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Biomedical subjects

J Liu

Publications and source records attributed to J Liu.

At least 181 records · Page 10Linked to original sources
PubMed2003

An effective method for axillary bud culture and RAPD analysis of cloned plants in tetraploid black locust.

An efficient micropropagation technique by axillary bud multiplication was established for cloning tetraploid black locust tree (Robinia pseudoacacia L.). The result showed that the optimal medium for shoot multiplication and elongation was Murashige and Skoog (MS) medium supplemented with 0.5 mg/l 6-benzylaminopurine in combination with 0.5 mg/l kinetin and 0.1 mg/l 1-naphthaleneacetic acid. The best medium for rooting was half-strength MS medium with 0.25 mg/l indole-3-butyric acid. In the present report, we examined the genetic fidelity of the micropropagated plants by the randomly amplified polymorphic DNA (RAPD) method with 25 primers. The cloned plants of tetraploid black locust showed complete stability.

Animal Feed↗
PubMed2003

Paclitaxel induces nucleolar enlargement in dorsal root ganglion neurons in vivo reducing oxaliplatin toxicity.

Paclitaxel and oxaliplatin are promising drugs for combination trials but both induce peripheral neurotoxicity. To investigate this toxicity, 10-week-old female Wistar rats were given single intraperitoneal doses of paclitaxel and oxaliplatin, alone or in combination. Neurotoxicity was assessed by L5 dorsal root ganglion morphometry and H-reflex-related sensory nerve conduction velocity. Platinum concentrations in dorsal root ganglia and plasma were measured by inductively coupled plasma mass spectrometry. Dorsal root ganglion nucleolus size was significantly increased following single doses of paclitaxel of 10 and 20 mg kg(-1) at 24 h and 6 days (P<0.02). In contrast, dorsal root ganglion nucleolus size was significantly decreased following single doses of oxaliplatin ranging from 3 to 30 mg kg(-1) at time points ranging from 2 h to 14 days. Sensory nerve conduction velocity was altered after a single dose of oxaliplatin but not after paclitaxel. In combination with oxaliplatin, paclitaxel did not alter the plasma pharmacokinetics or dorsal root ganglion accumulation of oxaliplatin-derived platinum. However, prior paclitaxel inhibited oxaliplatin-induced reductions of dorsal root ganglion nucleolar diameter (P<0.02). Sensory nerve conduction velocity was reduced after oxaliplatin alone (P&<0.05) but unchanged when paclitaxel was given before oxaliplatin. In conclusion, paclitaxel induces nucleolar enlargement in dorsal root ganglion neurons after pharmacologically relevant doses in vivo and reduces oxaliplatin nucleolar damage and neurotoxicity.

Age Factors↗
PubMed2003

Characterization and utilization of two novel anti-erbB-2 monoclonal antibodies in detection of soluble ErbB-2 for breast cancer prognosis.

We generated three anti-ErbB-2 monoclonal antibodies (mAbs) by using surface-epitope masking method (SEM method). They were characterized and shown to recognize the extracellular domain (ECD) of ErbB-2 specifically. In order to detect ErbB-2 in the sera of breast cancer patients, we used two of them: A18 and A21 to develop a sandwich enzyme-linked immunosorbent assay (ELISA). Sera from 10 of 57 patients (18%) and two of 142 controls (1.4%) had soluble ErbB-2 values higher than the cut-off level (30 ng/ml). The number of cancer patients with elevated sera ErbB-2 levels was significantly greater than that of the control group (P<0.005). Besides, three of the four cancer patients with metastasis (75%) had elevated serum ErbB-2 levels. We also purified ErbB-2 by A18-conjugated immunoaffinity chromatography and used it as the standard in the sandwich ELISA. Based on our preliminary clinical data, we came to the conclusion that both A18 and A21 could possibly be used in the prognosis of breast cancer.

3T3 Cells↗
PubMed2003

Bile acids for viral hepatitis.

BACKGROUND: The viral hepatitides are common causes of liver diseases globally. Trials have assessed bile acids for patients with viral hepatitis, but no consensus was reached regarding their usefulness. OBJECTIVES: To assess the beneficial and harmful effects of bile acids for viral hepatitis. SEARCH STRATEGY: Searches were performed of the trial registers of The Cochrane Hepato-Biliary Group (September 2002), The Cochrane Library (Issue 2, 2002), MEDLINE (September 2002), EMBASE (September 2002), and The Chinese Biomedical Database (April 2001). SELECTION CRITERIA: Randomised clinical trials comparing any dose or duration of bile acids versus placebo or no intervention for viral hepatitis were included, irrespective of language, publication status, or blinding. DATA COLLECTION AND ANALYSIS: Two reviewers extracted the data independently. The methodological quality of the trials was evaluated with respect to generation of the allocation sequence, allocation concealment, double blinding, and follow-up. The outcomes were presented as relative risks (RR) or weighted mean differences (WMD) with 95% confidence intervals (CI). MAIN RESULTS: We identified 27 randomised trials of bile acids for hepatitis B or C; none were of high methodological quality. In one trial, ursodeoxycholic acid (UDCA) versus placebo for acute hepatitis B significantly reduced the risk of hepatitis B surface antigen positivity at the end of treatment and serum HBV DNA level at the end of follow-up. In another trial, UDCA versus no intervention for chronic hepatitis B significantly reduced the risk of having abnormal serum transaminase activities at the end of treatment. Twenty-five trials compared bile acids (21 trials UDCA; four trials tauro-UDCA) versus placebo or no intervention with or without co-interventions for chronic hepatitis C. Bile acids did not significantly reduce the risk of having detectable serum HCV RNA (RR 0.99, 95% CI 0.91 to 1.07), cirrhosis, or portal and periportal inflammation score at the end of treatment. Bile acids significantly decreased the risk of having abnormal serum alanine aminotransferase activity at the end of treatment (RR 0.82, 95% CI 0.76 to 0.90) and follow-up (RR 0.91, 95% CI 0.85 to 0.98). Bile acids significantly increased the Knodell score (WMD 0.20, 95% CI 0.08 to 0.31) at the end of treatment. No severe adverse events were reported. We did not identify trials including patients with hepatitis A, acute C, D, or E. REVIEWER'S CONCLUSIONS: Bile acids lead to a significant improvement in serum transaminase activities in hepatitis B and C. There is insufficient evidence either to support or to refute effects on viral markers, mortality, incidence of cirrhosis, or liver histology. Trials with high methodological quality are required.

Antiviral Agents↗
PubMed2003

Automatic prediction of protein function.

Most methods annotating protein function utilise sequence homology to proteins of experimentally known function. Such a homology-based annotation transfer is problematic and limited in scope. Therefore, computational biologists have begun to develop ab initio methods that predict aspects of function, including subcellular localization, post-translational modifications, functional type and protein-protein interactions. For the first two cases, the most accurate approaches rely on identifying short signalling motifs, while the most general methods utilise tools of artificial intelligence. An outstanding new method predicts classes of cellular function directly from sequence. Similarly, promising methods have been developed predicting protein-protein interaction partners at acceptable levels of accuracy for some pairs in entire proteomes. No matter how difficult the task, successes over the last few years have clearly paved the way for ab initio prediction of protein function.

Computational Biology↗
PubMed2003

Lattice measurement and alloy compositions in metal and bimetallic nanoparticles.

A new reliable method for determining the lattice spacings of metallic and bimetallic nanoparticles in phase contrast high resolution electron microscopy (HREM) images was developed. In this study, we discuss problems in applying HREM techniques to single metal (Pt and Au) and bimetallic (AuPd) nanoparticles of unknown shapes and random orientations. Errors arising from particle tilt and edge effects are discussed and analysis criteria are presented to reduce these errors in measuring the lattice parameters of nanoparticles. The accuracy of an individual particle lattice measurement is limited by an effective standard deviation which depends on the size of the individual nanoparticle. For example, the standard deviation for 20-30 A Pt or Au nanoparticles is about 1.5%. To increase the accuracy in determining the lattice spacings of nanoparticles, statistical methods have to be used to obtain the average lattice spacing of an ensemble of nanoparticles. We measured approximately 100 nanoparticles with sizes in the range of 20-30 A and found that the mean lattice spacing can be determined to within 0.2%. By applying Vegard's law to the AuPd bimetallic systems we successfully detected the presence of alloying. For 30 A nanoparticles, the estimated ultimate error in determining the composition of the AuPd alloy is about 3% provided that at least 100 particles are measured. Finally, the challenges in determining the presence of more than one alloy phases in bimetallic nanoparticle systems were also discussed.

Journal Article↗
PubMed2003

In vitro detection of (S)-naproxen and ibuprofen binding to plaques in the Alzheimer's brain using the positron emission tomography molecular imaging probe 2-(1-[6-[(2-[(18)F]fluoroethyl)(methyl)amino]-2-naphthyl]ethylidene)malononitrile.

Epidemiological studies have suggested that the chronic use of non-steroidal anti-inflammatory drugs (NSAIDs) reduces the relative risk of Alzheimer's disease (AD). The possible neuroprotection by NSAIDs in AD is generally attributed to anti-inflammatory activity. An additional mode of drug action may involve anti-aggregation of beta-amyloid (Abeta) peptides by commonly used NSAIDs. We utilized in vitro competition assays, autoradiography, and fluorescence microscopy with AD brain specimens to demonstrate concentration-dependent decreases in the binding of the in vivo molecular imaging probe, 2-(1-[6-[(2-[(18)F]fluoroethyl)(methyl)amino]-2-naphthyl]ethylidene)malononitrile ([(18)F]FDDNP), against (S)-naproxen and (R)- and (S)-ibuprofen (but not diclofenac) to Abeta fibrils and ex vivo Abeta senile plaques. Conversely, in vitro amyloid dyes Congo Red and Thioflavine T were demonstrated in the same experiments not to bind to the FDDNP binding site. FDDNP and the NSAIDs that share the same binding site also exhibit anti-aggregation effects on Abeta peptides, suggesting that the shared binding site on Abeta fibrils and plaques may be a site of anti-aggregation drug action. Our results indicate for the first time the binding of select NSAIDs to plaques, specifically to the binding site of the molecular imaging probe [(18)F]FDDNP. Our understanding of the molecular requirements of FDDNP binding may help in the optimization of the Abeta anti-aggregation potency of experimental drugs. [(18)F]FDDNP has been used to image plaques in vivo with positron emission tomography (PET), and investigations into the influence of Abeta anti-aggregation on the risk-reduction effects of NSAIDs on AD could utilize [(18)F]FDDNP and PET in determining the occupancy rate of NSAIDs and experimental drugs in plaques in the living brain of AD patients.

Aged↗
PubMed2003

Performance analysis on hybrid ventilation system for residential buildings using a test house.

Hybrid ventilation system is a two-mode system that can automatically switch between passive and mechanical modes at different times of the day or season of the year. In this study various ventilation systems, including hybrid system, are used for the investigation. These systems are set up in a full-scale test house constructed in the Tohoku University, Japan. Case studies for evaluating the performance of these systems, by field studies and numerical simulations, are described. The results obtained from this study show that, the hybrid system can supplement the under-ventilation even under a milder weather condition and the airflow rate can be fixed at a certain high level, in comparison with passive system.

Air Movements↗
PubMed2003

Evidence for a putative bipolar disorder locus on 2p13-16 and other potential loci on 4q31, 7q34, 8q13, 9q31, 10q21-24, 13q32, 14q21 and 17q11-12.

Bipolar disorder (BP) is a severe and common psychiatric disorder characterized by extreme mood swings. Family, twin and adoption studies strongly support a genetic component. The mode of inheritance is complex and likely involves multiple, as yet unidentified genes. To identify susceptibility loci, we conducted a genome-wide scan with 343 microsatellite markers in one of the largest, well-characterized pedigree samples assembled to date (373 individuals in 40 pedigrees). To increase power to detect linkage, scan statistics were used to examine the logarithm of odds (lod) scores based on evidence at adjacent chromosomal loci. This analysis yielded significant evidence of linkage (genome-wide P&<0.05) for markers on 2p13-16. Standard linkage analysis was also supportive of linkage to 2p13-16 (lod=3.20), and identified several other interesting regions: 4q31 (lod=3.16), 7q34 (lod=2.78), 8q13 (lod=2.06), 9q31 (lod=2.07), 10q24 (lod=2.79), 13q32 (lod=2.2), 14q21 (lod=2.36) and 17q11-12 (lod=2.75). In this systematic, large-scale study, we identified novel putative loci for BP (on 2p13-16, 8q13 and 14q21) and found support for previously proposed loci (on 4q31, 7q34, 9q31, 10q21-24, 13q32 and 17q11-12). Two of the regions implicated in our study, 2p13-14 and 13q32, have also been linked to schizophrenia, suggesting that the two disorders may have susceptibility genes in common.

Adolescent↗
PubMed2003

Production of gamma-linolenic acid by disrupted mycelia of Mortierella isabellina.

AIMS: To optimize the production of linolenic acid by disrupted mycelia of Mortierella isabellina. METHODS AND RESULTS: Effects of incubation conditions such as incubation time, pH of reaction mixture, concentration of Mg2+ or malate and incubation temperature on production of linolenic acid were studied. The production of gamma-linolenic acid reached 224 mg g-1 dry cells when the reaction mixture was composed of 1.0 g (dry mycelial mass) of disrupted mycelia of M. isabellina, 50 ml (50 mmol l(-1)) potassium phosphate buffer supplemented with 0.312 mmol l(-1) of Mg2+ and 10 mmol l(-1) of malate, pH 7.0 and incubated at 5 degrees C for 1 day. CONCLUSIONS: Incubation temperature, concentration of Mg2+ and malate showed major effects on the increased linolenic acid production. SIGNIFICANCE AND IMPACT OF THE STUDY: This study highlights conditions for increasing gamma-linolenic acid production by cell-free mycelia of M. isabellina and an insight into rapidly gaining high production of polyunsaturated fatty acids.

Culture Media↗
PubMed2003

Improving heterologous gene expression in Aspergillus niger by introducing multiple copies of protein-binding sequence containing CCAAT to the promoter.

AIMS: To increase the expression level of heterologous gene in Aspergillus niger. METHODS AND RESULTS: Inserting multiple copies of an activator protein-binding site originally encoded in the cis-regulatory region of A. niger glucoamylase gene (glaA), CCAAT-containing sequence, into the promoter of an expression plasmid greatly enhanced the production of heterologous protein. CONCLUSION: The promoter activity was increased by the introduction of the CCAAT-containing sequence resulting in increased gene expression. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides evidence that the CCAAT-containing region of the glaA promoter of A. niger is a binding site for a positive transcriptional factor and demonstrates the possibility for improving the expression of both heterologous and endogenous genes in Aspergillus.

Aspergillus niger↗
PubMed2003

AlphaIIbbeta3-mediated outside-in signaling induced by the agonist peptide LSARLAF utilizes ADP and thromboxane A2 receptors to cause alpha-granule secretion by platelets.

The peptide LSARLAF (LSA) causes alphaIIbbeta3-dependent platelet activation that results in alpha-granule secretion and aggregation. LSARLAF-induced, alphaIIbbeta3-mediated outside-in signaling causing alpha-granule secretion and platelet aggregation was studied using washed mouse platelets. ADP receptor antagonists, enzyme inhibitors, normal platelets and platelets from mice that lack either Galphaq or thromboxane (Tx) A2 receptors were used for this investigation. The results demonstrate that LSA-induced alphaIIbbeta3-mediated signaling producing aggregation of washed platelets is mediated through the release of ADP and thromboxane, which cause alpha-granule release by mediating their effects though Galphaq and/or Gi depending on the level of LSA used to activate the platelets. Specifically, alphaIIbbeta3 elicited aggregation of washed platelets in response to a low level of LSA requires signaling through the ADP receptor P2Y1 and Galphaq, and the ADP receptor P2Y12 and Gi as well as TxA2 receptors. However, this aggregation is independent of Galphaq and TxA2 signaling in response to high LSA concentrations, but is dependent on ADP signaling through its receptor P2Y12, and therefore presumably Gi, regardless of the level of LSA used to activate the platelets. PKC function is required for ADP secretion and the subsequent signaling through P2Y12 regardless of the level of LSA used to activate the platelets. The end point of the LSA-induced alphaIIbbeta3-mediated signaling characterized in this study is alpha-granule secretion, which provides the fibrinogen required for aggregation of washed platelets.

Adenosine Diphosphate↗
PubMed2003

Effects of insulin and insulin-like growth factor-I on renin gene expression in the renal cortical cells of ovine fetuses.

Renin gene expression and insulin-like growth factor-I (IGFI) gene expression are both developmentally upregulated in the renal cortex of ovine fetuses and decline after birth. The infusion of IGFI into ovine fetuses in late gestation increases plasma renin activity and concentration. In order to determine whether there are direct effects of IGFI or insulin on renin gene expression in the kidneys of ovine fetuses, we treated the renal cortical cells of ovine fetuses with IGFI or insulin. The results showed that the responses of renal renin mRNA to IGFI or insulin treatment in vitro were dependent on the culture conditions. Renin mRNA levels were significantly elevated by IGFI or insulin if the cells were cultured in medium devoid of serum (starved) for 16-18 h before treatment. In contrast, no obvious changes in renal renin mRNA expression were observed in the cells cultured in the presence of serum (non starved) before treatment with IGFI or insulin. IGFI and insulin also significantly enhanced cAMP concentrations in the medium of the cells starved in vitro. The data suggest that IGFI and insulin can act directly on the renal cortical cells from ovine fetuses to stimulate renin mRNA expression. It is possible that IGFI and insulin stimulate renin mRNA expression by increasing cAMP concentration in the cells.

Animals↗
PubMed2003

Network-based real-time radiation monitoring system in Synchrotron Radiation Research Center.

The real-time radiation monitoring system (RMS) in the Synchrotron Radiation Research Center (SRRC) has been upgraded significantly during the past years. The new framework of the RMS is built on the popular network technology, including Ethernet hardware connections and Web-based software interfaces. It features virtually no distance limitations, flexible and scalable equipment connections, faster response time, remote diagnosis, easy maintenance, as well as many graphic user interface software tools. This paper briefly describes the radiation environment in SRRC and presents the system configuration, basic functions, and some operational results of this real-time RMS. Besides the control of radiation exposures, it has been demonstrated that a variety of valuable information or correlations could be extracted from the measured radiation levels delivered by the RMS, including the changes of operating conditions, beam loss pattern, radiation skyshine, and so on. The real-time RMS can be conveniently accessed either using the dedicated client program or World Wide Web interface. The address of the Web site is http:// www-rms.srrc.gov.tw.

Computer Communication Networks↗
PubMed2003

Prenatal drug exposure and maternal and infant feeding behaviour.

OBJECTIVE: To evaluate feeding difficulties and maternal behaviour during a feeding session with 1 month old infants prenatally exposed to cocaine and/or opiates. METHODS: The study is part of the maternal lifestyle study, which recruited 11 811 subjects at four urban hospitals, then followed 1388 from 1 to 36 months of age. Exposure to cocaine and opiates was determined by maternal interview and meconium assay. At the 1 month clinic visit, biological mothers were videotaped while bottle feeding their infants. This sample included 364 exposed to cocaine, 45 exposed to opiates, 31 exposed to both drugs, and 588 matched comparison infants. Mothers were mostly black, high school educated, and on public assistance. Videotapes were coded without knowledge of exposure status for frequency, duration and quality of infant sucking, arousal, feeding problems, and maternal feeding activity and interaction. RESULTS: No cocaine effects were found on infant feeding measures, but cocaine-using mothers were less flexible (6.29 v 6.50), less engaged (5.77 v 6.22), and had shorter feeding sessions (638 v 683 seconds). Opiate exposed infants showed prolonged sucking bursts (29 v 20 seconds), fewer pauses (1.6 v 2.2 per minute), more feeding problems (0.55 v 0.38), and increased arousal (2.59 v 2.39). Their mothers showed increased activity (30 v 22), independent of their infants' feeding problems. CONCLUSIONS: Previous concerns about feeding behaviour in cocaine exposed infants may reflect the quality of the feeding interaction rather than infant feeding problems related to prenatal exposure. However, opiate exposed infants and their mothers both contributed to increased arousal and heightened feeding behaviour.

Adult↗
PubMed2003

Identification of a locus for type I punctate palmoplantar keratoderma on chromosome 15q22-q24.

BACKGROUND: The identification of the molecular basis of disorders of keratinisation has significantly advanced our understanding of skin biology, revealing new information on key structures in the skin, such as the intermediate filaments, desmosomes, and gap junctions. Among these disorders, there is an extraordinarily heterogeneous group known as palmoplantar keratodermas (PPK), for which only a few molecular defects have been described. A particular form of PPK, known as punctate PPK, has been described in a few large autosomal dominant pedigrees, but its genetic basis has yet to be identified. AIM: Identification of the gene for punctate PPK. METHODS: Clinical examination and linkage analysis in three families with punctate PPK. RESULTS: A genomewide scan was performed on an extended autosomal dominant pedigree, and linkage to chromosome 15q22-q24 was identified. With the addition of two new families with the same phenotype, we confirmed the mapping of the locus for punctate PPK to a 9.98 cM interval, flanked by markers D15S534 and D15S818 (maximum two point lod score of 4.93 at theta = 0 for marker D15S988). CONCLUSIONS: We report the clinical and genetic findings in three pedigrees with the punctate form of PPK. We have mapped a genetic locus for this phenotype to chromosome 15q22-q24, which indicates the identification of a new gene involved in skin integrity.

Chromosome Mapping↗