201
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Kim JH, Lee SD, Han JM, Lee TG, Kim Y, Park JB, Lambeth JD, Suh PG, Ryu SH. Activation of phospholipase D1 by direct interaction with ADP-ribosylation factor 1 and RalA. FEBS Lett 1998; 430:231-5. [PMID: 9688545 DOI: 10.1016/s0014-5793(98)00661-9] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Phospholipase D1 (PLD1) is known to be activated by ADP-ribosylation factor 1 (ARF1). We report here that ARF1 co-immunoprecipitates with PLD1 and that the ARF1-dependent PLD activation is induced by the direct interaction between ARF1 and PLD1. We found that RalA, another member of the small GTP-binding proteins, synergistically enhances the ARF1-dependent PLD activity with an EC50 of about 30 nM. Using in vitro binding assay, we show that ARF1 and RalA directly interact with different sites of PLD1. The results suggest that the independent interactions of RalA and ARF1 with PLD1 are responsible for the synergistic activation.
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Affiliation(s)
- J H Kim
- Department of Life Science and School of Environmental Engineering, Pohang University of Science and Technology, South Korea
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202
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Kim BC, Ha KS, Park JB, Kim JH. Evidence for role of phospholipase A2 in phosphatidic acid-induced signaling to c-fos serum response element activation. Biochem Biophys Res Commun 1998; 247:630-5. [PMID: 9647745 DOI: 10.1006/bbrc.1998.8855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The activity of exogenous phosphatidic acid (PA) to transactivate c-fos serum response element (SRE) was investigated by transient transfection analysis. Incubation of Rat-2 fibroblast cells with exogenous PA caused a stimulation of c-fos SRE-linked luciferase activity in a dose- and time-dependent manner. The SRE stimulation by PA was dramatically reduced by either pre-treatment with mepacrine, an inhibitor of phospholipase A2 (PLA2), or co-transfection with antisense cytosolic phospholipase A2 (cPLA2) oligonucleotide, whereas lysophosphatidic acid (LPA)-induced SRE activation was not affected. Consistent with this specific requirement for PLA2 by PA, the translocation of cPLA2 protein was rapidly induced followed by PA treatment. Together, these results suggest that PLA2, especially cPLA2, plays a critical role in the nuclear signaling cascade of PA in Rat-2 fibroblast cells.
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Affiliation(s)
- B C Kim
- Department of Molecular and Cellular Genetics, Hallym University, Chun-Cheon, Kangwon-do, Korea
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203
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Jung HY, Kang UG, Joo YH, Cho SC, Jeon SH, Park JB, Kim YS. Electroconvulsive shock does not induce c-fos and junB, but TIS1 and TIS8/zif-268, in neonatal rat hippocampus. Brain Res Dev Brain Res 1998; 108:303-6. [PMID: 9693807 DOI: 10.1016/s0165-3806(98)00066-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The induction in the animal brain of immediate early genes (IEGs) is known to be age-dependent, and it was suggested that, during neonatal period, signaling pathways for the induction of IEGs are immature. In this study, we investigated the induction of various IEGs in neonatal rat hippocampus after electroconvulsive shock (ECS). ECS did not induce c-fos and junB in the hippocampus of 7-day-old rat, but these genes were weakly induced at postnatal 14 days and to an adult level at postnatal 21 days; two other IEGs, TIS1 (NGFI-B, nur77) and TIS8 (zif-268, Egr-1, Krox-24, NGFI-A), were induced at postnatal 7 days, however. Our results suggested that during the neonatal period, signaling pathways for TIS1 and TIS8 induction in rat hippocampus after ECS are complete, while those for c-fos and junB are immature.
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MESH Headings
- Animals
- Animals, Newborn
- DNA-Binding Proteins/analysis
- DNA-Binding Proteins/genetics
- Early Growth Response Protein 1
- Electroshock
- Gene Expression Regulation, Developmental/physiology
- Genes, Immediate-Early/physiology
- Hippocampus/chemistry
- Hippocampus/growth & development
- Immediate-Early Proteins
- Male
- Nuclear Receptor Subfamily 4, Group A, Member 1
- Proto-Oncogene Proteins c-fos/analysis
- Proto-Oncogene Proteins c-fos/genetics
- Proto-Oncogene Proteins c-jun/analysis
- Proto-Oncogene Proteins c-jun/genetics
- RNA, Messenger/analysis
- Rats
- Rats, Sprague-Dawley
- Receptors, Cytoplasmic and Nuclear
- Receptors, Steroid/analysis
- Receptors, Steroid/genetics
- Transcription Factors/analysis
- Transcription Factors/genetics
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Affiliation(s)
- H Y Jung
- Department of Psychiatry, Seoul National University College of Medicine, South Korea
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204
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Abstract
Glyoxalase (GLO) II, which is a component of GLO system and catalyze the conversion of S-lactoyl-glutathione to D-lactate, was purified 1488 fold from rat liver by two steps of Affigel blue and carbobenzoxyglutathione-Sepharose 4B affinity chromatography. The molecular weight of the enzyme was estimated to be 29 kDa which is similar to those from other species. The sequence of N-terminal 9 amino acid residues was determined to be MGIRLLPAT. This was then used to synthesize degenerative primers. cDNA clone was isolated by first synthesizing cDNA from RNA and then PCR amplification. The sequence of cDNA clone was determined by serial sequencing analysis.
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Affiliation(s)
- M Y Cho
- Department of Biochemistry, Medical College, Hallym University
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205
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Cho ZH, Chung SC, Jones JP, Park JB, Park HJ, Lee HJ, Wong EK, Min BI. New findings of the correlation between acupoints and corresponding brain cortices using functional MRI. Proc Natl Acad Sci U S A 1998; 95:2670-3. [PMID: 9482945 PMCID: PMC19456 DOI: 10.1073/pnas.95.5.2670] [Citation(s) in RCA: 317] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A preliminary study of the correlation between acupuncture points (acupoints) for the treatment of eye disorders suggested by ancient Oriental literature and the corresponding brain localization for vision described by Western medicine was performed by using functional MRI (fMRI). The vision-related acupoint (VA1) is located in the lateral aspect of the foot, and when acupuncture stimulation is performed there, activation of occipital lobes is seen by fMRI. Stimulation of the eye by directly using light results in similar activation in the occipital lobes by fMRI. The experiment was conducted by using conventional checkerboard 8-Hz light-flash stimulation of the eye and observation of the time-course data. This was followed by stimulation of the VA1 by using the same time-course paradigm as visual light stimulation. Results obtained with 12 volunteers yielded very clean data and very close correlations between visual and acupuncture stimulation. We have also stimulated nonacupoints 2 to 5 cm away from the vision-related acupoints on the foot as a control, and activation in the occipital lobes was not observed. The results obtained demonstrate the correlation between activation of specific areas of brain cortices and corresponding acupoint stimulation predicted by ancient acupuncture literature.
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Affiliation(s)
- Z H Cho
- Department of Radiological Sciences, Psychiatry, and Human Behavior, University of California, Irvine, CA 92697, USA.
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206
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Abstract
OBJECTIVES Micromechanical retention from the hybrid layer is generally believed to be the mechanism of adhesion of current generation dentin bonding agents. The purpose of this investigation is to evaluate the interfacial fracture toughness of a commercial dentin bonding agent with and without this hybrid layer. METHODS Ten extracted molars (AB2) were flattened on the occlusal surface, All-Bond 2 Universal Adhesive System (Bisco) was applied according to manufacturer's directions and a resin composite (Prodigy, Kerr) crown was formed. Another group of ten molars (AB2Cl) was handled identically with the exception of a 1 min gentle scrubbing application of 5.25% sodium hypochlorite after acid etching to remove the acid-exposed collagen. Plane-strain chevron-notch short bar fracture toughness specimens were fabricated from all 20 composite crowns and tested according to ASTM E1304-89. Each group was tested to failure in tensile mode at 0.1 mm min-1 and the maximum load at failure was used to determine plane-strain fracture toughness (KQvM). Weibull parameters were calculated and fracture probability distributions were tested for significant difference at the 95% confidence level. Scanning electron microscopy was employed on broken specimens (18/20) to describe the failure mode. RESULTS Weibull distributions were not significantly different with characteristic plane-strain fracture toughness from maximum load (KQvM0) of 0.97 MPa m1/2 and 0.81 MPa m1/2 and a Weibull modulus of 4.7 and 3.9, respectively, for AB2 and AB2Cl. All AB2 samples failed within the adhesive joint, while the AB2Cl crack propagated from the interphase of adhesive resin and dentin to 1-2 microns into dentin. SIGNIFICANCE Under the conditions of this study, the presence of collagen did not contribute to a significantly stronger bonded joint. Interfacial fracture toughness evaluation of the dentin-resin composite bimaterial interface shows promise for future investigations.
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Affiliation(s)
- S R Armstrong
- Dows Institute for Dental Research, University of Iowa, Iowa City, USA.
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207
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Smith MR, Court DW, Kim HK, Park JB, Rhee SG, Rhim JS, Kung HF. Overexpression of phosphoinositide-specific phospholipase Cgamma in NIH 3T3 cells promotes transformation and tumorigenicity. Carcinogenesis 1998; 19:177-85. [PMID: 9472710 DOI: 10.1093/carcin/19.1.177] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Phosphoinositide-specific phospholipase Cgamma (PLCgamma) is a key regulatory enzyme that binds to the phosphoryl-tyrosine residues in the cytoplasmic domain of certain activated receptors and catalyses the hydrolysis of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] forming IP3 and diacylglycerol (DAG) in response to several mitogenic factors. Previously, we determined that microinjected PLCgamma induces DNA synthesis in G0-arrested NIH 3T3 cells, suggesting the possibility that PLCgamma may have an oncogenic potential. In this report, we demonstrate that overexpression of PLCgamma in NIH 3T3 cells results in altered growth properties and cellular transformation. The PLCgamma/3T3 transfectants do not require serum growth factors to proliferate, display anchorage-independent growth in soft agar and induce tumors when transplanted into nude mice. These findings suggest that overexpression of PLCgamma facilitates the transformation of NIH 3T3 cells. Furthermore, PLCgamma expression and activity have been shown to be elevated in many human tumors. Thus, PLCgamma signaling may contribute to the promotion and/or progression of human cancers.
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Affiliation(s)
- M R Smith
- Intramural Research Support Program, SAIC Frederick, Laboratory of Biochemical Physiology, National Cancer Institute, Frederick Cancer Research and Development Center, MD 21702, USA.
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208
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Frigstad JR, Kang YH, Park JB. Reinforcement of PMMA bone cement with a continuous wire coil--a canine femur study. Biomed Mater Eng 1997; 7:245-51. [PMID: 9408576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The hoop and axial strains present due to loading after femoral stem implantation in canine femurs, implanted with and without a wire coil surrounding the distal tip were investigated. One stem served as the control without wire coil while the other was experimental reinforced with a wire coil. Both stems were implanted by identical methods. Ideally, the wire coil should serve to reduce the hoop and axial strains present in the distal tip of the arthroplasty. The strains were measured using 90 degrees rosette strain gages. Though the coil's position was altered slightly during implantation usable results were still obtained. At a maximum load of 44.5 N there were 32 and 19% reduction in the hoop and axial strains for the reinforced stem and the control, respectively. This experiment presents a striking difference between the control and reinforced hip arthroplasties. Equally important is that this study confirms the trends in hoop and axial strain behavior demonstrated in other works utilizing a wire coil reinforcement scheme. The simple method of applying a continuous wire coil may help to reduce the loosening of femoral stem of total hip arthroplasty by reducing strains at the tip of the stem due to the strengthening of the cement mantle.
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Affiliation(s)
- J R Frigstad
- Department of Biomedical Engineering, College of Engineering, University of Iowa, Iowa City 52242, USA
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209
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Abstract
Ferromagnetic materials with low Curie temperatures are being investigated for use as interstitial implants for fractionated hyperthermia treatment of prostatic disease. Previous investigations of the system have utilized alloys, such as NiCu, with inadequate corrosion resistance, requiring the use of catheters for removal of the implants following treatment or inert surface coatings which may interfere with thermal characteristics of the implants. We are evaluating a palladium-cobalt (PdCo) binary alloy which is very similar to high palladium alloys used in dentistry. Electrochemical corrosion tests and immersion tests at 37 degrees C for both NiCu and PdCo alloy samples in mammalian Ringer's solution were performed. Long-term corrosion rates are 5.8 x 10(-5) microm per year (NiCu) and 7.7 x 10(-8) microm per year (PdCo) from average immersion test results, indicating higher corrosion resistance of PdCo (P < 0.02); immersion corrosion rates were much lower than initial corrosion rates found electrochemically. Both alloys had significantly lower corrosion rates than standard surgical implant rates of 0.04 microm per year (P < 0.001 for both alloys). Scanning electron microscopy illustrates changes in the NiCu alloy surface due to pitting corrosion; no difference is observed for PdCo. The data indicate that the PdCo alloy may be suitable as a long-term implant for use in fractionated hyperthermia.
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Affiliation(s)
- J A Paulus
- Department of Pathology, University of Iowa, Iowa City 52242, USA
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210
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Abstract
AIM autoimmune hepatitis (AIH) is thought to present rarely in old people. The aims of the present study were to (i) review individuals diagnosed clinically as having AIH presenting over or under 65 years of age at Freeman Hospital, Newcastle, from 1979 to 1993 and (ii) compare diagnostic and histological scores, treatment and outcome, and hence provide a useful profile of the disease in older patients. METHODS 310 individuals with a histological diagnosis of chronic hepatitis were identified, and review of the medical notes of 286 revealed 54 with a diagnosis of AIH. Of these, 12 (22%) were > or =65 years of age at presentation. RESULTS at presentation, the mean diagnostic score (according to the diagnostic scoring system devised by an international panel; maximum score, 17) of the whole group was 11.5 (SD 3.5) and the mean score for those > or =65 years was 9 (SD 3). The mean histological grade (intensity of necro-inflammatory activity; maximum, 18) for the elderly group was 6 (SD 2) compared with 4.5 (SD 0.5) for the whole group. Despite this, 42% of the elderly sufferers had received no immunosuppressive therapy (versus 12% of the younger group). At follow-up, 26% in both groups had developed cirrhosis. None of the elderly group (but 7% of the younger group) had died from complications of chronic liver disease. CONCLUSION we present data on 12 patients presenting at 65 years and over with AIH. In elderly individuals diagnosis may be more difficult, and treatment appears often to have been withheld. Despite this, and the more severe initial histological grade, the prognosis appeared no worse than in younger, usually correctly treated, patients.
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Affiliation(s)
- J L Newton
- Department of Geriatric Medicine, School of Clinical Medical Sciences, The Medical School, Newcastle upon Tyne, UK
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211
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Abstract
A genomic clone for the human glutaredoxin gene was isolated and sequenced. An intron was located within the coding region and began 211 nt downstream of the initiator codon. Except for this intron, the genomic sequence shares 100% identity to the published glutaredoxin cDNA sequence. A second intron was located in the 3' UTR 6 bp downstream of the terminator codon. The tsp of the glutaredoxin gene was determined by primer extension and confirmed by S1 mapping analysis. Analysis of the 5'-flanking region of the gene revealed that the promoter sequences TATA and CCAAT were 30 and 160 bp upstream, respectively, from the tsp. Other potential transcription factor binding sites included NF-E1, HNF-5, P2II and AP-1. Glutaredoxin promoter constructs inserted into a reporter plasmid for firefly luciferase were transfected into fibroblasts, and luciferase activity was 8-10-fold higher compared with controls lacking glutaredoxin promoter. These data indicate that the promoter region of the isolated glutaredoxin gene is functional.
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Affiliation(s)
- J B Park
- Molecular and Clinical Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1372, USA
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212
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Lee TG, Park JB, Lee SD, Hong S, Kim JH, Kim Y, Yi KS, Bae S, Hannun YA, Obeid LM, Suh PG, Ryu SH. Phorbol myristate acetate-dependent association of protein kinase C alpha with phospholipase D1 in intact cells. Biochim Biophys Acta 1997; 1347:199-204. [PMID: 9295164 DOI: 10.1016/s0005-2760(97)00083-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A phospholipase D1 (PLD1) was purified from rat brain by the use of antibody-coupled protein A Sepharose. We found that protein kinase C alp (PKCalpha) stimulated PLD1 activity in the presence of phorbol myristate acetate (PMA). PMA-dependent association of PKCalpha with PLD1 was verified in NIH-3T3 fibroblast cells, and COS7 cells transiently expressing PLD1 as well as in vitro suggesting that the activation of PLD1 resulted from direct association of PKCalpha with PLD1.
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Affiliation(s)
- T G Lee
- Department of Life Science, Pohang University of Science and Technology, South Korea
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213
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Abstract
The GTPase Rab3A has been postulated to cycle on and off synaptic membranes during the course of neurotransmission. Moreover, a Rab guanine nucleotide dissociation inhibitor has been shown to cause Rab3A to dissociate from synaptic membranes in vitro. We demonstrate here that Ca2+/calmodulin also can cause Rab3A to dissociate from synaptic membranes in vitro. Like Rab guanine nucleotide dissociation inhibitor, it forms a 1:1 complex with Rab3A that requires both the lipidated C terminus of Rab3A and the presence of bound guanine nucleotide. In addition, a synthetic peptide corresponding to the Lys62-Arg85 sequence of Rab3A can prevent the dissociating effect of each protein and disrupt complexes between each protein and Rab3A. However, Ca2+/calmodulin's effect differs from that of Rab guanine nucleotide dissociation inhibitor not only in being Ca2+-dependent but also in having a less stringent requirement for GDP as opposed to GTP and in involving a less complete dissociation of Rab3A. The functional significance in vivo of Ca2+/calmodulin's effect remains to be determined; it may depend in part on the relative amounts of Ca2+/calmodulin and Rab guanine nucleotide dissociation inhibitor that are available for binding to Rab3A in individual, activated nerve termini.
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Affiliation(s)
- J B Park
- Howard Hughes Medical Institute, Department of Medicine, University of Washington, Seattle, Washington 98195-7370, USA
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214
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Abstract
This case documents the finding of a spontaneous plaque rupture with thrombus formation in the left main coronary artery of a patient who presented with an infarction of the circumflex artery. This serendipitous observation supports the hypothesis that spontaneous plaque ruptures occur sporadically and do not necessarily lead to occlusion.
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Affiliation(s)
- J B Park
- Department of Medicine, University of California, Irvine, USA
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215
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Jeon SH, Seong YS, Juhnn YS, Kang UG, Ha KS, Kim YS, Park JB. Electroconvulsive shock increases the phosphorylation of cyclic AMP response element binding protein at Ser-133 in rat hippocampus but not in cerebellum. Neuropharmacology 1997; 36:411-4. [PMID: 9175622 DOI: 10.1016/s0028-3908(97)00047-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
ECS increased the Ser-133 phosphorylation of CREB in rat hippocampus, but not in the cerebellum, even though the basal level of phosphorylated CREB was higher in cerebellum. These results indicate that c-fos induction after ECS may be mediated by Ser-133 phosphorylation of CREB in rat hippocampus, but not in the cerebellum.
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Affiliation(s)
- S H Jeon
- Department of Biochemistry, Seoul National University College of Medicine, Korea
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216
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Kwon SY, Kim YS, Woo YK, Kim SS, Park JB. Hydroxyapatite impregnated bone cement: in vitro and in vivo studies. Biomed Mater Eng 1997; 7:129-40. [PMID: 9262826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Hydroxyapatite (HA) particle impregnated polymethylmethacrylate (PMMA) bone cement was fabricated in order to induce bony tissue ingrowth into the pores left behind by resorption of the HA. The amount of HA was 0%, 10%, and 30% by weight. After mixing the HA with bone cement it was cast in a 4 mm inside diameter glass tube (10 mm long). Each specimen was cut into half and used for in vitro and in vivo experiment. Diametral tensile and flexural bend tests were made to evaluate its mechanical properties. SEM (scanning electron microscope) and ESCA (electron spectroscopy for chemical analysis) were used to evaluate the surface characteristics of the specimen. Push-out test and histology studies were made after implanting the specimens for six weeks in the distal portion of rabbit femur. The mechanical test results showed significant decrease of the flexural and diametral tensile strength linear with the increased amount of HA (p < 0.05). The SEM and ESCA analyses showed no definite exposure of HA particles on the surface of the specimens due to the covering by PMMA. The interfacial shear strength of the implanted specimens showed significant increases in the 30% HA specimens compared with the 0% ones but the 10% specimens did not show any difference. Histological observation showed little HA particle apposition to new bone in 10% specimens but more in the 30% ones. In conclusion, this study showed the decreased mechanical properties both by increasing the amount of HA particles and with the bone particles impregnated bone cement. In vivo study showed much lower interfacial shear strength due to implant site compared to other studies but the 30% HA specimens showed statistically significant increase in the push-out strength after implanting into the distal end of rabbit femora.
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Affiliation(s)
- S Y Kwon
- Department of Orthopedic Surgery, Catholic University Medical College, Seoul, Korea
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217
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Jung HY, Kang UG, Ahn YM, Joo YH, Park JB, Kim YS. Induction of tetradecanoyl phorbol acetate-inducible sequence (TIS) genes by electroconvulsive shock in rat brain. Biol Psychiatry 1996; 40:503-7. [PMID: 8879470 DOI: 10.1016/0006-3223(95)00430-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We studied the induction of tetradecanoyl phorbol acetate-inducible sequences (TIS)1, 7, 8, 11, and 21 in rat cerebral cortex, hippocampus, and cerebellum after electroconvulsive shock (ECS). These genes were reported to be induced by depolarization in PC-12 cells. Single ECS induced TIS1, 8, 11, and 21, but not TIS7 genes in the rat brain regions examined. In cerebral cortex and hippocampus, induction of TIS1, TIS8, and TIS21 reached peak at 30 or 45 min after ECS. The induced mRNA of TIS1 and 21 decreased rapidly and returned almost to the basal level by 90 min after ECS, whereas those of TIS8 and 11 lasted longer. In cerebellum, TIS genes were induced and disappeared more rapidly than in the other two regions. The 10 and 20 daily ECSs did not affect the inducibility of TIS1, 11, and 21 in cerebellum, but the induction of TIS8 was attenuated by 35% after 20 daily ECSs. Our study indicated that ECS could induce some of the TIS genes in various rat brain regions, but the induction patterns were different depending on the TIS genes and brain regions. Our study also suggested that chronic ECS could not attenuate the induction of some immediate early genes.
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Affiliation(s)
- H Y Jung
- Department of Psychiatry, Seoul National University College of Medicine, Korea
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218
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Park JB, Levine M. Purification, cloning and expression of dehydroascorbic acid-reducing activity from human neutrophils: identification as glutaredoxin. Biochem J 1996; 315 ( Pt 3):931-8. [PMID: 8645179 PMCID: PMC1217296 DOI: 10.1042/bj3150931] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Dehydroascorbic acid-reducing activity in normal human neutrophil lysates was characterized and identified by activity-based purification and measurement of newly synthesized ascorbate by HPLC. The initial reducing activity was non-dialysable and could not be accounted for by the activity of glutathione as a reducing agent. The reducing activity was purified to homogeneity as an 11 kDa protein. The protein had a specific activity of 3 mumol/min per mg of protein and was glutathione dependent. Kinetic experiments showed that the protein had a K(m) for glutathione of 2.0 mM and a K(m) for dehydroascorbic acid of 250 microM. Dehydroascorbic acid reduction by the purified protein was pH dependent and was maximal at pH 7.5. Peptide fragments from the purified protein were analysed for amino acid sequence and the protein was identified as glutaredoxin. By using degenerate oligonucleotides based on the amino acid sequence, glutaredoxin was cloned from a human neutrophil library. Expressed purified glutaredoxin displayed reducing activity and kinetics that were indistinguishable from those of native purified enzyme. Several approaches indicated that glutaredoxin was responsible for the most of the protein-mediated dehydroascorbic acid reduction in lysates. From protein purification data, glutaredoxin was responsible for at least 47% of the initial reducing activity. Dehydroascorbic acid reduction was at least 5-fold greater in neutrophil lysates than in myeloid tumour cell lysates, and glutaredoxin was detected in normal neutrophil lysates but not in myeloid tumour cell lysates by Western blotting. Glutaredoxin inhibitors inhibited dehydroascorbic acid reduction in neutrophil lysates as much as 80%. These findings indicate that glutaredoxin plays a major role in dehydroascorbic acid reduction in normal human neutrophil lysates, and represent the first identification of dehydroascorbic acid reductase in human tissue by activity-based purification.
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Affiliation(s)
- J B Park
- Laboratory of Cell Biology and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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219
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Levine M, Conry-Cantilena C, Wang Y, Welch RW, Washko PW, Dhariwal KR, Park JB, Lazarev A, Graumlich JF, King J, Cantilena LR. Vitamin C pharmacokinetics in healthy volunteers: evidence for a recommended dietary allowance. Proc Natl Acad Sci U S A 1996; 93:3704-9. [PMID: 8623000 PMCID: PMC39676 DOI: 10.1073/pnas.93.8.3704] [Citation(s) in RCA: 814] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Determinants of the recommended dietary allowance (RDA) for vitamin C include the relationship between vitamin C dose and steady-state plasma concentration, bioavailability, urinary excretion, cell concentration, and potential adverse effects. Because current data are inadequate, an in-hospital depletion-repletion study was conducted. Seven healthy volunteers were hospitalized for 4-6 months and consumed a diet containing <5 mg of vitamin C daily. Steady-state plasma and tissue concentrations were determined at seven daily doses of vitamin C from 30 to 2500 mg. Vitamin C steady-state plasma concentrations as a function of dose displayed sigmoid kinetics. The steep portion of the curve occurred between the 30- and 100-mg daily dose, the current RDA of 60 mg daily was on the lower third of the curve, the first dose beyond the sigmoid portion of the curve was 200 mg daily, and complete plasma saturation occurred at 1000 mg daily. Neutrophils, monocytes, and lymphocytes saturated at 100 mg daily and contained concentrations at least 14-fold higher than plasma. Bioavailability was complete for 200 mg of vitamin C as a single dose. No vitamin C was excreted in urine of six of seven volunteers until the 100-mg dose. At single doses of 500 mg and higher, bioavailability declined and the absorbed amount was excreted. Oxalate and urate excretion were elevated at 1000 mg of vitamin C daily compared to lower doses. Based on these data and Institute of Medicine criteria, the current RDA of 60 mg daily should be increased to 200 mg daily, which can be obtained from fruits and vegetables. Safe doses of vitamin C are less than 1000 mg daily, and vitamin C daily doses above 400 mg have no evident value.
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Affiliation(s)
- M Levine
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1372, USA
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Paulus JA, Richardson JS, Tucker RD, Park JB. Evaluation of inductively heated ferromagnetic alloy implants for therapeutic interstitial hyperthermia. IEEE Trans Biomed Eng 1996; 43:406-13. [PMID: 8626189 DOI: 10.1109/10.486260] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ferromagnetic alloys heated by magnetic induction have been investigated as interstitial hyperthermia delivery implants for over a decade, utilizing low Curie temperatures to provide thermal self-regulation. The minimally invasive method is attractive for fractionated thermal treatment of tumors which are not easily heated by focused microwave or ultrasound techniques. Past analyses of ferromagnetic seeds by other authors depict poor experimental correlation with theoretical heating predictions. Improvements in computer hardware and commercially available finite element analysis software have simplified the analysis of inductively heated thermal seeds considerably. This manuscript examines end effects of finite length implants and nonlinear magnetic material properties to account for previous inconsistencies. Two alloys, Ni-28 wt% Cu (NiCu) and Pd-6.15 wt% Co (PdCo), were used for comparison of theoretical and experimental calorimetric results. Length to diameter (L/d) ratios of over 20 for cylindrical seeds are necessary for minimization of end effects. Magnetic properties tested for alloys of NiCu and PdCo illustrate considerable nonlinearity of these materials in field strength ranges used for induction heating. Field strength dependent magnetic permeabilities and calorimetric data illustrate that more detailed material information must be included to accurately estimate induction power loss for these implants.
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Affiliation(s)
- J A Paulus
- Department of Pathology, University of Iowa, Iowa City 52242, USA.
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221
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Abstract
Urease is an important virulence factor of pathogenicity of gastric Helicobacter pylori. The inhibition of H. pylori urease by the novel proton pump inhibitor, rabeprazole, was investigated kinetically. It was found to act as an irreversible noncompetitive inhibitor of the enzyme. The inhibitory potency of rabeprazole was dependent on the pH of reaction mixture and its Ki values were 0.14 microM (pH 5.0), 0.34 microM (pH 7.0) and 6.10 microM (pH 8.5). Progressive inactivation of urease by rabeprazole initially proceeded according to pseudo-first-order kinetics with respect to the remaining enzymatic activity at pH 7.0 and 37 degrees C, with a second-order rate constant of 0.0017 microM-1 s-1. When the inactivation half-life was plotted versus the reciprocal of the rabeprazole concentration, a straight line was obtained with a slope of -3.12. From an Arrhenius-plot of the temperature-dependence of the inactivation (over the range of 5-37 degrees C), an activation energy of 13.2 kcal/mol was calculated. Recovery of activity was incomplete for H. pylori urease inhibited by rabeprazole, suggesting that the rabeprazole-urease complex is very stable.
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Affiliation(s)
- J B Park
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan
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222
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Kim JK, Park JB. Fatigue properties and stem subsidence in wire coil reinforced PMMA bone cement: a preliminary in vitro study. Biomed Mater Eng 1996; 6:453-62. [PMID: 9138655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The longevity of the cemented total hip joint replacement depends on the integrity of the cement fixation with respect to the interfaces of the metal stem and bone, and stress/strain transmission and its distribution. A simple stainless steel wire coil was placed around a tapered stem in a simulated cement mantle to counteract radial- and hoop-stress and dynamic compression-compression tests were performed. The results showed that the wire coil reinforced cement group had a higher fatigue (30%) and strength (35%) up to 10(5) loading cycles. The amount of stem subsidence during fatigue tests of the wire reinforced group was significantly reduced (2.5 times) compared with the control group.
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Affiliation(s)
- J K Kim
- Department of Biomedical Engineering, College of Engineering, University of Iowa, Iowa, City 52242, USA
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223
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Frigstad JR, Park JB. Reinforcement of PMMA bone cement with a continuous wire coil--a 3D finite element study. Biomed Mater Eng 1996; 6:429-39. [PMID: 9138653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The changes in the mechanical response of a bone cement reinforcement, comprised of a continuous stainless steel coil imbedded within the PMMA bone cement matrix surrounding the distal tip of the total hip arthroplasty, was investigated. To achieve this, a 3D finite element model depicting two and one half rotations of the coil imbedded within the cement at the distal tip was constructed. Ideally, the wire coil should reduce the radial, and to a greater extent, the hoop stresses developing within the cement and at the cement-stem interface. As a means of comparison, a control model of only bone cement was also built. For the radial stresses, the control had about 4.5 times the compressive stress of the reinforced models (0.039 (+/-0.00065) MPa vs. 0.0087 (+/-0.0012) MPa) at the cement-stem interface. The tensile hoop stresses were also 4.5 times higher (4.272 (+/-0.0147) MPa and 0.95 (+/-0.0052) MPa) for the control than for the reinforced models. This indicates that the wire coil reinforcement is effective in reducing the cement mantle's radial and, more importantly, the hoop stresses which may lead to the failure of both the cement and the implant as a whole.
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Affiliation(s)
- J R Frigstad
- Department of Biomedical Engineering, College of Engineering, University of Iowa, Iowa City 52242, USA
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224
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Abstract
Although the recommended dietary allowance provides an estimate for vitamin C ingestion in humans, optimal vitamin C requirements are unknown. We define optimal vitamin C requirements operationally based on the following: dose-function relations, availability in the food supply, steady state concentrations in plasma and tissues achieved at each dose of vitamin C, urinary excretion, bioavailability, toxicity, and epidemiologic observations. Optimal vitamin C requirements can be estimated when information is available for at least some of these criteria.
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Affiliation(s)
- M Levine
- Laboratory of Cell Biology and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0850, USA
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225
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Shin CJ, Kim YS, Park JB, Juhnn YS. Changes in G protein levels in the hippocampus and the striatum of rat brain after chronic treatment with haloperidol and sulpiride. Neuropharmacology 1995; 34:1335-8. [PMID: 8570031 DOI: 10.1016/0028-3908(95)00117-o] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Treatment with either haloperidol or sulpiride for 14 days increased the levels of Gs alpha and Gi alpha in the rat hippocampus, but decreased those of Golf alpha and Gi alpha in the rat striatum. Levels of Gq alpha/G11 alpha and Go alpha were not affected by the drugs. These results demonstrate that haloperidol and sulpiride regulate G protein expression in the hippocampus and striatum quite differently.
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Affiliation(s)
- C J Shin
- Department of Psychiatry, Seoul National University College of Medicine, Chongno-gu, Korea
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226
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Abstract
We investigated the inhibitory effects of four gastric proton pump inhibitors (PPIs): rabeprazole, a novel benzimidazole PPI, omeprazole, lansoprazole and AG-2000, on the urease activity of Helicobacter pylori (H. pylori). Their 50% inhibitory concentrations (I50s) were found to be 0.29, 5.4, 9.3 and 0.3 microM respectively. Rabeprazole and omeprazole were also potent inhibitors of Jack bean and Proteus mirabilis cellular ureases. The thioether derivative of rabeprazole, one of its metabolites, had no inhibitory effect on H. pylori urease, despite being reported as a more potent inhibitor of H. pylori growth than rabeprazole. The inhibitory effect of rabeprazole was prevented completely and reversed considerably by the addition of sulfhydryl compounds, such as beta-mercaptoethanol, glutathione and dithiothreitol. Moreover, the addition of beta-mercaptoethanol recovered the urease activity inhibited by rabeprazole. From these results, we expected that rabeprazole inhibited H. pylori urease activity by forming disulfide bonds between it and the active site of the enzyme.
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Affiliation(s)
- M Tsuchiya
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Toyama, Japan
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227
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Lee SD, Park JB, Lee WI, Shim HJ, Lee ED, Lee JJ, Kim WB, Yang J, Kim CK, Lee MG. Pharmacokinetics and antitumour activity of a new anthracycline, DA-125, after intravenous administration to subcutaneously implanted Lewis-lung-carcinoma-bearing mice. Biopharm Drug Dispos 1995; 16:489-505. [PMID: 7579031 DOI: 10.1002/bdd.2510160607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The pharmacokinetics and tissue distribution of M1-M4 were compared after intravenous (i.v.) administration of DA-125, 25 mg kg-1, to BDF1 mice (n = 5 at each sampling time) and subcutaneously implanted Lewis-lung-carcinoma-bearing BDF1 mice (n = 10 at each sampling time. The mean plasma concentrations of M1-M4 were not significantly different between the two groups of mice, and hence similar pharmacokinetic parameters for M1-M4 were obtained. The amount of M1 in the lung was significantly greater in the tumour-bearing mice than in the control mice, resulting in a greater AUAt in the tumour-bearing mice (18,600 against 8940 micrograms min g-1), and vice versa in the liver (962 against 3840 micrograms min g-1). However, the corresponding values for other tissues were comparable between the control and tumour-bearing mice. The amount of M1 was greatest in the lung for up to 2 h in the tumour-bearing mice. M2 was the predominant metabolite among M1-M4 excreted in 24 h urine by both groups of mice; 8.36 and 10.7% of the i.v. dose were excreted in 24 h urine as M2--expressed in terms of DA-125--by the control and tumour-bearing mice, respectively. The amount of M1 in the tumour mass reached a mean Cmax of 3.75 micrograms g-1 immediately after i.v. administration of DA-125 to the tumour-bearing mice, then declined very slowly to an amount that remained almost constant for up to 24 h. This suggested that M1 has high affinity for the subcutaneously implanted Lewis lung carcinoma. The antitumour activity, such as the increase in life span (ILS) and tumour growth inhibition (TGI) of DA-125, 6-48 mg kg-1, and adriamycin (ADM), 3-18 mg kg-1, were also compared in subcutaneously implanted Lewis-lung-carcinoma-bearing BDF1 mice after four weekly i.v. administration of the drugs on days 1,8,15, and 22 following tumour implantation. More than three out of six mice survived as tumour-free for longer than 70 d at a DA-125 dose range of 6-24 mg kg-1, but there were no tumour-free mice at any dose of ADM. Assuming ILS values higher than 30% to be effective, DA-125 doses ranging from 6 to 24 mg kg-1 were effective in increasing the life span, which ADM does only within the dose range of 6-12 mg kg-1.
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Affiliation(s)
- S D Lee
- Research Laboratories, Dong-A Pharmaceutical Company Ltd., Yongin-Gun, Kyunggi-Do, Korea
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228
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Park JB, Matsuura M, Han KY, Norderyd O, Lin WL, Genco RJ, Cho MI. Periodontal regeneration in class III furcation defects of beagle dogs using guided tissue regenerative therapy with platelet-derived growth factor. J Periodontol 1995; 66:462-77. [PMID: 7562336 DOI: 10.1902/jop.1995.66.6.462] [Citation(s) in RCA: 133] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We developed an effective regenerative therapy, referred to as platelet-derived growth factor-BB (PDGF-BB)-modulated guided tissue regenerative (GTR) therapy (P-GTR), capable of achieving periodontal regeneration of horizontal (Class III) furcation defects in the beagle dog. To determine its efficacy, repair and regeneration of horizontal furcation defects by P-GTR therapy and GTR therapy were compared. Chronically inflamed horizontal furcation defects were created around the second (P2) and fourth mandibular premolars (P4). After demineralization of the root surfaces with citric acid, the surfaces of left P2 and P4 were treated with PDGF-BB (P-GTR therapy) and those of contralateral teeth were treated with vehicle only (GTR therapy). Periodontal membranes were placed and retained 0.5 mm above the cemento-enamel junction for both groups. The mucoperiosteal flap was sutured in a coronal position and plaque control was achieved by daily irrigation with 2% chlorhexidine gluconate. At 5, 8, and 11 weeks, two animals each were sacrificed by perfusion with 2.5% glutaraldehyde through the carotid arteries, and the lesions were sliced mesio-distally, demineralized, dehydrated, and embedded. Periodontal healing and regeneration after GTR and P-GTR therapy were compared by histomorphometric as well as morphological analysis. Morphometric analysis for each time period was performed on the pooled samples of P2 and P4. Five weeks after both therapies, the lesions were filled primarily by tissue-free area, epithelium, inflamed tissue, and a small amount of newly formed fibrous connective tissue. At 8 and 11 weeks after P-GTR therapy, there was a statistically greater amount of bone and periodontal ligament formed in the lesions. The newly formed bone filled 80% of the lesion at 8 weeks and 87% at 11 weeks with P-GTR therapy, compared to 14% of the lesion at 8 weeks and 60% at 11 weeks with GTR therapy. Also, with P-GTR therapy there was less epithelium and tissue-free area, less inflamed tissue, and less connective tissue. Morphological analysis indicated that the defects around P2 revealed faster periodontal repair and regeneration than those around P4. While the lesions around P2 were effectively regenerated by 11 weeks even after GTR therapy, those around P4 failed to regenerate. On the other hand, P-GTR therapy further promoted periodontal repair and regeneration so that at 8 weeks the lesions around P2 and P4 demonstrated complete and nearly complete regeneration, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- J B Park
- Department of Oral Biology, School of Dental Medicine, State University of New York, Buffalo, USA
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229
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Welch RW, Wang Y, Crossman A, Park JB, Kirk KL, Levine M. Accumulation of vitamin C (ascorbate) and its oxidized metabolite dehydroascorbic acid occurs by separate mechanisms. J Biol Chem 1995; 270:12584-92. [PMID: 7759506 DOI: 10.1074/jbc.270.21.12584] [Citation(s) in RCA: 113] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
It is unknown whether ascorbate alone (vitamin C), its oxidized metabolite dehydroascorbic acid alone, or both species are transported into human cells. This problem was addressed using specific assays for each compound, freshly synthesized pure dehydroascorbic acid, the specially synthesized analog 6-chloroascorbate, and a new assay for 6-chloroascorbate. Ascorbate and dehydroascorbic acid were transported and accumulated distinctly; neither competed with the other. Ascorbate was accumulated as ascorbate by sodium-dependent carrier-mediated active transport. Dehydroascorbic acid transport and accumulation as ascorbate was at least 10-fold faster than ascorbate transport and was sodium-independent. Once transported, dehydroascorbic acid was immediately reduced intracellularly to ascorbate. The analog 6-chloroascorbate had no effect on dehydroascorbic acid transport but was a competitive inhibitor of ascorbate transport. The Ki for 6-chloroascorbate (2.9-4.4 microM) was similar to the Km for ascorbate transport (9.8-12.6 microM). 6-Chloroascorbate was itself transported and accumulated in fibroblasts by a sodium-dependent transporter. These data provide new information that ascorbate and dehydroascorbic acid are transported into human neutrophils and fibroblasts by two distinct mechanisms and that the compound available for intracellular utilization is ascorbate.
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Affiliation(s)
- R W Welch
- Laboratory of Cell Biology and Genetics, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-0850, USA
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230
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Chung CP, Park JB, Bae KH. Pharmacological effects of methanolic extract from the root of Scutellaria baicalensis and its flavonoids on human gingival fibroblast. Planta Med 1995; 61:150-153. [PMID: 7753922 DOI: 10.1055/s-2006-958036] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The methanolic extract from the root of Scutellaria baicalensis Georgi and its flavonoids, wogonin, baicalein, and baicalin were evaluated for anti-inflammatory action and the activatory effect on gingival fibroblasts. In LPS-induced production of IL-1 beta, three flavonoids at 1 microgram/ml expressed a significant (> 50%) inhibitory effect, similar to that of prednisolone. Moreover, the flavonoids inhibited IL-1 beta-induced synthesis of PGE2 and LTB4 considerably, although the effect of wogonin on LTB4 synthesis was marginal. In addition, three flavonoids exerted a moderate inhibition (33-36%) of collagenolytic activity, comparable to 40% inhibition by tetracycline. Meanwhile, the cellular activity of fibroblasts was augmented remarkably (40%) by baicalein (2) and slightly by baicalin (3) or wogonin (1). Consistent with the cellular activation, flavonoids enhanced the synthesis of both collagen and total protein in fibroblasts, in contrast to growth factors which increased only the synthesis of total protein. Although the effects of the methanolic extract resembled those of the flavonoids, the extract expressed a preferential effect on the synthesis of collagen and total protein.
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Affiliation(s)
- C P Chung
- College of Dentistry, Seoul National University, Korea
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231
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Surh YJ, Ahn SH, Kim KC, Park JB, Sohn YW, Lee SS. Metabolism of capsaicinoids: evidence for aliphatic hydroxylation and its pharmacological implications. Life Sci 1995; 56:PL305-11. [PMID: 8614248 DOI: 10.1016/0024-3205(95)00091-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A new metabolic oxidation pathway of capsaicin (N-[(4-hydroxy-3-methoxyphenyl)-methyl]-8-methyl-(E)-6 -nonenamide), a major pungent and pharmacologically active principle of hot peppers, was investigated. Incubation of capsaicin with phenobarbital-induced rat liver postmitochondrial supernatant enriched with NADPH-generating system produced N-(4,5-dihydroxy-3-methoxybenzyl)-(E)-6 -nonenylamide and a more polar metabolite. The latter metabolite was spectrophotometrically and chromatographically identical to authentic omega-hydroxycapsaicin. This new metabolite was also detected in the urine of rabbits given capsaicin by gastric intubation. Other analogs of capsaicin, such as dihydrocapsaicin and nonivamide, also formed similar metabolites via aliphatic hydroxylation. When tested for antinociceptive activity as well as pungency, the above polar metabolites were found to be inactive while their parent compounds exhibited strong sensory effects. Capsaicin interacted irreversibly with heptic drug metabolizing enzymes, thereby inhibiting their activity as indicated by prolongation of pentobarbital sleeping time in rats. Such inhibition of drug metabolism was not observed with omega-hydroxycapsaicin. These findings suggest that metabolism of capsaicinoids via hydroxylation of their side chains plays an important role in the detoxification of these pharmacologically active substances.
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Affiliation(s)
- Y J Surh
- College of Pharmacy, Seoul National University, Korea
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232
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Park JB, Imamura L, Kobashi K, Itoh H, Miyazaki T, Horisaki T. Inhibitory effect of beta-glucosyl-phenolic hydroxamic acids against urease in the presence of microfloral beta-glucosidase. Biol Pharm Bull 1995; 18:208-13. [PMID: 7742785 DOI: 10.1248/bpb.18.208] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Three glucosyl-phenolic hydroxamates, 4-O-(beta-D-glucopyranosyl) benzohydroxamic acid, 4-O-(beta-D-glucopyranosyl)hippuric hydroxamic acid, and 3-[4-O-(beta-D-glucopyranosyl)phenyl]propionohydroxamic acid (Glc-PPHA), were hydrolyzed to their corresponding aglycones by beta-glucosidase of intestinal flora of rat without any major adverse hydrolysis in vitro. Inhibitory potency of these glucosyl-hydroxamates on urease was recovered to the same extent as that of the corresponding aglycone hydroxamates by preincubation for 2h with rat intestinal flora. p-Hydroxyphenylpropionohydroxamic acid inhibited noncompetitively jack-bean urease activity and its glucose-ligated form, Glc-PPHA inhibited it competitively. A single oral dose of Glc-PPHA tended to inhibit urease activity in proximal colon contents of rat at 6 h after administration (p = 0.06). After 14C-urea was orally administered to rat, 14CO2 was collected for to measure the ureolysis in vivo. Expired 14CO2 was limited to 40% by a single oral dose of Glc-PPHA during 6 h, and 75% of intestinal ureolysis was repressed during the first 1 h in the breath test.
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Affiliation(s)
- J B Park
- Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan
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233
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Kim H, Ko JP, Kang UG, Park JB, Kim HL, Lee YH, Kim YS. Electroconvulsive shock reduces inositol 1,4,5-trisphosphate 3-kinase mRNA expression in rat dentate gyrus. J Neurochem 1994; 63:1991-4. [PMID: 7931359 DOI: 10.1046/j.1471-4159.1994.63051991.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We investigated the expression of inositol 1,4,5-trisphosphate (InsP3) 3-kinase mRNA after a single electroconvulsive shock (ECS) with in situ hybridization histochemistry in rat brain. At 6 h after ECS, the expression was markedly decreased in the dentate gyrus, and the decrease was maintained until 9 h with a slight recovery. The InsP3 3-kinase mRNA content returned to basal levels after 12 h. We could not detect any apparent changes in the expression of InsP3 3-kinase mRNA in the CA1-CA3 areas of hippocampus, the striatum, and the cerebral cortex at any time point examined. In the temporal pattern, the reduction of the expression in the dentate gyrus was preceded by the induction of c-fos after ECS. These observations suggest that the InsP3 3-kinase might be one of the genes whose expression can be altered by ECS.
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Affiliation(s)
- H Kim
- Department of Anatomy, College of Medicine, Korea University, Seoul
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234
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Kang UG, Hong KS, Jung HY, Kim YS, Seong YS, Yang YC, Park JB. Activation and tyrosine phosphorylation of 44-kDa mitogen-activated protein kinase (MAPK) induced by electroconvulsive shock in rat hippocampus. J Neurochem 1994; 63:1979-82. [PMID: 7931356 DOI: 10.1046/j.1471-4159.1994.63051979.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Electroconvulsive shock (ECS) has been reported to induce the phosphorylation and activation of 42-kDa, but not 44-kDa, mitogen-activated protein kinase (MAPK) in rat hippocampus. We studied the activation and tyrosine phosphorylation of MAPKs in rat brain after ECS. We observed the increase of the activities of both 42- and 44-kDa MAPKs in rat hippocampus after ECS. The activities reached peak at 2 min and returned to basal levels by 15 min after ECS. We also observed the increased phosphorylation on the tyrosine residue of 42-kDa MAPK in rat hippocampus after ECS, but not on that of 44-kDa MAPK. However, when we examined the immunoprecipitated 44-kDa MAPK, we could demonstrate that the tyrosine phosphorylation of 44-kDa MAPK at 2 min after ECS was markedly increased, in accordance with the increase of kinase activity. These results indicate that ECS induces the transient activation and tyrosine phosphorylation of 44-kDa MAPK, as well as 42-kDa MAPK, in rat hippocampus, although the amount of tyrosine phosphorylation is far less and the kinase activity is lower in 44-kDa MAPK than in 42-kDa MAPK.
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Affiliation(s)
- U G Kang
- Department of Psychiatry, Seoul National University College of Medicine, South Korea
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235
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Abstract
Mouth guards and materials were tested to provide information for a more protective yet more comfortable product. Ethylene-vinyl acetate copolymer materials varying in thickness and stiffness were tested for their mechanical, thermal, and water-absorption properties. Thickness was measured before and after fabrication of the mouth guard. During fabrication, thicknesses decreased from 25% to 50% for the custom-fabricated mouth guards and 70% to 99% for the mouth-formed (boil-and-bite), off-the-shelf, over-the-counter mouth guards. The thicker the material is, the greater the resulting energy absorption is. It is therefore essential that the thickness in the occlusal portion of the mouth guard remain optimal after fabrication. A mouth guard with a stiffer insert, which softens at a higher temperature in the occlusal portion, is proposed as a more protective mouth guard.
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Affiliation(s)
- J B Park
- Department of Biomedical Engineering, University of Iowa, College of Dentistry, Iowa City
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236
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Kim YS, Hong KS, Seong YS, Park JB, Kuroda S, Kishi K, Kaibuchi K, Takai Y. Phosphorylation and activation of mitogen-activated protein kinase by kainic acid-induced seizure in rat hippocampus. Biochem Biophys Res Commun 1994; 202:1163-8. [PMID: 7519421 DOI: 10.1006/bbrc.1994.2050] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Injection of kainic acid into rat induced a limbic seizure and increased the activities of two protein kinases with Mrs of 42 kDa and 44 kDa in the hippocampus. These two protein kinases were identified as MAP kinases by an anti-MAP kinase antibody. These MAP kinases were phosphorylated at least at a tyrosine residue. The time course of the MAP kinase activation was roughly parallel with that of the seizure. These results indicate that the kainic acid-induced seizure induces MAP kinase activation in rat hippocampus.
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Affiliation(s)
- Y S Kim
- Department of Psychiatry, Seoul National University College of Medicine, Korea
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237
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Yamashita S, Park JB, Ryu PD, Inukai H, Tanifuji M, Murase K. Possible presence of the ATP-sensitive K+ channel in isolated spinal dorsal horn neurons of the rat. Neurosci Lett 1994; 170:208-12. [PMID: 8058189 DOI: 10.1016/0304-3940(94)90320-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The ATP-sensitive K+ channel (KATP channel) is a K+ channel inhibited by cytoplasmic ATP. It was originally found in cardiac cells and recently in neuronal cells. Here, we present evidence indicating that the KATP channel also exists in spinal dorsal horn neurons: membrane currents were recorded by whole-cell voltage-clamp in spinal dorsal horn neurons isolated from young rats. The outward current was augmented by KATP channel activators nicorandil and minoxidil and reduced by the blocker glibenclamide. This glibenclamide-induced change in the current was augmented when the intracellular ATP was lowered and the reversal potential was shifted according to the external K+ concentration.
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Affiliation(s)
- S Yamashita
- Department of Information Science, Fukui University, Japan
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238
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Abstract
Silymarin, a commercial crude drug used as a hepatoprotective, was found to inhibit 53% of beta-glucuronidase activity at a final concentration of 0.8 mg/ml. Of three compounds A, silybin and C, which were isolated from silymarin, A and silybin potently inhibited the enzyme activity, followed by C. beta-Glucuronidases of intestinal bacteria, HGU-1 and HGU-2, and E. coli HB101 were noncompetitively inhibited by silybin. beta-Glucuronidase of the feces of a healthy human and of a human with colon cancer were also inhibited by silybin, silymarin and saccharic acid 1,4-lactone at 0.03-0.15 mg/ml. Silymarin and silybin protected the increase in enzyme activity in the serum of the rats treated with CCl4.
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Affiliation(s)
- D H Kim
- College of Pharmacy, Kyunghee University, Seoul, Korea
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239
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Lim TH, Goel VK, Winterbottom JM, Kessler B, Ahn JY, Gwon JK, Park JB, Weinstein JN. A comparison of stress-induced porosity due to conventional and a modified spinal fixation device. J Spinal Disord 1994; 7:1-11. [PMID: 8186583 DOI: 10.1097/00002517-199407010-00001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A hypothesis that device-related osteopenia can be reduced by decreasing the rigidity of a fixation device was tested through a canine study. Polymer washers were interposed between the integral nut and plate of the variable spinal plating (VSP) system to reduce its rigidity. A solid fusion was observed 6 months postoperatively in all of the animals using VSP or modified systems. The stabilized segment using both systems showed similar load-displacement behaviors immediately after surgery and 6 months postoperatively. Although not significant, 5.6 and 1.8% decreases in volumetric density of mineralized bone were found in the stabilized segments due to VSP and modified systems, respectively. The modified system also increased bone growth around screws. The new concept of using polymer washers, to decrease rigidity of the fixation device over time, may reduce device-related osteopenia.
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Affiliation(s)
- T H Lim
- Department of Orthopaedic Surgery, Medical College of Wisconsin, Milwaukee 53226
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240
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Park JB, Ashizawa K, Parkison C, Cheng SY. One-step immunoaffinity purification of human beta 1 thyroid hormone receptor with DNA and hormone binding activity. J Biochem Biophys Methods 1993; 27:95-103. [PMID: 8227948 DOI: 10.1016/0165-022x(93)90053-q] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
An efficient and versatile method to purify large amounts of active human beta 1 thyroid hormone receptor (h-TR beta 1) was developed. Using a T7 expression system, h-TR beta 1 was overexpressed in Escherichia coli. Approx. 80% of the expressed receptor protein was concentrated in the insoluble inclusion bodies and approximately 20% was in the soluble form (h-TR beta 1-S). h-TR beta 1-S was conveniently purified by one immunoaffinity chromatographic step. From 1 l of cell culture, approx. 0.1 mg of purified h-TR beta 1-S was obtained. The purified h-TR beta 1-S binds to 3,3',5-triiodo-L-thyronine with a Ka = 2 x 10(9) M-1 and exhibits analog specificity. The purified h-TR beta 1-S also binds to T3 response elements (TRE) with different orientation in the half-sites with differential activity. In addition, binding of h-TR beta 1-S to TREs was enhanced by retinoid X receptor. These results indicate that the purified h-TR beta 1-S retains its hormone and DNA binding activity. The purified h-TR beta 1-S is suitable for structural and functional studies. This method could be used to purify h-TR beta 1 or rat TR beta 1 expressed in insect cells or yeast.
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Affiliation(s)
- J B Park
- Laboratory of Molecular Biology, DCBDC, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
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241
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Lee YH, Ryu SH, Suh PG, Park JB, Ahn YM, Kim YS. Tyrosine phosphorylation of PLC-gamma 1 induced by electroconvulsive shock in rat hippocampus. Biochem Biophys Res Commun 1993; 194:665-70. [PMID: 7688221 DOI: 10.1006/bbrc.1993.1873] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
ECS has been shown to increase PIP2 breakdown in rat brain, which suggested the possible activation of PLC-signal transduction system by ECS. When we examined the PLC-gamma 1 immunoprecipitated from rat hippocampal tissues after ECS, we found a rapid increase in phosphotyrosine of PLC-gamma 1, which reached peak at 10 minutes after ECS and returned to basal level after 2 hours. There was no change in the amount of PLC-gamma 1 proteins during that period. The tyrosine phosphorylation induced by ECS didn't affect the enzyme activity when assayed in vitro. These results suggested that ECS may activate PLC-gamma 1 by phosphorylation on tyrosine residue, but without changing enzyme activity itself.
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Affiliation(s)
- Y H Lee
- Department of Life Science, Pohang Institute of Technology, Korea
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242
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Abstract
c-erbB-2 oncogene encodes a growth factor receptor whose amino acid sequence has extensive homology with human epidermal growth factor receptor. It is frequently overexpressed in human breast, ovary, lung, and stomach cancers, where its overexpression is related significantly to the prognosis. Tl investigate the possible role of c-erbB-2 oncogene in the oncogenesis of stomach cancer, we examined the genetic alterations of c-erbB-2 oncogene in 4 stomach cancer cell lines, SNU-1, SNU-5, SNU-16 and KATO III. There were no differences in c-erbB-2 mRNA level as well as c-erbB-2 gene copy number among them. But gp185-erbB-2, c-erbB-2 gene product, was increased from 2- to 4-fold in SNU-1 and SNU-5 cells, compared with that in SNU-16 or KATO III cells. Our results suggest that post-transcriptional regulation of gp185erbB-2 expression may underlie gp185erbB-2 overexpression in cancer cells.
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Affiliation(s)
- C D Bae
- Department of Biochemistry, Seoul National University College of Medicine, Korea
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243
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Henrich DE, Cram AE, Park JB, Liu YK, Reddi H. Inorganic bone and demineralized bone matrix impregnated bone cement: a preliminary in vivo study. J Biomed Mater Res 1993; 27:277-80. [PMID: 8436585 DOI: 10.1002/jbm.820270218] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- D E Henrich
- University of Iowa, College of Medicine, Iowa City
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244
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Paulus JA, Tucker RD, Flanagan SW, Moseley PL, Loening SA, Park JB. Heat shock protein response in a prostate tumor model to interstitial thermotherapy: implications for clinical treatment. Prostate 1993; 23:263-70. [PMID: 8234068 DOI: 10.1002/pros.2990230308] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Hyperthermia is being utilized individually and in conjunction with other therapies in treating malignant and benign tumors, though few studies have examined cellular effects of elevated temperatures in the prostate model. Highly conserved proteins of the 70 kDa heat shock protein family (HSP 70) are produced in response to environmental stresses, including heat, and are found in all organisms. HSPs are an indicator of cell damage, are associated with thermotolerance, and provide cells with transient resistance to subsequent thermal challenges. Transient thermotolerance is important in the determination of temperature, duration, and sequencing for treatments. This preliminary study analyzes the HSP 70 response of the Dunning R3327 adenocarcinoma model to a single 50 degrees C 1 hr treatment. Elevated HSP levels were found between 10 and 16 hr, returning to baseline by 24 hr. As some fractions of the cells are able to produce HSP 70 following treatment, the data suggest that currently utilized clinical temperatures (42-46 degrees C) administered for 1 hr are inadequate. HSP levels in response to hyperthermia, radiation, and chemotherapy may be useful in finding optimal treatment regimens for prostate cancer.
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Affiliation(s)
- J A Paulus
- Department of Biomedical Engineering, University of Iowa, Iowa City 52242
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245
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Klump H, Di Ruggiero J, Kessel M, Park JB, Adams MW, Robb FT. Glutamate dehydrogenase from the hyperthermophile Pyrococcus furiosus. Thermal denaturation and activation. J Biol Chem 1992; 267:22681-5. [PMID: 1429615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Pyrococcus furiosus is a marine hyperthermophile that grows optimally at 100 degrees C. Glutamate dehydrogenase (GDH) from P. furiosus is a hexamer of identical subunits and has an M(r) = 270,000 +/- 5500 at 25 degrees C. Electron micrographs showed that the subunit arrangement is similar to that of GDH from bovine liver (i.e. 3/2 symmetry in the form of a triangular antiprism). However, GDH from P. furiosus is inactive at temperatures below 40 degrees C and undergoes heat activation above 40 degrees C. Both NAD+ and NADP+ are utilized as cofactors. Apparently the inactive enzyme also binds cofactors, since the enzyme maintains the ability to bind to an affinity column (Cibacron blue F3GA) and is specifically eluted with NADP+. Conformational changes that accompany activation and thermal denaturation were detected by precision differential scanning microcalorimetry. Thermal denaturation starts at 110 degrees C and is completed at 118 degrees C. delta(cal) = 414 Kcal [mol GDH]-1. Tm = 113 degrees C. This increase in heat capacity indicates an extensive irreversible unfolding of the secondary structure as evidenced also by a sharp increase in absorbance at 280 nm and inactivation of the enzyme. The process of heat activation of GDH from 40 to 80 degrees C is accompanied by a much smaller increase in absorbance at 280 nm and a reversible increase in heat capacity with delta(cal) = 187 Kcal [mol GDH]-1 and Tm = 57 degrees C. This absorbance change as well as the moderate increase in heat capacity suggest that thermal activation leads to some exposure of hydrophobic groups to solvent water as the GDH structure is opened slightly. The increase in absorbance at 280 nm during activation is only 12% of that for denaturation. Overall, GDH appears to be well adapted to correspond with the growth response of P. furiosus to temperature.
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Affiliation(s)
- H Klump
- Biochemistry Department, University of Cape Town, Rondebosch, South Africa
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246
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Blake PR, Day MW, Hsu BT, Joshua-Tor L, Park JB, Hare DR, Adams MW, Rees DC, Summers MF. Comparison of the X-ray structure of native rubredoxin from Pyrococcus furiosus with the NMR structure of the zinc-substituted protein. Protein Sci 1992; 1:1522-5. [PMID: 1303770 PMCID: PMC2142123 DOI: 10.1002/pro.5560011113] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The three-dimensional X-ray structures of the oxidized and reduced forms of rubredoxin from Pyrococcus furiosus, determined at -161 degrees C, and the NMR structure of the zinc-substituted protein, determined in solution at 45 degrees C, are compared. The NMR and X-ray structures, which were determined independently, are very similar and lead to similar conclusions regarding the interactions that confer hyperthermostability.
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Affiliation(s)
- P R Blake
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County 21228
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247
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Abstract
The fixation of orthopedic implants has been one of the most difficult and challenging problems. The fixation can be achieved via: (a) direct mechanical fixation using screws, pins, wires, etc.; (b) passive or interference mechanical fixation where the implants are allowed to move or merely positioned onto the tissue surfaces; (c) bone cement fixation which is actually a grouting material; (d) biological fixation by allowing tissues to grow into the interstices of pores or textured surfaces of implants; (e) direct chemical bonding between implant and tissues; or (f) any combination of the above techniques. This article is concerned with various fixation techniques including the potential use of electrical, pulsed electromagnetic field, chemical stimulation using calcium phosphates for the enhancement of tissue ingrowth, direct bonding with bone by glass-ceramics and resorbable particle impregnated bone cement to take advantages of both the immediate fixation offered by the bone cement and long term fixation due to tissue ingrowth.
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Affiliation(s)
- J B Park
- Department of Biomedical Engineering, University of Iowa, Iowa City 52242
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248
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Day MW, Hsu BT, Joshua-Tor L, Park JB, Zhou ZH, Adams MW, Rees DC. X-ray crystal structures of the oxidized and reduced forms of the rubredoxin from the marine hyperthermophilic archaebacterium Pyrococcus furiosus. Protein Sci 1992; 1:1494-507. [PMID: 1303768 PMCID: PMC2142115 DOI: 10.1002/pro.5560011111] [Citation(s) in RCA: 173] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The structures of the oxidized and reduced forms of the rubredoxin from the archaebacterium, Pyrococcus furiosus, an organism that grows optimally at 100 degrees C, have been determined by X-ray crystallography to a resolution of 1.8 A. Crystals of this rubredoxin grow in space group P2(1)2(1)2(1) with room temperature cell dimensions a = 34.6 A, b = 35.5 A, and c = 44.4 A. Initial phases were determined by the method of molecular replacement using the oxidized form of the rubredoxin from the mesophilic eubacterium, Clostridium pasteurianum, as a starting model. The oxidized and reduced models of P. furiosus rubredoxin each contain 414 nonhydrogen protein atoms comprising 53 residues. The model of the oxidized form contains 61 solvent H2O oxygen atoms and has been refined with X-PLOR and TNT to a final R = 0.178 with root mean square (rms) deviations from ideality in bond distances and bond angles of 0.014 A and 2.06 degrees, respectively. The model of the reduced form contains 37 solvent H2O oxygen atoms and has been refined to R = 0.193 with rms deviations from ideality in bond lengths of 0.012 A and in bond angles of 1.95 degrees. The overall structure of P. furiosus rubredoxin is similar to the structures of mesophilic rubredoxins, with the exception of a more extensive hydrogen-bonding network in the beta-sheet region and multiple electrostatic interactions (salt bridge, hydrogen bonds) of the Glu 14 side chain with groups on three other residues (the amino-terminal nitrogen of Ala 1; the indole nitrogen of Trp 3; and the amide nitrogen group of Phe 29). The influence of these and other features upon the thermostability of the P. furiosus protein is discussed.
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Affiliation(s)
- M W Day
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125
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249
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Blake PR, Park JB, Zhou ZH, Hare DR, Adams MW, Summers MF. Solution-state structure by NMR of zinc-substituted rubredoxin from the marine hyperthermophilic archaebacterium Pyrococcus furiosus. Protein Sci 1992; 1:1508-21. [PMID: 1303769 PMCID: PMC2142118 DOI: 10.1002/pro.5560011112] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The three-dimensional solution-state structure is reported for the zinc-substituted form of rubredoxin (Rd) from the marine hyperthermophilic archaebacterium Pyrococcus furiosus, an organism that grows optimally at 100 degrees C. Structures were generated with DSPACE by a hybrid distance geometry (DG)-based simulated annealing (SA) approach that employed 403 nuclear Overhauser effect (NOE)-derived interproton distance restraints, including 67 interresidue, 124 sequential (i-j = 1), 75 medium-range (i-j = 2-5), and 137 long-range (i-j > 5) restraints. All lower interproton distance bounds were set at the sum of the van Der Waals radii (1.8 A), and upper bounds of 2.7 A, 3.3 A, and 5.0 A were employed to represent qualitatively observed strong, medium, and weak NOE cross peak intensities, respectively. Twenty-three backbone-backbone, six backbone-sulfur (Cys), two backbone-side chain, and two side chain-side chain hydrogen bond restraints were include for structure refinement, yielding a total of 436 nonbonded restraints, which averages to > 16 restraints per residue. A total of 10 structures generated from random atom positions and 30 structures generated by molecular replacement using the backbone coordinates of Clostridium pasteurianum Rd converged to a common conformation, with the average penalty (= sum of the square of the distance bounds violations; +/- standard deviation) of 0.024 +/- 0.003 A2 and a maximum total penalty of 0.035 A2. Superposition of the backbone atoms (C, C alpha, N) of residues A1-L51 for all 40 structures afforded an average pairwise root mean square (rms) deviation value (+/- SD) of 0.42 +/- 0.07 A. Superposition of all heavy atoms for residues A1-L51, including those of structurally undefined external side chains, afforded an average pairwise rms deviation of 0.72 +/- 0.08 A. Qualitative comparison of back-calculated and experimental two-dimensional NOESY spectra indicate that the DG/SA structures are consistent with the experimental spectra. The global folding of P. furiosus Zn(Rd) is remarkably similar to the folding observed by X-ray crystallography for native Rd from the mesophilic organism C. pasteurianum, with the average rms deviation value for backbone atoms of residues A1-L51 of P. furiosus Zn(Rd) superposed with respect to residues K2-V52 of C. pasteurianum Rd of 0.77 +/- 0.06 A. The conformations of aromatic residues that compose the hydrophobic cores of the two proteins are also similar. However, P. furiosus Rd contains several unique structural elements, including at least four additional hydrogen bonds and three potential electrostatic interactions.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- P R Blake
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County 21228
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250
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Park SH, Song HH, Park JM, Song KS, Sohn HS, Lee HJ, Kim BS, Kim HS, Kim YJ, Park JB. Impact of a primary reader's opinion on the detection of rib fractures. Invest Radiol 1992; 27:785-9. [PMID: 1399433 DOI: 10.1097/00004424-199210000-00007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
RATIONALE AND OBJECTIVES The authors assessed the influence of a prior reader's opinion on the detectability of rib fractures. METHODS Six pairs of observers read the chest PA radiographs of 92 subjects with rib fracture(s) and 28 normal subjects to detect rib fracture(s) according to a five-point rating of confidence with three methods. In method A, each reader read films as a primary reader. In method B, each reader read films after knowing his or her partner's opinion. In method C, each reader initially observed films and then made the final decision after knowing his or her partner's opinion. RESULTS Methods B and C were superior to method A in sensitivity. There was no difference in performance between methods B and C. Method C required a significantly longer time than the other methods. CONCLUSION Detection of rib fractures is improved by seeking the opinion of other observers.
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Affiliation(s)
- S H Park
- Department of Radiology, Catholic University Medical College, Seoul, Korea
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