Biomedical subjects

M Zhang

Publications and source records attributed to M Zhang.

At least 271 records · Page 15Linked to original sources

PubMed2001

[Ultrasonic measurement of the elastic properties of goat condyles].

OBJECTIVE: The purpose of this experiment is to investigate the elastic properties of goat mandibular condyles and to provide basic constants for biomechanical study of temporomandibular joint. METHODS: A fresh goat mandible was adopted and the standard condyle specimen of 4 mm x 6 mm x 10 mm was obtained from it. The structure density of the condyle was determined according to Archimede's principle. The transmitting velocities of ultrasonic wave in different directions of goat condyles were measured by using the ultrasonic system, which was composed of a transmitting transducer of 1.25 MHz, a receiving transducer of 2.5 MHz, an ultrasonic analyzer (5052UA) and a digital storage oscilloscope (HP54601A). The elastic coefficients and technical constants could be calculated by elastic equations. RESULTS: The structural density of the sample and the wave velocities in different directions of the condyle were both obtained by direct measurement. And then, nine elastic coefficients and all of the technical constants of orthotropic condyles were calculated. CONCLUSION: 1. It is practicable to measure elastic properties of the condyle by using ultrasonic technique. 2. Goat condyles of the mandible are a type of anisotropic and linearly elastic material. 3. The direction perpendicular to the transverse ridge of the goat condyle has the highest Young's modulus. As to shear modulus, the direction along the transverse ridge shows the highest value.

Animals↗

PubMed2001

[Effects of fluid shear stress on PGE2 synthesis of primary osteoblast-like cells in rats].

OBJECTIVE: The purpose of this study is to study the function of PGE2 during the signal transduction in which fluid shear stress regulates the proliferation and differentiation of osteoblast-like cells. METHODS: The isolated rat primary osteoblast-like cells were exposed to fluid shear stress 0.12 mN/cm2 for 5, 10, 15, 30, 60 and 120 minutes respectively in a flow chamber. The release of PGE2 was examined. RESULTS: After exposure to fluid shear stress, the PGE2 synthesis of rat primary osteoblast-like cells increased significantly (P < 0.01) when compared with the control. After 10 minutes, the release of PGE2 began to increase significantly (P < 0.01) and the effect was maximal after 60 minutes (P < 0.01). CONCLUSION: PGE2 pathway may be one of the signal-transduction pathways which can transduce the fluid shear stress into osteoblast-like cells and then stimulate the bone remodeling.

Animals↗

PubMed2001

[Study on maxillofacial impact injury associated with brain injury].

OBJECTIVE: The purpose was to study the mechanism and the characteristics of brain damage associated with maxillofacial injury under the impacting load of middle face. METHODS: Eighteen rabbits were subjected to impacting on left middle face with pneumatic impact device, which were horizontally located on the ground. The impact velocities respectively were 4.77 m/s +/- 0.53 m/s (group A), 9.16 m/s +/- 0.65 m/s (group B) and 13.95 m/s +/- 0.67 m/s (group C). The acceleration of head and stress of encephalic was monitored during the impact period. The pathological characteristics of correlative tissues were examined in detail 6 hours after impacting. The contents of LPO, SOD and NO in blood and water in brain were measured at the same time. RESULTS: The contents of LPO and SOD in blood significantly increased along with the increasing of impact velocity (P < 0.05). The same pattern was observed in the changing of water content of brain (P < 0.05). But the contents of NO in blood reduced when the impact velocity increased (P < 0.05). The animals of group A showed single fracture of middle face bone, while Group B showed multiple fractures of middle face bone. Group C represented severe maxillofacial injury associated with brain damage. The pathological damage of brain became more serious along with the increase of impact velocity. The peak value of head acceleration and encephalic stress of group C were higher than that of group A and group B (P < 0.05). CONCLUSION: The responses of head acceleration and encephalic stress resulting from middle face impacting might play a key role in brain injury associated with maxillofacial injury.

Animals↗

PubMed2001

A study on the preservation of fresh amniotic membrane.

OBJECTIVE: To establish the standard preservation methods of fresh amniotic membrane for clinical use. METHODS: Human placentas were collected aseptically from selective caesarean sections in normal women in time. Amniotic or placental membrane were peeled and preserved in N. S, P. B. S or DMEM at 4 degrees C or cultured in DMEM at 37 degrees C, 5% CO2. Trypan-blue staining, light and electronic microscopy were observed every six hours after preservation. RESULTS: Seventy percent of amniotic epithelial cells survived after preservation in N.S for 6 hours, PBS 12 hours, DMEM 24 hours and 1 week in tissue culture. The amount of living epithelial cells maintained in placental membrane preservation was less than that in amniotic membrane preservation at the same time (t-test, P < 0.01). No collagen degeneration was found during preservation. CONCLUSION: Preservative solution and time will affect the maintenance time of fresh amniotic membrane greatly. Fresh amniotic membrane should be preserved within 6 hours in N. S, 12 hours in P. B. S, 24 hours in DMEM at 4 degrees C and 1 week in tissue culture for clinical use.

Adult↗

PubMed2001

[Effect of qidan tongmai tablet on glucose and lipid metabolism in patients with diabetes mellitus type 2].

OBJECTIVE: To study the effect of Qidan Tongmai tablet (QDTMT) on glucose and lipid metabolism in patients with diabetes mellitus (DM) type 2. METHODS: Patients of DM, with or without hyperlipidemia complication (HLC) were divided into 4 groups, Group A (33 cases without HLC) and B (33 cases with HLC) were treated by QDTMT, Group C (31 cases without HLC) and D (31 cases with HLC) were not treated by QDTMT. The treatment was carried out on the previous basic hypoglycemic treatment with a therapeutic course of 2 months. RESULTS: The levels of fasting glucose, 2 hrs postprandial blood glucose and glycosylated hemoglobin, as well as the levels of total cholesterol and triglyceride lowered, and the high density lipoprotein increased in Group A and B after treatment, as compared with those before treatment, the difference was significant (P < 0.01). While in Group C and D, the above-mentioned indexes were not changed significantly (P > 0.05). No apparent side-effect was found in the QDTMT treatment period. CONCLUSION: Besides regulating abnormal blood lipid, QDTMT has also a hypoglycemic effect in certain degree in patients with DM type 2.

Adult↗

PubMed2001

[Antifibrotic effects of genistein and quercetin in vitro].

AIM: To study the antifibrotic effects of genistein (GE) and quercetin (QU) on rat hepatic stellate HSC-T6 cell proliferation stimulated with platelet-derived growth factor (PDGF), collagen synthesis and type I procollagen messenger RNA (mRNA) expression stimulated with transforming growth factor beta 1 (TGF beta 1). METHODS: Cell proliferation was measured by crystal violet staining assay. Collagen synthesis was determined by 3H-proline incorporation assay. Type I procollagen mRNA level was determined by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: GE (25-70 mumol.L-1) and QU (6.25-50 mumol.L-1) concentration-dependently attenuated PDGF-drive HSC-T6 cell proliferative activity. TGF beta 1-stimulated collagen synthesis was also reduced. This was associated with a decrease of type I procollagen mRNA, indicating an effect at a pretranslational level. CONCLUSION: GE and QU may have therapeutic potential against liver fibrosis by regulating PDGF and TGF beta 1 actions.

Animals↗

PubMed2001

[Expression of apoptosis of the skin lesion and muscle from patients with dermatomyositis].

OBJECTIVE: This study inquired into the relationship between the influence of corticosteroid and the expression of apoptosis, Fas and Bcl-2 in muscle from patients with dermatomyositis (DM). METHODS: Corticosteroid was given to group A (10 DM cases) but not given to group B (12 DM cases). RESULTS: Apoptotic cells were detected in situ by terminal deoxynucleotidyl transferase-mediated-dUTP nick end labeling (TUNEL). Fas and Bcl-2 expressions was determined with the use of immunohistochemical staining in DM. The results showed that more expression of apoptosis in keratinocytes, muscle cells and lymphocytes were observed in group A. The apoptotic index (AI) of muscle cells and that of lymphocytes were more marked in group A than in group B (P < 0.05). Less apoptosis cells were observed in two weeks of treatment, and no correlation was found between apoptosis and the lesion of skin and muscle. CONCLUSION: The authors suggest that corticosteroid may play a role in inducing the apoptosis of keratinocytes, muscle cells and lymphocytes, which may be one of the therapeutic mechanisms of corticosteroid. The length of administering corticosteroid to the patients seems related to apoptosis.

Adult↗

PubMed2001

[Relationship between apoptosis and expression of Fas, bcl-2 and Ki-67 in condyloma acuminatum].

OBJECTIVE: This study inquired into the significance and relationship of apoptosis to the regulation and proliferation of condyloma acuminatum(CA). METHODS: Apoptotic cells were detected in situ by terminal deoxynucleotidyl transferase-mediated-dUTP nick end labeling (TUNEL). The detection of Fas, bcl-2 and Ki-67 expression was performed using immunohistochemical staining in 28 specimens of CA. RESULTS: Apoptotic cells were found in 24 cases (85.7%) in keratinocytes. All of the in 28 cases(100%) had Fas and Ki-67 positive expressions, but only 8 cases (28.6%) had bcl-2 mild or moderate expression. The disease severity (serious, moderate and mild) groups did not significantly differ in apoptotic index (AI), Fas, bcl-2 and Ki-67 positive expression (P > 0.05). There was positive correlation between AI and Fas(r = 0.866, P = 0.000). bcl-2 and Ki-67 were negatively correlated with AI (r = -0.416, P = 0.018; r = -0.475, P = 0.006). CONCLUSION: It is suggested that apoptosis in keratinocytes may play an important role in inhibiting the proliferation of virus, that Fas may be an upregulative factor and bcl-2 may be an inhibition factor to apoptosis, and that excessive Ki-67 expression may be associated with the acceleration of cell cycle.

Adaptor Proteins, Signal Transducing↗

PubMed2001

[Ultrastructure changes of the olfactory epithelium of the patients suffering from dysosmia caused by the chronic sinusitis].

OBJECTIVE: To observe the ultrastructural changes of olfactory epithelium (OE) in patients suffering from dysosmia caused by chronic sinusitis. METHODS: The specimens of olfactory epithelium were obtained from 35 patients operated for chronic sinusitis accompanied by dysosmia. According to the results of light microscope (LM) examination, the OE was divided into three groups by the types of pathological changes: normal, atrophic and respiratory epithelium metaplasia(REM). Transmission electron microscope was used to observe the ultrastructural changes of each group. RESULTS: Under the LM, the surface ultrastructure of the OE showed some abnormal changes: (1) surface microvillus of the supporting cells disappeared; (2) olfactory vesicle changed their shape due to vacuolization; (3) disappearance of canaliculus structure in the olfactory vesicle; (4) the olfactory cilia changed the shape or reduced; some of the reduced cilia underwent metaplasia. The ultrastructural changes of atrophic OE included: (1) minor and moderate atrophy: the organelles and the membrane-limited electron dense vesicles on the upper section of the supporting cells obviously decreased or disappeared, even underwent vacuolization. The basic cell degenerated; (2) serious atrophy: the turbidity of the cell structure, even double cell structure, the nuclei of the cell aggregated as the plaque and vesiculose change or karyopyknosis. As for the cytoplasm, there were the dilation of the ERs, turgidity of the mitochondrion, the disarrangement, diminution and vacuolization. Fasciculate cilia were distributed separately in the REM group. CONCLUSION: There is a positive relationship between the atrophy degree and the degree of the abnormal ultrastructural changes of the OE. The ultrastructural changes of OE in patients suffering from dysosmia caused by chronic sinusitis may provide reference for assessment of the treatment of dysosmia.

Adult↗

PubMed2001

[Studies on polysaccharide alkaloids and minerals from Dendrobium moniliforme (L.) Sw].

OBJECTIVE: To explore contents of active substances in different part of Dendrobium monilifrome and the quality influenced by different drying processes. METHOD: Contents of alkaloids and polysaccharides in upper, middle, lower-stem and root part of Dendrobium moniliforme were determined by uv-spectrophotometer method. Contents of essential trace elements were determined by ICP method. RESULT: Contents of polysaccharides and alkaloids were highest in the upper-stem of D. montiliforme. Contents of active substances in different part of D. moniliforme were unequal. Distributions of polysaccharides and alkaloids in different parts were greatly influenced by drying procedures. CONCLUSION: Dendrobium moniliforme has higher contents of active ingredients, such as essential tract elements, alkaloids and polysaccharides. The ideal drying process after harvesting is to be the way dried by fire at a high temperature and desiccated at a temperature of 60 degreeC.

Alkaloids↗

PubMed2001

[Constituents of Liguliria vellerea (Franch.) Hand-Mazz].

OBJECTIVE: To study the chemical constituents of Ligularia vellerea. METHOD: The compounds were isolated by column chromatography, and the structures were identified by NMR spectral data and other methods. RESULT AND CONCLUSION: Seven compounds were isolated and identified as 4-hydroxyacetophenone, 8 alpha-hydroxy-7(11)-eremophilen-12, 8 beta-olide, umbelliferone, tiglic acid, 6 beta-hydroxy-7(11)-eremophilen-12, 8 alpha-olide, daucosterin, beta-sitosterol and stigmasterol. All the compounds were isolated for the first time from this plant.

Acetophenones↗

PubMed2001

[Cluster analysis of Dendrobium by RAPD and design of specific primer for Dendrobium candidum].

OBJECTIVE: To analyze the genetic relationship of Dendrobium and design a specific primer to differentiate Dendrobium candidum effectively. METHOD: Random amplified polymorphic DNA (RAPD) technique was used to analyze the genetic relationships of 26 species of Dendrobium and one species of Ephemerantha. Dendrogram was constructed by UPGMA. According to the sequence of DNA fragment selected, Sangon 18 primer had been extended from 3' extreme to 20 bp in order to form a specific primer. RESULT AND CONCLUSION: This primer can be used to distinguish Dendrobium candidum from other Dendrobium effectively. Such a technique provides a new way for the identification of Chinese traditional medicines.

Cluster Analysis↗

PubMed2001

[Fudenine, relative to blood glucose-control, is a novel membrane protein].

OBJECTIVE: To determine whether Fudenine is a novel membrane protein. METHODS: Green fluorescence protein(GFP) was used to localize Fudenine in vivo. GFP, as a control, was targeted to cytoplasm. Epithelial cell, CBRH7919, and non-epithelial cell, L-6TG, were cultured and transiently transfected by using the lipofectamine reagent. After 48 h, intact cells were examined with fluorescence microscope for Fudenine. RESULTS: Reporter plasmid pEGFP-N1, as a control, was expressed and localized to cytoplasm. But Fudenine, driven by the cytomegalovirus promoterenhancer contained in the pEGFP-N1 vector, was overexpressed and targeted to cellular membrane. CONCLUSIONS: Fudenine is a novel membrane protein. It may play the similar role with its homologues AC133 antigen and prominin in human and mouse, respectively. It might be involved in signaling transduction and regulate blood glucose metabolism in vivo.

AC133 Antigen↗

PubMed2001

[Rapid synthesis and fluorescent spectra of the phosphor CaS:Eu2+ in a microwave field].

In this paper, the phosphors with CaS as the host and doped with Eu2+ ion were synthesized in a microwave field at the first time. The influence of the different concentrations of Eu2+ ion on fluorescent properties of the phosphors CaS:Eu2+ was discussed. The experimental results of SEM show that the crystallite structures of the CaS:Eu2+ with different shapes (such as cubic, spherical and rod) and different crystal sizes (100-1,500 nm), for example, nano-scale, submicron-scale or micron-scale can be obtained when doping different concentrations of Eu2+ ion. The fluorescent intensity of the sphere phosphor CaS:Eu2+ is the strongest under the excitation at 254 nm.

Calcium Sulfate↗

PubMed2001

[A comparative study of craniofacial morphologic differences between groups with shallow and deep antegonial notch depth].

OBJECTIVE: To evaluate the correlation between craniofacial morphology and antegonial notch depth of the mandible. METHODS: 42 patients of ear ly permanent dentition from Nanchang city, 21 with shallow and 21 with deep antegonial notch were selected. Lateral cephalometric film before treatment were taken. Hard tissue angular and linear measurement were performed. The correlation between antegonial notch depth and craniofacial morphology were analysed statistically. RESULTS: The angular measurements of SN-GoGn, S-ArGo, FH-GoMe,and ANS-Xi-Pm were significantly greater in the deep antegonial notch group. Other angles as SNB, SNP-BaN-CCGn, FH-NPg and MD-AA were significantly greater in the shallow antegonial notch group. For the linear measurements, those items as N-Me, ANS-Me,Convexity and LM-GoGn were significantly greater in the deep antegonial notch group. CONCLUSION: The deep antegonial notch group showed steeper mandibular plane, smaller chin, greater anterior facial height and gonial angle, and has a mandible with more backward and downward growth.

English Abstract↗

PubMed2001

[The cytotoxic effect of a low density lipoprotein delivered aclarubicin on leukemia cells].

OBJECTIVE: To investigate the feasibility and effectiveness of low density lipoprotein (LDL) particles as a carrier of a lipophilic anthracycline drug aclarubicin (ACR) for targeting delivery to an acute monocytic leukemia cell line THP-1. METHODS: LDL-ACR complex was prepared by incubating LDL with ACR. The intracellular ACR content was assayed fluorometrically. Cytotoxicity was studied by cell protein measurement and 3H-TdR incorporation test. RESULTS: Intracellular accumulation of LDL-ACR was reduced when THP-1 cells were incubated in the presence of native LDL, but methylated LDL had no effect on the cellular LDL-ACR accumulation. The LDL-ACR complex caused a greater inhibition of the growth of THP-1 cells than that of normal bone marrow nucleated cells. The cellular accumulation of LDL-ACR complex was much more than that of free ACR. The 3H-TdR incorporation test showed that the complex was more effective in the inhibition of DNA synthesis than that of the free drug. CONCLUSION: The potency of ACR to tumor cells increased and its toxicity to normal cells decreased when LDL was used as a carrier.

Aclarubicin↗

PubMed2001

[Construction and expression of single chain Fv antibody against human bladder carcinoma].

OBJECTIVE: To construct and express single chain Fv antibody against human bladder carcinoma, which was expected to have advantages in targeted diagnosis and therapy with the characteristics of lower immunogenicity. METHODS: Hybridoma BDI-1 cell, which secreted a monoclonal antibody against human bladder carcinoma, was used to isolate total RNA. By reverse transcription, the cDNA was synthesized and used as templates for amplifying the immunoglobulin heavy-and light-chain variable region genes by polymerase chain reaction (PCR). The amplified DNA was ligated into a sequencing vector pUC19 and sequenced with Sanger's method. The VH and VL genes were inserted into expression vector pFUW80. By inducing, the ScFv antibodies were expressed and secreted from Escherichia coli. Binding activities against the bladder carcinoma cells were detected by ELISA. The 5 x his-tagged ScFv antibodies were purified on IDA-Ni2+ resin by immobilized metal chelate affinity chromatography (IMAC). The purified ScFv antibodies were analyzed by SDS-PAGE. RESULTS: A full-length of VH and VL genes was 366 and 324 base pairs respectively. Comparing with other published sequences, the VH gene was a member of mouse heavy-chain VH subgroup II and originated from re-arrangement of VH, Dsp2.2 and JH4; the VL gene was VK subgroup IV and from Vk and Jk4. The ScFv antibodies could inhibit 84% of the antigen binding activity of original McAb BDI-1. The purified ScFv antibodies gave a single major band (Mr-29 000) on SDS-PAGE. CONCLUSION: The single chain Fv antibody against human bladder carcinoma was successfully constructed and expressed.

Amino Acid Sequence↗

PubMed2000

Role of vagus nerve signaling in CNI-1493-mediated suppression of acute inflammation.

CNI-1493 is a potent anti-inflammatory agent, which deactivates macrophages and inhibits the synthesis of proinflammatory mediators. The objective of the present study was to identify the role of the central nervous system (CNS) and efferent vagus nerve signaling in CNI-1493-mediated modulation of acute inflammation in the periphery. CNI-1493 was administered either intracerebroventricularly (i.c.v., 0.1-1,000 ng/kg) or intravenously (i.v., 5 mg/kg) in anesthetized rats subjected to a standard model of acute inflammation (subcutaneous (s.c.) injection of carrageenan). I.c.v. CNI-1493 significantly suppressed carrageenan-induced paw edema, even in doses at least 6-logs lower than those required for a systemic effect. Bilateral cervical vagotomy or atropine blockade (1 mg/kg/h) abrogated the anti-inflammatory effects of CNI-1493 (1 microg/kg, i.c.v. or 5 mg/kg, i.v.), indicating that the intact vagus nerve is required for CNI-1493 activity. Recording of the efferent vagus nerve activity revealed an increase in discharge rate starting at 3-4 min after CNI-1493 administration (5 mg/kg, i.v.) and lasting for 10-14 min (control activity=87+/-5.4 impulses/s versus CNI-1493-induced activity= 229+/-6.7 impulses/s). Modulation of efferent vagus nerve activity by electrical stimulation (5 V, 2 ms, 1 Hz) of the transected peripheral vagus nerve for 20 min (10 min before carrageenan administration and 10 min after) also prevented the development of acute inflammation. Local administration of the vagus nerve neurotransmitter, acetylcholine (4 microg/kg, s.c.), or cholinergic agonists into the site of carrageenan-injection also inhibited acute inflammation. These results now identify a previously unrecognized role of efferent vagus nerve activity in mediating the central action of an anti-inflammatory agent.

Acetylcholine↗