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Biomedical subjects

J C Kok

Publications and source records attributed to J C Kok.

8 recordsLinked to original sources

Can determination of lactic acid and pyruvic acid in cerebrospinal fluid help in diagnosing central nervous system involvement in systemic lupus erythematosus?

The central nervous system (CNS) is frequently affected by systemic lupus erythematosus (SLE). Other causes, especially infection, may also originate CNS disease in SLE patients. Our findings indicate that measurement of lactic acid and pyruvic acid in cerebrospinal fluid (CSF) may be of help in separating inactive CNS-SLE from active CNS-SLE. Also it may be of help in differentiating sterile meningitis caused by SLE from bacterial meningitis. Because of the special risk on tuberculous and fungal infections in SLE patients, also some findings concerning these specific forms of meningitis are given.

Central Nervous System Diseases↗

In vitro studies of 5, 10-methylenetetrahydrofolate reductase: inhibition by folate derivatives, folate antagonists, and monoamine derivatives.

Folate monoglutamates and folate antagonists have an inhibitory action on the activity of 5,10-methylenetetrahydrofolate reductase in rat brain. The type of inhibition was studied for dihydrofolic acid using the Lineweaver--Burk transformation. Some of the monoamine alkaloids, the in vitro products of 5,10-methylenetetrahydrofolate reductase, have either a stimulatory or inhibitory effect on the enzyme activity.

Animals↗

A patient with pyruvate carboxylase deficiency in the liver: treatment with aspartic acid and thiamine.

A seven-year-old girl with slowly progressive motor neurological impairment and high levels of lactate and pyruvate in blood and cerebrospinal fluid was found to have severe hepatic pyruvate carboxylase deficiency. However, in contrast to other patients with this deficiency, no mental retardation was apparent. Treatment with aspartic acid and thiamine over a period of seven years resulted in biochemical improvement and a stable neurological condition. The level of cognitive functioning remained the same. When treatment with aspartic acid was temporarily discontinued, lactate and pyruvate concentrations increased so markedly that the drug was resumed. This indicates that aspartic acid was the effective drug, and that the effect of thiamine was secondary.

Aspartic Acid↗

Bone marrow imaging with 59Fe.

Commerically available collimators are not suitable for the visual demonstration of the kinetics of 59Fe, because of its physical properties. A locally designed collimator, that provides integral visual information of the whole body distribution of erythropoietic marrow, is discussed. Wholebody scans of 4 individuals are also included to demonstrate the capabilities of the collimator.

Adult↗

Effects of change in dietary folic acid content on pentylenetetrazol seizure threshold in rat.

Pentylenetetrazol (PT) eeg thresholds were measured in rats on a folic acid (FA) deficient diet, normal diet, and a diet supplemented with large amounts of folic acid. The intraperitoneal dose per kilogram body weight of PT is significantly higher in the FA deficient group and significantly lower in the FA supplemented group than in rats on a normal diet. This indicates an effect of FA metabolism on PT epilepsy. The Lactobacillus casei minus Streptococcus faecalis activity of the brain is decreased in the FA deficient and increased in the FA supplemented group. The relation between brain folate metabolism and epilepsy is discussed.

Animals↗