Biomedical subjects

E Shi

Publications and source records attributed to E Shi.

At least 19 recordsLinked to original sources

PubMed2002

Isolated and multisystem hepatic trauma in children: the true role of non-operative management.

We retrospectively reviewed children with hepatic injuries (HI) admitted to our institutions from January 1982 to December 1999. Specific comparison was made of isolated (IHT) and multisystem hepatic trauma (MHT). Over the 18-year period 127 patients were identified with HI, 91 (71%) with MHT and 36 with IHT. The median age was 8 years (range 13 months to 14 years). Motor vehicle injury was the most common mechanism in both groups, but bicycle injuries were more common in IHT ( P<0.001). Shock ( P=0.02), the requirement for blood transfusion ( P<0.001), and operative intervention for the HI ( P=0.001) were all significantly more common in MHT. The distribution of liver injury grades was similar between the two groups. Twenty-two (17.3%) children died and in 18 the HI was the main cause or contributed significantly. There were 19 and 3 deaths in the MHT and IHT groups, respectively, a difference that was not significant. After excluding children with minor HI, 27 (39%) required operative intervention within 24 h of their injury. This suggests that the high success rate for non-operative management of HIs in the literature may have been biased by the inclusion of a significant proportion of subclinical injuries.

Accidents, Traffic↗

PubMed2001

Design and synthesis of a series of (2R)-N(4)-hydroxy-2-(3-hydroxybenzyl)-N(1)- [(1S,2R)-2-hydroxy-2,3-dihydro-1H-inden-1-yl]butanediamide derivatives as potent, selective, and orally bioavailable aggrecanase inhibitors.

A pharmacophore model of the P1' site, specific for aggrecanase, was defined using the specificity studies of the matrix metalloproteinases and the similar biological activity of aggrecanase and MMP-8. Incorporation of the side chain of a tyrosine residue into compound 1 as the P1' group provided modest selectivity for aggrecanase over MMP-1, -2, and -9. A cis-(1S)(2R)-amino-2-indanol scaffold was incorporated as a tyrosine mimic (P2') to conformationally constrain 2. Further optimization resulted in compound 11, a potent, selective, and orally bioavailable inhibitor of aggrecanase.

Administration, Oral↗

PubMed2001

Identification of a novel membrane protein, HP59, with therapeutic potential as a target of tumor angiogenesis.

CM101, a polysaccharide isolated from the culture medium of Group B streptococcus, a neonatal pathogen, targets pathological angiogenesis and inhibits tumor growth in mice and humans. CM101 also targets neonatal lung and adult sheep lung endothelial cells. A gene encoding a transmembrane protein that interacts with CM101 was isolated from a sheep lung endothelial cell cDNA library. The gene, termed sp55, encodes a 495-amino acid polypeptide. COS-7 cells transfected with a vector containing sp55 express the SP55 protein-bound CM101 in a concentration-dependent manner. Stably transfected CHO cells also bound CM101. The corresponding human gene, hp59, was isolated from a human fetal lung cDNA library and had a predicted identity to SP55 of 86% over 495 amino acids. HP59 protein was shown by immunohistochemistry to be present in the pathological tumor vasculature of the lung, breast, colon, and ovary, but not in the normal vasculature, suggesting that the protein may be critical to pathological angiogenesis. The hp59 gene and/or the HP59 protein was not expressed in a variety of normal tissues, but was significantly expressed in human fetal lung, consistent with the pathophysiology of Group B streptococcus infections in neonates. Mice immunized with HP59 and SP55 peptides showed significant attenuation of tumor growth. Immunization effectively inhibited both the tumor angiogenesis and vasculogenesis processes, as evidenced by lack of both HP59- and CD34-positive vessels. These results and the immunohistochemistry data suggest a therapeutic potential for the CM101 target protein HP59 both as a drug target and as a vaccine against pathoangiogenesis.

Amino Acid Sequence↗

PubMed2000

Targeting and therapy of carcinoembryonic antigen-expressing tumors in transgenic mice with an antibody-interleukin 2 fusion protein.

The purpose of this study was to engineer a bivalent single-chain anticarcinoembryonic antigen (CEA) antibody and an interleukin 2 (IL-2) fusion protein derivative for selective tumor targeting of cytokines. The variable domains of a high affinity anti-CEA antibody, T84.66, were used to form a single-gene-encoded antibody [single-chain variable fragment joined to the crystallizable fragment, Fc (scFvFc)]. The fusion protein (scFvFc.IL-2) consisted of mouse IL-2-fused to the COOH-terminal end of the scFvFc. The engineered proteins were assembled as complete molecules and were similar to the intact anti-CEA monoclonal antibody (Mab) in antigen-binding properties. Based on IL-2 content of the fusion protein, its ability to support proliferation of CTLL-2 cells was identical with that of IL-2. Despite a molecular size similar to that of the intact Mab, the blood clearance of the fusion protein was markedly faster than that of the intact Mab or scFvFc. Incubation of radiolabeled scFvFc.IL-2 but not the intact or scFvFc antibodies in mouse serum was accompanied by the appearance of complexes, suggesting that the latter may contribute to the accelerated clearance of the fusion protein. Biodistribution and tumor targeting studies were carried out in CEA-transgenic mice bearing CEA-positive murine tumors as well as the antigen-negative parental tumor. The bivalent anti-CEA scFvFc had tumor localization properties similar to those of the intact Mab. Although fusion of IL-2 to the COOH-terminal end of the bivalent scFvFc altered its pharmacokinetic properties, the fusion antibody was able to target tumors specifically. Maximum uptake of the intact Mab, scFvFc, and scFvFc.IL-2 in CEA-positive tumors was 29.3 +/- 5.0, 19.5 +/- 2.1, and 6.6 +/- 0.9% injected dose/g, respectively. Maximum tumor localization ratios (CEA-positive/CEA-negative tumor) were similar for all three antibody types (4.6-6.0), demonstrating the antigen specificity of the tumor targeting. Significant antigen-specific targeting to CEA-positive normal tissues of transgenic mice was not observed. Although the tumor-targeting properties of the fusion protein were low, the growth of CEA-expressing (P = 0.01) but not antigen-irrelevant (P = 0.22) syngeneic tumor cells was inhibited after treatment of transgenic mice with the anti-CEA-IL-2 antibody. Therapy of CEA-expressing tumors was improved after i.v. administration of the fusion protein (P = 0.0001). These studies indicate that anti-CEA antibody-directed cytokine targeting may offer an effective treatment for CEA-expressing carcinomas. The availability of an immunocompetent CEA transgenic mouse model will also help to determine the immunotherapeutic properties of these fusion proteins.

Animals↗

PubMed2000

Oesophageal atresia in twins.

The twin incidence is higher in infants with oesophageal atresia (OA) than in the general population. The purpose of this study was to review the twin OA information from five institutions and evaluate possible links between the development of OA and the twinning process. Data were compared, combined, and analysed. There was a total of 1,215 infants with OA, of whom 50 were from a twin pregnancy and 1 from a triplet pregnancy. Two sets of twins were concordant for OA. Mean birth weights and gestational ages were lower in the twin infants (P < 0.0005) and survival was lower in twins (65%, P < 0.005) than singletons. The anatomical variant of pure OA without fistula was seen in proportionally fewer twins (4%) than in singletons (7%). Multiple anomalies were present in 40% of twins compared with 33% of singletons, although this did not reach statistical significance. OA in our multicentre population was more common in twins. Several possible mechanisms are put forward to explain the apparent link between twinning and OA. Further analysis of this aspect of OA may aid in understanding the aetiology of this congenital anomaly.

Esophageal Atresia↗

PubMed2000

True hermaphroditism.

OBJECTIVE: True hermaphroditism is a rare cause of atypical genitalia which presents significant diagnostic and management challenges. We present the clinical and laboratory findings and management of four patients with true hermaphroditism. METHODOLOGY: Case studies from a teaching hospital and literature review. RESULTS: All four patients had atypical genitalia identified at birth. All had a palpable gonad, only one of which was palpable at birth. Three patients were 46XX (SRY -ve) and one 46XY (SRY +ve). Three patients were raised as females (two 46XX and one 46XY) and one as a male. All four patients were found to have an ovotestis present. CONCLUSIONS: The management of true hermaphroditism is controversial and requires a multidisciplinary approach. It has many implications for both the parent and child. We discuss the issues involved for the patients and their parents.

Disorders of Sex Development↗

PubMed2000

Early primary repair of long gap esophageal atresia: the VATER operation.

Despite the numerous approaches described for the management of neonates with "long gap" esophageal atresia, controversy still exists as to the preferred method. Delayed primary anastomosis is probably the most frequently adopted practice, but often the native esophagus is abandoned, and the long gap is bridged by some form of esophageal replacement. A case is reported of a 1.38-kg newborn with pure esophageal atresia and a long gap undergoing early primary repair. The technique used in this patient and the various options available for management of long-gap esophageal atresia are discussed.

Anastomosis, Surgical↗

PubMed2000

Phosphospecific antibodies reveal focal adhesion kinase activation loop phosphorylation in nascent and mature focal adhesions and requirement for the autophosphorylation site.

Focal adhesion kinase (FAK) is a key signaling molecule regulating cellular responses to integrin-mediated adhesion. Integrin engagement promotes FAK phosphorylation at multiple sites to achieve full FAK activation. Phosphorylation of FAK Tyr-397 creates a binding site for Src-family kinases, and phosphorylation of FAK Tyr-576/Tyr-577 in the kinase domain activation loop enhances catalytic activity. Using novel phosphospecific antibody reagents, we show that FAK activation loop phosphorylation is significantly elevated in cells expressing activated Src and is an early event following cell adhesion to fibronectin. In both cases, this regulation is largely dependent on Tyr-397. We also show that the FAK activation loop tyrosines are required for maximal Tyr-397 phosphorylation. Finally, immunostaining analyses revealed that tyrosine-phosphorylated forms of FAK are present in both newly forming and mature focal adhesions. Our findings support a model for reciprocal activation of FAK and Src-family kinases and suggest that FAK/Src signaling may occur during both focal adhesion assembly and turnover.

3T3 Cells↗

PubMed2000

[Measurement of tumor angiogenesis in primary lung cancer].

OBJECTIVE: To study tumor angiogenesis in primary lung cancer and its relation with lymph node metastasis, tumor cell apoptosis, and cell proliferation. METHODS: Intratumor microvessel was detected by factor VIII polyclonal antibody using immunohistochemistry. Tumor cell apoptosis was detected by TUNEL method. Cell proliferation was analyzed by flow cytometry. RESULTS: Intratumor microvessel density (MD) was significantly lower in stage I lung cancer than in stage II and stage III (P < 0.01). MD was significantly higher in the tumors with lymph node metastasis (P < 0.01). With the increase in MD, there would be a 1.2-fold increase in the risk of lymph node metastasis (P < 0.01). With the increase of MD, apoptosis index (AI) of the tumor significantly decreased, but no relationship between MD and cell proliferation index (PI) was observed. CONCLUSION: Tumor angiogenesis promotes growth and metastasis of lung cancer. Tumor angiogenesis also can inhibit the apoptosis of lung cancer.

Adult↗

PubMed1999

[Quantitative study of vascular endothelial growth factor expression in primary lung cancer].

OBJECTIVE: To study the expression levels of vascular endothelial growth factor (VEGF) and its relation with intratumoral microvessel density (MD), cellular proliferation activity (PI), and lymph node metastasis of primary lung cancer. METHODS: Surgical samples of 53 patients with primary lung cancer were measured. The VEGF was immunofluorescence stained with VEGF polyclonal antibody. The propidium iodide was used to stain cellular DNA. VEGF expression levels and DNA content were analyzed quantitatively using flow cytometry. Intratumoral microvessel density was detected by factor VIII polyclonal antibody using immunohistochemistry. RESULTS: VEGF expression levels (FI) were high in lung cancer (1.3 +/- 0.6, positive ratio 73.58%). The cellular proliferation activity (PI) in VEGF-positive tumors was significantly higher than that in VEGF-negative tumors (29.8% +/- 9.2% vs 18.7% +/- 6.5%, P < 0.01). The intratumoral microvessel density (MD) in VEGF-positive tumors was higher than that in VEGF-negative tumors (19.4 +/- 11.3 vs 12.3 +/- 8.0, P < 0.05). No association was found between the MD and PI (r = 0.169, P > 0.05). The VEGF expression levels in lung cancer tissues with lymph node metastasis (n = 33) were significantly higher than that in those without lymph node metastasis (n = 20) (1.5 +/- 0.6 vs 1.0 +/- 0.5, P < 0.01). CONCLUSION: VEGF plays an important role in the growth and metastasis of lung cancer.

Adenocarcinoma↗

PubMed1998

Congenital central hypoventilation syndrome and Hirschsprung's disease.

Five cases of the Hirschsprung's disease-congenital central hypoventilation syndrome (CCHS) association are presented and 41 other published cases reviewed. These children have a distinct pattern of associated features, an equal sex incidence, and a characteristic spectrum of disease severity which suggests that the condition is genetically distinct from other cases of Hirschsprung's disease. While approximately 1.5% of Hirschsprung's disease patients, and 10% of those with total colonic aganglionosis, will have CCHS, up to 50% of CCHS patients will have Hirschsprung's disease. Approximately 20% of CCHS/Hirschsprung patients will also have neuroblastoma or ganglioneuroma, usually multiple. Abnormalities of the eye and autonomic nervous system are also common. The ventilatory abnormality is usually evident on the first day of life. The aganglionosis is also severe, with more than half (59%) of the patients having aganglionosis extending into the small bowel.

Deglutition Disorders↗

PubMed1997

Scatter factor stimulates tumor growth and tumor angiogenesis in human breast cancers in the mammary fat pads of nude mice.

Scatter factor (SF) (also known as hepatocyte growth factor) is a plasminogen-related growth factor that induces tumor cell motility, invasion, and angiogenesis. Its receptor is a tyrosine kinase encoded by c-met, a protooncogene. Human breast cancer cells express SF and c-met in vivo; but human breast cancer cell lines do not produce SF in vitro. To determine whether SF can modulate the in vivo growth of human breast cancers within a natural mammary environment, we studied the orthotopic growth of SF-transfected (SF+) versus control (SF-) clones of MDAMB231 human mammary carcinoma cells in the mammary fat pads of athymic nude mice. SF+ clones expressed SF mRNA and produced very high titers of SF protein, whereas SF- clones did not express SF mRNA or produce detectable SF protein. Two SF+ clones (21 and 29) showed significantly increased tumor growth rates, reaching 3- to 4-fold larger primary tumor volumes and weights by time of killing (p < 0.001), as well as higher rates of axillary lymph node metastasis (p < 0.02), as compared with two SF- clones (32 and 34). In contrast, in vitro proliferation rates, two-dimensional colony formation, and soft agar colony formation were no greater in SF+ than in SF- clones. We performed further studies to investigate the discrepancy between the in vivo and in vitro growth results. Tumor extracts from SF+ clone (21 + 29) tumors had 50-fold higher SF content than did SF- clone (32 + 34) tumors, confirming high-level SF expression in vivo in SF+ tumors. Immunostaining of tumor sections for proliferating cell nuclear antigen revealed only a modest increase in the proportion of cycling cells in SF+ versus SF- tumors (70% versus 60%, respectively). The terminal deoxytransferase-labeling index was equally low (approximately 1%) in SF+ and SF- tumors, suggesting that apoptosis was not responsible for the slower growth of SF- tumors. However, SF+ tumors had significantly higher tumor microvessel densities than SF- tumors (p < 0.001). Moreover, there were much higher titers of chemotactic activity for microvascular endothelial cells in cell-conditioned media and primary tumor extracts from SF+ clones as compared with SF- clones. As demonstrated using the rat cornea assay, there was more angiogenic activity in SF+ tumor extracts than in SF- extracts. The increased chemotactic and angiogenic activities in SF+ tumor extracts were not explained by secondary alterations in the content of the angiogenic mediator, vascular endothelial growth factor, or the antiangiogenic glycoprotein, thrombospondin-1; and those activities were neutralized using an anti-SF monoclonal antibody. These findings suggest that SF promotes the orthotopic growth of human breast cancers, at least in part, by stimulating tumor angiogenesis.

Adipose Tissue↗

PubMed1996

Fundoplication in children: experience with 106 cases.

BACKGROUND: Gastro-oesophageal reflux (GOR) is a physiological problem in infancy that can become pathological and life-threatening in certain cases. Fundoplication has been shown previously to be effective in the control of this problem when medical therapy fails. METHODS: A retrospective review of the hospital records and the Department of Paediatric Surgery database was carried out, in order to demonstrate the Prince of Wales Children Hospital's (POWCH) experience with 106 fundoplications between February 1989 and March 1993. RESULTS: There was a failure rate of 7.5% and a long-term mortality rate of 7.8%. The children most at risk of mortality and morbidity are shown to be the neurologically impaired. The special problems associated with these children as compared with neurologically normal children with pathological GOR are discussed and the literature reviewed. CONCLUSION: Fundoplication is shown to be a safe operation that can be life-saving in certain circumstances.

Cerebral Palsy↗

PubMed1994

Inositolhexakisphosphate (InsP6): an antagonist of fibroblast growth factor receptor binding and activity.

Fibroblast growth factors (FGF), which have been implicated in tumor cell growth and angiogenesis, have biological activities that appear to be mediated by both heparinlike extracellular matrix sites and transmembrane tyrosine kinase receptor sites. In the present study, we demonstrated that inositolhexakisphosphate (InsP6) inhibits basic FGF (bFGF) binding to heparin. Our spectrofluorometric analyses demonstrated that InsP6 not only bound to bFGF, presumably within the bFGF heparin-binding domain, but also protected bFGF from degradation by trypsin. Also, InsP6 inhibited the cellular binding of bFGF and other fibroblast growth factor family members such as acidic FGF (aFGF) and K-FGF in a saturable and dose-dependent manner. Furthermore, concentrations as low as 100 microM InsP6 inhibited bFGF-induced DNA synthesis in AKR-2B fibroblasts, as well as the growth of bFGF- and K-FGF-transfected NIH/3T3 cells. Together, these results indicate that InsP6 may serve as a useful antagonist of FGF activity.

Animals↗

PubMed1993

Control of fibroblast growth factor receptor kinase signal transduction by heterodimerization of combinatorial splice variants.

A differentiated liver cell (HepG2), which exhibits a dose-dependent growth-stimulatory and growth-inhibitory response to heparin-binding fibroblast growth factor type 1 (FGF-1), displays high- and low-affinity receptor phenotypes and expresses specific combinatorial splice variants alpha 1, beta 1, and alpha 2 of the FGF receptor (FGF-R) gene (flg). The extracellular domains of the alpha and beta variants consist of three and two immunoglobulin loops, respectively, while the intracellular variants consist of a tyrosine kinase (type 1) isoform and a kinase-defective (type 2) isoform. The type 2 isoform is also devoid of the two major intracellular tyrosine autophosphorylation sites (Tyr-653 and Tyr-766) in the type 1 kinase. An analysis of ligand affinity, dimerization, autophosphorylation, and interaction with src homology region 2 (SH2) substrates of the recombinant alpha 1, beta 1, and alpha 2 isoforms was carried out to determine whether dimerization of the combinatorial splice variants might explain the dose-dependent opposite mitogenic effects of FGF. Scatchard analysis indicated that the alpha and beta isoforms exhibit low and high affinity for ligand, respectively. The three combinatorial splice variants dimerized in all combinations. FGF enhanced dimerization and kinase activity, as assessed by receptor autophosphorylation. Phosphopeptide analysis revealed that phosphorylation of Tyr-653 was reduced relative to phosphorylation of Tyr-766 in the type 1 kinase component of heterodimers of the type 1 and type 2 isoforms. The SH2 domain substrate, phospholipase C gamma 1 (PLC gamma 1), associated with the phosphorylated type 1-type 2 heterodimers but was phosphorylated only in preparations containing the type 1 kinase homodimer. The results suggest that phosphorylation of Tyr-653 within the kinase catalytic domain, but not Tyr-766 in the COOH-terminal domain, may be stringently dependent on a trans intermolecular mechanism within FGF-R kinase homodimers. Although phosphotyrosine 766 is sufficient for interaction of PLC gamma 1 and other SH2 substrates with the FGF-R kinase, phosphorylation and presumably activation of substrates require the kinase homodimer and phosphorylation of Tyr-653. We propose that complexes of phosphotyrosine 766 kinase monomers and SH2 domain signal transducers may constitute unactivated presignal complexes whose active or inactive fate depends on homodimerization with a kinase or heterodimerization with a kinase-defective monomer, respectively. The results suggest a mechanism for control of signal transduction by different concentrations of ligand through heterodimerization of combinatorial splice variants from the same receptor gene.

Amino Acid Sequence↗

PubMed1992

Expression and immunochemical analysis of rat and human fibroblast growth factor receptor (flg) isoforms.

Potentially 96 splice variants among four genes that code for the human heparin-binding fibroblast growth factor receptor family complicate study of structure, metabolism, and function of single isoforms in mammalian cells. As an alternative, we expressed structural subdomains and isoforms of the flg receptor gene in bacteria and baculoviral-infected insect cells. We developed and characterized a panel of 16 isoform and domain-specific polyclonal and monoclonal antibodies. The panel of antibodies was used to distinguish mature glycosylated ligand-binding and kinase-active and -inactive recombinant isoforms in baculoviral insect cells and transfected mammalian cells and natural isoforms in rat prostate and human liver cells. The results revealed a cell type-specific expression of the flg gene and isoforms that result from combinations of splice variations. Reactive epitopes of monoclonal antibodies against both the three (alpha) and two (beta) immunoglobulin-like disulfide loop extracellular domain isoforms were mapped by cross-reactivity with synthetic polypeptide sequences and deletion mutants expressed in bacteria. The native alpha and beta receptor isoforms differed in display of shared epitopes and suggested that the NH2-terminal Loop I and COOH-terminal Loops II and III of the alpha isoform are interactive. Although the common Loops II and III appear qualitatively sufficient for ligand binding, the results suggest that tertiary relationships among loops in the three and two loop isoforms are distinct and, therefore, the two isoforms may have distinct activities. Spatial models for arrangement of immunoglobulin-like loops in the extracellular domain of the two isoforms are presented.

Amino Acid Sequence↗

PubMed1992

Growth factors in breast cancer: mitogenesis to transformation.

While endocrine steroid hormones have been known for many years to regulate normal and malignant mammary epithelium, recent studies have led to an appreciation of polypeptide growth factors as locally-acting autocrine and paracrine effectors. In the current article we summarize what is known about growth factor regulation and action in the normal mammary gland and about perturbations of the steroid-growth factor interplay as cancer progresses. A major theme is that oncogenic activation modulates both regulation of production and function of growth factors in the mammary gland.

Animals↗

PubMed1991

16-kilodalton heparin binding (fibroblast) growth factor type one appears in a stable 40-kilodalton complex after receptor-dependent internalization.

Incubation of 16-kDa 125I-labeled heparin binding (acidic fibroblast) growth factor type one (HBGF-1) with human hepatoma cells and normal rat hepatocytes resulted in the appearance of a stable 125I-labeled complex with an apparent molecular mass of 40 kDa. The complex could be isolated with specific antibodies against HBGF-1. In contrast to membrane receptor-bound 125I-HBGF-1, the complex was resistant to dissociation by detergents, acid, heat, and reducing or denaturing agents. Formation of a stable complex did not require treatment with cross-linking agents. Appearance of the 40-kDa complex was dependent on time, temperature, and enriched culture medium. Conditions that enhanced or reduced display of specific HBGF-1 membrane receptor sites enhanced or reduced the appearance of the 40-kDa complex. Dansylcadaverine, chloroquine, and staurosporine blocked the appearance of the 40-kDa complex concurrent with the blockage of internalization of the receptor-bound HBGF-1. Two-dimensional gel electrophoretic analysis, metabolic labeling with L-[35S]cysteine, and recovery of 16-kDa HBGF-1 from the 40-kDa complex after base treatment suggest involvement of a 24-kDa cellular protein in the complex formation. These results suggest a potentially novel receptor-dependent pathway for metabolism of HBGF-1.

Alkaloids↗