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Biomedical subjects

L Zhu

Publications and source records attributed to L Zhu.

At least 325 records · Page 18Linked to original sources
PubMed1997

Antagonistic effects of extract from leaves of ginkgo biloba on glutamate neurotoxicity.

AIM: To determine whether the extract of leaves of Ginkgo biloba L (EGb) and several active constituents of EGb have protective effects against glutamate (Glu)-induced neuronal damage. METHODS: Microscopy and image analysis of nucleus areas in the arcuate nuclei (AN) of mice were made. The neuronal viability in primary cultures from mouse cerebral cortex was assessed using MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide] staining and the intracellular free calcium concentration ([Ca2+]i) of single neuron was measured using Fura-2. RESULTS: EGb (2.5 mg.L-1) and its constituent ginkgolide B (Gin B, 2 mg.L-1) protected the neuronal viability against Glu-induced injury, and prevented the Glu-induced elevation in [Ca2+]i. EGb (3-10 mg.kg-1) attenuated the decrease of nucleus areas in arcuate nuclei induced by Glu (1 g.kg-1, s.c.). CONCLUSION: EGb and Gin B prevent neurons from Glu neurotoxicity through reduction of the rise in [Ca2+]i.

Animals↗
PubMed1997

[Surgical consideration in congenital partial atrioventricular septal defect in 59 patients].

We report surgical anatomic characteristics, timing of surgery, corrective methods of partial atrioventricular defect and prevention of complications. In the past 15 years, we operated on 59 patients with partial atrioventricular septal defect, associated with conduction abnormality in 39 patients, common atrium in 2, mitral insufficiency (MI) in 54, tricuspid insiufficiency in 29, andunroofed coronary sinus in 6. One patient could not wean from cardiopulmanary bypass and died during operation. After surgery, 5 patients had moderate residual MI, and 1 complete heart block. During 1 to 16 years of followup, all but 1 patient with class III (NYHA) had satisfactory results.

Adolescent↗
PubMed1997

[Clinical application of transmyocardial laser revascularization].

Transmyocardial laser revascularization (TMLR), a new technique, provides direct perfusion of ischemic myocardium via laser-created transmural channels. From 1995 to 1996, we treated 7 patients (mean age 60 years, all men) with TMLR. Preperatively, 5 patients were in angina class (C. C. S) 3-4 and 2 patients had unstable angina. To identify the location and extent of their reversible ischemia, the coronary angiogram, 99mSPECT and/or dobutamine echocardiography was performed before operation in 7 patients. Through a left anterior thoractomy in the fifth intehcostal space, heart exposure was gained. With the use of a 700-watt CO2 laser, TMLR was performed on the beating heart. An average of 22 +/- 3 channels were created in 45 minutes with a total operative time of less than 2 and half hours. The in hospital mortality was one of 7 patients. Follow-up ranged from 2 to 12 months (accumulated 48 patient-months). Postoperatively, the relief of angina was noted in 6 patients. Postoperative SPECT and dubatamin-UCG were obtained at 3, 6, and 12 months. (99mTc) SPECT showed a significant improvement of myocardial perfusion in the area of reversible ischemia. Dobutamin-UCG documented an increase in the ventricular wall motion and LVEF in 2 patients as compared with basline. These early results indicate that TMLR may provide angina relief, improve myocardial perfusion and increase cardiac function for patients with ischemic heart disease.

Aged↗
PubMed1997

[Primary analysis of the situation of hepatitis G virus infection in different groups of people].

In order to investigate the situation of hepatitis G virus (HGV) infection among different groups of people, two self-selected peptides from HGV NS5 were used to develop an indirect ELISA for anti-HGV IgG detection. 1209 sera from different peoples were detected and the positive rate of anti-HGV IgG was (3.8%). Among these groups the group of non A-E hepatitis had the highest anti-HGV positive rate (20.5%), higher than that in the groups of natural people (0.8%) and other hepatitis patients (3.3%), the difference was significant. The anti-HGV IgG positive rate in the group of HC patients 8.0% was higher than that in other hepatitis A-E patients, the positive rate (8.0%) in paid donors was higher than that in voluntary donors (0%), and that in groups with venereal diseases and HIV infection were 3.6% and 8.0%, respectively. The results suggested that there has higher rate of HGV infection in our country; HGV is the important factor causing non A-E, the paid donors is the dangerous group, they should be strictly screened, and the people with transfusion have higher rate of HGV infection. Since there is different rate of HGV infection in different human population so it is important to study further the epidemiological characteristics of HGV for its prevention.

China↗
PubMed1997

[The detection of human immunodeficiency virus type 1/2 antibody using synthetic peptides].

Four peptides of human immunodeficiency virus (HIV) located in the regions of gp41, gp120, p24 of HIV-1 and gp36 of HIV-2 have been synthesized according to the published amino acid sequences and the positions of antigenetic determinants of viruses by a solid-phase method. An indirect ELISA for detecting antibody against HIV 1/2 was established using these synthetic peptides as the coating antigens. We detected 41 control sera provided by National Institute for the Control of Pharmaceutical and Biological Products. The results indicated that the general coincident rate were 100%, the variant coefficient was less than 10%. A comparison of our reagent with Huayi, Pasteur and Jinhao reagents in detection of 90 positive sera and 140 normal sera for HIV-1/2 showed that the coincident rate was 100% with Pasteur and Jinhao, 99.57% with Huayi. All of 186 sera from patients with other diseases were negative. The reagent are stable at 37 degrees C for 4 days. The results indicated that our reagent is highly specific, sensitive and stable, it can be used for detection of HIV-1/2 infections.

Antibodies, Viral↗
PubMed1997

[In vitro effects of hematopoietic growth factors on CD34+ cell from patients with myelodysplastic syndromes].

OBJECTIVE: To investigate the role of recombinant human hematopoietic growth factors (HGFs) in the treatment of myelodysplastic syndromes (MDS) patients. METHODS: CD34+ cells from 16 MDS patients were purified up to 96% approximately 99% by means of a immunomagnetic beads sorting system. The effects of individual and combination of HGFs on the proliferation and differentiation of the CD34+ cells were studied in semi -solid cultures. RESULTS: CD34+ cells were impaired and none of the individual HGF (GM-CSF, IL-3, SCF) could effectively support their proliferation and differentiation. rh-SCF combined with GM-CSF, IL-3 or Epo could partly increase the colony forming capacity of MDS hematopoietic progenitor, however, an increase of undifferentiated blast cells colonies occurred in some high-risk MDS patients at the same time. CONCLUSION: Proper combination of HGFs was essential for improving hematopoiesis in MDS patients.

Animals↗
PubMed1997

Protein engineering on subtilisin E.

Protein engineering was carried out by site-directed and random mutagenesis on subtilisin E gene. Four mutants were obtained. They are M222A; M222A, N118S; M222A, N118S, Q103R; and M222A, N118S, Q103R, D60N. The mutant genes were recombined in pBE-2, an E. coli-B. subtilis shuttle vector, and transformed into B. subtilis DB104, an alkaline and neutral proteinase deficient strain. The subtilisin E mutations obtained from their gene expressions were purified. The properties of these mutants showed that the M222A mutation made the enzyme resistant to oxidation, N118S mutation increased the thermal stability, while Q103R and D60N mutations enhanced the specific activity of the enzyme but decreased the thermal stability and, in particular, D60N mutation caused the enzyme to be very unstable. The IEF-PAGE showed that the wild type and M222A mutant had the same pI of 8.92, while those of double mutant, triple mutant, and quadruple mutant were 8.88, 9.10, and 9.17, respectively. The optimum pH range was 7.5-9.5 for suc-AAPF-pNA substrate and was 10-12 for casein substrate.

Catalysis↗
PubMed1997

A self-assembled antibody electrode for HT29 tumour cells.

The present paper describes a self-assembled monoclonal-antibody immunosensor for HT29 tumour cells. This immunosensor is composed of two parts. One is a three-electrode system and the other is a layer of anti-(human colonic tumour) monoclonal antibody DF-I, which self-assembled on to the gold electrode. Two kinds of cells, HT29 tumour cells and normal fibroblast cells, were compared using the antibody electrode. The result was the same as that obtained by using immune luminescence. The HT29 cells can be captured specifically by the assembled anti-HT29 monoclonal-antibody electrode and can be measured by an electrochemical method.

Antibodies, Monoclonal↗
PubMed1997

[Nursing study of social disability in schizophrenics].

To explore the factors of effect on social disability of schizophrenics and nursing to the schizophrenics, 100 discharged schizophrenics were investigated and studied, with Social Disability Screening Schedule (SDSS) and questionnaire of factors of effect on social disability. The result showed SDSS scores of 53% schizophrenics were over or equal 2, and the social disability were significant positive correlated with patient's age, treatment effect, education, psychosocial factors, compliance, recovery confidence, working chance, and family monthly average income. The result suggested that nursing of three aspect, including mental care, family education, and social support, was benefit for reducing the social disability of schizophrenics.

Adult↗
PubMed1997

[The relationship between multi-drug resistance gene expression and drug resistance of ovarian carcinoma].

OBJECTIVE: To study the relationship between multi-drug-resistance (MDR1) gene expression and the drug resistance of ovarian carcinoma and the reversing potency of drug-resistance modifying agent--cyclosporin A (CsA). METHODS: Tumor-bearing mice of ovarian carcinoma cell (OVCA3) were divided randomly into three groups: control group, adriamycin (ADM) group and ADM +CsA group. The tumor growth rate and the survival rate of mice were investigated and compared among the groups. 32 frozen specimens of ovarian carcinoma tissue from patients were examined for the expression of MDR1 gene by means of RT-PCR. RESULT: Ovarian carcinoma cells with positive MDR1 gene expression showed cross drug-resistance to ADM, daunorubicin (DNR), vincristine (VCR) and etoposide (VP-16), the value of inhibiting concentration (IC50) is 4.1-15.5 times of that of the cells with negative MDR1 gene expression. To tumor-bearing mice, there was significant difference in tumor growth rate between mice given combined therapy of CsA + ADM and those given ADM only (P<0.01) Of the 32 frozen specimens of ovarian carcinoma tissue, there was no confirmed relationship between MDR1 gene expression and the pathologic type or differential grade. The possibility of poor prognosis of patients with positive MDR1, gene expression was 16.07 (1.78-144.7) times of that of patients with negative MDR1 gene expression. CONCLUSION: MDR-related drug can induce the overexpression of MDR1 gene and result in the appearance of the multidrug resistance phenomenon. CsA can partially reverse the multidrug resistance of ovarian carcinoma cells both in vitro and in vivo. Detection of MDR1 gene expression in patients of ovarian carcinoma could be used as an index to predict the prognosis of the patients.

Animals↗
PubMed1997

[Dynamic changes in cytokines in wound exudates from superficial II degree burns in rats].

We take rats as models to study the dynamic changes in cytokines in wound exudate at different time phases post-burn. 120 SD rats were divided into two groups: group 1 with subcutanous implantation of sponges only (S), and group 2 rats were inflicted 10% superficial II degrees burns of their total body surface immediatly after the implantation (Sb). The activities of IL-1, IL-6 and TNF alpha in wound exudates within sponges were measured at 6 h, 1 d, 3 d, 7 d, 10 d and 14 d after the injuries. The changes in activity of these cytokines in both groups showed somewhat the same type of fluctuations, i.e., temporarly ebb and flow in the early phases, and 72 hs later showing a steady increase. The activity of IL-6 reached the peak level in 6 hs while IL-1 and TNF alpha in 24 hs. Probably the early peak levels were produced by local cells responding to the injuries. At each peak level, there was an apparent difference between group S and group Sb (p < 0.01). In the early phases, the levels were S > Sb, and later, the reverse. In group S there was a positive correlation between IL-1 and IL-6, whereas in Sb only 6 h's exudate showed a weak positive correlation. We think the cause of the early differences was: 1. less number of cytokine secreting cells in Sb due to severer injury to local tissues, and 2. increased capillary permeability releasing cytokines from local tissues to the surroundings. The late differences suggest that repair was more complicated and time-consuming in Sb.

Animals↗
PubMed1997

[Studies on applied anatomy of canine larynx].

In order to carry out an experiment of canine laryngeal transplantation, neck dissections were performed in 10 canines in this study. Canine larynx-correlated neck muscles and the main arteries which supply the larynx and drainage veins were observed. The diameter of the vessel was measured and the major passages of the blood circulation were analysed. The arteries and veins, which should be anastomosed, were discussed. The results showed that the bilated cranial thyroid arteries arising from the common carotid and the external jugular veins (through the hyoid venous arch) were the major passages of blood circulation of the larynx. This finding suggested that the unilateral cranial thyroid artery can supply sufficient blood for the survival of a transplantated larynx.

Animals↗
PubMed1997

[Polymorphism and pologenetic affinities of genotype in pathogenic yeast].

The classification of pathogenic yeast, which is one of the most common reasons of opportunistic infection in human body, will be useful for the epidemiological survey and clinical works. The genotypic polymorphism of intergenus, interspecies and intraspecies in 48 isolates, including Candida, Cryptococcus, Torulopsis, Trichosporon, Saccaromyces had been administered carefully with patterns amplified by RAPD (Randomly amplified polymorphic DNA) in 53 primers. The pologenetic affinities had been evaluated by similarity coefficients obtained from these profiles. The results indicated that there are significant difference among intergenus, interspecies and intraspecies in Candida and related yeast. The similarity coefficients among Candida and Crytococcus, Trichosporon were maintained about 80%. The similarity coefficients among interspecies of Candida ranged from 82%-87%, and ones of intraspecies of different Candida species were more than 90%. The genotypic typing of species except C. guilliermondii seems to be related to morphological classification.

Candida↗
PubMed1996

Hairpin loops consisting of single adenine residues closed by sheared A.A and G.G pairs formed by the DNA triplets AAA and GAG: solution structure of the d(GTACAAAGTAC) hairpin.

The DNA undecamers GTACAAAGTAC (AAA 11-mer) and GTACGAGGTAC (GAG 11-mer) have been studied in solution by high-resolution NMR spectroscopy. Both duplexes form stable hairpins containing single deoxyadenosine loops and stems containing five base-pairs that are closed at the loop end by sheared AxA and GxC pairs, respectively. These molecules thus contain new AAA and GAG loop turn motifs. All protons, including the chiral H5'/H5" protons of the loop residues, were assigned using NOESY, DQF-COSY and heteronuclear 1H-31P COSY experiments. The backbone torsion angles were constrained using experimental data from NOE crosspeaks, three-bond 1H-1H coupling constants and four-bond 1H-31P coupling constants and four-bond 1H-31P coupling constants. The AAA and GAG 11-mers form similar structures in solution. The detailed structure of the AAA 11-mer was determined by the combined use of NMR, distance geometry and energy minimization methods. This structure exhibits good stacking of the loop adenosine base on the closing 5Ax7A sheared pair, with the 6A base stacking on the 5A base and the 6A deoxyribose stacking with the 7A base. All sugars in the AAA 11-mer hairpin adopt the typical DNA C2'-endo conformation and a sharp backbone turn occurs between residues 6A and 7A. This loop turn is brought about mainly by a change in the backbone phosphate torsion angles from zeta(g-) alpha(g-) to zeta(g+) alphat(g+) at the turn. The gamma torsion angle of residue 7A in the closing sheared pair also changes from gauche+ to trans. In Pu1NPu2 loop turns of the GCA, AAA and GAG types, the chemical shift of the H4' proton of the loop deoxyribose depends on the nature of Pu2; this reflects the stacking of the loop sugar on the Pu2 base and the different ring current effects of A or G in this position.

Adenine↗
PubMed1996

Pattern of liver, kidney, heart, and intestine allograft rejection in different mouse strain combinations.

With advances in microsurgery and molecular biology, the mouse model for organ transplantation has become increasingly popular. However, knowledge about these models is limited, as only a small number of centers have experience with murine models. In this study, we compared the rejection pattern after liver, kidney, heart, and small bowel transplantation in the three different mouse strain combinations: (1) C57BL/6 (H2b)-->BALB/c (H2d), (2) BALB/c (H2d)-->CBA (H2k), and (3) C57BL/6-->C3H/HeN (H2k). Our study demonstrated that mouse allograft survival varies depending on the organ graft and on the donor-recipient strain combinations. The majority of liver allografts were spontaneously accepted despite complete MHC disparity. A mixed pattern of acute rejection and acceptance occurred in kidney recipients depending on the donor-recipient strain combination. All the heart grafts developed rejection and all the intestinal grafts were rapidly rejected with no spontaneous acceptance. The criteria for rejection, the potential applications, and the limitations of each model are discussed. The models described in this article provide a number of useful choices for organ transplantation research.

Animals↗
PubMed1996

A single G-to-C change causes human centromere TGGAA repeats to fold back into hairpins.

Recently, we established that satellite III (TGGAA)n tandem repeats, which occur at the centromeres of human chromosomes, pair with themselves to form an unusual "self-complementary" antiparallel duplex containing (GGA)2 motifs in which two unpaired guanines from opposite strands intercalate between sheared G.A base pairs. In separate studies, we have also established that the GCA triplet does not form bimolecular (GCA)2 motifs but instead promotes the formation of hairpins containing a GCA-turn motif in which the loop contains a single cytidine closed by a sheared G.A pair. Since TGCAA is the most frequent variant of TGGAA found in satellite III repeats, we reasoned that the potential of this variant to form GCA-turn miniloop fold-back structures might be an important factor in modulating the local structure in natural (TGGAA)n repeats. We report here the NMR-derived solution structure of the heptadecadeoxynucleotide (G)TGGAATGCAATGGAA(C) in which a central TGCAA pentamer is flanked by two TGGAA pentamers. This 17-mer forms a rather unusual and very stable hairpin structure containing eight base pairs in the stem, only four of which are Watson-Crick pairs, and a loop consisting of a single cytidine residue. The stem contains a (GGA)2 motif with intercalative 14G/4G stacking between two sheared G.A base pairs; the loop end of the stem consists of a sheared 8G.10A closing pair with the cytosine base of the 9C loop stacked on 8G. The remarkable stability of this unusual hairpin structure (Tm = 63 degrees C) suggests that it probably plays an important role in modulating the folding of satellite III (TGGAA)n repeats at the centromere.

Centromere↗
PubMed1996

Induction of apoptosis by anti-CD3 epsilon F(ab')2 in antigen receptor transgenic murine T cells activated by specific peptide.

Peripheral T cell tolerance can be achieved through deletion of mature CD4+ cells activated by high dose Ag. We tested whether apoptosis of peripheral CD4+ cells could be induced by a stimulatory dose of Ag plus a soluble ligand to the nonpolymorphic epsilon-chain of the TCR-associated CD3 complex. CD4+ T cells from the DO10 mouse express a transgenic TCR-alphabeta specific for OVA peptide 323-339 presented by I-A(d). OVA alone induced clonal activation and expansion of peripheral CD4+/TCR transgene+ cells. Simultaneous exposure to specific Ag plus soluble anti-CD3 Fos, a nonmitogenic anti-CD3epsilon genetically engineered F(ab')2-like Ab, blocked expansion and induced death of CD4+/TCR transgene+ cells, but not CD4+/TCR transgene- T cells. In contrast, a mitogenic anti-CD3epsilon Ab induced polyclonal activation and nonselective T cell death. Sequential stimulation by Ag followed by anti-CD3 Fos also induced death of TCR transgene+ cells, whereas stimulation by anti-CD3 Fos followed by Ag did not affect cell viability or function. Anti-CD3 Fos-induced death was associated with DNA fragmentation characteristic of apoptosis, was facilitated by IL-2, and was initiated by stimulation during the S-G2 phases of the cell cycle. Anti-CD3 Fos could induce deletion of Ag-activated T cells by apoptosis in vivo. Thus, a soluble, non-Fc-binding anti-CD3 Ab can induce programmed cell death of Ag-activated peripheral CD4+ T cells by CD3epsilon cross-linking during S or G2. Peripheral T cell deletion by activation-driven apoptosis is under cell cycle control and can be exploited to achieve selective immunosuppression by nonmitogenic anti-CD3epsilon Abs.

Amino Acid Sequence↗