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1.
Intern Med ; 2024 Apr 16.
Article in English | MEDLINE | ID: mdl-38631852

ABSTRACT

Objective Frailty is common in patients with heart failure (HF). Given that gardening demands regular physical activity and offers therapeutic relaxation benefits, this activity may reduce frailty. We investigated the association between gardening activities and frailty in patients with HF. Methods, patients, or materials Between August 2022 and March 2023, we surveyed patients at risk of HF and those with HF who regularly attended a cardiology outpatient clinic. Gardening activities were defined as the ongoing cultivation of flowers, vegetables, or fruits for more than a year. The questionnaire assessed the presence or absence of gardening activities as well as the frequency, duration per session, years of experience, and scale of such activities. We calculated the frailty index. Frailty was defined as a frailty index of 0.25 or greater. Results Of the 1,277 respondents, 69% engaged in gardening and 35% were frail. After adjusting for multiple confounding factors, gardening activities showed an inverse association with frailty [odds ratio = 0.723, 95% confidence interval (0.533-0.981)]. Moreover, frailty and the frailty index showed an inverse association with more extended and large-scale gardening activities. Conclusion Gardening activities were thus found to be associated with a low prevalence of frailty in patients with HF.

2.
Biochem Biophys Res Commun ; 687: 149146, 2023 12 20.
Article in English | MEDLINE | ID: mdl-37956599

ABSTRACT

Production of cartilaginous particles for regenerative medicine requires a large supply of chondrocytes and development of suitable production techniques. Previously, we successfully produced human induced pluripotent stem cell (hiPSC)-derived limb bud mesenchymal cells (ExpLBM cells) with a high chondrogenic differentiation potential that stably proliferate. It may be possible to use these cells in combination with a stirred bioreactor to develop a tissue-engineered cell culture technology with potential for scale-up to facilitate production of large amounts of cartilaginous particles. ExpLBM cells derived from 414C2 and Ff-I 14s04 (human leukocyte antigen homozygous) hiPSCs were seeded into a stirred bioreactor containing cartilage induction medium. To characterize the cartilaginous particles produced, we performed real-time quantitative reverse transcription-polymerase chain reaction and histological analyses. Additionally, we transplanted the cartilage tissue into osteochondral defects of immunocompromised rats to assess its functionality, and evaluated engraftment of the grafted tissue. We successfully produced large amounts of cartilaginous particles via cartilage induction culture in a stirred bioreactor. This tissue exhibited significantly increased expression levels of type II collagen (COL2), aggrecan (ACAN), and SRY-box transcription factor 9 (SOX9), as well as positive Safranin O and Toluidine blue staining, indicating that it possesses characteristics of hyaline cartilage. Furthermore, engrafted tissues in osteochondral knee defects of immunodeficient rats were positively stained for human vimentin, COL2, and ACAN as well as with Safranin O. In this study, we successfully generated large amounts of hiPSC-derived cartilaginous particles using a combination of tissue engineering techniques. This method is promising as a cartilage regeneration technology with potential for scale-up.


Subject(s)
Induced Pluripotent Stem Cells , Humans , Rats , Animals , Induced Pluripotent Stem Cells/metabolism , Limb Buds , Chondrocytes/metabolism , Hyaline Cartilage , Cell Differentiation , Tissue Engineering/methods , Aggrecans/metabolism , Bioreactors , Chondrogenesis
3.
Biomed Mater ; 18(6)2023 10 24.
Article in English | MEDLINE | ID: mdl-37827163

ABSTRACT

With the advancement of tissue engineering technologies, implantable materials have been developed for use in facial plastic surgery, including auriculoplasty and rhinoplasty. Tissue-engineered cartilage comprising only cells and cell-produced extracellular matrix is considered valuable as there is no need to consider problems associated with scaffold absorption or immune responses commonly related to conventional artificial materials. However, it is exceedingly difficult to produce large-sized complex shapes of cartilage without the use of scaffolds. In this study, we describe the production of shape-designable cartilage using a novel cell self-aggregation technique (CAT) and chondroprogenitor cells derived from human induced pluripotent stem cells as the source. The method described does not require special equipment such as bio-3D printers, and the produced tissue can be induced into well-matured cartilage with abundant cartilage matrixin vitro. Using CAT, we were able to generate cartilage in the form of rings or tubes with adjustable inner diameter and curvature, over a range of several centimeters, without the use of scaffolds. Thein vitrofabrication of shape-designable cartilage using CAT is a promising development in facial plastic surgery.


Subject(s)
Induced Pluripotent Stem Cells , Tissue Scaffolds , Humans , Cartilage/physiology , Tissue Engineering/methods , Extracellular Matrix , Chondrogenesis
4.
Biomedicines ; 11(4)2023 Apr 07.
Article in English | MEDLINE | ID: mdl-37189741

ABSTRACT

Polyamines are bioactive amines that play a variety of roles, such as promoting cell proliferation and protein synthesis, and the intestinal lumen contains up to several mM polyamines derived from the gut microbiota. In the present study, we conducted genetic and biochemical analyses of the polyamine biosynthetic enzyme N-carbamoylputrescine amidohydrolase (NCPAH) that converts N-carbamoylputrescine to putrescine, a precursor of spermidine in Bacteroides thetaiotaomicron, which is one of the most dominant species in the human gut microbiota. First, ncpah gene deletion and complemented strains were generated, and the intracellular polyamines of these strains cultured in a polyamine-free minimal medium were analyzed using high-performance liquid chromatography. The results showed that spermidine detected in the parental and complemented strains was depleted in the gene deletion strain. Next, purified NCPAH-(His)6 was analyzed for enzymatic activity and found to be capable of converting N-carbamoylputrescine to putrescine, with a Michaelis constant (Km) and turnover number (kcat) of 730 µM and 0.8 s-1, respectively. Furthermore, the NCPAH activity was strongly (>80%) inhibited by agmatine and spermidine, and moderately (≈50%) inhibited by putrescine. This feedback inhibition regulates the reaction catalyzed by NCPAH and may play a role in intracellular polyamine homeostasis in B. thetaiotaomicron.

5.
Stem Cell Res Ther ; 14(1): 34, 2023 02 24.
Article in English | MEDLINE | ID: mdl-36829201

ABSTRACT

BACKGROUND: Cell sheet fabrication for articular cartilage regenerative medicine necessitates a large number of chondrocytes of consistent quality as a cell source. Previously, we have developed human-induced pluripotent stem cell (iPSC)-derived expandable PRRX1+ limb-bud mesenchymal cells (ExpLBM) with stable expansion and high chondrogenic capacity, while in this study; our ExpLBM technology was combined with cell sheet engineering to assess its potential as a stable cell source for articular cartilage regeneration. METHODS: ExpLBM cells derived from human-induced pluripotent stem cells (hiPSCs), including 414C2 and Ff-KVs09 (HLA homozygous), were seeded onto a culture plate and two-dimensional chondrogenic induction (2-DCI) was initiated. After 2-DCI, ExpLBM-derived chondrocytes were stripped and transferred to temperature-responsive culture inserts and the chondrocyte sheets were histologically examined or transplanted into osteochondral knee defects of immunodeficient rats. RESULTS: Immunohistochemistry revealed that ExpLBM-derived cell sheets were positive for Safranin O, COL2, and ACAN but that they were negative for COL1 and RUNX2. Furthermore, the engrafted tissues in osteochondral knee defects in immunodeficient rats were stained with SafO, human VIMENTIN, ACAN, and COL2. CONCLUSIONS: The present study is the first to report the chondrocyte sheet fabrication with hiPSC-derived cell source. hiPSC-derived ExpLBM would be a promising cell source for cell sheet technology in articular cartilage regenerative medicine.


Subject(s)
Cartilage, Articular , Induced Pluripotent Stem Cells , Mesenchymal Stem Cells , Humans , Rats , Animals , Chondrocytes , Knee Joint/pathology , Chondrogenesis , Cell Differentiation , Homeodomain Proteins
6.
PLoS One ; 18(1): e0280673, 2023.
Article in English | MEDLINE | ID: mdl-36662802

ABSTRACT

Culcioides biting midges (Diptera: Ceratopogonidae) are vectors of various veterinary pathogens. Suction light traps are one of the most widely used tools for vector surveillance. The present aim was to compare the efficiency for the collection of Culicoides species between newly developed 3D-printed ultraviolet (Mahidol University (MU) UV LED) and green light-emitting diode (Mahidol University (MU) Green LED) traps baited with CO2 and UV LED Center for Disease Control (CDC) light trap (BioQuip 2770) baited with CO2. The experiment consisted of two replicates of a 3 × 3 Latin square design in each three sampling locations (Location 1, 2, 3 and 4, 5, 6), for 12 nights between 26th July and 7th August 2020 in Thailand. Results showed that efficiency of the MU UV LED light trap was equivalent to that of the BioQuip 2770 trap for the collection of Culicoides. Meanwhile, the efficiency of the MU Green LED light trap was lower than that of both UV LED light traps. In the analysis of Culicoides species composition and sex-age grading, a similar pattern was observed among three light traps except for Culicoides actoni Smith. The newly developed 3D-printed UV LED light trap demonstrated the following advantages over the commercial light trap: cost saving to obtain multiple units, ease of customization and standardization, and increased availability by end-users. Although further assessments in different environmental conditions are needed, this 3D-printed light trap design could minimize the constrains in vector surveillance programs worldwide.


Subject(s)
Ceratopogonidae , Humans , Animals , Thailand , Carbon Dioxide , Specimen Handling , Printing, Three-Dimensional
7.
Stem Cell Res Ther ; 13(1): 515, 2022 Nov 12.
Article in English | MEDLINE | ID: mdl-36371298

ABSTRACT

Tendon regeneration is difficult because detailed knowledge about tendon progenitor cells (TPCs), which produce tenocytes to repair tendon tissue, has not been revealed. Mohawk homeobox (MKX) is a marker of TPCs or tenocytes, but a human pluripotent stem cell (hPSC)-based reporter system that visualizes MKX+ cells has not been developed. Here, we established an hPSC-derived MKX-tdTomato reporter cell line and tested the induction ratio of MKX-tdTomato+ cells using our stepwise/xeno-free differentiation protocol. MKX-tdTomato+ cells were generated with high efficiency and expressed tendon-specific markers, including MKX, SCX, TNMD, and COL1A1. Our MKX-tdTomato hPSC line would be a useful tool for studying the development or regeneration of tendon tissue.


Subject(s)
Pluripotent Stem Cells , Solanum lycopersicum , Humans , Solanum lycopersicum/metabolism , Homeodomain Proteins/genetics , Homeodomain Proteins/metabolism , Cell Differentiation , Tendons/metabolism , Pluripotent Stem Cells/metabolism
8.
J Vet Med Sci ; 84(10): 1442-1446, 2022 Oct 07.
Article in English | MEDLINE | ID: mdl-36047164

ABSTRACT

Two male cats were presented with penile part of urethra injury due to dog attacks to the perineum and genitalia area. Chronic wound around a remained penile part of urethra due to the dog bite and perineal area was evident due to urine irritation. The buccal mucosa was harvested and subsequently placed on the granulation tissue of the wound to reconstruct the urinary passage. The buccal mucosal graft completely attached to the skin and urethra without any complications. From the follow-up at 3 months, the cats were able to urinate normally and the skin irritation from urine was resolved. In summary, the buccal mucosa is a good graft source and is suitable for the reconstruction of the urinary passage in severe and complicated cases of penile part of urethra injury in male cats.


Subject(s)
Bites and Stings , Cat Diseases , Urethral Diseases , Urethral Stricture , Animals , Bites and Stings/veterinary , Cat Diseases/surgery , Cats , Dogs , Male , Mouth Mucosa/surgery , Penis/surgery , Treatment Outcome , Urethra/surgery , Urethral Diseases/veterinary , Urethral Stricture/surgery , Urethral Stricture/veterinary , Urination
9.
Acta Trop ; 224: 106147, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34562422

ABSTRACT

Biting midges of the genus Culicoides Latreille are biological vectors of bluetongue virus (BTV), a member of family Reoviridae, genus Orbivirus. About 30 species of Culicoides have been identified as competent BTV vectors worldwide. Even though high seroprevalence of BTV has been reported among livestock ruminants from western Thailand, the Culicoides species which contribute to BTV transmission remain unclear. In the present study, Culicoides were collected from eight sampling sites, located in two BTV prevalent provinces in western Thailand. Adult Culicoides were identified using wing morphology and cytochrome c oxidase subunit I (COI) mtDNA molecular marker. A total of 9,677 Culicoides specimens belonging to 7 subgenera, 3 species groups, and 23 species were identified. After comparing sequencing results with available data from GenBank, COI sequences of five species were reported for the first time from Thailand. The most abundant potential BTV vector species collected were C. peregrinus, followed by C. orientalis, C. imicola, C. oxystoma, and C. fulvus. Out of 72 Culicoides pools, 9 pools (4 from C. orientalis, 2 from C. imicola, 2 from C. oxystoma, and 1 from C. fulvus) were positive by BTV RT-PCR analyses. These results are new to Culicoides BTV vector knowledge in Thailand and will contribute to further BTV studies in this particular region.


Subject(s)
Bluetongue virus , Bluetongue , Ceratopogonidae , Animals , Bluetongue virus/genetics , Ceratopogonidae/genetics , DNA Barcoding, Taxonomic , Insect Vectors/genetics , Seroepidemiologic Studies , Sheep , Thailand
10.
Biol Pharm Bull ; 44(5): 678-685, 2021.
Article in English | MEDLINE | ID: mdl-33952823

ABSTRACT

To clarify the role of an amino acid residue in the pH-dependent efflux process in Chinese hamster ovary (CHO) cells expressing the human oligopeptide transporter hPEPT1 (CHO/hPEPT1), we determined the effect of extracellular pH on the hPEPT1-mediated efflux process. The efflux of glycylsarcosine (Gly-Sar), a typical substrate for hPEPT1, was determined using an infinite dilution method after cells were preloaded with [3H]-Gly-Sar. The efflux of [3H]-Gly-Sar was stimulated by 5 mM unlabeled hPEPT1 substrates in the medium. This trans-stimulation phenomenon showed that hPEPT1 mediated the efflux of [3H]-Gly-Sar from CHO/hPEPT1 and that hPEPT1 is a bi-directional transporter. We then determined the effect of extracellular pH (varying from 8.0 to 3.5) on the efflux activity. The efflux activity by hPEPT1 decreased with the decrease in extracellular pH. The Henderson-Hasselbälch-type equation, which fitted well to the pH-profile of efflux activity, indicated that a single amino acid residue with a pKa value of approximately 5.7 regulates the efflux activity. The pH-profile of the efflux activity remained almost unchanged irrespective of the proton gradient across the plasma membrane. In addition, the chemical modification of the histidine residue with diethylpyrocarbonate completely abolished the efflux activity from cells, which could be prevented by the presence of 10 mM Gly-Sar. These data indicate that the efflux process of hPEPT1 is also regulated in a pH-dependent manner by the protonation state of a histidine residue located at or near the substrate recognition site facing the extracellular space.


Subject(s)
Histidine/chemistry , Peptide Transporter 1/metabolism , Recombinant Proteins/metabolism , Animals , CHO Cells , Cricetulus , Dipeptides/metabolism , Hydrogen-Ion Concentration , Peptide Transporter 1/chemistry , Peptide Transporter 1/genetics , Protons , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Tritium/chemistry
11.
Biol Pharm Bull ; 41(10): 1523-1529, 2018.
Article in English | MEDLINE | ID: mdl-30270321

ABSTRACT

Hypotaurine is a precursor of taurine and a physiological antioxidant that circulates in adult and fetal plasma. The purpose of the present study was to clarify whether hypotaurine is a substrate of Slc6a/gamma-aminobutyric acid (GABA) transporter family members. Radiolabeled hypotaurine was synthesized from radiolabeled cysteamine and 2-aminoethanethiol dioxygenase. The uptakes of [3H]GABA, [3H]taurine, and [14C]hypotaurine by HEK293 cells expressing mouse GAT1/Slc6a1, TAUT/Slc6a6, GAT3/Slc6a11, BGT1/Slc6a12, and GAT2/Slc6a13 were measured. TAUT and GAT2 showed strong [14C]hypotaurine uptake activity, while BGT1 showed moderate activity, and GAT1 and GAT3 showed slight but significant activity. Mouse TAUT and GAT2 both showed Michaelis constants of 11 µM for hypotaurine uptake. GAT2-expressing cells pretreated with hypotaurine showed resistance to H2O2-induced oxidative stress. These results suggest that under physiological conditions, TAUT and GAT2 would be major contributors to hypotaurine transfer across the plasma membrane, and that uptake of hypotaurine via GAT2 contributes to the cellular resistance to oxidative stress.


Subject(s)
GABA Plasma Membrane Transport Proteins/metabolism , Taurine/analogs & derivatives , gamma-Aminobutyric Acid/metabolism , Adaptation, Physiological , Animals , Biological Transport , HEK293 Cells , Humans , Mice , Oxidative Stress , Taurine/metabolism
13.
Semin Arthritis Rheum ; 47(3): 310-314, 2017 12.
Article in English | MEDLINE | ID: mdl-28532573

ABSTRACT

OBJECTIVE: The aim of the study is to assess the factors associated with clinical remission of patients with rheumatoid arthritis (RA) in daily clinical practice. METHODS: This analysis was based on the data of 304 RA patients in our center between May 2014 and March 2015. The following information was included: tender, swollen, and symptomatic joint counts, patient's and physician's global assessments, functional disability, laboratory and radiographic data, and RA treatments received. RESULTS: The patients were predominantly female (77.6%), with a median age of 71 years and a median disease duration of 5.8 years. Clinical remission rate, determined using the simplified disease activity index (SDAI), was 49.7%. Patient's and physician's global assessments (/10cm) showed a higher score among patients who did not achieve SDAI remission than among those who did (median: 3.2 versus 0.3, p < 0.0001; and median: 1.8 versus 0.3, p < 0.0001, respectively). The contribution of serum C-reactive protein values (mg/dL) to SDAI was limited (median: 0.19 versus 0.06; p < 0.0001), as well as tender or swollen joint counts (median = 0 or 1). On multivariate analysis of factors not directly related to the disease activity, age was an independent risk factor for non-remission, and global assessment scores by patients and physicians showed an age-dependent increase, while counts of tender, swollen and symptomatic joints were comparable among elderly and non-elderly patients. CONCLUSION: Global assessment of disease activity was age-dependent and independent of joint counts, and it provides a critical determinant of clinical non-remission.


Subject(s)
Age Factors , Arthritis, Rheumatoid/physiopathology , Diagnostic Self Evaluation , Disability Evaluation , Joints/physiopathology , Physical Examination/methods , Aged , Antirheumatic Agents/therapeutic use , Arthritis, Rheumatoid/diagnostic imaging , Arthritis, Rheumatoid/drug therapy , C-Reactive Protein/analysis , Case-Control Studies , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Multivariate Analysis , Pain Measurement , Radiography , Remission Induction , Retrospective Studies , Severity of Illness Index
14.
Arthritis Care Res (Hoboken) ; 69(6): 801-806, 2017 06.
Article in English | MEDLINE | ID: mdl-27564121

ABSTRACT

OBJECTIVE: Ultrasonography has been prevalently used as a valid and objective modality for joint examination in patients with rheumatoid arthritis (RA). This study aimed to examine and compare the concordance between ultrasound, clinical assessment, and patient-reported assessment of joint synovitis in RA. METHODS: Fifty patients with RA (84% female, median age 69 years, median disease duration 31 months, and median Disease Activity Score in 28 joints 3.8) completed the self-evaluation of joint symptoms, including pain and considerable stiffness in the (proximal) interphalangeal, metacarpophalangeal, wrist, elbow, shoulder, knee, and ankle joints. These joints were also examined by a physician in order to assess the presence of tenderness or swelling; the presence of imaging synovitis was assessed by ultrasonography. RESULTS: In a total of 1,492 evaluated joints, symptoms (pain and stiffness), tenderness, and swelling were noted in 288 (19.3%), 182 (12.2%), and 220 (14.7%) joints, respectively, while ultrasound indicated synovitis in 317 (21.2%) joints. Overall concordance with ultrasound findings was lowest for joint tenderness (κ = 0.30), followed by symptoms (κ = 0.39), and by swelling (κ = 0.43), irrespective of the evaluated joint, except for the elbow. Moreover, the percentages of inflamed joints detected only on the basis of symptoms, tenderness, or swelling were 18.6%, 2.2%, and 8.5%, respectively, of all joints with signs of synovitis on ultrasonography. CONCLUSION: Joint swelling showed the best concordance with ultrasonography, followed by patient-reported joint symptoms, and joint tenderness. Joint symptoms, rather than tenderness evaluation, may be a better clinical indicator of synovitis in RA patients.


Subject(s)
Arthritis, Rheumatoid/diagnostic imaging , Diagnostic Self Evaluation , Physician's Role , Synovitis/diagnostic imaging , Ultrasonography, Doppler/standards , Adult , Aged , Aged, 80 and over , Arthritis, Rheumatoid/epidemiology , Female , Humans , Male , Middle Aged , Retrospective Studies , Single-Blind Method , Synovitis/epidemiology
16.
Bioorg Med Chem Lett ; 20(6): 1948-52, 2010 Mar 15.
Article in English | MEDLINE | ID: mdl-20172723

ABSTRACT

Water-soluble [60]fullerene (C(60)) derivatives were synthesized to examine their bioactivities. PC12 cells were used as a model of nerve cells and the bioactivities of synthesized C(60) derivatives together with some reported ones were tested. Among the compounds tested, C(60)/(gamma-CyD)(2), C(60)-bis(gamma-CyD) (5) containing C(60)-mono(gamma-CyD) (5'), and C(60)/PVP were sufficiently soluble in water and showed an enhancing effect on the neurite outgrowth of NGF-treated PC12 cells.


Subject(s)
Fullerenes/chemistry , Fullerenes/pharmacology , Nerve Growth Factor/pharmacology , Neurites/drug effects , Animals , PC12 Cells , Rats , Solubility , Water
17.
Biol Pharm Bull ; 29(5): 997-1005, 2006 May.
Article in English | MEDLINE | ID: mdl-16651734

ABSTRACT

Human oligopeptide transporter (hPEPT1) translocates di/tri-peptide by coupling to movement of proton down the electrochemical gradient. This transporter has the characteristics that the pH-profile of neutral dipeptide transport shows a bell-shaped curve with an optimal pH of 5.5. In the present study, we examined the reason for the decrease in the acidic region with hPEPT1-transfected CHO cells stably oeverexpressing hPEPT1 (CHO/hPEPT1). The pH profile of the transport activity vs. pH was measured in the presence of nigericin/monensin. Under this condition, the inwardly directed proton concentration gradient was dissipated while the membrane potential remained. As pH increased the activity increased, and the Henderson-Hasselbalch equation with a single pKa was fitted well to the activity curve. The pKa value was estimated to be 6.7+/-0.2. This value strongly suggests that there is a key amino acid residue, which is involved in pH regulation of transport activity. To identify the key amino acid residue, we examined the effects of various chemical modifications on pH-profile of the transport activity. Modification of carboxyl groups or hydroxyl groups had no significant influence on the pH-profile, whereas a chemical modification of histidine residue with diethylpyrocarbonate (DEPC) completely abolished the transport activity in CHO/hPEPT1 cells. On the other hand, this abolishment was almost prevented by the presence of 10 mM Gly-Sar. This protection was observed only in the presence of the substrate of hPEPT1, indicating that the histidine residue is located at the substrate recognition site. The pH-profile of the transport activity in CHO/hPEPT1 cells treated with DEPC in the presence of 10 mM Gly-Sar also showed a bell-shape similar to that in non-treated CHO/hPEPT1 cells. These data stressed that the histidine residue located at or near the substrate binding site is involved in the pH regulation of transport activity.


Subject(s)
Extracellular Space/metabolism , Symporters/metabolism , Algorithms , Animals , CHO Cells , Caco-2 Cells , Cricetinae , Diethyl Pyrocarbonate/pharmacology , Dipeptides/pharmacology , Extracellular Space/chemistry , Genetic Vectors , Histidine/metabolism , Humans , Hydrogen-Ion Concentration , Indicators and Reagents , Kinetics , Peptide Transporter 1 , Substrate Specificity , Symporters/antagonists & inhibitors , Symporters/biosynthesis
18.
Arch Biochem Biophys ; 445(1): 166-73, 2006 Jan 01.
Article in English | MEDLINE | ID: mdl-16316621

ABSTRACT

In the present study, we measured an electric current induced by substrate transport in a HeLa cell over-expressing a human intestinal di/tri-peptide transporter using the whole-cell patch-clamp technique. Gly-Sar, a typical substrate, induced an inward current associated with its uptake, which showed concentration-dependency following Michaelis-Menten-type kinetics with an apparent K(0.5) of 1.3mM as well as voltage-dependency. An outward current accompanying the efflux of Gly-Sar was also observed after washing out the cell. This outward current was voltage-dependent and was reduced by the inward proton gradient. In the case of hydrophobic dipeptides such as Gly-Phe and Gly-Leu, a distinctive current was observed: after washing out the cells, no outward current was observed, but rather, an 'inward leak' current was sustained in spite of the absence of transportable substrate. This leaky current was abolished by the perfusion of Gly-Sar and subsequent washing. It is considered that the hydrophobic substrate sticks within the substrate-binding site and causes the newly observed state, or the 'inward leak' current.


Subject(s)
Dipeptides/metabolism , Ion Transport , Symporters/physiology , Electrophysiology , HeLa Cells , Humans , Patch-Clamp Techniques , Peptide Transporter 1
20.
In Vivo ; 18(5): 561-9, 2004.
Article in English | MEDLINE | ID: mdl-15523894

ABSTRACT

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is known to induce parkinsonism in humans when it is oxidized to the 1-methyl-4-phenylpyridinium salt (MPP+). We previously reported the syntheses of 1-amino-4-phenyl-1,2,3,6-tetrahydropyridine (APTP) and 1-amino-4-phenyl-pyridinium salt (APP+), the 1-amino analogues of the dopaminergic neurotoxins, MPTP and MPP+, respectively, and demonstrated that both APTP and APP+ are cytotoxic to PC12 cells. In this study, we found that both APTP and APP+ induce apoptotic cell death in PC12 cells. Apoptosis was determined by the Comet assay and flow cytometric analysis. Prior to using the Comet assay for detection of apoptotic PC12 cells, Comet images of apoptotic and necrotic cells were first distinguished by using several standards. Comet images were classified into four groups (A to D) according to their shapes. Class D consisted of the apoptotic cells and was easily distinguished. We also demonstrated that apoptotic and necrotic PC12 cells can be easily differentiated and quantified using the convenient Comet assay.


Subject(s)
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/analogs & derivatives , 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine/pharmacology , 1-Methyl-4-phenylpyridinium/pharmacology , Apoptosis/drug effects , DNA Damage , PC12 Cells/drug effects , 1-Methyl-4-phenylpyridinium/analogs & derivatives , Animals , Comet Assay , DNA Fragmentation , DNA, Neoplasm/analysis , DNA, Neoplasm/drug effects , Flow Cytometry , PC12 Cells/pathology , Pyridinium Compounds , Rats
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