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Tso WWY, Chan KL, Lee TMC, Rao N, Lee SL, Jiang F, Chan SHS, Wong WHS, Wong RS, Tung KTS, Yam JC, Liu APY, Chua GT, Rosa Duque JS, Lam ALN, Yip KM, Leung LK, Wang Y, Sun J, Wang G, Chan GCF, Wong ICK, Ip P. Mental health & maltreatment risk of children with special educational needs during COVID-19. Child Abuse Negl 2022; 130:105457. [PMID: 35033372 PMCID: PMC8743505 DOI: 10.1016/j.chiabu.2021.105457] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 12/15/2021] [Accepted: 12/20/2021] [Indexed: 05/16/2023]
Abstract
BACKGROUND Children with special educational needs (SEN) are more vulnerable during the COVID-19 pandemic with risk of poor mental wellbeing and child maltreatment. OBJECTIVE To examine the impact of COVID-19 on the mental health of children with SEN and their maltreatment risk. PARTICIPANTS AND SETTING 417 children with SEN studying at special schools and 25,427 children with typical development (TD) studying at mainstream schools completed an online survey in April 2020 in Hong Kong during school closures due to COVID-19. METHOD Emotional/behavioural difficulties, quality of life and parental stress of children with SEN were compared with typically developed children using mixed effect model. Linear regression analyses were performed to explore factors associated with child emotional/behavioural difficulties and parental stress during the pandemic. Chi-square test was performed to detect the differences in maltreatment risk before and during COVID-19. RESULTS Children with SEN had significantly poorer overall quality of life (68.05 vs 80.65, p < 0.01). 23.5% of children had at least one episode of severe physical assault and 1.9% experienced very severe physical assault during COVID-19. Rates of physical assault increased significantly (59.8% vs. 71.2% p < 0.001) while children with mental disorders had increased risk of severe physical assault comparing to those without mental disorders (RR = 1.58, ꭓ2 = 5.19 p = 0.023). CONCLUSION Children with SEN had poorer mental health than typically developed children during the COVID-19 pandemic. Maltreatment risk for children with SEN is higher in comparison to pre-COVID-19 era. Surveillance of child maltreatment, continuity of medical and rehabilitation care to support children with SEN are essential during a disease pandemic.
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Affiliation(s)
- Winnie W Y Tso
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong; State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong
| | - Ko Ling Chan
- Department of Applied Social Sciences, The Hong Kong Polytechnic University, Hong Kong.
| | - Tatia M C Lee
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong; Laboratory of Neuropsychology, The University of Hong Kong, Pokfulam, Hong Kong
| | - Nirmala Rao
- Faculty of Education, The University of Hong Kong, Pokfulam, Hong Kong
| | - S L Lee
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Fan Jiang
- Department of Developmental and Behavioral Pediatrics, Pediatric Translational Medicine Institute, National Children's Medical Center-Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Sophelia H S Chan
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Wilfred H S Wong
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Rosa S Wong
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Keith T S Tung
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Jason C Yam
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Anthony P Y Liu
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Gilbert T Chua
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Jaime S Rosa Duque
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Almen L N Lam
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - K M Yip
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - L K Leung
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Yuliang Wang
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Jin Sun
- Department of Early Childhood Education, The Education University of Hong Kong, Hong Kong
| | - Guanghai Wang
- Department of Developmental and Behavioral Pediatrics, Pediatric Translational Medicine Institute, National Children's Medical Center-Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Godfrey C F Chan
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Ian C K Wong
- Centre for Safe Medication Practice and Research, Department of Pharmacology and Pharmacy, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong; Research Department of Practice and Policy, University College London School of Pharmacy, London, United Kingdom
| | - Patrick Ip
- Department of Paediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong.
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Tso WYW, Hui SK, Lee TMC, Liu APY, Ip P, Cheng K, Fong D, Chang D, Ho FKW, Yip KM, Ku D, Cheuk DKL, Luk CW, Shing MK, Leung LK, Khong PL, Chan GCF. QOL-25. MICROSTRUCTURAL BRAIN CHANGES ASSOCIATED WITH NEUROCOGNITIVE AND FUNCTIONAL OUTCOMES OF INTRACRANIAL GERM CELL TUMUOR SURVIVORS – A DIFFUSIONAL KURTOSIS IMAGING STUDY. Neuro Oncol 2020. [PMCID: PMC7715703 DOI: 10.1093/neuonc/noaa222.687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
BACKGROUND
Childhood intracranial germ cell tumour (iGCT) survivors are prone to radiotherapy-related neurotoxicity which can lead to neurocognitive dysfunction. Diffusion kurtosis imaging (DKI) is a MRI technique that quantifies microstructural changes in the grey and white matter of the brain. This study aims to investigate the associations between MR-DKI metrics, the cognitive and functional outcomes of childhood iGCT survivors.
METHOD
20 childhood iGCT survivors who had received cranial radiotherapy were recruited. DKI parameters were determined for iGCT survivors and 18 control subjects. Neurocognitive assessment using the Hong Kong Wechsler Intelligence Scales for Children (HKWISC)/ Wechsler Adult Intelligence Scale – Revised (WAIS-R) and functional assessment using the Lansky/ Karnofsky performance scales were performed for GCT survivors.
RESULTS
There were significant negative correlation between the IQ scores and the mean diffusivity (MD) in multiple white matter regions of iGCT survivors including: anterior limb of internal capsule, superior fronto-occipital fasciculus, anterior corona radiata, uncinate fasciculus, cingulum and hippocampus. Mean kurtosis (MK) values of the superior fronto-occipital fasciculus were positively correlated with IQ scores. For grey matter, the MD of the olfactory, insula, caudate, heschl gyrus, parahippocampal gyrus, hippocampus, anterior cingulum, frontal inferior operculum, middle and superior temporal gyrus, middle and superior frontal orbital gyri, cuneus and precentral gyrus were negatively correlated with IQ scores. Most of the microstructural changes with associated functional impairment were white matter regions.
CONCLUSION
Our study identified vulnerable brain regions with significant white and grey matter microstructural changes that were associated with impaired cognitive function or deficits in physical functioning.
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Affiliation(s)
- Wan-Yee Winnie Tso
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, Hong Kong
| | - Sai Kam Hui
- Department of Diagnostic Radiology, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, Hong Kong
| | - Tatia Mei Chun Lee
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, Hong Kong
| | - Anthony Pak Yin Liu
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, Hong Kong
| | - Patrick Ip
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, Hong Kong
| | - Kevin Cheng
- Department of Neurosurgery, Queen Mary Hospital, Hong Kong, Hong Kong
| | - Daniel Fong
- Department of Nursing, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, Hong Kong
| | - Dorita Chang
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, Hong Kong
| | - Frederick K W Ho
- Institute of Health and Wellbeing, University of Glasgow, Glasgow, United Kingdom
| | - Ka Man Yip
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, Hong Kong
| | - Dennis Ku
- Hong Kong Children’s Hospital, Hong Kong, Hong Kong
| | | | | | | | - L K Leung
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, Hong Kong
| | - Pek Lan Khong
- Department of Diagnostic Radiology, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, Hong Kong
| | - Godfrey Chi Fung Chan
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, Hong Kong
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3
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Chen ZY, Leung LK, Huang Y. Reply to K.W. Lee, H.J. Lee and C.Y. Lee. J Nutr 2002. [DOI: 10.1093/jn/132.4.786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Z. Y. Chen
- Department of Biochemistry, The Chinese University of Hong Kong Shatin, NT, Hong Kong
| | - L. K. Leung
- Department of Biochemistry, The Chinese University of Hong Kong Shatin, NT, Hong Kong
| | - Y. Huang
- Department of Physiology The Chinese University of Hong Kong Shatin, NT, Hong Kong
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4
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Abstract
Green tea catechins, including (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG), are oxidized and dimerized during the manufacture of black tea and oolong tea to form orange-red pigments, theaflavins (TF), a mixture of theaflavin (TF1), theaflavin-3-gallate (TF2A), theaflavin-3'-gallate (TF2B) and theaflavin-3,3'-digallate (TF3). The present study was designed to compare the antioxidant activities of individual TF with that of each catechin using human LDL oxidation as a model. All catechins and TF tested inhibited Cu(+2)-mediated LDL oxidation. Analysis of the thiobarbituric acid-reactive substances (TBARS) and conjugated dienes produced during LDL oxidation revealed that the antioxidant activity was in the order: TF3 > ECG > EGCG > or = TF2B > or = TF2A > TF1 > or = EC > EGC. Four TF derivatives also demonstrated a dose-dependent antioxidant activity in Cu(+2)-mediated LDL oxidation at concentrations of 5-40 micromol/L. These results demonstrate that the TF present in black tea possess at least the same antioxidant potency as catechins present in green tea, and that the conversion of catechins to TF during fermentation in making black tea does not alter significantly their free radical-scavenging activity.
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Affiliation(s)
- L K Leung
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, The People's Republic of China
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5
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Abstract
Soy consumption has been associated with a lower incidence of breast cancer in Southeast Asia. Among the phytochemicals in soy, genistein has been suggested to be chemopreventive. Because genistein is an estrogen-receptor (ER) agonist, the chemopreventive mechanism has been attributed to its ability to compete with estrogen for receptor binding. In this study, we used an ER-positive cell line to investigate the effects of different genistein concentrations on the apoptotic response. The threshold concentration at which a significant number of cells underwent apoptosis was titrated to be 25 micromol/L. At or above this concentration, c-jun N-terminus kinase was activated and Bax and Bcl-2 expression were both elevated. The elevated Bcl-2 protein might neutralize the proapoptotic effect of Bax. Therefore, the mechanism of genistein-induced apoptosis at this concentration might rely largely on the stress pathway rather than the pathway mediated by the Bcl-2 family of proteins.
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MESH Headings
- Antineoplastic Agents/pharmacology
- Apoptosis/drug effects
- Breast Neoplasms/genetics
- Breast Neoplasms/metabolism
- Breast Neoplasms/prevention & control
- Dose-Response Relationship, Drug
- Female
- Gene Expression Regulation, Neoplastic/drug effects
- Genes, bcl-2/drug effects
- Genes, jun
- Genes, p53/drug effects
- Genistein/metabolism
- Genistein/pharmacology
- Humans
- In Vitro Techniques
- JNK Mitogen-Activated Protein Kinases
- Luciferases/genetics
- Luciferases/metabolism
- Mitogen-Activated Protein Kinases/genetics
- Mitogen-Activated Protein Kinases/metabolism
- Proto-Oncogene Proteins/drug effects
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-bcl-2/drug effects
- Proto-Oncogene Proteins c-bcl-2/genetics
- Proto-Oncogene Proteins c-bcl-2/metabolism
- RNA, Messenger/biosynthesis
- Receptors, Estrogen/antagonists & inhibitors
- Receptors, Estrogen/metabolism
- Glycine max
- Stress, Physiological/complications
- Stress, Physiological/metabolism
- Tumor Cells, Cultured
- bcl-2-Associated X Protein
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Affiliation(s)
- L K Leung
- Food and Nutritional Sciences Programme, Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong
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6
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Abstract
Conjugated linoleic acids (CLAs) have been shown to be a strong anticarcinogen in a number of animal models. Our previous study demonstrated that CLA as a whole was extremely unstable in air. The present study was undertaken further to examine the oxidative stability of individual CLA isomers using the combination of gas-liquid chromatography (GLC) and silver ion high-performance liquid chromatography (Ag-HPLC). It was found that CLA as a whole oxidized rapidly and more than 80% was degraded within 110 h in air at 50 degrees C. Four c,c-CLA isomers were most unstable followed by four c,t-CLA isomers. In contrast, four t,t-CLA isomers were relatively stable under the same experimental conditions. Both the oxygen consumption and the GLC analysis revealed that 200 ppm jasmine green tea catechins (GTCs) exhibited protection to CLA and were even stronger than 200 ppm butylated hydroxytoluene (BHT) when added to either CLA or canola oil containing 10% CLA. The present study emphasized that oxidative unstability of CLA should not be overlooked although CLA has many biological effects.
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Affiliation(s)
- L Yang
- Department of Chemistry, Henan Normal University, Xinxiang, Henan, The Chinese University of Hong Kong, Shatin, New Territories
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7
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Abstract
Tumorigenesis is related to the dysregulation of cell growth or cell death pathways. Hence, elucidation of the mechanisms involved in the modulation of pro- or anti-apoptotic proteins is important in furthering understanding of breast cancer aetiology and may aid in designing prevention and treatment strategies. In the present study, we examined the role of 17beta-oestradiol on the regulation of apoptosis in the breast cancer cell line MCF-7. Using multi-probe RNAase protection assays, we found changes in the mRNA levels of several Bcl-2 family proteins upon treatment of MCF-7 cells with 17beta-oestradiol. Unexpectedly, we found a paradoxical effects of 17beta-oestradiol on two anti-apoptotic proteins Bcl-2 and Bcl-x. Treatment with 17beta-oestradiol resulted in up-regulation of Bcl-2 mRNA and protein, but down-regulated Bcl-x(L) mRNA and protein. The effect of 17beta-oestradiol on Bcl-x(L) occurred at concentration-dependent fashion. The effect was specific to 17beta-oestradiol since other steroid hormones exert no effect on Bcl-x(L). Tamoxifen, an anti-oestrogen, blocked the down-regulation of Bcl-x(L) by 17beta-oestradiol demonstrating this effect is oestrogen receptor-dependent. We speculate that different members of the Bcl-2 family proteins may be regulated through different pathway and these pathways may be modulated by 17beta-oestradiol.
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Affiliation(s)
- L K Leung
- Basic Research Laboratory, Division of Basic Sciences, National Cancer Institute, Frederick, MD 21702-1201, USA
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8
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Leung LK, Wang TT. Differential effects of chemotherapeutic agents on the Bcl-2/Bax apoptosis pathway in human breast cancer cell line MCF-7. Breast Cancer Res Treat 1999; 55:73-83. [PMID: 10472781 DOI: 10.1023/a:1006190802590] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The present study explored the effects of three commonly used chemotherapeutic agents on the Bcl-2/Bax apoptosis pathway and the interaction of these chemotherapeutic drugs with the estradiol-mediated regulation of this pathway. Our results showed that: (1) Treatment of MCF-7 cells with Adriamycin resulted in time- and concentration-dependent decreases in Bcl-2 and increases in Bax mRNA and protein levels. (2) Camptothecin elicited similar trends on Bcl-2 and Bax as Adriamycin, while etoposide, at 50-100 fold (1-5 microM) the effective concentration of Adriamycin and camptothecin, only resulted in an increase in Bax mRNA levels. (3) Adriamycin and camptothecin, but not etoposide, were effective in suppressing estradiol-stimulated increases in Bcl-2 mRNA levels. Our study provides evidence that the Bcl-2/Bax apoptosis pathway may be differentially regulated by chemotherapeutic agents. In addition, interaction between these agents and estradiol on the Bcl-2/Bax apoptosis pathway may also exist.
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Affiliation(s)
- L K Leung
- Basic Research Laboratory, NCI-Frederick Cancer Research and Development Center, NIH, MD 21702-1201, USA
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9
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Cohen H, Howland MA, Luciano DJ, Rubin RN, Kutt H, Hoffman RS, Leung LK, Devinsky O, Goldfrank LR. Feasibility and pharmacokinetics of carbamazepine oral loading doses. Am J Health Syst Pharm 1998; 55:1134-40. [PMID: 9626375 DOI: 10.1093/ajhp/55.11.1134] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The pharmacokinetics and adverse effects of an oral loading dose of carbamazepine administered in tablet or suspension form were studied. Patients on a hospital epilepsy unit who were to receive carbamazepine as a discharge medication were randomly assigned to receive either an oral 8-mg/kg loading dose of the tablet formulation or the same dose of the suspension on an empty stomach. Blood samples were drawn before and at intervals up to 12 hours after the loading dose. Adverse effects were evaluated subjectively and objectively. Total and free serum carbamazepine and carbamazepine-10, 11-epoxide (CBZE) concentrations were determined by high-performance liquid chromatography. Six adult patients were enrolled in and completed the study. All the patients achieved therapeutic total carbamazepine levels; the suspension group did so within two hours and the tablet group within five hours. Maximum serum carbamazepine concentrations ranged from 7.10 to 9.92 mg/L, area under the concentration-versus-time curve from 54.85 to 82.23 micrograms.hr/L, and terminal elimination half-life from 14.05 to 15.71 hours. Adverse effects were mild, few, and short-lived; none of the patients developed gastrointestinal toxicity. Adverse effects were not associated with total or free carbamazepine and CBZE concentrations or with total or free CBZE:carbamazepine ratios. An oral loading dose of carbamazepine 8 mg/kg achieved therapeutic levels within two hours when given as a suspension and within five hours when given as tablets and was well tolerated in all patients.
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Affiliation(s)
- H Cohen
- Arnold & Marie Schwartz College of Pharmacy and Health Sciences, Long Island University, Brooklyn, NY, USA
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10
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Wilson MW, Leung LK, Hong JT, Glauert HP. Effect of the peroxisome proliferators ciprofibrate and perfluorodecanoic acid on eicosanoid concentrations in rat liver. Adv Exp Med Biol 1998; 400A:439-45. [PMID: 9547588 DOI: 10.1007/978-1-4615-5325-0_59] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- M W Wilson
- Department of Nutrition and Food Science, University of Kentucky, Lexington 40506, USA
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11
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Abstract
Peroxisome proliferators, which include several hypolipidemic drugs, plasticizers and other chemicals, induce hepatic tumors in rodents. These chemicals alter the expression of enzymes involved in lipid metabolism, such as the cytochrome P450 4A family and peroxisomal beta-oxidation enzymes. Previous studies have shown that the peroxisome proliferator ciprofibrate reduces eicosanoid concentrations in rat livers and primary hepatocyte cultures, yet the mechanism is still unclear. In this study we examined cyclooxygenases 1 and 2 (COX-1 and COX-2) and cytosolic phospholipase A2 (cPLA2) to determine whether the rate-limiting enzymes in the eicosanoid synthetic pathway are altered by ciprofibrate. Rats were fed 0.01% ciprofibrate for 3, 6, or 10 days. Western analysis revealed that COX-2 protein was induced by ciprofibrate (up to 13-fold at day 10), but that calcium-dependent (Ca-D) cPLA2 protein was not different from controls. The enzyme activity of calcium-independent (Ca-I) cPLA2 in ciprofibrate-treated rats was increased 2-fold, whereas Ca-D cPLA2 and total COX activities were not affected. Using enzyme kinetics, we found that COX-1 (Ki = 143 microM) and Ca-I cPLA2 (Ki = 121 microM) were competitively inhibited by ciprofibrate, but the inhibition was not physiologically significant. COX-2 and Ca-D cPLA2 were not inhibited by ciprofibrate. These results show that ciprofibrate increases Ca-I cPLA2 enzyme activity and COX-2 protein expression.
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Affiliation(s)
- L K Leung
- Nutritional Sciences Program, University of Kentucky, Lexington 40506, USA
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12
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Abstract
In the current study we examined the regulation of Bak, a death promoter of an apoptotic pathway, in the human breast cancer cell line MCF-7. We observed a time-dependent increase in both Bak mRNA and protein levels which appeared to correlate well with the increase in cell density. We also found that treatment of cells with 17beta-estradiol resulted in inhibition of the time-dependent increases in Bak mRNA and protein. The effects of estradiol appeared to be via estrogen receptor as treatment of cells with progesterone did not effect Bak expression. Our study provides additional molecular evidence for (1) a link between apoptosis pathways and cell-cell and/or cell-cell matrix interactions and (2) a role for estradiol in the modulation of signals between apoptosis pathways and cell-cell and/or cell-cell matrix interactions.
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Affiliation(s)
- L K Leung
- Division of Basic Sciences, National Cancer Institute, NCI-Frederick Cancer Research and Development Center, NIH, MD 21702-1201, USA
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13
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Leung LK, Glauert HP. Lack of correlation between hepatic prostaglandin concentrations and DNA synthesis after the administration of phenobarbital and the peroxisome proliferator ciprofibrate in rats. Toxicology 1997; 123:101-9. [PMID: 9347925 DOI: 10.1016/s0300-483x(97)00110-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Peroxisome proliferators are a class of chemicals that induce and promote hepatic tumors in rodents. These compounds are not genotoxic, and the mechanism by which they induce and promote tumors is poorly understood. Phenobarbital (PB) also is a hepatic tumor promoter that produces a different natural history than peroxisome proliferators during the promotion of hepatocarcinogenesis. In addition, opposite effects on hepatic eicosanoid concentrations have been demonstrated previously. In this experiment, we examined whether higher hepatic eicosanoid concentrations correlated with the induction of DNA synthesis after the administration of PB or the peroxisome proliferator ciprofibrate (CIP). PB (0.05% in diet) or CIP (0.01% in diet) was fed to rats from 1-10 days. For the rats treated with CIP, the peroxisomal enzyme fatty acyl-CoA oxidase increased gradually from day 1 to day 10. PB treated rats had a higher cytochrome P450 2B1/2 activity over the entire course of feeding. Hepatic prostaglandins E2 and F2alpha concentrations were significantly reduced in the rats treated with CIP, while no significant differences were seen between the control and PB-treated rats. DNA synthesis was increased in both PB-treated and CIP-treated rats. These results show that higher eicosanoid concentrations do not correlate with the induction of hepatic DNA synthesis by CIP or PB.
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Affiliation(s)
- L K Leung
- Department of Nutrition and Food Science, University of Kentucky, Lexington 40506-0054, USA
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14
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Glauert HP, Hong JT, Leung LK, Wilson MW. Role of eicosanoid metabolism in carcinogenesis by peroxisome proliferators. Ann N Y Acad Sci 1996; 804:719-21. [PMID: 8993604 DOI: 10.1111/j.1749-6632.1996.tb18679.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- H P Glauert
- Department of Nutrition and Food Science, University of Kentucky, Lexington 40506, USA
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15
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Abstract
Nuclear factor kappaB (NF-kappaB) is an important stress-induced transcription factor in many cell types. In this study we examined if the hepatic tumor promoting agent phenobarbital could activate NF-kappaB in the liver. Rats were fed 0.05% phenobarbital in the diet for 3, 6, or 10 days. Benzyloxyresorufin dealkylase activity was greatly increased in rats receiving phenobarbital. The DNA binding activity of NF-kappaB was determined using electrophoretic mobility shift assays. After 3 days, NF-kappaB activity was increased two-fold in rats receiving phenobarbital. NF-kappaB activity continued to increase at 6 and 10 days in rats fed phenobarbital, with a four-fold increase seen at day 10. Cold competition and antibody supershift experiments showed the DNA binding activity to be specific for NF-kappaB. These data show that phenobarbital activates hepatic NF-kappaB in rats.
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Affiliation(s)
- Y Li
- Graduate Center for Toxicology, University of Kentucky, Lexington, Kentucky, 40506, USA.
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16
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Li Y, Leung LK, Glauert HP, Spear BT. Treatment of rats with the peroxisome proliferator ciprofibrate results in increased liver NF-kappaB activity. Carcinogenesis 1996; 17:2305-9. [PMID: 8968042 DOI: 10.1093/carcin/17.11.2305] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Nuclear factor kappaB (NF-kappaB) is an important stress-induced transcription factor in many cell types, including hepatocytes. Previous studies have shown that reactive oxygen species, including hydrogen peroxide, are potent activators of NF-kappaB. Peroxisome proliferators are a group of rodent chemical carcinogens that have been proposed to act by increasing reactive oxygen in the liver. These results led us to consider whether peroxisome proliferators would increase NF-kappaB activity in the liver. Here we demonstrate that rats fed diets containing the peroxisome proliferator ciprofibrate exhibit increased hepatic NF-kappaB DNA-binding activity. This observation suggests that NF-kappaB may contribute, in part, to peroxisome proliferator-mediated changes in the liver.
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Affiliation(s)
- Y Li
- Graduate Center for Toxicology, University of Kentucky, College of Medicine, Lexington 40536-0084, USA
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Leung LK, Glauert HP. Reduction of the concentrations of prostaglandins E2 and F2alpha, and thromboxane B2 in cultured rat hepatocytes treated with the peroxisome proliferator ciprofibrate. Toxicol Lett 1996; 85:143-9. [PMID: 8644126 DOI: 10.1016/0378-4274(96)03639-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Several hypolipidemic drugs, plasticizers and other chemicals induce peroxisome proliferation and hepatic tumors in rodents, but the mechanism by which they induce tumors is not fully understood. Their carcinogenic activity may be related to alterations in gene expression, such as induction of peroxisomal beta-oxidation enzymes or of the cytochrome P450 4A family. These enzymes metabolize lipids, including eicosanoids and their precursor fatty acids. Because eicosanoids likely play a role in the carcinogenic process, alterations in their concentration by xenobiotics may be important in their carcinogenic or promoting activities. In this study we used isolated hepatocytes to study if peroxisome proliferators alter the metabolism of prostaglandins (PG) and thromboxanes (Tx). Isolated rate hepatocytes were cultured for 4 days with 2 concentrations of ciprofibrate (CIP): 100 and 400 microM. Fatty acyl CoA oxidase activities of the 100 and 400 microM CIP treatment groups at the end of the experiment were increased 5.3 and 9.6 times, respectively. TxB2 and PGF2alpha concentrations in cultures treated with CIP were significantly lower than the control at days 3 and 4, whereas a lower concentration of PGE2 was seen at day 4 only. These studies show that PG and Tx concentrations in cultured hepatocytes are lowered by the peroxisome proliferator CIP.
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Affiliation(s)
- L K Leung
- Department of Nutrition and Food Science, University of Kentucky, Lexington 40506-0054, USA
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18
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Leung LK, Davis R. Life-threatening hemolysis following a brown recluse spider bite. J Tenn Med Assoc 1995; 88:396-7. [PMID: 7475015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- L K Leung
- Vanderbilt University Medical Center, Nashville, USA
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19
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Lee YS, Collie MJ, Leung LK, Seidlin M, Beatrice ST. Comparison of Immobilon-N membrane and other membranes for the detection of HIV-1 genome in high risk patients using PCR. J Virol Methods 1991; 33:217-22. [PMID: 1939509 DOI: 10.1016/0166-0934(91)90021-q] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The polymerase chain reaction (PCR) was used for detection of the HIV-1 genome from the peripheral blood lymphocytes of high risk patients. The gag regions of HIV-1 (SK38-SK39) were chosen to amplify viral DNA and the amplified products were spotted onto membrane filters and hybridized with a 32P-labeled SK19 probe. Nitrocellulose, nylon and polyvinylidene difluoride (PVDF) membrane filters were used and compared in dot-blot hybridization. PVDF (Immobilon-N, trade name) filter membranes were demonstrated to be the best membranes on the basis of hybridization data and showed a stronger signal on autoradiograms than the other two types (nitrocellulose and nylon).
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Affiliation(s)
- Y S Lee
- Division of Retrovirology and Immunobiology, New York City Dept. of Health, New York 10016
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20
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Wong KH, Hau SK, Chan PW, Leung LK, Choy CL, Wong HK. XeCl excimer laser interaction with partially stabilized zirconia target. ACTA ACUST UNITED AC 1991. [DOI: 10.1007/bf00724742] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Abstract
Enzymatic cycling assays for the determination of L-phenylalanine and phenylpyruvate in deproteinized tissue extracts are described. Assay 1 couples glutamine transaminase K with L-phenylalanine dehydrogenase. Assay 2 combines phenylalanine dehydrogenase, L-amino acid oxidase, and catalase. In both assays, tyrosine and some other amino acids (or their alpha-keto acid analogs) can replace phenylalanine (or phenylpyruvate) to a small extent. Thus, if phenylalanine is to be measured a correction must be made for the nonspecificity of the reaction. By removing phenylalanine on a cation-exchange column it was possible to measure phenylpyruvate in tissue extracts. Concentrations of phenylpyruvate (mumol/kg) in normal rat liver, kidney, and brain were 2.1 +/- 1.1 (n = 8), 1.8 +/- 0.4 (n = 4), and 3.3 +/- 0.6 (n = 4), respectively.
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Affiliation(s)
- A J Cooper
- Department of Biochemistry, Cornell University, Medical College, New York, New York 10021
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22
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Saigo K, Shatsky M, Levitt LJ, Leung LK. Interaction of histidine-rich glycoprotein with human T lymphocytes. J Biol Chem 1989; 264:8249-53. [PMID: 2566603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Histidine-rich glycoprotein (HRGP), a human plasma and platelet protein, interacts with multiple ligands in vitro, including heparin, plasminogen, thrombospondin, and fibrinogen/fibrin. In this study, the binding of HRGP to human T lymphocytes was characterized. The binding was specific, concentration-dependent, saturable, and reversible. Scatchard plot analysis revealed two classes of binding sites: the high affinity class had an apparent dissociation constant (Kd) of 1.92 X 10(-8) M, with 0.92 X 10(4) sites/cell, and the low affinity class had a Kd of 4.97 X 10(-7) M, with 3.7 X 10(4) sites/cell. HRGP binding to T cells in the presence of HRGP-depleted serum was comparable to that observed in buffer. Dot-blot analysis showed that HRGP bound to specific T cell proteins. Using both HRGP affinity chromatography and immunoprecipitation with affinity-purified anti-HRGP IgG, a major 56-kDa HRGP-binding protein in surface labeled T cell lysates was demonstrated. The 56-kDa protein was shown not to be related to the CD2 molecule on T cells. The binding characteristics of HRGP to T lymphocytes indicate a specific ligand-receptor interaction. This is the first demonstration of HRGP binding to a cell surface, and its binding to human T cells may play an important role in T lymphocyte biology.
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Affiliation(s)
- K Saigo
- Department of Medicine, Stanford University Medical School, California 94305
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23
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Blandina P, Knott PJ, Leung LK, Green JP. Stimulation of histamine H2 receptor in rat hypothalamus releases endogenous norepinephrine. J Pharmacol Exp Ther 1989; 249:44-51. [PMID: 2709335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The effect of histamine (HA) on the release of endogenous norepinephrine (NE) from superfused rat hypothalamic and striatal slices was assessed. Measurements were made by high-performance liquid chromatography with electrochemical detection. Superfusion with HA (0.1-80 microM) resulted in a concentration-dependent increase (10-220%) of NE release from hypothalamus but was ineffective in the striatum. The process was Ca++-dependent and was unaffected by blockade of monoamine oxidase. The H2 agonists, dimaprit (50 microM) and impromidine (10 microM), increased NE release from hypothalamic slices 3-fold and 2-fold, respectively. Tiotidine (10 microM), an H2 antagonist, did not alter the spontaneous release of NE but completely abolished the effect of dimaprit. To increase the ability of the tissue to sustain NE release on repeated stimulation, tyrosine was added to the perfusion medium. Under these conditions 10 microM HA produced, in two consecutive stimuli, a 1.9-fold increase. Two consecutive stimuli by 80 microM HA elicited a 3.2- and a 2.9-fold increase. Under the same conditions, 50 microM ranitidine, another H2 antagonist, but not pyrilamine, an H1 antagonist, completely blocked the effect of 10 microM HA. Although NE release was increased in the presence of tyrosine, tyrosine did not increase the tissue levels of NE. These experiments imply that H2 receptor activation increases release of NE from the rat hypothalamus. Since in the hypothalamic slice, noradrenergic nerve endings are cut from their cell bodies, the modulatory event must have occurred at the nerve terminals.
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Affiliation(s)
- P Blandina
- Department of Pharmacology, Mount Sinai School of Medicine, City University of New York, New York
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Abstract
The spermatozoon of Lepidogalaxias salamandroides possesses an acrosome (putative), one or two perforatoria (putative) but no nine-triplet centrioles. Two elongated mitochondria (12 micron long) are situated in parallel between the nucleus (20 micron long) and the axoneme (53 micron long). The above features are unique among other teleosts with internal fertilization. The presence of an "acrosome" in this primitive teleost supports the hypothesis that this structure has been secondarily lost in teleosts during evolution. The uncertainty of phylogenetic placement of this fish is reflected by its unique sperm ultrastructure.
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Affiliation(s)
- L K Leung
- Zoology Department, University of Queensland, St. Lucia, Australia
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Jaffe EA, Ruggiero JT, Leung LK, Doyle MJ, McKeown-Longo PJ, Mosher DF. Cultured human fibroblasts synthesize and secrete thrombospondin and incorporate it into extracellular matrix. Proc Natl Acad Sci U S A 1983; 80:998-1002. [PMID: 6341993 PMCID: PMC393515 DOI: 10.1073/pnas.80.4.998] [Citation(s) in RCA: 195] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Thrombospondin, a major glycoprotein released from alpha granules of thrombin-stimulated platelets, is a disulfide-bonded trimer of 160-kilodalton subunits. Cultured human foreskin and fetal lung fibroblasts secreted thrombospondin (determined by enzyme-linked immunosorbent assay) into the culture medium in a time-dependent manner (15.7 and 5.8 micrograms per 10(6) cells per 24 hr, respectively); secretion was blocked by cycloheximide. [3H]Thrombospondin was isolated from [3H]leucine-labeled fibroblast postculture medium and from cell layers with rabbit polyclonal or mouse monoclonal anti-thrombospondin coupled to staphylococcal protein A-Sepharose. The immunologically isolated [3H]thrombospondin migrated in NaDodSO4/polyacrylamide gels with purified marker platelet thrombospondin both with and without reduction. Immunofluorescence microscopy using rabbit polyclonal and mouse monoclonal anti-thrombospondin antibodies localized thrombospondin to the fibrillar extracellular matrix surrounding the cells. Thus, cultured human fibroblasts secrete thrombospondin and incorporate it into the extracellular matrix.
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