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Biomedical subjects

K Y Kwong

Publications and source records attributed to K Y Kwong.

16 recordsLinked to original sources
PubMed2006

Expression of transforming growth factor beta (TGF-b1) by human preterm lung inflammatory cells.

Using a previously published model of human BPD this study examines whether preterm lung inflammatory cells produce transforming growth factor beta 1 (TGF-beta1), a cytokine pivotal in pathogenesis of bronchopulmonary dysplasia (BPD), and whether TGF-beta1 expression is regulated by inflammation. Lung inflammatory cells (neutrophils and macrophages) recovered in the broncho-alveolar (BAL) fluid of premature infants intubated for respiratory distress after birth expressed TGF-b1 mRNA and protein. Total and bioactive TGF-beta1 were abundantly found in the BAL fluid of the same infants. In cell culture stimulation by lipopolysaccharide (LPS) did not result in any further expression of total or bioactive TGF-beta1 by neonatal lung inflammatory cells over constitutive concentrations. In conclusion, lung inflammatory cells from premature infants are a source of TGF-beta1 but LPS does not regulate TGF-b1 production in these cells.

Bronchoalveolar Lavage Fluid↗
PubMed2006

Ability to control persistent asthma in obese versus non-obese children enrolled in an asthma-specific disease management program (breathmobile).

To determine if asthma control was more difficult to achieve in obese versus non-obese asthmatic children, retrospective analysis was performed on obese and non-obese Los Angeles inner-city children (2 to 18 years of age) with persistent asthma. No difference in time required to achieve control of asthma, ability to maintain control of asthma, baseline pulmonary functions, and number of controllers prescribed was found between the two groups. We conclude that in a Los Angeles inner-city pediatric population, obesity is not a factor in the ability to control asthma.

Adolescent↗
PubMed2001

Regulation of pro-inflammatory cytokine expression by curcumin in hyaline membrane disease (HMD).

Persistent expression of pro-inflammatory cytokines is believed to play a major role in the pathogenesis of chronic lung disease (CLD) in premature infants. Inhibition of pro-inflammatory cytokine production in the lungs of preterm newborns may result in the attenuation of CLD. Curcumin is a naturally occurring phenolic compound derived from the food spice tumeric with broad based in vitro anti-inflammatory properties. In this study lung inflammatory cells from preterm newborns at risk for the development of CLD were derived via modified broncho-alveolar lavage and stimulated ex vivo with lipopolysaccharide (LPS) (10 ng/ml). Curcumin was added to these cultures at 0, 0.5 and 20 uM concentrations. Pro-inflammatory cytokine, TNFalpha, IL-1beta and IL-8 protein was measured from the culture supernatants 12 hours post culture. For control, adult peripheral blood mononuclear cells (PBMC) were cultured under the same conditions. Both neonatal lung inflammatory cells and adult PBMC produced high levels of pro-inflammatory cytokines in response to LPS. Curcumin produced significant inhibition of IL-1beta and IL-8 but minimal inhibition of TNFalpha expression by preterm lung inflammatory cells at 20 uM concentrations. Adult PBMC expression of IL-8 was significantly inhibited by curcumin at 20 uM concentrations. Therefore, curcumin inhibits pro-inflammatory cytokine production (TNFalpha, IL-1beta and IL-8) by lung inflammatory cells ex vivo. Pathways involved with curcumin regulation of these cytokines are developmentally intact and functional in premature infants. Curcumin may be effective as a therapeutic agent in the attenuation of CLD.

Adult↗
PubMed2001

Nuclear localization of EGF receptor and its potential new role as a transcription factor.

Epidermal growth factor receptor (EGFR) has been detected in the nucleus in many tissues and cell lines. However, the potential functions of nuclear EGFR have largely been overlooked. Here we demonstrate that nuclear EGFR is strongly correlated with highly proliferating activities of tissues. When EGFR was fused to the GAL4 DNA-binding domain, we found that the carboxy terminus of EGFR contained a strong transactivation domain. Moreover, the receptor complex bound and activated AT-rich consensus-sequence-dependent transcription, including the consensus site in cyclin D1 promoter. By using chromatin immunoprecipitation assays, we further demonstrated that nuclear EGFR associated with promoter region of cyclin D1 in vivo. EGFR might therefore function as a transcription factor to activate genes required for highly proliferating activities.

Animals↗
PubMed2000

Beta-catenin, a novel prognostic marker for breast cancer: its roles in cyclin D1 expression and cancer progression.

Beta-catenin can function as an oncogene when it is translocated to the nucleus, binds to T cell factor or lymphoid enhancer factor family members, and transactivates its target genes. In this study, we demonstrate that cyclin D1 is one of the targets of beta-catenin in breast cancer cells. Transactivation of beta-catenin correlated significantly with cyclin D1 expression both in eight breast cell lines in vitro and in 123 patient samples. More importantly, we found that high beta-catenin activity significantly correlated with poor prognosis of the patients and was a strong and independent prognostic factor in breast cancer. Our studies, therefore, indicated that beta-catenin can be involved in breast cancer formation and/or progression and may serve as a target for breast cancer therapy.

Adult↗
PubMed2000

The ets protein PEA3 suppresses HER-2/neu overexpression and inhibits tumorigenesis.

Because HER-2/neu overexpression is important in cancer development, we looked for a method of suppressing the cell transformation mediated by HER-2/neu overexpression. We have identified that the DNA-binding protein PEA3, which is encoded by a previously isolated gene of the ets family, specifically targeted a DNA sequence on the HER-2/neu promoter and downregulated the promoter activity. Expression of PEA3 resulted in preferential inhibition of cell growth and tumor development of HER-2/neu-overexpressing cancer cells. This is a new approach to targeting HER-2/neu overexpression and also provides a rationale to the design for repressors of diseases caused by overexpression of pathogenic genes.

3T3 Cells↗
PubMed2000

Bioactive transforming growth factor-beta in the lungs of extremely low birthweight neonates predicts the need for home oxygen supplementation.

Transforming growth factor-beta (TGF-beta) is a peptide implicated in tissue injury and repair but its role in the premature human lung remains unclear. In the present study, we used a TGF-beta responsive-promoter-luciferase construct in mink lung epithelial cells to quantify levels of biologically active TGF-beta (BA-TGF-beta) in the endotracheal aspirate (ETA) fluid from 16 extremely low birthweight neonates [6 M/10 F, mean GA 26 weeks (range 23-30), mean BW 774 g (range 555-1,075)]. ETA fluid was obtained on day 1 and then every 4 days up to 32 days. BA-TGF-beta levels were low (92 +/- 19 pg/ml) in the first 24 h of life and then increased 5- to 10-fold with peak BA-TGF-beta levels (400 +/- 50 pg/ml) on day 20-25. BA-TGF-beta levels were higher in male than female infants (p = 0.0056). Prenatal steroids decreased significantly the amount of BA-TGF-beta recovered. High initial levels of BA-TGF-beta persisted over time and were predictive of the need for oxygen therapy at home. We conclude that abundant BA- TGF-beta is present in the lungs of preterm infants and speculate that it may be involved in inflammatory and repair processes encountered in acute and chronic lung disease.

Bronchoalveolar Lavage Fluid↗
PubMed1998

A novel splice variant of HER2 with increased transformation activity.

The HER2 proto-oncogene (also known as neu or c-erbB-2) belongs to the epidermal growth factor receptor family. HER2 is frequently amplified in human carcinomas. Gene amplification or overexpression of HER2 has been correlated with poor prognosis in several human cancers. Point mutation in the rat HER2 homolog, neu, is involved in the formation of rat neuroblastomas. However, no similar mutation in HER2 has been found in human cancers. Here we report the identification of a novel alternative splicing form of HER2 (deltaHER2) in human cell lines. An exon 16 amino acids long in the extracellular domain was deleted in deltaHER2. Deletion mutations in the corresponding region were shown previously to be involved in the formation of mammary carcinomas in transgenic mice. In the focus-formation assay, deltaHER2 showed much stronger transformation activity than did wild-type HER2. This result suggests that the deleted 16-amino acid exon may play a regulatory role in HER2 transformation activity.

3T3 Cells↗
PubMed1998

The effects of IL-10 on proinflammatory cytokine expression (IL-1beta and IL-8) in hyaline membrane disease (HMD).

Deficient expression of the counterregulatory cytokine IL-10 by lung inflammatory cells may facilitate chronic inflammation and the pathogenesis of hyaline membrane disease (HMD), in premature infants. To determine if pathways which regulate proinflammatory cytokines in response to human recombinant IL-10 (rIL-10) were functional in the lungs of these neonates, bronchoalveolar lavage (BAL)-derived lung inflammatory cells (predominantly macrophages and neutrophils) from infants with HMD were cultured in the presence of lipopolysaccharide (LPS) and increasing concentrations of (rIL-10). The expression of IL-1beta and IL-8 protein was assessed 24 h later. IL-10 protein was also measured from the BAL aspirates of these newborns at 4-day intervals over the first month of life. In cell culture IL-1beta expression was inhibited by rIL-10 in a dose-dependent fashion while IL-8 expression was inhibited by higher concentrations of rIL-10. IL-10 protein was undetectable from BAL fluid of the premature infants sampled over 28 days. The results demonstrate that lung inflammatory cells, which do not express IL-10 in vivo, are capable of responding to rIL-10 in cell culture with reduction of IL-1beta and IL-8 expression. These data support the rationale for the development of rIL-10 as a potential anti-inflammatory agent in the treatment of HMD.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

Differential regulation of IL-8 by IL-1beta and TNFalpha in hyaline membrane disease.

Mechanisms that regulate cytokine-mediated inflammation in the lungs of preterm infants, including factors which regulate production of the chemokine IL-8, remain poorly defined. Sequential bronchoalveolar lavage samples were obtained from preterm newborns with hyaline membrane disease over a 28-day period. Bronchoalveolar lavage cell cytokine relationships were evaluated and the differential regulation of IL-8 by IL-1beta and TNFalpha was studied in a short-term culture system. In vivo, IL-8 and IL-1beta protein levels correlated closely with each other and with macrophage counts. In cell culture, exogenous anti-IL-1beta antibody led to a 40% maximum inhibition (approximately) of IL-8 production by lipopolysaccharide stimulated lung inflammatory cells. Comparable amounts of exogenous anti-TNFalpha antibodies achieved a 15% maximum inhibition (approximately) of IL-8 production. Anti-IL-1beta and anti-TNFalpha antibodies in combination did not inhibit IL-8 production beyond that achieved by anti-IL-1beta antibody alone. These results, in preterm newborns, support the concept of lung inflammation mediated in part by a macrophage, IL-1beta, and IL-8 cell cytokine pathway. The results also suggest that factors other than IL-1beta and TNFalpha regulate IL-8 expression in the lungs of preterm infants.

Antibodies, Blocking↗
PubMed1996

Undetectable interleukin (IL)-10 and persistent IL-8 expression early in hyaline membrane disease: a possible developmental basis for the predisposition to chronic lung inflammation in preterm newborns.

We are interested in determining whether premature birth alters expression of counterregulatory cytokines which modulate lung inflammation. Production of proinflammatory cytokines tumor necrosis factor alpha. IL-1 beta, and IL-8 is regulated in part by the antiinflammatory cytokine IL-10. For preterm newborns with hyaline membrane disease, deficiencies in the ability of lung macrophages to express antiinflammatory cytokines may predispose to chronic lung inflammation. We compared the expression of pro- and antiinflammatory cytokines at the mRNA and protein level in the lungs of preterm and term newborns with acute respiratory failure from hyaline membrane disease or meconium aspiration syndrome. Four sequential bronchoalveolar lavage (BAL) samples were obtained during the first 96 h of life from all patients. All patients rapidly developed an influx of neutrophils and macrophages. Over time, cell populations in both groups became relatively enriched with macrophages. The expression of proinflammatory cytokine mRNA and/or protein was present in all samples from both patient groups. In contrast, IL-10 mRNA was undetectable in most of the cell samples from preterm infants and present in the majority of cell samples from term infants. IL-10 concentrations were undetectable in lavage fluid from preterm infants with higher levels in a few of the BAL samples from term infants. These studies demonstrate that 1) IL-10 mRNA and protein expression by lung inflammatory cells is related to gestational age and 2) during the first 96 h of life neutrophil cell counts and IL-8 expression decrease in BAL from term infants, but remain unchanged in BAL samples from preterm infants.

Bronchoalveolar Lavage↗
PubMed1994

Epstein-Barr virus associated aplastic anaemia and hepatitis.

We report a Chinese girl with Epstein-Barr virus (EBV) associated aplastic anaemia and hepatitis. Epstein-Barr virus genome was demonstrated in her bone marrow cells and EBV-specific serology suggested reactivation of EBV infection. She was initially treated with anti-thymocyte globulin (ATG) and methylprednisolone but with no haematologic response, and liver function continued to deteriorate. She was then treated with acyclovir. Her aplastic anaemia improved and hepatitis resolved, and there was eradication of EBV genome from her bone marrow cells.

Acyclovir↗
PubMed1993

Epstein-Barr virus in carcinoma of the vulva.

AIMS: To detect the presence of Epstein-Barr virus (EBV) in cases of vulval carcinoma in Chinese patients living in Hong Kong. METHODS: Formalin fixed, paraffin wax embedded blocks from eight cases of vulval carcinoma and six age matched controls of non-neoplastic vulval tissue were analysed for the presence of EBV DNA using the polymerase chain reaction (PCR). RESULTS: EBV DNA was detected in only one of the eight cases of vulval carcinoma cases while it was detected in four out of the six control cases. CONCLUSIONS: There is no demonstrable association between EBV and vulval carcinoma. Detection of EBV in non-neoplastic vulval epithelium highlights its ubiquitous presence in the lower female genital tract.

Aged↗