Biomedical subjects

Wei Li

Publications and source records attributed to Wei Li.

At least 307 records · Page 17Linked to original sources

PubMed2005

Pigs in sequence space: a 0.66X coverage pig genome survey based on shotgun sequencing.

BACKGROUND: Comparative whole genome analysis of Mammalia can benefit from the addition of more species. The pig is an obvious choice due to its economic and medical importance as well as its evolutionary position in the artiodactyls. RESULTS: We have generated approximately 3.84 million shotgun sequences (0.66X coverage) from the pig genome. The data are hereby released (NCBI Trace repository with center name "SDJVP", and project name "Sino-Danish Pig Genome Project") together with an initial evolutionary analysis. The non-repetitive fraction of the sequences was aligned to the UCSC human-mouse alignment and the resulting three-species alignments were annotated using the human genome annotation. Ultra-conserved elements and miRNAs were identified. The results show that for each of these types of orthologous data, pig is much closer to human than mouse is. Purifying selection has been more efficient in pig compared to human, but not as efficient as in mouse, and pig seems to have an isochore structure most similar to the structure in human. CONCLUSION: The addition of the pig to the set of species sequenced at low coverage adds to the understanding of selective pressures that have acted on the human genome by bisecting the evolutionary branch between human and mouse with the mouse branch being approximately 3 times as long as the human branch. Additionally, the joint alignment of the shot-gun sequences to the human-mouse alignment offers the investigator a rapid way to defining specific regions for analysis and resequencing.

Animals↗

PubMed2005

Effects of rhubarb on isolated gastric muscle strips of guinea pigs.

AIM: To study the effects of rhubarb (dried root of Rheum officinale Baill.) on contractile activity of isolated gastric muscle strips of guinea pigs and its possible mechanism. METHODS: A total of 48 guinea pigs were killed to remove the whole stomach. Then, the stomach was opened and the mucosal layer was removed. Parallel to the circular fibers, muscle strips were cut from the body. Each isolated gastric muscle strip was suspended in a tissue chamber containing 5 mL Krebs solution, constantly warmed by water jacket at 37 degrees and bubbled continuously with a mixed gas of 950 mL/L O2 and 50 mL/L CO2. After being incubated for 1 h with 1 g tension, rhubarb of varied concentrations (1%, 2%, 7%, 20% and 70%) was added cumulatively into the tissue chamber at intervals of 2 min. Atropine (10(-6) mol/L) or isoptin (5 x 10(-8) mol/L) or hexamethonium (10(-5) mol/L) was given 2 min before the administration of rhubarb. The isometrical response was measured with an ink-writing recorder. RESULTS: Rhubarb dose dependently increased the resting tension of gastric body circular muscle (CM) (r = 0.726, P<0.05). Atropine (r = 0.829, P<0.05), isoptin (r = 0.764, P<0.05) and hexamethonium (r = 0.797, P<0.05) did not affect its action in a dose-related manner. Atropine apparently reduced the increasing action of 1%, 3%, 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Isoptin inhibited the effect of 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Hexamethonium reduced the increasing action of 1%, 10%, 30% and 100% rhubarb on the resting tension of gastric body CM. Rhubarb increased the contractile frequency of CM of body. While atropine, isoptin and hexamethonium did not inhibit the contractile frequency of gastric body CM in comparison with rhubarb at the same concentration, rhubarb at the highest concentration (100%) decreased the mean contractile amplitude of gastric body CM. Atropine, isoptin and hexamethonium did not affect the mean contractile amplitude of gastric body CM compared to rhubarb at the same concentration. CONCLUSION: Rhubarb has exciting actions on isolated gastric smooth muscle strips of guinea pig. The exciting action of rhubarb is partly mediated via cholinergic M receptor, cholinergic N receptor and L-type calcium channel.

Animals↗

PubMed2005

Transcriptional basis for exercise limitation in male eNOS-knockout mice with age: heart failure and the fetal phenotype.

Endothelium-derived nitric oxide (NO) is pivotal in regulating mitochondrial O(2) consumption (Vo(2)) and glucose uptake in mice. The aim of this study was to investigate the mechanism of age- and genotype-related exercise limitation in male endothelial NO synthase (eNOS)-knockout (KO, n = 16) and wild-type (WT, n = 19) mice. Treadmill testing was performed at 12, 14, 16, 18, and 21 mo of age. Vo(2), CO(2) production, respiratory exchange ratio, and maximal running distance were determined during treadmill running. There were good linear correlations for increase of speed with increase of Vo(2). The difference between KO and WT mice was not significant at 12 mo but was significant at 18 mo. Linear regression showed that KO mice consumed more O(2) at the same absolute and relative workloads, suggesting that Vo(2) was not inhibited by NO in KO mice. KO mice performed 30-50% less work than WT mice at each age (work = vertical distance x weight). In contrast to WT mice, the work performed by KO mice significantly decreased from 17 +/- 1.4 m.kg at 12 mo to 9.4 +/- 1.7 m.kg at 21 mo. Running distance was significantly decreased from 334 +/- 27 m at 12 mo to 178 +/- 38 m at 21 mo, and maximal Vo(2), CO(2) production, and respiratory exchange ratio per work unit were significantly higher in KO than in WT mice. Gene arrays showed evidence of a fetal phenotype in KO mice at 21 mo. In conclusion, age- and genotype-related exercise limitations in maximal work performed and maximal running distance in male eNOS-KO mice indicated that fetal phenotype and age were related to onset of heart failure.

Aging↗

PubMed2005

Profiles of PrKX expression in developmental mouse embryo and human tissues.

Protein kinase X (PrKX), karyotypically located on the human X chromosome, is a type I cAMP-dependent protein kinase. Although a specific role for PrKX has not yet been defined, PrKX gene expression in mouse and human tissues has been profiled only by in situ hybridization and Northern blot analyses and not by protein expression. To determine more precisely the PrKX protein levels, we developed specific anti-PrKX antibodies and examined gestationally staged mouse embryo sections by immunohistochemistry. These results showed that PrKX is ubiquitously distributed and highly expressed in murine central nervous system and heart tissues in early developmental stages and in most organs at later stages but was not detected in either connective tissues or bone. Using Western blots to detect PrKX, total protein extracts from eight different adult or fetal human tissues including brain, heart, kidney, liver, lung, pancreas, spleen, and thymus were analyzed. Although PrKX protein was present in each of the tissues tested, the protein levels varied depending on tissue type and developmental stage. Very low protein levels were found in heart tissues from a 5-month-old fetus and from an adult, whereas PrKX proteins were more abundant in fetal brain, kidney, and liver tissues compared with adult samples of the same tissue type.

Animals↗

PubMed2005

Thymidine phosphorylase gene transfer inhibits vascular smooth muscle cell proliferation by upregulating heme oxygenase-1 and p27KIP1.

OBJECTIVE: Thymidine phosphorylase (TP) reportedly promotes endothelial cell migration and induces heme oxygenase (HO)-1 expression. However, its effect on vascular smooth muscle cells (VSMCs) is poorly understood. In this study, we examined the effect of TP on VSMCs in vitro and in vivo. METHODS AND RESULTS: Phagemid vector encoding human TP gene was transfected into rat VSMCs, and a clone overexpressing TP was selected (C2). C2 showed a slower migration and proliferation than VSMCs cloned with empty vector (pC) under basal, serum-stimulated, and hypoxic conditions. This decrease in proliferation correlated with TP-induced HO-1 expression and was reversed by inhibitors of either TP or HO activity. Furthermore, in C2, the cyclin-dependent kinase inhibitor (p27KIP1) was much more abundant than in pC, and the cell cycle was arrested at the G1 phase. TP or HO activity inhibitors decreased p27(KIP1) expression in C2 to the level seen in pC. Adventitial TP gene delivery significantly reduced neointimal VSMC migration and neointima formation in balloon-injured rat carotid arteries. CONCLUSIONS: TP overexpression upregulated HO-1 expression and consequently increased p27(KIP1) in cultured VSMCs, and inhibited VSMC migration and proliferation in vitro and in vivo. TP represents a promising target for treating vascular obstructive disease.

Angioplasty, Balloon↗

PubMed2005

Enhanced solar irradiance across the atmosphere-sea ice interface: a quantitative numerical study.

A radiative transfer model for the coupled atmosphere-sea ice system is used to study the change in downward irradiance across the air-ice interface. Computations demonstrate that the downward solar irradiance can be significantly enhanced across the air-ice interface. The enhancement is mainly due to light in the ice that is scattered upward and then totally reflected by the air-ice interface. It depends primarily on the change in the index of refraction across this interface and the optical properties of the sea ice, but also on the direct solar and sky illumination of the interface.

Journal Article↗

PubMed2005

[Therapeutic effects of combination of arsenic trioxide with low-dose all-trans retinoic acid on induction of remission acute promyeloeytic leukemia].

OBJECTIVE: To observe the therapeutic efficacy and side effects of arsenic trioxide (As2O3)combined with low-dose all-trans retinoic acid (ATRA) on remission induction in newly-diagnosed and relapsed patients with acute promyeloeytic leukemia (APL). METHODS: 224 patients of APL, 156 newly diagnosed patients, aged 34 (13 approximately 62), with a male/female ratio of 1.56, and 28 relapsed patients, aged, aged 34 (12 approximately 63), with a male/female ratio of 1.89, underwent As2O3 + ATRA therapy. The therapeutic effects was compared with that of As2O3 alone treatment on 40 newly diagnosed patients and 25 relapsed patients and that of ATRA alone treatment on 36 newly diagnosed patients and 15 relapsed patients. The treatment protocol for the combination group was as following: As2O3 was administered intravenously at a dose of 10 mg/day and ATRA was given orally three times per day at a dose of 10 mg. The complete remission (CR) rate, period to CR, incidence of early death and side effects were observed in the three groups. RESULTS: In the newly-diagnosed patients, there was no significant difference in CR rate among the three groups (92.5% for the As2O3/LD-ATRA group, 83.8% for the ATRA group, and 90% for the As2O3 group respectively). In comparison with As2O3 alone, administration of LD-ATRA to the patients in the As2O3/LD-ATRA group significantly shortened the period to CR (the medium time to CR was 28 days for the As2O3/LD-ATRA group and 39 days for the As2O3 group respectively). As compared to ATRA alone, treatment with As2O3 with low-dose ATRA showed a significantly lower incidence of early death (2.5% for the As2O3/LD-ATRA group and 13.9% for the ATRA group respectively). In the relapsed patients, the CR rate was significantly higher in the group treated with As2O3/LD-ATRA (71.4% for the As2O3/LD-ATRA group, 32.0% for the ATRA group, and 43.0% for the As2O3 group respectively). The combined use of LD-ATRA with As2O3 did not further enhance toxic side effects as compared to As2O3 alone or ATRA alone. CONCLUSION: As2O3/LD-ATRA regimen is superior to either regimen given alone to patients with APL. It is an efficient therapeutic approach to APL patients using a combination of As2O3 with low-dose ATRA.

Adolescent↗

PubMed2005

Laterality of brain areas associated with arithmetic calculations revealed by functional magnetic resonance imaging.

BACKGROUND: Asymmetry of bilateral cerebral function, i.e. laterality, is an important phenomenon in many brain actions: arithmetic calculation may be one of these phenomena. In this study, first, laterality of brain areas associated with arithmetic calculations was revealed by functional magnetic resonance imaging (fMRI). Second, the relationship among laterality, handedness, and types of arithmetic task was assessed. Third, we postulate possible reasons for laterality. METHODS: Using a block-designed experiment, twenty-five right-handed and seven left-handed healthy volunteers carried out simple calculations, complex calculations and proximity judgments. T1WI and GRE-EPI fMRI were performed with a GE 1.5T whole body MRI scanner. Statistical parametric mapping (SPM99) was used to process data and localize functional areas. Numbers of activated voxels were recorded to calculate laterality index for evaluating the laterality of functional brain areas. RESULTS: For both groups, the activation of functional areas in the frontal lobe showed a tendency towards the nonpredominant hand side, but the functional areas in the inferior parietal lobule had left laterality. During simple and complex calculations, the laterality indices of the prefrontal cortex and premotor area were higher in the right-handed group than that in the left-handed group, whereas the laterality of the inferior parietal lobule had no such significant difference. In both groups, when the difficulty of the task increased, the laterality of the prefrontal cortex, premotor area, and inferior parietal lobule decreased, but the laterality of posterior part of the inferior frontal gyrus increased. CONCLUSIONS: The laterality of the functional brain areas associated with arithmetic calculations can be detected with fMRI. The laterality of the functional areas was related to handedness and task difficulty.

Brain↗

PubMed2005

Functional properties of PDIA from Aspergillus niger in renaturation of proteins.

Functional properties of protein disulfide isomerase A (PDIA) from Aspergillus niger were investigated using ribonuclease A, glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and prochymosin as substrates. PDIA was shown to function as an isomerase catalyzing the refolding of denatured and reduced ribonuclease A. PDIA also exhibited trx-independent chaperone activity preventing the aggregation of reduced, denatured GAPDH, an enzyme lacking disulfide bonds. Both isomerase activity and chaperone function of PDIA were essential for the efficient refolding of the reduced, denatured prochymosin.

Aspergillus niger↗

PubMed2005

Proanthocyanidin from grape seeds potentiates anti-tumor activity of doxorubicin via immunomodulatory mechanism.

The purpose of this study was to investigate the anti-tumor activities of proanthocyanidin (PA) from grape seeds and doxorubicin (DOX) in vitro as well as in vivo, either alone or in combination and to explore the immunomodulatory mechanism in tumor-bearing mice. PA (12.5 approximately 200 mg/l) or DOX (0.01 approximately 1 mg/l) for 24 h significantly inhibited YAC-1 cell proliferation (IC(50) 57.53 or 0.198 mg/l, respectively) in a concentration-dependent manner using microculture tetrazolium (MTT) assay. Meanwhile, a combination of PA (12.5, 25 mg/l) with DOX strongly inhibited cell proliferation with IC(50) values of DOX decreasing by 0.09 and 0.045 mg/l, respectively. In mouse tumor xenograft models, intraperitoneal administrations of PA (10 mg/kg) daily or DOX (2 mg/kg) every other day for 9 days significantly inhibited the growth of sarcoma 180, whereas a combination of the two strongly inhibited tumor growth as compared with PA or DOX alone (p<0.01). In contrast to PA treatment, DOX inhibited Con A-stimulated lymphocyte proliferation, IL-2 and IFN-gamma productions, NK cell cytotoxicity and CD4+/CD8+ ratio, while the administration of PA combined with DOX significantly enhanced the above immune responses as compared with the tumor-bearing control (p<0.01). Taken together, these results suggest that PA has anti-tumor activity and increases the anti-tumor activity of DOX, and the mechanism might be related partially to immunopotentiating activities through the enhancements of lymphocyte proliferation, NK cell cytotoxicity, CD4+/CD8+ ratio, IL-2 and IFN-gamma productions.

Animals↗

PubMed2005

[Clinical study on primary repair for bile duct injury during laparoscopic cholecystectomy].

OBJECTIVE: To evaluate the place of primary repair of bile duct injury during laparoscopic cholecystectomy (LC). METHODS: Between 1994 and 2004, 53 of a total 14 302 cases were identified with bile duct injury. The indication, methods and outcome of primary repair for 17 cases of bile duct injury were analyzed. RESULTS: Forty-Two of 53 cases of bile duct injury were identified at the time of operation, thirty three involved a tear of the common, hepatic or right hepatic bile duct, and 17 cases received primary repair. Drainage tubes were placed in 7 cases, and biliary drainage through the cystic duct was performed in 10 cases. All patients recovered well and got out of bed within 6 hours postoperatively. The alimentary tract recovered in 24 hours after operation in all cases, and their mean hospitalization was 4.6 days. Sixteen patients were followed up, and no stricture of bile duct was found. CONCLUSION: Repair of bile duct injury during LC is safe and effective in selected cases.

Adult↗

PubMed2005

A novel linkage to generalized vitiligo on 4q13-q21 identified in a genomewide linkage analysis of Chinese families.

Generalized vitiligo is a common, autoimmune, familial-clustering depigmentary disorder of the skin and hair that results from selective destruction of melanocytes. Generalized vitiligo is likely a heterogeneous disease, with five susceptibility loci reported so far--on chromosomes 1p31, 6p21, 7q, 8p, and 17p13--in white populations. To investigate vitiligo susceptibility loci in the Chinese population, we performed a genomewide linkage analysis in 57 multiplex Chinese families, each with at least two affected siblings, and we identified interesting linkage evidence on 1p36, 4q13-q21, 6p21-p22, 6q24-q25, 14q12-q13, and 22q12. Subsequently, to extract more linkage information, we investigated our initial genomewide linkage findings in a follow-up analysis of 49 new families and additional markers. Our initial genomewide linkage analysis and our subsequent follow-up analysis have identified a novel linkage to vitiligo on 4q13-q21, with highly significant linkage evidence (a nonparametic LOD score of 4.62 [P=.000003] and a heterogeneity LOD score of 4.01, under a recessive inheritance model), suggesting that 4q13-q21 likely harbors a major susceptibility locus for vitiligo in the Chinese population. We observed a minimal overlap between the linkage results of our current genomewide analysis in the Chinese population and the results of previous analyses in white populations, and we thus hypothesize that, as a polygenic disorder, vitiligo may be associated with great genetic heterogeneity and a substantial difference in its genetic basis between ethnic populations.

China↗

PubMed2005

DFT/TDDFT studies of the geometry, electronic structure and spectra of (12S)-1,4,7,10-tetraazadicyclo[10,3,0]-pentadecane-3,11-dione and its derivatives.

The FT-Raman and UV-visible spectra of (12S)-1,4,7,10-tetraazadicyclo[10,3,0]-pentadecane-3,11-dione and its derivatives were obtained and discussed. The harmonic vibrational wavenumbers and the corresponding Raman scattering activities in their electronic ground-states were calculated at the DFT-B3LYP/6-31G(d) level of theory. The calculated wavenumbers were then scaled and compared with the experimental values. The 7-(2,4-dinitrophenyl)-(12S)-1,4,7,10-tetrazadicyclo[10,3,0]-pentadecane-3,11-dione derivative has mainly an amide (II) character, while the others have an amide (I) character. Moreover, the different substituents do not cause a significant shift of the vibrational mode of the macrocyclic plane. The electronic vertical excitation energy and the oscillator strength were determined with the help of TDDFT calculations and by employing pure (BLYP) and hybrid (B3LYP, B3P86, and mPW1PW91) functionals together with the 6-31G(d) basis set. The BLYP functional reproduces the UV-vis absorption spectra better than the B3LYP, B3P86, or mPW1PW91 hybrid functionals. A dimolecular model, which considers hydrogen-bonded structures, proved that strong inter- and intramolecular hydrogen bonds are present in these compounds. Due to the transannular effect, the UV-vis absorption spectrum of macrocyclic dioxotetraamines is completely different from that of single amide compounds.

Bridged Bicyclo Compounds, Heterocyclic↗

PubMed2005

The histone octamer influences the wrapping direction of DNA on it: Brownian dynamics simulation of the nucleosome chirality.

In eukaryote nucleosome, DNA wraps around a histone octamer in a left-handed way. We study the process of chirality formation of nucleosome with Brownian dynamics simulation. We model the histone octamer with a quantitatively adjustable chirality: left-handed, right-handed or non-chiral, and simulate the dynamical wrapping process of a DNA molecule on it. We find that the chirality of a nucleosome formed is strongly dependent on that of the histone octamer, and different chiralities of the histone octamer induce its different rotation directions in the wrapping process of DNA. In addition, a very weak chirality of the histone octamer is quite enough for sustaining the correct chirality of the nucleosome formed. We also show that the chirality of a nucleosome may be broken at elevated temperature.

Animals↗

PubMed2005

[Laparoscopic treatment of esophageal hiatal hernia: analysis of 11 cases].

OBJECTIVE: To investigate the effect and safety of laparoscopic treatment in patients with esophageal hiatal hernia. METHODS: Eleven patients with esophageal hiatal hernia, 9 males and 2 females, with the mean age of 56, accepted laparoscopic treatment. Two cases were treated by hernia repair merely and 9 cases were treated by hernia repair and fundoplication (Nissen's operation) one of which accepted laparoscopic cholecystoectomy at the same time. RESULTS: All patients were treated successfully. The operation time was 2.5 hours (1.5 - 5 hours) and the blood loss was between 20 - 200 ml. The patients began to accept liquid diet 24 - 36 hours after operation. There was no postoperative complication and all the clinic symptoms disappeared. The mean hospitalization time was 8 days (6 - 15d). CONCLUSION: Laparoscopic treatment of esophageal hiatal hernia provides a safe and minimal invasive procedure.

Adult↗

PubMed2005

Behavioural study of the D-galactose induced aging model in C57BL/6J mice.

Rodent chronically injected with D-galactose (D-gal) has been used as an animal aging model for brain aging or anti-aging pharmacology research. However, the dosage of D-gal used to establish this model in mice has been reported in a wide range. To study the dose-dependent effect of D-gal on rodent behaviour, we investigated the learning and memory ability of C57BL/6J (C57) mice after 8-week subcutaneous injection of D-gal at different doses by Morris water maze (MWM) and object recognition test (ORT). In addition, locomotor activity test (LAT) was also performed to examine the neuromuscular function. In comparison of vehicle (0.9% saline)-treated mice, D-gal-treated mice at dose of high (200 mg/kg per day) and middle (100 mg/kg per day) doses showed significant longer latency to platform and less target quadrant search time and distance in MWM In ORT, D-gal at high and middle doses reduced the discrimination index (DI) of mice more significantly than low dose (50 mg/kg per day), although all three doses of D-gal reduced the DI of mice significantly. Furthermore, D-gal at high and middle doses significantly decreased locomotor activity of the mice in LAT. Throughout three tests, D-gal induced behavioural impairments in C57 mice at high and middle doses tended to be in the same degree. These results indicate that d-gal can induce the behavioural impairment of C57 mice in a dose-dependent manner from 50 to 100 mg/kg, higher dose than 100 mg/kg cannot further deteriorate its behavioural performance.

Aging↗

PubMed2005

Novel CACNA1S mutation causes autosomal dominant hypokalemic periodic paralysis in a Chinese family.

Hypokalemic periodic paralysis (HypoPP) is an autosomal dominant disorder which is characterized by periodic attacks of muscle weakness associated with a decrease in the serum potassium level. The skeletal muscle calcium channel alpha-subunit gene CACNA1S is a major disease-causing gene for HypoPP, however, only three specific HypoPP-causing mutations, Arg528His, Arg1,239His and Arg1,239Gly, have been identified in CACNA1S to date. In this study, we studied a four-generation Chinese family with HypoPP with 43 living members and 19 affected individuals. Linkage analysis showed that the causative mutation in the family is linked to the CACNA1S gene with a LOD score of 6.7. DNA sequence analysis revealed a heterozygous C to G transition at nucleotide 1,582, resulting in a novel 1,582C-->G (Arg528Gly) mutation. The Arg528Gly mutation co-segregated with all affected individuals in the family, and was not present in 200 matched normal controls. The penetrance of the Arg528Gly mutation was complete in male mutation carriers, however, a reduced penetrance of 83% (10/12) was observed in female carriers. No differences were detected for age-at-onset and severity of the disease (frequency of symptomatic attacks per year) between male and female patients. Oral intake of KCl is effective in blocking the symptomatic attacks. This study identifies a novel Arg528Gly mutation in the CACNA1S gene that causes HypoPP in a Chinese family, expands the spectrum of mutations causing HypoPP, and demonstrates a gender difference in the penetrance of the disease.

Adolescent↗

PubMed2005

Nigramides A-S, dimeric amide alkaloids from the roots of Piper nigrum.

[structure: see text] Fifteen novel dimeric amide alkaloids possessing a cyclohexene ring, nigramides A-O (1-15), as well as four novel dimeric amide alkaloids possessing a cyclobutane ring, nigramides P-S (17-20), have been isolated from the roots of Piper nigrum. Their structures were elucidated on the basis of their spectroscopic data. The biosynthestic hypothesis of nigramides A-O (1-15) was proposed by an intermolecular Diels-Alder reaction from the corresponding monomeric amides. On the basis of this biosynthetic hypothesis, the first study of the thermal and Lewis acid mediated Diels-Alder reactions of piperine in different organic solvents and under solventless conditions is also described.

Alkaloids↗