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Granular Layer (granular + layer)
Kinds of Granular Layer Selected AbstractsThe expression of Scratch genes in the developing and adult brainDEVELOPMENTAL DYNAMICS, Issue 9 2006Faustino Marín Abstract The Scratch genes belong to the Snail superfamily of zinc-finger transcription factors present in the metazoa, represented in mammals by the Scratch1 and Scratch2 genes. We have analyzed the expression of these genes in the brain of mice at developmental stages between 9.5 days-post-coitum to adulthood. Both genes are expressed in the mantle layer of the neuroepithelium at mid-gestational stages in all regions except for the region corresponding to the V2 interneuron column, which lacked Scratch2 transcripts. From perinatal to adult stages, the expression patterns of the two genes differ. Scratch1 remains strongly expressed in almost all brain regions, although it is not found in some ventral structures such as motor nuclei and hypothalamic regions. In contrast, Scratch2 expression progressively diminishes and virtually no expression can be detected in the adult brain. Nevertheless, strong expression of Scratch2 is retained in the postnatal cortical subventricular zone, in the inner part of the cerebellar external granular layer, and in the glial cells of the adult vomeronasal nerve. Developmental Dynamoics 235:2586,2591, 2006. © 2006 Wiley-Liss, Inc. [source] In vivo analysis reveals different apoptotic pathways in pre- and postmigratory cerebellar granule cells of rabbitDEVELOPMENTAL NEUROBIOLOGY, Issue 4 2004Laura Lossi Abstract Naturally occurring neuronal death (NOND) has been described in the postnatal cerebellum of several species, mainly affecting the cerebellar granule cells (CGCs) by an apoptotic mechanism. However, little is known about the cellular pathway(s) of CGC apoptosis in vivo. By immunocytochemistry, in situ detection of fragmented DNA, electron microscopy, and Western blotting, we demonstrate here the existence of two different molecular mechanisms of apoptosis in the rabbit postnatal cerebellum. These two mechanisms affect CGCs at different stages of their maturation and migration. In the external granular layer, premigratory CGCs undergo apoptosis upon phosphorylation of checkpoint kinase 1 (Chk1), and hyperphosphorylation of retinoblastoma protein. In postmigratory CGCs within the internal granular layer, caspase 3 and to a lesser extent 7 and 9 are activated, eventually leading to poly-ADP-ribose polymerase-1 (PARP-1) cleavage and programmed cell death. We conclude that NOND of premigratory CGCs is linked to activation of DNA checkpoint and alteration of normal cell cycle, whereas in postmigratory CGCs apoptosis is, more classically, dependent upon caspase 3 activation. © 2004 Wiley Periodicals, Inc. J Neurobiol 60: 437,452, 2004 [source] Environmental impoverishment and aging alter object recognition, spatial learning, and dentate gyrus astrocytesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2010Daniel G. Diniz Abstract Environmental and age-related effects on learning and memory were analysed and compared with changes observed in astrocyte laminar distribution in the dentate gyrus. Aged (20 months) and young (6 months) adult female albino Swiss mice were housed from weaning either in impoverished conditions or in enriched conditions, and tested for episodic-like and water maze spatial memories. After these behavioral tests, brain hippocampal sections were immunolabeled for glial fibrillary acid protein to identify astrocytes. The effects of environmental enrichment on episodic-like memory were not dependent on age, and may protect water maze spatial learning and memory from declines induced by aging or impoverished environment. In the dentate gyrus, the number of astrocytes increased with both aging and enriched environment in the molecular layer, increased only with aging in the polymorphic layer, and was unchanged in the granular layer. We suggest that long-term experience-induced glial plasticity by enriched environment may represent at least part of the circuitry groundwork for improvements in behavioral performance in the aged mice brain. [source] TARPs ,-2 and ,-7 are essential for AMPA receptor expression in the cerebellumEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2010Maya Yamazaki Abstract The ,-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors require auxiliary subunits termed transmembrane AMPA receptor regulatory proteins (TARPs), which promote receptor trafficking to the cell surface and synapses and modulate channel pharmacology and gating. Of six TARPs, ,-2 and ,-7 are the two major TARPs expressed in the cerebellum. In the present study, we pursued their roles in synaptic expression of cerebellar AMPA receptors. In the cerebellar cortex, ,-2 and ,-7 were preferentially localized at various asymmetrical synapses. Using quantitative Western blot and immunofluorescence, we found severe reductions in GluA2 and GluA3 and mild reduction in GluA4 in ,-2-knockout (KO) cerebellum, whereas GluA1 and GluA4 were moderately reduced in ,-7-KO cerebellum. GluA2, GluA3 and GluA4 were further reduced in ,-2/,-7 double-KO (DKO) cerebellum. The large losses of GluA2 and GluA3 in ,-2-KO mice and further reductions in DKO mice were confirmed at all asymmetrical synapses examined with postembedding immunogold. Most notably, the GluA2 level in the postsynaptic density fraction, GluA2 labeling density at parallel fiber,Purkinje cell synapses, and AMPA receptor-mediated currents at climbing fiber,Purkinje cell synapses were all reduced to approximately 10% of the wild-type levels in DKO mice. On the other hand, the reduction in GluA4 in ,-7-KO granular layer reflected its loss at mossy fiber,granule cell synapses, whereas that of GluA1 and GluA4 in ,-7-KO molecular layer was caused, at least partly, by their loss in Bergmann glia. Therefore, ,-2 and ,-7 cooperatively promote synaptic expression of cerebellar AMPA receptors, and the latter also promotes glial expression. [source] Distinct expression of C1q-like family mRNAs in mouse brain and biochemical characterization of their encoded proteinsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2010Takatoshi Iijima Abstract Many members of the C1q family, including complement C1q and adiponectin, and the structurally related tumor necrosis factor family are secreted and play crucial roles in intercellular signaling. Among them, the Cbln (precerebellin) and C1q-like (C1ql) subfamilies are highly and predominantly expressed in the central nervous system. Although the Cbln subfamily serve as essential trans-neuronal regulators of synaptic integrity in the cerebellum, the functions of the C1ql subfamily (C1ql1,C1ql4) remain unexplored. Here, we investigated the gene expression of the C1ql subfamily in the adult and developing mouse brain by reverse transcriptase-polymerase chain reaction and high-resolution in-situ hybridization. In the adult brain, C1ql1,C1ql3 mRNAs were mainly expressed in neurons but weak expression was seen in glia-like structures in the adult brain. The C1ql1 mRNA was predominantly expressed in the inferior olive, whereas the C1ql2 and C1ql3 mRNAs were strongly coexpressed in the dentate gyrus. Although the C1ql1 and C1ql3 mRNAs were detectable as early as embryonic day 13, the C1ql2 mRNA was observed at later embryonic stages. The C1ql1 mRNA was also expressed transiently in the external granular layer of the cerebellum. Biochemical characterization in heterologous cells revealed that all of the C1ql subfamily proteins were secreted and they formed both homomeric and heteromeric complexes. They also formed hexameric and higher-order complexes via their N-terminal cysteine residues. These results suggest that, like Cbln, the C1ql subfamily has distinct spatial and temporal expression patterns and may play diverse roles by forming homomeric and heteromeric complexes in the central nervous system. [source] Comparative distribution of the mammalian mediator subunit thyroid hormone receptor-associated protein (TRAP220) mRNA in developing and adult rodent brainEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2002Anastasia Galeeva Abstract TRAP220 (thyroid hormone receptor-associated protein) is a recently cloned nuclear receptor coactivator, which interacts with several nuclear receptors in a ligand-dependent manner and stimulates transcription by recruiting the TRAP mediator complex to hormone responsive promoter regions. TRAP220 has been shown to interact with thyroid hormone receptors, vitamin D receptors, peroxisome proliferator-activated receptors, retinoic acid receptors and oestrogen receptors. Thyroid hormone and retinoic acid play very important roles in brain development and they also influence adult brain. Using in situ hybridization we have examined expression of TRAP220 mRNA in the central nervous system during development and in adult rat and mouse brain. Expression of TRAP220 was seen already during early embryonic development in the epithelium of neural tube at E9 in mouse and at E12 in rat. At later stages of development the strongest signal was seen in different layers of cerebral neocortex, external germinal layer of cerebellum, differentiating fields of hippocampus and neuroepithelium, and a moderate signal was detected in basal ganglia, different areas of diencephalon and midbrain. In adult rat brain the signal was more restricted than during development. TRAP220 expression occurred mostly in the granular layer of cerebellar cortex, piriform cortex and hippocampal formation. The signal was found predominantly in neurons. Our work supports the assumption that TRAP220 plays an important role in growth and differentiation of central nervous system and may have a function in certain areas of adult brain. [source] NMDA receptor subunits GluR,1, GluR,3 and GluR,1 are enriched at the mossy fibre,granule cell synapse in the adult mouse cerebellumEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2001Kazuyuki Yamada Abstract Cerebellar N -methyl- d -aspartate (NMDA) receptors are concentrated in the granular layer and are involved in motor coordination and the induction of long-term potentiation at mossy fibre,granule cell synapses. In the present study, we used immunohistochemistry to examine the distribution of NMDA receptor subunits in the adult mouse cerebellum. We found that appropriate pepsin pretreatment of sections greatly enhanced the sensitivity and specificity of immunohistochemical detection. As a result, intense immunolabelling for GluR,1 (NR2A), GluR,3 (NR2C), and GluR,1 (NR1) all appeared in synaptic glomeruli of the granular layer. Double immunofluorescence showed that these subunits were colocalized in individual synaptic glomeruli. Within the glomerulus, NMDA receptor subunits were located between centrally-located huge mossy fibre terminals and peripherally-located tiny Golgi axon terminals. By immunoelectron microscopy, all three subunits were detected at the postsynaptic junction in granule cell dendrites, forming synapses with mossy fibre terminals. Consistent with the known functional localization, GluR,1, GluR,3, and GluR,1 are, thus, anatomically concentrated at the mossy fibre,granule cell synapse. By contrast, immunohistochemical signals were very low in Purkinje cell somata and dendrites in the molecular layer. The lack of GluR,1 immunolabelling in Purkinje cells was unexpected because the cells express GluR,1 mRNA at high levels and high levels of GluR,1 protein in the molecular layer were revealed by immunoblot. As Purkinje cells are exceptionally lacking GluR, expression, the discrepant result may provide in vivo evidence suggesting the importance of accompanying GluR, subunits in synaptic localization of GluR,1. [source] Distribution of mossy fibre rosettes in the cerebellum of cat and mice: evidence for a parasagittal organization at the single fibre levelEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2001Fahad SultanArticle first published online: 20 DEC 200 Abstract Mossy fibres are the main afferent input to the granular layer of the cerebellar cortex. In this study, the spatial distribution of the mossy fibres' presynaptic enlargements , the so-called rosettes , were analysed on the single fibre level. Data obtained from the cerebella of cat and mice were compared to look for species differences, and the cerebella of the adult and young mice were also compared to look for developmental changes. The results show that there is a spatial anisotropy in all mossy fibres studied, with neighbouring rosettes being about three times further away from each other along the parasagittal axis and closer to each other in the mediolateral direction. Furthermore, these results suggest that this anisotropy is established at an early developmental stage. The anisotropic orientation of mossy fibres at the single fibre level supports the hypothesis of a timing mechanism in cerebellar function. [source] Opioids intrinsically inhibit the genesis of mouse cerebellar granule neuron precursors in vitro: differential impact of , and , receptor activation on proliferation and neurite elongationEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2000Kurt F. Hauser Abstract Although opioids are known to affect neurogenesis in vivo, it is uncertain the extent to which opioids directly or indirectly affect the proliferation, differentiation or death of neuronal precursors. To address these questions, the intrinsic role of the opioid system in neurogenesis was systematically explored in cerebellar external granular layer (EGL) neuronal precursors isolated from postnatal mice and maintained in vitro. Isolated neuronal precursors expressed proenkephalin-derived peptides, as well as specific , and ,, but negligible ,, opioid receptors. The developmental effects of opioids were highly selective. Morphine-induced , receptor activation inhibited DNA synthesis, while a preferential ,2 -receptor agonist ([d -Ala2]-deltorphin II) or Met-enkephalin, but not the ,1 agonist [d -Pen2, d -Pen5]-enkephalin, inhibited differentiation within the same neuronal population. If similar patterns occur in the developing cerebellum, spatiotemporal differences in endogenous , and , opioid ligand,receptor interactions may coordinate distinct aspects of granule neuron maturation. The data additionally suggest that perinatal exposure to opiate drugs of abuse directly interfere with cerebellar maturation by disrupting normal opioid signalling and inhibiting the proliferation of granule neuron precursors. [source] Dose-dependent long-term effects of Tat in the rat hippocampal formation: A design-based stereological studyHIPPOCAMPUS, Issue 4 2010Sylvia Fitting Abstract The human immunodeficiency virus type 1 (HIV-1) protein transactivator of transcription (Tat) is believed to play a critical role in mediating central nervous system (CNS) pathology in pediatric HIV-1 infection. Long-term neurotoxicity was investigated in a design-based stereology study following intrahippocampal injection of Tat on postnatal day (P)10, a time period that approximates the peak in the rats' rate of brain growth and mimics clinical HIV-1 CNS infection at labor/delivery. The goal was to examine the impact of P10 intrahippocampal Tat injection on the anatomy of the adult hippocampus (5 month) to gain a better understanding about how timing of infection influences the rate of progression of pediatric HIV-1 infection [cf. Fitting et al. (2008a) Hippocampus 18:135,147]. Male P10 Sprague-Dawley rats were bilaterally injected with vehicle or one of three different doses of Tat (5, 25, or 50 ,g). Unbiased stereological estimates were used to quantify total neuron number (Nissl stain) in five major subregions of the rat hippocampus: granular layer (GL), hilus of the dentate gyrus (DGH), cornu ammonis fields (CA)2/3, CA1, and subiculum (SUB). Glial cells (astrocytes and oligodendrocytes) were quantified in the DGH and SUB. No significant reduction of neuron number was noted for any of the five hippocampal subregions, in contrast to the very prominent reductions reported when Tat was administered on P1 [Fitting et al. (2008a) Hippocampus 18:135,147]. However, for glial cells, the number of astrocytes in the DGH and SUB as well as the number of oligodendrocytes in the DGH were linear dose dependently increased as a function of dose of Tat. In conjunction with previous stereological research [Fitting et al., (2008a) Hippocampus 18:135,147], the present data suggest that variability in the progression of pediatric HIV/acquired immunodeficiency syndrome (AIDS) may be better understood with the knowledge of the factor of timing of HIV-1 CNS infection. © 2009 Wiley-Liss, Inc. [source] Annular atrophic lichen planusINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 5 2007Rosa María Ponce-Olivera MD A 30-year-old woman presented with a 1-year history of a pruritic eruption on the extremities, characterized by several annular plaques. The patient had been treated unsuccessfully with medium-potency topical steroids. The lesions had an erythematous papular border with an atrophic center (width, 1,4 cm) (Fig. 1). No oral, genital, or nail lesions were observed. Figure 1. Annular lesion with an infiltrated border and atrophic center A skin biopsy from one of the plaques was performed. Histopathologic examination of the raised border showed hyperkeratosis of the stratum corneum, focal thickening of the granular layer, basal liquefaction degeneration of the epidermis, and a band-like subepidermal infiltration with numerous Civatte bodies. In the center of the lesion, the epidermis became thinner (Fig. 2). Elastic fibers were reduced or absent in the papillary dermis. Figure 2. (a) Biopsy of the border of a plaque with the typical changes of lichen planus (hematoxylin and eosin, ×10), with flattened epidermis in the center of the plaque; (b) medium power of the border of the plaque with details of the changes of lichen planus (hematoxylin and eosin, ×40) The patient was treated with high-potency topical steroids for 2 months with clinical improvement. [source] Non-pustular palmoplantar psoriasis: is histologic differentiation from eczematous dermatitis possible?JOURNAL OF CUTANEOUS PATHOLOGY, Issue 2 2008Ovgu Aydin Both palmoplantar psoriasis and eczematous dermatitis of this skin area share similar histologic features. The punch biopsies from 17 patients with psoriasis and 25 with eczematous dermatitis were evaluated, blind to the clinical diagnosis. Vertically situated multiple foci of parakeratosis, alternating with orthokeratosis, were the only statistically significant feature in the differential diagnosis of palmoplantar psoriasis [76.5% (13/17), p = 0.005]. In contrast, multiple foci of parakeratosis [70.6% (12/17)], loss of granular layer at least in focal areas [41.2% (7/17)], presence of neutrophils at the summits of parakeratosis [4% (1/17)], presence of neutrophils and/or plasma in the parakeratotoic foci [94.1% (16/17) and 11.8% (2/17)], psoriasiform epidermal hyperplasia [88.2% (15/17)], spongiosis restricted to the lower parts of the epidermis [47.1% (8/17)], dyskeratotic cells [82.4% (14/17)], thinning of suprapapillary plate [58.8% (10/17)], edema of the papillary dermis [29.4% (5/17)], presence of tortous and dilated capillaries in the papillary dermis [52.9% (9/17) and 76.5% (13/17)] and extravasated erythrocytes [29.4% (5/17)] were found to be more common in palmoplantar psoriasis compared with eczematous dermatitis; but none of them was statistically significant. Interestingly, spongiotic vesicles were seen in most of the patients with psoriasis [76.5% (13/17)]. In conclusion, according to our findings, many features of palmoplantar psoriasis overlapped with those of eczematous dermatitis. However, detection of multiple parakeratotic foci, placed vertically, alternating with orthohyperkeratosis, could be considered in favor of palmoplantar psoriasis. [source] Febrile Ulceronecrotic Mucha-habermann Disease: a Rare, Severe VariantJOURNAL OF CUTANEOUS PATHOLOGY, Issue 1 2006Michele M. Thompson A 56 year old Hispanic man presented with extensive ulcerative skin lesions, involving his lower trunk, groin and upper legs, severe pain and a temperature of 38.7 degrees Celsius. He was admitted to the Medical Intensive Care Unit for empiric intravenous antibiotics. Several biopsies were performed. In the following days his condition worsened and ulcerative lesions involved nearly all of his skin. Previous biopsies were consistent with pityriasis lichenoides et varioliformis acuta (PLEVA), however, neither this, nor others in the histological differential diagnosis, fit his severe and worsening clinical picture. Histology revealed vacuolar alteration with dyskeratotic keratinocytes and a superficial perivascular mixed infiltrate of lymphocytes and eosinophils. There was confluent parakeratosis containing neutrophils, and a diminished granular layer with pallor in the upper portion of the spinous layer. Immunofluorescence studies were negative. These findings were consistent with PLEVA. A clinical diagnosis of febrile ulceronecrotic Mucha-Habermann disease was made. Febrile ulceronecrotic Mucha-Habermann disease is a rare and severe variant of PLEVA characterised by high fever and papulonecrotic skin lesions. Twenty-five cases have been previously reported. We present the clinical and histological findings in this unusual clinical presentation. [source] Bilateral Systematized Porokeratotic Eccrine Ostial and Dermal Duct Nevus with Unilateral Breast HypoplasiaJOURNAL OF CUTANEOUS PATHOLOGY, Issue 1 2005A. Jayaraman Porokeratotic eccrine ostial and dermal duct nevus (PEODDN) is a rare hamartomatous malformation of the eccrine duct which typically presents at birth or early in life. Multiple punctate pits and verrucous papules and plaques with nonfollicular hyperkeratotic spines are seen over the palms and soles and may extend to the distal extremities. A linear distribution may be present. A wide range of involvement has been reported in the literature, including bilateral systematized involvement. No systemic involvement has been linked to PEODDN to date. Histologic findings are characteristic and include a dilated eccrine acrosyringium with an overlying parakeratotic column or cornoid lamella. There is slight dyskeratosis and loss of the granular layer under the cornoid lamella. Here, we present a case of bilateral systematized PEODDN in an otherwise healthy, 18 year-old Hispanic female. Physical examination is notable for marked hypoplasia of the left breast with overlying verrucous papules and plaques. Multiple punch biopsies were performed and showed findings diagnostic of PEODDN. To our knowledge, this is the most extensive involvement of PEODDN reported in the literature to date and the only case with associated hypoplasia of the breast. [source] Porokeratosis-like Changes in Chondrodermatitis Nodularis Helicis:Consequence or Coincidence?JOURNAL OF CUTANEOUS PATHOLOGY, Issue 1 2005R.N. Page Background:, Chondrodermatitis nodularis helicis (CNH) is a condition with known predisposing factors, but of unknown etiology. A variety of opinions exist as to the cause of this condition, without consensus. Design: We reviewed 111 cases of CNH from 103 patients at our laboratory. p53 immunohistochemical staining, which is over expressed in basilar epidermal cells of porokeratosis, was performed in a representative sample of CNH cases. Histologic changes characteristic of porokeratosis were qualified as a 1) parakeratotic column of keratinocytes 2) an attenuated to absent granular layer, and 3) adjacent or underlying dyskeratosis of keratinocytes, present in columns or aggregates. Results: Porokeratosis-like changes were identified in 77 of 111 cases. p53 staining was noncontributory. Conclusion: The presence of these porokeratosis-like changes in 69% of cases is intriguing. It is not clear whether or not this could possibly represent a causative mechanism or, perhaps, an otherwise coincident histologic change. The presence of porokeratosis-like changes in CNH provides a possible hypothesis in relationship to its etiology, at the very least, it could provide some histologic clue as to the presence of this deep dermal process in superficial biopsies. [source] Developmental change and function of chondroitin sulfate deposited around cerebellar Purkinje cellsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2005Yumiko Shimazaki Abstract Chondroitin sulfate is a long sulfated polysaccharide with enormous structural heterogeneity that binds with various proteins, such as growth factors, in a structure-dependent manner. In this study, we analyzed the expression of chondroitin sulfate in the postnatally developing cerebellar cortex by using three monoclonal antibodies against chondroitin sulfate, MO-225, 2H6, and CS-56, which recognize different structural domains in this polysaccharide. During the first postnatal week, the patterns of immunohistochemical staining made by these antibodies were quite similar, and the molecular layer, the granule cell layer, and Bergmann glial fibers in the external granular layer were densely stained. After postnatal day 12 (P12), the expression of 2H6 epitopes was down-regulated in the molecular layer, and the expression of CS-56 epitopes in this layer was also reduced after P16. On the other hand, the strong expression of MO-225 epitopes, GlcA(2S),1,3GalNAc(6S) (D unit)-containing structures, remained until adulthood. These chondroitin sulfate epitopes were observed around Purkinje cells, including cell soma and dendrites. Detailed immunohistochemical analysis suggested that chondroitin sulfate was deposited between Purkinje cell surfaces and the processes of Bergmann glia. Furthermore, the amount of pleiotrophin, a heparin-binding growth factor, in the cultured cerebellar slices was remarkably diminished after treatment with chondroitinase ABC or D unit-rich chondroitin sulfate. With the previous findings that pleiotrophin binds to D unit-rich chondroitin sulfate, we suggest that the D-type structure is important for the signaling of pleiotrophin, which plays roles in Purkinje cell,Bergmann glia interaction, and that the structural changes of chondroitin sulfate regulate this signaling pathway. © 2005 Wiley-Liss, Inc. [source] Psoriasis under the microscopeJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 2006BJ Cribier Abstract Histopathology is a major diagnostic tool in dermatology, particularly in psoriasiform diseases. Morphological studies showed that the initial event in psoriatic lesions is perivascular infiltrate, followed by dilatation of superficial papillary vessels. Proliferation of keratinocytes and neutrophil exocytosis are secondary events. Fully developed psoriasis has a very characteristic pattern, which includes elongation of rete ridges leading to regular acanthosis, oedema of the papillary dermis associated with tortuous dilated vessels, thinning of suprapapillar area, decreased thickness of granular layer, and exocytosis of neutrophils in the spinous layer (Kogoj's pustule) or in the cornified parakeratotic layer (Munro microabscesses). Pustular psoriasis is characterized by large or confluent intra-epidermal multilocular pustules. Whatever the clinical variant of psoriasis, common morphological signs suggest that it is basically a unique pathological process, with many possible presentations according to various factors such as age, size and localization of lesions, or therapy. Similar microscopic elementary lesions indicate that Hallopeau's acrodermatitis continua, Reiter's disease and geographical tongue are variants of psoriasis. Because of the many faces of the disease, psoriasis can resemble many other squamous or pustular disorders. Differential diagnosis by microscopic analysis is based on pattern analysis, PAS (Periodic Acid Schiff) staining to rule out fungal infection, and immunohistochemistry to characterize lymphocytic infiltrate. Psoriasis is one of the most common inflammatory skin diseases. In its characteristic presentation, psoriasis comprises well-circumscribed red scaly papules and plaques. In this form, the disease is generally easy to identify, especially when the elbows, knees and scalp are affected. Nevertheless, the term ,psoriasis' includes more clinical variants than any other inflammatory dermatosis: psoriasis vulgaris vs. pustular, localized vs. generalized, topographic variants, mucous membranes involvement, hair and nail lesions. Although some of these conditions might be extremely different from psoriasis vulgaris, common pathological findings can be identified in all of them. Microscopic analysis of psoriatic lesions may therefore help clinicians to make the diagnosis and to understand that, whatever the clinical presentation, signs and symptoms are mainly due to a unique pathological process. [source] Circumscribed palmar hypokeratosis: clinical evolution and ultrastructural study after prolonged treatment with topical calcipotriolJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 4 2005F Urbina Abstract Circumscribed palmar hypokeratosis is a recently described condition that consists of a solitary area of depressed skin affecting the palm (or sole). Its histopathological features include a thinned horny layer, a slightly diminished granular cell layer, and intraepidermal vacuolated cells. Prolonged treatment with topical calcipotriol resulted in complete recovery of the affected zone in the case reported here. A second biopsy of the lesion taken at around the fourth year of therapy showed a normalization of the granular layer, a reduction in the intraepidermal vacuolated cells, and a somewhat thicker horny layer. An ultrastructural study carried out at the same time showed a reduction in keratin bundles and keratohyalin granules, and an increase in lipid droplets up to the horny layer. These findings and the therapeutic response to topical calcipotriol support the concept that circumscribed palmar hypokeratosis is a focalized abnormal keratinization defect morphologically expressed at the granular and horny layers. [source] Infant Skin Microstructure Assessed In Vivo Differs from Adult Skin in Organization and at the Cellular LevelPEDIATRIC DERMATOLOGY, Issue 2 2010Georgios N. Stamatas Ph.D. The purpose of this study was to examine infant skin microstructure in vivo and to compare it with that of adult skin. The lower thigh area of 20 healthy mothers (ages 25,43) and their biological children (ages 3,24 months) was examined using in vivo noninvasive methods including fluorescence spectroscopy, video microscopy, and confocal laser scanning microscopy. Stratum corneum and supra-papillary epidermal thickness as well as cell size in the granular layer were assessed from the confocal images. Adhesive tapes were used to remove corneocytes from the outer-most layer of stratum corneum and their size was computed using image analysis. Surface features showed differences in glyph density and surface area. Infant stratum corneum was found to be 30% and infant epidermis 20% thinner than in adults. Infant corneocytes were found to be 20% and granular cells 10% smaller than adult corneocytes indicating a more rapid cell turnover in infants. This observation was confirmed by fluorescence spectroscopy. Dermal papillae density and size distribution also differed. Surprisingly, a distinct direct structural relationship between the stratum corneum morphology and the dermal papillae was observed exclusively in infant skin. A change in reflected signal intensity at ,100 ,m indicating the transition between papillary and reticular dermis was evident only in adult skin. We demonstrate in vivo qualitative and quantitative differences in morphology between infant and adult skin. These differences in skin microstructure may help explain some of the reported functional differences. [source] Organization of tectopontine terminals within the pontine nuclei of the rat and their spatial relationship to terminals from the visual and somatosensory cortexTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 3 2005Cornelius Schwarz Abstract We investigated the spatial relationship of axonal and dendritic structures in the rat pontine nuclei (PN), which transfer visual signals from the superior colliculus (SC) and visual cortex (A17) to the cerebellum. Double anterograde tracing (DiI and DiAsp) from different sites in the SC showed that the tectal retinotopy of visual signals is largely lost in the PN. Whereas axon terminals from lateral sites in the SC were confined to a single terminal field close to the cerebral peduncle, medial sites in the SC projected to an additional dorsolateral one. On the other hand, axon terminals originating from the two structures occupy close but, nevertheless, totally nonoverlapping terminal fields within the PN. Furthermore, a quantitative analysis of the dendritic trees of intracellularly filled identified pontine projection neurons showed that the dendritic fields were confined to either the SC or the A17 terminal fields and never extended into both. We also investigated the projections carrying cortical somatosensory inputs to the PN as these signals are known to converge with tectal ones in the cerebellum. However, terminals originating in the whisker representation of the primary somatosensory cortex and in the SC were located in segregated pontine compartments as well. Our results, therefore, point to a possible pontocerebellar mapping rule: Functionally related signals, commonly destined for common cerebellar target zones but residing in different afferent locations, may be kept segregated on the level of the PN and converge only later at specific sites in the granular layer of cerebellar cortex. J. Comp. Neurol. 484:283,298, 2005. © 2005 Wiley-Liss, Inc. [source] Ultrastructure, Eneystment and Cyst Wall Composition of the Resting Cyst of the Peritrich Ciliate Opisthonecta henneguyiTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 1 2003PURIFICACIÓN CALVO ABSTRACT. The cyst wall of Opisthonecta henneguyi has been studied ultrastructurally and cytochemically by light and electron microscopy, as well as by chemical and electrophoretic analyses, to examine the structure of the cyst wall and its composition. The cyst wall consists of four morphologically distinct layers. The ectocyst is a thin dense layer. The mesocyst is the thickest layer and is composed of a compact material. The endocyst is a thin layer like the ectocyst, but less dense. The granular layer varies in thickness and is composed of a granular material. In the resting cyst, kinetosomes of both oral apparatus and trochal band as well as the myoneme system are maintained, and only cilia are resorbed. The sugars present in the cyst wall are predominantly N-acetylglucosamine (90%) and glucose (10%). The niesocyst is composed of chitin, and the endocyst includes glycoproteins and acid mucopolysaccharides. During secretion of the cyst wall, the endocyst and granular layer are secreted from precursors synthesized "de novo". No cytoplasmic precursors of ectocyst and mesocyst have been detected. [source] Sustained granule cell activity disinhibits juvenile mouse cerebellar stellate cells through presynaptic mechanismsTHE JOURNAL OF PHYSIOLOGY, Issue 2 2008Simone Astori GABA release from cerebellar molecular layer interneurons can be modulated by presynaptic glutamate and/or GABAB receptors upon perfusing the respective agonists. However, it is unclear how release and potential spillover of endogenous transmitter lead to activation of presynaptic receptors. High frequency firing of granule cells, as observed in vivo upon sensory stimulation, could lead to glutamate and/or GABA spillover. Here, we established sustained glutamatergic activity in the granule cell layer of acute mouse cerebellar slices and performed 190 paired recordings from connected stellate cells. Train stimulation at 50 Hz reduced by about 30% the peak amplitude of IPSCs evoked by brief depolarization of the presynaptic cell in 2-week-old mice. A presynaptic mechanism was indicated by changes in failure rate, paired-pulse ratio and coefficient of variation of evoked IPSCs. Furthermore, two-photon Ca2+ imaging in identified Ca2+ hot spots of stellate cell axons confirmed reduced presynaptic Ca2+ influx after train stimulation within the granular layer. Pharmacological experiments indicated that glutamate released from parallel fibres activated AMPARs in stellate cells, evoking GABA release from surrounding cells. Consequential GABA spillover activated presynaptic GABABRs, which reduced the amplitude of eIPSCs. Two-thirds of the total disinhibitory effect were mediated by GABABRs, one-third being attributable to presynaptic AMPARs. This estimation was confirmed by the observation that bath applied baclofen induced a more pronounced reduction of evoked IPSCs than kainate. Granule cell-mediated disinhibition persisted at near-physiological temperature but was strongly diminished in 3-week-old mice. At this age, GABA release probability was not reduced and presynaptic GABABRs were still detectable, but GABA uptake appeared to be advanced, attenuating GABA spillover. Thus, sustained granule cell activity modulates stellate cell-to-stellate cell synapses, involving transmitter spillover during a developmentally restricted period. [source] Intrinsic properties and mechanisms of spontaneous firing in mouse cerebellar unipolar brush cellsTHE JOURNAL OF PHYSIOLOGY, Issue 2 2007Marco J. Russo Neuronal firing patterns are determined by the cell's intrinsic electrical and morphological properties and are regulated by synaptic interactions. While the properties of cerebellar neurons have generally been studied in much detail, little is known about the unipolar brush cells (UBCs), a type of glutamatergic interneuron that is enriched in the granular layer of the mammalian vestibulocerebellum and participates in the representation of head orientation in space. Here we show that UBCs can be distinguished from adjacent granule cells on the basis of differences in membrane capacitance, input resistance and response to hyperpolarizing current injection. We also show that UBCs are intrinsically firing neurons. Using action potential clamp experiments and whole-cell recordings we demonstrate that two currents contribute to this property: a persistent TTX-sensitive sodium current and a ruthenium red-sensitive, TRP-like cationic current, both of which are active during interspike intervals and have reversal potentials positive to threshold. Interestingly, although UBCs are also endowed with a large Ih current, this current is not involved in their intrinsic firing, perhaps because it activates at voltages that are more hyperpolarized than those associated with autonomous activity. [source] The exine ultrastructure of pollen grains in Gnetum (Gnetaceae) from China and its bearing on the relationship with the ANITA GroupBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2004YI-FENG YAO Pollen grains of six species of Gnetum, G. parvifolium, G. hainanense, G. luofuense, G. pendulum, G. cleistostachyum and G. montanum, collected from China were examined using light, scanning and transmission electron microscopy. Pollen grains of Gnetum are subspheroidal or irregular-apolar, inaperturate, 11.21,22.44 µm in long axis and 9.34,20.47 µm in short axis. The exine surface is covered with spinules, 0.50(0.30,0.71) µm long spaced on average 1.12(0.81,1.46) µm apart. The exine is about 0.55 µm thick and comprises ectexine and endexine. The ectexine includes a thin tectum and an infratectal granular layer. The tectum protrudes outwards, forming the spinules. The endexine is composed of discontinuous lamellae, with lacunae between lamellae. The pollen grains of Gnetum are compared with those of Ephedra and Welwitschia, and also those of the ANITA Group of angiosperms, including Amborellaceae, Nymphaeales, Illiciales, Trimeniaceae and Austrobaileyaceae. The exine ultrastructures of Gnetum, Ephedra and Welwitschia are quite similar, consisting of tectum, granular layer and lamellated endexine. The exine ultrastructure of Gnetum is also similar to that of Nymphaea colorata (Nymphaeaceae) in the transitional region between the proximal and distal poles, but differs from that of Amborellaceae, Illicium religiosum (Illiciaceae), Schisandra (Schisandraceae), Trimeniaceae and Austrobaileyaceae. This comparison of exine ultrastructure provides new evidence for consideration of the relationship between Gnetum and the ANITA Group. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society, 2004, 146, 415,425. [source] Localization of sphingomyelin during the development of dorsal and tail epidermis of miceBRITISH JOURNAL OF DERMATOLOGY, Issue 5 2001Y. Yoshida Background The water permeability barrier of the stratum corneum seems to be regulated primarily by lamellar bodies situated between the corneocytes; the lamellar bodies originate largely from polar lipid precursors, mainly sphingomyelin (SM), provided by the cells of the stratum granulosum via exocytosis of their lamellar body content. Objectives The aim of our study was to evaluate the cellular distribution of SM during development of the epidermis. Methods In this study, we investigated the expression and localization of SM in both adult and fetal mouse skin by a cytochemical detection method, immunofluorescence microscopy and immunoelectron microscopy, using anti-SM antibody, a specific binding protein to SM (lysenin), and Nile red stain. In addition, we measured transepidermal water loss to estimate the barrier function of the fetal skin. Results We observed that SM was widely distributed from the basal layer to the granular layer in the adult mouse epidermis. An intense cytochemical reaction for SM was observed on embryonic day E14·5 of gestation just before the differentiation of the granular and squamous cells from the intermediate cells. The immunofluorescence indicating SM was detected in two regions, i.e. the most superficial zone of the granular layer and the upper spinous layer after the cell differentiation at the late gestational age. This distribution was not detected by conventional lipid staining, such as with Nile red stain. Immunoelectron microscopy revealed that SM was mainly localized in the intercellular spaces of the adult mouse epidermis and in the intracellular vesicles without a complete lamellar structure in the cytoplasm of epidermal cells of E14·5 fetuses. It is well known that the formation of the structurally mature cornified cell envelope occurs at E15·5 of development. The skin of fetuses at E16·5 showed a definite barrier function. Conclusions These findings suggest that SM dynamics is related to the formation of the lipid envelope, cell differentiation, and epidermal barrier function during development. [source] Effects of nicotine and chlorisondamine on cerebral glucose utilization in immobilized and freely-moving ratsBRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2000T Marenco Chlorisondamine blocks central nicotinic receptors for many weeks via an unknown mechanism. Intracerebroventricular administration of [3H]-chlorisondamine in rats results in an anatomically restricted and persistent intracellular accumulation of radioactivity. The initial aim of the present study was to test whether nicotinic receptor antagonism by chlorisondamine is also anatomically restricted. Male adult rats were pretreated several times with nicotine to avoid the disruptive effects of the drug seen in drug-naďve animals. They then received chlorisondamine (10 ,g i.c.v.) or saline, and local cerebral glucose utilization (LCGU) was measured 4 weeks later after acute nicotine (0.4 mg kg,1 s.c.) or saline administration. During testing, rats were partially immobilized. Nicotine significantly increased LCGU in the anteroventral thalamus and in superior colliculus. Chlorisondamine completely blocked the first of these effects. Chlorisondamine significantly reduced LCGU in the lateral habenula, substantia nigra pars compacta, ventral tegmental area, and cerebellar granular layer. The second experiment was of similar design, but the rats were not pre-exposed to nicotine, and were tested whilst freely-moving. Acute nicotine significantly increased LCGU in anteroventral thalamus, superior colliculus, medial habenula and dorsal lateral geniculate. Overall, however, nicotine significantly decreased LCGU. Most or all of the central effects of nicotine on LCGU were reversed by chlorisondamine given 4 weeks beforehand. These findings suggest that chlorisondamine blocks nicotinic effects widely within the brain. They also indicate that in freely-moving rats, nicotine can reduce or stimulate cerebral glucose utilization, depending on the brain area. British Journal of Pharmacology (2000) 129, 147,155; doi:10.1038/sj.bjp.0703005 [source] Psoriasiform skin lesion and supprative acrodermatitis associated with Kawasaki disease followed by the treatment with infliximab: a case reportACTA PAEDIATRICA, Issue 7 2010S Kishimoto Abstract A 4-month-old boy was diagnosed with Kawasaki disease. The ordinary treatments with intravenous gammaglobulin and metylpredonisolone were not effective. Infliximab (5 mg/kg) was administrated on 13th day of illness which led to defeverscence and improvement of clinical manifestations. On 23 days of illness, however, desquamative papules and plaques developed on both the extensor surfaces of the forearms and legs. In addition, typical subungual desquamations of fingers and toes followed crusted hyperkeratosis which resembled supprative acrodermatitis. Skin biopsy from the forearm showed inflammatory dyskeratosis with marked hyperkeratosis, epithelial parakeratotsis, loss of granular layer and dominant infiltration of CD8 + T-cells. Local treatment of steroid followed improvement of skin lesions within a few weeks. Conclusion:, Although previous reports described the beneficial effects of infliximab in patients with Kawasaki disease, it is possible that the administration of infliximab modify psoriasiform skin lesion associated with Kawasaki disease. [source] Enhanced T2 contrast for MR histology of the mouse brainMAGNETIC RESONANCE IN MEDICINE, Issue 4 2006Anjum Ali Sharief Abstract A 3D Carr-Purcell-Meiboom-Gill (CPMG) sequence was implemented to obtain enhanced T2 contrast in actively stained (perfusion with fixative and contrast agent) mouse brains at 9.4 T. Short interecho spacing was used to minimize diffusion and susceptibility losses. The sequence produced 16 3D volumes with an interecho spacing of 7 ms for isotropic 43-,-resolution images of the mouse brains in a scan time of 4 hr. To enhance the signal-to-noise ratio (SNR) and contrast, the multiecho frequency domain image contrast (MEFIC) method was applied, resulting in a composite image with T2 -weighted contrast. The high SNR and contrast thus achieved revealed aspects of mouse brain morphology, such as multiple cortical layers, groups of thalamic nuclei, layers of the inferior and superior colliculus, and molecular and granular layers of the cerebellum, with a high degree of definition and contrast that was not previously achieved in T2 -weighted acquisitions at high fields. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc. [source] Stage-specific Alterations of Cyclin Expression During UVB-induced Murine Skin Tumor Development,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2002Arianna L. Kim ABSTRACT We have evaluated the in vivo correlation between the expression of cell cycle markers and skin tumor development in SKH-1 hairless mice in a complete photocarcinogenesis protocol. Irradiated mice developed an average of 16 tumors per animal by week 23 with the average number of carcinomas per mouse being 2.1. The expression of p53 and cyclins A and D1 was confined initially to sporadic single cells and gradually developed into foci of patchy intense staining in the basal and granular layers of UVB-exposed epidermis. p53 was expressed in all the papilloma sections examined, whereas cyclins D1 and A were expressed in 68 and 71% of these lesions, respectively. In UVB-induced squamous cell carcinomas (SCC), p53 was expressed in >90% of the tumors, whereas cyclin D1 was detected in 55% of the lesions, and cyclin A staining was limited to 27%. These immunohistochemical observations were confirmed by Western blotting and protein kinase assays. We observed an early wave of cyclin A overexpression and cyclin A protein kinase activity preceding the appearance of detectable tumors. Cyclin D1 and p53 overexpression were coupled with the development of tumors, and these changes are likely to be relevant to the pathogenesis of these lesions. [source] | |||||||||||||