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Biomedical subjects

K Lee

Publications and source records attributed to K Lee.

At least 181 records · Page 10Linked to original sources
PubMed2001

Evaluation of efficiency of screening extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in hospitals where the bacteria are increasingly prevalent.

The disk screening methods for extended-spectrum beta-lactamase-producing strains were evaluated. The confirmatory work is reduced significantly in settings such as those in this study, by changing the cefpodoxime breakpoint to < or =20 mm and by not testing cefoxitin-resistant isolates. Cefotaxime and ceftazidime disk screening is reliable, and the laboratory-prepared cefotaxime- and ceftazidime-clavulanic acid disks are stable at -20 degrees C for 12 weeks.

Anti-Bacterial Agents↗
PubMed2001

Partner notification in HIV-1 infection: a population based evaluation of process and outcomes in Scotland.

OBJECTIVES: To evaluate the process and outcomes of HIV partner notification (PN) activity in Scotland. DESIGN: Retrospective population based study. SUBJECTS: 114 adults newly diagnosed with HIV infection (index patients) in Scotland between September 1995 and August 1996. SETTING: Healthcare settings in which all 114 new HIV diagnoses were made: 42 (37%) from genitourinary medicine; 32 (28%) infectious diseases; 18 (16%) general practice; and 22 (19%) from other sites. MAIN OUTCOME MEASURES: Number of partners notified and tested up to 9 months after initial diagnosis. RESULTS: Of 114 index patients (IPs), information on current partners was available for 102 (89%). PN was not appropriate for 47 of the 102 IPs. The remaining 55 IPs identified 63 current partners at risk, of whom 51 were notified: 44 underwent HIV testing, which yielded 11 new HIV positive diagnoses. Information on previous partners was available for only 56 IPs (49%). PN was not appropriate for 30 of the 56 IPs; the remaining 26 IPs identified 46 previous partners at risk, of whom 12 were notified: four were tested, but yielded no new diagnoses. CONCLUSIONS: Notification of current partners was performed well and was an effective strategy for identification of HIV positive individuals at a presymptomatic stage. Notification of previous partners was limited. Partner notification was attempted in a wide range of healthcare settings. Given the clinical effectiveness of antiretroviral therapy, partner notification as a tool towards early diagnosis of HIV disease deserves renewed attention.

Adult↗
PubMed2001

Upregulation of transcription factors in lung in the early phase of postpneumonectomy lung growth.

In the adult rodent, pneumonectomy results in compensatory lung growth characterized by cell proliferation. The molecular mechanisms governing this response remain unknown. We hypothesized that, in the early period postpneumonectomy, upregulated expression of transcription factors drives the growth process. We utilized a cDNA expression array to screen for upregulated transcription factors after left pneumonectomy in adult C57BL/6 mice, using unoperated mice as controls. Quantification of mRNA expression in the remaining lung at 2 h demonstrated a twofold or greater upregulation of six transcription factors: early growth response gene-1 (Egr-1), Nurr77, tristetraprolin, the primary inhibitor of nuclear factor-kappa B (I kappa B-alpha), gut-enriched Krüppel-like factor (GKLF), and LRG-21. Northern analysis was used to quantify the upregulation of expression of these genes relative to sham thoracotomy and unoperated controls. The largest increase was in Egr-1 (4.7-fold > naive). Time-course analysis over the first 24 h confirmed the transient nature of the early upregulation. In the context that postpneumonectomy lung growth is associated with cell proliferation and that genes such as Egr-1, Nurr77, LRG-21, and tristetraprolin have known roles in stress response, vascular biology, embryology, and cellular development, these data support the concept that transcription factors function early in the cascade of events leading to the compensatory response.

Animals↗
PubMed2001

Previously undetected human hematopoietic cell populations with short-term repopulating activity selectively engraft NOD/SCID-beta2 microglobulin-null mice.

Increasing use of purified or cultured human hematopoietic cells as transplants has revealed an urgent need for better methods to predict the speed and durability of their engraftment potential. We now show that NOD/SCID-beta2 microglobulin-null (NOD/SCID-beta2m-/-) mice are sequentially engrafted by two distinct and previously unrecognized populations of transplantable human short-term repopulating hematopoietic cells (STRCs), neither of which efficiently engraft NOD/SCID mice. One is predominantly CD34+CD38+ and is myeloid-restricted; the other is predominantly CD34+CD38- and has broader lymphomyeloid differentiation potential. In contrast, the long-term repopulating human cells that generate lymphoid and myeloid progeny in NOD/SCID mice engraft and self-renew in NOD/SCID-beta2m-/- mice equally efficiently. In short-term expansion cultures of adult bone marrow cells, myeloid-restricted STRCs were preferentially amplified (greater than tenfold) and, interestingly, both types of STRC were found to be selectively elevated in mobilized peripheral blood harvests. These results suggest an enhanced sensitivity of STRCs to natural killer cell-mediated rejection. They also provide new in vivo assays for different types of human STRC that may help to predict the engraftment potential of clinical transplants and facilitate future investigation of early stages of human hematopoietic stem cell differentiation.

Animals↗
PubMed2001

Cardiac surgical patients exposed to heparin-bonded circuits develop less postoperative cerebral dysfunction than patients exposed to non-heparin-bonded circuits.

A prospective randomized trial was used to study the incidence of cerebral dysfunction in patients undergoing cardiopulmonary bypass (CPB) with heparin-bonded vs non-heparin-bonded circuits. Although the etiology of postoperative cerebral dysfunction is controversial, activation of the systemic inflammatory response may play a role. After institutional approval and informed written consent, 39 elective coronary artery bypass (CABG) patients were studied. A battery of neuropsychometric tests (NPMTs) was performed preoperatively, and 5 days and 6 weeks postoperatively. Significant change in NPMT performance was defined as a 25% or greater decrease in postoperative performance, compared to baseline. The number of abnormal tests per patient was calculated. Analysis using the Mann-Whitney rank test was performed for the first follow-up. Patients randomized to heparin-bonded circuits had fewer abnormal NPMTs (>1 abnormal test) on postoperative day 5 (58 vs 70%, n=19 and 20) than patients randomized to non-heparin-bonded circuits. Patients exposed to heparin-bonded circuits had fewer abnormal tests (>1 abnormal test) at 6 weeks (36 vs 63%, n=14 and 16). Results suggested that the attenuation of systemic inflammation by heparin-bonded CPB circuits may lower the incidence of cerebral injury in cardiac surgical patients.

Cardiopulmonary Bypass↗
PubMed2001

Longitudinal study of health maintenance organization efficiency.

Longitudinal studies looking at health maintenance organization (HMO) efficiency in the United States have not been performed before this study--previously there have only been small inter-group studies comparing efficiencies. The objectives here were twofold: to analyse HMO efficiency longitudinally, using a data envelopment analysis (DEA) model; and to compare the various types of HMOs and their efficiency using DEA. A cohort of HMOs was followed longitudinally and a number of variables measuring efficiency were studied. Data were derived from the HMO database survey (HCIA Inc.) for 1993-1997. Thirty-six HMOs were followed over a five-year period, and baseline input and output variables were collected. These measures are proxies for efficiency using the DEA methodology. Over all, using the DEA model it was demonstrated that HMOs tended to improve efficiency over time. Independent Practice Association HMOs appeared to show the highest level of improved efficiency. HMO type, profit status, federal eligibility and age were predictive variables for efficiency. Results of this study demonstrate that HMOs are improving efficiency longitudinally, and in general, certain specific models are longitudinally more efficient than others. Moreover, attributes of efficient HMOs have been identified. For policy-makers looking at efficiency, this information can be used to determine which HMO models are more appropriate when trying to achieve cost containment and effectiveness.

Benchmarking↗
PubMed2001

Electrophysiologic and antiarrhythmic effects of the new class III antiarrhythmic drug KCB-328 in experimental canine atrial flutter.

BACKGROUND: The electrophysiologic and antiarrhythmic effects of a new class III antiarrhythmic drug (KCB-328), a delayed rectifier potassium current (IKr) blocker with minimal reverse use-dependent effect on atrial repolarization, were evaluated in the canine night atrial crush-injury model of atrial flutter (AFL). METHODS: Ten anesthetized, open-chest dogs, were studied after right atrial crush-injury. Atrial effective refractory period (ERP), conduction velocity (CV), wavelength, and dispersion of refractoriness were determined during programmed stimulation (S1S2 at S1S1 = 200, 300, 400, and 500 msec) at four sites via a mapping plaque sutured on the right atrial free wall. Right and left ventricular ERP were similarly measured at single sites. Electrophysiological parameters were determined at baseline and following sequential cumulative doses of KCB-328 (10, 30, 100, and 300 microg/kg). RESULTS: Sustained AFL was inducible in 7/10 dogs by rapid pacing following baseline electrophysiologic measurements. KCB-328 significantly prolonged sinus cycle length, but had no effect on PR interval, and prolonged QTc only at the highest dose level. KCB-328 significantly prolonged atrial ERP and wavelength and ventricular ERP, and significantly reduced dispersion of atrial refractoriness. KCB-328 significantly prolonged AFL cycle length, and increasing doses progressively terminated sustained AFL and prevented its reinduction by pacing. No adverse hemodynamic or ventricular proarrhythmic effects were observed. CONCLUSIONS: The electrophysiologic profile of KCB-328 in this canine model of AFL, particularly its lack of reverse use-dependent effect on atrial refractoriness, suggests that it may have significant antiarrhythmic potential in treatment of atrial arrhythmias.

Animals↗
PubMed2001

Interdisciplinary education in a community-based geriatric evaluation clinic.

BACKGROUND: Demographic predictions are challenging schools of medicine to emphasize geriatrics. This article describes a geriatric evaluation (GET) clinic and explores the opportunity for residents to attain core geriatric competencies. DESCRIPTION: The GET clinic is located in a small Midwestern city associated with a community-based medical school. It is staffed by an interdisciplinary team consisting of a geriatrician, a gerontological nurse specialist, and a social worker. Residents, medical students, and nursing students are frequent participants. EVALUATION: Descriptive data indicate that the clinic experience addresses the core competencies set forth by the American Geriatric Society. The clinical outcomes indicate that the clinic is effective in maintaining the functional status of patients and has a positive effect on family caregivers. Residents and students rate their experience as excellent. CONCLUSIONS: The GET clinic provides a unique interdisciplinary educational opportunity. Further investigation is needed to determine if residents who participate do attain core competencies.

Aged↗
PubMed2001

LH induces orphan nuclear receptor Nur77 gene expression in testicular Leydig cells.

The orphan nuclear receptor Nur77 (NR4A1) is a member of the nuclear receptor superfamily and plays an important role in the regulation of genes involved in steroidogenesis and cell death. Northern blot analysis revealed that the expression of Nur77 mRNA was increased after puberty in mouse testis, and hCG treatment of peripubertal animals induced this gene expression in the testis. Moreover, LH treatment induced a transient increase in Nur77 mRNA, and this induction was LH dose dependent in mouse Leydig tumor cell line, K28. Western blot analysis showed that LH transiently induced Nur77 protein. The protein kinase inhibitor H-89, bisindolymaleimide I, and wortmannin strongly inhibited this inductive effect of LH on Nur77 gene expression. Transient transfection assay demonstrated that LH significantly increased the Nur77 promoter-driven luciferase reporter activity in a dose-dependent manner, and LH also increased the activity of a luciferase reporter gene driven by a promoter containing multi copies of a Nur77-responsive element. Moreover, EMSA showed that Nur77 DNA-binding activity was increased in response to LH. Finally, overexpression of dominant negative Nur77 reduced LH-mediated progesterone biosynthesis. Taken together, these results demonstrate that LH induces Nur77 gene expression, and Nur77 may play an important role in the LH-mediated steroidogenesis in Leydig cells.

Animals↗
PubMed2001

Gonadotropin regulation of NGFI-B messenger ribonucleic acid expression during ovarian follicle development in the rat.

NGFI-B is an immediate-early gene that encodes an orphan nuclear receptor. The present study was designed to examine the localization and gonadotropin regulation of NGFI-B expression in the rat ovary. Northern blot analysis of ovaries obtained from prepubertal rats revealed the increased expression of NGFI-B during prepubertal development. Treatment of immature rats with PMSG, however, decreased ovarian NGFI-B expression. The major cell types expressing NGFI-B messenger RNA were thecal cells of follicles in different sizes. In contrast, treatment of PMSG-primed rats with human (h) CG resulted in the rapid and transient stimulation of ovarian NGFI-B messenger RNA, reaching a peak within 1 h. In situ hybridization analysis revealed that hCG treatment induced the expression of NGFI-B in granulosa cells of preovulatory follicles. Treatment of cultured preovulatory follicles in vitro with LH further confirmed the time- and dose-dependent stimulation of NGFI-B messenger RNA and protein. LH-stimulated NGFI-B expression in preovulatory follicles was abolished by alpha-amanitin, but was superinduced by cycloheximide. Furthermore, treatment of adult cycling rats with pentobarbital abolished NGFI-B expression on proestrus, and exogenous administration of hCG restored it, indicating the role of the preovulatory surge of LH in the stimulation of NGFI-B expression. These results demonstrate the cell type-specific expression and gonadotropin induction of NGFI-B in granulosa cells of preovulatory follicles and suggest a role for NGFI-B in the ovulatory process.

Animals↗
PubMed2001

Stage-dependent regulation of ovarian pituitary adenylate cyclase-activating polypeptide mRNA levels by GnRH in cultured rat granulosa cells.

The present study was designed to test whether GnRH regulates pituitary adenylate cyclase-activating polypeptide mRNA levels in a stage-dependent manner during follicle development in the rat ovary. The granulosa cells of preovulatory and immature follicles obtained from PMSG- and estrogen-treated rats, respectively, were cultured in serum-free conditions in the presence of various hormones. GnRH receptor mRNA expression was detected in both preovulatory and immature granulosa cells and was down-regulated by gonadotropins. Treatment of preovulatory granulosa cells with GnRH agonist stimulated pituitary adenylate cyclase-activating polypeptide mRNA levels in a dose-dependent manner. In situ hybridization analysis of cultured preovulatory follicles revealed that GnRH-induced pituitary adenylate cyclase- activating polypeptide signals were detected in granulosa cells, but not thecal cells. In immature granulosa cells, cotreatment with GnRH agonist suppressed FSH-stimulated pituitary adenylate cyclase-activating polypeptide mRNA levels in a dose-dependent manner, whereas treatment with GnRH alone had no effect. Furthermore, treatment with GnRH antagonist inhibited LH-induced pituitary adenylate cyclase-activating polypeptide gene expression in preovulatory granulosa cells, whereas it stimulated FSH-induced pituitary adenylate cyclase-activating polypeptide gene expression in immature granulosa cells. Interestingly, GnRH-stimulated pituitary adenylate cyclase-activating polypeptide mRNA levels in preovulatory granulosa cells was inhibited by arachidonyltri fluoromethyl ketone, an inhibitor of phospholipase A(2), but not by an inhibitor of protein kinase A or C. Lastly, treatment of preovulatory follicles with pituitary adenylate cyclase-activating polypeptide antagonist suppressed GnRH-stimulated progesterone production during 6--9 h of culture. Taken together, these results demonstrate the stage-dependent regulation of pituitary adenylate cyclase-activating polypeptide mRNA levels by GnRH, the stimulatory and inhibitory effect in granulosa cells of preovulatory and immature follicles, respectively.

Animals↗
PubMed2001

A bioactive spirolactone iridoid and triterpenoids from Himatanthus sucuuba.

Himatanthus sucuuba is an Amazonian tree with abundant, yet conflicting ethnobotanical information. Investigation of the polar and non-polar constituents led to the isolation of plumericin, a bioactive spirolactone iridoid, and four known pentacylic triterpenes: lupeol acetate, lupeol cinnamate, lupeol beta-phenyl propionate, and alpha-amyrin cinnamate.

3T3 Cells↗
PubMed2001

Effect of dopamine on excretory urographic image quality and the prevention of contrast-induced nephropathy in dogs.

The effect of low dose dopamine on the excretory urographic image quality and contrast media-induced nephropathy in normal dogs (experiment 1) and the dogs with decreased renal function (experiment 2) were assessed. In experiment 2, decreased renal function was induced by gentamicin overdose. In each experiment, animals were divided into 3 groups. In group 1, only contrast medium (iohexol) was administered. In group 2, contrast medium plus intravenous fluid (0.9% saline) were administered. And in group 3, contrast medium plus intravenous fluid and low dose dopamine were administered. Investigated parameters included intrarenal resistive index (RI), serum BUN and creatinine concentrations, contrast medium elimination time and radiographic image quality. In experiment 1, RI of group I increased at 80 min after contrast medium administration (p<0.05), but RI of group 3 decreased at 48 and 72 hr (p<0.05). Serum BUN concentration of group 1 was higher than that of group 2 and 3 (p<0.05); in radiographic examination, contrast medium elimination time decreased in group 2 and 3, but image quality of group 2 was inferior to that of group 3. In experiment 2, image quality of group 3 only provided adequate visualization of renal structures. The formula of contrast medium plus low dose dopamine was found to provide good nephrogram and pyelogram image quality without supplemental contrast medium, and to protect renal tubules from prolonged exposure to concentrated contrast medium.

Animals↗
PubMed2001

Molecular analysis of defect healing in rat diaphyseal bone.

Spatial expression of messenger ribonucleic acid (mRNA) for osteoblastic marker in drill hole defect healing of adult male rats was analyzed by in situ hybridization. The defect was filled with hematoma 3 days after surgery, expressing Type I collagen mRNA. Hematoma was replaced with fibrous tissue on day 7, and then with new trabecular bone on day 10, originated from the intra-medullary space, respectively. mRNA for Type I collagen, parathyroid hormone 1 receptor (PTHIR), and alkaline phosphatase (ALP) were expressed in the same cell population of fibrous tissue adjacent to newly-formed trabecular bone, and in osteoblasts lining the newly-formed trabecular bone. Hematopoietic marrow with osteoclasts subsequently invaded the region, also from the intra-medullary space, replacing all the new trabecular bone by day 21, except for a thin sub-periosteal layer. mRNA for Type I collagen, PTH1R and ALP was expressed on the periosteal surface of thin layer. Although cartilage formation was not histologically visible, mRNA for Type II collagen was weakly detected in the majority of osteoblasts lining the newly-formed trabecular bone.

Alkaline Phosphatase↗
PubMed2001

Effects of combining public assistance and employment on mothers and their young children.

One goal of recent welfare reform legislation is to move welfare-dependent mothers with young children into the paid labor force. However, prior to the new legislation, many welfare-dependent women were already engaged in employment activities. In this paper we examine whether child or maternal well-being is influenced by a mother's strategy of combining work and public assistance receipt in the late 1980s. Measures of well-being include children's cognitive test scores and behavior problems, parenting behavior, and maternal mental health, social support, and coping strategies collected when children were 2 1/2 to 3 years of age. Data from the Infant Health and Development Program (a sample of low birthweight, premature infants born in 8 sites in 1985) were used to identify low-income families (incomes under 200% of the poverty threshold; N = 525). Comparisons were made among mothers in the following groups: (a) Work Only, (b) Some Work-Some Welfare, (c) Some Work-No Welfare, (d) No Work-No Welfare, and (e) Welfare Only. Mothers in the Some Work-Some Welfare group had children with cognitive and behavioral scores similar to children whose mothers were in the Work Only group; these two groups also had similar mental health, social support, and coping scores. However, not working and receiving welfare (Welfare Only) was associated with negative cognitive and behavioral outcomes for children, with less stimulating home learning environments, lower maternal mental health, less social support, and more avoidant coping strategies. We discuss the proposition that welfare and work may be complementary rather than opposing strategies, in terms of putting together a family income package.

Adaptation, Psychological↗
PubMed2001

'They all look alike to me': prejudice and cross-race face recognition.

We investigated whether prejudice level influences the size of the other-race effect (poorer recognition of other-race compared with own-race faces). Previous studies, using self-report measures of prejudice, failed to find a relationship between prejudice and the other-race effect. We used an implicit prejudice measure, developed by Fazio, Jackson, Dunton, and Williams (1995), to determine whether implicit prejudice influences the size of the other-race effect. A self-report measure of prejudice, Walker's (1994) Attitudes to Asians Scale, was also included to replicate previous results. A group of 30 high prejudice and 30 low prejudice Caucasian participants, as determined by the self-report measure, were run through a procedure which assesses implicit prejudice and recognition performance at the same time. Neither implicit nor self-reported prejudice level influenced the size of the other-race effect. Unexpectedly, implicit and self-report prejudice influenced (in opposite ways) recognition of own-race faces. The implications of these results for understanding the other-race effect are discussed.

Adolescent↗
PubMed2001

Antimicrobial resistance surveillance of bacteria in 1999 in Korea with a special reference to resistance of enterococci to vancomycin and gram-negative bacilli to third generation cephalosporin, imipenem, and fluoroquinolone.

The trend of antimicrobial resistance of bacteria isolated from patients in 30 Korean hospitals in 1999 was analyzed with a particular attention to cefotaxime- or fluoroquinolone-resistant gram-negative bacilli, imipenem-resistant Pseudomonas aeruginosa, and vancomycin-resistant enterococci. Adequacy of susceptibility testing, and any change in the frequencies of isolated species were also analyzed. The results showed that only 20% and 30% of hospitals tested the piperacillin-tazobactam and cefoxitin susceptibility of Enterobacteriaceae, respectively, only 24% of hospitals the piperacillin-tazobactam susceptibility of P. aeruginosa, and 17% of hospitals the fusidic acid susceptibility of staphylococci. Among the isolates 26.3% were glucose-nonfermenting gram-negative bacilli, and 34.7% of Enterococcus were Enterococcus faecium. Slight decline of cefotaxime-resistance rate to 20% was noted in Klebsiella pneumoniae, while fluoroquinolone-resistance rate was 68% in Acinetobacter baumannii. The ceftazidime- and imipenem-resistance rates were 17% and 18%, respectively in P. aeruginosa. The vancomycin-resistance rate of E. faecium rose significantly to 15.1%, but the rates varied significantly depending on hospitals suggesting presence of different degree of selective pressure or nosocomial spread. In conclusion, the prevalence of imipenem-resistant P. aeruginosa and the increase of vancomycin-resistant E. faecium were the particularly worrisome phenomena observed in this study.

Anti-Bacterial Agents↗