Biomedical subjects

Adam Gesing

Publications and source records attributed to Adam Gesing.

4 recordsLinked to original sources

PubMed2004

Increased thymidine kinase activity in human thyroid toxic adenomas: effects of exposure to epidermal growth factor in vitro.

UNLABELLED: The activity of thymidine kinase (TK-EC 2.7.1.21)--an enzyme functioning as a part of the pyrimidine salvage pathway of DNA synthesis--is closely related to growth processes. The aim of the study was to measure TK activity in homogenates of human thyroid tissue of the following types: non-toxic nodular goiter (NTNG)--macroscopically unchanged tissue, non-toxic adenoma (NTA), and toxic adenoma (TA) (obtained from patients, who--before the surgery--had been treated with thyrostatic drugs for thyrotoxicosis). Thyroid tissue was obtained from female patients subjected to subtotal thyroidectomy at the Department of Endocrine Surgery, Medical University of Lódź. Thyroid homogenates were incubated in the presence of epidermal growth factor (EGF), used in five different concentrations (0.1 ng/ml, 1 ng/ml, 10 ng/ml, 100 ng/ml, 1000 ng/ml). TK activity was estimated by chromatographic measurements of the amount of the main reaction product--deoxythymidine monophosphate. RESULTS: 1) We did not observe any significant difference between TK activity in the homogenates of the thyroid tissue collected from NTNG and NTA; TK activity was clearly higher in the homogenates of adenomatous tissue, collected from the patients with TA; 2) EGF increased TK activity in the homogenates of the macroscopically unchanged tissue, collected--during surgery--from the patients with NTNG, as well as in homogenates of thyroid tissue from NTA; 3) In case of hyperactive thyroid tissue, obtained from TA, EGF tended to increase TK activity, however, without any statistical differences. Our results confirm TK increased activity in hyperactive thyroid tissue. At the same time, the obtained data suggest a certain role of EGF in goiter formation in humans.

Adenoma, Oxyphilic↗

PubMed2003

Melatonin does not affect p21 expression in rat thyroid follicular cells.

OBJECTIVES: The cell-cycle (cc) is, in part, controlled by cyclin-dependent kinases (CDKs), which are activated after binding cyclins (positive regulators of cc). CDK inhibitors (CDKIs), such as p15, p16, p21, and p27, inhibit cyclin-CDK complex activity, and function as negative cell cycle regulators, blocking cell-cycle progression. The aim of our study was to examine the influence of late-afternoon (1600-1800) subcutaneous (s.c.) melatonin (Mel) injections, administered for 2 weeks, on the p21 expression in male Wistar rat thyroid follicular cells (TFC). METHODS: In order to detect the anti-p21 antibodies, the DAKO LSAB2 Rat Kit/HRP (DAKO, USA) and DAKO Liquid DAB Substrate-Chromogen System (DAKO, USA) were employed. RESULTS: No statistically significant changes of p21(LI) (p21 labelling index) values were observed in particular groups of the rats receiving Mel injections, in comparison to the controls. The statistical difference of p21(LI) values (p<0.03) was only observed between groups of rats, receiving Mel injections in the dose of 25 microg/daily and 100 microg/daily. CONCLUSION: Melatonin - in the applied doses and in the experimental conditions without any factors revealing anti-DNA activity - did not change, in any statistical way, p21 expression in rat thyroid follicular cells, as compared to the control group.

Animals↗

PubMed2000

Thymidine kinase and adenosine kinase activities in homogenates of thyroid lobes in hemithyroidectomized rats; effects of melatonin in vitro.

OBJECTIVES: Thymidine kinase (TK, EC 2.7.1.21) is a part of the pyrimidine salvage pathway, involved in DNA synthesis. In turn, adenosine kinase (AK, EC 2.7.1.20) functions as a part of the purine metabolic pathway, involved in DNA synthesis. Melatonin (Mel) is an indoleamine which is known to inhibit growth processes in the thyroid gland and also in other endocrine and non-endocrine tissues. The aim of our study was to examine TK and AK activities in homogenates of the rat thyroid lobes remaining after contralateral hemithyroidectomy (hemiTx); additionally, incubations with Mel (10(-6), 10(-9), and 10(-12) M) were performed. METHODS: The experiment was performed on young male Wistar rats (6-week old). The enzyme activities were measured by ascending chromatography and expressed as the amounts of radioactive reaction products of the phosphorylation of dThd (for TK) and of dAdo (for AK). RESULTS: 1. HemiTx increased TK activity in homogenates of the remaining thyroid lobe; 2. Mel increased TK activity in all the groups (intact, sham-operated- and hemiTx-rats), except for the concentrations of 10(-9) and 10(-12) M in the hemiTx-rats, in which the increasing effects of Mel on TK activity reached the borderline statistical significance only; 3. Mel increased the AK activity in intact and in shamTx animals; 4. No statistically significant changes were found in AK activity following Mel in vitro in the incubated remaining thyroid lobes, collected from hemiTx-rats.

Journal Article↗

PubMedDate not supplied

Effects of melatonin on the process of apoptosis in rat thyroid follicular cells.

OBJECTIVES: Apoptosis, or programmed cell death, is a normal component in the development of multicellular organisms and is essential for many physiological processes. Apoptosis is a process in which cells play an active role in their own death (apoptosis is often referred to as "cell suicide"). Disturbances of apoptosis regulation can result in many diseases. Certain substances (for example--aflatoxin B1; AFB1) can induce apoptosis in various organs and tissues. Melatonin (Mel) is a hormone (indoleamine) which has antioxidant, antiproliferative and, potentially, anticancerogenic activities. The aim of our study was to examine the influence of late-afternoon (1600-1800) intraperitoneal (i.p.) Mel injections, administered for 3 weeks, on the process of apoptosis in male Wistar rat thyroid follicular cells (TFC); Mel was injected alone or together with AFB1 (i.p., also once daily for 3 weeks). METHODS: In order to assess the process of apoptosis, evaluated in microscopic preparations of rat thyroids, an In Situ Cell Death Detection, POD Kit [Roche, GER] and the DAKO Liquid DAB Substrate-Chromogen System [DakoCytomation, USA] were employed. RESULTS: Aflatoxin B1 increased the apoptotic index (I(apopt)) in rat TFC, in comparison to controls (p<0.001). The I(apopt) value in the rats, receiving Mel and AFB1 injections, was statistically lower, as compared to the value of the examined index in the group of AFB1-treated animals (p<0.001). No statistically significant differences of I(apopt) value were observed between the Mel-treated group of animals and the controls. CONCLUSION: Melatonin can assumingly regulate the growth of cells and tissues by influencing the process of apoptosis.

Aflatoxin B1↗