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Tubules
Kinds of Tubules Terms modified by Tubules Selected AbstractsDevelopmental Changes of Seminiferous Tubule in Prenatal, Postnatal and Adult Testis of Bonnet Monkey (Macaca radiata)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2008S. Prakash Summary This paper is a part of our study on the male reproductive system of bonnet monkey. The developmental changes in testis of bonnet monkey were studied qualitatively and quantitatively, at the light microscopy level. Testicular development appears to primarily involve tubular growth that starts immediately after birth. There is a gradual increase in the number of tubules in the prenatal to neonatal stage in testis, without an increase in the volume. Increase in the number of tubules in the neonatal testis was achieved by an increase in the length of the tubules and reduction in the interstitial proportion. Scattered spermatogonial cells in the tubules of neonatal testis indicate the rapid growth rate of the tubules. Increase in tubular length along with diameter seems to be a continuous process until puberty. This is the first report on the developmental changes in the testis during fetal, postnatal and adult stages in the bonnet monkey. [source] Tubulitis and Epithelial Cell Alterations in Mouse Kidney Transplant Rejection Are Independent of CD103, Perforin or Granzymes A/BAMERICAN JOURNAL OF TRANSPLANTATION, Issue 9 2006G. Einecke One of the defining lesions of kidney allograft rejection is epithelial deterioration and invasion by inflammatory cells (tubulitis). We examined epithelial changes and their relationship to effector T cells and to CD103/E-cadherin interactions in mouse kidney allografts. Rejecting allografts showed interstitial mononuclear infiltration from day 5. Loss of epithelial mass, estimated by tubular surface area, and tubulitis were minimal through day 7 and severe by day 21. Tubules in day 21 allografts manifested severe reduction of E-cadherin and Ksp-cadherin by immunostaining with redistribution to the apical membrane, indicating loss of polarity. By flow cytometry T cells isolated from allografts were 25% CD103+. Laser capture microdissection and RT-PCR showed increased CD103 mRNA in the interstitium and tubules. However, allografts in hosts lacking CD103 developed tubulitis, cadherin loss, and epithelial deterioration similar to wild-type hosts. The loss of cadherins and epithelial mass was also independent of perforin and granzymes A and B. Thus rejection is characterized by severe tubular deterioration associated with CD103+ T cells but not mediated by CD103/cadherin interactions or granzyme-perforin cytotoxic mechanisms. We suggest that alloimmune effector T cells mediate epithelial injury by contact-independent mechanisms related to delayed type hypersensitivity, followed by invasion of the altered epithelium to produce tubulitis. [source] Catanionic Tubules with Tunable Charge,ANGEWANDTE CHEMIE, Issue 37 2010Nicola Manghisi Dr. Positiv und negativ in der Waage: Ein neuartiges Verhalten im Bereich katanionischer Systeme wurde in Lösungen von anionischen und kationischen Formen starrer, ungewöhnlicher Amphiphile beobachtet. Verdünnte wässrige Mischungen von anionischen und kationischen Gallensäure-Derivaten bilden katanionische Röhren, deren Ladung durch das Molverhältnis der Tenside in der Mischung bestimmt wird. [source] Histological evidences suggest recommending orchiopexy within the first year of life for children with unilateral inguinal cryptorchid testisINTERNATIONAL JOURNAL OF UROLOGY, Issue 7 2007Kwan Hyun Park Objective: To determine the optimal timing for orchiopexy, we evaluated the histological parameters of the cryptorchid testis. Methods: We prospectively performed testicular biopsy in a total of 65 consecutive children with palpable unilateral inguinal cryptorchid testes. For controls, we used testicular histological slides from 15 age-matched children with testicular tumor. To investigate the fertility potential, we analyzed the parameters including mean tubular diameter (MTD), mean tubular fertility index (MTFI), germ cell count/tubule (GCC), Sertoli cell index (SCI) and interstitial fibrosis index (IFI). Results: The MTFI and GCC in children ,1 years of age were significantly higher than those of other older age groups. The MTFI, GCC and IFI were significantly better in patients ,2 years of age when compared to those of > 2 years. Compared to the controls, the MTFI and GCC in the patients were significantly worse in those aged > 2 years at surgical repair. In the ,2-year age group, the MTFI and GCC of the cryptorchid testis showed a decreasing tendency with age, which were contrasting with the ascending curves in the control and the curves crossed at 1,2 years of age in each parameter. Conclusions: To protect fertility potential, we recommend, orchiopexy should be performed within the first year of life, and no later than 2 years of age in patients with palpable inguinal cryptorchid testes. [source] Infertility despite surgery for cryptorchidism in childhood can be classified by patients with normal or elevated follicle-stimulating hormone and identified at orchidopexyBJU INTERNATIONAL, Issue 7 2003D. Cortes OBJECTIVE To analyse infertility despite orchidopexy in childhood. PATIENTS AND METHODS The study comprised patients with cryptorchidism (70 bilateral and 65 unilateral) who had a simultaneous biopsy taken at orchidopexy in childhood, and in adulthood had analyses of semen and FSH. In adulthood 42 formerly bilateral cryptorchid boys had repeat testicular biopsies taken. Infertility was suspected in men with < 5 million sperm/mL in the best sample of semen and concomitant poor sperm motility, and who were classified by follicle-stimulating hormone (FSH) values. At orchidopexy the number of spermatogonia/tubule and the germ cell differentiation were measured. In adulthood the percentage of tubules with complete spermatogenesis, spermatogenic arrest and Sertoli-cell only status was assessed. RESULTS Infertility was suspected in 38 of 70 (54%) of formerly bilateral and six of 65 (9%) formerly unilateral cryptorchid patients. High FSH values were expected in these suspected infertile patients, but 15 of 38 (59%) formerly bilateral and five of six formerly unilateral cryptorchid patients had normal FSH values. These patients were identified in childhood at orchidopexy; those with bilateral cryptorchidism generally presented with germ cells, but the mean number of spermatogonia per tubule was < 30% of the lowest normal value, and the germ cells were seldom normally differentiated, whereas those with unilateral cryptorchidism generally lacked germ cells in the biopsies. No patients had a decreased FSH value. CONCLUSION Despite surgery for cryptorchidism, infertility was probable in a third (44 of 135) of the patients. We expected high FSH values in these patients, but in 45% (20/44) the FSH values were normal. These patients may have relative FSH deficiency. At orchidopexy these patients were identified to be bilaterally cryptorchid with few germ cells and those unilaterally cryptorchid had none in the biopsy. After orchidopexy in childhood, additional hormonal treatment, e.g. recombinant FSH or buserelin, may be indicated in these patients. [source] Tubular reabsorption and diabetes-induced glomerular hyperfiltrationACTA PHYSIOLOGICA, Issue 1 2010P. Persson Abstract Elevated glomerular filtration rate (GFR) is a common observation in early diabetes mellitus and closely correlates with the progression of diabetic nephropathy. Hyperfiltration has been explained to be the result of a reduced load of sodium and chloride passing macula densa, secondarily to an increased proximal reabsorption of glucose and sodium by the sodium-glucose co-transporters. This results in an inactivation of the tubuloglomerular feedback (TGF), leading to a reduced afferent arteriolar vasoconstriction and subsequently an increase in GFR. This hypothesis has recently been questioned due to the observation that adenosine A1 -receptor knockout mice, previously shown to lack a functional TGF mechanism, still display a pronounced hyperfiltration when diabetes is induced. Leyssac demonstrated in the 1960s (Acta Physiol Scand58, 1963:236) that GFR and proximal reabsorption can work independently of each other. Furthermore, by the use of micropuncture technique a reduced hydrostatic pressure in Bowman's space or in the proximal tubule of diabetic rats has been observed. A reduced pressure in Bowman's space will increase the pressure gradient over the filtration barrier and can contribute to the development of diabetic hyperfiltration. When inhibiting proximal reabsorption with a carbonic anhydrase inhibitor, GFR decreases and proximal tubular pressure increases. Measuring intratubular pressure allows a sufficient time resolution to reveal that net filtration pressure decreases before TGF is activated which highlights the importance of intratubular pressure as a regulator of GFR. Taken together, these results imply that the reduced intratubular pressure observed in diabetes might be crucial for the development of glomerular hyperfiltration. [source] The lateral intercellular space as osmotic coupling compartment in isotonic transportACTA PHYSIOLOGICA, Issue 1 2009E. H. Larsen Abstract Solute-coupled water transport and isotonic transport are basic functions of low- and high-resistance epithelia. These functions are studied with the epithelium bathed on the two sides with physiological saline of similar composition. Hence, at transepithelial equilibrium water enters the epithelial cells from both sides, and with the reflection coefficient of tight junction being larger than that of the interspace basement membrane, all of the water leaves the epithelium through the interspace basement membrane. The common design of transporting epithelia leads to the theory that an osmotic coupling of water absorption to ion flow is energized by lateral Na+/K+ pumps. We show that the theory accounts quantitatively for steady- and time dependent states of solute-coupled fluid uptake by toad skin epithelium. Our experimental results exclude definitively three alternative theories of epithelial solute,water coupling: stoichiometric coupling at the molecular level by transport proteins like SGLT1, electro-osmosis and a ,junctional fluid transfer mechanism'. Convection-diffusion out of the lateral space constitutes the fundamental problem of isotonic transport by making the emerging fluid hypertonic relative to the fluid in the lateral intercellular space. In the Na+ recirculation theory the ,surplus of solutes' is returned to the lateral space via the cells energized by the lateral Na+/K+ pumps. We show that this theory accounts quantitatively for isotonic and hypotonic transport at transepithelial osmotic equilibrium as observed in toad skin epithelium in vitro. Our conclusions are further developed for discussing their application to solute,solvent coupling in other vertebrate epithelia such as small intestine, proximal tubule of glomerular kidney and gallbladder. Evidence is discussed that the Na+ recirculation theory is not irreconcilable with the wide range of metabolic cost of Na+ transport observed in fluid-transporting epithelia. [source] Na+/H+ exchangers and the regulation of volumeACTA PHYSIOLOGICA, Issue 1-2 2006R. T. Alexander Abstract The regulation of volume is fundamental to life. There exist numerous conditions that can produce perturbations of cell volume. The cell has developed mechanisms to directly counteract these perturbations so as to maintain its physiological volume. Directed influx of the major extracellular cation, sodium, serves to counteract a decreased cell volume through the subsequent osmotically coupled movement of water to the intracellular space. This process, termed regulatory volume increase is often mediated by the ubiquitous sodium/hydrogen ion exchanger, NHE1. Similarly, the maintenance of intravascular volume is essential for the maintenance of blood pressure and consequently the proper perfusion of vital organs. Numerous mechanisms exist to counterbalance alterations in intravascular volume, not the least of which is the renal absorption of sodium filtered at the glomerulus. Two-thirds of filtered sodium and water are absorbed in the renal proximal tubule, a mechanism that intimately involves the apical sodium/hydrogen ion exchanger, NHE3. This isoform is fundamental to the maintenance and regulation of intravascular volume and blood pressure. In this article, the effects of cell volume on the activity of these different isoforms, NHE1 and NHE3, will be described and the consequences of their activity on intracellular and intravascular volume will be explored. [source] Topiramate-induced metabolic acidosis: report of two casesDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 10 2001Chun-hung Ko MRCP FHKAM Medical Officer Two children who presented with symptomatic metabolic acidosis after being put on topiramate (TPM) are reported. The first patient was an 11-year-old male with refractory complex partial epilepsy who was put on TPM for 13 months. He developed hyperventilation 1 week after increasing the dose to 300mg/day. Arterial blood gas revealed hyperchloraemic metabolic acidosis with partial respiratory compensation: pH 7.36, PCO2 27.2 mmHg, bicarbonate 14.9 mEq/L, base excess -8.9 mmol/L. Hyperventilation and acidosis resolved after administration of sodium bicarbonate and reduction of the dose of TPM. The second patient was a female who developed increasing irritability at age 16 months and 21 months, each time associated with introduction of TPM and resolved promptly upon withdrawal of the drug. Venous blood gas taken during the second episode revealed pH 7.34, PCO2 37.4 mmHg, bicarbonate 20.4 mEq/L, base excess -4.2 mmol/L. The predominant mechanism of TPM-induced hyperventilation involves inhibition of carbonic anhydrase at the proximal renal tubule, resulting in impaired proximal bicarbonate reabsorption. The occurrence of hyperpnoea or mental status change in any patient who is on TPM should prompt an urgent blood gas sampling, with correction of the acid-base disturbances accordingly. [source] Time course of the renal functional response to partial nephrectomy: measurements in conscious ratsEXPERIMENTAL PHYSIOLOGY, Issue 1 2007R. M. Chamberlain Previous investigations into the functional responses of the surviving nephrons following reductions in renal mass have been performed largely in anaesthetized animals and have taken little account of how the compensatory changes develop with time. The present study has assessed a method for determining glomerular filtration rate (GFR) in unrestrained, uncatheterized, conscious rats (plasma disappearance of 99mTc-diethylenetriamene pentaacetic acid (DTPA)) and has used this method to document the time course of the changes in GFR over a 32 day period following uninephrectomy or 5/6 nephrectomy. Concurrent measurements of excretion rates and of the clearance of lithium (the latter being an index of end-proximal fluid delivery) provided information on changes in overall tubular function and segmental reabsorption. After uninephrectomy, the GFR of the remaining kidney (compared with that of a single kidney of sham-operated animals) increased maximally (by ,50%) within 8 days; after 5/6 nephrectomy, the increase in the GFR of the remnant kidney was maximal (at ,300%) within 16 days. Overall excretion rates of sodium and potassium were well maintained in partially nephrectomized animals throughout the period of study, while the excretion of water increased (by ,30% after uninephrectomy and by ,120% after 5/6 nephrectomy), partly as a result of the compensatory increases in GFR but mainly as a consequence of moderate (after uninephrectomy) or marked (after 5/6 nephrectomy) reductions in fractional reabsorption. During the early period after 5/6 nephrectomy, potassium excretion sometimes exceeded the filtered load, indicating net secretion. Lithium clearance data indicated that the changes in tubular function after 5/6 nephrectomy include a reduction in fractional reabsorption in the proximal tubule, whereas after uninephrectomy any such effect on the proximal tubule is minor and transient. [source] Fibroblast growth factor 23 reduces expression of type IIa Na+/Pi co-transporter by signaling through a receptor functionally distinct from the known FGFRs in opossum kidney cellsGENES TO CELLS, Issue 5 2005Xiaomei Yan Fibroblast growth factor (FGF) 23 is an important phosphaturic factor that inhibits inorganic phosphate (Pi) reabsorption from the renal proximal tubule. Its overproduction and proteolysis-resistant mutation such as R179Q cause tumor-induced osteomalacia and autosomal dominant hypophosphatemic rickets, respectively. To clarify the signaling mechanisms of FGF23 that mediate the reduction of Pi reabsorption, we inhibited the function of the known FGFRs in opossum kidney (OK-E) cells by expressing a dominant-negative (DN) form of FGFR. OK-E cells, which represent the renal proximal tubular cells, expressed all four known FGFRs. FGF23(R179Q) bound to and activated FGFR2, a prominent FGFR expressed in OK-E cells. The activated receptor transmitted a signal to increase the expression of type IIa Na+/Pi co-transporter and the Pi uptake. Expression of FGFR2(DN), which suppresses the major FGFR-mediated signal through the FRS2,-ERK pathway, reversed the function of FGF23(R179Q). When FGF23(R179Q) was applied to the basolateral side of polarized OK-E cells, regardless of the FGFR2(DN) expression, the apical Pi uptake decreased significantly. The apical application of FGF23(R179Q) in the polarized cells did not show such decrease but increase. The exogenously expressed FGFR2 was detectable only at the apical membrane. These results suggest that an FGF23 receptor, which is functionally distinct from the known FGFRs, is expressed at the basolateral membrane of OK-E cells. [source] Identification of two cDNAs encoding synaptic vesicle protein 2 (SV2)-like proteins from epithelial tissues in the cat flea, Ctenocephalides felisINSECT MOLECULAR BIOLOGY, Issue 3 2004S. J. Walmsley Abstract Two distinct cDNAs that appear to encode proteins in the synaptic vesicle-2 (SV2) family were identified as expressed sequence tags from a Ctenocephalides felis hindgut and Malpighian tubule (HMT) cDNA library. To date, SV2 proteins have been described only in vertebrates, and have been detected only in synaptic vesicles in neuronal and endocrine tissues, where they are thought to regulate synaptic vesicle exocytosis. The cDNAs for the C. felis SV2-like proteins SVLP-1 and SVLP-2 encode predicted full-length proteins of 530 and 726 amino acids, respectively. Of characterized proteins, the SVLP protein sequences were most similar to rat SV2B. Northern blot analysis revealed that both mRNAs were up-regulated in larval stages that feed and in adults after feeding, and were expressed primarily or exclusively in the HMT tissues in adult fleas. These results suggest that the flea SVLP-1 and SVLP-2 gene products may have roles that are specific for the HMT tissues, and may differ in function from vertebrate SV2 proteins. [source] Dynamic expression of the prion-like protein Doppel in ovine testicular tissueINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 3 2006Arild Espenes Summary Transgenic knockout of the gene encoding the prion-like protein Doppel (Dpl) leads to male infertility in mice. The precise role of Dpl in male fertility is still unclear, but sperm from Dpl-deficient mice appear to be unable to undergo the normal acrosome reaction that is necessary to penetrate the zona pellucida of the ovum. We have investigated the expression pattern and some biochemical properties of Dpl in sheep testicular tissue and spermatozoa. Neither the Dpl protein nor its mRNA was detected in pre-pubertal sheep testis. This was in contrast to the findings in adult rams where both Dpl mRNA and protein were present. The molecular mass and glycosylation pattern of sheep Dpl were similar to that of mice Dpl. The Dpl protein was detected in the seminiferous epithelium during the two final (7 and 8) and the two initial (1 and 2) stages of the spermatogenic cycle in a characteristic pattern. In stage 8, an intense brim of granular Dpl-immunoreactivity associated with maturation phase spermatids was observed, while after the release of spermatozoa in stages 1 and 2, the Dpl-staining was disseminated more diffusely in the epithelium, reaching the basal lamina. From stage 3 to stage 6, Dpl-immunoreactivity could not be detected, indicating that the Dpl protein had disappeared between stages 2 and 3. Dpl was not detected on ejaculated spermatozoa. These patterns of staining indicate that Dpl is enriched in residual bodies, which are phagocytosed and destroyed by Sertoli cells after release of sperm into the lumen of the seminiferous tubule. [source] IL-10 is highly expressed in the cryptorchid cryptepididymal epithelium: a probable mechanism preventing immune responses against autoantigenic spermatozoa in the epididymal tubuleINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 3 2002E. Veräjänkorva The expression of several immunoregulatory adhesion proteins and cytokines was studied in the normal epididymis, cryptorchid cryptepididymis, the epididymis of oestrogen-treated mice and the epididymis of non-obese diabetic (NOD) mice at the protein level to see which of these immunoregulatory proteins may be involved in lymphocyte regulation in the normal or pathological epididymis and if cytokine balance in this organ is on the cellular or humoral side. The aim of the study was to characterize the immunological microenvironment of the epididymis to explain the survival of the autoantigenic spermatozoa in this site. In the 6-week-old BALB/c or NOD mouse epididymis there were some CD18 and CD44 expressing cells in the interstitial tissue. There were no differences between these strains in the expression of the studied antigens, except that some CD4 positive cells were present in the interstitial tissue of BALB/c mice. In the cryptorchid cryptepididymis CD4, CD8, CD18, CD44, CD54 and CD106 expressing cells were occasionally present in the connective tissue surrounding the epididymal tubule. In the epididymis of the oestrogen-treated mice these antigens were not expressed. In the cryptorchid cryptepididymis the epithelial cells expressed IL-10 highly and the myoid peritubular cells IL-6. The present results suggest that the epididymal epithelial IL-10 suppressing TH0, TH1 and TH2 immune responses may be involved in the protection of autoantigenic spermatozoa from immune destruction. [source] Low-grade renal epithelial tumor originating from the distal nephronINTERNATIONAL JOURNAL OF UROLOGY, Issue 2 2004NOBORU HARA Abstract, There are few published reports of low-grade renal epithelial tumor originating from the distal nephron. However, it should not be disregarded clinically, because the actual number of patients with such tumors may be higher than expected. We investigated the immunohistochemical profile of a histologically distinct subtype of such a tumor in detail, in addition to the clinical course and imaging studies. The present study demonstrated that both glandular and spindle cell components of this tumor have a persistent characteristic of an epithelial tumor arising from the distal tubule or collecting duct. This tumor is a benign complex neoplasm that can be treated successfully with radical surgery. Beta-catenin and E-cadherin are suggested to play a crucial role in tumorigenesis and the biphasic arrangement of this neoplasm, concerning the expression of epithelial membrane antigen and carbohydrate antigen 19-9. We suggest that the term ,distal nephron epithelioma' is appropriate for classifying such rare but clinicopathologically distinct tumors. [source] Alterations in renal cilium length during transient complete ureteral obstruction in the mouseJOURNAL OF ANATOMY, Issue 2 2008Leanne Wang Abstract The renal cilium is a non-motile sensory organelle that has been implicated in the control of epithelial phenotype in the kidney. The contribution of renal cilium defects to cystic kidney disease has been the subject of intense study. However, very little is known of the behaviour of this organelle during renal injury and repair. Here we investigate the distribution and dimensions of renal cilia in a mouse model of unilateral ureteral obstruction and reversal of ureteral obstruction. An approximate doubling in the length of renal cilia was observed throughout the nephron and collecting duct of the kidney after 10 days of unilateral ureteral obstruction. A normalization of cilium length was observed during the resolution of renal injury that occurs following the release of ureteral obstruction. Thus variations in the length of the renal cilium appear to be a previously unappreciated indicator of the status of renal injury and repair. Furthermore, increased cilium length following renal injury has implications for the specification of epithelial phenotype during repair of the renal tubule and duct. [source] Origin and development of the pronephros in the chick embryoJOURNAL OF ANATOMY, Issue 6 2003Tamiko Hiruma Abstract The process by which the pronephros develops was morphologically examined in chick embryos from Hamburger,Hamilton stage (ST) 8+ to ST34. The intermediate mesoderm, from which the pronephros arises, was first seen as a faint ridge of undifferentiated mesoderm between the segmental plate and lateral plate at ST8+. It formed a cell cord at the level of the 6th to the presumptive 13th somites at ST9 to ST10. This cell cord then separated into dorsal and ventral parts, the former becoming the nephric duct and the latter the tubules by ST14. The primordia of the external glomeruli (PEGs) appeared at ST15 through some epithelial cells protruding in the nephrostome (the opening of the nephric tubule into the body cavity). PEGs formed gradually in the caudal direction until ST18, while the pronephric tubules and PEGs in cranial locations disappeared. At this stage, only a few PEGs remained at the level of the 13th and 14th somites and these developed from ST23 to ST29 to become ultrastructurally similar to the glomeruli of the functional kidney. From these observations in the avian pronephros, we infer that the pronephric duct and tubules both form from a cell cord in the intermediate mesoderm and at the same time, but later develop differently. [source] Novel identification of peripheral dopaminergic D2 receptor in male germ cells,JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2007Carola Otth Abstract Dopamine is a recognized modulator in the central nervous system (CNS) and peripheral organ functions. The presence of peripheral dopamine receptors outside the CNS has suggested an intriguing interaction between the nervous system and other functional systems, such as the reproductive system. In the present study we analyzed the expression of D2R receptors in rat testis, rat spermatogenic cells and spermatozoa, in different mammals. The RT-PCR analysis of rat testis mRNA showed specific bands corresponding to the two dopamine receptor D2R (L and S) isoforms previously described in the brain. Using Western blot analysis, we confirmed that the protein is present in rat testis, isolated spermatogenic cells and also in spermatozoa of a range of different mammals, such as rat, mouse, bull, and human. The immunohistochemistry analysis of rat adult testis showed that the receptor was expressed in all germ cells (pre- and post-meiotic phase) of the tubule with staining predominant in spermatogonia. Confocal analysis by indirect immunofluorescence revealed that in non-capacitated spermatozoa of rat, mouse, bull, and human, D2R is mainly localized in the flagellum, and is also observed in the acrosomal region of the sperm head (except in human spermatozoa). Our findings demonstrate that the two D2 receptor isoforms are expressed in rat testis and that the receptor protein is present in different mammalian spermatozoa. The presence of D2R receptors in male germ cells implies new and unsuspected roles for dopamine signaling in testicular and sperm physiology. J. Cell. Biochem. 100: 141,150, 2007. © 2006 Wiley-Liss, Inc. [source] Comparison of testes structure, spermatogenesis, and spermatocytogenesis in young, aging, and hybrid cichlid fish (Cichlidae, Teleostei)JOURNAL OF MORPHOLOGY, Issue 3 2003Lev Fishelson Abstract Testis structure, spermatogenesis, and spermatocytogenesis were compared in 13 species of cichlid fishes, belonging to the subfamilies Haplochrominae and Tilapinae. The species studied were either mouth brooders, in which fertilization occurs mostly inside the mouth of the brooding fish, or substrate brooders, whose eggs adhere to a substrate over which the sperm is ejaculated. In this study, the embryogenesis of testes anlagen and sperm production was followed in embryos and in fish up to 15 years old, as well as in hybrids of the two subfamilies. In cichlids, the testes are of the unrestricted type and primary spermatogonia develop along the entire length of the developing sperm tubule. The first primary spermatogonia are observed in the testes anlagen 2,5 days after fertilization and they continue to develop in cysts formed by the enveloping Sertoli cells and the intertubular elements. The dimensions of such primary and secondary spermatocysts are correlated with the number of spermatogonia they contain and the corresponding number of mitotic multiplications. The largest mature cysts attained 300 ,m, and contained 2,200,2,400 spermatids in the mouth-brooding species and 2,600,3,200 in the substrate-brooding species. Despite the fact that in such cysts cytoplasmic bridges connect only the isogamete spermatids, the maturation of all cells and consequent spermiation is synchronized. Meristic characters distinguish the sperm of mouth brooders from those of substrate brooders, especially in the number of mitochondria and length of the flagellum. In older fish and hybrids, various changes can be seen in the gametogenic epithelium and intertubular cells. These include thickening of the connective tissue, formation of "yellow" groups of Leydig cells, cell apoptosis and degeneration, and, especially, formation of large spermatogonia, with large, electron-dense nucleoli, that have the cytological characteristics of oocytes. The intra- and interspecific variability of sperm dimensions in the studied cichlids poses an interesting question in the context of sperm competition. J. Morphol. 256:285,300, 2003. © 2003 Wiley-Liss, Inc. [source] Molecular Reproduction & Development: Volume 77, Issue 4MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 4 2010Article first published online: 23 FEB 2010 Immunofluorescence image of porcine seminiferous tubule with acetylated alpha tubulin (red), beta tubulin (green) and DNA (blue). See Luo et al. (this issue) for the dynamic profile of reversible tubulin acetylation during spermatogenesis. [source] Identification, isolation, and RT-PCR analysis of single stage-specific spermatogenetic cells obtained from portions of seminiferous tubules classified by transillumination microscopyMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 12 2009Chiara Vasco The protocol here described allows the analysis of gene expression in single specific mouse spermatogenetic cells. Germ cells were singularly isolated by microdissection of portions of seminiferous tubules classified, based on their transillumination pattern, into four distinct zones along their length. Single portions of a seminiferous tubule, corresponding to specific zones, were mechanically disaggregated into single cells that were (1) identified as spermatogonia, spermatocytes, round or elongated spermatids, (2) isolated using a micromanipulator, and (3) singularly transferred into a test tube for retro-transcription PCR analysis. On each single isolated cell, we have determined the quantitative profile of expression of Gapdh, an endogenous housekeeping gene known to be expressed throughout spermatogenesis. The protocol described allows an accurate analysis of the temporal and quantitative profile of gene expression throughout the whole male gamete differentiation process which so far has mainly been performed on enriched population of cells. Mol. Reprod. Dev. 76: 1173,1177, 2009. © 2009 Wiley-Liss, Inc. [source] Cell-cycle regulation and mammalian gametogenesis: A lesson from the unexpectedMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 8 2006Abraham L. Kierszenbaum Abstract The progression of mammalian gametogenesis requires a precise balance between cell-cycle activities and elimination of defective gametogenic cells to ensure the perpetuation of species. Both spermatogonia and oogonia are stem cell populations committed to meiosis with the aim of generating haploid gametes for fertilization. At puberty, mitotically dividing spermatogonial cell cohorts maintain the ability of cell renewal and occupy niches in the seminiferous tubule. In contrast, mitotically dividing oogonial cell cohorts produced in the fetal ovary, are exclusively committed to meiosis and produce primordial follicles housing a primary oocyte surrounded by somatic follicular cells. A consistent physiological event during mammalian gametogenesis is the disposal of spermatogenic cells by apoptosis and ovarian follicles by atresia. Cyclin-dependent kinases (Cdks) and their cyclin partners coordinate the activities of the cell cycle. An additional cell-cycle regulatory component is the centrosome. The centrosome harbors regulatory proteins controlling the normal progression of the cell cycle. Changes in individual centrosome proteins can lead to cell-cycle arrest and a decrease in the genomic protective function of p53 that promotes apoptosis. Disruption of cyclin A1, Cdk2, and Cdk4 expression in transgenic mice results in infertility and gonadal atrophy. Cdk,cyclin complexes interact with regulatory proteins, which may fine-tune the activities of the complex. One of the many regulatory proteins is p12, a 115 amino acid growth suppressor polypeptide designated p12CDK2AP1, partner of Cdk2 and with binding affinity to DNA polymerase ,/primase. Overexpression of p12 is associated with testicular and ovarian atrophy without affecting fertility. Ectopic expression of p12 was driven by the keratin 14 promoter. Keratin 14 is the pairing partner of keratin 5 and both keratins are expressed in testis. The efficiency of keratin promoters in driving ectopic gonadal gene expression, the association of gonadal atrophy with the ectopic expression of a Cdk2 regulatory protein and the centrosome, as a reservoir of cell-cycle regulatory proteins, open new experimental opportunities to address still lingering questions concerning cell differentiation and division during mammalian gametogenesis. Mol. Reprod. Dev. 939,942, 2006. © 2006 Wiley-Liss, Inc. [source] Isolation, propagation and characterization of primary tubule cell culture from human kidney (Methods in Renal Research)NEPHROLOGY, Issue 2 2007WEIER QI SUMMARY: Proximal tubule cells (PTC) are the major cell type in the cortical tubulointerstitium. Because PTC play a central role in tubulointerstitial pathophysiology, it is essential to prepare pure PTC from kidney tissue to explore the mechanisms of tubulointerstitial pathology. The authors have successfully refined and characterized primary cultures of human PTC using Percoll density gradient centrifugation as a key PTC enrichment step. The cells obtained by this method retain morphological and functional properties of PTC and are minimally contaminated by other renal cells. In particular, the primary isolates have characteristics of epithelial cells with uniform polarized morphology, tight junction and well-formed apical microvilli. Cytokeratin is uniformly and strongly expressed in the isolates. Brush border enzyme activities and PTC transport properties are retained in the isolates. This method therefore provides an excellent in vitro model for the physiologic study of the human proximal tubule. [source] Bone mineral density and urinary N -acetyl-,- d -glucosaminidase activity in paediatric patients with idiopathic hypercalciuriaNEPHROLOGY, Issue 2 2005SYLVA SKALOVA SUMMARY: Background: Idiopathic hypercalciuria (IH) is defined as hypercalciuria that persists after correction of dietary inbalances and has no detectable causes. Patients with IH have a higher prevalence of osteoporosis. Defective reabsorption of calcium by the renal tubule is considered a likely mechanism of IH. N -acetyl-beta- d -glucosaminidase (NAG) is a lysosomal enzyme that is a very sensitive marker of renal tubular impairment. Methods: Fifteen patients (nine boys and six girls, mean age 12.4 ± 4.0 years) with IH (urinary calcium excretion >0.1 mmol/kg per 24 h) had their bodyweight, height, body mass index (BMI), urinary NAG/creatinine ratio (U-NAG/Cr) and 24-h urinary calcium excretion (U-Ca/24 h) assessed. L1,L4 bone mineral density (BMD) was measured by dual energy X-ray absorptiometry and volumetric BMD (BMDvol) was calculated. The obtained results were expressed as Z-scores. Results: The values of basic anthropometric parameters did not differ significantly from the values of the reference population and there was a tendency to short stature, which did not reach statistical significance (P = 0.08). The values of calciuria and U-NAG/Cr were significantly higher while BMD was significantly lower when compared to the reference values (P < 0.0006, P < 0.006 and P < 0.001, respectively). Inverse and significant correlations were found between U-Ca/24 h and ,BMD, U-Ca/24 h and body height, and U-Ca/24 h and BMDvol (r = ,0.64 and ,0.70, respectively, P < 0.01; r = ,0.55, P < 0.05), while there was no correlation between U-NAG/Cr and U-Ca/24 h, nor between BMD and weight or BMD and BMI. Conclusion: Tubular impairment is highly probable in children with IH, but there is a poor relationship with the degree of calcium leakage. Idiopathic hypercalciuria should be considered as a risk factor for stunted growth and low bone mass. [source] Low-grade renal cell carcinoma arising from the lower nephron: A case report with immunohistochemical, histochemical and ultrastructural studiesPATHOLOGY INTERNATIONAL, Issue 12 2001Masako Otani Most renal cell carcinomas (RCC) are composed of clear cells with sinusoid-like vasculatures and originate from the proximal tubule. On the other hand, collecting duct carcinoma (CDC) and chromophobe RCC are thought to originate from the lower nephron. In the present study, we present a case of unusual RCC. The patient was a 68-year-old Japanese woman who had developed general fatigue with hematuria. Computed tomography revealed a left renal tumor suggesting sarcoma. The resected tumor was located in the renal parenchyma, measuring 12 × 10 × 8 cm in size. Histologically, the tumor consisted principally of cuboidal cells forming parallel or radiating arrays, continuous with the spindle-shaped cells. Most parts of the tumor showed hemorrhagic necrosis. Immunohistochemically, tumor cells were positive for high molecular weight cytokeratins, vinculin, vimentin, CD15 and epithelial membrane antigen, and showed affinities with some kinds of lectins. N- and E-cadherins and , -catenin were diffusely positive in tumor cells. Nuclear positivity for Ki-67 and p53 protein were approximately 2.0 and 1.7%, respectively. Considering its morphological and histochemical natures, this tumor is considered to have originated from the lower nephron, which is unique for a tumor of low-grade malignancy. [source] Murine glutathione S -transferase A1-1 in sickle transgenic miceAMERICAN JOURNAL OF HEMATOLOGY, Issue 10 2007Yelena Z. Ginzburg Patients with sickle cell anemia exhibit mild to moderate renal and liver damage. Glutathione S -transferase A1-1 is produced during kidney and liver damage. We hypothesized that cellular damage in sickle transgenic mice would lead to increased serum and urine murine glutathione S -transferase A1-1 levels. Levels of murine glutathione S -transferase A1-1 in the serum and urine of S+S-Antilles, NY1DD, and control mice were measured by ELISA, which revealed that the serum of S+S-Antilles mice, relative to controls, had elevated levels of murine glutathione S -transferase A1-1 (P = 0.005) as did NY1DD mice (P = 0.02, baseline vs. 2-day hypoxia). Serum liver enzymes, such as aspartate amino transferase and alanine amino transferase, as well as lactate dehydrogenase were increased in S+S-Antilles mice relative to controls (P = 0.000006, P = 0.0003, and P = 0.029, respectively). Urine murine glutathione S -transferase A1-1 of S+S-Antilles mice, as well as NY1DD mice under hypoxic stress, was not significantly different from controls. Murine glutathione S -transferase class-mu was measured by ELISA in the urine of sickle transgenic mice and control mice to define the location of tubular damage at the proximal convoluted tubule; murine Glutathione S -transferase class-mu was below the limit of detection. These findings suggest that elevated levels of murine glutathione S -transferase A1-1 in the serum reflect release during liver damage and that proximal tubular damage does not lead to appreciable urinary murine glutathione S -transferase A1-1. Am. J. Hematol. 82:911,915, 2007. © 2007 Wiley-Liss, Inc. [source] Proteomic analysis of human proximal tubular cells exposed to high glucose concentrationsPROTEOMICS - CLINICAL APPLICATIONS, Issue 7-8 2008Eun-Jeong So Abstract Hyperglycemia is a major key factor in the pathogenesis of microvascular complications of diabetes, including diabetic nephropathy (DN). Most studies to date have focused on the glomerular abnormalities found in DN. However, nephromegaly in the early stages of diabetes and the correlation of tubulointerstitial pathology rather than glomerular pathology with declining renal function in DN suggests the involvement of the tubulointerstitium. The etiology of the tubulointerstitial pathology in DN, however, is not fully understood. In this study, to understand the DN pathways, we constructed an initial 2-DE reference map for primitively cultured human proximal tubule (HK-2) cell in the presence of 5,mM and 25,mM glucose, which correspond to blood glucose concentrations during the normal and hyperglycemia conditions, respectively. Differentially expressed HK-2 cell cellular proteins at the high glucose concentration were identified via ESI-Q-TOF MS/MS and confirmed by Western blotting; enolase 1 (up-regulated) and lactate dehydrogenase (down-regulated). The regulation of these proteins will help in understanding DN mechanism through the glycolysis metabolic pathways in high glucose stimulated HK-2 cells. [source] A New Look on the Origin of the Gonad and the Müllerian Duct: the Sturgeon (Acipencer) as a Model for Vertebrate Urogenital DevelopmentANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005K. -H. The origin of the vertebrate gonad and the Müllerian duct are still a matter of debate. According to the majority of recent textbooks, the gonad is a product of the proliferating coelothelium and therefore derived from the mesoderm of the lateral plate region. The Müllerian duct grows parallel to the Wolffian duct, but it is not clear to what extent the latter contributes actively to the development of the former. In the last decade, we reinvestigated early gonadogenesis and Müllerian duct development in a number of vertebrate model species using various morphological techniques (TEM, SEM, immunohistochemistry). The conclusion of our studies is that rudimentary or regressing nephrostomial tubules, particularly cells of their nephrostomes, must be regarded as the immediate precursors of the somatic cells of the gonadal crest and the Müllerian infundibular field. According to this concept, both structures are derivatives of the intermediate mesoderm. Nephrostomial tubules are regular components of the primitive pro- and mesonephros. They connect the nephric tubule or the nephric corpuscle to the coelomic cavity and open into the latter by means of a funnel-like mouth, the nephrostome (coelomostome). In the larval sterlet, Acipenser ruthenus, short, segmentally arranged nephrostomial tubules with well-developed nephrostomes are present in the region of the cranial opisthonephros. Cells of the medial nephrostomial lips proliferate, surround the germ cells that have accumulated in this location and form a continuous gonadal crest. Cells of the lateral nephrostomial lips proliferate also, spread out on the coelomic surface, replace the original flat mesothelial cells over the Wolffian duct and the cranial opisthonephros and form the Müllerian infundibular field. At about 28 days, a flat pocket begins to invaginate the infundibular field. This pocket is the primordium of the Müllerian ostium abdominale. The findings in Acipenser can be generalized and transferred to other vertebrates. [source] Effect of chronic oestrogen administration on androgen receptor expression in reproductive organs and pituitary of adult male ratANDROLOGIA, Issue 3 2010M. C. Kaushik Summary Following chronic (15 or 30 days) treatment with oestradiol 3-benzoate (75 ,g rat,1 day,1 in 100 ,l of olive oil) to adult rats, androgen receptor (AR) expression was analysed simultaneously in testis, epididymis, seminal vesicle, prostate and pituitary utilising three independent tools i.e. immunohistochemistry, Western blotting and RT-PCR. All the five organs showed higher AR transcriptional activity gradually increasing from 15 to 30 days of oestrogen treatment. However, the AR protein expression either through immunostaining or Western blotting demonstrated a significant decline in all the reproductive organs. In the pituitary, on the other hand, the decline coincided with a distinct breakdown of the AR protein into two bands with increasing duration of treatment. Serum and intra-testicular testosterone levels were found significantly lowered. Spermatogenesis was adversely affected with concurrent decrease in weights of testis and accessory sex organs. Decrease in testis weight was consistent with the reduction in the number of maturing germ cells per tubule. Despite the decrease in weight, accessory sex organs like epididymis, seminal vesicle and prostate were completely devoid of any apoptotic cells which were characterised only in testis and pituitary. Seminiferous epithelium demonstrated a marked increase in the number of germ cells undergoing apoptosis. However, the rate of cell apoptosis was much higher in the pituitary than in the testis at the end of 30 days treatment. It is therefore concluded that degradation of AR protein expression after oestrogen treatment is probably directly linked to an increase in cell apoptosis both in testis and pituitary. [source] Obstructive infertility: changes in the histology of different regions of the epididymis and morphology of spermatozoaANDROLOGIA, Issue 4 2006P. C. Pal Summary In the present study, the effects of prolonged obstruction in different regions of the human epididymis on its histology and on the spermatozoa retained at the site of obstruction were assessed. Men who were confirmed of having obstruction of the epididymis underwent vasoepididymostomy (VEA) for surgical correction of the obstruction. At the time of surgery, fluid from the epididymal tubule above the site of obstruction was aspirated and examined for sperm profile. Epididymal tissue, collected at the site of obstruction, was processed for assessment of histological changes and also used to identify the site of obstruction. Prolonged obstruction of the epididymis has caused degeneration of the epididymal epithelium, gradual decrease in the diameter of the tubule and tubular lumen and increase in the intertubular connective tissue. Sperm aspirated from the caput epididymal fluid showed sluggish pattern of motility only in one out of the six subjects, whereas spermatozoa collected from the cauda epididymal fluid showed rapid linear progressive motility in one of three subjects. A major percentage of spermatozoa in the aspirated fluid showed various types of morphological abnormalities, irrespective of the site of obstruction. These results are discussed in relation to the role of the epididymis in investing spermatozoa with motility and fertilizing capacity. [source] | |||||||||||||||||||||||||||||||||||||||||||