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Biomedical subjects

H Liu

Publications and source records attributed to H Liu.

At least 865 records · Page 48Linked to original sources
PubMed1997

[Design of CA-1680 biochemical analyzer].

The paper provides the design idea structure of key parts software and hardware of microprocessor of CA-1680 Biochemical Analyzer. The instrument uses the specific flow cell high properties photodiode and programmable amplifier. The 16 bit programmable A/D conversion is completed with V/F convertor and programmable counter. Logarithm conversion is completed with software. On Using these methods, the instrument has not only simpler circuit, better reliability, but also the characteristics of accuracy, precision and widely linearity.

Biochemistry↗
PubMed1997

The preliminary report of epikeratophakia in the treatment of pediatric aphakia after traumatic cataract extraction.

PURPOSE: To study the role of epikeratophakia in treating pediatric unilateral aphakia after traumatic cataract extraction. METHODS: We performed epikeratophakia in 43 children to treat aphakia after traumatic cataract extraction, using the corneal lenses made by ourselves. The rehabilitation of the the postoperative vision and the prevention of amblyopia were observed with a mean follow-up period of 20 months. RESULTS: All the lenses remained transparent. Postoperatively, 31 cases (72.1%) achieved uncorrected visual acuities (V.A) over 0.2, 32 cases (74.4%) achieved corrected V.A over 0.4. Most of the cases achieved the best preoperative corrected V.A with spectacles of less than 3 diopters. No severe complication occurred. CONCLUSION: Epikeratophakia is predictable with quality lens and correct surgical technique. The result suggests that the epikeratophakia is one of the best treatment for the pediatric aphakia especially for those who are not optimal for IOL implantation.

Adolescent↗
PubMed1997

[Microscopic identification of beimu grown in Yunnan province].

This paper deals with the microscopic identification of the bulbs of 5 Fritillaria species from Yunnan Province, namely: F. cirrhosa, F. cirrhosa var. purpurea, F. cirrhosa var. viridiflava, F. delavayi and F. crassicaulis. Based on the shape, size, hilum and striation of the starch grain and the cuticular veins of the upper epidermis cell of the scales, these species could be distinguished obviously.

Liliaceae↗
PubMed1997

[The combined procedure of limbal transplantation (LT) and penetrating keratoplasty (PK) for severe ocular obsolete chemical or thermal burns].

PURPOSE: To improve the prognosis of grafts for obsolete ocular chemical or thermal burns. METHODS: LT + PK or PK were performed in 28 eyes with severe chemical or thermal burns. The effects of the two groups were compared. RESULTS: In LT + PK group(12 eyes), during 5 to 28 months of follow-up, the results showed improved visual acuity in 9 eyes (75%), maintained stable epithelial adhesion without recurrent erosion or persistent epithelial defect in 11 eyes (91.67%), graft transparent in 9 eyes (75%). Nine eyes (75%) showed prevented neovascularization and conjunctival tissue from growing into graft. Allograft rejection were identified in 4 eyes (33.33%). In routine PK group (16 eyes), during 3 to 22 months of follow-up, the results showed improved visual acuity in 4 eyes (25%), maintained stable epithelial adhesion without recurrent erosion or PCED in 8 eyes (50%), graft transparent in 4 eyes (25%). Four eyes (25%) showed prevented neovascularization and conjunctival tissue from growing into cornea. CONCLUSIONS: Combined procedure of LT and PK is an effective treatment for severe ocular chemical or thermal burns. It can reduce persistent corneal epithelial defect and prevent neovascularization and conjunctival epithelial from growing into cornea thus maintaining graft transparent and improving visual acuity.

Adolescent↗
PubMed1997

The determinative role of intraoperative echo in tricuspid valvuloplasty.

A transesophageal echocardiography (TEE) was used in monitoring the operation of tricuspid valvuloplasty. Nine patients with rheumatic heart disease were studied. The results showed that intraoperative TEE was important on the improving method of tricuspid annuloplasty, it help to determine surgical procedure, control annulus-reducing procedure and assess the result immediately after operation. The results suggested that intraoperative TEE can be widely used in valvuloplasty in future.

Adult↗
PubMed1997

[Study of the relationship between human quality and reliability].

To clarify the relationship between human quality and reliability, 1925 experiments in 20 subjects were carried out to study the relationship between disposition character, digital memory, graphic memory, multi-reaction time and education level and simulated aircraft operation. Meanwhile, effects of task difficulty and enviromental factor on human reliability were also studied. The results showed that human quality can be predicted and evaluated through experimental methods. The better the human quality, the higher the human reliability.

Aviation↗
PubMed1997

[The establishment of antigen sandwiched ELISA for detection of total antibodies to hepatitis C virus].

An antigen sandwiched ELISA for detection of the total antibodies to HCV was established using genetically engineered proteins and synthesized peptides located in the structural and nonstructural regions of HCV genomes as coated antigens and were labeled by horseradish peroxidase, respectively. A comparison of antigen sandwiched ELISA with indirect ELISA showed that the sensitivity of sandwiched system (1:128) was little higher than that of indirect ELISA (1:64), the specificities of both systems were all 100%. This reagent may detect all classes of antibody to HCV in serum, mainly IgG and IgM and is a new diagnostic reagent for detection and early diagnosis of HCV infection.

Enzyme-Linked Immunosorbent Assay↗
PubMed1997

[Recombinant AAV-LMP-induced LMP specific cytotoxic response to autologous lymphoblastoid cell lines tranformed by Epstein-Barr virus].

Epstein-Barr virus is believed to be controlled in normal host by virus specific cytotoxic T lymphocytes (CTL). Although unable to eliminate EBV from the body, CTL seems to be essential in control of latently infected cells. Infusion of autologous EBV specific CTL, which can be produced in laboratory by separating lymphocytes from patients and stimulating them with EBV antigen, will provide an effective method of preventing and treating EBV-related diseases. We inserted the LMP gene of EB virus into an AAV vector pACP and packed it in Ad2 infected 293 cells by co-transfecting with plasmid Ad8, which produced the recombinant virus rAAV-LMP. The recombinant virus was used to infect stimulating cells and LMP antigen was expressed on the surface of these cells. Then the stimulating cells were irradiated and co-cultured with T lymphocytes. The EBV specific CTLs were obtained. The target cells were autologous LCLs from EBV-transformed B lymphocytes. The CTL activity was assayed by BLT activity method. The result indicated that all the four CTL strains could recognize and kill their target cells. This study has laid the technical basis for us to prevent and treat nasopharyngeal carcinoma in China with molecular biological methods.

Cell Line↗
PubMed1997

[Effects of IFN-alpha on the expressions of perforin and granzymes in IL-2 activated lymphocytes].

OBJECTIVE: To study the effect of IFN-alpha on the expressions of perforin and granzymes in IL-2-activated-lymphocytes. METHODS: NK and LAK activities were assayed by 4 hour standard 51Cr release test, the activity of perforin was detected by hemolysis method, expression of granzyme B was measured by ABC immunohistological method, expression of granzyme A was measured by BLT method. RESULTS: IFN-alpha significantly augmented the activities of NK and LAK in IL-2 activated peripheral blood lymphocytes (PBL) after 1 day culture. Perforin activity in lymphocytes was increased after 1 day exposure to IL-2 or IFN-alpha, and was enhanced when exposed to the combination of IL-2 and IFN-alpha. After 3 day culture, the perforin activity remained high in lymphocytes activated by IL-2 alone or in combination with IFN-alpha, while declined to control level in IFN-alpha exposed group. IL-2 and IFN-alpha alone or in combination had no effect on expression of granzyme A and B. CONCLUSION: IFN-alpha enhances the cytotoxicity of lymphocytes activated by IL-2. The mechanism might be that IFN-alpha upregulates the perforin expression.

Gene Expression Regulation↗
PubMed1997

[Pharmacokinetics of intravenous arsenic trioxide in the treatment of acute promyelocytic leukemia].

OBJECTIVE: In order to study the pharmacokinetics and metabolism of arsenic trioxide (As22O3), and its major side effects. METHODS: The clinical pharmacokinetics of intravenous As2O3 in 8 relapsed acute promyelocytic leukemia (APL) patients were studied by Gas-phase chromotography. RESULTS: (1) After 2 hour intravenous drips of 10mg As2O3, drug plasma maximal concentration (Cpmax) was 0.94 +/- 0.37mg/L(x +/- s), time to peak concentration (Tp) was 4hrs, T1/2 alpha and T1/2beta were 0.89 +/- 0.29hrs and 12.13 +/- 3.31hrs, respectively, apparent volume of distribution (Vc) was 3.83 +/- 0.45L, system clearance (CLs) was 1.43 +/- 0.17L/h and area under curve (AUC) was 7.25 +/- 0.97mg x h/L. Importantly, the continuous administration of As2O3 did not alter the pharmacokinetic behaviors. (2) During As2O3 therapy, 24-hour arsenic content in urine accounted for 1%-8% of the total dose (10mg) per day. And it decreased gradually after drug withdrawal. (3) Arsenic contents in nail and hair were increased continuously during As2O3 therapy. The peak concentrations could be five to seven-fold higher than that pre-treatment. It also decreased gradually after drug with drawal. CONCLUSION: As2O3 is a relatively safe and effective drug in the treatment of APL patients, in spite of certain accumulation in some tissues.

Adolescent↗
PubMed1997

[The killing effect of IL-2 and IFN-alpha activated bone marrow on K562 leukemic cell].

OBJECTIVE: To evaluate the killing effect of IL-2 and IFN-alpha activated bone marrow cells on K562 cells. METHODS: Semi-solid colony assay was used. RESULTS: Bone marrow from leukemia patients in remission was activated in vitro with IL-2 for 3 days. The activated bone marrow (ABM) displayed killing effects of 0.31 approximately 2.30 logs on K562 cells, this killing effects was further increased to 0. 30 approximately > 3.15 logs when IFN-alpha added with IL-2 to the marrow for activation. IL-2 alone or in combination with IFN-alpha showed no inhibition of CFU-GM and K562 cells. Compared with IL-2 or IFN-alpha alone, the combination of the two cytokines could more effectively maintain the killing effect of ABM on leukemic cells. CONCLUSION: IFN-alpha can augment the purging effect of IL-2 ABM and combination of the two cytokines can effectively maintain the cytotoxicity of ABM.

Bone Marrow Cells↗
PubMed1997

[Preparation and evaluation of a strong polar polymer capillary column].

A strong polar organic polymer porous layer open tubular capillary column, named OPPLOT-A column, was prepared by in situ copolymerization with the strong polar acrylonitrile as monomer and divinylbenzene as cross-linking agent. The polarity of the column is higher than that of the OPPLOT-Q, OPPLOT-R andd OPPLOT-S columns which prepared previously. The performance of the OPPLOT-A column was evaluated. It is effective to analyze alcohols, aldehydes, ketones, esters, ethers and nitriles etc., and especially for good separation of nitriles and aldehydes. The retention of the column is not influenced by water. The thermal stability of the OPPLOT-A column (200 degrees C) is lower than that of OPPLOT-Q (250 degrees C), -R (250 degrees C) and-S (210 degrees C).

English Abstract↗
PubMed1997

[Absorption spectra study for fullerene-doped in polystyrene film].

The absorption spectra of C60 and C70-doped in polystyrene film and in solution were studied. The experiment results showed that the positions of the absorption peaks for C60-doped in polystyrene film moved a little toward longer wavelength than in n-hexane, and regular solid material appeared while the ratio of C60-doped in the film increased; The absorption peaks for C70-doped in polystyrene film were almost in consistent with that in solution. We suggest that C60 molecules may be connected as "microcrystalline" in polystyrene film, while C70 may be exist as single molecule or particle less than C60 in it. The preliminary model for the growth of "microcrystslline" in polystyrene film has been proposed.

English Abstract↗
PubMed1997

[Study on the direct determination of Pb and Cd in milk powder by GFAAS].

The paper reports the direct determination of Pb and Cd in milk powder by GFAAS. The mothed does not need any pre-treatment to the samples and fully use some function of pre-treatment which the Graphite Furnace have. The result indicates that the method is simple, rapid and accurate, and the false result from any pre-treatment to the samples can be reduced. The recover rate of Pb is 100.1%, CV =2.7 ; and Cd is 98.6%, CV = 3.1 %. This method is also applied to the rapid determination of Pb and Cd in soluble samples with satisfactory results.

Analytic Sample Preparation Methods↗
PubMed1997

In vivo HIV-1 frameshifting efficiency is directly related to the stability of the stem-loop stimulatory signal.

In many retroviruses, the expression of reverse transcriptase, protease, and integrase is dependent upon a -1 frameshift event. The frameshift signal is composed of a slippery sequence where the ribosome shifts, and a downstream stimulatory sequence. In most cases, the stimulatory sequence is a pseudoknot, but in some viruses, such as human immunodeficiency virus type 1 (HIV-1), a single stem-loop is involved. Here, we analyzed the precise role of the stem-loop thermodynamic stability. We tested the frameshifting stimulatory activity of a series of HIV-1-derived sequences showing a stepwise increment of the estimated deltaG degrees. These sequences were introduced at the junction of a lacZ-luc fusion gene cloned on a versatile expression vector, and the different constructs were tested in Saccharomyces cerevisiae and in mouse NIH3T3 cells. The results showed that the frameshifting efficiency was correlated directly to the stem stability between deltaG degrees = -2.5 kcal mol(-1) and deltaG degrees = -19.4 kcal mol(-1). This demonstrates the essential role of the stability of the stem-loop and does not support the involvement of a specific RNA-binding protein target sequence. However, increasing further the stem stability led to a diminution of frameshifting efficiency, suggesting that the stem-loop acts through a precise kinetic of pausing. Because the same pattern was observed in both yeast and mouse cells, it is likely that the stimulatory mechanism is conserved through evolution.

3T3 Cells↗