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Li Z, Zeng CM, Dong YG, Cao Y, Yu LY, Liu HY, Tian X, Tian R, Zhong CY, Zhao TT, Liu JS, Chen Y, Li LF, Huang ZY, Wang YY, Hu Z, Zhang J, Liang JX, Zhou P, Lu YQ. A segmentation model to detect cevical lesions based on machine learning of colposcopic images. Heliyon 2023; 9:e21043. [PMID: 37928028 PMCID: PMC10623278 DOI: 10.1016/j.heliyon.2023.e21043] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 10/12/2023] [Accepted: 10/13/2023] [Indexed: 11/07/2023] Open
Abstract
Background Semantic segmentation is crucial in medical image diagnosis. Traditional deep convolutional neural networks excel in image classification and object detection but fall short in segmentation tasks. Enhancing the accuracy and efficiency of detecting high-level cervical lesions and invasive cancer poses a primary challenge in segmentation model development. Methods Between 2018 and 2022, we retrospectively studied a total of 777 patients, comprising 339 patients with high-level cervical lesions and 313 patients with microinvasive or invasive cervical cancer. Overall, 1554 colposcopic images were put into the DeepLabv3+ model for learning. Accuracy, Precision, Specificity, and mIoU were employed to evaluate the performance of the model in the prediction of cervical high-level lesions and cancer. Results Experiments showed that our segmentation model had better diagnosis efficiency than colposcopic experts and other artificial intelligence models, and reached Accuracy of 93.29 %, Precision of 87.2 %, Specificity of 90.1 %, and mIoU of 80.27 %, respectively. Conclution The DeepLabv3+ model had good performance in the segmentation of cervical lesions in colposcopic post-acetic-acid images and can better assist colposcopists in improving the diagnosis.
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Affiliation(s)
- Zhen Li
- Department of Gynecological Oncology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, 430071, China
| | - Chu-Mei Zeng
- Department of Obstetrics and gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510062, China
| | - Yan-Gang Dong
- Institute for Brain Research and Rehabilitation, the South China Normal University, Guangzhou, Guangdong, 510631, China
| | - Ying Cao
- Department of Obstetrics and Gynecology, Academician expert workstation, The Central Hospital of Wuhan, Tongji Medical College Huazhong University of Science and Technology, Wuhan, Hubei, 430014, China
| | - Li-Yao Yu
- Department of Obstetrics and Gynecology, Academician expert workstation, The Central Hospital of Wuhan, Tongji Medical College Huazhong University of Science and Technology, Wuhan, Hubei, 430014, China
| | - Hui-Ying Liu
- Department of Obstetrics and gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510062, China
| | - Xun Tian
- Department of Obstetrics and Gynecology, Academician expert workstation, The Central Hospital of Wuhan, Tongji Medical College Huazhong University of Science and Technology, Wuhan, Hubei, 430014, China
| | - Rui Tian
- the Generulor Company Bio-X Lab, Zhuhai, Guangdong, 519060, China
| | - Chao-Yue Zhong
- the Generulor Company Bio-X Lab, Zhuhai, Guangdong, 519060, China
| | - Ting-Ting Zhao
- the Generulor Company Bio-X Lab, Zhuhai, Guangdong, 519060, China
| | - Jia-Shuo Liu
- Department of Obstetrics and gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510062, China
| | - Ye Chen
- Department of Obstetrics and gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510062, China
| | - Li-Fang Li
- Department of Obstetrics and gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510062, China
| | - Zhe-Ying Huang
- Department of Obstetrics and gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510062, China
| | - Yu-Yan Wang
- Department of Obstetrics and gynecology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510062, China
| | - Zheng Hu
- Department of Gynecological Oncology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, 430071, China
| | - Jingjing Zhang
- Department of Gynecological Oncology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, 430071, China
| | - Jiu-Xing Liang
- Institute for Brain Research and Rehabilitation, the South China Normal University, Guangzhou, Guangdong, 510631, China
| | - Ping Zhou
- Department of Gynecology, Dongguan Maternal and Child Hospital, Dongguan, Guangdong, 523057, China
| | - Yi-Qin Lu
- Department of Gynecology, Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, 101121, China
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Zhang YM, Zhang XR, Shao SM, Liu J, Zeng CM, Han Y. [A case of neonatal hereditary spherocytosis characterized by hydrops fetalis]. Zhonghua Er Ke Za Zhi 2020; 58:418-420. [PMID: 32392960 DOI: 10.3760/cma.j.cn112140-20200113-00030] [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: 06/11/2023]
Affiliation(s)
- Y M Zhang
- Department of Pediatrics, Peking University People's Hospital, Beijing 100044, China
| | - X R Zhang
- Department of Pediatrics, Peking University People's Hospital, Beijing 100044, China
| | - S M Shao
- Department of Pediatrics, Peking University People's Hospital, Beijing 100044, China
| | - J Liu
- Department of Pediatrics, Peking University People's Hospital, Beijing 100044, China
| | - C M Zeng
- Department of Pediatrics, Peking University People's Hospital, Beijing 100044, China
| | - Y Han
- Department of Pediatrics, Peking University People's Hospital, Beijing 100044, China
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Xiong DD, Zeng CM, Jiang L, Luo DZ, Chen G. Ki-67/MKI67 as a Predictive Biomarker for Clinical Outcome in Gastric Cancer Patients: an Updated Meta-analysis and Systematic Review involving 53 Studies and 7078 Patients. J Cancer 2019; 10:5339-5354. [PMID: 31632479 PMCID: PMC6775696 DOI: 10.7150/jca.30074] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 06/12/2019] [Indexed: 12/18/2022] Open
Abstract
Gastric cancer (GC) threatens human health worldwide and we performed this meta-analysis to evaluate the clinical value of Ki-67/MKI67 in patients with GC. The combined hazard ratio (HR), odds ratio (OR) and 95% confidence interval (95% CI) were calculated to assess the relationships of Ki-67/MKI67 expression with prognoses and clinicopathological characteristics. Genes co-expressed with MKI67 were collected for Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and protein-protein interaction (PPI) network analyses. In total, 53 studies with 7078 patients were included in this study. The pooled HRs indicated that an elevated expression of Ki-67/MKI67 predicted an unfavorable overall survival (HR: 1.54, 95% CI: 1.33-1.78, P<0.0001) and disease-free survival (HR: 2.28, 95% CI: 1.43-3.64, P<0.0001) in GC patients. Additionally, in patients with advanced GC, a high Ki-67/MKI67 expression was also significantly connected with OS (HR: 1.37, 95% CI: 1.18-1.60, P<0.0001). The combined ORs showed that Ki-67/MKI67 expression was related to TNM stage (stage III/IV versus stage I/II: OR=1.93, 95% CI=1.34-2.78, P<0.0001), tumor differentiation (poor versus well/moderate: OR=1.94, 95% CI=1.32-2.85, P=0.001), lymph node metastasis (yes versus no: OR=1.67, 95% CI=1.23-2.25, P=0.001), distant metastasis (yes versus no: OR=1.67, 95% CI=1.24-2.26, P=0.001) and tumor invasion depth (T3/T4 versus Tis/T1/T2: OR=1.98, 95% CI=1.60-2.44, P<0.0001). The results of GO, KEGG pathway and PPI network analyses indicated that Ki-67/MKI67 may be involved in the development of GC via influencing P53 signaling pathway. Ki-67/MKI67 could be a potential indicator to predict the prognosis of patients with GC and identify high-risk cases. Detecting Ki-67/MKI67 expression in clinic may be helpful in optimizing individual treatment and further improving the survival expectancy of patients with GC.
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Affiliation(s)
- Dan-Dan Xiong
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, China
| | - Chu-Mei Zeng
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, China
| | - Ling Jiang
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, China
| | - Dian-Zhong Luo
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, China
| | - Gang Chen
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, China
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Ding H, Ye ZH, Wen DY, Huang XL, Zeng CM, Mo J, Jiang YQ, Li JJ, Cai XY, Yang H, Chen G. Downregulation of miR‑136‑5p in hepatocellular carcinoma and its clinicopathological significance. Mol Med Rep 2017; 16:5393-5405. [PMID: 28849100 PMCID: PMC5647073 DOI: 10.3892/mmr.2017.7275] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 06/12/2017] [Indexed: 12/11/2022] Open
Abstract
The clinical significance of microRNA (miR)‑136‑5p in hepatocellular carcinoma (HCC) has not been verified. Therefore, in the current study, the authors aimed to explore miR‑136‑5p expression and its clinical significance in HCC, as well as to investigate its potential target genes function. The authors detected the levels of miR‑136‑5p in 101 pairs of HCC and para‑cancer tissues via reverse transcription‑quantitative polymerase chain reaction. Gene Expression Omnibus database and the Cancer Genome Atlas (TCGA) database were used to further verify the clinical significance of miR‑136‑5p expression in HCC. The target genes prediction analysis of miR‑136‑5p, natural language processing (NLP) analysis of HCC in PubMed and gene functional enrichment analysis were conducted. The miR‑136‑5p level was markedly downregulated in HCC tissue, compared to para‑non‑tumor tissue. MiR‑136‑5p expression decreased in HCC patients with metastasis (P=0.004), advance TNM stage (P<0.001), portal vein tumor embolus (P=0.007) and vaso‑invasion (P=0.003), compared with those HCC patients with non‑metastasis, early TNM stage, non‑portal vein tumor embolus and non‑vaso‑invasion, respectively. In the TCGA database, downregulated miR‑136‑5p was also observed in HCC tissue compared to normal liver tissue (P<0.001). There were 178 genes obtained from the overlap between predicted targets and NLP analysis. GO and KEGG pathway analyses revealed some significant pathways related to cancers. Downregulation of miR‑136‑5p may be responsible for the carcinogenesis and aggressiveness of HCC. miR‑136‑5p may act as an anti‑carcinoma miRNA, which is essential for HCC progression through the regulation of various signaling pathways. Thus, miR‑136‑5p interaction may provide a novel strategy for HCC treatment.
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Affiliation(s)
- Hua Ding
- Department of Radiotherapy, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China
| | - Zhi-Hua Ye
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China
| | - Dong-Yue Wen
- Department of Medical Ultrasonics, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China
| | - Xiao-Liang Huang
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China
| | - Chu-Mei Zeng
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China
| | - Jie Mo
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China
| | - Yi-Qiang Jiang
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China
| | - Jian-Jun Li
- Department of General Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China
| | - Xiao-Yong Cai
- Department of General Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China
| | - Hong Yang
- Department of Medical Ultrasonics, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China
| | - Gang Chen
- Department of Pathology, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, P.R. China
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Mennerick S, Zeng CM, Benz A, Shen W, Izumi Y, Evers AS, Covey DF, Zorumski CF. Effects on gamma-aminobutyric acid (GABA)(A) receptors of a neuroactive steroid that negatively modulates glutamate neurotransmission and augments GABA neurotransmission. Mol Pharmacol 2001; 60:732-41. [PMID: 11562435] [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: 02/21/2023] Open
Abstract
Neurosteroids positively and negatively modulate gamma-aminobutyric acid (GABA)(A) receptors and glutamate receptors, which underlie most fast inhibition and excitation in the central nervous system. We report the identification of a neuroactive steroid, (3 alpha,5 beta)-20-oxo-pregnane-3-carboxylic acid (3 alpha 5 beta PC), with unique cellular actions. 3 alpha 5 beta PC positively modulates GABA(A) receptor function and negatively modulates N-methyl-D-aspartate (NMDA) receptor function, a combination that may be of particular clinical benefit. 3 alpha 5 beta PC promotes net GABA(A) potentiation at low steroid concentrations (<10 microM) and at negative membrane potentials. At higher concentrations, the steroid also blocks GABA receptors. Because this block would presumably counteract the NMDA receptor blocking actions of 3 alpha 5 beta PC, we characterize the GABA receptor block in some detail. Agonist concentration, depolarization, and high extracellular pH increase the block. The apparent pK for both potentiation and block was 6.4 to 6.9, substantially higher than expected from carboxylated steroid in an aqueous environment. Block is not dependent on the stereochemistry of the carboxylic acid at carbon 3 and is relatively insensitive to placement of the carboxylic acid at the opposite end of the steroid (carbon 24). Potentiation is critically dependent on the stereochemistry of the carboxylic acid group at carbon 3. Consistent with the pH dependence of potentiation, effects of the amide derivative (3 alpha,5 beta)-20-oxo-pregnane-3-carboxamide, suggest that the un-ionized form of 3 alpha 5 beta PC is important for potentiation, whereas the ionized form is probably responsible for block. Further refinement of the neuroactive steroid to promote GABA potentiation and NMDA receptor block and diminish GABA receptor block may lead to a clinically useful neuroactive steroid.
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Affiliation(s)
- S Mennerick
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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Gottschalk I, Lundqvist A, Zeng CM, Hägglund CL, Zuo SS, Brekkan E, Eaker D, Lundahl P. Conversion between two cytochalasin B-binding states of the human GLUT1 glucose transporter. Eur J Biochem 2000; 267:6875-82. [PMID: 11082199 DOI: 10.1046/j.1432-1033.2000.01788.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Two cytochalasin B-binding states of the human red blood cell facilitative glucose transporter GLUT1 were studied, one exhibiting one cytochalasin B-binding site on every second GLUT1 monomer (state 1) and the other showing one site per monomer (state 2). Quantitative affinity chromatography of cytochalasin B was performed on (a) biotinylated red blood cells, (b) cytoskeleton-depleted red blood cell membrane vesicles, and (c) GLUT1 proteoliposomes. The cells were adsorbed on streptavidin-derivatized gel beads, and the vesicles and proteoliposomes entrapped in dextran-grafted agarose gel beads. Cytochalasin B binding to free vesicles and proteoliposomes was analyzed by Hummel and Dreyer size-exclusion chromatography and ultracentrifugation. Analysis of the biotinylated cells indicated an equilibrium between the two GLUT1 states. GLUT1 in free membrane vesicles attained state 2, but was converted into state 1 on entrapment of the vesicles. Purification of GLUT1 in the presence of non-ionic detergent followed by reconstitution produced GLUT1 in state 1. This state was maintained after entrapment of the proteoliposomes. Finally, GLUT1 showed slightly higher affinity for cytochalasin B in state 1 than in state 2. In summary, the cytochalasin B-binding state of GLUT1 seemed to be affected by (a) biotinylation of the cell surface, (b) removal of the cytoskeleton at high pH and low ionic strength, (c) interaction between the dextran-grafted agarose gel matrix and the membrane vesicles, and (d) reconstitution to form proteoliposomes.
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Affiliation(s)
- I Gottschalk
- Department of Biochemistry, Biomedical Center, Uppsala University, Sweden
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Pu Y, Li QF, Zeng CM, Gao J, Qi J, Luo DX, Mahankali S, Fox PT, Gao JH. Increased detectability of alpha brain glutamate/glutamine in neonatal hypoxic-ischemic encephalopathy. AJNR Am J Neuroradiol 2000; 21:203-12. [PMID: 10669252 PMCID: PMC7976324] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/1999] [Accepted: 07/30/1999] [Indexed: 02/15/2023]
Abstract
BACKGROUND AND PURPOSE Proton MR spectroscopy (MRS) detectability of brain glutamate/glutamine (Glx) is increased in hypoxic-ischemic insults and is implicated in the neuronal injury and death that follows. Our aim was to correlate the proton MRS detectability of alpha-CH protons of Glx (alpha-Glx) with the Sarnat stage of neonatal hypoxic-ischemic encephalopathy (HIE). METHODS Initial and follow-up proton MRS studies at 1.9 T were performed in 28 neonates aged 1 to 7 days (seven healthy control subjects and 21 with HIE: 10 mild, nine moderate, and two severe) and in 12 neonates aged 13 to 17 days (12 with HIE: eight mild, three moderate, and one severe), respectively. Both point-resolved spectroscopy (PRESS) and stimulated-echo acquisition mode (STEAM) sequences were used. The spectral volume of interest was in the basal ganglia, thalami, and adjoining regions. The detectability of alpha-Glx was assessed by two different parameters: the detection rate of the alpha-Glx peak and the peak-area ratio of alpha-Glx to creatine and phosphocreatine. RESULTS On both the initial and follow-up PRESS studies, all the neonates with moderate and severe HIE showed an alpha-Glx peak, compared with one healthy control subject in the initial study and one neonate with mild HIE in both the studies. They also demonstrated a significantly higher peak-area ratio of alpha-Glx/(creatine and phosphocreatine) on both the initial and follow-up studies. The peak-area ratios in neonates with HIE positively correlated with the Sarnat stage of HIE on both the initial and follow-up studies. Neonates with moderate and severe HIE also showed a consistently higher alpha-Glx peak on both the initial and follow-up studies with the STEAM sequence. CONCLUSION Proton MRS detectability of alpha-Glx is increased in moderate and severe HIE and correlates with the Sarnat stage of HIE.
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Affiliation(s)
- Y Pu
- The People's Hospital of The Beijing Medical University, The People's Republic of China
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Lundahl P, Zeng CM, Lagerquist Hägglund C, Gottschalk I, Greijer E. Chromatographic approaches to liposomes, proteoliposomes and biomembrane vesicles. J Chromatogr B Biomed Sci Appl 1999; 722:103-20. [PMID: 10068136 DOI: 10.1016/s0378-4347(98)00370-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Size-exclusion chromatography has been used for fractionation of liposomes, proteoliposomes and biomembrane vesicles of up to approximately 500 nm in size and for separation of these entities from smaller components. Liposome sizes, encapsulation stability, and solute affinities for membrane proteins have been determined. Counter-current distribution in aqueous two-phase systems has widened the range of applications to larger structures. Immobilized biomembrane vesicles and (proteo)liposomes provide stationary phases for chromatographic analysis of specific or nonspecific membrane-solute interactions.
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Affiliation(s)
- P Lundahl
- Department of Biochemistry, Biomedical Center, Uppsala University, Sweden
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Haneskog L, Zeng CM, Lundqvist A, Lundahl P. Biomembrane affinity chromatographic analysis of inhibitor binding to the human red cell nucleoside transporter in immobilized cells, vesicles and proteoliposomes. Biochim Biophys Acta 1998; 1371:1-4. [PMID: 9565649 DOI: 10.1016/s0005-2736(98)00008-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The affinity of the human red cell nucleoside transporter for the transport inhibitor nitrobenzylthioinosine decreases upon protein purification. The affinity was highest for the whole cells (Kd, 0.04 nM), lowered upon cytoskeleton depletion (Kd, 0.2 nM) and lowest after partial purification and reconstitution (Kd, 0.3 nM), as determined by frontal affinity chromatography.
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Affiliation(s)
- L Haneskog
- Department of Biochemistry, Biomedical Center, Uppsala University, Box 576, S-751 23 Uppsala, Sweden
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10
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Lu L, Lundqvist A, Zeng CM, Lagerquist C, Lundahl P. D-Glucose, forskolin and cytochalasin B affinities for the glucose transporter Glut1. Study of pH and reconstitution effects by biomembrane affinity chromatography. J Chromatogr A 1997; 776:81-6. [PMID: 9286080 DOI: 10.1016/s0021-9673(97)00151-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [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: 02/05/2023]
Abstract
The affinities of D-glucose and the transport inhibitors, forskolin and cytochalasin B (CB), for Glut1 were studied by frontal affinity chromatography at pH 5-10 on sterically immobilized proteoliposomes with reconstituted human red cell glucose transporter Glut1. The affinity of D-glucose for Glut1 became slightly weaker as the pH was increased. The inhibitor affinities decreased and became immeasurably weak above pH 9. At pH 7.4, the dissociation constants were 44 mM for glucose, 1.8 microM for forskolin and 72 nM for CB. The affinities of these solutes for Glut1 in red cell membrane vesicles and particularly for Glut1 in red cells were higher, as shown by chromatographic analyses.
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Affiliation(s)
- L Lu
- Department of Biochemistry, Uppsala University, Sweden
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Zeng CM, Zhang Y, Lu L, Brekkan E, Lundqvist A, Lundahl P. Immobilization of human red cells in gel particles for chromatographic activity studies of the glucose transporter Glut1. Biochim Biophys Acta 1997; 1325:91-8. [PMID: 9106486 DOI: 10.1016/s0005-2736(96)00247-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Chromatography on a novel stationary phase, human red cells immobilized in a gel bed, was introduced for analysis of activities of the glucose transporter Glut1 in the cell membrane. A gel containing positively charged ligands was synthesized from derivatized acrylamide monomers. Red cells were immobilized in gel particles which were packed into a column tube for chromatographic analyses over periods of 10-15 days. D-Glucose was separated from L-glucose on a 1.1-ml bed with a retention volume difference of 0.23 ml, approximately equal to the total inner volume of immobilized intact cells and of ghosts probably formed from lysed cells during the immobilization. The separation was suppressed by the glucose-transport inhibitor cytochalasin B. The interactions between D-glucose, the transport inhibitor forskolin and Glut1 were analyzed by quantitative frontal affinity chromatography. The dissociation constants at room temperature were 6.8 mM for D-glucose binding and 1.8 microM for glucose-displaceable binding of forskolin, in good agreement with published values. The results suggest that chromatography on immobilized cells is a potentially useful tool for studies on cellular membrane functions.
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Affiliation(s)
- C M Zeng
- Department of Biochemistry, Uppsala University, Sweden
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Zhang Y, Zeng CM, Li YM, Hjertén S, Lundahl P. Immobilized liposome chromatography of drugs on capillary continuous beds for model analysis of drug-membrane interactions. J Chromatogr A 1996; 749:13-8. [PMID: 8921592 DOI: 10.1016/0021-9673(96)00432-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [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: 02/03/2023]
Abstract
Liposomes were immobilized in capillary continuous beds with covalently linked C4 or C8 alkyl ligands for chromatographic analysis of drug interaction with phospholipid bilayers, as reflected by drug retention volumes and calculated differences in interaction free energies. This procedure is a high-resolution micro-scale version of immobilized liposome chromatography for prediction of diffusion of drugs across biological membranes. The logarithm of the specific capacity factors of several structurally unrelated drugs showed a linear correlation with the logarithm of known apparent drug permeabilities through Caco-2 epithelial cell monolayers. The latter values are used for prediction of absorption of orally administered drug doses.
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Affiliation(s)
- Y Zhang
- Department of Biochemistry, Uppsala University, Sweden
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Abstract
Continuous beds have been used as matrices for cation- and anion-exchange chromatography of proteins on columns with an i.d. in the range of 0.005-0.015 mm. On-tube uv detection is not feasible at low protein concentrations with these narrow-bore columns. Therefore, a more sensitive detection system has been developed based on blotting technique: as the protein zones leave the microcolumn chromatographically they become adsorbed onto a rotating polyvinylidene difluoride blotting membrane. The protein spots can then be visualized by means of Coomassie brilliant blue, immunomethods, and other standard techniques. By using an immunomethod 0.015 ng of human transferrin can easily be detected. The blotting membrane can be washed with water without loss of adsorbed protein. This is an attractive feature because the presence of salts, etc., diminishes the accuracy in the determination of molecular weights of proteins by mass spectrometry. The microcolumns are easy to prepare. A solution of appropriate monomers is sucked into a piece of fused silica tubing. The rod formed upon polymerization contains channels through which the eluent can pass. No supporting frit is required because the polymer rod is anchored by covalent bonds to the tubing wall.
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Affiliation(s)
- J L Liao
- Department of Biochemistry, Uppsala University, Sweden
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Zeng CM, Ishibashi M, Kobayashi J. Biemnasterol, a new cytotoxic sterol with the rare 22,25-diene side chain, isolated from the marine sponge Biemna sp. J Nat Prod 1993; 56:2016-2018. [PMID: 8289069 DOI: 10.1021/np50101a027] [Citation(s) in RCA: 11] [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] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Biemnasterol [2], a new sterol with a 22,25-diene side chain possessing cytotoxic activity, has been isolated from the Okinawan marine sponge Biemna sp. and the structure elucidated on the basis of spectroscopic data and chemical means.
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Affiliation(s)
- C M Zeng
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
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Kobayashi J, Zeng CM, Ishibashi M, Sasaki T. Luffariolides F and G, new manoalide derivatives from the Okinawan marine sponge Luffariella sp. J Nat Prod 1993; 56:436-439. [PMID: 8482949 DOI: 10.1021/np50093a020] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- J Kobayashi
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
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