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Biomedical subjects

W Qiu

Publications and source records attributed to W Qiu.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Diagnostic values of MRI in combination with DSA in vascular malformations of the head and neck].

OBJECTIVE: To evaluate prospectively diagnostic values of magnetic resonance imaging (MRI) as the initial examination for vascular malformations of the head and neck, and establish a flowchart based on radiodiagnostic features. METHODS: 45 patients with vascular malformations of the head and neck were evaluated prospectively with MRI. MRI was followed by angiography in 15 patients, contrast-enhanced CT in 15 patients. MRI was performed by using spin-echo pulse sequences with Philips Gyroscan NT 1.0 Teslaunit. RESULTS: In all cases, MRI demonstrated usefully, and there was no other single imaging modality that could provide information about internal structures and flow characteristics as much as MRI. It made differentiation between high-flow and low-flow lesions obvious, however MRI was inferior to angiography in delineation of feeder vessels. CONCLUSION: MRI can be used as the initial methods for diagnosis of vascular malformations in the head and neck, and could be combined with angiography in cases with high-flow or combined-flow lesions.

Adolescent↗
PubMed2000

[Effects of maxillary growth of Wistar rats with bilateral artificial cleft palate after premaxillary orthopedic treatment on expression of proliferating cell nuclear antigen(PCNA)].

OBJECTIVE: Being based on the principle of Latham's appliance, this experiment is designed to detect activity of osteoblasts in the maxillary sutures of Wistar rats with bilateral artificial cleft palate by immunohistochemistry technique, and evaluate the effects of this appliance on the growth and development of the maxilla. METHODS: The animal models of male infant Wistar rats with bilateral cleft palate were made by removing some palatal bones, splitting a "V" gap of 1.5 cm wide at the line between premaxilla and segments of maxilla. A sort of appliances, which could be fixed in the mouth of Wistar rats with bilateral cleft palate for correcting protrusion premaxilla was constructed basing on the principle of Latham's appliance. Then the diferent pathological changes of osteoblast proliferation between the experimental group and the two controlled groups were examined. The jugomaxillary sutrues, temporomalar sutures and sphenoipalatine suture were harvested 7, 14 days after premaxillar orthopedic treatment, followed by 4% paraformaldehyde fixing about 1 hour, demineralization with 15% EDTA and 0.5% paraformaldehyde for 48 hours, distilled water washing for a night, dimethylbenzene transparant dealing, and paraffin wax embeding. Proliferating Osteoblasts in all these sutures were investigated using immunohiostochemical technique with monoclonal antibodies of proliferating cell nuclear antigen (PCNA). RESULTS: Seven days after orthopedic treatment, no significant difference was observed between the experimental group and the two controlled groups. While after fourteen days, obvious PCNA-positive expression were observed in cells of all these sutures of the experimental group. CONCLUSION: The distribution of proliferating cells and the degree of cell proliferation change after premaxillary orthopedic treatment. And significant cell proliferation is observed in the experimental group, but there are no significant differences between the two controlled groups.

Animals↗
PubMed2000

[Clinical application of computed arthroscope of the temporomandibular joint].

OBJECTIVE: The effect of clinical application on the computed arthroscope of the temporomandibular joint (TMJ) is evaluated. METHODS: The single arthroscopic images were input into computer and memorized into magneto optical disk. With the help of Photoshop 5.0 in WINDOWS 95, the images were combined by technique of virtual process, adjusted by rotation of images, marginal blur, and chromatism correction to compound sagittal and/or coronal panoramic images of articular surfaces. According to different needs, the composite images can be printed with different printers. During the period from May 1998 to May 1999, the TMJ preoperative panoramic images were composed with computed arthroscope (CA) in the 32 joints. Of them, there were 12 joints with internal derangement (ID), 8 osteoarthrosis (OA), 8 adhesion, 2 disk perforation, and 2 synovial chondromatosis. The post-operative panoramic images were also made up to evaluate the surgical effects in 10 joints. RESULTS: In all of 32 joints, the 32 panoramic arthroscopic images of upper cavities were composed. In addition, the images of lower cavities were composed in 2 OA and 1 perforation. The postoperative panoramic images were also made up in 4 OA, 4 adhesion, and 2 synovial chondromatosis. All of the above-mentioned images showed integrally the entire structure of articular cavity, intracapsular pathologic/surgical appearances, and the relationships among the different tissues or articular surfaces. CONCLUSION: The CA can enhance the comprehensive ability of diagnostic arthroscope, and help to exchange and spread the experiences of the TMJ arthroscopic surgery.

Arthroscopy↗
PubMed2000

[Cephalometrical analysis of effects of premaxillary orthopedic treatment on maxillary growth of Wistar rats with bilateral artificial cleft palate].

OBJECTIVE: To measure the differences between the experimental group and the two controlled groups by using the cephalometric radiography technique to study the effects of premaxillary orthopedic treatments on the growth and development of maxilla. METHODS: To make an animal model with bilateral cleft palate by surgery operation: General anesthesia was carried on by injecting 2.5% pentobarbital (25 mg/kg) into abdominal cavity, then almost the same bone of rats' palate were removed from bilateral palate. An appliance, based on the principle of Latham's appliance was made and designed for premaxillary orthopedic treatment. It was fixed in rats' palate using pins under the condition of general anesthesia. After 20 days of orthopedic treatment, the rats were anesthetized by ether, and cephalometric films were taken under self-designed cephalometer and analysed aided by computer. RESULTS: The distances that represented the maxillary position in the posterior-anterior (PA) direction significantly increased (P < 0.05), while the angles that represented the direction of premaxillary growth significantly decreased (P < 0.05) between the experimental group and the two controlled groups. There were no significant difference between the two controlled groups. CONCLUSION: Premaxilla of rats can be effectively moved backward and rotated downward and backward on the PA direction by appliance. The appliance can move the segment palate forward during the premaxillary backword. The appliance can stimulate maxillary growth.

Animals↗
PubMed1999

Monoclonal antibodies that inhibit the transport function of the 190-kDa multidrug resistance protein, MRP. Localization of their epitopes to the nucleotide-binding domains of the protein.

Multidrug resistance in tumor cells is often accompanied by overexpression of multidrug resistance protein (MRP), a 190-kDa transmembrane protein that belongs to the ATP-binding cassette superfamily of transport proteins. MRP mediates ATP-dependent transport of a variety of conjugated organic anions and can also transport several unmodified xenobiotics in a glutathione-dependent manner. To facilitate structure-function studies of MRP, we have generated a panel of MRP-specific monoclonal antibodies (mAbs). Four of these mAbs, QCRL-2, -3, -4, and -6, bind intracellular conformation-dependent epitopes, and we have shown that they can inhibit the transport of several MRP substrates. Binding competition and immunoprecipitation assays indicated that mAbs QCRL-4 and -6 probably recognize the same detergent-sensitive epitope in MRP, whereas mAbs QCRL-2, -3, and -4 each bind distinct, non-overlapping epitopes. Fab fragments inhibit transport as effectively as the intact mAbs, suggesting that inhibition results from direct interactions of the mAbs with MRP. Immunodot blot and immunoprecipitation analyses revealed that the minimal regions of MRP sufficient for full reactivity of mAbs QCRL-2 and -3 are amino acids 617-858 and 617-932, respectively, which encompass the NH2-proximal nucleotide-binding domain (NBD). In contrast, the epitope bound by mAb QCRL-4 localized to amino acids 1294-1531, a region that contains the COOH-proximal NBD. However, none of the mAbs inhibited photolabeling of intact MRP with 8-azido-[alpha-32P]ATP. This suggests that rather than preventing nucleotide binding, the mAbs inhibit transport by interfering with substrate binding or by trapping MRP in a conformation that does not allow transport to occur. Our results also demonstrate for the first time that the NBDs of MRP can be expressed as soluble polypeptides that retain a native conformation.

ATP-Binding Cassette Transporters↗
PubMed1999

Two non-reactive ternary complexes of estrogenic 17beta-hydroxysteroid dehydrogenase: crystallization and preliminary structural analysis.

Human estrogenic 17beta-hydroxysteroid dehydrogenase (17beta-HSD1, EC1.1.1.62) is an important enzyme that catalyses the last step of active estrogen formation. 17Beta-HSD1 plays a key role in the proliferation of breast cancer cells. The three-dimensional structures of this enzyme and of the enzyme-estradiol complex have been solved (Zhu et al., 1993, J. Mol. Biol. 234:242; Ghosh et al., 1995, Structure 3:503; Azzi et al., 1996, Nature Struct. Biol. 3:665). The determination of the non-reactive ternary complex structure, which could mimic the transition state, constitutes a further critical step toward the rational design of inhibitors for this enzyme (Ghosh et al. 1995, Structure 3:503; Penning, 1996, Endocrine-Related Cancer, 3:41). To further study the transition state, two non-reactive ternary complexes, 17beta-HSD1-EM519-NADP+ and 17beta-HSD1-EM553-NADP+ were crystallized using combined methods of soaking and co-crystallization. Although they belong to the same C2 space group, they have different unit cells, with a = 155.59 A, b = 42.82 A, c = 121.15 A, beta = 128.5 degrees for 17beta-HSD1-EM519-NADP+, and a = 124.01 A, b = 45.16 A, c = 61.40 A, beta = 99.2 degrees for 17beta-HSD1-EM553-NADP+, respectively. Our preliminary results revealed that the inhibitors interact differently with the enzyme than do the natural substrates.

17-Hydroxysteroid Dehydrogenases↗
PubMed1999

Genetic diversity of ospC in a local population of Borrelia burgdorferi sensu stricto.

The outer surface protein, OspC, is highly variable in Borrelia burgdorferi sensu stricto, the agent of Lyme disease. We have shown that even within a single population OspC is highly variable. The variation of ospA and ospC in the 40 infected deer ticks collected from a single site on Shelter Island, New York, was determined using PCR-SSCP. There is very strong apparent linkage disequilibrium between ospA and ospC alleles, even though they are located on separate plasmids. Thirteen discernible SSCP mobility classes for ospC were identified and the DNA sequence for each was determined. These sequences, combined with 40 GenBank sequences, allow us to define 19 major ospC groups. Sequences within a major ospC group are, on average, <1% different from each other, while sequences between major ospC groups are, on average, approximately 20% different. The tick sample contains 11 major ospC groups, GenBank contains 16 groups, with 8 groups found in both samples. Thus, the ospC variation within a local population is almost as great as the variation of a similar-sized sample of the entire species. The Ewens-Watterson-Slatkin test of allele frequency showed significant deviation from the neutral expectation, indicating balancing selection for these major ospC groups. The variation represented by major ospC groups needs to be considered if the OspC protein is to be used as a serodiagnostic antigen or a vaccine.

Alleles↗
PubMed1999

Selection of quantitative criteria for evaluating metastases of a highly metastatic salivary adenoid cystic carcinoma cell line to the lungs of nude mice.

OBJECTIVE: To select reliable quantitative criteria for evaluating metastases of a highly metastatic salivary adenoid cystic carcinoma cell line (ACC-M) cell to the lungs of nude mice. MATERIALS AND METHODS: The within-group coefficients of correlation of 5 parameters were measured from lung slides using a video image digital analysis system (VIDAS), and the intergroup coefficients of correlation of 6 sets of parameters from all the lungs, which were taken from ACC-M lung metastases models, were calculated and statistically analyzed. RESULTS: The within-group coefficients of correlation of 5 parameters are as follows: ratio of area of metastases, t = 0.9 (P < 0.001); area of metastases, t = 0.7 (P < 0.05), size of lung section, numbers of metastases, and size of the largest metastatic focus all t < 0.4 (P > 0.05). The intergroup coefficients of correlation of the parameters are as follows: ratio of area of metastases was assigned 1, weight of the lung was 0.9755, and area of metastases was 0.8628. CONCLUSION: For evaluating lung metastases of ACC-M, the ratio of area of metastases and weight of the lung are precise; the area of metastases is also significant within the 6 quantitative parameters.

Animals↗
PubMed1999

[Long-term effectiveness of arthroscopic subsynovial sclerotherapy and suturing on recurrent dislocation of the temporomandibular joint].

OBJECTIVE: To evaluate long-term effect of arthroscopic surgery on recurrent mandibular dislocation. METHODS: 30 patients with 34 involved temporomandibular joints (TMJs) (26 unilateral, 4 bilateral) were treated by arthroscopic subsynovial sclerotherapy with or without a discal traction suture. Of them, four patients with 4 TMJs were undergone repeat arthroscopic operations. In total, 38 operations were performed in 34 TMJs. After arthroscopic lysis, lavage, and manipulation, the subsynovial sclerotherapy was performed with 5% sodium morrhuate and was located at retrodiscal lamina. Suturings were taken simultaneously in 19 cases, others (n = 19) were not sutured. The total amount of 5% sodium morrhuate was from 0.4 to 1.2 ml, and the numbers of injection points were from 2 to 5, and the subsynovial depth of injection was not more than 5 mm. The follow-up was from 1 mon to 8 years. RESULTS: The total success rate was 97% (33/34). There were 21 patients with 22 involved TMJs whose follow-ups were more than 2 years. The mean follow-up was 4 years (2-8 years). The long-term success rate was 95% (21/22). There were no serious complications. CONCLUSION: The long-term effectiveness of arthroscopic sclerotherapy and suturing on recurrent mandibular dislocation is stable.

Adult↗
PubMed1999

[Experimental study on the osteoradionerosis of jaw model of dogs with vascular corrosion casting].

OBJECTIVE: To study pathologic alterations of mandibular microvascular system in osteoradionecrosis of jaws (ORNJ) in order to disclose its pathologic mechanism. METHODS: The right maxillofacial regions of 10 dogs were exposed to cobalt-60 radiation with a total dose of 60-80 Gy and dental extraction were performed at 3, 6 months after radiation. The ORNJ was diagnosed by gross observation, X-ray film and histopathologic examination. Then, the vascular corrosion castings of jaws were implemented and investigated. RESULTS: At 12 months after radiation, 7 cases of ORNJ occured. It was discovered on the casting specimen that the continuity of inferior alveolar arteries remained intact except one case where the artery was obliterated due to lesion involvement. There were defects of vascular networks in the necrotic area with irregular capillaries proliferating in the periphery of lesions and around the inferior alveolar arteries, where x-ray examination showed new bone formation. CONCLUSION: Based on the experimental evidences, a new concept of pathogenesis of ORNJ is put forward: following the formation of "3-hypo" structures, local trauma-repairing process might induce capillary proliferation which bring about a large amount of mitotic death of endotheliocytes, the microcirculation failure takes place leading to ORNJ eventually.

Animals↗
PubMed1999

[Craniofacial resection for advanced malignant tumors in oral and maxillofacial region].

OBJECTIVE: To investigate the clinical significance of craniofacial resection for advanced malignant tumors of OMS region. METHODS: Forty-six patients underwent craniofacial resection for malignancies involving the anterior and middle cranial fossa over a 20-year period between June 1978 and December 1997 in our department were evaluated. The extents of cranial resections were anterior cranial fossa in 20 cases, middle crania fossa in 16 cases and anterior and middle skull base in 10 cases. There were 18 patients undergoing orbital exenteration simultaneously. 14 cases had limitted dura resected because of dural involvement. RESULTS: The survival rate at 3 and 5 years was 48.8% (20/41) and 35.1% (13/37), respectively. The survival rate at 10 years was 20.0% (4/20). CONCLUSION: Our results revealed a considerably fine prospect of craniofacial resection for patients with advanced malignancies in oral and maxillofacial region.

Adolescent↗
PubMed1999

[Diagnosis and treatment of internal jugular phlebectasia (three cases report].

OBJECTIVE: To discuss the diagnosis and treatment of patients with rare abnormal veins: the internal jugular phlebectasia. METHODS: Three patients with swollen during straining or crying were diagnosed as internal jugular vein dilatation by ultra-sonography, DSA and MRI. Then an operation of envelopment of the right internal jugular vein with the sternocleidomastoid muscle was performed in two cases. In the third case, the bilateral internal jugular ectasia, the right internal jugular vein were resected and the left internal jugular vein was enveloped with the resected vein. RESULTS: These three patients were treated satisfactorily by operation, and no recurrence in the following two years. CONCLUSION: To those who want their internal jugular phlebectasia to be treated, the operation of envelopment of internal jugular vein with sternocleidomastoid muscle is a good method.

Adolescent↗
PubMed1999

[Influence of radiotherapy on reconstruction flaps in oral and maxillofacial regions].

OBJECTIVE: To evaluate the influence of radiotherapy on reconstruction flaps in oral and maxillofacial regions and the radiation tolerance of flaps, and therefore provide clinical information for perioperative radiotherapy. METHODS: Sixty-six free flaps and 22 pedicled flaps were used in the reconstruction of oral and maxillofacial tumor defects. The success and healing of the total 88 reconstruction flaps(14 flaps in preoperative radiation group and 74 flaps in postoperative radiation group) were observed. The acute and late side effects of radiotherapy in the flaps of the postoperative group were studied as well. RESULTS: Of the preoperative 14 flaps, 12 were successful (85.7%), one partially successful and one failed. Of the postoperative 74 flaps, however, 73 were successful (98.6%) and only one partially successful. No total loss of the flap was noted in the postoperative group. The success and healing rates in the preoperative group were lower than those in the postoperative group significantly (P < 0.01-0.05). The rate of acute radiation response of flaps in the postoperative group was significantly lower than that in the surrounding normal tissues(35.1% versus 83.8%, P < 0.01). The late side effects of radiotherapy were rare. The radiation tolerance in different kinds of flaps was similar. CONCLUSION: Reconstruction flaps in oral and maxillofacial regions have a good radiation tolerance and routine postoperative radiation doses can be safely delivered.

Adult↗
PubMed1998

Inhibition of p130cas tyrosine phosphorylation by calyculin A.

P130cas is a dominant tyrosine phosphorylated protein in v-src-and v-crk-transformed cells. Tyrosine phosphorylation also occurs in response to integrin-mediated cell adhesion. P130cas has a unique structure with multiple SH2 and SH3 binding sites, which makes it a candidate docking protein that might be involved in several signal transduction pathways. Little is known about how p130cas itself is regulated. In this report we present evidence that tyrosine phosphorylated p130cas was rapidly dephosphorylated in several lymphatic cell lines after treatment with calyculin A, a serine/threonine phosphatase inhibitor. A similar result was obtained with okadaic acid, but higher concentrations and longer incubation times were required. Constitutive phosphorylation as well as receptor-cross linking-induced p130cas phosphorylation was inhibited. Furthermore, the p130cas-Crk association was disrupted by treatment of cells with calyculin A. However, the p130cas-Lyn association was not affected. These results suggest that calyculin A specifically affects SH2 domain-mediated protein-protein interactions and that Lyn does not bind to a susceptible SH2 domain. Furthermore, the data presented is consistent with the existence of a calyculin A-sensitive phosphatase or tyrosine kinase that may be a critical regulator of p130cas tyrosine phosphorylation.

Cell Aggregation↗
PubMed1998

Evoked potential estimation using modified time-sequenced adaptive filter.

A method called modified time-sequenced adaptive filtering (MTSAF) is applied to estimate evoked potential (EP) signals and track the temporal variations of EPs. The MTSAF consists of a set of adaptive filters (AFs), with each processing a time segment of EP data. After convergence, each AF reaches the best estimation of EP signals over its own time segment in terms of minimum mean squared error (MMSE). Numerical results of simulated and human EP data show that the MTSAF reaches better estimation of EPs than a conventional adaptive signal enhancer (ASE). With the MTSAF, the temporal variations of EPS across trials can be estimated to reveal more subtle variations of EPs, which may be of clinical value.

Algorithms↗
PubMed1998

[A prospective study on etiologic bacteria in 200 patients with pneumonia].

The etiologic agents in 200 patients with pneumonia were studied by the bacterial culture of sputums obtained from the protected single catheter brush or quantitative expectoration at one morning or three-morning expectoration. Two hundred patients were divided into 3 groups. Group 1 was Nosocomial pneumonia (NP patients). Group 2-1 and Group 2-2 were community acquired pneumonia (CAP patients). All cases in Group 1 and Group 2-2 suffered from significant underlying diseases while Group 2-1 did not. Gram-negative bacilli(GNB) were isolated from the specimens in Group 1 (87%) and Group 2-2 (75%), respectively. Pseudomonas (30.8%) and klebsiella (20.5%) were the predominant bacteria (in Group 1 and pseudomonas bacteria) in Group 1 and pseudomonas (27.3%), acinetobacter (23%) and kledsiella (18%) were the major etiologic agents in Group 2-2. The commonest pathogens in Group 2-1 were gram-positive cocci (75%), in which streptococcus (38%) and staphylococcus aureus (25%) were the dominant agents. Compared with Group 2, Group 1 suffered from more mixed bacteria and the agents presented severer drug-resistant. The prognosis was worse in Group 2-2 than in Group 2-1. The results showed that the GNB pneumonia was more common in the cases who had underlying disease, no matter whether the pneumonia was NP or CAP. These patients had more trouble on their antibiotic therapy. Thus it is important that doctors should use vigorous antibiotics timely while treating these patients' underying diseases.

Adult↗