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Biomedical subjects

M H Lee

Publications and source records attributed to M H Lee.

At least 37 records · Page 2Linked to original sources
PubMed2004

Effect and putative mechanism of action of ginseng on the formation of glycated hemoglobin in vitro.

As a non-enzymatic, covalent binding between glucose and protein, glycation is a well-known cause of various forms of diabetic complications. This study was undertaken to determine the effect and mechanism of action of ginseng on the formation of glycated protein. A solution containing hemoglobin and glucose was incubated for 5 days by adding ginseng extract or glutathione. The quantitative measurement of glycated hemoglobin was determined using the ion capture component set. The anti-oxidative effect of ginseng and quercetin was determined through the TBA method. The amount of glycated hemoglobin (%GHb) significantly increased with the addition of glucose (27.8 mM) compared to the non-addition group. Nonetheless, this significantly decreased when ginseng extract (2 g/dl) was added and further dropped when glutathione (50 mM) was added. The amount of hemoglobin A1c (%HbA1c), a sub-fraction of glycated hemoglobin, was lower than that of glycated hemoglobin, but it showed a similar tendency. Compared to a non-addition group, the optical density of the organic layer that was separated through the addition of chloroform in oxidized linoleic acid significantly and dose-dependently decreased when ginseng extract or quercetin was added. These results suggest that the inhibitory effect of ginseng on the formation of glycated hemoglobin could be attributed to the anti-oxidative activity of ginseng.

Antioxidants↗
PubMed2004

Magnetic resonance imaging of metaplastic carcinoma of the breast: sonographic and pathologic correlation.

Metaplastic carcinoma of the breast is a rare disease. We describe the MRI findings with the correlative sonographic and pathologic features of two cases. On MRI, T2-weighted images demonstrate a relatively well-defined mass with high signal intensity cystic components. Dynamic enhancement subtraction images showed an early enhancing and delayed washout peripheral rim and non-enhancing internal components. A microlobulated, isoechogenic mass with cystic components was seen sonographically, and was histopathology related to necrosis and cystic degeneration. Although these features are not unique, metaplastic carcinoma should be included in the differential diagnosis for breast masses.

Adult↗
PubMed2004

Autoantibodies to glucose-6-phosphate isomerase are elevated in the synovial fluid of rheumatoid arthritis patients.

OBJECTIVE: This study investigated whether anti-glucose-6-phosphate isomerase (GPI) antibody in the synovial fluid is specifically related to human rheumatoid arthritis (RA). METHODS: Synovial fluid was collected from patients with RA, osteoarthritis (OA), gout, Behcet's disease, or ankylosing spondylitis. GPI-binding activity was measured in the synovial fluid using a surface plasmon resonance (SPR) biosensor. RESULTS: The mean level of anti-GPI signal in the synovial fluid of RA patients was significantly elevated compared with that of OA patients (2.84 +/- 1.41 AU versus 1.19 +/- 0.42 AU, respectively; p < 0.0001). Anti-GPI signals in the synovial fluids of patients with non-rheumatoid arthritis, such as gout, Behcet's disease, or ankylosing spondylitis were significantly lower than in the synovial fluid of RA patients (p < 0.005), and were similar to those of OA patients. CONCLUSION: Our study indicates that anti-GPI antibody in the synovial fluid is specifically related to RA, and suggests that GPI and its autoantibody might be important in the pathogenesis of human RA.

Adult↗
PubMed2004

Subtypes of alpha1- and alpha2-adrenoceptors mediating noradrenergic modulation of spontaneous inhibitory postsynaptic currents in the hypothalamic paraventricular nucleus.

Noradrenergic inputs to the hypothalamic paraventricular nucleus (PVN) play important roles in the regulation of neuroendocrine and autonomic functions. Previous reports show that noradrenaline increases the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) in a subpopulation of type II neurones, acting via alpha(1)-adrenoceptors (ARs), but reduces this frequency in most type I and another subpopulation of type II neurones, via alpha(2)-ARs on presynaptic GABA neurones. Here, we identified the subtypes of alpha-ARs mediating noradrenaline-induced increases and decreases in the sIPSC frequency of PVN neurones, by using slice patch recordings from PVN neurones. In both type I and II neurones, the noradrenaline-induced decrease in sIPSC frequency was completely blocked by BRL44408 (alpha(2A)-AR antagonist) at 1-3 micro M, which is approximately 1/100 of its equilibrium dissociation constant (pA(2) = 8.0), but not by prazosin (20-100 micro M, alpha(2B/C)-AR antagonist; pA(2) = 7.5). The effect of noradrenaline was mimicked by guanfacine (alpha(2A)-AR agonist) with an EC(50) of 0.1 micro M. In type II neurones, the noradrenaline-induced increase in sIPSC frequency was not blocked by any of the following antagonists: RS17053 (10 micro M, alpha(1A)-AR antagonist), BMY7378 (2 micro M, alpha(1D)-AR antagonist), prazosin (0.1 micro M, alpha(1)-AR antagonist; pA(2) = 10.5), or chloroethylclonidine (10 micro M, alpha(1B/D)-AR antagonist). However, the effect of noradrenaline was blocked by higher concentrations of prazosin (1 micro M) or RS17053 (100 micro M), suggesting the involvement of alpha(1L)-subtype, a low affinity form of alpha(1A)-ARs. Collectively, our results indicate that the alpha(2A)-, or alpha(1L)-ARs on the GABA neurones mediate the noradrenaline-induced decreases, or increases in the frequencies of the sIPSCs of PVN neurones, respectively.

Adrenergic alpha-Agonists↗
PubMed2004

Role of C-terminal heptapeptide in pore-forming activity of antimicrobial agent, gaegurin 4.

Gaegurin 4 (GGN4) is an antimicrobial peptide of 37 amino acids isolated from the skin of a frog, Rana rugosa. GGN4 has a disulfide bond between the residues 31 and 37, which is highly conserved among the antimicrobial peptides isolated from skin of the genus, Rana. However, the role of this C-terminal heptapeptide motif is not well understood. In this work, we compared the membrane effects of the full-length GGN4 (C37) and GGN4 1-30 (C30), which is devoid of the C-terminal seven amino acids to elucidate the function of the C-terminal motif. C37 induced significantly larger membrane conductance (>10x) in the model lipid bilayers formed with acidic and neutral phospholipids and larger K+ efflux from gram-positive (>30x) and gram-negative bacteria. However, the pores induced by C37 and C30 were not different in their permeability to K+ over Cl- (permeability ratio of K+ to Cl- = 4.8-7.1). In addition, the pore-forming effect of C37 or C30 in acidic membranes was not different from that in neutral membranes. Furthermore, C37-induced K+ efflux was not significantly decreased by the reducing agent, dithiothreitol. The results indicate that C-terminal heptapeptide sequence plays an important role in maintaining the high pore-forming activity of GGN4, but does not participate in forming GGN4-induced pore structure. The disulfide bond in this region does not appear critical for such high ionophoric activity of GGN4.

Amino Acid Motifs↗
PubMed2004

Capecitabine monotherapy in patients with anthracycline- and taxane-pretreated metastatic breast cancer.

The selection of chemotherapeutic regimens is challenging for metastatic breast cancer (MBC) patients whose diseases have failed to respond to anthracyline and taxane. Capecitabine has advantages of oral administration and favorable toxicity profiles. This study was conducted to evaluate the efficacy of capecitabine and to identify the subgroup of patients who would potentially have benefit from capecitabine monotherapy in patients with anthracycline- and taxane-pretreated MBC. Female patients with MBC who had been previously treated with anthracycline and taxane received oral capecitabine 2500 mg/m(2) divided in two doses daily for 2 wk with 1-wk rest period. Between September, 1999, and December, 2002, a total of 38 patients were enrolled. Among the 36 evaluable patients, one patient achieved a complete response (CR), 9 patients had partial responses (PRs), and 13 patients had stable diseases (SDs). Response rate was 26% [95% confidence interval (CI), 12-40%] and the tumor control rate (TCR, CR+PR+SD) was 61% (95% CI, 45-77%). The median follow-up duration was 27.8 mo. The median duration of response was 8.9 mo, the median time to progression was 4.6 mo, and the median overall survival was 18.1 mo. The major toxicities were hand-foot syndrome, diarrhea, and emesis. There was no treatment-related death. The predictors of better overall survival were positivity of hormone receptor, disease-free survival longer than 1 yr, non-refractoriness to anthracycline, and fewer number (<or= 3) of involved organs. Capecitabine monotherapy is effective and well tolerated for MBC patients who had previously been treated with anthracycline and taxane. The TCR could predict overall survival as well as the objective response in this study, suggesting a possible role of TCR as a surrogate marker for survival in MBC patients on salvage chemotherapy. The patients who have relatively slow growing tumor and less tumor burden could have benefit from capecitabine monotherapy following anthracycline- and taxane-based chemotherapy.

Administration, Oral↗
PubMed2003

Autologous peripheral blood stem cell transplantation with induction of autologous graft-versus-host disease in acute myeloid leukemia.

We studied whether the induction of autologous graft-versus-host disease (GVHD) has an antileukemic effect and consequently increases the survival of patients undergoing autologous peripheral blood stem cell transplantation (PBSCT). In all, 22 acute myeloid leukemia patients with favorable and intermediate cytogenetic risk, in their first complete remission, were administered cyclosporine c.i.v. from day 0 to day +28 at a dose of 3.0 mg/kg per day and interferon-gamma (IFN-gamma) at 0.025 mg/m(2) s.c. every other day from day +14 to day +42 following autologous PBSCT. Natural-killer (NK)-cell activity assays and skin biopsies were performed. Successful engraftment was achieved in all patients at a median of 13 days without significant additional toxicity. Histologically confirmed cutaneous GVHD developed in 12 patients, and NK-cell activity was significantly augmented after autologous PBSCT in those patients (P=0.03). After a median follow-up duration of 37.7 months (range, 7.3-72.8), the 3-year disease-free survival (DFS) and overall survival (OS) rates were 64.4 and 73.1%, respectively, without significant correlation with GVHD status or augmentation of NK-cell activity. These data suggest that the administration of cyclosporine and IFN-gamma following autologous PBSCT improves OS and DFS, which may be attributable to the antileukemic effect, although no difference in survival could be demonstrated between cutaneous GVHD-positive and -negative groups.

Acute Disease↗
PubMed2003

Inhibition of monoamine oxidase B (MAO-B) by Chinese herbal medicines.

Monoamine oxidase (MAO) catalyzes the oxidative deamination of biogenic amines accompaned by the release of H2O2. Two subtypes, MAO-A and MAO-B, exist on the basis of their specificities to substrates and inhibitors. The regulation of MAO-B activity is important in the treatment of neurodegenerative diseases. Twenty-seven species of plants used in traditional Chinese medicines, selected from an enthnobotanical survey, were used in an investigation of their inhibitory effect on MAO-B in rat brain homogenates. The 50% aqueous methanol extracts of four active extracts, Arisaema amurense, Lilium brownii var. colchesteri, Lycium chinense, and Uncaria rhynchophylla, exhibited the best activity and selectivity towards MAO-B with IC50 values of 0.44, 0.29, 0.40, and 0.03 mg/ml, respectively. A kinetic study of MAO-B inhibition by the four extracts using the Lineweaver-Burk plot for each active extract revealed the IC50 concentrations, and results show that: Ki = 0.59 mg/ml for A. amurense for the mixed-type mode, Ki = 0.58 mg/ml for L. brownii var. colchesteri for the mixed-type mode, Ki = 5.01 mg/ml for L. chinense for the uncompetitive mode, and Ki = 0.02 mg/ml for U. rhynchophylla for the uncompetitive mode. These may therefore be candidates for use in delaying the progressive degeneration caused by neurological diseases.

Animals↗
PubMed2003

Free radical-scavenging activity of Taiwanese native plants.

The 70% aqueous acetone extracts of ten Taiwanese native plants were evaluated by various antioxidant assays, including 1, 1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl (.OH) radicals, and reducing power assay. In the present study, extracts of Acer buerferianum var. formosanum, Cleyera japonica var. morii, Cyclobalanopsis stenophylla var. stenophylloides, and Machilus zuihoensis exhibited stronger activity against DPPH radicals, and their IC50 values ranged from 5.4 to 8.3 microg/ml. The ten selected extracts effectively inhibited the formation of .OH generated in the Fenton reaction system. Among the extracts whose reducing power activities were determined, A. buerferianum var. formosanum, C. japonica var. morii, C. stenophylla var. stenophylloides, Eriobotrya deflex, and M. zuihoensis showed high activity. The results indicate the 70% aqueous acetone extracts of A. buerferianum var. formosanum, C. japonica var. morii, C. stenophylla var. stenophylloides, and M. zuihoensis with great potency in these assay systems and may be candidates for the development of natural antioxidants.

Acer↗
PubMed2003

Postoperative chemoradiotherapy for gastric cancer.

BACKGROUND: We report the results of postoperative chemoradiotherapy after curative resection in gastric cancer patients. PATIENTS AND METHODS: Patients with gastric cancer staged IB to IV(M0) were treated with chemoradiotherapy after curative resection with extensive (D2) lymph node dissection. Nodal metastases were observed in 261 (90%) patients. The chemotherapy consisted of fluorouracil 400 mg/m(2) plus leucovorin 20 mg/m(2) for 5 days, followed by 4500 cGy of radiotherapy for 5 weeks with fluorouracil and leucovorin on the first 4 days and the last 3 days of radiotherapy. Two 5-day cycles of chemotherapy were given 4 weeks after the completion of radiotherapy. RESULTS: Of 290 patients accrued, 229 (79%) patients completed chemoradiotherapy as planned. With a median follow-up of 49 months, 114 (34%) patients have relapsed: 33 (29%) locoregional relapses, 76 (67%) peritoneal relapses and 41 (36%) distant metastases. The 5-year overall and relapse-free survivals were 60% and 57%, respectively. Tolerance was acceptable, the main toxicity being neutropenia. CONCLUSIONS: This postoperative chemoradiotherapy after curative resection of gastric cancer was feasible, with acceptable toxicities. Whether this adjuvant therapy in gastric cancer patients that have undergone a D2 lymph node dissection impacts on survival or reduces the incidence of relapses remains to be studied.

Adenocarcinoma↗
PubMed2002

Prenatal diagnosis of a familial complex chromosomal rearrangement involving chromosomes 5, 10, 16 and 18.

We report one case of a familial complex chromosomal rearrangement (CCR) involving four different chromosomes 5, 10, 16 and 18. The CCR was detected prenatally at 20 weeks' gestation because of advanced maternal age and history of recurrent miscarriages. Cytogenetic analysis of cultured amniotic fluid cells with GTG banding showed a 46,XX,t(5;16;10;18)(q13;q22;q11.2;q21) karyotype. Parental cytogenetic study revealed that the mother has the same CCR. RBG banding, high resolution banding and fluorescence in situ hybridization (FISH) were used to characterize further and confirm the conventional banding data. No physical abnormalities were shown in the targeted fetal ultrasonography examination. The parents decided to continue the pregnancy. The child is now 2 years old and has neither congenital anomalies nor evidence of delayed psychomotor development. The fetal targeted ultrasound and FISH analysis helped us reassure fetal status.

Abortion, Habitual↗
PubMed2002

Clinical features of peripheral T-cell lymphomas in 78 patients diagnosed according to the Revised European-American lymphoma (REAL) classification.

The aim of this study was to analyse the clinical characteristics and prognostic factors of peripheral T-cell lymphomas (PTCLs) according to the Revised European-American Lymphoma (REAL) classification. From 1994 to 1999, 78 patients were diagnosed with PTCLs, excluding cutaneous T-cell lymphomas and T-cell chronic lymphocytic leukaemia. The distribution of the histological subgroups were: PTCL unspecified (PTCL-U), 40%; angiocentric lymphoma, 32%; anaplastic large cell lymphoma (ALCL), 17%; angioimmunoblastic T-cell lymphoma (AILD), 6%; intestinal T-cell lymphoma, 3%; and panniculitic T-cell lymphoma, 3%. Patients with angiocentric lymphoma presented with favourable prognostic factors, whereas those with AILD presented with unfavourable prognostic factors. Most patients were treated with doxorubicin-containing combination chemotherapy (with or without radiation therapy). The overall complete remission rate was 61.2% (95% Confidence Interval (CI): 48.5-72.8%) and the 5-year probability of failure-free survival was 33.5%. Median survival of all patients was 45 months (range 0-64+ months) and the 5-year probability of survival was 36.2%. In the multivariate analysis, only the International Prognosis Index (IPI) was an independent prognostic factor for overall survival (P<0.01). Taken together, the proportion of angiocentric lymphoma in this study was higher than that in the studies of Western countries. PTCL responds poorly to treatment with low survival rates and the IPI is a useful prognostic factor for PTCL.

Adolescent↗
PubMed2002

Measurement of 90sr in aqueous samples using liquid scintillation counting with full spectrum DPM method.

90Sr activity was measured with the full spectrum DPM (FS-DPM) counting method after plotting the quench correction curves of 90Sr and 90Y, and the FS-DPM method was applied to determine the 90Sr in liquid waste samples. The optimum regions of 90Sr and 90Y were set for measuring 90Sr with the dual label DPM (DL-DPM) method. The direct measurement of purified 90Sr with spectrum unfolding techniques could overcome the disadvantages of the DL-DPM method. The activities of 90Sr in the 90Sr/90Y standardized solution measured with the FS-DPM protocols were close to the true activity. The concentrations of 90Sr in the liquid waste samples measured with the FS-DPM counting method were compared with those obtained with conventional methods.

Journal Article↗
PubMed2002

A study on the prevalence of and risk factors for neck pain among university academic staff in Hong Kong.

The 1-year prevalence of neck pain and possible risk factors among university academic staff were investigated. Self-administered questionnaires were distributed to all the full-time academic staff in one of the universities in Hong Kong. The 1-year prevalence of neck pain was investigated. The relationship between individual factors, job nature, psychosocial factors, and neck pain were also analyzed. The 1-year prevalence of neck pain among after being an academic staff was 46.7%. A significant association was found between gender and neck pain (p = 0.02). The percentage of female academic staff with neck pain (62%) was higher than that in male staff (38%). This matched the results of other studies, which demonstrated that neck pain was more prevalent in women. There was a significant association between head posture during computer processing and neck pain (p = 0.02). Among those with neck pain during computer processing, 60.5% had a forward head posture. However, a low correlation between psychosocial factors and neck pain was demonstrated (r = 0.343). Academic staff in tertiary institutions could be considered as a high-risk group of job-related neck pain.

Adult↗
PubMed2002

Enhancement of 1 alpha,25-dihydroxyvitamin D(3)-induced differentiation of human leukaemia HL-60 cells into monocytes by parthenolide via inhibition of NF-kappa B activity.

1. Transcription factors such as NF-kappa B provide powerful targets for drugs to use in the treatment of cancer. In this report parthenolide (PT), a sesquiterpene lactone of herbal remedies such as feverfew (Tanacetum parthenium) with NF-kappa B inhibitory activity, markedly increased the degree of human leukaemia HL-60 cell differentiation when simultaneously combined with 5 nM 1 alpha,25-dihydroxyvitamin D(3) (1,25-(OH)(2)D(3)). PT by itself did not induce HL-60 cell differentiation. 2. Cytofluorometric analysis indicated that PT stimulated 1,25-(OH)(2)D(3)-induced differentiation of HL-60 cells predominantly into monocytes. 3. Pretreatment of HL-60 cells with PT before the 1,25-(OH)(2)D(3) addition also potentiated the 1,25-(OH)(2)D(3)-induced HL-60 cell differentiation in both a dose- and a time-dependent manner, in which the enhanced levels of cell differentiation closely correlated with the inhibitory levels of NF-kappa B binding activity by PT. 4. In contrast, santonin, a sesquiterpene lactone without an inhibitory activity of NF-kappa B binding to the kappa B sites, did not enhance the 1,25-(OH)(2)D(3)-induced HL-60 cell differentiation. 5. In transfection experiments, PT enhanced 1,25-(OH)(2)D(3)-induced VDRE-dependent promoter activity. Furthermore, PT restored 1,25-(OH)(2)D(3)-induced VDRE-dependent promoter activity inhibited by TNF-alpha, an activator of NF-kappa B signalling pathway. 6. These results indicate that PT strongly potentiates the 1,25-(OH)(2)D(3)-induced HL-60 cell differentiation into monocytes via the inhibition of NF-kappa B activity and provide evidence that inhibition of NF-kappa B activation can be a pre-requisite to the efficient entry of promyelocytic leukaemia cells into a differentiation pathway.

Cell Differentiation↗
PubMed2002

A randomized trial of heparin plus ursodiol vs. heparin alone to prevent hepatic veno-occlusive disease after hematopoietic stem cell transplantation.

Hepatic veno-occlusive disease (VOD) is a common and serious regimen-related toxicity after hematopoietic stem cell transplantation (HSCT). There is no safe and proven therapy for established VOD, and focus has been on its prevention. Previous studies have shown that a continuous infusion of unfractionated heparin or ursodiol may reduce the incidence of VOD. In order to compare the efficacy of heparin plus ursodiol with that of heparin alone, we conducted a prospective, randomized study involving 165 consecutive patients who underwent HSCT for a variety of disorders. Eighty-two patients were assigned to receive heparin plus ursodiol, and 83 were assigned to receive heparin alone. Thirteen and 16 patients were diagnosed as having VOD in the heparin plus ursodiol group and the heparin alone group, respectively (15.9% vs 19.3%; P = 0.348). Eighty-nine percent of the heparin plus ursodiol group and 89.2% of the heparin alone group were surviving at day 100 post-HSCT (P = 0.298). The only independent variable associated with an increased risk of VOD was an allogeneic type of HSCT (P = 0.018). In conclusion, this study shows that there is no difference in efficacy between heparin plus ursodiol and heparin alone for the prevention of hepatic VOD.

Adult↗
PubMed2002

Polymorphisms of tumour necrosis factors A and B in breast cancer.

We assayed for germline single nucleotide polymorphisms (SNPs) in the TNFB and TNFA genes in patients with breast cancer. SNPs were observed in the first intron of TNFB (G/A) and at -1031 (T/C), -863 (C/A), -857 (C/T) and -308 (G/A) in the promoter region of TNFA from peripheral leucocytes in 95 breast cancer patients and 190 healthy subjects as controls. The TNFB*G/TNFB*G homozygote (23.2% vs. 5.8%, P= 0.001) was predominant in patients, while the TNFB*A/TNFB*A homozygote was less frequent in patients (34.7% vs. 46.3%, P = 0.041) than in the control subjects. Breast cancer was not associated with SNPs in the TNFA promoters. Although the TNFB SNP failed to associate with any clinicopathological parameter of breast cancer, a substantial difference in pathology among tumour stages for the -857 SNP in TNFA was detected. These results indicate that TNFB has both tumorigenic and antitumorigenic capabilities depending on the genotype: the TNFB SNP TNFB*G/TNFB*G genotype gave an increased risk for breast cancer and that of TNFB*A/TNFB*A gave resistance to breast cancer (OR = 5.3395%; CI: 2.33-12.19). The results suggest that the TNFB*G allele plays some role in the tumorigenesis or activation of dormant tumour cells, but the TNFB*A allele induces some function(s) leading to the inhibition of tumorigenesis.

Adult↗