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Biomedical subjects

R Dreyer

Publications and source records attributed to R Dreyer.

At least 73 records · Page 4Linked to original sources
PubMed1981

Use of periodate and methylamine for the quantitation of intracellular 5-fluoro-2'-deoxyuridine-5'-monophosphate by high-performance liquid chromatography.

High-performance liquid chromatography was used for the quantitation of [3H]fluorouracil and metabolites in L1210 cells with or without pre-treatment with methotrexate. Ribonucleotide pools were evaluated on a chemically bonded anion-exchange column. Deoxynucleotide pools were determined following periodate and methylamine treatment which eliminated the ribonucleotides (greater than 99.9% complete) and allowed for a rapid quantitation of the acid-soluble 5-fluoro-2'-deoxyuridine-5'-monophosphate (FdUMP) pools. FdUMP levels as low as 10 fmol/10(6) cells were detectable by polystyrene anion-exchange chromatography. Confirmation of these FdUMP values was performed by rechromatography on a reversed-phase ion-pair column. The use of periodate and methylamine as a means for the reliable elimination of the ribonucleotides will allow accurate isolation of deoxynucleotides by high-performance liquid chromatography.

Animals↗
PubMed1978

[The symptom of EEG-flattening accompanying psychomotor attacks, their frequency, duration, form and significance. A video-band analysis of 78 patients with 187 attacks (author's transl)].

A total of 187 psychomotor attacks in 78 epileptic patients were recorded on video band; 48 patients (61.5%) and 100 attacks (55.5%) showed signs of EEG flattening. This flattening became manifest before the clinical onset of the fit in 11.88% of patients, simultaneously with the fit in 30.5%, during the fit in 17.1%, and at the end of the attack in 4.8%. In 10.7% of the attacks, the flattening was considered as a cardinal EEG symptom of the fit, since it lasted longer than two-thirds of attack duration. Side differences in flattening occurred only in 6.4% of all attacks. The constancy of flattening varied in patients who had several attacks. Only few cases showed consistent flattening. In 50% of attacks with a remembered aura, the flattening occurred before the clinical signs of the fit. Since EEG flattening is explained by an arousal activation of the ascending reticular formation, it is assumed that the epileptic discharge of the psychomotor attack is initiated by activation of the nonspecific ascending reticular and limbic systems. This results in EEG flattening and clinically in an unconsciousness reaction.

Adolescent↗
PubMed1978

[Laughing in complex partial seizure epilepsy. A video tape analysis of 32 patients with laughing as symptom of an attack (author's transl)].

According to videotape analysis, laughter is a frequent (42.7%) symptom during psychomotor attacks. The results of our investigations show that it is no longer possible to regard it as a "curiosity", as did Janz (1969). It is an epileptic phenomenon like others and a symptom of automatism. It can occur in all phases of an attack. It is not remembered by the patient. We have been unable to establish any connection with age or sex. The form of expression is usually natural but inadequate and no affective motivation has been established. Laughter during an epileptic attack is an inborn emotional expression, structurally triggered by the involvement of the area around the hypothalamus-thalamic nucleus with the process causing the epilepsy. It is not actively experienced and is therefore not conscious and not an expression of the pleasant side of the affective complex moderated by the limbic system. The EEG's showed the usual variations occurring in psychomotor epilepsy. The temporal lobes are particularly involved. There is no "EEG Laughter Pattern". The group of patients considered here consist of severe, therapy-resistent cases of partial seizure epilepsy with pronounced cerebral lesions. In order to determine whether laughter is so common in less severe cases, a comparison group must be investigated. Laughter as a symptom of an epileptic attack is unknown to doctors and nursing staff and thus is either not recorded at all or, only very seldom. "Gelastic epilepsy" so-called does not exist as a nosology entity. This term should thus only be used--if at all--in cases where the laughter, together with a change in the level of consciousness, has over a period of years constantly been the only symptom of an attack, expecially when these attacks first became manifest in earliest childhood and are due to connatal changes in the hypothalamus-thalamic region.

Adolescent↗
PubMed1977

Fits of laughter (gelastic epilepsy) with a tumour of the floor of the third ventricle. A video tape analysis.

A patient with fits of laughter due to a tumorous alteration (hyperplasia) of the floor of the third ventricle is described with electroencephalographic findings indicative of focal epilepsy (complex partial seizures = psychomotor fits). The laughter is interpreted as an inborn emotional expression with structural substrate in the hypothalamus and neighboring brain. With structures remaining intact functional disorders in this area can cause epileptic phenomena with participation of the limbic system.

Adolescent↗
PubMed1976

Evaluation of extracorporeal alkylation of red cells as a potential treatment for sickle cell anemia.

Nitrogen mustard and nor-nitrogen mustard inhibit sickling, but the concentrations required would be associated with unacceptable toxicity if these agents were administered to patients. Red cells could be treated extracorporeally and infused back into donors, if the alkylating agent could be removed or inactivated, if the treatment per se did not significantly shorten red cell survival, and if viable alkylated lymphocytes could be eliminated from the treated blood. To estimate whether these conditions could be met in a clinical trial, red cells from four dogs were alkylated at 6-wk intervals. No toxic reactions were observed, although not all nor-nitrogen mustard was removed by the washing procedure. Red cell survival was shortened to about half that of control cells, using concentrations of alkylating agent which reduce sickling by 50%. Lymphocytes from treated blood could still exclude trypan blue, but could not be shown to circulate after reinfusion into donor dogs. If alkylating agents are used to treat patients' cells, inhibition of sickling may outweigh the shortening of red cell life span induced by the treatment; blood should probably be irradiated before infusion to avoid administration of alkylated and potentially mutated, but viable, lymphocytes.

Alkylating Agents↗
PubMed1976

[Television-EEG-department in research and clinical use (author's transl)].

The article reports about findings which have been acquired during a time of three and a half years of work in a television-EEG-department. Both, the individual construction elements as well as the entire conception are critically valuated according to their reliability and in view of their practical usefulness. After overcoming numerous technical difficulties the television-EEG-department has become a necessary instrument for research as well as for clinical work of a special hospital for epileptic seizures.

Electroencephalography↗