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Biomedical subjects

J F Liu

Publications and source records attributed to J F Liu.

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↗
PubMed2005

Amorphouslike diffraction pattern in solid metallic titanium.

Amorphouslike diffraction patterns of solid elemental titanium have been detected under high pressure and high temperature using in situ energy-dispersive x-ray diffraction and a multianvil press. The onset pressure and the temperature of formation of amorphous titanium is found to be close to the alpha-beta-omega triple point in the P-T phase diagram. Amorphous Ti has been found to be thermally stable up to 1250 degrees C for at least 3 min at some pressures. By analyzing the conditions for producing amorphous elemental Zr and Ti, we observed a multi-phase-point amorphization phenomenon for preparing single-element bulk amorphous metals. The results reported may open a new way to preparing single-element bulk amorphous metals with a high thermal stability.

Journal Article↗
PubMed2004

Surgical treatment for cancer of the oesophagus and gastric cardia in Hebei, China.

BACKGROUND: Southern Hebei Province has one of the highest incidences of oesophageal cancer in the world. This study describes a single-centre experience with oesophagectomy for this condition. METHODS: The reported articles on surgical treatment for cancer of the oesophagus and gastric cardia from a single department between September 1952 and December 2000 were summarized and the results compared. RESULTS: Between September 1952 and December 2000, the resectability rate increased from 78.8 to 96.0 per cent for oesophageal cancer and from 69.6 to 94.8 per cent for cancer of the cardia. The surgical mortality rate decreased from 4.6 to 1.1 per cent. There was little change in the overall 5-year survival rate; it increased from 21.2 to 23.9 per cent for patients with oesophageal cancer and from 15.2 to 17.6 per cent for those with cancer of the cardia. CONCLUSION: The rate of postoperative complications and deaths following oesophagectomy for cancer has fallen steadily over the past five decades but long-term survival remains disappointing. Improved survival is likely to be dependent on earlier diagnosis and adjunctive therapies.

Cardia↗
PubMed2004

Evaluation of bone mineral density of the lumbar spine and proximal femur in population-based routine health examinations of healthy Asians.

PURPOSE: To understand the peak bone mineral density (BMD) and annual loss of BMD of the lumbar spine (L-BMD) and the proximal femur (F-BMD) and the prevalence of osteoporosis in both sexes in Taipei City, Taiwan. MATERIAL AND METHODS: The medical records from a recent 3-year period of annual health examinations at a single institution were reviewed. A total of 1514 men (mean age 49.08 +/- 13.62) and 1955 women (48.07 +/- 14.12), who lived in the Taipei area, had no major systemic disorders, and who had undergone both L-BMD and F-BMD examinations, were recruited. RESULTS: In women, peak L-BMD (1.078 +/- 0.133 g/cm2) occurred in the 30 to 39-year age group, whereas peak F-BMD (0.873 +/- 0.101 g/cm2) occurred in the 17 to 29-year age group. In men, peak L-BMD (1.095 +/- 0.137 g/cm2) and F-BMD (0.989 +/- 0.140 g/cm2) both occurred in the 17 to 29-year age group. The estimated annual bone loss was 0.69% of peak L-BMD in women over 50 years; in the proximal femur this was 0.688% in women and 0.332% in men. In women over 60 years, approximately half of the population had osteoporosis in the lumbar spine. CONCLUSION: We report descriptive BMD data of a Chinese population recruited from a Taipei urban area who underwent routine health examination. The values are similar to or higher than those of Japanese, Canadian and Greek populations. L-BMD was lower than that in the Lebanese, and F-BMD of both sexes was lower than that reported in the Greek study.

Adolescent↗
PubMed2002

Viral load of high-risk human papillomavirus in cervical squamous intraepithelial lesions.

OBJECTIVES: This case-control study was conducted to investigate the role of viral load of high-risk human papillomaviruses (HPVs) in the development of cervical squamous intraepithelial lesions (SILs) and invasive cancers. METHODS: A total of 30 female cases who had histological evidence of low-grade SIL (n=10) or high-grade SIL and above (n=20) were identified as the case group at the Tri-Service General Hospital, Taipei between September 1998 and March 1999. In addition, 80 female controls who had normal cervical cytology were enrolled and individually matched on age (+/-5 years) and date of recruitment to each case. Cervical swabs collected from study subjects were tested for the positivity and viral load of high-risk HPVs by Hybrid Capture II assay. Additionally, subjects completed a risk factor questionnaire. RESULTS: Among sex behavioral factors studied, younger age at first intercourse was associated with a significantly elevated risk of cervical SIL and invasive cancers. With respect to HPV infection, high-risk HPV DNA was present in 70% (21/30) of case and 21% (17/80) of control subjects, resulting in an odds ratio (OR) of 6.6 [95% confidence interval (C.I.)=2.6-17.0]. Moreover, women who had a high viral load were at significantly greater risk for cervical SIL and invasive cancers than those who were infected with a low viral load (OR=18.0, 95% C.I.=3.0-108.5). CONCLUSIONS: Among the variables tested, infection with a high viral load of high-risk HPVs is the strongest determinant for cervical SIL and cervical cancers in Taiwan.

Adult↗
PubMed2001

Effects of Sheng-Mai injection on the PRPP synthetase activity in BFU-es and CFU-es from bone marrows of mice with benzene-induced aplastic anemia.

160 Kunming mice were divided at random into 3 groups. Group 1: normal control (40 mice). Group 2: aplastic anemia (AA) control (60 mice); benzene inhalation was carried out for 2.5 months and sterilized normal saline was injected i.p. for another 6 weeks. Group 3: treated AA (60 mice); benzene was administered by inhalation in a similar manner, Sheng-Mai Injection (SMI) was administered i.p. for 6 weeks after the AA models were established. SMI is a famous Chinese traditional prescription of Panax ginseng C.A. Meyer (0.1 g/ml), Ophiopogon japonicus (Thunb.) Ker-Gawl (0.312 g/ml) and Fructus Schisandrae (0.158 g/ml). Activities of phosphoribosylpyrophosphate (PRPP) synthetase in BFU-Es and CFU-Es were estimated by ion pair reversed phase HPLC (IPrHPLC). Accompanying the sharp drop in counts of erythroid progenitor cells, the PRPP synthetase activity in CFU-Es of AA mice was reduced significantly (P<0.01), whereas there were no remarkable changes of this enzyme activity in their BFU-Es compared with the control group. Both the counts of erythroid progenitor cells and PRPP synthetase activity in CFU-Es returned nearly to normal levels following treatment with SMI of mice in Group 3 (P<0.01). Our results suggest that the attenuation of PRPP synthetase activity in peripheral erythrocytes of AA patients may originate from the weakening of activity of this enzyme in CFU-Es from their bone marrow. The impairment of PRPP formation would explain ATP depletion and disorders of energy metabolism in AA erythrocytes. SMI can distinctly increase the reduced quantity of erythroid progenitor cells and promote rapid restoration of PRPP synthetase activity in CFU-Es of AA mice.

Administration, Inhalation↗
PubMed2001

CD40 activation of carcinoma cells increases expression of adhesion and major histocompatibility molecules but fails to induce either CD80/CD86 expression or T cell alloreactivity.

A major obstacle for the development of cancer immunotherapy is the poor capacity of most tumor cells to present antigen. It has previously been shown that ligation of CD40 on the surface of malignant B cells results in the induction of efficient antigen presentation primarily because of upregulated expression of MHC, costimulatory, and adhesion molecules. Ongoing clinical trials are testing the impact of CD40 ligation as immunotherapy for B cell malignancies. Because CD40 is also widely expressed in carcinomas, we studied whether CD40 activation of these cells using soluble recombinant trimeric human CD40 ligand (srhCD40L) can also induce T cell responses. Here, we show that carcinoma cells upregulate expression of CD54 and MHC molecules following in vitro exposure to srhCD40L but do not upregulate CD80 or CD86. CD40-activated carcinoma cells failed to trigger mixed lymphocyte reactions, in sharp contrast to CD40-activated lymphoma cells for which CD40 activation, as expected, resulted in increased expression of MHC, adhesion, and costimulatory molecules, and generated brisk allogeneic lymphocyte reactions. Retroviral-mediated expression of CD80 in carcinoma cells, with or without CD40 activation, triggered mixed lymphocyte reactions, provided cells were treated with IFN-gamma. Thus, the cell surface phenotype induced on carcinoma cells following CD40 activation is not fully capable of inducing T cell proliferation; however, these results support ongoing efforts to exploit costimulation in clinical efforts aimed at increasing carcinoma immunogenicity.

Antigen Presentation↗
PubMed2001

Distribution of enantiomers of trans-tramadol and trans-O-demethyltramadol in central nervous system of rats.

AIM: To investigate the distribution of the enantiomers of trans-tramadol (trans-T) and its active metabolite, trans-O-demethyltramadol (M1), in the central nervous system (CNS). METHODS: After a single ip dose of trans-T hydrochloride or M1, the rats were killed by decapitation. A high performance capillary electrophoresis (HPCE) method was used to determine the concentrations of enantiomers of trans-T and M1 in the serum and different brain tissues, including cerebrospinal fluid (CF), cerebral cortex (CC), corpus striatum (CS), hypothalamus (HY), cerebellum (CE), and medulla oblongata (MO). RESULTS: After ip trans-T hydrochloride, the concentrations of (+)-trans-T were higher than those of (-)-trans-T in the serum and all tested brain tissues; The concentrations of (+)-M1 were lower than those of (-)-M1 in the all tested brain tissues; The concentrations of the enantiomers of trans-T and M1 were the highest in the CC, the lowest in the CF. After ip M1, the concentrations of (+)-M1 were higher than those of (-)-M1 in the serum and all tested brain tissues; The concentrations of the enantiomers of M1 were the highest in the CC, the lowest in the CF. CONCLUSION: The concentrations of the enantiomers of trans-T and M1 varied in the serum and different brain tissues. The distribution of trans-T and M1 in the CNS of rats was stereoselective. The stereoselectivity in the distribution of M1 after M1 injection was different with that after trans-T injection.

Animals↗
PubMed2001

[Synthesis, preliminary antigastrelcosis activity and the protective effect on acute liver injury of zinc chlorin E4].

AIM: To study the synthesis of zinc chlorin e4(1), its experimental antigastrelcosis activity as well as the protection against acute liver injuries. METHODS: Chlorin e6(3) was prepared through acidic and alkaline oxidative degradation using silkworm excrement crude chlorophyll extracts as starting material. Compound 1 was synthesized via Zn(OAc)2 complex action with Chlorin e4(2) which was prepared by refluxing 3 in pyridine. Gastric ulcers were induced by abdominal injection of 0.2% indomethacin at 20 mg.kg-1 in rats. The ulcer indexes and ulcer numbers in gastric mucosa were determined. Acute liver injuries were induced by abdominal injection of 0.3% thioacetamide (TAA) or 0.3% CCl4 at 20 mg.kg-1 in mice, and activities of SGPT in mice were determined. RESULTS: Compound 1 is previously unknown. Compared with control group, abdominal administration of 1 at 100 mg.kg-1 reduced significantly the gastric ulcer index (P < 0.001) and the number of ulcer (P < 0.001) induced by indomethacin in rats. Abdominal administration of 1 at 100 mg.kg-1 x 3 exhibited marked inhibitory effects on elevated activities of SGPT induced by TAA (P < 0.02) or CCl4(P < 0.01) in mice. CONCLUSION: These results show that 1 has significant protective effect against indomethacin-induced gastric lesion in rats and TAA or CCl4 induced acute liver injuries in mice. It is suggested that 1 may be a promising new drug candidate for antigastrelcosis and liver injury protection.

Animals↗
PubMed2001

[Transportation of the enantiomers of trans tramadol and O-demethyltramadol across blood-brain barrier].

AIM: To investigate the transportation of the enantiomers of trans tramadol (trans T) and its active metabolite, O-demethyltramadol (M1) across blood-brain barrier. METHODS: Rats were sacrificed by femoral artery bleeding 1 h after i.p. administration of trans T hydrochloride, 16.7 mg.kg-1 or 50.0 mg.kg-1. Blood, cerebrospinal fluid and cerebral cortex were taken out. The enantiomers of trans T and M1 were analyzed by high performance capillary electrophoresis (HPCE). RESULTS: Among the three tissues, the concentration of each enantiomer of trans T and M1 was the highest in the cerebral cortex, and the lowest in the cerebrospinal fluid. In the serum, the concentration of (+)-trans T was higher than that of (-)-trans T, and the concentrations of the enantiomers of M1 were similar. In the cerebrospinal fluid and cerebral cortex, the concentration of (+)-trans T was higher than that of (-)-trans T, and the concentrations of (+)-M1 was lower than that of (-)-M1. CONCLUSION: The transportation across blood-brain barrier of the enantiomers of trans T and M1 was stereoselective. In the brain tissues, the concentrations of (+)-trans T and (-)-M1 were higher than those of their enantiomers.

Analgesics, Opioid↗
PubMed2001

[Study on the interaction between methylene blue and bovine serum albumin by fluorescence spectroscopy].

The binding characteristics of methylene blue (MB) and bovine serum albumin (BSA) has been studied by fluorescence spectroscopy in aqueous solution. The results show that the equilibrium constant KA = 3.44 x 10(5) L.mol-1, the number of binding sites n = 1.03, and the quenching mechanism of fluorescence of BSA by MB is a static quenching procedure. The binding distance between MB and BSA and the energy transfer efficiency are obtained based on the theory of Förester spectroscopy energy transfer. The effect of MB on the conformation of BSA is further analyzed using synchronous fluorescence spectrometry.

Animals↗
PubMed2000

Risk factor analysis of post-operative mortality in oesophagectomy.

Oesophagectomy for cancer is associated with a significant incidence of post-operative complications and death, and so this study sought to determine objective criteria which could better predict operative risk. Clinical risk factors for oesophagectomy and the results of objective investigations were assessed prospectively by independent surgical and intensive care specialists and a multivariate analysis was used to develop a scoring system for predicting operative risk. From September 1994 to June 1997, 32 patients from an overall experience of 70 oesophagectomy procedures for cancer at the Royal Adelaide Hospital were entered into this study. Hypertension, a history of previous cigarette smoking and FEV1/FVC were identified as independent predictors of the post-operative outcome. Age and FEV1/FVC were also significantly associated with the occurrence of cardiovascular and pulmonary complications respectively. The average risk score was 4.8 +/- 4.5 (mean +/- SD) for patients who died, 2.9 +/- 2.9 for patients who developed post-operative complications and 2.6 +/- 2.1 for patients who had an uncomplicated recovery. The likelihood of post-operative mortality and morbidity was highest in patients with a score of 5 or more. Mortality rates of different patient groups undergoing oesophagectomy by the same surgeons during the same time period were also compared, showing greatly different mortality rates. Important risk factors can be identified preoperatively, and a scoring system can be used to provide objective criteria which can be used to identify patients at an increased risk of post-operative complications and death. A prospective study of this scoring system is now needed to determine whether it proves useful in rejecting patients for surgery who would otherwise have undergone oesophagectomy.

Adult↗
PubMed2000

Virologic factors related to interferon-alpha-induced thyroid dysfunction in patients with chronic hepatitis C.

OBJECTIVE: Hepatitis C virus (HCV), being reported to be associated with a high prevalence of serological markers of autoimmunity in HCV-infected patients, and possibly sharing partial sequences in amino acid segments with thyroid tissue antigens, may be associated with interferon-alpha (IFN-alpha)-induced thyroid dysfunction in chronic hepatitis C patients. We conducted this study to clarify the issue. DESIGN AND METHODS: One hundred and fifty chronic hepatitis C patients with normal baseline thyroid function were treated with IFN-alpha 2a, 2b and n1 (3-6 million Units three times weekly for 24 weeks). Pretreatment sera were tested for HCV genotype and HCV RNA levels. Serum thyrotropin, total thyroxine and free thyroxine index were performed every 4 weeks for 24 weeks followed by every 8 weeks for another 24 weeks. RESULTS: Twenty-one (14.0%) patients developed early thyroid dysfunction (abnormal thyroid function during the first 3 months of therapy). Female gender, lower HCV RNA levels, IFN-alpha n1 and a lower IFN-alpha dose were significantly associated with early thyroid dysfunction. On multivariate analysis, gender, IFN-alpha preparation and HCV RNA levels were the significant factors associated with early thyroid dysfunction. Seven (4.7%) patients developed thyroid dysfunction during the second 3 months of IFN-alpha therapy. Taken together, 18.7% patients developed thyroid dysfunction. Female, mixed HCV genotype infection and lower HCV RNA levels were significantly associated with thyroid dysfunction. However, only gender remained significantly associated with IFN-alpha-induced thyroid dysfunction in multivariate analysis. CONCLUSIONS: The virologic features of HCV may be associated with thyroid dysfunction in chronic hepatitis C patients treated with IFN-alpha. Nevertheless, gender still plays the most important role in IFN-alpha-induced thyroid dysfunction.

Adolescent↗
PubMed2000

Effect of oxidized frying oil and vitamin C levels on the hepatic xenobiotic-metabolizing enzyme system of guinea pigs.

The influence of oxidized frying oil (OFO) on the guinea pig hepatic microsomal xenobiotic-metabolizing enzyme system in the presence of different amounts dietary vitamin C was investigated. Weanling male guinea pigs were divided into four groups and were fed 15% oxidized frying oil diets supplemented with vitamin C at 300, 600, or 1,500 mg/kg (experimental diets) or a control diet that contained 15% fresh untreated soybean oil with 300 mg/kg of vitamin C, respectively. After 60 d, guinea pigs were euthanized and phase I and phase II xenobiotic-metabolizing enzymes in the liver were determined. Compared with the fresh oil diet fed the control group, the relative liver weight was higher in the OFO-fed groups. Hepatic microsomal protein and cytochrome P450 contents were significantly higher in OFO-fed guinea pigs than in the control group. Both values increased in response to increased intake of vitamin C. The activities of phase II relative components, including UDP-glucuronyl transferase, UDP-glucuronyl dehydrogenase and beta-glucuronidase, of guinea pigs fed the OFO diets supplemented with 300 mg vitamin C/kg were significantly higher than those of guinea pigs fed the control diet. However, the phase II relative components decreased with increasing vitamin C content in the diet. The results demonstrate that both dietary OFO and vitamin C in guinea pigs induce hepatic xenobiotic-metabolizing enzymes, but the level of induction is modulated by the dietary vitamin C level.

Animals↗
PubMed2000

Forms of cytochrome P450 in the liver microsome of oxidized frying oil-fed guinea pigs.

The aim of this study is to investigate the influence of oxidized frying oil (OFO) on the induction of individual forms of cytochrome P450 (CYP450) in guinea pigs. The OFO samples were obtained by frying potato chips in soybean oil at 200+/-5 degrees C for 24 h. Sixteen male weaning guinea pigs were fed for 12 wk on a diet which included 15% of either OFO or fresh soybean oil supplemented with 300 ppm ascorbic acid. It was demonstrated that guinea pigs fed with the OFO diet (D300) exhibited inferior growth rates and lower feed efficiency than the control group (F300). The vitamin C contents of plasma, liver, and kidney in the D300 group were lower than those in the F300 group. Further, the thiobarbituric acid-reactive substance content in D300 liver and kidney was higher than that in the F300 equivalent. The liver UDP-glucuronyl-transferase activity in the D300 group was higher than that in the F300 group, and there was no difference in comparing the glutathione-S-transferase activity levels of the two groups. Notably, the total CYP450 content and the NADPH-cytochrome c reductase activity were significantly elevated in the D300 group. The ethoxyresorufin O-deethylase activity, which mainly represents CYP1A1 activity, for the detection of CYP450 isozyme characteristics was elevated more in the D300 than in the F300 group. There was no difference in the pentoxyresorufin O-dealkylase activity, which mainly reflects the CYP2B isozyme, between the two groups. However, the quantity of CYP1A1 isoform determined in the D300 group did not differ from that in the F300 group, as revealed by SDS-PAGE and Western blot testing. Our results demonstrate that the relative enzyme activity to CYP1A1-like activity of the guinea pig hepatic xenobiotic metabolizing enzyme system may be induced by OFO feeding, but more advanced research is needed to identify the predominant form of CYP450 isozyme induced as a result of this condition.

Animals↗
PubMed2000

Clinics in diagnostic imaging (51). Multiloculated cerebral abscesses due to paradoxical cardiac emboli.

A 19-year-old woman with congenital cyanotic heart disease (Epstein anomaly and ventricular septal defect) had persistent headaches and intermittent fever for five weeks. Physical examination revealed central cyanosis, finger clubbing and fever. The leucocyte count was elevated. Cerebral MR imaging showed the characteristic features of brain abscesses in the right frontal lobe, including multiloculation with adjacent satellite lesions, ring enhancement, T1-hyperintense and T2-hypointense signal areas within the abscess rim, as well as hypointense internal concentric rings on T2-weighted images. The diagnosis of brain abscesses was confirmed by craniotomy and pus drainage. She made a good recovery with a combination of antibiotics and surgery. Follow-up CT scans showed only changes of encephalomalacia at the healed abscess site. The aetiology, clinical features, and the role of CT and MR imaging in the diagnosis and management of brain abscess are discussed.

Adult↗
PubMed2000

[Treatment of nasofacial hemangioma with interventional embolization and pingyungmycin injection].

OBJECTIVE: To investigate a new method with interventional embolization and pingyugmycin injection for treating nasofacial Hemangioma. METHOD: The fillets and coil were used for interventional embolization facial artery, internal maxillary artery, temporal superficial artery, and pingyungmycin injected for 4 patients. RESULT: The tumor and vascular beat in this series of 4 patients were disappeared by follow up of one year. There are not nasal obstruction and epistaxis. CONCLUSION: Treatment with interventional embolization and pingyungmycin injection is a safe and effective method for nasofacial hemangioma.

Adolescent↗