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Biomedical subjects

P Keating

Publications and source records attributed to P Keating.

8 recordsLinked to original sources
PubMed1992

Thyroid growth immunoglobulins in feline hyperthyroidism.

Feline hyperthyroidism bears a strong clinical and pathologic resemblance to toxic nodular goiter in humans. To evaluate whether the observed thyroid growth might be due to circulating thyroid antibodies, as has been postulated in humans, we studied the effect of purified immunoglobulin (Ig) G preparations on a rat thyroid follicular (FRTL-5) cell line. When compared with control, hyperthyroid cat IgG caused significantly increased [3H]-thymidine (Tdr) incorporation into DNA (p less than 0.02) and stimulated cellular proliferation 15-fold. Stimulation of 3H-Tdr incorporation tended to be biphasic and could be inhibited completely by a potent, specific TSH receptor blocking antibody. Hyperthyroid cat IgG also significantly inhibited 125I-bTSH binding to porcine thyroid membranes, an effect that could be reproduced using electrophoretically pure IgG and normal cat thyroid membranes. Unlike its effect on growth, hyperthyroid cat IgG did not stimulate intracellular cAMP, and there was no correlation between thyroid function in vivo and IgG growth-promoting activity in vitro. These data suggest that elevated titers of thyroid growth IgGs, probably acting through the TSH receptor, are present in feline hyperthyroidism and may play a role in goiter formation. Unlike growth, the thyroid hyperfunction observed is not IgG dependent. Further study of feline hyperthyroidism may contribute important insights into human nodular goiter and into the mediation of thyroid growth in general.

Adenylyl Cyclases↗
PubMed1991

Use and detection of nonradioactive iodine-labeled antibodies for immunoassay.

Traditionally radioactively labeled iodine has been used as a reporter group for the detection of antibodies in immunoassay. We have recently developed a microassay system for the detection of very low concentrations of iodide which eliminates the need for the use of radiolabeled iodine (O'Kennedy, R. et al. 1989, Anal. Biochem. 179, 138-144). The successful application of this assay for the detection of mouse IgG is described. The performance of this system compared with enzyme immunoassay was evaluated.

Animals↗
PubMed1990

Maternal thyroid-blocking immunoglobulins in congenital hypothyroidism.

We evaluated 24 mothers whose babies had congenital hypothyroidism (CH) for the presence of immunoglobulins (Igs) that inhibited [125I]bovine TSH binding and blocked TSH-induced growth and function of FRTL-5 cells. Results were compared with those from 2 mothers with known primary myxedema (atrophic thyroiditis) whose babies had transient CH and with normal controls. Only 1 prospectively evaluated CH mother had potent TSH binding inhibitory, growth inhibitory, and function inhibitory IgGs. Further study of this discordant mother's serum indicated that she was hypothyroid, probably due to atrophic thyroiditis. Both mothers with known primary myxedema had blocking IgGs. The thyroid growth-blocking activity was verified by cell count, could be absorbed by and eluted from Staphylococcal protein-A, indicating that it was an IgG, and was not an anti-TSH idiotype. Half-maximal inhibition was similar in the three different assays for thyroid-blocking activity, suggesting that TSH binding inhibitory, growth inhibitory, and function inhibitory IgGs in some patients with primary myxedema may be the same antibody population. There was no correlation with the titer of antimicrosomal antibodies. These data suggest that maternal thyroid-blocking IgGs interacting with the TSH receptor do not play a role in most cases of sporadic CH. Determination of TSH binding inhibitory IgGs, but not antimicrosomal antibodies, is a sensitive screening test for the presence of TSH receptor-blocking antibodies.

Adult↗
PubMed1990

Constipation.

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Adolescent↗
PubMed1978

Fundamental frequency in the speech of infants and children.

Fundamental frequency ranges of six normal infants and children from 33 to 169 weeks were determined by narrow-band spectrographic analysis. Fundamental frequency values ranged from 30 to 2500 Hz, well outside the values reported in previous studies of noncry utterances. The use of fry, modal, and high registers is also discussed.

Acoustics↗
PubMed1978

Effects of transition length on the perception of stop consonants.

This study investigated the effects of lengthened transitions on the perception of stop consonants. In experiment I, three continua representing the phonetic categories [da] and [ga]containing transitions of 45, 95, or 145 ms were presented to 20 subjects for both labeling and discrimination. Results indicated that although there was a significant change in identification performance from 95 to 145 ms, the shape of the functions, and the locus and slope of the phonetic boundary did not significantly vary across transition lengths. In addition, discrimination of within-category stimulus comparisons was significantly better at the 95-ms transition length than at 45 or 145 ms. In experiment II, the availability of acoustic information was investigated further with the adaptation paradigm. Eight subjects labeled the 45-ms series before and after adaptation with 45-, 95-, and 145-ms [da] stimuli. No effect of transition length was found. These results suggest that the slope and duration of formant transitions seem to contribute minimally to the perception of place of articulation in stop consonants.

Discrimination, Psychological↗