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Basal Lamina (basal + lamina)
Selected AbstractsFzd3 and Fzd6 deficiency results in a severe midbrain morphogenesis defectDEVELOPMENTAL DYNAMICS, Issue 1 2010Sebastian Stuebner Abstract Wnt/,-catenin signaling controls the proper development of the mid-/hindbrain region (MHR) and of midbrain dopaminergic (mDA) neurons, but the Frizzled (Fzd) receptors transducing these signals are still unknown. Fzd3 is expressed throughout the mouse anterior neural tube, whereas Fzd6 is restricted to the MHR. We show that the MHR is properly established and mDA neurons develop normally in Fzd6,/, mutants, but the number of mDA neurons is initially reduced and recovers at later stages in Fzd3,/, embryos. Fzd3,/,; Fzd6,/, double mutants exhibit a severe midbrain morphogenesis defect consisting of collapsed brain ventricles, apparent thickening of the neuroepithelium, focal disruption of the ventricular basal lamina and protrusion of individual cells, and increased proliferation at later stages, despite a normal closure of the anterior neural tube and the rescue of the mDA defect in these embryos. Fzd3 and Fzd6 thus control proper midbrain morphogenesis by a yet unknown mechanism in the mouse. Developmental Dynamics 239:246,260, 2010. © 2009 Wiley-Liss, Inc. [source] Expression profiles of the duplicated matrix metalloproteinase-9 genes suggest their different roles in apoptosis of larval intestinal epithelial cells during Xenopus laevis metamorphosisDEVELOPMENTAL DYNAMICS, Issue 8 2007Takashi Hasebe Abstract Matrix metalloproteinases (MMPs) play a pivotal role in development and/or pathogenesis through degrading extracellular matrix (ECM) components. We have previously shown that Xenopus MMP-9 gene is duplicated. To assess possible roles of MMP-9 and MMP-9TH in X. laevis intestinal remodeling, we here analyzed their expression profiles by in situ hybridization and show that their expression is transiently up-regulated during thyroid hormone-dependent metamorphosis. Of interest, MMP-9TH mRNA is strictly localized in the connective tissue and most highly expressed just beneath the larval epithelium that begins to undergo apoptosis. On the other hand, cells expressing MMP-9 mRNA become first detectable in the connective tissue and then, after the start of epithelial apoptosis, also in the larval epithelium. These results strongly suggest that MMP-9TH is responsible in the larval epithelial apoptosis through degrading ECM components in the basal lamina, whereas MMP-9 is involved in the removal of dying epithelial cells during amphibian intestinal remodeling. Developmental Dynamics 236:2338,2345, 2007. © 2007 Wiley-Liss, Inc. [source] ROCK inhibitor (Y27632) increases apoptosis and disrupts the actin cortical mat in embryonic avian corneal epitheliumDEVELOPMENTAL DYNAMICS, Issue 3 2004Kathy K.H. Svoboda Abstract The embryonic chicken corneal epithelium is a unique tissue that has been used as an in vitro epithelial sheet organ culture model for over 30 years (Hay and Revel [1969] Fine structure of the developing Avian cornea. Basel, Switzerland: S. Karger A.G.). This tissue was used to establish that epithelial cells could produce extracellular matrix (ECM) proteins such as collagen and proteoglycans (Dodson and Hay [1971] Exp Cell Res 65:215,220; Meier and Hay [1973] Dev Biol 35:318,331; Linsenmayer et al. [1977] Proc Natl Acad Sci U S A 74:39,43; Hendrix et al. [1982] Invest Ophthalmol Vis Sci 22:359,375). This historic model was also used to establish that ECM proteins could stimulate actin reorganization and increase collagen synthesis (Sugrue and Hay [1981] J Cell Biol 91:45,54; Sugrue and Hay [1982] Dev Biol 92:97,106; Sugrue and Hay [1986] J Cell Biol 102:1907,1916). Our laboratory has used the model to establish the signal transduction pathways involved in ECM-stimulated actin reorganization (Svoboda et al. [1999] Anat Rec 254:348,359; Chu et al. [2000] Invest Ophthalmol Vis Sci 41:3374,3382; Reenstra et al. [2002] Invest Ophthalmol Vis Sci 43:3181,3189). The goal of the current study was to investigate the role of ECM in epithelial cell survival and the role of Rho-associated kinase (p160 ROCK, ROCK-1, ROCK-2, referred to as ROCK), in ECM and lysophosphatidic acid (LPA) -mediated actin reorganization. Whole sheets of avian embryonic corneal epithelium were cultured in the presence of the ROCK inhibitor, Y27632 at 0, 0.03, 0.3, 3, or 10 ,M before stimulating the cells with either collagen (COL) or LPA. Apoptosis was assessed by Caspase-3 activity assays and visualized with annexin V binding. The ROCK inhibitor blocked actin cortical mat reformation and disrupted the basal cell lateral membranes in a dose-dependent manner and increased the apoptosis marker annexin V. In addition, an in vitro caspase-3 activity assay was used to determine that caspase-3 activity was higher in epithelia treated with 10 ,M Y-27632 than in those isolated without the basal lamina or epithelia stimulated with fibronectin, COL, or LPA. In conclusion, ECM molecules decreased apoptosis markers and inhibiting the ROCK pathway blocked ECM stimulated actin cortical mat reformation and increased apoptosis in embryonic corneal epithelial cells. Developmental Dynamics 229:579,590, 2004. © 2004 Wiley-Liss, Inc. [source] Chronological gene expression of ADAMs during testicular development: Prespermatogonia (gonocytes) express fertilin , (ADAM2)DEVELOPMENTAL DYNAMICS, Issue 3 2003Carolina Rosselot Abstract Immediately after birth, primordial germinal cell-derived prespermatogonia (PSG), located in the center of the testicular cords, migrate between adjacent Sertoli cells to establish contact with the cord basal lamina. PSG migration suggests continued assembly and disassembly of cell,cell contacts by a molecular mechanism that may involve integrins and their ligands, the disintegrin domain of spermatogenic cell-specific plasma membrane proteins called ADAMs. We have analyzed the temporal gene expression of selected ADAMs in intact fetal, early postnatal, and pubertal rat testis and Sertoli,spermatogenic cell cocultures by reverse transcriptase-polymerase chain reaction, in situ hybridization, and immunocytochemistry. We report that several ADAM transcripts are expressed in fetal, neonatal, and prepubertal testes. Cyritestin (ADAM3), ADAM5, ADAM6, and ADAM15 are expressed in day 17 fetal testes. In contrast, no expression of fertilin , (ADAM1) and fertilin , (ADAM 2) was detected in fetal testes. Fertilin , gene expression starts after postnatal day 2, subsequent to the expression of fertilin ,, which occurs on postnatal day 1. After postnatal day 2, all the indicated ADAMs, including the fertilin , and fertilin ,, continue to be expressed. Transcripts of spermatogenic cell-specific fertilin ,, fertilin ,, ADAM3, and ADAM5 were detected during the coculture of PSG with Sertoli cells for up to 72 hr after plating. The presence of fertilin , mRNA and protein in cocultured PSG was visualized by in situ hybridization and immunocytochemistry, respectively. These observations indicate that PSG in coculture with Sertoli cells provide a suitable approach for analyzing cell,cell adhesive responses involving spermatogenic cell-specific ADAMs. Development Dynamics 458,467, 2003. © 2003 Wiley-Liss, Inc. [source] Spatiotemporal distribution of heparan sulfate epitopes during myogenesis and synaptogenesis: A study in developing mouse intercostal muscleDEVELOPMENTAL DYNAMICS, Issue 1 2002Guido J. Jenniskens Abstract Formation of a basal lamina (BL) ensheathing developing skeletal muscle cells is one of the earliest events in mammalian skeletal muscle myogenesis. BL-resident heparan sulfate proteoglycans have been implicated in various processes during myogenesis, including synaptic differentiation. However, attention has focused on the proteoglycan protein core, ignoring the glycosaminoglycan moiety mainly because of a lack of appropriate tools. Recently, we selected a panel of anti,heparan sulfate antibodies applied here to study the spatiotemporal distribution of specific heparan sulfate (HS) epitopes during myogenesis. In mouse intercostal muscle at embryonic day (E14), formation of acetylcholine receptor clusters at synaptic sites coincides with HS deposition. Although some HS epitopes show a general appearance throughout the BL, one epitope preferably clusters at synaptic sites but does so only from E16 onward. During elongation and maturation of primary myotubes, a process preceding secondary myotube development, significant changes in the HS epitope constitution of both synaptic and extrasynaptic BL were observed. As a whole, the data presented here strengthen previous observations on developmental regulation by BL components, and add to the putative roles of specific HS epitopes in myogenesis and synaptogenesis. © 2002 Wiley-Liss, Inc. [source] Histopathological alterations in the edible snail, Babylonia areolata (spotted babylon), in acute and subchronic cadmium poisoningENVIRONMENTAL TOXICOLOGY, Issue 2 2005P. Tanhan Abstract Histopathological alterations in 6- to 8-month-old juvenile spotted babylon, Babylonia areolata, from acute and subchronic cadmium exposure were studied by light microscopy. The 96-h LC50 value of cadmium for B. areolata was found to be 3.35 mg/L, and the maximum acceptable toxicant concentration (MATC) was 1.6 mg/L. Snails were exposed to 3.35 and 0.08 mg/L (5% of MATC) of cadmium for 96 h and 90 days, respectively. After exposure the gill, the organs of the digestive system (proboscis, esophagus, stomach, digestive gland, and rectum), and the foot were analyzed for cadmium accumulation. The results showed that most digestive organs had a high affinity for cadmium. The main target organ was the stomach, which could accumulate on average 1192.18 ,g/g dry weight of cadmium. Cadmium was shown to accumulate to a lesser extent in the digestive gland, gill, rectum, esophagus, proboscis, and foot. Histopathological alterations were observed in the gill and digestive organs (proboscis, esophagus, stomach, and rectum). The study showed that the stomach and gill were the primary target organs of both acute and subchronic exposure. Gill alterations included increased size of mucous vacuoles, reduced length of cilia, dilation and pyknosis of nuclei, thickening of basal lamina, and accumulation of hemocytes. The epithelial lining of the digestive tract showed similar alterations such as increased size of mucous vacuoles, reduced length of cilia, and dilation of nuclei. In addition, fragmentation of the muscle sheath was observed. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 142,149, 2005. [source] Chlamydiae and polymorphonuclear leukocytes: unlikely allies in the spread of chlamydial infectionFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1 2008Roger G. Rank Abstract While much is known about the attachment of the chlamydiae to the host cell and intracellular events during the developmental cycle, little is known about the mechanism(s) by which elementary bodies exit the cell. In this report, we use the guinea-pig conjunctival model of Chlamydia caviae infection to present in vivo ultrastructural evidence supporting two mechanisms for release of chlamydiae from the mucosal epithelia. Four days after infection, histopathologic observation shows an intense infiltration of polymorphonuclear leukocytes (PMN) in the conjunctival epithelium. Using transmission electron microscopy, a gradient-directed PMN response to chlamydiae-infected epithelial cells was observed. As PMN infiltration intensifies, epithelial hemidesmosome/integrin/focal adhesion adherence with the basal lamina is disconnected and PMNs literally lift off and release infected superficial epithelia from the mucosa. Many of these infected cells appear to be healthy with intact microvilli, nuclei, and mitochondria. While lysis of some infected cells occurs with release of chlamydiae into the extracellular surface milieu, the majority of infected cells are pushed off the epithelium. We propose that PMNs play an active role in detaching infected cells from the epithelium and that these infected cells eventually die releasing organisms but, in the process, move to new tissue sites via fluid dynamics. [source] Nucleotide-induced Ca2+ signaling in sustentacular supporting cells of the olfactory epitheliumGLIA, Issue 15 2008Thomas Hassenklöver Abstract Extracellular purines and pyrimidines are important signaling molecules acting via purinergic cell-surface receptors in neurons, glia, and glia-like cells such as sustentacular supporting cells (SCs) of the olfactory epithelium (OE). Here, we thoroughly characterize ATP-induced responses in SCs of the OE using functional Ca2+ imaging. The initial ATP-induced increase of the intracellular Ca2+ concentration [Ca2+]i always occurred in the apical part of SCs and subsequently propagated toward the basal lamina, indicating the occurrence of purinergic receptors in the apical part of SCs. The mean propagation velocity of the Ca2+ signal within SCs was 17.10 ± 1.02 ,m/s. ATP evoked increases in [Ca2+]i in both the presence and absence of extracellular Ca2+. Depletion of the intracellular Ca2+ stores abolished the responses. This shows that the ATP-induced [Ca2+]i increases were in large part, if not entirely, due to the activation of G protein-coupled receptors followed by Ca2+ mobilization from intracellular stores, suggesting an involvement of P2Y receptors. The order of potency of the applied purinergic agonists was UTP > ATP > ATP,S (with all others being only weakly active or inactive). The ATP-induced [Ca2+]i increases could be reduced by the purinergic antagonists PPADS and RB2, but not by suramin. Our findings suggest that extracellular nucleotides in the OE activate SCs via P2Y2/P2Y4 -like receptors and initiate a characteristic intraepithelial Ca2+ wave. © 2008 Wiley-Liss, Inc. [source] Schwann cell myelination occurred without basal lamina formation in laminin ,2 chain-null mutant (dy3K/dy3K) miceGLIA, Issue 2 2001Masahiro Nakagawa Abstract The laminin ,2 chain is a major component of basal lamina in both skeletal muscle and the peripheral nervous system. Laminin ,2 chain deficiency causes merosin-deficient congenital muscular dystrophy, which affects not only skeletal muscles, but also the peripheral and central nervous systems. It has been reported that the formation of basal lamina is required for myelination in the peripheral nervous system. In fact, the spinal root of dystrophic mice (dy/dy mice), whose laminin ,2 chain expression is greatly reduced, shows lack of basal lamina and clusters of naked axons. To investigate the role of laminin ,2 chain and basal lamina in vivo, we examined the peripheral nervous system of dy3K/dy3Kmice, which are null mutants of laminin ,2 chain. The results indicate the presence of myelination although Schwann cells lacked basal lamina in the spinal roots of dy3K/dy3K mice, suggesting that basal lamina is not an absolute requirement for myelination in vivo. Immunohistochemically, the expression of laminin ,4 chain was increased and laminin ,5 chain was preserved in the endoneurium of the spinal root. Laminin ,4 and ,5 chains may play the critical role in myelination instead of laminin ,2 chain in dy3K/dy3Kmice. In addition, the motor conduction velocity of the sciatic nerve was significantly reduced compared with that of wild-type littermate. This reduction in conduction velocity may be due to small axon diameter, thin myelin sheath and the patchy disruption of the basal lamina of the nodes of Ranvier in dy3K/dy3Kmice. GLIA 35:101,110, 2001. © 2001 Wiley-Liss, Inc. [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] A Japanese case of Kindler syndromeINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 4 2000Yasushi Suga MD A 25-year-old Japanese woman presented with contracture of the fingers and toes, and difficulty in opening her mouth. Her grandparents are first cousins, but none of the other members of the family are affected. Bulla formation started at birth on areas of the skin that received pressure, and in infancy and early childhood the lesions were limited only to the acral areas. She also had bilateral, incomplete syndactylies involving all web spaces ( Fig. 1a). The formation of blisters ceased after the age of 15 years, but a generalized progressive poikiloderma then appeared with accompanying cutaneous atrophy of the skin of the neck, trunk, and extremities ( Fig. 1b). The patient experienced mild photosensitivity of the face and neck. At age 18 years, surgical removal of the webbing of all her fingers was performed. Oral examination showed atrophy of the buccal mucosa, and an inability to fully open the mouth. The patient also suffered from poor dentition and easily bleeding gums, but had no symptoms of esophageal dysfunction. Figure 1. Clinical manifestations of the patient with Kindler syndrome. (a) Dorsal surface of the patient's hands. Note the marked cutaneous atrophy with a severely wrinkled appearance on the dorsal surface of the hands, as well as the proximal fusion of the fingers. (b) Lower left leg of the patient. Atrophic thinning of the skin and poikiloderma with reticular pigmentation are evident Histology of separate biopsy specimens, taken from the poikilodermatous pretibial and trunk skin, showed classical features of poikiloderma, namely epidermal atrophy with flattening of the rete ridges, vacuolization of basal keratinocytes, pigmentary incontinence, and mild dermal perivascularization ( Fig. 2a). Interestingly, dyskeratotic cells ( Fig. 2b) and eosinophilic rounded bodies (colloid bodies) ( Fig. 2c) were frequently found at the basal keratinocyte layer and in the upper dermis, respectively. Pigment was also present in the upper epidermis. Figure 2. Hematoxylin and eosin staining of a biopsy specimen taken from pretibial skin. (a) Epidermal atrophy with flattening of the rete ridges. Note the dyskeratotic cells (arrowheads) and vacuolar degeneration of the basal layer in the epidermis. Bar = 50 ,m. (b) Higher magnification of dyskeratotic cells (arrowheads). Bar = 10 ,m. (c) Higher magnification of colloid bodies (arrowheads) in the superficial dermis. Bar = 10 ,m To rule out the possibility of a congenital epidermolysis bullosa, ultrastructural and immunofluorescence studies were performed. Ultrastructural studies demonstrated the reduplication of the basal lamina with branching structures within the upper dermis and cleavage between the lamina densa and the cell membrane of the keratinocytes ( Fig. 3a). The numbers of associated anchoring fibrils did not seem to be reduced, and colloid bodies and dyskeratotic cells were detected. Immunofluorescence studies with the antibody against type VII collagen (LH 7 : 2) were subsequently carried out. The results showed extensive broad bands with intermittently discontinuous and reticular staining at the dermo-epidermal junction (DEJ) ( Fig. 3b), whereas a linear distribution is typically seen in healthy tissue (data not shown). Interestingly, direct immunofluorescence studies revealed intracellular accumulation of immunoglobulin G (IgG), IgM, IgA, and C3 in colloid bodies under the basement membrane ( Fig. 3c). Figure 3. Ultrastructural and immunohistochemical findings of the patient with Kindler syndrome. (a) Ultrastructural study of the dermo-epidermal junction. The branching structures of the lamina densa (arrowheads) were frequently seen. The asterisks show the cleavage in the lamina lucida. Bar = 1 ,m. (b) Immunohistochemical studies with the antibody to type VII collagen (LH 7 : 2). An extensive broad band with reticular patterns is evident. Bar = 50 ,m. E, epidermis; D, dermis. (c) Direct immunofluorescence study. Intracytoplasmic deposition of IgM in the basal keratinocytes is evident (arrowheads). Bar = 50 ,m. E, epidermis; D, dermis [source] Embryo development of Corticium candelabrum (Demospongiae: Homosclerophorida)INVERTEBRATE BIOLOGY, Issue 3 2007Sonia De Caralt Abstract. Corticium candelabrum is a homosclerophorid sponge widespread along the rocky Mediterranean sublittoral. Scanning and transmission electron microscopy were used to describe the gametes and larval development. The species is hermaphroditic. Oocytes and spermatocytes are clearly differentiated in April. Embryos develop from June to July when the larvae are released spontaneously. Spermatic cysts originate from choanocyte chambers and spermatogonia from choanocytes by choanocyte mitosis. Oocytes have a nucleolate nucleus and a cytoplasm filled with yolk granules and some lipids. Embryos are surrounded by firmly interlaced follicular cells from the parental tissue. A thin collagen layer lies below the follicular cells. The blastocoel is formed by migration of blastomeres to the morula periphery. Collagen is spread through the whole blastocoel in the embryo, but is organized in a dense layer (basal lamina) separating cells from the blastocoel in the larva. The larva is a typical cinctoblastula. The pseudostratified larval epithelium is formed by ciliated cells. The basal zone of the ciliated cells contains lipid inclusions and some yolk granules; the intermediate zone is occupied by the nucleus; and the apical zone contains abundant electron-lucent vesicles and gives rise to cilia with a single cross-striated rootlet. Numerous paracrystalline structures are contained in vacuoles within both apical and basal zones of the ciliated cells. Several slightly differentiated cell types are present in different parts of the larva. Most cells are ciliated, and show ultrastructural particularities depending on their location in the larvae (antero-lateral, intermediate, and posterior regions). A few smaller cells are non-ciliated. Several features of the C. candelabrum larva seem to support the previously proposed paraphyletic position of homoscleromorphs with respect to the other demosponges. [source] Developmental changes in the ultrastructure of the lamprey lateral line nerve during metamorphosisJOURNAL OF MORPHOLOGY, Issue 7 2009S. Gelman Abstract The ultrastructure of the trunk lateral line nerve of larval and adult lampreys was studied with transmission electron microscopy. We confirmed that lampreys' lateral line nerve lacks myelin. Nevertheless, all axons were wrapped by Schwann cell processes. In the larval nerve, gaps between Schwann cells were observed, where the axolemma was covered only by a basal lamina, indicating an earlier developmental stage. In the adult nerve, glial (Schwann cell) ensheathment was mostly complete. Additionally, we observed variable ratios of axons to Schwann cells in larval and adult preparations. In the larval nerve, smaller axons were wrapped by one Schwann cell. Occasionally, a single Schwann cell surrounded two axons. Larger axons were associated with two to five Schwann cells. In the adult nerve, smaller axons were surrounded by one, but larger axons by three to eight Schwann cells. The larval epineurium contained large adipose cells, separated from each other by single fibroblast processes. This layer of adipose tissue was reduced in adult preparation. The larval perineurium was thin, and the fibroblasts, containing large amounts of glycogen granules, were arranged loosely. The adult perineurium was thicker, consisting of at least three layers of fibroblasts separated by collagen fibrils. The larval and adult endoneurium contained collagen fibrils oriented orthogonally to each other. Both larval and adult lateral line nerves possessed a number of putative fascicles weakly defined by a thin layer of perineurial fibroblasts. These results indicate that after a prolonged larval stage, the lamprey lateral line nerve is subjected to additional maturation processes during metamorphosis. J. Morphol. 2009. © 2009 Wiley-Liss, Inc. [source] Gut-associated cells of derocheilocaris remanei (crustacea, mystacocarida)JOURNAL OF MORPHOLOGY, Issue 3 2002Isabel Fernández Abstract The gut-associated cells (GA-cells) of the mystacocarid Derocheilocaris remanei were investigated by transmission electron microscopy. These cells are characterized by a dense cytoplasm, the presence of clear vesicles adjacent to the gut epithelium, glycogen, and lipid droplets. GA-cells envelop the midgut and hindgut and send blunt cytoplasmic extensions to the gut epithelium through its basal lamina. The GA-cells also extend dorsolateral projections to the body wall by means of intermediate cells. In addition to a mechanical function of suspending and stabilizing the gut, these cells may affect the flow of the hemocoelic fluid and may be implicated in the processes of transport, assimilation, and storage of nutrients. J. Morphol. 251:276,283, 2002. © 2002 Wiley-Liss, Inc. [source] Ultrastructural study of the precursor to fungiform papillae prior to the arrival of sensory nerves in the fetal ratJOURNAL OF MORPHOLOGY, Issue 3 2001Shin-ichi Iwasaki Abstract The structure of precursors to fungiform papillae without taste buds, prior to the arrival of sensory nerve fibers at the papillae, was examined in the fetal rat on embryonic day 13 (E13) and 16 (E16) by light and transmission electron microscopy in an attempt to clarify the mechanism of morphogenesis of these papillae. At E13, a row of rudiments of fungiform papillae was arranged along both sides of the median sulcus of the lingual dorsal surface, and each row consisted of about 10 rudiments. There was no apparent direct contact between papillae rudiments and sensory nerves at this time. Bilaterally towards the lateral side of the tongue, adjacent to these first rudiments of fungiform papillae, a series of cord-like invaginations of the dorsal epithelium of the tongue into the underlying connective tissue, representing additional papillary primordia parallel to the first row, was observed. The basal end of each invagination was enlarged as a round bulge, indented at its tip by a mound of fibroblasts protruding into the bulge. At E16 there was still no apparent direct contact between rudiments of fungiform papillae and sensory nerves. Each rudiment apically contained a spherical core of aggregating cells, which consisted of a dense assembly of large, oval cells unlike those in other areas of the lingual dorsal epithelium. The differentiation of these aggregated cells was unclear. The basal lamina was clearly recognizable between the epithelium of the rudiment of fungiform papillae and the underlying connective tissue. Spherical structures, which appeared to be sections of the cord-like invaginations of the lingual epithelium that appeared on E13, were observed within the connective tissue separated from the dorsal lingual epithelium. Transverse sections of such structures revealed four concentric layers of cells: a central core, an inner shell, an outer shell, and a layer of large cells. Bundles of fibers were arranged in the central core, and the diameters of bundles varied somewhat depending on the depth of the primordia within the connective tissue and their distance from the median sulcus. Ultrastructural features of cells in the outer shell differed significantly in rudiments close to the lingual epithelium as compared to those in deeper areas of connective tissue. Around the outer shell there was a large-cell layer consisting of one to three layers of radially elongated, oval cells that contained many variously sized, electron-dense, round granules. Large numbers of fibroblasts formed dense aggregates around each spherical rudiment, and were separated by the basal lamina from the large-cell epithelial layer. Progressing from deep-lying levels of the rudiments of the papillae to levels close to the lingual surface epithelium, the central core, inner shell, and outer shell gradually disappeared from the invaginated papillary cords. J. Morphol. 250:225,235, 2001. © 2001 Wiley-Liss, Inc. [source] Morphological Evidence for Direct Interaction Between Gonadotrophin-Releasing Hormone Neurones and Astroglial Cells in the Human HypothalamusJOURNAL OF NEUROENDOCRINOLOGY, Issue 9 2007M. Baroncini In rodents, there is compelling evidence indicating that dynamic cell-to-cell communications involving cross talk between astroglial cells (such as astrocytes and specialised ependymoglial cells known as tanycytes) and neurones are important in regulating the secretion of gonadotrophin-releasing hormone (GnRH), the neurohormone that controls both sexual maturation and adult reproductive function. However, whether such astroglial cell,GnRH neurone interactions occur in the human brain is not known. In the present study, we used immunofluorescence to examine the anatomical relationship between GnRH neurones and glial cells within the hypothalamus of five women. Double-staining experiments demonstrated the ensheathment of GnRH neurone perikarya by glial fibrillary acidic protein (GFAP)-immunoreactive astrocyte processes in the periventricular zone of the tuberal region of the hypothalamus. GFAP immunoreactivity did not overlap that of GnRH at the GnRH neurone's projection site (i.e. the median eminence of the hypothalamus). Rather, human GnRH neuroendocrine fibres were found to be closely associated with vimentin or nestin-immunopositive radial gial processes likely belonging to tanycytes. In line with these light microscopy data, ultrastructural examination of GnRH-immunoreactive neurones showed numerous glial cells in direct apposition to pre-embedding-labelled GnRH cell bodies and/or dendrites in the infundibular nucleus, whereas postembedding immunogold-labelled GnRH nerve terminals were often seen to be enwrapped by glial cell processes in the median eminence. GnRH nerve button were sometimes visualised in close proximity to fenestrated pituitary portal blood capillaries and/or evaginations of the basal lamina that delineate the pericapillary space. In summary, these data demonstrate that GnRH neurones morphologically interact with astrocytes and tanycytes in the human brain and provide evidence that glial cells may contribute physiologically to the process by which the neuroendocrine brain controls the function of GnRH neurones in humans. [source] Malignant peripheral nerve sheath tumor of the uterine cervix expressing both S-100 protein and HMB-45JOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 6 2009Na Rae Kim Abstract A 50-year-old woman presented with a large cervical polypoid mass. Grossly, the mass occupied a substantial proportion of the cervical canal, measuring 6 cm. Histologically, the mass showed a spindle cell malignancy arranged in large fascicles that penetrated deeply into the fibromuscular wall of the cervix. The spindle cells were immunoreactive for both S-100 protein and HMB-45 antigen, but were negative for Melan-A. Electron microscopy showed that cytoplasmic processes of the spindle to oval tumor cells contained microtubules and were lined by basal lamina and abundant intercellular collagen spacing with no melanosomes in any stage. As far as we are aware, this is the ninth reported case of cervical malignant peripheral nerve sheath tumor (MPNST), and the second reported case of MPNST expressing HMB-45 antigen. [source] Proliferation and differentation markers in snuff-induced oral mucosal lesionsJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 5 2002Marina Merne Abstract Background: Regular use of snuff is known to cause whitish oral mucosal lesions of variable severity at the usual quid placement site. The main aim of this study was to elucidate cellular mechanisms involved in snuff-induced epithelial changes. Methods: Expression patterns for markers of cell proliferation (PCNA, Ki-67), cell cycle regulation (p53, p21), keratin changes (pankeratin, CK18, CK19), cell stress (HSP 70) and collagen type IV in 14 snuff-induced oral mucosal lesions and 12 control samples were analyzed by immunohistochemistry (IHC). Results: On light microscopy, all snuff-induced lesions were characterized by a hyperkeratinized and thickened epithelium. Some vacuolized cells, markers of cell degeneration, were frequently seen (in 9/14 of the samples) in the superficial layers in epithelia. Expression of PCNA and Ki-67 was found in a statistically significantly fewer cells in snuff-induced lesions (P < 0.001) than in the controls. This indicates that epithelia in snuff-induced lesions are not thickened as a result of increased cellular proliferation, but by protracted turnover of differentiating cells. Of cell cycle markers, p21 was found be up-regulated in 4/14 snuff-induced lesions, probably by p53-independent pathways. Only two snuff-induced lesions showed p53 positivity. However, the number of stained cells with p53 and p21 was not statistically different from that in controls. Expression of CK18, but not any alterations in CK19 expression, was seen in 5 of 14 snuff-induced lesions. Snuff also seems to stimulate the expression of collagen type IV, possibly by basal cells, as indicated by the thickened staining of the basal lamina. Conclusions: The findings of this study showing suppressed cellular proliferation and infrequent p53 dysfunction in snuff lesions may partly explain why dysplastic changes are seldom seen in mucosal lesions induced by the Scandinavian type of snuff. [source] Involvement of laminin and integrins in adhesion and migration of junctional epithelium cellsJOURNAL OF PERIODONTAL RESEARCH, Issue 1 2009T. Kinumatsu Background and Objective:, The junctional epithelium attaches to the enamel surface with hemidesmosomes (of which laminin-5 and integrin-,6,4 are the main components) in the internal basal lamina. Laminin-5 is also involved in cell motility with integrin-,3,1, although their functions have not yet been clarified. The purpose of this study was to determine the functions of those adhesive components between the tooth and the junctional epithelium during cell migration. Because an idea has been proposed that directly attached to tooth cells (DAT cells) may not contribute to cell migration, 5-bromo-2-deoxyuridine staining was performed to confirm cell migration. Material and Methods:, We investigated laminin-,2 (contained only in laminin-5), integrin-,4 (involved in cell,extracellular matrix contact) and integrin-,3 (inducing cell migration) in the junctional epithelium, oral gingival epithelium and gingival sulcus epithelium of 6-wk-old ICR mice using laser microdissection, quantitative real-time reverse transcription-polymerase chain reaction, immunofluorescence and 5-bromo-2-deoxyuridine staining. Results:, Laminin and integrins were clearly immunolocalized in the basal lamina of all epithelium. Quantitative analysis of laminin and integrin mRNAs by laser microdissection showed that they were more highly expressed in DAT cells than in basal cells in the oral gingival epithelium. In particular, a 12-fold higher expression of laminin-5 was observed in the junctional epithelium compared with the oral gingival epithelium. 5-Bromo-2-deoxyuridine staining showed rapid coronal migration of DAT cells. Conclusion:, These results suggest that the abundant expression of laminin-5 and integrin-,6,4 is involved in the attachment of DAT cells to teeth by hemidesmosomes. Abundant expression of laminin-5 and integrin-,3,1 might assist in DAT cell migration, confirmed by 5-bromo-2-deoxyuridine staining during the turnover of junctional epithelium. [source] Virus-Vector Cell Interactions Regulating Transmission Specificity of Soybean Dwarf LuteovirusesJOURNAL OF PHYTOPATHOLOGY, Issue 6 2000F. E. Gildow Abstract Transmission of soybean dwarf viruses (SbDV) indigenous to Japan (SbDV-D) and to the eastern United States (SbDV-Va19) were compared in vector and nonvector aphid species. Absolute vector-specificity was maintained when Aulacorthum solani, Acyrthosiphon pisum, and Myzus persicae were allowed to feed on solutions of either virus (100 ,g/ml) through Parafil© membranes. SbDVD was transmitted only by A. solani, and SbDV-Va19 was transmitted only by A. pisum and M. persicae. Similar results were obtained when individual aphids were micro-injected with 2 ng virus and subsequently allowed to feed on healthy plants. Ultrastructural studies of A. solani and M. persicae indicated that both SbDV-D and SbDV-Va20 were acquired specifically through the aphid hindgut. No difference in hindgut acquisition specificity was observed, and both A. solani and M. persicae were able to transport SbDV-D and SbDV-Va20 into the haemocoel by endocytotic/exocytotic pathways. When injected, SbDV was shown to be associated with only the accessory salivary glands (ASG) in aphids, indicating a high level of tissue specificity. Two different interactions with the ASG were observed for SbDV-D and SbDV-Va20 in A. solani and M. persicae. SbDV-D penetrated the ASG basal lamina of A. solani, but was never observed in the basal lamina of M. persicae. The ASG basal lamina was a barrier to SbDV-D transmission by M. persicae. SbDV-Va19 penetrated the ASG basal lamina of both A. solani and M. persicae. However, SbDV-Va20 was not observed in the ASG cytoplasm in A. solani, indicating that the basal plasmalemma functioned as the transmission barrier. Observations indicated that capsid protein structure, aphid basal lamina composition and cell membrane components influenced virus-aphid interactions regulating SbDV transmission. Zusammenfassung Die Übertragung von Verzwergungsviren der Sojabohne (SbDV), die aus Japan (SbDV-D) bzw. dem Osten der USA (SbDV-Va20) stammten, wurde in Vektor und Nichtvektor-Blattlausarten geprüft. Eine absolute Vektorspezifität wurde stets festgestellt, wenn Aulacorthum solani, Acyrthosiphon pisum und Myzus persicae Lösungen mit einem der Viren (100 ,gml -1) durch Parafilm© Membranen aufnehmen konnten. SbDV-D wurde nur von A. solaniübertragen, SbDV-Va20 nur von A. pisum und M. persicae.Ähnliche Ergebnisse wurden erhalten, wenn einzelne Blattläuse Mikroinjektionen mit 2 ng Virus erhielten und anschließend an gesunden Pflanzen saugen konnten. Feinstrukturelle Untersuchungen von A. solani und M. persicae ergaben, daß SbDV-D und SbDV-Va20 spezifisch durch den Enddarm der Blattläuse aufgenommen wurden. Bei der Aufnahme durch den Enddarm wurde keine unterschiedliche Spezifität festgestellt; A. solani und M. persicae konnten SbDV-D und SbDV-Va20 durch Endo-/Exocytose in die Leibeshöhle aufnehmen. Nach Injektion wurde SbDV bei Blattläusen nur in Assoziation mit den akzessorischen Speicheldrüsen (ASG) beobachtet, was auf eine hohe Gewebsspezifität hindeutet. SbDV-D und SbDV-Va20 zeigten in A. solani und M. persicae zwei unterschiedliche Reaktionen mit den ASG. SbDV-D penetrierte die Basalmembran der ASG von A. solani, wurde in der Basalmembran von M. persicae jedoch in keinem Fall gefunden. Die Basalmembran der ASG fungierte bei M. persicae als Hindernis für eine Übertragung von SbDV-D. SbDV-Va20 penetrierte die Basalmembranen von A. solani und von M. persicae. SbDV-Va20 wurde im ASG-Cytoplasma von A. solani jedoch nicht festgestellt, was darauf hindeutet, daß das Basalplasmalemma als Übertragungshindernis fungierte. Unsere Beobachtungen zeigen, daß die Struktur des Hüllproteins, die Zusammensetzung der Basalmembranen der Blattläuse und die Zellwandbestandteile die Interaktionen zwischen Viren und Blattläusen beeinflussen, welche die SbDV-Übertragung regulieren. [source] Effects of aging and HIF-1, deficiency on permeability of hippocampal vesselsMICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2006Masaki Ueno Abstract We examined age-related changes in the blood,brain barrier (BBB) of neural cell-specific hypoxia inducible factor-1, (HIF-1,) deficient mice, which showed hydrocephalus with neuronal cell loss, to investigate an effect of neural cell-specific HIF-1, deficiency or hydrocephalus on vascular function. Vascular permeability of horseradish peroxidase (HRP) and binding of cationized ferritin (CF) particles to the endothelial cell luminal surface, as a marker of glycocalyx, were investigated. The thickness of CF-labeled glycocalyx was significantly decreased in the cortex in mutant mice compared with that of control mice, although it was not paralleled by increased vascular permeability. In addition, strong staining for HRP was seen around vessels located along the hippocampal fissure in 24-month-old mutant mice. The reaction product of HRP appeared in an increasing number of the endothelial cell abluminal vesicles and within the thickened basal lamina of arterioles in the hippocampus, showing increased vascular permeability. There were no leaky vessels in 10-week-old mutant mice or 10-week-old and 24-month-old control mice. These findings suggest the necessity of two factors, aging and hydrocephalus, for BBB dysfunction in HIF-1, deficient mice. Microsc. Res. Tech. 69:29,35, 2006. © 2006 Wiley-Liss, Inc. [source] Morphology and ultrastructure of the female accessory sex glands in various crickets (Orthoptera, Saltatoria, Gryllidae)MITTEILUNGEN AUS DEM MUSEUM FUER NATURKUNDE IN BERLIN-DEUTSCHE ENTOMOLOGISCHE ZEITSCHRIFT, Issue 2 2002Robert Sturm Abstract In the present study, the morphology and ultrastructure of the accessory sex glands in females of the three cricket species Teleogryllus commodus, Gryllus bimaculatus, and Gryllus assimilis were subject to a detailed comparison. Within the observed crickets, the pairy glands are uniformly located in the 6th and 7th abdominal segment, joining the genital chamber lateral to the terminal papilla. Each gland is composed of an apical region (R3), consisting of the end tubules which produce the main amount of secretion, a middle region (R2) storing and leading the secretion to the orifice, and a basal region (R1) defining the orifice and most basal part of the gland. Concerning the size, number of ramifications, and length/width ratio, the investigated organs are marked by great variations among the species, ranging from anisometric glands (length/width < or > 1) with low number of ramifications in Teleogryllus commodus and Gryllus assimilis to nearly isometric glands with very numerous (up to 30) ramifications in Gryllus bimaculatus. The morphology of the respective glands is uniformly expressed by an epithelium composed of a basal lamina, one layer of gland cells, and a luminal, duct-less cuticular intima forming specific spines and hair-like processes. The ultrastructure of single gland cells is marked by a basal region with a large elliptic nucleus and intracellular cisternae formed by deep invaginations of the basal cell membrane. The apical part contains numerous lipid- and protein-forming compartments, mitochondria of cristae type, vesicles, and lipid drops. The apical cell surface is enlarged by forming a dense layer of microvilli. The lipophilic secretion produced by the glands is thought to be used as a lubricant in the ovipositor during egg-laying. [source] Remodeling of extracellular matrix at ovulation of the bovine ovarian follicleMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 10 2006H.F. Irving-Rodgers Abstract Using immunohistochemistry and RNA analyses we examined the fate of components of a newly identified matrix that develops between granulosa cells (focimatrix, abbreviated from focal intraepithelial matrix) and of the follicular basal lamina in ovulating bovine ovarian follicles. Pre- and postovulatory follicles were generated by treatment with estradiol (Day 1), progesterone (Days 1,10), and prostaglandin analogue (Day 9) with either no further treatment (Group 1, n,=,6) and or with 25 mg porcine LH (Day 11, Group 2, n,=,8 or Day 10, Group 3, n,=,8) and ovariectomy on Day 12 (12,14 hr post LH in Group 2, 38,40.5 hr in Group 3). In the time frame examined no loss of follicular basal lamina laminin chains ,2 and ,1 or nidogen 1 was observed. In the follicular basal lamina collagen type IV ,1 and perlecan were present prior to ovulation; after ovulation collagen type IV ,1 was discontinuously distributed and perlecan was absent. Versican in the theca interna adjacent to the follicular basal lamina in preovulatory follicles was not observed post ovulation, however, the granulosa cells then showed strong cytoplasmic staining for versican. Expression of versican isoforms V0, V1, and V3 was detected at all stages. Focimatrix was observed in preovulatory follicles. It contained collagen type IV ,1, laminins ,2 and ,1, nidogen 1 and perlecan and underwent changes in composition similar to that of the follicular basal lamina. In conclusion focimatrix and the follicular basal lamina are degraded at ovulation. Individual components are lost at different times. Mol. Reprod. Dev. © 2006 Wiley-Liss, Inc. [source] Astroblastoma: Immunohistochemical and ultrastructural study of distinctive epithelial and probable tanycytic differentiationNEUROPATHOLOGY, Issue 1 2006Toshihiko Kubota We report the clinicopathological findings of astroblastoma found in an 8-year-old girl who was subsequently treated for 11 years. The primary superficially circumscribed tumor was located in the frontoparietal lobe, while the recurrent and the second recurrent tumor were restricted to the same region 11 years later. The tumors obtained on these three occasions showed fundamentally the same histological, immunohistochemical and fine structural features. They exhibited astrocytic as well as ependymal tanycytic features with apparent epithelial cell lineage. The tumor cells showed typical features of astroblastoma comprising prominent perivascular pseudorosettes with remarkable vascular sclerosis. The immunohistochemical study revealed intensive positivity of GFAP, vimentin, epithelial membrane antigen (EMA), cytokeratin, connexin 26 and 32, desmocollin 1 and neuronal cadherin. The fine structure revealed divergent types of junctional complexes, some of which were connected with tonofilament bundles. Numerous microvilli protruded and basal lamina abutted on the tumor cell surface. We report these unique histological features, and stress that astroblastoma should be categorized as a specific type of neuroepithelial tumor. [source] Autophagic vacuolar myopathy in twin girlsNEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 3 2006J. L. Holton Hereditary autophagic vacuolar myopathy (AVM) may occur in several diseases including the rimmed vacuolar myopathies, acid maltase deficiency, Danon disease, infantile autophagic vacuolar myopathy and X-linked myopathy with excessive autophagy (XMEA). In the latter three conditions the vacuoles are lined by membranes with sarcolemmal features. We present two unusual cases of autophagic vacuolar myopathy in twin girls born at term with no family history of neurological disease. After initial normal developmental milestones they developed progressive leg weakness and wasting with contractures from the age of 12 years. Investigations showed raised CK, normal female karyotype, normal acid maltase activity, normal nerve conduction and myopathic EMG features. Frozen sections of skeletal muscle were stained using routine tinctorial and histochemical methods. Immunohistochemical staining for spectrin, merosin, dystrophin, complement membrane attack complex and sarcoglycans was performed and ultrastructural examination undertaken. Direct sequence analysis of the lamp-2 gene using genomic DNA extracted from lymphocytes was performed. Histological analysis of the muscle biopsies demonstrated myofibres with vacuoles lacking glycogen and lipid many of which were delineated using immunohistochemistry for merosin, dystrophin and sarcoglycans. Ultrastructural examination showed duplication of the myofibre basal lamina with associated autophagic material. Vacuoles within myofibres were either membrane bound containing autophagic material or lined by plasma membrane and basal lamina. Intermyofibrillar glycogen was increased. Sequence analysis of the coding region and intron/exon boundaries of the lamp-2 gene was normal. This is the first report of female cases of AVM with sarcolemmal features. We suggest that these patients may represent manifesting carriers of XMEA, or alternatively, a new form of disease with a similar phenotype having autosomal recessive inheritance. [source] Third ventricular chordoid glioma: clinicopathological study of two cases with evidence for a poor clinical outcome despite low grade histological featuresNEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 4 2005K. M. Kurian Chordoid glioma of the third ventricle is a rare glial tumour whose precise histogenesis remains uncertain. We describe two cases that presented recently to our department and review the background literature. The neoplasm tends to occur in women and its clinical presentation is variable, resulting from acute hydrocephalus or impingement upon local structures. However, the radiological appearance is distinct, with an ovoid shape, hyperdensity and uniform contrast enhancement on computerized tomography and magnetic resonance imaging. Intraoperative smear diagnosis is difficult because of the lack of specific features, although the presence of metachromatic extracellular mucin may be useful. The characteristic histological appearance is that of cords and clusters of cohesive, oval-to-polygonal epithelioid cells with abundant eosinophilic cytoplasm and a mucinous background. There is often a mixed chronic inflammatory infiltrate with lymphocytes and plasma cells with Russell bodies. The main differentials for histological diagnosis include chordoid meningiomas, pilocytic astrocytomas and ependymomas. An immunohistochemical panel including antibodies to glial fibrillary acidic protein, CD34, epithelial membrane antigen, pan cytokeratin, S100 and vimentin can be used to distinguish between these possibilities. Ultrastructurally the tumour cells have basal lamina and microvilli, reminiscent of ependymomas. The clinical outcome in our cases was poor because of the location of the lesion and its close relation to the hypothalamus. Limited follow-up after surgery with or without radiotherapy suggests that as-full-as-possible resection favours a better outcome, although surgery in this area carries significant operative risks. [source] Role of axon-deprived Schwann cells in perineurial regeneration in the rat sciatic nerveNEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 3 2000M. Popovi The role of Schwann cells (SC) in perineurial regeneration after nerve injury has not yet been resolved. It was hypothesized that SC alone are able to induce at least partial morphological restoration of the destroyed orthotopic perineureum (PN). To test the hypothesis, a permanently denervated segment of the rat sciatic nerve was made acellular by freeze-thawing, except in its most proximal part where non-neuronal cells were left intact. Restoration of the frozen segment by these cells was examined by electron microscopy and immunohistochemistry of the SC marker, S-100 protein, 4 and 8 weeks after injury. The PN regenerated from undifferentiated fibroblast-like cells. In the presence of migrant SC without axons, regenerated cells in the place of the former PN were stacked in several layers and, in accordance with the hypothesis, partially expressed typical features of the perineurial cells (PC): pinocytotic vesicles, short fragments of basal lamina and tight junctions. Migrant SC induced formation of pseudo-minifascicles even in the epineurium. In these, SC organized the adjacent fibroblasts into a multilayered circular sheath, and induced their partial differentiation towards perineurial cells. Further experiments demonstrated that regenerating axons are required for complete morphological differentiation of the regenerated perineurial cells either in the orthotopic PN or in minifascicles. [source] An interdomain disulfide bridge links the NtA and first FS domain in agrinPROTEIN SCIENCE, Issue 12 2009Ainsley A. McFarlane Abstract Agrin is a multidomain heparan sulfate proteoglycan involved in postsynaptic differentiation at the neuromuscular junction. Binding of agrin to synaptic basal lamina is mediated by the N -terminal agrin (NtA) domain. The NtA domain of agrin is followed by a tandem of nine follistatin-like (FS) domains forming a rod-like spacer to the laminin G-like domains of the molecule. Here we report that the most C -terminal cysteine residue of NtA (Cys123) forms an interdomain disulfide bond with the FOLN subdomain of the FS module. Remarkably, this single cysteine is flanked by Leu117 and Val124, which are two essential ,-branched amino acids forming the heterocomplex of NtA with the ,1 chain of laminin. Moreover, we show that this covalent linkage compensates for the seven amino acid residue splice insert at the very C-terminal helix H3 and causes a rigid interface between NtA and FS independent of the alternative mRNA splice event. These results suggest that the interdomain disulfide bond between the NtA and the first FS domain might be important for the proper folding of agrin. [source] Expression and Distribution of Intermediate-filament Proteins and Laminin during the Development of the Bovine Müllerian DuctANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 3 2008R. A.-M. Summary The expression pattern of several intermediate-filament proteins (vimentin, cytokeratin 8, 18 and19) and the basal lamina component laminin was investigated in the Wolffian and the Müllerian ducts of bovine embryos and fetuses. The material studied comprised sexually undifferentiated stages [crown-rump length (CRL) 0.9 cm/1.0 cm/1.2 cm/1.9 cm/2.5 cm] and female stages (CRL 3.0 cm/4.2 cm/5.1 cm). Laminin could be demonstrated in the basal lamina of the developing Wolffian and Müllerian duct as well as in the stroma surrounding the Müllerian duct. The intermediate-filament protein vimentin was expressed in the mesothelium of the funnel field and in the epithelium of the Müllerian duct in all studied specimens, whereas the epithelial cells of the Wolffian duct only showed vimentin expression from a CRL of 2.2 cm onwards. In the cranial part of the Müllerian ducts only a few cells stained with pan-cytokeratin antibodies, whereas mesothelium and epithelium of the Wolffian duct showed as distinct immunostaining in all investigated stages. Both genital ducts showed no immunostaining with the antibody against cytokeratin 19 at any time of development. We conclude from our immunohistochemical results that the epithelial cells of the Wollfian duct do not contribute cells to the developing Müllerian duct. [source] Ultrastructural Features of Myenteric Ganglia of Adult Wistar Rats (Rattus norvegicus)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2000M. R. M. Natali Summary The ultrastructural features of the ganglia of the myenteric plexus exhibit changes according to the animal species. These myenteric ganglia in the duodenum of adult rats of the Wistar strain were characterized ultrastructurally in this work. Those ganglia were depicted as compact structures, composed of neurones and glial cells, forming a dense neuropil surrounded by a continuous basal lamina and collagen fibrils. Glial cell bodies were smaller and apparently more frequent than neuronal cell bodies, being morphologically distinguished by nuclear features. In the neuronal extensions granular and agranular synaptic vesicles of different sizes predominate, in addition to mitochondria and myelinized profiles. Gliofilaments were not observed on the glial extensions of the rats. [source] | |||||||||||||||||||||||||||||||