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Biomedical subjects

L Zhang

Publications and source records attributed to L Zhang.

At least 541 records · Page 30Linked to original sources
PubMed2001

[Hepatocyte targeted DNA carrier L-PEI: the lactosylated polyethyleneimine and transfection in vitro].

BACKGROUND: To develop a hepatocyte targeted DNA carrier for expression of IFN or delivery of antiviral antisense neucleic acid into hapatocytes. METHODS: The hepatocyte targeted lactosylated polyethleneimine (L-PEI) was prepared through reductive amination of PEI with lactose. The in vitro transfection experiment was conducted and the stability of the DNA complex in rat serum was evaluated. RESULTS: L-PEI can effectively deliver luciferase gene into the galactose receptor positive Huh-7 cells. The transfection can be specifically inhibited by the synthesized ligand-lactosaminated BSA. The complex of DNA/L-PEI is stable in rat serum with only little degradation observed after 30 minutes, while free DNA was destroyed completely. CONCLUSIONS: L-PEI can be used as an specific and efficient DNA carrier.

Animals↗
PubMed2001

[Gigantism with low serum level of growth hormone: a case report].

Gigantism with low or normal basal concentrations of growth hormone (GH) is a rare condition, possibly due to abnormal GH secretory patterns, enhanced tissue sensitivity to GH, or the existence of an unidentified growth promoting factor. Here we report an 11 year-old female case of gigantism with a normal pituitary gland. Her height was 181 cm, body weight 77 kg, and bone age 11.1 years. Her basal serum GH levels were lower than 1 ng/ml. The levels of T3, T4, FT3, FT4, TSH, E2, LH, FSH, PRL, PTC and ACTH were normal. Serum GH response to insulin-induced hypoglycemia or arginine stimulation tests was blunted. In this case, non-pulsatile GH secretion and enhanced tissue sensitivity to GH may induce hypersecretion of IGF-1 and the existence of an unidentified growth promoting factor or biologically active anti-GH receptor antibodies may cause clinical gigantism.

Child↗
PubMed2001

[Recent progress of study on single nucleotide polymorphisms].

Single nucleotide polymorphisms (SNPs) is a new genetic marker system following RFLP and microsatellite polymorphism. It has been shown to have the characteristics of high-density, inheritance stability and facilitation in analysis automation. SNPs can be detected by electrophoresis, endonuclease-cleavage, PCR and sequencing, and can be used extensively in gene mapping, disease-correlativity analysis, population genetics and drug research.

Chromosome Mapping↗
PubMed2001

[A study of genetic polymorphism of the STR locus D2S441 in Chinese Han population in Chengdu].

Using PCR and PAG, followed by silver staining, the tetrameric STR D2S441 locus was studied in 260 unrelated Chinese individuals living in Chengdu. 9 alleles and 26 genotypes were observed. The range of fragment size was 131 bp to 155 bp. The genotype distribution of D2S441 locus in Han population was in accordance with Hardy-Weinberg equilibrium. Family survey confirmed Mendelian inheritance of alleles. The discriminating power (Dp), observed heterozygosity (H), polymorphism information content (PIC) and power of exclusion (PE) were 0.9084, 0.7885, 0.7390 and 0.5778 respectively. The results demonstrated that this locus was highly polymorphic and could be used for forensic identification and paternity testing.

Alleles↗
PubMed2001

[Study on the construction of standard D1S549 allelic ladder via molecular cloning and its genetic polymorphism in Chinese three populations].

OBJECTIVE: To resolve the problem of the accuracy and standardization of STR-PCR typing in forensic practice, we have designed a new method to produce standard D1S549 allelic ladder. METHODS: Eight different PCR amplified D1S549 allelic fragments were isolated from the gel, eluted into the distilled water and re-amplified by PCR. The purified allelic fragments were then blunt-end subcloned individually into the pUC plasmid vectors and transfected into competent E. coli DH5 alpha cells. RESULTS: The sequencing results confirmed that the size and the construe of the inserts were correct. The recombinant plasmids DNA with 8 inserts were then used as templates for re-amplification to generate D1S549 standard ladder, with which the genetic polymorphisms of D1S549 locus in Chinese Han population in chengdu, Hui population in Gansu and Wei population in Xinjiang were studied. CONCLUSION: The results showed that the standard ladder made via this method is excellent, and D1S549 locus is robust for genetic research and forensic application.

Alleles↗
PubMed2001

[The effect of ketamine on the expression of HSP70 induced by endotoxin in liver of rat].

OBJECTIVE: To observe the effect of ketamine on the expression of heat shock proteins (HSP70) in liver of rat with septic shock. METHODS: Sixty-four rats were randomly allocated to control group, endotoxin group and ketamine group. The model of septic shock was used to examine the expression of HSP70 in rat liver and the TNF-alpha level of blood at 2 hours after endotoxin treatment and dying time for endotoxin group rats. The survival rates for the three groups were compared. RESULTS: There was a significant increase in the expression of HSP70 and the level of TNF-alpha in the endotoxin group as compared with those of control group (P < 0.05). A significant increase in the expression of HSP70, a decrease in the level of TNF-alpha and a significantly higher survival rate were seen in ketamine group when compared with those of endotoxin group, respectively. CONCLUSION: Ketamine could increase the expression of HSP70 in rat liver, restrain the release of TNF-alpha caused by endotoxin, and raise the survival rates of rats with septic shock.

Animals↗
PubMed2001

[Clinical studies on sternocleidomastoid myoperiosteal flap for cervical tracheal reconstruction].

OBJECTIVE: To introduce the experience of repairing the defect of cervical trachea wall by using the sternocleidomastoid myoperiosteal flap after the anterior or posterior wall of cervical trachea was invaded by cervical neoplasm. METHOD: Between 1989 to 1998 the sternocleidomastoid myoperiosteal flap was applied in 12 patients with different diseases, among which 3 cases were thyroid carcinoma 5 cases were laryngeal carcinoma, 4 cases were cervical esophageal carcinoma. RESULT: The operation was successful. 12 patients were decannuated and had normal exercise tolerance. The time from reconstruction to decannulation was ranging from 20 days to 6 months. CONCLUSION: The sternocleidomastoid myoperiosteal flap is an ideal transplant for cervical tracheal reconstruction.

Adolescent↗
PubMed2001

[Study of pharyngo-cutaneous fistula after total laryngectomy].

OBJECTIVE: To explore the factors which lead to pharyngo-cutaneous fistula after total laryngectomy. METHOD: A retrospective study of 125 patients who underwent total laryngectomy during a 16-year period was carried out. RESULT: The rate of post-laryngectomy pharyngo-cutaneous fistula is 16.0% (20/125), it appears reduced tendency. With single-factor analysis, the factors effect on the rate of post-laryngectomy pharyngo-cutaneous fistula include clinical tumor stage, tumor types, pre-operative radiotherapy dose, intraoperative blood transfusion, operative duration. With all variable logistic model analysis, the factors effect on the rate of pharyngo-cutaneous fistula are clinical tumor stage and pre-operative radiotherapy dose, but pre-operative radiotherapy is very possible to be a risk factor (P = 0.0566). With logistic model stepwise regression analysis, the factors effect on the rate of pharyngo-cutaneous fistula are clinical tumor stage and operative duration. CONCLUSION: Pharyngo-cutaneous fistula appears easily in patients with T3, T4 tumor, and have pre-operative radiotherapy, especially have large dose preradiotherapy. For these high risk patients, the duration of operation should be as short as possible to reduce the rate of post-laryngectomy pharyngo-cutaneous fistula.

Adult↗
PubMed2001

[Detection of S-100 protein in laryngeal carcinoma].

OBJECTIVE: To study the relationship between S-100 protein and prognosis of laryngeal carcinoma. METHOD: S-100 protein was observed by immunohistochemical methods using anti-S-100 protein antibody in 68 laryngeal carcinoma and 21 non-cancer laryngeal tissues. RESULT: The result showed that S-100 protein positive were found 43 (63.24%) in 68 laryngeal carcinoma. S-100 protein positive cells were interspersed among the tumor cells and in the stroma. S-100 protein were rare in non-cancer laryngeal tissues. The five-year survival rate in patients with S-100 protein positive was significantly higher than that in patients with S-100 protein negative. CONCLUSION: Our result indicated that the detection of S-100 protein is of value for the prognostic analysis in patients with laryngeal carcinoma.

Humans↗
PubMed2001

[Measurement of microvessel density in laryngeal carcinoma and its clinical significance].

OBJECTIVE: To determine the microvessel density (MVD) in laryngeal carcinoma and its clinical significance. METHOD: Thirty-eight tumor specimens were selected from laryngeal cancer patients from January, 1994 to March, 1996. Histological sections of the tumors were stained immunohistochemically for factor VIII. Using light microscopy, we counted microvessels per 400 x field in the most active areas of tumor angiogenesis. RESULT: 1. The tumor blood vessels, composed of only one layer of endothelium were mainly distributed heterogeneously in the interstitial tissue of laryngeal carcinoma with irregular lumen, poorly developed structure. 2. The MVD in the cancer tissues were statistically higher than that in peritumoral tissues (P < 0.01). 3. The MVD in the cancer tissues in group of patients with metastasis to cervical lymphonodes were statistically higher than in group without metastasis (P < 0.01), the MVD in the cancer tissues in group of advanced cases (III, IV stages) were statistically higher than that in group of early cases (I, II stages, P < 0.01). 4. There was no statistically difference in MVD in the cancer tissue between supraglottic and glottic laryngeal carcinoma patients (P > 0.05). 5. There was no statistically difference in MVD in the cancer tissue among the G1, G2 and G3 group (P > 0.05). CONCLUSION: The laryngeal cancer blood vessels have some characteristics that don't appear in normal vessels. It is suggested that tumor angiogenesis can promote tumor growth and metastasis and MVD may be a new prognostic indicator of laryngeal carcinoma.

Adult↗
PubMed2001

[Simultaneous determination of chlorpheniramine, paracetamol and pseudo-ephedrine hydrochloride in composite tablets by high performance liquid chromatography].

An HPLC method is described for the determination of chlorpheniramine, paracetamol and pseudoephedrine hydrochloride simultaneously in Nuonuo composite tablets. Chromatographic conditions were: column, YWG-C18 column (150 mm x 4.0 mm i.d., 10 microns); mobile phase, 25% methanol(0.05 mol/L sodium dihydrogen phosphate); flow rate, 1.0 mL/min; detection wavelength, 205 nm; injection volume, 20 microL. The detection limits of chlorpheniramine, paracetamol and pseudo-ephedrine hydrochloride were 1.16 mg/L, 0.15 mg/L and 1.82 mg/L respectively and the corresponding average recoveries were 98.35% (n = 5, RSD = 1.60%), 101.16% (n = 5, RSD = 1.50%) and 98.50% (n = 5, RSD = 1.59%) respectively. The proposed method is simple, rapid and accurate and has been satisfactorily used for the quantitative analysis of real samples.

Acetaminophen↗
PubMed2001

[The infiltration and activation stage of eosinophils in nasal polyps].

OBJECTIVE: To assess the infiltration and activation of eosinophils in nasal polyps. METHOD: Nasal polyps from sixteen patients were investigated. The samples were stained with Chromotrope 2R histochemical and ABC immunohistochemical methods. RESULT: The majority of eosinophils in nasal polyps were activated, and there were no significant differences in the numbers of total eosinophils (Chromotrope 2R positive cells) and activated eosinophils (EG2 positive cells) between allergic and nonallergic patients. CONCLUSION: Eosinophilia is a prominent histologic feature of nasal polyps which indicates that the activated eosinophils may play vital role in the pathogenesis of nasal polyps.

Adult↗
PubMed2001

[Research of drug resistance and detection of methicillin-resistant Staphylococcus aureus in chronic maxillary sinusitis].

OBJECTIVE: To investigate the detection method of methicillin-resistant staphylococcus aureus (MRSA) in chronic maxillary sinusitis and the situation of drug resistance to some common antibiotics. METHOD: Using multiplex polymerase chain reaction technique to detect the drug resistant gene (mecA) of MRSA and specific gene (femA) of staphylococcus aureus at the same time. Drug resistant tests were performed with disk diffusion (K-B) method. RESULT: femA is a specific gene of staphylococcus aureus, the detective ratio of mecA in MRSA is 96.2% (51/53). Vancomycin is the only antibiotic which is sensitive to MRSA, while others are not. CONCLUSION: MRSA can be rapidly and specifically identified with multiplex PCR. There are drug resistance to many antibiotic drugs for MRSA.

Adolescent↗
PubMed2001

VEGF induced hyperpermeability in bovine aortic endothelial cell and inhibitory effect of salvianolic acid B.

AIM: To examine the effect of recombinant human vascular endothelial growth factor (VEGF) on the low density lipoprotein (LDL) permeability of bovine aortic endothelial cells (BAEC) and the inhibitory effect of salvianolic acid B in vitro. METHODS: The confluence BAEC monolayers were cultured with normal medium and with medium containing VEGF or salvianolic acid B at various concentrations and for various time periods. The iodine labeled LDL flux across the monolayers was then performed, and radioactivity was measured by SN-695 automatic liquid scintillation counter. RESULTS: Addition of purified human recombinant VEGF to the BAEC monolayers could significantly increase the permeability of the monolayer to 125I-LDL (P < 0.01). The permeability-increasing activity of VEGF on the BAEC monolayers was both dose and time dependent. Salvianolic acid B could markedly inhibit the VEGF-induced hyperpermeability in BAECs (P < 0.01). CONCLUSION: VEGF plays a role in the formation and development of atherosclerosis, and salvianolic acid B has inhibitory effect on VEGF-induced hyperpermeability in BAEC.

Animals↗
PubMed2001

[Studies on ABA-induced H2O2 in Vicia guard cells by means of confocal laser scanning microscopy].

The methods of confocal laser scanning microscopy (CLSM) and microinjection were used to study ABA-induced H2O2 in guard cells (Vicia faba), which were labeled with H2O2 specific probe-2, 7-dichlorofluorescin diacetate(H2DCFDA). The results indicated 100 U/mL catalase (CAT) could inhibit partly stomatal closure induced by ABA. 10(-3) mmol/L ABA could significantly induce H2O2 production in chloroplast in guard cells of Vicia faba following microinjection, and 100 U/mL CAT could partly abolish the effects following simultaneous microinjection of ABA and CAT. These suggest that H2O2 is possibly involved in ABA signaling leading to stomatal closure.

Abscisic Acid↗
PubMed2001

[Use transposon and parDE through in vivo cloning to promote the genetic stability of plasmid pCPP430].

Plasmid pCPP430 carrying the hrp gene cluster after transformated into 308R (Pantoea agglomerans) can cause the hypersensitive response, and simultaneously induce the plant resistance to disease. It was genetically unstable in P. agglomerans. 0.8 kb parDE region of the broad-host range plasmid RK2 is responsible for plasmid partition. It can mediate plasmid maitenance of many kinds in Rhizobium meliloti, and also can promote the genetic stability of recombinant plasmid in the biocontrol bacteria P. agglomerans. In this paper, we cloned parDE into pCPP430 in vivo through transposition to promote its genetic stability. parDE was amplified by PCR, inserted into pGEM-T vector and cut out and religated to NotI-cut transposon vector pUT/mini-Tn5 Km to get a parDE containing mini-Tn5, pTnp. After conjugation between S17-1/lambda pir (pTnp) and 308R (pCPP430), parDE was cloned in vivo into plasmid pCPP430 to obtain pRTnp. It was demonstrated that the insertion of parDE in pCPP430 increased significantly the plasmid's stability in P. agglomerans.

Bacterial Outer Membrane Proteins↗
PubMed2001

[Expression of the artificial cecropin CMIV-like gene of Chinese silkworm Bombyx mori in Laphygma exigua larvae].

The synthesized CMIV-like Gene was linked with the signal peptide gene of nature silkworm antibacterial peptide and was inserted into baculovirus expression vector pFastBac 1, construcing a recombinant transposing vector. The vector was transformed into DH10Bac competent E. coli cells. The recombinant Bacmid was obtained. The recombinant Bacmid was transfected into sf21 cells to get the recombinant virus. Laphygma exigua larvae were infected with the recombinant virus to express the antibacterial peptide. The hemolymph were tested to have antibacterial activity. The active antibacterial peptide was purified by acid polyacrylamide electrophoresis. The specific expression of mRNA of CMIV-like Gene was tested using Northern blotting.

Animals↗