Search PubMed⌕ Search

Biomedical subjects

S Song

Publications and source records attributed to S Song.

At least 199 records · Page 11Linked to original sources
PubMed1996

Generation of high-titer defective HSV-1 vectors using an IE 2 deletion mutant and quantitative study of expression in cultured cortical cells.

Vectors based on herpes simplex virus type 1 (HSV-1) show promise for gene transfer into mammalian cells because of their wide host range, efficient infection and ability to deliver genes to nondividing cells. Defective HSV-1 vectors, or amplicons, are plasmid vectors which are unable to propagate on their own but contain specific HSV-1 sequences that, in the presence of helper virus, support DNA replication and subsequent packaging into virus particles. We compared three replication-incompetent HSV-1 mutants (KOS strain 5dl1.2, strain 17 D30EBA, KOS strain d120) as the helper virus for packaging the prototype defective HSV-1 vector, pHSVlac, which uses the HSV-1 immediate-early (1E) 4/5 promoter to regulate expression of the Escherichia coli lacZ gene. Use of 5dl1.2, which contains a deletion in the IE 2 gene, consistently produced virus stocks that contained a high level of vector, undetectable levels of wild-type HSV-1 and a ratio of vector to helper greater than 1. Virus stocks prepared using 5dl1.2 were superior to those prepared using helper viruses that harbor a deletion in the IE 3 gene, either D30EBA or dl20, and supported more efficient gene transfer than possible with previously published procedures. Lactate dehydrogenase efflux assays in rat cortical cultures showed that 5dl1.2 was no more cytotoxic than either D30EBA or dl20, despite the expression of more viral genes. Rat cortical cultures infected with pHSVlac packaged with either 5dl1.2 or D30EBA were used to quantify the stability of vector expression. Our results show a decrease in the number of cells with detectable levels of beta-galactosidase to 30% of peak levels after one week, irrespective of the helper virus used. However, simultaneous superinfection with 5dl1.2, but not with either D30EBA or dl20, produced a transient increase in the number of cells expressing beta-galactosidase. Superinfection with 5dl1.2 at 9 days after gene transfer increased the number of cells expressing detectable beta-galactosidase back to peak levels, most probably because of reactivation of the IE 4/5 promoter in pHSVlac. These results thus provide the first quantitative demonstration of long-term persistence of defective HSV-1 vectors in neurons.

3T3 Cells↗
PubMed1996

[Investigation of urinary fibrinopeptide A level in pregnancy induced hypertension and its clinical significance].

OBJECTIVE: To investigate the changes of urinary fibrinopeptide A (FPA) level in pregnancy induced hypertension (PIH) and its clinical significance. METHODS: High performance liquid chromatography (HPLC) was employed in determination. Urinary FPA was measured in 96 cases of normal pregnancy and 49 cases with PIH. RESULTS: The urinary FPA levels in mild and moderate PIH groups were significantly higher than that in normal pregnancy (71.65 +/- 18.53 micrograms/L vs 40.17 +/- 20.26 micrograms/L, P < 0.01). The levels of urinary FPA in patients with preeclampsia increased significantly (146.65 +/- 32.53 micrograms/L) when compared with the mild and moderate PIH groups (P < 0.001). The levels of urinary FPA in patients with eclampsia (422.93 +/- 81.46 micrograms/L) were much higher than that in group of preeclampsia (P < 0.001). CONCLUSIONS: It showed that the assay of urinary FPA might be helpful for earlier diagnosis, classification, treatment and judgement of prognosis in PIH.

Adult↗
PubMed1996

[The PCR amplification, cloning, sequencing, expression in E. coli of gene encoding endoflagella subunit protein (fla B) from Leptospira interrogans serovar lai].

A pair of oligonucleotide primers were designed by ourselves to amplify the endoflagella gene of L. interrogans serovar lai. A fragment about 840 bp was generated with PCR and inserted into plasmid pUC8 after the fragment and pUC8 were digested respectively with Bam HI and Pst I. A recombinant plasmid (designated as pLF1) was obtained. SDS-PAGE analysis indicated that a 33 kd was expressed in E. coli JM103 harboring pLF1 and the expression level of the protein was 11% of total bacterial soluble proteins. Western blot analysis showed that the protein band could be recognized by the antiserum against the endoflagella (Axiall filament) of Leptospira interrogans serovar lai. Nucleotide seguence data showed an open reading frame encoding 282 aminoacids residues, corresponding to a protein of molecular weight 33.6 kd. The G + C content of endoflagella subunit protein gene was 48 mol%. Therefore, the G + C content of the leptospiral fla B Gene is significantly higher than the reported 39 mol% G + C content of leptospiral genome of L.interrogans serovar lai but similar to the G + C of the Treponema pallidum genome. Comparison of the deduced endoflagellar subunit protein (fla B) amino acid sequence with flagellins from other bacteria revealed a high level of identity with the Treponema pallidum fla B proteins. Immunization/protection experiment was performed on the model of BALB/c mice and showed that the survival rate in the group JM103-pLF1 was higher than that in the group JM103-pUC8, but statistically the difference between them was significant (P < 0.05) and pLF1 did not induce significant levels of agglutinating antibodies against L.interrogans serovar lai.

Amino Acid Sequence↗
PubMed1996

[Navelbine as a single agent to treat advanced breast cancers].

From March 1994 to March 1995, 14 cases of refractory advanced breast cancers were treated with Navelbine (NVB). NVB as a single agent was given weekly 40-60mg (24.9mg-33.3 mg/m2), every 2 weeks for one cycle. Six of fourteen cases (42.9%) achieved partial response (PR). The median remission duration of PR patients was 5 months (range 2-10 months). NVB was given 85 times, the main side effects were myalgia and arthralgia (80.0%), phlebitis (57.6%). Sixty-five of eighty five pretreatment WBC counts were below 4.0 x 10(9)/L, and the severity of leukopenia was related to pretreatment WBC level. No patient died of infection.

Adult↗
PubMed1996

[Detection of expression of multidrug resistance gene in breast cancer by RT-PCR].

Using RT-PCR technique, we established a method for measuring expression of mdr-1 gene in breast cancer and the conditions affecting PCR results. Expression of mdr-1 gene was detected in 74 breast cancer samples. The results showed that 34.3%(12/35) untreated primary lesions and 59.0%(23/39) relapsed metastatic lesions had positive expression of mdr-1 gene (P < 0.05). In 32 patients, the overall correlation of mdr-1 gene expression with clinical drug sensitivity was 78.1%. The results validate that RT-PCR assay is highly sensitive, relatively quantitative and reliable for measuring levels of mdr-1 gene expression in clinical samples.

Breast Neoplasms↗
PubMed1996

[Finite element stress analysis of stress distribution endodontic posts at shoulder].

The objective of the present resarch is the comparative stress distribution of various design for post-core at shoulder. The purpose of this study was to analyse the stress distribution and concentration in the dentin of paralled-sided and taped posts by different shoulder designs with finite elements stress analysis method. It was found that stress tended to concentrate under the core shoulder with vertical force. When the force applied from the linqual side. The stress concentrated at the buccal side. The 90 degrees shoulder angles exhibited more even stress distribution than sharp shoulder angles. The analysis revealed that sharp angle should be avoided as occlusal shoulder in clinical practice because this design are less resistant to forces applied on them and are susceptible to fractures in the dentin.

Models, Biological↗
PubMed1996

[Protective effects of chrominum on myocardial damage in rats].

To prove the protective effects of trivalent chromium (Cr3+) on myocardial damage, its ultrastructure and electro-physiological changes were observed in different groups of rats with intraperitoneal injection of normal saline, Cr3+ and selenium, and injection of adriamycin (ADR) by their tail vein. Results of ultrastructural observations showed nuclear margin of myocardial cells was obscure, cytoplasm became coarse and sparse, mitochondria vacuolar, myocardiofibril loose, broken and lytic in the group treated with ADR, myocardiopathic changes reduced and myocardial filaments arranged in good order in that with Cr3+ and selenium. QRS complex, Q-T interval, APD50 and APD90 in electrocardiograph (ECG) prolonged in the group with ADR and selenium, and no changes were observed in that with Cr3+. It suggests Cr3+ and selenium have apparently protective effects on rat's myocardium, and Cr3+ also can reverse the changes in ECG caused by ADR, which is of importance in prevention and treatment of cardiovascular diseases.

Animals↗
PubMed1996

[Research on the recombinant plasmid pDJH2 of L. interrogans serovar lai: sequencing and alignment with other known bacterial Omp sequence].

The Leptospira whole cell vaccine (LWCV) currently used in China is safe and effective, out the immunity following vaccination with two doses of the fluid medium vaccine is of low order. The duration of immunity conferred by this vaccine is rather short, six months or at most one year. Therefore, it is necessary to develop new generation vaccines against Leptospirosis for the developing world. In this paper we report the sequencing of the insert fragment of pDJH2 from genomic DNA of L. interrogans sevovar lai strain 017 and its alignment with other bacterial omp sequences. A genomic library of Leptospira interrogaans serovar lai strain 017 was constructed with the plasmid vector pUC18. A recombinant plasmid designated pJDH2 was screened from the genomic library. Inserted fragment of pDH2 is 1.9 kb by gel electrophoresis. Immunization/protection was studied in BALB/c mice model. The results showed highly significant difference between pDJH2 and pUC18 (control). Inserted fragment of pDJH2 DNA sequencing was performed by Dr Yan Zhengxin (Max-Planck-Institut for Biology. Tubingen, Germany). Insert fragment was cloned into pBluescript II KS-(stratagene) and sequenced by using AB1 (Applied Bio Systems, Model 373A). Two open reading frames of 565 and 662 nucleotides were identified. There were identifiable initiation codons, terminators, Shine-Dalgano ribosome combining site, Pribnow boxes and Sextama boxes within the 2 sequenced regions. Nucleotide sequences were analysed using Gene Work, a suit of computer program developed by Department of Biochemistry St. Jude Children's Research Hospital Memphis. U.S.A. The results of formatted alignment showed the predicted nucleotide sequence of ORF1 of the serovar lai had significant similarity with ORF2 (49.36%). L. kirschneri ompL1 (49.26%), Borrelia burgdoferi omp (48.97%), Treponema phagedenis omp (47.3%); Salmonella typhimurium ompC(46.87%), Yersinia enterocolitica ompH (46.7%), Leptospira borgpeterseni pfap (46.3%), and Serratia marcescens omp (43.3%). The close relationship of the pDJH2 ORF1 and ORF2 nucleotide sequences from Leptospira kirschneri ompL 1 is apparent. Whether the recombinant pDJH2 will prove useful for vaccine development remains to be tested.

Animals↗
PubMed1996

[Subclones of fragment DNA recombinant rpDJH2 of L. interrogans serovar lai strain 017 and it's expression of high level in E. coli].

Fragment of 1.9 kb recombinant DNA of pDJH2 was linked with vectors pT7-7 and pRSETs. Then they were transformed into E. coli JM109 (DE3) respectively. Expression of subclones was achieved in E. coli JM109 (DE3) with IPTG inducement. SDS-PAGE showed that the molecular weights of products were 68kd and 23 kd respectively. The amount of production seemed to be higher than that of the outer membrane proteins of L. interrogans serovar strain 017 in nature. Immunoblotting of pDJt and pDJrB2 (both are subclones) with the specific antiserum of anti-OMP of L. interrogans serovar lai strain 017 and the experiment of initiative immuno-protection in guinea pigs showed both protein-68 kd and 23 kd might be the antigens of immuno-protection on the outer membrane of L. interrogans serovar lai strain 017.

Animals↗
PubMed1996

[Color analysis of Vita shade guide].

In order to understand the reliability of the Vita Shade Guide and make it more resonably in applying, a series of tests were accomplished. Three Vita shade guides were selected in Beijing hospitals. By using the international color standard CIE1976LAB color system and CS-5 Spectrocolorimeter to measure, test and analyse the characteristics of the shade guides including the degree of color, color distribution, color stability and color difference. The results indicate: The tabs of each shade guide demonstrated the greatest color stability; most of the average color difference among the same number tabs of each guide are less than 1.5 NBS and the color range of shade guides are more limited than that of Chinese teeth crown.

China↗
PubMed1996

[Dynamic analysis of cell surface markers in acute leukemias unclassified with immunologic criteria].

In order to study the cell origin of acute leukemia with lack of lineage specific antigen expression, the dynamic change of cell surface markers in 25 patients of acute leukemia unclassified with immunologic criteria were analysed by using APAAP immunoenzymatic method with monoclonal antibodies after chemotherapy or relapse. The results showed that 5 patients, whose leukemic cells expressed only CD38 antigen in the first visit, expressed T cell differentiated antigen after chemotherapy or relapse. 4 patients, who expressed B cell specific markers after chemotherapy or relapse, all expressed only CD9 antigen in the first visit. 4 of the 6 patients who expressed only HLA-DR antigen were found to have B cell markers on their leukemic cells surface after chemotherapy or relapse. One patient expressed B cell surface markers after chemotherapy and another expressed T cell surface markers after relapse, both of them expressed CD38 and HLA-DR antigens in the first visit. In 4 other patients whose leukemic cells were lacking of in any cell differentiated antigen expressing, one expressed B cell markers and another expressed T cell markers after chemotherapy. The change of cell surface markers showed the evolution and progression of leukemic cell clone. Dynamic study is useful to distinguish the cell origin of leukemia.

Acute Disease↗
PubMed1995

Direct measurement of intratumor dose-rate distributions in experimental xenografts treated with 90Y-labeled radioimmunotherapy.

PURPOSE: To measure, quantify, and evaluate the planar dose-rate distribution for human tumor xenografts implanted into mice that are treated with 90Y-labeled monoclonal antibodies or bispecific antibodies and 90Y-labeled haptens. METHODS AND MATERIALS: Twenty-five LS174T human colon carcinoma tumors grown subcutaneously in nude mice were treated with 90Y by either directly labeled ZCE025 or bispecific ECA001-DBX antibody systems. A simple, quick technique using GAF radiochromic medium determined the dose-rate distribution in a plane passing through the tumor center. The dose-rate distribution is generated from exposure to activity situated in one-half of the tumor (0.045 to 0.83 g). RESULTS: Planar dose-rate distributions were obtained from the tumor xenografts. Planar dose-rate histograms were computed along with the coefficients of variance and skewness of the distributions. The observed dose-rate distributions were quantitatively compared to those calculated for a uniformly distributed activity in a half-ellipsoid of the same volume and approximate shape as the tumor half. The observed dose-rate distributions were usually broader with a more positive coefficient of skewness than the dose-rate distributions calculated from the uniformly active half-ellipsoids. For 90Y, tumor shape plays an important role in determining the minimum tumor dose. For these tumors, the tumor minimum dose-rate is always observed along the edge, usually where the edge curvature is most convex. Larger tumors tended to have broader dose-rate distributions and more positive coefficients of skewness. Exceptions to this trend were associated with dose-rate maxima displaced from the central regions due to activity heterogeneity or tumor size greatly exceeding the range of emission. Calculations for dose rate from the conventional Medical Internal Radiation Dose (MIRD) formulation exceeded the average and minimum dose rate derived from radiochromic media. The coefficient of skewness became more positive for increasing time between injection and tumor excision, consistent with the activity evolving into a more uniform activity distribution. CONCLUSION: Using radiochromic media to measure the spatial dose-rate distribution is a valuable method for comparing the dose-rate heterogeneity among experimental tumor xenografts in animals treated with radiolabeled antibodies. Tumor size (relative to the particle range) and changes in activity distribution radiolabeled antibodies. Tumor size (relative to the particle range) and changes in activity distribution affect the dose-rate distribution that are reflected by changes in the coefficients of skewness and variation of the dose-rate area histogram. The increase in coefficients of variation and skewness with tumor size and time results from the size of the 90Y beta particle penetration range that either exceeds or is comparable to the tumor dimensions. The minimum dose rate is more dependent, relative to the average and the maximum dose rates, on the curvature of the tumor surface.

Animals↗
PubMed1995

Effects of long-term acclimatization in lowlanders migrating to high altitude: comparison with high altitude residents.

The physiological response to submaximal and maximal exercise was assessed in lowlanders and Tibetans at low (500 m above sea level) and high altitude (HA, 3,680 m). The times spent at HA by the lowland migrators was 8 days (n = 60), 7 months (n = 60, same group), 15 months (n = 29) and 27 months (n = 29). After the 15-month stay at HA, the maximal oxygen uptake (VO2max) and maximal heart rate of the lowland migrators almost reached those of the HA native residents (Tibetans, n = 57), but their total work capacity and the gross efficiency (eta) of mechanical work remained lower than those of the Tibetans. The rate of VO2max achieved at 90 W by the Tibetans was lower than that of the lowland migrators. It was concluded that, at HA, the lowlanders regained much of the aerobic capacity which they had lost initially. However, they did not attain the same gross mechanical efficiency as the Tibetans, who seemed to be at an advantage in respect of work at HA.

Acclimatization↗
PubMed1995

A multicentred phase III comparative clinical trial of Mesigyna, Cyclofem and Injectable No. 1 given monthly by intramuscular injection to Chinese women. I. Contraceptive efficacy and sid effects.

A phase III clinical study was carried out among 5680 fertile Chinese women to evaluate efficacy and side effects of three monthly injectable contraceptives: Mesigyna, Cyclofem and Chinese Injectable No. 1. When used in a once-a-month treatment schedule (part 1 of study), the effectiveness of Chinese Injectable No. 1 was unacceptably low; 36 pregnancies occurred during the first 1743 women-months of use, 16 before the second injection. The study was restarted with a revised injection schedule for Injectable No. 1: two injections separated by 9 +/- 1 days during the first month and subsequent injections given 10-12 days after the onset of bleeding, or if no bleeding occurred, 28 days after previous injection. In part 2 of the study, 988, 990 and 992 subjects were provided Mesigyna, Cyclofem and Injectable No. 1, respectively. Life-table pregnancy rates at one year were 0.41%, 0% and 0.77% (p < 0.05), respectively; the overall discontinuation rates at one year were 13.9%, 19.1% and 20.4% (p < 0.001). Discontinuation rates for bleeding problems were significantly different between the groups: discontinuation rates for amenorrhea were 0.58%, 3.71% and 0.68% (p < 0.001) for Mesigyna, Cyclofem and Injectable No. 1; for other bleeding problems, the rates were 4.88%, 8.38% and 12.64% (p < 0.001). There were no significant differences between the groups regarding discontinuation for other medical or non-medical reasons. Mean weight changes after one year of use were small: 0.73, 0.86 and 0.17 kg for the three groups, respectively. Both Mesigyna and Cyclofem were very effective for contraception, but Mesigyna appeared to be tolerated slightly better with regard to cycle control; the modified dose regimen for Injectable No. 1 also gave a low pregnancy rate but was associated with higher rates of discontinuation.

Adolescent↗