Biomedical subjects

L Xie

Publications and source records attributed to L Xie.

At least 91 records · Page 5Linked to original sources

PubMed1999

[Analysis of the treatment of 82 patients with inhalation injury].

OBJECTIVE: To learn the experiences and improve the treatment of inhalation injury. METHODS: Causes of death and treatment effects were analyzed in a group of 82 patients admitted from January 1994 to April 1998. RESULTS: Among the 82 patients, 33 patients were cured, 11 patients were improved and 38 patients died. Among the 38 cases of death, 24 patients died directly of inhalation injury and 14 patients died of other complications. CONCLUSION: The major causes of death of the patients with inhalation injury are acute intoxication, asphyxia, and ARDS(acute respiratory distress syndrome). For the treatment, tracheostomy should be carried out the earlier the better. Moistening of the airway and lavage may be effective in preventing lung infection, facilitating the ejection of phlegm and necrotic mucosa. The amount of fluid infusion should appropriately be increased and this will not lead to lung edema. Administration of corticol hormone in the early stage for a short period will also result in positive effects.

Administration, Inhalation↗

PubMed1999

DNA vaccine pCD-Sj32 and its efficacy of protective immunity against infection of Schistosoma japonicum.

OBJECTIVE: To study protective immunity afforded by murine immunization with DNA vaccine of Schistosoma japonicum (S. japonicum) as measured by reduction in worm burden and host antibody, cytokines. METHODS: DNA vaccine pCD-Sj32 was constructed, identified and expressed. pCD-Sj32 could induce substantial protective immunity against infection of S. japonicum in BALB/c mice. The best efficacy can be produced with one injection of 100 micrograms DNA into the quadriceps muscle, combined with challenge for 8 weeks after immunization. T lymphocyte subsets of CD8+, IL-2. TNF and IFN-gamma of experimental animal could play important roles in regulating immune functions of schistosomiasis. RESULTS: High titre of specific antibody IgG could be induced by vaccinated with pCD-Sj32, and antibody can mediate macrophage to produce ADCC effects in vitro. CONCLUSION: pCD-Sj32 may represent a new approach to developing subunit vaccine.

Animals↗

PubMed1999

The diagnostic criteria for classic parasystole.

OBJECTIVE: To establish a diagnostic criteria of parasystole with high sensitivity and high specificity. METHODS: After excluded from nonparasystole and each variant parasystoles, based on the electrocardiographic data obtained from 61 patients with classic parasystole, we selected the quantitative indices which could reflect the features of ectopic focus with complete entrance block as the diagnostic criteria for parasystole. RESULTS: The common features of the electrocardiograms of this group were: 1) Take the earliest recorded eight interectopic intervals in which at least four intervals containing sinus beats or other beats having activated to the area within the ectopic focus. When in case of deficiency, it will fill up a vacancy in order. The ratios of the shortest coupling interval to the shortest ectopic cycle length (ECL) were all less than 80%; 2) The coefficients of variation of the eight ECLs were all less than 6%; 3) The maximal differences of coupling intervals were all equal to or more than 0.11 second. CONCLUSION: Three quantitative indices as necessary conditions have been used as diagnostic criteria for parasystole with high sensitivity and high specificity.

Electrocardiography↗

PubMed1999

[Clinical diagnosis of fungal keratitis by confocal microscopy].

OBJECTIVE: To illustrate the value of confocal microscope in the diagnosis of fungal keratitis. METHODS: In vivo confocal microscopy was performed on 43 patients of suspected fungal keratitis. The results were compared to that of smears and biopsies. RESULTS: Fungal filaments were imaged in 31 of 43 patients' corneas. Fungal keratitis was diagnosed in 32 patients based on clinical signs and all the methods of examinations. The positive rate of confocal microscopy is 96.9%. CONCLUSION: Confocal microscopy can be a rapid, effective and noninvasive imaging technique, and it is helpful in the diagnosis, treatment and study of fungal keratitis.

Adolescent↗

PubMed1999

[Measurement of retinal nerve fiber layer thickness of normal eyes with nerve fiber analyzer].

OBJECTIVE: To study the retinal nerve fiber layer thickness (RNFLT) of normal eye and the correlation with age. METHODS: RNFLT of 198 cases of normal eyes were examined by using nerve fiber analyzer (NFA). RESULTS: There were significant inverse linear correlation between the RNFLT and age (r = -0.46, P < 0.01). In the analysis by the quadrant, the RNFLT was correlated with age in the superior and inferior quadrant. The mean ratio of superior and inferior quadrant thickness (S/I) was 1.041. CONCLUSION: NFA seems to be an useful tool to measure the RNFLT quantitatively. The RNFLT of normal eye is found to be decreased with age.

Adolescent↗

PubMed1999

[Ocular pharmacokinetics of pilocarpine micron emulsion in rabbits].

OBJECTIVE: To compare the pharmacokinetics of pilocarpine micron emulsion with generic pilocarpine solution in the aqueous humor. METHODS: 60 albino rabbits were used and were divided into 20 groups, each consisting of 3 animals. 10 groups received 2% generic pilocarpine 50 microl as controls; 10 groups received 50 microl of 2% pilocarpine micron emulsion in the conjunctival sac. The aqueous humor was withdrawn at 5, 10, 30, 40, 60, 90, 120, 180, 240 and 360 min. after instillation. The drug was extracted from aqueous humor with dichloromethane. The drug was analyzed by reversed phase high pressure liquid chromatography (HPLC). RESULTS: Pilocarpine micron emulsion therapy gave higher aqueous humor concentration of the drug than drops at all time periods tested except 5 min. time point (P = 0.0003 - 0.042). The area under curve of micron emulsion was 3 times as much as that of drops. There was a two-fold increase in ocular bioavailability of pilocarpine due to the therapy with micron emulsion. Measurable amounts of drug following 2% micron emulsion were still observed at 360 min. while drug levels at 180 min. following 2% drop therapy were nil. CONCLUSION: Our study results demonstrated significantly increase in ocular bioavailability of pilocarpine due to the therapy with micron emulsion. Our finding indicates that a novel topical preparation of pilocarpine incorporated in micron emulsion might serve as a long acting antiglaucoma agent, and less frequent applications are necessary with it than with conventional drops.

Animals↗

PubMed1999

[Animal model for Alzheimer's disease based on the blockade of neuronal nicotinic acetylcholine receptors].

The intrahippocampus injection of Kappa-bungarotoxin (K-BGT) caused a significant impairment in learning and memory abilities of mice, in order to create an animal model for Alzheimer's disease. The spatial learning and memory abilities in the Morris water maze in the model group (K-BGT impaired mice) decreased significantly compared with control group. K-BGT impaired mice also showed learning and memory reduction with shorter latency and more mistakes in step-through test.

Alzheimer Disease↗

PubMed1998

Anti-AIDS agents. 33. Synthesis and anti-HIV activity of mono-methyl substituted 3',4'-di-O-(-)-camphanoyl-(+)-cis-khellactone (DCK) analogues.

Four isomeric methyl substituted DCK analogues (2-5) were asymmetrically synthesized from different starting materials. 3-Methyl, 4-methyl, and 5-methyl-3',4'-di-O-(-)-camphanoyl-(+)-cis-khellactone (2-4) all were extremely potent against HIV-1 replication in H9 lymphocyte cells with EC50 and therapeutic index values of < 4.23 x 10(-7) microM and > 3.72 x 10(8), respectively, which are much better than those of DCK and AZT in this assay.

Anti-HIV Agents↗

PubMed1998

GTP cyclohydrolase I inhibition by the prototypic inhibitor 2, 4-diamino-6-hydroxypyrimidine. Mechanisms and unanticipated role of GTP cyclohydrolase I feedback regulatory protein.

2,4-Diamino-6-hydroxypyrimidine (DAHP) is considered to be a selective and direct-acting inhibitor of GTP cyclohydrolase I (GTPCH), the first and rate-limiting enzyme in the pathway for synthesis of tetrahydrobiopterin (BH4). Accordingly, DAHP has been widely employed to distinguish whether de novo BH4 synthesis is required in a given biological system. Although it has been assumed that DAHP inhibits GTPCH by direct competition with substrate GTP, this has never been formally demonstrated. In view of apparent structural homology between DAHP and BH4, we questioned whether DAHP may mimic BH4 in its inhibition of GTPCH by an indirect mechanism, involving interaction with a recently cloned 9.5-kDa protein termed GTPCH Feedback Regulatory Protein (GFRP). We show by reverse transcription-polymerase chain reaction that GFRP mRNA is constitutively expressed in rat aortic smooth muscle cells and further induced by treatment with immunostimulants. Moreover, functional GFRP is expressed and immunostimulant-induced BH4 accumulates in sufficient quantity to trigger feedback inhibition of GTPCH. Studies with DAHP reveal that GFRP is also essential to achieve potent inhibition of GTPCH. Indeed, DAHP inhibits GTPCH by dual mechanisms. At a relatively low concentration, DAHP emulates BH4 and engages the GFRP-dependent feedback inhibitory system; at higher concentrations, DAHP competes directly for binding with GTP substrate. This knowledge predicts that DAHP would preferably target GTPCH in tissues with abundant GFRP.

Animals↗

PubMed1998

Binding of SH1-SH2-modified myosin subfragment-1 to actin.

Myosin subfragment-1 (S1) was labeled with NPM in the presence of ATP or with pPDM in the presence of ADP at 0 degreesC, conditions which favor linking of maleimide groups to both Cys-707 (SH1) and Cys-697 (SH2). Unmodified S1 was removed by sedimentation with a small amount of F-actin, and the modified protein in the supernatant thoroughly dialyzed. The myosin high-salt EDTA and calcium ATPase activities of the isolated modified S1 were close to zero, suggesting nearly complete modification of SH1 and SH2. The binding of control and these modified myosins to actin was measured at 100 mM ionic strength using a co-sedimentation assay. In the presence of high MgATP concentration, control and NPM- and pPDM-reacted S1 all bind weakly to actin, with binding constants K3 of 4.9, 2.2, and 1.9 x 10(4) M-1, respectively. In the absence of MgATP, the binding constant K2 of pPDM-reacted S1 remains weak, 4.6 x 10(4) M-1,while that of NPM-reacted and control S1 becomes strong, 4.7 and 31 x 10(6) M-1, respectively. The binding constant for ATP to acto-NPM-reacted-S1 is approximately 2 x 10(4) M-1. Our data suggest that the binding of NPM-S1 to F-actin, in contrast to that of pPDM-S1, is ATP sensitive and can be quite strong at very low ATP concentration. They also suggest that while simple alkylation of SH1 and SH2 may be sufficient to inhibit myosin's ability to hydrolyze ATP, actual covalent linkage of SH1 and SH2 may be necessary to inhibit the weakly to strongly binding conformational change.

Actins↗

PubMed1998

Role of intracellular calcium ([Ca2+]i) and tyrosine phosphorylation in adhesion of cultured vascular smooth muscle cells to fibrinogen.

OBJECTIVE: Fibrinogen is an independent risk factor for cardiovascular disease. This study has investigated the role of intracellular Ca2+ ([Ca2+]i) and tyrosine phosphorylation in the attachment of human and rat-derived cultured vascular smooth muscle cells to fibrinogen. METHODS: Cells were cultured from human saphenous vein segments (HVSMC) and from an established rat aortic cell line (A7r5). [Ca2+]i was measured using fura-2 and adhesion was studied using pre-coated 96 well polystyrene plates. RESULTS: Fibrinogen increased [Ca2+]i in both cell types. In A7r5 cells fibrinogen-induced increases in [Ca2+]i were partially inhibited by a peptide containing the amino acid sequence Arg-Gly-Asp (RGD) which interferes with binding to integrins. In contrast RGD increased [Ca2+]i in HVSMC, but did not inhibit responses to fibrinogen. Ni2+, an inorganic calcium channel blocker largely abolished the rise in [Ca2+]i, but blockers of voltage-operated calcium channels failed to affect [Ca2+]i responses to fibrinogen in either cell type. Genistein, an inhibitor of tyrosine kinase inhibited fibrinogen-induced rises in [Ca2+]i, while daidzein, an inactive analogue, was without effect. Adhesion of cells to fibrinogen was concentration- and time-dependent. Cell adhesion to fibrinogen was partially inhibited by RGD peptide in both cell types. Adhesion of cell to fibrinogen was inhibited by chelation of [Ca2+]i with BAPTA-AM, inhibition of Ca2+ entry by Ni2+, and inhibition of tyrosine kinases by genistein, but heparin had no effect on adhesion. CONCLUSIONS: Vascular smooth muscle cells attach to fibrinogen in part through RGD-type interactions. Activation of tyrosine kinase(s) and a subsequent rise in [Ca2+]i appear to be important signals mediating the response to fibrinogen.

Animals↗

PubMed1998

Purification and activity study of the A- and B-chains of cinnamomin, a type II ribosome-inactivating protein.

The strong hydrophobic interaction between the A- and B-chains of cinnamomin, a type II ribosome-inactivating protein, makes it difficult to separate A- and B-chains after the disulfide bond is broken. We failed to separate the A-chain from B-chain of cinnamomin using methods under usual conditions. A convenient method for purification of the A- and B-chains of cinnamomin on a large scale has been developed. We chose urea to weaken the non-covalent interaction between the A- and B-chains. In the presence of 4M urea, the A- and B-chains of the reduced cinnamomin are separated effectively by DEAE-cellulose chromatography. The purified A-chain still displays the RNA N-glycosidase activity and the B-chain loses the lectin activity. After refolding in vitro in the presence of lactose, the B-chain is renatured and the active B-chain with lectin activity can be further purified by Sepharose 4B affinity chromatography. From 80 mg of cinnamomin, 10 mg of A-chain (25%) and 38 mg of the B-chain (95%) were obtained. In addition, the intrinsic fluorescence spectra of the A- and B-chains were employed to study the structural changes in the active and the non-active forms of cinnamomin A- and B-chains.

Algal Proteins↗

PubMed1998

[The influence of immediate postpartum insertion of GyneFix PP-intrauterine devices on puerperal period].

OBJECTIVE: To investigate the effects of immediate postpartum insertion of GyneFix PP-intrauterine devices (IUD) on postpartum hemorrhage, bloody lochia and postpartum endometritis. METHODS: 126 women had GyneFix PP-IUD inserted immediately postpartum (IUD group) and another 118 cases with no IUD insertion were served as control. Blood loss during delivery, 2 and 24 hours after delivery were determined, the time of bloody lochial lasted and the incidence of postpartum endomeritis were recorded. RESULTS: There were no significant differences in the blood loss during and after delivery, and the incidence of endometritis between the 2 groups, but the bloody lochia was lasted significantly longer in the IUD group (P < 0.05). CONCLUSION: This results suggested that the immediate postpartum insertion of the GyneFix PP-IUD is a safe and good postpartum contraceptive method, and the cause of prolonging bloody lochia awaits for further study.

Adult↗

PubMed1998

[The experimental and clinical study of heliox in treating bronchial asthma].

OBJECTIVE: To evaluate the effects of breathing helium-oxygen(heliox: 79% He-21% O2) on bronchial asthma by way of experimental and clinical observations. METHOD: Six mongrel dogs were randomly inspired air or heliox after dripping 2% methacholine in its' tracheas controlled by 900C ventilator. During the experimental course, respiratory mechanical limits, hemodynamic index and blood gas values were observed. Eight asthmatic patients inspired heliox with assisted respirator of recycle-used helium, and the data of pulmonary function tests, arterial blood gas values of patients were recorded. RESULTS: The results demonstrated that heliox could reduce airway resistance, airway pressure and work of breathing, improve lung effective compliance, but had no effects on pulmonary circulation and systemic circulation. Heliox could ameliorate oxygen diffusion and CO2 eliminating, but the duration was very short after stopping breathing heliox. The assisted respirator of recycle-used helium could save helium distinctively, and the clinical application demonstrated that the instrument may be useful for pulmonary obstructive diseases. CONCLUSION: Heliox can reduce airway pressure, ameliorate oxygen diffusion and CO2 eliminating, so breathing heliox might be one of effective ways for asthmatic patients.

Adult↗

PubMed1998

[Changes of bone cytokines and compensating regulation in tail suspended rats].

The aim of the study was to determine the relationship between the changes in bone metabolism and insulin-like growth factor--I(IGF-I) as well as epidermal growth factor (EGF). 10 Male S.D. rats were tail-suspended for 28 d with another 10 free active rats as control. The results showed that mineral content increased significantly, osteocalcin and albumin content had no significant change, but IGF-I and EGF content increased significantly in L3 in the suspended rats. The results suggest that although there are no change in osteocalcin and albumin content, the phenomenon of bone mineral loss still exists in the suspended rats. The increase in IGF-I and EGF content may be one of the compensation responses of the bone in the suspended rats.

Animals↗

PubMed1998

[A preliminary observation on nuclear changes of human corneal endothelial cells in different kinds of corneal diseases].

OBJECTIVE: To investigate the influence of different kinds of corneal diseases on corneal endothelial cells. METHODS: The endothelial cells of 91 corneal buttons obtained at the time of penetrating keratoplasty (PKP) were stained by 1% alizarin red and 0.25% trypan blue and observed under biomicroscope. RESULTS: Binuclear and polynuclear endothelial cells were found in every buttons. CONCLUSION: Under special conditions, the human corneal endothelial cells possibly have stronger ability of mitosis and compensation.

Adolescent↗

PubMed1998

[Congenital cataract extraction with intraocular lens implantation in children].

OBJECTIVE: To evaluate the results of cataract extraction with intraocular lens (IOL) implantation in children. METHODS: Cataract extracapsular extraction with anterior vitrectomy and IOL implantation was performed on 104 eyes of 64 children with congenital cataract aged 1.5 - 14 years old. The visual acuity and possible complications were followed up for a mean period of 22 months. RESULTS: After operation 86.4% patients were relieved from blindness, 62.7% obtained corrected vision >or= 0.3, binocular vision and stereopsis were restored in 41.8% and 30.6% respectively. In 3 eyes secondary cataract developed and in 5 eyes slight iris capture occurred. CONCLUSIONS: Cataract extraction with anterior vitrectomy and IOL implantation is effective in pediatric cataract treatment. Most patients get remarkable improvement in visual acuity and visual function with minimal complications after surgery. The influence factors on the postoperative visual function need further study.

Adolescent↗

PubMed1998

[Treatment of intraocular fibrinous membrane by anterior chamber injection of tissue plasminogen activator after IOL implantation].

OBJECTIVE: To investigate the method of treatment of intraocular fibrinous membrane by tissue plasminogen activator (t-PA) after intraocular lens (IOL) implantation and evaluate its clinical results. METHODS: 58 eyes of 43 patients after cataract surgery were divided into three groups, and received t-PA anterior chamber (AC) injection or combined with YAG laser therapy at different times after the operation. Group 1 included 26 eyes which received 4 microg t-PA AC injection at the end of operation. In group 2, 22 eyes whose fibrinous membrane was formed 5 - 7 days after the operation were injected with 4 microg t-PA at that time. In group 3, 10 eyes with thicker membrane were given YAG laser treatment at postoperative 5 - 9 days and then 4 microg t-PA was injected into the AC. RESULTS: In group 1, hyphema occurred in 4 eyes, in 8 eyes at the pupillary region the fibrinous membrane was formed which was completely lysed after t-PA AC injection at postoperative 3 - 5 days. In group 2, the membrane was lysed within 24 hours in 20 of 22 eyes and no hyphema was found. In group 3, the membrane was lysed within 4 - 24 hours after t-PA injection in all cases, and no hyphema occurred. CONCLUSION: It is very effective to treat fibrinous membrane formation after IOL implantation by t-PA AC injection at postoperative 1 week when the AC inflammation is well controlled. The combined use of YAG laser with t-PA AC injection is much more effective for the treatment of such a membrane.

Adolescent↗