Biomedical subjects
Publications and source records attributed to D K Lee.
Novel 1-(1-benzoylindoline-5-sulfonyl)-4-phenyl-4,5-dihydroimidazolon es 3 synthesized show highly potent and broad cytotoxicities. Among them compound 3b (DW2143) exhibits much more potent cytotoxicities than doxorubicin and highly effective antitumor activities against murine (3LL, Colon 26) and human xenograft (NCI-H23, SW620) tumor models.
The effect of dihydroguaiaretic acid (DHGA), isolated from the aryls of Myristica fragrans, on the transcription factor (fos-jun dimer) action was investigated via in vitro assay. DHGA showed an inhibitory effect against the complex formation of the fos-jun dimer and the DNA consensus sequence with an IC50 value of 0.21 micromol. Nordihydroguaiaretic acid (NDGA) and curcumin also inhibited fos-jun dimer action showing IC50 values of 7.9 and 6.9 nmol, respectively. DHGA and NDGA suppressed leukemia, lung cancer and colon cancer in an in vitro bioassay. The in vitro experiment suggested that inhibition of fos-jun-DNA complex formation could be due to the direct interference of fos-jun dimer binding onto the DNA consensus sequence by NDGA and curcumin.
Surfactin inhibits platelet and spleen cytosolic 100 kDa phospholipase A2 (PLA2). In contrast, this same compound enhances rat platelet group II PLA2 activity by approximately 2-fold and slightly increases group I PLA2 activity from porcine pancreas and Naja naja venom in vitro. Surfactin does not affect a Ca2+ -independent PLA2 partially purified from bovine brain. Thus, this compound inhibits selectively the cytosolic form of PLA2. Based on in vitro studies utilizing preincubation of surfactin with the enzyme, dialysis, and increased concentrations of substrates, the inhibitory effect of surfactin appears to be due to a direct interaction with the enzyme. Linear regression analysis of the linear portion of a concentration-response curve reveals an IC50 of 8.5 microM. To further determine the inhibitory pattern, a Dixon plot was constructed to show that the inhibition by surfactin is competitive, but not uncompetitive, with an inhibition constant of Ki = 4.7 microM in 50 mM Tris-HCl buffer, pH 8.0, at 37 degrees. Surfactin blocked non-stimulated and calcium ionophore A23187-stimulated release of arachidonic acid from monkey kidney CV-1 cells, which contain a cytosolic 100 kDa PLA2 as the major activity, as shown in an anionic exchange DEAE-5PW high performance liquid chromatography profile and western blotting analysis. Surfactin ameliorated inflammation induced by several chemicals. That is, it exhibited in vivo anti-inflammatory activity in several tested inflammatory reactions including 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear edema, carrageenan-induced rat paw edema, and acetic acid-induced mouse writhing. These results demonstrate that surfactin is a selective inhibitor for cytosolic PLA2 and a putative anti-inflammatory agent through the inhibitory effect produced by direct interaction with cytosolic PLA2, and that inhibition of cytosolic PLA2 activity may suppress inflammatory responses.
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.
We propose a simple one-dimensional RF pulse sequence for the study of chemical shift and heteronuclear dipolar coupling tensors of oriented as well as unoriented solids. An off-resonance RF decoupling of protons during the signal acquisition of less sensitive nuclei is used to suppress homonuclear 1H-1H dipolar interactions. This method is experimentally demonstrated on peptide samples selectively labeled with 15N isotope.
DW-116, (1-(5-fluoro-2-pyridyl)-6-fluoro-7-(4-methyl-1-piperazinyl)-1, 4-dihydro-4-oxoquinoline-3-carboxylic acid hydrochloride), is a new quinolone antibiotic with a broad antibacterial spectrum against G(+) and G(-) bacteria. DW-116 was evaluated for the immunomodulating activities, which is one of the efforts to investigate the mechanism of action related to the good in vivo antibacterial efficacy. The results of in vitro studies revealed there was no statistically significant increase in B and T lymphocyte proliferation. But the results of in vivo studies showed that the number of plaque forming cells (PFC), the amount of polyclonal antibodies and delayed-type hypersensitivity (DTH) were significantly increased after the repeat administration with 12 and 60 mg/kg of DW-116. Taken together, these results proposed that immunostimulating effect of DW-116 could be one of the action mechanisms for demonstrating in vivo antibacterial activities under these experimental conditions.
The safety, tolerability and pharmacokinetics of DW-116, a new fluoroquinolone with a broad antibacterial spectrum, were evaluated in healthy male subjects after administration of single oral doses of 100, 200, 300 and 800 mg and after administration of multiple oral doses of 300 or 400 mg, respectively, for 7 days. DW-116 was well tolerated. Gastrointestinal symptoms and skin reactions were noted and considered to be possibly related to DW-116. The geometric means of the maximum plasma concentrations (Cmax) linearly increased with the dose administered from 1.19 mg/L to 8.73 mg/L after single dose administration. At steady state, the geometric mean minimum and maximum plasma concentrations were 2.14 and 5.65 mg/L, respectively, after the multiple 300 mg dose and 2.73 and 8.00 mg/L, respectively, for the multiple 400 mg dose. Tmax varied between 1 and 5 h. The terminal half-life ranged from 11.37 to 24.89 h. The geometric mean renal clearance was approximately 30 mL/min. Approximately 45% of the dose was excreted unchanged in urine within 60 h. There was no clinically relevant deviation from dose proportionality. The changes in steady-state pharmacokinetic parameters when DW-116 was taken before a high-fat breakfast were not clinically relevant. In conclusion, DW-116 was safe in this study, the first administration to human subjects. Its pharmacokinetics indicate that once-daily dosing may be possible.
BACKGROUND: Studies to date suggest that venlafaxine is effective, well tolerated, and safe in a broad spectrum of patients. We examined the clinical utility and tolerability of venlafaxine in patients treated by community-based psychiatrists and family physicians in a naturalistic clinical setting. METHOD: Nineteen physicians each recruited 10 to 20 physicians to enroll 5 patients each maximum, diagnosed with DSM-IV major depression or dysthymia. The patients were at least moderately ill (Clinical Global Impressions) with a score of at least 32 on the Zung Self-Rating Depression Scale. After baseline clinical and laboratory assessments, each patient received 37.5 mg of venlafaxine b.i.d., with adjustments possible at the 5 visits during the next 8 weeks. RESULTS: Of the 880 patients at baseline, 682 completed the 8-week study. The daily doses of venlafaxine ranged between 18.75 mg and 375 mg, with 80% receiving between 75 and 150 mg/day by 8 weeks. The intent-to-treat analysis revealed that at 8 weeks, 62% (522 of 843) of patients were either much or very much improved. Nausea was the most frequent side effect, followed by somnolence, headache, and dry mouth. CONCLUSION: Venlafaxine has good clinical utility and tolerability in a community-based sample of a broad spectrum of depressed outpatients.
166Holmium (166Ho) is a radionuclide of rare earth chemical and is known to have antitumor activity. Several chemicals were complexed with 166Ho to facilitate the transport of this radionuclide to the site of action. In this study, 166Ho was complexed to chitosan (Chit) which decreases the distribution of Ho into other tissues when applied intrahepatically. To investigate the single dose toxicity, mice were administered intravenously with 1 mCi/kg body weight of 166Ho-Chit (DW-166HC), Chit or nothing. Organ weights, hematological and histopathological studies were performed in 6 animals per group at 1, 3 and 14 days after administration. In 166Ho-Chit treated animals, a slight decrease of erythrocyte number was observed at day 14 and increases of relative liver and lung weights were found at day 3. Although marked multiple necrotic foci in the white pulp and depletion of marginal zone in the spleen were noted at day 1, these findings were decreased in severity and fully recovered at day 3 and day 14, respectively. Slightly decreased kidney weights were observed both in Chit and in 166Ho-Chit treated groups without histological alterations. Thus it is suggested that most effects of 166Ho-Chit observed at an early stage after administration are limited to rapidly dividing cells and reversible within 14 days.
An ecological study has been performed on the community structures of aquatic animals and on abiotic factors in organically and conventionally-farmed rice fields at Bulkyo, Bosong-gun, Chollanamdo during the rice growing periods between May 1995 and October 1996. The total numbers of aquatic insect taxa in these fields were 25 species, 22 families in 10 orders. In 1995 and 1996, three and then four more species of aquatic insects were collected in the organically-farmed rice fields than in conventionally-farmed rice fields. The common dominant species in both rice fields during the rice cultivation period was Chironomus sp. The abundance of two vector mosquitoes, Anopheles sinensis and Culex tritaeniorhynchus, was lower in the organically-farmed rice fields as compared to the conventionally-farmed rice fields. The populations of mosquito larvae in the organically-farmed rice fields might have been influenced by Chinese muddy loaches, Misgurnus mizolepis. Coefficients of correlation between Chinese muddy loaches and abundance of mosquito larvae showed negative correlations in An. sinensis (-0.66) and Cx. tritaeniorhynchus (-0.47). The average of the species diversity index for organically-farmed rice fields was almost twice (0.62) as much as is of conventionally-farmed rice fields (0.35). The average community similarity between both types of fields was very low (0.33).
Although the beta-adrenergic antagonist propranolol (1) binds at rodent 5-HT1B serotonin receptors, it displays low affinity (Ki > 10,000 nM) for its species homologue 5-HT1D beta (i.e., h5-HT1B) receptors. The structure of propranolol was systematically modified in an attempt to enhance its affinity for the latter population of receptors. Removal of the alkyl hydroxyl group, shortening of the O-alkyl chain from three to two methylene groups, and variation of the terminal amine substituent resulted in compounds, such as N-monomethyl-2-(1-naphthyloxy)-ethylamine (11; Ki = 26 nM), that display significantly higher h5-HT1B affinity than propranolol. Compound 11 was shown to bind equally well at human 5-HT1D alpha (h5-HT1D) receptors (Ki = 34 nM) and was further demonstrated to possess h5-HT1B agonist character in an adenylate cyclase assay. It would appear that such (aryloxy)alkylamines may represent a novel class of 5-HT1D receptor agonists.
The binding of TFIID to the TATA element initiates assembly of a preinitiation complex and thus represents one of the most important steps for transcriptional regulation. The fact that the TATA binding protein (TBP), a subunit of TFIID, exclusively contacts the minor groove of the TATA element led us to ask whether the major groove of the TATA element plays any role in transcription initiation or its regulation. Our results show that modifications of the major groove of the TATA element in the adenovirus major late promoter have no effect on TFIID binding affinity or on transcription in a cell-free system reconstituted with purified factors. However, major groove modifications do decrease the levels of both basal and activator-mediated transcription in unfractionated nuclear extracts, indicating that the intact structure of the major groove of the TATA element is functionally important for transcription initiation in a more physiological context.
Both the TATA and CCAAT boxes are widespread promoter elements and their binding proteins, TBP and NF-Y, are extremely conserved in evolution. NF-Y is composed of three subunits, NF-YA, NF-YB and NF-YC, all necessary for DNA binding. NF-YB and NF-YC contain a putative histone-like motif, a domain also present in TBP-associated factors (TAFIIs) and in the subunits of the transcriptional repressor NC2. Immunopurification of holo-TFIID with anti-TBP and anti-TAFII100 antibodies indicates that a fraction of NF-YB associates with TFIID in the absence of NF-YA. Sedimentation velocity centrifugation experiments confirm that two pools of NF-YB, and most likely NF-YC, exist: one associated with NF-YA and binding to the CCAAT box; another involved in high molecular weight complexes. We started to dissect NF-Y-TFIID interactions by showing that: (i) NF-YB and NF-YC interact with TBP in solution, both separately and once bound to each other; (ii) short stretches of both NF-YB and NF-YC located within the evolutionary conserved domains, adjacent to the putative histone fold motifs, are necessary for TBP binding; (iii) TBP single amino acid mutants in the HS2 helix, previously shown to be defective in NC2 binding, are also unable to bind NF-YB and NF-YC.
The heavy metal mercury elicits a genetically restricted, anti-nucleolar autoantibody response that targets fibrillarin, a 34-kDa protein component of many small nucleolar ribonucleoprotein particles. The mechanisms by which a toxin such as mercury elicits an autoantibody response that predominantly targets a single intracellular protein autoantigen remain uncertain, but may be prefaced by mercury gaining access to the intracellular environment. Mercury-induced cell death was associated with loss of fibrillarin antigenicity and modification of the molecular properties of fibrillarin as revealed by aberrant migration under nonreducing conditions in SDS-PAGE. Addition of mercury to isolated nuclei also resulted in aberrant migration of fibrillarin, but not other nuclear autoantigens. The sensitivity of the HgCl2-induced modification of fibrillarin to 2-ME, iodoacetamide, and hydrogen peroxide suggested interaction of mercury with the two cysteines in the fibrillarin sequence. This was confirmed by mutation of the cysteines to alanines, which abolished the aberrant migration of fibrillarin in the presence of HgCl2. The modification of the molecular structure of fibrillarin by mercury reduced immunoprecipitation by anti-fibrillarin autoantibodies, pointing to unmodified fibrillarin as the B cell Ag and implicating mercury-modified fibrillarin as the source of T cell antigenicity. These observations demonstrate for the first time that an environmental toxin can alter the physicochemical properties of an autoantigen and may help to explain the antigenic specificity of mercury-induced murine autoimmunity.
It is well known that attention increases the discriminability of some types of spatial information. To ascertain more specifically which types of spatial information benefit from attention, we have measured spatial vision thresholds both in the presence and in the near absence of attention. To obtain near absence of attention, we induce subjects to focus attention elsewhere in the display by means of a suitably demanding concurrent visual task. We measure contrast and orientation thresholds for sine-wave gratings, as well uni- and bidirectional offset thresholds for vernier targets. The results suggest that attention selectively lowers some thresholds but not others: orientation thresholds are far more affected than contrast thresholds, and bidirectional vernier thresholds are far more affected than unidirectional thresholds.
DW-116 is a novel fluoroquinolone that was two- to four-fold more active than rufloxacin and less active than sparfloxacin, ciprofloxacin and ofloxacin against Gram-positive bacteria in vitro. Against Gram-positive and Gram-negative bacteria, the in-vivo activity of DW-116 was similar or slightly greater than that of rufloxacin and less than that of sparfloxacin, ciprofloxacin and ofloxacin. ED50 (50% effective dose) values for DW-116 did not correlate with in-vitro MICs.
One hundred and twenty women undergoing gynaecological abdominal operations were randomized to receive either epidural bupivacaine 0.0625% + fentanyl 3.3 micrograms/ml infusion (Group EPI, n = 57), or patient-controlled intravenous morphine analgesia (Group PCA, n = 54) for postoperative pain relief. The groups were comparable in demographic data, types and duration of operation. Group EPI achieved significantly lower verbal rating scale of pain (VRS) at rest at 0, 4, 12, 16, 20, 28 and 40th postoperative hours. The VRS during cough were also significantly lower in Group EPI at 0, 4, 8, 12, 28 and 36th postoperative hours. None of the patients had respiratory depression or hypotension. Nausea/vomiting occurred in 52.6%/33.3% of patients in Group EPI and 52.7%/37.0% in Group PCA. Most patients (84.2% in Group EPI and 72.2% in Group PCA) rated their pain management as "good". We conclude that epidural infusion of bupivacaine 0.0625% and fentanyl 3.3 micrograms/ml provide better analgesia than patient-controlled intravenous morphine after gynaecological laparotomy.
We reported a 43-year-old woman who showed a Guillain-Barré like syndrome associated with acute renal failure (ARF) and thrombocytopenia following acute viral hepatitis A(HA). The clinical feature was acute progressive and of ascending symmetric paraparesis which developed 5 days after gastrointestinal infection. Neurologic examination showed flaccid paraparesis, areflexia in all extremities and limitation on the straight leg raising test. Laboratory examinations showed the evidences of ARF, thrombocytopenia and HA. EMG findings suggested a polyradiculopathy. Renal biopsy showed the findings of acute interstitial nephritis, acute tubular necrosis and IgA deposition nephropathy. She was treated by plasmapheresis and platelet transfusion, then showed a rapid improvement, and has been well without further complication after discharge.