Free amino acid levels were measured in cerebrospinal fluid (CSF) from demented patients (D, n = 30) suffering from presenile and senile dementia of Alzheimer type (PDAT, n = 7; SDAT, n = 9), multi-infarct dementia (MID, n = 14) and a reference sample group consisting of young neurotic patients (R, n = 16). Comparing the amino acid levels in the dementia subgroups, significantly higher alanine, methionine, phenylalanine and tyrosine levels were found both in MID and SDAT vs. PDAT. No difference was seen between SDAT and MID. Compared to the reference sample group, higher glycine levels were found in each dementia subgroup; higher alanine, methionine and ornithine levels in MID, and SDAT; and higher phenylalanine levels in MID. In PDAT the level of tyrosine was lower. Coefficients of correlation were calculated between amino acid levels and age, and the findings in the reference sample groups were divergent from those observed in dementia. The differences observed are discussed in terms of amino acid, carbohydrate and neurotransmitter metabolism.

Age Factors↗

PubMedDate not supplied

Ascorbic acid in cerebrospinal fluid - a possible protection against free radicals in the brain.

The function of ascorbic acid in living organisms is complex. Previous studies emphasize its protective role against harmful effect of free radicals, and its presence is necessary for the function of numerous enzymes. Ascorbic acid is a powerful reducing agent due to its dienol molecular structure, which is not present in the oxidized form, dehydroascorbic acid. The ratio of ascorbic acid and dehydroascorbic acid might be a marker of oxidative-reductive processes. We measured and compared the level of ascorbic acid and dehydroascorbic acid in the plasma of healthy persons and those of senile dementia patients, who represent pathological aging of the brain. In senile dementia patients, ascorbic acid and dehydroascorbic acid levels were also measured in the cerebrospinal fluid. Concentrations were determined by high performance liquid chromatography with electrochemical detection. In the plasma of senile dementia patients, very low ascorbic acid levels were found (ca. 30% of the healthy control). In lumbar cerebrospinal fluid, the concentration of ascorbic acid is 2.7 times higher compared to that of the plasma level. After intravenous infusion of ascorbic acid, a slow but marked increase of the concentration in the cerebrospinal fluid was measured. Our results support an active transport process for ascorbic acid through the blood-CSF barrier. Ascorbic acid level might be an important factor representing the protection of the central nervous system against free radicals.

Journal Article↗

PubMedDate not supplied

Archives of gerontology and geriatrics. Preface.

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Journal Article↗

PubMedDate not supplied

[Relationship between clozapine plasma levels and withdrawal symptoms].

Discontinuation of clozapine and an attempt to change his medication to sertindol has led to serious psychotic and somatic symptoms in an schizophrenic patient treated with clozapine for five years, however after readministration of clozapine these symptoms rapidly disappeared. To further analyse the case we have developed an HPLC method for the measurement of plasma levels of clozapine and its main metabolite N-desmethyl clozapine in order to monitor the plasma levels of clozapine and to correlate with the clinical symptoms. The present results confirmed that after discontinuation of clozapine no measurable amount of drug or its main metabolite were present in the plasma of the patient. The correlation between the plasma levels of clozapine and the changes in the clinical state of the patient confirmed that the patient's severe psychotic and somatic symptoms were the result of discontinuation of clozapine treatment. The clozapine plasma concentration of the patient reported here was low (100 ng/ml) compared to the generally accepted plasma levels for antipsychotic action of clozapine (350 ng/ml), however the somatic and psychotic clozapine withdrawal symptoms rapidly and completely disappeared.

Adult↗