210 research outputs found

    Analysis of gastrin receptor gene expression in proliferating cells in the neck zone of gastric fundic glands using laser capture microdissection

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    AbstractGastrin stimulates proliferation of progenitor cells in the neck zone of gastric fundic mucosa. However, whether it directly enhances this proliferation through its receptors remains unclear. We investigated the expression of gastrin receptors in neck zone proliferating cells in rat gastric fundic glands using a reverse transcription polymerase chain reaction (RT-PCR) coupled with laser capture microdissection and in situ RT-PCR. Gastrin receptor expression was identified in c-fos-expressing cells located in the neck zone, and results of the RT-PCR analysis argued against contamination by other cells, such as enterochromaffin-like, parietal or D cells. Supporting this finding, gastrin receptor gene expression was identified in the neck zone as well as base glands by in situ RT-PCR. Therefore, it is suggested that proliferating cells in the neck zone are stimulated directly by gastrin via their gastrin receptors

    Elastic microfibril distribution in the cornea: Differences between normal and keratoconic stroma

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    The optical and biomechanical properties of the cornea are largely governed by the collagen-rich stroma, a layer that represents approximately 90% of the total thickness. Within the stroma, the specific arrangement of superimposed lamellae provides the tissue with tensile strength, whilst the spatial arrangement of individual collagen fibrils within the lamellae confers transparency. In keratoconus, this precise stromal arrangement is lost, resulting in ectasia and visual impairment. In the normal cornea, we previously characterised the three-dimensional arrangement of an elastic fiber network spanning the posterior stroma from limbus-to-limbus. In the peripheral cornea/limbus there are elastin-containing sheets or broad fibers, most of which become microfibril bundles (MBs) with little or no elastin component when reaching the central cornea. The purpose of the current study was to compare this network with the elastic fiber distribution in post-surgical keratoconic corneal buttons, using serial block face scanning electron microscopy and transmission electron microscopy. We have demonstrated that the MB distribution is very different in keratoconus. MBs are absent from a region of stroma anterior to Descemet's membrane, an area that is densely populated in normal cornea, whilst being concentrated below the epithelium, an area in which they are absent in normal cornea. We contend that these latter microfibrils are produced as a biomechanical response to provide additional strength to the anterior stroma in order to prevent tissue rupture at the apex of the cone. A lack of MBs anterior to Descemet's membrane in keratoconus would alter the biomechanical properties of the tissue, potentially contributing to the pathogenesis of the disease

    Oligopeptide Transporter-1 is Associated with Fluorescence Intensity of 5-Aminolevulinic Acid-Based Photodynamic Diagnosis in Pancreatic Cancer Cells

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    [Background] The 5-aminolevulinic acid (ALA)-based photodynamic diagnosis is based on the accumulation of photosensitizing protoporphyrin IX in the tumor after ALA administration. However, the mechanisms connecting exogenous ALA and tumor fluorescence in pancreatic cancer remain unclear. We aimed to elucidate the mechanism underlying the ALA-induced fluorescent. [Methods] Human pancreatic duct epithelial cells (hPDECs) and pancreatic cancer cell lines were used. The expressions of ALA-associated enzymes and membrane transporters in these cell lines were investigated. ALA-induced fluorescence was also investigated. [Results] The expression of oligopeptide transporter-1 (PEPT-1), through which ALA is absorbed, was significantly higher in AsPC-1 cells and lower in MIA PaCa-2 cells than in hPDECs. AsPC-1 cells showed rapid and intense fluorescence after ALA administration, and that was attenuated by PEPT-1 inhibition. ALA-induced fluorescence was not sufficiently strong in MIA PaCa-2 cells to distinguish the cells from hPDECs. [Conclusion] We revealed the association of PEPT-1 with ALA-induced fluorescence. Cancers expressing PEPT-1 could be easily distinguished by this technique from normal cells. These findings help develop novel diagnostic modalities for pancreatic cancer

    The structure and development of Xenopus laevis cornea.

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    The African clawed frog, Xenopus laevis, is a widely used model organism for tissue development. We have followed the process of corneal development closely in Xenopus and examined the corneal ultrastructure at each stage during its formation. Xenopus cornea development starts at stage 25 from a simple embryonic epidermis overlying the developing optic vesicle. After detachment of the lens placode which takes place around stage 30, cranial neural crest cells start to invade the space between the lens and the embryonic epidermis to construct the corneal endothelium. At stage 41, a second wave of migratory cells containing presumptive keratocytes invades the matrix leading to the formation of inner cornea and outer cornea. Three-dimensional electron microscopic examination shows that a unique cell mass, the stroma attracting center, connects the two layers like the center pole of a tent. After stage 48, many secondary stromal keratocytes individually migrate to the center and form the stroma layer. At stage 60, the stroma space is largely filled by collagen lamellae and keratocytes, and the stroma attracting center disappears. At early metamorphosis, the embryonic epithelium gradually changes to the adult corneal epithelium, which is covered by microvilli. Around stage 62 the embryonic epithelium thickens and a massive cell death is observed in the epithelium, coinciding with eyelid opening. After metamorphosis, the frog cornea has attained the adult structure of three cellular layers, epithelium, stroma, and endothelium, and two acellular layers between the cellular layers, namely the Bowman's layer and Descemet's membrane. After initial completion, Xenopus cornea, in particular the stroma, continues to thicken and continues to enlarge throughout the lifetime of the animal. In the adult, a p63 positive limbus-like wavy structure is observed at the peripheral edge of the cornea. Proliferation analysis shows that the basal corneal epithelial cells actively divide and there are a small number of proliferating cells among the stroma and endothelial cells. This study shows that the development and structure of Xenopus cornea is largely conserved with human although there are some unique processes in Xenopus

    Spontaneous intraperitoneal renal rupture with urinoma formation in the fetus

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    Spontaneous intraperitoneal renal rupture with urinoma formation in fetuses is an unusual condition that is caused by upper or lower urinary tract obstruction. We report the case of a neonatal male infant who presented with a spontaneous intraperitoneal right renal rupture accompanying ipsilateral ureterovesical junction obstruction (UVJO). Fetuses with UVJO accompanying contralateral multicystic dysplastic kidney should be observed carefully because of the risk of spontaneous renal rupture

    Leading Effects in Hadroproductions of Lambda_c and D From Constituent Quark-Diquark Cascade Picture

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    We discuss the hadroproductions of Lambda_c, Lambda_c bar, D and D bar in the framework of the constituent quark-diquark cascade model taking into account the valence quark annihilation. The spectra of Lambda_c and Lambda_c bar in pA, Sigma^-A and pi^-A collisions are well explained by the model using the values of parameters used in hadroproductions of D and D bar. It is shown that the role of valence diquark in the incident baryon is important for D bar productions as well as for Lambda_c production.Comment: 11 pages, 5 figures, v2:some explanations added, references added, typos corrected, v3: top margin change

    CSC with and without steroids

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    We investigated the rates of the use of steroids in Japanese central serous chorioretinopathy (CSC) cases and differences in the characteristics of CSC with and without steroids. A total of 538 eyes of 477 patients diagnosed with CSC, with 3 months or more of follow-up between April 2013 and June 2017 at 8 institutions. Patients with CSC with more than 3 months of follow-up were identified by OCT and fluorescein angiography at 8 institutions. Data collected included patient demographics, history of corticosteroid medication and smoking, spherical errors, findings of angiography, subfoveal choroidal thickness, and changes through the follow-up period. Differences in these findings were analyzed in cases with and without corticosteroid treatment. Among the 477 patients (344 men,133 women), 74 (15.5%) (39 men, 35 women) underwent current or prior steroid treatment. Cases with steroids were higher age (p = 0.0403) and showed no male prevalence, more bilateral involvement (p < 0.0001), and the affected eyes had multiple pigment epithelial detachment (p <0.0001), more fluorescein leakage sites (p < 0.0001), greater choroidal thickness (p = 0.0287) and a higher recurrence rate (p = 0.0412). Steroids can cause severer CSC through an effect on choroidal vessels and an impairment of retinal pigment epithelium
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