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Biomedical subjects

H Beekhuis

Publications and source records attributed to H Beekhuis.

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

Technetium-99m-MAG3 clearance as a parameter of effective renal plasma flow in patients with proteinuria and lowered serum albumin levels.

Although the renal clearance of 99mTc-MAG3 is about 60% of the 131I-hippurate clearance, 99mTc-MAG3 clearance may be useful to estimate ERPF. In one study, however, proteinuria seemed to influence the MAG3/hippurate clearance ratio. In order to establish whether proteinuria or serum albumin level has influence on this ratio, a comparison was made between 99mTc-MAG3 clearance and 131I-hippurate clearance in 14 patients. There was a good linear correlation between MAG3 and hippurate clearance, although the standard error of estimate of ERPF from MAG3 was relatively large, which remained unexplained. No correlation was found between proteinuria and MAG3/hippurate clearance ratio nor between serum albumin level, GFR, FF, ERPF and the MAG3/hippurate clearance ratio. We therefore conclude that there is no correlation between proteinuria and albumin level and the MAG3/hippurate ratio. A reasonable estimation of ERPF with MAG3 can be made in patients with proteinuria and lowered serum albumin levels although the estimation may be less accurate.

Adult↗
PubMed1990

Effect of forced expirations on mucus clearance in patients with chronic airflow obstruction: effect of lung recoil pressure.

Spontaneous mucus clearance and the effect of forced expirations and coughing on mucus clearance were investigated in eight patients with chronic airflow obstruction and low elastic recoil pressure (emphysema group: mean FEV1 45% predicted) and in seven patients with chronic airflow obstruction and normal elastic recoil pressure (chronic bronchitis group: mean FEV1 57% predicted). Mucus clearance was measured in a central and a peripheral lung region by a radioactive aerosol tracer technique. Spontaneous mucus clearance from the peripheral lung region was higher in the patients with emphysema than in those with chronic bronchitis. There was no difference in central mucus clearance between the two groups. Mucus clearance from the peripheral lung region increased significantly during forced expirations and coughing in the patients with chronic bronchitis but not in those with emphysema. It is concluded that in patients with chronic airflow obstruction and regular sputum production spontaneous peripheral mucus clearance is greater in those with decreased elastic recoil pressure. Physiotherapy that includes forced expirations and coughing can enhance mucus clearance in such patients when elastic recoil pressure is normal but is unlikely to be effective when elastic recoil pressure is decreased.

Adult↗
PubMed1990

Noncardiac chest pain: is the esophagus really a frequent source?

The occurrence of esophagus-related noncardiac chest pain was investigated in 22 unselected consecutive patients referred by local cardiologists. The investigations included endoscopy, standard manometry, esophageal scintigraphy, a double-blind placebo-controlled edrophonium provocation test on two occasions (during manometry and scintigraphy), an acid perfusion test, and 24-h ambulatory esophageal pH-monitoring. Nine patients had reflux symptoms; none had dysphagia. Abnormal test results were found in 11 patients. In only three of them was a definite relation between chest pain and the esophagus established: the acid perfusion test was positive in these three, as was 24-h pH-monitoring in two of them. All three had symptomatic reflux. The absence of patient selection and, possibly, the exclusion of biasing during the edrophonium tests are considered to be the most important factors for the finding of only few patients with definite esophagus-related noncardiac chest pain in this study. A prudent approach towards patients with noncardiac chest pain, with regard to the evaluation of an esophageal cause, is recommended.

Chest Pain↗
PubMed1990

Comparison of computed tomography and 57Co-bleomycin scintigraphy in staging the mediastinal lymph nodes of patients with non-small-cell lung cancer.

The value of computed tomography (CT) and of 57Co-bleomycin scintigraphy (57Co-BLM) in staging the mediastinal lymph nodes was compared in 28 patients suffering from non-small-cell lung cancer. The results were assessed against the pathological findings obtained during thoracotomy or mediastinoscopy. CT staging of the mediastinum had a sensitivity of 75%, a specificity of 80%, an accuracy of 79%, a positive predictive index of 60% and a negative predictive index of 89%. 57Co-BLM scintigraphic staging had a sensitivity of 43%, a specificity of 94%, an accuracy of 80%, a positive predictive index of 75% and a negative predictive index of 81%. In this small series these differences were not statistically significant; it thus appears that CT and 57Co-BLM are of equal value in staging the mediastinum. Mediastinoscopy is not contributory in case of a negative CT or 57Co-BLM. A positive CT or 57Co-BLM, however, indicates the need for histological verification of the mediastinal findings.

Adenocarcinoma↗
PubMed1989

57Co-bleomycin scintigraphy for the staging of lung cancer.

The value of Cobalt-57 bleomycin (57Co-BLM) scintigraphy in the detection of lymph node metastases in the hilum and mediastinum was investigated in 132 patients with peripherally located lung cancer. In one half of the patients with metastases, these were visualized. Specificity was 98%. These results were better than those obtained with chest radiography and conventional roentgen tomography. 57Co-BLM scintigraphy is routinely used in the staging of patients with lung cancer, obviating the need for mediastinoscopy.

Adult↗
PubMed1989

Normal cerebrospinal fluid dynamics. A study with intraventricular injection of 111In-DTPA in leukemia and lymphoma without meningeal involvement.

The cerebrospinal fluid flow pattern in seven patients with leukemia or lymphoma, but without prior meningeal or cerebral disease, was studied following introduction of indium-diethylenetriamine pentaacetic acid In-DTPA 111 in a lateral ventricle through an Ommaya reservoir. The time to egress from the ventricular system into the basal cisterns was variable but generally short. One hour after administration, the basal cisterns were clearly visible in all patients. Thereafter, kinetics throughout the cranial and spinal subarachnoid space were consistent. The flow patterns of three patients cured of meningeal dissemination and one patient with mild meningeal leukemia were similar to the normal pattern.

Adolescent↗
PubMed1989

Diagnostic use of angiotensin converting enzyme inhibitors in radioisotope evaluation of unilateral renal artery stenosis.

Iodine-123 hippurate renography, [99mTc]diethylenetriaminepentaacetic acid (DTPA) renography, and [99mTc]dimercapto succinic acid (DMSA) renal scintigraphy were performed before and during angiotensin converting enzyme (ACE) inhibition in a group of 15 hypertensive patients with angiographically "significant" unilateral renal artery stenosis. Visual and quantitative evaluation of the three radioisotope methods before ACE inhibition already disclosed abnormalities suggestive of renal artery stenosis in a high percentage (87%, 60%, and 60%, respectively) in this group of patients, but ACE inhibition further improved the diagnostic yield in all three methods (93%, 86%, and 80%). Iodine-123 hippurate renography was at least as useful as [99mTc]DTPA renography in this respect, while [99mTc]DMSA scintigraphy can be used particularly in segmental stenosis. Despite a large drop in blood pressure after ACE inhibition little adverse reactions were seen and overall renal function was fairly well maintained, the exceptions noted in patients with initially a more impaired renal function.

Adolescent↗
PubMed1988

Value of New York Heart Association classification, radionuclide ventriculography, and cardiopulmonary exercise tests for selection of patients for congestive heart failure studies.

To evaluate the necessity of an objective cardiopulmonary exercise test in the selection procedure of patients for heart failure studies, 50 patients with congestive heart failure New York Heart Association (NYHA) class II and III and a left ventricular ejection fraction less than 40% were subjected to a cardiopulmonary exercise test. The results of the exercise test were compared with the independent clinical estimation of NYHA class and data of measurements obtained at rest. The NYHA classification separated the patients with a mild to moderate impairment of aerobic capacity from patients with a moderate to severe impairment of aerobic capacity very well, but 32% of the NYHA class II patients had a near normal aerobic capacity, and 29% of the NYHA class III patients had a very severe impairment of aerobic capacity, more compatible with NYHA class IV. Only data from exercise measurements showed differences between groups. The determination of maximal aerobic capacity for an objective assessment of patients' performance at exercise is necessary for a proper selection procedure of patients for heart failure studies.

Adult↗
PubMed1988

Retardation of gastric emptying of solid food by secretin.

The effect of secretin at nearly physiologic plasma concentrations on the gastric emptying rate of solid food was studied in 12 healthy men. A 99mTc colloid-labeled pancake was used as the test meal. The gastric emptying rate was measured during 1 h using a dual-headed gamma-camera, and was expressed as the half-time of the emptying curve. To prevent endogenous secretin release, 400 mg of cimetidine was given before the meal. Subjects were studied under three conditions: (1) during infusion of saline; (2) during continuous infusion of secretin, 6.6 pmol/kg.h; and (3) during three intermittent 10-min periods of secretin infusion, 7.6 pmol/kg.h during each period. Both continuous and intermittent infusion of secretin increased half-emptying time, by 133% and 55%, respectively. The plasma secretin concentration in condition 1 was 0.8 pM; plateau concentration in condition 2 was 9.8 pM; and integrated mean concentration in condition 3 was 4.8 pM. It is concluded that secretin at approximately physiologic plasma concentrations retards gastric emptying of solid food in humans.

Adult↗
PubMed1988

57Co-bleomycin scintigraphy in the detection of brain metastases of lung cancer.

57Co-bleomycin scintigraphy was used to detect brain metastases in 46 patients with proven lung cancer and neurological symptoms that could be caused by brain metastases. Scintigraphy was true positive in 19 patients and true negative in 27. In 44 patients without neurological symptoms 57Co-bleomycin scintigraphy was performed to detect silent brain metastases at the time the diagnosis of lung cancer was established. Scintigraphy was false negative in one of these patients and true negative in 43. It is concluded that 57Co-bleomycin scintigraphy is a reliable method to visualize brain metastases in lung cancer patients with neurological symptoms. In our patients it was not useful to detect silent brain metastases of lung cancer.

Adenocarcinoma↗
PubMed1988

Population radiation absorbed dose from nuclear medicine procedures in The Netherlands.

The mean radiation absorbed dose per patient and for the whole population per caput per year in the Netherlands from diagnostic nuclear medicine procedures has been estimated using patient data from 10 large hospitals during either 1984 or 1985. The mean effective dose equivalent and the mean gonad dose equivalent per patient were 2.7 mSv and 1.7 mSv, respectively. Extrapolating these figures to all diagnostic nuclear medicine procedures in the Netherlands, the mean effective dose equivalent and the mean gonad dose equivalent per caput per year were 0.037 mSv and 0.024 mSv, respectively.

Female↗
PubMed1988

Cholecystokinin is a physiological hormonal mediator of fat-induced inhibition of gastric emptying in man.

The effect of cholecystokinin-33 on gastric emptying was studied in eight healthy men. The test meal was a firm custard pudding, labelled with 99mTc-Chelex-100 particles. Gastric emptying rate was measured, using a dual-headed gamma camera, and was expressed as the half time of the emptying curve. Plasma cholecystokinin concentrations were determined by radioimmunoassay. Subjects were studied three times: (i) during infusion of saline; during cholecystokinin infusion, (ii) 0.375 IDU kg-1 h-1 and (iii) 0.75 IDU kg-1 h-1. Furthermore, plasma cholecystokinin was determined after a regular meal. During saline, plasma cholecystokinin increased minimally. After the regular meal it increased from 1.6 to 6.5 pmol l-1 at 30 min, decreasing to 5.3 pmol l-1 at 60 min. During the lower and higher doses of cholecystokinin it increased from 1.0 and 1.4 to 4.5 and 7.3 pmol l-1, respectively. The lower and higher doses significantly (P less than 0.05) increased half emptying time, from 45 +/- 8 to 86 +/- 17 and 198 +/- 50 min, respectively. Cholecystokinin is most likely a physiological hormonal mediator of fat-induced inhibition of gastric emptying.

Adult↗
PubMed1988

Angiotensin converting enzyme inhibition improves diagnostic procedures for renovascular hypertension in dogs.

In renovascular hypertension adaptive mechanisms in the poststenotic kidney are a probable cause of the 20 to 25% false-negative findings during rapid sequence urography or [123I]o-iodohippurate renography. We blocked the renin-angiotensin system in an effort to increase the yield of these diagnostic procedures. Chronically instrumented, salt-depleted conscious dogs were used in which a light (n = 5), moderate (n = 4), or severe (n = 2) renal artery stenosis was induced. Before stenosis 10 of the dogs showed no left-right differences with either diagnostic procedure, and angiotensin converting enzyme (ACE) inhibition did not change this result. Two to 3 weeks after induction of a renal artery stenosis, all dogs showed signs of renovascular hypertension. However, only 50% of the renograms and 22% of the urograms showed differences between the two kidneys indicative of the presence of stenosis. After ACE inhibition, all previously negative test results became positive (abnormal) and previously existing left-right differences became more evidence. Electromagnetically measured renal blood flow on the stenotic side did not change during ACE inhibition (146 +/- 13 vs 145 +/- 21 ml/min), whereas contralateral blood flow showed a distinct increase (207 +/- 18 vs 282 +/- 20 ml/min, p less than 0.01). In conclusion, ACE inhibition markedly improves the sensitivity of rapid sequence urography and hippurate renography in the diagnosis of renovascular hypertension in the two-kidney, one clip Goldblatt hypertensive dog. The effects of ACE inhibition on the handling of the different tracers do not appear to be related to its effects on renal blood flow or systemic blood pressure.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1988

Catabolism of circulating enzymes: plasma clearance, endocytosis, and breakdown of lactate dehydrogenase-1 in rabbits.

Lactate dehydrogenase-1 (EC 1.1.1.27), intravenously injected into rabbits, was cleared with first-order kinetics (half-life 27 min), until at least 80% of the injected activity had disappeared from plasma. Radioactivity from injected 125I-labeled enzyme disappeared at this same rate. Trichloroacetic-acid-soluble breakdown products started to appear in the circulation shortly after injection of the labeled enzyme. Body scans of the rabbits for 80 min after injection of 131I-labeled enzyme revealed rapid accumulation of label in the liver, peaking 10-20 min after injection. Subsequently, activity in the liver declined and radioactivity (probably labeled breakdown products of low molecular mass) steadily accumulated in the bladder. Tissue fractionation of liver, 19 min after injection of labeled enzyme, indicated that the radioactivity was present both in endosomes and in lysosomes, suggesting uptake by endocytosis, followed by breakdown in the lysosomes. Measurements of radioactivity in liver and plasma suggest that the liver is responsible for the breakdown of at least 75% of the injected enzyme. Radioautography of tissue sections of liver and spleen showed accumulated radioactivity in sinusoidal liver cells and red pulpa, respectively. These results are very similar to those for lactate dehydrogenase-5, creatine kinase MM, and several other enzymes that we have previously studied in rats.

Animals↗
PubMed1987

111In-tropolonate labelled platelets; studies in normals and in patients with thrombocytopenia.

Human platelets were labelled with aqueous 111In-tropolonate in comparison with 111In-oxinate. In normals the labelling efficiency with 111In-tropolonate was higher (93% +/- 2%) than with 111In-oxinate (67% +/- 8%) (P less than 0.05). In cases of severe thrombocytopenia, lower labelling efficiencies were obtained. In six normals a mean platelet life of 9 days +/- 3 days and an initial recovery of 59% +/- 15% were obtained. In twelve patients with thrombocytopenia the mean platelet life was 4 days +/- 4 days and the initial recovery was 58% +/- 20%. The absolute uptake of radioactivity in spleen and in liver in both groups are reported.

Blood Platelets↗
PubMed1987

Radionuclide renography to evaluate urodynamically expected upper tract obstruction in patients with meningomyelocele.

Radionuclide renography showed an obstructed pattern in 6 patients with meningomyelocele without dilatation of the upper urinary tract or reflux when the bladder was filled to the volume that during previous urodynamic testing had resulted in an intravesical pressure of 40 cm. water but not when these patients were studied with an empty bladder. Therefore, this study indicates that treatment should be directed at avoiding long-standing intravesical pressure exceeding 40 cm. water in patients with meningomyelocele.

Adolescent↗
PubMed1986

Kinetic analysis of the blood clearance and organ uptake curves of IgG-coated red cells in HLA-typed controls and patients with Wegener's granulomatosis.

Reticuloendothelial function and HLA type were studied in 22 controls and 15 patients with Wegener's granulomatosis (WG). IgG-coated red cells were injected intravenously and half-life times of blood disappearance and liver spleen uptake curves were related to the degree of antibody coating. Erythrocytes with 13,990 molecules of IgG per cell gave biexponential blood disappearance curves and were suitable for measuring splenic reticuloendothelial function. Half-life times thus obtained were not significantly different for individuals with the HLA-DR2 or DR3 phenotype. In WG patients with major disease activity, blood clearance of the injected cells was considerably decreased. Kinetic analysis of blood disappearance and spleen uptake curves revealed that this was partly due to a decrease in reversible trapping of the cells in the spleen. This suggests that a blocking effect of circulating immune complexes on splenic Fc receptors is not likely to be the sole cause of the observed hyposplenism.

Adult↗