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J K Kim

Publications and source records attributed to J K Kim.

At least 163 records · Page 9Linked to original sources
PubMed1998

Triprimer-PCR method: rapid and reliable detection of transgenes in transgenic rice plants.

We designed a triprimer-PCR system for detection of transgenes and applied for analysis of two different kinds of transgenic rice plants, which were previously transformed with the plasmids pBY605RR or pARP7 containing a maize ribosome-inactivating protein gene, Zmcrip3a, and a herbicide-resistant gene, bar. Genomic Southern-blot analysis demonstrated that the transgenes were stably inherited to their R1 progenies without changes in configuration. The resulting data were used as a reference for triprimer-PCR analysis. The triprimer-PCR system uses an endogenous gene as an internal standard which shares an identical priming site for one primer with a transgene while each of the other two primers is specific to either the transgene or the endogenous gene. Triprimer-PCR analysis was carried out on genomic DNA isolated from 24 different progenies of the pBY605RR- and the pARP7-transformed lines that contain different copy numbers of transgenes. The RbcS:Zmcrip3a junction region of the pBY605RR integrated in rice chromosomes, together with the endogenous RbcS, was efficiently amplified, producing 440 and 250 bp expected PCR products. Also, the Act1:Zmcrip3a junction region of the transgene pARP7 with the endogenous Act1 was similarly amplified, producing 540 and 340 bp expected PCR products. The two PCR products in each set of experiments were observed consistently and independently of copy numbers or rearrangements of the transgene. Thus, the triprimer-PCR strategy may provide a rapid and reliable method for confirming transformation or analyzing segregation of transgenes at the molecular level.

Blotting, Southern↗
PubMed1998

Control of initiation of viral plus strand DNA synthesis by HIV reverse transcriptase.

Human immunodeficiency virus reverse transcribes its single-stranded RNA genome making a DNA copy. As synthesis proceeds, the RNA is simultaneously degraded to oligomers; one of these, the polypurine tract, primes synthesis of a plus strand DNA. The viral reverse transcriptase (RT) degrades all of the non-polypurine tract oligomers. We show that unlike other DNA polymerases the retroviral RT can bind either end of an annealed RNA primer, the 5'-end for degradation and the 3'-end for synthesis. The competition between the two binding modes at any primer determines whether it will be extended or degraded. The 5'-end binding can be suppressed in at least two ways. The sequence of the primer can be such that a region at the 5'-end is unannealed or a DNA primer can be annealed just adjacent to the 5'-end of the RNA primer. This promotes binding of RT to the RNA 3'-end, allowing a primer that would normally be degraded to be extended. Implications for human immunodeficiency virus replication and antiviral therapy are discussed.

Binding Sites↗
PubMed1998

Involvement of hydrogen peroxide in the differentiation of clonal HD-11EM cells into osteoclast-like cells.

The present study uses the osteoclast precursor clonal line, HD-11EM, to study the potential of hydrogen peroxide (H2O2) in mediating the differentiation of HD-11EM into osteoclast-like cells. HD-11EM cells are a newly established clonal cell line that, in response to 1alpha,25-(OH)2D3, differentiate into osteoclast-like cells that are multinucleated (more than three nuclei), express tartrate-resistant acid phosphatase (TRAP), and excavate resorption pits when cultured on dentin slices in the presence of osteoblasts (Hsia et al., 1995, J. Bone Miner. Res., 10(Suppl 1):S424; Hsia, and Hauschka, 1997, unpublished data). Here we demonstrate that HD-11EM express the reduced nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase specific cytochrome b558 subunits, and that stimulation of HD-11EM with 1 or 10 nM 1alpha,25-(OH)2D3 increases the extracellular release of H2O2 within 5-10 min. Ours is the first report that stimulation of a cell with 1alpha,25-(OH)2D3 enhances the activation of NADPH-oxidase and increases the basal release of superoxide and the formation of its dismutation product, H2O2. To determine the possible involvement of H2O2 in the differentiation of HD-11EM, these cells were exposed to glucose/glucose oxidase. This enzyme system was used to deliver a pure and continuous source of H2O2 in nanomole amounts consistent with quantities produced by HD-11EM in response to 1alpha,25-(OH)2D3. Both 1alpha,25-(OH)2D3 and the exogenously generated H2O2 stimulated a dose- and time-dependent increase in TRAP activity/cell and the number of multinucleated cells 24-48 hr after treatment. Northern analysis confirmed an increase in expression of TRAP mRNA in response to either 1alpha,25-(OH)2D3 or H2O2. Decreases in cell proliferation and v-myc mRNA were also observed in response to these agents. Taken together, our findings indicate that production of H2O2 by HD-11EM is an important local factor involved in differentiation of HD-11EM into osteoclast-like cells, and suggest that H2O2 may play a role in native osteoclast differentiation.

Acid Phosphatase↗
PubMed1998

Changes in brain-derived neurotrophic factor immunoreactivity in rat dorsal root ganglia, spinal cord, and gracile nuclei following cut or crush injuries.

In the present study, we evaluated changes in brain-derived neurotrophic factor (BDNF) immunoreactivity in the rat lumbar (L) 5 dorsal root ganglion (DRG) and areas where afferents from the DRG terminate, the L5 spinal cord and gracile nuclei, following unilateral sciatic nerve transection or crush. From 3 days to 4 weeks following cut or crush injury, the percentage of medium and large BDNF-immunoreactive neurons in the ipsilateral DRG increased significantly compared with those on the contralateral side. Following cut injury, there was no significant change in the percentage of small BDNF-immunoreactive neurons in the ipsilateral DRG; however, the intensity of immunoreactivity of these cells decreased. Following crush injury, however, both the percentage and intensity of small BDNF-immunoreactive neurons in the ipsilateral DRG significantly increased. Following cut injury, the expression of BDNF-immunoreactive axonal fibers decreased markedly in the ipsilateral superficial laminae of the L5 spinal cord and increased significantly in the ipsilateral deeper laminae of the spinal cord and gracile nuclei. Crush injury induced a marked increase in the expression of BDNF-immunoreactive axonal fibers in the superficial laminae of the spinal cord and gracile nuclei. These differences in BDNF response in the DRG and spinal cord after cut or crush injuries may reflect differences in trophic support to the injured DRG neurons and altered neuronal activity in the spinal cord and gracile nuclei following different types of peripheral nerve injury.

Animals↗
PubMed1998

Antitumor activity of the aqueous-alcoholic extracts from unripe cotton ball of Gossypium indicum.

The present study investigated the antitumor activity of the aqueous-alcoholic extracts from unripe cotton balls of Gossypium indicum. An Exposure of murine B16 melanoma and L1210 lymphoma cells to the extracts resulted in their severe deaths in time- and concentration-dependent manners. Of the extracts, hydrophilic fractions were most efficacious for the antitumor activity and found to contain certain amounts of catechin and its derivatives. The hydrophilic extract fraction C36B2-8 had approximately 10 times more cytotoxic effects on B12 and L1210 cells than on isolated murine thymocytes. High concentrations (> 150 micrograms/ml) of C 36B3-8 mainly induced necrotic cell death. At low concentrations (< 100 micrograms/ml), however, C 36B3-8 induced not only necrosis but also apoptosis of the two tumor cell lines, which was proved by the TUNEL staining and DNA fragmentation techniques. The data indicate that certain ingredients of the cotton ball extract of G. indicum have an antitumor activity.

Animals↗
PubMed1998

Antitumor activity of 7-[2-(N-isopropylamino)ethyl]-(20S)-camptothecin, CKD602, as a potent DNA topoisomerase I inhibitor.

We developed a novel water-soluble camptothecin analogue, CKD602, and evaluated the inhibition of topoisomerase I and the antitumor activities against mammalian tumor cells and human tumor xenografts. CKD602 was a nanomolar inhibitor of the topoisomerase I enzyme in the cleavable complex assay. CKD602 was found to be 3 times and slightly more potent than topotecan and camptothecin as inhibitors of topoisomerase, respectively. In tumor cell cytotoxicity, CKD602 was more potent than topotecan in 14 out of 26 human cancer cell lines tested, while it was comparable to camptothecin. CKD602 was tested for the in vivo antitumor activity against the human tumor xenograft models. CKD602 was able to induce regression of established HT-29, WIDR and CX-1 colon tumors, LX-1 lung tumor, MX-1 breast tumor and SKOV-3 ovarian tumor as much as 80, 94, 76, 67, 87% and 88%, respectively, with comparable body weight changes to those of topotecan. Also the therapeutic margin (R/Emax: maximum tolerance dose/ED58) of CKD602 was significantly higher than that of topotecan by 4 times. Efficacy was determined at the maximal tolerated dose levels using schedule dependent i.p. administration in mice bearing L1210 leukemia. On a Q4dx4 (every 4 day for 4 doses) schedule, the maximum tolerated dose (MTD) was 25 mg/kg per administration, which caused great weight loss and lethality in < 5% tumor bearing mouse. This schedule brought significant increase in life span (ILS), 212%, with 33% of long-term survivals. The ex vivo antitumor activity of CKD602 was compared with that of topotecan and the mean antitumor index (ATI) values recorded for CKD602 were significantly higher than that noted for topotecan. From these results, CKD602 warrants further clinical investigations as a potent inhibitor of topoisomerase I.

Animals↗
PubMed1998

Reduction of radiation-induced chromosome aberration and apoptosis by dithiothreitol.

We have examined in vitro and in vivo radioprotective effects of a well-known thiol-containing compound, dithiothreitol (DTT). The treatment of both 0.5 and 1 mM of DTT significantly increased clonogenic survival of gamma-ray irradiated Chinese hamster (V79-4) cells. In order to investigate the possible radioprotective mechanism of DTT, we measured gamma-ray induced chromosome aberration by micronucleus assay. In the presence of 0.5 mM or 1 mM DTT, the frequencies of micronuclei were greatly reduced in all dose range examined (1.5-8 Gy). Slightly higher reduction in micronucleus formation was observed in 1 mM DTT-treated cells than in 0.5 mM DTT-treated cells. In addition, incubation with both 0.5 and 1 mM of DTT prior to gamma-ray irradiation reduced nucleosomal DNA fragmentation at about same extent, this result suggests that treatment of DTT at concentrations of 0.5 and 1 mM reduced radiation-induced apoptosis. In vivo experiments, we also observed that DTT treatment reduced the incidence of apoptotic cells in mouse small intestine crypts. In irradiated control group 4.4 +/- 0.5 apoptotic cells per crypt were observed. In DTT-administered and irradiated mice, only 2.1 +/- 0.4 apoptotic cells per crypt was observed. In vitro and in vivo data obtained in this study showed that DTT reduced radiation-induced damages and it seems that the possible radioprotective mechanisms of action of DTT are prevention of chromosome aberration.

Animals↗
PubMed1998

Molecular and genetic characterization of two anti-DNA antibodies derived from patients with systemic lupus erythematosus.

Anti-double stranded(ds) DNA antibody is one of markers of systemic lupus erythematosus (SLE). Two human monoclonal anti-DNA antibody-producing cell lines were established from two SLE patients. One cell line secreted IgG isotype antibody (KSUG) and the other secreted IgM isotype antibody (KSUN). The light chains of the two immunoglobulins were lambda chains. The nucleotide sequences for the immunoglobulin variable region genes of the two antibodies were determined and compared to germline sequences. The heavy and lambda light chains of KSUG were VH3 family and V lambda IIIb, respectively. The heavy and lambda light chains of KSUN were VH4 family and V lambda IX, respectively. Antibody KSUG, IgG isotype, showed somatic mutations, whereas KSUN, IgM isotype, used the germline gene without mutation. These findings reconfirm the current paradigms that IgM anti-DNA antibodies are produced by utilizing germline genes whereas IgG anti-DNA antibodies are produced by somatic mutations.

Adult↗
PubMed1998

In vivo differential diagnosis of prostate cancer and benign prostatic hyperplasia: localized proton magnetic resonance spectroscopy using external-body surface coil.

Localized proton-stimulated echo acquisition mode (STEAM) spectroscopy was performed in seven patients with benign prostatic hyperplasia (BPH), six patients with prostate cancer, and seven healthy volunteers to determine whether citrate levels detected using a saddle-type external-body surface coil (two loops of 13 cm x 17 cm) could reliably discriminate BPH from prostatic cancer. Relative area ratios of citrate level to choline plus creatine or citrate to lipid signal were compared with postoperative pathologic histology findings. The metabolic signals were well detectable as much as the line width of water resonance was ranging from 5 to 9 hz. Average SNRs of citrate in BPH and prostate cancer were 11.4 and 1.9, respectively. The major finding was consistently lower citrate levels in prostate cancer compared with BPH and normal prostate central gland. This was significantly (p < 0.01) reflected by lower mean citrate/[creatine+choline] peak area ratio and citrate/lipid peak area ratio observed for region of cancer (0.446 +/- 0.063, 0.097 +/- 0.030) compared with BPH (1.458 +/- 0.107, 0.786 +/- 0.162) and normal central gland (1.418 +/- 0.129, 0.175 +/- 0.011), respectively. These studies demonstrate the potential of citrate spectrum detected by an external-body surface coil as an in vivo marker for discriminating prostate cancer from BPH.

Adult↗
PubMed1998

Systemic hemodynamic, neurohormonal, and renal effects of a steady-state infusion of human brain natriuretic peptide in patients with hemodynamically decompensated heart failure.

BACKGROUND: Human brain natriuretic peptide (hBNP) is a promising agent for the treatment of decompensated cardiac failure. However, the systemic hemodynamic, neurohormonal, and renal effects of hBNP have been incompletely studied in human heart failure. METHODS AND RESULTS: The effects of a continuous 4-hour infusion of hBNP were determined in 16 decompensated heart failure patients in an invasive, randomized, double-blind, placebo-controlled study. Patients were evaluated during three 4-hour study periods: baseline, treatment (placebo [n = 4] versus hBNP 0.025 or 0.05 microgram/kg/min [n = 12]), and post-treatment. Urinary volume losses were replaced hourly to separate the vasodilatory and diuretic effects of hBNP. Two patients in the hBNP group were excluded from the analysis because of adverse events. hBNP significantly (P < .001) reduced right atrial pressure and pulmonary capillary wedge pressure by approximately 30% and 40%, respectively. hBNP also significantly lowered systemic vascular resistance from 1722 +/- 139 to 1101 +/- 83 dynes.s.cm-5 (P < .05). These unloading effects of hBNP produced a 28% increase in cardiac index (P < .05) with no change in heart rate. Compared to placebo, hBNP decreased plasma norepinephrine and aldosterone. Renal hemodynamics were unaffected by hBNP; however, most patients were resistant to its natriuretic effect. CONCLUSIONS: 1) The predominant hemodynamic effects of hBNP were a decrease in cardiac preload and systemic vascular resistance. 2) hBNP also improved cardiac output without increasing heart rate. 3) Plasma norepinephrine and aldosterone levels decreased during hBNP infusion. 4) hBNP is pharmacologically active and has potential in the therapy for decompensated heart failure.

Adult↗
PubMed1998

Expression of Tcf-1 mRNA and surface TCR-CD3 complexes are reduced during apoptosis of T cells.

When a T cell hybridoma, 70.7, was treated with a Ca2+ ionophore (A23187), apoptotic cell death was induced. Interestingly, we observed that the expression of Tcf-1, a T cell-specific transcription factor, mRNA was reduced by approximately 5-fold in the A23187-treated apoptotic cells compared to an ethanol-treated control. The hybridoma cells, however, did not display such a reduced expression of Tcf-1 mRNA upon treatment with buthionine sulfoxide, which is known to induce a necrosis-like cell death. When another T cell hybridoma, KMIs-8.3.5, was treated with A23187 and phorbol myristate acetate, which leads to activation-induced apoptosis, Tcf-1 expression was again greatly reduced. However, a mutant line (KCIT1-8.5) derived from KMIs-8.3.5, which produces IL-2 upon activation and is resistant to apoptosis, did not show such reduction in Tcf-1 expression. We also showed that the reduced expression level of CD3epsilon mRNA and surface TCR-CD3 complex in apoptotic T cells is caused by the reduced expression of Tcf-1. When 70.7 cells were transfected with a plasmid DNA pSVtcf-1, in which Tcf-1 gene expression is driven by the SV40 promoter, such reduction of the Tcf-1 mRNA and the surface expression of the TCR-CD3 complex were not observed upon apoptosis induction. Our results suggest that the reduced expression of Tcf-1 is specific for the apoptotic, but not for the activating, process of T cells and is also responsible for the reduced surface expression of the TCR-CD3 in apoptotic T cells.

Animals↗
PubMed1998

Test bolus examination in the carotid artery at dynamic gadolinium-enhanced MR angiography.

At magnetic resonance angiography in nine patients, a test bolus of gadopentetate dimeglumine was injected to determine transit time from venous injection to arrival in the carotid arteries. Mean times to onset of enhancement were calculated (arterial, 15.7 seconds [range, 10-22 seconds]; venous, 23.4 seconds [range, 16-30 seconds]; optimal imaging time, 7.78 seconds [range, 6-10 seconds]). Transit time was calculated correctly with a test bolus examination.

Aged↗
PubMed1998

Reduced glucose clearance as the major determinant of postabsorptive hyperglycemia in diabetic rats.

The relationships between postabsorptive glucose concentration and hepatic glucose output (HGO) and glucose clearance were studied in rats one day after treatment with various doses of streptozotocin (STZ; 0, 15, 30, 40, 50, or 75 mg/kg; n = 6 per dose; study 1). Glucose fluxes were estimated using a prolonged (6-h) infusion of [3-3H]glucose to ensure complete tracer equilibration at hyperglycemia. Postabsorptive glucose was significantly increased at the high doses of STZ (50 and 75 mg/kg; P < 0.01) and was strongly correlated with glucose clearance across all doses (r = -0.85, P < 0.001) but less strongly with HGO (r = 0.46, P < 0.01). In the group treated with 50 mg/kg STZ, postabsorptive glucose was increased twofold compared with the control (i.e., zero dose) group, with no change in HGO and a 45% decrease in glucose clearance, indicating that the hyperglycemia was due to a decrease in glucose clearance. To understand the cellular mechanisms of decreased glucose clearance in STZ diabetic rats, skeletal muscle glucose clearance and intracellular glucose and glucose 6-phosphate (G-6-P) concentrations were determined in normal and STZ (50 mg/kg) diabetic rats at their postabsorptive glucose levels as well as at matched hyperglycemia (12 mM; study 2). Glucose clearance was significantly decreased in soleus (P < 0.05) muscles of the diabetic rats, and this was associated with significantly decreased intracellular glucose and G-6-P levels at matched hyperglycemia (P < 0.05), suggestive of decreased glucose transport. In conclusion, postabsorptive hyperglycemia in STZ diabetic rats was largely due to decreased glucose clearance, although increased HGO may also have been a contributing factor at the highest STZ dose. The decrease in postabsorptive glucose clearance in STZ diabetic rats appeared to be associated with an impairment of glucose transport in soleus (type I) muscles.

Animals↗
PubMed1998

Kimura's disease: two case reports and a literature review.

Kimura's disease (KD) is an allergic, inflammatory disorder of unknown cause. The typical presentation is in a young Oriental male with nontender subcutaneous swellings in the head and neck region, lymphadenopathy, peripheral eosinophilia, and elevated serum IgE. Many patients with KD also develop renal involvement. Treatment options range from conservative observation for asymptomatic patients to surgical excision, steroid therapy, and radiotherapy for symptomatic patients. Two cases of KD are presented. These emphasize not only the variability of disease presentation, but also the pitfalls of therapy leading to frequent recurrences. The literature is reviewed, summarizing patient presentation, differential diagnosis, current theories on causation, and therapy. A treatment protocol is also proposed.

Adolescent↗
PubMed1998

Scoliosis in elderly and age-related bone loss: a population-based study.

Osteoporosis, a common metabolic condition resulting in reduced bone mass, causes significant morbidity in affected individuals by predisposing them to osteoporotic fractures. To determine the relationship of scoliosis and osteoporosis, dual-energy X-ray absorptiometry (DXA) scans of 493 men and 762 women were analyzed according to their scoliotic status. No association was observed in the few scoliotic men without osteoarthritis of the spine compared to nonscoliotic men. Without osteoarthritis, scoliotic women had significantly decreased bone mass of the total hip and the femoral neck (p < 0.05) compared to nonscoliotic women, whereas in spine, bone mass was also decreased compared to nonscoliotic women, but not statistically significant. This suggests that scoliosis associates with bone loss, and affected women may benefit from early institution of therapeutic measures.

Journal Article↗
PubMed1998

Localized in vivo proton spectroscopy of renal cell carcinoma in human kidney.

In order to obtain proton magnetic resonance spectra from the renal tumor in human kidney we performed localized magnetic resonance spectroscopy using a saddle-type flexible surface coil. Five patients biopsy-proven as renal cell carcinoma at different stages were put in supine/lateral position to minimize motion artifacts while acquiring the spectrum. Water-suppressed 1H spectra were obtained with localized stimulated echo acquisition mode (STEAM) (20/13.7/2200; TE/TM/TR) and point resolved spectroscopy (PRESS) (288/2200; TE/TR) sequences. The principal resonances in the tumor STEAM spectrum were sorbitol (3.85 ppm), trimethylamines (TMA) (3.25 ppm), two unidentified signals (2.8 and 2.2 ppm), and lipid (0.9-1.8 ppm). In the PRESS spectrum using a long echo time (288 ms), two well localized signals, TMA at 3.25 ppm and lactate at 1.35 ppm were observed from a patient with a tumor at advanced stage. Interestingly only TMA at 3.25 ppm was observed from the patient with a low grade tumor. The spectral patterns of the tumor patients were different from those of normal kidney.

Adult↗
PubMed1998

Vasculature in hepatocellular carcinoma after transcatheter arterial chemoembolization: comparison of power and color Doppler sonography.

The purpose of this study was to compare power Doppler sonography with conventional color Doppler sonography for the detection of the vascularity of hepatocellular carcinomas after transcatheter arterial chemoembolization. Of the 93 embolized hepatocellular carcinomas, hypervascularity was demonstrated in 36 on angiography; power Doppler sonography correctly identified pulsatile flow signals in 33 (92%) of these 36, whereas color Doppler sonography identified flow signals in 24 (67%). A statistically significant difference was noted when the sizes of the nodules were 30 mm or less. Despite technical difficulties, such as flash artifact, power Doppler sonography is superior to color Doppler sonography for detection of hypervascularity, especially in small embolized nodules of hepatocellular carcinoma (30 mm or less in diameter).

Adult↗