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Biomedical subjects

X Jiang

Publications and source records attributed to X Jiang.

At least 307 records · Page 17Linked to original sources
PubMed1997

Ca2+ or phorbol ester but not inflammatory stimuli elevate inducible nitric oxide synthase messenger ribonucleic acid and nitric oxide (NO) release in avian osteoclasts: autocrine NO mediates Ca2+-inhibited bone resorption.

Osteoclast bone resorption is essential for normal calcium homeostasis and is therefore tightly controlled by calciotropic hormones and local modulatory cytokines and factors. Among these is nitric oxide (NO), a multifunctional free radical that potently inhibits osteoclast bone resorption in vitro and in vivo. Previous findings led us to propose that NO might serve as an autocrine, as well as paracrine, regulator of osteoclast function. This premise was investigated using isolated bone-resorptive avian osteoclasts and focusing on the inducible isoform of NO synthase (iNOS) responsible for inflammatory stimulated high-level NO synthesis in other cells. Avian osteoclasts expressed both iNOS messenger RNA (mRNA) and protein. However, inflammatory cytokines that induce iNOS mRNA, protein, and NO in other cells did not do so in avian osteoclasts, consistent with the known role of inflammatory stimuli in promoting osteoclast resorption and localized bone loss. In searching for potential modulators of osteoclast iNOS, protein kinase C activation [by phorbol 12-myristate 13-acetate (PMA)] and intracellular Ca2+ rises (A23187) were each found to elevate osteoclast iNOS mRNA and protein levels, while increasing NO release and reducing osteoclast bone resorption. The iNOS selective inhibitor aminoguanidine suppressed stimulated osteoclast NO production elicited by either signal, but reversed only the resorption inhibition due to raised Ca2+. Thus, whereas additional inhibitory signals are presumably coproduced in osteoclasts treated with PMA, osteoclast iNOS-derived NO may act as an autocrine signal to mediate Ca2+-inhibited bone resorption. These findings document for the first time an iNOS whose mRNA levels are regulated by Ca2+ or PMA, but not inflammatory stimuli, and the autocrine production of NO as a Ca2+ sensing signal to suppress osteoclast bone resorption. The unusual regulation of osteoclast iNOS makes it a potentially attractive target for designing novel therapeutic agents to alleviate excessive bone loss.

Animals↗
PubMed1997

Identification of hydrogen peroxide oxidation sites of alpha A- and alpha B-crystallins.

The alpha-crystallins are the most abundant structural proteins of the lens and, because of their chaperone activity, contribute to the solubility of the other crystallins. With aging, the lens crystallins undergo a variety of modifications which correlate with a loss of solubility and the development of cataract. A recent study demonstrating that alpha-crystallins exposed in vitro to FeCl3 and H2O2 exhibit decreased chaperone activity, implicates metal catalyzed oxidations of alpha-crystallins in this loss of solubility. The present study has determined that alpha-crystallins incubated with FeCl3 and H2O2 are modified by the nearly complete oxidation of all methionine residues to methionine sulfoxide, with no other detectable reaction products. The modifications were identified from the molecular weights of peptides formed by enzymatic digestion of the alpha-crystallins and located by tandem mass spectrometric analysis of the fragmentation pattern of the mass spectra of the fragments from peptides with oxidized methionine is loss of 64 Da, which corresponds to loss of CH3SOH from the methionine sulfoxide. These fragments are useful in identifying peptides that include oxidized methionine residues.

Amino Acid Sequence↗
PubMed1997

[Clinical application of highly selected embolotherapy via external carotid artery in craniofacial diseases].

Forty-three cases of hypervascularized tumors and vascular lesions supplied by external carotid artery were treated by endovascular embolization. The results showed that hypervascularized tumor's bleeding markedly reduced and its volume diminished during operation; vascular lesions were cured or improved after embolization. The choice of embolic materials and technical essentials were discussed.

Adolescent↗
PubMed1997

[The role of opioid receptors of arcuate nucleus in cytokine-induced hyperthermia].

The present study is to define the role played by the opioid receptors of ARH in the regulation of body temperature. 1 microliter of IL-1 beta (as pyrogen) was injected into the ARH of male Sprague-Dawley rat with an automatic micromanipulator to induce hyperthermia. 30 minutes prior to the injection of pyrogen, the experimental groups were pre-treated with general opioid receptor antagonist naloxone (Nal), selective mu, delta, kappa receptor antagonists CTAP, NTI, nor-BNI respectively. Controls were pre-treated with saline. The results showed that IL-1 beta-induced hyperthermia was blocked by Nal and CTAP, suggesting the involvement of, or mediation by, ARH opioid receptors (mainly the mu type) in IL-1 beta-induced hyperthermia. The blockade by delta and kappa antagonists was not remarkable. Thus their participation in this process is less likely. The similarity between the roles of opioid receptors of ARH and POAH in IL-1 beta-induced hyperthermia strongly supports the view that ARH may be an important component of the thermoregulatory center.

Animals↗
PubMed1997

[The application of corticosteroid following photorefractive keratectomy].

OBJECTIVE: The application methods of corticosteroid following excimer laser photorefractive keratectomy (PRK) were compared. METHODS: PRK was performed on 600 myopic eyes with Nidek-EC 5000 PRK System, and then randomly they were divided into group A (228 eyes) and B (372 eyes). Different methods of application of corticosteroid were performed in the two groups. The follow-up period was 6 months. RESULTS: After 6 months of follow-up, the rate of uncorrected visual acuity > or = 0.8 or > or = 1.0 was 97.9%, 93.2% in group A and 98.6%, 93.5% in group B, respectively. Transient ocular hypertension occurred in 2.2% in group A and 2.7% in group B, but the difference was statistically not significant (P > 0.05), the rate of haze greater than grade 1 was 18.4% in group A and 5.4% in group B, with statistically significant difference (P < 0.05). CONCLUSION: After PRK, the appropriate application of corticosteriod can effectively reduce the rate of haze formation and regression towards myopia caused by haze. Powerful corticosteroid used at postoperative early stage and its low concentration at later stage can reduce the incidence of corticosteroid ocular hypertension.

Administration, Topical↗
PubMed1997

[Study on the effect of continuous administration of IL-1ra in BXSB mice].

OBJECTIVE: To explore the consequences of IL-1 blocking in BXSB mice which is an experimental model for human SLE. METHODS: rh IL-1ra was expressed in E. coli and injected in BXSB mice. 13 of 4.5 month-age male BXSB mice were divided into two groups, one group was injected rh IL-1ra 10 times (twice a week) at dose of 400 micrograms per mouse each time, another group was injected PBS at the same time as control. We monitored serum ANA and proteinuria weekly, and detected IgG, C3 deposition and IL-6 expression in kidneys at 40th day. RESULTS: The results showed that the increased level of serum ANA and proteinuria in treatment group were not higher than in control group, the IgG, C3 deposition and IL-6 expression in kidneys and IL-6 activity in serum of the treaed group were lower than the control group, whereas no difference of GPT level in the two groups. CONCLUSION: IL-1 might play a pathogenic role in BXSB mice. Blocking or reducing IL-1 secretion would be of beneficial to the treatment of SLE.

Animals↗
PubMed1997

[Down-regulation effect of HIM82 on respiratory burst of neutrophil].

OBJECTIVE: The early control of respiratory burst of Neutrophil (PMN) was studied by using McAb HIM82. METHODS: PMNs were isolated from healthy volunteers. Superoxide anion, Hydrogen peroxide were measured in the presence of HIM82 FMLP. Sustance P and the NEP activities was measured in the presence of HIM82 alone. RESULTS: The amount of O2.- and H2O2 produced in experimental group (by combining with HIM82) are (44.00 +/- 8.9)% (n = 8, P < 0.01) and (65.16 +/- 15.41)% (n = 8, P < 0.01) of control group respectively. The activity of NEP inactivated by PMA (without HIM82) is (43.29 +/- 9.41)% (n = 8, P < 0.05) and the activity is (66.48 +/- 15.53)% (n = 8, P < 0.05) in PMA-inactivated group with HIM82. CONCLUSIONS: The result mentioned above showed that the HIM82 monoclonal antibody exerts obvious down regulation on respiration burst induced by PMA and antagniation on inactivity of NEP. We under stand that this McAb has important regulation effect on function of PMN, it shows that the specific combination with corresponding antigen on membrane is essential for function of PMN especially for mechanism of respiratory burst of activated PMN.

Antibodies, Monoclonal↗
PubMed1997

[Gama hydroxybutyrate sodium (gama-OH)-diazepam combined anaesthesia for cleft palate repair in children below 3 years old].

UNLABELLED: To investigate the effect of Gama-OH-Diazepam combined anaesthesia for cleft palate repair in children below 3 years old. METHODS: Heart rates were measured in 120 children at induction, at 5 minutes after endotrocheal intubation, at finishing of operation, and at 5 minutes after extubation. In addition, changes of SpO2 was randomly detected in 10 children. RESULTS: Heart rate decreased after intubation, increased when operation was completed and decreased again after extubation. SpO2 of all stages were in the normal range. CONCLUSIONS: This method of anaesthesia is suitable for cleft palate repair in children below 3 years old, with the advantages of little effect on the children's circulatory and respiratory systems, and being easy to perform and control.

Anesthesia, Intravenous↗
PubMed1997

[The correlation between tumor angiogenesis and lymph node metastasis in primary breast carcinoma].

To study the relationship between tumor angiogenesis and lymph node metastasis in primary breast carcinoma. Agiogenesis was assessed by the microvessel density (MVD) and expression of vascular endothelial growth factor (VEGF) using immunohistochemical staining. Paraffin-embedded specimens from 70 patients with primary breast cancer who had undergone radical mastectomy from 1984 to 1985 were studied. Thirty-one patients had histologically proven positive axillary lymph node (N+). The axillary node negative (N-) group was composed of thirty-nine patients. Microvessels per 200x (as MVD) and VEGF positively stained cancer cells per 400x were counted with light microscope. MVD and VEGF expression were higher in tumors with N+ showed than those with N-, MVD and VEGF expression were higher in N+ than in N-. MVD and the expression of VEGF are highly correlated with metastasis in primary breast cancer, which may serve as a parameter for determining tumor biological, metastatic potential and prognosis.

Adult↗
PubMed1997

[The value of the ratio of--SP/AP in diagnosing Ménière's disease].

To further explore the diagnostic value of the ratio of--SP/AP (> 0.4) in Ménière's disease, the EcochG results from 70 (76 ears) cases with Ménière's disease were compared to that of 49 cases with sudden hearing loss(SHL), noise induced hearing loss(NIHL), ototoxic hearing loss, and 20 normal hearing person. The effects of different stimulus intensities and the degree of hearing loss on the detectable rate of--SP, the ratio of--SP/AP and its feature in the above mentioned disease were analysed. The results indicated: 1. The mean ratio of--SP/AP was 0.39 +/- 0.02 in normal person on 75 dB nHL stimulus level, while it was larger than 0.45 in SHL and NIHL on 75 dB and 65 nHL stimulus level respectively. 2. There was a rapid descending trend of the ratio of--SP/AP with stimulus level from 65 to 55 dB nHL in all ears except Ménière's cases, which was correlated with stimulus level as well as the degree of hearing loss. 3. The mean ratio of--SP/AP presented linear increase when stimulus level was < or = 75 dB nHL, and when stimulus level was > 75 dB nHL, the mean ratio of--SP/AP no longer presented linear increase and could even decrease, it suggested stimulus level on 75 dB nHL could be used as the diagnostic stimulus level. 4. If the degree of hearing loss exceeded 80 dB HL, the ratio of--SP/AP > 0.4 had no practical significance in diagnosis.

Adolescent↗
PubMed1997

[The application of lossless compression algorithm for ECG data in HOLTER].

Recently, HOLTER product is developing to long time recording. In order to decrease the cost, compression of ECG data is needed. It is done first by some kind of DPCM to decrease the range of the data Value, then by using suitable arithmetic of HUFFMAN coding's and Arithmetic coding's. All the methods can be realized in microprocessor and get compression ratio of 2-4.

Algorithms↗
PubMed1997

[The effect of cryotreat on the size of the medium and high melting-point castable alloys].

Castable alloys are widely used in prosthodontics. The properties of alloys can be improved by cryotreat. This method may cause a size alteration of materials. This study revealed the effects of different cooling rates on the size of the castable alloys. The results showed: 1. The rapid cooling rate caused significant deformation of the alloys. 2. The 3 degrees C/min rate and the 1 degree C/min rate did not cause any significant deformation of the alloys. 3. The 3 degrees C/min rate and the 1 degree C/min rate did not show any difference in their deformation causing ability. 4. The rapid cooling rate and the slow cooling rate (3 degrees C/min and 1 degree C/min) showed significant difference in their deformation causing ability. These results suggested that 3 degrees C/min was recommendable as a cooling rate of the cryotreat of the medium and high melting-point castable alloys.

Cold Temperature↗
PubMed1997

[The effect of cryotreat on the mechanical properties of the medium and high melting-point castable alloys].

Two mechanical properties that are closely related to the clinical practice, i.e. the surrendering toughness and the hardness, of the medium and high melting-point castable alloys, were tested before and after the cryotreat. The results showed: 1. Cryotreat significantly increased the surrendering toughness of the medium and high melting-point castable alloys (40.00%); 2. Cryotreat significantly increased the surrendering toughness of the medium and high melting-point castable alloys (25.45%); 3. Cryotreat significantly increased the surrendering modulus of the high melting-point castable alloys (25.77%); 4. Cryotreat significantly increased the hardness of the medium melting-point alloys(24.40%); 5. Cryotreat significantly increased the hardness of the medium melting-point alloys (7.77%). These results suggest that cryotreat is an effective procedure in enhancing the toughness and hardness of the medium and high melting-point castable alloys.

Cold Temperature↗
PubMed1997

[Pharmacological studies of luohanguo yanhou tablet].

Luohanguo Yanhou Tablet possesses the action of cotton ball granuloma of mice and the auricular edema induced by xylol, and also inhibiting the swelling of rat hind paw induced by carrageenin. The tests of mice writhing induced by acetic acid showed that the preparation had obvious analgesic action. It also possesses the obvious bacteriostatic action in vitro on five kinds of strains.

Analgesics↗
PubMed1997

[Biological characteristics of residual leukemic cells and their drug-resistant regrowth].

OBJECTIVE: To elucidate the mechanisms of residual leukemia and its drug-resistant regrowth. METHODS: Bone marrow cells from transplantable mouse leukemia models L615 and L7811 were cultivated in long-term culture system respectively. Daunorubicin (DNR) was added to the systems to mimick in vivo chemotherapy. RESULTS: Residual leukemic cells on stromal layers escaped DNR killing. They derived from the adherent leukemic cell population, which was heterogeneous with many undifferentiated and dormant cells. They were drug-resistant and expressed bcl-2 gene. CONCLUSION: Bone marrow stromal layer was the vital microenvironment for the residual leukemic cells to survive and regrow, and might increase the drug-resistance by up-regulating bcl-2 gene expression.

Animals↗
PubMed1997

[Comparative study of two fusion retinoic acid receptor alpha in acute promyelocytic leukemia].

OBJECTIVE: To make a comparison of biological properties between PML-RARalpha and PLZF-RARalpha fusion proteins. METHODS: Receptor radioligand binding assay, receptor DNA binding assay and immunofluorescence methods were used. RESULTS AND CONCLUSION: PML-RARalpha and PLZF-RARalpha had similar ligand-binding affinities. Both could bind in vitro to retinoic acid response elements (RAREs) forming homodimers and to retinoic acid X receptor. However ,they differed in the relative binding affinities to different RAREs,the behavior of forming complex with RXR and the subcellular localization. More importantly, PML-RARalpha and PLZF-RARalpha could block different regulatory pathways mediated by PML or PLZF, through heterocomplex formation with wild-type PML or PLZF. The differences between PML-RARalpha and PLZF-RARalpha may in part explain the apparent resistance of APL with t(11;17) to differentiating effect of all-trans retinoic acid (ATRA).

DNA↗
PubMed1997

[Determination of plasma drug concentration and bioavailability of indomethacin controlled release capsule by high performance liquid chromatography].

A simple, rapid, sensitive and accurate reversed-phase high performance liquid chromatographic (RP-HPLC) method for the determination of indomethacin in plasma is established. To 1 mL of plasma were added 200 microL of amobarbitone solution (internal standard; 1 g/L), 100 microL of phosphate buffer solution (pH 7.0), 100-150 mg of sodium chloride and 2.5 mL of ethyl acetate. The mixture was vortex-mixed for 10 min and centrifuged at 3000 r/min for 5 min. The organic layer was evaporated to dryness at 50 degrees C on water-bath and the residue was dissolved in methanol (100 microL). A 20 microL portion of the resulting solution was analysed by HPLC on a column (25 cm x 4.6 mm) of micro-Bondapak C18 (10 microm) with 76% methanol in 0.035 mol/L phosphoric acid (pH 5.5) aq-solution as mobile phase (1 mL/min) and UV detection at 260 nm. The column temperature was 30 degrees C. Within the range of 0.125-50 mg/L of indomethacin there was a good linearity (r = 0.9996). The mean recovery of indomethacin was 100.4%. The detectable limit was 62.5 microg/L (S/N = 3:1). The within day and day-to-day RSD were less than 5% at three drug levels. This method has been used to determine plasma drug concentration and bioavailability of indomethacin controlled release capsule for healthy volunteers.

Anti-Inflammatory Agents, Non-Steroidal↗