Protogenin, a new member of the immunoglobulin superfamily, is implicated in the development of the mouse lower first molar

<p>Abstract</p> <p>Background</p> <p><it>Protogenin (Prtg) </it>has been identified as a gene which is highly expressed in the mouse mandible at embryonic day 10.5 (E10.5) by a cDNA subtraction method between mandibles at E10.5 and E12.0. Prtg is a new member of the deleted in colorectal carcinoma (DCC) family, which is composed of DCC, Neogenin, Punc and Nope. Although these members play an important role in the development of the embryonic central nervous system, recent research has also shed on the non-neuronal organization. However, very little is known regarding the fetal requirement of the non-neuronal organization for Prtg and how this may be associated with the tooth germ development. This study examined the functional implications of Prtg in the developing tooth germ of the mouse lower first molar.</p> <p>Results</p> <p>Ptrg is preferentially expressed in the early stage of organogenesis. Prtg mRNA and protein were widely expressed in the mesenchymal cells in the mandible at E10.5. The oral epithelial cells were also positive for Prtg. The expression intensity of Prtg after E12.0 was markedly reduced in the mesenchymal cells of the mandible, and was restricted to the area where the tooth bud was likely to be formed. Signals were also observed in the epithelial cells of the tooth germ. Weak signals were observed in the inner enamel epithelial cells at E16.0 and E18.0. An inhibition assay using a hemagglutinating virus of Japan-liposome containing <it>Prtg </it>antisense-phosphorothioated-oligodeoxynucleotide (AS-S-ODN) in cultured mandibles at E10.5 showed a significant growth inhibition in the tooth germ. The relationship between Prtg and the odontogenesis-related genes was examined in mouse E10.5 mandible, and we verified that the Bmp-4 expression had significantly been decreased in the mouse E10.5 mandible 24 hr after treatment with Prtg AS-S-ODN.</p> <p>Conclusion</p> <p>These results indicated that the <it>Prtg </it>might be related to the initial morphogenesis of the tooth germ leading to the differentiation of the inner enamel epithelial cells in the mouse lower first molar. A better understanding of the Prtg function might thus play a critical role in revealing a precious mechanism in tooth germ development.</p

Structure of Musashi1 in a complex with target RNA: the role of aromatic stacking interactions

Mammalian Musashi1 (Msi1) is an RNA-binding protein that regulates the translation of target mRNAs, and participates in the maintenance of cell ‘stemness’ and tumorigenesis. Msi1 reportedly binds to the 3′-untranslated region of mRNA of Numb, which encodes Notch inhibitor, and impedes initiation of its translation by competing with eIF4G for PABP binding, resulting in triggering of Notch signaling. Here, the mechanism by which Msi1 recognizes the target RNA sequence using its Ribonucleoprotein (RNP)-type RNA-binding domains (RBDs), RBD1 and RBD2 has been revealed on identification of the minimal binding RNA for each RBD and determination of the three-dimensional structure of the RBD1:RNA complex. Unique interactions were found for the recognition of the target sequence by Msi1 RBD1: adenine is sandwiched by two phenylalanines and guanine is stacked on the tryptophan in the loop between β1 and α1. The minimal recognition sequences that we have defined for Msi1 RBD1 and RBD2 have actually been found in many Msi1 target mRNAs reported to date. The present study provides molecular clues for understanding the biology involving Musashi family proteins

Rib fracture after stereotactic radiotherapy on follow-up thin-section computed tomography in 177 primary lung cancer patients

<p>Abstract</p> <p>Background</p> <p>Chest wall injury after stereotactic radiotherapy (SRT) for primary lung cancer has recently been reported. However, its detailed imaging findings are not clarified. So this study aimed to fully characterize the findings on computed tomography (CT), appearance time and frequency of chest wall injury after stereotactic radiotherapy (SRT) for primary lung cancer</p> <p>Materials and methods</p> <p>A total of 177 patients who had undergone SRT were prospectively evaluated for periodical follow-up thin-section CT with special attention to chest wall injury. The time at which CT findings of chest wall injury appeared was assessed. Related clinical symptoms were also evaluated.</p> <p>Results</p> <p>Rib fracture was identified on follow-up CT in 41 patients (23.2%). Rib fractures appeared at a mean of 21.2 months after the completion of SRT (range, 4 -58 months). Chest wall edema, thinning of the cortex and osteosclerosis were findings frequently associated with, and tending to precede rib fractures. No patients with rib fracture showed tumors > 16 mm from the adjacent chest wall. Chest wall pain was seen in 18 of 177 patients (10.2%), of whom 14 patients developed rib fracture. No patients complained of Grade 3 or more symptoms.</p> <p>Conclusion</p> <p>Rib fracture is frequently seen after SRT for lung cancer on CT, and is often associated with chest wall edema, thinning of the cortex and osteosclerosis. However, related chest wall pain is less frequent and is generally mild if present.</p

マウス胎仔口蓋突起におけるI型及びIII型コラ-ゲンとフィブロネクチンの分布に関する免疫電子顕微鏡学的研究

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Regulation of Mandible Fracture Healing - An Immunohistochemical Study in Rat

Fracture healing is a sequence of events that involves a combination of intramembranous and endochondral ossification. During fracture healing, a number of growth factors and important cytokines such as BMP-2, BMP-4, TGF-β, and PDGF-B and Osteopontin are present at elevated levels in and around the fracture site, suggesting that they play an active role in promoting fracture healing. The regulation of fracture repair by important growth factors and cytokines in a mandible fracture has not been clearly understood. Taking this into consideration, we want to know about the control mechanism that the coordinates recruitment, localization, and function of different cell populations at the mandible fracture. In this study, we present 48 Wistar rats that have their right ramus mandible fractured with a bending clamp. On days 3, 7, 14 and 21 after the operation the animals were sacrificed with perfusion technique. For immunohistochemistry we used goat polyclonal antiboy for BMP-2 and BMP-4, rabbit polyclonal antibody for TGF-β and PDGF-B, and mouse monoclonal antibody for Osteopontin as the primary antibody. The presence and localized of these cytokines were analyzed

lmmunocytochemistry of perinatal rat livers with a special reference to the roles of mesenchymal cells in hepatic differentiation

To investigate the roles of extracellular matrix produced by hepatic mesenchymal cells in the organization of hepatic cell cords, perinatal rat livers were examined with immunocytochemistry of fibronectin (FN) and larninin (LM). Some hepatocytes in a free state at prenatal day 15 actively produced FN and LM in the rough endoplasmic reticulum but lost this synthetic activity when such cells were incorporated into hepatic cell cords. On the other hand, hepatic mesenchymal cells, especially those associated with the perisinusoidal space, retained this synthetic activity throughout the stages examined. In the differentiating hepatic cell cords, positive imrnunoreactions for FN and LM were preferentially seen on the cell surface facing both sinusoidal space and differentiating bile canaiiculus concomitant with the expression of the tight junction protein, ZO-1, from prenatal day 17. Since such hepatocytes have lost or reduced their synthetic activities of both glycoproteins in the rER, the immunoreactions appear to be mainly due to hepatic mesenchymal cells which seem to play a role in the formation of the hepatic cell cords and the bile canaliculi