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Biomedical subjects

C Beckers

Publications and source records attributed to C Beckers.

At least 55 records · Page 3Linked to original sources
PubMed1989

Interference in thyrotropin (TSH) determination: falsely elevated TSH values in a transplanted patient.

We report a falsely elevated TSH value as determined by an immunoradiometric assay. The patient, a thyroidectomized woman on substitutive therapy, underwent a kidney transplantation. She was treated for transplant rejection with OKT 3 (Orthoclone), a mouse monoclonal antibody. The discrepancy between the TSH value (TSH-Riabead II, Abbott) and the thyroid hormones level led us to suspect the presence of antimouse antibodies in the serum of this patient. Indeed, human immunoglobulins directed against mouse IgG2a and IgG2b were detected. We repeated-the TSH determination in the presence of normal mouse serum (NMS) and obtained a true TSH value. Upon fractionation of the serum with protein-A chromatography, the falsely elevated TSH immunoreactivity was detected in the IgG fraction.

Animals↗
PubMed1989

Decreased serum TBG concentration in the face of normal T4-binding capacity in patients on hemodialysis.

Serum TBG concentrations were evaluated in 34 patients on regular hemodialysis. Mean serum TBG level measured by two different radioimmunoassays was markedly decreased (1.24 +/- 0.08 mg/dl - normal limits 1.6-2.4 mg/dl). Twenty-seven (79%) patients had values below 1.6 mg/dl, which contrasted in 21 of them with a lack of reciprocal elevation of T3RU values. By contrast, T4-binding capacity of TBG measured in 14 patients with low TBG concentration was normal, suggesting that the low TBG values were an artefact resulting from an altered immunoreactivity of the protein. In 2 patients with low TBG while on hemodialysis, TBG levels increased significantly after renal transplantation. This suggests that the "low TBG syndrome" (altered immunoreactivity in the face of normal T4-binding capacity) observed in patients on chronic hemodialysis is a consequence of uremia.

Adolescent↗
PubMed1988

Assessment of left ventricular diastolic function in patients receiving anthracycline therapy.

Abnormalities in left ventricular filling have been described as an early finding in coronary artery disease and in cardiomyopathy. The present study was undertaken to determine whether impaired diastolic function may be an early sign of anthracycline cardiotoxicity. Radionuclide left ventricular curves of 30 treated patients were compared with the curves of 17 normal, agematched, volunteers. The curves were analyzed for ejection fraction, peak filling rate (normalized for end diastolic counts and for stroke counts), time to peak filling rate and filling fraction in the first third of diastole normalized for cycle length. In 20 patients (Groups A and B), we analyzed the radionuclide ventriculography preceding the decrease of systolic function or a clinical congestive heart failure. In ten patients (Group C) who ended a treatment regimen without systolic dysfunction or clinically evident cardiotoxicity, we analyzed the ventriculography at the end of the therapy. Among the diastolic indexes, only the first third filling fraction was abnormal in a minority of the patients (6/20 in Groups A and B). Our findings suggest that diastolic dysfunction is uncommon in anthracycline treated patients prior to systolic dysfunction.

Adult↗
PubMed1988

Decreased TSH response to TRH induced by amiodarone.

In order to test the reactivity of TSH to TRH during amiodarone treatment we investigated 7 hypothyroid subjects treated with 50 micrograms T3/day. A TRH test (200 micrograms iv) was performed before and after 6 weeks of treatment with 400 mg amiodarone/day. Amiodarone treatment induced a significant increase in serum total and free T3 (from 2.17 +/- 0.13 to 3.55 +/- 0.58 nmol/l and from 5.6 +/- 0.61 to 9.46 +/- 1.41 pmol/l). Basal TSH levels were significantly decreased and the maximal stimulation of TSH 20 min after TRH injection was only 20.0 +/- 3.3 mU/l during amiodarone treatment compared with 61.4 +/- 10.4 mU/l before treatment. These results indicate that in hypothyroid patients treated with amiodarone, the TSH response to TRH is blunted and that this is likely to be related to the higher total and free T3 levels or to a direct effect of amiodarone at the pituitary level.

Amiodarone↗
PubMed1988

[The role of iodine in goitrogenesis].

Iodine deficiency remains the main goitrogenic factor which affects not only many developing countries, but still many areas in Western Europe. Iodine excess is much less often responsible for the development of goiter, but through the iodine-induced immune disturbances within the thyroid, could on a long run, appear also goitrogenic.

Goiter↗
PubMed1988

Resting and hypercapnic rCBF in patients with unilateral occlusive disease of the internal carotid artery.

Regional cerebral blood flow was measured by the 133Xe inhalation technique in 15 patients with severe unilateral internal carotid artery stenosis (75%) or occlusion, and in the absence of evidence of any sign of occlusive disease in other main afferent cerebral arteries. A comparison with normal subjects showed that lowered resting flow in both hemispheres was a common finding in all patients. Interhemispheric asymmetry was present only in patients with occlusion and the precentral, posterior temporal, and occipital regions were the most seriously affected. The CO2 reactivity was substantially reduced in both hemispheres of all stenotic and occluded patients, but occluded patients showed an increased reduction of CO2 reactivity only in the ipsilateral hemisphere. In addition to an hypothetical age effect, the atherosclerotic involvement of the cerebral vascular system leads to a reduction of flow and loss of CO2 reactivity in both hemispheres. In this context, the collateral supply capacity is not overloaded in case of a unilateral severe stenosis but fails in case of a unilateral occlusion of the internal carotid artery. A suitable estimate of the blood flow reduction as a result of occlusion is made by the hemispheric and regional laterality indices applied in resting and hypercapnia conditions. These indices could be used as indicators for endarterectomy or bypass surgery as well as a sensitive means for appreciating cerebral blood flow response to treatment.

Adult↗
PubMed1987

Ejection fraction response to upright exercise in hypertension: relation to loading conditions and to contractility.

The respective roles of peripheral and myocardial determinants of exercise ventricular performance were studied in 10 normal volunteers and in 9 mildly hypertensive patients without evidence of coronary disease. Hemodynamic measurements and equilibrium blood pool scintigraphy were simultaneously performed at rest and during maximal upright exercise. In hypertensive patients, mean systolic and diastolic blood pressure were, respectively, 199 +/- 23 and 102 +/- 12 mm Hg at rest, and 271 +/- 28 and 113 +/- 8 mm Hg at peak exercise. Ejection fraction response to exercise was normal (increase by more than 5%) in 4 hypertensive patients (normal hypertensive group: 63 +/- 4 to 77 +/- 6%) and in volunteers (65 +/- 3 to 78 +/- 4%) and abnormal in 5 hypertensive patients (abnormal hypertensive group: 66 +/- 6 to 58 +/- 10% at peak exercise). The abnormal response in the abnormal hypertensive group was not due to an inadequate decrease in systemic vascular resistance during exercise. By contrast, the ratio systolic blood pressure/end-systolic volume, an index of contractility, decreased by 2.3 +/- 4.9 in the abnormal hypertensive group, whereas it increased by 9.8 +/- 9.1 in the normal hypertensive group and by 7.3 +/- 2 in volunteers. Thus, abnormal exercise ejection fraction response in mild hypertension was not related to increased afterload but rather to intrinsic myocardial factors.

Adult↗
PubMed1987

Trends in thyroid imaging.

The master choice for thyroid imaging remains the radioiodine thyroid scan with 123I or 99mTc. 131I has to be reserved for the follow-up of thyroid cancer only. Ultrasound may remain useful in certain situations but it does not integrate as it is the case with the radioisotopic scan together with morphological and functional information.

Humans↗
PubMed1987

Cell cycle analysis by flow cytometry in an antibody secreting cell line.

This presentation reports on the routine use of flow cytometric techniques in suspension cultures. As a model system an antibody secreting mouse hybridoma cell line was used to monitor antibody production (a Bromodeoxyuridine specific antibody) and proliferative status as obtained by flow cytometry (FCM) and cell counting.

Animals↗
PubMed1986

Alteration of left ventricular diastolic filling in hypertensive patients: effects of nitrendipine and atenolol.

This study was undertaken to determine the chronic effects of a long-acting calcium-channel blocker (nitrendipine) on resting left ventricular filling abnormalities in ten patients with essential hypertension. Radionuclide left ventricular curves of these hypertensive patients were compared with the curves of twelve normal volunteers and of eight asymptomatic older patients. The curves were analyzed for ejection fraction, peak filling rate (normalized for end-diastolic counts and for stroke counts), time to peak filling rate and filling fraction in the first-third of diastole normalized for cycle length. Heart rate and ejection fraction were similar in both control groups and hypertensive patients before and after nitrendipine. Before nitrendipine, diastolic filling parameters were significantly different in the hypertensive patients as compared with the volunteers and with the asymptomatic aged patients: peak filling rate was lower, time to peak filling rate was longer and the first-third filling fraction was smaller. After six weeks of nitrendipine therapy, systolic and diastolic blood pressure decreased significantly. After nitrendipine, the time to peak filling rate decreased and the first-third filling fraction and the peak filling rate (normalized for stroke counts) increased significantly. The acute oral administration of 100 mg atenolol induced a further decrease in systolic blood pressure and a significant decrease in heart rate. The effect of combining nitrendipine and atenolol on diastolic indexes was a preserved effect on time to peak filling rate and on the first-third filling fraction. These results suggest that short-term therapy with nitrendipine improves early diastolic dysfunction in hypertensives: the addition of a beta-blocking agent further improved the early diastolic indexes.

Adult↗
PubMed1986

Regional variations of iodine nutrition and thyroid function during the neonatal period in Europe.

In order to evaluate further the possibility that transient hypothyroidism and hyperthyrotropinemia in newborn infants could result from a state of relative iodine deficiency, the urinary concentration of iodine, used as an index of the dietary intake of iodine was determined in casual urine samples collected in 1,076 full-term infants aged 3-6 days in 16 cities in 10 different European countries and in Toronto, Canada. In addition, the results obtained by programs of systematic neonatal screening for congenital hypothyroidism in the same areas were compared. There were marked regional differences in iodine nutrition during the neonatal period in Europe (median urinary iodine: 16.2 micrograms/dl in Rotterdam, the Netherlands, and 1.1 micrograms/dl in Freiburg, FRG. A low iodine supply in newborn populations was accompanied by, and probably explained, an elevated frequency of transient disorders of thyroid function in young infants. Iodine prophylaxis is urgently needed in some European countries not only for the prevention of goiter, but mostly for the prevention of impairment of thyroid function during the critical period of brain development.

Canada↗
PubMed1986

Sex hormone-binding protein in hyperthyroxinemic patients: a discriminator for thyroid status in thyroid hormone resistance and familial dysalbuminemic hyperthyroxinemia.

Sex hormone-binding globulin (SHBG) levels in serum are affected by thyroid status; hyperthyroidism is associated with high SHBG levels, whereas hypothyroid patients have low or normal SHBG levels. This study was undertaken to test the usefulness of SHBG determinations to define the thyroid status in two hyperthyroxinemic states: thyroid hormone resistance (THR) and familial dysalbuminemic hyperthyroxinemia (FDH). Serum SHBG levels were determined in 193 patients and 26 normal subjects using an IRMA-type RIA. In the control group, the mean values in women (58.9 nmol/liter) and men (32.7 nmol/liter) were significantly different (P less than 0.001). In adult subjects with THR, SHBG levels were within the normal range, with mean values of 54.8 nmol/liter (range, 28.7-82.5 nmol/liter) in women and 18 and 20 nmol/liter in two men. In FDH subjects, the mean SHBG levels did not differ from the normal values; they averaged 60.7 nmol/liter in women and 42.3 nmol/liter in men. From these data we conclude that in THR and FDH, free T4 levels elicit an appropriate hepatic response corresponding to the euthyroid status of these subjects. SHBG determination may, therefore, serve as an in vitro test for end-organ sensitivity to thyroid hormones.

Drug Resistance↗
PubMed1986

Effects of iodide and thyroxine on iodine-deficient mouse thyroid: a morphological and functional study.

The effects of iodide and thyroxine (T4) on female mice fed a low iodine diet (LID) for 8 weeks were analysed by morphological, stereological and biochemical methods. Iodide was given at a dose of 10 micrograms/day (HID) or 1 microgram/day (MID), either alone or together with daily injections of 1 microgram T4 for 8 or 40 days. With HID, the thyroid weight and the numbers of follicles and cells remained higher than in controls, although cell necrosis occurred. Colloid volume increased and iodine was stored within the gland: a colloid goitre with non-functioning follicles was produced. With MID, the glands resumed an almost normal appearance. With T4 and LID, progressive normalization occurred, but after 40 days thyroid weight and numbers of follicles and cells remained higher than in controls. Glandular iodine content slowly increased and reached control value. The proportions of 125I-labelled tri-iodothyronine (T3) and T4 in thyroglobulin were reduced. With T4 and HID, the glands resumed a normal appearance. Neither necrosis nor folliculoneogenesis was noted. The proportions of 125I-labelled T3 and T4 in thyroglobulin were reduced, but T3 and T4 serum levels were higher than with HID. With T4 and MID, a normal state was obtained as early as day 8. After 40 days the gland was morphologically and functionally inactive. In conclusion, the association of T4 and iodide seems to be the best way to obtain a rapid and complete involution of thyroid hyperplasia. The administration of T4 prevents the deleterious effects of an excess of iodine on follicular cells, and causes the gland to enter a slow-functioning state.

Animals↗
PubMed1986

Diagnostic value of free triiodothyronine in serum.

Serum free T3 concentration has been assessed in various thyroid conditions by a T3 analog method and the results compared with those obtained by equilibrium dialysis in the same individuals. The methodology is easy to perform and reproducible. FT3 determination appears to be especially valuable in detecting borderline thyrotoxicosis as in cases previously cured from thyrotoxicosis but suspected of relapse, or in nontoxic goitrous patients overtreated with T4.

Evaluation Studies as Topic↗
PubMed1985

Effect of intracoronary thrombolytic therapy on exercise-induced ischemia after acute myocardial infarction.

Intracoronary streptokinase (SK) therapy increases vessel patency rate after acute myocardial infarction (AMI) and thus may lead to a greater exercise-induced myocardial ischemia. This hypothesis was tested in 39 patients enrolled in an angiographically randomized trial of intracoronary SK (19 treated with SK and 20 control subjects); all patients underwent thallium-201 scintigraphy at rest before acute angiography, as well as at rest and during stress 5 to 6 weeks after AMI. The patients were classified into 2 groups based on the presence (n = 13) or absence (n = 26) of complete obstruction of the infarct-related coronary artery at the end of the acute angiography. Semiquantitative score of myocardial thallium uptake was expressed as percent of maximal defect score. Thallium defect score at rest between admission and 5 to 6 weeks' study decreased from 10 +/- 16% units in the control group and from 23 +/- 14% units in the SK group (p = 0.01). This decrease was related to opening of the infarct-related artery (opening 23 +/- 16% vs occlusion 5 +/- 10%). The change in exercise-induced defect score was significantly (p = 0.01) larger in patients in the SK group (11 +/- 6% units) than in those in the control group (5 +/- 7% units). The perfusion defect during exercise was larger (p = 0.006) in patients with incomplete obstruction or reperfusion (10 +/- 6% units) than in patients with complete obstruction (3 +/- 7%). This difference was independent of the number of diseased coronary vessels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Coronary artery reperfusion in acute myocardial infarction: assessment by pre- and postintervention thallium-201 myocardial perfusion imaging.

In a randomized trial of intracoronary streptokinase (STK) therapy in acute myocardial infarction, 44 patients (21 control subjects and 23 patients treated with STK) underwent sequential thallium-201 planar imaging before angiography and after 4 hours (redistribution), 4 days and 6 weeks. Patients were classified according to the presence or absence of angiographic reperfusion of the infarct-related artery. The semiquantitative score of myocardial thallium uptake was expressed as percent of maximal defect score. Both in control and in STK-treated groups, thallium defect scores decreased over time, but this decrease was smaller in the control group (before angiography, 33 +/- 4%; redistribution, 29 +/- 4%; 4 days, 25 +/- 4%; and 6 weeks, 22 +/- 4%) than in the STK group (44 +/- 4%, 38 +/- 4%, 26 +/- 4% and 21 +/- 3%, respectively). In patients in whom reperfusion was achieved (20 STK-treated, 6 control subjects), a marked decrease in thallium score was observed (before angiography, 40 +/- 4%; redistribution, 32 +/- 4%; 4 days, 20 +/- 5%; and 6 weeks, 14 +/- 22%) compared with patients in whom reperfusion was not achieved (37 +/- 4%, 36 +/- 5%, 33 +/- 5% and 33 +/- 4%, respectively). These results indicate that serial thallium imaging is an accurate method of assessing changes in myocardial perfusion after acute myocardial infarction. Restoration of thallium uptake was observed after reperfusion of the infarct-related artery whether this recanalization was seen spontaneously or after successful thrombolysis.

Aged↗