PubMed Health⌕ Search

Biomedical subjects

A J Moolenaar

Publications and source records attributed to A J Moolenaar.

At least 19 recordsLinked to original sources
PubMed1997

Isotope effect in the binding of tritium and 14C-labelled cortisol to corticosteroid-binding-globulin in serum.

We have determined the free cortisol concentration in serum using either the Amicon MPS-1 ultrafiltration-centrifugation method (I) or equilibrium dialysis (II). If procedure I was used we found that [1,2,6,7-3H]-, and [4-14C]cortisol had a lower affinity than unlabelled cortisol for corticosteroid binding globulin (CBG). The binding affinity (Ka) to three separate CBG-containing samples was 8-18 times lower for [1,2,6,7-3H]cortisol and 30-90 times lower for [4-14C]cortisol, when compared with that of unlabelled cortisol. This difference in affinity to CBG was not observed if method II was used for the free cortisol determinations. The observed isotope effect in method I is not caused by unspecific binding to material such as the Amicon MPS-1 chamber or to impurities in the tracer. We suggest that the centrifugation step during ultrafiltration changed the conformation of CBG, thereby reducing its affinity for labelled cortisol. It is concluded that incorrect results will be obtained if radiolabelled is cortisol used for determining the free cortisol content of plasma with the Amicon MPS-1 device.

Artifacts↗
PubMed1993

Expression of P-glycoprotein in relation to clinical manifestation, treatment and prognosis of adrenocortical cancer.

The presence of P-glycoprotein, associated with multiple drug resistance and present in the normal adrenal cortex, was studied in 15 cases of adrenocortical carcinoma. P-glycoprotein was found in eight tumours; no correlation was found with clinical presentation, steroid production or histological index. 10 patients received mitotane. Remarkably, 3 patients with P-glycoprotein-positive tumours achieved complete remission. On the other hand, 2 patients with P-glycoprotein-negative tumours showed progression of the disease despite mitotane treatment. These findings suggest that the expression of P-glycoprotein in adrenocortical carcinoma is not related to clinical manifestations, steroid production, histological index or response to mitotane therapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Semiquantitative assessment of hirsutism in Dutch women.

Many doctors frequently encounter hirsute patients. Quantification of hair growth may be useful for diagnosis and follow-up. To establish the reference range for distribution and density of hair in females, and to determine the regions yielding the best discrimination between normal and hirsute women, we studied the distribution and density of terminal hair on 12 body regions assessed on a scale of 0-4. Prospectively, 81 healthy female volunteers and 71 hirsute patients of child-bearing age and Dutch ancestry, who were not receiving medication, and who had not had a recent pregnancy were studied. The reference hair pattern was established for each body region, and the threshold value yielding the highest sensitivity and specificity to evaluate hirsutism was calculated. None of the women in the reference population displayed a score of more than 1 for chin, upper back, upper abdomen and upper arm, or more than 2 for upper lip, side-burns, chest, lower back, lower abdomen, thighs or forearm. The best discrimination between the reference and hirsute populations was obtained with the sum of the scores for four regions: upper lip, chin, lower abdomen and thighs. Independent assessment of hair growth by two investigators revealed excellent agreement. We conclude that a score of more than 1 for chin, upper back, upper abdomen and upper arm, or more than 2 for upper lip, side-burns, chest, lower back, lower abdomen, thighs or forearm is abnormal for Dutch women, and that assessment of hair growth on the upper lip, chin, lower abdomen and thighs is the most suitable way to evaluate hirsutism.

Abdomen↗
PubMed1993

Free cortisol in serum assayed by temperature-controlled ultrafiltration before fluorescence polarization immunoassay.

A method is described for a temperature-controlled ultrafiltration procedure to measure free cortisol in serum. A special thermometer with a sensor was developed, measuring the temperature directly in the ultrafiltration device. The sensor is screwed on the axis of the centrifuge rotor, and the centrifuge is placed in a temperature-controlled box so that the temperature of the sample is kept at 37 degrees C +/- 0.1 degrees C. The overall CV of the free cortisol assay ranges from 2.2% to 11.4%, of which the ultrafiltration contributes only 2.2-3.6%. Increasing amounts of cortisol-binding protein, as found in women using estrogen-containing oral contraceptives, have minor but significant effects on the free cortisol concentrations in serum. Serum free cortisol concentrations in a reference population (n = 114; central 95 percentiles) were 12-43 nmol/L (4-9.5% of total cortisol); in the group of the oral-contraceptive users (n = 27), the reference interval was 11-53 nmol/L (1.5-4.5%).

Blood Preservation↗
PubMed1992

The distribution of o,p'-DDD (mitotane) among serum lipoproteins in normo- and hypertriglyceridemia.

We found that the distribution of the lipophilic chemotherapeutic agent o,p'-DDD (mitotane) among serum (lipo)proteins was altered in hypertriglyceridemia, with relatively more o,p'-DDD accumulating in the chylomicron and very-low-density lipoprotein (VLDL) fraction. Intralipid, an artificial chylomicron emulsion, or isolated VLDL could extract o,p'-DDD from the other serum (lipo)proteins. There was an inverse relationship between the relative amount of o,p'-DDD found in the fraction exhibiting a density of less than 1.006 g/ml (chylomicrons plus VLDL) and the relative amount observed in the LDL or HDL fractions of serum. Our results indicate that hypertriglyceridemia may impede the entry of o,p'-DDD into the brain or the adrenals. For therapeutic monitoring of o,p'-DDD levels in severe hypertriglyceridemia, we recommend that the chylomicron and VLDL fraction first be removed from the serum by ultracentrifugation.

Adrenal Cortex Neoplasms↗
PubMed1992

Influence of perinatal conditions on C-reactive protein production.

C-reactive protein rises in blood in an acute-phase response in adults, children, and neonates. In a prospective study of the influence of perinatal asphyxia, premature rupture of membranes, hyperbilirubinemia, and respiratory distress syndrome on levels of C-reactive protein in the neonate, we detected no confounding effect on the rise of C-reactive protein level in infants with these pathologic perinatal conditions, as compared with the results of a control group.

C-Reactive Protein↗
PubMed1992

A case of recurrent adrenocortical carcinoma, with observations on long-term o,p'-DDD therapy and complications.

This report describes a patient with a recurring, one stemline-aneuploid, adrenocortical carcinoma. The condition showed a number of unusual characteristics over a period of 22 yr. It changed from a biochemically functioning, low-grade malignant tumour into a non-functioning malignancy with pronounced mitotic activity, accompanied by an ovarian carcinosarcoma 1 yr before death. Quality of life was reasonable for many years despite chemotherapy, consisting of a total of almost 10 kg of o,p'-DDD administered over a period of 8 yr, and the subsequent side effects (e.g. low T4; increased bleeding time). A reduced mineralocorticoid activity, induced by o,p'-DDD, was reversed after discontinuation of o,p'-DDD treatment. During o,p'-DDD administration the substitution requirements for both hydrocortisone and fludrocortisone acetate increased, leading to periods of hypoadrenocorticism with prerenal uraemia.

Adrenal Gland Neoplasms↗
PubMed1991

Interaction of ORG 10172, a low molecular weight heparinoid, and digoxin in healthy volunteers.

Potential pharmacokinetic and pharmacodynamic interactions between a new low molecular weight heparinoid Org 10172 (bolus injection of 3250 anti-Xa units) and digoxin (0.25 mg once daily for 8 days) were studied in 6 healthy male volunteers using an open, randomised three-way cross-over design. Digoxin produced a slight increase in clearance of anti-Xa activity from 4.3 to 4.8 ml.min-1, while plasma antithrombin and thrombin generation inhibiting (TG1) activity remained unchanged. Digoxin did not affect the actions of Org 10172 on the clotting tests. In the presence of Org 10172 there was a reduction in the AUC of digoxin during one dosing interval after the seventh digoxin tablet from 20 to 17 ng.ml-1.h, and a significant reduction in the average serum digoxin concentration. Since renal digoxin clearance was not significantly changed this probably might be due to a change in the non-renal clearance of digoxin. Atrio-ventricular node conduction, as measured by PR-time intervals, remained unchanged during all three treatments. In conclusion, although the pharmacokinetics of Org 10172 and digoxin were slightly changed by the combination, it is probably safe to administer Org 10172 and digoxin simultaneously. The clinical relevance of the slight decrease in plasma anti-Xa activity levels cannot yet be defined.

Administration, Oral↗
PubMed1991

Mitotane increases the blood levels of hormone-binding proteins.

In 3 patients with adrenocortical carcinoma the effects of long-term mitotane therapy on the serum levels of three hormone-binding globulins and vitamin D-binding protein were studied. Within the first month of treatment cortisol-binding globulin increased two to three times, in close correlation with sex hormone-binding globulin. The rises in thyroxine-binding globulin and vitamin D-binding protein were considerably less. Elevated cortisol-binding protein appeared to be associated with increased binding of cortisol, whereas the binding of thyroxine and vitamin D remained below normal. Binding proteins returned to normal in 2 patients within a year after mitotane discontinuation. This phenomenon of hormone-binding protein enhancement invalidates the use of total serum hormone levels to monitor the effects of mitotane on endocrine function and could provide an explanation for the increased cortisol substitution requirement during mitotane therapy.

Adrenal Cortex Neoplasms↗
PubMed1990

Transplacental passage of digoxin in severe Rhesus immunization.

Maternal and umbilical vein digoxin concentrations were determined in 16 mothers and fetuses with severe Rhesus-D disease, eight with, and eight without prior digitalization of the mother, when umbilical cord puncture was performed for diagnosis and intrauterine blood transfusion. In the eight patients without digoxin treatment, the digoxin concentrations in both the mother and the umbilical vein were below the limit of detection (less than 0.3 nmol/l). In the other eight patients digitalization of the mother was started 24-48 hours before the first umbilical cord puncture. The maternal and umbilical vein digoxin concentrations were determined on 26 occasions. Except for two instances, digoxin concentrations in the umbilical vein were always below 1 nmol/l. The mean ratio of maternal to fetal digoxin concentrations before initial transfusion was 2.51 ( +/- ISD = 1.47) and before later transfusions 1.67 ( +/- ISD = 0.61). The differences in mean ratios between initial and later transfusions are not significant (p = 0.16). The mean ratio for the total group was 1.93 ( +/- ISD = 1.01). There was no correlation between the maternal to umbilical vein digoxin ratio and either gestational age or umbilical venous hematocrit. The results of our study indicate that the therapeutic effect of transplacental digitalization in severe Rhesus disease is questionable and that a multicentre randomized trial would be necessary to evaluate whether this treatment is of benefit.

Blood Transfusion, Intrauterine↗
PubMed1990

Iodine-123-metaiodobenzylguanidine scintigraphy in patients with chemodectomas of the head and neck region.

While studying the uptake of iodine-123-metaiodobenzylguanidine ([123I]MIBG) in chemodectomas, we coincidentally detected catecholamine secreting tumors in 5 out of 14 patients. In three of these cases, a norepinephrine secreting abdominal paraganglioma was subsequently removed. One patient had a norepinephrine secreting chemodectoma and one had a dopamine secreting chemodectoma. Prior to [123I]MIBG imaging and urinary catecholamine measurements, endocrine activity was suspected in only one of these five patients. Apart from these five cases, two other patients showed elevated catecholamine secretion and abnormal abdominal [123I]MIBG concentrations. However, these two patients were not surgically explored, because of normal computed tomography (CT) and magnetic resonance (MRI) studies. We suspect that catecholamine-secreting tumors are more common in patients with chemodectomas than is assumed in the literature, and we therefore recommend urinary catecholamine screening for all patients with chemodectomas. In case of elevated catecholamine secretion, MIBG scintigraphy is indicated.

3-Iodobenzylguanidine↗
PubMed1989

Low dose aminoglutethimide without hydrocortisone for the treatment of advanced postmenopausal breast cancer.

One hundred and one postmenopausal patients with advanced breast cancer were enrolled in a randomized phase II clinical trial to investigate the clinical and hormonal response to aminoglutethimide administered at daily doses of 2 x 125 mg, 3 x 125 mg or 2 x 250 mg, with no addition of hydrocortisone. Among 71 evaluable patients 25% showed objective tumor response (three complete, 15 partial), at all three dose levels and irrespective of the major tumor site. Previous treatment with Tamoxifen had been successful in 75%. Out of the 18 responding patients 10 had estrogen receptor positive, four had estrogen receptor negative tumors; the receptor status was unknown in four other patients. Progression-free interval was more than 700 days in 50% of the responders. Drowsiness caused early drug withdrawal in one patient. Side-effects were very mild, comparing favorably with standard therapy of 250 mg aminoglutethimide q.i.d. plus hydrocortisone. Plasma estrogen levels were reduced by all doses to the same 50% or less as in patients on standard treatment. In nine out of 27 patients a further decrease of estrone levels could be monitored with clinically improved results in five. Plasma cortisol and mineralocorticoids remained normal throughout more than 6 months. The original role of hydrocortisone administration to suppress a reflex rise of ATH in 'medical adrenalectomy' with standard dose aminoglutethimide is no longer tenable. Further phase III comparative clinical results pending, low dose aminoglutethimide as an aromatase inhibitor may at present be considered as an appropriate second-line endocrine treatment with low toxicity and expense.

17-alpha-Hydroxyprogesterone↗