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Biomedical subjects

H Shen

Publications and source records attributed to H Shen.

At least 181 records · Page 10Linked to original sources
PubMed1999

Immunosuppression for neural xenografts: a comparison of cyclosporin and anti-CD25 monoclonal antibody.

OBJECT: The goal of this study was to compare the effects of short- and long-term immunosuppression induced by cyclosporin with those of immunosuppression induced by a monoclonal antibody against the rat interleukin-2 receptor (anti-CD25 mAb) in rats with xenografts. METHODS: The authors compared the in vivo function and final histological characteristics of fetal mouse mesencephalon xenografts in hemiparkinsonian rats in which immunosuppression was induced by: 1) a short course (2 weeks) of cyclosporin; 2) a long course (8 weeks) of cyclosporin; or 3) a short course of treatment with anti-CD25 mAb. Adult Wistar rats were unilaterally lesioned with 6-hydroxydopamine in their medial forebrain bundle, after which their rotational behavior in response to methamphetamine was quantified. Four groups of 20 rats with rotations numbering greater than six turns per minute received fetal mouse mesencephalon transplants to their dopamine-denervated striatum. Group 1 received no immunosuppression therapy; Group 2 received daily intraperitoneal injections of 10 mg/kg cyclosporin for 2 weeks; Group 3 received daily intraperitoneal injections of 10 mg/kg cyclosporin for 8 weeks; and Group 4 received daily intraperitoneal injections of 1 mg/kg anti-CD25 mAb for 2 weeks. The rats were tested for rotational behavior every 4 weeks and killed after 16 weeks. Surviving xenografts were assessed using immunohistochemical staining for a mouse neuronal marker (Thy-1.2). Sixteen weeks after transplant, there were significantly more surviving xenografts in Groups 3 (p < 0.001) and 4 (p < 0.001) compared with control Group 1 (Fisher's exact test) and significantly better functioning xenografts in Groups 3 (p < 0.01) and 4 (p < 0.05) compared with control Group 1 (contrasts of groups following analysis of variance with Bonferroni correction). CONCLUSIONS: A short course of anti-CD25 mAb-induced immunosuppression was as effective as a long course of cyclosporin-induced immunosuppression in this model.

Animals↗
PubMed1999

Glutathione conjugate interactions with DNA-dependent protein kinase.

A photoactivatable glutathione-drug conjugate (35)S-labeled-azidophenacyl-glutathione (APA-SG) was synthesized and used to identify protein(s) involved in recognition and/or transport of glutathione conjugates of electrophilic drug species. A approximately 460-kDa protein was found to be highly labeled by (35)S-labeled APA-SG in an Adriamycin-resistant HL-60 (HL-60/ADR) cell line and identified as the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) by amino acid sequence analysis, Western blot, and immunoprecipitation with specific antibodies. Binding specificity was confirmed by competition isotope dilution assays with purified proteins. A 15- to 20-fold increase in DNA-PKcs expression in the HL-60/ADR cell line was accompanied by an equivalent increase in (35)S-labeled APA-SG binding. APA-SG, along with other glutathione conjugates and analogs inhibited the DNA-PK-mediated phosphorylation of an in vitro peptide substrate in a concentration-dependent manner. Using different antibodies to immunoprecipitate the individual components of the DNA-PK complex (DNA-PKcs, Ku70, and Ku80), it was shown that APA-SG caused a destabilization of the trimeric holoenzyme complex by dissociating the catalytic subunit from the Ku heterodimer. These data suggest that the kinase-mediated signaling is inhibited when glutathione conjugates bind to DNA-PKcs and may also indicate a possible strategy for design of novel DNA-PK inhibitors.

Amino Acid Sequence↗
PubMed1999

[Analysis of fusion points in hybrid genes and gene deletion for congenital red-green color vision defects].

OBJECTIVE: To investigate gene deletion and the fusion points of hybrid genes in congenital red-green color vision defects. METHODS: Genomic DNA was collected from 11 protans, 19 deutans and 5 normal controls. Promoter and exons 2-5 of the red and green pigment genes in these subjects were analyzed by using PCR-Heteroduplex-SSCP analysis. The origin and component of each individual gene were determined by comparison with the patterns of known sequence of the red and green visual pigment genes. RESULTS: Fourteen out of the 30 patients with red-green color vision defects were found to have hybrid gene. The fusion points of the hybrid gene were located in exon 1-intron 1(4 cases), introns 2-3(5 cases) and intron 4 (5 cases). CONCLUSION: The fusion point of a hybrid gene may occur in exon 1-intron 1 and intron 4 as well as in introns 2-3(including exon 3).

Artificial Gene Fusion↗
PubMed1999

Glutathione peptidomimetic drug modulator of multidrug resistance-associated protein.

The peptidomimetic drug gamma-glutamyl-S-(benzyl)cysteinyl-R-(-)-phenyl glycine diethyl ester (TER199) is an analog of glutathione designed to be an isozyme-specific inhibitor of GSTP1-1 protein1-1. This compound (and the de-esterified moiety) is shown to be an effective inhibitor of multidrug resistance-associated protein1 (MRP1)-mediated drug resistance. Kinetic analyses revealed that gamma-glutamyl-S-(benzyl)cysteinyl-R-(-)-phenyl glycine reversibly inhibits the transport of 2,4-dinitrophenyl-S-glutathione with a K(i) of 752 microM. TER199 reversed the accumulation deficit of daunorubicin in MRP1-transfected NIH3T3 fibroblasts and maintained intracellular levels for >2 h after daunorubicin removal. Cytotoxicity assays revealed that TER199 significantly reversed the resistance of MRP1-transfected NIH3T3 cells for vincristine, doxorubicin, etoposide, and mitoxantrone. HL-60 cells made resistant to TER199 by chronic, long-term selection had increased mRNA and protein levels of multidrug resistance-associated protein, MRP1, and gamma-glutamyl cysteine synthetase heavy and light subunits (the rate-limiting enzyme in GSH synthesis). In spite of increased gamma-glutamyl cysteine synthetase, their glutathione content was reduced approximately 35% from that of parental HL-60 cells. These cells also exhibited a drug resistance profile commensurate with the previously described MRP1 overexpressing phenotype, with resistance to Vinca alkaloids, epipodophyllotoxins, and anthracyclines; additional cross-resistance to paclitaxel (Taxol), mitoxantrone, and 5-fluorouracil was observed.

3T3 Cells↗
PubMed1999

[The use of risk factors scoring method in screening for undiagnosed diabetes in general population].

OBJECTIVE: Based on an epidemiological survey of NIDDM in the general population, two sub-population groups were selected to develop a screening method on risk factors to identify people at increased risk for undiagnosed diabetes. METHODS: Logistic regression analysis on the original data of population A was carried out to screen the main risk factors of diabetes. The score of the variable was determined based on the OR value and the aggregate score was used to predict the risk of undiagnosed diabetes. Both validity and effectiveness of the method were evaluated in population B. RESULTS: Results showed that the risk of having diabetes in the population increased along with aggregate scores of the method. Trend chi 2 test showed statistical significance (P < 0.01). When the threshold value was set up at 7, both sensitivity and specificity for identifying undiagnosed diabetes were 74.3% and 63.2%, respectively making the positive predictive value 4.2% and negative predictive value 99.2%. CONCLUSION: The benefits of this screen method seemed to be simple, economical and helpful to obtain a satisfactory response rate. The method could be used for health education and to identify people (community) at high risk for potential diabetes. It was predicted that this screening method could serve as an effective and useful tool for mass screening of NIDDM.

Adult↗
PubMed1999

[Early cardiac myocyte membrane changes in severely burned rats: a spin labding-ESR study].

OBJECTIVE: To demonstrate the mechanism of early cardiac myocyte membrane damage at molecular level in severely burned rats. METHODS: SD rats were randomly divided into sham-burn and burn groups. A 30% TBSA burn was created in burn group. Hearts were obtained at different time postburn. Cardiac myocytes isolated by collagenase using Langendoff perfusion apparatus were spin labeled with 5-doxylstearic acid (5NS), 16-doxylstearic acid (16NS) and 3-maleidoproxyl (3MP). The order parameters (S value), hs/hw ratio and rotational correlation time (tau c) were measured according to the spin labeling-ESR spectra. RESULTS: The S value of the polar head-group region of membrane lipid, as reported by 5NS, did not changed significantly, while that of the lipid in the hydrophobic midzone, as reported by 16NS, increased significantly. The hs/hw ratio of 2 and 6 hours postburn groups increased significantly postburn compared with that of the sham-burn group, and so did the rotational correlation time in 1 to 12 h postburn groups. CONCLUSION: There were structural and functional changes in cardiac myocyte membrane after burn injury. They were characterized by decreased fluidity in the deeper part of membrane lipid, configurational changes and motion restriction in membrane proteins. They could affect the normal performance of cardiac function.

Animals↗
PubMed1999

[Colorectal cancer: lymphatic metastasis and choice of operation].

OBJECTIVE: To study lymphatic metastasis of colorectal cancer for deceding the of dissection extent of dissection. METHODS: Six hundred and twenty-three lymph nodes from 74 cases of colorectal cancer were analyzed after D(3) resection. They were classified into peritumor, longitudinal spread, and upward spread groups. The metastasis rate of lymph node and its incidence were calculated. RESULTS: The metastasis rate of lymph node and its incidence in the peritumor, longitudinal spread, and upward spread (N(2) and N(3)) groups were 47.2% and 38.6%, 22.8% and 18.6%, and 29.7% (20.3% and 9.4%) and 10.2% (19.0% and 5.3%), respectively. The distribution rate of metastatic lymph node was 61.2%, 17.1%, and 21.6% in the peritumor, longitudinal spread, and upward spread groups, respectively. Within 2.0 cm on the anal side of rectal cancer, the metastasis rate was 3.7%, whereas in 2.0 - 4.0 cm no metastasis was observed cancer at the lower part of the rectum demonstrated a higher lateral metastasis rate. CONCLUSIONS: Colorectal cancer tends to metastasize to longitudinal and the risk of metastasis increased in the stage of pT(3) and pT(4) or low differentiation stage. Jump metastasis is also a feature. D(3) radical resection is necessary for colorectal cancer, but extended lateral lymph node needs enectomy or total mesorectal excision. No residual tumor tissue exists at the anastomosis site after low anterior resection when the excision distance is beyond 2.0 cm from the anal margin of rectal cancer.

Adult↗
PubMed1999

[A study on family aggregation of type 2 diabetes mellitus].

OBJECTIVE: To estimate the genetic susceptibility and its relative risk (RR) in the first degree relatives of type 2 diabetes mellitus (DM) through family aggregation analysis. METHODS: A population-based case-control study including 654 pedigrees (363 index cases and 291 controls) was carried out. RESULTS: The prevalence rate in the first degree relatives of DM probands was 3.94%, significantly higher than that in the controls (1.09%), with a relative risk of 3.62 (chi(2) = 36.5, P < 0.001). The RRs in different consanguineal relatives were all higher than 3.0. The younger was the probands at diagnosis for DM, the higher its prevalence rates and RRs among their relatives was and the more likelihood that more than one case of DM occurred in them. CONCLUSION: Significant family aggregation and higher genetic susceptibility were found in the first degree relatives of DM, on whom prevention and treatment for DM should be focused.

Adult↗
PubMed1999

[The significance of endometrial biopsy during luteal median phase in diagnosis of luteal function].

OBJECTIVE: To investigate the significance of progesterone profile and endometrial biopsy during luteal median phase in diagnosis of luteal function. METHODS: The progesterone profile during median luteal phase and endometrial histology during median and late luteal phase of 53 infertile women with infertile and recurrent abortion for unknown reasons were studied. RESULTS: Retarded endometrial development occurred in the median luteal phase in 24 of the 53 cases, 9 of which lasted into the late phase. The average progesterone profile of these patients was markedly lower compared with the control group (P < 0.05). However, the average progesterone profile remained normal in the other 13 cases, in whom, RED got normalized in the late luteal phase. Endometrial biopsies taken during the median and late luteal phase from the rest of 29 cases were normal. CONCLUSIONS: In patients with retarded endometrial development during the full luteal phase, luteal function was decreased, but in patients with retarded endometrial development only during the median luteal phase, luteal function appeared to be normal.

Abortion, Habitual↗
PubMed1999

[Study of the immunological tolerance induced by peripheral intravenous infusion of donor-specific antigens].

In the experiment, donor specific tolerance was induced by DST, DSSL and DSBM through peripheral intravenous transfusion in rat cervical cardiac transplantation model. The results showed there were significant differences in graft survival time between the blank control group and the other groups (P < 0.05). The mean graft survival time days of the DST, DSSL and DSBM groups were 28.9 +/- 13.7, 42.9 +/- 6.6 and 40.3 +/- 11.6 days, respectively. The effect of component infusion was obviously better than that of DST (P < 0.05), but no statistical difference was observed between DSSL and DSBM. CsA gave a noticeable synergistic effect to the induction of immunological tolerance. MLR and CD8+ T cell were remarkably reduced(P < 0.05) in the cases of component transfusion. This study suggested that components transfusion may be of clinical use for donor-specific tolerance inducing.

Animals↗
PubMed1999

[Dual window factor analysis for data of hyphenated chromatography].

A new method, dual window factor analysis (DWFA), used for the qualitative and quantitative analysis of target components hidden in chromatographic overlapping peaks of hyphenated methods is proposed in this paper. It's based on the characteristic information of the spectrum of the component. This method can directly be used for the qualitative analysis and the resolution of the spectrum and chromatogram of target components. Therefore, it is appropriate for the qualitative and quantitative analysis of the desired components in multicomponent complex system with hyphenated methods. DWFA is successfully applied to the analysis of the 4 components overlapping peak, and the results show that excellent correlations between resolved chromatographic peak area and mass concentration are kept in each of the 4 components.

Chlorophenols↗
PubMed1999

[Determination of B(a)p contents of pine tar and its extractives].

In this paper, the B(a)P contents of pine tar and its extractives A, B were determined by PC-Scanning method. After combining extraction by caffeine and formic acid with PC-Scanning method, the B(a)P contents were obtained. The results showed the B(a)P contents of pine tar and its extractives A, B were 6171.3 ppb, 2285.2 ppb, 129.6 ppb, among them, the B(a)P content of B was the lowest.

Benzo(a)pyrene↗
PubMed1999

[Genotype-phenotype correlation in Chinese patients with retinitis pigmentosa due to rhodopsin mutation].

PURPOSE: To investigate the genotype-phenotype correlation in Chinese patients with retinitis pigmentosa caused by rhodopsin gene mutation. METHODS: On the basis of the onset of symptoms, degree of morphological changes and progression of visual disability in three (3/83) patients with identified mutations, the correlation of the phenotype with the corresponding mutations was assessed. RESULTS: There was a certain degree of allele-specificity. Severe form of retinitis pigmentosa was found in patients with mutation in the cytoplasmic domain and mild form of retinitis pigmentosa in patients with mutation in the intradiscal domain. CONCLUSION: Although there is a certain relation between the mutant rhodopsin and ocular manifestation, we need to accumulate more materials before relating a rhodopsin mutation to a specific phenotype.

Adult↗
PubMed1999

Differential gene expression in retina of myopic chicken eyes using mRNA differential display.

PURPOSE: To study differentially expressed genes in retina of experimental myopic chicken. METHODS: Experimental myopia in chicken was induced by form-deprivation. The mRNA in chicken retina was analyzed by using differential display. RESULTS: Experimental myopia was successfully induced in chicken through form-deprivation. Differentially expressed gene fragments were detected in retina of chicken with myopic development and recovery as compared with normal controls. CONCLUSION: The differential display of mRNA may be a useful way in cloning myopic-related genes.

Animals↗
PubMed1999

[Study on the surface diffuse reflectance ultraviolet-visible spectra of the multicomponent metal catalysts].

In this paper, the surface diffuse reflectance ultraviolet-visible spectra (DRUVS) of two and three components supported metal catalysts for methanation of CO2 by hydrogenation were studied, and the relationship between the activity of catalytic-hydrogenation and the interaction among the components of the catalysts was revealed. Based on the analysis of the DRUVS of the catalysts with defferent amount of promoters in two component catalysts system, the dependence relationship between the characteristic strength of the DRUVS and the catalytic activity was worked out.

English Abstract↗
PubMed1999

[Determination of protein in urine by spectral probe of molybdenum(VI) salicylfluoronate complex].

The absorption spectral behavior of binding reaction of molybdenum(VI)-salicylfluoronate on bovine serum albumin was investigated. A novel method for the determination of protein in urine using Mo(VI)-salicylfluoronate complex as a spectroprobe was developed. The maximum binding number (n) of molybdenum complex to BSA was found to be 100. The molar absorptivity of binding product at 575 nm was 2.86 x 10(6) L x mol(-1) x cm(-1). The method possesses high sensitivity as well as high selectivity. It could be used to determine protein in human urine directly. The relative standard deviation for the determination is 1.5%.

Humans↗