Search PubMed⌕ Search

Biomedical subjects

H Lee

Publications and source records attributed to H Lee.

At least 505 records · Page 28Linked to original sources
PubMed1996

Survival of luxAB-marked Alcaligenes eutrophus H850 in PCB-contaminated soil and sediment.

A rifampicin-resistant PCB-degrading Alcaligenes eutrophus H850 strain was marked with luxAB reporter genes and designated H850Lr. This strain was enumerated in soil by viable plating and counting of light-emitting colonies. The marked strain was also inoculated into soil and sediment microcosms contaminated with PCBs and treated with rhamnolipid biosurfactants produced by Pseudomonas aeruginosa UG2Lr or inoculated with the P. aeruginosa UG2Lr strain. A. eutrophus H850Lr exhibited similar survival in sandy loam soil in the absence or presence of PCBs over 56 days. Survival of A. eutrophus H850Lr in PCB-contaminated sediment was less than in sandy soil under the same incubation conditions. Addition of P. aeruginosa UG2 rhamnolipids to soil increased the culturable indigenous heterotrophic population, and numbers of A. eutrophus H850Lr cells. P. aeruginosa UG2Lr cells did not affect survival of A. eutrophus H850, as cell enumerations after 2 months were the same as in microcosms containing only A. eutrophus H850 inoculum. P. aeruginosa UG2Lr survived in soils as demonstrated by the slight decrease in CFU from 1 x 10(8) to 2 x 10(6) CFU cm-3 after 2 months. Direct extraction of DNA from soil and purification for use in PCR amplification using primers specific for the bphC gene detected 8 x 10(2) A. eutrophus H850Lr CFU g-1 soil in PCB-contaminated soils. Colony lifts of bacteria isolated from microcosms containing PCB-contaminated soil did not hybridize with LB400 bphC probe. However, enrichment of PCB-contaminated soil with biphenyl, followed by DNA extraction and probing with bphC gene probe detected indigenous PCB-degrading bacteria containing a similar gene sequence in PCB-contaminated sediment. This study demonstrates the usefulness of using the lux reporter system in monitoring bacterial survival in PCB-contaminated soils and sediments.

Alcaligenes↗
PubMed1996

Two distinct forms of USF in the Lytechinus sea urchin embryo do not play a role in LpS1 gene inactivation upon disruption of the extracellular matrix.

Recent studies in our laboratory indicated that the upstream stimulatory factor (USF) in the sea urchin embryo of Lytechinus acts as a transcriptional repressor for the aboral ectoderm-specific expression of the LpS1 genes. Disruption of the extracellular matrix (ECM) arrests development prior to gastrulation and inactivates the LpS1 genes. We wanted to determine whether the inactivation of the LpS1 genes by ECM disruption may be due to an increase in USF expression. In the course of the investigation, a second L, variegatus USF cDNA clone (LvUSF2) was isolated and sequenced. The deduced amino acid sequence of LvUSF2 is nearly identical to LvUSF1 except at the amino end, where they are sharply divergent. Like LvUSF1, LvUSF2 has a USF-specific, a basic/hefixloop-helix, and a leucine zipper domain. Genomic DNA blots indicated that the two cDNA clones are derived from one gene, which suggested that the Lytechinus USF1 and USF2 mRNAs, of approximately 6.0 and 4.0 kb, respectively, are the result of differential RNA splicing. ECM disruption in Lytechinus embryos caused a relative drop in USF RNA accumulation levels to approximately 60% of control embryos, while LpS1 RNA accumulation levels dropped to less than 5%. USF protein levels and DNA binding activities in ECM-disrupted embryos also dropped to approximately 60% to that of control embryos. A mutation at the USF binding site in an LpS1 promoter-chloramphenicol acetyl transferase (CAT) fusion DNA construct did not cause a relative increase in CAT activity in ECM disrupted embryos. These results suggest that the induced drop in LpS1 gene expression by ECM disruption is not due to an increase in the repressive activity of USF.

Amino Acid Sequence↗
PubMed1996

Effect of grapefruit juice on the pharmacokinetics and pharmacodynamics of quinidine in healthy volunteers.

A study was conducted to examine the effect of grapefruit juice on the disposition of quinidine sulfate and changes of QT intervals after oral administration to twelve healthy male volunteers. Participants received two oral doses of quinidine sulfate tablets (400 mg) with 240 mL of water or grapefruit juice, each separated by a 1-week washout period. Plasma samples for analysis of quinidine and its major metabolite, 3-hydroxyquinidine, were collected for a 24-hour period and analyzed by a high-performance liquid chromatography method. For pharmacodynamic data, the electrocardiograms (ECGs) were performed for 12 hours, and the recordings were marked for ECG interval at all blood collection time periods. There was no significant difference in pharmacokinetic parameters of quinidine when administered with grapefruit juice or water, except for time to maximum concentration (tmax), which was 1.6 hours after administration with water and 3.3 hours after administration with grapefruit juice. Administration with grapefruit juice also resulted in a 33% decrease in the area under the concentration-time curve (AUC) of 3-hydroxyquinidine compared with water, but did not increase the AUC of quinidine or change the ratio of AUC of 3-hydroxyquinidine to the AUC of quinidine. Pharmacodynamic parameters, including changes in the rate-corrected QT (QTc) interval, closely paralleled the pharmacokinetic data, in that administration with grapefruit juice led to delayed maximal effect on QTc and reduction in maximal effect. Administration with grapefruit juice therefore delays the absorption of quinidine and inhibits the metabolism of quinidine to 3-hydroxyquinidine.

Anti-Arrhythmia Agents↗
PubMed1996

Function of 3' non-coding sequences and stop codon usage in expression of the chloroplast psaB gene in Chlamydomonas reinhardtii.

The rate of mRNA decay is an important step in the control of gene expression in prokaryotes, eukaryotes and cellular organelles. Factors that determine the rate of mRNA decay in chloroplasts are not well understood. Chloroplast mRNAs typically contain an inverted repeat sequence within the 3' untranslated region that can potentially fold into a stem-loop structure. These stem-loop structures have been suggested to stabilize the mRNA by preventing degradation by exonuclease activity, although such a function in vivo has not been clearly established. Secondary structures within the translation reading frame may also determine the inherent stability of an mRNA. To test the function of the inverted repeat structures in chloroplast mRNA stability mutants were constructed in the psaB gene that eliminated the 3' flanking sequences of psaB or extended the open reading frame into the 3' inverted repeat. The mutant psaB genes were introduced into the chloroplast genome of Chlamydomonas reinhardtii. Mutants lacking the 3' stem-loop exhibited a 75% reduction in the level of psaB mRNA. The accumulation of photosystem I complexes was also decreased by a corresponding amount indicating that the mRNA level is limiting to PsaB protein synthesis. Pulse-chase labeling of the mRNA showed that the decay rate of the psaB mRNA was significantly increased demonstrating that the stem-loop structure is required for psaB mRNA stability. When the translation reading frame was extended into the 3' inverted repeat the mRNA level was reduced to only 2% of wild-type indicating that ribosome interaction with stem-loop structures destabilizes chloroplast mRNAs. The non-photosynthetic phenotype of the mutant with an extended reading frame allowed us to test whether infrequently used stop codons (UAG and UGA) can terminate translation in vivo. Both UAG and UGA are able to effectively terminate PsaB synthesis although UGA is never used in any of the Chlamydomonas chloroplast genes that have been sequenced.

Amino Acid Sequence↗
PubMed1996

Radiation-induced lung injury in vivo: expression of transforming growth factor-beta precedes fibrosis.

Cytokine release from irradiated cells has been postulated to start soon after irradiation preceding detectable clinical and pathological manifestation of lung injury. The expression of transforming growth factor beta (TGF beta), a fibrogenic and radiation-inducible cytokine, was studied from 1-16 weeks after the 15 and 30 Gray (Gy) of thoracic irradiation to rats. Thoracic irradiation caused an increase in TGF beta protein in bronchoalveolar lavage (BAL) fluid peaking at 3-6 weeks as compared to sham-irradiated control rats. Steady state TGF beta mRNA expression as shown by whole lung northern blot assay paralleled the TGF beta protein expression in BAL fluid. The peak of TGF beta protein increase in BAL fluid between 3 and 6 weeks coincided with the initial influx of inflammatory cells in BAL fluid, but preceded histologically discernable pulmonary fibrosis that was not apparent until 8-10 weeks after irradiation. In conclusion. TGF beta and mRNA and protein upregulation preceded the radiation-induced pulmonary fibrosis, suggesting a pathogenetic role in the development of radiation fibrosis.

Animals↗
PubMed1996

Inter-observer reliability of ten tests used for predicting difficult tracheal intubation.

PURPOSE: To determine inter-observer reliability of ten preoperative airway assessment tests used for predicting difficult tracheal intubation. METHOD: We prospectively assessed 59 patients undergoing elective surgery requiring tracheal intubation at a large metropolitan teaching hospital. Two experienced observers independently conducted the airway assessment tests on the same group of patients. Inter-observer reliability was examined using Kappa (K) and intraclass correlation coefficient (ICC). RESULTS: Two tests--mouth opening (ICC = 0.93) and chin protrusion (ICC = 0.89)--had excellent inter-observer reliability. Seven tests--thyromental distance (ICC - 0.74), subluxation (K = 0.66), atlanto-occipital extension distance (ICC = 0.67) and angle (K = 0.66), profile classification (K = 0.58), ramus length (ICC = 0.53), oropharyngeal best view (K = 0.49)--were moderately reliable. One test--Mallampati technique of assessing oropharyngeal view (K = 0.31)--had poor reliability. CONCLUSION: Many of the preoperative airway tests have only moderate inter-observer reliability. This may provide some insight into why previous research has failed to show that the tests accurately predict difficult tracheal intubation.

Atlanto-Occipital Joint↗
PubMed1996

Diacylglycerylgalactosides from Arisaema amurense.

Previously undescribed 1,2-O-diacyl-3-O-beta-D-galactopyranosyl glycerols and 1,2-O-diacyl-3-O-[alpha-D-galactopyranosyl-(1"-->6')-O-beta-D- galactopyranosyl] glycerols were isolated as single components from Arisaema amurense. The cytotoxicities of these compounds against P388 and DLD-1 are described.

Animals↗
PubMed1996

Liver transplantation and its long-term management in children.

Liver transplantation is an effective treatment for end-stage liver disease in the pediatric population. The 1-year survival rate in the United States is now approximately 80%, with some series showing a 90% 1-year survival rate. Most children who receive liver transplantation attain normal growth and development. Many pitfalls remain, however, in the treatment for pediatric liver disease with transplantation, including donor-organ scarcity and immunosuppression-related side effects. This article reviews indications for liver transplantation and clinical management of patients who receive liver transplantation.

Adolescent↗
PubMed1996

Low prevalence of immunogenetic markers of IDDM in adult Koreans with diabetes detected on OGTT.

In the Asian populations, it is not uncommon for adult patients with NIDDM to eventually lose beta-cell function and develop IDDM. Accepting that IDDM is an autoimmune disease, which occurs on a genetic background, it could by hypothesized that by measuring autoantibody prevalence and HLA DQ gene polymorphism, known important prediagnostic markers of IDDM, the prevalence of adult-onset IDDM in patients with previously undiagnosed NIDDM patients could be estimated. To do this, anti-GAD prevalence and HLA DQ A1 and DQ B1 polymorphisms after PCR amplification of genomic DNA were analyzed in 121 newly diagnosed diabetic patients of Yonchon cohort and compared to the results with those of 100 matched health control subjects. We also compared the results with those of other populations to assess the difference of genotype distribution. The overall prevalence of anti-GAD antibodies was 1.7% (2 of 121) in patients with previously undiagnosed NIDDM, whereas 1 of 100 controls had positive antibodies. Among those who were positive, their titer of antibodies to GAD were not high. No statistically significant differences in the distribution of either mean levels of anti-GAD or DQA1 and DQB1 alleles were found comparing NIDDM patients to controls. Interestingly, the frequency of DQB1*non-Asp-57 and DQA1*Arg-52 alleles in the Korean adult control population was similar to that of US Caucasians (DQB1*non-Asp-57: 0.431 vs. 0.475; DQA1*Arg-52: 0.492 vs. 0.463). The low prevalence of anti-GAD antibodies and HLA-DQA1 and DQB1 susceptibility alleles among recent-onset NIDDM patients, not different compared to controls suggests that diabetes in Korean adults is unlikely to have an autoimmune component to its pathogenesis.

Adult↗
PubMed1996

Community-based epidemiologic study on atherosclerotic cardiovascular risk factors.

The present study was undertaken to determine the prevalence of hyperlipidemia and to find out the possible impact of serum lipid profiles on other cardiovascular risk factors in Yonchon County, Korea. Population-based cross-sectional study by random cluster sampling of registered residents over 30 years of age was performed. Out of the 3804 subjects scheduled for the survey, 2520 underwent the actual examination. The prevalence of hypercholesterolemia (serum cholesterol > or = 240 mg/dl) was only 1.2%, whereas that of hypertriglyceridemia (serum triglyceride > or = 250 mg/dl) was as high as 11.3%. The serum levels of cholesterol, triglyceride and HDL cholesterol correlated with anthropometric indices, body mass indices and waist hip ratios. The prevalences of diabetes and/or hypertension increased as either serum cholesterol or triglyceride level increased. In addition, the prevalence rates of obesity, impaired glucose tolerance, hypertriglyceridemia and hypercholesterolemia in its isolated form (free of the others) were much lower than overall prevalence indicating an existence of major overlap among these cardiovascular atherosclerotic risk factors in the form of multiple combinations. Central obesity was found to be an independent associated factor for the aggregation of the conditions related to the increase in cardiovascular risks. The prevalence of hypercholesterolemia in Yonchon County was substantially lower than that previously suggested, albeit that of hypertriglyceridemia was very high. We could also observe a varying degree of transition in cardiovascular risks related to insulin resistance from the rural to the urban area with rapid emergence of non-communicable diseases as a result of modernization.

Adult↗
PubMed1996

Use of the clock drawing task in the diagnosis of mild and very mild Alzheimer's disease.

The purpose of this study was to examine the utility of the clock drawing task (CDT) in differentiating between patients with mild and very mild Alzheimer's disease (AD) and normal controls. Thirty normal elderly individuals and 30 patients with probable AD were entered into the study and asked, in a standard fashion, to draw a clock from memory. All the clocks were scored according to two previously described standardized scoring systems, and the accuracy of classification into normal or AD groups was determined. Both CDT scales could discriminate between moderate AD and normal aging but lacked sensitivity in the very mild AD cases; mild cases showed intermediate sensitivity. In conclusion, the CDT as a test for AD is insensitive in the early-stage cases, but sensitivity improves with increasing severity of dementia. The CDT is unlikely to be useful in distinguishing between AD in its early stages and normal aging.

Aged↗
PubMed1996

Associations among PH and SH3 domain-containing proteins and Rho-type GTPases in Yeast.

The src homology region 3 (SH3) domain-bearing protein Bem1p and the Rho-type GTPase Cdc42p are important for bud emergence in Saccharomyces cervisiae. Here, we present evidence that through its second SH3 domain, Bem1p binds to the structurally and functionally similar proteins Boi1p and Boi2p, each of which contain an SH3 and pleckstrin homology (PH) domain. Deletion of BOI1 and BO12 together leads to impaired morphogenesis and poor ability. A PH domain-bearing segment of Boi1p that lacks the Bem1p-binding site is necessary and sufficient for function. This segment of Boi1p displays a two-hybrid interaction with Cdc42p, suggesting that Boi1p either binds directly to or is part of a larger complex that contains Cdc42p. Consistent with these possibilities, overexpression of Boi1p inhibits bud emergence, but this inhibition is counteracted by cooverexpression of Cdc42p. Increased expression of the Rho-type GTPase Rho3p, which is implicated in bud growth defects of boil boi2 mutants, suggesting that Boi1p and Boi2p may also play roles in the activation or function of Rho3p. These findings provide an example of a tight coupling in function between PH domain-bearing proteins and both Rho-type GTPases and SH3 domain-containing proteins, and they raise the possibility that Boi1p and Boi2 play a role in linking the actions of Cdc42p and Rho3p.

Adaptor Proteins, Signal Transducing↗
PubMed1996

STAT testing? A guideline for meeting clinician turnaround time requirements. Practice parameter.

This practice parameter, developed by the Practice Parameters and Outcomes Measurement Committee of the American Society of Clinical Pathologists (ASCP), is a guideline for the development of reasonable stat lists. Stat testing lists vary according to practice setting. Furthermore, although stat lists exist, extenuating clinical circumstances may warrant performing a test stat that is otherwise considered routine. Successful development of a stat testing list requires organizations to take an interdisciplinary approach, focusing on clinical and operational considerations of both the care provider and the clinical laboratory.

Ambulatory Care↗
PubMed1996

Suppressive effects of methyl methacrylate on the mutagenicity and DNA adduct formation induced by 1-nitropyrene and benzo[a]pyrene.

Methyl methacrylate (MMA) is widely used as a cement in dentistry, orthopaedic surgery and ophthalmology. Studies based on short-term genotoxicity tests have produced conflicting results in the last two decades. In the present study, the effects of MMA on the mutagenicity of 1-nitropyrene (1-NP) and benzo[a]pyrene (B[a]P) were evaluated with the Salmonella typhimurium TA98 strain in the absence and presence of S9 mix. The direct-acting mutagenicity of 1-NP was markedly decreased by MMA in a dose-dependent manner. However, a low inhibitory effect of MMA on the metabolic-acting mutagenicity of B[a]P was observed. MMA did not show mutagenicity within the concentrations of 4.7-37.6 microM either with or without S9 mix. The inhibitory effect of MMA was not due to its cytotoxicity because very low and/or no cytotoxicity of MMA to S. typhimurium TA98 was observed. To confirm the antimutagenicity of MMA against 1-NP and B[a]P, a 32P-postlabelling method was used to determine whether MMA modified DNA adduct formation produced by both compounds in calf thymus DNA. MMA inhibits the formation of 1-NP- and B[a]P-DNA adducts in a dose-dependent manner. The DNA adduct of 1-NP reduced by MMA was greater than that of B[a]P. Thus, we suggested that MMA was possibly acting as an inhibitor of chemical carcinogenesis.

Animals↗
PubMed1996

Naturally occurring diallyl disulfide inhibits the formation of carcinogenic heterocyclic aromatic amines in boiled pork juice.

Three heterocyclic aromatic amines, 2-amino-3-methyl-imidazo[4, 5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoxaline and 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, have been found in boiled pork juice. We have investigated the effect of naturally occurring organosulfur compounds, which are present in garlic and onion, on mutagen formation in boiled pork juice. Six organosulfur compounds - diallyl disulfide (DAD), dipropyl disulfide (DPD), diallyl sulfide (DAS), allyl methyl sulfide (AMS), allyl mercaptan (AM) and cysteine - were added separately to the pork juice before reflux boiling and then the mutagenicity of each sample was examined with the Salmonella typhimurium strain TA98 in the presence of S9 mix. All six compounds were found to inhibit the mutagenicity of boiled pork juice. The greatest inhibitory effect was observed with DAD and DPD, and this was 111-fold higher than that of the lowest, cysteine. To elucidate the inhibitory effect of DAD on mutagen formation in boiled pork juice, the major mutagenic fractions were monitored after HPLC separation by their mutagenicity with S. typhimurium TA98. By comparing the retention times of authentic IQ compounds from boiled pork juice with those following the addition of DAD, we showed that the mutagenicity of three major fractions was significantly inhibited compared with those same fractions in boiled pork juice alone. In addition, the Maillard reaction products (MRPs) in the boiled pork juice with and without the addition of DAD were quantified and identified by capillary gas chromatography and gas chromatography-mass spectrometry. The results show that the reduction in the total amount of MRPs (pyridines, pyrazines, thiophenes and thiazoles) in boiled pork juice after boiling for 12 h is correlated with their mutagenicity. Among the MRPs, tetrahydrothiophene-3-one exhibited the strongest correlation. These data suggest that the inhibition of IQ mutagen formation by DAD is mediated through the reduction of MRPs production.

Allyl Compounds↗
PubMed1996

Carpal tunnel release through a limited skin incision under direct visualization using a new instrument, the carposcope.

A new surgical technique with a set of instruments has been developed for the release of carpal tunnel. The technique allows division of the transverse carpal ligament through a short transverse skin incision (1.5 to 2 cm) of the wrist flexion crease under direct visualization. The technique has been used on 237 patients for 275 cases of carpal tunnel release (38 bilateral). Following the release, median time to activities of daily living was 7 days for 60 compensation patients and 6 days for 193 noncompensation patients (22 patients provided no information on the activities of daily living). The median time to return to work was 49 days for 51 compensation workers and 20 days for 64 noncompensation workers. The overall relief rate of preoperative symptoms was 86 percent (90 percent for noncompensation patients, 82 percent for compensation patients). There were no intraoperative complications among our studies of 275 cases by two surgeons (176 cases by the senior author). The described technique of carpal tunnel release is a useful alternative to open carpal tunnel release because of decreased short-term postoperative morbidity and to the endoscopic carpal tunnel release because of the simplicity and the lower cost of instrumentation.

Activities of Daily Living↗
PubMed1996

Novel osmotically induced antifungal chitinases and bacterial expression of an active recombinant isoform.

NaCl (428 mM)-adapted tobacco (Nicotiana tabacum L. var Wisconsin 38) cells accumulate and secrete several antifungal chitinases. The predominant protein secreted to the culture medium was a 29-kD peptide that, based on internal amino acid sequence, was determined to be a class II acidic chitinase with similarity to PR-Q. The four predominant chitinases (T1, T2, T3, and T4) that accumulated intracellularly in 428 mM NaCl-adapted cells were purified. Based on N-terminal sequence analyses, two of these were identified as class I chitinase isoforms, one similar to the N. tomentosiformis (H. Shinshi, J.M. Neuhaus, J. Ryals, F. Meins [1990] Plant Mol Biol 14:357-368) protein (T1) and the other homologous to the N. sylvestris (Y. Fukuda, M. Ohme, H. Shinshi [1991] Plant Mol Biol 16:1-10) protein (T2). The other two proteins (T3 and T4) were determined to be novel chitinases that have sequence similarity with class I chitinases, but each lacks a chitin-binding domain. All four chitinases inhibited Fusarium oxysporum f. sp. lycopersici and Trichoderma longibrachiatum hyphal growth in vitro, although the isoforms containing a chitin-binding domain were somewhat more active. Conditions were established for the successful expression of soluble and active bacterial recombinant T2. Expression of soluble recombinant T2 was achieved when isopropyl beta-D-thiogalactopyranoside induction occurred at 18 degrees C but not at 25 or 37 degrees C. The purified recombinant protein exhibited antifungal activity comparable to a class I chitinase purified from NaCl-adapted tobacco cells.

Antifungal Agents↗