GLIKOZILACIJA PROTEINA POSTELJICE U ANEMBRIONALNOJ TRUDNOĆI

Blighted ovum is a form of miscarriage, involving the absence or disappearance of an embryo very early in pregnancy. Due to contemporary lack of understanding of the nature of blighted ovum, our objective was to demonstrate the glycosylation patterns of placental proteins in this failure of pregnancy. Six placentas were taken from women with blighted ovum and twentyone placentas were provided from healthy women undergoing elective termination of normal pregnancies. Olygosaccharide branches were detected by Western-blot method using lectins: SNA and PHA-E, after preliminary separation of proteins by discontinuous SDS-PAG electrophoresis. Much stronger expression of GP74 has been identified in blighted ovum at the beginning of the eleventh week of gestation (with PHA-E), than in normal placenta. The same result was obtained for GP25 being stronger in blighted ovum at the end of eleventh week (with SNA). It is possible to conclude that the differences in glycoprotein changes beetwen the blighted ovum and the normal placenta, can only be found at the quantitative level, but not at the qualitative level.»Blighted ovum« (anembrionalna trudnoća) predstavlja oblik pobačaja, koji uključuje nedostatak ili nestanak zametka vrlo rano tijekom trudnoće. Dosadašnja skromna saznanja o ovom poremećaju potaknula su nas na detaljnija ispitivanja prikaza glikozilacijskih obrazaca placentarnih proteina. Promjene glikoproteinskog sastava detektirane su Western-blot metodom koristeći lektine SNA i PHA-E, koja je slijedila nakon preliminarne separacije proteina diskontinuiranom PAGE elektroforezom. Uspjeli smo identificirati mnogo jaču ekspresiju GP 74 u blighted ovum-u, nego u normalnoj placenti na početku jedanaestoga tjedna trudnoće, koristeći lektin PHA-E. Isti smo rezultat dobili i za GP25, koji je bio jačeg intenziteta u blighted ovum-u pri kraju jedanaestoga tjedna, koristeći lektin SNA. Naši rezultati navode nas na zaključak da se razlika između blighted ovum-a i normalne placente može uočiti samo na razini kvantitativnih glikoproteinskih promjena, ali ne i na kvalitativnoj razini

THE ROLE OF GLYCOPROTEINS IN THE PROCESSES OF IMPLANTATION AND PLACENTATION

Implantacija se danas smatra centralnim događajem u razvoju zametka sisavaca, a zahtijeva usklađen odnos između dvije vrste tkiva koja dolaze u interakciju: trofoblasta i sluznice maternice. Za razumijevanje molekularnih mehanizama implantacije od ključnog je značenja poznavanje zbivanja na razini međustaničnog prepoznavanja i međuodnosa stanica i međustaničnog matriksa. Glikoproteini se općenito smatraju potencijalnim medijatorima staničnih interakcija u brojnim biološkim sustavima, uključujući procese prepoznavanja i adhezije. Ovaj rad donosi sustavni ¬pregled glikoproteinskih molekula koje sudjeluju u procesima implantacije i placentacije te njihovu ulogu u navedenim događajima.The proces of implantation is considered nowadays to be the central event in the development mammalian embryo. Implantation requires very subtle interactions between two tissue types: the trophoblast of the embryo and the endometrium of the uterus. In order to better understand the molecular mechanisms of implantation, it is crucial to investigate events of intercellular recognition and interaction beetwen cells and extracellular matrix. Glycoproteins are considered to be the potential mediators of cellular interactions in a number of biological sistems, including processes of cellular recognition and adhesion. This paper reports on an extended review of glycoprotein molecules that are responsible for biological processes of implantation and placentation, and studies their roles in these events

Comparison of Glycosylation Patterns of Placental Proteins Between Normal Pregnancy and Missed Abortion

Contemporary understanding of missed abortion, as the case of spontaneous abortion where embryo is retained in uterus for four weeks or more after its death, is very poor. Aiming to improve the level of knowledge about this process, we have compared glycosylation patterns of placental proteins in normal pregnancy and missed abortion. Oligosaccharide branches were detected by Western-blot using SNA, DBA and PHA-E lectins. The comparison of samples of the same gestational age enabled identification of changes in protein glycosylation between normal and pathological placentas. Lectin DBA detects in normal placenta the glycoprotein GP 105 during the eleventh week, which is absent in missed abortion. PHA-E identifies GP 71 during fourteenth week only in normal placenta. However GP 25 recognized by SNA in missed abortion was not found in normal pregnancy at tenth week. These results indicate that abnormal placental development is associated with changes in glycoprotein structures, and that glycoconjugates might have an important role in placental development

Preživljenje fetusa određeno utjecajem 5-azacitidina na placentu

DNA methylation as a regulatory mechanism for mammalian gene expression is involved in the process of placentation as well as foetal development. 5azaC is a demethylating agent, which incorporates into DNA instead of cytosine and prevents its methylation, subsequently changes expression of genes involved in normal placental and foetal development. Single dose of 5azaC (5 mg/kg) was administered to pregnant rats at 11th, 12th and 13th day of gestation. Placentas and foetuses were isolated at day 20, weighted and histologicaly analyzed. After 5azaC administration on the 11th day of gestation, treated placentas were significantly smaller and labyrinth was significantly reduced. Consequently complete foetal resorption occurred. When administrated at day 12 of gestation, labyrinth was slightly recovered and 24% foetuses survived, while after its application at 13th day of gestation, almost normal distribution of placental layers was found and survival was 96%. These results confirmed epigenetic influence upon placental development. 5azaC caused changes in its structure, especially the reduction of labyrinth that is crucial for foetal survival. After establishment of normal placental layers distribution, 5azaC has no impact on placental morphology, neither on foetal survival. On the other hand, the influence of 5azaC remains visible in appearance of foetal malformations.Metilacija DNA kao regulatorni mehanizam ekspresije gena u sisavaca uključena je kako u procese placentacije tako i razvitka fetusa. Demetilacijsko sredstvo 5azaC ugrađuje se u DNA umjesto citozina i sprječava njegovu metilaciju, što ima za posljedicu promijenjenu ekspresiju gena uključenih u normalnu placentaciju i fetalni razvitak. Trudne ženke Fisher soja štakora tretirane su s 5 mg/kg 5azaC jedanaestog, dvanaestog i trinaestog dana gestacije. Dvadesetog dana gestacije izolirani su, izvagani i histološki analizirani kako fetusi tako i placente. Nakon primjene 5azaC jedanaestog dana gestacije, tretirane placente bile su značajno manje, a labirint reduciran, zbog čega je uslijedila potpuna resorpcija fetusa. Dvanaesti dan primjene 5azaC rezultirao je blagim povećanjem labirinta, a preživljenje fetusa bilo je 24%. Tek trinaestog dana aplikacije 5azaC uspostavila se normalna distribucija labirinta i bazalnog sloja s preživljenjem od 96%. Dobiveni rezultati potvrđuju epigenetski utjecaj na razvitak placente. Primjena 5azaC uzrokovala je promjene u strukturi placente, osobito redukciju labirinta čija je uloga očito ključna za preživljenje fetusa. Nakon uspostave normalne građe placente, 5azaC više nije imao utjecaja na njezinu morfologiju niti na preživljenje fetusa. S druge strane, njegov je teratogeni utjecaj ostao i dalje vidljiv na fetusima u obliku različitih malformacija

Praćenje onkoloških bolesnika – kliničke preporuke Hrvatskog društva za internističku onkologiju HLZ-a 1. Dio: rak dojke, rak tijela maternice, rak vrata maternice, rak jajnika [Cancer patients follow-up – Croatian society of medical oncology clinical guidelines Part I: breast cancer, uterine cancer, cervical cancer, ovarian cancer]

Treatment of oncological patients must be based upon multidisciplinary approach, and takes place in specialized oncological centers. By the end of a specifi c oncological treatment further follow-up is managed mostly by the oncologists, but the role of the general practitioners becomes more important every day and therefore should be precisely defi ned. Nowadays, most of the existing follow-up guidelines are not based on prospective studies, but on the experts opinion of a particular oncological center or specialists. The aim of the Croatian Society of Medical Oncology (CSMO) with these recommendations is to standardise and rationalise the diagnostic procedures algorithm in the follow-up of oncological patients after primary treatment

CANCER PATIENTS FOLLOW-UP – CROATIAN SOCIETY OF MEDICAL ONCOLOGY CLINICAL GUIDELINES Part I: breast cancer, uterine cancer, cervical cancer, ovarian cancer

Liječenje onkoloških bolesnika mora se temeljiti na multidisciplinarnom pristupu, a provodi se u specijaliziranim onkološkim centrima. Nakon završetka specifičnog onkološkog liječenja daljnje praćenje uglavnom provode onkolozi, ali je uloga liječnika primarne zdravstvene zaštite (PZZ) sve važnija i potrebno ju je jasno definirati. Trenutačno se većina preporuka za praćenje ne temelji na prospektivnim studijama, već se zasniva na stručnim mišljenjima pojedinih onkoloških centara ili specijalista. Hrvatsko društvo za internističku onkologiju (HDIO) ovim preporukama želi standardizirati i racionalizirati dijagnostičke postupke u praćenju onkoloških bolesnika nakon završetka primarnog liječenja.Treatment of oncological patients must be based upon multidisciplinary approach, and takes place in specialized oncological centers. By the end of a specific oncological treatment further follow-up is managed mostly by the ­oncologists, but the role of the general practitioners becomes more important every day and therefore should be precisely defined. Nowadays, most of the existing follow-up guidelines are not based on prospective studies, but on the experts ­opinion of a particular oncological center or specialists. The aim of the Croatian Society of Medical Oncology (CSMO) with these recommendations is to standardise and rationalise the diagnostic procedures algorithm in the follow-up of oncological patients after primary treatment

DNA methylation as a regulatory mechanism for gene expression in mammals

Epigenetics refers to the study of heritable changes in gene expression that occur without a change in DNA sequence. In the last decade, it has been shown that epigenetic mechanisms provide an "extra" layer of transcriptional control that regulates genes expression. Three distinct mechanisms appear intricately related in initiating and sustaining epigenetic modifications: RNA-associated silencing, DNA methylation and histone modification. These mechanisms are critical components in the normal development and cell growth. DNA methylation is involved in transcriptional silencing of genes, regulation of expression of imprinted genes, a number of tumour suppressor genes in cancer and silencing of genes located on the inactive X chromosome. In this review, we are focused on the basic principles of DNA methylation as the main epigenetic mechanism for normal embryonic development and epigenetic alterations that contribute to carcinogenesis

Dishevelled family proteins (DVL1-3) expression in IUGR placentas

Dishevelled family proteins (DVL1, DVL2, and DVL3) are cytoplasmic mediators involved in canonical and non-canonical Wnt signaling that are important in embryonic development. The role of DVL proteins in the placental tissue remains mostly unknown. In the current study, we explored the role of Dishevelled proteins in naturally invasive tissue, trophoblast. Formalin-fixed paraffin-embedded samples of 15 term placentas from physiologic term pregnancies and 15 term placentas from pregnancies complicated with intrauterine growth restrictions (IUGR) were used for the study. Expression levels of mRNA for DVL1, DVL2, and DVL3 in placentas were analyzed by quantitative real-time PCR (qRT-PCR). DVL1, DVL2, and DVL3 protein expression were semi-quantitatively analyzed using immunohistochemistry. The expression of DVL2 and DVL3 proteins was significantly higher in trophoblasts in placental villi from IUGR pregnancies compared with the control group of term placentas. In contrast, DVL3 protein expression was significantly higher in endothelial cells in placental villi from IUGR pregnancies compared with normal term placentas. The observed differences at protein levels between normal and IUGR placentas were not confirmed at the mRNA levels of DVL genes. Our data indicate the active involvement of DVL proteins in IUGR-related placentas. No significant changes were observed in DVL mRNA levels between the two groups of placentas. Further studies are required to explore the clinical relevance of these observations