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J G Goekoop

Publications and source records attributed to J G Goekoop.

30 records · Page 2Linked to original sources
PubMed1990

Osmotic behavior of erythrocytes from patients with a major affective disorder. A freeze-fracture electron microscopic study.

Previously we have demonstrated a state-dependent decrease in the number of membrane vesicles in erythrocytes from patients with a major depressive episode. We now report an increase in the number of membrane vesicles during a manic episode as well as a reduction during lithium treatment and we also present data suggesting that the number of erythrocyte membrane vesicles in the affective disorders is dependent on osmotic shrinkage due to the freezing for freeze-etch electron microscopy. Although caution is required since the interrater reliability of the measurement of osmotic strain was insufficient in the mid range where it was tested, we do not think this invalidates the differences in osmotic strain found in the low and high ranges during depressive and manic episodes respectively. These findings warrant the use of more precise techniques in studies of the osmotic behavior of erythrocytes from patients with a major affective disorder.

Adult↗
PubMed1990

Clinical use of the determination of serotonin in whole blood.

Whole blood serotonin (5-hydroxytryptamine, 5-HT) was assayed, and factors possibly influencing 5-HT content were investigated in healthy controls. No significant circadian rhythm or effect of dexamethasone or meals was observed. After use of fluvoxamine, a specific 5-HT reuptake inhibitor, the whole-blood 5-HT concentration of patients was strongly reduced. After treatment with tranylcypromine, an unspecific monoamine oxidase inhibitor (MAOI), the 5-HT content was increased. Determination of whole blood 5-HT in patients treated with fluvoxamine presents a measure of drug compliance. Furthermore, the method may have clinical potential for finding an adequate dose when a 5-HT reuptake inhibitor or an MAOI is used.

Adult↗
PubMed1986

Lymphocyte concanavalin A capping: a similarity between Down's syndrome and early onset primary degenerative dementia.

Lymphocyte capping with concanavalin A was studied in adult patients with Down's syndrome and aged patients with primary degenerative dementia. In both disorders a decreased capping was found as compared with age-matched and clinically relevant control groups. Colchicine had a strong enhancing effect on capping in Down's syndrome. In primary degenerative dementia the enhancing effect of colchicine was restricted to a subgroup of patients with onset of the dementing illness before the age of 80 years.

Adult↗
PubMed1984

Decreased erythrocyte membrane elevations in patients with a major depressive episode.

Washing of erythrocytes from healthy volunteers in an isotonic sodium chloride solution at pH 5.6 results in the occurrence of plasma membrane elevations as observed in freeze-etch electron microscopy. This is prevented by anion permeability inhibiting agents. In the absence of these agents a reduced number of elevations was found in 23 of 36 patients with a major depressive episode. This reduced capacity to form membrane elevations was positively correlated with a genetic vulnerability, defined as an admission to a psychiatric hospital in first-degree relatives.

Adolescent↗
PubMed1980

The appearance of erythrocyte membrane elevations. Effects of cooling rates.

Low cooling rates during the freezing procedure of normal human blood reveals red cell membrane elevations in freeze-etch electron microscopy. When high cooling rate is applied, these morphological changes are present, if the blood samples are quenched from 5 degrees C. The number of elevations is strongly reduced by low pH and glycerol. Elevations are not observed in ghosts. The formation of intramembrane particle aggregation is differently affected by many conditions.

Anticoagulants↗
PubMed1978

PH-dependent behavior of erythrocyte membrane elevations. II Occurrence in moderate acidemic and alkalemic conditions.

Changes of the number of red cell membrane elevations revealed by freeze-etch electron microscopy are pH-dependent in vitro and in vivo. In healthy volunteers a decrease of the number of red cell surfaces with elevations was observed under moderate acidemic and alkalemic conditions. These changes were different in patients with Huntington's chorea and affective psychotic disorders. Elevations of the red cell membrane with the same diameter can be demonstrated in ultrathin sections, if sodium azide is added during the fixation procedure.

Erythrocyte Membrane↗
PubMed1978

pH-dependent behaviour of erythrocyte membrane elevations.

Freeze-etch electron microscopy of human erythrocytes from heparinized normal blood reveals membrane elevations. These elevations disappear at low pH values and reappear under normal pH conditions in vitro, both in the absence and the presence of plasma. This pH-dependent behaviour is discussed as an intrinsic membrane event.

Anticoagulants↗