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A Struyvenberg

Publications and source records attributed to A Struyvenberg.

At least 19 recordsLinked to original sources
PubMed1992

Insect-sting challenge in 138 patients: relation between clinical severity of anaphylaxis and mast cell activation.

One hundred thirty-eight patients with a previous anaphylactic reaction to a yellow jacket or a honeybee sting, as well as eight volunteers, were subjected to an in-hospital sting challenge. Plasma levels of histamine, tryptase, and prostaglandin D2 (PGD2) during sting challenge were studied in relation to clinical symptoms. Prechallenge levels (mean +/- SD) of histamine, tryptase, and PGD2 were 2 +/- 1 nmol/L, 0.3 +/- 0.3 U/L, and 320 +/- 223 ng/L, respectively. In the volunteers and in none except for one of the nonreacting patients, these levels did not change significantly after challenge. In contrast, mean increases in the group of 18 patients with a mild reaction were significant for histamine and tryptase at one or more time points after the challenge. (Five patients demonstrated no increase in histamine; nine demonstrated no increase in tryptase.) Except for histamine levels in one patient, these increases were considerably more in all 17 patients with a severe reaction, starting from the first anaphylactic symptoms. Fifteen minutes later, peak values were reached of 1275 +/- 2994 nmol of histamine per liter (range, 3 to 12800 nmol/L; median, 11 nmol/L) and 406 +/- 1062 U of tryptase per liter (range, 1.8 to 4400 U/L; median, 17 U/L). This rise in levels inversely correlated with the mean arterial pressure. Plasma levels of PGD2 in severely reacting patients did not differ significantly from those in patients with a mild or no reaction. In conclusion, only 28% of patients with a history of Hymenoptera anaphylaxis developed an anaphylactic reaction after an in-hospital challenge.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaphylaxis↗
PubMed1991

Treatment of uremic anemia with recombinant erythropoietin also reduces the defects in platelet adhesion and aggregation caused by uremic plasma.

In the present study, uremic patients on chronic maintenance hemodialysis were treated with recombinant erythropoietin. Before and after 20 weeks of treatment, platelet adhesion and aggregation were studied with perfusions over a sprayed collagen surface and over matrix of cultured endothelial cells with high tissue factor activity. The influence of the erythropoietin induced raise in hematocrit on platelet transport and adhesion was excluded by performing the perfusions at a standard red blood cell concentration. The present study clearly demonstrates that erythropoietin treatment improves platelet adhesion and aggregation in addition to and independent of its effect on the hematocrit. Studies with control platelets resuspended in plasma of untreated patients showed that a uremic plasma factor reduced adhesion and thrombin- and collagen-dependent aggregation. Patient platelets resuspended in control plasma showed no defects. After erythropoietin treatment, the plasma-induced inhibition of adhesion and aggregation had almost completely disappeared from patient plasma. The beneficial effect of the erythropoietin treatment on uremic hemostasis is therefore twofold. The increase of the red blood cell mass improves transport of platelets, and thus adhesion to the vessel wall. The intrinsic defect due to the presence of an inhibitory toxin in uremic plasma is, in large part, corrected. Improved neutralization of uremic toxins by red blood cells or less production of toxins by better oxygenated tissue might play a role in the observed phenomena.

Adult↗
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].

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Digoxin↗