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T Hafner

Publications and source records attributed to T Hafner.

6 recordsLinked to original sources
PubMed1992

Blockade of GABAB receptors accelerates amygdala kindling development.

The aim of this study was to investigate the putative role of GABAB receptors in the development of amygdala kindling in rats. The effects of the GABAB blocker CGP 35348 and the GABAB agonist baclofen on the progressive development of behavioural seizure symptoms (stages 1-5 classified by Racine) and duration of after-discharges (AD) were studied. CGP 35348 at a dose of 300 mg/kg i.p., which blocks central GABAB receptors, moderately but consistently accelerated the development of behavioural seizure symptoms. CGP 35348 had no marked effect on the duration of ADs corresponding to the different seizure stages. L-baclofen (6 mg/kg i.p.) had a dual effect on kindling development. It retarded the development of the behavioural symptoms, but increased the duration of AD. In conclusion, the results suggest that synaptically-released GABA activated GABAB receptors and thereby exerted a depressant effect on kindling development.

Amygdala↗
PubMed1988

Gamma-vinyl GABA: comparison of neurochemical and anticonvulsant effects in mice.

Biochemical and pharmacological effects of gamma-vinyl GABA (Vigabatrin, GVG), and irreversible enzyme-activated inhibitor of 4-aminobutyrate: 2-oxoglutarate aminotransferase (EC 2.6.1.19; GABA-T), were measured in mice. This anticonvulsant produced a time- and dose-dependent elevation of the GABA, phenylalanine and lysine contents of cortical tissue and simultaneously decreased glutamate, aspartate and alanine levels. In addition, GVG caused a biphasic change in glutamine concentrations (a decline 1-4 hours after administration, followed 20 hours later by an increase). Moreover, we found a new, as yet unidentified amino acid in the brain eluting with the same retention time as alpha-aminoadipic acid from an HPLC cation-exchange column. The level of this novel chemical entity was greatly increased by GVG 20 hours after injection of the drug. At all tested intervals between 1 and 60 hours after injection, GVG was ineffective against maximal electroshock. The GABA-T inhibitor dose-dependently protected mice against isoniazid-induced seizures, simultaneously causing an increase in brain GABA concentrations. However, this apparent correlation applied only until 4 hours after treatment. To better define the anticonvulsant profile of GVG, groups of mice were treated, 1, 2, 4, and 24 hours prior to challenge with convulsant doses of strychnine, pentetrazole (PTZ), and picrotoxin, and brain amino acid levels, including brain concentrations of GVG, were measured. In all instances, the time dependency of the anticonvulsant effects of GVG and of increases in brain GABA levels differed. Amino acid concentrations in animals treated only with GVG were similar to those in animals given GVG and a chemical convulsant. GVG showed no selectivity for seizures produced by impairment of GABA-ergic neurotransmission. Although GVG is an effective GABA-T inhibitor, it apparently affects several other pyridoxal-phosphate-dependent cerebral enzymes and/or interacts with other neurotransmitter systems as well.

4-Aminobutyrate Transaminase↗
PubMed1978

[Localization of Hodgkin's disease and non-Hodgkin lymphoma by means of 67 gallium subtraction scintigraphy].

67Ga-subtraction scan was found to be useful and a promising new method for the pre-treatment evaluation of the patient with Hodgkin's disease or non-Hodgkin's lymphoma. The scan appeared to be most accurate in the neck, chest, and axillary regions. It appears to offer a means of increasing the accuracy of evaluating the abdomen, the paraaortic and pelvic regions. It may be a useful method for follow-up to detect recurrences. It was an easily performed, safe, non-invasive test, well tolerated and accepted by patients.

Adult↗
PubMed1978

67Ga-subtraction scanning in Hodgkin's disease and lymphomas.

Recently a new method was described, the 67Ga subtraction scanning method. 67Ga accumulates in neoplastic and inflammatory tissue. The subtraction method was applied for evaluating 38 patients with Hodgkin's disease and non-Hodgkin's lymphoma. The preliminary experiences are described. It was found that the diagnostic accuracy is comparable to that of 67Ga scanning. The subtraction method offers potential improvement of the accuracy for equivocal scans, but further technological refinement is needed before the method can be widely applicable.

Diagnostic Errors↗
PubMed1977

Localisation of Hodgkin's disease and lymphomas by 67-gallium substraction scanning.

67Ga-subtraction scan was found to be useful and a promising new method for the pre-treatment evaluation of the patient with Hodgkin's disease or non-Hodgkin's lymphoma. The scan appeared to be most accurate in the neck, chest, and axillary regions. It appears to offer a means of increasing the accuracy of evaluating the abdomen, the para-aortic and pelvic regions. It may be a useful method for the follow-up to detect recurrences. It was an easily performed, safe, non-invasive test, well tolerated and accepted by patients.

Abdominal Neoplasms↗