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Biomedical subjects

Ting Wang

Publications and source records attributed to Ting Wang.

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

Remarkable reduction of irreversible fouling and improvement of the permeation properties of poly(ether sulfone) ultrafiltration membranes by blending with pluronic F127.

Hydrophilic modification of ultrafiltration membranes was achieved through blending of Pluronic F127 with poly(ether sulfone) (PES). The chemical composition and morphology changes of the membrane surface were confirmed by water contact angle, X-ray photoelectron spectroscopy, scanning electron microscopy, and protein adsorption measurements. The decreased static water contact angle with an increase in the Pluronic F127 content indicated an increase of surface hydrophilicity. XPS analysis revealed enrichment of PEO segments of Pluronic F127 at the membrane surface. The apparent protein adsorption amount decreased significantly from 56.2 to 0 microg/cm(2) when the Pluronic F127 content varied from 0% to 10.5%, which indicated that the blend membrane had an excellent ability to resist protein adsorption. The ultrafiltration experiments revealed that the Pluronic F127 content had little influence on the protein rejection ratio and pure water flux. Most importantly, at a high Pluronic F127 content membrane fouling, especially irreversible fouling, has been remarkably reduced. The flux recoveries of blend membranes reached as high as 90% after periodic cleaning in three cycles.

Ether↗
PubMed2005

Identifying the conserved network of cis-regulatory sites of a eukaryotic genome.

A major focus of genome research has been to decipher the cis-regulatory code that governs complex transcriptional regulation. We report a computational approach for identifying conserved regulatory motifs of an organism directly from whole genome sequences of several related species without reliance on additional information. We first construct phylogenetic profiles for each promoter, then use a BLAST-like algorithm to efficiently search through the entire profile space of all of the promoters in the genome to identify conserved motifs and the promoters that contain them. Statistical significance is estimated by modified Karlin-Altschul statistics. We applied this approach to the analysis of 3,524 Saccharomyces cerevisiae promoters and identified a highly organized regulatory network involving 3,315 promoters and 296 motifs. This network includes nearly all of the currently known motifs and covers >90% of known transcription factor binding sites. Most of the predicted coregulated gene clusters in the network have additional supporting evidence. Theoretical analysis suggests that our algorithm should be applicable to much larger genomes, such as the human genome, without reaching its statistical limitation.

Algorithms↗
PubMed2005

Validation of HPLC analysis method of a novel antihypertensive agent MS23 in rat plasma.

MS23 is a vasodilator with unique dual action pharmacological profile to inhibit type 4 PDE and antagonize L-type calcium channels. We validated an analytical protocol for MS23 in rat plasma using high performance liquid chromatography (HPLC). A C18 column and a phosphate/acetonitrite buffer were used for chromatographic separation. UV detection was performed at 307 nm. The calibration curve for MS23 was linear in the range from 50 to 10,000 ng/ml. The limit of quantification (LOQ) was 50 ng/ml. The results demonstrate that the method has linearity (R = 0.9989), specificity, and acceptable precision/accuracy. This method is simple, economic, and sufficient for in vivo pharmacokinetic studies on the compound.

Animals↗
PubMed2005

The effect of pinealectomy on scoliosis development in young nonhuman primates.

STUDY DESIGN: Prospective study on pinealectomy in primates. OBJECTIVE: To evaluate whether pinealectomy in a bipedal nonhuman primate model will result in the development of scoliosis. SUMMARY OF BACKGROUND DATA: Pinealectomy in newborn chickens consistently resulted in scoliosis development. Published data suggest that the surgical removal of the pineal, loss of melatonin secretion, and a bipedal posture are important elements in the development of scoliosis in lower animal models. METHOD: There were 18 rhesus monkeys between 8 and 11 months old that underwent pineal excision. All monkeys were kept in a regulated 12-hour light-dark cycle. Monthly radiographs assessed scoliosis development. Completeness of pineal excision was assessed by measurement of a major metabolite of melatonin in the urine, 6-sulfatoxymelatonin, using an enzyme-linked immunosorbent assay assessed. RESULTS: Mean follow-up was 28 months (range 10-41). Seven monkeys died prematurely, and 11 survived to date; the data from those that died could still be used, although follow-up was shortened. At the latest follow-up or death, scoliosis did not develop in any of the monkeys. Urinary 6-sulfatoxymelatonin measurements revealed 3 patterns. Group 1 consisted of 10 monkeys, which showed definite evidence of complete pineal excision. Group 2 consisted of an uncertain group of 2 monkeys in which the nighttime melatonin level is slightly high. Group 3 consisted of 6 monkeys that had incomplete pineal excision or ectopic melatonin production. CONCLUSIONS: To our knowledge, this is the first report of pinealectomy in nonhuman primates. Of the 18 monkeys, 10 had a loss of melatonin secretion, for a mean of 29 months after surgery. Because none of the monkeys had scoliosis develop, this study strongly suggests that the possible etiologic factors producing idiopathic scoliosis in lower animals are different from primates, and findings in lower animals cannot necessarily be extrapolated to human beings.

Animals↗
PubMed2005

Hepatitis C virus core protein inhibits mitochondrial electron transport and increases reactive oxygen species (ROS) production.

Hepatitis C infection causes a state of chronic oxidative stress, which may contribute to fibrosis and carcinogenesis in the liver. Previous studies have shown that expression of the HCV core protein in hepatoma cells depolarized mitochondria and increased reactive oxygen species (ROS) production, but the mechanisms of these effects are unknown. In this study we examined the properties of liver mitochondria from transgenic mice expressing HCV core protein, and from normal liver mitochondria incubated with recombinant core protein. Liver mitochondria from transgenic mice expressing the HCV proteins core, E1 and E2 demonstrated oxidation of the glutathione pool and a decrease in NADPH content. In addition, there was reduced activity of electron transport complex I, and increased ROS production from complex I substrates. There were no abnormalities observed in complex II or complex III function. Incubation of control mitochondria in vitro with recombinant core protein also caused glutathione oxidation, selective complex I inhibition, and increased ROS production. Proteinase K digestion of either transgenic mitochondria or control mitochondria incubated with core protein showed that core protein associates strongly with mitochondria, remains associated with the outer membrane, and is not taken up across the outer membrane. Core protein also increased Ca(2+) uptake into isolated mitochondria. These results suggest that interaction of core protein with mitochondria and subsequent oxidation of the glutathione pool and complex I inhibition may be an important cause of the oxidative stress seen in chronic hepatitis C.

Animals↗
PubMed2005

T-jump infrared study of the folding mechanism of coiled-coil GCN4-p1.

Partially folded intermediates have been frequently observed in equilibrium and kinetic protein folding studies. However, folding intermediates that exist at the native side of the rate-limiting step are rather difficult to study because they often evade detection by conventional folding kinetic methods. Here, we demonstrated that a laser-induced temperature-jump method can potentially be used to identify the existence of such post-transition or hidden intermediates. Specifically, we studied two cross-linked variants of GCN4-p1 coiled-coil. The GCN4 leucine zipper has been studied extensively and most of these studies have regarded it as a two-state folder. Our static circular dichroism and infrared data also indicate that the thermal unfolding of these two monomeric coiled-coils can be adequately described by an apparent two-state model. However, their temperature-jump-induced relaxation kinetics exhibit non-monoexponential behavior, dependent upon sequence and temperature. Taken together, our results support a folding mechanism wherein at least one folding intermediate populates behind the main rate-limiting step.

Basic-Leucine Zipper Transcription Factors↗
PubMed2005

[Evaluation and treatment of congenital scoliosis with split cord malformation].

OBJECTIVE: To discuss the diagnosis and surgical treatment of congenital scoliosis (CS) with split cord malformation (SCM). METHODS: From May 1999 to June 2004, 353 cases of CS were admitted, and 58 cases were diagnosed CS combined with SCM via myelography and (or) CTM. According to Pang's classification for SCM, patients were divided into type I SCM and type II SCM. Two cases gave up operation, and surgeries were performed in 56 patients. Except that one case with arachnoid cyst underwent intraspinal exploration, all other 55 cases underwent spinal correction without dealing with the intraspinal abnormalities. Clinical manifestation, radiological findings, operative methods and results were retrospectively analyzed in this paper. RESULTS: There were 11 patients (19%) with type I SCM and 47 patients (81%) with type II SCM. In the 56 cases who had surgical treatment, the Cobb angle in the patients with type I SCM (11 cases) was (60 +/- 25) degrees, and in type II SCM (45 cases) was (67 +/- 21) degrees pre-operation. The Cobb angle in type I SCM was (29 +/- 13) degrees and in type II SCM was (39 +/- 19) degrees post-operation, with the correction rate (51 +/- 17)% and (41 +/- 24)% respectively. No statistic differences were found between both types. And there were no new neurological deficits in both groups after the spinal correction operation. After average 17.3 months (4-59 months) follow-up, the correction loss was (6 +/- 10) degrees, (5 +/- 8) degrees in 7 patients with type I SCM and (6 +/- 10) degrees in 19 patients with type II SCM. There was no statistic difference in correction loss between both types. In the follow-up, the neurological symptoms and signs of the patients were stable. CONCLUSION: Considering the incidence of intraspinal anomalies in patients with congenital scoliosis, intraspinal examination via myelography, CTM or MRI should be performed prior to spinal correction surgery. For congenital scoliosis with type I SCM, the bone spur need not be excised before spinal correction if there is no signs of spinal cord tethered and the bone spur locate in the middle of the split cord where there are much space to accommodate it. For congenital scoliosis with type II SCM, if there are no progressive neurological manifestations, the split cord in the single tubular can tolerate the manipulation of spinal correction as the normal spinal cord.

Adolescent↗
PubMed2005

Melatonin enhances antinociceptive effects of delta-, but not mu-opioid agonist in mice.

This present study examines the effect of melatonin on antinociceptive action induced by opioid agonists in mice using the tail-flick test. When injected either by intraperitoneal (i.p.) (1, 5, 25 mg/kg) or by intracerebroventricular (i.c.v.) (0.25, 0.5, 1 mg/kg) routes, melatonin significantly enhanced the delta-opioid agonist deltorphin I induced antinociception, but not mu-opioid agonist endomorphin-1. Further investigation showed that i.c.v. luzindole (0.5 mg/kg) (an antagonist of melatonin receptor) significantly antagonized the enhanced antinociceptive effect of i.c.v. melatonin. These results demonstrated that melatonin can specifically enhance the antinociception induced by specific opioid receptor agonist (i.e., delta opioid agonist) acting on melatonin receptor and that melatonin may have augmentation effect on analgesia with delta-, but not mu-opioid agonists in mice.

Analgesics, Opioid↗
PubMed2005

[The operation treatment for severe and rigid idiopathic scoliosis].

OBJECTIVE: To discuss the operation treatment for the severe and rigid idiopathic scoliosis. METHODS: The clinical data of 24 patients with severe and rigid idiopathic scoliosis, 15 females and 9 males, with an average age of 17 (12 approximately 20) who had undergone operations from June 1999 to June 2003 were analyzed retrospectively. The patients were classified according to PUMC operative classification systerm, including 16 cases of type Ia, 2 cases of type Ib, 3 cases of type IIb2, and 1 case of types IIb1, IIc2, and IIc3 each. The average standing coronal Cobb angle was 98 degrees (80 degrees to 117 degrees ) and the average flexibility rate of the major curves was 20.8% (5% to 29.5%) before operation. Fifteen cases had sagittal deformities. Bone fusion was performed on all the cases according to the PUMC classification principles. 17 cases received anterior spinal release with posterior correction by two stages, and 2 cases by one stage. 5 cases received one-stage posterior correction. All the patients were followed up for 12 approximately 30 months (18 months on average). RESULTS: The mean standing coronal Cobb angle of the major curves was reduced to 58 degrees (32 degrees to 100 degrees ) after operation with a correction rate of 41.0% (10.9% to 61.0%). The results of sagittal plane correction were satisfying. The mean Cobb angle of the major curves at the final follow up was 63 degrees (31 degrees to 104 degrees ), and the mean lost was 5 degrees (0 degrees to 10 degrees ). One case had to undergo revision surgery because of hook displacement. One case had steel wire broken but without neurological symptoms and only needed observation. No pseudoarthrosis and decompensation occurred. CONCLUSION: Compared with vertebral osteotomy for the correction of scoliosis, the anterior spinal release combined with posterior correction and simple posterior correction have the advantages of low risk, less blood loss, and low infection rate. They can be used effectively and safely for the correction of idiopathic severe and rigid idiopathic scoliosis. The key points for the surgical procedures are appropriate correction and recovery of the balances of the coronal and sagittal planes.

Adolescent↗
PubMed2005

Maximins S, a novel group of antimicrobial peptides from toad Bombina maxima.

Amphibian skin secretions are rich in antimicrobial peptides acting as important components of innate defense system against invading microorganisms. A novel type of peptide, designated as maximin S, was deduced by random sequencing of 793 clones from a constructed Bombina maxima skin cDNA library. The putative primary structures of maximin S peptides can be grouped into five species, in which maximin S1 has 14 amino acid residues and the rest of maximin S peptides (S2-S5) all have 18 amino acid residues. Unlike most of the amphibian antimicrobial peptides so far identified, the newly characterized four maximin S precursors are composed of maximin S1 and different combinations of tandem repeated maximin S2-S5 linked by internal peptides. Except maximin S1, the predicted secondary structures of maximin S2-S5 show a similar amphipathic alpha-helical structure. MALDI-TOF mass spectrometry analysis of partially isolated skin secretions of the toad indicates that most of the deduced maximin S peptides are expressed. Two deduced maximin S peptides (S1, S4) were synthesized and their antimicrobial activities were tested. Maximin S4 only had an antibiotic activity against mycoplasma and had no antibacterial or antifungal activity toward tested strains. Maximin S1 had no activity under the same conditions.

Animals↗
PubMed2005

Inhibition of B16 melanoma growth in vivo by retroviral vector-mediated human ribonuclease inhibitor.

Human ribonuclease inhibitor (hRI) can inhibit angiogenesis by reversibly binding angiogenin, a member of the RNaseA superfamily, and by suppressing the expression of basic fibroblast growth factor (bFGF). Angiogenesis is necessary for the growth and metastasis of tumors. To study the links between hRI, angiogenesis, and melanoma growth, the hRI gene was intravenously administered to mice in a recombinant retroviral vector, and expression of the hRI gene was induced to block melanoma angiogenesis. Expression, distribution, and contribution of the target gene in mice were assayed. The results showed that the tumors of mice in the hRI treatment group grew slower with less vascularity than those of mice in control groups. The introduced hRI gene inhibited tumor growth without causing significant side effects in the animals. More hRI expression in vimentin-positive cells of the tumor than in melanoma cells suggested that mesenchymal cells in the fibrous envelope of the tumor play important roles in this gene therapy.

Angiogenesis Inhibitors↗
PubMed2005

Directed evolution for engineering pH profile of endoglucanase III from Trichoderma reesei.

The potential of cellulase has been revealed not only in biomass conversion but also in various industrial processes, including food, textiles, laundry, pulp, and paper. Due to the need for alkali-tolerant cellulase with high specific activity at alkaline pH, for example, for application in detergent industry an error-prone PCR approach was employed for enhancing the alkali-tolerant ability of endoglucanase III (EG III) from Trichoderma reesei by error-prone PCR. One mutant (N321T) which exhibited an optimal activity at pH 5.4, corresponded to a basic shift of 0.6 pH unit compared to the wild-type enzyme, was selected and characterized. In addition, two site-directed mutations, N321D and N321H, were designed to study the role of residue at position 321. As expected, the N321D mutation changed enzyme's optimal activity to pH 4.0, resulting in a large decrease in the specific activity. However, the N321H mutated enzyme was active over a broader pH range compared to the wild type, with no much change in the specific activity. These properties suggest that the residue at position 321 is important amino acid residue in determining the pH activity profile of the EG III from T. reesei.

Amino Acid Sequence↗
PubMed2005

Hepatitis C virus core protein, cytochrome P450 2E1, and alcohol produce combined mitochondrial injury and cytotoxicity in hepatoma cells.

BACKGROUND & AIMS: Alcohol consumption exacerbates liver injury in chronic hepatitis C, and enhanced mitochondrial oxidative stress is one possible mechanism. The aim of this study was to determine whether hepatitis C virus core protein and alcohol-inducible cytochrome P450 2E1 contribute to reactive oxygen species production and cytotoxicity in human hepatoma cells. METHODS: Huh-7 cells expressing core protein, cytochrome P450 2E1, or both were exposed to 0.1 mmol/L tertiary butyl hydroperoxide, tumor necrosis factor alpha, and/or 25 mmol/L ethanol. Cytotoxicity, reactive oxygen species production, glutathione content, and mitochondrial membrane potential were measured. RESULTS: Expression of core/cytochrome P450 2E1 synergistically enhanced cell death induced by either tertiary butyl hydroperoxide or tumor necrosis factor alpha. After tertiary butyl hydroperoxide treatment, total reactive oxygen species production was increased more than 3-fold compared with cells that did not express core and cytochrome P450 2E1. Mitochondrial depolarization and reduced glutathione depletion occurred as well, and cell death was prevented by inhibition of mitochondrial permeability transition or caspase activity. Confocal microscopy showed that the mitochondria themselves were the origin of the reactive oxygen species. In the absence of core/cytochrome P450 2E1 expression, mitochondrial changes and cell death did not occur. Ethanol treatment further decreased mitochondrial reduced glutathione content and exacerbated mitochondrial reactive oxygen species production, depolarization, and cell death. All these effects were prevented by the antioxidant N -acetylcysteine. CONCLUSIONS: Mitochondrial reactive oxygen species production is induced by hepatitis C virus core and cytochrome P450 2E1, resulting in a reduction of mitochondrial antioxidant capacity and sensitivity to oxidants and tumor necrosis factor alpha. Alcohol further depletes mitochondrial reduced glutathione, which exacerbates depolarization and cell death. Sensitization of mitochondria to oxidative insults is thus a potential mechanism for alcohol-related exacerbation of liver injury in chronic hepatitis C.

Alcohols↗
PubMed2005

Mitochondrial dysfunction in hepatitis C.

Chronic hepatitis C induces a state of hepatic oxidative stress that is more pronounced than that present in many other inflammatory liver diseases. This review summarizes recent information that the hepatitis C virus (HCV) core protein plays an important role in this phenomenon. Core protein localizes to mitochondria, particularly at the points of contact between mitochondrial outer membrane and endoplasmic reticulum. Its expression causes inhibition of electron transport at complex I, increased complex I reactive oxygen species (ROS) production, decreased mitochondrial glutathione, and increased mitochondrial permeability transition in response to exogenous oxidants and tumor necrosis factor-alpha. Possible mechanisms of the core protein effects include direct interaction with electron carriers and indirect effects mediated by changes in mitochondrial calcium. These results suggest that antioxidant approaches may prove beneficial for patients with chronic hepatitis C.

Hepacivirus↗
PubMed2005

A lipidomic study of the effects of N-methyl-N'-nitro-N-nitrosoguanidine on sphingomyelin metabolism.

Systems biology is a new and rapidly developing research area in which, by quantitatively describing the interaction among all the individual components of a cell, a systems-level understanding of a biological response can be achieved. Therefore, it requires high-throughput measurement technologies for biological molecules, such as genomic and proteomic approaches for DNA/RNA and protein, respectively. Recently, a new concept, lipidomics, which utilizes the mass spectrometry (MS) method for lipid analysis, has been proposed. Using this lipidomic approach, the effects of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) on sphingomyelin metabolism, a major class of sphingolipids, were evaluated. Sphingomyelin molecules were extracted from cells and analyzed by matrix-assisted laser desorption ionization-time of flight MS. It was found that MNNG induced profound changes in sphingomyelin metabolism, including the appearance of some new sphingomyelin species and the disappearance of some others, and the concentrations of several sphingomyelin species also changed. This was accompanied by the redistribution of acid sphingomyelinase (ASM), a key player in sphingomyelin metabolism. On the other hand, imipramine, an inhibitor of ASM, caused the accumulation of sphingomyelin. It also prevented some of the effects of MNNG, as well as the redistribution of ASM. Taken together, these data suggested that the lipidomic approach is highly effective for the systematic analysis of cellular lipids metabolism.

Amnion↗
PubMed2005

Novel approaches to using PDE4 inhibitors for antihypertensive therapy.

Phosphodiesterase (PDE)4 inhibitors are effective vasodilators. In addition to the treatment of asthma and other inflammatory diseases, such as chronic obstructive pulmonary disease, wide-spectrum PDE4 inhibitors may also be developed for use in antihypertensive therapy, especially in patients with impaired renal function and elevated pulmonary arterial pressure. Rational approaches to overcoming the intrinsic emetogenic response associated with PDE4 inhibition are discussed, and a dual-action drug development that incorporates L-type Ca2+ channel antagonism and selective PDE4 inhibition is proposed. The potential for research and development of such a dual-action agent should eventually provide healthcare professionals with a new category of therapeutic options with which to attempt to combat hypertension.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2005

[Transfection of HL-60 cells with CYP3A5 gene induces drug-resistant phenotype].

OBJECTIVE: To investigate if CYP3A5 gene is involved in the molecular mechanisms for multiple drug resistance in leukemia cells. METHODS: A full length cDNA of CYP3A5 gene was cloned, and a recombinant eukaryotic expression plasmid was constructed, then stably transfected cell lines were established. Furthermore, the sensitivity of those cell lines to several anticancer drugs were assessed by MTT and FCM assay. RESULTS: The recombinant plasmid was designated as pcDNA3-CYP3A5. Transfecting HL-60 cells (which didn't show transcript of CYP3A5 gene) with recombinant plasmid pcDNA3-CYP3A5 generated HL-60/CYP3A5 cell line, and transfecting of HL-60 cells with the parental pcDNA3 vector served as control HL-60/pc cell line. Daunorubicin induced remarkable apoptosis peaks in HL-60 and HL-60/pc cells, while such effect did not occur in HL-60/CYP3A5 cells (apoptosis cell percentage were 7.3%, 6.3% and 1.2%, respectively). Compared with HL-60 and HL-60/pc cells, HL-60/CYP3A5 cells were statistically significantly resistant to daunorubicin, aclacinomycin A, vincristine and harringtonine (resistance multiples were 2.89, 2.01, 4.05 and 2.79 times, respectively, P < 0.05), however the sensitivity to teniposide didn't change (resistance multiple was 1.04 times). CONCLUSION: Transcription of CYP3A5 gene in leukemia cells directly induces resistance to anthracyclines and alkaloids, however the cells are still sensitive to epipodophyllotoxins. Therefore, our findings confirmed a new mechanism of multidrug resistance.

Aclarubicin↗