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Biomedical subjects

D A Dick

Publications and source records attributed to D A Dick.

At least 19 recordsLinked to original sources
PubMed1982

Plasma vanadium concentration in manic-depressive illness.

133 samples of plasma taken from 9 normal control and 8 manic-depressive subjects were analysed for vanadium by atomic absorption spectrometry. Mean plasma vanadium concentrations were 0 . 15 microM in normal control, 0 . 34 microM in manic and 0 . 28 microM in depressed subjects, and 0 . 23 microM in manic-depressive subjects after recovery. The differences between normal subjects and manic and recovered subjects were statistically significant. Significant negative correlations were found between plasma vanadium concentration and the ratio of Na-K-Mg ATPase to Mg-ATPase in 2 manic-depressive subjects, but not in normal subjects. The results suggest that vanadium may be a cause of the variations in Na-K-Mg ATPase and sodium pump activity which are associated with manic-depressive illness.

Bipolar Disorder↗
PubMed1982

The distribution of sodium and potassium in toad (Bufo bufo) oocytes estimated by a stereological method.

As the toad oocyte grows, the intracellular Na concentration rises and the K concentration falls. By stereological analysis using a point counting method in a projection apparatus, it is shown that as the oocyte grows the volume density of the nucleus, endoplasmic reticulum and mitochondria falls, while that of the yolk platelets and cytoplasmic vesicles rises. A multiple regression analysis applied to the sodium and potassium concentrations and to the volume densities of the subcellular components indicates that sodium is most concentrated in cytoplasmic vesicles while potassium is most concentrated in a component composed of the cell cytoplasmic ground substance, the mitochondria and the cell nucleus.

Animals↗
PubMed1980

Prediction of clinical course of bipolar manic depressive illness treated with lithium.

A group of bipolar manic depressive patients attending a routine lithium clinic were investigated. The results suggest that, when on treatment with lithium, manic depressive patients with a good prognosis tend to have a higher erythrocyte Na-K ATPase and higher plasma and erythrocyte lithium concentrations than those with a poor prognosis. There was no evidence to suggest that the erythrocyte: plasma lithium ratio was useful in predicting clinical response to lithium therapy. There was also a positive correlation between plasma lithium concentration and Na-K ATPase activity, confirming that in manic depressive subjects lithium produces a rise in erythrocyte Na-K ATPase activity.

Bipolar Disorder↗
PubMed1980

Erythrocyte membrane cation carrier in manic-depressive psychosis.

Erythrocyte Na-K ATPase and sodium pump site numbers were estimated in groups of depressed, manic and recovered patients. The activity of Na-K ATPase per pump site was lower in the depressed group than in the recovered group. In the manic group Na-K ATPase was lower than that of the recovered group, whereas there was no difference in the pump site numbers. In the more severe manics the activity of Na-K ATPase per pump site was significantly lower than that of the recovered patients. Therefore, the change occurring in the erythrocyte membrane cation carrier in manic-depressive psychosis is probably in the activity of individual Na-K ATPase molecules and not in the number of Na-K ATPase molecules per cell.

Binding Sites↗
PubMed1979

Lithium side effects in a routine lithium clinic.

Approximately two thirds of a group of bipolar patients attending the routine lithium clinic suffered sid effects. These patients tended to have a lower plasma and erythrocyte lithium concentration and a lower erythrocyte/plasma lithium ratio than those who had no side effects. Explanations of this unexpected finding are discussed.

Bipolar Disorder↗
PubMed1978

The distribution of sodium, potassium and chloride in the nucleus and cytoplasm of Bufo bufo oocytes measured by electron microprobe analysis.

1. Measurements of cytoplasmic and nuclear Na, K and Cl have been made by electron microprobe analysis on freeze-dried sections of oocytes of Bufo bufo, using standards of bovine plasma albumin and gamma-globulin. Concentrations were obtained per kilogram of dry mass, were converted to concentrations per litre of water content using known figures for water and solid concentration of nucleus and cytoplasm, and were then compared with measurements on cells from the same animal obtained by flame photometry. 2. In fresh oocytes concentrations were (mean +/- S.E. of mean in m-mole/l. H2O) in cytoplasm Na 10.9 +/- 1.95, K 70.2 +/- 3.22, Cl 98.8 +/- 11.0, and in nucleus Na 10.4 +/- 1.79, K 266.4 +/- 22.8, Cl 91.3 +/- 9.0. 3. After treatment with Na-free Ringer (Li substituted for Na) for 5 hr, concentrations were in cytoplasm Na 11.1 +/- 2.44, K 64.4 +/- 5.7, Cl 88.7 +/- 8.8, and in nucleus Na 2.4 +/- 0.73, K 141 +/- 13.9, Cl 75.0 +/- 6.7. Na inexchangeable with Li therefore lay in the cytoplasm but not in the nucleus as previously shown by autoradiography. 4. For K electron microscopic analysis measurements agreed well with those obtained by flame photometry but the former measured only 35% of Na measured by flame photometry. This discrepancy may be due either to technical difficulties with the electron microprobe analysis or to localization of Na in the cytoplasm.

Animals↗
PubMed1977

Lithium and erythrocyte membrane cation carrier studies in normal and manic depressive subjects.

Changes in the erythrocyte membrane cation carrier following lithium ingestion in normal human subjects were studied; ouabain sensitive potassium influx fell significantly during the lithium treated phase. Lithium was fed to rats and no change in erythrocyte Na-K ATPase was shown. These findings contrast with studies of lithium in manic depressive psychosis. The fluctuations in the erythrocyte membrane cation carrier were studied in 5 normal subjects over 12 weeks and the correlations between the parameters calculated. The erythrocyte sodium concentration correlated positively with the ouabain sensitive potassium influx. This too contrasts with findings in manic depressive psychosis.

Adenosine Triphosphatases↗
PubMed1977

Changes in the erythrocyte sodium pump with age.

Various estimations of the erythrocyte sodium pump were determined in 18 female and 11 male adult subjects. In the female group, but not in the male group, the sodium concentration increased with age; the erythrocyte active transport decreased and passive transport increased with age and could account for the observed change in erythrocyte sodium concentration with age. The erythrocyte Na-K ATPase decreased with age in the females and this could account for the observed change in active transport.

Adenosine Triphosphatases↗
PubMed1976

Erythrocyte membrane cation carrier, relapse rate of manic-depressive illness and response to lithium.

Biochemical studies of manic-depressive psychosis usually correlates biochemical findings with current affective state and hence any significant findings could be secondary to mood change. The present study attempts to correlate measures of the erythrocyte membrane cation carrier with clinical events, remote in time from the biochemical assay. Eprythrocyte sodium concentration, ouabain-sensitive potassium influx and Na-K ATPase were estimated in 11 patients before and after the cross-over point in a 2-year double blind clinical trial ratio tended to suffer most episodes of affective illness in the 2 years. Patients who had a low initial Na-K ATPase or a high initial flux sodium ATPase ratio, or in whom this ratio fell most with lithium or whose Na-K ATPase rose most with lithium, clinically responded best to lithium.

Adenosine Triphosphatases↗
PubMed1976

Erythrocyte membrane cation carrier in mania.

Erythrocyte sodium and potassium concentrations, erythrocyte membrane ATPase (Na-K specific and non-specific) and the rate of potassium influx into erythrocytes (ouabain-sensitive and insensitive) were estimated in a group of female patients suffering from mania and repeated on about two thirds of them when they had recovered. With recovery there was a statistically significant increase in the erythrocyte ouabain-sensitive potassium influx. The other parameters showed no significant overall change with recovery but the initial severity correlated significantly and negatively with the change in erythrocyte Na-K ATPase with recovery. The changes that occurred in the erythorcyte sodium concentration and Na-K ATPase activity were not random since they correlated significantly with changes in the active potassium influx.

Adenosine Triphosphatases↗
PubMed1976

Nonuniform distribution of sodium in the rat hepatocyte.

The volume of the nucleus, endoplasmic reticulum (including Golgi complex), mitochondria, and cytoplasmic ground substance was measured in rat hepatocytes by stereological methods. The Na content was also measured by flame photometry. Variations in Na content correlated significantly with variations in volume of nucleus and endoplasmic reticulum. From the correlation parameters, Na concentrations were estimated as follows: nucleus, 108 mM; endoplasmic reticulum (ER) (including Golgie complex) 27 mM; cytoplasm (including and remaining organelles) 16 mM.

Animals↗
PubMed1976

A biochemical study of short-cycle manic-depressive psychosis in mental defectives.

Four mentally defective patients who were suffering from short-cycle manic-depressive psychosis were each studied under metabolic ward conditions for about six months. Weekly estimations of erythrocyte Na-K ATPase activity, ouabain sensitive potassium influx, sodium concentration, whole blood cell ATP concentration and blood haematocrit were made. The findings in each patient differed, but the erythrocyte Na-K ATPase activity, sodium and ATP concentration appeared to show cyclic changes related to, though out of phase with, the clinical state.

Adenosine Triphosphatases↗