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Biomedical subjects

H Lee

Publications and source records attributed to H Lee.

At least 163 records · Page 9Linked to original sources
PubMed2001

Managing health habits for myocardial infarction (MI) patients.

The study examined effects of the heart camp as a motivation enhancement program on cardiac risk reduction and behavioral modification in myocardial infarction (MI) patients. A total of 86 outpatients participated at the first heart camp and 45 returned to the second one in 8 weeks. The first and second heart camps were daylong programs consisted of health assessment, education classes, and Q&A session with interdisciplinary team approach. At the completion of the heart camp, the participants showed significantly lower scores in cardiac risk factors, and significant improvements in motivational variables, especially, perceived benefits and perceived barriers as well as in the performance of diet and exercise behaviors. The study results confirm that it is possible to enhance motivation for chronic patients like MI patients by even short period of comprehensive educational program.

Adult↗
PubMed2001

Cleaning strategies for flux recovery of an ultrafiltration membrane fouled by natural organic matter.

One of the most common problems encountered in water treatment applications of membranes is fouling. Natural organic matter (NOM) represents a particularly problematic foulant. Membranes may be fouled by relatively hydrophilic and/or hydrophobic NOM components, depending on NOM characteristics, membrane properties, and operating conditions. To maximize flux recovery for an NOM-fouled ultrafiltration membrane (NTR 7410), chemical cleaning and hydraulic rinsing with a relatively high cross-flow velocity were investigated as cleaning strategies. The modification of the membrane surface with either an anionic or a cationic surfactant was also evaluated to minimize membrane fouling and to enhance NOM rejection. Foulants from a hydrophobic NOM source (Orange County ground water (OC-GW)) were cleaned more effectively in terms of permeate flux by acid and caustic cleanings than foulants from a relatively hydrophilic NOM source (Horsetooth surface water (HT-SW)). An anionic surfactant (sodium dodecyl sulfate (SDS)) was not effective as a cleaning agent for foulants from either hydrophobic or hydrophilic NOM sources. High ionic strength cleaning with 0.1 M NaCl was comparatively effective in providing flux recovery for NOM-fouled membranes compared to other chemical cleaning agents. Increased cross-flow velocity and longer cleaning time influenced the efficiency of caustic cleaning, but not high ionic strength cleaning. The membrane was successfully modified only with the cationic surfactant; however, enhanced NOM rejection was accompanied by a significant flux reduction.

Acids↗
PubMed2001

15-year outcome of treated bipolar disorder.

BACKGROUND: Prior reports suggested that bipolar patients in Taiwan had comparable long-term outcome to Western patients despite markedly lower rates of co-occurring substance use disorders. Thus, predictors of long-term outcome identified from Taiwanese bipolar samples may be less influenced by substance abuse. METHODS: One hundred and one patients with bipolar disorder (DSM-III-R) having been naturalistically treated for at least 15 years were recruited. These patients were annually followed for 2 years to assess overall outcome, psychiatric symptoms, rehospitalization, work, and social adjustment. A combination of medical record reviews and direct personal interviews with patients and family members provided the clinical data. RESULTS: Of these patients, 16.8% expressed a poor overall long-term outcome, even though only two (2.0%) patients exhibited alcohol dependence during the follow-up period. Multivariate regression showed that full compliance with medication was the strongest predictor of favorable overall long-term outcome, followed by younger age at onset and male sex. Younger age at onset as well as male sex, but not full compliance, also predicted a favorable psychosocial outcome. LIMITATIONS: Recruiting our sample from a clinical population with uncontrollable long-term treatment limits the generalizability of the findings. CONCLUSIONS: Compliance with pharmacotherapy is important to achieve a favorable overall long-term outcome of bipolar disorder. A portion of bipolar patients may have an unfavorable psychosocial outcome regardless of the psychopharmacological intervention or presence of substance abuse.

Adult↗
PubMed2001

Colorimetric assay for Lindane dechlorination by bacteria.

A colorimetric microtitre plate-based assay that detects haloalkane dehalogenase activity was modified to detect dechlorination of gamma-hexachlorocyclohexane (Lindane). Dechlorination is indicated by the colour change of phenol red from red to yellow, in a weakly buffered solution, as the solution becomes acidic due to HCl formed during dechlorination. Enzyme activity can be monitored by reading the absorbance of each well at 540 nm. Positive controls for the assay were the known Lindane-degrading microorganisms, Rhodanobacter lindaniclasticus and Sphingomonas paucimobilis UT26. Dechlorination in a scaled-up version of the assay was confirmed by GC/ECD detection of known metabolites of the test microorganisms from which the enzyme extracts were prepared. The assay was used to measure the rate of dechlorination in cell-free extracts of R. lindaniclasticus. It was also used to screen the cell-free extracts of 24 bacterial isolates, from a Lindane-contaminated soil, for Lindane dechlorination activity. Although no isolates tested positive, the assay represents a new inexpensive and rapid screening tool for the detection of Lindane-degrading microorganisms.

Bacteria↗
PubMed2001

Frizzled signaling and cell-cell interactions in planar polarity.

The function of the Frizzled pathway is essential for the formation of the array of distally pointing hairs found on the Drosophila wing. Previous research found that regulating the subcellular location for hair initiation controlled hair polarity. Recent work argues a graded Frizzled-dependent signal results in the accumulation of the Frizzled, Dishevelled and Flamingo proteins along the distal edge of the wing cells. This cortical mark leads to the local activation of downstream gene products and the subsequent activation of the cytoskeleton to form a hair.

Animals↗
PubMed2001

Toward a high-throughput approach to quantitative proteomic analysis: expression-dependent protein identification by mass spectrometry.

The isotope-coded affinity tag (ICAT) technology enables the concurrent identification and comparative quantitative analysis of proteins present in biological samples such as cell and tissue extracts and biological fluids by mass spectrometry. The initial implementation of this technology was based on microcapillary chromatography coupled on-line with electrospray ionization tandem mass spectrometry. This implementation lacked the ability to select proteins for identification based on their relative abundance and therefore to focus on differentially expressed proteins. In order to improve the sample throughput of this technology, we have developed a two-step approach that is focused on those proteins for which the abundance changes between samples: First, a new software program for the automated quantification of ICAT reagent labeled peptides analyzed by microcapillary electrospray ionization time-of-flight mass spectrometry determines those peptides that differ in their abundance and second, these peptides are identified by tandem mass spectrometry using an electrospray quadrupole time-of flight mass spectrometer and sequence database searching. Results from the application of this approach to the analysis of differentially expressed proteins secreted from nontumorigenic human prostate epithelial cells and metastatic cancerous human prostate epithelial cells are shown.

Autoanalysis↗
PubMed2001

Synthesis of ligand-specific phage-display ScFv against the herbicide picloram by direct cloning from hyperimmunized mouse.

Immunoglobulin genes were directly isolated from the splenocytes of a BALB/C mouse hyperimmunized with the auxinic herbicide picloram conjugated to bovine serum albumin. Variable light and heavy domain DNA were joined to produce single-chain Fv (scFv) DNA, which was cloned into phage vector fd-tet-GIIID to display multiple copies of scFv on the filamentous phage minor coat protein gIIIp. The phage-display scFv library (10(4) clones) was selected against picloram conjugated to ovalbumin. After five rounds of panning, individual clones were analyzed. ScFv with different affinities to picloram (IC(50) values ranging from 20 ppb to 10 ppm) were detected in the final enriched pool. The increased avidity of the phage vector enhanced the selection (i.e., panning) of multiple picloram-specific recombinant antibodies. Stringent selection was required to isolate the clones with the highest affinity. Nucleotide sequence analysis of six isolated clones revealed that all of the V(L) belonged to the V kappa 9A family joined to J kappa 2 segments. All of the V(H) belonged to the V(H)()7183 family and joined to two different J segments (i.e., J(H)()2 or J(H)()4). Different from the immune response to large molecular weight molecules (MW > 10,000 Da), which requires both VDJ segment rearrangement and somatic hypermutations, production of high-affinity antibodies to picloram, a small ligand having a formula weight of 241.5 Da, predominantly requires somatic hypermutations.

Animals↗
PubMed2001

Workplace tobacco policy: progress on a winding road.

This is a report of a pre- and post-intervention telephone survey to track changes in workplace tobacco policy in Pima County, Arizona, from 1997 to 1999. During this period, an extensive effort was made to assist workplaces to establish and enforce formal tobacco use policies. A random sample of 1134 workplaces, stratified by workforce size, was surveyed in 1997. Complete interviews were conducted with 934 (82.4%) workplaces. All 934 workplaces were contacted for the follow-up survey that was conducted in 1999. Of these, 824 (88.2%) completed follow-up surveys. The analyses presented were conducted on businesses that were included in both the baseline and follow-up surveys, and that reported having at least one employee on-site (n = 813). Tobacco policies and smoke-free policies were more likely to be found in larger businesses and businesses with a predominantly female workforce. There was no clear policy progression from having no policy, to having a policy, to becoming smoke-free. There was a small but significant overall decrease (4.8%) in the proportion of businesses having policies in the last two years. We found that 10.3% (75) of businesses that had policies in 1997 had dropped their policies by 1999, and that 13.4% (73) of worksites that were smoke-free in 1997 retained tobacco policies but were not smoke-free in 1999. However, formalization of policy in writing and the number of enforcement strategies utilized increased. These findings suggest that efforts to encourage businesses to establish workplace tobacco policies must be sustained even after policies have been established.

Arizona↗
PubMed2001

Open-reading-frame sequence tags (OSTs) support the existence of at least 17,300 genes in C. elegans.

The genome sequences of Caenorhabditis elegans, Drosophila melanogaster and Arabidopsis thaliana have been predicted to contain 19,000, 13,600 and 25,500 genes, respectively. Before this information can be fully used for evolutionary and functional studies, several issues need to be addressed. First, the gene number estimates obtained in silico and not yet supported by any experimental data need to be verified. For example, it seems biologically paradoxical that C. elegans would have 50% more genes than Drosophilia. Second, intron/exon predictions need to be tested experimentally. Third, complete sets of open reading frames (ORFs), or "ORFeomes," need to be cloned into various expression vectors. To address these issues simultaneously, we have designed and applied to C. elegans the following strategy. Predicted ORFs are amplified by PCR from a highly representative cDNA library using ORF-specific primers, cloned by Gateway recombination cloning and then sequenced to generate ORF sequence tags (OSTs) as a way to verify identity and splicing. In a sample (n=1,222) of the nearly 10,000 genes predicted ab initio (that is, for which no expressed sequence tag (EST) is available so far), at least 70% were verified by OSTs. We also observed that 27% of these experimentally confirmed genes have a structure different from that predicted by GeneFinder. We now have experimental evidence that supports the existence of at least 17,300 genes in C. elegans. Hence we suggest that gene counts based primarily on ESTs may underestimate the number of genes in human and in other organisms.

Animals↗
PubMed2001

HER-2 expression is a prognostic factor in patients with metastatic breast cancer treated with a combination of high-dose cyclophosphamide, mitoxantrone, paclitaxel and autologous blood stem cell support.

The expression levels of a circulating extracellular domain of HER-2 can be detected in the plasma and serum of patients with metastatic breast cancer using an enzyme immunoassay (ELISA) method. In this study, we evaluated the clinical significance of high and low levels of HER-2 in the plasma of 46 patients with metastatic breast cancer enrolled in a clinical trial of high-dose chemotherapy (HDCT) using cyclophosphamide, mitoxantrone, and paclitaxel with autologous stem cell transplantation (ASCT). Using 2500 U/ml as the cut-point, 20 patients (46%) had elevated HER-2 levels (HER-2 positive). Our results suggest that patients with metastatic breast cancer and high soluble plasma HER-2 have a significantly poorer overall (OS) and progression-free survival (PFS) following high-dose chemotherapy with paclitaxel and ASCT. The median OS of patients with low levels of HER-2 was significantly longer (P < 0.01) than the median OS of patients with high levels of HER-2 (29.8 months vs 15.9 months). PFS was also significantly longer (P < 0.01) for patients who were HER-2-negative, than for patients who were HER-2-positive (13.0 vs 8.6 months). Univariate analysis showed that patients with liver or lung metastases had significantly reduced OS and PFS. Patients with metastases to two or more sites also had a significantly reduced time to disease progression, but not OS. In multivariable analysis, lung metastases contributed along with HER-2-positive status to determine a group of patients with significantly poorer OS. However, HER-2-positive status remained the only independent predictor of PFS.

Adult↗
PubMed2001

Replicating adenoviral vector-mediated transfer of a heat-inducible double suicide gene for gene therapy.

Tumor cells that express a fusion gene of Escherichia coli cytosine deaminase (CD) and herpes simplex virus type 1 thymidine kinase (TK) sequences activate and are subsequently killed by the nontoxic prodrugs 5-fluorocytosine and ganciclovir. We have previously developed a recombinant adenovirus containing the CD-TK fusion gene controlled by the human inducible heat shock protein 70 promoter so that heat at 41 degrees C for 1 hour induces therapeutic gene expression. This adenovirus effectively transduces heat-inducible expression of the CD-TK gene into human prostate carcinoma cells. However, because a limited number of cells in a tumor can actually be infected, we created a replicating adenoviral vector to increase CD-TK gene expression. This vector is a replication-competent, E1B-attenuated adenoviral vector containing the hsp70 promoter-driven CD-TK gene (Ad.E1A(+)HS-CDTK). When human prostate adenocarcinoma DU-145 cells (mutant p53) were infected with the virus at a multiplicity of infection (MOI) of 1 or 10, the viral replication was detected within 2 days at both MOIs. Similar results were observed in human colorectal carcinoma CX-1 cells. When DU-145 cells were infected with the virus at an MOI of 10, incubated for 24 hours, heated at 41 degrees C for 4 hours, and then harvested 20 hours later, Western blot analysis demonstrated that this virus successfully produced viral E1A proteins and heat shock stimulated the CD-TK gene expression by 12.3-fold. In addition, Ad.E1A(+)HS-CDTK effectively suppressed cell proliferation by viral cytopathic effect). Unlike with a replication-incompetent virus (Ad.HS-CDTK), the cytopathic effect of the virus and cytotoxicity in the presence of the prodrugs were still observed even at low MOI (MOI=1.0).

Adenoviridae↗
PubMed2001

Efficient gene transfer of VSV-G pseudotyped retroviral vector to human brain tumor.

A retroviral vector constructed from the murine leukemia virus (MLV) can only express transgenes in cells undergoing mitosis, indicating its suitability as a delivery vehicle for cancer gene therapy. However, the transduction efficiency (TE) of retroviruses embedding endogenous envelope proteins in human cancer cells was found to be unsatisfactory. Recently, several research groups have demonstrated the feasibility of a retroviral vector pseudotyped with a vesicular stomatitis virus G (VSV-G) protein. In this study, the potential of VSV-G pseudotyped MLV-based retrovirus was examined as a delivery vehicle in a variety of human cancer cells including brain tumor cells in vitro and in vivo. The transduction efficiency of the 293T/G/GP/LacZ retrovirus in cell culture was superior in most cancer cells, particularly in brain tumor cells, compared with that of other retroviruses, such as PA317- or PG13-derived. The relative growth rate and phosphatidylserine expression level on the plasma membrane of target cells mainly influenced the transduction efficiency of VSV-G pseudotyped retrovirus, which suggested that both the relative growth rate and phosphatidylserine expression level were major determinants of TE. Furthermore, 293T/G/GP/LacZ could efficiently transduce human cancer cells regardless of the presence of chemical additives, whereas in other retroviruses, cationic chemical additives such as polybrene or liposomes were essential during virus infection. Finally, an average of 10% gene expression was routinely obtained exclusively in the tumor mass when 293T/G/GP/LacZ concentrated by simple ultracentrifugation was directly administrated to pre-established brain tumors in animal models (U251-N nu/nu mice or C6 Wistar rats). All told, the present study suggests that the VSV-G pseudotyped retrovirus is a suitable vector for brain tumor gene therapy.

Brain Neoplasms↗
PubMed2001

Phenotypic and genotypic characterization of Cryptosporidium species and isolates.

Recent outbreaks of cryptosporidiosis from contaminated water supplies have led to a need for the detection of Cryptosporidium oocysts from various hosts and contaminating sources. The presence of nonpathogenic species or strains of Cryptosporidium is important for diagnostic purposes as there is a potential for false- positive detection of pathogenic parasites. The present review focuses on phenotypic differences and recent advances in genotypic analyses of the genus Cryptosporidium with an emphasis on detecting various isolates and identifying differences in Cryptosporidium parvum and other species in this genus. The information currently available demonstrates important patterns in DNA sequences of Cryptosporidium, and our understanding of macro- and microevolutionary patterns has increased in recent years. However, current knowledge of Cryptosporidium genetic diversity is far from complete, and the large amount of both phenotypic and genotypic data has led to problems in our understanding of the systematics of this genus.

Animals↗
PubMed2001

Pigmentation in Koreans: study of the differences from caucasians in age, gender and seasonal variations.

BACKGROUND: Human skin colour shows variations throughout life, and many extrinsic and intrinsic factors influence melanogenesis. Facultative pigmentation of sun-exposed skin has been suggested to reflect cumulative lifetime ultraviolet (UV) exposure in caucasians. However, pigmentary changes due to various regulatory factors may be different in dark-skinned peoples. OBJECTIVES: To observe the variations in skin colour due to ageing, gender differences and seasonal changes in Koreans with skin type IV or V. METHODS: Skin pigmentation was measured at five body sites (buttock, glabella, the V of the neck area, inner arm and dorsal forearm) using skin reflectance spectroscopy in 497 subjects (age range 0-87 years) in winter and 311 subjects (age range 0-84 years) in summer. Among these subjects, 110 were assessed in both seasons. Three independent measurements at each site were done and the average value was used as the pigmentation level. RESULTS: Constitutive pigmentation of the buttock was highest in the first decade of life. It then decreased during the second decade and this decreased level was maintained after the third decade. In contrast to caucasians, facultative pigmentation and sun exposure index did not increase with ageing. Gender differences were significant at all body sites after the first decade. Seasonal changes were apparent in dorsal forearm pigmentation. Little difference was seen in forehead pigmentation between summer and winter. CONCLUSIONS: Basal melanogenic regulation might not be different between Asians and caucasians. However, the sun exposure index may not represent lifelong cumulative UV exposure in Koreans. Age-, gender- and season-related characteristics of skin pigmentation in Koreans imply that genetically determined basal skin colour plays an important part in characterizing later responsiveness to UV radiation and sex hormones. Understanding differences between races will be helpful in studying the regulatory mechanisms of melanogenesis.

Adolescent↗
PubMed2001

Evidence for direct involvement of beta-catenin in phorbol ester-induced neurite outgrowth in GT1-1 hypothalamic neurones.

Gonadotropin-releasing hormone (GnRH) is a pivotal neuroendocrine regulator controlling reproductive functions. However, the scattered distribution of GnRH neurones in the mammalian brain has hindered studies on the development and differentiation of GnRH neurones. In the present study, we used the immortalized GnRH-producing GT1-1 cells to examine whether activation of protein kinase C (PKC) pathway with 12-O-tetradecanoyl-13-acetate (TPA) induces morphological and functional differentiation of GnRH neurones. TPA induced neurite outgrowth and inhibited proliferation of GT1-1 cells that were specifically antagonized by cotreatment of PKC inhibitor, calphostin C. The functional significance of TPA-induced differentiation of GT1-1 cells was manifested in part by the changes in the effects of gamma-aminobutyric acid (GABA) on intracellular Ca2+ levels. In untreated GT1-1 cells, activation of GABA-A receptor with 10 microM muscimol increased intracellular Ca2+ levels, whereas such stimulatory effects disappeared in GT1-1 cells bearing neurites. Accordingly, muscimol could not stimulate GnRH release in TPA-treated GT1-1 cells. To elucidate the molecular mechanism underlying TPA-induced neurite outgrowth, we performed differential display reverse transcription-polymerase chain reaction. Among several genes that are affected by TPA treatment, we found a significant induction of beta-catenin mRNA expression. Along with the rapid induction of beta-catenin protein levels, we observed that beta-catenin was reallocated from cell-cell adhesion sites to the growth cones within 3 h of TPA treatment. Transient transfection studies with green fluorescent protein as a reporter gene demonstrated that beta-catenin overexpression alone can promote neurite outgrowth in GT1-1 cells. Moreover, TPA was found to increase the transcription-activational roles of beta-catenin. Together, these data provide evidence that beta-catenin is involved in the TPA-induced functional differentiation of immortalized GnRH neurones.

Calcium↗
PubMed2001

Resistance to the plant PR-5 protein osmotin in the model fungus Saccharomyces cerevisiae is mediated by the regulatory effects of SSD1 on cell wall composition.

The capacity of plants to counter the challenge of pathogenic fungal attack depends in part on the ability of plant defense proteins to overcome fungal resistance by being able to recognize and eradicate the invading fungi. Fungal genes that control resistance to plant defense proteins are therefore important determinants that define the range of fungi from which an induced defense protein can protect the plant. Resistance of the model fungus Saccharomyces cerevisiae to osmotin, a plant defense PR-5 protein, is strongly dependent on the natural polymorphism of the SSD1 gene. Expression of the SSD1-v allele afforded resistance to the antifungal protein. Conversely, yeast strains carrying the SSD1-d allele or a null ssd1Delta mutation displayed high sensitivity to osmotin. The SSD1-v protein mediates osmotin resistance in a cell wall-dependent manner. Deletion of SSD1-v or SSD1-d impeded sorting of the PIR proteins (osmotin-resistance factors) to the cell wall without affecting mRNA levels, indicating that SSD1 functions in post-transcriptional regulation of gene expression. The sensitivity of ssd1Delta cells to osmotin was only partially suppressed by over-accumulation of PIR proteins in the cell wall, suggesting an additional function for SSD1 in cell wall-mediated resistance. Accordingly, cells carrying a null ssd1 mutation also displayed aberrant cell-wall morphology and lower levels of alkali-insoluble cell-wall glucans. Therefore SSD1 is an important regulator of fungal cell-wall biogenesis and composition, including the deposition of PIR proteins which block the action of plant antifungal PR-5 proteins.

Alleles↗
PubMed2001

The Kasai portoenterostomy: when is it too late?

BACKGROUND/PURPOSE: Kasai portoenterostomy is recommended as the primary initial therapy for extrahepatic biliary atresia if the procedure can be performed within 10 to 12 weeks of life. The optimal management for infants with delayed presentation of biliary atresia remains controversial. The purpose of this study was to determine the success rate and outcome for patients who underwent a "late" Kasai portoenterostomy. METHODS: The authors conducted a retrospective review of the medical records of all patients with biliary atresia who underwent a Kasai portoenterostomy at their institution from 1986 to 1999 (n = 31). The authors analyzed success rates compared with age at the time of the Kasai procedure and the association with patient demographics. Surgical success was defined as achievement of a total serum bilirubin < or = 2 mg/dL. Long-term follow-up assessments included the need for liver transplantation and patient survival rate. RESULTS: The demographics of this study cohort showed a predominance of African-Americans, 19 of 31 (61%), and girls, 23 of 31 (74%). Assessment of success compared with subject age at the time of the initial portoenterostomy showed that 52% (13 of 25) had successful Kasai procedure at 0 to 75 days, compared with 83% success rate (5 of 6) at age 76 days or older (P = .359). Liver transplantation was performed in 16 of 31 patients (45%). Overall survival rate for the entire cohort is 23 of 31 (74%), whereas 12 of 31 (39%) are currently alive without a liver transplant. CONCLUSION: These data suggest that there is no contraindication to performing a Kasai portoenterostomy for biliary atresia in children over 75 days of age.

Age Factors↗