Biomedical subjects

C F Liu

Publications and source records attributed to C F Liu.

At least 19 recordsLinked to original sources

PubMed2006

Genetic engineering of Periplaneta fuliginosa densovirus as an improved biopesticide.

The smoky-brown cockroach (Periplaneta fuliginosa) densovirus (PfDNV) has previously shown potential in urban pest control. To improve its efficacy as a biopesticide, the genome of PfDNV was engineered by inserting the insect-specific toxin gene BmKIT1 in the open reading frame encoding the major structural proteins. A green fluorescent protein (GFP) marker was tagged to the BmKIT1 at its C-terminus for in vivo imaging using Confocal laser scanning microscopy (CFSM). Using a virion rescue strategy, the genomes of recombinant and wild-type (wt) PfDNV were then cotransfected in P. fuliginosa nymphs. Reverse transcription PCR (RT-PCR) showed that the inserted BmkIT1 genes were expressed in the P. fuliginosa nymphs 48 h after cotransfection. CFSM and transmission electron microscopy also confirmed the generation of virus particles and expression of BmKIT1-GFP fusion protein in the cotransfected nymphs. The recombinant viruses remained infective to P. fuliginosa nymphs in feeding tests. Using the LT(50) bioassay method, the coninfection of the recombinant and wt PfDNV killed the P. fuliginosa nymphs approximate 32% faster than wt PfDNV only. This is the first report showing the improvement of engineered densovirus for the potential application of biopesticide.

Animals↗

PubMed2006

Physicochemical characterization of cellulose from perennial ryegrass leaves (Lolium perenne).

In this study, we investigated the physicochemical properties of the cellulosic preparations obtained from both untreated perennial ryegrass leaves and de-juiced leaves. It was found that treatment at 22 degrees C with 18% NaOH and 18% KOH for 2h, and 10% NaOH and 10% KOH for 16 h yielded 28.2%, 28.8%, 22.7%, 23.4%, respectively, of 'cellulose' residue from untreated ryegrass leaves and 35.7%, 36.8%, 32.8% and 34.6%, respectively, from the de-juiced leaves. For each cellulosic fraction, the glucose content was 71.6%, 69.6%, 67.8%, 66.7%, 69.7%, 68.6%, 63.9% and 61.7%, respectively. The structure of the cellulose samples was examined using FTIR and CP/MAS (13)C NMR spectroscopy and X-ray diffraction. The cellulosic preparations were free of bound lignin except for noticeable amounts of residual hemicelluloses (28.4-38.3%), and had intrinsic viscosities between 275.1 and 361.0 mL/g, along with molecular weights from 144,130 to 194,930 g/mol. This study found that the cellulose samples isolated from both de-juiced ryegrass leaves and the untreated leaves had a much lower percent crystallinity (33.0-38.6%) than that from wood-based fibres (60-70%) and had much shorter fibres (0.35-0.49 mm) than those of either cereal straws, bagasse or wood. In addition, a partial disruption of the hydrogen bonds and microfibrils may occur during the de-juicing process by mechanical activity, which results in a decreased cellulose crystallinity and fibre length. These findings are significant in relation to hydrolysing ryegrass cellulose for bio-ethanol production.

Carbon Isotopes↗

PubMed2006

Fractional and structural characterization of hemicelluloses from perennial ryegrass (Lolium perenne) and cocksfoot grass (Dactylis glomerata).

Sequential three-stage treatments with 80% EtOH containing 0.2% NaOH, 2.5% H2O2-0.2% EDTA containing 1.5% NaOH and 2.5% H2O2-0.2% TAED containing 1.0% NaOH at 75 degrees C for 3h released 8.0% and 10.4%, 79.1% and 77.0% and 12.9% and 12.5% of the original hemicelluloses from perennial grass and cocksfoot grass, respectively. It was found that the four alkaline peroxide-soluble hemicellulosic fractions contained higher amounts of xylose (33.4-38.2%), uronic acids (9.3-15.3%) and rhamnose (3.0-3.9%), but were lower in glucose (25.1-28.3%), galactose (13.3-15.3%) and mannose (0.4-1.5%) than those of the two alkaline EtOH-soluble hemicellulosic fractions in which glucose (32.9-36.0%), xylose (20.1-22.6%), arabinose (14.1-21.4%), galactose (16.6-19.9%), mannose (4.1-9.9%) and uronic acids (3.4-7.4%) were the major sugar components. 13C NMR spectroscopy confirmed that all the six hemicellulosic fractions were composed of galactoarabinoxylans, 4-O-methylglucuronoarabinoxylans and beta-glucan. In addition, the studies showed that the four alkaline peroxide-soluble hemicellulosic fractions were more linear and acidic and had larger molecular weights (Mw, 28,400-38,650 g mol(-1)) than those of the two alkaline EtOH-soluble hemicellulosic fractions (Mw, 16,460-17,420 g mol(-1)).

Chemical Fractionation↗

PubMed2005

Comparative study of alkali- and acidic organic solvent-soluble hemicellulosic polysaccharides from sugarcane bagasse.

Two-stage treatments of sugarcane bagasse with mild alkali and acidic 1,4-dioxane were performed. Pretreatment with 1M NaOH aqueous solution at 20, 25, 30, 35, and 40 degrees C for 18 h released 55.5%, 57.3%, 59.1%, 60.9%, and 62.1% of the original hemicelluloses, respectively. Post-treatment of the corresponding alkali-treated residue with 1,4-dioxane-2M HCl (9:1, v/v) at 87 degrees C for 2h, respectively, degraded 11.6%, 11.9%, 11.4%, 10.9%, and 10.6% of hemicelluloses (% dry starting material). It was found that the five alkali-soluble hemicellulosic preparations contained a much higher amounts of xylose (78.0-82.2%) and slightly higher uronic acids (4.8-5.8%), mainly 4-O-methyl-alpha-d-glucopyranosyluronic acid, but were lower in arabinose (9.3-11.7%) and glucose (2.2-4.1%) than those of the corresponding five acidic dioxane-degraded hemicellulosic fractions in which xylose (44.9-46.8%), arabinose (35.9-38.1%), and glucose (13.0-13.7%) were the major sugar constituents. The studies revealed that the five alkali-soluble hemicellulosic preparations were more linear and acidic, and had a large molecular weight (35,200-37,430 g mol(-1)) than those of the hemicellulosic fractions (12,080-13,320 g mol(-1)) degraded during the acidic dioxane post-treatment. This demonstrated that the post-treatment with acidic dioxane under the condition used resulted in substantial degradation of the hemicellulosic polymers. The 10 hemicellulosic samples were further characterized by FT-IR and 1H and 13C NMR spectroscopy, GPC and thermal analysis, and the results are reported.

Cellulose↗

PubMed2004

Comparision of interleukin-6 and malondialdehyde levels in diabetic patients in Taiwan.

The purpose of this study was to compare the levels of interleukin-6 (IL-6) and malondialdehyde (MDA) in healthy controls and diabetic patients without coronary heart disease (CHD). Fasting serum IL-6 and MDA were determined in 30 healthy controls and 52 (20 Type 1 and 32 Type 2) diabetic patients without clinical evidence of CHD. MDA was calculated as oxidative stress. The IL-6 concentration was used to evaluate the cytokine function. Results showed that the serum IL-6 and MDA concentrations are significantly higher in Type 2 diabetic patients (p<0.05). In conclusion, we demonstrated that Type 2 diabetic patients are more influenced by oxidative stress than Type 1 diabetic patients and healthy controls, because of the action of cytokine.

Adult↗

PubMed2003

Observation of a near-threshold enhancement in the pp mass spectrum from radiative J/psi-->gammapp decays.

We observe a narrow enhancement near 2m(p) in the invariant mass spectrum of pp pairs from radiative J/psi-->gammapp decays. No similar structure is seen in J/psi-->pi(0)pp decays. The results are based on an analysis of a 58 x 10(6) event sample of J/psi decays accumulated with the BESII detector at the Beijing electron-positron collider. The enhancement can be fit with either an S- or P-wave Breit-Wigner resonance function. In the case of the S-wave fit, the peak mass is below 2m(p) at M=1859(+3)(-10) (stat)+5-25(syst) MeV/c(2) and the total width is Gamma<30 MeV/c(2) at the 90% confidence level. These mass and width values are not consistent with the properties of any known particle.

Journal Article↗

PubMed2002

Nosocomial blood-stream infection in patients with end-stage renal disease: excess length of hospital stay, extra cost and attributable mortality.

Patients with end-stage renal disease undergoing haemodialysis are at high risk of nosocomial blood-stream infection (BSI), but data on the associated costs in this patient population are not available. Therefore, we conducted a retrospective matched (1:2) case-control study of such patients undergoing haemodialysis from January 1998 to December 1998 in a medical centre in southern Taiwan to determine the excess length of hospital stay, attributable mortality, and the extra cost caused by nosocomial BSI. The excess length of hospital stay was 30 days for cases vs. 16 days for controls (P<0.001), the mortality rate was 26.3% for cases vs. 0 for controls (P=0.003) (attributable mortality being 26.3%), and the median of overall costs was 131,584 dollars NT for cases vs. 65,282 dollars NT for controls (P<0.001). Based on these findings, we believe that an effective programme to minimize nosocomial BSI in this patient population would greatly reduce their medical and economic burdens.

Case-Control Studies↗

PubMed2001

Subtilisin-catalyzed synthesis of amino acid and peptide esters. Application in a two-step enzymatic ligation strategy.

We describe an efficient enzymatic approach to the synthesis of amino acid and peptide esters. The serine protease subtilisin Carlsberg (EC 3.4.21.62) was found to efficiently catalyze the specific formation of C(alpha)-carboxyl 3-hydroxypropyl or 4-hydroxybutyl esters of certain Boc-amino acids and peptides in high-content 1,3-propanediol or 1,4-butanediol solution, with substrate specificity parallel to that of the normal hydrolytic reaction. This approach can be coupled with kinetic-control reverse proteolysis in a two-step enzymatic peptide ligation scheme. [reaction: see text]

Amino Acids↗

PubMed2001

Molecular structure, dynamic expression, and promoter analysis of zebrafish (Danio rerio) myf-5 gene.

We isolated a 1,438 bp cDNA fragment that encoded Myf-5 myogenic factor of zebrafish. The deduced amino acid contained 237 residues, including the basic helix-loop-helix domain that is conserved in all known Myf-5. The zebrafish myf-5 transcripts were first detectable at 7.5 hpf, increased substantially until 16 hpf, and then declined gradually to an undetectable level by 26 hpf. During somitogenesis, zebrafish myf-5 transcripts were distributed mainly in the somites and segmental plates. Prominent signals occurred transiently in adaxial cells in two parallel rows but did not extend beyond the positive-signal somites. Various lengths of upstream region of zebrafish myf-5 fused with EGFP gene were used to carry out transgenic analysis. Results showed that a small, 82 bp (nucleotide positions from -82 to -1), regulatory cassette is sufficient to control the somite- and stage-specific expression of zebrafish myf-5 during early development.

Amino Acid Sequence↗

PubMed2001

Interpreting results in mental health research.

It is often difficult to interpret the clinical or policy significance of findings from mental health research when results are presented only in terms of statistical significance. Results expressed in terms of p values or as a metric corresponding to a mental health status scale are seldom intuitively meaningful. To help interpret the significance of research results, we demonstrate a social validity approach that relates scores on mental health status scales to four subsequent major life events. A logistic regression model is used to estimate the relation between mental health status scores and the probability of subsequent major life events, using data obtained on Medicaid beneficiaries with schizophrenia from an evaluation of the Utah Prepaid Mental Health Plan. Using this relatively simple approach will demonstrate to policy makers, clinicians, and researchers the social impact of an outcome, thereby aiding in the interpretation of the significance of results.

Adult↗

PubMed2001

Evaluation of the hepatic and renal-protective effects of Ganoderma lucidum in mice.

The antioxidative effect of hot water extract of the mushroom Ganoderma lucidum on ethanol-induced free radical generation had been studied. In order to further investigate the hepatic and renal protective mechanism of Ganoderma lucidum, rates of lipid peroxidation were determined. The hot water extract of Ganoderma lucidum dose-dependently exhibited antioxidative effect on mouse liver and kidney lipid peroxidation; our results indicated that hepatic and renal homogenates have a higher malonic dialdehyde level in an ethanol administered group than in the Ganoderma lucidum treated group. It was concluded that the hepatic and renal protective mechanism of Ganoderma lucidum, might be due at least in part to its prominent superoxide scavenging effect. Ganoderma extract could protect the liver and kidney from superoxide induced hepatic and renal damages.

Animals↗

PubMed2001

Impact of global bundled payments on hospital costs of coronary artery bypass grafting.

The Health Care Financing Administration began the Medicare Participating Heart Bypass Center Demonstration in 1991, in which hospitals and physicians are paid a single negotiated global price for all inpatient care for heart bypass patients. This article analyzed the changes in total and departmental direct variable costs during the 1991-1993 period using micro-cost data. The results indicate that all participating hospitals had significant reductions in total direct variable costs, after controlling for preoperative risk factors and postoperative outcomes. However, the patterns in cost reductions across major departments were different across hospitals. The cost reductions primarily came from nursing intensive care unit, routine nursing, pharmacy, and catheter lab.

Boston↗

PubMed2000

A comparison of folding techniques in the chemical synthesis of the epidermal growth factor-like domain in neu differentiation factor alpha/beta.

The 52-residue alpha/beta chimera of the epidermal growth factor-like domain in neu differentiation factor (NDFealpha/beta) has been synthesized and folded to form a three disulfide bridge (Cys182-Cys196, Cys190-Cys210, Cys212-Cys221) containing peptide. We investigated two general strategies for the formation of the intramolecular disulfide bridges including, the single-step approach, which used fully deprotected and reduced peptide, and a sequential approach that relied on orthogonal cysteine protection in which specific pairs are excluded from the first oxidation step. Because there are 15 possible disulfide bridge arrangements in a peptide with six cysteines, the one-step approach may not always provide the desired disulfide pairing. Here, we compare the single-step approach with a systematic evaluation of the sequential approach. We employed the acetamidomethyl group to protect each pair of cysteines involved in disulfide bridges, i.e. Cys182 to Cys196, Cys190 to Cys210 and Cys212 to Cys221. This reduced the number of possible disulfide patterns from 15 to three in the first folding step. We compared the efficiencies of folding for each protected pair using RP-HPLC, mapped the disulfide connectivity of the predominant product and then formed the final disulfide from the partially folded intermediate via 12 oxidation. Only the peptide having the Cys182-Cys196 pair blocked with acetamidomethyl forms the desired disulfide isomer (Cys190-Cys210/Cys212-Cys221) as a single homogeneous product. By optimizing both approaches, as well as other steps in the synthesis, we can now rapidly provide large-scale syntheses of NDFealpha/beta and other novel EGF-like peptides.

Amino Acid Sequence↗

PubMed2000

Cardiovascular manifestations of pheochromocytoma.

Pheochromocytomas are rare tumors that originate in chromaffin tissue and produce their distant variant effects by secretion of catecholamines, tending to mislead the emergency physicians to a wrong diagnosis. Therefore, we analyze the clinical cardiovascular manifestations in patients with pheochromocytoma to improve the diagnostic ability of the emergency physicians. All patients presenting to the Chang Gung Memorial Hospital between January 1993 and December 1997 with a final diagnosis of pheochromocytoma had their charts reviewed. The data of 25 patients including age, sex, adrenergic stimulation presentations, electrocardiographic changes, location of the tumor, and complications were analyzed. Hypertension was the most important major manifestation and fluctuation of blood pressure drew our attention to the possibility of pheochromocytoma. Six patients had abnormal electrocardiographic ST-T segment changes. Five of them had chest pain which prompted them to undergo coronary angiography before surgery, because acute coronary syndrome (unstable angina and acute myocardial infarction) was suspected initially. However, all of them turned out to have normal coronary arteries. Right-sided pheochromocytoma was found in three of these five patients. We should maintain high index of suspicion for pheochromocytoma in patients presenting with chest pain, fluctuating blood pressure, and ischemic electrocardiogram (ECG) changes despite any typical isoenzyme changes. Pheochromocytoma should also be included in the differential diagnosis of acute coronary syndrome because acute catecholamine secretion may induce chest pain and abnormal ECG changes mimicking an ischemic episode. The right-sided pheochromocytoma may present more striking electrocardiographic abnormalities and clinical manifestations.

Adolescent↗

PubMed2000

Principal inpatient diagnostic cost group model for Medicare risk adjustment.

The Balanced Budget Act (BBA) of 1997 required HCFA to implement health-status-based risk adjustment for Medicare capitation payments for managed care plans by January 1, 2000. In support of this mandate, HCFA has been collecting inpatient encounter data from health plans since 1997. These data include diagnoses and other information that can be used to identify chronic medical problems that contribute to higher costs, so that health plans can be paid more when they care for sicker patients. In this article, the authors describe the risk-adjustment model HCFA is implementing in the year 2000, known as the Principal Inpatient Diagnostic Cost Group (PIPDCG) model.

Adolescent↗

PubMed2000

[Hairy root induction and in vitro cultivation of Pueraria lobata willa. ohwi].

OBJECTIVE: To study the hairy root induction and hormone-free in vitro liquid cultivation of Pueraria lobata (Willd) Ohwi. METHOD: Co-cultivation of super-virulent Agrobacterium rhizogenes R1601 with P. lobata leaves in vitro. RESULTS: Hairy roots of rapid growth, high branches and plagiotropism developed vigorously on the surface of leaves, exhibiting rapid growth and resistance to kanamycin in hormone-free medium in vitro. CONCLUSION: A method of hairy root induction with A. rhizogenes as well as a system hairy root liquid cultivation in vitro for P. lobata have been established.

Coculture Techniques↗

PubMed1999

Outcomes for Medicaid beneficiaries with schizophrenia under a prepaid mental health carve-out.

This study examines the impact of a mental health carve-out program in Utah on mental health status of Medicaid beneficiaries with schizophrenia. Three community mental health centers contracted to provide mental health care for all Medicaid beneficiaries in their service areas under managed care arrangements, while beneficiaries in the remainder of the state remained under traditional Medicaid. A pre-post evaluation was utilized, with a contemporaneous control group of Utah Medicaid beneficiaries with schizophrenia under traditional Medicaid. From 1991 to 1994, the average beneficiary's mental health status improved, but the improvement was less under the carve-out program than under traditional fee-for-service Medicaid. The difference was the greatest for beneficiaries with the worst mental health status at baseline, with effects growing over time. Medicaid beneficiaries with schizophrenia experienced less improvement in mental health status under a carve-out arrangement for mental health care compared to what would have happened under traditional Medicaid.

Adult↗

PubMed1999

Patterns of outpatient use of mental health services for Medicaid beneficiaries under a prepaid mental health carve-out.

This study examines the impact of a mental health carve-out, the Utah Prepaid Mental Health Plan (UPMHP), on use of outpatient mental health services by Medicaid beneficiaries with schizophrenia. Data were collected through interviews with the same group of Medicaid schizophrenic beneficiaries. A pre/post comparison with a contemporaneous control group examined the impact of the program on type of outpatient services used by beneficiaries. The results indicate a greater reliance on medically-oriented outpatient mental health services in treatment of beneficiaries under the UPMHP. Medicaid beneficiaries with schizophrenia in the UPMHP group received relatively fewer day treatment visits, but relatively more medication visits and individual therapy visits over the first 3 1/2 years of the program.

Adult↗