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Biomedical subjects

Y Lee

Publications and source records attributed to Y Lee.

At least 127 records · Page 7Linked to original sources
PubMed2001

Inhibition by clonidine of the carbachol-induced tension development and nonselective cationic current in guinea pig ileal myocytes.

Effects of clonidine, an imidazoline derivative as well as alpha2-adrenoceptor agonist, on carbachol (CCh)-evoked contraction in guinea pig ileal smooth muscle were studied using isometric tension recording. To investigate the cellular mechanisms of the inhibitory effect of clonidine, its effects on CCh-evoked nonselective cationic current (I(CCh)), voltage-dependent Ca2+ current (I(Ca)) and voltage-dependent K+ current (I(K)) was also studied using patch-clamp recording techniques in single ileal cells. Clonidine inhibited the contraction evoked by CCh (1 microM) in a concentration-dependent manner with an IC50 valve of 61.7 +/- 2.5 microM. High K+ (40 mM)-evoked contraction was only slightly inhibited even when clonidine was used at 300 microM. Externally applied clonidine inhibited I(CCh) dose-dependently with an IC50 of 42.0 +/- 2.6 microM. When applied internally via patch pipettes, clonidine was without effect. An I(CCh)-like current induced by GTPgammaS was also inhibited by bath application of clonidine. None of KU14R and BU224, both imidazoline receptor blockers, and yohimbine, an alpha2-adrenergic blocker, significantly affects the inhibitory effect of clonidine on I(CCh). Clonidine (300 microM) only slightly decreased membrane currents flowing through voltage-gated Ca2+ channels or K+ channels. These data indicate that clonidine relaxes smooth muscle contraction produced by muscarinic receptor activation and suggest that the effect of clonidine seems due mainly to inhibition of I(CCh) via acting directly on the involved cationic channel.

Adrenergic alpha-Agonists↗
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

Capsaicin-induced relaxation in rabbit coronary artery.

In the present study mechanism of inhibitory effects of capsaicin on the contractility of rabbit coronary artery were studied by measurement of isometric tension and intracellular Ca2+ concentration. Capsaicin (1 microM to 30 microM) relaxed the coronary artery pre-contracted with prostaglandin (PG) F2alpha (1 microM) in a concentration-dependent manner. The PGF2alpha-induced increase in intracellular Ca2+ concentration was also inhibited. The effects of capsaicin were readily reversed by washing capsaicin from the bath. Capsaicin-induced relaxation was not attenuated by pretreatment with capsazepine (1 microM), a blocker of vanilloid receptor or ruthenium red (1 microM), a blocker of non-selective cation channel. Previous exposure to a high concentration of capsaicin (100 microM) or repeated application of capsaicin did not eliminate the relaxation response to subsequent application of capsaicin. Increasing the external K+ concentration to 80 mM significantly attenuated the capsaicin-induced relaxation with simultaneous change in intracellular Ca2+ concentration. Pretreatment with iberiotoxin (100 nM), a blocker of Ca2+-activated K+ channel, only partially inhibited the capsaicin-induced relaxation. However, application of 4-aminopyridine (4-AP, 1 mM), a blocker of delayed rectifier K+ current significantly inhibited the capsaicin-induced relaxation with concomitant attenuation of the effect on intracellular Ca2+ concentration. These results indicate that capsaicin may have a direct relaxing effect on the smooth muscle contractility, and relaxation may be due to activation of the 4-AP-sensitive, delayed rectifier K+ channels in the rabbit coronary artery.

4-Aminopyridine↗
PubMed2001

Diet quality, nutrient intake, weight status, and feeding environments of girls meeting or exceeding recommendations for total dietary fat of the American Academy of Pediatrics.

OBJECTIVES: To compare the diet quality and weight status of girls consuming diets meeting the recommendation of the American Academy of Pediatrics for dietary fat with those of girls consuming >30% of energy from fat and to examine relationships between girls' dietary fat intake, mothers' nutrient intakes, and mothers' child-feeding practices. DESIGN: Participants were 192 white girls and their mothers, who were divided into 2 groups: >30% of energy from fat (high fat [HF]) or </=30% of energy from fat (low fat [LF]), based on girls' 3-day dietary recalls. Girls' food group and nutrient intakes, Healthy Eating Index, body mass index, and mothers' nutrient intakes and child-feeding practices were compared. RESULTS: Girls with HF diets consumed fewer fruits, more meat, and more fats and sweets and had lower Healthy Eating Index scores than did the girls in the LF group. Mothers of girls in the HF group had higher fat intakes than did those in the LF group. Girls and mothers in the HF group had lower intakes of fiber and vitamins A, C, B6, folate, and riboflavin. Mothers in the HF group reported using more restriction and pressure to eat in feeding their daughters. Girls in the HF group showed greater increase in body mass index and skinfold thickness from age 5 to 7 years. CONCLUSION: These findings provide additional support for the recommendation of the American Academy of Pediatrics to limit total dietary fat. Findings reveal that mothers' use of controlling feeding practices are not effective in fostering healthier diets among girls and that mothers' own eating may be more influential than their attempts to control the intake of their daughters. dietary fat, dietary quality, nutrient intake, overweight, feeding practices, children.

Academies and Institutes↗
PubMed2001

Application of time-of-flight secondary ion mass spectrometry to automobile paint analysis.

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) provides a method of elemental analysis that can distinguish among automotive paint samples of the same or nearly the same color. TOF-SIMS survey spectra were employed to determine the relative abundances of elements in the surface layers of the paint chips. The depth profile of paint samples permitted the analysis of small paint chips, the reproducible results for specific elements, and the identification of each car paint. Seventy-three samples of blue, red, white, and silver automobile paints from the major manufacturers in Korea were investigated using high resolution TOF-SIMS technique. It was found that paints of the same color produced by different manufacturers could be distinguished by this technique. TOF-SIMS is a reliable, nondestructive, and small area analyzing method for characterization of the elemental composition of automotive paint chips.

Journal Article↗
PubMed2001

Breast cancer and human immunodeficiency virus: a report of 20 cases.

Carcinoma of the breast is the most common malignancy in women in the United States. More than 40% of patients with human immunodeficiency virus (HIV) infection develop cancer during their illness, but breast cancer has seldom been reported. Twenty patients with breast cancer and HIV infection seen at the University of Miami/Jackson Memorial Hospital between January 1988 and August 2000 were retrospectively analyzed. Seventeen patients had a previous or concurrent diagnosis of HIV at the time of the breast cancer diagnosis. Their CD4 count ranged from 13-1126/microL (median, 309/microL). Most patients were premenopausal (16 of 20), with ages ranging from 31-61 years (median, 44 years). All stages of breast cancer were seen: ductal carcinoma in situ (2 patients), stage I (1 patient), stage II (9 patients), stage III (6 patients), and stage IV (2 patients). Ten tumors had estrogen receptors. Four of the 13 patients who underwent axillary lymph node dissection had abnormal lymph node findings, including 2 with follicular hyperplasia and 2 with caseating granulomas. Seven patients received chemotherapy with very poor tolerance. Estrogen receptor-positive patients were treated with tamoxifen. Of the 18 patients who presented with local disease, 7 have died: 2 of breast cancer, 4 of acquired immunodeficiency syndrome, and 1 of cardiac arrest. Nine patients remain free of disease (5 of them > 5 years) and 2 patients are alive with metastatic disease. Breast cancer in the HIV-positive population is similar to that seen in seronegative women. Most of the patients that are long-term survivors were treated with surgery and tamoxifen. The benefits of adjuvant chemotherapy are not clear.

Adult↗
PubMed2001

Predictors of readmission to a medical-psychiatric unit among patients with minor mental disorders.

BACKGROUND: Most studies on readmission have focused on patients with severe mental disorders such as schizophrenia and subjects were mostly collected in traditional psychiatric settings. This study investigated the predictors of readmission to a medical-psychiatric unit among patients with minor mental disorders in a general hospital. METHODS: All 164 patients admitted to a stress ward within a one-year period were recruited into this study. Data were retrospectively obtained by reviewing medical charts. Variables used to analyze and compare between patients who were and were not readmitted included patient characteristics, clinical features and multiple axes diagnoses of DSM-IV. RESULTS: Of 164 patients recruited, 135 were hospitalized only one time. The remaining 29 patients accounted for 61 admissions. The readmission rate was 17.7% (29/164). The significant predictors for readmission included Global Assessment of Functioning scores lower than 50 at admission, age under 40 years, previous psychiatric admission, alcohol dependence/abuse, dysthymia and comorbidity of borderline personality disorder. Using logistic regression to predict readmission within one year, we found the first four variables accurately differentiated 84.15% of patients who were readmitted from those who were not. CONCLUSIONS: Our results indicated the incidence of relapse in certain minor mental disorders is similar to that of severe mental disorders. By identifying predictors of readmission and intervening appropriately, unnecessary readmission may be prevented.

Adolescent↗
PubMed2001

Low dose fentanyl and propofol improve the speed and quality of tidal-breathing induction techniques in sevoflurane anesthesia for adults.

BACKGROUND: The objective of this study was to investigate whether low dose fentanyl, with or without low dose propofol, as pretreatment agent/s is capable of speeding up and improving the quality of laryngeal mask airway (LMA) insertion in tidal-breathing induction technique with high-concentration sevoflurane. METHODS: One hundred and twenty patients were assigned to one of the three groups: Group S, induction with 8% sevoflurane only; Group F + S, 1.0 microgram/kg fentanyl prior to induction; and Group F + P + S, 1.0 microgram/kg fentanyl and 0.5 mg/kg propofol prior to induction. RESULTS: It was demonstrated that the time from administration of drug (drugs) to loss of eyelash reflex (P < 0.05, Group F + P + S vs. F + S; P < 0.01, Group F + P + S vs. S), to jaw relaxation (P < 0.05, Group F + P + S vs. S) and time taken for LMA insertion (P < 0.01, Group F + P + S vs. S) were all shorter in Group F + P + S, with fewer complications (coughing and involuntary movement) during induction, however, the first time success rate with LMA insertion did not significantly differ among the comparing groups. According to a postoperative inquiry (by questionnaire), there were significantly more patients in the Group F + P + S (57.5%) who considered the induction as pleasant (P < 0.05), of whom 75% expressed that they would be willing to undergo an induction of the same form again in the future (P < 0.05). This more positive rating may be related to the mild sedative effects of the agents given and shorter induction time, which significantly helped reduce the rate of recall of the unpleasant gas. CONCLUSIONS: The results of this study of LMA insertion, for ASA I or II adult patients undergoing the tidal-breathing technique with 8% sevoflurane, suggest that pretreatment with 1 microgram/kg fentanyl plus 0.5 mg/kg propofol is superior in comparison with either pretreatment with 1 microgram/kg fentanyl or absence of pretreatment.

Adult↗
PubMed2001

Selection of a high-affinity DNA pool for a bZip protein with an out-of-phase alignment of the basic region relative to the leucine zipper.

bZip transcription factors contain two regions that are required for DNA binding: a leucine zipper dimerization domain and a highly charged basic region that directly contacts DNA. The spacing between these subdomains is strictly conserved, and changes in this spacing result in a loss of function. Using an in vitro selection strategy, we have investigated the ability of a bZip protein with incorrect spacing between these two regions to bind specifically to DNA. Surprisingly, we find that although such a protein does not bind to its predicted site, it is possible to isolate a pool of DNAs that bind with very similar affinity to that of GCN4 for its optimum DNA site.

Amino Acid Sequence↗
PubMed2001

Expression of beta-expansins is correlated with internodal elongation in deepwater rice.

Fourteen putative rice (Oryza sativa) beta-expansin genes, Os-EXPB1 through Os-EXPB14, were identified in the expressed sequence tag and genomic databases. The DNA and deduced amino acid sequences are highly conserved in all 14 beta-expansins. They have a series of conserved C (cysteine) residues in the N-terminal half of the protein, an HFD (histidine-phenylalanine-aspartate) motif in the central region, and a series of W (tryptophan) residues near the carboxyl terminus. Five beta-expansin genes are expressed in deepwater rice internodes, with especially high transcript levels in the growing region. Expression of four beta-expansin genes in the internode was induced by treatment with gibberellin and by wounding. The wound response resulted from excising stem sections or from piercing pinholes into the stem of intact plants. The level of wound-induced beta-expansin transcripts declined rapidly 5 h after cutting of stem sections. We conclude that the expression of beta-expansin genes is correlated with rapid elongation of deepwater rice internodes, it is induced by gibberellin and wounding, and wound-induced beta-expansin mRNA appears to turn over rapidly.

Adaptation, Physiological↗
PubMed2001

Investigation of the reaction pathway of OH radicals produced by Fenton oxidation in the conditions of wastewater treatment.

Abstract Fenton reaction has been often used to treat industrial wastewater or landfill leachate. However, most mechanistic research into the Fenton reaction has been confined to low concentration conditions (usually the concentration of iron is less than 1 mM). These conditions are removed from the circumstances of real application. This is especially true in the treatment of landfill leachate in Korea. Therefore, we investigated the characteristics of the Fenton system using high concentrations of iron (mostly [Fe2+] = 1 approximately 10 mM, [H2O2] = 5 mM, [Organic (t-BuOH or methanol)] = 0 or 30 mM) and interpreted the results from the known reaction mechanisms of the Fenton system. As a result, the use of high ferrous ion (> or = 1 mM) is believed to be appropriate for producing large quantities of OH. within a short period of time, causing fast consumption of hydrogen peroxide. However, OH. scavenging by the ferrous ion, the changes of oxidation products due to the oxygen depleted conditions, and the precipitation effect of ferric ion must be considered for the successful application of Fenton reaction. On the other hand, in low ferrous ion (<1 mM), it is important to utilize the redox cycles of iron in an effective manner.

Chemical Precipitation↗
PubMed2001

A phase I and pharmacological study of the farnesyl protein transferase inhibitor L-778,123 in patients with solid malignancies.

This Phase I study was performed to assess the feasibility of administering L-778,123, a peptidomimetic farnesyl protein transferase (FPTase) inhibitor, as a continuous i.v. infusion for 7 days every 3 weeks and to determine the recommended dose for subsequent disease-directed trials. This study also sought to characterize the pharmacological behavior of L-778,123 and to determine whether the desired biological effect, inhibition of protein farnesylation, could be detected and assessed during treatment. Patients with advanced solid malignancies were treated with L-778,123 as a continuous i.v. infusion for 7 days every 3 weeks at doses ranging from 35 to 1120 mg/m(2)/day. On the basis of preclinical studies, toxicity assessments included cardiac telemetry, electrocardiograms, and electroretinograms in addition to more routine safety monitoring laboratory tests. Plasma sampling was performed to characterize the pharmacokinetics of L-778,123, and peripheral blood mononuclear cells (PBMCs) were sampled to detect and monitor the inhibitory effects of L-778,123 on the prenylation of HDJ2, a chaperone protein that undergoes farnesylation. Twenty-five patients received 51 complete courses of L-778,123. An unacceptably high incidence of dose-limiting toxicities, consisting of grade 4 thrombocytopenia, significant prolongation of the QT(c) interval, and profound fatigue, was observed at the 1120 mg/m(2)/day dose level. At the next lower L-778,123 dose level, 560 mg/m(2)/day, seven new patients had no unacceptable toxicity. Instead, myelosuppression was mild to moderate and QT(c) prolongation was negligible. Pharmacokinetics were linear, and L-778,123 plasma concentrations at steady-state (mean, 8.09 +/- 3.11 microM at 560 mg/m(2)/day) exceeded IC(50) values (range, 0.07-5.35 microM) required for growth inhibition and cytotoxicity in preclinical studies. The systemic clearance of L-778,123 averaged 106.4 +/- 45.6 ml/min/m(2), and the terminal half-life of elimination was 2.8 +/- 1.0 h. L-778,123 inhibited HDJ2 prenylation for the duration of the drug infusion in a dose-dependent manner, but seemed to plateau above 560 mg/m(2)/day. At the 560 mg/m(2)/day dose level, the mean percentage of HDJ2 protein in its unprenylated form increased from 1.41% +/- 1.71% (pretreatment) to 28.76% +/- 6.10% (day 4) and 30.86 +/- 4.96 (day 8) and declined to 2.28% +/- 2.11% one week after drug discontinuation (day 16). L-778,123 administered as a continuous 7-day i.v. infusion for 7 days every 21 days is well tolerated at doses of 560 mg/m(2)/day and results in biologically relevant concentrations and consistent inhibition of HDJ2 prenylation in PBMCs. Although the relationship between drug-related inhibition of HDJ2 prenylation in PBMCs and both prenylation of relevant proteins and growth inhibition in tumor cells is unknown, serial analyses of HDJ2 prenylation provide a pharmacodynamic marker of protein prenylation that may be useful in optimizing the development of drugs targeting FPTase.

Adult↗
PubMed2001

Prevention of PONV with dexamethasone in female patients undergoing desflurane anesthesia for thyroidectomy.

BACKGROUND: Desflurane is associated with a higher incidence of 24-h postoperative nausea and vomiting (PONV) as compared with sevoflurane or isoflurane. Dexamethasone 5 mg i.v. is suggested to be the minimum effective dose for prophylaxis of PONV in women undergoing thyroidectomy with isoflurane anesthesia. The objective of this study was to investigate whether a 5 mg dose of dexamethasone could be enough for, or a larger dose at 8 mg, could be more capable of preventing PONV in women undergoing desflurane anesthesia for thyroidectomy. METHODS: One hundred and thirty five patients were assigned to receive one of three treatment regimens prior to induction i.e., dexamethasone 8 mg i.v. (Group D8), dexamethesone 5 mg i.v. (Group D5) or saline (Group S). RESULTS: It was demonstrated that the prophylactic administration of either dexamethasone 8 mg or 5 mg significantly reduced the overall incidence of PONV in patients undergoing thyroidectomy with desflurane anesthesia (P < 0.001, Group D8 vs. Group S; Group D5 vs. Group S). However, patients who received dexamethasone 8 mg showed a higher incidence of complete responses (no vomiting or need of rescue antiemetic medication for a 24-h postoperative period) in comparison with those receiving dexamethasone 5 mg (86% vs. 67%; P < 0.01). CONCLUSIONS: The results of this study showed that in PONV prophylaxis, in female patients undergoing desflurane anesthesia for thyroidectomy, the effect of dexamethasone 8 mg was superior to that of dexamethasone 5 mg.

Adult↗
PubMed2001

Melatonin ameliorates autoimmune encephalomyelitis through suppression of intercellular adhesion molecule-1.

Melatonin (N-acetyl-5-methoxytryptamine), a pineal neurohormone, is a hydroxyl radical scavenger and antioxidant, and plays an important role in the immune system. We studied the effect of exogenous melatonin on the pathogenesis of experimental autoimmune encephalomyelitis (EAE). EAE was induced in Lewis rats by immunization with rat spinal cord homogenates. Subsequent oral administration of melatonin at 5 mg/kg significantly reduced the clinical severity of EAE paralysis compared with administration of the vehicle alone (p<0.01). Infiltration of ED1+ macrophages and CD4+ T cells into spinal cords occurred both in the absence and presence of melatonin treatment, but melatonin-treated rats had less spinal cord infiltration of inflammatory cells than did the control group. ICAM-1 immunoreactivity in the blood vessels of EAE lesions was decreased in melatonin-treated rats compared to vehicle-treated rats. These findings suggest that exogenous melatonin ameliorates EAE via a mechanism involving reduced expression of ICAM-1 and lymphocyte function associated antigen-1a in autoimmune target organs.

Animals↗
PubMed2001

Application of pulsed Doppler ultrasound for the evaluation of small intestinal motility in dogs.

The purpose of this study was to verify whether small intestinal peristalsis could be observed and quantitatively assessed using pulsed-Doppler ultrasound. Pulsed-Doppler ultrasound was used to evaluate small intestinal peristalsis after a meal in ten normal dogs and ten sedated dogs. The small intestinal peristalses were measured 0, 1, 3, 6, 9, 12, and 24 hours after a 24-hour fast and after feeding. The number of small intestinal peristalsis were 0.133/min, 0.100/min, 0.033/min, 0.167/min, 0.070/min, 0.067/min, and 0.100/min in the fasted dogs, and 1.667/ min, 0.933/min, 1.133/min, 1.234/min, 1.933/min, 1.533/ min, and 0.533/min in fed dogs, respectively. In the dogs sedated with xylazine HCl, the number of small intestinal peristalsis was significantly reduced (p<0.01). However, in the dogs treated with ketamine HCl and acepromazine, the number of small intestinal peristalsis remained unchanged. Therefore, it can be concluded that pulsed-Doppler ultrasound allows graphic visualization of the intestinal movements, which can be subjected to qualitative and quantitative analysis, and may be suitable for a non-invasive study of small intestinal motility.

Acepromazine↗
PubMed2000

Slow recovery of body fat lost during adenovirus-induced hyperleptinemia.

In normal rats, adenovirus-induced hyperleptinemia causes disappearance of visible body fat, downregulation of lipogenic enzymes, and upregulation of oxidative enzymes and thermogenic proteins. In addition, preadipocyte markers replace mature adipocyte markers, suggesting dedifferentiation. In weight loss induced by caloric restriction, by contrast, the lipogenic machinery is essentially intact. To determine if the radical changes induced by leptin would slow the reappearance of body fat, we compared normal lean rats made hyperleptinemic by infusing an adenovirus-leptin construct with diet-matched littermates. Initially, in plasma leptin the hyperleptinemic rats averaged approximately 50x the controls and, although it declined progressively, it was still slightly elevated at 150 days (P < 0.05). In the hyperleptinemics, body fat mass, quantified by magnetic resonance spectroscopy, remained below the pretreatment value for 60 days, while in diet-matched controls it exceeded the pretreatment value. Epididymal fat pad weight in hyperleptinemics was still 28% below paired controls at 150 days posttreatment. Histologic examination revealed adipocytes of hyperleptinemic animals to be smaller 60 days after treatment. At 60 days, adipose tissue UCP-2 gene expression in hyperleptinemics was still above controls, but expression of other lipogenic and oxidative enzymes had returned to baseline expression levels. We conclude that in normal rats recovery of body fat following adenovirus-induced hyperleptinemia is much slower than after caloric restriction, possibly because of persistent upregulation of adipocyte UCP-2.

Adenoviridae↗
PubMed2000

An intronless gene encoding a poly(A) polymerase is specifically expressed in testis.

Previous work demonstrated that a single pre-mRNA could generate multiple forms of mammalian poly(A) polymerase mRNAs by alternative splicing or alternative polyadenylation. A cDNA encoding a testis-specific poly(A) polymerase was isolated in this study. The transcription level of Papt in testis of a 2 weeks old mouse was much lower than that of the general poly(A) polymerase gene, Pap. However, the transcription ratio of Papt to Pap was reversed in testis of a 4 weeks old mouse. Transient expression analysis showed that GFP-Papt fusion protein is present both in the nucleus and cytoplasm of HeLa cells. These results suggest that Papt is involved in polyadenylation of transcripts expressed during spermatogenesis.

Alternative Splicing↗