Biomedical subjects

Yi Wu

Publications and source records attributed to Yi Wu.

At least 37 records · Page 2Linked to original sources

PubMed2005

Candidate multi-peptide-vaccine against classical swine fever virus induced potent immunity with serological marker.

Our previous study proposed a protective multi-peptide-vaccine (MPV) with Freund's adjuvant against classical swine fever virus (CSFV). In this study, another candidate MPV, using aluminum adjuvant, was further examined. All immunized pigs kept healthy during the experimental period, while the control group rapidly showed clinical symptoms and died. Moreover, anti-sera from MPV-immunized pigs could interact with peptides involved in the MPV, in contrast to anti-sera from non-immunized or infected ones. This property permits MPV-immunized pigs to be easily differentiated from infected ones with simple serological method. Therefore, this new MPV is suitable to act as a candidate marker vaccine against CSFV.

Adjuvants, Immunologic↗

PubMed2005

Microsurgical resection of tumors lateroventral and ventral to the high cervical spinal cord.

BACKGROUND: Since there are a complex anatomic structure and vital function in the high cervical spinal cord, it is difficult to remove the tumors lateroventral and ventral to the high cervical spinal cord. This clinical study was undertaken to analyze surgical approaches, manner of tumor resection and postoperative management. METHODS: Thirty-four patients underwent microsurgical excision of tumors lateroventral and ventral to the high cervical spinal cord by means of three approaches. The tumors comprised mostly Schwannoma and meningioma (88.24%, 30/34) in this group. Tumor volume varied from 3.0 cm x 2.5 cm x 2.0 cm to 12 cm x 3.0 cm x 2.5 cm. Of the 34 patients, 4 had dumbbell-shaped tumors growing outside the spinal canal and 7 tumors growing into the intracranium. RESULTS: The tumor was totally removed in 32 patients (94.1%). Follow-up for 7 months to 6.4 years (median 3.6 years) showed a recovery of a normal life or work ability in 30 (83.3%) patients. CONCLUSION: Modified operative approaches and microsurgical techniques can raise the rate of total tumor removal and reduce the disability of patients.

Adolescent↗

PubMed2005

A role for Mer tyrosine kinase in alphavbeta5 integrin-mediated phagocytosis of apoptotic cells.

Efficient phagocytosis of apoptotic cells is crucial for many cellular processes. One of earliest signals to the phagocyte is the expression of phosphatidylserine (PS) on the outer surface of the apoptotic cell that provides a potent 'eat-me' signal. Recognition of PS occurs either directly, via PS receptor (PS-R), or indirectly via alphavbeta5(3) integrin or Mer-family tyrosine kinases through the opsonizing proteins milk fat globule-EGF factor 8 protein (MFG-E8), or growth arrest specific factor-6 (Gas6), respectively. Because Mer and alphavbeta5 integrin share PS-dependent recognition signals, we investigated their post-receptor signaling cascades following receptor activation. Using a constitutively active form for Mer (CDMer) or Gas6 as a ligand to stimulate Mer, we found that Mer activation induced a post-receptor signaling cascade involving Src-mediated tyrosine phosphorylation of FAK on Tyr(861), the recruitment of FAK(Tyr861) to the alphavbeta5 integrin, and increased formation of p130(CAS)/CrkII/Dock180 complex to activate Rac1. Coexpression of Mer with alphavbeta5 integrin had a synergistic effect on Rac1 activation, lamellipodial formation and the phagocytosis of apoptotic cells. Interestingly, Gas6 or CDMer failed to stimulate p130(CAS) tyrosine phosphorylation or phagocytosis in beta5-deficient CS-1 cells or in mutant beta5DeltaC-expressing cells, suggesting that Mer is directionally and functionally linked to the integrin pathway. The present data indicate that receptors that recognize apoptotic cells in the context of PS functionally crosstalk to amplify intracellular signals to internalize apoptotic cells. Moreover, our data link another PS-dependent signal to the CrkII/Dock180/Rac1 module.

Animals↗

PubMed2005

Short communication: HIV type 1 phenotype, tropism, and sequence patterns: association and preference.

In this study, the relationship between biological phenotypes, coreceptor usages, and sequence patterns of V1V2 or V3 regions on HIV-1 envelope gp 120 was carefully analyzed based on the existing isolates in the Los Alamos National Laboratory sequence database. Obviously, SI/NSI phenotypes were closely linked to the capability of HIV-1 to use coreceptor CXCR4, but not CCR5. Moreover, compared to NSI or R5 isolates, SI or X4 HIV-1 isolates significantly prefer higher net charges and the loss of the N-linked glycosylation site in the V3 loop, but they show no preference in either net charge or N-linked glycosylation of the V1V2 region. In addition, no significant relationship between V1V2 length and virus tropism or phenotypes was observed.

Glycosylation↗

PubMed2005

[Clinical application of a modified posterior vaginal wall hammock in female pelvic floor reconstruction].

OBJECTIVE: To explore the feasibility and effectiveness of a modified posterior vaginal wall hammock (PVWH) in the treatment of female pelvic organ prolapse without removal of uterus. METHODS: Thirty-two patients with different defects of pelvic organ prolapse underwent a modified PVWH. The procedures included restoring the position of prolapsed uterus by suturing polypropylene mesh to bilateral sacro-spinous ligaments, strengthening utero-sacral ligament by intra-vaginal slingplasty (Tyco Healthcare Group), forming a new recto-vaginal fascia and strengthening levator ani muscle. RESULTS: The average operating time was 55 minutes and hemorrhage was 150 ml respectively. Recovery of uterine prolapse was achieved in all cases. After an average follow up of seven months, no vagina distortion, shortening and dyspareunia were observed. One patient had uterine cervix elongation three months after operation. The relieving rate of subjective symptoms was more than 50%. CONCLUSIONS: Female uterine prolapse could be cured by the modified PVWH and the uterus could be successfully reserved during pelvic floor reconstruction with promising short-term results. More clinical trials are needed to evaluate its effectiveness, safety and long-term outcome.

Adult↗

PubMed2005

[Intraoral curved osteotomy for malar reduction].

OBJECTIVE: To present a new method for reduction of the prominent malar complex by using the curved osteotomy through intraoral incision. METHODS: According to the anatomical characteristics of the malar complex, a new curved osteotomy was designed for reduction of the prominent malar complex. This method, that made malar arch move toward backside, inside and upside, lowered the whole malar complex and gain better contour of malar area. RESULTS: From 2001 to 2003, 41 patients were treated with the intraoral curved osteotomy [for reduction of the prominent malar complex. All patients obtained good results. CONCLUSIONS: Through the intraoral approach, the curved osteotomy method could lower the whole prominent malar complex and get better contour of malar area.Intraoral curved osteotomy for reduction of the prominent malar complex could be an ideal method with better face contour, simpler technique, and fewer complications.

Adult↗

PubMed2004

[Effects of standardized three-stage rehabilitation on recovery of neurological function in stroke patients with hemiplegia].

OBJECTIVE: To explore the effects of standardized three stages' rehabilitation on the neurological function in stroke patients with hemiplegia. METHODS: All 52 patients firstly are brought into two blocks: primary cerebral infarction and primary cerebral hemorrhage then are divided into treated group and controlled group randomly. Patients in the treated group are given Standardized Three Stages' Rehabilitation, while those in the controlled group are only given normal internal medicine treatments that are the same as the treated group but without Standardized Three Stages' Rehabilitation. All patients would be assessed with the scale of Clinical Neurological Function Defects (CNFD) at the entering time, the end of 1st month, 3rd month and 6th month respectively after stroke. RESULTS: The scores of the treated group are lower than those of the controlled group (P < 0.001) at every stage, the margins between every stage's scores in the treated group are greater than those in the controlled group (P < 0.001). The scores of the treated group's patients are about 51%, 34%, 18% and 8% of total scores at the entering time, the end of 1st month, 3rd month and 6th month after stroke differently, but that of the controlled group are about 58%, 54%, 42% and 37% of total scores differently. The margins between the scores of entering time and that of the end of 1st month, 3rd month and 6th month in the treated group are 17%, 33% and 43% of total scores respectively, but that of the controlled group are about 5%, 16% and 21% of total scores differently. CONCLUSION: Standardized three stages' rehabilitation could promote stroke patients' motor function of every stage obviously.

Adult↗

PubMed2004

[Whether VI region lymph nodes belong to primary site of the thyroid carcinoma or lateral cervical lymph node metastases].

OBJECTIVE: To discuss the evaluation of elective neck dissection (END) for the cN(0) patients with papillary thyroid carcinoma (PTC). METHODS: By analyzing the recurrent and metastatic region (thyroid, group VI lymph nodes, lateral neck region, beyond neck) of 139 PTC patients treated secondly in our hospital, group VI lymph nodal metastasis is divided into recurrence of primary site and distinguished from lateral neck lymph nodes. The clinical value of END for cN(0) PTC patients is also retrospectively analyzed. RESULTS: Thyroidal recurrence accounts for 83% (73/88). Level VI metastasis accounts for 76% (67/88), 17 patients have received END and account for 65% (17/26). Metastasis to lateral neck lymph nodes account for 17% (17/98), among these patients, 5 patients have received END and account for 19% (5/26). CONCLUSIONS: For the patients with cN(0) PTC, ipsilateral thyroid lobectomy plus level VI dissection is recommended and lateral END (level II-V) is not supported. For the patients with cN(0) but UB N(+) and/or CT N(+), lateral END (level II-V) is recommended. The necessity of CT examination in the diagnosis and treatment of thyroid cancer should be emphasized.

Adolescent↗

PubMed2004

Liquid chromatographic-tandem mass spectrometric method for the quantitation of huperzine A in dog plasma.

A rapid and sensitive LC-MS-MS method for the determination of huperzine A in dog plasma using huperzine B as internal standard has been developed and validated. The analyte and internal standard were extracted from plasma using n-hexane-dichloromethane-2-propanol (300:150:15, v/v/v), chromatographed on a C(18) column (5 microm, 50 mm x 4.6 mm i.d.) with a mobile phase consisting of acetonitrile-methanol-10mM ammonium acetate (35:40:25, v/v/v), and detected using a tandem mass spectrometer with a TurboIonSpray ionization interface. The run time was only 2 min. The assay was linear over the concentration range 0.05-20 ng/ml and intra- and inter-day precision over this range were <5.3% with good accuracy. The limit of detection in plasma was 0.01 ng/ml. The method was successfully applied to define plasma concentration-time curves of huperzine A in dogs after the last dose of an intramuscular injection (10 microg/kg per day for 15 days) of a sustained-release formulation of huperzine A.

Alkaloids↗

PubMed2004

A bridge from short-term to long-term left ventricular assist device--experimental verification of a physiological controller.

A physiological controller is a key component to optimize the performance of left ventricular assist devices (LVADs) from short term to long term (10-20 years). The difficulties of its design lie in the inaccurate modeling of any particular human cardiovascular system because of limited knowledge, the large fluctuation of systemic parameters in normal daily life, nonlinearity introduced by one-way heart valves, and restriction on available sensors. The desired physiological controller for a permanent LVAD is expected to handle different activity levels such as sleeping, resting and exercising, and different pathological levels of left ventricular failure. In this study, a physiological controller designed for a long-term continuous flow (CF) LVAD was tested in a mock circulatory loop. The pressure head across the LVAD and motor signals were used as feedback signals, which were obtained from long-term reliable sensors. Three activities and five different pathological levels of left ventricular failure were simulated to test the performance of the designed controller. The experimental results showed that the designed controller restored the total peripheral flow and arterial pressure, and decreased the left ventricular end-diastolic pressure to a safe range. The suction of the left ventricle was successfully reversed by the designed controller. The controller thus was proven to be able to control the LVAD properly in many of the possible physiological conditions experienced by LVAD recipients in long term.

Biomedical Engineering↗

PubMed2004

Studies on the effect of calcium in interactions between heparin and heparin cofactor II using surface plasmon resonance.

Heparin is the most acidic polysaccharide in the human body and as a result interacts with many cationic species, including ions and proteins, giving rise to myriad biologic activities. Heparin cofactor II (HCII) is a serine protease inhibitor that resembles antithrombin (ATIII) in its ability to be activated by heparin. The interaction of heparin with HCII has been the focus of many studies using affinity chromatography and fluorescence spectroscopy. In this study, surface plasmon resonance (SPR) spectroscopy was used to quantitatively measure the interaction of heparin and HCII using a heparin biochip prepared by covalently immobilizing preformed albumin-heparin conjugate. HCII contains multiple EF hand domains that represent putative calcium ion binding sites. The interactions of HCII with heparin, low-molecular-weight heparin, and heparin oligosaccharides (disaccharide, tetrasaccharide, hexasaccharide) were examined in solution competition experiments using SPR. The results also showed while calcium ions enhanced the heparin/HCII interaction, the activity of heparin-HCII complex against thrombin was not calcium dependent but can be enhanced by the presence of calcium.

Amino Acid Sequence↗

PubMed2004

[Genetic polymorphisms in X-ray repair cross-complementing gene 1 and susceptibility to papillary thyroid carcinoma].

OBJECTIVE: To study the association of polymorphisms in the X-ray repair cross-complementing gene 1 (XRCC1) and papillary thyroid carcinoma (PTC). METHODS: A hospital based, matched case-control study was carried out. The polymorphisms in XRCC1 for 105 pairs of cases with PTC and controls were identified by PCR-RFLP. RESULTS: The frequencies of Arg/Arg, Arg/Trp and Trp/Trp genotypes at XRCC1 Arg194Trp site were 47.6%, 49.5% and 2.9% among cases compared to 45.7%, 48.6% and 5.7% among controls. There was no statistically significant difference between the two groups (chi(2) = 1.07, P = 0.59). The frequencies of Arg/Arg, Arg/Gln and Gln/Gln genotypes at XRCC1 Arg399Gln site were 46.7%, 41.9% and 11.4% among cases, while 54.2%, 42.9% and 2.9% among controls respectively. There was statistically significant difference between the two groups (chi(2) = 6.40, P = 0.04). Individuals with Gln/Gln genotype had a 3.65-fold increased risk of developing PTC compared to Arg/Arg genotype (OR = 4.65, 95% CI: 1.24 - 17.45). The multivariate conditional logistic regression analysis showed that the XRCC1 Arg399Gln polymorphism, negative life events and X-irradiation history were associated with PTC, with odds ratios of 2.71 (95% CI: 1.22 - 6.05), 5.34 (95% CI: 1.40 - 20.38) and 0.38 (95% CI: 0.12 - 0.72) respectively. However, XRCC1 Arg194Trp polymorphism, drinking tea, fruit and economic levels did not show statistically significant associations with PTC. CONCLUSION: The Gln/Gln genotype at XRCC1 Arg399Gln site and negative life events significantly increased while X-irradiation history decreased the risk of developing PTC.

Adult↗

PubMed2004

[Expression and significance of alpha5beta1 integrin in abnormal scars].

OBJECTIVE: To study the expression of alpha5beta1 integrin in the abnormal scars and its role and significance in the formation and development of abnormal scars. METHODS: The expression of alpha5beta1 integrin was observed in hypertrophic scar (15 samples), keloid (15 samples) and normal skin (10 samples) with SP immunohistochemical method and colloidal gold immuno-electron microscopic technique. The data were semi-quantitatively analyzed. RESULTS: The expression levels of alpha5beta1 integrin in the fibroblasts of keloids and hypertrophic scars were higher than normal skin; the expression of alpha5beta1 integrin in the fibroblasts of keloids was higher than hypertrophic scars (P < 0.01). CONCLUSION: The alpha5beta1 integrin appears to have close relation to the formation and development of abnormal scars. To find a way to decrease the expression level of alpha5beta1 integrin in fibroblasts may be a new approach to inhibit scar hypertrophy.

Cicatrix↗

PubMed2004

[Single nucleotide polymorphisms and point mutations of ataxia telangiectasia mutated gene in Chinese of Han ethnicity].

OBJECTIVE: To explore the single nucleotide polymorphisms (SNPs) and point mutations of ataxia telangiectasia mutated (ATM) gene in Chinese of Han ethnicity. METHODS: The target fragments of the exon 39, exon 61 and exon 63 of ATM gene were first amplified using PCR technique, then screened for the SNPs and point mutations using single strand conformation polymorphism (SSCP) technique, finally the representative bands were sequenced for the verification of the new single nucleotide polymorphisms and point mutations using the automatic DNA sequencing technique. RESULTS: Six new SNPs were found in the exon 39, intron 61 and intron 63 of ATM gene. They are respectively the A/T polymorphisms at nucleotide 5689 and 5691 in exon 39, the T/G polymorphisms at nucleotide +69 and +99, the A/G polymorphism at nucleotide +94 in intron 61, the G/C polymorphism at nucleotide +17 in intron 63. Five new point mutations were found in the exon 61, intron 62 and exon 63 of ATM gene. They are respectively the T/G transversion at nucleotide 8618 in exon 61, the T/G transversion at nucleotide -13 in intron 62, the T/G transversion at nucleotide 8793, the G/A transitions at nucleotide 8816 and 8848 in exon 63. The known three SNPs, the G/A polymorphism at nucleotide 5557 in exon 39, the T/C polymorphism at nucleotide +104 in intron 61 and the T/C polymorphism at nucleotide -55 in intron 62, were verified in Chinese of Han ethnicity. CONCLUSION: There are great differences in the SNPs of ATM gene between Chinese of Han ethnicity and Caucasian.

Asian People↗

PubMed2003

Two-dimensional crystallization of rabbit C-reactive protein monomeric subunits.

C-reactive protein (CRP) is one of the most characteristic acute-phase proteins. Modified CRP is the monomeric form of native CRP and has recently been suggested to exist under physiological conditions. In the current work, CRP subunits were separated from stock CRP solution by size-exclusion chromatography. Two forms of two-dimensional crystals composed of monomeric CRP were obtained on negatively charged lipid monolayers: a previously reported form, MI, and a new form, MII. A projection map at 2.0 nm resolution of the two-dimensional MII crystals was obtained. The formation of the two forms of two-dimensional crystal exhibited a dependence on pH. At pH values of less than 5.5 the subunits assembled in MI packing, while at pH values greater than 6.5 they assembled in MII packing. When using modified CRP prepared by acidic denaturation, only MI crystals could be formed. The fact that CRP subunits produced by dissociation or denaturation could form highly ordered two-dimensional crystals indicates that they have a certain homogeneous structure, which supports the previous suggestion of the existence of modified CRP in vivo.

Animals↗

PubMed2003

Visualization of synaptotagmin I oligomers assembled onto lipid monolayers.

Neuronal exocytosis is mediated by Ca(2+)-triggered rearrangements between proteins and lipids that result in the opening and dilation of fusion pores. Synaptotagmin I (syt I) is a Ca(2+)-sensing protein proposed to regulate fusion pore dynamics via Ca(2+)-promoted binding of its cytoplasmic domain (C2A-C2B) to effector molecules, including anionic phospholipids and other copies of syt. Functional studies indicate that Ca(2+)-triggered oligomerization of syt is a critical step in excitation-secretion coupling; however, this activity has recently been called into question. Here, we show that Ca(2+) does not drive the oligomerization of C2A-C2B in solution. However, analysis of Ca(2+).C2A-C2B bound to lipid monolayers, using electron microscopy, revealed the formation of ring-like heptameric oligomers that are approximately 11 nm long and approximately 11 nm in diameter. In some cases, C2A-C2B also assembled into long filaments. Oligomerization, but not membrane binding, was disrupted by neutralization of two lysine residues (K326,327) within the C2B domain of syt. These data indicate that Ca(2+) first drives C2A-C2B.membrane interactions, resulting in conformational changes that trigger a subsequent C2B-mediated oligomerization step. Ca(2+)-mediated rearrangements between syt subunits may regulate the opening or dilation kinetics of fusion pores or may play a role in endocytosis after fusion.

Animals↗

PubMed2003

The status of the Japanese and East Asian bats of the genus Myotis (Vespertilionidae) based on mitochondrial sequences.

The genus Myotis includes the largest number of species in the family Vespertilionidae (Chiroptera), and its members are distributed throughout most of the world. To re-evaluate the phylogenetic position of East Asian Myotis species with respect to Myotis species worldwide, we analyzed mitochondrial gene sequences of NADH dehydrogenase subunit 1 and cytochrome b from 24 East Asian individuals as well as 42 vespertilionid bats determined previously. The results suggest that: (1) some individuals having the same species name in Europe and Japan do not form a monophyletic clade, indicating that some bat species exhibit morphological convergence, (2) Japanese Myotis mystacinus forms a sister relationship with Myotis brandtii (Palaearctic), and both species are included in the American clade implying that an ancestor of these species originated in North America, and (3) the Black whiskered bat, Myotis pruinosus, is endemic to Japan and forms sister relationships with Myotis yanbarensis and Myotis montivagus collected from Okinawa (Japan) and Selangor (Malaysia), respectively, implying that M. pruinosus originated from the south. The systematics of Japanese and East Asian Myotis bats were revisited by considering their phylogenetic relationships. Our study provides the first extensive phylogenetic hypothesis of the genus Myotis that includes East Asian and Japanese species.

Adaptation, Biological↗

PubMed2003

An advanced physiological controller design for a left ventricular assist device to prevent left ventricular collapse.

A continuous flow left ventricle assist device (LVAD), which is mainly composed of a continuous flow blood pump and a physiological controller, has only one control input, the rotational speed of the pump, but at least three performance criteria to meet. The challenge for the physiological controller of a long-term continuous flow LVAD is the adaptability to different cardiovascular loading situations and the ability to handle systemic and parametric uncertainties with only one control input. The physiological LVAD controller presented in this article exhibits good performance in terms of the three performance criteria in different physiological loading conditions, such as disturbance, resting, and moderate exercise, for a patient with congestive heart failure. The collapse of the left ventricle, which is an inherent problem for a continuous flow LVAD, has been prevented because of the control algorithm design.

Computer Simulation↗