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Biomedical subjects

H Doorenbos

Publications and source records attributed to H Doorenbos.

At least 37 records · Page 2Linked to original sources
PubMed1989

The usefulness of a sensitive thyrotrophin assay in the fine adjustment of thyroxine therapy following ablation for carcinoma.

The usefulness of FT4 and FT3 measurements as an index of adequate thyroxine treatment in differentiated thyroid cancer was evaluated in 25 athyreotic patients on two occasions with an interval of at least 6 months. The determinations were combined with a TRH test. The TSH measurements were performed using a sensitive immunoassay. The great interindividual differences in absorption and metabolism of thyroxine made the measurements of FT4 and FT3 unsuitable for fine adjustment of thyroxine substitution therapy. When all patients are divided into 4 categories according to their TRH test (1: delta TSH less than or equal to 1 mU/l; 2: greater than or equal to 1 less than or equal to 4 mU/l; 3: greater than 4 mU/l and 4: basal TSH greater than or equal to 6 mU/l), there is a considerable overlap between these categories in relation to FT4 and FT3. In the second TRH test all patients were found to belong to the same category when their thyroxine dose had not been changed. A basal TSH level below 0.30 mU/l suggests nearly complete suppression of TSH secretion. However, a TRH test is necessary to allow a definite conclusion to be drawn. It is argued that complete suppression of TSH is not necessarily desirable in patients with treated thyroid carcinoma. From the results of our study it would seem advisable to use the TRH test once to adjust the thyroxine dose in such a manner that subnormal basal TSH is achieved as in the second category. Once the dosage has been established, a determination of basal TSH suffices in follow-up.

Adult↗
PubMed1988

Effects of short-term high dose intake of evening primrose oil on plasma and cellular fatty acid compositions, alpha-tocopherol levels, and erythropoiesis in normal and type 1 (insulin-dependent) diabetic men.

In addition to their usual diet, nine Type 1 (insulin-dependent) diabetic men and ten male control subjects took 20 g d, alpha-tocopheryl acetate enriched evening primrose oil (14.45 g 18:2c,omega 6, 1.73 g 18:3c,omega 6, 400 mg d,alpha-tocopheryl acetate) daily for one week. At start, diabetic patients had more 14:0, 15:0 and 18:2c,omega 6, and less 16:0, 16:1c,omega 7, 18:1c,omega 7, 18:3c,omega 6, 20:3c,omega 9, 20:3c,omega 6, 20:4c,omega 6 and 22:6c,omega 3 in plasma, erythrocytes and/or platelets. Furthermore, they had lower 16:1c,omega 7/16:0, 18:1c,omega 7/16:0, and 20:4c,omega 6/20:3c,omega 6 ratios and a higher 20:3c,omega 6/18:3c,omega 6 ratio. In diabetic patients, alpha-tocopherol levels in erythrocytes were lower, whereas those in plasma were normal. In both groups, oil intake changed fatty acid profiles. Most markedly, 20:3c,omega 6 increased, whereas the ratios 20:3c,omega 6/18:3c,omega 6 and 20:4c,omega 6/20:3c,omega 6 decreased. 20:4c,omega 6 increased in control subjects, but not in diabetic patients. Erythrocytes and platelets responded differently in their fatty acid profiles. alpha-tocopherol rose in plasma and, although less for diabetic patients, in erythrocytes. In diabetic patients as well as in control subjects, erythrocyte count, haemoglobin level, mean corpuscular haemoglobin content and concentration increased and glycosylated haemoglobin percentage decreased without an apparent decline in blood glucose levels. Plasma beta-thromboglobulin and platelet factor 4 decreased, especially in diabetic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Hypothyroidism leads to more small-sized platelets in circulation.

The effect of induced hypothyroidism on platelet count and platelet volume distribution was studied in twelve athyreotic patients. After a two weeks withdrawal of triiodothyronine supplementation, platelet count and the ratio between platelet and red cell count were increased in all patients. Furthermore, mean platelet volume was declined and platelet distribution width was risen. Thus, hypothyroidism appears to increase the number of circulating platelets, especially the smaller ones.

Adult↗
PubMed1987

Malignant struma ovarii treated by ovariectomy, thyroidectomy, and 131I administration.

A 36-year-old woman presented with an intraperitoneally disseminated malignant struma ovarii, diagnosed by histopathology and 131I scintigraphy. The serum thyroglobulin level was elevated, and immunoperoxidase staining for thyroglobulin was positive for disease both in the tumor cells lining the follicles and in the colloid. The patient was treated successfully by a bilateral ovariectomy followed by a total thyroidectomy and administration of radioactive iodine. The clinical behavior and the presence of thyroglobulin in both serum and tumor tissue demonstrate the similarity between neoplastic thyroid tissue in the ovary and in the thyroid gland.

Adult↗
PubMed1987

Rapid changes in serum, plasma and erythrocyte lipid compositions, and serum transaminase levels during continuous enteral hyperalimentation by carbohydrates alone.

Twelve normal men received twice their estimated basal energy requirement by a carbohydrate solution via a nasogastric catheter during 48 hours, followed by a seven-hour fast. Subsequently, in nine of them 0.5 mg epinephrine was given subcutaneously under ongoing fasting. During hyperalimentation, serum triglycerides, phospholipids, total and free cholesterol, phospholipids/free cholesterol ratio, and plasma free fatty acids decreased, whereas the percentage of free cholesterol increased. During fasting and subsequent epinephrine administration triglycerides and free fatty acids rose without reaching basal levels. Plasma and red blood cell (RBC) fatty acid composition already changed from two hours after the start of the feeding. Most markedly, a steady decrease in RBC 18:2c, omega 6, amounting to more than 17% of the basal value at the end of the observation period was found. Neither in plasma, nor in RBC a concomitant appearance of 20:3c, omega 9 was seen. In RBC, the relative amounts of the saturated fatty acids increased, whereas those of monounsaturated and polyunsaturated fatty acids decreased. RBC content of total fatty acids decreased and that of cholesterol increased. The ratios 16:1c, omega 7/16:0 and 18:3c, omega 6/18:2c, omega 6 in plasma, and 20:3c, omega 6/18:2c, omega 6 in plasma and RBC increased, whereas those of 18:1c, omega 7/16:1c, omega 7 and 20:3c, omega 6/18:3c, omega 6 in plasma decreased. After 48 hours feeding serum glutamic pyruvic transaminase and glutamic oxaloacetic transaminase levels were moderately increased and rose further during fasting. Thus, continuous enteral hyperalimentation by carbohydrates alone rapidly induces profound changes in serum-, plasma-, and RBC lipid compositions and serum parameters of hepatic function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Changes in fatty acid profiles of plasma, erythrocytes and polymorphonuclear leukocytes in induced hypothyroidism in man: indirect evidence for altered delta 6 desaturase activity.

Thirteen patients who were athyreotic as a consequence of ablation treatment for well-differentiated thyroid cancer were studied during triiodothyronine supplementation, and subsequently at the end of a two weeks withdrawal of this medication. Serum and plasma lipid concentrations, erythrocyte cholesterol content and plasma and erythrocyte total fatty acid patterns were measured. In addition, total fatty acid profiles of polymorphonuclear leukocytes of eight patients and scanning electron microscopic studies of erythrocytes of nine patients were made. We observed an increase of the serum concentrations of total and unesterified cholesterol and phospholipids in all patients. Except for two, all patients showed an increase in the serum triglyceride concentration. The relative amounts of 18:2c,omega 6 rose and those of 20:3c,omega 6 fell in all studied compartments. In addition, the relative amounts of all other omega 6 fatty acids, 22:6c,omega 3, 20:3c,omega 9, 16:0, 18:0, and total saturated fatty acids decreased in plasma, whereas the levels of all monounsaturated fatty acids increased in the erythrocytes. The level of 20:3c,omega 9 rose in the erythrocytes and the 20:3c,omega 9/20:4c,omega 6 ratio rose in the polymorphonuclear leukocytes. The erythrocyte total fatty acids and cholesterol content and their ratio did not change, nor was any alteration seen in the red cell morphology by scanning electron microscopy. This study reveals that the induction of hypothyroidism in man changes fatty acid patterns of plasma, erythrocytes and polymorphonuclear leukocytes. The nature of these alterations suggests especially a disturbance in the delta 6 desaturase activity. The data point to the possibility of a derangement of eicosanoid synthesis in hypothyroidism.

Adult↗
PubMed1986

Increase of plasma and red cell cholesterol sulfate levels in induced hypothyroidism in man.

Plasma and erythrocyte cholesterol sulfate-, erythrocyte cholesterol-, and serum unesterified- and total cholesterol levels of ten athyreotic thyroid cancer patients were measured during triiodothyronine supplementation, and subsequently at the end of a two weeks withdrawal of this medication. The results showed that in the hypothyroid state all above mentioned parameters increased except for the erythrocyte cholesterol level, which remained unchanged. The interrelationships between these parameters, and the exchange mechanism of cholesterol sulfate between plasma and erythrocytes are discussed.

Adult↗
PubMed1986

Effects of isoprenaline and terbutaline on urinary excretion of histamine and its two main metabolites in systemic mastocytosis.

Both short-term and long-term effects of the beta-sympathomimetic drugs isoprenaline and terbutaline on the urinary excretion of histamine and its two main metabolites were evaluated in patients with systemic mastocytosis. In a short-term study isoprenaline and terbutaline were given intravenously during five hours to three and two patients, respectively. Compared with placebo infusion Nt-methylhistamine excretion fell during terbutaline administration, whereas during isoprenaline no changes were observed. In a long-term study three patients received a treatment with orally administered terbutaline for 24 days. In one patient a slight reduction of the excretion of the histamine metabolites was found. In another patient the excretion of histamine and its metabolites decreased especially during the eight days observation period after the end of the treatment. In this study we saw occasionally large and rapid changes occurring simultaneously in all three urinary parameters of histamine release. In conclusion, terbutaline can reduce histamine release in systemic mastocytosis. However, because of the small symptomatic and biochemical effects found in our patients, the clinical significance of beta-sympathomimetic drug treatment in this disease has yet to be established.

Adult↗
PubMed1985

Mechanism of adrenal suppression by high-dose medroxyprogesterone acetate in breast cancer patients.

To investigate the mechanism of adrenal suppression by high-dose MPA, we performed direct and indirect stimulation tests in postmenopausal women with disseminated breast cancer who were receiving MPA and in a postmenopausal breast cancer control group. A partial adrenal insufficiency was found during Synacthen stimulation, confirmed by a slight increase of 11-desoxycortisol after metyrapone, despite a sufficient rise in ACTH levels. Peak levels of androstenedione and 17-OH progesterone after Synacthen correlated with those after metyrapone. Peak cortisol levels after Synacthen also correlated with the sum of cortisol and 11-desoxycortisol values after metyrapone, indicating the presence of a maximum adrenal response and a sufficient rise of endogenous ACTH after metyrapone. As the peak levels of cortisol and androstenedione were highly correlated with baseline values, a short Synacthen stimulation test may give a good indication as to whether adrenal suppression by MPA is adequate. The adrenal androgen androstenedione is the precursor of the main postmenopausal oestrogen, oestrone. In this way, adrenal suppression may constitute an important therapeutic effect of high-dose MPA.

17-alpha-Hydroxyprogesterone↗
PubMed1985

Endocrine effects of medroxyprogesterone acetate: relation between plasma levels and suppression of adrenal steroids in patients with breast cancer.

The elimination of adrenal steroids by adrenalectomy or medical treatment has been one of the mainstays in the palliative treatment of patients with disseminated breast cancer. Recently, the effects of progestins on adrenal function has become the subject of renewed interest. To find a relation between plasma levels of medroxyprogesterone acetate (MPA) and adrenal suppression in breast cancer patients, we compared a group of 41 postmenopausal patients with disseminated or inoperable breast cancer, treated with oral MPA, with a control group of 28 postmenopausal breast cancer patients without treatment. To obtain MPA plasma levels in the lower range, 13 patients initially received 300 mg of MPA daily (Group 1), six of whom were subsequently treated with 600 mg (Group 2). Group 3 comprised 37 patients treated with 900 mg of MPA. All of the parameters studied varied widely. Only in Group 3 patients were the MPA levels higher and the levels of cortisol, androstenedione, DHAS, and estrone lower than those in Group 1 patients. All steroid levels in Group 3 were significantly below control values. Considering all data, a negative but weak correlation was found between MPA levels and cortisol (R = -0.55), androstenedione (R = -0.58), and dehydro-epi-androsterone sulfate (R = -0.40), but not for MPA and estrone, indicating better adrenal suppression by higher MPA dosage and plasma levels. However, suppressed cortisol concentrations did not predict sufficient MPA dosage in all patients because low cortisol was not always associated with high MPA levels. A positive relation existed between the levels of androstenedione and estrone, which shows that suppression of these adrenal androgens may result in suppression of plasma estrone. This may be of additional therapeutic benefit in breast cancer patients.

Adrenal Glands↗
PubMed1984

The plasma and erythrocyte fatty acid composition of poorly controlled, insulin-dependent (type I) diabetic patients and the effect of improved metabolic control.

Analysis of the plasma and erythrocyte fatty acid composition of poorly controlled, insulin-dependent (type I) diabetic patients revealed a low level of 18:3c, omega 6, 20:3c, omega 6, 22:6c, omega 3 and total polyunsaturated fatty acids, and a high level of 18:0 and total saturated fatty acids. Improvement of diabetic control, achieved by treatment with continuous subcutaneous insulin infusion coincided with an increase of arachidonic acid and a normalization of total polyunsaturated fatty acids, with a concomitant decrease of total saturated fatty acids and total monounsaturated fatty acids, especially 18:1c, omega 9. The results of this study can be important for the dietary advice to poorly controlled, diabetic patients.

Adult↗