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Biomedical subjects

A M Dam

Publications and source records attributed to A M Dam.

14 recordsLinked to original sources
PubMed2002

In vitro cell irradiation systems based on 210Po alpha source: construction and characterisation.

One way of studying the risk to human health of low-level radiation exposure is to make biological experiments on living cell cultures. Two 210Po alpha-particle emitting devices, with 0.5 and 100 MBq activity, were designed and constructed to perform such experiments irradiating monolayers of cells. Estimates of dose rate at the cell surface were obtained from measurements by a PIPS alpha-particle spectrometer and from calculations by the SRIM 2000, Monte Carlo charged particle transport code. Particle fluence area distributions were measured by solid state nuclear track detectors. The design and dosimetric characterisation of the devices are discussed.

Alpha Particles↗
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 Group B: (n = 27) had AED monotherapy withdrawn (carbamazepine or sodium-valproate).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 Patients who had their drug treatment withdrawn (group B) and the patients who were switched from phenytoin to carbamazepine (group C) improved in single tests.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↗
PubMed1992

Estimation of the total number of neurons in different brain areas in the Mongolian gerbil: a model of experimental ischemia.

The quantitative stereological method is applied to a study of the number of neurons in three different areas in the brains of an animal model, the Mongolian gerbil. The simplicity and accuracy of the method is emphasized. The usefulness of the method and the model is mentioned especially focusing on the major disabling disease in the Western world today, cerebrovascular disorders. Some results are presented to give an idea of the maximum number of neurons in these animals within the delineation of the brain areas here applied.

Animals↗
PubMed1990

Neuropathology of epilepsy.

The neuropathology of symptomatic and idiopathic epilepsy is presented. New methods of investigation have disclosed that more cases of epilepsy are symptomatic--even hippocampal sclerosis is now detectable in vivo by MR-scan. It still remains to be defined whether hippocampal sclerosis is the cause or the effect of epilepsy. The present survey focusses upon the delineation of hippocampal neuron loss with a critical discussion of various hypotheses drawn from various human and experimental studies. In particular the phenomenon of selective and delayed neuron loss are explored with regard to future neurosurgical approaches.

Animals↗
PubMed1984

Does seizure activity produce Purkinje cell loss?

Eight Wistar rats were exposed to 140 electroconvulsive seizures over 50 days. Ten rats served as controls. The density of Purkinje cells in cerebellum ranged from 15.3 to 18.5/mm in the treated rats and from 15.2 to 19.1/mm in the controls. No Purkinje cell loss was disclosed in the rats subjected to electroconvulsive seizures. Twenty-five Mongolian gerbils of the seizure-susceptible strain were selected according to seizure score with five animals in each group. Five Mongolian gerbils of a seizure-resistant strain served as controls. The density of the Purkinje cells ranged from 21.4 to 29.8/mm in the seizure-susceptible animals and from 27.6 to 31.5/mm in the controls, with a lower density in the gerbils with seizures compared with the controls (p less than 0.05). There was no relation to type or number of seizures. Eight gerbils of the seizure-susceptible strain were included as a supplementary group, to disclose any possible genetic trait as an explanation of the lower Purkinje cell density. The Purkinje cell density in these animals ranged from 24.8 to 30.9/mm and did not differ from the density in the seizure-resistant gerbils. Thus the lower density of Purkinje cells in the seizure-susceptible Mongolian gerbils is a result of seizure activity. The excessive epileptic input with stimulation of the glutamatergic innervation of the Purkinje cells resulting in a persistent elevated gamma-aminobutyric acid (GABA) tone may explain the damage to the Purkinje cells in the gerbils and the loss of Purkinje cells found in patients with severe epilepsy.

Animals↗
PubMed1980

Epilepsy and neuron loss in the hippocampus.

Quantitation of hippocampal neurons was performed in 20 patients with generalized epilepsy. Twelve suffered from partial seizures. The neuronal numbers were compared with the control series of patients without epilepsy. It was established that there were fewer neurons in the hippocampi from patients with epilepsy than from those of controls. The neuron loss was particularly marked in the endfolium (field H3), the granule cells (fascia dentata), and particularly in the caudal (anterior) part of the structure. Frequent, generalized epileptic seizures and long duration of the epileptic disorder influenced the neuron loss. In some parts of the pyramidal band (field H1), the neuron loss appeared at a younger age, which leads one to suspect its particular involvement in the seizure mechanism. The neuron loss was not related to the different types of seizures investigated. The results support the hypothesis of neuron loss as an ongoing process in patients with epilepsy, whatever the type of epilepsy, when tonic-clonic seizures, as is very common, are present.

Adult↗
PubMed1979

Carbamazepine vs phenytoin. A controlled clinical trial in focal motor and generalized epilepsy.

The antiepileptic effects of carbamazepine and phenytoin were compared in a double-blind crossover trial studying patients with primary and secondary generalized seizures and partial seizures with motor symptoms. Each treatment period lasted ten weeks. The patients were seen every two weeks, and doses were adjusted according to plasma levels. It was attempted to keep levels in the optimal plasma range, ie, 10 to 20 and 4 to 10 mg/liter for phenytoin and carbamazepine, respectively. Twenty-three patients entered and 19 completed the study. No statistically significant differences were found between carbamazepine and phenytoin with regard to seizure control and acute side effects.

Adolescent↗
PubMed1976

Neurological disorders and detrusor hyperreflexia.

In 152 consecutively selected patients with detrusor hyperreflexia (DH) 96 (63 per cent) had neurological disorders. Thirty-two patients did not show any primary neurological or urological cause for DH. This group was chosen to elucidate the evaluation of possible neurological symptoms in relation to the urological symptomatology. Nine had died and one failed to appear to the neurological examination. Twelve (63 per cent) of the 22 examined patients showed signs of lesions in different parts of the central nervous system, particularly cerebrovascular diseases and myeloneuropathy. Six had had neurological symptoms for years. In two the urological symptoms were first to appear. In the group with no neurological complaints the urological symptoms had existed for 2-30 years. No essential difference was found in the degree of voiding disturbance whether or not neurological signs were disclosed. It is concluded that the discovery of DH should be followed by a neurological examination to disclose further signs of lesions in CNS. Likewise, an extended urological examination with demonstration of DH might help in the evaluation of an obscure neurological disease.

Adolescent↗
PubMedDate not supplied

Late-onset epilepsy: etiologies, types of seizure, and value of clinical investigation, EEG, and computerized tomography scan.

Approximately 25% of patients with epilepsy will have their first seizure after the age of 25 years. These individuals will need special attention with regard to etiology. Brain tumor is one of several causes that may be suspected. The present study of 221 patients with late-onset epilepsy from the University Clinic of Neurology, Hvidovre Hospital, Copenhagen, Denmark, was undertaken to look for means to select those cases in which computerized tomography (CT) scan should be performed. Brain tumor was the cause in 16% and cerebrovascular infarctions in 14%. The major etiological group was the one in which no cause could be detected (38%). Alcohol abuse as the etiology--defined as cases with a history of long-standing alcohol overuse, concomitant signs of alcohol intoxication, and spontaneous recurrent epileptic seizures--made up a group of one-fourth of all the patients with late-onset epilepsy. Comparison of the history, clinical symptoms and signs, EEG abnormalities, and CT scan speaks in favor of some consideration being given to the first three parameters before the CT scan is performed.

Adult↗