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Biomedical subjects

P Z Wang

Publications and source records attributed to P Z Wang.

At least 19 recordsLinked to original sources
PubMed1999

[The Value of CT Scanning in the Diagnosis of Temporomandibular Joint Dysfunction]

OBJECTIVE:To evaluate the role of CT in the diagnosis of temporomandibular joint dysfunction MATERIAL: 48 temporomandibular joints of 26 patients suspecting osseous changes were examined by CT, with 1mm of layer thickness. All patients had Sch llers position projection as comparison. RESULTS:CT is more sensitive to detect the osseous changes of TMJ than Sch llers position projection, but not well demonstrating sclerosis of TMJ. The Sch llers position projection can only shows the lesion of lateral 1/3 of condyle, but CT including total condyle. CONCLUSION: CT is an important and sensitive tool in detecting osseous changes of temporomandibular joint.

Journal Article↗
PubMed1999

[Clinical Application of CT assisted Double Contrast Arthrography of Temporomandibular Joint]

OBJECTIVE:To introduce double-contrast arthrography of TMJ with reformatted sagittal and coronal CT imaging and to evaluate the value of its application in the diagnosis of temporomandibular joint dysfunction. METHODS: 14 patients in whom diagnosis can not be established with conventional arthrography were examined by double contrast arthrography with reformatted sagittal and coronal CT imaging. RESULTS: In double-contrast arthrography with CT imaging, 1 case was normal;1 case had anterior displacement with reduction;2 cases were anterior displacement without reduction, and 8 cases were with disk adhesion. CONCLUSION:The double contrast arthrography with reformatted sagittal and coronal CT imaging was a very important alternative to conventional arthrography, and has special value to demonstrate adhesion of TMJ.

Journal Article↗
PubMed1999

[A Comparative Study of MRI and CT Double-Contrast Arthrography in Diagnosis of Disc Adhesion of TMJ]

OBJECTIVE:To compare the results of CT-assisted double-contrast arthrography and MRI in the diagnosis of adhesion of TMJ. MATERIAL:18 patients with adhesion of TMJ were examined by CT-assisted double-contrast arthrography and MRI, and their results were analysed including position, degree and with or without osseous changes. RESULTS:18 cases of adhesion were demonstrated on CT-assisted double-contrast arthrography, and that only 6 cases of them were diagnosed on MRI.CONCLUSION: CT-assisted double-contrast arthrography is more sensitive and accurate than MRI in demonstrating the disk adhesion of TMJ.

Journal Article↗
PubMed1999

[CT findings in the recurrent oral maxillofacial tumors eroding the central skull base]

OBJECTIVE:To domonstrate the CT manifestations of the recurrent oral maxillofacial tumors invading the middle skull base.METHODS:CT detections with axial (37 cases) and coronal (26 cases) scans were performed in thirty-seven patients who suffered from the recurrent oral maxillofacial tumors.All lesions were proven histopathologically.RESULTS:Four patterns of the central skull base erosion showing on CT images were encompassed:1.resorption of the outer cortical margin (5 cases);2.resorption of both outer and inner cortical laminae (24 cases);3.enlargement of the ovale foramen (3 cases);4.combined of sclerosis and resorption of the skull base (5 cases).The sphenoid greater wing involvement by the recurrent lesions was more frequently seen in our series (36 cases).Twenty four patients with the recurrent lesions were identified as following intracranial structures affected:the cavernous sinus (n=16),temporal lobe (n=15),and pituetary (n=1).CONCLUSION:It is believed that involvement of the intracranial structures is in close relationship with the aforementioned erosive patterns of the central skull base.The role of CT examination for evaluating the oral maxillofacial recurrent lesions invading the central skull base is very important.

Journal Article↗
PubMed1997

[Evaluation of 28 cases of salivary malignancies with MR imaging]

Twenty-eight cases of MRI of the salivary malignancies confirmed histopathologically were shown in this paper.By observing separately and comparatively with SE (spin echo) T2 weighted imaging and PE(field echo) imaging,the authors consider that (1)the malignant tumors within the salivary glands displaying low and intermediate signal intensities on T2 weighted image may be thought as a characteristic sign in the diagnostic processes. (2) PE imaging as an effective method is able to differentiate the tumors from the calcification and fibrosis which were low and intermediate signal intensities on T2 weighted image. (3)the locations and sizes of the tumors have directly influenced on their marginal manifestations and adjacent normal tissue structures.

Journal Article↗
PubMed1995

Radiographic findings in Langerhans' cell disease affecting the mandible.

The radiographic features of histopathologically diagnosed mandibular Langerhans' cell disease are described for 29 cases of the condition. We divided the patients into two groups: adults (age 27 to 60 years) and juveniles (age 1.5 to 15 years). A characteristic sign in juveniles was an osteolytic lesion with an uneven margin and either a continuous or discontinuous periosteal reaction. Because of the wide variability in radiographic presentation in adults, it was very difficult to differentiate this from other lesions in adults on the basis of radiologic criteria.

Adolescent↗
PubMed1995

[Analysis of treatment in 84 cases of severe pancreatitis].

84 patients who suffered from severe pancreatitis were treated in our hospital. In order to compare the efficacy of different therapy in early, middle and recent stages, the patients were divided into 3 groups. In early stage group (Jan, 1983-Dec, 1985) the treatment mainly was surgical drainage of the pancreas, the mortality was 72.7%. In middle stage group (Jan, 1986-Jan, 1989) the main treatment consisted of incision and decompression of pancreatic capsule, debridement of pancreas and inhibiting pancreatic secretion, the mortality decreased to 34.8%. In recent stage group (Jan, 1990-Jan, 1994) the therapy was Integrated Chinese Traditional and Western Medicine which comprised the method used in middle stage with TCM including acupuncture depending upon the syndrome. The mortality further lowered to 25.6%.

Adolescent↗
PubMed1994

Replication-specific conversion of the Staphylococcus aureus pT181 initiator protein from an active homodimer to an inactive heterodimer.

The Staphylococcus aureus rolling circle plasmid pT181 regulates its replication by controlling the synthesis of its initiator protein RepC. RepC is inactivated during pT181 replication by the addition of an oligodeoxynucleotide, giving rise to a new form, RepC*. We analyzed RepC and RepC* in four classes of mutants: plasmid copy number mutants, two classes of RepC mutants affecting different portions of the protein and oriC (origin) mutants. We have found that in the cell with wild-type RepC there are similar relative amounts of RepC and RepC*, regardless of copy number, and that the conversion of RepC to RepC* is replication dependent. Genetic and biochemical evidence is presented that RepC functions as a dimer and that during replication the RepC homodimer is converted to the RepC/RepC* heterodimer.

Bacterial Proteins↗
PubMed1993

Origin recognition specificity in pT181 plasmids is determined by a functionally asymmetric palindromic DNA element.

The leading strand replication origin of pT181 plasmids consists of two adjacent inverted repeat elements (IR-II and IR-III), which are involved in origin recognition by the initiator (Rep) protein. The conserved core element, IR-II, which contains the initiation nick site, is induced by Rep to form a cruciform structure, probably the primary substrate for the initiation of rolling circle replication. The divergent repeat, IR-III, constitutes the determinant of origin recognition specificity. We show here that the distal arm of IR-III is not required for sequence-specific recognition, whereas the proximal arm and central region are required. Since the initiator is dimeric, we presume that it binds symmetrically to IR-III. A unique type of DNA-protein interaction is proposed, in which the lack of sequence requirement for the distal arm is a consequence of binding to the adjacent IR-II, which thereby polarizes the stringency of binding to the two arms of IR-III. In addition, genetic evidence indicates that both the spacing and the phasing of IR-II to IR-III are crucial for function and that the central segment of IR-III may serve to position the two flanking half-sites for optimal interaction of Rep with IR-III.

Amino Acid Sequence↗
PubMed1993

Measurement of gene expression by translational coupling: effect of copy mutations on pT181 initiator synthesis.

We have prepared and analyzed two types of gene fusion between the replication initiator gene, repC, and the reporter gene, blaZ, in order to investigate the relationship between pT181 plasmid copy number and RepC initiator protein production. A series of pT181 copy mutant plasmids, with copy numbers ranging from 70 to 800 copies per cell, were analyzed. In one type of gene fusion used in this study, blaZ was translationally coupled to the C-terminal end of the repC coding sequence such that native forms of both proteins were produced. This gene fusion arrangement, which permitted monitoring of RepC production (as BlaZ activity) by plasmids using the protein for their own replication, demonstrated a linear relationship, with one exception, between RepC production and plasmid copy number over a 20-fold range. In the second type of fusion, blaZ was translationally fused to the C-terminal end of repC. As the translational fusion did not produce active RepC protein, the fusion-containing pT181 derivatives were maintained in a strain which provided RepC in trans, and were thus analyzed at constant copy number. In contrast to previous analyses of this type, our translational fusion constructs expressed repC at levels proportional to the copy numbers of the plasmids from which the fusions were prepared. Using these data, we have calculated a minimum figure for the number of RepC molecules synthesized per replication event.

Amino Acid Sequence↗
PubMed1993

Trends in physician-diagnosed asthma prevalence in Manitoba between 1980 and 1990.

We attempted to assess recent changes in the prevalence of physician-diagnosed asthma and the possible influence of diagnostic exchange on these trends. The routinely collected data of the provincial Health Insurance Plan (physicians' claims) were used to determine the annual prevalence of physician-diagnosed asthma in Manitoba. Results indicate that the prevalence of physician-diagnosed asthma increased for all age groups in both male and female subjects between 1980 and 1990. The average increases were the highest in the age group 5 to 14 years for both sexes. The average increases varied with age and there were significant differences between the two sexes. There was evidence of increasing diagnostic exchange, that is, a tendency to label patients with asthma instead of alternative diagnoses. This was particularly prominent in those younger than 35 years of age. However, the increased prevalence of physician-diagnosed asthma, even for the younger population, cannot be fully explained by diagnostic exchange.

Adolescent↗
PubMed1993

[Radiologic similarity and dissimilarity of Histiocytosis X in the mandible between non adult and adult]

28 cases of Histiocytosis X in the mandible were divided into two groups:the non adult group (19 cases,21 foci).and the adult group(9 cases,12 foci).their similarity and dissimilarity in radiological appearances were contrasted individually.The authors consider there were different roentgenographic manifestations between the two groups according to the diversity of physilological and morphological configuration in the mandible.The former group which had its characteristic roentgenologic feature displayed a radiolucent region with an irregular margin mostly accompanied with a periosteal reaction at the inferior and lateral surfaces of the mandible.Owing to lacking above mentioned demonstration,it was difficult to distinguish the lesions of later group from other disease in the mandible.

Journal Article↗
PubMed1993

[The pathological changes of lip biopsies and dental caries on Sjogren's syndrome]

This paper showed that in 110 cases of Sjogren's syndrome(SS),the caries incidence was high and was related to the salivary gland lesions.In comparison with 90 matched no SS group,the incidence of caries in SS was 88.18%,and in no SS group 73.33%(P<0.01).The average of caries in cases with more than ten inflammatory foci were significantly increased than in those less than ten,no significant difference in the average of caries was observed between primary and secondary SS.The amounts of salivary excretion measured were significantly decreased in 30 cases with SS than in no SS group cases,and the more the inflammatory foci,the less the salivary excretion.

Journal Article↗
PubMed1992

Specificity of origin recognition by replication initiator protein in plasmids of the pT181 family is determined by a six amino acid residue element.

We have investigated the specificity of replication origin recognition by the initiator proteins of a set of six closely related Staphylococcus aureus plasmids, the pT181 family. These plasmids replicate by an asymmetric rolling-circle mechanism using plasmid-coded initiators that nick the replication origins and form a phosphotyrosine bond at the 5' nick terminus. Five of the plasmids are in different incompatibility groups and their initiator proteins do not cross-complement the cloned origins of any but their own plasmid. One pair is weakly incompatible and their initiator proteins and origins do cross-complement for replication in vivo. This pattern of cross-reactivity led to the prediction that the determinant of specificity would correspond to a homologously positioned set of six residues in the C-terminal domain of the protein, some 80 residues away from the active site tyrosine, that are divergent for all of the compatible plasmids and identical for the incompatible pair. Site-directed mutagenesis was used to exchange these six residues among three pairs of plasmids and these exchanges brought about the predicted switching of origin recognition specificity. Single substitution within this six residue set reduced or eliminated the activity of the protein but did not alter the origin recognition specificity. These six and flanking residues cannot form an amphipathic alpha-helix nor do they conform to the classical helix-turn-helix or other known DNA binding motifs. A novel type of interaction is suggested in which the protein binds to its recognition site, bends and melts the DNA, and causes or enhances the extrusion of an adjacent cruciform containing the nick site. This configuration would juxtapose the nicking target and the active site tyrosine residue and would unwind the highly G + C-rich replication origin.

Amino Acid Sequence↗
PubMed1992

A radiologic study of pulmonary metastases originating from oral and maxillofacial tumors.

A retrospective clinical and radiologic study was carried out on 103 consecutive cases of oral and maxillofacial malignant conditions in which pulmonary metastasis occurred. The most frequent primary site was the palate. The neoplasm most commonly involved was the adenoid cystic carcinoma. Pulmonary metastases were classified into five types: solitary, multiple nodular, multiple "massy," diffuse, and miliary.

Adolescent↗