Nuclear localization and characterization of alkaline phosphatase in neutrophils from normal controls and pregnant women.

There were controversial data concerning localization of alkaline phosphatase (AP) in neutrophil nuclei under physiological conditions. In this context, the AP pattern has been determined on nuclei preparations from normal human neutrophils. Blood cells were isolated from 10 healthy adults and from 3 women in the third trimester of an uncomplicated pregnancy. Purity of nuclear suspension was checked by electron microscopy and assay of organelle marker enzymes. Electron microscope cytochemistry and immunocytochemistry studies were carried out on WBC. Enzyme characterization was performed by the usual biochemical procedures. AP was found in nuclear preparations from four of ten normal controls. When present, AP was detected in approximately two-thirds of the nuclei examined, representing an average of 20% of the total cell activity. Conversely, a large amount of nucleus-bound enzyme (55% of total AP activity) was recognized in all pregnant women samples. Biochemical and immunological characteristics clearly differentiate AP forms in the two groups of subjects. Normal controls have an heterogeneous enzyme pattern. AP positive preparations contain a mixture of isoenzymes: a prominent heat labile form and a relatively heat stable minor component. The heat stable fraction displays some properties similar to those previously described in leukocyte AP. Pregnant women express a unique very heat labile isoenzyme identical in its main characteristics to the early placental type.

Thyroid function tests in ageing and their relation to associated nonthyroidal disease.

Thyroid function tests of 179 euthyroid geriatric inpatients (83 +/- 6 yr) unaffected by acute diseases or malnutrition were investigated and compared with those of 76 ambulatory healthy younger subjects (42 +/- 13 yr). Elderly population was divided in three groups, respectively: group G I (n = 37, 65-78 yr), group G II (n = 64, 79-85 yr) and group G III (n = 78, over 85 yr). Severity-of-illness index of the patients was evaluated at entry in the study protocol. While total thyroxine (TT4), free triiodothyronine (FT3) and TSH levels remained unchanged, circulating total triiodothyronine (TT3) was significantly lower (113 +/- 32 vs 150 +/- 31 ng/dl, p less than 0.05) and free thyroxine (FT4) was significantly higher (12.4 +/- 2.7 vs 10.3 +/- 2.3 pg/ml, p less than 0.05) in aged people. Furthermore, TT3 decreased significantly from 130 +/- 36 in G I to 110 +/- 33 in G II and to 108 +/- 25 in G III (p less than 0.01), and FT4 increased progressively although not significantly in the same groups. A close correlation was found between TT3 and severity index in male observations only (r = -0.43, p less than 0.01), as well as between FT4 and severity index in both sexes (r = 0.51, p less than 0.001 for men, r = 0.21, p less than 0.01 for women). These data suggest that thyroid function tests have to be cautiously interpreted in a geriatric population, particularly in relation to the severity of the clinical state, and reference values should be determined for TT3 and FT4 in the ageing process.

[Specific receptors for triiodothyronine in nuclei isolated from normal human polynuclear neutrophils]. / Récepteurs spécifiques à la triiodothyronine dans les noyaux isolés de polynucléaires humains normaux.

In normal subjects, nuclei isolated and purified from circulating granulocytes bound 125I-T3. Binding was reversible and inhibited by unlabelled hormone. Scatchard plots showed a single class of high affinity sites (Kd: approximately 1,5 nM) with a high maximal binding capacity (MBC: approximately 400 fmol of T3 bound/100 micrograms of DNA). Structural analogs partially competed with 125I-T3 binding. These data suggest that human normal polymorphonuclear neutrophils possess specific nuclear receptors for triiodothyronine.

[High blood triiodothyronine and the euthyroid state]. / Hypertriiodothyroninémie et euthyroide.

A high excess of circulating T3 was observed in an euthyroid woman. Agarose gel electrophoresis of serum preincubated with 125I-T3 revealed an abnormal T3-binding in gamma-globulin zone. This binding interfered with the hormone radioimmunoassay. Immunological characterization identified this protein as an IgG-K and IgG-lambda polyclonal antibody that bound T3 but not T4. Scatchard analysis of 125I-T3 binding to the gamma-globulin fraction isolated showed a single class of binding sites with a high affinity Ka = 0.4 X 10(9) L/M and maximal binding capacity of 5.2 X 10(-9) M.

[Insulin binding to isolated thyroid plasma membrane]. / Liaison de l'insuline aux membranes plasmiques isolées thyroïdiennes.

Binding sites of insulin were detected in plasmic membranes isolated from bovine thyroid. Membrane 123I-insulin binding was inhibited by unlabelled insulin, at a lower degree by proinsulin, not at all by TSH and GH. Binding dissociation appeared to be consistent with the process of cooperative negativity. These data suggest that specific receptors binding to insulin are present in thyroid isolated plasmic membranes.

[Specificity and reversibility of insulin binding to isolated thyroid nuclei]. / Spécificité et réversibilité de la liaison de l'insuline aux noyaux isolés thyroïdiens.

Inhibition studies of nuclear binding of labelled insulin by unlabelled insulin, proinsulin and polypeptide hormones (glucagon, GH, TSH) as well as kinetics of binding dissociation suggest that thyroid isolated nuclei specifically, at least pro parte, and reversibly bind to insulin.