Biomedical subjects

D Macejova

Publications and source records attributed to D Macejova.

5 recordsLinked to original sources

PubMed2005

Distinct modulation of a gene expression of the type 1 and 2 IP(3) receptors by retinoic acid in brain areas.

Inositol 1,4,5-trisphosphate (IP(3)) receptors belong to the intracellular calcium channels that release calcium from the intracellular stores after binding IP(3). Three types of IP(3) receptors occurred in a tissue specific manner and different promoters direct their gene expression. Thus, understanding of the transcriptional regulation is the first step towards comprehension of the function of these receptors. Since the retinoic acid activates RARE and AP2 transcription factors, the present study focuses on determination of whether or not expression of type 1 and 2 IP(3) receptors is modulated by retinoic acid in selected brain areas. We have found that mRNA levels of the type 1 IP(3) receptors were decreased significantly in cerebellum and hypothalamus, but not in the brain stem of rats treated with retinoic acid, compared to untreated littermates. The mRNA levels of the type 2 IP(3) receptor were significantly decreased in all tested tissues, cerebellum, hypothalamus, and also in brain stem after the treatment with retinoic acid. These results show that gene expression of both type 1 and 2 IP(3) receptors is regulated by retinoic acid, although the effect of retinoic acid on mRNA levels of the type 1 IP(3) receptors is dependent on brain area.

Animals↗

PubMed2004

Retinoic acid increased expression of the Na+/Ca2+ exchanger in the heart and brain.

The Na+/Ca2+ exchanger (NCX) is an important calcium transport system, which regulates intracellular calcium homeostasis. In particular, NCX is highly expressed in the plasma membrane of excitable neuronal and cardiac cells. We report here that binding of retinoic acid enhances expression of the NCX1 in the rat cardiac atria, brain stem and hypothalamus, but not in cerebellum. Differences in the regulation of the NCX1 by retinoic acid might suggest that GATA4-retinoic acid inducible transcription factor is activated in the hypothalamus and brain stem, but not in the cerebellum. Our results support the idea that inducible transcription factors play an important role in the fine-tuning of local tissue calcium homeostasis.

Animals↗

PubMed2003

Expression of nuclear retinoic acid receptor in peripheral blood mononuclear cells (PBMC) of healthy subjects.

In vertebrates, both nuclear all-trans and 9-cis retinoic acid receptors (RAR and RXR) belonging to the steroid/thyroid/retinoid nuclear receptor superfamily play a crucial role in the vitamin A action. Qualitative analysis of all known RAR or RXR subtypes in both pooled and non-pooled peripheral blood mononuclear cells (PBMC) from healthy human subjects has been performed by reverse transcription and polymerase chain reaction (RT-PCR). Our data, based on qualitative RT-PCR analysis has shown that human PBMC are capable to express RAR alpha, RAR gamma, RXR alpha, and RXR beta.

Cell Nucleus↗

PubMed2002

Transglutamines and endocrine system (minireview).

Transglutaminases catalyze the posttranslation modification of proteins by catalyzing Ca2+ dependent acyl-transfer reaction resulting in the formation of new g-amide bonds between g-carboxamide groups of peptide-bound glutamine residues and various primary amines. Such glutamine residue serves as acyl-donor and the most common acyl-acceptors are e-amino groups of peptide-bound lysine residues or primary amino groups of some naturally occurring polyamines, like putrescine or spermidine. The active site of cysteine reacts first with the g-carboxamide group of glutamine residue to form the acyl-enzyme intermediate under the release of ammonia. In the second step, the complex reacts with a primary amine to form an isopeptide bond and liberate the reactivated enzyme. The presence of transglutaminases has been observed in various endocrine glands such as human pituitary, which was investigated by immunohistochemical methods using specific antibodies. A significant increase in the expression and activity of tissue transglutaminase was observed during involution of thymus. In the genital tract of the male rat two different forms of the enzyme transglutaminase could be identified and characterized. the presence of p53 and tissues transglutaminase gene expressions in human normal and pathologic adrenal tissues. The Ca2+-responsive enzyme transglutaminase, which catalyzes the cross-bridging of proteins, was found in pancreatic islet cells.

Animals↗

PubMed2000

Histopathology of mammary tumours in female rats treated with 1-methyl-1-nitrosourea.

OBJECTIVE: To induce, evaluate and classify advanced stages of mammary gland tumours induced by MNU. METHODS: Female Sprague-Dawley rats were injected intraperitoneally with 1-methyl-1-nitrosourea (MNU; 50 mg.kg-1) on the day 33, 40, 47, 54 and 61 of age in the first experiment and on 50th and 113th day in the second experiment. On the 117th day (first experiment) and on the 153rd day of age (second experiment) the rats were sacrificed by decapitation and their mammary glands were evaluated both macroscopically and microscopically for the presence of grossly detectable mammary tumours. Mammary tumours were classified according to Russo et al. (1990). RESULTS AND CONCLUSIONS: The final incidence of palpable carcinomas was ranging from 60 % to 76 %. All microscopically evaluated tumours were malignant. Among the total number of lesions classified the percentage of invasive tumours ranged from 35 % to 44 %. No metastases were observed in other organs in MNU treated animals.

Adenocarcinoma↗