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Biomedical subjects

S Meijer

Publications and source records attributed to S Meijer.

At least 181 records · Page 10Linked to original sources
PubMed1990

Dissociation of renal vasodilator and natriuretic effects of dopamine during sulpiride infusion in normal man.

The effect of sulpiride on dopamine-induced changes in renal function in man has been investigated. Dopamine dose-response studies were performed in 7 healthy volunteers before and after sulpiride 200 mg i.v. The same investigations were performed in 15 healthy volunteers after pretreatment with the selective alpha-1-adrenoceptor antagonist prazosin (n = 7) and the non-selective alpha-adrenoceptor-blocker phentolamine (n = 8). Infusion of dopamine 0.25 to 8 micrograms.kg-1.min-1 resulted in a dose-dependent increase in effective renal plasma flow (ERPF) and glomerular filtration rate (GFR), and a fall in filtration fraction (FF) in 7 normal volunteers. Sulpiride had no effect on base-line ERPF or GFR and did not influence the dopamine-induced renal vasodilatation in those volunteers. It did cause a fall in the fractional sodium excretion (FENa+%) from 1.7 to 1.38, and shifted the dose-response curve of the natriuretic response to a subsequent infusion of dopamine. Sulpiride enhanced the fall in diastolic blood pressure during infusion of dopamine. In 7 other volunteers pretreated with prazosin, sulpiride did not influence base-line ERPF, GFR or FF or their response to dopamine, but the sodium excretion fell markedly (FENa+% changed from 1.13 to 0.63). Administration of sulpiride to 8 volunteers after phentolamine pretreatment 20 mg.h-1 i.v. in the first hour followed by 10 mg.h-1 i.v. resulted in a fall in sodium excretion (FENa+% from 1.09 to 0.53) without affecting ERPF or FF, and it did not affect the dose-response curve in the subsequent DA infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Soft-tissue uptake of 99mTc-diphosphonate and 99mTc-pyrophosphate in amyloidosis.

This study describes the results of scintigraphy with 99mTc-labeled methylene-diphosphonate (99mTc-MDP) and pyrophosphate (99mTc-PYP) as a noninvasive test for the distribution of organ involvement in five different types of amyloidosis. Scintigraphy with 99mTc-labeled phosphates appeared to be a sensitive noninvasive screening test for the extent and the distribution of organ involvement in systemic AA and systemic AL amyloidosis as well as in local bronchial amyloid, local dermal amyloid, and familial amyloidotic polyneuropathy. Echocardiography, however, was more sensitive for demonstrating cardiac involvement in systemic amyloidosis than 99mTc-MDP or 99mTc-PYP scintigraphy. 99mTc-MDP images showed a better contrast than 99mTc-PYP images, although there was no difference in the extent or the intensity of soft-tissue uptake.

Adult↗
PubMed1990

Successful surgical treatment of parathyroid carcinoma in two haemodialysis patients.

Parathyroid carcinoma is rare, occurring in less than 2-3% of the patients with clinical features of primary hyperparathyroidism. In haemodialysis patients parathyroid carcinoma has only once been described, although secondary hyperparathyroidism in these patients is common. We discuss two female haemodialysis patients with parathyroid carcinoma. Both were treated surgically: in one patient only local excision of the malignancy was performed; the other patient underwent a modified neck dissection on the side of the tumour as well. Physical, biochemical and radiological evaluation for 4-7 years after operation gave no evidence of recurrence of the malignancy.

Adenoma↗
PubMed1990

Lack of effect of lithium on the renal response to DA1-dopamine receptor stimulation by fenoldopam in normal man.

1. The effect of oral lithium (300 mg) on the renal response to the selective DA1-dopamine receptor agonist fenoldopam was investigated in seven normal men. Lithium had no influence on sodium excretion and renal haemodynamics during fenoldopam infusion. The fenoldopam-induced rise in PRA was enhanced in the presence of lithium. We conclude that a previously described interaction between lithium and the dopamine agonist gludopa is not mediated by DA1-dopamine receptors or is confined to higher doses of lithium.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1990

Renal haemodynamic changes in response to moderate hyperglycaemia in type 1 (insulin-dependent) diabetes mellitus.

The prevailing blood-glucose level has been found to influence renal haemodynamics in type 1 (insulin-dependent) diabetes mellitus. In a group of 48 type 1 diabetic patients with normal serum creatinine (less than 120 mumol l-1) and without persistent proteinuria, no relationship was present between blood glucose, corrected to near normoglycaemia (6.8 [6.2 to 7.3] mmol l-1 (median [95% confidence interval]), and glomerular filtration rate (GFR), effective renal plasma flow (ERPF) determined with 125I-iothalamate and 131I-hippuran respectively. GFR tended to increase (2 [-1 to +4] ml min-1 1.73 m-2, 0.05 less than P less than 0.10) and ERPF did not change after a blood glucose rise of 7.9 (7.0 to 8.9) mmol l-1, achieved by an intravenous glucose load in 31 patients. The individual changes in GFR and ERPF were correlated (r = 0.60, P less than 0.005). The changes in GFR were inversely related to baseline blood glucose (r = -0.45, P less than 0.02), but not to baseline GFR. GFR increased (3.5 [0 to +12] ml min-1 1.73 m-2, P less than 0.01) if baseline blood glucose was less than or equal to 6.8 mmol l-1 (n = 16) but ERPF did not. Achievement of near normoglycaemia before measurement of kidney function in type 1 diabetes appears to reduce the influence of variation in glycaemia on renal haemodynamics and thus would improve comparison between and within individuals. Moderate hyperglycaemia can cause a small rise in the glomerular filtration rate.

Adult↗
PubMed1990

Renal and endocrine effects of fenoldopam and metoclopramide in normal man.

The effects of fenoldopam (FD), a selective dopamine-1 (DA1) agonist in doses from 0.05 to 0.50 micrograms/kg/min and of the aselective dopamine antagonist metoclopramide (MCP) on blood pressure (BP), sodium excretion and renal hemodynamics were investigated in 10 healthy volunteers. During FD infusion the diastolic BP fell 9 mm Hg with a rise in heart rate. During combined infusion of FD and MCP no changes in BP occurred. Effective renal plasma flow rose for all doses of FD with a maximal increase of 36% and was not influenced by MCP infusion. Glomerular filtration rate remained unchanged. FD induced an increase in sodium and calcium excretion compared to placebo study, which was abolished by MCP. A marked rise of plasma renin activity during FD infusion was noted, blunted by MCP. MCP induced a marked increase of aldosterone, sustained, but blunted, during subsequent FD infusion, suggesting a DA1-mediated influence on aldosterone secretion. During infusion of FD alone, an increased urinary dopamine excretion was observed. We conclude that FD induces: (1) systemic and renal vasodilation and (2) natriuresis by direct stimulation of DA1 receptors in the proximal tubule, which is (partially) counteracted by a rise of plasma renin activity and subsequently of aldosterone.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1990

Parathyroid localization by 201Tl-99mTc subtraction scintigraphy: results in secondary hyperparathyroidism.

Subtraction scintigraphy with 201Tl and 99mTc for parathyroid localization was performed preoperatively in 13 patients with chronic renal failure and secondary hyperparathyroidism. Twenty of the 37 examined pathological glands were predicted correctly (sensitivity 54%). In 3 patients with recurrent hyperparathyroidism after surgery all pathological glands found at second operation had been detected correctly by subtraction scintigraphy. We conclude that this localization method has a limited value when used prior to first neck exploration in secondary hyperparathyroidism. In persistent hyperparathyroidism after surgery it may play a useful role in localizing missed and ectopic glands.

Adenoma↗
PubMed1989

Association between active Wegener's granulomatosis and anticytoplasmic antibodies.

Autoantibodies reacting with the cytoplasm of granulocytes and monocytes (anticytoplasmic antibodies [ACPAs]) were found in 42 of 45 patients with active Wegener's granulomatosis (WG) (sensitivity, 93%). Specificity was tested in selected groups of patients with closely related diseases. Of 58 patients without a diagnosis of WG, 2 had ACPAs (specificity, 97%). The significance of ACPA titration for assessing or predicting disease activity was evaluated in a 16-month prospective study of 35 patients with WG. Seventeen relapses were observed and all were preceded by a significant rise of the ACPA titer. Anticytoplasmic antibodies are a specific and sensitive marker for active WG; a rising titer is a sensitive marker for the development of a relapse.

Adult↗
PubMed1989

Intraoperative antegrade irrigation in complicated left-sided colonic cancer.

Emergency one-stage surgery for acute, complicated, left-sided colonic cancer can be performed because of intraoperative antegrade irrigation of the large intestine. This procedure was performed in 17 patients: 15 patients with an obstructive, left-sided cancer and two patients with a perforated carcinoma. The age distribution ranged between 57 and 92 years. There were two postoperative septic complications: a small wound abscess and a partial abdominal wall dehiscence. One patient died because of massive upper gastrointestinal bleeding. This method permits the creation of a primary anastomosis in the left colon, obviating the necessity of a coeco- or colostomy, preternatural anus, or an extensive right-sided hemicolectomy. Several surgical interventions are avoided, resulting in a decrease of mortality, morbidity, duration of hospital stay, and costs. Moreover, intraoperative irrigation could be an attractive alternative for the usual preoperative mechanical bowel preparation, which is especially burdensome in elderly patients.

Aged↗
PubMed1989

Acute and cumulative effects of carboplatin on renal function.

Carboplatin, a cisplatinum analogue, has no reported nephrotoxicity in phase I/II studies, assessed by creatinine clearance. We prospectively determined renal function in 10 untreated lung cancer patients with normal baseline renal function, treated with carboplatin 400 mg m-2 day 1 and vincristine 2 mg day 1 and 8 every 4 weeks (max. five cycles) by means of clearance studies with 125I-sodium thalamate and 131I-hippurate to determine GFR and ERPF respectively. Tubular damage was monitored by excretion of tubular enzymes and relative beta 2-microglobulin clearance. During the first course no changes in renal function were seen. After the second course a significant fall in GFR and ERPF started, ultimately leading to a median decrease in GFR of 19.0% (range 6.8-38.7%) and in ERPF of 14% (range 0-38.9%). No increases in the excretion of tubular enzymes or changes in the relative beta 2-microglobulin clearances were seen. We conclude from our data that carboplatin causes considerable loss of renal function. Monitoring renal function in patients treated with multiple courses of carboplatin is warranted.

Aged↗
PubMed1989

Impaired renal hemodynamic but conserved natriuretic response to dopamine in patients with renal disease.

Renal hemodynamics and sodium excretion were determined before and during infusion of dopamine in doses ranging from 0.25 to 8 micrograms/kg/min in healthy volunteers (n = 15) and in patients with renal disease and moderately impaired renal function (n = 21, baseline glomerular filtration rate 34-85 ml/min). While in normal volunteers dopamine resulted in marked renal vasodilation (maximal fall in filtration fraction 24%), in patients with moderately impaired renal function, the renal vasodilatory response to dopamine was impaired (maximal fall in FF 13%) and was found to depend on baseline glomerular filtration rate. Infusion of dopamine in doses of 2 micrograms/kg/min and higher resulted in an increase in urinary sodium excretion, which was comparable for healthy volunteers and patients with renal disease. We conclude that dopamine results in a predominantly efferent glomerular vasodilation and, therefore, may be salutary in lowering intraglomerular hypertension. However, in patients with renal disease the renal hemodynamic response to dopamine infusion is impaired compared to healthy volunteers, while the natriuretic response is maintained.

Blood Pressure↗
PubMed1989

Renal effects of indomethacin in patients with systemic lupus erythematosus.

We evaluated the effect of indomethacin on renal function in a sodium-restricted state in control subjects and in patients with systemic lupus erythematosus (SLE) without major disease activity and with normal or only slightly impaired glomerular filtration rate (GFR). In the patients with SLE indomethacin 150 mg daily induced a fall in GFR of mean 15.8%, while effective renal plasma flow remained constant. Neither effective renal plasma flow, nor GFR changed significantly in the controls. One should be aware that nonsteroidal anti-inflammatory drugs (NSAID) may decrease GFR in SLE, also in patients without disease activity and with normal or only slightly impaired GFR. As effective renal plasma flow remained constant, it is suggested that the indomethacin-induced fall in GFR in SLE is caused by mesangial contraction.

Adult↗