SVIBOR - Project code: 3-01-050

MINISTRY OF SCIENCE AND TECHNOLOGY

Strossmayerov trg 4, HR - 10000 ZAGREB
tel.: +385 1 459 44 44, fax: +385 1 459 44 69
E-mail: ured@znanost.hr

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Project code: 3-01-050

MORPHOLOGICAL AND STEREOLOGICAL INVESTIGATIONS OF EMBRYONIC SAC.

Main researcher: DURST-ŽIVKOVIĆ, BOSILJKA (11035)

Assistants

GRBEŠA, ĐURĐICA (94956)

Type of research: basic
Duration from: 01/01/91. to 12/31/93.

Papers on project (total): 20
Papers on project quoted in Current Contents: 4

Institution name: Medicinski fakultet, Zagreb (108)
Department/Institute: Department of Histology and Embryology, School of Medicine, Unib
Address: Šalata 3,
City: 10000 - Zagreb, Croatia

Communication: Fax: 385 (0)1 4566-795; Phone: 385 (0)1 4566-946; E-mail: davor @ mamef.mef.hr

Summary: The investigations were carried out to define various structural parameters in human placenta. The results demonstrated the following: In human term placentas statistically significant differences between the volume density of chorionic stems and their branches and terminal villi (P<0.01) have been found out, what also applies to their total volumes (P<0.02) as well as to their masses (P<0.01). Objectivitz of intervillous space measuring has been discussed. During maturation of placenta between the two observed periods of X lunar month (I. period from the 38th to 39th week /12 placentas/ and II. period in the 40th week /11 placentas/) the values of macroscopic measures in the newborns and placentas as well as quantitative parameters of parenchyma (surface density and total surface of terminal villi, mesenchyma and blood capillaries) do not change significantly. In syncytiotrophoblast the volume share of alpha zone is significantly higher in the I. period, while the volume share and the total volume of beta zones are significantly higher in the II. period (P<0.01). The surface density of alpha zones is significantly higher between the 38th and 39th week (P<0.01). It means that the differentiation of placental barrier is expressed by the enlarged surface of alpha zones, what affirms the assumption of functionally increased permeability in transcellular transport. The arrengement of alpha and beta zones in the placenta as a whole is even and regionaly independent. Beta zones prevail quantitatively. Alpha zones make up only 8% of the total volume, 18% of the total surface and 39% of the thickness of the beta zones. From the functional point of view the obtained results support the theory that in the last four weeks of pregnancy the growing physiological needs of fetus correspond to the structural changes of syncytiotrophoblast. At the beginning of this period of maturation, differentiation of trophoblast is indicated by domination of alpha zones, the areas responsible for transplacental gas exchange. The end of this period is characterized by the increased value of the beta zone i.e. with a metabolically active syncytial zone.Sexual dimorphisme in placenta is shown in alpha zone by a significantly higher volume density (P<0.002), total volume (P<0.05) and surface density (P<0.025) in placentas of female newborns. The fetoplacental index is higher in male newborns. By the electron-microscopic cytomorphological analysis of syncytiotrophoblast, beta zones were easily identified as segments with a thicker layer of cytoplasm and numerous nuclei, abundant cellular organelles, clusters of smooth-walled canaliculi, vesicules and basal infoldings. On the basis of these observations we consider that the cytomorphological differentiation of ultrastructural elements of beta zones is easily observable and we suppose that the quantitative analysis may be performed on electron micrographs by stereological methods in a technically appropriate way.

Keywords: embryonic sac, placenta (morphology, parenchyma, maturation, development, syncytiotrophoblast), stereology, embryonic membranes

Research goals: The object of this research is the embryonic sac i.e. the architecture of placenta and embryonic membranes. The homogenity of placental structure as a whole has been analysed and possible regional structural differences have been stated vertically from subchorionic to parabasal zone, and horizontally from the region of umbilical cord insertion to the edge of the organ. Structural changes during differentiation and maturation in chronological continuity were also estimated and compared. The field of reference is the parenchyma of placenta with all its structural elements: chorionic villi, its syncytiotrophoblast with differentiated parts (alpha and beta zones), placental barrier (membrane), mesenchymal stroma, chorionic blood vessels, placental fibrinoids and intervillous space. Morphological stereological light microscopic analysis include electron-microscopic level.

COOPERATION - PROJECTS

Name of project: 3-01-181 Rječnik medicinskog (humanog i veterinarskog) nazivlja.
Name of institution: Hrvatska akademija znanosti i umjetnosti.
City: 10000 - Zagreb, Croatia

Other information about the project.


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