Search PubMed⌕ Search

Biomedical subjects

J Odink

Publications and source records attributed to J Odink.

At least 55 records · Page 3Linked to original sources
PubMed1988

Excretion of iodide in 24-h urine as determined by ion-pair reversed-phase liquid chromatography with electrochemical detection.

A simple method is presented for the routine analysis of iodide in urine. After a one-step sample clean-up, iodide was separated by ion-pair reversed-phase liquid chromatography and detected electrochemically with a silver electrode. The coefficient of variation of a single analysis of iodide in a pooled urine sample (530 nmol/l) was 7.6%. The detection limit, derived from a signal-to-noise ratio of 3, was 3 pmol, corresponding to 0.06 mumol/l. The recovery of iodide added to urine was 96 +/- 7%. The accuracy of the method was assessed by analysing ten different samples with neutron activation analysis. The data obtained with the two methods showed a high correlation (r = 0.991) and did not differ significantly. Excretion of iodide in samples of 24-h urine from a free-living population was shown to have a log-normal distribution and to be higher in men than in women. The iodide/creatinine ratio was independent of sex and increased with age.

Adolescent↗
PubMed1988

Simultaneous determination of the major acidic metabolites of catecholamines and serotonin in urine by liquid chromatography with electrochemical detection after a one-step sample clean-up on Sephadex G-10; influence of vanilla and banana ingestion.

A simple method is described for the simultaneous determination of vanilmandelic acid (VMA), 3,4-dihydroxyphenylacetic acid (DOPAC), 5-hydroxyindole-3-acetic acid (5-HIAA) and homovanillic acid (HVA) in urine. The compounds are isolated by a one-step sample clean-up on Sephadex G-10, separated by ion-pair reversed-phase liquid chromatography and detected electrochemically. A single analysis is completed within 65 min. Sample clean-up did not cause losses of the compounds of interest. The detection limits in urine were 0.4, 0.8, 1.0 and 1.6 mumol/l for VMA, DOPAC, 5-HIAA and HVA, respectively. 3,4-Dihydroxymandelic acid and vanillic acid (VA) were also detectable, but, under the chromatographic conditions used, they were not resolved from interfering components. VA and 5-HIAA could be analysed separately in the Sephadex G-10 eluate if more restrictive sampling conditions were used. Ingestion of bananas caused an increase of VMA, DOPAC, 5-HIAA and HVA in 24-h urine. After ingestion of vanilla an increased excretion of VA was observed, while the excretion of VMA, DOPAC and HVA was unaffected.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1988

Nutritional status in anorexia nervosa: clinical chemistry, vitamins, iron and zinc.

Routine clinical chemical variables and parameters of the vitamin, iron and zinc status were measured in 20 female patients with anorexia nervosa (AN) and in 10 lean and 10 normal weight, healthy, female control subjects. Patients with AN had higher activities of L-gamma-glutamyl transferase (gamma-GT) and glutamate pyruvate transaminase (SGPT) and a higher concentration of prealbumin in serum and lower leucocyte and lymphocyte counts in blood. For the other routine clinical chemical parameters no significant differences between the groups were observed. AN patients had higher serum vitamin B12 and retinol levels. No significant differences were found for the status parameters of thiamin, vitamin B6, vitamin C, folate, vitamin E and vitamin D. Contradictory results were obtained for the riboflavin status: AN patients had a lower level of flavin adenine dinucleotide (FAD) in blood and a lower stimulation ratio of the glutathione reductase activity in erythrocytes (alpha-EGR). Patients with AN had higher serum ferritin concentration and lower total iron binding capacity (TIBC). However, haemoglobin (Hb), haematocrit (Ht) and iron saturation were not significantly different. No significant difference was found in the concentration of zinc in plasma. In spite of the poor intake of nutrients and energy, the results obtained did not indicate an inadequate status of vitamins, iron and zinc in patients with AN.

Adolescent↗
PubMed1988

Food preferences and aversions and dietary pattern in anorexia nervosa patients.

Food intake, meal frequency and occurrence of vomiting and purging were assessed in 20 female patients with anorexia nervosa (AN) by two dietitians by means of a dietary history over the past month. Ten lean healthy women and 10 of normal weight served as two groups of controls. Two self-administered questionnaires, consisting of 51 questions each were developed and applied: one to get an insight into food preference and food aversion, another to evaluate the dietary pattern. A significant difference in energy intake was found between the patient group and both control groups, but not between the two control groups. Self-induced vomiting and weekly laxative use was only mentioned by the patients with AN. Between the patients and the controls significant differences were found in preference and aversion for several food products such as sugar, potatoes, meat, dates and bananas as well as in eating habits. Stepwise discriminant analysis of the data of the two questionnaires resulted in eight food items and three dietary pattern statements which specify group differences. It is concluded that the questionnaires used reveal important differences between anorexia patients and control subjects in attitudes towards foodstuffs, and can be a useful tool for early diagnosis when validated in larger samples of patients and controls.

Adolescent↗
PubMed1987

Type A behaviour, borderline hyperventilation and psychological, psychosomatic and neuroendocrine responses to mental task load.

Psychological, psychosomatic and neuroendocrine (in blood) responses to mental task load were investigated in relation to Type A behaviour and borderline hyperventilation. For this purpose 32 apparently healthy, male volunteers were classified on the basis of their scores on the Jenkins Activity Survey (JAS) and on a questionnaire assessing hyperventilation related symptoms (HRS). The subjects performed a memory search task in which a monetary bonus could be won or lost. At rest higher HRS scores were related to increased acute psychosomatic symptom scores and higher JAS scores to higher prolactin levels. Task performance caused an increase of state anxiety, acute psychosomatic symptoms, adrenaline and cortisol, whereas prolactin decreased. Higher JAS scores were related to greater cortisol responses and higher HRS scores to smaller adrenaline responses.

Adult↗
PubMed1986

Determination of free and total catecholamines and salsolinol in urine by ion-pair reversed-phase liquid chromatography with electrochemical detection after a one-step sample clean-up.

A simple method is presented for the routine determination of free and total catecholamines and salsolinol in urine. For the analysis of total catecholamines and salsolinol, the urine samples are first hydrolysed. The compounds are isolated by a one-step sample clean-up by cation-exchange chromatography and separated by ion-pair reversed-phase liquid chromatography and detected electrochemically. The method is suited for routine analysis. Pretreatment of ten samples for the high-performance liquid chromatographic analysis of free and total catecholamines and salsolinol is carried out in 4 h. A single analysis is completed in 30 min. The absolute losses of the compounds were less than 10%, except for epinephrine (20%). The detection limits were 0.9, 2.4, 4.8 and 6 nmol/l for norepinephrine, epinephrine, dopamine and salsolinol, respectively, in native urine. The values were twice as high for hydrolysed urine. The sample clean-up appears to be rather specific: apart from catecholamines and salsolinol, only those structurally related amines that contain a vicinal hydroxyl group are isolated.

Catecholamines↗
PubMed1986

Influence of tryptophan loading on urinary excretion of anthranilic acid and 3-hydroxyanthranilic acid by men and women as determined by alkali flame ionization gas chromatography.

A gas chromatographic method with alkali flame ionization detection is described for the determination of urinary total (free and conjugated) anthranilic acid (AA) and 3-hydroxyanthranilic acid (HAA) as their pentafluorobenzyl esters. Prior to analysis, urine was hydrolysed using hydrochloric acid in a boiling water bath. The highest AA and HAA yields were obtained with 4 M hydrochloric acid and a hydrolysis time of 4 h. The coefficients of variation of the between-run analyses of AA and HAA at the endogenous level were 7.2 and 5.8%, respectively. The average recovery for both substances was 84%. The method described has been used to study the excretion of AA and HAA in the urine of healthy males and females before and after an oral load of tryptophan. Furthermore, the influence of oral contraceptives has been investigated. Results indicate that for both sexes the excretion of AA in the urine was higher than that of HAA, except after tryptophan loading. The excretion of AA by women was higher than by men. For HAA, the results of both sexes were comparable. Furthermore, for neither of the sexes was a diurnal variation of AA or HAA observed. After tryptophan loading, the formation of HAA was increased by more than that of AA. Results obtained for women on oral contraceptives indicate a hormonal-induced inhibition of AA formation.

3-Hydroxyanthranilic Acid↗
PubMed1986

Effect of work load on free and sulfate-conjugated plasma catecholamines, prolactin, and cortisol.

The effects of maximal performance capacity and different work load intensities on the response of free and sulfate-conjugated plasma catecholamines, prolactin (PRL), and cortisol were studied in six healthy male volunteers. In a first experiment, the volunteers had to perform a step-wise incremental bicycle ergometer test to determine the onset of blood lactate accumulation (OBLA) and aerobic capacity (VO2 max). The levels of free noradrenaline (NE), adrenaline (Epi), and dopamine (DA) increased considerably, whereas no significant changes for sulfate-conjugated catecholamines, PRL, and cortisol were observed. In a second series of experiments with the same volunteers, the effects of 30 min exercise were studied at a constant work load intensity on 3 different days. Three intensities were used for each of the volunteers: 45%, 60%, and 75% of their aerobic capacity (i.e., below, close to, and above their OBLA). The values obtained for all parameters showed an intensity-dependent rise. The most important changes occurred at work load intensities above the OBLA. At the highest intensity, all parameters except sulfate-conjugated Ne and cortisol showed a significant increase. Although the physiologic parameters reached a steady state during exercise, there were no indications that this was the case with the values of the neuroendocrine parameters. Ten minutes after the exercise, the levels of the free catecholamines had declined considerably, whereas the values of the other parameters were unchanged or showed a further increase.

Adult↗
PubMed1985

Dietary intake, nutritional status and well-being of cancer patients: a prospective study.

Changes in dietary intake, nutritional status, body composition and well-being were studied in 108 cancer patients over a period of 20 weeks. The patients, constituting a group of elderly women with uterine cancer, a group of elderly men with urological cancer and a group of male and female patients of various ages with malignant lymphoma, were prospectively followed during and after aggressive treatment given with curative intent. Detailed information on the dietary intake was measured by a dietary history and cross-check method covering the 2 months prior to the onset of therapy and a 48-hr dietary record which was applied seven times during the observation period. The nutritional status was monitored by anthropometric measurements and laboratory assays in blood and urine. The patient's well-being was assessed by the use of standard performance scales by the observers and the application of patient's questionnaires concerning complaints, ability to self-care, mobility and daily activities. The main results are described here, indicating that: (1) most patients studied had a more than adequate diet during the 2 months preceding cancer therapy when compared to the Dutch Recommended Dietary Allowances; (2) the impact on dietary intake and nutritional status was relatively minor and generally transient; and (3) the treatment course was accompanied by distinct changes of well-being associated with, but not necessarily resulting from or leading to, changes of dietary intake.

Aged↗
PubMed1985

The influence of radiotherapy and chemotherapy on the vitamin status of cancer patients.

The influence of external abdominal irradiation and cytostatic therapy on the vitamin status was studied in patients with cancer of the uterus, bladder or prostate and in patients with malignant lymphoma. It was found that the vitamin status of these patients at the beginning of therapy in general was adequate, though vitamin A and vitamin D levels were reduced. During radiotherapy decreases of vitamin E, vitamin C, vitamin B12 and folic acid levels were observed. Chemotherapy caused a decrease of the folic acid levels after a few months. No clinical symptoms of vitamin deficiency were observed.

Ascorbic Acid↗
PubMed1984

Derivatization and mass spectrometric behaviour of catecholamines and their 3-O-methylated metabolites.

A method has been developed for the derivatization of both catecholamines (dopamine, noradrenaline and adrenaline) and their 3-O-methylated metabolites (3-methoxytyramine, normetanephrine and metanephrine) in a single run. The compounds were first incubated with methanolic hydrochloric acid to methylate those compounds that contain a benzylic hydroxyl group and were subsequently converted into their pentafluoropropionyl derivatives. The derivatives thus prepared, showed good gas chromatographic and electron-impact mass spectrometric properties and can be analysed in a single gas chromatographic run. The effect of the derivatization on exchange reactions in the aromatic ring was investigated because standard compounds with deuterium label in that part of the molecule are often used in isotope dilution measurements. The exchange of deuterium for hydrogen in the aromatic ring under derivatization conditions was found to be limited.

Catecholamines↗
PubMed1983

High-performance liquid chromatographic determination of urinary free catecholamines with electrochemical detection after prepurification on immobilized boric acid.

A reliable high-performance liquid chromatographic method is presented for the determination of the urinary free catecholamines noradrenaline, adrenaline and dopamine. Urine is purified on a column of immobilized boric acid. Catecholamines are separated by ion-pair reversed phase high-performance liquid chromatography and detected electrochemically. The method is suited for routine analysis. It allows the determination of urinary free catecholamines in concentrations as low as 1 microgram/1 for noradrenaline and adrenaline and 5 micrograms/1 for dopamine. A single analysis can be completed within 1 h. Routine analyses can be carried out in a series of 40 samples within 2 days. The within-assay and between-assay coefficients of variation of the analyses in urine were both 2.9% for noradrenaline, both 5.0% for adrenaline, and 1.9 and 2.1% for dopamine. The chromatographic properties of the immobilized boric acid were investigated. In particular, the elution pattern of a series of catecholamine metabolites and analogues was determined. Under the conditions used, only basic compounds containing both a vicinal hydroxyl configuration and a primary or secondary amino group adsorb and elute together with the free catecholamines.

Boric Acids↗
PubMed1980

The effect of galactose oxidase treatment on the hepatic binding and biological activity of desialylated human chorionic gonadotrophin.

125I labelled desialylated hCG (asialo-hCG) was treated with galactose oxidase, in order to find out whether oxidation of the terminal galactosyl residues would diminish the hepatic uptake of asialo-hCG. Specific binding to the hepatic asialo-glycoprotein receptor was monitored in vitro by a rat liver radioligand receptor assay (RRA). Hormonal activities were compared by ovarian RRA and by in vitro bioassay. Uptake studies were done in superovulated immature rats. Galactose oxidase treatment had hardly any influence on the in vitro ovarian binding and biological activity of [125I]asialo-hCG. Binding in the liver RRA was virtually abolished. In vivo hepatic uptake, however, was considerably above the level of [125I]hCG, as was the uptake in the kidneys. The hepatic uptake was inhibited by the administration of a high dose of asialo-fetuin. It is concluded that oxidation of the terminal galactosyl residues reduces the binding of asialo-hCG to the hepatic asialo-glycoprotein receptor, without affecting its hormonal properties. The ovarian uptake in vivo, however, is still limited by the high hepatic and renal clearance.

Animals↗
PubMed1980

Discrepancy between the effects of desialylation of human chorionic gonadotrophin on in vitro ovarian biological activity and on receptor binding.

An in vitro bioassay based on progesterone production by enzymatically-dispersed immature rat ovary cells, was used to investigate the effect of sialidase treatment on the biological activity of human chorionic gonadotrophin (hCG). The potency in this bioassay system and in an ovarian receptor assay were compared, to substantiate possible discrepancies between the effect of this treatment on biological activity and on receptor binding. Ovarian cells responded dose-dependently to the addition of hCG as well as sialidase treated hCG (asialo-hCG). Dose-response curves of hCG and asialo-hCG were parallel and the maximal stimulation levels reached were the same. Sub-maximal doses of hCG and asialo-hCG were additive. The potency of asialo-hCG was 65% of the original preparation. Addition of low concentrations of phosphodiesterase inhibitor resulted in a greatly enhanced sensitivity of the bioassay, but had no effect on the potencies of asialo-hCG and hCG. In contrast to intact gonadotrophins, the receptor assay potency of asialo-hCG was more than three times the bioassay potency. In agreement with this, it was found that when equal amounts of 125I-labelled hCG and asialo-hCG were specifically bound to the ovarian cells, the latter stimulated progesterone production less effectively. It is concluded that there is a discrepancy between the effect of desialylation on the biological activity and on the receptor-binding ability of hCG.

Animals↗
PubMed1979

A pitfall in the ovarian ascorbic acid depletion assay (OAAD): effect of unilateral ovariectomy, hCG and asialo-hCG.

The estimation of the effect of desialylation on the biological activity of human chorionic gonadotrophin (hCG), as determined in the ovarian ascorbic acid depletion assay (OAAD), according to the modification in which the animals are used twice, appeared to be dependent on the assay conditions. Animals which received hCG in the first assay (OAAD-1) gave higher potency estimates for hCG and asialo-hCG in OAAD-1. The results of the experiments indicate that the ovarian sensitivity for hCG and asialo-hCG is increased after administration of hCG and unilateral ovariectomy and decreased after administration of asialo-hCG.

Animals↗
PubMed1979

Ovarian binding and intrinsic biological activity of desialylated human chorionic gonadothrophin (ASIALO-hCG).

The present study was undertaken to investigate the effect of desialylation on the intrinsic in vivo biological activity of hCG. To block the hepatic uptake of asialo-hCG we investigated asialo-orosomucoid. The biological activity of hCG and asialo-hCG was estimated with the ovarian ascorbic acid depletion assay (OAAD). The uptake studies were performed with [125I]hCG and [125I]asialo-hCG. Desialylation of hCG increased its hepatic uptake, almost completely abolished its ovarian uptake, and reduced its in vivo biological activity to less than 1%. Administration of asialo-orosomucoid caused a reduction of the hepatic uptake of asialo-hCG to the level observed for hCG. The ovarian uptake increased, but was lower than observed for hCG, due to a considerably higher renal accumulation of asialo-hCG. The in vivo biological activity of asialo-hCG was approximately 1/5 of the activity of hCG when both were tested in the presence of asialo-orosomucoid. To exclude the interference of renal accumulation, binding and biological activity were also investigated after bilateral nephrectomy. The uptake of radioactivity in the ovaries following injection of [512I]asialo-hCG and asialo-orosomucoid was then almost the same as observed after injection of [125I]hCG alone. When both preparations were now tested in the presence of asialo-orosomucoid, the in vivo biological activity of asialo-hCG appeared to be approximately 1/3 of the value obtained for hCG. It is concluded that the intrinsic in vivo biological activity of hCG is lowered by desialylation.

Animals↗