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Biomedical subjects

M Polak

Publications and source records attributed to M Polak.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Hyperfunctioning thyroid adenoma and activating mutations in the TSH receptor gene.

Thyrotropin (TSH) positively controls the function, differentiation, and growth of thyrocytes. TSH interacts with thyrocytes through the TSH receptor and its action is mediated by cyclic AMP-dependent mechanisms. From data gathered on adrenergic receptors, it was hypothesized that TSH receptor mutations that lead to constitutive activation of the TSH receptor would also result in autonomous thyroid growth and function. Indeed, such mutations were shown to be the main molecular mechanisms leading to toxic thyroid adenomas. The same mechanism was shown to be operating in "hot" thyroid nodules from multinodular goiter. A low iodine supply seems to increase the clinical expression of such somatic mutations responsible for thyroid autonomy. Moreover, the presence of such mutations has helped to define a working model for TSH receptor physiology. The unliganded TSH receptor maintains a negative constraint on the signal transduced, whereas the presence of specific mutations activates the receptor.

Adenoma↗
PubMedDate not supplied

Assessment of fetal thyroid function by colored Doppler echography.

BACKGROUND: The association of hyperthyroidism and pregnancy is a rare but serious condition which can jeopardize fetal outcome. Classical follow-up relies on: serial clinical and echographic assessment; serial funipuncture to determine fetal thyroid status, and maternal propylthiouracil (PTU) treatment to treat fetal and/or maternal hyperthyroidism. CASE: We report the case of a euthyroid patient with Graves' disease who had already been delivered of two hyperthyroid fetuses; the present pregnancy revealed a hyperthyroid fetus diagnosed by funipuncture. Echography showed a fetal goiter at 28 weeks of gestation (WG) with important signal on colored Doppler echography. We observed an extinction of this signal as maternal PTU treatment was intensified. The patient was delivered of a mildly hyperthyroid newborn at 37 WG. Both newborn and patient are doing well. CONCLUSION: Fetal thyroid assessment by colored Doppler echography could help in the management of fetal thyroid dysfunction.

Adult↗
PubMedDate not supplied

Effect of thiol drugs on the oxidative hemolysis in human erythrocytes.

The effect of different thiol drugs and 2-methyl-thiazolidine-2,4-dicarboxylic acid on the oxidative stress, induced by hydrogen peroxide, was examined in human erythrocytes. The results indicated that captopril (CA), methimazole, N-acetylcysteine (NAC), penicillamine and precursor of L-cysteine 2-methyl-thiazolidine-2,4-dicarboxylic acid (CP) might protect the erythrocyte membrane against lipid peroxidation in the experimental conditions. Captopril, methimazole and penicillamine had the strongest antioxidative properties at the concentration level of 0.5 mM. The protective effects gradually decreased at higher and lower concentrations of these drugs. Contrary, the antioxidative properties of N-acetylcysteine increased with its levels growing in the reaction mixture, and only N-acetylpenicillamine did not protect erythrocytes against oxidative damages. The effect of 2-methyl-thiazolidine-2,4-dicarboxylic acid showed in these in vitro experimental conditions that it could act as an antioxidant at the concentration as high as 5 mM and higher.

Acetylcysteine↗
PubMedDate not supplied

[State of periodontium in patients using partial removable dentures].

The authors have examined 63 patients whom 86 partial removable dentures: functionally unstable dentures and supported ones in all have been made. The state of paradontium basing on G-I gingival index and Pl-I plaque index has been estimated. It has been found that the state of paradontium in the group of supported dentures irrespective of the utilization life was better than in the group of functionally unstable dentures.

Denture, Partial, Removable↗
PubMedDate not supplied

[Electronystagmographic evaluation of the vestibulo-ocular reflex in children after brain concussion].

The purpose of the study was a trial of using the calorie pendulum test and the test of reversal of the direction of caloric nystagmus with an optokinetic stimulus for assessment of the oculovestibular response in children after brain commotion. The investigations were carried out in 30 children aged from 6 to 10 years. In both tests the movements of the eyeballs were recorded with an electronystagmograph. It was found that in this type of craniocerebral trauma a transient disturbance occurs in the functions integrating the visual and vestibular stimuli in the central nervous system. It is suggested that these tests might be useful for determination of the otoneurological status of children after brain commotion.

Brain Concussion↗