Sladjana Ugrenović

Viral Infection in Renal Transplant Recipients

Viruses are among the most common causes of opportunistic infection after transplantation. The risk for viral infection is a function of the specific virus encountered, the intensity of immune suppression used to prevent graft rejection, and other host factors governing susceptibility. Although cytomegalovirus is the most common opportunistic pathogen seen in transplant recipients, numerous other viruses have also affected outcomes. In some cases, preventive measures such as pretransplant screening, prophylactic antiviral therapy, or posttransplant viral monitoring may limit the impact of these infections. Recent advances in laboratory monitoring and antiviral therapy have improved outcomes. Studies of viral latency, reactivation, and the cellular effects of viral infection will provide clues for future strategies in prevention and treatment of viral infections. This paper will summarize the major viral infections seen following transplant and discuss strategies for prevention and management of these potential pathogens.

Peculiarities of the sural nerve complex morphologic types in human fetuses

The sural nerve is the most frequently used sensory nerve in nerve transplantation. It can be transplanted alone or together with the other elements of the neurovascular stalk within the superficial sural flap. The aim of this study was to define the morphologic types of the sural nerve complex, as well as to describe their specific characteristics. Microdissection was performed on 100 human fetuses (200 calves) after 10% formalin fixation. Five morphologic types of sural nerve complex with different incidence were defined. Two morphologic types dominated: type I (58.5%) in which the sural nerve was formed by merging of a fibular communicating branch and the medial sural cutaneous nerve, and type III (26%) in which the medial sural cutaneous nerve took over the function of the sural nerve. Other morphologic variations were less common.

Similarities and dissimilarities of the blood supplies of the human sciatic, tibial, and common peroneal nerves

The aim was to investigate the arterial supply of the sciatic, tibial, and common peroneal nerves. Thirty‐six lower limbs of 18 human fetuses were studied. The fetuses had been fixed in buffered formalin and the blood vessels injected with barium sulfate. Fetal age ranged from 12 to 28 weeks of gestation. Microdissection of the fetal lower extremities was done under ×5 magnifying lenses. The sciatic nerves of 10 lower extremities were dissected and excised and radiographs taken. The extraneural arterial chain of the sciatic nerve was composed of 2–6 arterial branches of the inferior gluteal artery, the medial circumflex femoral artery, the perforating arteries, and the popliteal artery. The extraneural arterial chain of tibial nerve was composed of 2–5 arteries, which were branches of the popliteal, the peroneal, and the posterior tibial arteries. Radiographs showed the presence of complete intraneural arterial chains in the sciatic and tibial nerves, formed from anastomosing vessels. Dissection showed that, in 97.2% of the specimens, the common peroneal nerve was supplied only by one popliteal artery branch, the presence of which was confirmed radiologically. The sciatic and tibial nerves are supplied by numerous arterial branches of different origins, which provide for collateral circulation. In contrast, the common peroneal nerve is most frequently supplied only by one elongated longitudinal blood vessel, a branch of the popliteal artery. Such a vascular arrangement may make the common peroneal nerve less resistant to stretching and compression. Clin. Anat. 26:875–882, 2013.

Psammoma bodies - friends or foes of the aging choroid plexus.

Psammoma bodies are structures classified in the group of dystrophic calcifications, which occur in some kind of tumors and in choroid plexus during the aging process. Despite early discovery of their presence in choroid plexus stroma, mechanisms responsible for their formation remained unclear. Their presence in some kind of tumors was even more extensively studied, but significant breakthrough in the field of their etiology was not attained, too. However, till today correlation between their presence in tumors and aging is not established. Also, there are not any data about structural differences between ones found in tumors and ones found in choroid plexus. This might points to the assumption that besides the aging, some other causes might be involved in their formation in choroid plexus. Furthermore, it is contradictory that forms, like psammoma bodies, present in such malignant formations as tumors, represent quite benign phenomenon in choroid plexus. Literature data and the results of our previous researches revealed that there might be connections between, these, on the first sight quite different processes. Firstly, psammoma bodies are present in stroma of tumors with predominantly papillomatous morphology, which is present in choroid plexus, too. Initial forms of psammoma bodies might be formed in fibrovascular core of choroid plexus villi, similarly like in tumors papillae of papillary thyroid cancer. Their further growth leads to the progressive destruction of both tumors papillae and choroidal villi. Choroid plexus stroma is characterized by the fenestrated blood vessels presence, which are similar to newly formed vessels in tumors. This makes it vulnerable to the noxious agents from circulation. It can contain lymphocytes, macrophages, dendritic cells and myofibroblasts in cases with psammoma bodies, similarly to tumors stroma which is in activated, proinflammatory state. So, all these facts can suggest that similar processes can lead to psammoma bodies formation in both tumors and choroid plexus and, that they might have harmful effect on choroid plexus structure and function during the aging process. Significantly higher degree of choroidal epithelial cells atrophy, in cases with present psammoma bodies proves that partially. Further researches should be focused on detection of osteopontin and nanobacteria, already detected in tumors psammoma bodies, in choroid plexus ones. Discovery of choroidal psammoma bodies mechanisms formation can be important for elucidation of some aspects in pathogenesis of some tumors, too. Application of choroid plexus epithelial cells functional markers in cases with psammoma bodies should show their functional status.

Morphometric Analysis of Nonsclerosed Glomeruli Size and Connective Tissue Content during the Aging Process

Number of sclerotic glomeruli increases during the aging process. Consequently, majority of remained nonsclerosed glomeruli become hypertrophic and some of them sclerotic, too. The aim of this study was to quantify the size and connective tissue content of nonsclerosed glomeruli and to evaluate the percentage of hypertrophic ones in examined human cases during the aging. Material was right kidneys tissue of 30 cadavers obtained during routine autopsies. Cadavers were without previously diagnosed kidney disease, diabetes, hypertension, or any other systemic disease. Tissue specimens were routinely prepared for histological and morphometric analysis. Images of the histological slices were analyzed and captured under 400x magnification with digital camera. Further they were morphometrically and statistically analyzed with ImageJ and NCSS-PASS software. Multiple and linear regression of obtained morphometric parameters showed significant increase of glomerular connective tissue area and percentage. Cluster analysis showed the presence of two types of glomeruli. Second type was characterized with significantly larger size, connective tissue content, and significantly lower cellularity, in relation to the first type. Such glomeruli might be considered as hypertrophic. First type of glomeruli was predominant in younger cases, while second type of glomeruli was predominant in cases older than 55 years.

Extraneural Arterial Blood Vessels of Human Fetal Sciatic Nerve

Nerves get segmental blood supply either from the neighboring muscular and cutaneous branches or from the regional main arterial trunks. The aim of our research was to detect, in the gluteal and posterior femoral region, the blood vessels which are involved in the blood supply of the human fetal sciatic nerve, as well as to establish their origin. Micro-dissection was performed on 48 fetal lower extremities which were previously fixed in 10% formalin. Micropaque solution (barium sulfate) was injected into their blood vessels. The fetal gestational age was established by measuring the crump-crown length and it ranged from the third to the ninth lunar month. The observed nutritional arteries of the human sciatic nerve originated from the inferior gluteal artery, medial circumflex femoral artery, perforating branches, and popliteal artery. The anastomotic arterial chain of the human sciatic nerve was observed in all cases. In 75% of the cases it was composed of the branches of the inferior gluteal artery, the medial circumflex femoral artery and the first two perforating arteries. The nutrient branch of the third perforating branch was less frequently (in 14.5% of the cases) part of this anastomotic arterial chain.

Morphometric analysis of human sciatic nerve perineurial collagen type IV content

Objectives: Aging is the process which unavoidably alters structure and function of the basal membranes in humans. Though, collagen type IV presents the most prominent component of the basal membranes, we estimated its presence in the perineurium of the human sciatic nerve samples during the aging process. Materials and methods: Material was 12 sciatic nerve samples, obtained from cadavers whose age ranged from 36 to 84 years. Cadavers were classified into three age groups: first which age ranged from 35 to 54 years, second which age ranged from 55 to 74 years and third which included cases older than 75 years. Tissue slices were further stained by labeled streptavidin–biotin method with collagen type IV monoclonal antibody and analyzed with light microscope under 100× lens magnification with oil immersion. Digital images of sciatic nerve perineurium were further processed and analyzed with ImageJ software. Results: Our results showed that there is statistically significant increase of perineurial area, perimeter, collagen type IV area, and collagen type IV area per perineurial perimeter unit in the third age group. These parameters also increased in the second age group, but this increase was not significant. Multiple regression analysis showed that beside fascicular size, age more significantly predict perineurial collagen type IV content. Conclusions: Results of morphometric and statistical analysis pointed to the conclusion that there is significant increase of sciatic nerve perineurial thickness during the aging process. This increase might represent the consequence of perineurial collagen type IV deposition with aging. Microsc. Res. Tech., 2011.

The posterior part of the human cerebral arterial circle (CAC): arterial caliber from gestational weeks 13 to 24

Numerous studies have reported that all components of the cerebral arterial circle in the 4‐month‐old human fetus are more slender than adult vessels, and of equal caliber. After that period, a degree of caliber differentiation is present, especially at the level of the posterior communicating arteries. The aim of this study was to determine arterial diameters in the posterior part of the fetal cerebral arterial circle from the 4th month (IV) to the 6th (VI). One hundred and seventy‐two fetal cerebral arterial circles were examined by means of a surgical microscope. It was determined that average diameters of the left (right) pre‐communicating parts of the posterior cerebral artery ranged from 0.30 ± 0.03 (0.29 ± 0.02) mm in month IV, to 0.36 ± 0.04 (0.36 ± 0.03) mm during month V and up to 0.55 ± 0.22 (0.50 ± 0.18) mm in month VI. The average diameters of the left (right) posterior communicating artery ranged from 0.24 ± 0.02 mm (0.25 ± 0.02) in month IV, to 0.30 ± 0.03 mm (0.29 ± 0.05) during month V and up to 0.38 ± 0.08 (0.44 ± 0.10) in month VI. Gender differences between posterior cerebral artery and posterior communicating artery diameters were not significant. Average posterior cerebral artery diameters were significantly larger than posterior communicating artery diameters in months IV and V, but not in month VI. It was established that caliber differentiation in the posterior part of the cerebral arterial circle began from gestational month IV, and that gender differences in arterial diameters were not significant until month VI of gestation.

Morphometric analysis of the stylohyoid complex

PurposeStylohyoid complex is anatomical structure predisposed to numerous individual variations. These may result in its extreme elongation, medial deviation and finally Eagle’s syndrome occurrence. The aim of this study was to measure the length, angulation, evaluate morphological variations of stylohyoid complex by computed tomography and, subsequently, relate obtained data to the gender and the age of the evaluated cases.Materials and methodsThe material included CT scans of stylohyoid complexes of 282 individuals. The entire length, maximal thickness, and angulation of the stylohyoid complexes in the coronal, transverse, and sagittal planes were measured.ResultsAccording to their morphology, orientation and length, stylohyoid complexes were classified into six morphological types. Elongated, bent, segmented, and segmented with attached stylohyoid ligament for the lesser horns of the hyoid bone stylohyoid complex types were characterized by significantly greater length, while pseudoarticulated type was characterized by significantly lower length in relation to normal stylohyoid complex type. The elongated type was additionally significantly thicker and with significantly lower value of medial angle in transverse plain than the normal stylohyoid complex type. Elongated, bent, and segmented types were significantly more frequent in males than in females. Furthermore, the frequency of the elongated stylohyoid complex type increased, whereas normal and pseudoarticulated types decreased with age.ConclusionsIn conclusion, elongated and more medially deviated stylohyoid complexes are more frequent in males than in females. Their more frequent presence in the older age groups indirectly connects this phenomenon with the aging process.

The Infraorbital Artery in Fetuses: Clinical Relevance in Perforator Flap Surgery.

Introduction: The reconstruction of soft tissue detects in mid facial region are highly demanding. Most challenging region are nasal alla. For full thickness nasal alla defects most authors use nasolabial flap based on facial/angular arcade, but for recidivans tumors the infraorbital perforator flap is a good solution. Aim: The aim of our research was to analyze the number and the course of the infraorbital artery terminal branches. Material and methods: Material was 60 fetal hemifacial specimens of different gestational ages. Fetuses were fixed in 10% formalin and arterial blood vessels were injected with Micropaque solution (barium sulfate). Samples were further processed by Spalteholz technique, their images captured with digital camera and analyzed. Infraorbital artery was constant artery and had 2 to 4 terminal branches supplying infraorbital region. The majority of its terminal branches were characterized with descending course. Reach anatomical network of infraorbital artery made anastomoses with facial artery. Conclusion: Perforator flap based on infraorbital artery had well defined vascular supply with numerous soft tissue branches, which qualify this flap as safe solution for nasal reconstruction.