PubMed Health⌕ Search

Biomedical subjects

C Liu

Publications and source records attributed to C Liu.

At least 55 records · Page 3Linked to original sources
PubMed2005

Genetic tests of biologic systems in affective disorders.

To liberate candidate gene analyses from criticisms of inexhaustiveness of examination of specific candidate genes, or incompleteness in the choice of candidate genes to study for specific neurobiological pathways, study of sizeable sets of genes pertinent to each putative pathophysiological pathway is required. For many years, genes have been tested in a 'one by one' manner for association with major affective disorders, primarily bipolar illness. However, it is conceivable that not individual genes but abnormalities in several genes within a system or in several neuronal, neural, or hormonal systems are implicated in the functional hypotheses for etiology of affective disorders. Compilation of candidate genes for entire pathways is a challenge, but can reasonably be carried out for the major affective disorders as discussed here. We present here five groupings of genes implicated by neuropharmacological and other evidence, which suggest 252 candidate genes worth examining. Inexhaustiveness of gene interrogation would apply to many studies in which only one polymorphism per gene is analyzed. In contrast to whole-genome association studies, a study of a limited number of candidate genes can readily exploit information on genomic sequence variations obtained from databases and/or resequencing, and has an advantage of not having the complication of an extremely stringent statistical criterion for association.

Bipolar Disorder↗
PubMed2005

Characteristics of vitamin C immobilized particles and sodium alginate beads containing immobilized particles.

This paper reports the properties of vitamin C encapsulated sodium alginate beads prepared by an alternative approach. The alternative encapsulation process mainly involves immobilization of vitamin C in hydrated zinc oxide layers and encapsulation of prepared immobilized particles in sodium alginate bead. The immobilization of vitamin C in hydrated zinc oxide layers was achieved by a coprecipitation process. Fourier transform infrared (FTIR) spectroscopy showed that the vitamin C was found to be stable after its immobilization. X-ray diffraction (XRD) studies revealed that anionic vitamin C molecules are adsorbed between positively charged zinc hydroxide layers with a 1:1 layer sequence, since well-defined change in basal spacing was observed. Well-defined change in surface morphology was observed by scanning electron microscopy (SEM) when vitamin C immobilized particles are encapsulated in sodium alginate bead. The biological activity of vitamin C was retained, even after its immobilization which was confirmed by 4-dihydroxy-L-phenylalanine (L-DOPA) oxidase inhibition and free radical scavenging activity studies. The release rate of vitamin C from immobilized particles and beads was sustained through an ion exchange process. A higher amount of stable vitamin C was recovered from the bead when compared to neat vitamin C itself.

Alginates↗
PubMed2005

Clinical study of recombinant adenovirus-p53 (Adp53) combined with hyperthermia in advanced cancer (a report of 15 cases).

The study was to evaluate the efficacy of the Adp53 combined with hyperthermia on advanced cancer. Fifteen patients with advanced cancer were enrolled in this clinical trial. Thirteen patients with recurrent tumours failed in conventional treatments and the two other patients with primary tumour received no treatment before they were enrolled. Recombinant adenovirus-p53 (Adp53) is a E1 substituted replication-incompetent recombinant adenovirus encoding the human wild-type p53 (wtp53) gene. The 15 patients were intra-tumourally injected with Adp53, 1x10(12)vp (virus particle) once a week, with a total of 4-8 times was given. The temperature being set hyperthermia every week 3 days after the injection of Adp53 at 43-44 degrees C using 915 MHz microwave machine for superficial tumour for 1 h or at 42-43 degrees C using 41 MHz radiofrequency machine for deep-seated tumour for 1 h. Among the 15 patients, five concurrently were added with radiotherapy and three were added with cisplatin-based chemotherapy. The treatment achieved CR in two cases, PR in four cases, SD in eight cases and PD in one case and, after the treatment, tumours of two cases disappeared and seven of the other 13 cases (54%) had low-density area (LDA) of more than 50% on CT images in tumours. In the 15 patients, no dose-limiting toxicity and adverse events were noted, except transient fever after Adp53 administration. In conclusion, Adp53 combined with hyperthermia was safe and effective in patients with advanced cancer and p53 gene therapy was potential to thermosensitize in advanced cancer.

Adenoviruses, Human↗
PubMed2005

Effect of genetic selection on MyoD and myogenin expression in turkeys with different growth rates.

Skeletal muscle development requires the ordered expression of specific myogenic regulatory factors, which include MyoD, Myf5, myogenin, and MRF4. The MyoD and Mrf5 factors are required for the determination of myoblasts, whereas myogenin and MRF4 play a pivotal role in terminal differentiation. In the current study, males and females of a turkey genetic line selected only for increased 16-wk BW (F line) and an unselected randombred control (RBC2 line) from which the F line was developed were used to investigate the developmental expression of MyoD and myogenin mRNA in embryonic pectoralis major muscle and myogenic satellite cells. Pectoralis major muscle was isolated at embryonic d (ED) 14, 16, 18, 20, 22, and 24. The mRNA levels of MyoD and myogenin were measured using a real-time quantitative polymerase chain reaction method. Both MyoD and myogenin expression declined during embryonic development. The decrease in MyoD expression started at ED 16 for the F line and at ED 18 for the RBC2 line for both sexes. Myogenin expression in both lines began to decline at ED 14. The F line males had lower myogenin expression at ED 14, 16, and 18 than the RBC2 line males, which was similar for the F line females compared with the RBC2 line females except there was no significant difference at ED 18. The RBC2 line males had greater expression than the females for myogenin at ED 16 and 18 for the RBC2 line. Proliferating myogenic satellite cells in both lines and sexes expressed low levels of MyoD and myogenin. After the initiation of differentiation in both lines and sexes, there was a sharp surge in MyoD expression at 24 h followed by a decrease at 48 h and then an increase in expression through 72 or 96 h of differentiation. There were line and sex differences in myogenin expression during the differentiation process. These data are suggestive of growth- and sex-related differences in the expression of myogenic regulatory factors key to muscle cell proliferation and differentiation, which will affect muscle growth rate.

Animals↗
PubMed2005

Molecular cloning, localization and circadian expression of chicken melanopsin (Opn4): differential regulation of expression in pineal and retinal cell types.

The avian retina and pineal gland contain autonomous circadian oscillators and photo-entrainment pathways, but the photopigment(s) that mediate entrainment have not been definitively identified. Melanopsin (Opn4) is a novel opsin involved in entrainment of circadian rhythms in mammals. Here, we report the cDNA cloning of chicken melanopsin and show its expression in retina, brain and pineal gland. Like the melanopsins identified in amphibians and mammals, chicken melanopsin is more similar to the invertebrate retinaldehyde-based photopigments than the retinaldehyde-based photopigments typically found in vertebrates. In retina, melanopsin mRNA is expressed in cells of all retinal layers. In pineal gland, expression was strong throughout the parenchyma of the gland. In brain, expression was observed in a few discrete nuclei, including the lateral septal area and medial preoptic nucleus. The retina and pineal gland showed distinct diurnal expression patterns. In pineal gland, melanopsin mRNA levels were highest at night at Zeitgeber time (ZT) 16. In contrast, transcript levels in the whole retina reached their highest levels in the early morning (ZT 0-4). Further analysis of melanopsin mRNA expression in retinal layers isolated by laser capture microdissection revealed different patterns in different layers. There was diurnal expression in all retinal layers except the ganglion cell layer, where heavy expression was localized to a small number of cells. Expression of melanopsin mRNA peaked during the daytime in the retinal pigment epithelium and inner nuclear layer but, like in the pineal, at night in the photoreceptors. Localization and regulation of melanopsin mRNA in the retina and pineal gland is consistent with the hypothesis that this novel photopigment plays a role in photic regulation of circadian function in these tissues.

Amino Acid Sequence↗
PubMed2005

Studies into using manure in a biorefinery concept.

Animal manure is an underutilized biomass resource containing a large amount of organic carbon that is often wasted with the existing manure disposal practices. A research project funded by the US Department of Energy explored the feasibility of using manure via the sugar platform in a biorefinery, converting the carbon from fiber to biochemicals. The results showed that (1) fiber was the major component of manure dry material making up approx 50%, 40%, and 36% of the dry dairy, swine, and poultry manure material, respectively; within dairy manure, more than 56% of the dry matter was in particles larger than 1.680 mm; (2) in addition to being a carbon source, manure could provide a variety of nutrient for fungi T. reesei and A. phoenicis to produce cellulase; (3) the hemicellulose component in the manure fiber could be readily converted to sugar through acid hydrolysis; while concentrated acid decrystallization treatment was most effective in manure cellulose hydrolysis; (4) purification and separation was necessary for further chemical conversion of the manure hydrolysate to polyols through hydrogenation; and (5) the manure utilization strategy studied in this work is currently not profitable.

Agriculture↗
PubMed2005

Distribution and carbohydrate structures of high molecular weight glycoproteins, MUC1 and MUCX, in bovine milk.

High molecular weight glycoproteins, MUC1 and MUCX, originating from bovine milk, were compared with regard to their distribution in milk fat and skim milk fractions and for presence of carbohydrate structures. Polymorphic MUC1, which migrated into 6% resolving SDS-PAGE gels, was found in both milk fat globule membrane and skim milk phases of bovine milk. In contrast, MUCX, appearing as a non-polymorphic single band in 3% polyacrylamide stacking gels, was present only in the skim milk fraction. Peptide-N-glycosidase F digestion studies indicated that MUC1 and MUCX possessed N-glycans with MUC1 containing more N-glycans than MUCX. Exoglycosidase digestion studies revealed the existence of abundant terminal sialic acid residues in both MUC1 and MUCX. Lectin-binding studies showed that MUCX likely possessed more complex carbohydrate structures than MUC1. The complex carbohydrate structures carried by both MUC1 and MUCX suggest that they may have potential to bind a wide spectrum of pathogenic microorganisms. If that proves to be the case in vivo, such structures could have a role in preventing or reducing some infectious diseases.

Amino Acids↗
PubMed2005

Concentration and detection of SARS coronavirus in sewage from Xiao Tang Shan Hospital and the 309th Hospital of the Chinese People's Liberation Army.

A worldwide outbreak of severe acute respiratory syndrome (SARS) had been reported. Over 8439 SARS cases and 812 SARS-related deaths were reported to the World Health Organization from 32 countries around the world up to 5 July 2003. The mechanism of transmission of SARS-CoV has been limited only to close contacts with patients. Attention was focused on possible transmission by the sewage system because laboratory studies showed that patients excreted coronavirus RNA in their stools in Amoy Gardens in Hong Kong. To explore whether the stool of SARS patients or the sewage containing the stool of patients would transmit SARS-CoV or not, we used a style of electropositive filter media particle to concentrate the SARS-CoV from the sewage of two hospitals receiving SARS patients in Beijing, as well as cell culture, semi-nested RT-PCR and sequencing of genes to detect and identify the viruses from sewage. There was no live SARS-CoV detected in the sewage in these assays. The nucleic acid of SARS-CoV was found in the sewage before disinfection from both hospitals by PCR. After disinfection, SARS-CoV RNA could be detected from some samples from the 309th Hospital of the Chinese People's Liberation Army, but not from Xiao Tang Shan Hospital after disinfection. In this study, we found that the virus can survive for 14 days in sewage at 4 degrees C, 2 days at 20 degrees C, and its RNA can be detected for 8 days though the virus had been inactivated. In conclusion, this study demonstrates that the RNA of SARS-CoV could be detected from the concentrates of sewage of both hospitals receiving SARS patients before disinfection and occasionally after disinfection though there was no live SARS-CoV; thus much attention should be paid to the treatment of stools of patients and the sewage of hospitals receiving SARS patients.

Bacteriophages↗
PubMed2004

Chemical and biological characterization of a polysaccharide biological response modifier from Aloe vera L. var. chinensis (Haw.) Berg.

Three purified polysaccharide fractions designated as PAC-I, PAC-II, and PAC-III were prepared from Aloe vera L. var. chinensis (Haw.) Berg. by membrane fractionation and gel filtration HPLC. The polysaccharide fractions had molecular weights of 10,000 kDa, 1300 kDa, and 470 kDa, respectively. The major sugar residue in the polysaccharide fractions is mannose, which was found to be 91.5% in PAC-I, 87.9% in PAC-II, and 53.7% in PAC-III. The protein contents in the polysaccharide fractions was undetectable. NMR study of PAC-I and PAC-II demonstrated the polysaccharides shared the same structure. The main skeletons of PAC-I and PAC-II are beta-(1-->4)-D linked mannose with acetylation at C-6 of manopyranosyl. The polysaccharide fractions stimulated peritoneal macrophages, splenic T and B cell proliferation, and activated these cells to secrete TNF-alpha, IL-1 beta, INF-gamma, IL-2, and IL-6. The polysaccharides were nontoxic and exhibited potent indirect antitumor response in murine model. PAC-I, which had the highest mannose content and molecular weight, was found to be the most potent biological response modifier of the three fractions. Our results suggested that the potency of aloe polysaccharide fraction increases as mannose content and molecular weight of the polysaccharide fraction increase.

Aloe↗
PubMed2004

Nanosecond and femtosecond laser ablation of brass: particulate and ICPMS measurements.

Femtosecond and nanosecond lasers were compared for ablating brass alloys. All operating parameters from both lasers were equal except for the pulse duration. The ablated aerosol vapor was collected on silicon substrates for particle size measurements or sent into an inductively coupled plasma mass spectrometer. The diameters and size distribution of particulates were measured from scanning electron microscope (SEM) images of the collected ablated aerosol. SEM measurements showed that particles ablated using nanosecond pulses were single spherical entities ranging in diameter from several micrometers to several hundred nanometers. Primary particles ablated using femtosecond ablation were approximately 100 nm in diameter but formed large agglomerates. ICPMS showed enhanced signal intensity and stability using femtosecond compared to nanosecond laser ablation.

Journal Article↗
PubMed2004

Methotrexate for ankylosing spondylitis.

BACKGROUND: Ankylosing spondylitis (AS) is a chronic inflammatory disease of unknown cause, characterized by sacroiliitis and spondylitis. To date, treatment of AS has been limited to the alleviation of symptoms, mainly using non-steroidal anti-inflammatory drugs (NSAIDs). For patients refractory or intolerant to NSAIDs, the disease modifying antirheumatic drugs (DMARDs) have been used as a second line approach. Methotrexate (MTX) is currently one of the most widely used DMARDs and its efficacy in rheumatoid arthritis (RA) has been confirmed (Suarez-Almazor 2003). There is uncertainty whether MTX works in the treatment of AS. OBJECTIVES: To evaluate the efficacy and toxicity of methotrexate in the treatment of ankylosing spondylitis. SEARCH STRATEGY: Relevant randomised and quasi-randomised trials in any language were sought using the following sources: CENTRAL (Cochrane Central Register of Controlled Trials, Issue 2, 2003), MEDLINE (1966 to June Week 4 2003), EMBASE (1980 to 2003 Week 26), CINAHL (1982 to June Week 3 2003) and the reference section of retrieved articles. SELECTION CRITERIA: We evaluated randomised and quasi-randomised trials examining the efficacy of methotrexate on AS. DATA COLLECTION AND ANALYSIS: Unblinded trial reports were reviewed independently by two reviewers according to the selection criteria. Disagreements on the inclusion of the studies were resolved, where necessary, by recourse to a third reviewer. The methodological quality of included trials were independently assessed by the same reviewers on randomization, concealment, blindness (participants, care providers and outcome investigators), description of withdrawals and drop-outs and intention-to-treat analysis. The same reviewers independently entered the data extracted from the included trials, using RevMan's double entry facility. In the absence of significant heterogeneity, results were combined using weighted mean difference or standardised mean difference for continuous data, and relative risk for dichotomous data. MAIN RESULTS: Two trials met the inclusion criteria. Altan 2001compared naproxen plus MTX (7.5 mg/week orally) with naproxen alone and Roychowdhury 2002 compared MTX (10 mg/week orally) with placebo. The duration of the trials were 12 months and 24 weeks, respectively. They assessed different outcomes except for C-reactive protein (CRP). The included trials treated a total of 81 patients and assessed more than 10 outcomes relevant to the review, covering function, pain, peripheral arthritis/enthesitis, morning stiffness, patient and physician global assessment, CRP and erythrocyte sedimentation rate (ESR). No significant difference between intervention groups was found favouring MTX over no MTX. No serious side effect was reported in either trial. REVIEWERS' CONCLUSIONS: There was no statistically significant benefit of MTX in the examined outcomes for AS patients. High quality, larger sample and longer period of randomized controlled trials (possibly with higher dosage of MTX) are needed to verify the uncertainty about the efficacy and toxicity of MTX for the treatment of AS.

Antirheumatic Agents↗
PubMed2004

Alterations of N-ethylmaleimide-sensitive atpase following transient cerebral ischemia.

Neuronal repair following injury requires recruitment of large amounts of membranous proteins into synaptic and other cell membranes, which is carried out by the fusion of transport vesicles to their target membranes. A critical molecule responsible for assemblage of membranous proteins is N-ethylmaleimide-sensitive factor (NSF) which is an ATPase. To study whether NSF is involved in ischemic neurological deficits and delayed neuronal death, we investigated alterations of NSF after transient cerebral ischemia by means of biochemical methods, as well as confocal and electron microscopy. We found that transient cerebral ischemia induced depletion of free NSF and concomitantly relocalization of NSF into the Triton X-100-insoluble fraction including postsynaptic densities in CA1 neurons during the postischemic period. The NSF alterations are accompanied by accumulation of large quantities of intracellular vesicles in CA1 neurons that are undergoing delayed neuronal death after transient cerebral ischemia. Therefore, permanent depletion of free NSF and relocalization of NSF into the Triton X-100-insoluble fraction may disable the vesicle fusion machinery necessary for repair of synaptic injury, and ultimately leads to synaptic dysfunction and delayed neuronal death in CA1 neurons after transient cerebral ischemia.

Adenosine Triphosphatases↗
PubMed2004

Gene transfer of interleukin-4 delays acute rejection of splenic allografts in rats.

Spleen transplantation is the treatment of choice for some diseases, such as hemophilia A. However, the risk and intensity of rejection after spleen transplantation is greater and more difficult to control than other types of transplant. In the present study, we demonstrated that perfusion of IL-4 expression plasmids into donor spleens pretransplantation led to overexpression of IL-4 and downregulation of IFN-gamma in situ, associated with delayed acute rejection of the allograft. Gene transfer of IL-4 may represent a potential therapeutic approach to induce tolerance to splenic allografts.

Animals↗
PubMed2004

Administration of tolerogenic dendritic cells induced by interleukin-10 prolongs rat splenic allograft survival.

The risk and intensity in splenic graft rejection are greater than in other types of transplants, because the spleen is the largest peripheral lymphoid organ and the immunosuppressive drugs administered can cause splenic dysfunction. In this study, we demonstrate that intravenous injection of interleukin-10-treated donor-type dendritic cells into recipient rats prolongs the survival of splenic allografts. Although the mechanisms are not clear, the induction of tolerance to grafted spleens seems to rely mainly on blockage of expression of the costimulatory molecule CD86, by interleukin-10, leading to enhanced apoptosis of allospecific T cells by immature and tolerogenic dendritic cells. Administration of tolerogenic cells induced by interleukin-10 may thus represent a useful approach for protection of splenic allografts. Further study is required to investigate the operative pathways and to optimize the strategy targeting dendritic cells to induce tolerance in splenic allografts.

Animals↗
PubMed2004

Analysis of cellular structure by light scattering measurements in a new cytometer design based on a liquid-core waveguide.

The results of applying a novel microfluidic optical cytometer to generate and observe the light scattered from biological cells over a wide range of angles are presented. This cytometer incorporates a waveguide that increases the intensity of the scattered light to the extent that an inexpensive digital camera can be used to detect the light over a large solid angle. This device was applied to yeast cells and latex beads and experimental data were compared with the results of a finite difference time-domain (FDTD) method of simulation. The simulated scattering patterns were calculated from reported values of optical parameters and are in good qualitative agreement with experiment. It is demonstrated that this system could be used to acquire information on the microstructure and potentially the nanostructure of cells.

Journal Article↗