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Biomedical subjects

N Amino

Publications and source records attributed to N Amino.

At least 253 records · Page 14Linked to original sources
PubMed1988

Morning sickness and thyroid function in normal pregnancy.

Thyroid function in early normal pregnancy was evaluated with reference to morning sickness using a newly developed free thyroxine (T4) radioimmunoassay and a highly sensitive TSH immunoradiometric assay. A significant increase in serum free T4 and a decrease in serum TSH were observed in early pregnancy relative to the levels in nonpregnant controls. The increased free T4 and hCG and decreased TSH correlated with the severity of morning sickness, and these changes were especially marked in subjects with nausea and vomiting. The individual serum levels of hCG in the pregnant group correlated significantly, directly with the levels of free T4 and inversely with those of TSH. The increased free T4 and decreased TSH in subjects with emesis returned to the normal ranges of nonpregnant controls after improvement of emesis. These data indicate that the thyroid gland is physiologically activated in early pregnancy, possibly by hCG or a related substance, which may induce gestational emesis. On the other hand, an increased level of free T4 and a reduced level of TSH in early normal pregnancy are not indications of thyrotoxicosis and may not necessitate antithyroid drug treatment.

Analysis of Variance↗
PubMed1987

A new radioimmunoassay of free thyroxine using 125I-labelled thyroxine-protein complex uninfluenced by albumin and thyroxine-binding globulin.

We describe a double-antibody solid phase radioimmunoassay for free thyroxine (FT4) in serum with use of 125I-labelled thyroxine-human chorionic gonadotropin conjugate. Since the labelled conjugate does not bind to thyroxine binding globulin (TBG) and albumin because of its large molecular weight, the method is uninfluenced by TBG or albumin. The measurable range of FT4 in serum was 2.0 to 128 ng/l. The mean coefficients of variation within and between assays were 4.6-8.6% and 6.3-11.6%, respectively. The FT4 values determined by the proposed method correlated well with those determined by commercial radioimmunoassay in subjects with normal albumin concentration (r = 0.98). The FT4 concentrations in serum as determined by this method were 9 to 17 ng/l for healthy adult subjects; high for patients with hyperthyroidism; low for patients with hypothyroidism; and within normal limits for pregnant women, and patients with high or low concentrations of thyroxine-binding globulin.

Albumins↗
PubMed1987

Separation and analysis of mononuclear cells infiltrating the thyroid of patients with Graves' disease.

A simple method was established for separating lymphocytes infiltrating the thyroid from thyroid epithelial cells. Namely, suspensions of minced thyroid from patients with Graves' disease were layered on a Percoll two-step density gradient (p = 1.050 and 1.077 g/ml) and centrifuged (400g, 30 min, 4 degrees C). In this way 0.1-18 X 10(5) lymphocytes/g of thyroid tissue with a purity of 65-95% were obtained. Thyroid lymphocytes were analyzed quantitatively with monoclonal antibodies by laser flow cytometry and compared with peripheral lymphocytes. The proportion of OKT3+ cells was decreased with increase in OKIa+ cells. The percentage of OKIa+ cells was significantly correlated with that of Leu12+ cells. The percentages of OKT4+ cells and OKIa+ cells were higher when analyzed with an extended gate window, which was arranged for detection of activated, large-sized lymphocytes. The percentages of OKT8+ and Leu7+ cells were not significantly different from those in peripheral blood. From these results it was concluded that the proportion of B lymphocytes is increased and that of T lymphocytes is decreased, the proportion of activated B lymphocytes is increased, some helper/inducer T cells are activated in the thyroid gland in Graves' disease, and these activated lymphocytes may be important in local production of antithyroid autoantibodies.

Adult↗
PubMed1987

In-vitro conversion of blocking type anti-TSH receptor antibody to the stimulating type by anti-human IgG antibodies.

We examined the relationship between blocking type anti-TSH receptor antibody (TRAb) and stimulating type TRAb by trying to convert blocking type TRAb to the stimulatory type in vitro. Immunoglobulins (IgGs) purified from sera of six patients with primary hypothyroidism blocked bovine TSH (100 microU/ml)-induced cAMP production (58.3-82.1% inhibition) in cultured porcine thyroid cells. None of these IgGs showed stimulating activity even after their dilution. In the conversion experiment, thyroid cells were first incubated with these IgGs at 34 degrees C for 30 min and then washed with incubation buffer. They were then incubated with various kinds of anti-human IgG antibodies first for 1.5 h at 4 degrees C and then for 18 h at 34 degrees C, and the cAMP concentrations in the supernatants were measured. All six IgGs showed strong, dose-dependent thyroid-stimulating activity after addition of antibodies against human whole IgG, or Fab or Fc fragments of IgG. The Fab or F(ab')2 fragments of goat anti-human IgG antibody also had these converting activities, although less than whole IgG. Addition of normal IgG in the first incubation or anti-human IgG antibody alone had no thyroid-stimulating activity. Anti-human IgA or IgM antibodies did not have these converting activities. These results show that blocking type anti-TSH receptor antibodies can be converted to the stimulating type by anti-human IgG antibodies in vitro. The results suggest that the blocking and stimulating types bind to the same epitope(s) of TSH-receptor related antigens. The same anti-TSH receptor antibody may act as a stimulator or blocker by the influence of other factors, such as anti-idiotype antibody.

Adult↗
PubMed1987

Serial changes in thyroid-stimulating antibody and thyrotropin binding inhibitor immunoglobulin at the time of postpartum occurrence of thyrotoxicosis in Graves' disease.

Thyroid-stimulating antibody (TSAb) and TSH binding inhibitor immunoglobulin (TBII) were measured serially in 10 patients with Graves' disease at the time of postpartum onset (n = 2) or relapse (n = 8) of Graves' thyrotoxicosis and in 5 patients with Graves' disease who were in remission and had no postpartum relapse of Graves' thyrotoxicosis. TSAb was measured by a sensitive cAMP accumulation assay using FRTL-5 cells, and TBII was determined by radioreceptor assay. In no patient with either recurrent or new onset postpartum hyperthyroidism did the serum free T3 index (FT3I) rise before the free T4 index (FT4I). Of the 10 patients who had postpartum thyrotoxicosis, concomitant increases in serum FT4I and FT3I, and TSAb and TBII were observed in only 1 patient. Increases in TSAb and TBII after those in FT4I and FT3I occurred in 6 patients. In 1 patient, an increase in TBII was associated with the occurrence of thyrotoxicosis, but TSAb increased 1 month later. In the other 2 patients, a TSAb increase was followed by the development of thyrotoxicosis, but TBII increased later. In 3 of these 10 patients, the increased serum FT4I and FT3I values decreased spontaneously, whereas the TSAb and TBII levels increased continuously. No positive test or increase in TSAb or TBII was found in the 5 patients with Graves' disease who did not have a postpartum relapse of thyrotoxicosis. These data indicate that postpartum initiation of Graves' thyrotoxicosis is not always associated with an increase in circulating anti-TSH receptor antibodies and that such parameters are poor indicators of thyroid function. Intrathyroidal humoral or cell-mediated immunological mechanisms may also be involved in mediating thyrotoxicosis in Graves' disease.

Autoantibodies↗
PubMed1987

Enzyme immunoassay of free triiodothyronine in serum.

In this new solid-phase antibody enzyme immunoassay for free triiodothyronine (FT3) in serum, beta-D-galactosidase conjugated to triiodothyronine is used. Results are uninfluenced by physiological concentrations of thyroxin-binding globulin or albumin. Results correlate well with those determined by equilibrium dialysis (r = 0.95). The mean CVs within and between assays were 6.1 and 9.5%, respectively. The measurable range of FT3 in serum is 0.7 to 26 ng/L; the normal reference interval is 1.9 to 8.9 ng/L. Concentrations of FT3 in serum of patients with hyperthyroidism were high; those of patients with hypothyroidism were within normal limits or low, and those of patients with congenitally decreased or increased TBG were within the normal range. In normal pregnant women, concentrations of FT3 as determined by radioimmunoassay correlated with those of albumin, declining as pregnancy progressed, but FT3 values determined by the proposed method or equilibrium dialysis were within the normal range and did not change during pregnancy.

Adult↗
PubMed1987

Decrease of free thyroxin in serum of lactating women.

We measured thyroid hormones and thyroxin-binding proteins in serum from 62 normal lactating and 52 nonlactating women at three months postpartum, and compared these values with those for 42 nonpregnant control women of similar age. Mean thyroxin concentrations in the lactating and nonlactating women were significantly (P less than 0.001) lower than that of the nonpregnant controls, but there was no significant difference (P greater than 0.2) in triiodothyronine concentration among these three groups. Free T4 concentration was significantly (P less than 0.01) lower in lactating women than in controls. The reverse-T3 concentrations in both lactating and nonlactating women were significantly (P less than 0.001) lower than in controls, and were significantly (P less than 0.001) lower in lactating than in nonlactating women. The concentration of thyroxin-binding globulin was significantly higher in lactating women than in controls, and the albumin concentration was significantly lower in women postpartum than in controls. Evidently, regulation of thyroid hormone in women postpartum, especially during lactation, differs from that in nonpregnant women.

Adult↗
PubMed1986

New indices for thyroid functional status, hormone binding, and peripheral hormone metabolism. Principal component analysis of 24,000 clinical data.

Principal component analysis of three thyroid function tests, thyroxine (T4), 3,5,3'-triiodothyronine (T3), and T3 uptake (T3U), was done using 24,000 data obtained from patients with a wide range of pathophysiologic conditions related to the thyroid. The three component scores were obtained as follows: Z1 = 2.62 square root T4 + 0.63 square root T3 + 3.18 square root T3U - 32.43; Z2 = 0.91 square root T4 + 0.24 square root T3 - 4.68 square root T3U + 20.14; and Z3 = 3.94 square root T4 + 0.95 square root T3 + 0.18 square root T3U - 1.53 (T4 micrograms/dL, T3 ng/dL, T3U%). The first component (Z1) represents an apparent axis to the direction of thyroid functional status. It provides a new metabolic index putting conventional free T4 and free T3 indices together. The second component (Z2) was found to be a sensitive indicator of abnormal hormone binding. It showed a close correlation with serum concentration of thyroxine-binding globulin. The third component (Z3) represents the degree of T3 predominance over T4. Computation of these scores will facilitate the diagnosis of atypical cases in which hyper-or hypothyroidism is complicated by abnormal peripheral hormone binding and/or metabolism.

Humans↗