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Biomedical subjects

C Y Liu

Publications and source records attributed to C Y Liu.

At least 55 records · Page 3Linked to original sources
PubMed2001

Risk factors of catheter-related infections in total parenteral nutrition catheterization.

BACKGROUND: The use of central venous catheter for administration of total parenteral nutrition (TPN) is a risk factor of catheter-related infections (CRIs) that are associated with increased morbidity and mortality, prolonged hospitalization, and increased medical costs. The purpose of this study is to evaluate the risk factors of CRIs in patients with administration of TPN. METHODS: A total of 1134 patients receiving TPN between January, 1996 and December, 1998 were studied. The category of infection included definite catheter-related bloodstream infection (CR-BSI), probable CR-BSI, and insertion site infection. Statistical analysis of risk factors was performed. RESULTS: A total of 131 episodes of CRI occurred, representing an infection rate of 11.46%. Ninety-three episodes (8.1%) had probable CR-BSI, 13 episodes (1.1%) had definite CR-BSI, and 25 episodes (2.2%) had insertion site infection. Duration of TPN infusion and frequency of catheter insertion showed statistically significant difference by logistic regression multivariate analysis. The isolated organisms were in sequence of coagulase-negative Staphylococci (19.4%), Staphylococcus aureus (17.2%) and Candida albicans (14.4%). CONCLUSIONS: Risk factors influencing the occurrence of CRI in TPN administration were multifactorial; however, duration of TPN infusion and frequency of catheter insertion were the main factors in our study.

Adult↗
PubMed2001

Comparative study of ceftibuten and cefixime in the treatment of complicated urinary tract infections.

Between August 1996 and May 1998, a total of 62 patients who had complicated urinary tract infections treated at the Taipei Veterans General Hospital were enrolled into this study. This prospective, randomized, open-labeled trial aimed at comparing the efficacy and safety of ceftibuten and cefixime, prescribed each at a dose of 200 mg twice daily, in treating complicated urinary tract infection. Seventeen patients were later excluded from the analysis because of resistant pathogens (7 patients), uncomplicated urinary tract infection (6), initial culture negative for bacteria (3), and infective endocarditis (1). The remaining 45 patients were categorized into ceftibuten (n=23; mean age, 71.3 years) and cefixime (n=22; mean age, 62.8 years) treatment groups. No significant difference in demographic data and clinical characteristics was found between the 2 groups. The clinical efficacy rate (78.3% vs 77.3%, p=0.9) and bacteriological eradication rate (52.2% vs 63.6%, p=0.08) were similar between the ceftibuten and the cefixime group. Adverse effects caused by ceftibuten treatment included diarrhea and slight elevation of the serum level of liver transaminase in 2 (6.5%) patients. Those caused by cefixime treatment included slight elevation of serum level of liver transaminase in 2 (6.5%) patients and skin rash in 1 (3.2%) patient. All of these adverse effects resolved quickly after the regimen had been completed, and no patient discontinued the regimen because of the adverse effects. The results suggest that oral administration of ceftibuten 200 mg twice daily is as effective and safe as oral administration of cefixime 200 mg twice daily in the treatment of complicated urinary tract infections.

Adult↗
PubMed2001

Characteristics of patients with Burkholderia cepacia bacteremia.

Burkholderia cepacia has become an important pathogen of infections in immunocompromised and nosocomial patients. The characteristics of 42 episodes of B. cepacia bacteremia in 40 patients admitted to the Taipei Veterans General Hospital between January 1997 and December 1999 were retrospectively analyzed. Factors that adversely influenced the mortality rate included respiratory failure, an unknown infection source, a period in an intensive care unit, and shock. Most of the patients had serious underlying diseases, such as diabetes mellitus, malignancy, congestive heart failure, and chronic obstructive pulmonary disease. The mean time for a positive blood culture was 45 days after admission. The overall mortality rate was 28.6% (12/42), and 44.4% (12/27) of all deaths were directly related to B. cepacia bacteremia. Polymicrobial bacteremia was found in 5 patients. Ceftazidime was the most effective antimicrobial agent in vitro, whereas chloramphenicol, imipenem, and trimethoprim/sulfamethoxazole were less effective alternatives. Appropriate antibiotic therapy was given to 30 patients, most of whom responded to the therapy except for 5 who died despite receiving appropriate treatment. Although B. cepacia infection develops in a relatively small proportion of hospitalized individuals, it has a major impact on morbidity and mortality. In view of the fact that B. cepacia develops resistance to a wide range of antimicrobial agents, ceftazidime and/or trimethoprim/sulfamethoxazole should be the drug of choice for empiric therapy.

Adolescent↗
PubMed2001

[Clinical study on treatment of exogenous infection caused fever by infantile umbilical paste].

OBJECTIVE: To observe the effect of infantile umbilical paste (IUP) in abating infantile fever. METHODS: Two hundred and twenty cases were randomly divided into two groups, the 120 cases in Group A were treated with IUP and the 100 cases in Group B treated with compound Aspirin (APC). The effect in abating fever and side-effects were observed. RESULTS: The total effective rate of the two groups were not statistically different (P > 0.05). But a better effect in abating fever was shown in Group A 4 hrs later (P < 0.01). The effect in patients of age under 1 year was the best. CONCLUSION: IUP has good effect in abating infantile fever, and it shows no influence on white blood cells, liver and kidney functions.

Administration, Cutaneous↗
PubMed2001

[Effect of nucleus raphe obscurus on myoelectric activity of sphincter of Oddi in rabbits].

The aim of the present study was to investigate the role of nucleus raphe obscurus (NRO) in regulating the motility of sphincter of Oddi (SO). After fasting about l8~24 h, the rabbits were anesthetized with urethane (1.0 g/kg), and the myoelectric signals of SO were induced by a pair of copper electrodes inserted into the subsera. The results of microinjection of various drugs into NRO are as follows. After glutamate (340 mmol/L, 0.1 microl) was injected, activity of SO was excited. With microinjection of GABA (1 mol/L,0.1 microl), the spike burst of SO was inhibited. Following microinjection of ketamine (180 mmol/L, 0.1 microl), a kind of N-methyl-D-aspartate (NMDA) receptor antagonist, SO motility was inhibited and the effect of glutamate was abolished. Injection of 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) (2 mmol/L, 0.1 microl), a non-NMDA receptor antagonist, also excited the myoelectric activity of SO, but did not inhibit the effect of glutamate. The effect of glutamate was abolished by intravenous injection of atropine (0.2 mg/kg) or bilateral vagotomy, but not by injection of phentolamine (1.5 mg/kg) or propronalol (1.5 mg/kg), or by transection of the spinal cord. The above results indicate that NRO mediation of SO activity is due to the effect of glutamate on the NMDA receptors in the nucleus, the output of which is sent through vagal nerve and peripheral M cholinergic receptor to exert excitation of gallbladder motility.

Animals↗
PubMed2000

Analysis of the human lumican gene promoter.

The human lumican gene was shown to possess one major transcription start site, resulting in exon 1 of the gene giving rise to the first 74 base pairs (bp) of the 5'-untranslated region. About 1.6 kilobase pairs of upstream promoter sequence were sequenced and analyzed to identify elements responsible for gene expression. No typical TATAA sequence was identified in the vacinity of the transcription start site, but an atypical TATCA sequence residing 41 bp upstream was shown to be necessary for transcription, although it was incapable of supporting transcription by itself. A GC box residing 74 bp upstream of the transcription start site also was essential for the initiation of transcription. Sp3 was identified as the transcriptional activator binding to the GC box. No additional elements that significantly modulated transcription were noted in the promoter sequence analyzed, when using human adult chondrocytes as the cell source for transfection in reporter assays. In contrast, reporter assays carried out in human fetal lung fibroblasts, where lumican expression is deplete, revealed the presence of a repressor element located between 384 and 598 bp upstream of the transcription start site. A GATA-binding site located between bp -386 and -391 was identified as being necessary for repression of transcription. The mouse lumican promoter does not possess an equivalent site, and this may explain why the lumican gene is expressed in fetal murine cartilage but not in fetal human cartilage.

Animals↗
PubMed2000

Preparation and evaluation of an imidazole-coated capillary column for the electrophoretic separation of aromatic acids.

An imidazole-coated capillary column for electrophoresis has been prepared by means of organosilanization. With mesityl oxide as neutral marker, the results indicated that the electroosmotic flow of the bonded phase displays a dramatic difference in pH dependence in comparison with that of the bare fused-silica column. The presence of positive charges on the coating surface and the anionic exchange property, due to the cationic property of the imidazole group at pH values below 6, allows the separation of geometric isomers that are very similar in ionic mobility. Separation parameters including buffer composition and concentration, pH, applied voltage, and the influence of other additives were investigated. By using acetate buffer (100 mM, pH 5.2) and an applied voltage of -15 kV with UV detection at 212 nm, the separation of 11 aromatic acids including mono-, di-, tri- and tetra-carboxylic acids could be achieved in less than 14 min. The average plate number was 3 x 10(5)/m. With acetate buffer (25 mM, pH 5.5) and an applied voltage of -25 kV, the addition of silver nitrate or beta-cyclodextrin significantly improved the resolution of some more highly charged carboxylic acids.

Acids↗
PubMed2000

An analysis of the interaction between mouse apolipoprotein B100 and apolipoprotein(a).

The assembly of lipoprotein(a) (Lp(a)) involves an initial noncovalent interaction between apolipoprotein (apo) B100 and apo(a), followed by the formation of a disulfide bond between apoB100 cysteine 4326 and apo(a) cysteine 4057. The structural features of apoB100 that are required for its noncovalent interaction with apo(a) have not been fully defined. To analyze that initial interaction, we tested whether apo(a) could bind noncovalently to two apoB proteins that lack cysteine 4326: mouse apoB100 and human apoB100-C4326G. Our experiments demonstrated that both mouse apoB and the human apoB100-C4326G bind noncovalently to apo(a). We next sought to gain insights into the apoB amino acid sequences required for the interaction between apoB100 and apo(a). Previous studies of truncated human apoB proteins indicated that the carboxyl terminus of human apoB100 (amino acids 4330-4397) is important for Lp(a) assembly. To determine whether the carboxyl terminus of mouse apoB100 can interact with apo(a), transgenic mice were produced with a mutant human apoB gene construct in which human apoB100 amino acids 4279-4536 were replaced with the corresponding mouse apoB100 sequences and tyrosine 4326 was changed to a cysteine. The mutant apoB100 bound to apo(a) and formed bona fide disulfide-linked Lp(a), but Lp(a) assembly was less efficient than with wild-type human apoB100. The fact that Lp(a) assembly was less efficient with the mouse apoB sequences provides additional support for the notion that sequences in the carboxyl terminus of apoB100 are important for Lp(a) assembly.

Amino Acid Substitution↗
PubMed2000

Ligand-independent dimerization activates the stress response kinases IRE1 and PERK in the lumen of the endoplasmic reticulum.

IRE1 and PERK are type I transmembrane serine/threonine protein kinases that are activated by unfolded proteins in the endoplasmic reticulum (ER) to signal adaptive responses. IRE1 is present in all eukaryotic cells and signals the unfolded protein response through its kinase and endoribonuclease activities. PERK signals phosphorylation of a translation initiation factor to inhibit protein synthesis in higher eukaryotic cells but is absent in the Saccharomyces cerevisiae genome. The amino acid sequences of the amino-terminal ER luminal domains (NLDs) from IRE1 and PERK display limited homology and have diverged among species. In this study, we have demonstrated that the NLD of yeast Ire1p is required for signaling. However, the NLDs from human IRE1alpha and murine IRE1beta and the Caenorhabditis elegans IRE1 and PERK function as replacements for the S. cerevisiae Ire1p-NLD to signal the unfolded protein response. Replacement of the Ire1p-NLD with a functional leucine zipper dimerization motif yielded a constitutively active kinase that surprisingly was further activated by ER stress. These results demonstrate that ER stress-induced dimerization of the NLD is sufficient for IRE1 and PERK activation and is conserved through evolution. We propose that ligand-independent activation of IRE1 and PERK permits homodimerization upon accumulation of unfolded proteins in the lumen of the ER.

Amino Acid Sequence↗
PubMed2000

Perceptual alternation in obsessive compulsive disorder--implications for a role of the cortico-striatal circuitry in mediating awareness.

Mounting evidence suggests that obsessive compulsive disorder (OCD) results from functional aberrations of the fronto-striatal circuitry. However, empirical studies of the behavioral manifestations of OCD have been relatively lacking. The present study employs a behavioral task that allows a quantitative measure of how alternative percepts are formed from one moment to another, a process mimicking the brain state in which different thoughts and imageries compete for access to awareness. Eighteen patients with OCD, 12 with generalized anxiety disorder, and 18 normal subjects participated in the experiment, in which they viewed one of the three Schröder staircases and responded by pressing a key to each perceptual reversal. The results demonstrate that the patients with OCD have a higher perceptual alternation rate than the normal controls. Moreover, the frequency of perceptual alternation is significantly correlated with the Yale-Brown obsessive compulsive and the Hamilton anxiety scores. The increase in the frequency of perceptual reversals cannot easily be accounted for by learning or by different patterns of eye fixations on the task. These results provide further evidence that an impairment of the inhibitory function of the cortico-striatal circuitry might underlie the etiology of OCD. The implications of the results for a general role of the cortico-striatal circuitry in mediating awareness are discussed.

Adult↗
PubMed2000

Effects of estrogen on cognition, mood, and cerebral blood flow in AD: a controlled study.

OBJECTIVE: To examine the effects of estrogen therapy on cognition, mood, and cerebral blood flow in patients with AD. BACKGROUND: Some studies have suggested estrogen may be effective in the treatment of AD. However, most of these studies were not controlled adequately. METHODS: Fifty female AD patients were recruited in a randomized, double-blind, placebo-controlled 12-week trial. Each member of the estrogen-treated group received conjugated estrogen (Premarin) 1.25 mg/day. The primary outcome measures were the Cognitive Ability Screening Instrument (CASI), Clinical Dementia Rating (CDR), and Clinician Interview-Based Impression of Change (CIBIC-plus). The secondary outcome measures were Behavioral Pathology in Alzheimer's Disease (BEHAVE-AD), Hamilton Anxiety Rating Scale (HARS), Hamilton Depression Rating Scale (HDRS), and 99mTc hexamethylpropylene amine oxime SPECT of the brain. RESULTS: No meaningful differences were found between the outcome measures (CASI, CDR, CIBIC-plus, BEHAVE-AD, HARS, HDRS, and cerebral blood flow) taken from the estrogen-treated group and those from the control group. CONCLUSION: A 1.25-mg/day dose of Premarin administered for 12 consecutive weeks does not produce a meaningful effect on cognitive performance, dementia severity, behavior, mood, and cerebral perfusion in female AD patients. Because estrogen therapy has been suspected of yielding adverse effects, and its therapeutic effectiveness is in doubt, additional evaluation of its role in AD treatment ought to be conducted.

Affect↗
PubMed2000

A 5-year study of the seroepidemiology of Klebsiella pneumoniae: high prevalence of capsular serotype K1 in Taiwan and implication for vaccine efficacy.

Seroepidemiology of Klebsiella pneumoniae was determined for 1000 nonrepetitive K. pneumoniae isolates collected by a medical center in Taiwan during 1993-1997. Of these, 630 isolates (63%) were from community-acquired infections; the rest were from hospital-acquired infections. The isolates were serotyped according to capsular antigen by countercurrent immunoelectrophoresis. About 77% were typeable. Serotypes K1 and K2 accounted for 21.7% and 9.3% of the isolates, respectively, followed by K57 (5.1%), K54 (4.2%), K21 (3. 3%), and K16 (3%). The frequency of serotype K1 among bacteremic isolates (30.8%) far exceeded that reported by other investigators worldwide. Molecular typing of random K1 isolates by pulsed-field gel electrophoresis revealed several different pulsotypes, suggesting a nonclonal spread. This study indicates that a Klebsiella vaccine developed in Europe is not optimal for use in Taiwan because it does not contain the most predominant serotypes-K1, K54, and K57.

Antibodies, Bacterial↗
PubMed2000

Role of lumican in the corneal epithelium during wound healing.

Lumican regulates collagenous matrix assembly as a keratan sulfate proteoglycan in the cornea and is also present in the connective tissues of other organs and embryonic corneal stroma as a glycoprotein. In normal unwounded cornea, lumican is expressed by stromal keratocytes. Our data show that injured mouse corneal epithelium ectopically and transiently expresses lumican during the early phase of wound healing, suggesting a potential lumican functionality unrelated to regulation of collagen fibrillogenesis, e. g. modulation of epithelial cell adhesion or migration. An anti-lumican antibody was found to retard corneal epithelial wound healing in cultured mouse eyes. Healing of a corneal epithelial injury in Lum(-/-) mice was significantly delayed compared with Lum(+/-) mice. These observations indicate that lumican expressed in injured epithelium may modulate cell behavior such as adhesion or migration, thus contributing to corneal epithelial wound healing.

Amino Acid Sequence↗
PubMed2000

Chronic daily headache in Chinese elderly: prevalence, risk factors, and biannual follow-up.

OBJECTIVE: To investigate the prevalence, risk factors, and prognosis of chronic daily headache (CDH) in a population of elderly Chinese subjects. METHODS: A community-based survey of registered residents > or =65 years old (n = 2,003) in two townships of Kinmen Island in 1993. A neurologist used a structured questionnaire and clinical interview to make the diagnosis of headache. Subjects who had headaches > or =15 days/month for > or =6 months in the previous year were considered to have CDH. CDH was further classified into chronic tension-type headache (CTTH), CDH with migrainous features (CDH/MF), and other CDH. Person-to-person biannual follow-up of the subjects with CDH was done in June 1995 and August 1997. RESULTS: A total of 1,533 people (77%) participated in our prevalence study. Sixty subjects (3.9%) fulfilled the criteria for CDH, with a higher prevalence in women (F/M: 5.6%/1.8%, p < 0.001). Of these subjects, 42 (70%) had CTTH, 15 (25%) had CDH/MF, and 3 (5%) had other CDH. Only 23% of those with CDH had consulted physicians for their headaches in the previous year. Multivariate logistic regression revealed the significant risk factors for CDH to be analgesic overuse (OR = 79), a history of migraine (OR = 6.6), and a Geriatric Depression Scale-Short Form score of > or =8 (OR = 2.6). The follow-up results in 1995 and 1997 showed that about two-thirds of the subjects still had CDH. Analgesic overuse (relative risk = 1.6) in 1993 was a significant predictor of persistent CDH at follow-up. CONCLUSIONS: A total of 3.9% of this elderly population had CDH, with CTTH being the most common subtype. Almost two-thirds of those with CDH had persistent frequent headaches at follow-up. Analgesic overuse was a significant predictor of a poor outcome.

Aged↗
PubMed2000

Safety of MRI-guided endovascular guidewire applications.

Magnetic radiofrequency (RF) fields applied during magnetic resonance imaging (MRI) may induce heating in devices made from conductive materials. The present paper reports on theoretical and experimental studies on the RF heating resonance phenomenon of an endovascular guidewire. A nitinol-based guidewire was inserted into a vessel phantom and imaged at 1.5 and 0.2 T with continuous temperature monitoring at the guidewire tip. The heating effects due to different experimental settings were examined. A model is developed for the resonant current and the associated electric field produced by the guidewire acting as an antenna. Temperature increases of up to 17 degrees C were measured while imaging the guidewire at an off-center position in the 1.5 T MR system. Power absorption produced by the resonating wire decreased as the repetition time was increased. No temperature rise was measured at 0.2 T. Considering the potential utility of low-field, open MR systems for MRI-guided endovascular interventions, it is important to be aware of the safety of such applications.

Blood Vessels↗
PubMed2000

High prevalence of antibiotic resistance of common pathogenic bacteria in Taiwan. The Antibiotic Resistance Study Group of the Infectious Disease Society of the Republic of China.

We analyzed the antimicrobial susceptibilities of all clinical isolates of 14 common pathogenic bacteria recovered from patients in eight medical centers in Taiwan during 1995 and 1996. Susceptibility to commonly used antimicrobial agents was tested by the disk diffusion method as recommended by the National Committee for Clinical Laboratory Standards. Of the Staphylococcus aureus isolates, 59.3% and 62% were oxacillin-resistant in 1995 and 1996, respectively, whereas 63.2% of the coagulase-negative staphylococci isolates during the study period were oxacillin-resistant. The rate of penicillin-resistance among Streptococcus pneumoniae isolates was 39.7% in 1995 and 53.7% in 1996. Macrolide-resistance was found in 71.4%, 42.1%, and 46.7% of S. pneumoniae, beta-hemolytic streptococci, and viridans streptococci, respectively, in 1996. Less than 2% of the enterococcal isolates were vancomycin resistant, but 77% of them were gentamicin resistant. Resistance to gentamicin was also common in Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii. Various degrees of resistance to ampicillin, piperacillin, cephalosporins, aztreonam, and ciprofloxacin were detected in Enterobacteriaceae, P. aeruginosa, and A. baumannii. More than 55% of Haemophilus influenzae isolates were ampicillin resistant. In summary, resistance to many antimicrobial agents in various common pathogenic bacteria is very common in Taiwan. Our results implicate that antibiotic resistance in the developing countries need to be monitored closely.

Cross Infection↗
PubMed2000

Erythromycin inhibits beta2-integrins (CD11b/CD18) expression, interleukin-8 release and intracellular oxidative metabolism in neutrophils.

Macrolides have therapeutic benefits on chronic inflammatory airway diseases. Thus, macrolides are supposed to have variable biological effects apart from antimicrobial activity. Neutrophil adherence and influx with oxidants and cytokines production implicates involvement in airway inflammation. To investigate whether erythromycin (EM) affects neutrophil activity in vitro, lipopolysaccharide (LPS)-treated neutrophils were continuously incubated for 4 h in the absence or presence of increasing doses of EM from 1 microg ml(-1) to 100 microg ml(-1) in the last 2 h. Leukocyte adhesion molecules Mac-1 and intracellular H2O2(DCFH) were determined by flowcytometric assay. IL-8 and TNFalpha in supernatant was measured by ELISA method. The expression of Mac-1 and mean intracellular DCF fluorescence intensity (DCFH) of neutrophils significantly increased after stimulation with LPS. Pretreatment with EM significantly decreased LPS induced Mac-1 expression on neutrophils compared with LPS stimulation only. EM alone (100 microg ml(-1)) also decreased Mac-1 expression on neutrophils. EM significantly reduced the LPS-increased DCFH. EM alone (100 microg ml(-1)) also caused a decrease in DCFH. Increasing doses of EM also significantly decreased the IL-8 released by LPS-stimulated neutrophils. In conclusion, EM exerts a direct effect on the neutrophils by downregulating the expression of beta2-integrin on neutrophils, thus leading to a decrease in the intracellular H2O2, as well as the production of IL-8. Our conclusion provides an explanation for the clinical efficacy of erythromycin in neutrophil-mediated airway inflammation.

Anti-Bacterial Agents↗