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Biomedical subjects

A Struyvenberg

Publications and source records attributed to A Struyvenberg.

At least 37 records · Page 2Linked to original sources
PubMed1991

Iron metabolism in patients with the anaemia of end-stage renal disease during treatment with recombinant human erythropoietin.

Iron metabolism was studied in 21 patients with the anaemia of end-stage renal disease during 40 weeks of treatment with recombinant human erythropoietin (rhEPO). Oral iron was prescribed to all patients. Initial serum iron concentrations and transferrin saturation levels were subnormal, decreased during the correction period of treatment, and increased thereafter. In 81% of patients in whom pretreatment transferrin saturation was below 0.25, transferrin saturation decreased below 0.16, despite sufficiently high serum ferritin levels. Serum ferritin concentrations decreased significantly. There was no correlation between serum ferritin levels and serum iron or transferrin saturation. Ferrokinetic studies, performed before and during treatment, showed an increase in plasma iron turnover, in erythron transferrin uptake, and in the flux of iron binding sites through the plasma. The rhEPO dose needed to keep the haematocrit at the target level during the maintenance period of treatment was significantly correlated with transferrin saturation, and iron binding capacity, but not with serum ferritin concentrations. This suggests that the functional availability of iron in plasma, rather than the size of body iron stores, is a major factor in the determination of the response to rhEPO treatment in end-stage renal disease.

Adolescent↗
PubMed1990

[Hypertension consensus in The Netherlands].

It is known that mild hypertension is a common disorder and there is increasing evidence that it is possible to decrease the incidence of cardiovascular damage by antihypertensive treatment. Stimulated by the controversy on the identification and treatment of patients with mild hypertension, a Dutch hypertension consensus meeting was held on March 16th 1990. Consensus was reached that the decision to treat should be taken on the basis of both the blood pressure level and the individual risk profile, including hypercholesterolaemia, history of smoking, diabetes, or a family history of cardiovascular disease. Subjects at risk should be identified by selective case finding (persons with known additional risk factors) and screening restricted to men aged 55 to 65 years. All patients should be started on non-pharmacological treatment by decreasing sodium intake, and where necessary reducing body weight and alcohol consumption, and stopping smoking. If antihypertensive drugs are to be given, diuretics, beta-blockers, ACE-inhibitors, and (or) calcium antagonists are the drugs of choice.

Age Factors↗
PubMed1990

Preliminary report: complement activation in wasp-sting anaphylaxis.

The generation of the anaphylatoxin C3a was measured after a wasp-sting challenge in eight patients with previous anaphylactic reactions to wasp stings. Whereas there was no change in C3a in one patient who showed no reaction and only a slight rise in three patients with mild reactions, C3a rose substantially in the four patients with severe anaphylactic reactions. This complement activation is the first in-vitro variable which correlates with the severity of wasp-sting anaphylactic reactions. A role for complement activation in the pathophysiology of wasp-sting anaphylaxis is therefore suggested.

Adult↗
PubMed1990

[An end to routine urea determinations].

When information regarding kidney function is sought, the laboratory is often requested to measure both creatinine and urea. In contrast to creatinine, however, blood urea is not an adequate measure of GFR. Therefore measurement of urea in general does not contribute to the problem solving process and merely increases expenditure. In one large hospital the routine requests for measurement of urea, amounting to approximately 2500 per month, were studied. It could be shown that these rarely contributed to the diagnosis. It is concluded that, in line with the efforts to decrease the costs of health care, urea should only be measured in selected cases.

Cost Control↗
PubMed1990

A phase 1 and pharmacokinetic study using the aromatic retinoic acid analogue dichloroetretinate (Ro 12-7554).

A phase I study was carried out with the new aromatic retinoic acid analogue DCE, all-trans-9-(2,6-dichloro-4-methoxy-m-tolyl)-3,7-dimethyl-2,4,6,8- nonatetraenacetylester. Data from preclinical studies show that DCE has a promising anti-tumor effect. Data from others investigators show that when DCE was given to patients in daily doses, the dose-limiting toxicity. This toxicity was comprising considerable muco-cutaneous toxicity, occurred at 40 mg/day. To avoid this dose-limiting toxicity, a weekly oral treatment schedule was tested for toxicity in this study. The starting dose was 40 mg/m2 body surface, and a modified Fibonacci scheme was used for the dose escalations. A total of 20 patients entered this study, and all were evaluable for toxicity. The highest dose was 300 mg/m2. In three patients, completely reversible WHO grade 1 liver toxicity was observed. In contrast to daily doses, a once-a-week schedule produced no mucocutaneous toxicity. Pharmacokinetic measurements showed that absorption was highly unpredictable and did not increase with dose increments. Given the results of the pharmacokinetic determinations, we concluded that escalating the DCE dose would not lead to a recommendable dose for further phase II studies, and the study was subsequently discontinued.

Adult↗
PubMed1990

Insulinomas in MEN-I patients: early detection and treatment of insulinomas in patients with the multiple endocrine neoplasia syndrome type-I.

In the multiple endocrine neoplasia syndrome type I (MEN-I syndrome), periodic screening of patients and their close relatives may improve prognosis and life expectancy. Although there is diffuse involvement of the pancreas with microadenomatosis, insulinomas in the MEN-I syndrome usually occur as single tumours. This is illustrated here by two patients with insulinomas and the MEN-I syndrome. Preoperative localization of the tumours was achieved accurately by digital subtraction angiography combined with dynamic computerized tomography after a bolus injection of contrast medium. At present, two and three years after elective surgery both patients are asymptomatic. The early detection and treatment of insulinomas is extremely important because of the high risk of cerebral damage associated with late diagnosis. Periodic investigation of MEN-I family members can promote the early diagnosis and treatment of insulinomas, especially in young patients, whose life expectancy and quality of life may be improved.

Adolescent↗
PubMed1989

Ten-year survival and late sequelae in testicular cancer patients treated with cisplatin, vinblastine, and bleomycin.

This 10-year follow-up study of 91 patients with disseminated testicular nonseminomatous cancer, treated with cisplatin, vinblastine, and bleomycin (PVB) induction chemotherapy and vinblastine plus bleomycin maintenance chemotherapy for a planned period of 2 years, shows a 63% cure rate. The predominant long-term sequelae are neurological and sexual dysfunction in 68% and 40% of patients, respectively. Two patients died of myocardial infarction. Sixteen percent of patients developed hypertension, 23% Raynaud's phenomenon, and 25% ototoxicity. Despite the long-term side effects, 90% of the patients who responded to a questionnaire are fully employed. This study shows that the maintenance chemotherapy has contributed to the incidence and/or degree of neurotoxicity, hypertension, and renal function disturbance.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Hypokalaemia in hypertensive patients treated with diuretics: no increase in cardiac arrhythmias.

Hypokalaemia is a risk factor for the development of cardiac arrhythmias, at least in patients with a cardiac disease, but it is not known whether this applies to subjects with normal hearts. In the present study, 8 young patients with essential hypertension were treated with chlorthalidone for 12 wk followed by a combination of chlorthalidone (50 mg/day) and triamterene (100 mg/day) for 6 wk. This protocol was chosen in order to create different phases in the intra- and extracellular potassium concentrations. At the end of each 6-wk period, blood analyses were performed together with whole body counting for 40K, 24-h electrocardiogram registration, and ergometry. Although plasma potassium concentration and total body potassium decreased significantly in the chlorthalidone period and increased significantly in the period when triamterene was administered together with chlorthalidone, no changes in ectopic activity were seen during either 24-h registration or ergometry. It is concluded that, although hypokalaemia may be dangerous in patients with diseased hearts, a similar risk could not be established in subjects with a normal heart and uncomplicated essential hypertension. Whether the conclusion applies to the average patient with essential hypertension is still a subject of study.

Adult↗
PubMed1988

[Digoxin].

Explore the source record for details and available documents.

Digoxin↗
PubMed1988

Decrease of plasma potassium due to inhalation of beta-2-agonists: absence of an additional effect of intravenous theophylline.

The effect on the plasma potassium concentration of inhalation of the beta-2-agonists fenoterol, salbutamol (albuterol), and terbutaline from metered-dose inhalers was studied in normal volunteers. All three drugs caused a significant, dose-dependent decrease, more pronounced for fenoterol and salbutamol than for terbutaline. Relative to the bronchodilating potency (one puff of fenoterol 0.2 mg is considered to be equivalent to two puffs of salbutamol 2 x 0.1 mg, or two puffs of terbutaline 2 x 0.25 mg), fenoterol had a more pronounced effect on plasma potassium than salbutamol or terbutaline. The systemic effect on plasma potassium seems to be related to the structure of the drugs: the more lipophilic the drug (fenoterol) the sooner the systemic symptoms appear and the more pronounced they are. The effects of theophylline alone, and combined with fenoterol, were also studied. The intravenous infusion of theophylline (after placebo inhalation; maximal mean plasma concentration 14.9 +/- 2.2 mg l-1) caused a small but significant decrease of plasma potassium. There was no additive or synergistic effect when theophylline was added to fenoterol. It is concluded that inhalation of beta-agonists induces a decrease of plasma potassium, that this effect is relatively more pronounced for fenoterol than either salbutamol or terbutaline, and that it is not enhanced by the concomitant use of theophylline. Theophylline by itself causes a slight decrease in plasma potassium concentration.

Adrenergic beta-Agonists↗
PubMed1987

The effect of changes in dietary sodium content on complaints and clinical parameters of volume depletion in patients with a permanent ileostomy.

In seven patients with an ileostomy the volume and electrolyte composition of ileal effluent and urine were studied at the end of 7-day periods on a free diet (mean total sodium excretion 180 mmol/day) and on diets with a fixed sodium content ranging from 120 to 350 mmol/day. At the same time, complaints were scored and the plasma aldosterone concentration, renal aldosterone excretion, and ileal transmucosal potential difference were determined. On a free diet, all of the patients had one or more complaints. These tended to disappear when intake was increased. Changes in dietary sodium led to only minor changes in the volume and composition of the ileal effluent. Significant associations were found between sodium intake and complaints, the urinary sodium/potassium ratio, plasma aldosterone concentration, and aldosterone excretion. The ileal transmucosal potential difference showed the same tendency. Mean sodium intake on a free diet appeared to be suboptimal. The well-being of many ileostomists can be improved by increasing the dietary sodium intake to a level higher than 250 mmol/day.

Adult↗