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Guo SY, Wei LY, Song BB, Hu YT, Jiang Z, Zhao DD, Xu YH, Lin YW, Xu SM, Chen SB, Huang ZS. Design, synthesis and evaluation of 2-pyrimidinylindole derivatives as anti-obesity agents by regulating lipid metabolism. Eur J Med Chem 2023; 260:115729. [PMID: 37607439 DOI: 10.1016/j.ejmech.2023.115729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/08/2023] [Accepted: 08/13/2023] [Indexed: 08/24/2023]
Abstract
Obesity, a global pandemic posing a growing threat to human health, necessitates the development of effective and safe anti-obesity agents. Our previous studies highlighted the lipid-lowering effects of indolylquinazoline Bouchardatine and its derivatives. In this study, we employed scaffold hopping and simplification strategies to design and synthesize two new series derivatives by modifying the D ring. Extensive discussions have been conducted regarding the structure-activity relationship between lipid-lowering activity and the new compounds. These discussions have resulted in the discovery of 2-pyrimidinylindole derivatives as a promising scaffold for anti-obesity treatment. The new 2-pyrimidinylindole derivatives exhibited comparable lipid-lowering activity to the previously reported indolylquinazoline derivatives, including SYSU-3d and R17, with reduced toxicity. The most potent compound, 5a, demonstrated a larger therapeutic index, improved aqueous solubility and oral bioavailability compared to the previous lead compounds. In vivo evaluation indicated that 5a effectively reduced lipid accumulation in adipose tissue, improved glucose tolerance, and mitigated insulin resistance and liver function damage caused by a high-fat and high-cholesterol diet. Mechanism studies indicated that 5a may regulate lipid metabolism through the modulation of the PPARγ signaling pathway. Overall, our study has identified a highly active compound 5a, and provided the basis for further development of 2-pyrimidinylindole as a promising scaffold for obesity treatment.
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Affiliation(s)
- Shi-Yao Guo
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou, 510006, China
| | - Li-Yuan Wei
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou, 510006, China
| | - Bing-Bing Song
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou, 510006, China
| | - Yu-Tao Hu
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou, 510006, China
| | - Zhi Jiang
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou, 510006, China
| | - Dan-Dan Zhao
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou, 510006, China
| | - Yao-Hao Xu
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou, 510006, China
| | - Yu-Wei Lin
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou, 510006, China
| | - Shu-Min Xu
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou, 510006, China
| | - Shuo-Bin Chen
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou, 510006, China.
| | - Zhi-Shu Huang
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou, 510006, China.
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Xu YH, Hu YT, Xu SM, Song BB, Yuan H, Zhao DD, Guo SY, Jiang Z, Wei LY, Rao Y, Tan JH, Huang SL, Li QJ, Chen SB, Huang ZS. Design and Synthesis of Bouchardatine Derivatives as a Novel AMP-Activated Protein Kinase Activator for the Treatment of Colorectal Cancer. J Med Chem 2023. [PMID: 37253101 DOI: 10.1021/acs.jmedchem.3c00085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Metabolic reprogramming is a crucial hallmark of tumorigenesis. Modulating the reprogrammed energy metabolism is an attractive anticancer therapeutic strategy. We previously found a natural product, bouchardatine, modulated aerobic metabolism and inhibited proliferation in the colorectal cancer cell (CRC). Herein, we designed and synthesized a new series of bouchardatine derivatives to discover more potential modulators. We applied the dual-parametric high-content screening (HCS) to evaluate their AMP-activated protein kinase (AMPK) modulation and CRC proliferation inhibition effect simultaneously. And we found their antiproliferation activities were highly correlated to AMPK activation. Among them, 18a was identified with nanomole-level antiproliferation activities against several CRCs. Interestingly, the evaluation found that 18a selectively upregulated oxidative phosphorylation (OXPHOS) and inhibited proliferation by modulating energy metabolism. Additionally, this compound effectively inhibited the RKO xenograft growth along with AMPK activation. In conclusion, our study identified 18a as a promising candidate for CRC treatment and suggested a novel anti-CRC strategy by AMPK activating and OXPHOS upregulating.
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Affiliation(s)
- Yao-Hao Xu
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Yu-Tao Hu
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Shu-Min Xu
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Bing-Bing Song
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Hao Yuan
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Dan-Dan Zhao
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Shi-Yao Guo
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Zhi Jiang
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Li-Yuan Wei
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Yong Rao
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Jia-Heng Tan
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Shi-Liang Huang
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Qing-Jiang Li
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Shuo-Bin Chen
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Zhi-Shu Huang
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
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Jiang XC, Tu FH, Wei LY, Wang BZ, Yuan H, Yuan JM, Rao Y, Huang SL, Li QJ, Ou TM, Wang HG, Tan JH, Chen SB, Huang ZS. Discovery of a Novel G-Quadruplex and Histone Deacetylase (HDAC) Dual-Targeting Agent for the Treatment of Triple-Negative Breast Cancer. J Med Chem 2022; 65:12346-12366. [PMID: 36053318 DOI: 10.1021/acs.jmedchem.2c01058] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The development of triple-negative breast cancer (TNBC) is highly associated with G-quadruplex (G4); thus, targeting G4 is a potential strategy for TNBC therapy. Because concomitant histone deacetylases (HDAC) inhibition could amplify the impact of G4-targeting compounds, we designed and synthesized two novel series of G4/HDAC dual-targeting compounds by connecting the zinc-binding pharmacophore of HDAC inhibitors to the G4-targeting isaindigotone scaffold (1). Among the new compounds, a6 with the potent HDAC inhibitory and G4 stabilizing activity could induce more DNA G4 formation than SAHA and 1 in TNBC cells. Remarkably, a6 caused more G4-related DNA damage and G4-related differentially expressed genes, consistent with its effect on disrupting the cell cycle, invasion, and glycolysis. Furthermore, a6 significantly suppresses the proliferation of various TNBC cells and the MDA-MB-231 xenograft model without evident toxicity. Our study suggests a novel strategy for TNBC therapeutics through dual-targeting HDAC and G4.
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Affiliation(s)
- Xin-Chen Jiang
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Fang-Hai Tu
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Li-Yuan Wei
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Bo-Zheng Wang
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Hao Yuan
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Jing-Mei Yuan
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Yong Rao
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Shi-Liang Huang
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Qing-Jiang Li
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Tian-Miao Ou
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Hong-Gen Wang
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Jia-Heng Tan
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Shuo-Bin Chen
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
| | - Zhi-Shu Huang
- School of Pharmaceutical Sciences, Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Sun Yat-sen University, Guangzhou 510006, China
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Wei LY, Gong CX, Cao BY, Li XQ, Liang XJ, Li WJ, Wu D, Liu M, Su C, Chen JJ. [Genetic and clinical analysis of X-linked hypophosphatemic rickets]. Zhonghua Er Ke Za Zhi 2021; 59:678-683. [PMID: 34333921 DOI: 10.3760/cma.j.cn112140-20210311-00201] [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] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Objective: To investigate the clinical and genetic features, and treatment of X-linked hypophosphatemic rickets (XLH). Methods: In this retrospective study, we reviewed the medical records of 25 pediatric patients with XLH who were admitted to Department of Endocrinology Genetics and Metabolism,Beijing Children's Hospital from January 2010 to January 2020. The clinical characteristics, PHEX gene variants, as well as clinical outcome of the patients were summarized. To analyze the correlation between genotype and phenotype, the patients were divided into different subgroups according to the location of the variants, including N-terminal-located vs. C-terminal-located variant, and Zn-binding domain exon 17 or 19 variant vs. non-exon 17 or 19 variant. The age at onset, height standard deviation score (HtSDS), intercondylar or intermalleolar distance, fasting serum phosphorus, and HtSDS and intercondylar or intermalleolar distance at the final follow-up were compared by rank sum test or t text. Results: Among the 25 children with XLH, 8 were boys and 17 were girls. The median age of onset was 1.2 (1.0, 1.8) years, and the median age of diagnosis was 2.5 (1.5, 4.3) years. The main clinical manifestations were abnormal gait and lower limb deformity. The HtSDS was -2.0(-3.2, -0.8), and the intercondylar or intermalleolar distance was 4.5 (3.0, 6.0) cm. The fasting serum phosphorus level was 0.8 (0.7, 0.9) mmol/L, while the serum alkaline phosphatase level was (721±41) U/L and the serum calcium level was (2.5±0.1) mmol/L. Three patients (12%) had parathyroid hormone levels above the upper limit of the normal range. Twenty-five patients (100%) showed radiographic changes of active rickets. Nephrocalcinosis was found in 2 cases (9%). Twenty-four different PHEX variations were detected in 25 patients, among whom 11 (44%) had not been reported previously. No hot spot variation was found. No statistical differences (all P>0.05) were identified in clinical features and outcomes either in comparing patients with N-terminal (21 cases) and C-terminal (4 cases) variants, or in comparing patients with variant located in exon 17 or 19 (4 cases) or not (21 cases). Twenty-four cases (96%) were treated regularly with phosphate supplements and active vitamin D. After 2.7 (1.6, 5.0) years of follow-up, clinical symptoms were relieved in 96% (24/25) of the patients. The HtSDS after treatment had no significant difference compared to that before treatment (-2.0(-3.2, -0.8) vs.-2.0(-2.8, -1.1),Z =-0.156, P>0.05), while the intercondylar or intermalleolar distance after treatment was significantly reduced compared to that before treatment (4.5(3.0, 6.0) vs. 1.5(0, 3.3) cm, Z =-3.043, P<0.05). Bone X-rays were reexamined in 17 cases after treatment, and radiographic signs of rickets were improved. Eighteen cases had secondary hyperparathyroidism and 7 cases had nephrocalcinosis. Conclusions: The main clinical manifestations of XLH are abnormal gait, lower limb deformity and short stature. A high proportion of novel variations of PHEX gene but no hot spot variation neither genotype-phenotype correlation are found. Regular treatment with phosphate supplements and active vitamin D can significantly improve the symptoms except for the height. However, the rate of adverse events including secondary hyperparathyroidism and nephrocalcinosis seems to be high.
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Affiliation(s)
- L Y Wei
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - C X Gong
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - B Y Cao
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - X Q Li
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - X J Liang
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - W J Li
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - D Wu
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - M Liu
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - C Su
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - J J Chen
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
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Yang F, Chen L, Lai JM, Jian XE, Lv DX, Yuan LL, Liu YX, Liang FT, Zheng XL, Li XL, Wei LY, You WW, Zhao PL. Synthesis, biological evaluation, and structure-activity relationships of new tubulin polymerization inhibitors based on 5-amino-1,2,4-triazole scaffold. Bioorg Med Chem Lett 2021; 38:127880. [PMID: 33636303 DOI: 10.1016/j.bmcl.2021.127880] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/06/2021] [Accepted: 02/10/2021] [Indexed: 02/07/2023]
Abstract
Based on our previous research, thirty new 5-amino-1H-1,2,4-triazoles possessing 3,4,5-trimethoxyphenyl moiety were synthesized, and evaluated for antiproliferative activities. Among them, compounds IIa, IIIh, and IIIm demonstrated significant antiproliferative activities against a panel of tumor cell lines, and the promising compound IIIm dose-dependently caused G2/M phase arrest in HeLa cells. Furthermore, analogue IIa exhibited the most potent tubulinpolymerization inhibitory activity with an IC50 value of 9.4 μM, and molecular modeling studies revealed that IIa formed stable interactions in the colchicine-binding site of tubulin, suggesting that 5-amino-1H-1,2,4-triazole scaffold has potential for further investigation to develop novel tubulin polymerization inhibitors with anticancer activity.
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Affiliation(s)
- Fang Yang
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, PR China
| | - Lin Chen
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, PR China
| | - Jin-Mei Lai
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, PR China
| | - Xie-Er Jian
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, PR China
| | - Dong-Xin Lv
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, PR China
| | - Li-Li Yuan
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, PR China
| | - Yu-Xia Liu
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, PR China
| | - Feng-Ting Liang
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, PR China
| | - Xiao-Lan Zheng
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, PR China
| | - Xiong-Li Li
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, PR China
| | - Li-Yuan Wei
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, PR China
| | - Wen-Wei You
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, PR China
| | - Pei-Liang Zhao
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Science, Southern Medical University, Guangzhou 510515, PR China.
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Chen JJ, Gong CX, Wei LY, Cao BY, Wu D, Liu Y, Li WJ. [Diagnosis and follow-up of 2 cases of pediatric nephrogenic syndrome of inappropriate antidiuresis resulting from activating mutation in AVPR2 and literature review]. Zhonghua Er Ke Za Zhi 2021; 59:125-130. [PMID: 33548959 DOI: 10.3760/cma.j.cn112140-20200623-00660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To analyze the clinical and genetic features, as well as the treatment outcomes of two boys with nephrogenic syndrome of inappropriate antidiuresis (NSIAD) caused by gain-of-function mutations in the V2 vasopressin receptor gene (AVPR2). Methods: The clinical manifestations, genetic testing, therapeutic interventions and the outcomes of two boys with NSIAD hospitalized in the Department of Endocrinology, Beijing Children's Hospital in April 2019 were reported. A literature search with "Nephrogenic syndrome of inappropriate antidiuresis" and "AVPR2 gene" as keywords was conducted at the China national knowledge infrastructure (CNKI), the Wanfang Data Knowledge Service Platform, PubMed and Springer Link up to May 2020. Relevant published articles were reviewed. Results: The two cases presented with chronic and severe hyponatremia with hypo-osmolality, inappropriately elevated urinary osmolality and urinary sodium levels. The onset age was 5.25-years and 2 months respectively. AVPR2 sequencing revealed a previously described hemizygous activating mutation (c.409C>T, p.R137C) in both of boys, each inherited the variant from their mother. Patient 1 limited fluid intake by himself in his daily life, intravenous and oral sodium supplementations showed no significant increase of serum sodium level. Oral furosemide increased the serum sodium level and maintained it within normal range. The serum sodium and potassium levels were in the normal range during the 1-year follow-up period with oral furosemide. The serum sodium level of Patient 2 increased with restricting fluid intake and with salt supplementation. However, after he experienced respiratory infection, the plasma sodium level decreased. Subsequently, oral anti-infection medicine and furosemide were applied. The serum sodium level increased two days later and remained at a normal range afterwards. The boy was 1 year old with normal growth. He stopped taking furosemide after 4 months while taking 1 gram of salt per day, the blood sodium level maintained at normal range. Literature search identified no reports in Chinese journals, whereas 50 publications were found in English journals. A total of 30 NSIAD probands were reported and 16 of those (53%) had childhood onset, most presented with seizures. The majority had a hotspot change at the nucleotide position of 409 in AVPR2. Nine cases had an amino acid change as R137C and five cases as R137L. Fluid restriction and oral urea intake were main treatment options, no report so far was found with oral furosemide treatment. Conclusions: NSIAD presented with hyponatremia without any other specific presentations. Genetic testing for variants in AVPR2 is helpful for early diagnosis and timely treatment. The first two cases of oral furosemide treatment were reported by the article which helped to maintain a normal serum sodium level after limiting fluid intake and supplementing sodium which showed limited effect.
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Affiliation(s)
- J J Chen
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Centre for Children's Health, Beijing 100045, China
| | - C X Gong
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Centre for Children's Health, Beijing 100045, China
| | - L Y Wei
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Centre for Children's Health, Beijing 100045, China
| | - B Y Cao
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Centre for Children's Health, Beijing 100045, China
| | - D Wu
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Centre for Children's Health, Beijing 100045, China
| | - Y Liu
- Department of Pharmacy, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - W J Li
- Department of Endocrinology, Genetics and Metabolism, Beijing Children's Hospital, Capital Medical University, National Centre for Children's Health, Beijing 100045, China
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Ge CY, Wei LY, Tian Y, Wang HH. A Seven-NF-κB-Related Gene Signature May Distinguish Patients with Ulcerative Colitis-Associated Colorectal Carcinoma. Pharmgenomics Pers Med 2020; 13:707-718. [PMID: 33299340 PMCID: PMC7719442 DOI: 10.2147/pgpm.s274258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 11/11/2020] [Indexed: 01/07/2023]
Abstract
Purpose Ulcerative colitis (UC) patients have an increased risk of colorectal cancer (CRC), and compared with sporadic CRC, ulcerative colitis-associated colorectal cancer (CAC) is more aggressive with a worse prognosis. This study aimed to identify a gene signature to predict the risk of CAC for patients with UC in remission. Patients and Methods Series of quiescent UC-related transcriptome data obtained from the Gene Expression Omnibus (GEO) data set were divided into a training set and a validation set. Gene Set Variation Analysis (GSVA), Gene Set Enrichment Analysis (GSEA), and \Weighted Correlation Network Analysis (WGCNA) combined with protein-protein interaction (PPI) analysis were used to identify the pathways and gene signatures related to tumorigenesis among quiescent UC patients. A generalized linear model (GLM) of Poisson regression based on the training set was applied to estimate the diagnostic power of the gene signature in our validation set. Results The tumor necrosis factor (TNF) signaling via NF-κB pathway was significantly augmented with the highest normalized enrichment score (NES). The genes in the brown module from WGCNA have shown a significant correlation with CAC (Pearson coefficient = 0.83, p = 6e-06). A subset of NF-κB related genes (FOS, CCL4, CXCL1, MYC, CEBPB, ATF3, and JUNB) were identified with a relatively higher expression level in CAC samples. The diagnostic value of this 7-gene biomarker was estimated by the receiver operating characteristic (ROC) curve with an area under the ROC curve (AUC) at 0.82 (p<0.0001, 95% CI: 0.7098-0.9400) in the validation cohort. Conclusion In summary, the increased expression of this seven-NF-κB-related gene signature may act as a powerful index for tumorigenesis prediction among patients with UC in remission.
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Affiliation(s)
- Chao-Yi Ge
- Department of Gastroenterology, Peking University First Hospital, Beijing, People's Republic of China
| | - Li-Yuan Wei
- Department of Breast Surgery, Shanxi Bethune Hospital, Taiyuan, People's Republic of China
| | - Yu Tian
- Department of Gastroenterology, Peking University First Hospital, Beijing, People's Republic of China
| | - Hua-Hong Wang
- Department of Gastroenterology, Peking University First Hospital, Beijing, People's Republic of China
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Abstract
Metastatic breast involvement from extra-mammary neoplasms is unusual with a low incidence of 0.5% to 1.2% in clinical practice, 2.7% in cytological series, and 1.7% to 6.6% in autopsy series of all breast malignancies. Nearly 500 cases have been reported in small series and case reports. Gastric carcinoma rarely metastasizes to the breast. There are only 38 cases reported in PubMed. In this study, we present a case report of a 49-year-old woman who was diagnosed with right breast metastasis from a gastric carcinoma and undertake a literature review to pay attention to the diagnosis, treatment, and the prognosis of the disease.
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Affiliation(s)
- Li-Yuan Wei
- Department of Plastic Surgery, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Mei Kong
- Department of Pathology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Zhen Zhang
- Department of Oncology, Hangzhou Cancer Hospital, Hangzhou 310002, China
| | - Xiao-Chen Zhang
- Department of Oncology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China
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Iqbal MS, Iqbal MZ, Barua A, Veettil SK, Wei LY, Kit LW, Khan AH, Hussain Z, Iqbal MW. Pharmacoeconomic Evaluation and Burden of Illness of Acute Exacerbation of Copd in Patients in Malaysia. Value Health 2014; 17:A594. [PMID: 27202037 DOI: 10.1016/j.jval.2014.08.2046] [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] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- M S Iqbal
- Department of Clinical Pharmacy, Faculty of Pharmacy, AIMST University, Kedah, Malaysia
| | - M Z Iqbal
- Department of Clinical Pharmacy, Faculty of Pharmacy, AIMST University, Kedah, Malaysia
| | - A Barua
- Division of Community Medicine, School of Medicine, IMU, Bukit Jalil, Kuala Lumpur, Malaysia
| | - S K Veettil
- Department of Pharmacy Practice, School of Pharmacy, IMU, Bukit Jalil, Kuala Lumpur, Malaysia
| | - L Y Wei
- Department of Pharmacy Practice, School of Pharmacy, IMU, Bukit Jalil, Kuala Lumpur, Malaysia
| | - L W Kit
- Department of Pharmacy Practice, School of Pharmacy, IMU, Bukit Jalil, Kuala Lumpur, Malaysia
| | - A H Khan
- Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Universiti Sains Malaysia, Pulau Pinang,,,, Malaysia
| | - Z Hussain
- Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Universiti Sains Malaysia, Pulau Pinang,,,, Malaysia
| | - M W Iqbal
- Faculty of Law, Universiti Malaya,, Kualalumpur, Malaysia
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10
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Gruber HE, Ingram J, Norton HJ, Wei LY, Frausto A, Mills BG, Rude RK. Alterations in growth plate and articular cartilage morphology are associated with reduced SOX9 localization in the magnesium-deficient rat. Biotech Histochem 2009; 79:45-52. [PMID: 15223753 DOI: 10.1080/10520290410001697913] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [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: 10/26/2022] Open
Abstract
Insufficient dietary magnesium (Mg) intake has been associated with low bone mass in humans,and recent basic science studies have indicated that this bone loss may be secondary to increased release of substance P and TNFc Much less is known about the effects of low Mg intake on cartilage. We have evaluated growth plate and articular cartilage in rats following a 6 month dietary Mg restriction. Histomorphometry demonstrated significantly decreased distal femur articular cartilage chondrocyte density and decreased tibial growth plate width in experimental animals compared to controls. Growth plates of Mg-restricted animals showed reduced chondrocyte column formation. Extracellular matrix of both articular cartilage and growth plates in experimental animals contained reduced amounts of proteoglycans. Immunolocalization of Sox9 was decreased in both articular and growth plate cartilage in experimental animals compared to controls, suggesting that reduced Mg intake causes cartilage changes that may be secondary to reduced levels of the SOX9 transcription factor.
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Affiliation(s)
- H E Gruber
- Department of Orthopaedic Surgery, Carolinas Medical Center, Charlotte, North Carolina 28232, USA.
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11
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Lin CM, Wei LY, Wang TC. The delayed genotoxic effect of N-nitroso N-propoxur insecticide in mammalian cells. Food Chem Toxicol 2007; 45:928-34. [PMID: 17215065 DOI: 10.1016/j.fct.2006.11.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Revised: 11/08/2006] [Accepted: 11/27/2006] [Indexed: 10/23/2022]
Abstract
The N-nitroso derivative of an extensively used insecticide, propoxur, consistently induced dose-responsive chromosome aberrations and sister-chromatid exchanges (SCEs) in Chinese hamster ovary (CHO-W8) cells. Further investigations indicated that post-treatment incubation with a regular 1.5-cell-cycle period did not offer an unbiased estimation of the genotoxicity of N-nitroso carbamate insecticides. The scale of chromosome aberration induction increased with extension of the post-treatment incubation period. Comparable phenomena were not found in CHO-AGT cells proficient for O(6)-methylguanine-DNA-methyltransferase. In CHO-W8 cells, pulsed-treatment of the insecticide in the 1st replication cycle showed higher SCE induction than in the 2nd cycle. Similar phenomenon was also found in SCE induced by N-nitroso derivatives from other carbamate insecticides including aldicarb, carbofuran and methomyl. Treated cells did not show significantly perturbed cell cycle progression until 12 h after treatment removal. Based on the above observations, the O(6)-methylguanine-DNA adduct is suggested to be the major lesion caused by the delayed genotoxic effect of N-methyl carbamate insecticides as described in this report.
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Affiliation(s)
- Chih-Min Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan
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12
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Rude RK, Gruber HE, Norton HJ, Wei LY, Frausto A, Kilburn J. Reduction of dietary magnesium by only 50% in the rat disrupts bone and mineral metabolism. Osteoporos Int 2006; 17:1022-32. [PMID: 16601920 DOI: 10.1007/s00198-006-0104-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Accepted: 02/21/2006] [Indexed: 02/02/2023]
Abstract
INTRODUCTION The objective of this study was to determine the effect of a moderate reduction of dietary magnesium [50% of nutrient requirement (50% NR)] on bone and mineral metabolism in the rat, and to explore possible mechanisms for the resultant reduced bone mass. METHODS Female rats were 6 weeks of age at the start of study. Serum magnesium (Mg), calcium (Ca), parathyroid hormone (PTH), 1,25(OH)(2)-vitamin D, alkaline phosphatase, osteocalcin, and pyridinoline were measured during the study at 3- and 6-month time points in control (dietary Mg of 100% NR) and Mg-deficient animals (dietary Mg at 50% NR). Femurs and tibias were also collected for mineral content analyses, micro-computerized tomography, histomorphometry, and immunohistochemical localization of substance P, TNFalpha, and IL-1beta at 3 and 6 months. RESULTS Although no significant change in serum Mg was observed, Mg deficiency developed, as assessed by the reduction in bone Mg content at the 3- and 6-month time points (0.69+/-0.05 and 0.62+/-0.04% ash, respectively, in the Mg depletion group compared to 0.74+/-0.04 and 0.67+/-0.04% ash, respectively, in the control group; p=0.0009). Hypercalcemia did not develop. Although serum Ca level remained in the normal range, it fell significantly with Mg depletion at 3 and 6 months (10.4+/-0.3 and 9.6+/-0.3 mg/dl, respectively, compared to 10.5+/-0.4 and 10.1+/-0.6 mg/dl, respectively, in the control group; p=0.0076). The fall in serum Ca in the Mg-depleted animals was associated with a fall in serum PTH concentration between 3 and 6 months (603+/-286 and 505+/-302 pg/ml, respectively, although it was still higher than the control). The serum 1,25(OH)(2)-vitamin D level was significantly lower in the Mg depletion group at 6 months (10.6+/-7.1 pg/ml) than in the control (23.5+/- 12.7 pg/ml) (p<0.01 by the t-test). In Mg-deficient animals, no difference was noted in markers of bone turnover. Trabecular bone mineral content gain was less over time in the distal femur with Mg deficiency at 3 and 6 months (0.028+/-0.005 and 0.038+/-0.007 g, respectively, compared to 0.027+/-0.004 and 0.048+/-0.006 g, respectively, in the control group; p<0.005). Histomorphometry at these time points demonstrated decreased trabecular bone volume (15.76+/-1.93 and 14.19+/-1.85%, respectively, compared to 19.24+/-3.10 and 17.30+/-2.59%, respectively, in the control group; p=0.001). Osteoclast number was also significantly increased with Mg depletion (9.07+/-1.21 and 13.84+/-2.06, respectively, compared to 7.02+/-1.89 and 10.47+/-1.33, respectively, in the control group; p=0.0003). Relative to the control, immunohistochemical staining intensity of the neurotransmitter substance P and of the cytokines TNFalpha and IL-1beta was increased in cells of the bone microenvironment in the Mg depletion group, suggesting that inflammatory cytokines may contribute to bone loss. CONCLUSION These data demonstrate that Mg intake of 50% NR in the rat causes a reduced bone mineral content and reduced volume of the distal femur. These changes may be related to altered PTH and 1,25(OH)(2)-vitamin D formation or action as well as to an increase release of substance P and the inflammatory cytokines TNFalpha and IL-1beta.
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Affiliation(s)
- R K Rude
- University of Southern California and the Orthopaedic Hospital, 1975 Zonal Ave., GNH 6602, Los Angeles, CA 90089-9317, USA.
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13
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Abstract
PURPOSE To determine the effects of unilateral right/left nostril breathing (URNB/ULNB) and forced unilateral right/left nostril breathing (FURNB/FULNB) on intraocular pressure (IOP) and to examine the differences in the IOP during the various phases of nasal cycle. METHODS Young healthy volunteers of either sex aged between 19-24 years, participated in the sessions using URNB/ULNB (n = 52) and FURNB/FULNB (n = 28). The nostril dominance was calculated from signals recorded on the PowerLab equipment, representing pressure changes at the end of the nostrils during respiration. The IOP was measured with Tono-Pen. The subjects were divided into 4 groups viz. right nostril dominant (RND), left nostril dominant (LND), transitional right nostril dominant (TRND) and transitional left nostril dominant (TLND) groups. The IOP data 'before and after' URNB/ULNB or FURNB/FULNB were compared by using paired t-test. The baseline data of IOP between the groups were analysed by using independent samples t-test. RESULTS The URNB decreased the IOP in the LND and TLND (p < 0.01) and also in the RND (p < 0.05) groups but not significantly in the TRND group. The ULNB decreased the IOP in the RND group (p < 0.01) only. The FURNB significantly reduced the IOP (p < 0.05) only in the LND and RND groups. The FULNB decreased the IOP but not significantly. The baseline IOP did not differ significantly between the LND, RND, TLND and TRND groups. CONCLUSION The URNB/FURNB reduced the IOP, while ULNB/FULNB failed to increase the IOP significantly. It is suggested that the lowering of IOP by URNB indicated sympathetic stimulation.
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Affiliation(s)
- S M Mohan
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University Putra Malaysia, Serdang, Malaysia.
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14
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Rude RK, Gruber HE, Wei LY, Frausto A, Mills BG. Magnesium deficiency: effect on bone and mineral metabolism in the mouse. Calcif Tissue Int 2003; 72:32-41. [PMID: 12370796 DOI: 10.1007/s00223-001-1091-1] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2001] [Accepted: 02/08/2002] [Indexed: 11/25/2022]
Abstract
Insufficient dietary magnesium (Mg) intake has been associated in humans with low bone mass. Mg deficiency in the rat has suggested bone loss is due to increased bone resorption and/or inadequate bone formation during remodeling. The purpose of this study was to assess the effect of a low Mg diet on bone and mineral metabolism in the young and mature BALB/c mouse and explore the hypothesis that inflammatory cytokines may contribute to Mg deficiency-induced osteoporosis. Using an artificial diet, we induced targeted Mg depletion (0.002% Mg) with all other nutrients maintained at the normal level. In all Mg-depleted mice, hypomagnesemia developed and skeletal Mg content fell significantly. The serum Ca in Mg-deficient mice was higher than in control mice; however, serum PTH levels were not significantly different. Osteoprotegerin (OPG) in dosages that inhibit osteoclastic bone resorption did not prevent hypercalcemia in Mg-deficient animals. No significant difference in serum Ca was observed between groups when dietary Ca was reduced by 50%, suggesting that a compensatory increase in intestinal absorption might account for the hypercalcemia. Growth plate width decreased 33% in young Mg-deficient animals and chondrocyte columns decreased in number and length, suggesting that Mg deficiency reduced bone growth. Trabecular bone volume in the metaphysis of the tibia in these animals was decreased and osteoclast number was increased by 135%. Osteoblast number was significantly reduced. Immunohistochemistry revealed that substance P increased 230% and 200% in megakaryocytes and lymphocytes, respectively, after 1 day of Mg depletion. IL-1 increased by 140% in osteoclasts by day 3 and TNF alpha increased in osteoclasts by 120% and 500% in megakaryocytes on day 12. This study demonstrates a profound effect of Mg depletion on bone characterized by impaired bone growth, decreased osteoblast number, increased osteoclast number in young animals, and loss of trabecular bone with stimulation of cytokine activity in bone.
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Affiliation(s)
- R K Rude
- University of Southern California and the Orthopaedic Hospital, 2025 Zonal Ave., Los Angeles, CA 90033, USA.
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15
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Stöger M, Schattschneider P, Wei LY, Jouffrey B, Eisenmenger-Sittner C. Separation of pure elemental and oxygen influenced signal in ELNES. Ultramicroscopy 2002; 92:285-92. [PMID: 12213030 DOI: 10.1016/s0304-3991(02)00145-6] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The energy loss near edge structure (ELNES) of many elements is strongly influenced by the presence of oxygen or other elements at surfaces, grain boundaries, or in the bulk material. The presented investigation deals mainly with the influence of oxygen at the surface. A method for the separation of both, the pure bulk signal and the oxidized surface signal, was evaluated and tested on Al, Cu, Mg, and Si. A comparison of experimental data with ab initio bandstructure calculations and other proofs of the accuracy of ELNES separation are presented. Influences of error propagations were tested and are exemplarily given for Al and Si.
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Affiliation(s)
- M Stöger
- Institut für Festkörperphysik, Technische Universität Wien, Austria.
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16
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Chao JS, Wei LY, Huang MC, Liang SC, Chen HH. Genotoxic effects of triphenyltin acetate and triphenyltin hydroxide on mammalian cells in vitro and in vivo. Mutat Res 1999; 444:167-74. [PMID: 10477351 DOI: 10.1016/s1383-5718(99)00082-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [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: 11/23/2022]
Abstract
Two organotin pesticides, triphenyltin acetate (TPTA) and triphenyltin hydroxide (TPTH), were evaluated for their ability to induce micronuclei (MN) and sister chromatid exchange (SCE) in vitro using cultured Chinese hamster ovary (CHO) cells and in vivo BALB/c mouse erythrocytes. Both pesticides induced a dose-dependent increase but only TPTH induced a significant increase in MN at the highest dose (150 ng/ml) tested in CHO cells. With adding S9 microsomal fractions, both pesticides induced a meaningful MN induction at 150 ng/ml and a dose-dependent significant increase in SCE. In vivo MN induction in erythrocytes was conducted by treating BALB/c mice orally or intraperitoneally with these pesticides either in a single or triple treatments. Oral gavage (p.o.) of TPTA resulted in a dose-related significant increase of MN induction in peripheral blood and of TPTH induced a significant increase in micronucleated reticulocyte (MNRETs) only in a single treatment. Intraperitoneal administration of TPTA or TPTH, however, resulted in meaningless random increases in MN though these increases might be attributable to toxic effects. The MNRETs levels in the treatment with both pesticides were independent to the sampling time. This study demonstrated that TPTA and TPTH was potential chromosome mutagens.
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Affiliation(s)
- J S Chao
- National Laboratory Animal Breeding and Research Center, P.O. Box 1-86, Nankang 115, Taipei, Taiwan
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17
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Abstract
The objective of this work was to prepare for transmission electron microscopy (TEM) a layered structure of materials with fragile microstructure. The samples consisted of two layers of different materials, silicon nitride and borosilicate glass, loosely bonded together. The low strength of the sample resulted in fragmentation during more conventional preparation. However, it was possible to prepare the fragments by mounting them in a titanium specimen carrier with aluminium strips as support. After grinding and polishing, a technique of low-angle ion milling was used to obtain electron beam transparent areas at the nitride/glass interface.
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Affiliation(s)
- A K Westman
- Department of Material Science and Production Technology, Luleå University of Technology, Sweden.
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18
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Abstract
Recently (L. Y. Wei, M. J. Stutts, M. M. Hoffman, and P. D. Roepe. Biophys. J. 69: 883-895, 1996), 3T3 cells overexpressing the cystic fibrosis transmembrane conductance regulator (CFTR) were found to exhibit chemotherapeutic drug resistance and other traits of multidrug resistant (MDR) cells. In the present work, NIH 3T3/CFTR clones were selected with either doxorubicin or vincristine in incremental fashion to generate series of stable MDR cell lines that exhibit increasing levels of drug resistance. Thus C3D6 (grown in the presence of 600 nM doxorubicin) was selected from C3D4 (grown in the presence of 400 nM doxorubicin), which was selected from C3D1 (grown in the presence of 100 nM doxorubicin), which was in turn selected from the original 3T3/CFTR clone C3 (M. J. Stutts, S. E. Gabriel, J. C. Olsen, J. T. Gatzy, T. L. O'Connell, E. M. Price, and R. C. Boucher. J. Biol. Chem. 268: 20653-20658, 1993), which was not grown in the presence of chemotherapeutic drug. A similar series was generated via selection with vincristine. In both series, as well as series derived from a different CFTR clone, initial low-level drug selection increases CFTR expression without promoting MDR 1 or multidrug resistance-associated protein expression. On continued selection at higher drug concentrations, CFTR mRNA levels decrease while MDR 1 mRNA levels concomitantly increase. At each incremental step of selection, intracellular pH (pHi) increases (e.g., pHi of C3D6 > C3D4 > C3D1 > C3). Cl-/HCO3- exchange activity is significantly reduced in the drug-selected derivatives overexpressing MDR 1 but not the parental CFTR clones. The apparent set point of Na+/H+ exchange activity is significantly lower for the non-drug-selected 3T3/CFTR clones, relative to controls, but it increases on initial selection with chemotherapeutic drug. Overexpression of MDR 1 in the higher-level selectants does not appear to further perturb apparent Na+/H+ exchange. These data further describe how CFTR and MDR proteins may affect pHi regulation.
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Affiliation(s)
- L Y Wei
- Program in Molecular Pharmacology and Therapeutics, Raymond and Beverly Sackler Foundation Laboratory, Memorial Sloan-Kettering Cancer Center, New York, New York, USA
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19
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Abstract
This paper summarizes methods conventionally used to prepare thin foil samples of powder materials for transmission electron microscopy (TEM) and introduces another variant, ultramicrotomy, for the preparation of TEM samples of industrial dust powder. The choice of ultramicrotoming in the present work was based on two features of this technique: (1) it can produce thin-sectioned specimens with a uniform thickness; (2) it can retain the original elemental distribution in phases of the sample during sectioning. Dust powder preparation and the sectioning procedure are described in this paper. The results of the method are illustrated by examples of TEM/STEM micrographs of industrial dust.
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Affiliation(s)
- L Y Wei
- Department of Engineering Materials, Luleå University of Technology, Sweden
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20
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Wei LY, Chao JS, Hong CC. Assessment of the ability of propoxur, methomyl, and aldicarb, three carbamate insecticides, to induce micronuclei in vitro in cultured Chinese hamster ovary cells and in vivo in BALB/c mice. Environ Mol Mutagen 1997; 29:386-393. [PMID: 9212790] [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] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Three carbamate insecticides (propoxur, methomyl, and aldicarb) were evaluated for their ability to induce micronuclei (MN) in vitro using cultured Chinese hamster ovary (CHO) cells, and in vivo in mouse bone marrow erythrocytes. In vitro, all three insecticides induced a significant increase in micronucleated binucleate cells, which was generally both dose and sample time dependent. The in vivo studies involved treating male BALB/c mice by different routes, either once or on 3 consecutive days, followed by multiple or single sampling. Treatment by intraperitoneal injection or oral gavage induced a significant increase in micronucleated reticulocytes (MNRETs) in peripheral blood. For all three chemicals, the MN response depended on sample time and the number of treatments, while for aldicarb, the response depended also on the route of exposure. These positive results demonstrate that propoxur, methomyl, and aldicarb are capable of inducing structural and/or numerical chromosomal aberrations in mammalian cells either in vitro or in vivo. Furthermore, based on the results obtained, on optimal in vivo MN protocol for carbamate insecticides is a single treatment followed by blood sampling at 24 and 48 hr after treatment.
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Affiliation(s)
- L Y Wei
- National Laboratory Animal Breeding and Research Center, Nan-Kang, Taipei, Taiwan, Republic of China.
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21
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Abstract
Overexpression of the MDR protein, or p-glycoprotein (p-GP), in cells leads to decreased initial rates of accumulation and altered intracellular retention of chemotherapeutic drugs and a variety of other compounds. Thus, increased expression of the protein is related to increased drug resistance. Since several homologues of the MDR protein (CRP, ItpGPA, PDR5, sapABCDF) are also involved in conferring drug resistance phenomena in microorganisms, elucidating the function of the MDR protein at a molecular level will have important general applications. Although MDR protein function has been studied for nearly 20 years, interpretation of most data is complicated by the drug-selection conditions used to create model MDR cell lines. Precisely what level of resistance to particular drugs is conferred by a given amount of MDR protein, as well as a variety of other critical issues, are not yet resolved. Data from a number of laboratories has been gathered in support of at least four different models for the MDR protein. One model is that the protein uses the energy released from ATP hydrolysis to directly translocate drugs out of cells in some fashion. Another is that MDR protein overexpression perturbs electrical membrane potential (delta psi) and/or intracellular pH (pHi) and thereby indirectly alters translocation and intracellular retention of hydrophobic drugs that are cationic, weakly basic, and/or that react with intracellular targets in a pHi or delta psi-dependent manner. A third model proposes that the protein alternates between drug pump and Cl- channel (or channel regulator) conformations, implying that both direct and indirect mechanisms of altered drug translocation may be catalyzed by MDR protein. A fourth is that the protein acts as an ATP channel. Our recent work has tested predictions of these models via kinetic analysis of drug transport and single-cell photometry analysis of pHi, delta psi, and volume regulation in novel MDR and CFTR transfectants that have not been exposed to chemotherapeutic drugs prior to analysis. This paper reviews these data and previous work from other laboratories, as well as relevant transport physiology concepts, and summarizes how they either support or contradict the different models for MDR protein function.
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Affiliation(s)
- P D Roepe
- Molecular Pharmacology and Therapeutics Program, Raymond & Beverly Sackler Foundation Laboratory, Memorial Sloan Kettering Cancer Center, New York, New York, USA
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22
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Hoffman MM, Wei LY, Roepe PD. Are altered pHi and membrane potential in hu MDR 1 transfectants sufficient to cause MDR protein-mediated multidrug resistance? J Gen Physiol 1996; 108:295-313. [PMID: 8894978 PMCID: PMC2229331 DOI: 10.1085/jgp.108.4.295] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Multidrug resistance (MDR) mediated by overexpression of the MDR protein (P-glycoprotein) has been associated with intracellular alkalinization, membrane depolarization, and other cellular alterations. However, virtually all MDR cell lines studied in detail have been created via protocols that involve growth on chemotherapeutic drugs, which can alter cells in many ways. Thus it is not clear which phenotypic alterations are explicitly due to MDR protein overexpression alone. To more precisely define the MDR phenotype mediated by hu MDR 1 protein, we co-transfected hu MDR 1 cDNA and a neomycin resistance marker into LR73 Chinese hamster ovary fibroblasts and selected stable G418 (geneticin) resistant transfectants. Several clones expressing different levels of hu MDR 1 protein were isolated. Unlike previous work with hu MDR 1 transfectants, the clones were not further selected with, or maintained on, chemotherapeutic drugs. These clones were analyzed for chemotherapeutic drug resistance, intracellular pH (pHi), membrane electrical potential (Vm), and stability of MDR 1 protein overexpression. LR73/hu MDR 1 clones exhibit elevated pHi and are depolarized, consistent with previous work with LR73/mu MDR 1 transfectants (Luz, J.G. L.Y. Wei, S. Basu, and P.D. Roepe. 1994. Biochemistry. 33:7239-7249). The extent of these perturbations is related to the level of hu MDR 1 protein that is expressed. Cytotoxicity experiments with untransfected LR73 cells with elevated pHi due to manipulating percent CO2 show that the pHi perturbations in the MDR 1 clones can account for much of the measured drug resistance. Membrane depolarization in the absence of MDR protein expression is also found to confer mild drug resistance, and we find that the pHi and Vm changes can conceivably account for the altered drug accumulation measured for representative clones. These data indicate that the MDR phenotype unequivocally mediated by MDR 1 protein overexpression alone can be fully explained by the perturbations in Vm and pHi that accompany this overexpression. In addition, MDR mediated by MDR protein overexpression alone differs significantly from that observed for MDR cell lines expressing similar levels of MDR protein but also exposed to chemotherapeutic drugs.
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Affiliation(s)
- M M Hoffman
- Program in Molecular Pharmacology and Therapeutics, Raymond and Beverly Sackler Foundation Laboratory, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
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23
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Wei LY, Stutts MJ, Hoffman MM, Roepe PD. Overexpression of the cystic fibrosis transmembrane conductance regulator in NIH 3T3 cells lowers membrane potential and intracellular pH and confers a multidrug resistance phenotype. Biophys J 1995; 69:883-95. [PMID: 8519988 PMCID: PMC1236317 DOI: 10.1016/s0006-3495(95)79962-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [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: 01/31/2023] Open
Abstract
Because of the similarities between the cystic fibrosis transmembrane conductance regulator (CFTR) and multidrug resistance (MDR) proteins, recent observations of decreased plasma membrane electrical potential (delta psi) in cells overexpressing either MDR protein or the CFTR, and the effects of delta psi on passive diffusion of chemotherapeutic drugs, we have analyzed chemotherapeutic drug resistance for NIH 3T3 cells overexpressing different levels of functional CFTR. Three separate clones not previously exposed to chemotherapeutic drugs exhibit resistance to doxorubicin, vincristine, and colchicine that is similar to MDR transfectants not previously exposed to chemotherapeutic drugs. Two other clones expressing lower levels of CFTR are less resistant. As shown previously these clones exhibit decreased plasma membrane delta psi similar to MDR transfectants, but four of five exhibit mildly acidified intracellular pH in contrast to MDR transfectants, which are in general alkaline. Thus the MDR protein and CFTR-mediated MDR phenotypes are distinctly different. Selection of two separate CFTR clones on either doxorubicin or vincristine substantially increases the observed MDR and leads to increased CFTR (but not measurable MDR or MRP) mRNA expression. CFTR overexpressors also exhibit a decreased rate of 3H -vinblastine uptake. These data reveal a new and previously unrecognized consequence of CFTR expression, and are consistent with the hypothesis that membrane depolarization is an important determinant of tumor cell MDR.
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Affiliation(s)
- L Y Wei
- Program in Molecular Pharmacology and Therapeutics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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24
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Roepe PD, Weisburg JH, Luz JG, Hoffman MM, Wei LY. Novel Cl(-)-dependent intracellular pH regulation in murine MDR 1 transfectants and potential implications. Biochemistry 1994; 33:11008-15. [PMID: 7916210 DOI: 10.1021/bi00202a021] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [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: 01/27/2023]
Abstract
Previously [Luz et al. (1994) Biochemistry 33, 7239-7249], we determined that Cl(-)- and -HCO3-dependent pHi homeostasis was perturbed in multidrug resistant (MDR) cells created by transfecting LR73 Chinese hamster ovary fibroblasts with wild-type mu (murine) MDR 1 (Gros et al., 1991). Via single-cell photometry experiments performed under various conditions, we are now able to separate Na(+)-dependent and Na(+)-independent components of Cl-/-HCO3 exchange in the MDR transfectants and the parental LR73 cells. Cl(-)-dependent, Na(+)-independent reacidification of pHi, mediated by the anion exchanger 2 isoform in LR73 cells, is dramatically inhibited by mild overexpression of MDR protein. Analysis of H+ flux at different pHi shows that Cl(-)-dependent reacidification approaches 0.2 mM H+/s for LR73 cells at pHi = 8.0 but is at least 10-fold slower for MDR 1 transfectants that were never exposed to chemotherapeutics (EX4N7 cells). MDR 1 transfectants selected on the chemotherapeutic vinblastine (1-1 cells), which express approximately 10-fold more MDR protein relative to EX4N7 cells, exhibit similar behavior; however, alterations in Cl(-)-dependent pHi regulation are more severe. Hypotonic conditions, which have been shown to increase anomalous Cl- conductance in some cells overexpressing MDR protein (Valverde et al., 1992), are found to amplify the altered pHi homeostasis features in the primary transfectants that express lower levels of MDR protein such that they then mimic the behavior of the drug-selected cells that express substantially more MDR protein. Verapamil reverses the anomalous behavior.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- P D Roepe
- Program in Molecular Pharmacology & Therapeutics, Memorial Sloan-Kettering Cancer Center, New York, New York
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25
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Abstract
We have studied the effects of extracellular pH (pHo) and osmotic strength on the expression of the human multidrug resistance (MDR) protein. Both lowered pHo and hypertonic shock increase the level of hu MDR protein 5-10-fold in membranes isolated from the human colon carcinoma cell lines SW620 and HCT15 and the human kidney carcinoma line SKRC-39. Increased protein expression is dependent on the duration of acid or osmotic shock and is reversed within several days when normal growth conditions are restored. Quantitative northern blot analysis with a hu MDR 1 specific probe reveals increased MDR mRNA in the acid and hypertonically shocked cells. Interestingly, we find a greater increase in mRNA levels for hypotonically shocked colon cells, without an apparent increase in protein levels. Overexpressing cells are found to retain less [3H]vinblastine relative to cells cultured under normal conditions, and they are resistant to the cytotoxic effects of doxorubicin, vinblastine, and colchicine, but not methotrexate. This resistance appears to be reversed by treatment with verapamil. In contrast, SW620 cells previously induced to overexpress MDR protein via the administration of differentiation agents [Mickley et al. (1989) J. Biol. Chem. 264, 18031-18040] did not exhibit decreased retention of [3H]vinblastine; thus low-pHo-induced overexpression of MDR protein in these cells may provide additional factors that promote the full expression of the MDR phenotype. These data may help to explain why many solid tumors (e.g., of colon and kidney origin) develop MDR prior to chemotherapy, since they usually grow under similar acidic conditions. These data also support the contention that MDR protein may play a role in intracellular pH and volume homeostasis.
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Affiliation(s)
- L Y Wei
- Program in Molecular Pharmacology & Therapeutics, Memorial Sloan-Kettering Cancer Center, Cornell University, New York, New York 10021
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Abstract
We have used single-cell photometry to measure intracellular pH (pHi) for several MDR cell lines constructed by stably transfecting LR73 chinese hamster ovary fibroblasts with mutant and wild type murine MDR 1 genes. In addition, plasma membrane electrical potential (delta psi) has been measured for the same cells by the K+/valinomycin null point titration method using the ratiometric styryl probe di-4-ANEPPS. Both the untransfected, parental cell line and a cell line expressing substantial mutant MDR 1 protein (K432R/K1074R) that is unable to confer the MDR phenotype are found to have delta psi > or = -40 (+/- 5) mV and pHi < or = 7.16 (+/- 0.03) units. In contrast, MDR cell lines constructed by transfecting wild type mu MDR 1 cDNA are found to exhibit delta psi from 15 to 19 mV lower and pHi from 0.13 to 0.34 units higher. A cell line that overexpresses crippled MDR protein (S941F) that is not resistant to colchicine or doxorubicin, but which is resistant to vinblastine [Gros, P., Dhir, R., Croop, J., & Talbot, F. (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 7289-7293], exhibits elevated pHi and slightly elevated delta psi, relative to LR73. Northern and western blot analyses confirm the substantial overexpression of the mu MDR genes and proteins in these lines, as well as the mild overexpression of endogenous hamster p-GP mRNA in some lines. In general agreement with previous studies that examined myeloma cells overexpressing hu MDR 1 protein [Roepe, P.D., Wei, L.-Y., Cruz, J., & Carlson, D. (1993) Biochemistry 32, 11042-11056] we find that overexpression of wild type mu MDR 1 protein inhibits Cl(-)- and -HCO3-dependent pHi homeostasis. Via single-cell photometry studies we now conclude that this is due to inhibition of Na(+)-independent Cl-/-HCO3 exchange (strict anion exchange or AE). As concluded previously for other MDR cells, decreased AE activity is not due to decreased expression of the exchanger; in fact, again similar to previous work [Roepe et al. (1993) Biochemistry 32, 11042-11056], we find increased levels of AE mRNA in some MDR cell lines. Models that may explain these data that are also consistent with the known physiology of cells that endogenously express MDR protein are suggested. These data are consistent with a model for MDR protein function wherein overexpression of the protein decreases delta psi and/or elevates pHi via Cl(-)- and -HCO3-dependent mechanisms.
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Affiliation(s)
- J G Luz
- Program in Molecular Pharmacology & Therapeutics, Memorial Sloan-Kettering Cancer Center, Cornell University, New York, New York 10021
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Roepe PD, Wei LY, Cruz J, Carlson D. Lower electrical membrane potential and altered pHi homeostasis in multidrug-resistant (MDR) cells: further characterization of a series of MDR cell lines expressing different levels of P-glycoprotein. Biochemistry 1993; 32:11042-56. [PMID: 8105888 DOI: 10.1021/bi00092a014] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.2] [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: 01/28/2023]
Abstract
Recently [Roepe, P.D. (1992) Biochemistry 31, 12555-12564], increased steady-state levels of chemotherapeutic drug efflux from multidrug-resistant (MDR) myeloma cells were correlated with intracellular alkalinization. To better understand elevated pHi in MDR cells, Na(+)- and Cl-dependent recovery of pHi upon intracellular acid or alkaline shock has been examined for this same series of MDR cell lines. In agreement with another recent report [Boscoboinik, D., Gupta, R.S., & Epand, R.M. (1990) Br. J. Cancer 61, 568-572], we find that the rate of Na(+)-induced alkalinization after an intracellular acid shock is increased in the MDR cells, relative to the drug-sensitive parent. Interestingly, we also now find that mRNA encoding the human Na+/H+ exchanger (NHE) is overexpressed in these MDR cells, but the level of overexpression does not correlate with the relative drug resistance or steady-state pHi. It is also found that the efficiency of Cl(-)dependent reacidification of pHi, after an intracellular alkaline shock is reduced in the MDR cells. This effect appears to correlate with the relative expression of MDR protein, but not the relative expression of Cl-/HCO3- exchanger (AE), which we now find is also altered in the series of cells. Since elevated pHi will increase delta pH across the plasma membrane, we have also measured the electrical potential for these cells using three different methods. Most interestingly, the magnitude of the plasma membrane electrical potential (delta psi) decreases concomitant with increased expression of the MDR protein. Energy provided by increased delta pH compensates for the lowered delta psi, such that the total electrochemical membrane potential (delta mu H+) remains similar among the cells in this series (delta mu H+ = delta psi - Z delta pH). These data, along with other recent experiments that associated an increased Cl- conductance with the expression of MDR protein [Valverde, M., Diaz, M., Sepúlveda, F.V., Gill, D.R., Hyde, S.C., & Higgins, C.F. (1992) Nature 355, 830-833], are consistent with a model for MDR protein-mediated multidrug resistance that does not entail direct active transport of lipophilic drugs by the MDR protein.
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Affiliation(s)
- P D Roepe
- Program in Molecular Pharmacology & Therapeutics, Memorial Sloan-Kettering Cancer Center, New York, New York
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Abstract
A background level of sister-chromatid exchange (SCE) is found in mammalian cells. However, in the somatic cells of Drosophila melanogaster, there was no spontaneous SCE if a minimum concentration of bromodeoxyuridine (BrdU) was used. In this communication we report that in a mosquito (Aedes albopictus) cell line (C6/36), some cells also have no background SCE (0-SCE). Subclones of high (44%) or low (12%) frequency of 0-SCE cells were obtained, but none of them contained 100% 0-SCE cells. Increasing frequency of SCE/cell concomitant with decreasing frequency of 0-SCE cells was observed by raising the BrdU concentration in the culture medium during the first cell cycle, culturing cells at lower density and depleting reduced glutathione (GSH) with buthionine sulfoximine. Since these mosquito cells contain much higher level of GSH than Chinese hamster ovary (CHO) cells, and feeding cells with BrdU increased GSH in mosquito cells but decreased GSH in CHO cells, we speculate that GSH may play a role in the low or non-existent background SCE and in the high resistance to many DNA damaging agents of mosquito cells.
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Affiliation(s)
- L Y Wei
- Department of Entomology, National Chung-Hsing University, Taichung, Taiwan, Republic of China
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Abstract
An electronic diagnoser of the arterial pulse has been designed to give three outputs: pulse amplitude, instantaneous pulse rate (IPR) and spectral energy ratios (SER) at 5 and 10 Hz. The information thus provided will be useful for diagnosing many kinds of disease in the human body.
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Wei LY. Area utilization efficiency of a sloping heliostat system for solar concentration. Appl Opt 1983; 22:568-572. [PMID: 18195827 DOI: 10.1364/ao.22.000568] [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] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Area utilization efficiency (AUE) is formulated for a sloping heliostat system facing any direction. The effects of slope shading, incidence factor, sun shading, and tower blocking by the mirrors are all taken into account. Our results show that annually averaged AUEs calculated for heliostat systems (1) increase with tower height at low slope angles but less rapidly at high slopes, (2) increase monotonically with slope angle and saturate at large slopes for systems facing due south, (3) reach a maximum at a certain slope for systems facing other directions than due south, and (4) drop sharply at slopes greater than a certain value for systems facing due east or west due to slope shading effect. The results are useful for solar energy collection on nonflat terrains.
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Affiliation(s)
- L Y Wei
- University of Waterloo, Department of Electrical Engineering, Waterloo, Ontario N2L 3G1, Canada
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Abstract
A general formula is derived for the effective incidence factor of an array of heliostat mirrors for solar power collection. The formula can be greatly simplified for arrays of high symmetry and offers quick computation of the performance of the array. It shows clearly how the mirror distribution and locations affect the overall performance and thus provide a useful guidance for the design of a solar heliostat receiver system.
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Abstract
In this paper we present scientific advance in acupuncture based on electrical, neurophysiological, biochemical and therapeutic studies made inside and outside China since the early fifties. New modalities other than traditional needling techniques notably developed in Japan, France and Germany are described. For future prospects, efforts by making use of systems approach, field-body interaction, self-defense self-strategy and circadian rhythm are likely to produce great fruition in medicine. Possibilities of making advances in "three P's" medicine (preventive medicine, precision medicine and people medicine) by acupuncture are discussed.
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Abstract
The theoretical foundation of Chinese medicine as laid down in Hwang Ti Nei Ching is presented and interpreted here in modern language and conception. Our attempt is to bring Chinese medicine in harmony with Western science. Three Yin-Yang laws are formulated based on I Ching and Nei Ching and are justified from physics, mathematics and biology. The Wu-Hsing dynamic model is explained on the basis of dynamic interactions rather than static elements. The Ching-Lo doctrine is stressed upon its apparent correlations with the autonomic nervous system. Finally, the Chi is taken to play a role in life as the fields (gravitational, magnetic, nuclear, etc.) do in the physical world.
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Abstract
The electrical characteristics of lipid films with Au and Hg contacts were investigated. Our results indicate that the conduction is mainly electronic and is electrode limited. With gold biased negatively, the current-voltage characteristics of thin and thick films follow the equations: I = 4.367 exp [9.58(eV + 0.21)(1/2)]. [1 - exp (-eV/kT)]pA, and I = 3.424 exp [8.59(eV + 0.082)(1/2)][1 - exp (-eV/kT)]pA, respectively. For thick films, the conductivity is insensitive to thickness. By temperature and photoresponse measurements the interface barrier height is found to be 1.09 eV. In view of the possible structural disorders in the films, a model is proposed to explain our findings based on the theory of noncrystalline materials. According to this model, the band gap for the film is 2.016 eV and the density of localized states is near the Fermi level, 1.31 x 10(18) cm(-3) eV(-1). The results may be helpful in providing some insight into the speculated electronic conduction in biological membranes.
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Abstract
EXACT FORMULAS ARE DERIVED FOR THE ENERGY CHANGE OF A DIPOLE SYSTEM WITH TWO ENERGY STATES (OR BANDS) IN A CHANGING FIELD IN TWO CASES: (a) no dipole flip-flop and (b) dipole flip-flop caused by stimulation. Based on these formulas, the positive and negative heats are calculated. The results are in good agreement with experiment in case b but are 60-180% larger in case a. Furthermore, the theory shows that the negative heat cannot be less than the positive heat in case a but can be either way in case b, the latter result being found prevalent in experiment. It is concluded that nerve excitation is most likely to involve dipole flip-flop at the membrane surface. The theory is consistent in the interpretations and correlations of the electrical, optical, and thermal effects observed in nerve axon.
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Wei LY. Sodium current flow in excitable membranes. Biophys J 1971; 11:629-30. [PMID: 5089919 PMCID: PMC1483976 DOI: 10.1016/s0006-3495(71)86241-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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Abstract
Based on theory and experiment, we found that the conduction through the oxide film in Lillie's iron-wire model is dominated by Schottky emission at low fields (below 10(6) v/cm), by electron tunneling from trap to trap at intermediate fields and by direct tunneling (Fowler-Nordheim type) at higher fields (above 3 x 10(6) v/cm). The trap-to-trap tunneling is considered to give rise to the negative resistance and the fixed position of the current maximum as observed. Some of the nervelike properties of the Lillie's model are interpreted on this tunneling mechanism.
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Abstract
A physical model of nerve excitation and conduction is proposed based on the discovery of three new axon membrane properties: the negative fixed surface charge, the birefringence change, and the infrared emission.
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Abstract
In this paper we propose that chemicals such as acetylcholine are electric dipoles which when oriented and arranged in a large array could produce an electric field strong enough to drive positive ions over the junction barrier of the post-synaptic membrane and thus initiate excitation or produce depolarization. This theory is able to explain a great number of facts such as cleft size, synaptic delay, nonregeneration, subthreshold integration, facilitation with repetition, and the calcium and magnesium effects. It also shows why and how acetylcholine could act as excitatory or inhibitory transmitters under different circumstances. Our conclusion is that the nature of synaptic transmission is essentially electrical, be it mediated by electrical or chemical transmitters.
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