Biomedical subjects

M Wang

Publications and source records attributed to M Wang.

At least 217 records · Page 12Linked to original sources

PubMed2001

[A biomechanical model of human knee-joint elastic articulate contact].

In this paper, based on the characterizations of human knee-joint anatomical structures and reports of the literature and experiments, a biomechanical model of the human knee-joint elastic articulate contact is developed under the conditions of sampling the human knee-joints. This model is believed to be a powerful tool for functional analysis of the knee, for evaluation of surgical and diagnostic procedures and for design of artificial joints.

Elasticity↗

PubMed2001

[Experiment of biodegradation of chlorobenzenes].

Four strains of microorganisms which were able to grow at the presence of 1,4-dichlorobenzene 1,2,4-trichlorobenzene and hexachlorobenzene were isolated from the sludge collected from two different sites after incubating about 2 months. During the growth of the mixed microorganisims on chlorobenzenes, the accumulating consumption of oxygen, the microbial population curve and the concentration of released Cl- were investigated. The result showed that the mixed microorganisms were able to utilize 1,4-dichlorobenzen and 1,2,4-trichlorobenzene as sole carbon source and energy source. The concentration of released Cl- may depend strongly on the activity of the living cells. The order in which the chlorobenzenes were readily degraded was 1,4-dichlorobenzenez[356.7 micrograms/(L.d)] > 1,2,4-trichlorobenzene[110.4 micrograms/(L.d)] > hexachlorobenzene[approximately 6 micrograms/(L.d)]. The number of the substituted chlorine on the chlorobenzenes directly resulted in the resistance to biodegradation.

Bacteria↗

PubMed2001

Posterior lumbar interbody cages do not augment segmental biomechanical stability.

The effect on stiffness of installing posterior threaded interbody cages at LA-L5 was evaluated using fresh human cadaveric spine specimens. The cages did not increase spine stiffness significantly in any tested range of motion. Supplemental posterior pedicular screw/rod instrumentation, however, significantly increased stiffness. The assertion that use of cages as isolated posterior implants improves stability may be invalid.

Aged↗

PubMed2001

Preliminary interspecific genetic maps of the populus genome constructed from RAPD markers.

We have constructed RAPD-based linkage maps for an interspecific cross between two species of the genus Populus (P. adenopoda and P. alba), based on a double pseudo-test-cross strategy. Of a total of 360 polymorphic fragments scored, 290 showed a test-cross configuration, corresponding to DNA polymorphisms heterozygous in one parent and null in the other. In the female parent, P. adenopoda, 82 markers were grouped in 19 different linkage groups (553 cM), whereas in the male parent P. alba, 197 markers established a much more complete framework map with an observed genome length of 2300 cM covering 87% of the total P. alba genome. The larger number of test-cross markers detected for the P. alba parent than for the P. adenopoda parent might be due to a higher level of heterozygosity in the former than in the latter. In this study, we detected only a small percentage (2%) of the intercross dominant markers heterozygous in both parents and segregating 3:1 in the progeny. The further focus in this mapping study should be on the identification of more intercross markers, to align the two parent-specific maps into a consensus map for mapping important genes causing species differentiation during long evolutionary divergences.

Chromosome Mapping↗

PubMed2001

Dominant negative guard cell K+ channel mutants reduce inward-rectifying K+ currents and light-induced stomatal opening in arabidopsis.

Inward-rectifying potassium (K+(in)) channels in guard cells have been suggested to provide a pathway for K+ uptake into guard cells during stomatal opening. To test the proposed role of guard cell K+(in) channels in light-induced stomatal opening, transgenic Arabidopsis plants were generated that expressed dominant negative point mutations in the K+(in) channel subunit KAT1. Patch-clamp analyses with transgenic guard cells from independent lines showed that K+(in) current magnitudes were reduced by approximately 75% compared with vector-transformed controls at -180 mV, which resulted in reduction in light-induced stomatal opening by 38% to 45% compared with vector-transformed controls. Analyses of intracellular K+ content using both sodium hexanitrocobaltate (III) and elemental x-ray microanalyses showed that light-induced K+ uptake was also significantly reduced in guard cells of K+(in) channel depressor lines. These findings support the model that K+(in) channels contribute to K+ uptake during light-induced stomatal opening. Furthermore, transpirational water loss from leaves was reduced in the K+(in) channel depressor lines. Comparisons of guard cell K+(in) current magnitudes among four different transgenic lines with different K+(in) current magnitudes show the range of activities of K+(in) channels required for guard cell K+ uptake during light-induced stomatal opening.

Arabidopsis↗

PubMed2001

[Research current status and prospect of the stress and remodeling adaptation models in living bone tissue].

The remodeling processes in living bone are the mechanisms by which bone tissue adapts its overall structure to changes in its mechanical load environment. In this paper, based on literature, the research current status of the stress and remodeling adaptation models in living bone tissue is reviewed and evaluated. Its future research direction and how to break the back of it are also prospected in the paper.

Animals↗

PubMed2001

[Magnetic stimulation: theory and advance].

Magnetic stimulation is a noninvasive diagnostic and therapeutic technique. The basic theory of magnetic stimulation is presented briefly. Its advances are elaborated in three aspects of mechanism, instrumentation and applications. The problems in focality, location, safety and its trend are discussed.

Humans↗

PubMed2001

[A preliminary study on ecological response of dominant tree species in Korean pine broadleaf forest at Changbai Mountain to soil water stress and their biomass allocation].

Pot culture experiments were conducted to examine the ecological response and biomass allocation of Pinus koraienes, Fraxinus mandshurica, Juglans mandshurica, Tilia amurensis, and Quercus mongolica. The five dominant species in the Korean pine-broadleaf forest at Changbai mountain. Their seedlings were grown under three different soil moistures, e.g., 85%-100% (CK), 65%-85% (MW) and 45%-65% (LW) of field water-holding capacity. The results showed that drought significantly decreased the individual leaf area, number of fine root, root length, and individual biomass of seedlings. The root proportions of T. amurensis and F. mandshurica increased with increasing soil water content, but the leaf proportion of J. mandshurica and Q. mongolica in MW treatment was higher than that of CK and LW. There was no significant difference in stem proportions of 5 tree species among different water stress treatments. The response of the biomass of 5 tree species to water stress was significant, the total biomass of T. amurensis, F. mandshurica, J. mandshurica and P. koraienes in MW and LW decreased by 32.8%, 43.6%, 26.2% and 23.8%, respectively, while that in Q. mongolica increased by 4.8%, indicating that Q. mogolica was the most drought-tolerent species among 5 tested species.

Biomass↗

PubMed2001

[Major inorganic compositions in fine and coarse particles of ambient aerosol at Qingdao].

Four times measurements of ambient aerosol were conducted from September, 1997 to August, 1998 at a coastal site of Qingdao. The results indicated that mass concentrations of aerosol mainly exist in fine particles(PM2.5, diameter less than 2.5 microns). The proportion of the fine particles in the heating period is much higher than that in the non-heating period. SO4(2-), NH4+, NO3-, K+ mainly exist in the fine particles while Na+, Cl-, Mg2+, Ca2+ mainly exist in the coarse particle, F-, Cl-, Br- mainly exist in the fine particles in the winter, but in the coarse particles in the summer, which reflects the influence of anthropogenic burning source and atmosphere temperature.

Aerosols↗

PubMed2001

[The effect of the hyper-erupted third molar on chewing movement].

OBJECTIVE: To investigate the effect of the hyper-erupted third molar contacting closely to the distal surface of the opposing second molar on the chewing movement. METHODS: Twenty-three university student volunteers, 11 with hyper-erupted third molar teeth and 12 with normal occlusion, were enrolled in present study. There were totally 6 unilateral hyper-erupted third molars (3 upper and 3 lower) and 5 bilateral hyper-erupted third molars (1 bilateral upper and 4 bilateral lower). No other significantly abnormal occlusal phenomenon was observed. Five gum-chewing cycles masticated with an each side were separately recorded by means of K6-I mandibular kinesiograph (MKG) and the chewing cycles were analyzed. Both three-dimensional amplitudes and the related velocities were automatically documented with the instrument. RESULTS: (1) The chewing graphs recorded on both frontal and horizontal planes in controls were typically smooth cycles with clearly occlusal phase tracings. On the sagital plane the opening and closing traces around intercuspal position (ICP) were usually overlapped with each other. (2) 63.6% frontal cycles of the subjects with hyper-erupted third molar had an obvious table (0.2 mm to 1.0 mm in width) around ICP, 50% horizontal cycles of the subjects had a 0.2 mm to 0.5 mm step near to ICP, 72.7% opening and closing traces on the sagital plane separated into anterior and posterior branches. The abnormal traces on the three different planes of the hyper-erupted third molar tooth group appeared to be related each other, implying that they might be caused by the same characteristics of occlusion, namely, the hyper-erupted third molar. (3) Subjects with hyper-erupted third molar masticated in more posterior direction, together with a higher chewing terminal velocity. CONCLUSIONS: The hyper-erupted third molar had a significant effect on the chewing cycles around ICP, as well as on the amplitude and velocity of chewing movement.

Adolescent↗

PubMed2001

[A novel antiapoptosis gene, survivin, bcl-2, p53 expression in cervical carcinomas].

OBJECTIVE: To study the expression of a novel inhibitor gene of apoptosis, survivin, in cervical carcinoma and its relationship with the expression of bcl-2, p53 genes. METHODS: Using streptavidin-biotin peroxidase (SP) method, we examined the expression of survivin, bcl-2 and p53 genes in 10 normal cervical tissues and 59 cervical carcinoma tissues. RESULTS: Survivin was expressed in 41 of 59 (69.5%) cases of cervical carcinomas. In contrast, normal cervical epithelium did not express survivin. Overexpression of survivin was related to the tumor grade and clinical stage. Survivin positive cases were strongly associated with bcl-2 expression (36/45, 80.0% versus 5 of 14 cases, P < 0.005) and p53 expression (33/43, 76.7% versus 8 of 16 cases, P < 0.05). CONCLUSIONS: Apoptosis inhibition by survivin, alone or in cooperation with bcl-2 and p53 may participate in the onset and progression of cervical carcinoma. Survivin could be a new diagnostic/therapeutic target in cervical cancer.

Adult↗

PubMed2001

Characterization of hemagglutinin gene of influenza A virus subtype H9N2.

OBJECTIVE: To determine the origin of human influenza A (H9N2) virus and the relationship among H9N2 strains isolated from different hosts, on the basis of molecular biology. METHODS: Viruses were passed in embryonated hen eggs, and virion RNA was extracted from allantoic fluid and reverse transcribed to synthesize cDNA. cDNA was amplified by PCR and the PCR product was purified with a purification kit. Afterwards RNA sequence analysis was performed by dideoxynucleotide chain termination and a cloning method. Finally, phylogenetic analysis of the sequencing data was performed with MegAlign (version 1.03) and Editseg (version 3.69) softwares. RESULTS: The amino acid sequences at the cleavage site between HA1 and HA2 domains of H9N2 viruses isolated in China are R-S-S-R. One pigeon strain contains seven potential glycosylation sites on the HA protein molecule, while all others have eight. There are 2 to 15 differences of amino acid sequences distributed at 24 different positions on the HA protein molecules among six H9N2 viruses. The H9N2 viruses with multiple lineages of HA genes were co-circulating in China recently. CONCLUSION: The highest possibility is that human influenza A (H9N2) virus was derived from Chicken H9N2 virus, and not derived from pigeon H9N2 virus. However, it is still unknown whether the H9N2 virus could transmit from person to person. The H9N2 viruses with multiple lineages of HA genes are co-circulating in China.

Amino Acid Sequence↗

PubMed2001

Replacement of the p16 gene in human ovarian cancer cells.

OBJECTIVE: To study the inhibitory effects of retrovirus-mediated p16 gene on the human ovarian cancer cell line CAOV3. METHODS: The recombinant eukaryotic expression vector pDOR-p16 containing exogenous human wt-p16 cDNA and vector with neomycin resistance gene only were introduced into a CAOV3 cell line which does not express p16 endogenously by lipofectamine-mediated gene transfection. By using polymerase chain reaction amplification, mRNA in situ hybridization and immunocytochemistry, the clones obtained were tested for their efficiency of transfection and effects of vector expression. Their biologic behavior was observed further. RESULTS: Exogenous wt-p16 was transferred into CAOV3 cells successfully and permanent expression was obtained. The growth rate of the transfected CAOV3 cells in regular medium and soft agar was inhibited, and the tumorigenicity in nude mice showed that two of four mice failed to form tumors, and the others developed tumors 7 to 14 days later than mice of the contrast group. The percentage of phase G1 cells increased and that of phase S cells decreased. Under electron microscope, the ultrastructural changes of the cells revealed necrosis and growth retardation. CONCLUSIONS: The p16 gene plays an important role in the generation and development of ovarian carcinoma. This study might provide experimental evidence for gene therapy in human ovarian cancer.

Animals↗

PubMed2001

Detection of human herpesvirus 8 DNA in acute leukemia patients.

OBJECTIVE: To determine the prevalence of human herpesvirus 8 (HHV-8) DNA in acute leukemia (AL) patients. METHODS: The presence of HHV-8 DNA sequences in peripheral blood mononuclear cells (PBMC) and bone marrow mononuclear cells (BMMC) from 50 AL patients was examined using polymerase chain reaction (PCR). Nine human hematopoietic cell lines and PBMC from 30 normal donors were also included. RESULTS: HHV-8 DNA sequences were detected in one case of acute myelogenous leukemia (AML). The specimens from the bone marrow aspirate, peripheral blood and serum of this patient were all positive. None of the normal donors and human hematopoietic cell lines showed evidence of HHV-8 DNA. CONCLUSION: The results suggest that the prevalence of HHV-8 is low in AL in China.

Acute Disease↗

PubMed2001

[Key technologies in image analysis of comparative genomic hybridization].

Comparative genomic hybridization has become a new technique in molecular-cytogenetics, and it has found significant applications in tumor pathology. Image analysis is an important part of comparative genomic hybridization. It analyzes the fluorescent images by many steps and finally determines whether there is any abnormality in the copy number of the test tumor tissue. This paper expatiates on the key steps in the image analysis of comparative genomic hybridization, including background correction, chromosome segmentation, chromosome axis determination, karyotyping and determining ratio profile. The future trend is also discussed.

Cytogenetics↗

PubMed2001

[Application of positron emission tomography in diagnosis and treatment of lung cancer].

OBJECTIVE: To determine the usefulness of positron emission tomography(PET) with fluoro-2-deoxyglucose (FDG-PET) in lung cancer. METHODS: Patients who presented between September 1999 and March 2000 with lung cancer or indeterminate lung lesions on chest CT scan were enrolled and underwent FDG-PET scanning. RESULTS: Of the 88 patients, 68 (77.3%) patients had malignancy and 20(22.7%) patients had a benign lesion. Of the 125 lung lesions, 80(64.0%) malignant lesions had a median standard uptake ratio (SUR) of 2.8(range 0-12.0), while 45(36.0%) benign lesions had a median SUR of 0(range 0-3.7). There was significant difference between the two groups. The diagnostic sensitivity and specificity of PET imaging for lung lesions were associated with the size of lesions but not with radiation or chemotherapy given before. The diagnostic specificity and accuracy of PET for lung lesions were significantly higher than those of CT scan. The sensitivity, specificity and accuracy of SUR method were 65.0%, 91.1% and 74.4% respectively and those of PET visual analysis were 95.0%, 95.6% and 95.2% respectively. The accuracy for lung lesions > or = 1.5 cm with SUR method was higher than that of lesions < 1.5 cm, being 93.8% and 62.3% respectively. The diagnostic sensitivity and accuracy of PET visual analysis for lymph node metastasis were significantly higher than those of CT scan. SUR was not correlated with the degree of cell differentiation, but it decreased significantly in small cell lung cancer after radiation or chemotherapy. CONCLUSIONS: PET is of advantage to the evaluation of lung lesions and diagnosis of lymph node metastasis in lung cancer. PET visual analysis is recommended in lung lesions after radiation or chemotherapy or with size < 1.5 cm in diameter.

Adult↗

PubMed2001

[Preliminary pharmacological study on polysaccharide from Urtica fissa].

OBJECTIVE: To study the pharmacological effects of the polysaccharide from Urtica fissa. METHODS: Pinna swelling induced by xylene in rats, footpad swelling induced by carageenin and immunity experiment were used. RESULTS: The polysaccharide from Urtica fissa could inhibit footpad swelling induced by carrageenin and the pinna swelling induced by xylene in rats. It could also quicken speed of clearing away carbon black of mouse. CONCLUSION: The polysaccharide has the significant effect of anti-inflammation and immunity enhancement.

Adjuvants, Immunologic↗

PubMed2001

Prospective survey on neurosurgical intensive care for patients with severe head injury.

OBJECTIVE: To prospectively compare the clinical outcome of intensive care therapy (ICT) with that of conventional care therapy (CCT) in severe head injured patients. METHODS: Patients with severe head injury were assigned randomly into Group ICT and Group CCT, 100 patients in each group. Patients in Group ICT accepted intensive care therapy in neurosurgical intensive care (NIC) unit for the first 2 weeks after admission, while patients in Group CCT accepted conventional care therapy in ordinary ward. The outcomes were evaluated 3 months after injury. RESULTS: There was a significant increase in good recovery (54%) (chi(2)=4.43, P<0.05) and significant decrease of death (25%) (chi(2)=4.50, P<0.05) in Group ICT compared to 39% and 39% in Group CCT respectively. The differences were also confirmed statistically in the following aspects: the patients under 50 years with good recovery pronounced a number increase (chi(2)=7.54, P<0.01), while the mortality in the same range of age was decreased in Group ICT (chi(2)=5.28, P<0.05). The mortality was reduced significantly in patients with GCS for 6-8 on admission (chi(2)=8.47, P<0.01) and in patients with the level of brain stem injured below mesencephalon (chi(2)=4.15, P<0.05). ICT would improve the outcome in patients undergoing conservative therapy only (chi(2)=13.13, P<0.01). CONCLUSIONS: NIC plays an important role in assessing the neurological state, guiding management, evaluating curative effect and estimating the outcome.

Adolescent↗