Comparison of the outcome of living related donor and cadaveric renal transplantation in Queen Mary Hospital - a single centre experience

Living related donors (LRD) have been the main source of donor kidneys in Hong Kong. In recent years, there has been an increase in the proportion of cadaveric (CAD) kidneys transplantation. This review examines the results of renal transplantation in. Queen Mary Hospital (QMH) in order to assess the continuing need for LRD kidney transplantation. The records of 159 of 165 transplant cases between 1983 and 1991 were analyzed. The mean age of recipients was 35.6 years (range 11 to 57), with a male predominance in the LED recipients (p = 0.03). The waiting time for the LRD recipients was significantly less than the CAD recipients (p < 0.001). There was no difference in the distribution of different primary renal diseases causing end stage renal failure between the LRD and CAD groups. The cumulative graft survival at five years was 82.5% and 65.8% for LRD and CAD respectively (p = 0.02), Graft function was also significantly better in LRD recipients (p < 0,01), Early surgical complications were more common after CAD transplantation (14% vs 29%, p = 0.02). While the transplant centres and the Hong Kong Government continue to promote cadaveric organ donation, the LRD transplant programme should be equally encouraged because of superior graft outcome.published_or_final_versio

AI is a viable alternative to high throughput screening: a 318-target study

: High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery

Analysis of the sacral neural crest cell contribution to the hindgut enteric nervous system in the mouse embryo

Background & Aims: The majority of the enteric nervous system is derived from the vagal neural crest, with a second contribution, which is restricted to the post-umbilical gut, originating from the sacral neural crest. In mammals, although sacral neural crest cells (NCCs) have been shown to enter the hindgut, information on their development and role remains scant. Our aim was to determine the migratory routes of sacral NCCs to the hindgut, their timing and site of entry into the gut, and their migratory behaviors and differentiation within the hindgut. Methods: We used in situ cell labeling, whole embryo culture, immunofluorescence, organotypic culture, and time-lapse live-cell imaging in mouse embryos. Results: Sacral NCCs emigrated from the neural tube at embryonic day 9.5, accumulated bilateral to the hindgut to form prospective pelvic ganglia at embryonic day 11.5, and from there entered the distal hindgut through its ventrolateral side at embryonic day 13.5. They then migrated along nerve fibers extending from the pelvic ganglia toward the proximal hindgut, intermingling with rostrocaudally migrating vagal NCCs to differentiate into neurons and glia. In organotypic culture, genetically labeled sacral and vagal NCCs displayed different capabilities of entering the hindgut, implying differences in their intrinsic migratory properties. Time-lapse live-cell imaging on explants ex vivo showed that sacral NCCs migrated along nerve fibers and exhibited different migratory behaviors from vagal NCCs. Conclusions: Murine sacral NCCs are a distinct group of cells that migrate along defined pathways from neural tube to hindgut. They exhibit discrete migratory behaviors within the gut mesenchyme and contribute neurons and glial cells to the hindgut enteric nervous system. © 2011 AGA Institute.link_to_subscribed_fulltex

The Design and Tests of Metal Scaffolding Used in Slopeworks

Invited conference paperDepartment of Building and Real Estat

A novel role of cdc-family gene PFTK1 in the control of liver cancer cell motility

Poster Session 17 - Signaling in Tumor Cell Migration and Invasion 2: abstract no. 5297Cancer metastasis remains a major cause of cancer morbidity and mortality in individuals diagnosed with hepatocellular carcinoma (HCC). We previously reported on regional chromosome 7q21-q22 gains in close association with HCC progression, and discerned a candidate proto-oncogene PFTK1 within this region by array-based CGH mapping. The PFTK1 protein, PFTAIRE protein kinase 1, is a novel member of the Cdc2-related serine/threonine protein kinases. Our earlier investigations by ectopic expression and gene knockdown of PFTK1 confirmed a functional role for the PFTAIRE protein kinase in the motile phenotype of HCC cells, yet the biological basis remained to be determined. The aims of this study are therefore to establish the clinicopathologic significance of PFTK1 in HCC, and to define the PFTK1-modulated mechanisms in the control of HCC cell motility. Recent Tissue Microarray Analysis (TMA) on 180 paired primary HCC and their adjacent non-tumoral liver suggested common up-regulated PFTK1 compared to non-malignant counterpart (76.1%; p<0.0001). Correlative analysis further indicated PFTK1 over-expression in association with advanced tumor grading (P<0.0001) and the presence of microvascular invasion (P=0.05). By 2D-PAGE coupled with mass spectrometry, comparative proteomic profiling for phosphorylated proteins in PFTK1-suppressed HCC cells highlighted 5 differentially down-regulated spots, which included β-actin (ACTB), transgelin2 (TAGLN2), heat shock protein 70, mitochondrial aldehyde dehydrogenase and 14-3-3 gamma protein. Western blot analysis further verified a consistent reduction on ACTB phosphorylation and the serine phosphorylation of the TAGLN2 protein in the absence of PFTK1 protein kinase. Immunofluorescence analysis for cytoskeletal organizations indicated marked reduction on the actin stress fibers in PFTK1 knockdown cells. In conclusion, our results suggested that PFTK1 can affect the actin cytoskeletal organization and thus a motile phenotype in HCC cells through phosphorylation of ACTB and TAGLN2.link_to_OA_fulltextThe 101st Annual Meeting of the American Association for Cancer Research (AACR 2010), Washington D.C., 17-21 April 2010. In AACR Meeting Abstracts, 201

A novel interplay between oncogenic PFTK1 protein kinase and tumor suppressor TAGLN2 in the control of liver cancer cell motility

The PFTK1 gene encodes a cdc2-related serine/threonine protein kinase that has been shown to confer cell migratory properties in hepatocellular carcinoma (HCC). However, the prognostic value and biological mechanism by which PFTK1 promotes HCC motility remain largely unknown. Here, we showed from tissue microarray that common upregulations of PFTK1 in primary HCC tumors (n133/180) correlated significantly with early age onset (≤40 years), advance tumor grading and presence of microvascular invasion (≤P0.05). To understand downstream phosphorylated substrate(s) of PFTK1, phospho-proteins in PFTK1 expressing and knockdown Hep3B cells were profiled by two-dimensional- polyacrylamide gel electrophoresis mass spectrometric analysis. Protein identification of differential spots revealed Β-actin (ACTB) and transgelin2 (TAGLN2) as the two most profound phosphorylated changes affected by PFTK1. We verified the presence of TAGLN2 serine phosphorylation and ACTB tyrosine phosphorylation. Moreover, reduced TAGLN2 and ACTB phosphorylations in PFTK1-suppressed Hep3B corresponded to distinct actin depolymerizations and marked inhibition on cell invasion and motility. Given that TAGLN2 is a tumor suppressor whose function has been ascribed in cancer metastasis, we examined if TAGLN2 is an intermediate substrate in the biological path of PFTK1. We showed in PFTK1-suppressed cells that knockdown of TAGLN2 over-rode the inhibitory effect on cell invasion and motility, and a recovery on actin polymerization was evident. Interestingly, we also found that unphosphorylated TAGLN2 in PFTK1-suppressed cells elicited strong actin-binding ability, a mechanism that possibly halts the actin cytoskeleton dynamics. Site-directed mutagenesis of TAGLN2 suggested that PFTK1 regulates the actin-binding affinity of TAGLN2 through the S83 and S163 residues, which if mutated can significantly affect HCC cell motility. Taken together, our data propose a novel, oncogene-tumor suppressor interplay, where oncogenic PFTK1 confers HCC cell motility through inactivating the actin-binding motile suppressing function of TAGLN2 via phosphorylation. © 2011 Macmillan Publishers Limited All rights reserved.link_to_subscribed_fulltex

Disruption of T cell signaling networks and development by Grb2 haploid insufficiency

The developmental processes of positive and negative selection in the thymus shape the T cell antigen receptor (TCR) repertoire and require the integration of multiple signaling networks. These networks involve the efficient assembly of macromolecular complexes and are mediated by multimodular adaptor proteins that permit the functional integration of distinct signaling molecules. We show here that decreased expression of the adaptor protein Grb2 in Grb2 +/- mice weakens TCR-induced c-Jun N-terminal kinase (JNK) and p38, but not extracellular signal−regulated kinase (ERK), activation. In turn, this selective effect decreases the ability of thymocytes to undergo negative, but not positive, selection. We also show that there are differences in the signaling thresholds of the three mitogen-activated protein kinase (MAPK) families. These differences may provide a mechanism by which quantitative differences in signal strength can alter the balance of downstream signaling pathways to induce the qualitatively distinct biological outcomes of proliferation, differentiation or apoptosis

Expression of a cyclo-oxygenase-2 transgene in murine liver causes hepatitis

Background: It has been proved that cyclo-oxygenase-2 (COX-2) is rapidly induced by inflammatory mediators. However, it is not known whether overexpression of COX-2 in the liver is sufficient to promote activation or secretion of inflammatory factors leading to hepatitis. Aim: To investigate the role forced expression of COX-2 in liver by using inducible COX-2 transgenic (TG) mice. Methods: TG mice that overexpress the human COX-2 gene in the liver using the liver-specific transthyretin promoter and non-TG littermates were derived and fed the normal diet for up to 12 months. Hepatic prostaglandin E 2 (PGE 2) content was determined using enzyme immunoassay, nuclear factor kappaB (NF-κB) activation by electrophoretic mobility shift assays, apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labelling and proliferation by Ki-67 immunohistochemistry. Results: COX-2 TG mice exhibited strongly increased COX-2 and PGE 2, elevated serum alanine aminotransferase level and histological hepatitis. Hepatic COX-2 expression in the TG mice resulted in activation of NF-κB and inflammatory cytokine cascade, with a marked expression of the proinflammatory cytokines tumour necrosis factor (TNF)-α (9.4-fold), interleukin (IL)-6 (4.4-fold), IL-1β (3.6-fold), and of the anti-inflammatory cytokine IL-10 (4.4-fold) and chemokine macrophage inflammatory protein-2 (3.2-fold). The inflammatory response of the COX-2 TG mice was associated with infiltration macrophages and lymphocytes, increased cell proliferation and high rates of cell apoptosis. Administration of the COX-2 inhibitor celecoxib in TG mice restored liver histology to normal. Conclusion: Enhanced COX-2 expression in hepatocytes is sufficient to induce hepatitis by activating NF-κB, stimulating the secretion of proinflammatory cytokines, recruiting macrophage and altering cell kinetics. Inhibition of COX-2 represents a mechanism-based chemopreventive approach to hepatitis.link_to_subscribed_fulltex