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Apical Regions (apical + regions)
Selected AbstractsCellular organization and appearance of differentiated structures in developing stages of the parasitic platyhelminth Echinococcus granulosusJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2005Claudio Martínez Abstract Echinococcus granulosus is the causative agent of hydatidosis, a major zoonoses that affects humans and herbivorous domestic animals. The disease is caused by the pressure exerted on viscera by hydatid cysts that are formed upon ingestion of E. granulosus eggs excreted by canine. Protoscoleces, larval forms infective to canine, develop asynchronously and clonally from the germinal layer (GL) of hydatid cysts. In this report, we describe the cellular organization and the appearance of differentiated structures both in nascent buds and developed protoscoleces attached to the GL. Early protoscolex morphogenesis is a highly complex and dynamic process starting from the constitution of a foramen in the early bud, around which nuclei are distributed mainly at the lateral and apical regions. Similarly, distribution of nuclei in mature protoscoleces is not homogenous but underlies three cellular territories: the suckers, the rostellar pad, and the body, that surrounds the foramen. Several nuclei are associated to calcareous corpuscles (Cc), differentiated structures that are absent in the earlier bud stages. The number of nuclei is similar from the grown, elongated bud stage to the mature protoscolex attached to the GL, strongly suggesting that there is no significant cellular proliferation during final protoscolex development. The amount of DNA per nucleus is in the same range to the one described for most other platyhelminthes. Our results point to a sequential series of events involving cell proliferation, spatial cell organization, and differentiation, starting in early buds at the GL of fertile hydatid cysts leading to mature protoscoleces infective to canine. © 2004 Wiley-Liss, Inc. [source] Patient motion correction for multiplanar, multi-breath-hold cardiac cine MR imagingJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2007Piotr J. Slomka PhD Abstract Purpose To correct for spatial misregistration of multi-breath-hold short-axis (SA), two-chamber (2CH), and four-chamber (4CH) cine cardiac MR (CMR) images caused by respiratory and patient motion. Materials and Methods Twenty CMR studies from consecutive patients with separate breath-hold 2CH, 4CH, and SA 20-phase cine images were considered. We automatically registered the 2CH, 4CH, and SA images in three dimensions by minimizing the cost function derived from plane intersections for all cine phases. The automatic alignment was compared with manual alignment by two observers. Results The processing time for the proposed method was <20 seconds, compared to 14,24 minutes for the manual correction. The initial plane displacement identified by the observers was 2.8 ± 1.8 mm (maximum = 14 mm). A displacement of ,5 mm was identified in 15 of 20 studies. The registration accuracy (defined as the difference between the automatic parameters and those obtained by visual registration) was 1.0 ± 0.9 mm, 1.1 ± 1.0 mm, 1.1 ± 1.2 mm, and 2.0 ± 1.8 mm for 2CH-4CH alignment and SA alignment in the mid, basal, and apical regions, respectively. The algorithm variability was higher in the apex (2.0 ± 1.9 mm) than in the mid (1.4 ± 1.4 mm) or basal (1.2 ± 1.2 mm) regions (ANOVA, P < 0.05). Conclusion An automated preprocessing algorithm can reduce spatial misregistration between multiple CMR images acquired at different breath-holds and plane orientations. J. Magn. Reson. Imaging 2007;25:965,973. © 2007 Wiley-Liss, Inc. [source] Expression of SLURP-1, an endogenous ,7 nicotinic acetylcholine receptor allosteric ligand, in murine bronchial epithelial cellsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 12 2009Kazuhide Horiguchi Abstract Mammalian secreted lymphocyte antigen-6/urokinase-type plasminogen activator receptor-related peptide-1 (SLURP-1) is a positive allosteric ligand for ,7 nicotinic acetylcholine (ACh) receptors (,7 nAChRs) that potentiates responses to ACh and elicits proapoptotic activity in human keratinocytes. Mutations in the gene encoding SLURP-1 have been detected in patients with Mal de Meleda, a rare autosomal recessive skin disorder characterized by transgressive palmoplantar keratoderma. On the basis of these findings, SLURP-1 is postulated to be involved in regulating tumor necrosis factor-, (TNF-,) release from keratinocytes and macrophages via ,7 nAChR-mediated pathways. In the present study, we assessed SLURP-1 expression in lung tissue from C57BL/6J mice to investigate the functions of SLURP-1 in pulmonary physiology and pathology. Immunohistochemical and in situ hybridization analyses revealed expression of SLURP-1 protein and mRNA, respectively, exclusively in ciliated bronchial epithelial cells. This was supported by Western blotting showing the presence of the 9.5-kDa SLURP-1 protein in whole-lung tissue and trachea. In addition, high-affinity choline transporter (CHT1) was detected in apical regions of bronchial epithelial cells and in neurons located in the lamina propria of the bronchus, suggesting that bronchial epithelial cells are able to synthesize both SLURP-1 and ACh. We also observed direct contact between F4/80-positive macrophages and bronchial epithelial cells and the presence of invading macrophages in close proximity to CHT1-positive nerve elements. Collectively, these results suggest that SLURP-1 contributes to the maintenance of bronchial epithelial cell homeostasis and to the regulation of TNF-, release from macrophages in bronchial tissue. © 2009 Wiley-Liss, Inc. [source] Analysis of the mRNA expression of the TGF-Beta family in testicular cells and localization of the splice variant TGF-,2B in testisMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 10 2006Lutz Konrad Abstract The transforming growth factors (TGF)-,, TGF-,1, TGF-,2, and TGF-,3, and their receptors [T,RI, T,RII, T,RIII (betaglycan)] elicit many functions in the testis, for example, they perturb the blood testis barrier (BTB). Although expression of the ligands and receptors have been investigated, the alternative splice variants are incompletely examined. We therefore have analyzed all ligands, the receptors, and the splice variants T,RIB, T,RIIB, and TGF-,2B in testicular cells from rat and mouse. In mouse, the novel transcript variant TGF-,2B was identified and was found in Leydig cells, spermatogonia, pachytene spermatocytes, and in the apical regions of the Sertoli cells in adult testis. Even though expression of the splice variant T,RIB could be shown in mouse and rat, we never found the isoform T,RIIB in the rat cell lines studied. Whereas in all testicular cells expression of all TGF-, ligands could be shown, receptor mRNA expression was slightly more diverse. Furthermore, expression pattern of the splice variants was more heterogeneous, for example, T,RIB was not detectable in adult Sertoli cells, primary peritubular cells, and immortalized peritubular cells. The heterogeneous expression of the receptors and especially of the splice variants might provide possible clues for the different functions of the TGF-, ligands in testicular cells. Mol. Reprod. Dev. © 2006 Wiley-Liss, Inc. [source] Apical callus formation and plant regeneration controlled by plant growth regulators on axenic culture of the red alga Gracilariopsis tenuifrons (Gracilariales, Rhodophyta)PHYCOLOGICAL RESEARCH, Issue 3 2000Nair S. Yokoya SUMMARY Axenic cultures of Gracilariopsis tenuifrons (Bird et Oliveira) Fredericq et Hommersand (Gracilariales, Rhodophyta) were established in ASP12-NTA solid medium (0.4% agar and 1.0% sucrose) supplemented with plant growth regulators to evaluate the effects on apical callus formation and plant regeneration. Indole-3-acetic acid (IAA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BA) were added individually or in combinations (IAA : BA) over a range of concentrations from 0.5 to 5 mg L,1. Growth of apical and intercalary segments was stimulated by high concentrations of 2,4-D (5 mg L,1) and a high IAA to BA ratio (IAA : BA = 5:1 mg L,1) respectively. Apical calluses were originated from divisions of apical and cortical cells located at apical regions of thallus segments and lateral branches. Low concentration of IAA (0.5 mg L,1) or a high IAA to BA ratio (IAA : BA = 5:1 mg L,1) were the optimal treatments for inducing apical callus formation in apical segments, while high concentration of IAA (5 mg L,1) stimulated the highest callus induction rate in intercalary segments. Conversely, equal parts IAA and BA (IAA : BA = 1:1 mg L,1) and low concentration of 2,4-D (0.5 mg L,1) stimulated growth of apical calluses from apical and intercalary segments, respectively. Two processes of regeneration were observed: direct regeneration (upright axis originated from cells of proximal region of intercalary segments) and indirect regeneration (adventitious plantlet originated from cells of apical calluses). Direct regeneration was promoted significantly by treatment with a low IAA to BA ratio (IAA : BA= 1:5 mg L,1), and treatments with IAA (0.5 mgL,1) or 2,4-D (0.5 or 5 mg L,1) significantly stimulated the elongation of upright axis. Plant growth regulators are essential to inducing indirect regeneration, and a high concentration of IAA (5 mg L,1) and BA (5 mg L,1) were the optimal treatments for inducing the regeneration of plantlets from apical calluses in apical and intercalary segments, respectively. Regenerating plantlets grew into plants morphologically similar to those formed from germinating spores, and became fertile after 6 weeks. The results suggest that auxins and cytokinins are involved in developmental regulatory processes in G. tenuifrons. The regeneration process from calluses in species of Gracilariales was observed for the first time in the present study. The culture system described for G. tenuifrons could be useful for micropropagation and for biotechnological applications in agarophytic algae. [source] | ||||||||||