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Biomedical subjects

X Ma

Publications and source records attributed to X Ma.

At least 235 records · Page 13Linked to original sources
PubMed1998

[An experimental study on the regenerating ability of the condylar cartilage of the rabbit].

OBJECTIVE: To investigate the regenerating ability of the condylar cartilage of the adult rabbit. METHODS: A fullthickness defect was created in the condylar cartilage of the adult rabbit, with or without penetrating into the subchondral bone. RESULTS: In the cases of the condylar cartilage defect without penetration into the subchondral bone, the defects were repaired with fibrous tissue partly. However, in those the defect penetrated the subchondral bone, the defects were repaired with cartilage-like tissue at four and eight weeks periods, then the regenerated tissue transformed into the bone-like tissue. CONCLUSION: The defect of the condylar cartilage can't be repaired with cartilage, and the reparative cells were the undifferentiated mesenchymal cells originated from the bone marrow.

Animals↗
PubMed1998

[A macroscopic and microscopic study of the relationship between the superior lateral pterygoid muscle and the disc of the temporomandibular joint].

OBJECTIVE: To find out the relationship between the superior lateral pterygoid muscle (SLP) and the disc of the temporomandibular joint. METHODS: The cadavers consisted of 47 TMJ specimens from old humans, were used for the macroscopic and microscopic study. RESULTS: (1) The SLP may insert to the disc, the capsule, the anterior discal attachment of TMJ and to the condyle; (2) On average, 52% of the SLP fibres insert to the condyle, 10% to the articular disc, 24% to the capsule and 14% to the anterior attachment of the disc; (3) There is no association between displacement of disc and the proportion of the SLP insert to the disc; (4) The SLP fibres are jointed into the disc fibres by node or tendon, or jointed and to end. CONCLUSION: The majority of the SLP inserts to the condyle and the contraction of the little part of the SLP, which insert to the disc, should not result in the anterior displacement of the disc.

Female↗
PubMed1998

[Three dimensional finite element analysis on the mandibular complete overdenture supported by nature roots or implants].

OBJECTIVE: To investigate the stress distribution around the bone tissue of overdenture supported by teeth roots or implants in the process of mastication which may assist to improve the design of the dentures. METHODS: By means of CT scan, CAD and a three distribution finite element methods to study the stress distribution of the supporting tissue of overdenture supported by roots or implants when various attachment retentive apparatus and various bite forces were applied. RESULTS: No matter overdenture supported by roots or implants the stress distribution on bone tissue are difference between the bar and stud attachments, However these difference were minor compared with the difference caused by the direction of force. The stress value of cortical bone around the roots or implants with twenty degree oblique force is 2.2-3 times higher than that with vertical force. Overdenture supported by implants produced 2.5-4 times higher stress in the cortical bone around than that of overdenture supported by roots when various superstructures or various loads were applied. CONCLUSION: It must consider to reduce the stress peaks and provent bone resorption by increasing the number of implants and using the force-breaking design of implant super-strcture when the overdenture were supported with implants only.

Dental Implants↗
PubMed1998

[Ultrastructure of the synovial membrane and the articular cartilage in the temporomandibular joint of the rabbits with occlusal trauma].

OBJECTIVE: To study the effect of occlusal trauma on the ultra structure of rabbits' temporomandibular joints (TMJ) synovial membrane and articular cartilage. METHODS: TMJs from six rabbits with occlusal trauma and three control rabbits were studied by transmission electron microscopy. RESULTS: Degenerative changes of TMJ tissues were found. The articular surface of the condyle was damaged, and the chondrocytes showed signs of degeneration. The synovial lining cell consisted of a number of vimentin intermediate filaments (IFs) which were especially prevalent in the processes as well as paranuclearly. Microvilli on the cell membrane were commonly seen. The vermiform body in the deeper interstitium was also found. Our finding of punctate adherens between synoviocytes was firstly reported in the study. CONCLUSION: The occlusal trauma is really a factor inducing degenerative changes of the TMJ.

Animals↗
PubMed1998

[Detection of small alveolar bone lesions by digital subtraction radiography].

OBJECTIVE: To employ digital subtraction radiography (DSR) system developed by our school and co-ordinative unit, for diagnosis of small artificial alveolar bone lesions, in order to evaluate the system. METHODS: Seventy-two 0.2-0.9 mm3 lesions were produced in premolar and molar areas of the dry human mandibles. The reference and subsequent radiographs were taken before and after lesions being made. The small lesions were detected by conventional radiographs and by DSR method respectively. RESULTS: As for 0.2-0.5 mm3 lesions, the detections by both DSR and conventional methods were less than 50%. As for 0.7 mm3 lesions, the detection by DSR and conventional methods were 57.5% and 38.7%, respectively (P < 0.01). As for 0.9 mm3 lesions, the accuracy of the detection by DSR and conventional methods was 89.3% and 57.3% (P < 0.01). CONCLUSION: The detectability of small alveolar bone lesions by DSR system was obviously superior to the conventional method.

Alveolar Process↗
PubMed1998

[Vascular structure of malignant tumours of the mandible shown by specimen arteriography].

OBJECTIVE: To investigate the vascular structure of different kinds of malignant tumours of the mandible. METHODS: Specimen arteriography was performed on 11 cases of malignant tumours of the mandible. RESULTS: Malignant tumours could be divided into two groups: 1. the hypervascular tumours, the arteries are dilated, distributed evenly and arranged in a bush-like pattern. 2. hypovascular tumours, the scanty arteries are distributed unevenly without dilation, in some areas, the shape of arteries are irregular and arranged in a network pattern. CONCLUSION: Variation in vascular structure of malignant tumours in the mandible may be related to the outcome of regional chemotherapy.

Adolescent↗
PubMed1998

[Management of severe Budd-Chiari syndrome by spleen-internal jugular venous shunt].

OBJECTIVE: To study the operative method for severe Budd-Chiari syndrome. METHOD: 17 patients with severe Budd-Chiari syndrome were treated with splenectomy and spleen-internal jugular venous shunt. RESULT: Follow up for 3 to 20 months 11 patients showed excellent results, 5 good results and 1 died. CONCLUSION: Spleen-internal jugular shunt is effective for the patients with severe Budd-Chiari syndrome.

Adult↗
PubMed1998

[Thrombolysis by staphylokinase in rabbits with experimental pulmonary embolus].

Thrombolysis effect of recombinant staphylokinase (rSaK) developed in China was evaluated in rabbits with experimental pulmonary embolus model. 125I-labeled human fibrin blood clot was prepared in vitro and was injected through jugular vein resulting in a pulmonary embolus. Twenty thousands AU.kg-1(rSaK-H) or 5000 AU.kg-1(rSaK-L) of rSaK was infused in 0.5 h at constant rate by a peristaltic 20,000 U.kg-1. Another 20,000 AU.kg-1 of rSaK was infused within 2.5 h(rSaK-2.5 h). The residual labeled blood clot in lungs were found to be 62% +/- 11% (rSaK-H), 78% +/- 7% (rSaK-L), 92% +/- 7% (NS), 60% +/- 13% (SK), and 64% +/- 16% (rSaK-2.5 h). 125I-labeled degradation products in blood and urine were also statistically higher in thrombolytic agents treated group than those in NS controls. The results suggest that the thrombolytic effect of rSaK was determined by total dose and not determined by infusion time. Two of seven rabbits in the rSaK 2.5 h infusion group, the bleeding time was prolonged to more than 10 minutes while no prolongation was seen in rSaK high dose group. The clot lysis curves were very similar in 0.5 h or 2.5 h treatment of rSAK in vitro. Michaelis-Menten kinetics studies in vitro revealed that the Kms of rSaK and SK were almost the same, while a higher maximal velocity(34 kBq.min-1) was observed in rSaK than that in SK (10 kBq.min-1).

Animals↗
PubMed1998

[Evaluation of the effect of causes of death of advanced schistosomiasis patients on the life span of population by using potential years of life lost analysis].

AIM: To evaluate the effect of the causes of death of advanced schistosomiasis patients on the life span of population in an area where schistosomiasis had been under control by applying the indicators of potential years of life lost (PYLL) and rate of PYLL (PYLLR). METHODS: Using the formula of calculation of PYLL and PYLLR, the causes of death of 487 patients of advanced schistosomiasis in 3 previously endemic townships of Shanghai suburb. RESULTS: Of 487 cases who died between 1955 and 1995, the PYLLR of all causes of death was 256.3@1000. The main causes of death were hepatic failure (100.3@1000), liver carcinoma (43.4@1000) and cancer of other organs (24.8@1000). In the 1960s, the PYLLR of advanced schistosomiasis complicated with hepatic failure and upper digestive tract hemorrhage was 222.2@1000 and 34.5@1000, the PYLLR of the complications of schistosomal liver cirrhosis, hepatic failure and hemorrhage accounted for 67.5% of the total PYLLR, being apparently higher in the non-splenectomy group than in the splenctomty group. After the schistosomiasis was under control, both PYLL and PYLLR decreased linearly. As compared with the 1960s, the PYLLR of all causes of death and the causes of death of the complications of schistosomal liver cirrhosis in the 1990s has declined by 62.9% and 83.2%, respectively, the PYLLR of upper digestive tract hemorrhage was found only 0.3@1000 in the last 5 years. CONCLUSION: PYLL and PYLLR analysis could be used to quantify the effect of complications of advanced schistosomiasis and other causes of death on the life span of population.

Adolescent↗
PubMed1998

[In vitro sensitivity of Plasmodium falciparum to chloroquine, piperaquine, pyronaridine and artesunate in Yuxi prefecture of Yunnan province].

AIM: To assess the sensitivity of Plasmodium falciparum to four antimalarials. METHODS: WHO standard in vitro microtest was used. RESULTS: The resistance rates of the malaria parasite to chloroquine, piperaquine pyronaridine and artesunate were 85.7%, 66.7%, 38.1% and 5.0%, respectively. CONCLUSION: Among the antimalarials tested in Yuxi Prefecture, Yunnan Province, high resistance of P. falciparum to chloroquine and piperaquine was found. The sensitivity of P. falciparum in part of the cases to pyronaridine decreased. However, most of the cases were relatively sensitive to artesunate.

Adolescent↗
PubMed1998

[Functional phage display of human interferon alpha lc/86D].

We have successfully displayed human interferon-alpha lc/86D(IFN-alpha lc/86D) on the surface of the filamentous bacteriophage using a phagemid vector system (pCANTAB5E). The IFN-alpha lc/86D cDNA was fused to a DNA sequence encoding the amino-terminal domain of pIII, a minor coat protein exposed at one end of the phage. Fusion gene was packaged into phagemid particles upon superinfection with M13K07 helper phage. Expression of IFN-alpha lc/86D was verified by its reactivity with IFN-alpha l specific neutralizing antibodies and the phage displayed IFN-alpha lc86D was found to possess antiviral biological activity on VSV challenged WISH cells comparable to that of human recombinant IFN-alpha lb. These results demonstrate that IFN-alpha lc/86D can be displayed on phage in a correctly folded and functionally active form, and this system can be applicable to the sorting of a large repertoire of phage-displayed IFN-alpha lc/86D variants.

Antiviral Agents↗
PubMed1998

[The three-dimensional analysis of mandibular overdenture supported by implants].

In recent decade, the treatment in which two or four implants are placed in an edentulous patient to support an overdenture has been more effective and safe, and the retention and stability of overdenture have been improved by the use of attachments fabricated on implant abutments. This study aimed to investigate the supporting tissue stress distributions of implant-overdenture with a 3-D finite element model built by CT scan and CAD technology when various attachments and loads were used respectively. The results demonstrated that the establishment of the three-dimensional finite element model with CT scan and CAD technique had saved time and effort, and it did not damage the experiment model. The tissue structure was quite distinct in imaging. In terms of the stress distribution of bone tissue in the overdenture supported by implant, there was a difference between bar attachment and stud attachment. However, such a difference was minor as compared with the difference caused by the bite force direction. The stress value of cortical bone around abutment with 20 degree oblique force was 2.2-3 times that with vertical force. Therefore, to reduce high stress peaks, attention must be paid to the direction of the bite force, as this variable is much more important than the design of superstructure.

Aged↗
PubMed1998

[Study of the physiological characteristics of a strain which can change the color of red lead on Dunhuang mural].

A strain which was isolated from Dunhuang Murual was investigated. It belongs to Flavobacterium. In media added in Pb3O4, colonies show brown and black. After identified pigments, it showed that the brown was caused by the oxidation of Pb3 O4 into PbO2 by the strain. The optimal oxidative condition is at pH 9.8, 37 degrees C and dark environment. The genes for oxidation is on plasmid and the oxidation was inhibited under pure O2 and N2 conditions, too 5 x 10(-3) mol/ml NaN3 is enough. The strain was able to absorb lead initiative. The transmission electron microscope showed that lead locate in protoplasts.

Color↗
PubMed1998

[Studies on microbiological factor in colour change of mogao graffito's mural. II. Effect of microorganism on the pigment of imitative mural].

Throung the assay and analysis of the imitative mural after cultivated with microorganisms, it has been shown that microorganisms had a pronounced effect on the pigments of the mural: the pigments secreted by microorganisms changed the colour of the mural, and produced much oxalic acid salt, which damaged the formation of crystals of the pigment, moreover, the chemical combination valence of Pb3O4 had been changed due to the metabolic products of microorganisms, that may play an important role in the chemical change of Pb3O4.

Bacterial Physiological Phenomena↗
PubMed1998

[Studies on microbial factor on color change of Dunhuang mural. I. Classification of microbes on color-changed mural and property of some typical species].

Microbial strains were isolated from 51 typical color changed samples of mural in 6 grottos of Dunhuang Mogao Gretto. After identification, it is proved that belong to 6 genera of bacteria and 5 genera of mould. Bacillus, Alcaligenes and Penicillium were dominant species in all of them. In the imitative experiment, it is found that Cladosporium sp., A. niger and two strains of bacteria have a great effect on the color change of red pigment of mural and aging of sizing agent.

Bacteria↗
PubMed1998

[Internalization and replication of Edwardsiella tarda in HEp-2 cells].

It is demonstrated that Edwardsiella tarda possesses the ability to invade cultured epithelial HEp-2 cells by both lysis-counting assay and thin-section electron microscopy. Among fifteen strains of E. tarda, 6 strains internalized into HEp-2 cells and located mainly in vesicles. After internalization, the bacteria replicated in the host cells and then released into medium. Pretreatment of the HEp-2 cells with various concentration of cytochalasin D (0.1-5.0 micrograms/ml) or cytochalasin B (2.5-10.0 micrograms/ml) significantly reduced the amount of internalized bacteria in a dose-dependent manner. While pretreatment of HEp-2 cells with 0.25-100 mumol/L colchicine did not show any effect on the invasiveness of E. tarda. This strongly indicates that microfilaments are required for the internalization of E. tarda into HEp-2 cells and that microtubules are not involved in the entrance of E. tarda into HEp-2 cells.

Cells, Cultured↗
PubMed1998

[Studies on microbial factor on color change of Dunhuang mural. III. Effect of Cladosporium sp. on color-change of red lead in the surface of mural].

The conditions isolated Cladosporium sp. from Mural of Dunhuang grottoe germinated on the surface of imitated mural were as follows: 20 degrees C RH 60% or 30 degrees C RH 50%, which could be reached occasionally in some grottoes. Bone glue had protective function on red lead, while Cladosporium sp. could decompose bone glue and form some metabolite (such as oxalic acid, etc) as it grows. Then it could form a special chemical circumstance, which promoted the change from red lead to while lead.

Cladosporium↗