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Remaining Portion (remaining + portion)
Selected AbstractsMeltwater discharge through the subglacial bed and its land-forming consequences from numerical experiments in the Polish lowland during the last glaciationEARTH SURFACE PROCESSES AND LANDFORMS, Issue 4 2009Jan A. Piotrowski Abstract Numerical experiments suggest that the last glaciation severely affected the upper lithosphere groundwater system in NW Poland: primarily its flow pattern, velocities and fluxes. We have simulated subglacial groundwater flow in two and three spatial dimensions using finite difference codes for steady-state and transient conditions. The results show how profoundly the ice sheet modifies groundwater pressure heads beneath and some distance beyond the ice margin. All model runs show water discharge at the ice forefield driven by ice-sheet-thickness-modulated, down-ice-decreasing hydraulic heads. In relation to non-glacial times, the transient 3D model shows significant changes in the groundwater flow directions in a regionally extensive aquifer ca. 90 m below the ice,bed interface and up to 40 km in front of the glacier. Comparison with empirical data suggests that, depending on the model run, only between 5 and 24% of the meltwater formed at the ice sole drained through the bed as groundwater. This is consistent with field observations documenting abundant occurrence of tunnel valleys, indicating that the remaining portion of basal meltwater was evacuated through a channelized subglacial drainage system. Groundwater flow simulation suggests that in areas of very low hydraulic conductivity and adverse subglacial slopes water ponding at the ice sole was likely. In these areas the relief shows distinct palaeo-ice lobes, indicating fast ice flow, possibly triggered by the undrained water at the ice,bed interface. Owing to the abundance of low-permeability strata in the bed, the simulated groundwater flow depth is less than ca. 200 m. Copyright © 2009 John Wiley & Sons, Ltd. [source] PCNA clamp facilitates action of DNA cytosine methyltransferase 1 on hemimethylated DNAGENES TO CELLS, Issue 10 2002Tetsuo Iida Background: Proliferating cell nuclear antigen (PCNA) is a ring-shaped protein known as a processivity factor of DNA polymerase ,. In addition to this role, PCNA interacts with a number of other proteins to increase their local concentration at replicated DNA sites. DNA cytosine methyltransferase 1 (Dnmt1), which preserves epigenetic signals by completing the methylation of hemimethylated DNA after DNA replication, has been indicated as one of these PCNA binding proteins by a previous work. However, the molecular mechanisms and functional significance of their association have not yet been studied. Results: Dnmt1 can be readily isolated from nuclear extracts by PCNA affinity chromatography. Studies of the interactions between the two proteins demonstrate that the N-terminal region of Dnmt1, which contains a typical PCNA binding motif, has core PCNA binding activity, and that the remaining portion of the protein exerts a negative influence on the interaction of Dnmt1 with PCNA. The affinity of Dnmt1 for DNA is much higher for DNA bound by PCNA than for free DNA. Furthermore, DNA methylation assays with hemimethylated DNA as a substrate revealed that PCNA clamp-bound DNA is methylated more efficiently by Dnmt1 than is free DNA. Conclusion: These results provide the first biochemical evidence that physical interactions between PCNA and Dnmt1 facilitate the methylation of newly neplicated DNA, on which PCNA remains associated as a functional clamp. [source] Modified foreskin reconstruction for distal hypospadias and chordee without hypospadiasINTERNATIONAL JOURNAL OF UROLOGY, Issue 7 2008Yutaro Hayashi Abstract: Although foreskin reconstruction was established for hypospadias surgery in Europe two decades ago, it appears to introduce an extra risk of postoperative complications. We modified foreskin reconstruction in order to reduce the complications caused by its use. After correction of penile curvature and urethroplasty, the inner mucosal layer of the foreskin was separated from the outer skin layer. The approximation of each layer in the midline was limited and transverse adaptation was added to the remaining portion. We carried out the modified foreskin reconstruction for 11 patients and no patients developed postoperative complications. After the foreskin reconstruction, the glans, which was concealed by the reconstructed foreskin, was easily exposed by retracting the foreskin. [source] Maternal and fetal microvasculature in sheep placenta at several stages of gestationJOURNAL OF ANATOMY, Issue 3 2010Shireen A. Hafez Abstract Maternal and fetal microvasculature was studied in ewes at days 50, 90 and 130 of gestation using microvascular corrosion casting and scanning electron microscopy. Microvascular corrosion casts of caruncles at day 50 were cup-shaped with a centrally located cavity. Branches of radial arteries entered the caruncle from its base and ramified on the maternal surface of the caruncle. Stem arteries broke into an extensive mesh of capillaries forming crypts on the fetal surface. The architecture of the caruncle at day 90 was similar to what was found at day 50 but the vascularity and the depth of the crypts increased in correspondence to increased branching of fetal villi. The substance of the caruncle was thicker at day 130 compared with day 50, with no remarkable difference compared with day 90. Capillary sinusoids of irregular form and diameter were observed on the fetal surface of the caruncle at all stages. These sinusoids may reduce blood flow resistance and subsequently increase transplacental exchange capacity. A microvascular corrosion cast of the cotyledon was cup-shaped with wide and narrow sides. Cotyledonary vessels entered and left the cotyledon from the narrow side. A cotyledonary artery gave proximal collateral branches immediately after entering the cotyledon and then further branched to supply the remaining portion of the cotyledon. Vessel branches broke into a mesh of capillaries forming the fetal vascular villi. Fetal villi that were nearest to the center of the cotyledon were the longest. Capillaries forming villi were in the form of a web-like mesh, were irregular in size and had sinusoidal dilations. The architecture of the cotyledon at day 90 was similar to day 50, but the vascularity increased. Branching of the fetal villi became more abundant. This extensive branching presumably allows a higher degree of invasion and surface contact to maternal tissues. At day 130, the distal portions of the fetal villi showed low ridges and troughs to increase the surface area for diffusion. Branching of fetal villi appears to influence the elaboration of maternal crypts in all stages of gestation. However, correspondence between crypts and villi is restricted to distal portions of fetal villi. [source] Comparing the antibody responses against recombinant hemagglutinin proteins of avian influenza A (H5N1) virus expressed in insect cells and bacteria,JOURNAL OF MEDICAL VIROLOGY, Issue 11 2008Shuo Shen Abstract The hemagglutinin (HA) of influenza A virus plays an essential role in mediating the entry of the virus into host cells. Here, recombinant full-length HA5 protein from a H5N1 isolate (A/chicken/hatay/2004(H5N1)) was expressed and purified from the baculovirus-insect cell system. As expected, full-length HA5 elicits strong neutralizing antibodies, as evaluated in micro-neutralization tests using HA5 pseudotyped lentiviral particles. In addition, two fragments of HA5 were expressed in bacteria and the N-terminal fragment, covering the ectodomain before the HA1/HA2 polybasic cleavage site, was found to elicit neutralizing antibodies. But the C-terminal fragment, which covers the remaining portion of the ectodomain, did not. Neutralizing titer of the anti-serum against the N-terminal fragment is only four times lower than the anti-serum against the full-length HA5 protein. Using a novel membrane fusion assay, the abilities of these antibodies to block membrane fusion were found to correlate well with the neutralization activities. J. Med. Virol. 80:1972,1983, 2008. © 2008 Wiley-Liss, Inc. [source] Detectable reporter gene expression following transduction of adenovirus and adeno-associated virus serotype 2 vectors within full-thickness osteoarthritic and unaffected canine cartilage in vitro and unaffected guinea pig cartilage in vivoJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2010Kelly S. Santangelo Abstract This study quantified and compared the transduction efficiencies of adenoviral (Ad), Arg-Gly-Asp (RGD)-modified Ad, adeno-associated viral serotype 2 (AAV2), and self-complementary AAV2 (scAAV2) vectors within full-thickness osteoarthritic (OA) and unaffected canine cartilage explants in vitro. Intraarticular administration of Ad and scAAV2 vectors was performed to determine the ability of these vectors to transduce unaffected guinea pig cartilage in vivo. Following explant exposure to vector treatment or control, the onset and surface distribution of reporter gene expression was monitored daily with fluorescent microscopy. At termination, explants were divided: one half was digested for analysis using flow cytometry; the remaining portion was used for histology and immunohistochemistry (IHC). Intact articular joints were collected for real-time RT-PCR and IHC to detect reporter gene expression following injection of selected vectors. Ad vector transduced focal areas along the perimeters of explants; the remaining vectors transduced chondrocytes across 100% of the surface. Greater mean transduction efficiencies were found with both AAV2 vectors as compared to the Ad vector (p,,,0.026). Ad and Ad-RGD vectors transduced only superficial chondrocytes of OA and unaffected cartilage. Uniform reporter gene expression from AAV2 and scAAV2 was detected in the tangential and transitional zones of OA cartilage, but not deeper zones. AAV2 and scAAV2 vectors achieved partial and full-thickness transduction of unaffected cartilage. In vivo work revealed that scAAV2 vector, but not Ad vector, transduced deeper zones of cartilage and menisci. This study demonstrates that AAV2 and scAAV2 are reliable vectors for use in cartilage in vitro and in vivo. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:149,155, 2010 [source] | ||||||||||