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Biomedical subjects

C Kim

Publications and source records attributed to C Kim.

At least 145 records · Page 8Linked to original sources
PubMed2000

T-DNA insertional mutagenesis for functional genomics in rice.

We have produced 22 090 primary transgenic rice plants that carry a T-DNA insertion, which has resulted in 18 358 fertile lines. Genomic DNA gel-blot and PCR analyses have shown that approximately 65% of the population contains more than one copy of the inserted T-DNA. Hygromycin resistance tests revealed that transgenic plants contain an average of 1.4 loci of T-DNA inserts. Therefore, it can be estimated that approximately 25 700 taggings have been generated. The binary vector used in the insertion contained the promoterless beta-glucuronidase (GUS) reporter gene with an intron and multiple splicing donors and acceptors immediately next to the right border. Therefore, this gene trap vector is able to detect a gene fusion between GUS and an endogenous gene, which is tagged by T-DNA. Histochemical GUS assays were carried out in the leaves and roots from 5353 lines, mature flowers from 7026 lines, and developing seeds from 1948 lines. The data revealed that 1.6-2.1% of tested organs were GUS-positive in the tested organs, and that their GUS expression patterns were organ- or tissue-specific or ubiquitous in all parts of the plant. The large population of T-DNA-tagged lines will be useful for identifying insertional mutants in various genes and for discovering new genes in rice.

Base Sequence↗
PubMed2000

Transsphenoidal supradiaphragmatic intradural approach: technical note.

Presellar extension of the bone window combined with removal of the sellar floor results in the transsphenoidal supradiaphragmatic intradural approach. One tuberculum sella meningioma and another suprasellar Rathke's cleft cyst confined to the pituitary stalk were removed via this approach. The presellar extension of the bone window was performed with the sublabial transseptal transsphenoidal technique. Furthermore, the dissection of the anterior intercavernous sinus, diaphragma sella, and arachnoid trabecula has allowed a wide surgical field of pre- and suprasellar areas and facilitates safe removal of lesions without significant surgical complications in selected cases.

Adult↗
PubMed2000

Tissue-preferential expression of a rice alpha-tubulin gene, OsTubA1, mediated by the first intron.

The genomic clone encoding an alpha-tubulin, OsTubA1, has been isolated from rice (Oryza sativa L.). The gene consists of four exons and three introns. RNA-blot analysis showed that the gene is strongly expressed in actively dividing tissues, including root tips, young leaves, and young flowers. Analysis of chimeric fusions between OsTubA1 and beta-glucuronidase (GUS) revealed that the intron 1 was required for high-level GUS expression in actively dividing tissues, corresponding with normal expression pattern of OsTubA1. Fusion constructs lacking the intron 1 showed more GUS staining in mature tissues rather than young tissues. When the intron 1 was placed at the distal region from 5'-upstream region or at the 3'-untranslated region, no enhancement of GUS expression was observed. Sequential deletions of the OsTubA1 intron 1 brought about a gradual reduction of GUS activity in calli. These results suggest that tissue-preferential expression of the OsTubA1 gene is mediated by the intron 1 and that it may be involved in a mechanism for an efficient RNA splicing that is position dependent.

Blotting, Northern↗
PubMed2000

leafy hull sterile1 is a homeotic mutation in a rice MADS box gene affecting rice flower development.

Rice contains several MADS box genes. It has been demonstrated previously that one of these genes, OsMADS1 (for Oryza sativa MADS box gene1), is expressed preferentially in flowers and causes early flowering when ectopically expressed in tobacco plants. In this study, we demonstrated that ectopic expression of OsMADS1 in rice also results in early flowering. To further investigate the role of OsMADS1 during rice flower development, we generated transgenic rice plants expressing altered OsMADS1 genes that contain missense mutations in the MADS domain. There was no visible alteration in the transgenic plants during the vegetative stage. However, transgenic panicles typically exhibited phenotypic alterations, including spikelets consisting of elongated leafy paleae and lemmas that exhibit a feature of open hull, two pairs of leafy palea-like and lemma-like lodicules, a decrease in stamen number, and an increase in the number of carpels. In addition, some spikelets generated an additional floret from the same rachilla. These characteristics are very similar to those of leafy hull sterile1 (lhs1). The map position of OsMADS1 is closely linked to that of lhs1 on chromosome 3. Examination of lhs1 revealed that it contains two missense mutations in the OsMADS1 MADS domain. A genetic complementation experiment showed that the 11.9-kb genomic DNA fragment containing the wild-type OsMADS1 gene rescued the mutant phenotypes. In addition, ectopic expression of the OsMADS1 gene isolated from the lhs1 line resulted in lhs1-conferred phenotypes. These lines of evidence demonstrate that OsMADS1 is the lhs1 gene.

Amino Acid Sequence↗
PubMed2000

Detection and identification of mycobacteria by amplification of the internal transcribed spacer regions with genus- and species-specific PCR primers.

We evaluated the usefulness of PCR assays that target the internal transcribed spacer (ITS) region for identifying mycobacteria at the species level. The conservative and species-specific ITS sequences of 33 species of mycobacteria were analyzed in a multialignment analysis. One pair of panmycobacterial primers and seven pairs of mycobacterial species-specific primers were designed. All PCRs were performed under the same conditions. The specificities of the primers were tested with type strains of 20 mycobacterial species from the American Type Culture Collection; 205 clinical isolates of mycobacteria, including 118 Mycobacterium tuberculosis isolates and 87 isolates of nontuberculous mycobacteria from 10 species; and 76 clinical isolates of 28 nonmycobacterial pathogenic bacterial species. PCR with the panmycobacterial primers amplified fragments of approximately 270 to 400 bp in all mycobacteria. PCR with the M. tuberculosis complex-specific primers amplified an approximately 120-bp fragment only for the M. tuberculosis complex. Multiplex PCR with the panmycobacterial primers and the M. tuberculosis complex-specific primers amplified two fragments that were specific for all mycobacteria and the M. tuberculosis complex, respectively. PCR with M. avium complex-, M. fortuitum-, M. chelonae-, M. gordonae-, M. scrofulaceum-, and M. szulgai-specific primers amplified specific fragments only for the respective target organisms. These novel primers can be used to detect and identify mycobacteria simultaneously under the same PCR conditions. Furthermore, this protocol facilitates early and accurate diagnosis of mycobacteriosis.

Base Sequence↗
PubMed2000

Recruitment and retention in the Navajo Area Indian Health Service.

OBJECTIVE: To determine why physicians and midlevel providers join, leave, or stay in Navajo Area Indian Health Service (IHS). DESIGN: Cross-sectional analysis of data obtained from questionnaires. SETTING: Navajo Area IHS hospitals. SUBJECTS: Navajo Area health care physicians and midlevel health care providers. Main outcome measures The prevalence of physicians and midlevel providers who plan to leave the Navajo Area IHS, the demographic characteristics of these physicians and midlevel providers, and the most common reasons for staying or leaving. RESULTS: A total of 221 (64%) physicians and midlevel providers responded. Of these, 58% planned to leave eventually, and 47% of all physicians and midlevel providers planned to leave in the next 3 years. Physicians and midlevel providers planning to leave tended to be younger than those planning to stay (P: = 0.009). The most common reason to join the IHS was a desire to work in the Southwest, to stay was the quality of the medical staff, and to leave was lack of administrative support. CONCLUSIONS: A high turnover rate of physicians and midlevel providers may occur in the next 3 years. A combination of factors specific to the provider, the institution, and the environment attracts physicians to the Navajo IHS and encourages them to stay. Factors that push physicians and midlevel providers to leave tend to be specific to the institution and are potentially amenable.

Humans↗
PubMed2000

Intrinsic ICAM-1/LFA-1 activation mediates altered responsiveness of atopic asthmatic airway smooth muscle.

Cell adhesion molecules (CAMs) have been importantly implicated in the pathobiology of the airway responses in allergic asthma, including inflammatory cell recruitment into the lungs and altered bronchial responsiveness. To elucidate the mechanism of CAM-related mediation of altered airway responsiveness in the atopic asthmatic state, the expressions and actions of intercellular adhesion molecule-1 (ICAM-1) and its counterreceptor ligand lymphocyte function-associated antigen-1 (LFA-1; i.e., CD11a/CD18) were examined in isolated rabbit airway smooth muscle (ASM) tissues and cultured human ASM cells passively sensitized with sera from atopic asthmatic patients or nonatopic nonasthmatic (control) subjects. Relative to control tissues, the atopic asthmatic sensitized ASM exhibited significantly enhanced maximal contractility to acetylcholine and attenuated relaxation responses to isoproterenol. These proasthmatic changes in agonist responsiveness were ablated by pretreating the atopic sensitized tissues with a monoclonal blocking antibody (MAb) to either ICAM-1 or CD11a, whereas a MAb directed against the related beta(2)-integrin Mac-1 had no effect. Moreover, relative to control tissues, atopic asthmatic sensitized ASM cells displayed an autologously upregulated mRNA and cell surface expression of ICAM-1, whereas constitutive expression of CD11a was unaltered. Extended studies further demonstrated that 1) the enhanced expression and release of soluble ICAM-1 by atopic sensitized ASM cells was prevented when cells were pretreated with an interleukin (IL)-5-receptor-alpha blocking antibody and 2) administration of exogenous IL-5 to naive (nonsensitized) ASM cells induced a pronounced soluble ICAM-1 release from the cells. Collectively, these observations provide new evidence demonstrating that activation of the CAM counterreceptor ligands ICAM-1 and LFA-1, both of which are endogenously expressed in ASM cells, elicits autologously upregulated IL-5 release and associated changes in ICAM-1 expression and agonist responsiveness in atopic asthmatic sensitized ASM.

Animals↗
PubMed2000

Hoxa-5 in mouse developing lung: cell-specific expression and retinoic acid regulation.

Hoxa-5 is a homeobox gene that is highly expressed in the developing mouse lung. However, little is known about the molecular mechanisms controlling expression. We characterized the ontogeny of Hoxa-5 gene and protein expressions during lung development and then studied the cell-specific effects of retinoic acid (RA) on Hoxa-5 mRNA in fetal lung fibroblasts and MLE-12 mouse lung epithelial cells. Strong but constant Hoxa-5 gene and protein expressions were detected from mouse lung on embryonic day 13.5 to postnatal day 2. At baseline, the gene was strongly expressed in the fibroblasts of day 17.5 fetal mouse lungs. A very weak but reproducible expression was present in the MLE-12 cells. RA stimulated gene expression in both cell types in a time- and dose-dependent manner. Peak expression occurred much later in the MLE-12 cells compared with that in fibroblasts. Cycloheximide and actinomycin D treatment studies suggested that the differences in RA effect on each cell type may involve the presence of a repressor that can be overcome by RA.

Aging↗
PubMed2000

Concentrated ambient air particles induce mild pulmonary inflammation in healthy human volunteers.

We tested the hypothesis that exposure of healthy volunteers to concentrated ambient particles (CAPS) is associated with an influx of inflammatory cells into the lower respiratory tract. Thirty-eight volunteers were exposed to either filtered air or particles concentrated from the immediate environment of the Environmental Protection Agency (EPA) Human Studies Facility in Chapel Hill, North Carolina. Particle concentrations in the chamber during the exposures ranged from 23.1 to 311.1 microgram/m(3). While in the exposure chamber, volunteers alternated between moderate exercise (15 min) and rest (15 min) for a total exposure time of 2 h. There were no symptoms noted by volunteers after the exposure. Similarly, there were no decrements in pulmonary function. Eighteen hours after exposure, analysis of cells and fluid obtained by bronchoalveolar lavage showed a mild increase in neutrophils in both the bronchial and alveolar fractions in those individuals exposed to CAPS (8.44 +/- 1.99 and 4.20 +/- 1.69%, respectively, in those with the greatest exposure) relative to filtered air (2.69 +/- 0.55 and 0.75 +/- 0.28%, respectively). Blood obtained 18 h after exposure to CAPS contained significantly more fibrinogen relative to samples obtained before exposure. We conclude that ambient air particles are capable of inducing a mild inflammation in the lower respiratory tract, as well as an increased concentration of blood fibrinogen.

Adult↗
PubMed2000

Studies on human pregnancy-induced insulin-like growth factor (IGF)-binding protein-4 proteases in serum: determination of IGF-II dependency and localization of cleavage site.

Insulin-like growth factor (IGF)-binding protein-4 (IGFBP-4), a consistent inhibitor of IGF action, is subject to proteolytic cleavage by the IGF-II-dependent IGFBP-4 protease. However, regulation of the IGF-II-dependent IGFBP-4 protease in vivo is not known. As IGFBP proteases are known to be triggered during pregnancy, we systematically evaluated the changes in IGFBP-4 proteolysis by serum collected throughout human pregnancy. Results from in vitro protease assays using recombinant IGFBP-4 revealed that IGFBP-4 proteolysis determined in both the presence and absence of exogenous IGF-II significantly increased during the first and second trimesters and reached a plateau by the third trimester. However, in the absence of IGF-II, IGFBP-4 proteolysis by pregnancy serum was only observed after prolonged incubation. IGF-II dose dependently increased IGFBP-4 proteolysis by pregnancy serum, with maximal stimulation observed at a concentration of 0.7 mol/L relative to IGFBP-4. In contrast, IGF-II at an equimolar dose had little effect on proteolysis of recombinant human IGFBP-3, whereas excess IGF-II reproducibly inhibited recombinant human IGFBP-3 proteolysis by pregnancy serum. Although IGF-II enhanced IGFBP-4 proteolysis, results from N-terminal sequence and mass spectrometric analyses of IGFBP-4 proteolytic fragments demonstrate that the cleavage site (Met135-Lys136) in human IGFBP-4 was not altered by IGF-II. Deletion of the residues 121-141 containing this cleavage site blocked IGFBP-4 proteolysis. These findings demonstrate that the increase in IGFBP-4 proteolysis during pregnancy was accounted for mainly by the IGF-II-dependent IGFBP-4 proteolysis. Because IGFBP-4 is a potent inhibitor of IGF actions, it can be speculated that the pregnancy-induced IGFBP-4 proteases may play an important role in regulating fetal growth.

Adult↗
PubMed2000

Cloning and sequence analysis of the estA gene encoding enzyme for producing (R)-beta-acetylmercaptoisobutyric acid from Pseudomonas aeruginosa 1001.

The estA gene encoding the enzyme that catalyzes the production of (R)-beta-acetylmercaptoisobutyric acid from (R,S)-ester from Pseudomonas aeruginosa 1001, was cloned in Escherichia coli and its nucleotide sequence was determined, revealing the presumed open reading frame encoding a polypeptide of 316 amino acid residues (948 nucleotides). The overall A + T and C + G compositions were 32.59% and 67.41%, respectively. The amino acid sequence of the estA gene product showed a significant similarity with that of the triacylglycerol lipase from Psychrobacter immobilis (38% identity), triacylglycerol lipase from Moraxella sp. (36% identity), and two forms of carboxyl esterases from Acinetobacter calcoaceticus (17% and 17% identities). The deduced amino acid sequences have a pentapeptide consensus sequence, G-X-S-X-G, having an active serine residue, and another active site, dipeptides H-G, located at 70-100 amino acids upstream of the G-X-S-X-G consensus sequence.

Journal Article↗
PubMed2000

Use of insulin pump therapy at nighttime only for children 7-10 years of age with type 1 diabetes.

OBJECTIVE: Because of age-related developmental and cognitive issues, children <10 years of age may not be able to wear an insulin pump safely when they are not under direct parental supervision. The purpose of this study was to determine if insulin pump therapy at nighttime only, when children are at home, could improve fasting and nighttime blood glucose levels without adverse effects. RESEARCH DESIGN AND METHODS: The study cohort consisted of 10 children aged 7-10 years. A randomized crossover design was used to compare nighttime-only pump usage from dinner and throughout the night, combined with a prebreakfast injection of intermediate-acting NPH and rapid-acting lispro insulin, with 3 insulin injections per day. Comparisons were made among mean blood glucose values and percentage of blood glucose levels within the target range (70-150 mg/dl) before meals, at bedtime, and at 3:00 A.M.; serum fructosamine levels; and scores on measures of adherence and fear of hypoglycemia. RESULTS: Compared with baseline levels, the use of the pump resulted in a significant decrease in the mean average (P < 0.001), breakfast (P < 0.0001), and 3:00 A.M. (P < 0.003) blood glucose levels. There was a decrease in the percentage of blood glucose values less than the target range (P < 0.01) and in fructosamine (P < 0.01) values and an increase in the percentage of blood glucose levels within the target range (P < 0.03). CONCLUSIONS: Nighttime-only insulin pump therapy may be a viable alternative that young children can use to improve glycemia when they are not capable of independently managing an insulin pump.

Child↗
PubMed2000

Toward an explanation of the power law artifact: insights from response surface analysis.

The power law (y = ax-b) has been shown to provide a good description of data collected in a wide range of fields in psychology. R. B. Anderson and Tweney (1997) suggested that the model's data-fitting success may in part be artifactual, caused by a number of factors, one of which is the use of improper data averaging methods. The present paper follows up on their work and explains causes of the power law artifact. A method for studying the geometric relations among responses generated by mathematical models is introduced that shows the artifact is a result of the combined contributions of three factors: arithmetic averaging of data that are generated from a nonlinear model in the presence of individual differences.

Behavior↗
PubMed2000

Differential transcriptional regulation of silencer of death domains in cord blood and peripheral blood lymphocytes.

We have shown that neonatal lymphocytes are deficient in TNF-induced apoptosis. Recently, a 60 kDa protein termed silencer of death domains (SODD) has been shown to prevent spontaneous apoptosis. The binding of SODD to DD of the TNFR-I maintains DD in monomeric form and prevents their aggregation which is required for the apoptotic signal. We examined the expression of SODD mRNA during TNF-induced apoptosis. Although in non-stimulated cord blood lymphocytes the constitutive expression of SODD mRNA was lower than that of non-stimulated peripheral blood lymphocytes, following anti-CD3 stimulation SODD mRNA was significantly increased in cord blood lymphocytes at 12 and 24 h, returning to the baseline at 48 h. In contrast, a modest decrease in SODD transcript was observed in peripheral blood lymphocytes. Furthermore, TNF downregulated SODD mRNA expression in peripheral blood lymphocytes, whereas it had no significant effect on SODD transcripts in cord blood lymphocytes. Therefore, differential regulation of SODD may be one of the mechanisms responsible for decreased TNF-induced apoptosis in neonatal lymphocytes.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Roles of oxidation-reduction potential in electrolyzed oxidizing and chemically modified water for the inactivation of food-related pathogens.

This study investigates the properties of electrolyzed oxidizing (EO) water for the inactivation of pathogen and to evaluate the chemically modified solutions possessing properties similar to EO water in killing Escherichia coli O157:H7. A five-strain cocktail (10(10) CFU/ml) of E. coli O157:H7 was subjected to deionized water (control), EO water with 10 mg/liter residual chlorine (J.A.W-EO water), EO water with 56 mg/liter residual chlorine (ROX-EO water), and chemically modified solutions. Inactivation (8.88 log10 CFU/ml reduction) of E. coli O157:H7 occurred within 30 s after application of EO water and chemically modified solutions containing chlorine and 1% bromine. Iron was added to EO or chemically modified solutions to reduce oxidation-reduction potential (ORP) readings and neutralizing buffer was added to neutralize chlorine. J.A.W-EO water with 100 mg/liter iron, acetic acid solution, and chemically modified solutions containing neutralizing buffer or 100 mg/liter iron were ineffective in reducing the bacteria population. ROX-EO water with 100 mg/liter iron was the only solution still effective in inactivation of E. coli O157:H7 and having high ORP readings regardless of residual chlorine. These results suggest that it is possible to simulate EO water by chemically modifying deionized water and ORP of the solution may be the primary factor affecting microbial inactivation.

Animals↗
PubMed2000

Ultraviolet spectrophotometric characterization and bactericidal properties of electrolyzed oxidizing water as influenced by amperage and pH.

To identify the primary component responsible in electrolyzed oxidizing (EO) water for inactivation, this study determined the concentrations of hypochlorous acid (HOCl) and hypochlorite ions (OCl-) and related those concentrations to the microbicidal activity of the water. The ultraviolet absorption spectra were used to determine the concentrations of HOCl and OCl- in EO water and the chemical equilibrium of these species with change in pH and amperage. EO water generated at higher amperage contained a higher chlorine concentration. The maximum concentration of HOCl was observed around pH 4 where the maximum log reduction (2.3 log10 CFU/ml) of Bacillus cereus F4431/73 vegetative cells also occurred. The high correlation (r = 0.95) between HOCl concentrations and bactericidal effectiveness of EO water supports HOCl's role as the primary inactivation agent. Caution should be taken with standard titrimetric methods for measurement of chlorine as they cannot differentiate the levels of HOCl present in EO water of varying pHs.

Bacillus cereus↗
PubMed2000

Epidemiology of diphtheria in South Dakota.

Respiratory diphtheria was one of the most common causes of death among children in the pre-vaccine era. Since the introduction of diphtheria toxoid vaccine in 1920s, and its widespread use by the late 1940s, diphtheria became increasingly rare in the United States. However, through the 1970s diphtheria remained endemic in some states, with reported incidence rates > 1.0 per million population in six states (Alaska, Arizona, Montana, New Mexico, South Dakota, and Washington). Starting in 1980, less than five cases have been reported each year in the United States. The majority of culture-confirmed cases have been associated with importation from other countries. Toxigenic Corynebacterium diphtheriae, the organism causing diphtheria, was thought to have become rare or even have disappeared from previously endemic areas such as South Dakota. However, during four months in 1996, 11 persons (one index case, six patients and four household contacts) in an American Indian community in South Dakota were found to be infected by C. diphtheriae; six of these isolates were toxigenic. The findings in this report indicate that despite 20 years without reported respiratory diphtheria cases, toxigenic C. diphtheriae is still present in South Dakota. The continuous circulation of toxigenic strains of C. diphtheriae emphasizes the need for health care providers throughout South Dakota to promote timely vaccination against diphtheria among persons of all ages and ethnic groups, to be aware of the clinical signs and symptoms of diphtheria so that cases can be promptly diagnosed and treated, and further public health measures can be taken to contain this serious disease.

Adolescent↗