Biomedical subjects

L Ma

Publications and source records attributed to L Ma.

At least 199 records · Page 11Linked to original sources

PubMed2000

[Targeting studies of humanized scFv25 fusing to TNFalpha against hepatocellular carcinoma].

OBJECTIVE: To obtain humanized engineering bifunctional antibody, which has potentialities for clinical application. METHODS: Humanized anti-human hepatocellular carcinoma (HCC) single chain fragment (hscFv25) was linked with human TNF-alpha gene to form anti-HCC bifunctional antibody, then it was subcloned into prokaryotic GST fusion expression vector pGEX 4T-1 and expressed in the host E.coli. Indirect immunofluorescent staining was performed on HCC cell smearing slides in order to evaluate the activity of the purified aim protein, then MTT trial to evaluate the cytotoxicity of hscFv25-TNFalpha to SMMC-7721, finally primary tumor regression trial in nude mice bearing HCC to evaluate the targeting therapeutic value of hscFv25-TNFalpha. RESULTS: The hscFv25-TNFalpha had the similar specificity to parental antibody HAb25 for SMMC-7721 antigen. One hour predisposed MTT trial in control with parental antibody HAb25 affirmed that hscFv25-TNFalpha was cytotoxic to targeted cell SMMC-7721 with the IC(50) to be 7.1 microg/ml. The cytotoxicity can be inhibited by parental antibody HAb25. This indicated that the cytotoxicity of hscFv25-TNFalpha to targeted cell is antibody-mediated selective cytotoxicity. The tumor regression trial to the 3mm HCC xenografts in nude mice showed that hscFv25-TNFalpha had assured targeting cytotoxicity and the efficiency was nearly up to 3/3 (1/3 complete remission, 2/3 partial remission). The cytotoxicity of the hscFv25-TNFalpha was better than that of TNFalpha, whose efficiency was only 2/3 and without complete remission. CONCLUSION: hscFv25-TNFalpha is an anti-HCC bi-functional antibody which has potentialities for clinical application.

Animals↗

PubMed2000

[Expression and characterization of human vascular endothelial growth factor in Pichia pastoris].

OBJECTIVE: To study the expression of human VEGF165 cDNA in Pichia pastoris and to obtain high-level expression of recombinant human VEGP165 (hVEGF165) with good biological activity. METHODS: Amplifying hVEGF165 cDNA by PCR, after confirmed by DNA sequence analysis, the gene was inserted into the Pichia pastoris expression vector pPIC9K containing AOX1 promoter and a secreting signal peptides, the recombinant expression plasmid pPIC9K/VEGF165 was constructed and transformed into KM71. The multiple insert transformants were screened, fermented in flasks and induced by 1% methanol. RESULTS: After 4 days of methanol induction, the expressed hVEGF165 came up to 30% of total proteins in supernatant by SDS-PAGE. The expressed hVEGF165 was further proved having good antigenicity and high specificity by ELISA and Western blot assay, and having good biological activity to stimulate HUVEC proliferation. CONCLUSIONS: High-level expression of secreted hVEGF165 had been successfully achieved in Pichia pastoris expression system.

Endothelial Growth Factors↗

PubMed2000

Mitochondrial gene variation in type 2 diabetes mellitus: detection of a novel mutation associated with maternally inherited diabetes in a Chinese family.

OBJECTIVE: To explore the relationship between type 2 diabetes mellitus and the mutation(s) in mitochondrial DNA. METHODS: According to the previous literature, the fragment of mitochondrial DNA from nucleotide 3153 to 3551, which had shown high frequency of point mutation, was scanned with the technique of polymerase chain reaction--single strand conformation polymorphism (PCR-SSCP) in Chinese normal control, type 2 diabetic population, and 12 families suffered from maternally inherited type 2 diabetes mellitus. Direct sequencing was applied to detect the fragments with abnormal conformation. RESULTS: No special band was found in SSCP electrophoreses in Chinese normal control, and only one subject (No. 81) of diabetic population indicated the abnormality in SSCP study, which was affirmed to be a silent point mutation of T to C at nucleotide 3336 inducing no change in amino acid (ATT-->ATC, Ile). Pedigree 25,001 was the only family that exhibited strongly different SSCP characteristic from the other 11 ones, which was confirmed to be caused by a single point mutation mt3285T-->C/T in the coding region of tRNA(Leu(UUR)) gene by the technique of direct sequencing. CONCLUSIONS: The variation within mt DNA 3153-3551 is not the major cause of type 2 diabetes in Chinese population suffered from this disease in this study. The point mutation T-->C/T at the mitochondrial nucleotide 3285, which was found in pedigree 25,001, is located in the highly conservative region of tRNA(Leu(UUR)) gene. It is strongly suggested that this mutation cause the conversion in the 3-dimentional structure of tRNA(Leu(UUR)), which might disturb the normal translation and lead to the impairment in mitochondrial oxidative phosphorylation characterized by the defects of the polypeptides involved in the respiratory chain. Thus, insulin secretion deficiency and insulin resistance might occur.

Adult↗

PubMed2000

The effects of glucose, insulin and oxidized low density lipoprotein on apoptosis in vascular endothelial cells.

OBJECTIVE: To study the effects of high concentrations of glucose, insulin and oxidized low density lipoprotein (ox-LDL) on apoptosis in cultured bovine aortic endothelial cells (ECs). METHODS: For qualitative determination of EC apoptosis, acridine orange (AO)/ethidium bromide (EB) staining and DNA agarose gels electrophoresis were used. Cellular DNA fragmentation ELISA measured apoptosis by quantitating the fragmentation of 5-bromo-2'-deoxyuridine-labeled DNA. RESULTS: High concentrations of glucose (20 mmol/L, 40 mmol/L), insulin (3000 microU/ml) and ox-LDL (50 micrograms/ml, 100 micrograms/ml) induced concentration- and time-dependent apoptosis in ECs. They had a synergetic effect on EC apoptosis. The combined effect of high concentration of glucose, insulin and ox-LDL was greater than any two of them; the effect of two was greater than one alone. Low concentration of insulin (30 microU/ml) decreased apoptosis in ECs induced by high concentrations of glucose (40 mmol/L), but no similar effect occurred with ox-LDL (100 micrograms/ml). CONCLUSION: High ambient glucose, insulin and ox-LDL can induce excessive apoptosis in cultured ECs, and low ambient insulin can prevent EC apoptosis. Excessive EC apoptosis induced by the separate or synergetic effect of hyperglycemia, hyperinsulinemia and hyperlipidemia may be one of the reasons for loss of endothelial integrity, dysfunction of the vascular endothelium and increased plasma membrane permeability, which are all involved in the development of diabetic macrovascular complications.

Animals↗

PubMed2000

[Expression of mismatch repair gene hMSH2 in human malignant ovarian tumors and its clinical significance].

OBJECTIVES: To study the expression of hMSH2 gene in human malignant ovarian tumor and its relationship to clinicopathological characteristics. METHODS: The expression of hMSH2 gene in 42 patients with malignant ovarian tumor was detected by immunohistochemistry streptomycin peroxidel method using monoclonal antibody to hMSH2 protein. RESULTS: hMSH2 expression was observed in the 26 of 42 malignant ovarian tumors (62%), more frequently present in serous and mucinous adenocarcinoma (80%, 80%) than in endometrioid adenocarcinoma and malignant germinal tumors (1/6, 1/6) (P < 0.05). It was significantly higher in high grade than in low grade (P < 0.05), and the reduced expression of hMSH2 was also significantly more often in lymphnodes metastasized cases. Statistical analysis indicated that hMSH2 expression wasn't related to the stage of the tumors. CONCLUSIONS: These results suggest that the abnormal expression of hMSH2 might be involved in the carcinogenesis process and progression of malignant tumor, and that the loss of the hMSH2 protein expression might be a useful predictor of early diagnosis and prognosis of malignant ovarian tumor.

Base Pair Mismatch↗

PubMed2000

[Dural arterovenous fistula involving cavernous sinus].

OBJECTIVE: To study the pathogenesis and treatment of dural arteriovenous fistulas (DAVFS) involving the cavernous sinus. METHODS: 32 cases were embolized with particle by microcatheterization via endovascular approach and ervation by digital substraction angiography. Of the 32 cases, 14 were embolized by microsoils through superior petrosal sinus approach into the cavernous sinus. RESULTS: In 28 of the 32 cases the fistulas were completely embolized angiographically. The fistulas were partly embolized in 4 of the 32 cases. The carotid artery was compressed for 6 months. One week later, the fistula disappeared angiographically. No fistulas were found during the follow-up for 6 months to 8 years. CONCLUSION: Endovascular treatment of DAVFS involving the cavernous sinus is effective.

Adolescent↗

PubMed2000

[Measurement of gastric emptying with Xianshizi in patients with resected esophageal cancer].

OBJECTIVE: To determine gastric emptying radiological in patients with esophageal cancer and to obtain a similar effect produced by radionuclide study. METHODS: A new product-Xianshizi (XSZ) made of the mixture of barium and silica gel was used quantitatively to evaluate gastric emptying. 17 patients with resected esophageal cancer before and after operation, and 7 healthy volunteers were studied. RESULTS: Preoperative patients had obviously delayed gastric emptying compared with the control group (P < 0.01). Postoperative patients had more delayed gastric emptying compared with themselves (P < 0.05). CONCLUSIONS: Postoperative gastroparesis is related to delayed gastric emptying. The results of this study were identical with those obtained by scintigraphy. Compared with isotope studies, X-ray exam after taking meal composed of XSZ may eventually contribute to detecting delayed gastric emptying quantitatively.

Adult↗

PubMed2000

[Caspase 3 in the cytokines induced acute leukemia cell apoptosis].

OBJECTIVE: To explore the variation and significance of caspase 3 activity in the process of G-CSF and GM-CSF regulated NB4 cell apoptosis. METHODS: Cell morphology, flow cytometry and DNA fragmentation assay were used to demonstrate the apoptosis induced by G-CSF and GM-CSF. Caspase 3 activity was detected by spectrofluorometry, and its inhibition test by AC-DEVD-CHO. RESULTS: G-CSF could induce NB4 cell apoptosis, while GM-CSF could not. Caspase 3 activity was significantly higher in the apoptotic cells than in control cells. The G-CSF induced NB4 cell apoptosis was efficiently inhibited by AC-DEVD-CHO. CONCLUSIONS: G-CSF and GM-CSF exert different effects on the apoptosis of leukemic cells. G-CSF induced apoptosis of leukemic cells through activation of caspase 3.

Apoptosis↗

PubMed2000

[Influence of pravastatin on expression of platelet CD(62P) and CD(41) in patients with hypercholesterolemia in vitro and in vivo].

OBJECTIVE: To study in vitro and in vivo effect of hypercholesterolemia (HC) on expression of platelet CD(62P) and CD(41) and their changes after treatment with pravastatin. METHODS: Twenty patients with HC were given 10 - 20 mg/d pravastatin orally for 4 - 8 weeks. Changes of blood cholesterol and expression of platelet CD(62P) and CD(41) were detected by flow cytometry. RESULTS: After 4 and 8 weeks' treatment, blood cholesterol level and platelet aggregation function decreased. The expression of CD(62P) average fluorescence intensity decreased from 31.8 +/- 7.8 to 27.2 +/- 6.9 and 26.8 +/- 4.9; CD(62P) (%) from (31.3 +/- 9.3)% to (26.4 +/- 7.4)% and (25.3 +/- 9.1)% (P < 0.05); CD(41) from 483.2 +/- 263.9 to 348.1 +/- 192.4 and 306.8 +/- 128.0 (P < 0.05), respectively. Similar results were obtained in vitro study. CONCLUSION: Improvement of platelet function and expressions of CD(62P) and CD(41) in HC patients after prevastatin treatment may be resulted from enhancing arteriosclerosis regression. It suggested from the in vitro result that pravastatin might play a direct effect on platelet function.

Adult↗

PubMed2000

[Detection of soluble endothelial protein C receptor (sEPCR) in patients with CHD, DM and SLE].

OBJECTIVE: To evaluate the clinical significance of plasma soluble endothelial protein C receptor (sEPCR) level in patients with coronary heart disease (CHD), diabetes mellitus (DM) and systemic lupus erythematosus (SLE). METHODS: ELISA of antibody-sandwiched principle was used to detect sEPCR in 34 patients with CHD, 42 with DM-II, 63 with SLE and 20 normal controls (NC). RESULTS: The plasma level of sEPCR in patients with DM was higher than that in NC group (P < 0.05). The sEPCR level in SLE patients with thrombosis and non-thrombosis are higher than that in NC group (P < 0.005 and P < 0.001, respectively). There is no significant difference between the two groups of SLE (P > 0.05), and between the CHD and NC groups. CONCLUSION: sEPCR level increased in DM and SLE, it seems related to the process of inflammatory reaction and damage of endothelial cell.

Adolescent↗

PubMed2000

[Expression of lipofect AMINE mediated human GM-CSF eukaryotic expressing vector in HFCL cells].

OBJECTIVE: To construct an eukaryotic expressing vector-pIRES1neo/hGM-CSF and express it in human bone marrow stromal cell line HFCL. METHODS: Human granulocyte/macrophage colony-stimulating factor cDNA (hGM-CSF cDNA, 751 bp) was inserted into an effective eukaryotic expressing vector-pIRES1neo which contains the human cytomegalovirus (CMV) major immediate early promoter/enhancer and the internal ribosome entry site (IRES) of the encephalomyocarditis virus (ECMV). HFCL cells were transfected with the recombinant vector pIRES1neo/hGM-CSF by liposome-mediated gene transfer method. Integration of hGM-CSF in the genome, transcription of its mRNA and expression of its protein in the transfected HFCL cells were assayed by Southern blot, Northern blot, ELISA and hGM-CSF dependent cell line TF-1. RESULTS: hGM-CSF cDNA was integrated into HFCL genome successfully, hGM-CSF mRNA was transcripted and hGM-CSF protein was expressed of (56.9 +/- 0.7) ng/10(6) cells by ELISA and (6.56 +/- 0.16) x 10(3) U/10(6) cells per day by TF-1 cell assay in the supernatant. CONCLUSION: The recombinant vector is proved to be stably expressed in HFCL cells and the biological activity of hGM-CSF was detectable in the supernatant of the transfected cells.

Blotting, Northern↗

PubMed2000

[The effect of adrenalectomy on morphine dependence behavior of rats with forced-swimming].

In this study, the possible action of stress and glucocorticoids on the drug-seeking behavior was explored in the rats with morphine dependence. Forty rats were assigned into four groups randomly and received different treatments as follows: adrenalectomy; adrenalectomy + hydrocortisone 20 mg/kg S.C.; adrenalectomy + hydrocortisone 40 mg/kg S.C.; saline S.C.; The effect of adrenalectomy and hydrocortisone on morphine conditioned place preference (CPP) in rats with forced-swimming was observed. The results showed: 1. there was no significant difference for the adrenalectomized rats' spending time between the morphine and saline-paired side during the test session (t = 1.84, P > 0.05), but obvious differences of time spent between the morphine and saline-paired side were observed among the other three groups (P < 0.05 or P < 0.01); 2. the time spent in the morphine-paired side of the adrenalectomized group significantly decreased, compared with those of the other three groups, and there was no difference for the time spent in the morphine-paired side among the groups of adrenalectomy + hydrocortisone 20 mg/kg S.C., adrenalectomy + hydrocortisone 40 mg/kg S.C., and saline S.C.. These data suggested that adrenalectomy could decrease the facilitation action of morphine CPP induced by forced swimming in rats, whereas administration with glucocorticoids should reverse this effect.

Adrenalectomy↗

PubMed2000

[Study on the effect of several antioxidants on the stability of oils].

The stability of oils is very important for ensuring the sanitation and quality of oils and the foods containing oils and fats. In this study, BHT, TBHQ and micro-capsule antioxidants (mixed antioxidants) were tested for their properties of antioxidation in oils under different temperatures. The results showed that the mixed antioxidant used in oils was more effective than the single antioxidant, especially under high temperature. It was concluded that microcapsule antioxidant was effective, economical and relatively safe when it was used in oils for frying foods.

Antioxidants↗

PubMed2000

[Effect of estrogen on the expression of c-myc protein of bone in mice].

In order to study the mechanism by which estrogen effects on bone, the effect of estrone on expression of c-myc protein in the epiphyseal plate of fetal mouse long bone was detected by immunohistochemistry procedure in vitro. The result showed that the concentrations of estrone areas of positively staining cells increased significantly in proliferative zone at 10(-9) mol/L, in proliferative zone and resting zone at 10(-8) mol/L, and in resting zone, proliferative zone and hypertrophic zone at 10(-7) mol/L respectively. It was considered that estrogen might enforce endochondral bone formation by enhancing expression of c-myc in long bone.

Animals↗

PubMed2000

[Simultaneous primary palate repair and alveolar bone grafting in unoperated cleft palate patients over 8 years old].

OBJECTIVE: To analyze the applicability and results of simultaneous primary palate repair and alveolar bone grafting in unoperated cleft lip and palate patients over 8 years old. METHODS: A retrospective study was performed in a group of unoperated cleft palate patients who received simultaneous primary palate repair and alveolar bone grafting. Between December 1990 and March 1998, a consecutive of 38 complete unilateral cleft lip and palate patients were treated by the procedures of simultaneous primary cleft palate repair and alveolar bone grafting at the Peking University of Cleft Lip and Palate Treatment Center. All the patients had their lip repaired before they were admitted. The age range was 8 to 24 years, with the average of 14.7 years old. The duration of operation as well as the blood loss during the operation was recorded, and compared with those patients who only received alveolar bone grafting. All the patients have been followed up for at least twelve months, and the results of bone grafting were evaluated according to radiographs. RESULTS: All the operations were successful, and the wound healed well. Compared with simple alveolar bone grafting, simultaneous primary palate repair and alveolar bone grafting prolonged the operation time to an average of 37 minutes. The procedure of simultaneous primary palate repair and alveolar bone grafting did not prolong the operating time compared with simple alveolar bone grafting and no blood transfusion due to bone grafting was needed. All the wounds both in the grafted area and donor site healed uneventfully. No major complications occurred during or shortly after the operation. The overall clinical successful rate of alveolar bone grafting in this group of patients was 89.5%. CONCLUSION: Simultaneous primary palate repair and alveolar bone grafting are safe and applicable procedure for unoperated cleft palate patients, and this procedure should be performed in those unoperated cleft palate patients above 8 years old.

Adolescent↗

PubMed2000

[Cloning and identification of cytochrome P450 resistance related genes in the mosquito, Culex pipiens pallens].

OBJECTIVE: To inquire into the relationship between cytochrome P450 and deltamethrin resistance. METHODS: 24 new cDNA sequences encoding cytochrome P450 were amplified respectively from deltamethrin-susceptible and -resistant strains of Culex pipiens pallens with a pair of degenerate primers according to the conservative amino acid sequences of CYP4 in insects by RT-PCR and the Direct Cloning Method, and then were identified by cDNA chip and reverse Northern. RESULTS: 112 positive clones were obtained, of which 24 were shown to be new sequences encoded for cytochrome P450. They have been lodged in GenBank and were appraised by the Nomenclature Committee of Cytochrome P450, belonging to the subfamily CYP4C, CYP4D, CYP4H and CYP4J in CYP4 family. The hybrid signal values of 6 P450 sequences (NYDS3, NYDS5, NYDR6, NYDR9, NYDR15 and NYDR17) were 3.1-9.7 times higher in the resistance probe than in the susceptible probe, and NYDR17 only reacted with the resistance probe. The result of reverse Northern in NYDR15 was similar to that of cDNA chip. CONCLUSION: CYP4 is related to deltamethrin resistance and the specific expression caused by point mutation of cytochrome P450 gene may exist in deltamethrin-resistant Cx. pipiens pallens.

Animals↗

PubMed2000

[Gene cloning and characterization of mitochondria-related protein of Schistosoma japonicum].

OBJECTIVE: To subclone and characterize a cDNA clone coding for Schistosoma japonicum (S.j.) mitochondria-related protein. METHODS: The open reading frame of the fragment(Sj338/24) obtained from an adult worm cDNA library of S.j. was analysed, at the upstream and downstream of the open reading frame(ORF) the primers A and B were designed, respectively, and the cDNA fragment was used as PCR template. The Sj338 gene fragment obtained was amplified by PCR method and then subcloned into pGEM-T vector for sequencing. The gene sequence was analyzed and the target fragment was restrictedly digested and subcloned into expression vector pGEX-6P-1. The expressed recombinant protein was purified and characterized. RESULTS: The cloned Sj338 gene was demonstrated to be 487 bp long containing one 459 bp ORF, encoding a protein with a molecular weight of 17 kDa. The nucleotide sequence of the cloned gene Sj338 had higher homology with those genes coding for mitochondrial outer membrane protein of Homo sapiens and Rattus norvegicus. The recombinant construct of pGEX-6P-1/Sj338 could be expressed efficiently and the antigenicity of its product rSj338 has been demonstrated by Western blotting. CONCLUSION: Sj338 may be the gene coding for S.j. mitochondria-related protein and the recombinant protein may be used as a new vaccine candidate.

Amino Acid Sequence↗

PubMed2000

[Use of Hopkins rod-lens coupled with grasping forceps sheaths for extraction of tracheobronchial foreign bodies].

OBJECTIVE: To study the clinical application of Hopkins rod-lens coupled with gasping forceps sheaths in the extraction of tracheobronchial foreign bodies. METHODS: Sixty-two patients with tracheobronchial foreign bodies were operated on with Hopkins rod-lens coupled with grasping forceps sheaths under direct telescopic view or TV watching. High frequency jet ventilation was used and BPs ECGs SaO2 were monitored in all cases. RESULTS: Sixty-two patients were all successfully operated on. The extraction was primarily successful in 90% of the cases; and secondarily successful in 7% of the cases. No death and serious complication occurred. CONCLUSION: Compared with conventional bronchoscopic foreign body extraction, this new instrument and technique make it possible for the operator to clamp and extract foreign body under direct telescopic view or TV watching. It has increased the accuracy and safety of bronchoscopic extraction of tracheobronchial foreign bodies.

Adolescent↗