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1.
Benef Microbes ; 12(5): 503-516, 2021 Oct 11.
Article in English | MEDLINE | ID: mdl-34463192

ABSTRACT

There are many studies focusing on the alleviation of menopausal symptoms; however, little is known about the role of gut microorganisms in menopausal symptoms. Ovariectomized (OVX) rats were administered a novel strain (YT2) of Lactobacillus intestinalis (a species with significantly reduced abundance in OVX rats) and the potential probiotic effect on the improvement of menopausal symptoms was evaluated. Of note, the gut microbial composition completely shifted after ovariectomy in rats. Treatment with L. intestinalis YT2 significantly alleviated menopausal symptoms, such as increased fat mass, decreased bone mineral density, increased pain sensitivity, depression-like behaviour, and cognitive impairment. Additionally, the administration of L. intestinalis YT2 restored the intestinal microbial composition, including an increased Firmicutes/Bacteroides ratio. L. intestinalis YT2 also promoted gut barrier integrity by increasing the mRNA levels of tight junction-related markers. In conclusion, L. intestinalis YT2 treatment alleviated menopausal symptoms via the modulation of the gut microbiota. Importantly, these results suggest that L. intestinalis YT2 should be considered as a therapeutic probiotic agent for menopausal women.


Subject(s)
Gastrointestinal Microbiome , Lactobacillus , Menopause , Probiotics/therapeutic use , Animals , Female , Ovariectomy , Rats
2.
Clin Microbiol Infect ; 21(9): 874.e9-874.e21, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26055416

ABSTRACT

Nucleotide sequencing of the phylogenetically informative region of NS5B remains the gold standard for hepatitis C virus (HCV) genotyping. Here we developed a new methodology for sequencing new NS5B regions to increase the accuracy and sensitivity of HCV genotyping and subtyping. The eight new primers were identified by scanning the full-length NS5B regions from 1127 HCV genomic sequences found in HCV databases. The ability of each pair of primers to amplify HCV subtypes was scored, and the new primers were able to amplify the NS5B region better than the previously used primers, therefore more accurately subtyping HCV strains. Sequencing the DNA amplified by the new primer pairs can specifically and correctly detect the five standard HCV subtypes (1a, 2a, 3b, 6a and 1b). We further examined patient samples and found that the new primers were able to identify HCV subtypes in clinical samples with high sensitivity. This method was able to detect all subtypes of HCV in 567 clinical samples. Importantly, three novel HCV subtypes (1b-2a, 1b-2k and 6d-6k) were identified in the samples, which have not been previous reported in China. In conclusion, sequencing the NS5B region amplified by the new NS5B primers is a more reliable method of HCV genotyping and a more sensitive diagnostic tool than sequencing using the previously described primers, and could identify new HCV subtypes. Our research is useful for clinical diagnosis, guidance of clinical treatment, management of clinical patients, and studies on the epidemiology of HCV.


Subject(s)
Genotype , Genotyping Techniques/methods , Hepacivirus/classification , Hepacivirus/genetics , Hepatitis C/virology , Sequence Analysis, DNA/methods , Viral Nonstructural Proteins/genetics , Adult , Aged , China , DNA Primers/genetics , Female , Hepacivirus/isolation & purification , Humans , Male , Middle Aged , Sensitivity and Specificity , Young Adult
3.
Cell Death Dis ; 6: 1655, 2015 Feb 19.
Article in English | MEDLINE | ID: mdl-25695598

ABSTRACT

The Gram-negative bacterium Vibrio vulnificus produces hemolysin (VvhA), which induces cytotoxicity in mammalian cells. However, our understanding of the cytotoxic mechanism and the modes of action of VvhA are still fragmentary and incomplete. The recombinant protein (r) VvhA (50 pg/ml) significantly induces necrotic cell death and apoptosis in human intestinal epithelial (INT-407) cells. The apoptotic cell death induced by rVvhA is highly susceptible to the sequestration of cholesterol by methyl-ß-cyclodextrin, whereas for necrotic cell death, this shows a marginal effect. We found that rVvhA induces the aggregation of lipid raft components coupled with NADPH oxidase enzymes, in which rVvhA increased the interaction of NADPH oxidase 2 (NOX2, gp91(phox)) with a cytosolic protein NCF1 (p47(phox)) to facilitate the production of reactive oxygen species (ROS). rVvhA uniquely stimulated a conventional PKC isoform PKCα and induced the phosphorylation of both ERK and JNK, which are responsible for the activation of transcription factor NF-κB. rVvhA induced an NF-κB-dependent imbalance of the Bcl-2/Bax ratio, the release of mitochondrial cytochrome c, and caspase-3/-9 activation during its promotion of apoptotic cell death. In addition, rVvhA has the ability to inhibit the expression of cell cycle-related proteins, such as CDK2, CDK4, cyclin D1, and cyclin E. These results demonstrate that rVvhA induces NF-κB-dependent mitochondrial cell death via lipid raft-mediated ROS production by the distinct activation of PKCα and ERK/JNK in intestinal epithelial cells.


Subject(s)
Epithelial Cells/cytology , Hemolysin Proteins/metabolism , Intestines/cytology , Membrane Microdomains/metabolism , Mitochondria/metabolism , NF-kappa B/metabolism , Reactive Oxygen Species/metabolism , Vibrio vulnificus/metabolism , Animals , Apoptosis/physiology , Cell Death/physiology , Cytochromes c/metabolism , Rats
4.
Lymphology ; 48(4): 184-96, 2015 Dec.
Article in English | MEDLINE | ID: mdl-27164764

ABSTRACT

The incorporation of resistance exercises into the lifestyle of patients with lymphedema is understudied and an emerging interest. We investigated the effectiveness and results of adding a moderate intensity resistance exercise program for 8 weeks in conjunction with intensive CDT for 1 or 2 weeks (depending on severity) on arm volume, arm function, QOL, and muscular strength in patients with breast cancer-related lymphedema. This prospective, pilot trial included forty-four patients with a history of breast cancer who were beginning complex decongestive therapy for lymphedema. They were assigned to either the intervention (n = 22) or control (n = 22). groups. The intervention comprised of resis- tance band exercises 5 times a week for 8 weeks. These were initially supervised during the intensive lymphedema treatment, but performed independently during the study period. Limb volume, muscular strength, and the European Organization for Research and Treatment of Cancer QOL Questionnaire C30 (EORTC QLQ-C30), EORTC-Breast Cancer-Specific QOL Questionnaire (EORTC QLQ-BR23), and Disabilities of Arm, Shoulder, and Hand (DASH) questionnaires were assessed at baseline and at 8 weeks. After 8 weeks, the intervention group demonstrated statistically significant differences (p < 0.05) in the DASH score and muscular strength compared to the control group. Our results indicate that upper body resistance exercise demonstrates a positive effect on arm function and muscular strength without increasing arm volume in breast cancer related lymphedema during and shortly post intensive CDT lymphedema treatment.


Subject(s)
Breast Neoplasms/surgery , Lymphedema/therapy , Muscle Strength , Physical Therapy Modalities , Resistance Training , Arm/physiopathology , Female , Humans , Mastectomy/adverse effects , Middle Aged , Pilot Projects , Prospective Studies , Quality of Life
5.
Int J Cosmet Sci ; 37(1): 92-7, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25351787

ABSTRACT

OBJECTIVE: The physiological characteristics of the skin are varied greatly, depending on gender, age, region and race, and many dermatologic researches have been performed through various research methods. This study aimed to examine how Korean men's skin conditions were influenced by temperature or humidity changes caused by seasonal rotations. METHODS: A total of 100 healthy Korean men, age range 20-59 years, participated in the study for both summer and winter. We compared on the characteristics of skin between summer and winter. The skin hydration, skin pH and TEWL were evaluated on the forehead, cheek and forearm. The skin sebum content of the glabella, nasal ala and cheek was measured using Sebumeter(®) (SM810, Courage+Khazaka, Germany). Cutometer(®) (MPA 580 Courage+Khazaka, Germany) the elasticity was measured by on the cheeks, and PRIMOS lite(®) (Phase shift Rapid in vivo Measurement of Skin, GFMesstechnik GmbH, Germany) was used to evaluate wrinkles on crow's feet. Lastly, in addition, the skin pore of the face was measured using the Janus(®) (PSI, Korea) which is a facial analysis system. RESULTS: The results were as follows: the comparison of hydration in summer and winter shows significant differences in their forehead, cheeks and forearm. The pH values of the skin surface were generally higher in winter, and significantly different on each site, and the sebum content was higher in summer than in winter. As a result of the pore measurement, the summer showed more pores compared to the winter, and there was a statistically significant difference in skin pores between summer and winter. The sensitivity measured by stinging test increases significantly more in winter than in summer. However, there were no seasonal differences in wrinkles and skin brightness. CONCLUSION: The skin surface pH, TEWL, sebum content, hydration, elasticity, wrinkles, skin pore and skin sensitivity vary with seasons and body regions in Korean men.


Subject(s)
Seasons , Skin Physiological Phenomena , Adult , Humans , Hydrogen-Ion Concentration , Male , Middle Aged , Republic of Korea , Young Adult
6.
Transplant Proc ; 44(1): 109-14, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22310591

ABSTRACT

BACKGROUND: Tacrolimus is a substrate of cytochrome P450 3A (CYP3A) and P-glycoprotein (P-gp), encoded by the CYP3A and ATP-binding cassette subfamily B member 1 (ABCB1) genes, respectively. This study was aimed to investigate the impact of CYP3A and ABCB1 polymorphisms on the tacrolimus pharmacokinetics and clinical outcomes in Korean renal transplant recipients. METHODS: We analyzed data from a cohort of 70 renal transplant recipients receiving tacrolimus. CYP3A4*4, CYP3A4*5, CYP3A4*18, CYP3A5*3, ABCB1 C1236>T, ABCB1 G2677>T/A, and ABCB1 C3435>T polymorphisms were genotyped and correlated to dose-adjusted tacrolimus trough concentration at months 1, 3, 6, and 12 after transplantation. RESULTS: Patients with the CYP3A5*3 alleles showed higher dose-adjusted tacrolimus concentrations for 12 months and higher trough levels until 6 months after transplantation. ABCB1 polymorphisms and haplotypes were not associated with tacrolimus concentrations. In a multivariate analysis, the presence of ≥1 CYP3A5*3 allele was a significant independent variable affecting dose-adjusted tacrolimus concentrations. Glomerular filtration rate, acute rejection, opportunistic infection, and graft survival were not affected by CYP3A5 polymorphisms. Calcineurin inhibitor toxicity, which showed higher tendency in patients with CYP3A5*1 alleles, might be associated with higher tacrolimus dose per kilogram. CONCLUSIONS: The CYP3A5 genotype is a major factor in determining the dose requirement of tacrolimus, and genotyping may be of value in individualization of immunosuppressive therapy of renal transplant patients.


Subject(s)
ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism , Asian People/genetics , Cytochrome P-450 CYP3A/metabolism , Immunosuppressive Agents/pharmacokinetics , Kidney Transplantation , Polymorphism, Single Nucleotide , Tacrolimus/pharmacokinetics , ATP Binding Cassette Transporter, Subfamily B , ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics , Adult , Aged , Chi-Square Distribution , Cytochrome P-450 CYP3A/genetics , Drug Monitoring , Female , Gene Frequency , Glomerular Filtration Rate/drug effects , Graft Rejection/immunology , Graft Rejection/prevention & control , Graft Survival/drug effects , Haplotypes , Humans , Immunosuppressive Agents/administration & dosage , Immunosuppressive Agents/adverse effects , Kaplan-Meier Estimate , Kidney Diseases/chemically induced , Kidney Transplantation/ethnology , Kidney Transplantation/immunology , Linear Models , Linkage Disequilibrium , Logistic Models , Male , Middle Aged , Phenotype , Republic of Korea/epidemiology , Risk Assessment , Risk Factors , Tacrolimus/administration & dosage , Tacrolimus/adverse effects , Treatment Outcome , Young Adult
7.
Tissue Antigens ; 78(5): 401-2, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21707545

ABSTRACT

A new allele HLA-B*48:01:03 showed one nucleotide difference with B*48:01:01 at codon 269 (CCC->CCT).


Subject(s)
HLA-B Antigens/genetics , Alleles , Base Sequence , Codon , Humans , Molecular Sequence Data , Sequence Analysis, DNA
8.
Exp Mol Med ; 33(1 Suppl): 5-18, 2001 Apr 21.
Article in Korean | MEDLINE | ID: mdl-11708325

ABSTRACT

Genomic technologies have enabled rapid accumulation of information from complex biological systems over the last two decades. The complete DNA sequence is now known for many organisms and the informational database obtained from genome sequencing projects has provided the base for the specification of proteome - the protein complement of genome. Genomic functions can be inferred from the analysis of gene structure and gene expression profiles because proteins are the functional molecules of an organism. Integrated technologies including protein separation, identification, characterization and information manage system are essential to analyze the proteins in complex cellular matrix. This study is focusing on the strategies of proteome analysis using sample preparation, 2-dimensional gel electrophoresis, processing of protein spots and identification of proteins, protein-protein interaction and posttranslational modification using MALDI-TOF-MS. 2-D gel electrophoresis is currently the most powerful protein separation technique and MALDI-TOF MS is powerful identification technique for protein and peptides as a sensitive, rapid, and high resolution analytical method. The developed integrated proteome technologies are very useful to understand the biological phenomena at molecular level by identifying the new molecules and their modifications in various cellular processes, and can be applied for biotechnology including medical science.


Subject(s)
Electrophoresis, Gel, Two-Dimensional/methods , Proteome/chemistry , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Databases, Protein , Electrophoresis, Polyacrylamide Gel , Protein Processing, Post-Translational , Sensitivity and Specificity , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/instrumentation
9.
Cell Death Differ ; 8(11): 1093-102, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11687887

ABSTRACT

Rac1 has been implicated in a wide variety of biological processes, including actin remodeling and various signaling cascades. Here we have examined whether Rac1 might be involved in heat shock-induced cell signaling. We found that Rat2 stable cells expressing a dominant negative Rac1 mutant, RacN17 (Rat2-RacN17), were significantly more tolerant to heat shock than control Rat2 cells, and simultaneously inhibited the activation of SAPK/JNK by heat shock compared to control Rat2 cells. However, no discernible effect was observed in typical heat shock responses including total protein synthesis and heat shock protein synthesis. To identify the proteins involved in this difference, we separated the proteins of both Rat2 and Rat2-RacN17 cell lines after heat shock using two-dimensional gel electrophoresis and identified the differentially expressed proteins by matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) after in-gel trypsin digestion. Differentially expressed proteins between two cell lines were identified as vimentin. Rat2-RacN17 cells showed significant changes in vimentin as well as marked changes in vimentin reorganization by heat shock. The vimentin changes were identified as N-terminal head domain cleavage. These results suggest that Rac1 plays a pivotal role in the heat shock-induced signaling cascade by modifying intermediate vimentin filaments.


Subject(s)
Heat-Shock Response/physiology , Vimentin/metabolism , rac1 GTP-Binding Protein/metabolism , Animals , Cell Line/cytology , Cell Line/metabolism , Fibroblasts/cytology , Fibroblasts/metabolism , JNK Mitogen-Activated Protein Kinases , Mitogen-Activated Protein Kinases/metabolism , Mutation/physiology , Rats , Signal Transduction/physiology , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Vimentin/isolation & purification
10.
Am J Hum Genet ; 67(4): 994-9, 2000 Oct.
Article in English | MEDLINE | ID: mdl-10968776

ABSTRACT

Patients with cholestasis-lymphedema syndrome (CLS) suffer severe neonatal cholestasis that usually lessens during early childhood and becomes episodic; they also develop chronic severe lymphedema. The genetic cause of CLS is unknown. We performed a genome screen, using DNA from eight Norwegian patients with CLS and from seven unaffected relatives, all from an extended pedigree. Regions potentially shared identical by descent in patients were further characterized in a larger set of Norwegian patients. The patients manifest extensive allele and haplotype sharing over the 6.6-cM D15S979-D15S652 region: 30 (83.3%) of 36 chromosomes of affected individuals carry a six-marker haplotype not found on any of the 32 nontransmitted parental chromosomes. All Norwegian patients with CLS are likely homozygous for the same disease mutation, inherited from a shared ancestor.


Subject(s)
Cholestasis/genetics , Chromosomes, Human, Pair 15/genetics , Lymphedema/genetics , Alleles , Chromosome Mapping , Consanguinity , Female , Genes, Recessive/genetics , Haplotypes/genetics , Homozygote , Humans , Male , Microsatellite Repeats/genetics , Norway , Pedigree , Syndrome
11.
Biochemistry ; 39(33): 10090-7, 2000 Aug 22.
Article in English | MEDLINE | ID: mdl-10955997

ABSTRACT

Nucleoside diphosphate kinase (NDPK, Nm23) has been implicated as a multifunctional protein. However, the regulatory mechanism of NDPK is poorly understood. We have examined the modification of NDPK in oxidative stresses. We found that oxidative stresses including diamide and H(2)O(2) treatment cause disulfide cross-linking of NDPK inside cells. This cross-linking was reversible in response to mild oxidative stress, and irreversible to strong stress. This suggests that disulfide cross-linked NDPK may be a possible mechanism in the modification of cellular regulation. To confirm this idea, oxidative modification of NDPK has been performed in vitro using purified human NDPK H(2)O(2) inactivated the nucleoside diphosphate (NDP) kinase activity of NDPK by producing intermolecular disulfide bonds. Disulfide cross-linking of NDPK also dissociated the native hexameric structure into a dimeric form. The oxidation sites were identified by the analysis of tryptic peptides of oxidized NDPK, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Intermolecular cross-linking between Cys109-Cys109, which is highly possible based on the X-ray crystal structure of NDPK-A, and oxidations of four methionine residues were identified in H(2)O(2)-treated NDPK. This cross-linkng was confirmed using mutant C109A (NDPK-A(C109A)) which had similar enzymatic activity as a wild NDPK-A. Mutant NDPK-A(C109A) was not cross-linked and was not easily denatured by the oxidant. Therefore, enzymatic activity and the quaternary structure of NDPK appear to be regulated by cross-linking with oxidant. These findings suggest one of the regulatory mechanisms of NDPK in various cellular processes.


Subject(s)
Nucleoside-Diphosphate Kinase/metabolism , Oxidative Stress , Amino Acid Sequence , Animals , Cross-Linking Reagents , Cysteine/chemistry , Cysteine/metabolism , Humans , Mice , Molecular Sequence Data , Nucleoside-Diphosphate Kinase/chemistry , Oxidation-Reduction , Peptide Fragments/chemistry , Protein Processing, Post-Translational , Protein Structure, Quaternary , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Tumor Cells, Cultured
12.
Cancer Biochem Biophys ; 16(4): 347-63, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9925282

ABSTRACT

We have previously established a vincristine resistant human lung cancer cell line (PC-9/VCR) by a stepwise exposure of parental line PC-9 to vincristine. In this study the resistant cells showed enhanced vincristine cytotoxicity in the presence of cytochalasin B and D. The increase in cytotoxicity was associated with an enhanced accumulation and a reduced efflux of vincristine. Colchicine and taxol had no effects on vincristine accumulation. Several cytoplasmic proteins were overexpressed in the resistant cells. The two major ones, with molecular weights of 58.8 kDa and 83.2 kDa, were shown by western blotting to be beta-tubulin and actin, respectively. The polymerized tubulin level in the resistant cells was significantly (p < 0.05) higher than that in the parental cells. These results suggest that the cellular cytoskeletons might play an important role in VCR resistance in the PC-9/VCR human lung cancer cell line.


Subject(s)
Cytochalasin B/pharmacology , Cytochalasin D/pharmacology , Cytoskeleton/drug effects , Drug Resistance, Neoplasm , Tubulin/metabolism , Vincristine/pharmacokinetics , Vincristine/toxicity , Adenocarcinoma , Cell Survival/drug effects , Colchicine/pharmacology , Cyclosporine/pharmacology , Drug Synergism , Humans , Lung Neoplasms , Neoplasm Proteins/metabolism , Paclitaxel/pharmacology , Tubulin/drug effects , Tumor Cells, Cultured , Verapamil/pharmacology
13.
Cell ; 89(4): 655-67, 1997 May 16.
Article in English | MEDLINE | ID: mdl-9160756

ABSTRACT

As a complementary approach to positional cloning, we used in vivo complementation with bacterial artificial chromosome (BAC) clones expressed in transgenic mice to identify the circadian Clock gene. A 140 kb BAC transgene completely rescued both the long period and the loss-of-rhythm phenotypes in Clock mutant mice. Analysis with overlapping BAC transgenes demonstrates that a large transcription unit spanning approximately 100,000 base pairs is the Clock gene and encodes a novel basic-helix-loop-helix-PAS domain protein. Overexpression of the Clock transgene can shorten period length beyond the wild-type range, which provides additional evidence that Clock is an integral component of the circadian pacemaking system. Taken together, these results provide a proof of principle that "cloning by rescue" is an efficient and definitive method in mice.


Subject(s)
Circadian Rhythm/genetics , Trans-Activators/genetics , Animals , Base Sequence , CLOCK Proteins , Chromosome Mapping , Chromosomes, Bacterial , Circadian Rhythm/physiology , Cloning, Molecular , DNA Primers/genetics , Female , Genetic Complementation Test , In Situ Hybridization , Male , Mice , Mice, Transgenic , Mutation , Phenotype , RNA, Messenger/genetics , RNA, Messenger/metabolism , Trans-Activators/physiology
14.
Vis Neurosci ; 12(6): 1177-90, 1995.
Article in English | MEDLINE | ID: mdl-8962835

ABSTRACT

Voltage-gated potassium channels are differentially expressed in the brain, and recent studies have shown that K+ channels show subcellular localization. We characterized the distribution of five different K+ channels in the mouse retina. Each channel was distributed in a unique pattern in the retina and was localized to specific subcellular domains within a given retinal neuron. Kv1.4 and Kv4.2 were consistently found in axonal and somatodendritic portions, respectively, consistent with previous studies in brain. In contrast, Kv1.2, Kv1.3, and Kv2.1 showed variable subcellular distribution depending upon cellular context. These results suggest that no one K+ channel is distributed over the entire length of the neuron to provide a "housekeeping" level of membrane potential stabilization. Instead, we propose that each K+ channel is associated with a specific subcellular functional module, and each local K+ conductance responds uniquely to local voltage and second messenger signals.


Subject(s)
Potassium Channels/metabolism , Retina/metabolism , Animals , Base Sequence , Electric Conductivity , Mice , Mice, Inbred C57BL , Molecular Probes/genetics , Molecular Sequence Data , Neurons/metabolism , Polymerase Chain Reaction , Potassium Channels/physiology , RNA, Messenger/metabolism , Retina/cytology , Tissue Distribution , Transcription, Genetic
15.
J Neurosci ; 15(7 Pt 1): 5004-13, 1995 Jul.
Article in English | MEDLINE | ID: mdl-7623129

ABSTRACT

RT PCR on mRNA from enzymatically dissociated, isolated bipolar cells showed that these neurons express the Shaker-like K+ channels Kv1.1, Kv1.2, and Kv1.3. Immunohistochemical localization showed each channel to have a unique subcellular distribution: Kv1.1 immunoreactivity was detected in the dendrites and axons terminal, whereas Kv1.2 and Kv1.3 subunits were localized to the axon and the postsynaptic membrane of the rod ribbon synapse, respectively. Whole-cell patch-clamp recordings indicated that the activation voltage of the delayed rectifier current of the isolated bipolar cell and the inhibitory constants for current blockade by TEA, 4-AP, and Ba2+ were similar to these same properties measured for Kv1.1 expressed in oocytes. However, the TEA and 4-AP inhibitory constants for the bipolar cell current differed from the inhibitory constants for Kv1.2 or Kv1.3. These results suggest that the current of the isolated rod bipolar cell is most similar to Kv1.1 but that all three channels may function in the intact retina to allow complex modulation of retinal synaptic signals.


Subject(s)
Drosophila/genetics , Drosophila/metabolism , Mutation , Potassium Channels/physiology , Retinal Rod Photoreceptor Cells/metabolism , Animals , Base Sequence , Electric Conductivity , Electrophysiology , Immunohistochemistry , Mice , Mice, Inbred C57BL , Molecular Probes/genetics , Molecular Sequence Data , Polymerase Chain Reaction , Transcription, Genetic
16.
Eur J Pharmacol ; 292(2): 119-25, 1995 Jan 13.
Article in English | MEDLINE | ID: mdl-7720783

ABSTRACT

A human cell subline (PC-9/VCR) resistant to vincristine was established from non-small cell lung cancer PC-9 cells by incremental exposure of the cells to vincristine. The resistant cells showed phenotypic resistance to vincristine (10-fold), colchicine (6.9-fold) and cisplatin (1.4-fold) but they showed sensitivity to other chemotherapeutic agents including melphalan and etoposide VP-16. The characteristics of the vincristine resistance was partially inhibited (5-7-fold) by co-treatment of PC-9/VCR cells with a nontoxic concentration of L-ascorbic acid (25 micrograms/ml). Co-treatment or 96 h pre-treatment with ascorbic acid resulted in potentiation of the vincristine effect on the resistant, but not on the sensitive, cell line. The growth inhibition due to vincristine treatment after 24 or 96 h growth in ascorbic acid-free medium was decreased in the resistant as well as in the sensitive cell line. In both cell lines, enhanced growth rate has been shown after ascorbic acid treatment. Similarly, cross-resistance of PC-9/VCR cells to colchicine could also be blocked by ascorbic acid. In addition, a nontoxic concentration of verapamil, a known multidrug resistance inhibitor, did not affect the resistant phenotype of PC-9/VCR cells. These findings suggest that an ascorbic acid-sensitive mechanism may be involved in drug resistance per se in the human lung cancer cells, which differs from the classical phosphoglycoprotein-mediated or previously reported non-phosphoglycoprotein-mediated multidrug resistance.


Subject(s)
Ascorbic Acid/pharmacology , Carcinoma, Non-Small-Cell Lung/drug therapy , Lung Neoplasms/drug therapy , Vincristine/pharmacology , Carcinoma, Non-Small-Cell Lung/pathology , Cell Division/drug effects , Culture Media , Drug Resistance , Drug Synergism , Humans , Lung Neoplasms/pathology , Tumor Cells, Cultured , Verapamil/pharmacology
17.
Biochem J ; 301 ( Pt 3): 759-64, 1994 Aug 01.
Article in English | MEDLINE | ID: mdl-7914401

ABSTRACT

A human lung-cancer PC-9 subline with acquired resistance to vincristine (VCR), a chemotherapeutic agent, was established with incremental increases of the drug. The resistant PC-9 subline (PC-9/VCR) shows a 12-fold increase in resistance to VCR and a unique cross-resistance pattern: high cross-resistance to the potent VCR analogue colchicine (6.9-fold) and vinblastine (2.5-fold); lower cross-resistance to actinomycin D (1.8-fold), cisplatin (1.2-fold) and adriamycin (1.3-fold) and a sensitivity to melphalan and VP-16 which is similar to that of the parental cell line. A reduced accumulation of VCR in the resistant cells was demonstrated. Interestingly, the VCR resistance of the PC-9/VCR cell line was partially reversed by ascorbic acid, and the drug uptake was enhanced. In contrast, ascorbic acid had no effect on drug tolerance and drug accumulation was not observed in either PC-9 parental cells or known multidrug-resistant (MDR) cells, suggesting that VCR resistance in PC-9/VCR cells results essentially from reduced drug accumulation. It is worth noting that, whereas reduced drug accumulation in the PC-9/VCR cells was susceptible to modulation by ascorbic acid, the increased efflux rate characteristic of the resistant cells was not. Further, there was a higher efflux rate in resistant cells than in parental cells. DNA Southern- and RNA Northern-blot hybridization analyses indicate that PC-9/VCR cells do not contain amplified mdr genes or overexpress P-glycoprotein. In addition, the calcium-channel blocker verapamil, which acts as a competitive inhibitor of drug binding and efflux, did not affect the resistant phenotype of PC-9/VCR cells. These findings suggest an ascorbic acid-sensitive drug uptake mechanism which is important in mediating VCR resistance per se in human lung-cancer cells; this differs from the P-glycoprotein-mediated MDR mechanism.


Subject(s)
Ascorbic Acid/pharmacology , Carcinoma, Non-Small-Cell Lung/metabolism , Drug Resistance , Lung Neoplasms/metabolism , Vincristine/metabolism , Vincristine/therapeutic use , ATP Binding Cassette Transporter, Subfamily B, Member 1 , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/genetics , Carrier Proteins/genetics , Carrier Proteins/physiology , Cisplatin/therapeutic use , Colchicine/therapeutic use , Dactinomycin/therapeutic use , Doxorubicin/therapeutic use , Drug Resistance/genetics , Gene Expression , Humans , Lung Neoplasms/drug therapy , Lung Neoplasms/genetics , Membrane Glycoproteins/genetics , Membrane Glycoproteins/physiology , Tumor Cells, Cultured , Vinblastine/therapeutic use
18.
J Formos Med Assoc ; 92 Suppl 2: S69-75, 1993 Jun.
Article in Chinese | MEDLINE | ID: mdl-7904199

ABSTRACT

A subline (PC-9/VCR) of the human lung adenocarcinoma cell line (PC-9), derived by in vitro exposure to vincristine (VCR), exhibited a 10-12-fold resistance to VCR by MTT and HTCA assay. Compared to the parental cell line (PC-9), PC-9/VCR-resistant cells displayed a reduced accumulation of VCR. The rate of VCR efflux was shown to be enhanced by PC-9/VCR. Unlike multidrug resistance, this efflux was independent of P-glycoprotein overexpression as determined by the Northern blotting method. In addition, PC-9/VCR showed no collateral sensitivity to verapamil. This resistant subline only showed 6.9-fold and 2.5-fold cross resistance to colchicine and vinblastine, respectively. This preliminary result indicates that defective drug accumulation in PC-9/VCR is due to other mechanisms possibly involving the microtubule assembly.


Subject(s)
Adenocarcinoma/pathology , Carrier Proteins/physiology , Lung Neoplasms/pathology , Membrane Glycoproteins/physiology , Vincristine/pharmacokinetics , ATP Binding Cassette Transporter, Subfamily B, Member 1 , Drug Resistance , Humans , Tumor Cells, Cultured/drug effects , Tumor Cells, Cultured/metabolism , Vincristine/pharmacology
19.
Cell Mol Neurobiol ; 11(6): 611-22, 1991 Dec.
Article in English | MEDLINE | ID: mdl-1723658

ABSTRACT

1. The neurons of the retina have electrical properties that are different from those of most of the other neurons of the central nervous system. To identify the voltage-gated ion channels found in the retina, we screened mouse retinal cDNA libraries with oligonucleotide probes homologous to the mammalian K+ channel MBK1 (Kv1.1) and ligated two partial clones to produce a full-length clone with no significant differences from MBK1. 2. Expression of MBK1 mRNA was determined by RNAse protection. MBK1 mRNA was detected in retinal RNA and was also detected in brain, liver, and heart RNAs. 3. We transcribed the full-length clone, injected it into oocytes of Xenopus laevis, and measured the membrane currents 2 to 6 days later. Depolarization from a holding voltage of -90mV induced a slowly activated outward current with a peak value as large as 20 microA. The current inactivated very slowly with a single exponential time course [mean time constant, 6.5 +/- 0.4 sec (SEM) for activation voltage of -10mV]. 4. The outward current was reduced to half-maximal by 0.42 mM tetraethylammonium, 1.1 mM 4-aminopyridine, and 3.2 mM Ba2+ but was not significantly attenuated by Co2+ (1 mM). 5. The reversal potential (measured with tail currents) changed by 53mV per decade change of [K+] from 1 to 77 mM. 6. The voltage for half-maximal activation of the conductance was -26.6mV (+/- 1.7mV), and the voltage required for an e-fold increase in conductance was 6.9mV (+/- 0.5mV). 7. Thus, the mRNA for MBK1 found in the mouse retina causes the expression of a voltage-dependent K+ current which has properties suitable for may retinal neurons.


Subject(s)
Potassium Channels/genetics , Retina/physiology , Animals , Base Sequence , DNA/genetics , Gene Expression , Genomic Library , Membrane Potentials , Mice , Mice, Inbred C57BL , Molecular Sequence Data , Oligonucleotide Probes , Oocytes/physiology , Potassium Channels/metabolism , Potassium Channels/physiology , RNA/analysis , RNA, Messenger/genetics , Retina/metabolism , Xenopus laevis
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