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Biomedical subjects

H Ma

Publications and source records attributed to H Ma.

At least 199 records · Page 11Linked to original sources
PubMed1997

Specific interactions between the K domains of AG and AGLs, members of the MADS domain family of DNA binding proteins.

MADS domain (for MCM1, AG, DEFA and SRF) proteins are regulatory proteins found in all major eukaryotic kingdoms. Plant MADS domain regulatory proteins have a region of moderate sequence similarity that has been designated as the K domain, and its predicted coiled-coil structure suggests a role in establishing a protein-protein interaction. In vivo studies with the Arabidopsis AGAMOUS (AG) protein have indicated that the K domain is important for AG function. Using a bait fusion protein containing the K domain and the C-terminal region of AG in a yeast two-hybrid selection, 156 clones that encode potential AG-interacting proteins were identified. These clones each encode one of four highly related MADS domain proteins: AGL2, AGL4, AGL6 and AGL9. Additional analysis showed that the K domain of AG alone was able to bind the K domains of these AGLs. This binding was further confirmed by immunoprecipitation experiments using in vitro synthesized AG and AGL K domains. These results strongly suggest that AG interacts with AGL2, AGL4, AGL6 and AGL9 in vivo. Based on these results and previous observations, it is proposed that the AG function requires interaction with at least one of these AGL proteins, and such interactions contribute to the functional specificity of the AG protein.

AGAMOUS Protein, Arabidopsis↗
PubMed1997

FON1, an Arabidopsis gene that terminates floral meristem activity and controls flower organ number.

A novel gene that regulates floral meristem activity and controls floral organ number was identified in Arabidopsis and is designated FON1 (for FLORAL ORGAN NUMBER1). The fon1 mutants exhibit normal vegetative development and produce normal inflorescence meristems and immature flowers before stage 6. fon1 flowers become visibly different from wild-type flowers at stage 6, when the third-whorl stamen primordia have formed. The fon1 floral meristem functions longer than does that of the wild type: after the outer three-whorl organ primordia have initiated, the remaining central floral meristem continues to produce additional stamen primordia interior to the third whorl. Prolonged fon1 floral meristem activity also results in an increased number of carpels. The clavata (clv) mutations are known to affect floral meristem activity. We have analyzed the clv1 fon1, clv2 fon1, and clv3 fon1 double mutants. These double mutants all have similar phenotypes, with more stamens and carpels than either fon1 or clv single mutants. This indicates that FON1 and CLV genes function in different pathways to control the number of third- and fourth-whorl floral organs. In addition, to test for possible interactions between FON1 and other floral regulatory genes, we have constructed and analyzed the relevant double mutants. Our results suggest that FON1 does not interact with TERMINAL FLOWER1, APETALA1, APETALA2, or UNUSUAL FLORAL ORGAN. In contrast, normal LEAFY function is required for the expression of fon1 phenotypes. In addition, FON1 and AGAMOUS both seem to affect the domain of APETALA3 function, which also affects the formation of stamen-carpel chimera due to fon1 mutations. Finally, genetic analysis suggests that FON1 interacts with SUPERMAN, which also regulates floral meristem activity.

Arabidopsis↗
PubMed1997

Determination of Arabidopsis floral meristem identity by AGAMOUS.

Determinate growth of floral meristems in Arabidopsis requires the function of the floral regulatory gene AGAMOUS (AG). Expression of AG mRNA in the central region of floral meristems relies on the partially overlapping functions of the LEAFY (LFY) and APETALA1 (AP1) genes, which promote initial floral meristem identity. Here, we provide evidence that AG function is required for the final definition of floral meristem identity and that constitutive AG function can promote, independent of LFY and AP1 functions, the determinate floral state in the center of reproductive meristems. Loss-of-function analysis showed that the indeterminate central region of the ag mutant floral meristem undergoes conversion to an inflorescence meristem when long-day-dependent flowering stimulus is removed. Furthermore, gain-of-function analysis demonstrated that ectopic AG function results in precocious flowering and the formation of terminal flowers at apices of both the primary inflorescence and axillary branches of transgenic Arabidopsis plants in which AG expression is under the control of the 35S promoter from cauliflower mosaic virus. Similar phenotypes were also observed in lfy ap1 double mutants carrying a 35S-AG transgene. Together, these results indicate that AG is a principal developmental switch that controls the transition of meristem activity from indeterminate to determinate.

AGAMOUS Protein, Arabidopsis↗
PubMed1997

[Comparison of plasma thyroxin and insulin concentrations between 10-day old layer and broiler chickens].

In this study both sexes of 10 day old layer and broiler chickens were used to investigate plasma circulating concentrations of 3,3'-5-triiodothyronine (T3), thyroxine (T4) and insulin by using the radioimmunoassay (RIA) methods. The results were as follows: serum T3 concentration was higher in broilers than that in layers (P < 0.01), especially a significant difference between male strains was seen in this experiment (P < 0.001), and the levels of plasma insulin was significantly higher in male broilers than that in male layers (P < 0.001), however, no clear differences in plasma T4 was seen between strains and sexes (P > 0.05). In addition, there were sex differences in T3 and insulin levels in layers, that is to say, those in the female layers was higher than those in the male layers, but no clear deifference was seen between sexes in broilers. A significant positive correlation between T3, insulin and their weight gained (P < 0.05). The results suggest that the levels of serum T3 and Insulin may influence the various growth rate during early posthatch development in layers and broilers.

Animals↗
PubMed1997

[Significance of surgical treatment of bursting fracture with CT estimation analysis of the anatomy of pedicle of vertebral arch].

Using CT analysis of 3-D anatomical data of the pedicle of the vertebral arch as a guideline, we standardized the pedicle screw insertion technique. Fourty-six bursting fracture cases were treated using a AF 3-D pedicle screw system with the standard technique and followed up for over 12 months. Comparision was made with the former non-standard technique performed in 72 cases. The results showed that each screw reached the maximum depth with an accurate angle. Comparision of the former non-standard technique showed a significant difference between the two groups. 46 bursting fracture cases obtained anatomical reduction in 3-D and rigid fixation after follow-up for 12 months. Pedicle screw, inserted through the pedicle anatomical axis can reach the maximum depth, that will achieve best stability and ideal clinical result. CT analysis supplies reliable individual data for standardization of pedicle screw insertion.

Adolescent↗
PubMed1997

[An approach to the binocular vision of traumatic cataract after intraocular lens implantation].

OBJECTIVE: To explore the recovery of binocular vision and stereoacuity of monocular cataract extraction after posterior chamber intraocular lens (IOL) implantation. METHODS: After extraction of traumatic cataract, primary or secondary posterior chamber IOL implantation was performed on 36 cases. The naked vision, corrected vision and binocular dioptric state were observed pre- and post-operatively. Synoptophore, Bogolini striated glasses, barred reading and Tiemus stereoscopic vision picture were applied. RESULTS: The visual acuities of 36 cases were significantly improved postoperatively, the corrected visual acuities of 24 cases (66.7%) were over 4.95 and 30 cases were over 4.8 after three months. The binocular and stereoscopic vision of 21 cases was recovered well. CONCLUSION: IOL implantation should be performed early after extraction of monocular cataract in order to improve the recovery and development of binocular vision and stereoacuity, particularly in children.

Adolescent↗
PubMed1997

[Transposition of the pedicled gluteus maximum myocutaneous flap for the repair of huge sacral pressure sores].

From 1986 to 1992, the authors repaired huge sacral pressure sores in 14 cases using the pedicled gluteus maximum myocutaneous flap. The treatment was completed in one stage and the results were satisfactory in all the cases during the follow-up period of 6 months to 7 years. No recurrence occurred. The authors concluded that the method is a good treatment for persistent sacral pressure sores.

Adolescent↗
PubMed1997

[Preparation of monoclonal antibodies to barley yellow mosaic virus].

Using hybridoma techniques, six hybridoma celllines: 4D6, 4D4, 4F10, 3H6, 3H8 and 4E9 secreting monoclonal antibodies to Shanghai Isolate of Barley yellow mosaic virus (BaYMV) were prepared by fusion between myeloma cells NS-1 and spleen cells of BALB/C mouse immunized with BaYMV. The subclasses of monoclonal antibodies obtained belong to IgG2a. The cross-reaction test with different viruses (SMV, TMV and three isolates of TuMV) showed that six monoclonal antibodies were specific to BaYMV. The titers of six monoclonal antibodies to BaYMV in their cell cultured supernatauts were 1:1-5 x 10(4), and that of 4F10 in ascitic fluid was 1:6.4 x 10(5) by using indirected ELISA test respectively.

English Abstract↗
PubMed1997

[Experimental study of distribution of stress and strain on pelvis in normal Chinese adult].

To approach the biomechanical properties of pelvis in normal Chinese adult, an intact pelvis taken from fresh healthy male cadaver after sudden death was used in this study. The pelvis joined up with lumber4, 5 and proximal segment of femurs. After appropriate management of the specimen, the loads in the simulated test (stand position of normal adult) are 300 N, 600 N and 900 N. With strain electric measuring apparatus, the distribution of stress and strain, and the actual linear strain of every measuring point are obtained. Data processing was performed on computer. The main stress sigma 1, sigma 2 and their direction angles were acquired. The results of the simulated test demonstrated that the stress of iliac bone adjacent to sacro-iliac articulation was maximum in all measuring points. The linear strain values of 0 degree direction parallel with coronal section were negative in majority, but those of 45 degrees and 90 degrees direction vertical with coronal section were positive in majority. So the distribution of the linear strain of pelvis should be very complicated. When 900 N weight acted on the pelvis, the maximum main stress sigma max = 0.269-20.01 MPa and the minimum main stress sigma min = -0.095(-)-16.56 MPa. The angle of the maximum main stress with coronal section did not exceed 4 degrees.

Adult↗
PubMed1997

[Transfer and expression of rh-SCF gene in human hematopoietic stem/progenitor cells].

OBJECTIVE: To explore the transfer and expression of recombinant human stem cell factor (rh-SCF) gene in human hematopoietic stem/progenitor cell. METHODS: pLXSN-SCF, a recombinant retrovirus vector of soluble human SCF gene, was constructed by recombinant gene technique. The recombinant plasmid was introduced into virus packaging cells psi2 and PA317 by lipofectin-mediated DNA transfection, and PA317/SCF, the recombinant virus producing cell, was obtained by G418 screening [the virus potency was (2.4-8.5) x 10(5) CFU/ml]. Then, human hematopoietic stem/progenitor cells were transfected with PA317/SCF. The transfer and expression of human SCF gene were assayed by PCR, APAAP immunohistochemical staining and chemoluminance-direct ELISA. RESULTS AND CONCLUSION: retrovirus-mediated rh-SCF gene was successfully transferred and expressed in human hematopoietic stem/progenitor cells.

Animals↗
PubMed1997

[Determination of Ni, Al, Mn and Si in copper based alloy by high current and microsecond pulsed glow discharge optical emission spectrometry].

The determination of Ni, Al, Mn and Si in copper based alloy by high current and microsecond pulsed (HCMSP) glow discharge optical emission spectrometry (GD-OES) has been reported. With the laboratory built experiment set-up, the factors effecting analytical performance have been studied. The results of sample analysis are in good agreements with the recommendation values, and the stansard deviation for six determinations were 2.66% for Ni, 2.17% for Mn, 6.02% for Si, 1.00% for Al respectively.

English Abstract↗
PubMed1997

Construction of a human heart cDNA library and identification of cardiovascular based genes (CVBest).

The availability of high quality cDNA libraries is often crucial to the successful identification and characterization of genes. The concepts and potential pitfalls of constructing cDNA libraries are presented. Various applications requiring high quality cDNA libraries are outlined, including large-scale single pass sequencing of cDNA clones to generate expressed sequence tags (ESTs) and differential screening of cDNA libraries. The usefulness of combining such approaches for the discovery of novel disease-related and cardiovascular-based ESTs (CVBest) is discussed.

Base Sequence↗
PubMed1997

Degranulation of cutaneous mast cells induces transendothelial transport and local accumulation of plasma LDL in rat skin in vivo.

In severe hypercholesterolemia and sometimes even in normolipemia, lipoprotein-derived cholesterol accumulates in the skin, forming xanthomas, but the local factors triggering this accumulation are not known. We therefore studied the effect of immunoglobulin E (IgE)-mediated stimulation of cutaneous mast cells on the transport of low density lipoprotein (LDL) from plasma to skin during the passive cutaneous anaphylaxis (PCA) reaction in rats. PCA sites were produced in rats by giving intracutaneous injections of rat serum containing high levels of IgE antibodies against ovalbumin. When ovalbumin was then injected intravenously into the rats, the skin histamine content at the sensitized skin sites decreased, reflecting degranulation of the passively sensitized (IgE-containing) mast cells at these sites, with ensuing release of histamine from the mast cells. Concomitant intravenous injection of increasing amounts of human [14C]sucrose-LDL led to rapid and dose-dependent increases in the skin [14C]sucrose-LDL content. These (maximally about 40-fold) increases were strictly localized to the PCA reaction sites: no such increase in [14C]sucrose-LDL content was observed in nonsensitized skin areas or in any other tissue of the rats. The increase in skin [14C]sucrose-LDL content could be blocked (by about 80%) with a combination of H1 and H2 receptor antagonists, and could be mimicked by intradermal injection of histamine. This study demonstrates an increase in plasma LDL influx into the skin at sites where mast cells are stimulated, and so suggests that mast cells play a role in the accumulation of LDL cholesterol that occurs in the skin when xanthomas form.

Animals↗
PubMed1997

Study on stress distribution of the condyle.

OBJECTIVE: To investigate the internal state of stress distribution in healthy human condyles and to offer some references for application of the temporomandibular joint (TMJ) biomechanics. METHODS: Six male volunteers were selected to perform CT examination of the TMJ with 1.5 mm-thick sections at 1.5 mm intervals. Three dimensional image reconstruction of the joint was performed in the SUN workstation and the CT data were converted into the decimal system. The three dimensional finite element model mesh generation resulted from 1188 elements and 264 nodes in each condyle. Stress calculation was performed with SAP-V program, and the results were converted into mechanical density scalar. During the study, the internal state of stress distribution on each side condyle in every subject was analysed on the basis of loading on the anterior articular surface of the condyle. RESULTS: Stress was concentrated in the anterior articular surface of the condyle and was highest at the loading point. The condylar cortical bone was the main load-bearing area. The level of stress distribution in the cancellous bone of the condyle was very low. Near condylar neck stress was well-distributed on the cortical. The internal state of stress was essentially symmetrical on the same cuts of both side condyles. CONCLUSIONS: The results showed that three dimensional finite element analysis may indicate the internal state of stress distribution in the condyle, suggesting that a combination of the three dimensional finite element methods and the three dimensional imaging technique may be a useful means for diagnosis and treatment of TMJ diseases.

Adult↗
PubMed1997

[Subperiosteal endoscopic forehead facelifting].

The use of endoscopic techniques in facelifts has had a significant effect in recent two years. To reduce operation complications and trauma, the authors performed 31 endoscopic forehead rejuvenation procedures with corrugator-procerus resection and eyebrow elevation at a desired level in Chirurgie Esthetique Europeenne in Strasbourg, France from January to November 1995. Three to six months' follow-up revealed satisfactory operation results. Subperiosteal endoscopic forehead facelifting using resection and elevation of the muscle of the eyebrow is one of the best operations for facelifting.

Adult↗