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Lee SC, Snodgrass MJ, Park MK, Sandall OC. Kinetics of removal of carbonyl sulfide by aqueous monoethanolamine. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2001; 35:2352-2357. [PMID: 11414044 DOI: 10.1021/es0017312] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The kinetics of the reaction between carbonyl sulfide and aqueous monoethanolamine (MEA) were studied over a range in temperature (298-348 K) and amine concentrations (5-20 wt%) using a wetted-sphere absorber. The experimental data were interpreted using a zwitterion mechanism. The key physicochemical properties needed to interpret the data are the solubility and diffusivity of COS in the aqueous amine solution. These properties were estimated using the N2O analogy method. Experimental values of N2O solubility were correlated using an extended scaled-particle model, and the measured N2O diffusion coefficients were correlated using a modified Stokes-Einstein equation. Solution densities and viscosities were also measured and correlated in this work. On the basis of the zwitterion mechanism whose rate-limiting step was the deprotonation of a zwitterion, the Arrhenius relationship between the third-order rate constant and the temperature was well correlated with an absolute mean deviation of 0.3%. It could be thus concluded that the overall reaction rate was first-order in the COS concentration and second-order in the MEA concentration.
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Lin JS, Park MK, Nahm MH. Chromogenic assay measuring opsonophagocytic killing capacities of antipneumococcal antisera. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2001; 8:528-33. [PMID: 11329452 PMCID: PMC96095 DOI: 10.1128/cdli.8.3.528-533.2001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Assays measuring opsonophagocytic killing capacity of immune sera are good surrogate assays for assessing pneumococcal vaccine responses, but they are tedious to perform primarily because the enumeration of surviving bacteria requires the counting of individual bacterial colonies. To overcome this limitation, we have developed a simple and rapid chromogenic assay for estimating the number of surviving bacteria. In this method, the conventional opsonophagocytic killing assays were performed in microtiter wells with differentiated HL-60 cells as phagocytes. At the end of the assay the reaction mixture was cultured for an additional 4.5 h to increase the number of bacteria. After the short culture, XTT (3,3'-[1[(phenylamino)carbonyl]-3,4-tetrazolium]-bis[4-methoxy-6-nitro] benzene sulfonic acid hydrate) and coenzyme Q were added to the wells and the optical density at 450 nm was measured. Our study shows that changes in the optical density were proportional to the number of CFU of live bacteria in the wells. Also, the number of bacteria at the end of the 4.5-h culture was found to be proportional to the original number of bacteria in the wells. When the performance of the chromogenic assay was evaluated by measuring the opsonizing titers of Streptococcus pneumoniae serotypes 6B and 19F, the sensitivity and precision of the new method were similar to those of the conventional opsonization assay employing the colony counting method. Furthermore, the results of this chromogenic assay obtained with 33 human sera correlate well with those obtained with the conventional colony counting method (R > 0.90) for the two serotypes (6B and 19F). Thus, this simple chromogenic assay would be useful in rapidly measuring the capacities of antisera to opsonize pneumococci.
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Petersen OH, Tepikin A, Park MK. The endoplasmic reticulum: one continuous or several separate Ca(2+) stores? Trends Neurosci 2001; 24:271-6. [PMID: 11311379 DOI: 10.1016/s0166-2236(00)01787-2] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Ca2+ store and sink in the endoplasmic reticulum (ER) is important for Ca2+ signal integration and for conveyance of information in spatial and temporal domains. Textbooks regard the ER as one continuous network, but biochemical and biophysical studies revealed apparently discrete ER Ca2+ stores. Recent direct studies of ER lumenal Ca2+ movements show that this organelle system is one continuous Ca2+ store, which can function as a Ca2+ tunnel. The concept of a fully connected ER network is entirely compatible with evidence indicating that the distribution of Ca2+ -release channels in the ER membrane is discontinuous with clustering in certain localities.
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Park MK, Ashby MC, Erdemli G, Petersen OH, Tepikin AV. Perinuclear, perigranular and sub-plasmalemmal mitochondria have distinct functions in the regulation of cellular calcium transport. EMBO J 2001; 20:1863-74. [PMID: 11296220 PMCID: PMC125431 DOI: 10.1093/emboj/20.8.1863] [Citation(s) in RCA: 242] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We have identified three distinct groups of mitochondria in normal living pancreatic acinar cells, located (i) in the peripheral basolateral region close to the plasma membrane, (ii) around the nucleus and (iii) in the periphery of the granular region separating the granules from the basolateral area. Three-dimensional reconstruction of confocal slices showed that the perigranular mitochondria form a barrier surrounding the whole of the granular region. Cytosolic Ca(2+) oscillations initiated in the granular area triggered mitochondrial Ca(2+) uptake mainly in the perigranular area. The most intensive uptake occurred in the mitochondria close to the apical plasma membrane. Store-operated Ca(2+) influx through the basolateral membrane caused preferential Ca(2+) uptake into sub-plasmalemmal mitochondria. The perinuclear mitochondria were activated specifically by local uncaging of Ca(2+) in the nucleus. These mitochondria could isolate nuclear and cytosolic Ca(2+) signalling. Photobleaching experiments indicated that different groups of mitochondria were not luminally connected. The three mitochondrial groups are activated independently by specific spatiotemporal patterns of cytosolic Ca(2+) signals and can therefore participate in the local regulation of Ca(2+) homeostasis and energy supply.
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Montaner AD, Park MK, Fischer WH, Craig AG, Chang JP, Somoza GM, Rivier JE, Sherwood NM. Primary structure of a novel gonadotropin-releasing hormone in the brain of a teleost, Pejerrey. Endocrinology 2001; 142:1453-60. [PMID: 11250925 DOI: 10.1210/endo.142.4.8077] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The neuropeptide GnRH is the major regulator of reproduction in vertebrates acting as a first signal from the hypothalamus to pituitary gonadotropes. Three GnRH molecular variants were detected in the brain of a fish, pejerrey (Odontesthes bonariensis), using chromatographic and immunological methods. The present study shows that one form is identical to chicken GnRH-II (sequence analysis and mass spectrometry) and the second one is immunologically and chromatographically similar to salmon GnRH. The third form was proven to be a novel form of GnRH by isolating the peptide from the brain and determining its primary structure by chemical sequencing and mass spectrometry. The sequence of the novel pejerrey GnRH is pGlu-His-Trp-Ser-Phe-Gly-Leu-Ser-Pro-Gly-NH(2), which is different from the known forms of the vertebrate and protochordate GnRH family. The new form of GnRH is biologically active in releasing gonadotropin and GH from pituitary cells in an in vitro assay.
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81
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Bayliss EA, Park MK, Westfall JM, Zamorkski MA. Clinical inquiries. How can I improve patient adherence to prescribed medication? THE JOURNAL OF FAMILY PRACTICE 2001; 50:303-304. [PMID: 11300979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Park MK, Menard SW, Schoolfield J. Prevalence of overweight in a triethnic pediatric population of San Antonio, Texas. Int J Obes (Lond) 2001; 25:409-16. [PMID: 11319640 DOI: 10.1038/sj.ijo.0801550] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/1999] [Revised: 09/04/2000] [Accepted: 10/04/2000] [Indexed: 11/09/2022]
Abstract
OBJECTIVES To investigate the prevalence of overweight among different ethnic and gender groups of children and adolescents in the San Antonio, Texas, area and to compare the prevalence with that of the US national figures. DESIGN Cross-sectional study SUBJECTS A total of 7208 schoolchildren in kindergarten through 12th grade. There were 4215 Mexican American (MA) (58.5%), 2040 non-Hispanic white (NHW) (28.3%) and 953 African American (AA) (13.2%) subjects. MEASUREMENTS Weight, height and skinfold thicknesses. RESULTS The body mass index (BMI, kg/m2) values of MA boys were almost consistently and significantly (P<0.05) larger than NHW boys and showed a tendency to be larger than AA boys, beginning as early as age 6 and continuing through age 17. Although rarely significant, a similar trend in ethnic difference was also noted for girls, with the smallest BMI seen in NHW girls. The subscapular skinfold thickness (SST) for MA boys and girls was significantly (P<0.05) larger than that for NHW counterparts and showed a tendency to be larger than AA counterparts. No significant ethnic differences were present in the triceps skinfold thickness (TST) for girls, but MA boys' TST were occasionally larger (P<0.05) than other ethnic-gender groups. Girls' TST were frequently larger (P<0.05) than boys for each ethnic groups. Using the population data from the National Health and Nutrition Examination Survey (NHANES) I as reference, the prevalence of overweight (BMI> or =95th percentile) was greater in MA (15-28%) and AA (11-29%) boys and girls than in NHW (7-17%) counterparts. The combined prevalence of overweight and 'at risk of overweight' (BMI>85th percentile) was much larger in MA boys (40-50%), MA girls (34-52%), and AA girls (33-51%) than other subgroups. The onset of overweight is quite early, starting at 5-6 y of age, especially in girls. Compared to the data from national surveys, the prevalence of overweight found in this study is higher than reported nationally. We found a marked increase in the skinfold thickness, especially SST for boys, but the increase is less for girls. CONCLUSIONS The prevalence of overweight is higher in MA boys and girls and AA girls than other ethnic-gender groups in the San Antonio, Texas, area. The prevalence of childhood overweight in the San Antonio area is higher than national figures. The findings of increasing prevalence and early onset of childhood overweight are concerning, because these are known risk factors for diabetes and diseases of many other organ systems. Measures to prevent, reduce or treat childhood obesity are urgently needed.
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Park MK, Menard SW, Yuan C. Comparison of auscultatory and oscillometric blood pressures. ARCHIVES OF PEDIATRICS & ADOLESCENT MEDICINE 2001; 155:50-3. [PMID: 11177062 DOI: 10.1001/archpedi.155.1.50] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To study the differences in blood pressure readings between the auscultatory and oscillometric (Dinamap model 8100; Critikon, Tampa, Fla) methods. DESIGN Survey of 2 blood pressure instruments. SETTING Public schools. PARTICIPANTS Seven thousand two hundred eight schoolchildren aged 5 through 17 years. MAIN OUTCOME MEASURE Blood pressure levels. RESULTS For all children combined, Dinamap systolic pressure readings were 10 mm Hg higher (95% confidence interval, -4 to 24 mm Hg) than the auscultatory systolic pressure readings. Dinamap diastolic pressure readings were 5 mm Hg higher (95% confidence interval, -14 to 23 mm Hg) than the auscultatory Korotkoff phase V diastolic pressure readings. CONCLUSION These findings preclude the interchange of readings by the 2 methods. Caution must be exercised in the diagnosis of hypertension when an automated device is used.
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Briles DE, Hollingshead SK, King J, Swift A, Braun PA, Park MK, Ferguson LM, Nahm MH, Nabors GS. Immunization of humans with recombinant pneumococcal surface protein A (rPspA) elicits antibodies that passively protect mice from fatal infection with Streptococcus pneumoniae bearing heterologous PspA. J Infect Dis 2000; 182:1694-701. [PMID: 11069242 DOI: 10.1086/317602] [Citation(s) in RCA: 196] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2000] [Revised: 08/01/2000] [Indexed: 11/04/2022] Open
Abstract
Pneumococcal surface protein A (PspA), a cross-reactive protein expressed by all pneumococci, is known to elicit an antibody in animals that can passively protect mice from infection with Streptococcus pneumoniae. A phase I trial with recombinant PspA showed the protein to be immunogenic in humans. Pre- and postimmune serum samples from this trial were examined, and human antibody to PspA could protect mice from pneumococcal infection. The serum samples of subjects immunized twice with 125 microg of PspA had >100 times as much antibody per milliliter as was required to consistently protect mice from fatal infection (1.3 microg/dose). At least 98% of PspAs fall into PspA sequence/serologic families 1 or 2. Human antibodies elicited by a family 1 PspA protected against infection with S. pneumoniae expressing either family 1 or 2 PspAs and with strains of all 3 capsular types tested: 3, 6A, and 6B. These studies suggest that PspA may have efficacy as a human vaccine.
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Kim WY, Kim JM, Han SB, Lee SK, Kim ND, Park MK, Kim CK, Park JH. Steaming of ginseng at high temperature enhances biological activity. JOURNAL OF NATURAL PRODUCTS 2000; 63:1702-1704. [PMID: 11141123 DOI: 10.1021/np990152b] [Citation(s) in RCA: 300] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The present study was performed to evaluate the effect of steaming ginseng at a temperature over 100 degrees C on its chemical constituents and biological activities. Raw ginseng was steamed at 100, 110, and 120 degrees C for 2 h using an autoclave. The ginseng steamed at 120 degrees C was more potent in its ability to induce endothelium-dependent relaxation. Steaming the raw ginseng at 120 degrees C also remarkably increased the radical-scavenging activity. Ginsenosides F(4), Rg(3), and Rg(5), which were not present in raw ginseng, were produced after steaming. Ginsenosides Rg(3) and Rg(5) were the most abundant ginsenosides in the ginseng steamed at 120 degrees C, accounting for 39% and 19% of all ginsenosides, respectively.
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86
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Park MK, Petersen OH, Tepikin AV. The endoplasmic reticulum as one continuous Ca(2+) pool: visualization of rapid Ca(2+) movements and equilibration. EMBO J 2000; 19:5729-39. [PMID: 11060024 PMCID: PMC305795 DOI: 10.1093/emboj/19.21.5729] [Citation(s) in RCA: 187] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigated whether the endoplasmic reticulum (ER) is a functionally connected Ca(2+) store or is composed of separate subunits by monitoring movements of Ca(2+) and small fluorescent probes in the ER lumen of pancreatic acinar cells, using confocal microscopy, local bleaching and uncaging. We observed rapid movements and equilibration of Ca(2+) and the probes. The bulk of the ER at the base was not connected to the granules in the apical part, but diffusion into small apical ER extensions occurred. The connectivity of the ER Ca(2+) store was robust, since even supramaximal acetylcholine (ACh) stimulation for 30 min did not result in functional fragmentation. ACh could elicit a uniform decrease in the ER Ca(2+) concentration throughout the cell, but repetitive cytosolic Ca(2+) spikes, induced by a low ACh concentration, hardly reduced the ER Ca(2+) level. We conclude that the ER is a functionally continuous unit, which enables efficient Ca(2+) liberation. Ca(2+) released from the apical ER terminals is quickly replenished from the bulk of the rough ER at the base.
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Schwartz GN, Kammula U, Warren MK, Park MK, Yan XY, Marincola FM, Gress RE. Thrombopoietin and chemokine mRNA expression in patient post-chemotherapy and in vitro cytokine-treated marrow stromal cell layers. Stem Cells 2000; 18:331-42. [PMID: 11007917 DOI: 10.1634/stemcells.18-5-331] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
CD34(+) cells and megakaryocyte progenitors were lower in marrow from patients after hematological recovery from the first cycle of 5-fluorouracil, leucovorin, adriamycin, cyclophosphamide (FLAC) chemotherapy plus PIXY321 (GM-CSF/interleukin 3; IL-3 hybrid) than in FLAC + GM-CSF or pre-FLAC marrows. Marrow stromal layers, an in vitro model of the marrow microenvironment, express a combination of stimulatory and inhibitory factors that modulate hematopoietic progenitor cell proliferation and differentiation. The TaqMan assay and quantitative reverse transcriptase-polymerase chain reaction were used to measure monocyte chemoattractant protein-1 (MCP-1), melanoma stimulatory growth activity, and monokine inducible by interferon-gamma (Mig) (inhibitory chemokines for primitive or megakaryocyte progenitors) mRNA levels in in vitro PIXY and GM-CSF-treated and patient post-FLAC marrow stromal layers. Chemokine mRNA was increased after in vitro GM-CSF and to a lesser extent after PIXY treatment. MCP-1 mRNA levels were fivefold higher in FLAC + PIXY than in FLAC + GM-CSF layers, and Mig mRNA was elevated in FLAC + GM-CSF layers. Thrombopoietin (TPO), insulin-like growth factor I (IGF-I), and IGF-II (stimulatory factors for primitive and megakaryocyte progenitors) mRNA were also measured. TPO mRNA levels were 30% lower in GM-CSF and PIXY-pretreated than in control layers with no decrease in IGF mRNA. TPO mRNA in stromal layers of patients who developed grade 3 thrombocytopenia (platelets < 20 x 10(9)/l) during the third cycle of FLAC was only 24% of levels in stromal layers of marrow from other post-FLAC patients. Results demonstrate that patient and in vitro treatment had modulatory effects on TPO and chemokine mRNA expression in marrow stromal layers.
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Mochizuki Y, Park MK, Mori T, Ogura A, Kawashima S. Formation of lipofuscin-like autofluorescent materials in NG108-15 cells: involvement of lysosomal protein degradation. Gerontology 2000; 44:1-8. [PMID: 9436008 DOI: 10.1159/000021975] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We found that neuroblastoma x glioma hybrid NG108-15 cells accumulated lipofuscin-like autofluorescent materials during neuronal differentiation in culture in a medium containing 1% fetal calf serum, 1 mM dibutyryl cyclic AMP and 1 mM theophylline. The emission maximum of the lipofuscin-like autofluorescent materials was between 500 and 550 nm. Granules positive to acid phosphatase and periodic-acid Schiff were increased, as were the autofluorescent granules in NG108-15 cells. Thiolprotease inhibitors, N-(L-3-trans-carboxyoxirane-2-carbonyl)-L-leucine-4-aminobutyla mide (E-64) and acetyl-Leu-Leu-Arg (leupeptin), markedly accelerated the accumulation of the lipofuscin-like autofluorescent materials in NG108-15 cells. On the other hand, activities of lysosomal thiolproteases, cathepsin B, C and L, were increased during neuronal differentiation. Protein content in the cells was gradually increased with the neuronal differentiation, and the rise was significantly accelerated when proteolysis was inhibited by E-64. These results suggest that the lipofuscin-like autofluorescent materials contain peptidic substances as a component, and indicate that the increase in hydrolytic activities of thiolproteases during neuronal differentiation is not enough for the hydrolysis of peptidic substrates, resulting in the accumulation of autofluorescent materials in NG108-15 cells.
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89
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Harris SL, Park MK, Nahm MH, Diamond B. Peptide mimic of phosphorylcholine, a dominant epitope found on Streptococcus pneumoniae. Infect Immun 2000; 68:5778-84. [PMID: 10992485 PMCID: PMC101537 DOI: 10.1128/iai.68.10.5778-5784.2000] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Even in the age of antibiotics, Streptococcus pneumoniae causes significant morbidity, especially in the young, the elderly, and the immunocompromised. While a carbohydrate-based vaccine exists, it is poorly immunogenic in the at-risk populations. In mice, antibodies directed against phosphorylcholine (PC), an epitope present on the cell wall C polysaccharide of all pneumococcal serotypes, protect against infection. However, PC itself is a poor vaccine candidate. We report here peptide mimics of PC based on the anti-idiotypic interaction of T15 anti-PC antibodies. T15 antibodies, the dominant and protective idiotype induced in mice by PC immunization, self-associate via a 24-amino-acid region in the PC binding site (ASRNKANDYTTEYSASVKGRFIVS; peptide 1). Peptide 1 has been shown to bind in the PC binding site. We demonstrated that amino acid sequences derived from peptide 1 starting at amino acid 9, 11, or 13 inhibit PC binding. Therefore, we immunized mice with bovine serum albumin (BSA) conjugates of peptide 1 or either of two selected 12-mers. The 12-mer peptides were not immunogenic. Mice immunized with peptide 1-BSA developed an anti-PC response consisting mainly immunoglobulin G1 and expressed the T15 heavy chain. Nonetheless, neither BALB/c nor CBA/N mice were protected from lethal pneumococcal infections by immunization with peptide 1-BSA. Preliminary data suggest that peptide 1-BSA is not able to elicit the canonical T15 light chain, explaining the absence of protection. This idiotype-derived mimotope of PC is a useful tool for understanding immunologic cross-reactivity and learning to design T-cell-dependent vaccines for S. pneumoniae.
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90
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Kim CH, Rhee PL, Rhee JC, Kim YI, So I, Kim KW, Park MK, Uhm DY, Kang TM. Hypotonic swelling increases L-type calcium current in smooth muscle cells of the human stomach. Exp Physiol 2000; 85:497-504. [PMID: 11038400 DOI: 10.1017/s0958067000020133] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The purpose of the present study was to characterize the Ca2+ channels in smooth muscle cells from human stomach and to examine the effects of osmotic swelling on the channel activity. Ca2+ channel current with either Ca2+ or Ba2+ as charge carrier was recorded from freshly isolated smooth muscle cells using the conventional whole-cell patch clamp technique. The degree of cell swelling as a result of hypotonic challenge was monitored using a video image analysis system. The changes in intracellular Ca2+ concentration ([Ca2+]i) were measured by microfluorimetry. The pharmacological and voltage activation profile suggests a typical dihydropyridine-sensitive L-type Ca2+ current. Cell swelling, induced by hypotonic challenge, enhanced the amplitude of currents through L-type Ca2+ channels without significant effects on steady-state voltage dependency. After treatment with the L-type Ca2+ channel agonist Bay K 8644 (0.1-2 microM), no further significant increase in calcium channel current or corresponding [Ca2+]i transients were provoked by the swelling. The above results demonstrated that the presence of L-type Ca2+ current in smooth muscle cells of the human stomach and the augmentation of the current are closely associated with the volume increase resulting from hypotonic swelling.
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MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Barium/metabolism
- Calcium/metabolism
- Calcium Channel Agonists/pharmacology
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/metabolism
- Cell Size
- Cells, Cultured
- Dihydropyridines/pharmacology
- Electric Conductivity
- Fluorometry
- Gastric Mucosa/metabolism
- Humans
- Hypotonic Solutions
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Osmotic Pressure
- Patch-Clamp Techniques
- Stomach/cytology
- Stomach/drug effects
- Stomach/physiology
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Park MK, Briles DE, Nahm MH. A latex bead-based flow cytometric immunoassay capable of simultaneous typing of multiple pneumococcal serotypes (Multibead assay). CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2000; 7:486-9. [PMID: 10799465 PMCID: PMC95898 DOI: 10.1128/cdli.7.3.486-489.2000] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A simple and rapid method of simultaneously determining 15 Streptococcus pneumoniae serotypes was developed. Fifteen latex beads of different sizes and different red fluorescence levels were coated with 1 of 15 serotypes (1, 3, 4, 5, 6A, 6B, 7F, 9N, 9V, 14, 18C, 19A, 19F, 22F, and 23F) of pneumococcal capsular polysaccharide (PS). The bead mixture was incubated with individual pneumococcal lysate, a pool of rabbit antisera capable of binding the 15 serotypes, and fluorescein (green fluorescence)-conjugated anti-rabbit antibody. Bead size, red fluorescence, and green fluorescence were measured in a single flow cytometer run. The green fluorescence of the beads was inhibited only when there was a serotypic match between PS on the bead and PS in the pneumococcal lysate. This method distinguished cross-reactive serotypes and correctly identified the serotypes in 100% of 86 pneumococcal isolates tested.
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92
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Rhee JC, Rhee PL, Park MK, So I, Uhm DY, Kim KW, Kang TM. Muscarinic receptors controlling the carbachol-activated nonselective cationic current in guinea pig gastric smooth muscle cells. JAPANESE JOURNAL OF PHARMACOLOGY 2000; 82:331-7. [PMID: 10875753 DOI: 10.1254/jjp.82.331] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Muscarinic receptor subtypes controlling the nonselective cationic current in response to carbachol (ICCh) were studied in circular smooth muscle cells of the guinea pig gastric antrum using putative muscarinic agonists and antagonists. Both oxotremorine-M (an M2-selective agonist) and CCh dose-dependently activated the cationic current with EC50 values of 0.21 +/- 0.01 microm and 0.97 +/- 0.06 microM, respectively. In contrast, pilocarpine and McN-A 343 (an M1-selective and a putative M4 agonist) were weak partial agonists. In response to 10/microM CCh, 4-DAMP, methoctramine and pirenzepine dose-dependently inhibited ICCh and had IC50 values of 1.91 +/- 0.2 nM, 0.46 +/- 0.07 microM and 8.33 +/- 0.4 microM, respectively. 4-DAMP, methoctramine and pirenzepine shifted the concentration-response curves of ICCh to the right without significantly reducing the maximal current. Values of the apparent dissociation constant pA2 obtained from Schild plot analysis were 9.24, 7.72 and 6.62 for 4-DAMP, methoctramine and pirenzepine, respectively. Also, pertussis toxin completely blocked ICCh generation. These results suggest that the M2-subtype plays a crucial role in the activation of the ICCh, and a block of the M3-subtype reduces the sensitivity of the M2-mediated response with no significant reduction of maximum response.
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93
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Park MK, Tepikin AV, Petersen OH. The relationship between acetylcholine-evoked Ca(2+)-dependent current and the Ca2+ concentrations in the cytosol and the lumen of the endoplasmic reticulum in pancreatic acinar cells. Pflugers Arch 1999; 438:760-5. [PMID: 10591062 DOI: 10.1007/s004249900128] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
In a study of isolated mouse pancreatic acinar cells, we used the patch-clamp whole-cell recording configuration to monitor the Ca(2+)-dependent inward ionic current and simultaneously measured the Ca2+ concentration in either the cytosol ([Ca2+]i) or the lumen of the endoplasmic reticulum ([Ca2+]Lu), using appropriate Ca(2+)-sensitive fluorescent probes. A high concentration of acetylcholine (ACh, 10 microM) evoked an increase in [Ca2+]i, which resulted in the activation of Ca(2+)-dependent inward current. Continued ACh application for several minutes led to a marked reduction in both the current and the [Ca2+]i response and after about 4-10 min of sustained ACh stimulation, the inward current response had disappeared and [Ca2+]i was back to the pre-stimulation level. Repeated stimulation with shorter pulses of ACh (10 microM) resulted in responses of declining magnitude both in terms of inward current and [Ca2+]i rises. The ACh-activated inward current was entirely dependent on the elevation of [Ca2+]i, but at a relatively high [Ca2+]i the current was saturated. ACh caused a rapid release of Ca2+ from the lumen of the endoplasmic reticulum and after discontinuation of stimulation, [Ca2+]Lu was only very slowly (10-15 min) fully restored to the pre-stimulation level. Repeated applications of ACh did not change the relationships between the Ca(2+)-dependent current and [Ca2+]i or the current and [Ca2+]Lu. When [Ca2+]Lu was greater than 100 microM, the ACh-evoked Ca2+ release from the store was so large that the current response was initially saturated. We conclude that the ACh-evoked current response essentially depends on the release of stored Ca2+. Desensitization is mainly due to the relatively slow reloading of the intracellular stores with Ca2+.
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Shin YG, Cho KH, Kim JM, Park MK, Park JH. Determination of betaine in Lycium chinense fruits by liquid chromatography-electrospray ionization mass spectrometry. J Chromatogr A 1999; 857:331-5. [PMID: 10536853 DOI: 10.1016/s0021-9673(99)00720-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A rapid and sensitive high-performance liquid chromatography-electrospray mass spectrometric method has been developed for the determination of betaine in Lycium chinense fruits. Betaine was analyzed on a system consisting of a NH2 stationary phase and a mobile phase of water-acetonitrile (25:75) by isocratic elution for 40 min. Betaine was identified and quantitated by electrospray ionization mass spectrometry with selected ion monitoring of the protonated ion [Betaine+H]+ and clustered ions [nBetaines+H]+. The limit of detection for betaine by this method was ca. 0.2 ng/ml and the relative standard deviations of the assay (intra- and inter-day) were less than 8.1%.
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Abstract
INTRODUCTION The purpose of this study were to: (a) examine for possible ethnicity-related and gender-related differences in blood pressure (BP) in Mexican American and non-Hispanic White schoolchildren; (b) compare auscultatory and oscillometric BP levels; and (c) establish auscultatory BP standards using the width of the BP cuff based on the circumference of the arm in schoolchildren in K-12. METHODS Participants were 6259 schoolchildren in kindergarten through 12th grade in the San Antonio, Texas, area. Auscultatory and oscillometric BP readings were obtained in random sequence, using BP cuff width 40% to 50% of the circumference of the upper arm. Averages of 3 readings were used for statistical analyses. RESULTS Auscultatory systolic pressures (SPs) in preadolescent Mexican American boys and girls were higher (1 to 3 mm Hg) auscultatory (SP) than in their White counterparts, but the difference was clinically not important. Diastolic pressures (DP) showed no important differences. Auscultatory SPs in 13- to 18-year-old boys of both ethnic groups were significantly (P < .05) higher (3 to 12 mm Hg) than they were for girls, with no ethnic differences. Oscillometric SP was higher than auscultatory SP in children of all ages studied. Oscillometric (DP) was slightly lower (0 to 5 mm Hg) than was auscultatory K4 and higher (4 to 5 mm Hg) than was auscultatory K5 DP. DISCUSSION No important ethnicity-related difference was found for auscultatory BP, but significant gender-related differences (boys greater than girls) were found in SP in subjects ages 13 to 18 years. Differences in BP readings by oscillometric and auscultatory methods do not allow interchange of readings. This study provides, for the first time, auscultatory BP standards using BP cuff width 40% to 50% of the arm circumference.
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Shin EY, Lee JY, Park MK, Chin YH, Jeong GB, Kim SY, Kim SR, Kim EG. Overexpressed alpha3beta1 and constitutively activated extracellular signal-regulated kinase modulate the angiogenic properties of ECV304 cells. Mol Cells 1999; 9:138-45. [PMID: 10340467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
ECV304, a spontaneously transformed cell line derived from the human umbilical vein endothelial cell (HUVEC) (Takahashi et al., 1990), has been developed as an in vitro angiogenesis model. In the present study, we further characterized the angiogenic properties of this cell line. Compared to HUVEC, ECV304 cells showed distinct features including a higher activity of cellular adhesion, slower but reproducible progression of angiogenesis on Matrigel, and resistance to apoptosis. Thus, the expression of integrin and activation of extracellular-signal regulated kinase 1/2 (Erk1/2), a downstream effector of the integrin pathway, were examined. Flow cytometry revealed that alpha3beta1 integrin was markedly upregulated in ECV304 cells, while alpha(v)beta1 and alpha5beta1 integrins were slightly downregulated. Consistent with this, the binding activity to collagen type IV and laminin, major extracellular matrices of Matrigel, was increased 1.4- and 1.9-fold in ECV304 cells, respectively. This tight binding may retard the initial stage of sprouting and migration in the angiogenesis of ECV304 cells. It has been further demonstrated that Erk1/2 is constitutively active in ECV304 cells, rendering them resistent to the inhibitory effect of PD98059 on proliferation. However, migration of both HUVEC and ECV304 cells was inhibited to a similar extent by PD98059 in a dose-dependent manner. Up to 50 microM of PD98059, no significant changes in cell binding and tubulogenesis on Matrigel was observed in ECV304 cells. In contrast, the tubulogenesis of HUVEC was severely impaired by PD98059. Elevated Erk1/2 activity in ECV304 cells was suppressed by dominant negative H-Ras, but not by cytochalasin D. These results suggest that the overexpression of alpha3beta1 integrin and the constitutive activation of Erk1/2 play a key role in the alteration of the angiogenic properties of ECV304 cells.
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Shin EY, Lee JY, Park MK, Jeong GB, Kim EG, Kim SY. H-Ras is a negative regulator of alpha3beta1 integrin expression in ECV304 endothelial cells. Biochem Biophys Res Commun 1999; 257:95-9. [PMID: 10092516 DOI: 10.1006/bbrc.1999.0302] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have examined the role of Ras in integrin expression in ECV304 endothelial cells. Among the integrins examined in stable ECV304 transfectants expressing dominant active H-Ras (DAR-ECV), expression of alpha3beta1 integrin showed a prominent reduction in all the DAR-ECV clones when compared to the parental ECV304 cells. This implies that H-Ras negatively regulates the expression of alpha3beta1 integrin in ECV304 cells. When treated with inhibitors of the Ras downstream pathway (LY294002, PD98059, SB203580), the expression of alpha3beta1 integrin was up-regulated most significantly by LY294002, suggesting that among the downstream pathways of Ras, phosphatidylinositol 3-kinase is a major determinant. With the application of blocking antibody to alpha3beta1 integrin (2 - 2 x 10(4) nM), migration of ECV304 cells was enhanced to maximal (18%) at 20 nM. These results suggest that migration of endothelial cells could be modulated by H-Ras via alteration of the expression levels of alpha3beta1 integrin.
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Rabin RL, Park MK, Liao F, Swofford R, Stephany D, Farber JM. Chemokine receptor responses on T cells are achieved through regulation of both receptor expression and signaling. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1999; 162:3840-50. [PMID: 10201901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
To address the issues of redundancy and specificity of chemokines and their receptors in lymphocyte biology, we investigated the expression of CC chemokine receptors CCR1, CCR2, CCR3, CCR5, CXCR3, and CXCR4 and responses to their ligands on memory and naive, CD4 and CD8 human T cells, both freshly isolated and after short term activation in vitro. Activation through CD3 for 3 days had the most dramatic effects on the expression of CXCR3, which was up-regulated and functional on all T cell populations including naive CD4 cells. In contrast, the effects of short term activation on expression of other chemokine receptors was modest, and expression of CCR2, CCR3, and CCR5 on CD4 cells was restricted to memory subsets. In general, patterns of chemotaxis in the resting cells and calcium responses in the activated cells corresponded to the patterns of receptor expression among T cell subsets. In contrast, the pattern of calcium signaling among subsets of freshly isolated cells did not show a simple correlation with receptor expression, so the propensity to produce a global rise in the intracellular calcium concentration differed among the various receptors within a given T cell subset and for an individual receptor depending on the cell where it was expressed. Our data suggest that individual chemokine receptors and their ligands function on T cells at different stages of T cell activation/differentiation, with CXCR3 of particular importance on newly activated cells, and demonstrate T cell subset-specific and activation state-specific responses to chemokines that are achieved by regulating receptor signaling as well as receptor expression.
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Yim ES, Park MK, Han BH. Effects of ultrasound on the formation of alpha-benzoylbenzyl cyanide from benzyl cyanide and alkylphenyl ketone from alpha-alkylbenzyl cyanide by potassium superoxide in the presence of crown ether. ULTRASONICS SONOCHEMISTRY 1999; 6:105-109. [PMID: 11233929 DOI: 10.1016/s1350-4177(98)00036-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Ultrasound accelerates the formation of alpha-benzoylbenzyl cyanide and benzoic acid in the reaction of benzyl cyanide with potassium superoxide in the presence of 18-crown-6. Similarly, 4-methylbenzyl cyanide, 4-methoxybenzyl cyanide and 4-chlorobenzyl cyanide gave the corresponding alpha-(4-methylbenzoyl)-4-methylbenzyl cyanide, alpha-(4-methoxybenzoyl)-4-methoxybenzyl cyanide and alpha-(4-chlorobenzoyl)-4-chlorobenzyl cyanide in 25-43% isolated yields under the same reaction conditions. Benzoic, p-toluic, 4-methoxybenzoic and 4-chlorobenzoic acids were also formed in these reactions. No reaction was observed when the mixture was simply stirred. Reflux instead of sonication gave lower yields of the products. However, alpha-alkylbenzyl cyanide produced a high yield of the phenylalkyl ketones when stirred. Interestingly, the corresponding benzoic acid was not formed in these reactions. Possible mechanisms for the formation of alpha-benzoylbenzyl cyanide from benzyl cyanide and phenylalkyl ketones from alpha-alkylbenzyl cyanide are also proposed.
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Sun Y, Park MK, Kim J, Diamond B, Solomon A, Nahm MH. Repertoire of human antibodies against the polysaccharide capsule of Streptococcus pneumoniae serotype 6B. Infect Immun 1999; 67:1172-9. [PMID: 10024557 PMCID: PMC96443 DOI: 10.1128/iai.67.3.1172-1179.1999] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We examined the repertoire of antibodies to Streptococcus pneumoniae 6B capsular polysaccharide induced with the conventional polysaccharide vaccine in adults at the molecular level two ways. In the first, we purified from the sera of seven vaccinees antipneumococcal antibodies and determined their amino acid sequences. Their VH regions are mainly the products of VH3 family genes (candidate genes, 3-23, 3-07, 3-66, and 3-74), but the product of a VH1 family gene (candidate gene, 1-03) is occasionally used. All seven individuals have small amounts of polyclonal kappa+ antibodies (Vkappa1 to Vkappa4 families), although kappa+ antibodies are occasionally dominated by antibodies formed with the product of the A27 Vkappa gene. In contrast, lambda+ anti-6B antibodies are dominated by the antibodies derived from one of 3 very similar Vlambda2 family genes (candidate genes, 2c, 2e, and 2a2) and Clambda1 gene product. The Vlambda2(+) antibodies express the 8.12 idiotype, which is expressed on anti-double-stranded-DNA antibodies. In one case, Vlambda is derived from a rarely expressed Vlambda gene, 10a. In the second approach, we studied a human hybridoma (Dob1) producing anti-6B antibody. Its VH region sequence is closely related to those of the 3-15 VH gene (88% nucleotide homology) and JH4 (92% homology). Its VL region is homologous to the 2a2 Vlambda2 gene (91%) and Jlambda1/Clambda1. Taken together, the V region of human anti-6B antibodies is commonly formed by a VH3 and a Vlambda2 family gene product.
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