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Biomedical subjects

H P Wu

Publications and source records attributed to H P Wu.

At least 19 recordsLinked to original sources
PubMed2006

Wurtzite-to-rocksalt structural transformation in nanocrystalline CoO.

Hexagonal CoO nanocrystals are coarsened under hydrothermal conditions to investigate the effect of particle size on phase transformation and stability property. Structural stability and phase transformation of the hexagonal CoO phase have been investigated by X-ray powder diffraction with Rietveld refinement, transmission electron microscopy, X-ray absorption fine structure, and differential scanning calorimeter. It is found that the hexagonal CoO phase is a metastable phase, which increases its grain size from 50 to 250 nm for refluxing times from 1 to 6 h at 200 degrees C. After 12 h, cubic-structured CoO grains with an average grain size of 20 nm are observed, which spread around big hexagonal CoO grains. After about 24 h, only the cubic CoO phase with an average grain size of 25 nm is detected. The onset temperature of hexagonal-to-cubic phase transformation in CoO is estimated to be 378 degrees C by DSC, using a heating rate of 20 deg/min. The results obtained indicate that the hexagonal-to-cubic phase transformation in nanocrystalline CoO is by nucleation and growth mechanism, starting from the surface to the center of the hexagonal grains.

Journal Article↗
PubMed2006

Double-blind, randomized, multicentre study of the efficacy and safety of gliclazide-modified release in the treatment of Chinese type 2 diabetic patients.

BACKGROUND AND AIM: Gliclazide-modified release (gliclazide MR) is a new formulation of the sulfonylurea gliclazide designed for once-daily administration. The hydrophilic matrix of hypromellose-based polymer in the new formulation induces a progressive drug release, which parallels the 24-h glycaemic profile in type 2 diabetic patients. The aim of this study was to compare the efficacy and safety of gliclazide MR (once-daily administration) versus gliclazide (twice-daily administration) in Chinese type 2 diabetic patients. MATERIALS AND METHODS: Sixty-three type 2 diabetic Chinese patients who had been on diet control alone or on treatment with metformin or on low dose of sulfonylurea were randomized to either gliclazide MR taken once daily or gliclazide taken twice daily. Dosage of metformin was maintained throughout the study, and the sulfonylurea was stopped. The dose of gliclazide MR was increased at 1-month intervals from 30 mg to 120 mg, while that of gliclazide from 80 mg to 320 mg until metabolic control was achieved [fasting plasma glucose (FPG) < or = 7.7 mmol/l] or the maximum dose reached. Efficacy was mainly evaluated by levels of haemoglobin A1c (HbA1c) and FPG. RESULTS: The mean baseline characteristics of the full analysis set 1 (FAS1) (HbA1c, n = 58) and the FAS2 (FPG, n = 61) were comparable in both groups. The levels of HbA1c decreased similarly in both groups over the treatment period: -1.6 +/- 1.6% (p < 0.001) on gliclazide MR (n = 31) and -1.6 +/- 1.4% (p < 0.001) on gliclazide (n = 27). Decrease in HbA1c was observed irrespective of pre-existing therapy for diabetes: -2.3 +/- 1.5% for patients on diet alone; -0.6 +/- 1.3% for patients switched from sulfonylurea to study drug and -1.4 +/- 0.8% for patients on metformin in combination with study drug. FPG decreased significantly from 177.5 +/- 63.5 to 136.7 +/- 42.2 (p < 0.001, n = 32) on gliclazide MR and not significant from 188.2 +/- 62.6 to 163.7 +/- 67.9 (p = 0.059, n = 29) on gliclazide. Both treatments were very well tolerated with no major hypoglycaemic episodes requiring external assistance; only three patients experienced mild hypoglycaemic episodes. CONCLUSIONS: Once-daily gliclazide MR showed a better trend in improving blood glucose control in comparison with gliclazide in type 2 diabetic Chinese patients irrespective of the pre-existing anti-diabetic treatment. The safety profiles of gliclazide MR and gliclazide were similar with a small number of patients having reported hypoglycaemic episodes. Once-daily dosing with gliclazide MR should improve patient compliance, an important factor in long-term glycaemic control.

Adult↗
PubMed2001

Highly selective formation of [4+2] and [4+3] cycloadducts of tetrahydroindenes generated in situ from a (1-alkynyl)carbene tungsten complex by the metalla-1,3,5-hexatriene route.

1-Amino-3-ethoxytetrahydro-3aH-indenes 8 can be readily generated together with pentacarbonyl(pyridine)tungsten in a template induced three-component reaction of [(1-cyclohexenyl)ethynyl]carbene tungsten complex 1 with secondary amines 2a-d and pyridine. Even though the compounds 8 are thermally quite unstable and undergo a fast rearrangement to tetrahydro-7aH-indenes 7. they can be trapped by formation of (rather strained) [4+2] cycloadducts 12 with maleimide 11. If 1-amino-3-ethoxytetrahydro-3aH-indenes 8 are generated in the presence of electron-poor alkynes 2a and 2b, they undergo a 1,5-shift to give tetrahydro-7aH-indenes 7, which in turn afford [4+2] cycloadducts 4a-d. Condensation of 1-tungsta-1,3,5-hexatrienes (3E)-5a-d with 1-metalla-1,3-butadienes 14 (M = Cr, W) give [4+3] cycloadducts 15a-e of tetrahydro-7aH-indenes 7 in good yields with high regio- and stereoselectivity.

Journal Article↗
PubMed2001

"Dimers" and "trimers" of tetrahydroindenes and hexahydroazulenes, respectively generated from [2-(1-cycloalkenyl)ethynyl]carbene complexes (M = W, Cr) by cascade cyclization/cycloaddition reactions.

A cascade of cyclization/cycloaddition reactions was triggered by addition of protic oxygen nucleophiles ROH 2 (RO = CH3CO2, PhCO2, PhO) to [2-(1-cyclohexenyl)ethynyl]carbene complexes 1b and 1c (M=W, Cr, respectively), affording highly strained "dimers" 11/11' and "trimers" 12 of the carbene ligand. The first reaction step involved the formation of 1-metalla1,3,5-hexatrienes 7, which readily gave tetrahydroindenes 8 by pi cyclization and extrusion of the metal unit. "Dimers" 11/11' were generated from tetrahydroindenes 8 by a highly exo selective [4+2] cycloaddition of compounds 1b and 1c to afford 1-metalla-1,3,5-hexatriene intermediates 9, and a spontaneous pi cyclization of the latter compounds involving the disengagement of the metal unit. Propenylidene cyclohexenes 13/13' were formed in "ene"-type side reactions to the pi cyclization of 1-metalla-1,3,5-hexatrienes 7, by loss of the metal unit. "Dimers" 11 were transformed into "trimers" 12 by a [4+2] cycloaddition and subsequent pi-cyclization of the resulting 1-metalla-1,3,5-hexatriene system. The course of the reaction was elucidated by means of model reactions with (2-phenylethynyl)carbene complex 14, in which 1-metalla-1,3,5-hexatriene intermediates 16 and 17 were isolated and characterized. Alkynyl benzene derivatives 19 were obtained by an unprecedented ring-expansion of a cyclopentadiene unit of "dimers" 11a and 11c, involving the insertion of a carbene carbon atom of compound 14 into a C=C bond. A reaction cascade leading to "dimers" 24/24' could also be triggered by treatment of compounds 2 with [2-(1-cycloheptenyl)ethynyl]carbene tungsten complex 1d.

Journal Article↗
PubMed2001

[Effects of different processing products of Cortex Phellodendri on scavenging oxygen free radicals and anti-lipid peroxidation].

OBJECTIVE: To investigate the effects of different processing products of Cortex Phellodendri on scavenging oxygen free radicals and anti-lipid peroxidation. METHOD: The oxygen free radicals generation system and mouse liver homogenate lipid peroxidation in vitro were used. RESULT: The aqueous and 80% alcohol extracts of raw, stir-fried, stir-fried with salt, stir-fried with yellow alcohol products of Cortex Phellodendri could scavenge superoxide radical(O2-.) generated through hypoxanthine-oxidase system and(.OH) generated through Fenton action, and inhibit lipid peroxidation induced by hydroxyl radical generation system, respectively. But the carbonized product has no effect. There are differences among these processed products. CONCLUSION: 80% alcohol extract of stir-fried with yellow alcohol products of Cortex Phellodendri was more intense.

Animals↗
PubMed2000

Polyether mimics of naturally occurring cytotoxic annonaceous acetogenins.

On the basis of the ionophore model, polyether analogues 4 and 6 were designed and synthesized to mimic the naturally occurring annonaceous acetogenins corossolin (2) and bullatin (5), which were discovered as members of a large family of novel polyketides with cytotoxicity, antitumoral, and other biological activities since 1982. The preliminary screening shows that they have compatible cytotoxicity with the corresponding natural annonaceous acetogenins. These results open a potential way to find more active antitumor agents with simplified structures based on natural annonaceous acetogenins.

Antineoplastic Agents↗
PubMed1999

Product ion studies of some novel arylamine adducts of deoxyguanosine by matrix-assisted laser desorption/ionization and post-source decay.

The product ions of the BH(2)(+) ions formed by the glycosidic cleavage of N-(deoxyguanosin-O(6)-yl)-2-methylaniline, 4-(deoxyguanosin-8-yl)-2-methylaniline, and N-(deoxyguanosin-1-yl)-2-methylaniline have been studied using matrix-assisted laser desorption/ionization (MALDI) and post-source decay (PSD) to identify fragment ions and pathways that may be used to differentiate their structures. All three isomers may be distinguished based on their PSD product ion spectra using only femtomole quantities of sample. N-(Deoxyguanosin-O(6)-yl)-2-methylaniline produces product ions at m/z 107 and 134 that are diagnostic for 2-methylaniline attachment to the O(6) position of guanine. The BH(2)(+) ion from 4-(deoxyguanosin-8-yl)-2-methylaniline yields a product ion formed by the consecutive losses of 17 and 42 u neutral fragments that may be regarded as specific for guanine-arylamine adducts that possess two primary amine groups. The BH(2)(+) ion from 4-(deoxyguanosin-8-yl)-2-methylaniline yields no product ions that correlate with specificity for guanine N1 substitution. However, the product ion abundance ratio of the protonated arylamine to that of the ammonia loss ion may be used to differentiate an adduct formed by N1 substitution from other arylamine adducts of guanine studied thus far.

Carcinogens↗
PubMed1999

Quantitative sensory testing and risk factors of diabetic sensory neuropathy.

The goal of this study was to identify risk factors for diabetic peripheral sensory neuropathy in type 2 diabetes mellitus in a Chinese population. Peripheral sensory neuropathy was detected by quantitative sensory testing (5.07/10 g monofilament, neurometer and 128-Hz Riedel Seiffert graduated tuning fork). Those who had two or more abnormal quantitative sensory testings were defined as having diabetic sensory neuropathy. Of the 558 non-insulin dependent diabetes mellitits subjects, 62 (11.1%) had peripheral neuropathy. In 59 (10.6%) detection was by monofilament testing, 45 (8.1%) by graduated tuning fork, and 189 (33.9%) by neurometer. In a multivariate logistic regression model, age and insulin therapy were significantly associated with peripheral neuropathy. Age, serum triglyceride, height, and fasting plasma glucose were independently associated with large fiber neuropathy. Our results confirm the previously identified multiple risk factors of diabetic neuropathy. Different quantitative sensory testings detect different nerve fiber defects. The weak correlation between these tests indicates the need to use more than one test in screening for diabetic neuropathy.

Aged↗
PubMed1999

Assessment of the function and effect of diabetes education programs in Taiwan.

A multi-center prospective study was conducted to assess the function and impact of diabetic education programs on diabetic control. A total of 208 subjects with type 2 diabetes were recruited. Diabetes self-care, assessed by questionnaire, was evaluated before, and 4 months after attending a diabetes education course. A total of 121 subjects who received advanced diabetes education courses were designated as the experimental group. A second group of 87 cases receiving a basic course served as controls. In addition to basic knowledge, the advanced education programs included dietary control, blood glucose monitoring, management of hypoglycemia, medication compliance, foot care and exercise. Diabetes self-care techniques were significantly improved in the experimental group. The overall score for diabetes self-care techniques improved in both groups at the 4th month over baseline values. The change was significant with the controls' (P < 0.001). Multiple regression analysis confirmed the intensity of diabetic education was the only significant variable correlated with the decrease of fasting blood glucose and systolic blood pressure. In conclusion, integrated and intensive diabetes education program in diabetes education centers provides an effective method for improving diabetes self-care techniques and metabolic outcome.

Aged↗
PubMed1999

Screening for the Gly40Ser mutation in the glucagon receptor gene among patients with type 2 diabetes or essential hypertension in Taiwan.

As a major counterregulatory hormone of insulin, glucagon plays an important role in regulating glucose homeostasis through its binding to the glucagon receptor. Recently a missense mutation in the glucagon-receptor gene (Gly40Ser) was found to be associated with type 2 diabetes in France and Sardinia, with a frequency as high as 4.6% and 8.3%, respectively. This mutation was also found to be associated with essential hypertension in the white population with a frequency of 5.4%. To investigate the role of this mutation in the pathogenesis of type 2 diabetes and essential hypertension in Taiwanese population, we screened 121 normal controls, 213 unrelated subjects with type 2 diabetes, and 107 unrelated subjects with essential hypertension by use of polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP). None of the Taiwanese subjects recruited in the study had this receptor mutation. Our results demonstrate a strong genetic heterogeneity among the ethnic group and suggest that the Gly40Ser mutation of the glucagon receptor gene plays little role, if any, in the pathogenesis of type 2 diabetes and essential hypertension in the Taiwanese population.

Amino Acid Substitution↗
PubMed1998

Analysis of the cytokine-stimulated human inducible nitric oxide synthase (iNOS) gene: characterization of differences between human and mouse iNOS promoters.

Expression of human inducible nitric oxide synthase (hiNOS) is under cytokine control and is transcriptionally regulated. The hiNOS and mouse iNOS (miNOS) genes are regulated differently by cytokines. To understand better the transcriptional regulation of the hiNOS gene, the 8.3-kb hiNOS promoter was characterized. Promoter activity was evaluated by transient transfection of hiNOS luciferase constructs in A549 human alveolar type II epithelium-like cells in the presence and absence of cytokines (IFN-gamma, IL-1 beta, and TNF-alpha). Important cytokine-responsive elements are located at -3665 to -5574 bp (containing two perfectly matched AP-1 sites which are not present in miNOS promoter) and -8093 to -8296 bp (one perfectly matched NF-kappa B site) of the hiNOS promoter region. Likely, these two AP-1 sites and the upstream NF-kappa B site are important in the transcriptional induction of hiNOS by cytokines. Our data demonstrate the molecular basis for the different cytokine-stimulated characteristics of hiNOS and miNOS genes.

Animals↗
PubMed1998

Percutaneous drainage of fluid collections in the extremities.

PURPOSE: To analyze the results of percutaneous drainage of fluid collections in the extremities. MATERIALS AND METHODS: From 1990-1997, 28 patients aged 14-90 years underwent percutaneous drainage of 33 fluid collections in the extremities; two patients underwent multiple drainages. Fluid collections were in the hip-groin area (n = 16), thighs (n = 6), buttocks (n = 6), knees (n = 3), calf (n = 1), and axilla (n = 1). Three intraarticular collections were included. The patients who had undergone prior procedures were eight who had undergone surgical drainage, 10 who had undergone needle aspiration, and one who had undergone surgical débridement. The two most common guidance methods of catheter placement were ultrasound localization and fluoroscopy. RESULTS: The average drainage duration was 18.2 days (range, 1-93 days). The estimated cavity sizes were 4-733 cm3. Purulent fluid was drained in 13 patients. Staphylococcus aureus was the most commonly identified organism (n = 9). Nine patients had postoperative lymphoceles; five of these patients underwent sclerotherapy. Two (7%) patients had two complications, one of which was major. Failure occurred in four (16%) of 25 patients; two needed repeat drainage for recurrence, and two needed subsequent surgery. Success could not be determined in three patients who were lost to follow-up. CONCLUSION: Percutaneous drainage of fluid collections in the extremities is an effective alternative to open-incision drainage in inpatients and outpatients.

Adolescent↗
PubMed1998

Role of an outpatient clinic in screening chronic complications of diabetes: a model for diabetes managed care.

The purpose of this study was to evaluate the need for an outpatient clinic for screening chronic complications of diabetes mellitus and to explore the major risk factors for such complications. A total of 558 patients (293 men and 265 women, aged 61.4 +/- 10.0 yr) with non-insulin-dependent diabetes mellitus were recruited. All examinations were performed in all patients except for those with previously known complications. A nonmydriatic fundus camera was used to detect retinopathy. Microalbuminuria was detected with a semiquantitative method. A monofilament, semiquantitative tuning fork and neurometer were used to detect peripheral neuropathy. The relationships of demographic and metabolic factors with diabetic complications were analyzed. Among the 558 patients, 443 (79.3%) were found to have at least one chronic complication. Less than half (41.5%) of patients had been identified as having a complication(s) before screening. The rates of undiagnosed complications ranged from 46.7% to 83.4% for each complication. The duration of diabetes, hemoglobin A1c (HbA1c), and systolic blood pressure (BP) were strongly associated with microvascular complications (p = 0.009, 0.018 and 0.037, respectively). The microvascular complication rates reached a plateau when HbA1c reached 8.0% at least among patients with a systolic BP of less than 130 mmHg. Our findings indicate that undiagnosed complications (average, 58.5%) can be found with routine screening, increasing the chances for prompt attention and early intervention. The duration of diabetes, HbA1c, and systolic BP were strongly associated with microvascular complications. Diabetes care can be improved by the implementation of a screening clinic in daily practice. Identification of the specific risk factors in a defined population in specific clinical settings will allow early modification of interventions for optimal diabetes care.

Adult↗
PubMed1997

Indium-111-diethylenetriaminepentaacetic acid-octreotide is delivered in vivo to pancreatic, tumor cell, renal, and hepatocyte lysosomes.

To better understand the factors that govern the target-to-background ratios of 111In-diethylenetriaminepentaacetic acid (DTPA) polypeptides, we studied 111In-DTPA-octreotide and a model nontargeted compound, 111In-DTPA-poly(D)lysine-biotin. We evaluated the fate of 111In-DTPA-octreotide after it localizes in somatostatin receptor-positive tissues and sought to determine why such a large fraction of these and other 111In-DTPA-polypeptides accumulate in the liver and kidneys. Biodistribution studies in rats with an implanted pancreatic adenocarcinoma demonstrated rapid accumulation of 111In-DTPA-octreotide in the pancreas and tumor. Indium-111 also accumulated in the liver and kidneys. Subcellular fractionation of the liver, kidneys, tumor, and pancreas showed that the majority of the radioactivity copurified with lysosomal enzymes. Even at 1 h, little radioactivity was found in the fractions containing a cell surface enzyme. This suggests that in each tissue, the 111In-DTPA-octreotide was rapidly shuttled from the cell surface to lysosomes. In the liver, hepatocyte lysosomes were separated from sinusoidal and Kupffer cell lysosomes by administering chloroquine prior to sacrifice. This density shift experiment indicated that 111In-DTPA-octreotide accumulated predominantly in hepatocyte lysosomes. A low molecular weight 111In-DTPA-poly(D)lysine-biotin compound was synthesized, and biodistribution studies showed substantial renal accumulation. The poly(D)lysine backbone conferred resistance to degradation, and this fact allowed determination of the distribution of this compound at the cellular level using an antibiotin antibody and immunohistochemical techniques. These experiments, as well as subcellular fractionation studies, demonstrated that the 111In-DTPA-poly(D)lysine-biotin compound accumulated in the lysosomes of proximal renal tubular cells. These results indicate that lysosomes play a critical role in the cellular physiology of radiolabeled polypeptides. Using these data, we propose a comprehensive model that summarizes the factors that govern the target to background ratios of radiolabeled polypeptides.

Adenocarcinoma↗
PubMed1997

Insertion/deletion polymorphism of the angiotensin I-converting enzyme gene in patients with hypertension, non-insulin-dependent diabetes mellitus, and coronary heart disease in Taiwan.

An insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme (ACE) gene has been identified that determines most of the plasma ACE activity genetically. Association of the D allele with insulin sensitivity and of the D/D genotype with coronary heart disease (CHD) has been reported in various ethnic populations. To study the role of this genetic polymorphism in patients with hypertension, non-insulin-dependent diabetes mellitus (NIDDM), and NIDDM with CHD in a Taiwanese population, we used a polymerase chain reaction (PCR)-based genotyping technique with an insertion-specific primer for confirmation of the I allele. One hundred ninety-seven unrelated normal controls, 67 subjects with hypertension, 107 subjects with NIDDM, and 70 subjects with NIDDM and CHD were recruited for this study; all were Han Chinese. Subjects without a history of diabetes were studied by a standard 75-g oral glucose tolerance test. Hypertension was diagnosed according to the Fifth Joint National Committee criteria, and CHD was confirmed by a history of acute myocardial infarction and coronary angiographic intervention. The frequency of the I allele of the ACE gene in the normal population was 64.2%, which was higher than reported in white populations. The prevalence of the I allele of the ACE gene was not significantly increased in subjects with hypertension (73.1%), NIDDM (62.1%), and NIDDM with CHD (65%) compared with healthy controls. The I allele of the ACE gene did not correlate with demographic and metabolic variables. I/D polymorphism of the ACE gene is not a marker for hypertension, NIDDM, or CHD in this Taiwanese population.

Age of Onset↗
PubMed1997

Anti-GAD65 autoantibody in Taiwanese patients with insulin-dependent diabetes mellitus: effect of HLA on anti-GAD65 positivity and clinical characteristics.

OBJECTIVE: Anti-GAD65 antibody has been studied widely in patients with insulin-dependent diabetes mellitus (IDDM) in many different populations. However, the prevalence of GAD65 autoantibody has not been assessed in Taiwanese patients with IDDM. We therefore characterized GAD65 antibody and investigated the effect of HLA-DR phenotypes on GAD65 autoimmunity and other clinical characteristics in Taiwanese subjects with IDDM. SUBJECTS AND MEASUREMENTS: Two hundred and twenty-five patients (male 102, female 123) with IDDM were recruited. The diagnostic criteria for IDDM were age of onset before 30 years, presence of diabetic ketoacidosis, and insulin-dependency within 3 years of onset. We employed a radioligand method to detect GAD65 antibody. HLA-DR typing was performed by the PCR-SSO techniques. Plasma C-peptide and anti-thyroid microsomal antibody were also measured. RESULTS: The prevalence of GAD65 antibody according to duration of disease were 50/91 (54.9%), 37/95 (38.9%), 8/24 (33%), and 3/15 (20%) among the groups of duration < or = 5, 6-10, 11-15, and > 15 years, respectively (p = 0.0011). There were no significant differences between GAD(+) and GAD(-) patients in age of onset (11.5 +/- 6.5 and 11.6 +/- 13.4 years, respectively), gender distribution (male:female 39:59 and 58:69, respectively) and percentage with residual beta cell function (38.8% and 29.1%, respectively). Multiple regression analysis revealed that duration of IDDM correlated inversely with residual beta cell function. Earlier onset of IDDM correlated with a loss of beta cell function and a HLA-DR phenotype containing DR3/4, DR3/3 or DR3/9. CONCLUSIONS: Prevalence of GAD65 autoantibody among Taiwanese subjects with IDDM was negatively correlated with duration of disease. Different determinants in the HLA-DR locus contributed to the clinical onset of IDDM but not to GAD autoimmunity.

Adolescent↗