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Biomedical subjects

F J Seif

Publications and source records attributed to F J Seif.

At least 37 records · Page 2Linked to original sources

[Thyrotropin-displacing antibodies in thyroid gland diseases].

Thyroid-stimulating antibodies were assayed in 798 patients with thyroid diseases and 122 controls by means of a heterologous radioreceptor assay as thyrotropin displacement activity (TDA). With an intraassay variance of 5-6% and an interassay variance of 8-13% in higher TDA values, test results were well reproducible. Thus, TDA assay is suitable for routine testing and follow-up of titers in the upper range. With only few exceptions TDA values of F greater than or equal to 11% are found exclusively in Graves' disease (sensitivity 39.2%; specificity vs other thyroid diseases 99.7%). In patients with functional autonomy in nodular goitre (Plummer's disease) TDA is consistently negative. TDA measurement is a valuable means for the detection of Graves' disease and for differential diagnosis of hyperthyroidism of undetermined pathogenesis.

Antibodies↗

[Partial lipodystrophy syndrome (Dunnigan type)].

Special forms of partial lipodystrophy, which in contrast to the progressive lipodystrophy of Barraquer-Simons spare the face, have been reported by Dunnigan and Köbberling. Lipodystrophy of the Dunnigan type affects the trunk and limbs; in lipodystrophy of the Köbberling type the loss of subcutaneous fat is restricted to the extremities. The following case report deals with the main clinical and laboratory findings in lipodystrophy of the Dunnigan type.

Acanthosis Nigricans↗

Myasthenia gravis: overlap with 'polyendocrine' autoimmunity.

81 patients with spontaneously acquired myasthenia gravis (MG) were investigated for the presence of autoimmune (AI) diseases and their sera were tested for a range of organ-specific autoantibodies. 77 of the patients were HLA-phenotyped. Antibody titres to acetylcholine receptors (AChR) were higher in non-thymomatous patients who possessed HLA-B8 (p less than 0.05) and/or -DR3 (p less than 0.05) as compared to patients lacking these HLA antigens. 3 out of 20 (15%) patients with ocular MG, 7/23 (30%) with generalized MG of early onset, 11/23 (48%) generalized MG of late onset and 5/14 (35%) patients with thymoma had either overt AI diseases or significant titres of organ-specific autoantibodies suggesting subclinical AI disease. In ocular MG, low titres and an infrequent finding of antibodies to AChR (32%) as well as the low prevalence of associated autoantibodies and AI diseases indicate that this subgroup of MG consists of patients with restricted AI reactivity. HLA-B8 and -DR3 were present in all the patients with associated AI disorders in the young onset group but in none of the patients with old age of onset. In the young group, 6 out of 7 patients with associated AI conditions were women whereas the sex ratio was about equal in the older cases in both, patients with and without associated AI diseases or autoantibodies. We conclude from these observations that ageing provides conditions that allow the breakdown of self tolerance. The simultaneous presence of HLA B8, DR3 and female sex provide important additional factors for early expression of MG.

Adult↗

[Changes in thyroid function following iodine-containing contrast administration in patients in an endemic goitre area (author's transl)].

A prospective study of thyroid function after the administration of iodine-containing radiographic contrast media was carried out on 119 patients from an area where goitres are endemic. Eighteen patients had a negative TRH test after 28 days. 27.9% of patients after oral cholecystography, 15.1% of patients after intravenous cholangiography and 5.3% of patients after infusion urography, showed hyperthyroid function. In these patients, thyroxin and triiodothyronine levels were higher than in euthyroid patients. Thyroid stimulating antibodies could not be demonstrated. Induction of hyperthyroidism by iodine is considered to be due to autonomy of the thyroid gland parenchyma. For this reason the risk of iodine-induced hyperthyroidism is greater in patients from a goitre endemic region (by a factor of 1.3 to 17.1).

Contrast Media↗

Micromethod of human thyrocyte cultures for detection of thyroid-stimulating antibodies and thyrotrophin.

The activation of adenylate cyclase of human thyrocytes in primary cell cultures and the release of cAMP into the medium are used to detect thyrotropin (TSH) and thyroid-stimulating antibodies (TSAb) in sera of patients with Graves' disease. Tissue digestion and cell dispersion are performed using a neutral protease of Bacillus polymyxa (Dipase II), which harvests more vital thyrocytes than does trypsin. The cells show an enhanced response to stimulation. The efficiency of the cell preparation and cultivation is increased by using microtest plates instead of culture flasks. By this minimization only 0.6-1.8 X 10(6) cells are needed to evaluate a single sample. Cyclic AMP concentrations are measured directly in the supernatant culture medium by a competitive protein binding assay with charcoal separation. The minimal detectable dose of bTSH is about 10 microU/ml. With increasing doses of bTSH cAMP concentrations rise to a peak at about 50 to 100 mU/ml, beyond which there is a gradual decrease of cAMP indicating negative cooperativity in the activating mechanisms. The 'long-acting thyroid stimulator' effect of TSAb is reflected by a protracted increase of cAMP to its maximal value. All 41 sera of hyperthyroid patients with Graves' disease were TSAb-positive, whereas sera of patients with toxic nodular goitre and euthyroid controls were TSAb-negative.

Autoantibodies↗

[Iodine-induced hyperthyroidism due to contrast media (author's transl)].

A prospective study in an area with endemic goitre showed 18 patients (15.1%) out of 119 investigated with iodine containing contrast media to be hyperthyroid after 28 days. Oral cholecystography led to the highest (27.9%) and infusion urography to the lowest (5.3%) rate of hyperthyroidism. Determination of the serum concentration of thyroxine, triiodothyronine, basal and stimulated thyrotropine is not a suitable method to detect the risk for hormonally euthyroid patients before a contrast media investigation.

Cholecystography↗

[Ectopic production of chorionic gonadotropin in apudomas (author's transl)].

Two pheochromocytomas, two carcinoid tumours of the ileum and one pancreatic vipoma showed APUD-system properties and formed electron-dense secretory granules indicating synthesis and storage of proteohormones. Besides catecholamines, 5-hydroxytryptamine and vasoactive intestinal polypeptide, all five tumours contained immunoreactive chorionic gonadotropin and also its free, protomeric beta chain as a sign of de-differentiation. Plasma of the tumour patients also contained immunoreactive chorionic gonadotropin and the free protomeric beta chain, both of which are useful tumour markers.

Acute Kidney Injury↗

Mathematical model of pituitary thyrotropic function.

A nonlinear differential equation is used to develop a mathematical model describing the time course of thyrotropin (TSH) concentral to real data shows that pituitary responsiveness to TRH is highest in euthyroidism, reduced in primary hypothyroidism, and lowest in hyperthyroidism.

Feedback↗

[The vaso-active intestinal polypeptide in Verner-Morrison syndrome].

A 40-year-old man with the Verner-Morrison syndrome (refractory watery diarrhoea and hypokalaemia in islet-cell tumour of the pancreas) had an islet-cell carcinoma of the non-B-cell type with metastases to liver and mesenteric lymph nodes. High concentrations of a vasoactive intestinal polypeptide (VIP) were demonstrated in tumour tissue and plasma by radioimmunological tests. After surgical removal of the tumour the plasma VIP concentration fell to normal. Immunohistochemical tests of the tumour for gastrointestinal hormones demonstrated marked fluorescence only for vaso-active intestinal polypeptide. It is assumed that this polypeptide is largely responsible for the clinical signs. In the described case the severe watery diarrhoea ceased after glucocorticoid administration.

Acute Kidney Injury↗