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Biomedical subjects

L Xie

Publications and source records attributed to L Xie.

At least 109 records · Page 6Linked to original sources
PubMed1998

[The choice of intraocular lens before cataract extraction for cases with high myopia].

OBJECTIVE: To study the choice of diopter and size of optical portion of intraocular lens (IOL) before cataract extraction for cases with high myopia. METHODS: Extracapsular cataract extraction (ECCE) or phacoemulsification with IOL implantation was performed on 60 cases (94 eyes) with high myopia (axial length > 26mm). The posterior chamber IOL selected and inserted was the one with the diopter and size of the optical portion suitable for the recipient to have a postoperative low myopia and easy to be examined with an ophthalmoscope. RESULTS: The postoperative eyes were of low myopia, -2.07 +/- 1.95 D. The larger size of optical portion was more suitable for ocular fundus examination. Great care was taken for phacoemulsification for cataractous nucleus below III grade. CONCLUSIONS: For patients with axial myopia, the IOL implanted should create low myopia postoperatively. Larger optic size is better for fundus examination. Phacoemulsification can produce less astigmatism and damage, but the indication must be controlled strictly.

Adolescent↗
PubMed1998

[Accuracy and predictability of photorefractive keratectomy for astigmatism correction].

OBJECTIVE: To study the accuracy and predictability of photorefractive keratectomy (PKR) for astigmatism correction. METHODS: 53 eyes of 30 cases with compound myopia astigmatism and 33 eyes of 23 cases with simple myopia were treated with PRK and followed up for 6 months. The differences of corneal refractive power provided by corneal topography between the values at postoperative 6 months and that of the preoperative one were calculated with Holladay Ways to get real corrective degree and axis of astigmatism. The results were analyzed and compared with the preoperative predicted values. RESULTS: Six months after PRK, among the compound myopia astigmatism group, the ratio of over correction or under correction of real corrected astigmatic power within +/- 0.50D was 60.4%, the ratio of axis deviation between real and predicted correction within +/- 15 degrees was 58.5%. Among simple myopia group, 48.5% appeared more than -0.50 D myopia astigmatism in real correction, and the cylinder axis position was within 180 degrees +/- 44 degrees. The ratios of uncorrected visual acuity after PRK in the two groups equal to or better than 1.0 were 77.4% and 78.8%, respectively. There was no difference between these two groups (chi(2) = 0.024, P > 0.75). CONCLUSIONS: The method of myopia astigmatism correction using this PRK machine needs to be improved. After PRK treatment, the visual acuity of myopia astigmatism is similar to that of simple myopia group. It shows good efficacy. It is indicated that for myopia astigmatism lower than -2.00D, especially for the astigmatism with the rule, PRK could be performed according to equivalent spherical value.

Adolescent↗
PubMed1998

[Biosynthesis of a single peptide chain containing human chorionic gonadotropin beta and ovine common alpha subunits tandem].

hCG beta-oLH alpha chimeric cDNA was constructed by using overlapping PCR to contact the codons of C-terminal end of hCG beta with the codons of N-terminal end of oLH alpha, then it was subcloned into nuclear polyhedrosis virus (AcNPV) expression vector pVL1393 to construct expression vector pVL1393-hCG beta-oLH alpha. The insect cells (Sf9) were cotransfected by the expression vector pVL1393-hCG beta-oLH alpha and BaculoGold AcNPV linearized genomic DNA, and recombinant viruses AcNPV-hCG beta-oLH alpha were screened out by plaque assay. Further the insect cells were infected by the recombinant viruses, the recombinant hCG beta-oLH alpha was purified by immunoaffinity chromatography column coupling anti-hCG beta monoclonal antibody from the conditioned media of infected cells. The results of SDS-PAGE silver staining and western blotting showed that hCG beta-oLH alpha single peptide chain had apparent molecular weights of 40.5 kD and 38.0 kD under non-reducing and reducing conditions respectively, indicating the occurrence of disulfide bonds and significant tertiary structure in the single peptide chain. From the results of competitive inhibition of 125I-hCG beta binding we can conclude that the anti-hCG beta antibody-binding activity of hCG beta-oLH alpha chimera is lower than that of native hCG, but higher than that of native hCG beta. Therefore, we assume that the hCG beta-oLH alpha chimera should have potential application as a target antigen of anti-hCG fertility regulatory vaccine.

Animals↗
PubMed1997

Argininosuccinate synthetase overexpression in vascular smooth muscle cells potentiates immunostimulant-induced NO production.

Immunostimulants trigger vascular smooth muscle cells (VSMC) to express both the inducible isoform of NO synthase (iNOS) and argininosuccinate synthetase (AS). With constitutively expressed argininosuccinate lyase (AL), AS confers cells with an Arg/Cit cycle that can sustain NO production via continuous regeneration of the NOS substrate, L-arginine (Arg), from the NOS coproduct, L-citrulline (Cit). To assess whether NO synthesis can be rate-limited by Arg recycling, we tested whether AS-overexpressing cells have an enhanced capacity for immununostimulant-induced NO synthesis. Rat VSMC were stably transfected with human AS cDNA in a eukaryotic cell expression vector, driven by a strong viral promoter. AS activity in transfected VSMC exceeded that induced in untransfected cells treated for 24 h with a combination of bacterial lipopolysaccharide and interferon-gamma (LPS/IFN). AS activity was predominantly associated with membranes but was also found in cytosol. Recombinant AS was purified from cytosol and possessed a specific activity exceeding that reported for native AS. Western blotting verified the basal expression of AS antigen in membranes from untreated AS-transfected VSMC and from untransfected VSMC after 24 h exposure to LPS/IFN. Epifluorescence histochemistry revealed a punctate distribution of AS antigen in transfected cells, consistent with a predominant membrane localization. Remarkably, on a per cell basis, LPS/IFN-induced NO production was 3-4-fold greater in AS-transfected cells than untransfected VSMC. In untransfected VSMC, maximal NO production during 48 h required millimolar Arg; notably, Cit was needed at approximately 3-fold higher concentrations than Arg for a comparable NO synthesis rate. In contrast, AS-transfected VSMC utilized Arg and Cit equi-effectively and at much lower concentrations; 100 microM of either precursor supported a maximal rate of NO synthesis for 48 h. The enhanced ability of AS-transfected cells to produce NO, compared with untransfected cells, could not be ascribed to differences in iNOS protein content or LPS/IFN potency for immunoactivation. We conclude that transfection with AS provides a continuous flux of Arg which drives NO synthesis in immunoactivated VSMC. Arg regeneration by AS is rate-limiting to NO synthesis and apparently provides iNOS with a preferred cellular source of Arg. In accord with the reported "channeling" of substrates by urea cycle enzymes, we hypothesize that the Arg/Cit cycle sequesters a discrete pool of recyclable substrate that sustains high-output NO synthesis.

Adjuvants, Immunologic↗
PubMed1997

Graphical evaluation of alkylation of myosin's SH1 and SH2: the N-phenylmaleimide reaction.

Previous assertions about the effect of alkylation of SH1 and SH2 on the myosin high-salt calcium and EDTA ATPases have been summarized, and a simple procedure for obtaining the fractional labeling of SH1 and SH2 after treatment of myosin with alkylating agents has been derived. A simple graphical procedure for illustrating the degree of preference of a particular alkylating agent for SH1 over SH2 has also been developed. The procedures we developed were validated by applying them to two previously studied compounds, 4-(2-iodoacetamido)-TEMPO and 2,4-dinitrofluorobenzine, and then were used to determine a procedure for maximizing the extent of labeling of SH1 alone by N-phenylmaleimide, a compound not previously studied in this manner. It was found that approximately 80% of the SH1 sites could be alkylated without significant alkylation of SH2.

Alkylation↗
PubMed1997

Integrated approaches to the design of media and feeding strategies for fed-batch cultures of animal cells.

Animal cell culture has become an important approach for the production of biologically functional proteins for human therapy. The quantity and quality of protein production are influenced by the culture environment, which is subject to change over the course of cell cultivation. Therefore, it is vital to design an optimal culture environment and control it within an optimal region to maximize the productivity. This requires that the factors affecting the culture environment (nutrient concentrations, by-product accumulation, pH and osmolality) and cell growth be integrated into the design of culture media for fed-batch animal cell cultures.

Animals↗
PubMed1997

Anti-AIDS agents--XXVI. Structure-activity correlations of gomisin-G-related anti-HIV lignans from Kadsura interior and of related synthetic analogues.

Bioactivity-directed fractionation of an ethanolic extract of the stems of Kadsura interior led to the isolation and identification of 12 known lignans (1-12). Seven of these compounds (1, 6, 8-12) were active as anti-HIV agents. Gomisin-G (11) exhibited the most potent anti-HIV activity with EC50 and therapeutic index (TI) values of 0.006 microgram/mL and 300, respectively. Schisantherin-D (6), kadsuranin (8), and schisandrin-C (10) showed good activity with EC50 values of 0.5, 0.8, and 1.2 micrograms/mL, and TI values of 110, 56, and 33.3, respectively. Ten related synthetic biphenyl compounds, five variously substituted bismethylenedioxy, dimethoxy, and dimethoxycarbonyl isomers (18-22) and five brominated derivatives (23-27) also were evaluated for inhibitory activity against HIV-1 replication in acutely infected H9 cells. The total syntheses of two new isomers (21 and 22) are reported for the first time. The anti-HIV data indicated that the relative position and types of substituents on the phenolic hydroxy groups of either the natural lignans or the synthetic biphenyl compounds rather than the numbers of bromine(s) on the aromatic rings are of primary importance. In the cyclooctane ring of the natural lignans, the position and substitution of hydroxy groups are also important to enhanced anti-HIV activity.

Anti-HIV Agents↗
PubMed1997

The natural history of borderline hypertension in a Chinese population.

One hundred and thirty-one borderline hypertensive patients were followed up for 17 years. A cohort of normotensives strictly matched by age, sex, region and occupation served as controls (1:1). It was found that 64.6% of borderline hypertensive patients developed into established hypertensives after 17 years follow-up, 25.5% restored to normotensives and 13.8% remained unchanged. The total mortality rate of borderline hypertensives was higher than that of normotensives (27.9 vs 13.4/1000 person years), and the relative risk of total death in borderline hypertensives was 2.35. The main cause of death was stroke, accounting for 42.5% of the total death rate. The relative risk rates of occurrence and death associated with stroke were 8.3 and 11.6, respectively. It is concluded that the main complication of borderline hypertension was stroke rather than coronary heart disease, which was similar to that of established hypertension in this area. Part of the borderline hypertensives need to be treated to reduce the risk of cardiovascular complications.

Adult↗
PubMed1997

[A preliminary report of microlamellar keratectomy for correction of high myopia].

OBJECTIVE: To evaluate the preliminary results of high myopia corrected by microlamellar keratectomy (MLK). METHODS: 73 eyes of 43 patients with high myopia were treated by MLK. The preoperative refraction ranged from -7.00 to -32.00 D (mean -18.45 +/- 6.18 D). All the operations were performed with a special apparatus made in America for MLK. RESULTS: At 6 months after surgery, in the 73 eyes with complete data, all the uncorrected visual acuity and corrected visual acuity were betterthan or equal to their preoperative ones respectively. Uncorrected visual acuity was better than or equal to the preoperative corrected visual acuity in 51 eyes (71.83%). The correction of refraction in 63 eyes (86.30%) was within +/- 4.00 D of the intended correction. No severe complications occurred during and after operation. The postoperative status of refraction was stable. CONCLUSIONS: MLK is effective in high myopia treatment and has some special advantages compared with radial keratotomy, photorefractive keratectomy, automated lamellar keratoplasty and excimer laser in situ keratomileusis. But the procedure is influenced by several factors, and the predictability of this procedure is merely fair. The authors suggest that this kind of procedure be done with excellent microsurgery equipment, microsurgical skills and much more clinical experiences in managing corneal disorders.

Adolescent↗
PubMed1997

[Cataract extraction combined intraocular lens implantation through corneal incision].

OBJECTIVE: We reported the clinical results of the extracapsular cataract extraction (ECCE) with intraocular lens (IOL) implantation through a corneal incision. METHODS: The ECCE with IOL implantation was performed through a stepped corneal incision within limbus 1.0-1.5 mm. The changes of intraocular pressure (IOP), endothelia and astigmatism were observed. RESULTS: The IOP has no significant changes, and the rate of endothelial cells loss (12.55%) also has no significant differences compared with routine cataract extraction. The corneal astigmatism became 0.96 DC with the rule after operation. CONCLUSION: For complicated cataract after trabeculectomy, uveitis with pupillary block, and serious diabetic cataract, the intraocular surgery through a corneal incision is effective and safe.

Adolescent↗
PubMed1997

[A clinical investigation on foldable intraocular lens implantation].

OBJECTIVE: The results of phacoemulsification (phaco) operations which were performed with 3.2 mm incision and foldable intraocular lens (IOL) implantation were reviewed. METHODS: On forty-nine eyes with cataract of forty-two cases phaco and foldable IOL implantation was randomly performed. The results of the postoperative vision, the refraction and the loss rate of corneal endothelial cell were analyzed. RESULTS: By the 7th postoperative day, the uncorrected vision in 32 eyes (65.31%) was 1.0 or better. The visual acuity in forty-one eyes (83.67%) was 1.0 or better after 3 months of operation. The loss rate of endothelial cells was 11.72%. In the comparison between the postoperative and preoperative corneal astigmatism, the mean former one became against the rule for 0.10 DC. CONCLUSIONS: The small incision operations not only can provide a satisfactory early postoperative visual acuity with a slight corneal astigmatism, but also can reduce the time for suturing and avoid the harmful effects of stitches.

Adult↗
PubMed1997

[Effect of electric field on erythrocyte sedimentation rate. VI--dependence of electric field pattern].

An automatic analyzer of RBC rheological parameters and a microscopic morphological observation technique were employed to investigate the effect of three electric field patterns on erythrocyte sedimentation and aggregation in a physiological saline solution and in autologous plasma, respectively. Experimental results indicate that in a physiological saline solution: 1) Erythrocytes present a lightly aggregation and settle faster by an alternative current electric field; 2) There exists no erythrocyte aggregation by a direct current electric field of constant current and the enhancement of erythrocyte sedimentation is caused only by the action of electric force; 3) Time courses of erythrocyte sedimentation fit well with an exponential type curve by a direct current electric field of constant voltage, and this exponential type sedimentation curve is not caused by erythrocyte aggregation but caused by the decrease of circuit current with time duration. Also shown by experimental results is that the above three electric field patterns all affect the erythrocyte sedimentation in antologous plasma in different contents, which predicts some change in erythrocyte aggregation behavior in autologous plasma by an external electric field.

Blood Sedimentation↗
PubMed1997

[Effects of octacosanol in food physiological parameters in tail-suspended rats].

The purposes of the experiment were to observe the physiological effects of octacosanol in food on tail-suspended rats and to investigate the possibility of using octacosanol in health food for astronauts. 24 male Wistar rats were randomly divided into free action control, tail-suspension and tail suspension plus octacosanol (TSO) groups. Octacosanol was emulsified into water by supersound and given to TSO rats with a dosage of 25 mg/kg wt d. The results showed that octacosanol elevated the weight of thymus, improved biomechanical properties of the femur and improved membrane fluidity of red blood cell. It suggests that octacosanol can counteract some effects of simulated weightlessness on rats. Therefore, octacosanol may be added to natural foods to benefit the health of cosmonauts.

Aerospace Medicine↗
PubMed1997

[Quantitative analysis of phoxim and cypermethrin using wide bore capillary column gas chromatography].

A compound pesticide, 20% P-C emulsion, consisting of 18.5% phoxim and 1.5% cypermethrin pesticides and other accessory agents is especially effective in controlling and killing boll worms. For its quality control some difficulties were encountered. In this paper we propose a simple and practical method for GC analysis of the product by use of a short wide bore capillary column (HP-1, 5m x 0.53mm x 2.65microm), high carrier gas flow rate and high-speed temperature programming etc.. Content analysis of efficient composition of "20% P-C emulsion" was completed under the chromatographic conditions using methyl parathion as an internal standard. Coefficient of variation of phoxim and cypermethrin were 0.67% and 1.0% respectively.

Chromatography, Gas↗
PubMed1997

Impact of social changes on female mentally disordered offenders from 1980 to 1994 in Japan.

Social change, particularly in mental health policy, may affect the distribution of crime and the legal process. This article presents trends in female crimes during a 15-year period (1980 to 1994) and examines the characteristics of the 1980 and the 1994 group of female mentally disordered offenders (MDOs) in Japan. Data were obtained from the prosecutor's files on a total of 2,094 MDOs who were not prosecuted, or whose criminal responsibility was judged as diminished, or who were exempted due to mental disorders in 1980 and 1994 throughout Japan. Female MDOs accounted for 270 (12.9%) of these cases. A comparison was made between the 1980 group (140 women) and the 1994 group (130 women) in regard to demographic status, criminal variables, psychiatric variables, and legal dispositions. Findings revealed a parallel relationship between female criminals and female MDOs. In both the female criminals and female MDOs, the trend was toward a decrease in homicides and an increase in larceny and drug-related crimes. The 1994 group was more likely to have an even distribution across age groups, have more employment and more job change experience, live more independently, and to have committed more nonviolent crimes, and have more prior crime records than the 1980 group. There was no significant difference in their homicide victims or in the index diagnoses between the two groups. Compared with the 1980 group, the 1994 group was significantly older (40 years versus 36 years on average), had received more outpatient and community mental health services, had been charged more often with larceny, had higher criminal recidivism rates, and had experienced a more simplified legal process as well. The effect of deinstitutionalization is also discussed.

Adult↗
PubMed1997

Microlamellar keratectomy for correction of high myopia.

OBJECTIVE: To evaluate the preliminary results of high myopia correction by microlamellar keratectomy (MLK). METHODS: Seventy-three eyes of 43 patients with high myopia were treated by MLK. The preoperative refraction ranged from -7.00D to -32.00D (mean -18.45D +/- 6.18D). All the operations were performed with the special apparatus for MLK. RESULTS: At 6 months after surgery, in the 73 eyes except 2 with new other symptoms, all the uncorrected visual acuity and corrected visual acuity were better than or equal to their preoperative ones respectively. Uncorrected visual acuity was better than or equal to the preoperative corrected visual acuity in 51 eyes (71.83%). No severe complications occurred during and after operation. The postoperative refractive status was stable. CONCLUSIONS: MLK is effective to reduce high myopia and has some special advantages as compared with radial keratotomy (RK), photorefractive keratectomy (PRK) and laser in-situ keratomileusis (LASIK). But influenced by several factors, the predictability of this procedure is merely fair. It is suggested that this kind of procedure must be done with excellent microsurgery equipments, microsurgical skills and much more clinical experience of managing corneal disorders.

Adolescent↗