PubMed Health⌕ Search

Biomedical subjects

H Chen

Publications and source records attributed to H Chen.

At least 703 records · Page 39Linked to original sources
PubMed1999

[Detection of bcr/abl gene expression on bone marrow cell colonies in chronic myelogenous leukemia by reverse transcriptase-polymerase chain reaction].

The t(9;22) (q34;q11) between abl and bcr genes plays a pivotal role in the diagnosis and pathogenesis of chronic myelogenous leukemia(CML). To explore the bcr/abl fusion mRNA expression on hematopoietic precursors, reverse transcriptase-polymerase chain reaction(RT-PCR) was applied to detect bcr/abl mRNA expression on bone marrow cell colonies. Meanwhile, bcr/abl mRNA expressions on 14- or 28-day colonies using HPP-CFC and CFU-GM semisolid agar culture assay were also determined in 4 cases of confirmed Ph-positive CML by karyotyping analysis. The results showed that the bcr/abl mRNA expressions on 14-day colonies and some 14- or 28-day colonies detected singly were positive at presentation by RT-PCR, in agreement with results by karyotype analysis. Thus, a sensitive and powerful technique was offered for studying gene expression on hematopoietic precursors, diagnosis and therapeutic monitoring of CML. Furthermore, this can be used as an ideal method for revealing molecular mechanisms of pathogenesis of CML and screening anti-CML drugs.

Adult↗
PubMed1999

[Cloning of a new cDNA: responded to all-trans retinoic acid in HL-60 cell differentiation].

In this paper a new type of cDNA fragment named as W-1 gene was first cloned and sequenced from ATRA induced HL-60 cells by using differential display PCR (DD-PCR) and DNA sequencing techniques. These differentially expressing products of the gene responding to ATRA were further confirmed by Northern blotting analysis. The results showed that the expressing level of this gene induced by ATRA (10(-6) mol.L-1) for 16 hrs was much higher than that in the control HL-60 cells, but its expression in HL-60 was reduced to an unestimable level after induction of ATRA (10(-6) mol.L-1) for 24 hrs. It suggests that ATRA may increase the expression of W-1 gene during the early stage of HL-60 cell differentiation. The exact mechanism of action is being studied further.

Antineoplastic Agents↗
PubMed1999

[Reinnervation of skin flap by end-to-side neuro-anastomosis in the repair of soft tissue defect of heel].

OBJECTIVE: The repair of soft tissue defect of heel by traditional operation did not restore the sensation of the heel. METHODS: In order to solve this problem, the saphenous neurovascular skin flap reinnervated by end-to-side neuro-anastomosis was designed and 3 male patients with soft tissue defects of the heel were so treated. Grossgraft of saphenous neurovascular skin flap was employed for repairing the soft tissue defects of heel and the pedicle was divided at 21 days after operation. The end-to-side neuro-anastomosis was used to reinnervate not only the skim flap, but also the skin area of the medial malleolus, medial aspect of the foot and the big toe of the donor limb. RESULTS: After follow-up of 6-12 months, the walking and weight bearing functions of the affected limbs were good, the contour of the grafted area was satisfactory, and the recovery of sensation of the skin flap, the medial malleolus, the medial aspect of the foot and the big toe was observed. CONCLUSION: 1. Crossgraft of the saphenous skin flap was an effective method to repair the soft tissue defect of the heel; 2. End-to-side neuro-anastomosis could restore the sensation of the skin flap.

Adolescent↗
PubMed1999

[Activation of neutrophil and its relation to neutrophil-endothelial cell adherence].

Neutrophil was activated by chemotactic tripeptide N-formyl-methionyl-leucyl-phenylalanine(fMLP) of different concentration. The activation rate was tested by the method of nitroblue tetrazolium reduction. Using flow chamber system, we quantitatively studied the properties of neutrophil adhesion to human umbilical vein endothelial cell (HUVEC) under different shear stress. The results showed that the activation rate of neutrophil significantly increased with increase of fMLP concentration that the adhesion rate of neutrophil pretreated with fMLP decreased with the gradual increase of shear stress, such a change was also found in the control group; and that the adhesion rate of neutrophil to HUVEC increased with the increase of activation rate of neutrophil, but the adhesion rate had a tendency to decrease when shear stress increased. These indicated that shear stress induced by bloodstream might play an important role in inhibiting neutrophil-endothelial cell adherence in vivo and the enhanced activation of neutrophil could increase neutrophil-endothelial cell adherence.

Cell Adhesion↗
PubMed1999

[Study of the high polymorphism STR locus-FGA in Chinese population].

Population genetic study of the complicated STR locus-FGA was performed by the method of PCR in Han population samples. A total of 21 different alleles including 7 interalleles and 63 different genotypes were observed in 349 unrelated individuals. The observed genotype discrimination showed no significant deviation from Hardy-Weinberg equilibrium and 51 family studies showed no mutation. According to the results obtained in this study(DP = 0.9612, PE = 0.7007, PIC = 0.8333), this system can be used as an useful means in forensic identification of both criminal and paternity case.

Asian People↗
PubMed1999

[Polymorphic study of CSF1PO locus in Han population in Wuhan].

Using the primers designed by Yoshida, the amplified fragment length polymorphism of the STR locus CSF1PO was studied. 8 alleles were determined from 312 unrelated individuals of Han population living in Wuhan. Sensitivity and suitability of the PCR-STR typing using Yoshida's primers were compared with the one using Hammond's. Results proved that Yoshida's method were more suitable in forensic identification than that of Hammond, especially in the typing of severely degraded DNA samples.

Asian People↗
PubMed1999

[Recombinant Salmonella typhimurium anticaries vaccine. I. Sequence of Streptococcus mutans surface protein pac gene's upstream].

OBJECTIVE: To sequence the Streptococcus mutans surface protein pac gene's upstream. METHODS: The PCR autosequence kit and autosequence instrument ABI310 were used for sequence. RESULTS: The 517 base pairs sequence of the pac gene's upstream is sequenced. CONCLUSION: The sequence of pac gene's upstream will provide useful information to construct the recombinant Salmonella typhimurium anticaries vaccine.

Antigens, Surface↗
PubMed1999

[Radiofrequency treatment of ethmoidal nerve with allergic rhinitis under nasal endoscopy].

OBJECTIVE: To study the effect of radiofrequency treatment of ethmoidal nerve on allergic rhinitis. METHOD: Eighty-eight cases of allergic rhinitis were treated with ethmoidal nerve radiofrequency under nasal endoscopy. RESULT: It showed marked effectiveness in 73 cases (83.0%), immprovement in 11 cases (12.5%) and failed in 4 cases (4.5%) in one year follow-up. The overall effective rate was 95.5%. CONCLUSION: This result indicated that it is a choice for treating allergic rhinitis to apply ethmoidal nerve radiofrequency under nasal endoscopy.

Adolescent↗
PubMed1999

[Applied anatomy on musclebone flap of hyoideumomohyoid to renovate vocal fold].

OBJECTIVE: In order to provide anatomical basis for renovating vocal fold with muscle-bone flap of hyoideum-omohyoid. METHOD: It was measured that the anatomical structure correlative with superior belly of hyoideum-omohyoid, artery, vein and nerve of the muscle and vocal fold morphosis by 26(52 sides) cephalocevical sample dissection. RESULT: It was observed that the muscle is 74.8 mm in length, 8.4 mm in width of starting part, 9.6 mm in width of middle part, 4.4 mm in width of tendon part. Its blood supply are mainly from cricothyriod artery (51.9%) and superior laryngeal artery (25.0%) with an arterial trunk of 9.8 mm in length and 0.7 mm in diameter. The venous trunk is 17.4 mm in length and 1.1 mm in diameter. The muscle is innervated by the sub-broaches arising from hypoglossal nerve ansa, the trunk is 19.6 mm in length and 0.6 mm in diameter. CONCLUSION: It is possible that musclebone flap of hyoideumomohyoid to renovate vocal fold according to the study of the muscle morphology characteristic.

Female↗
PubMed1999

[Advances in affinity chromatography].

This review is mainly concerned with the recent advances in (i) mechanism of affinity chromatography; (ii) the use of new techniques such as combinational chemistry, molecular imprinting, de novo design, fusion expression in discovery of ligand; (iii) improvement of support and chromatographic system; (iv) application of affinity chromatography. The review includes 66 references.

Biomimetics↗
PubMed1999

[Effects of microwave acute irradiation on biomechanic properties of rabbit tissues].

The rabbit body was irradiated acutely by 2.45 GHz continuous microwave. After irradiation, the values of blood viscosity, blood viscoelasticity, platelet aggregation, erythrocyte fragility, erythrocyte deformation, erythrocyte aggregation, the compressive mechanic property and flexible property of bones were tested. The data of irradiated group and unirradiated group were compared. The results showed: after microwave irradiation, the rabbit blood viscosity and viscoelasticity decreased; the rabbit platelet aggregation rate decreased and the disaggregation rate increased; the erythrocyte fragility increased; the biomechanic properties of bones did not change considerably.

Animals↗
PubMed1999

[Study of methods for measuring spontaneous activation of neutrophils in vitro].

From the viewpoints of cellular morphology and enzymic histochemistry, we adopted the pseudopod method and NBT test for the measurement of spontaneous activation of neutrophils in vitro The time course curves of spontaneous activation of neutrophils from healthy donor were drawn. After comparing the pseudopod method with NBT test, we conclude that pseudopod method is more sensitive and reliable than NBT test and it can be used for real time observation; and that the curves of time course ascend from lower level to the highest level within 3 hours after the samples are collected, and then they descend gradually. The methodology of this study is available for use in future studies on the relationship between activation of neutrophils and many diseases.

Adult↗
PubMed1999

[Changes of F-actin in neutrophils under fluid shear stress].

Neutrophils are the main defender in the body, and their physiological characters are associated with functions. Because the environments of neutrophils maturation and storage are different from their function environment, they have to adapt thess changes. Filamentous actin (F-actin), as one of the important cytoskeleton components of neutrophils, has different quantity and distribution under different physiological conditions. Previous researches are all focused on static activation of neutrophils using various stimulants such as formyl-methionyl-leucyl-phenylalanine (f-MLP) and tumor necrosis factor(TNF). In our study, Low-Shear 30 and NXE-1 rheometers were used to provide steady or sinusoidaloscillatory fluid shear stress on separated neutrophils. Fluorescent agent Tritc-Phalloidin was added to label F-actin and the mean fluorescent intensity tested by flow cytometry was used as the indication of F-actin quantity and confocal laser scan microscope was used to detect the distribution of F-actin in neutrophils. We found that F-actin polymerization was significantly decreased under both steady and sinusoidal-oscillatory shear stress when the shear stress was below certain level. The density of the cortex F-actin near cell membrane in cells sheared became thinner than in that without shear stress. f-MLP and TNF both could increase actin polymerization in neutophils due to activation. When neutorphils were activated with f-MLP or TNF under shear stress, the quantity of F-actin in the cells was also decreased, but it was still higher than that in the cells absent of f-MLP or TNF. We concluded that neutrophils had different mechanical properties in different fluid environments. F-actin content and distribution would change according to the shear stress values to play their determinant role in neutrophils mechanical adaptation. The mechanism of actin polymerization in neutrophils for mechanical action is probably different from that for chemoattractants and cytokine activation.

Actins↗
PubMed1999

[Simulation on the hydrodynamics of a flow chamber system].

The distributions of the velocity and the shear stress of flow chamber are achieved by using the nondimensional technique and the method of Bessel function of imaginary argument according to Navier-Stokes' equations. When reduced to the representation of steady flows, the formulae obtained in this paper are consistent with Cao's theoretical formulae and their experimental results.

Computer Simulation↗
PubMed1999

[Effects of fluid shear stress on neutrophil surface expression of adhesion molecules].

Fluid shear is a physiological and functional environment for circulating neutrophils where various chemoattractants and cytokines have different effects on neutrophils, activating them or evoking inflammation. So far there have been abundant in vitro researches demonstrating that while neutrophils are activated, some adhesion molecules, which are expressed on the surface of neutrophils, are necessary to cell-to-cell adhesion, and the quantity or quality of these molecules will be changed. The above results were all obtained under static fluid which is quite different from physiological condition. Recently, we used Low-Shear 30 to provide steady or sinusoidal-oscillated fluid shear stress on separated neutrophils with or without f-MLP/TNF stimulation. FITC-anti CD18 monoclonal antibody and PE-anti CD62L monoclonal antibody were added to label CD18 and CD62L on neutrophils suface respectively. Flow cytometry was used to quantify surface expression and positive cell percentage of these two adhesion molecules. The results demonstrat that fluid shear stress increases the expression of CD18 significantly and decreases the CD62L positive cell percentage, but it does not influence the CD62L expression on the CD62L positive cells. The effects of the different patterns of fluid shear stress are not much different, f-MLP or TNF can slightly decrease the expression of CD18 and make CD62L shedding respectively. When one of the two activators and the fluid shear stress act together, the expression of the two adherent molecules can be added. This indicates that the mechanical and biochemical stiumlative action can produce different effects through different receptors and different signal transduction pathways. So the mechanical environment should be considered in the research of activation and adhesion of neutrophils.

Adult↗
PubMed1999

[Changes of biomechanical properties in goats at different times after ovariectomy].

This paper presents the changes of biomechanical properties in goats at different times after ovariectomy. 14 goats were randomly divided into three groups. These goats were ovariectomized and sacrificed at 180 days (n = 4), 360 days (n = 5) and 540 days (n = 5) after the operation. The right femur, tibia and metatarsus were taken out. The structure mechanical properties of femora were measured with the three-point bending method and those of metatarsus were measured with the compressing method. The material mechanical properties of flexure, compress and tensile strength in the compact bone specimens of femora and tibiae taken from broken ends were also measured. The results showed that the one-year group, compared with the half-year group, had all the bone geometric parameters decreased, but not statistically significant (P > 0.05); the elastic modulus of three-point bending of femora decreased by 23.27% and the others had no significant difference (P > 0.05); all the material parameters of flexurel, compress and tensile strength in compact bone specimens decreased, but only the ultimate strength of tibiae of flexure, compress and tensile strength decreased obviously (P < 0.05). The one and a half year group, compared with the one year group, had the bone density of femora and tibiae decreased, but not statistically significant (P > 0.05). All the bone geometric parameters of tibiae and the thickness of bone of femora increased (P < 0.05). The break load of three-point bending of femora increased (P < 0.05). Probably, it was related to the increase of the body weight in the one and a half year group. The elastic modulus and the ultimate strength decreased, but not statistically significant (P > 0.05). When compact bone specimens were used, the ultimate strength and elastic modulus of femora and tibiae in compress and the elastic module of tibiae in flexure decreased obviously (P < 0.05); and the others had no significant changes (P > 0.05). This study indicated that the degree of osteoporosis in ovariectomized goats increased at half a year, one year, and one and a half year postoperation, and hence suggested that the ovariectomized goat be a pretty useful big animal model of osteoporosis.

Animals↗
PubMed1999

[Effects of anticoagulants, temperature and sex on the spontaneous activation of neutrophils in vitro].

From the view of cellular morphology and enzymic histochemistry, we used the pseudopod method and NBT test to measure spontaneous activation of neutrophils in vitro. The effects of anticoagulant, temperature, and sex on the percentage of spontaneously activated neutrophils were studied. The results suggest that heparin is a better anticoagulant than EDTA because EDTA because EDTA inhibits neutrophil activation; that a higher percentage of activated neutrophils can be obtained when incubated at 37 degrees C, compared with the percentage at 25 degrees C, and at 37 degrees C the highest percentage appears an hour earlier; and that females show a higher percentage of spontaneously activated neutrophils than males, and females' highest percentage appears an hour earlier than males'. These are of referential value for further studies.

Adult↗