Developmental Characteristics of the Glomerular and Tubular Portion of the Nephron in the Human Foetal Kidney Cortex: Morphometrical and Immunohistochemical Analysis.

This study aimed to morphometrically examine the development of glomeruli and tubules in the kidney cortex of human foetuses at different gestational ages (GAs). We also investigated the expression of the proliferation marker Ki-67 and apoptosis-related markers Bcl-2 and Bax during nephrogenesis using immunohistochemistry. Kidney samples from 38 human foetuses of both sexes with GA ranging from 13 to 40 weeks were analysed. The samples were divided into 7 groups based on GA, each corresponding to 1 lunar month. Foetal kidneys showed a spatiotemporal gradient of nephron differentiation with the transient stages of nephron anlage located in the nephrogenic zone and immature nephrons located in the subjacent maturation zone. In the inner cortex, nephrons establish the morphological characteristics of definitive nephrons. The average area, perimeter, and Feret's diameter of the glomeruli formed within the kidney cortex gradually decreased up to a period of 29-32 weeks of gestation and subsequently increased until a period of 37-40 weeks. There was a weak negative correlation with GA. In contrast, the areal density of glomeruli increased up to a period of 21-24 weeks and then gradually decreased until a period of 37-40 weeks, showing a moderate negative correlation with GA. The average area of renal tubules slightly decreased until a period of 21-24 weeks of gestation and then gradually increased until a period of 36-40 weeks, showing a moderate positive correlation with GA. The average areal density of renal tubules increased significantly until a period of 21-24 weeks of gestation, remained relatively constant until a period of 33-36 weeks, and then increased significantly at 36-40 weeks. There was a strong positive correlation with GA. Our results showed that Ki-67 was expressed in numerous cells of the metanephric mesenchyme, pretubular aggregates, renal vesicles, comma-shaped bodies, and early S-shaped bodies. During subsequent development and the spatial expansion of nephrons towards the mature zone, the expression of Ki-67 was markedly reduced. Similarly, Bcl-2 was strongly expressed in induced nephrogenic progenitor cells, pretubular aggregates, renal vesicles, and comma-shaped bodies. As vascularisation and maturation of the nephron proceeded, Bcl-2 staining became less intense and limited to the parietal layer of the Bowman's capsule and renal tubules. Weak Bax expression was observed in individual scattered cells within segments of the nephrons at all developmental stages. In the mature zone, more intense Bax staining was observed in the renal tubules.

Reliability and Versatility of Reverse Sural Island Neurofasciocutaneous Leg Flaps.

BACKGROUND: Distally based sural neurofasciocutaneous (NFC) flaps are a commonly used method for foot and ankle reconstruction given that they are much simpler and, at the same time, still efficient alternative to perforator flaps and free style free flaps. OBJECTIVE: This study aims to evaluate the reliability and versatility of reverse sural island NFC flaps as a powerful and efficient method that can be used for repair of lower leg skin defects. This method does not require microsurgical facilities or extensive training. METHODOLOGY: Patients with soft tissue defects of the distal third of the leg and ankle region received reverse sural island NFC flaps. Inclusion criteria included an absence of damage to the sural neurovascular axis or communicating perforators, absence of peripheral vascular disease, and the presence of soft tissue defects deep enough to expose tendon or bone. Patients were assessed for flap (defect) size, pedicle length and location of defects, postoperative flap survival rates, and complications. Donor sites were closed directly or skin grafted. RESULTS: Of 24 consecutive patient (20 male; 4 female), all flaps except 1 (4.16%), survived, although partial necrosis was observed in 2 patients (8.33%). The overall major complication rate was 12.50%. Epidermolysis was noted in 1 patient (4.16%). Three cases of transient venous congestion resolved without additional complications. The overall minor complication rate was 16.66%. Minimal complications were associated with healing of donor sites. CONCLUSIONS: Reverse sural island NFC flaps provide adequate and aesthetically very acceptable coverage of soft tissue defects of the distal lower leg and proximal foot with no functional impairment.

Association of Two Primitive Carotid-Basilar Anastomoses and Cerebrovascular Abnormalities on the Brain Base: A Case Report.

Simultaneous presence of the persistent primitive trigeminal artery and so-called intermediate communicating artery was discovered in a 77-year-old cadaver autopsied due to the myocardial infarction. Many vascular variants and abnormalities such as aplasia of the right vertebral artery (VA), presence of two right posterior cerebral arteries (PCAs), partial duplication of the right superior cerebellar artery, hypoplasia of the pre-communicating part (A1) of the right anterior cerebral artery and the right PCA of basilar origin, a special configuration of the anterior communicating artery (ACoA), and a small aneurysm at the right A1-ACoA junction were associated. The finding of an incipient cerebral aneurysm at the junction of the hypoplastic A1 and embryonal configuration of the ACoA in the eight decade of life indicates that its development was caused by long-term pressure of blood flow at branching points of this artery independent from its caliber. However, it is not yet clear whether the persistence of the first and/or the second carotid-basilar anastomoses in this case was the condition for an aplasia of one VA or vice versa.

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.

Stereological study of developing glomerular forms during human fetal kidney development.

BACKGROUND: Human fetal kidney development is a complex and stepwise process. The number, shape, size and distribution of glomeruli provide important information on kidney organization. The aim of this study was to quantify glomerular developing forms during human fetal kidney development using stereological methods. METHODS: Kidney tissue specimens of 40 human fetuses with gestational ages ranging from 9 to 40 weeks were analyzed. Specimens were divided into eight groups based on gestational age, each corresponding to 1 lunar month. Stereological methods were used at the light microscopy level to estimate volume, surface and numerical density of the glomerular developing forms. RESULTS: During gestation, nephrogenesis continually advanced, and the number of nephrons increased. Volume, surface and numerical densities of vesicular forms and S-shaped bodies decreased gradually in parallel with gradual increases in estimated stereological parameters for vascularized glomeruli. Volume density and surface density of vascularized glomeruli increased gradually during fetal kidney development, and numerical density increased until the seventh lunar month. A relative decrease in vascularized glomeruli per unit volume of cortex occurred during the last 3 lunar months. Nephrogenesis began to taper off by 32 weeks and was completed by 36 weeks of gestation. The last sample in which we observed vesicles was from a fetus aged 32 weeks, and the last sample with S-shaped bodies was from a fetus aged 36 weeks. CONCLUSIONS: The present study is one of few quantitative studies conducted on human kidney development. Knowledge of normal human kidney morphogenesis during development could be important for future medical practice. Events occurring during fetal life may have significant consequences later in life.

Oxidant and antioxidant status in experimental rat testis after testicular torsion/detorsion.

BACKGROUND: The aim of this study was to determine oxidative stress (OS) parameters after testicular torsion/detorsion in adult rats. MATERIALS AND METHODS: In this experimental study, male adult Wistar rats were divided into four groups, each consisting of seven animals: group I-one hour right testicular torsion with subsequent orchiectomy, group II-one hour right testicular torsion followed by detorsion, group III-unilateral right-sided orchiectomy without previous torsion and group IV-control. After 30 days, bilateral orchiectomies were performed in rats with both testes and unilateral orchiectomies in rats with single testicles. Parameters of OS were determined in testicular tissue and in plasma. RESULTS: Plasma concentrations of advanced oxidation protein products (AOPP) and thiobarbituric acid reactive substances (TBARS) were higher (p<0.05 and p<0.01, respectively), whilst the plasma concentration of the total sulfhydryl (T-SH)-groups was lower (p<0.05) in group I compared to the control group. Group II had higher plasma concentrations of AOPP compared to group IV (p<0.05), as well as significantly increased TBARS and decreased T-SH-group levels compared to groups III (p<0.05 and p<0.01, respectively) and IV (p<0.01, for both parameters). There were significant differences in OS markers between the ipsilateral and contralateral testis, as well as significant correlations among levels of both plasma and tissue markers of OS. CONCLUSION: The increase in TBARS levels seen throughout the experimental period indicated that OS development was caused by ischemia/reperfusion in the testicular tissue. The oxidant-antioxidant system of the testicular tissue was altered during torsion as well as detorsion.

Human bony jugular foramen: some additional morphological and morphometric features.

BACKGROUND: The jugular foramen, the bony opening on the basis of skull, is an opening through which pass the ninth, tenth, and eleventh cranial nerves, two dural sinuses, and the meningeal branches of the occipital and ascending pharyngeal arteries. The increasing use of modern diagnostic procedures and new surgical approaches has created a need for much more detailed anatomical studies and explanations. This article reveals some additional features. MATERIAL/METHODS: Fifty jugular foramina of skulls of persons of unknown age and gender were examined. The morphological characteristics of all the investigated jugular foramina were described, measured, and compared, taking into consideration their side. RESULTS: All quantitative mean values, except for the width of the anteromedial compartment, were greater on the right side; of these, the lengths and widths of the posterolateral compartment were significantly greater. The bipartite form of the jugular foramen dominated. Complete bony bridging of the jugular foramen was found in 24% of cases. There is no rule of simultaneous complete bony bridging of the jugular foramen and splitting of the hypoglossal canal. CONCLUSIONS: A detailed examination of the jugular foramen anatomy was performed. The main types of jugular foramina and the frequencies of bipartite or tripartite division were established. Several dimensions of the parts of the jugular foramen were measured. Some new data could provide important information about the anatomy of the jugular foramen for reliable surgical interventions in this area.

Age-related changes of the human fetal kidney size.

Early prenatal diagnostics and the importance of genetic counseling are of great interest for echosonographic evaluation of normal fetus anatomy. Development of the human fetal kidney runs through a series of continual and mutually dependent changes during which the kidney obtains its morphological and functional maturity. This study was created to estimate the changes in kidney size during gestation in fetuses from the 4th to the 10th lunar month, to evaluate the dynamics of their growth, as well as to establish the validity of the volume calculated from these dimensions. Serial measurements of kidney dimensions (length, width, thickness) were performed in 110 fetuses. Photomicrographs of kidneys from the 4th, 6th, 8th and 10th lunar months are also presented. On the basis of the results obtained by our examination, we concluded that the period from the 14th to 16th week of intrauterine life is the fastest period of kidney growth during fetal development. Using the ellipsoid formula for calculating the fetal renal volume offers an underestimation of about 32-33% on average. The importance of this study lies in determining the average fetal kidney dimensions, which could be used as standard values in obstetrics.

[Changes of the glomerular size during the human fetal kidney development].

INTRODUCTION: Newborns adaptation on postnatal conditions includes significant morphological and functional renal changes. Every kidney contains a constant number of nephrons, at the end of the nephrogenesis period, which extends from week 8 to 34 of gestation. Mature juxtamedullary nephrons possess higher filtration capacity than primitive superficial nephrons, which have insufficient vascularization. OBJECTIVE: The objective of the study was to calculate an average glomerular diameter in cortical zones of the kidney during development, to define periods of their most intensive growth, and to record differences of glomerular size between different cortical zones. METHOD: A total of 30 human fetal kidneys aged from IV to X lunar months were analyzed. Stereological methods were used for calculating the average glomerular diameter in superficial, intermediate and juxtamedullary zone of the kidney cortex. RESULTS: Glomeruli in the superficial cortical zone had the lowest average diameter. The average glomerular diameter continually increased from IV lunar month (0.057 +/- 0.004 mm) to X lunar month (0.082 +/- 0.004 mm), with highly significant correlation with gestational age (r=0.755; p<0.01). The average glomerular diameter in the intermediate zone increased from 0.081 +/- 0.004 mm (IV lunar month) to 0.096 +/- 0.004 mm (X lunar month) with low linear correlation with gestational age (r=0.161). Juxtamedullary glomeruli were the biggest ones. Their average diameter, during the IV LM ranged from 0.093 +/- 0.006 mm to 0.101 +/- 0.004 mm. In the newborns (X lunar month), juxtamedullary glomeruli had spherical structures with an average diameter of 0.103 +/- 0.004 mm, and low negative correlation (r=-0.032) with gestational age. In the IV and V lunar months of gestation, there was significant difference (p<0.01; p<0.05) between the average glomerular diameter in the different zones of the kidney cortex. CONCLUSION: Superficial glomeruli had the smallest diameter, while juxtamedullary glomeruli were the largest. The average glomerular diameter increased during intrauterine development in all zones, most intensive in the X lunar month. There was a significant difference of the glomeruli between different cortical zones in the young fetuses. Such significant difference receded as gestational age increased.

Quantitative analysis of the nephron during human fetal kidney development.

BACKGROUND: The development of human kidney is a complex process. The number, shape, size, and distribution of nephrons as functional units in a kidney, provide some important information about the organization of the kidney. The aim of this study was to extend the knowledge of the developing human kidney by studying nephrons in the kidney's cortex during gestation. METHODS: Kidney tissue specimens of 32 human fetuses, the gestational age from IV lunar month (LM IV) to LM X, were analysed. Specimens were divided in ten groups based on gestational age. Stereological methods were used at the light microscopic level to estimate the volume densities of the corpuscular and tubular components of the nephron in the cortex of the developing human kidney. RESULTS: Nephron polymorphism was the main characteristic of the human fetal kidney during development. In younger fetuses, just below the renal capsule, there was a wide nephrogenic zone. It contained the condensed mesenchyme and terminal ends of the ureteric bud. Nephrons, in the different stages of development, were located around the ureteric bud which branched in the cortical nephrogenic zone and induced nephrogenesis. More mature nephrons were located in the deeper part of the cortex, close to the juxta-medullary junction. During gestation, nephrogenesis continually advanced, and the number of nephrons increased. Glomeruli changed their size and shape, while the tubules changed their length and convolution. Renal cortex became wider and contained the more mature glomeruli and the more convoluted tubules. The volume density of the tubular component of the nephron increased continually from 10.53% (LM IVa) to 27.7% (LM X). Renal corpuscles changed their volume density irregularly during gestation, increasing from 13% (LM IVa) to 15.5% (LM IVb). During the increase of gestational age, the volume density of corpuscular component of the nephron decreased to 11.7% (LM VIII), then went on increasing until the end of the intrauterine development (LM X) when corpuscles occupied 16.73% of the cortical volume. The volume density of the developing nephrons (corpuscular and tubular portion) showed the significant positive correlation (r = 0.85; p<0.01) with gestational age. CONCLUSION: The present study was one of few quantitative studies of the human developing nephron. Knowledge about the normal development of the human kidney should be important for the future medical practice.

Evaluation of absolute volume of human fetal kidney's cortex and medulla during gestation.

BACKGROUND: Human fetal kidney is quite different from the mature kidney, both macroscopically and hystologically. Lobulated surface of the human fetal kidney reflects its inner organisation. AIM: To determine the fetal kidneys' volume according to the gestational age, to establish periods of their maximal and minimal growth and to compare these values for various gestational ages. METHODS: Forty five human fetal kidneys aged from IV to X lunar months were analyzed. Kidneys were divided into nine groups according to their gestational age. The volumes of cortex and medulla were determined using stereological methods. The results were statistically analyzed and the periods of significant growth of these structures were marked. RESULTS: Fetal kidney's cortex and medulla grew continually with a very high coefficient of linear correlation with crown-rump length. The cortex/medulla ratio was minimal in the first half of V lunar month, when medulla grew most rapidly and it was maximal immediately before birth, when cortex achieved its maximum. CONCLUSION: This study was an effort to provide some parameters which would help in the future investigations of the development of human fetal kidney.