Marija Bjelakovic

Development of c-kit immunopositive interstitial cells of Cajal in the human stomach.

Interstitial cells of Cajal (ICC) include several types of specialized cells within the musculature of the gastrointestinal tract (GIT). Some types of ICC act as pacemakers in the GIT musculature, whereas others are implicated in the modulation of enteric neurotransmission. Kit immunohistochemistry reliably identifies the location of these cells and provides information on changes in ICC distribution and density. Human stomach specimens were obtained from 7 embryos and 28 foetuses without gastrointestinal disorders. The specimens were 7–27 weeks of gestational age, and both sexes are represented in the sample. The specimens were exposed to anti‐c‐kit antibodies to investigate ICC differentiation. Enteric plexuses were immunohistochemically examined by using anti‐neuron specific enolase and the differentiation of smooth muscle cells (SMC) was studied with anti‐α smooth muscle actin and anti‐desmin antibodies. By week 7, c‐kit‐immunopositive precursors formed a layer in the outer stomach wall around myenteric plexus elements. Between 9 and 11 weeks some of these precursors differentiated into ICC. ICC at the myenteric plexus level differentiated first, followed by those within the muscle layer: between SMC, at the circular and longitudinal layers, and within connective tissue septa enveloping muscle bundles. In the fourth month, all subtypes of c‐kit‐immunoreactivity ICC which are necessary for the generation of slow waves and their transfer to SMC have been developed. These results may help elucidate the origin of ICC and the aetiology and pathogenesis of stomach motility disorders in neonates and young children that are associated with absence or decreased number of these cells.

Possible therapeutic use of spermatogonial stem cells in the treatment of male infertility: a brief overview.

Development of germ cells is a process starting in fetus and completed only in puberty. Spermatogonial stem cells maintain spermatogenesis throughout the reproductive life of mammals. They are undifferentiated cells defined by their ability to both self-renew and differentiate into mature spermatozoa. This self-renewal and differentiation in turn is tightly regulated by a combination of intrinsic gene expression as well as the extrinsic gene signals from the local tissue microenvironment. The human testis is prone to damage, either for therapeutic reasons or because of toxic agents from the environment. For preservation of fertility, patients who will undergo radiotherapy and/or chemotherapy have an attractive possibility to keep in store and afterwards make a transfer of spermatogonial stem cells. Germ cell transplantation is not yet ready for the human fertility clinic, but it may be reasonable for young cancer patients, with no other options to preserve their fertility. Whereas this technique has become an important research tool in rodents, a clinical application must still be regarded as experimental, and many aspects of the procedure need to be optimized prior to a clinical application in men. In future, a range of options for the preservation of male fertility will get a new significance.

Ultramorphological Characteristics of Podocyte Development in the Human Fetal Metanephros

The aim of this study was to determine the developmental characteristics of podocytes in the human fetal metanephros using scanning electron microscopy, light microscopy, and transmission electron microscopy. Kidney samples of 15 human fetuses of both sexes (gestational age 10–22 weeks) were analyzed. At the S-shaped body stage, primitive podocytes were arranged in a layer of cuboidal cells beneath the vascular cleft. When observed from Bowman’s space, the demarcation between adjacent podocytes was not clear, but mild depressions indicated cell boundaries. At the more advanced S-shaped body stage, podocytes were polygonal, with a flat apical surface. They were in close contact, but boundaries between adjacent cells were distinct. After initial separation of their apical parts, podocytes continued to separate from each other along their lateral sides. Their shape changed from polygonal to spherical, resembling clusters of grapes. Cytoplasmic buds could be seen at the base of some podocytes initially, when all podocytes were spherical. Parallel with the development of the first capillary loops, wider intercellular spaces were noted between elliptical-shaped podocytes. Podocytes then developed cytoplasmic processes and became flattened and star shaped. Their cell bodies separated from the glomerular basement membrane through the insertion of thick processes under the cell body. Thick primary processes ramified to form the foot processes, which interdigitated on the surface of capillary loops. During the capillary loop stage, the degree of differentiation of the podocytes varied among various glomerular regions, as well as within the same capillary loop.

ANAL YSIS OF THE ANAT OMICAL VARIATIONS OF THE SUPRAORBITAL TRANSCRANIAL PASSAGE IN SOU THEAST SERBIAN POPULATION O N VOLUME RENDERED CT SCANS

The aim of this study was to analyze the variability in the shape and number of supraorbital transcranial passages, supraorbital notch or foramen (SON/F) in southeast Serbian population using three-dimensional computer tomography (3D-CT) with the volume rendering and to evaluate these variations in relation to gender and side. One hundred and fifteen CT scans of adult subjects (59 men and 56 women) without any skull trauma or malformation, aged 21 to 83 years, were analyzed in our study. Of 230 supraorbital regions, a smooth supraorbital rim with absent SON/F was observed in 37.39%. The most common type of the supraorbital passage was single SON (53.48%). Single SOF was found in 5.22% and incomplete SOF in 0.44%. The frequency of double SON was 1.30%, double SOF 0.87% and SON with SOF on the same side was 1.30%. There was no statistically significant difference between genders and sides (p˃0.05). Fourteen various combinations of different types were observed in our material. The most common combination was bilateral SON (33.91%) and bilateral absence of SON/F (20.87%). A very frequent combination was SON on one side and the absence of SON/F on the contralateral side (32.17%). Other combinations of types were rare. The knowledge of the frequency of the types of supraorbital transcranial passages and their bilateral distribution may be helpful for clinicians in anticipating the exit point of the supraorbital neurovascular bundle during surgical procedures and planning of local anesthesia. Acta Medica Medianae 2017;56(3):81-87.