76
|
Chen Y, Liu Y, Yuan Z, Tian L, Dallman MJ, Thompson PW, Tam PKH, Lamb JR. Rosiglitazone Suppresses Cyclosporin-Induced Chronic Transplant Dysfunction and Prolongs Survival of Rat Cardiac Allografts. Transplantation 2007; 83:1602-10. [PMID: 17589344 DOI: 10.1097/01.tp.0000266994.39480.42] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The lack of effective treatment for chronic transplant dysfunction restricts the long-term survival of solid organ allografts. Peroxisome proliferator-activated receptor ligands can suppress vascular inflammation. The aim of this study was to analyze the effects of rosiglitazone on chronic transplant dysfunction in a rat cardiac transplant model. METHODS Inbred male Fisher 344 (F344, RT1lvl) and Lewis (LEW, RT1(1)) rats were subjected to heterotopic abdominal heart transplantation according to standard procedures. Cyclosporine A was administered intraperitoneally to cover acute rejection, and rosiglitazone was administered orally by gavage daily from 3 days before the operation to the end of experiments. RESULTS Rosiglitazone significantly prolonged the survival of cardiac allografts in rats (F344 to LEW) that had received a 10-day course of cyclosporin A compared to treatment with immunosuppressant alone. Analysis of allografts at 120 days posttransplantation showed that rosiglitazone reduced the inflammatory cell infiltrate in both the vessels and graft parenchyma as were neointimal formation, vascular occlusion, and fibrosis. Expression of transforming growth factor-beta and related proteins was less abundant after cyclosporin A/rosiglitazone treatment. CONCLUSIONS The findings reported here demonstrate that rosiglitazone given under the cover of short-term treatment with cyclosporin A prolongs cardiac allograft survival and reduces the severity of chronic transplant dysfunction. This may be mediated in part through the downregulation of transforming growth factor-beta and related proteins. The combined effects of rosiglitazone and immunosuppressive drugs are potentially beneficial to patients receiving organ transplants.
Collapse
|
77
|
Chen Y, Li X, Tian L, Lui VCH, Dallman MJ, Lamb JR, Tam PKH. Inhibition of Sonic Hedgehog Signaling Reduces Chronic Rejection and Prolongs Allograft Survival in a Rat Orthotopic Small Bowel Transplantation Model. Transplantation 2007; 83:1351-7. [PMID: 17519786 DOI: 10.1097/01.tp.0000262568.73590.81] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Although acute graft rejection can be successfully controlled by immunosuppressive agents, chronic rejection (CR), which is characterized by arteriosclerosis in the donor organ vessels, is a major hurdle to long-term allograft survival. Sonic hedgehog (Shh), a morphogen critical in embryogenesis, also promotes peripheral immunity, which prompted us to investigate if inhibition of Shh signaling could reduce CR and thereby enhance allograft survival. METHODS In a rat orthotopic small bowel transplantation model, FK506 prevented acute rejection; however, recipients eventually lost their grafts by CR. Anti-Shh antibody or isotype control were administered to animals at day 30 postoperatively. Graft survival, tissue fibrosis, vascular occlusion, and expression of vascular endothelial growth factor (VEGF) were investigated. RESULTS Immunostaining revealed that Shh and the Hedgehog receptor Patched 1 (Ptc1) are strongly expressed in CR grafts and that Ptc1 expression partially overlapped with that of ED-1, a macrophage marker. In contrast, only minimal expression of Shh and Ptc1 was detected in syngeneic grafts. Grafts survival was significantly prolonged after anti-Shh antibody treatment compared with the immunoglobulin G control (116 vs. 77.5 days). Collagen deposition and vascular occlusion in the mesentery were markedly reduced in recipients of the anti-Shh antibody. Specific transcripts and protein expression for VEGF, which was present mainly in the blood vessels, were reduced. CONCLUSION In a rat small bowel transplantation model, anti-Shh antibody treatment reduced CR and prolonged graft survival. These beneficial effects of Shh treatment may occur partly by reducing VEGF expression in the blood vessels of the allografts.
Collapse
|
78
|
Ngan ESW, Sit FYL, Lee K, Miao X, Yuan Z, Wang W, Nicholls JM, Wong KKY, Garcia-Barcelo M, Lui VCH, Tam PKH. Implications of endocrine gland-derived vascular endothelial growth factor/prokineticin-1 signaling in human neuroblastoma progression. Clin Cancer Res 2007; 13:868-75. [PMID: 17289879 DOI: 10.1158/1078-0432.ccr-06-2176] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Neuroblastoma is a common pediatric tumor that is derived from improperly differentiated neural crest cells (NCC). We recently revealed that endocrine gland-derived vascular endothelial growth factor/prokineticin-1 (EG-VEGF/Prok-1) is a key factor mediating the growth and differentiation of enteric NCCs during development. In this report, we further elucidate its role in neuroblastoma progression. EXPERIMENTAL DESIGN We studied the expression and copy number of EG-VEGF/Prok-1 receptors (PK-R1 and PK-R2) in 26 neuroblastoma tumors by real-time reverse transcription-PCR and immunohistochemical analysis. Implication of EG-VEGF/Prok-1 signaling in neuroblastoma progression was further shown in a neuroblastoma cell line (SK-N-SH). RESULTS We found that all neuroblastoma samples from stages II to IV expressed both PK-R1 and PK-R2. Kruskall-Wallis signed rank tests revealed that the expression level of PK-R1 transcript is associated with the stages and metastasis of the neuroblastoma (P<0.05), and PK-R2 is persistently higher in advanced-stage neuroblastoma samples. About 38% of the neuroblastoma tumors (10:26) possessed MYCN amplification, whereas no PK-R1 and PK-R2 amplifications were detected, suggesting that the overexpression of the receptors was not due to gene amplification. Subsequent functional studies showed that EG-VEGF/Prok-1 activates the Akt pathway to induce the proliferation of neuroblastoma cells. Targeted down-regulation studies revealed that EG-VEGF/Prok-1-mediated proliferation requires the presence of these two receptors, and that PK-R2 is essential for inhibiting apoptosis. In vitro migration and invasion assays also indicated that EG-VEGF/Prok-1 significantly enhances the cell migration/invasion of SK-N-SH. CONCLUSIONS Our study has shown for the first time that aberrant EG-VEGF/Prok-1 signaling favors neuroblastoma progression and could be a potential target for future neuroblastoma treatment.
Collapse
|
79
|
Garcia-Barcelo M, King SK, Miao X, So MT, Holden WT, Moore JH, Sutcliffe JR, Hutson JM, Tam PKH. Application of HapMap data to the evaluation of 8 candidate genes for pediatric slow transit constipation. J Pediatr Surg 2007; 42:666-71. [PMID: 17448763 DOI: 10.1016/j.jpedsurg.2006.12.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
BACKGROUND Slow transit constipation (STC) affects up to 3% of all children and is an increasingly recognized cause of chronic constipation in children. We conducted a pilot study to investigate whether genes encoding neurotransmitters (TAC1, TAC3, VIP, NOS1) and receptors (TACR1, TACR2, TACR3, KIT) could be responsible for STC. METHODS One hundred seventeen tag single nucleotide polymorphisms (SNPs), distributed among the candidate genes, were selected from HapMap data and genotyped using Sequenom (San Diego, CA) technology in 35 affected families. Evaluation of association was performed by transmission disequilibrium test and multilocus analysis. RESULTS Five SNPs (rs3771863, rs4580655, rs11722288, rs4563545, and rs3782221) in the TACR1, TACR3, KIT, and NOS1 genes were found to be potentially associated with STC, although the significance of these results does not withstand correction for multiple testing. CONCLUSIONS Our data indicate that 5 SNPs in the NOS1, TACR1, TACR3, and KIT genes could be involved in STC, especially rs3771863 in intron 1 of TACR1, which showed the highest association.
Collapse
|
80
|
Ngan ESW, Lee KY, Sit FYL, Poon HC, Chan JKY, Sham MH, Lui VCH, Tam PKH. Prokineticin-1 modulates proliferation and differentiation of enteric neural crest cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:536-45. [PMID: 17324478 DOI: 10.1016/j.bbamcr.2007.01.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Revised: 01/23/2007] [Accepted: 01/24/2007] [Indexed: 12/12/2022]
Abstract
Prokineticins (Prok-1 and Prok-2) belong to a newly identified AVIT protein family. They are involved in variety of activities in various tissues, including smooth muscle contraction of the gastrointestinal tract and promoting proliferation of endothelial cells derived from adrenal gland. Importantly, they also act as the survival factors to modulate growth and survival of neurons and hematopoietic stem cells. In this study we demonstrated that Prok-1 (but not Prok-2) protein is expressed in the mucosa and mesenchyme of the mouse embryonic gut during enteric nervous system development. Its receptor, PK-R1 is expressed in the enteric neural crest cells (NCCs). To elucidate the physiological role(s) of Prok-1 in NCCs, we isolated the NCCs from the mouse embryonic gut (E11.5) and cultured them in the form of neurospheres. In an in vitro NCC culture, Prok-1 was able to activate both Akt and MAPK pathways and induce the proliferation and differentiation (but not migration) of NCCs via PK-R1. Knock-down of PK-R1 using siRNA resulted in a complete abolishment of Prok-1 induced proliferation. Taken together, it is the first report demonstrating that Prok-1 acts as a gut mucosa/mesenchyme-derived factor and maintains proliferation and differentiation of enteric NCCs.
Collapse
|
81
|
Garcia-Barceló MM, Miao X, Lui VCH, So MT, Ngan ESW, Leon TYY, Lau DKC, Liu TT, Lao X, Guo W, Holden WT, Moore J, Tam PKH. Correlation between genetic variations in Hox clusters and Hirschsprung's disease. Ann Hum Genet 2007; 71:526-36. [PMID: 17274802 DOI: 10.1111/j.1469-1809.2007.00347.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Interactions between migrating neural crest cells and the environment of the gut are crucial for the development of the enteric nervous system (ENS). A key signalling mediator is the RET-receptor-tyrosine-kinase which, when defective, causes Hirschprung's disease (HSCR, colon aganglionosis). RET mutations alone cannot account for the variable HSCR phenotype, invoking interactions with as yet unknown, and probably inter-related, loci involved in ENS development. Homeobox (HOX) genes have a major role in gut development as depicted by the enteric Hox code. We investigated whether DNA alterations in HOX genes, either alone or in combination with RET, are implicated in HSCR. Genotyping effort was minimized by applying the HapMap data on Han Chinese from Beijing (CHB). 194 HSCR patients and 168 controls were genotyped using Sequenom technology for 72 tag, single nucleotide polymorphisms (SNPs) distributed along the HOX clusters. The HapMap frequencies were compared to those in our population and standard statistics were used for frequency comparisons. The multifactor-dimensionality-reduction method was used for multilocus analysis, in which RET promoter SNP genotypes were included. Genetic interactions were found between two HOX loci (5'-HOXA13 and 3'UTR-HOXB7) and the RET loci tested. Minor allele frequencies (MAF) of the SNPs tested in our sample were not significantly different from those reported by HapMap when the sample sizes of the populations compared were considered. This is the first evaluation of the HOX genes in HSCR and the first application of HapMap data in a Chinese population. The interacting HOX loci may affect the penetrance of the RET risk allele. HapMap data for the CHB population correlated well with the general Chinese population.
Collapse
|
82
|
Xie Y, Chan H, Fan J, Chen Y, Young J, Li W, Miao X, Yuan Z, Wang H, Tam PKH, Ren Y. Involvement of visinin-like protein-1 (VSNL-1) in regulating proliferative and invasive properties of neuroblastoma. Carcinogenesis 2007; 28:2122-30. [PMID: 17615261 DOI: 10.1093/carcin/bgm147] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Tumor growth and metastasis require that tumor cells must have either the potential to shift genetically or epigenetically between proliferative and invasive phenotypes or both phenotypes simultaneously. In the present study, we demonstrated that neuroblastoma growth and invasion were distinct processes that were carried out by proliferative and invasive phenotypes of tumor cells, respectively. Two subpopulations from human neuroblastoma cell line were isolated: highly invasive (HI) cells and low-invasive (LI) cells. HI and LI cells had different proliferative rate and metastatic ability in vitro and in vivo. In addition, they had distinct activated signal pathways and sensitivities to chemotherapy drugs. Affymetrix microarray and quantitative reverse transcriptase-polymerase chain reaction revealed that visinin-like protein-1 (VSNL-1) mRNA in HI cells was significantly higher than that in LI cells. We also observed that VSNL-1 was over-expressed in tumor specimens from patients with distant organ metastases compared with those without metastases. Furthermore, the invasive and proliferative phenotypes of neuroblastoma cells could be exchanged by regulation of VSNL-1 expression in vitro and in vivo. Up-regulation of VSNL-1 potentiated the anoikis-resistant ability of neuroblastoma cell. The expression of anoikis inhibitor TrkB, intracellular adhesion molecule 1, major histocompatibility complex class I, CD44 and CD44v6 was associated with VSNL-1 level. These results suggested that distinct roles of proliferative and invasive phenotypes contributed to neuroblastoma progression and strongly demonstrated that VSNL-1 played a very important role in neuroblastoma metastasis.
Collapse
|
83
|
Tian J, Wong KKY, Ho CM, Lok CN, Yu WY, Che CM, Chiu JF, Tam PKH. Topical Delivery of Silver Nanoparticles Promotes Wound Healing. ChemMedChem 2007; 2:129-36. [PMID: 17075952 DOI: 10.1002/cmdc.200600171] [Citation(s) in RCA: 527] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Wound healing is a complex process and has been the subject of intense research for a long time. The recent emergence of nanotechnology has provided a new therapeutic modality in silver nanoparticles for use in burn wounds. Nonetheless, the beneficial effects of silver nanoparticles on wound healing remain unknown. We investigated the wound-healing properties of silver nanoparticles in an animal model and found that rapid healing and improved cosmetic appearance occur in a dose-dependent manner. Furthermore, through quantitative PCR, immunohistochemistry, and proteomic studies, we showed that silver nanoparticles exert positive effects through their antimicrobial properties, reduction in wound inflammation, and modulation of fibrogenic cytokines. These results have given insight into the actions of silver and have provided a novel therapeutic direction for wound treatment in clinical practice.
Collapse
|
84
|
Abstract
Pneumoperitoneum is considered to be a surgical emergency as it nearly always indicates a perforated abdominal viscus. However, in rare cases, the presence of 'free gas under diaphragm' may not imply the need for emergent laparotomy, as pneumoperitoneum can occur without any gastrointestinal leakage. Here we report a rare case of a previously healthy boy with pneumoperitoneum associated with pneumonia and perform a review of the literature to explore the etiological mechanisms and the pathophysiology of non-surgical pneumoperitoneum.
Collapse
|
85
|
Wong KKY, Fang CX, Tam PKH. Selective upper endoscopy for foreign body ingestion in children: an evaluation of management protocol after 282 cases. J Pediatr Surg 2006; 41:2016-8. [PMID: 17161195 DOI: 10.1016/j.jpedsurg.2006.08.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE Foreign body ingestion is a common problem in both children and adults. This study aims to evaluate a management protocol where endoscopic examination was only selectively used after routine direct laryngoscopy to minimize patient discomfort and the need for general anesthesia in children. METHOD A management protocol for foreign body ingestion based on symptoms was introduced in 1998 and records of children admitted to a university-affiliated hospital between January 1999 and October 2005 with suspected foreign body ingestion were evaluated. Symptoms, radiologic and endoscopic findings, and outcome were reviewed. RESULTS A total of 282 patients were admitted. The mean age of patients was 5.75 years (range, 9 months to 17 years). There were 167 boys and 115 girls. Based on our protocol, 84 (29.8%) patients required an upper endoscopy. Fish bones were most commonly involved (68.8%). Foreign bodies, which were either removed or dislodged, were found during upper endoscopy in only 25 (8.8%) patients overall. All patients had an uneventful outcome. No complications or mortalities were encountered. There were no readmissions for those who did not undergo endoscopic examination. CONCLUSION It is safe to selectively perform upper endoscopy depending on symptoms when managing children with foreign body ingestion.
Collapse
|
86
|
Ren Y, Chan HM, Xie Y, Chen YX, Li W, Jiang GP, Liu Q, Meinhardt A, Tam PKH. Erratum: Inhibition of tumor growth and metastasis in vitro and in vivo by targeting macrophage migration inhibitory factor in human neuroblastomas. Oncogene 2006. [DOI: 10.1038/sj.onc.1210005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
87
|
Chan VSF, Chau SY, Tian L, Chen Y, Kwong SKY, Quackenbush J, Dallman M, Lamb J, Tam PKH. Sonic hedgehog promotes CD4+ T lymphocyte proliferation and modulates the expression of a subset of CD28-targeted genes. Int Immunol 2006; 18:1627-36. [PMID: 17005629 DOI: 10.1093/intimm/dxl096] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sonic hedgehog (Shh) is a crucial morphogen in the development of numerous tissues and organs, including the nervous system, gastrointestinal tract and lung. Recent findings suggest that Shh plays an important role in thymocyte development and peripheral T cell function. Here we report that the Shh receptors, patched and smoothened, are expressed in resting and activated T cells and their expression is regulated upon T cell activation. Shh protein is also detected on the surface of freshly isolated T cells. Although exogenous Shh alone does not activate resting T cells, it exhibits co-stimulatory activity which is reflected in its ability to potentiate CD3-mediated proliferation and cytokine production by CD4(+) T cells. The co-stimulatory effect is most prominent at sub-optimal TCR stimulation level. Gene expression analysis reveals that Shh signaling in CD4(+) T cells modulates a different set of transcriptional targets from that in neuronal cells. Furthermore, Shh co-stimulation modulates the expression of a subset of CD28-responsive genes, including cyclin A and B cell translocation gene 2.
Collapse
|
88
|
Chan KL, Tang MHY, Tse HY, Tang RYK, Tam PKH. Meconium peritonitis: prenatal diagnosis, postnatal management and outcome. Prenat Diagn 2006; 25:676-82. [PMID: 16049997 DOI: 10.1002/pd.1221] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVES Prenatal ultrasonography (USS) is a routine screening test for fetal abnormalities. Its accuracy for detecting meconium peritonitis (MP), which may carry high mortality, is important for prenatal counseling. The aim of this study was to assess the accuracy of prenatal USS for diagnosing MP and predicting patient outcomes. METHODS The prenatal and postnatal medical records of all patients referred to our institutions with confirmed MP were reviewed, with emphasis on prenatal USS findings, results of postnatal investigations, operative findings, outcomes, and possible causes of MP. RESULTS From January 2000 to November 2004, seven fetuses were confirmed to have MP at birth. Three MP patients (3/7, 43%) were diagnosed prenatally because of USS showing ascites and calcification/dilated or hyperechoic bowel loops. One (1/7, 14.3%) suspected cystic MP was confirmed by prenatal MRI. In the other three cases, USS showed only ascites. All patients had postnatal contrast CT scans. Two patients' CT scans showed persistent intestinal perforation not visible with prenatal USS, and required emergency operations. All patients survived and prospered, and were sweat test negative. CONCLUSIONS Prenatal USS allows suspected MP babies to be transferred to a tertiary centre for delivery and appropriate management. In this way, the chances of survival of these babies can be excellent if they are not associated with cystic fibrosis (CF). Prenatal MRI can improve the low diagnostic yield of prenatal USS for MP. Postnatal contrast CT scan is required to define persistent intestinal perforation invisible with prenatal USS.
Collapse
|
89
|
Yip KF, Tam PKH, Li MKW. A Simple and Secure Method to Fix Laparoscopic Trocars in Children. J Laparoendosc Adv Surg Tech A 2006; 16:188-90. [PMID: 16646715 DOI: 10.1089/lap.2006.16.188] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We introduce a simple method of fixing trocars to the abdominal wall in children. Before anchoring the trocar, a piece of Tegaderm polyurethrane adhesive (3M Healthcare, St. Paul, Minnesota) is attached to the trocar. A silk stitch is anchored to neighboring skin, and then transfixed over the shaft of the trocar through the adhesive. Both inward and outward movement of the trocar can be restrained. This method is simple, fast, secure, and can be applied to trocars of any size.
Collapse
|
90
|
Ren Y, Chan HM, Fan J, Xie Y, Chen YX, Li W, Jiang GP, Liu Q, Meinhardt A, Tam PKH. Inhibition of tumor growth and metastasis in vitro and in vivo by targeting macrophage migration inhibitory factor in human neuroblastoma. Oncogene 2006; 25:3501-8. [PMID: 16449971 DOI: 10.1038/sj.onc.1209395] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Macrophage migration inhibitory factor (MIF) has been defined as a novel oncogene. Our previous results have shown that MIF may contribute to the progression of neuroblastoma by (a) inducing N-Myc expression and (b) upregulating the expression of angiogenic factors. The aim of this study was to test whether tumor growth could be inhibited by reduction of endogenous MIF expression in neuroblastoma and clarify the molecular mechanisms underlying MIF reduction on the control of neuroblastoma growth. We established human neuroblastoma cell lines stably expressing antisense MIF (AS-MIF) cDNA. These stable transfectants were characterized by cell proliferation, gene expression profile, tumorigenicity and metastasis in vitro and in vivo. Decreased MIF expression was observed after transfection with AS-MIF in neuroblastoma cells and downregulation of MIF expression significantly correlated with decreased expression of N-Myc, Ras, c-Met and TrkB at protein level. Affymetrix microarray analysis revealed that expression of IL-8 and c-met was inhibited and neuroblastoma-favorable genes such as EPHB6 and BLU were upregulated in MIF reduced cells. Neuroblastoma cell growth exhibited a nearly 80% reduction in AS-MIF transfectants in vitro. Furthermore, mice in which tumors formed after subcutaneous injection of AS-MIF transfectants showed a 90% reduction in tumor growth compared to control. Metastasis in mice was also suppressed dramatically. Our data demonstrate that targeting MIF expression is a promising therapeutic strategy in human neuroblastoma therapy, and also identifies the MIF target genes for further study.
Collapse
|
91
|
Chan VSF, Chan KYK, Chen Y, Poon LLM, Cheung ANY, Zheng B, Chan KH, Mak W, Ngan HYS, Xu X, Screaton G, Tam PKH, Austyn JM, Chan LC, Yip SP, Peiris M, Khoo US, Lin CLS. Homozygous L-SIGN (CLEC4M) plays a protective role in SARS coronavirus infection. Nat Genet 2006; 38:38-46. [PMID: 16369534 PMCID: PMC7097088 DOI: 10.1038/ng1698] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Accepted: 10/03/2005] [Indexed: 12/22/2022]
Abstract
Severe acute respiratory syndrome (SARS) is caused by infection of a previously undescribed coronavirus (CoV). L-SIGN, encoded by CLEC4M (also known as CD209L), is a SARS-CoV binding receptor that has polymorphism in its extracellular neck region encoded by the tandem repeat domain in exon 4. Our genetic risk association study shows that individuals homozygous for CLEC4M tandem repeats are less susceptible to SARS infection. L-SIGN is expressed in both non-SARS and SARS-CoV-infected lung. Compared with cells heterozygous for L-SIGN, cells homozygous for L-SIGN show higher binding capacity for SARS-CoV, higher proteasome-dependent viral degradation and a lower capacity for trans infection. Thus, homozygosity for L-SIGN plays a protective role during SARS infection.
Collapse
|
92
|
Wong KKY, Chung PHY, Lan LCL, Lin SCL, Tam PKH. Trends in the prevalence of Helicobacter pylori in symptomatic children in the era of eradication. J Pediatr Surg 2005; 40:1844-7. [PMID: 16338302 DOI: 10.1016/j.jpedsurg.2005.08.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE Helicobacter pylori infection is common in Asia and is associated with dyspepsia, peptic ulcer, and gastric cancer. Eradication of the organism remains an important goal. Here, we looked at the trends in the prevalence of H pylori in symptomatic children over an 8-year period to assess the impact of an aggressive eradication program. METHOD A retrospective review was carried out between 1997 and 2004. All children with a history of dyspepsia or acute gastrointestinal bleeding were included and underwent gastroscopy. Three antral biopsies were taken during endoscopy and sent for histological analysis. Positivity of H pylori was treated aggressively with quadruple therapy under protocol. The demographic data, the histological findings, and the H pylori status were recorded. RESULTS There were a total of 159 patients (71 males, 88 females) who underwent gastroscopy in this period. One hundred nineteen patients showed histological evidence of gastritis, and the positive rate of H pylori was 25.6%. The overall prevalence has not decreased (33.3% in 1997, 27.7% in 2004). Increasing age, however, was associated significantly with the higher risk of H pylori infection. CONCLUSION H pylori has a high prevalence in Chinese children with increasing age. Eradication efforts seem to be unsuccessful in the reduction of prevalence. We hypothesize that this may be owing to cross-infection at meal times from sharing chopsticks.
Collapse
|
93
|
Fan J, Chen Y, Chan HM, Tam PKH, Ren Y. Removing intensity effects and identifying significant genes for Affymetrix arrays in macrophage migration inhibitory factor-suppressed neuroblastoma cells. Proc Natl Acad Sci U S A 2005; 102:17751-6. [PMID: 16314559 PMCID: PMC1308934 DOI: 10.1073/pnas.0509175102] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A semilinear in-slide model is introduced to remove the intensity effect in the scanning process. It is demonstrated that the intensity effect can be estimated accurately and removed effectively. This normalization step is vital for Affymetrix arrays to reveal relevant biological results when comparing gene expression in multiple arrays. The normalized expression ratios are analyzed further by a modified two-sample t test along with a sieved permutation scheme for computing P values. The improved specificity and sensitivity are demonstrated by using a study on the impact of macrophage migration inhibitory factor (MIF) reduction in neuroblastoma cells. With semilinear in-slide model analysis, expression of 166 genes was altered with a P value no greater than 0.001. Among those genes, 44 were altered >2-fold. MIF-regulated genes associated with tumor development including IL-8 and C-met, which are overexpressed in many tumors, were down-regulated in MIF-reduced cells. On the other hand, some tumor-suppressor genes such as EPHB6, visinin-like protein 1 (VSNL-1), and BLU were up-regulated in MIF-reduced cells. In addition, we demonstrated that down-regulation of MIF expression could result in a reduction in cell proliferation and tumor growth in vitro and in vivo. Our data not only demonstrate that targeting MIF expression is a promising therapeutic strategy in human neuroblastoma therapy but also indicate the MIF target genes for additional study.
Collapse
|
94
|
Lui VCH, Leon TYY, Garcia-Barceló MM, Ganster RW, Chen BLS, Hutson JM, Tam PKH. Novel RET mutation produces a truncated RET receptor lacking the intracellular signaling domain in a 3-generation family with Hirschsprung disease. Clin Chem 2005; 51:1552-4. [PMID: 16040858 DOI: 10.1373/clinchem.2005.051904] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
95
|
He QY, Zhu R, Ren Y, Tam PKH, Chiu JF. Serological protein profiling of neuroblastoma by ProteinChip SELDI-TOF technology. J Cell Biochem 2005; 95:165-72. [PMID: 15759280 DOI: 10.1002/jcb.20417] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Serological proteins of neuroblastoma were profiled and analyzed by ProteinChip-SELDI-TOF MS technology with five types of protein chips. By comparing with normal control, a number of protein or polypeptide signals were found significantly and consistently different in their intensities (expression levels) in tumor sera. Interestingly, nine polypeptide peaks in these proteomic features can be simultaneously detected with consistent variations by more than one type of protein chips. None of the expression differences of these nine polypeptides was found in similar comparisons between healthy controls and hepatomas. Preliminary protein identification showed hints for that some of these proteomic alterations may be closely related to the tumorigenesis of neuroblastoma. These results demonstrated the potential of serological biomarker identification for neuroblastoma by ProteinChip-SELDI technology.
Collapse
|
96
|
Ren Y, Lin CL, Li Z, Chen XY, Huang X, Lui V, Nicholls J, Lan HY, Tam PKH. Up-regulation of macrophage migration inhibitory factor in infants with acute neonatal necrotizing enterocolitis. Histopathology 2005; 46:659-67. [PMID: 15910597 DOI: 10.1111/j.1365-2559.2005.02159.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS To investigate the role of macrophage migration inhibitory factor (MIF) and its downstream cytokine cascade in necrotizing enterocolitis (NEC). METHODS AND RESULTS The expression of MIF mRNA and protein in NEC guts was assayed by in situ hybridization and immunohistochemistry, respectively. Concentrations of MIF, interleukin (IL)-6 and IL-8 in the serum and in the supernatant of macrophage cultures were examined by ELISA. Increased expression of MIF mRNA and protein was observed in the NEC guts, mainly in the infiltrating macrophages in the mucosa and submucosal layers. Up-regulation of MIF was associated with the accumulation of macrophages and T cells. In addition, serum levels of MIF, IL-6 and IL-8 in NEC patients during the acute stage of the disease were significantly increased. The expression of MIF decreased both locally and systemically after the disease was resolved. MIF was also found to increase the secretion of IL-6 and IL-8 by macrophages isolated from healthy individuals in vitro in NEC. CONCLUSIONS MIF acts by stimulating macrophage production of IL-6 and IL-8. This further aggravates the inflammatory process by increasing the infiltration of neutrophils and activating inflammatory cells. The results of this study suggest that MIF plays an important role in the pathogenesis of NEC and may serve as a target for therapeutic intervention in NEC.
Collapse
|
97
|
Chan KL, Hui WC, Tam PKH. Prospective randomized single-center, single-blind Comparison of laparoscopic vs open repair of pediatric inguinal hernia. Surg Endosc 2005; 19:927-32. [PMID: 15920685 DOI: 10.1007/s00464-004-8224-3] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Accepted: 02/01/2005] [Indexed: 10/25/2022]
Abstract
BACKGROUND The repair of indirect inguinal hernia (IH) is one of the most common pediatric surgical procedures, and open surgery (OS) is the standard treatment. The aim of this study was to determine whether the recently developed laparoscopic repair (LR) of IH is superior to OS. METHODS Between February 2003 and February 2004, we randomly assigned 97 consecutive IH patients at our institution into OS and LR groups. Fourteen patients were excluded from the study for various reasons, leaving study population of 83 patients. After operation, multiple dressings were placed to blind observers to the operation type. Two pain scales, the children and Infants Postoperative Pain were used to assess postoperative pain. Acetaminophen (15 mg/kg/dose every 6 h) was given at a fixed pain score. Analgesic doses were compared. Parents also provided assessments of their children's recovery and wound appearance. RESULTS The amount of acetaminophen taken by the OS group (n = 42) was 1.05 +/- 1.248 doses per patient, whereas the amount taken by the LR group (n = 41) was 0.54 +/- 0.84 dose per patient (p = 0.032; 95% confidence interval 0.45-0.976). Laparoscopy detected 11 more bilateral hernias (p = 0.006). Although the operative times did not differ significantly for bilateral hernias (39.08 +/- 13.37 min vs 34.0 +/- 11.31 min, p = 0.623), it did differ for unilateral hernias (18.38 +/- 5.71 vs 23.25 +/- 6.26 min, p = 0.001). Five contralateral hernias were detected in the OS group on follow-up, but none were found in the LR group (p = 0.026). The scores given by parents for recovery and wound appearance were higher in the LR group (p = 0.05). CONCLUSIONS As compared with IH patients who undergo open surgery, those who have a laparoscopic repair suffer less pain, and their recovery and wound cosmesis are more satisfactory. With LR, contralateral hernias can be detected and repaired in a single operative procedure. This procedure takes slightly longer for unilateral than for bilateral hernias.
Collapse
|
98
|
Ho KMT, Li AZL, Yiu MK, Lee KC, Lui VCH, Fung PCW, Yiu TF, Tam PKH. Altered expression of aquaporin-2 in human explants with chronic renal allograft dysfunction. BJU Int 2005; 95:1104-8. [PMID: 15839941 DOI: 10.1111/j.1464-410x.2005.005475.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To investigate the distribution of aquaporins, a recently discovered family of transmembrane water channels, in human renal explants, with specific reference to chronic renal allograft dysfunction (CRAD). MATERIALS AND METHODS Immunohistochemistry for aquaporin-1 and -2 was used in 11 explants, of which five had clinically and histologically confirmed CRAD. Controls were taken from the six explants unaffected by CRAD and from histologically normal areas of six kidneys excised for renal tumours. RESULTS In the renal tumour control group, aquaporin-1 immunoreactivity was detected in the glomerular endothelium, Bowman's capsule, the proximal convoluted tubules and the thin limb of the loop of Henle, whereas immunoreactivity for aquaporin-2 was detected in the collecting ducts only. Of the explants without CRAD, where architecture was preserved, immunoreactivity for aquaporin-1 and -2 was the same as in the renal tumour controls. In the two explants with no CRAD and loss of collecting ducts, there was no aquaporin-2 immunoreactivity. In five explants with CRAD, immunoreactivity for aquaporin-2 was decreased or absent from the medulla to the cortex. The apparent decreased immunoreactivity of aquaporin-1 in this group was secondary to a decrease in the number of viable proximal tubules. CONCLUSION There was less aquaporin-2 immunoreactivity in human renal explants diagnosed with CRAD, starting from the medullary region. In explants with no CRAD and viable collecting ducts, or in normal controls, aquaporin-2 immunoreactivity remained unchanged. Aquaporins might be useful as markers for CRAD.
Collapse
|
99
|
Wong KKY, Khong PL, Lin SCL, Lam WWM, Lan LCL, Tam PKH. Post-operative magnetic resonance evaluation of children after laparoscopic anorectoplasty for imperforate anus. Int J Colorectal Dis 2005; 20:33-7. [PMID: 15322835 DOI: 10.1007/s00384-004-0620-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/25/2004] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND AIMS Laparoscopic anorectoplasty (LAR) is a relatively new procedure in the treatment of imperforate anus. Using magnetic resonance imaging (MRI), we evaluated the anatomical features of the anorectal region of children treated with LAR and compared this with conventional posterior sagittal anorectoplasty (PSARP). The findings were correlated with functional outcome. PATIENT/METHODS A retrospective review of ten children with the high/intermediate types of imperforate anus underwent LAR between May 2000 and December 2002. MRI of the pelvis was performed post-operatively and a semi-quantitative score was used to assess the degree of sphincter symmetry, peri-rectal fibrosis, and the position of the pull-through rectum. The defecation status of these patients was also recorded. Eight historical patients who had undergone PSARP served as a control group. RESULTS/FINDINGS When compared with PSARP patients, a significantly lower proportion of LAR patients had sphincter asymmetry (40 vs. 100%, p < 0.05) and peri-rectal fibrosis (40 vs. 87.5%, p < 0.05). The positioning of the rectum was, however, central for both groups (90 vs. 87.5%). No statistical correlation was found between defecation status and the degree of sphincter asymmetry or peri-rectal fibrosis. INTERPRETATION/CONCLUSION LAR allows more optimal anatomical reconstruction for patients with the high/intermediate types of imperforate anus. However, additional factors that are not correctable by surgery, such as intrinsic innervation deficiency, also influence the clinical outcome.
Collapse
|
100
|
Wong KKY, Fan AH, Lan LCL, Lin SCL, Tam PKH. Effective antibiotic regime for postoperative acute cholangitis in biliary atresia--an evolving scene. J Pediatr Surg 2004; 39:1800-2. [PMID: 15616934 DOI: 10.1016/j.jpedsurg.2004.08.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE The prompt use of empirical antibiotics is vital in managing post-Kasai cholangitis. The authors published findings of their clinical trial in 1991 and established the use of cefoperazone, with a response rate of 88.9%. Here its clinical use since its introduction is reviewed and the trend in its efficacy is assessed. METHODS A retrospective review was carried out between 1997 and 2003. All episodes of acute cholangitis in patients who underwent Kasai procedure were recorded. Cholangitis was defined as unexplained fever with derangement of liver enzymes. Cefoperazone was started empirically according to the established protocol, and the response to treatment was analyzed. RESULTS There were 19 patients with a total of 49 episodes of cholangitis. Cefoperazone was used as the first-line empirical antibiotic in 40 of these episodes. Only 30 showed successful response (75%). For the 10 unresponsive episodes, meropenem was used as second-line antibiotic with complete response in all. CONCLUSIONS The efficacy of cefoperazone in the treatment of post-Kasai cholangitis has decreased over the last years. This suggests a need for a more effective first-line empirical antibiotic. From this review, meropenem seems to be a suitable candidate, and a future prospective clinical trial is warranted.
Collapse
|