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Biomedical subjects

C S Liu

Publications and source records attributed to C S Liu.

At least 19 recordsLinked to original sources
PubMed2007

B-group vitamins, MTHFR C677T polymorphism and carotid intima-media thickness in clinically healthy subjects.

OBJECTIVE: Plasma B-group vitamins and age may affect the carotid intima-media thickness (IMT) in subjects with different 677TT genotype of the methylenetetrahydrofolate reductase (MTHFR) gene. DESIGN: A hospital-based cross-study. SETTING: Genomic and Vascular Center, Changhua Christian Hospital, Changhua, Taiwan. SUBJECTS: Five hundred and forty-one clinically healthy subjects. INTERVENTION: Fasting plasma, homocysteine (Hcy), vitamin B(6), vitamin B(12), folate and B-mode carotid ultrasound. RESULTS: MTHFR genotype, plasma concentrations of folate, vitamin B(6) and vitamin B(12) and age were significantly correlated to the plasma Hcy concentration. MTHFR 677TT carriers had higher concentrations of Hcy than did subjects with the CC and CT genotypes. Age, sex, body mass index and plasma Hcy were independent contributors to increase carotid IMT. However, with stratification by mean value of age and B-group vitamins concentrations, we found that at advanced age, lower plasma folate and vitamin B(12) were three risk factors involved in the enhancing effect of the MTHFR 677TT genotype on the increase of plasma Hcy and carotid IMT. CONCLUSION: MTHFR 677TT-related carotid atherosclerosis was only identified in healthy elderly subjects with lower level of plasma folate and vitamin B(12). SPONSORSHIP: Changhua Christian Hospital.

Adult↗
PubMed2005

Effect of celecoxib on Ca2+ fluxes and proliferation in MDCK renal tubular cells.

The effect of celecoxib on renal tubular cells is largely unexplored. In Madin Darby canine kidney (MDCK) cells, the effect of celecoxib on intracellular CaCa2+ concentration ([Ca2+]i) and proliferation was examined by using the Ca(2 +)-sensitive fluorescent dye fura-2 and the viability detecting fluorescent dye tetrazolium, respectively. Celecoxib (> or =1 micro M) caused an increase of [CaCa2+]i in a concentration-dependent manner. Celecoxib-induced [CaCa2+]i increase was partly reduced by removal of extracellular CaCa2+. Celecoxib-induced CaCa2+ influx was independently suggested by MnCa2+ influx-induced fura-2 fluorescence quench. In Ca(2 +)-free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca(2 +)-ATPase, caused a monophasic [CaCa2+]i increase, after which celecoxib only induced a tiny [CaCa2+]i increase; conversely, pretreatment with celecoxib completely inhibited thapsigargin-induced [CaCa2+]i increases. U73122, an inhibitor of phospholipase C, abolished ATP (but not celecoxib)-induced [CaCa2+]i increases. Overnight incubation with 1 or 10 micro M celecoxib decreased cell viability by 80% and 100%, respectively. These data indicate that celecoxib evokes a [CaCa2+]i increase in renal tubular cells by stimulating both extracellular CaCa2+ influx and intracellular CaCa2+ release and is highly toxic to renal tubular cells in vitro.

Animals↗
PubMed2005

Chitosan/cellulose acetate microspheres preparation and ranitidine release in vitro.

New microspheres containing hydrophilic core and hydrophobic coating as a controlled-release system with no toxic reagents were proposed. Water in oil in water (W/O/W) emulsion and solvent evaporation methods were used to make chitosan/ cellulose acetate (CCA) microspheres sized 200 - 400 microm. Ranitidine hydrochloride, as a model drug, was investigated for its release properties in vitro. The loading efficiency and release rate of ranitidine were affected by chitosan concentration and molecular weight. Higher loadings were obtained at lower concentrations in the interval of 1% to 2%. With chitosan at a 2% concentration microspheres could be obtained with more spherical appearance, smaller size, and higher ranitidine loading efficiency microspheres than at other concentrations. Among the different molecular weight chitosan (47, 145, 308, 499, and 1130 KD) microspheres, the high molecular weight chitosan (1130 KD) microspheres had relatively high loading efficiency (10%). Molecular weight and concentration of chitosan as well as the size of microspheres affected the release of ranitidine. Microspheres smaller than 280 microm released the drug faster than did the bigger by about 10%. The optimal condition for the preparation of the microspheres was chitosan concentration 2%, molecular weight 1130 KD. The ranitidine release from the microspheres was 30% during 48 h in phosphate-buffer saline medium.

Administration, Oral↗
PubMed2005

Econazole induces increases in free intracellular Ca2+ concentrations in human osteosarcoma cells.

Econazole is an antifungal drug with different in vitro effects. However, econazole's effect on osteoblast-like cells is unknown. In human MG63 osteosarcoma cells, the effect of econazole on intracellular Ca2+ concentrations ([Ca2+]i) was explored by using fura-2. At a concentration of 0.1 microM, econazole started to cause a rise in [Ca2+]i in a concentration-dependent manner. Econazole-induced [Ca2+]i rise was reduced by 74% by removal of extracellular Ca2+. The econazole-induced Ca2+ influx was mediated via a nimodipine-sensitive pathway. In Ca2+ -free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca+ -ATPase, caused a [Ca2+]i rise, after which the increasing effect of econazole on [Ca2+]i was abolished. Pretreatment of cells with econazole to deplete Ca2+ stores totally prevented thapsigargin from releasing Ca2+. U73122, an inhibitor of phospholipase C, abolished histamine (an inositol 1,4,5-trisphosphate-dependent Ca2+ mobilizer)-induced, but not econazole-induced, [Ca2+]i rise. Econazole inhibited 76% of thapsigargin-induced store-operated Ca2+ entry. These findings suggest that in MG63 osteosarcoma cells, econazole increases [Ca2+]i by stimulating Ca2+ influx and Ca2+ release from the endoplasmic reticulum via a phospholipase C-independent manner. In contrast, econazole acts as a potent blocker of store-operated Ca2+ entry.

Antifungal Agents↗
PubMed2004

Calculations of cellular microdosimetry parameters for alpha particles and electrons.

The cellular microdosimetry parameters including the cellular S-value and the single-event specific energy distribution for alpha particles and electrons are important in radiation dosimetry and biology. These parameters may be used to determine the relative biological effectiveness of radiations in the boron neutron capture therapy. In the present work, such parameters were calculated for different source to target region combinations, i.e. cell surface, cytoplasm, nucleus and cell. Calculations were made using a semi-analytical model that simulated the emission of alpha particles or electrons by the Monte Carlo method and calculated the energy imparted to the target volume by the analytical method. Delta particle equilibrium and partial delta particle equilibrium were applied to alpha particles and electrons, respectively. Range-energy relations were employed to determine the incident and emerging energies of the primary particles. For electrons, the fraction in the energy loss resulting from the generation of bremsstrahlung and high-energy secondary electrons was estimated. The energy loss straggling of electrons entering and leaving a target volume was also estimated. Calculated cellular S-values were compared to corresponding data of the MIRD Committee. Calculated single-event specific energy distributions were also compared to results calculated using the Penelope code.

Alpha Particles↗
PubMed2003

Electron- or hole-assisted reactions of H defects in hydrogen-bonded KDP.

We present an ab initio study of the stability and defect reactions of neutral and charged H interstitial (H(i)) and H vacancy (H(v)) in KH2PO4 (KDP). We find that while there is no interaction between the neutral H(i) and the host, the addition of an electron leads to the ejection of a H host atom and the subsequent formation of an interstitial H2 molecule and a H(v). In sharp contrast, the addition of a hole results in the formation of a hydroxyl bond. Thus, H(i) in both charged states severs the H-bonded network. For the H(v), the addition of a hole leads to the formation of a peroxyl bridge. The neutral H(i) and the positively charged H(v) induce states in the gap. The results elucidate the underlying atomic mechanism for the defect reactions suggested by experiment.

Journal Article↗
PubMed2001

Effect of genotoxic exposure to chromium among electroplating workers in Taiwan.

The objective of this study was to investigate the association between chromium (Cr) concentrations and sister chromatid exchanges (SCE) formation in Cr workers and to assess the effects of susceptible genes (glutathione S-transferase M1 and T1) on the frequency of deletion and SCE/cell. Urinary Cr concentration was significantly elevated in Cr workers (3.67 +/- 3.89 microg/g creatinine) compared to control group (1.21 +/- 1.16 microg/g creatinine, P < 0.01). There was also a significant difference of superoxide dismutase (SOD) levels between Cr workers (6.86 +/- 0.80 U/mg Hb) and controls (7.16 +/- 0.53 U/mg Hb, P < 0.01). The frequencies of SCE and high frequency cells (HFC) were significantly correlated with smoking habits and with duration of exposure to Cr. A significantly higher percentage (50%) of Cr workers had both the null GSTM1 and GSTT1 genotype as compared to 10% of the controls (P < 0.01). However, the chromosomal DNA damage effect of GSTM1 and GSTT1 genotypes, individually or in combination, was not revealed in Cr exposed workers.

Adolescent↗
PubMed2001

Structure formation and tearing of an MeV cylindrical electron beam in a laser-produced plasma.

The stability of a cylindrical, solid hot electron beam propagating in a high density plasma has been studied using a two-dimensional, hybrid Darwin code. The initially solid beam evolves into a hollow, annular beam due to the Weibel instability and generates strong magnetic fields on both sides of the annular ring. The annular structure subsequently breaks up into several beamlets via a mechanism similar to a tearing instability. It is found that the magnetic fields parallel to the direction of beam propagation also grow due to the tearing process.

Journal Article↗
PubMed2001

Comparison of MALT and non-MALT primary large cell lymphoma of the stomach: does histologic evidence of MALT affect chemotherapy response?

BACKGROUND: Although the clinicopathologic features of low grade gastric MALToma (lymphoma of mucosa-associated lymphoid tissue) recently have been well delineated, the significance of identifying histologic evidence of MALT origin in a primary high grade gastric lymphoma is less clear. The authors sought to address this issue and, in particular, to clarify if MALT and non-MALT primary large cell gastric lymphoma might have a different response to systemic chemotherapy. METHODS: The authors reviewed the pathologic specimens of all patients who had a diagnosis of primary large cell lymphoma of the stomach and who had been treated primarily by systemic chemotherapy in our institutions January 1, 1988-December 31, 1998. The patients were divided into two groups by experienced hematopathologists, based on the presence or absence of histologic features suggestive of MALToma, including typical lymphoepithelial lesions and infiltration of characteristic centrocyte-like cells. Disease staging was done according to the AJCC/UICC system with Musshoff modification. The median number of gastric biopsies for each patient was 7 (range, 1-21). RESULTS: Seventeen patients with and 26 patients without histologic evidence of MALToma were identified. Clinical features were similar between the two groups except that a greater proportion of patients without evidence of MALToma had elevated levels of serum lactate dehydrogenase (50% vs. 12%, P = 0.01). The median duration of follow-up for the 43 patients was 46.5 months (range, 17-124 mos). All patients received standard systemic chemotherapy including anthracyclines or anthracenedione. The response rate was 88.2% for patients with evidence of MALToma and 57.7% for those without (P = 0.03). The 5-year overall survival rate was 80.5% for patients with evidence of MALToma and 48.9% for those without (P = 0.02). Multivariate analysis indicated that response to chemotherapy, disease stage (Stage I and II-1 vs. Stage II-2, III, and IV), and the presence of MALToma features were independent prognostic factors for overall survival. CONCLUSION: The results of this relatively small study series suggested that the presence of histologic features of MALToma in patients with primary large cell gastric lymphoma might have been associated with a better response to systemic chemotherapy and a better prognosis. Further studies to consolidate this conclusion are necessary.

Adult↗
PubMed2001

Multidimensional high performance liquid chromatography--capillary electrophoresis separation of a protein digest: an update.

The trypsin digest of a mixture of two proteins, namely cytochrome c and myoglobin, was first separated in the first dimension by high-performance liquid chromatography (HPLC). Fractions from the HPLC were collected every 30s with the aid of a fraction collector into a 96-well microtiter plate. After concentration, all the collected fractions were analyzed simultaneaosly in the second dimension by a 96-array capillary electrophoresis system. The labeled peptides were detected by laser-induced fluorescence. An internal standard, allura red, was added to all the fractions, prior to capillary electrophoretic analysis. The internal standard serves two functions, migration time correction and signal intensity correction. The data are presented in two different formats, as an electropherogram of all the fractions and in a two-dimensional (2-D) format. The 2-D plot of the data shows the density of each spot, which corresponds to the concentration of the migrating peptides. The total experimental time for the HPLC and capillary electrophoretic analyses ist less than 1 h, which ist much faster than using 2-D slab-gel electrophoresis or single-capillary capillary electrophoresis.

Chromatography, High Pressure Liquid↗
PubMed2001

Cecal perforation presenting as abdominal-wall necrotizing fasciitis.

The preoperative diagnosis of a cecal perforation associated with Salmonella infection as a cause of abdominal-wall necrotizing fasciitis (AWNF) is clinically difficult. Computed tomography of the abdomen is helpful, and can detect the combined presence of a pneumoscrotum and pneumoperitoneum. Its presence indicates a patent processus vaginalis, which acts as the primary route for the spread of the intra-abdominal infectious process into the abdominal wall. An exploratory laparotomy should be done to confirm the presence of intra-abdominal pathology in order to avoid delayed treatment.

Abdominal Muscles↗
PubMed2001

Hypospadias repair using a double onlay preputial flap.

From an anatomical view, a more reasonable blood supply can be achieved in hypospadias repair using a double-faced onlay flap. A urethroplasty was performed in 15 patients with middle or posterior hypospadias using a double-faced onlay preputial flap (DOPF). In this method, the urethral plate is preserved and a double-faced preputial flap is developed. The inner face of the flap is sutured to the urethral plate to create the neourethra and the outer face together with the rest of the dorsal prepuce is used for ventral skin coverage. Postoperative complications occurred in 2 patients: 1 developed a fistula in the subcoronal region and 1 had dorsal skin necrosis and suture disruption of the glanular wings. The overall complication rate was 13%. The DOPF provides a well-vascularized ventral skin cover and reduces the area of avascular dorsal skin. The viability of the neourethra can be evaluated by simply looking at the outer face of the flap. However, the complication rate is similar to that of other techniques.

Child, Preschool↗
PubMed2001

Corneal decompensation and graft failure secondary to a broken posterior chamber poly(methyl methacrylate) intraocular lens haptic.

A 66-year-old man developed an unexplained corneal decompensation 7 years after extracapsular cataract extraction and implantation of a single-piece poly(methyl methacrylate) (PMMA) posterior chamber intraocular lens (IOL). He had penetrating keratoplasty (PKP). Two years later, he developed corneal graft failure secondary to an IOL haptic fragment in the anterior chamber angle. The patient had a repeat corneal graft and IOL exchange. The broken haptic was examined with scanning electron microscopy. The findings were consistent with late fracture of the haptic within the capsular bag, which was presumably weakened by an improper implantation technique. Fracture of a PMMA haptic should be suspected as a cause of corneal decompensation and corneal graft failure after cataract surgery. This case emphasizes the importance of safe implantation techniques.

Aged↗
PubMed2001

Biomarkers of DNA damage in patients with end-stage renal disease: mitochondrial DNA mutation in hair follicles.

BACKGROUND: DNA damage was noted in patients with end-stage renal disease (ESRD). Mitochondrial DNA (mtDNA) mutations have been proposed as a genomic biomarker in the process of human ageing, degenerative diseases and carcinogenesis. METHODS: Polymerase chain reaction (PCR) techniques were applied to detect mtDNA deletions in hair follicles, an appendage of skin, from 162 patients with ESRD. RESULTS: The incidences of the 4977 bp deletion of mtDNA in hair follicles were found to increase with age in normal control and ESRD patients. As compared with normal subjects, ESRD patients had 3.5, 2.3, 2.7, 2.3 and 1.4 times higher incidences of the 4977 bp deletion of mtDNA in the age groups of 20-30, 31-40, 41-50, 51-60 and 61-70 years, respectively. Moreover, the difference in the proportion of mtDNA with the 4977 bp deletion was statistically significant between ESRD patients and normal subjects >50 years of age. CONCLUSION: We suggest that the 4977 bp deletion of mtDNA in hair follicles may serve as one of the tissue biomarkers of genetic instability of the mitochondrial genome in ESRD patients.

Adult↗
PubMed2001

Visual activation in functional magnetic resonance imaging at very high field (4 Tesla).

OBJECTIVES: Functional magnetic resonance imaging (fMRI) at very high field strengths provides functional brain mapping with the enhanced signal to noise ratio and the larger blood oxygenation level-dependent (BOLD) effect. We report activated areas in the standard space detected by fMRI at 4 Tesla (T) during simple visual stimulation. MATERIALS AND METHODS: Twelve healthy young subjects were scanned using a 4 T scanner during binocular flashing visual stimulation. Functional images were realigned to the first scan and then spatially normalized. Individual and group data analyses were performed to identify areas of visual activation. RESULTS: Activation of the bilateral primary visual cortex (V1/V2) was observed along the entire calcarine fissure in all subjects. The activated area extended to the extrastriate cortex in all subjects. Activation of the bilateral lateral geniculate nucleus (LGN) was detected in all subjects. The group data showed activation of the bilateral primary visual cortex and the bilateral lateral geniculate nucleus. CONCLUSIONS: Robust activation of the vision-related areas was successfully obtained in all subjects using a 4 T magnetic resonance scanner. These results suggest that fMRI at very high field strengths may be effective in showing visual system physiology, and that it can be a promising method to assess visual function of human subjects.

Adult↗
PubMed2001

Functional magnetic resonance imaging of the visual system.

Functional magnetic resonance imaging (fMRI), which is a technique useful for non-invasive mapping of brain function, is well suited for studying the visual system. This review highlights current clinical applications and research studies involving patients with visual deficits. Relevant reports regarding the investigation of the brain's role in visual processing and some newer fMRI techniques are also reviewed. Functional magnetic resonance imaging has been used for presurgical mapping of visual cortex in patients with brain lesions and for studying patients with amblyopia, optic neuritis, and residual vision in homonymous hemianopia. Retinotopic borders, motion processing, and visual attention have been the topics of several fMRI studies. These reports suggest that fMRI can be useful in clinical and research studies in patients with visual deficits.

Amblyopia↗