over several years and assessed by the Danish National Board of Industrial Injuries for chronic toxic encephalopathy. The findings were compared with a forensic control material and a hospital control material. As in the general population, the most common causes of death among the exposed workers were heart failure and other vascular diseases. Due to the composition of the material (forensic cases), the number of suicides and violent deaths was high. Atherosclerosis was the most common CNS finding, but in comparison with the two control materials, no increase in the frequency of atherosclerosis or of Alzheimer's disease was found. Brain weights of the exposed workers corresponded closely to brain weights in the control materials, after correction for body height, body weight and age. Chronic alcoholism was correlated with slightly reduced brain weight.

Adult↗
PubMed1993

Effects of six months' white spirit inhalation exposure in adult and old rats.

In two separate experiments in rats the irreversible effects of six months' exposure to white spirit (0, 400 p.p.m., and 800 p.p.m.) were studied. In one experiment the exposure started at the age of three months, in the other the rats were 15 months at the beginning of the exposure. After an exposure-free period of several months neurobehavioural, pathological, and neurochemical examinations were performed. A marked difference in motor activity between young and aged animals was found. A slight effect on kidney function was seen at 800 p.p.m. No macroscopic or histopathological changes related to dosing were found. The concentrations of noradrenaline, dopamine, and 5-hydroxytryptamine in various brain regions and in whole brain were irreversibly changed. In conclusion, the study revealed different changes within the CNS, but failed to demonstrate neurobehavioural white spirit-induced neurotoxicity.

Administration, Inhalation↗
PubMed1993

Thrombolytic therapy in acute ischemic stroke. A Danish pilot study.

BACKGROUND AND PURPOSE: In a feasibility and safety study of thrombolytic therapy in acute ischemic stroke, we explored the usefulness of measurements of regional cerebral blood flow. METHODS: Twenty-three patients with acute ischemic stroke were treated with 100 mg recombinant tissue plasminogen activator infused intravenously over 1 hour. Thrombolytic therapy was initiated 78 to 355 minutes after onset of symptoms. RESULTS: Angiography 16 to 24 hours after treatment in 17 patients showed patient intracranial arteries in 12, partial occlusion of the middle cerebral artery in 3, and total occlusion of the middle cerebral artery in 2. rCBF with 99mTc-hexamethylpropyleneamine oxime intravenously was measured 5 minutes before and within 24 hours after thrombolytic therapy in 12 patients. 10 of the 12 patients showed brain tissue reperfusion and 2, with angiographically documented middle cerebral artery occlusion, showed no reperfusion, thus documenting a relationship between reperfusion measured by regional cerebral blood flow and angiographic patency (P = .015). Three patients died. Patients who were reperfused within 24 hours (documented by repeated regional cerebral blood flow measurements) showed greater clinical improvement on the Scandinavian Stroke Scale the sooner their thrombolytic therapy was started and the more severe their neurological deficits. CONCLUSIONS: Acute cerebral ischemia can be documented by rCBF measurements without delay of thrombolytic therapy, and repeated rCBF measurements can reveal whether cerebral reperfusion has occurred. In our study, early reperfusion was associated with clinical improvement.

Adult↗
PubMed1992

Early time course of N-acetylaspartate, creatine and phosphocreatine, and compounds containing choline in the brain after acute stroke. A proton magnetic resonance spectroscopy study.

BACKGROUND AND PURPOSE: The early time course after acute stroke of cerebral N-acetylaspartate, creatine and phosphocreatine, and compounds containing choline was studied in vivo by means of localized water-suppressed proton magnetic resonance spectroscopy. METHODS: Eight patients with acute stroke were studied serially in the acute phase, 1 week after, and 2-4 weeks after the onset of clinical symptoms. Ten healthy volunteers served as controls. A stimulated echo (STEAM) sequence was used for measurement of the brain metabolites in a volume of interest located within the infarcted area as visualized by magnetic resonance imaging. For quantification, the unsaturated water signal was used as the internal standard. Regional cerebral blood flow in the infarcted area was measured relative to a symmetrically located unaffected area by means of single-photon emission computed tomographic scanning, using 99mTc-labeled d,l-hexamethylenepropyleneamine oxime as the flow tracer. RESULTS: Relative regional cerebral blood flow was considerably reduced in the infarcted area in the acute phase. After 1 week, hyperemia was seen in all but one patient. The N-acetylaspartate content was significantly reduced, with the loss appearing to occur between 6 and 24 hours after the stroke incident. The reduction in N-acetylaspartate content was greater in the central part than in the peripheral part of the infarcted area. Creatine and phosphocreatine were also reduced in the infarcted area, whereas no significant change was seen in the choline content. CONCLUSIONS: Assuming that N-acetylaspartate content reflects neuronal survival or loss, our results may suggest that treatment procedures with restoration of blood flow to severely ischemic areas should be initiated within the first 6 hours after stroke onset.

Acute Disease↗
PubMed1991

Irreversible effects in rats of toluene (inhalation) exposure for six months.

The irreversible CNS effects of six months' exposure to toluene (0, 500, and 1500 p.p.m.) in rats was studied applying a multi-disciplinary approach. After an exposure-free period, neurobehavioural, morphometric, pathological, and biochemical examinations were performed. No neurobehavioural or gross pathological changes were found. Morphometric measurements did not show loss of neurones. At 500 p.p.m. the mean nuclear volume and mean perikaryonal volume and the variation of the values of these parameters was increased in the exposed groups compared to the controls. Noradrenaline (NA), dopamine (DA), and 5-hydroxytryptamine (5-HT) levels were significantly changed in various brain regions. It is concluded that this investigation failed to reveal overt toluene-induced CNS-neurotoxicity, however, certain irreversible effects were found which further add to the accumulating evidence of the chronic CNS-neurotoxicity of toluene.

Administration, Inhalation↗