Biomedical subjects

S Song

Publications and source records attributed to S Song.

At least 127 records · Page 7Linked to original sources

PubMed1999

Once-a-month treatment with a combination of mifepristone and the prostaglandin analogue misoprostol.

In this two centre study, the efficacy of 200 mg mifepristone orally followed 48 h later by 0.4 mg misoprostol orally for menstrual regulation was investigated. The dose of mifepristone was taken the day before the expected day of menstruation. Each volunteer was planned to participate for up to 6 months. A plasma beta human chorionic gonadotrophin (HCG) was measured on the day of mifepristone intake. The study was disrupted prematurely due to low efficacy. In 125 treatment cycles the overall pregnancy rate was 17.6% (22 pregnancies) and the rate of continuing pregnancies (failure) was 4.0%. Eight women discontinued the study due to bleeding irregularities which were seen in 15 cycles (12%). These effects on bleeding pattern made the timing of treatment day difficult. Late luteal phase treatment with a combination of mifepristone and misoprostol is not adequately effective for menstrual regulation.

Abortifacient Agents, Nonsteroidal↗

PubMed1999

Pregnant women and car restraints: beliefs and practices.

OBJECTIVE: Motor vehicle collisions are a leading cause of death and disability in pregnant women. The purpose of this study was to examine current restraint practices by pregnant women. Additionally, the beliefs and knowledge of pregnant women about restraint laws and effectiveness were studied. METHODS: From May of 1997 to January of 1998, women were surveyed at initial prenatal visit at four obstetrical clinics. Data collected included age, gravida, ethnicity, educational level attained, payor source, restraint use, and knowledge of effectiveness of restraint use. RESULTS: A total of 807 women completed surveys. Most always wore restraints before pregnancy, but increased restraint use during pregnancy (79% vs. 86%, chi2, p = 0.02). Only 52% used restraints properly. Significantly fewer women believed restraints were beneficial to mother and fetus in late pregnancy compared with early pregnancy. Only 21% of women were educated on proper restraint use during pregnancy. Comparison by payor mix showed no difference in use or education received. CONCLUSIONS: Most women use restraints and continue to do so during pregnancy, but they use them improperly. Pregnant women are familiar with mandatory restraint laws but are less informed about restraint use in pregnancy. Few women receive education from health care providers about proper restraint use. This study highlights the need for aggressive educational efforts to improve car restraint use in pregnant women, thereby reduce maternal and fetal injury and death.

Accidents, Traffic↗

PubMed1999

The human papillomavirus type 16 E6 gene alone is sufficient to induce carcinomas in transgenic animals.

High-risk human papillomaviruses (HPVs) are the causative agents of certain human cancers. HPV type 16 (HPV16) is the papillomavirus most frequently associated with cervical cancer in women. The E6 and E7 genes of HPV are expressed in cells derived from these cancers and can transform cells in tissue culture. Animal experiments have demonstrated that E6 and E7 together cause tumors. We showed previously that E6 and E7 together or E7 alone could induce skin tumors in mice when these genes were expressed in the basal epithelia of the skin. In this study, we investigated the role that the E6 gene plays in carcinogenesis. We generated K14E6 transgenic mice, in which the HPV16 E6 gene was directed in its expression by the human keratin 14 promoter (hK14) to the basal layer of the epidermis. We found that E6 induced cellular hyperproliferation and epidermal hyperplasia and caused skin tumors in adult mice. Interestingly, the tumors derived from E6 were mostly malignant, as opposed to the tumors from E7 mice, which were mostly benign. This result leads us to hypothesize that E6 may contribute differently than E7 to HPV-associated carcinogenesis; whereas E7 primarily contributes to the early stages of carcinogenesis that lead to the formation of benign tumors, E6 primarily contributes to the late stages of carcinogenesis that lead to malignancy.

Animals↗

PubMed1999

Complex mediation of uterine endometrial epithelial cell growth by insulin-like growth factor-II (IGF-II) and IGF-binding protein-2.

The coexpression of IGF (-I and -II) peptides, corresponding receptors, and IGF binding proteins (IGFBPs) in uterine endometrium suggests that a significant component of IGF action in this tissue is via autocrine or paracrine pathways, or both. The present study examined whether IGF-II and a major uterine-expressed IGF-II binding protein, IGFBP-2, modulate endometrial epithelial cell mitogenesis. Serum-deprived porcine endometrial glandular epithelial (GE) cells of early pregnancy were treated with various concentrations of IGFs, recombinant porcine (rp) IGFBP-2, or both, and examined for changes in cellular mitogenesis by incorporation of [(3)H]thymidine into DNA. Recombinant human (rh) IGF-II stimulated DNA synthesis in a dose-dependent manner. Human [Leu(27)]-IGF-II, an analog with selective affinity for the IGF-II (type II) receptor, increased thymidine uptake by twofold compared with untreated GE cells. When added in combination with an equimolar concentration of rhIGF-I, [Leu(27)]-IGF-II or rhIGF-II stimulated thymidine incorporation to a greater extent than did rhIGF-I alone. Ligand blot analysis of GE cell conditioned medium revealed the presence of four IGFBPs with molecular masses of 48, 31, 23, and 15 kDa. Physiological concentrations of rpIGFBP-2 (nM range) increased both basal and IGF-induced DNA synthesis in GE cells. At equimolar concentrations, Des(1-6)IGF-II (an IGF-II analog with much reduced affinity for IGFBPs) and rpIGFBP-2 had additive effects on GE cell mitogenesis, suggesting that the IGFBP-2 modulation of uterine cell growth may involve both IGF-dependent and IGF-independent pathways. Our results demonstrate the complex interplay of IGF system components in uterine endometrial epithelial growth regulation in vitro, identify IGF-II and IGFBP-2 as locally coexpressed uterine epithelial cell mitogens, and suggest the presence of a functional signaling pathway by which IGF-II stimulates epithelial cell proliferation via the type II receptor.

Animals↗

PubMed1999

Effect of PSC 833, a P-glycoprotein modulator, on the disposition of vincristine and digoxin in rats.

PSC 833 has been used to overcome the phenomenon of multidrug resistance by inhibiting the P-glycoprotein (P-gp)-mediated efflux of antitumor drugs from tumor cells. Because P-gp expressed in several normal tissues may affect the disposition of its substrates, we examined the dose-dependent effect of PSC 833 on the disposition of vincristine (VCR) and digoxin (DGX) in rats. One-tenth milligram per kilogram PSC 833 was sufficient to significantly reduce the biliary excretion clearance of DGX from 3.0 ml/min/kg to 0.5 ml/min/kg, whereas 3 mg/kg PSC 833 was needed to significantly reduce the biliary excretion clearance of VCR from 36 ml/min/kg to 9 ml/min/kg. Three milligrams per kilogram PSC 833 significantly reduced the renal clearance of VCR by 30% but did not affect that of DGX significantly. The tissue-to-plasma DGX concentration ratio in the brain at 6 h after administration (0.34 versus 1.64), but not that of VCR at 2 h (1.07 versus 1.37), was significantly increased by PSC 833, 3 mg/kg. The differential effect of PSC 833 on the disposition of VCR and DGX may be ascribed to the different degree of contribution of P-gp to the disposition of these ligands.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1999

A double blind observation for therapeutic effects of the tong luo kai bi tablets on rheumatoid arthritis.

The therapeutic effects of the Tong Luo Kai Bi Tablets [symbol: see text] in 120 patients with rheumatoid arthritis were observed in this clinical trial by the randomized double blind method. Both the observed group and the control group each had 60 patients. In the observed group treated with the Tong Luo Kai Bi Tablets, 1 case (1.7%) was cured clinically, 27 cases (45.0%) improved markedly, 26 cases (43.3%) improved, with a total effective rate of 90.0%. In the control group treated with Rheumatic Semen Strychni Tablets [symbol: see text], no case was cured, 16 cases (26.7%) improved markedly, 33 cases (55.0%) improved, with a total effective rate of 81.7%. Statistical data showed the Tong Luo Kai Bi Tablets had much better therapeutic effectiveness clinically than the Rheumatic Semen Strychni Tablets (P < 0.05).

Adult↗

PubMed1999

[Microvessel quantitation and expression of VEGF in colorectal tumors].

OBJECTIVE: To evaluate angiogenesis in colorectal tumorigenesis and to assess the prognostic significance of microvessel quantitation and VEGF status. METHODS: Thirty two colorectal carcinomas, 5 adenomas and 10 normal mucosa were studied immunohistochemically for microvessels and expression of VEGF. RESULTS: The mean vascular density (MVD) was 11 +/- 4 in normal mucosa, 28 +/- 11 in adenomas, and 50 +/- 22 in carcinomas (normal versus adenomas P > 0.05; normal versus carcinomas P < 0.01; adenomas versus carcinomas P < 0.05). MVD varied with tumor cell differentiation and tumor stage, but the differences were not significant. The expression of VEGF is closely associated with angiogenesis. Both MVD and VEGF expression were associated with prognosis. CONCLUSION: VEGF status and MVD are of prognostic significance in colorectal cancer patients.

Colorectal Neoplasms↗

PubMed1999

[Cloning and monoclonal antibody preparation of VEGF receptor KDR extracellular V-VII domain and KDR expression in carcinomas of different origins].

OBJECTIVE: To examine the expression of VEGF receptor KDR in carcinomas of different origins and provide possibility of exploring its relation to tumor growth and metastasis. METHODS: VEGF receptor KDR cDNA (V-VII) fragment was cloned from human umbilical vein with RT-PCR and expressed in E. coli Jm109. The purified GST-KDR fusion protein was used to immunize Balb/c mice and monoclonal antibody against KDR was prepared. With this monoclonal antibody, tumor tissue and related normal tissue of different origins were examined immunohistochemically for KDR expression. RESULTS: The frequency and intensity of KDR expression in different tumor tissues were obviously different. Transitional-cell cancer of urinary bladder was 100% KDR positive and with highest intensity, while KDR expression in breast and intestinal adenocarcinoma was weaker and that in squamous-cell carcinoma of the lung was weakest. Moreover, KDR was also weakly expressed in other cells, such as smooth muscle cells and interstitial cells. CONCLUSION: VEGF receptor is expressed not only in the endothelial cells of tumor vasculature, but also in tumor cells. Tumor cell expression of KDR varies in intensity with tumors of different origins. The possible significance of VEGF receptor expression with regard to tumor cell proliferation and metastasis is discussed.

Animals↗

PubMed1999

[Diagnosis and treatment of familial adenomatous polyposis].

OBJECTIVE: To summarize the experience with diagnosis and therapy of familial adenomatous polyposis (FAP). METHODS: Thirteen patients with FAP who had undergone total colectomy were analyzed retrospectively. RESULTS: In 5 patients with benign and 8 patients with malignant adenomatous polyposis, their average age at operation was 31.5 years (range 10 - 57), 25 years in benign patients and 36 years in malignant patients. Familial inherited histories were found in 8 patients in 6 families. Nineteen patients were determined in 6 families in 3 generations. Seven familial members died of colorectal cancer in 4 families. History lasted 2 - 20 years. The number of adenomatous polyposis was more than 100. All patients underwent total colectomy, ileostomy or anus-preserving surgery with or without ileal pouch. All patients without canceration survived. The longest one exceeded 25 years, but 3/8 patients with canceration developed metastasis of liver, brain and abdomen within 6 months after surgery. CONCLUSIONS: FAP will turn to be cancer if not removed. Total colectomy or proctocolectomy should be performed before canceration. Total colectomy, preserving muscular sheath of the rectum after mucosectomy, ileal pouch-anal anastomosis may be the operative choice for FAP.

Adenomatous Polyposis Coli↗

PubMed1999

[Experimental study of radiofrequency thermocoagulation and applied anatomy of posterior rami of lumbar nerves].

OBJECTIVE: To determine points of radiofrequency thermocoagulation of the posterior rami of the lumbar nerves and to choose an effective temperature at which the conduction of painful impulse can be blocked. METHODS: The posterior rami of the lumbar nerves were dissected in 15 corpses of adults. The ultrastructure of nerve fibres, changes of sensary conduction velocity (SCV) and the waveform of the unmedullated fibres which conduct painful impulse (c wave) were observed after the sciatic nerves of rabbits were coagulated at various temperatures (60 degrees C, 70 degrees C, 80 degrees C, 90 degrees C). RESULTS: "Transverse Process Root Area" and "Transverse Process Point" can be regarded as primary marks of thermocoagulation of the posterior rami of the lumbar nerves. Stimulation of square-wave can make the location more accurate. While the temperature of thermocoagulation reached 80 degrees C, none of painful afferent nerve fibres survived. CONCLUSIONS: With accurate location and good control of temperature, radiofrequency thermocoagulation will be an effective therapy for the patients suffering from pain resulted from pathological changes of the posterior rami of the lumbar nerves.

Adult↗

PubMed1999

[Influence of modulatory activity of wound fluid on the characteristics of fibroblasts from irradiation and the action of phenytoin sodium].

OBJECTIVE: Influence of irradiation and phenytoin sodium on modulatory activities of wound fluid on proliferation of fibroblasts and collagen synthesis was studied. METHODS: The male Wistar rats were used in this study. The rats were divided into irradiated and non-irradiated groups, and in each of them it was subdivided into phenytoin group and control. A 7 cm long incisional wound was made on the back of each rat, in which a polyvinyl alcohol sponge (PVAS) with a size of 1.0 cm x 0.4 cm was implanted into the wound and the wound was sutured up. The PVAS was prepared by rinsing in running water over night and then was boiled for 30 minutes. Before implantation, the sponge was immersed in phenytoin sodium solution (10 mg/l ml) or normal saline (as control). From each wound the wound fluid and fibroblasts were collected. The methods of incorporation of 3H were adopted to assess the proliferation of fibroblasts and synthesis of collagen. RESULTS: It was shown that proliferation of fibroblasts and collagen synthesis were stimulated by wound fluid remarkably on 5 to 8 days after wounding, and that 6 Gy to total-body irradiation wound decrease this effect. It was also noted that topical phenytoin sodium increased the modulatory activity of wound fluid irrespective of being irradiated or not. CONCLUSION: It could be drawn that, after total-body irradiation, stimulation of hyperplasia of fibroblasts and collagen synthesis by wound fluid was markedly lowered indicating the total-body irradiation resulted in changes of local conditions of the wound which was unbenefitted to repair of tissue cells, while phenytoin sodium could enhance the stimulating action of wound fluid on proliferation of fibroblasts and synthesis of collagen which was beneficial to wound healing.

Animals↗

PubMed1999

[Analysis of trace elements and composition of protein in sika blood].

The levels of trace element and protein were determined in eight male sikas. The results revealed that the levels of phosphorus, zinc, copper, ferrin and manganese were 2.68 mmol/L, 51.3 mumol/L, 21.4 mumol/L, 255.6 mumol/L and 0.16 mumol/L respectively and which were significantly higher than the human normal values. Serum levels of albumin and globulin were 34.9 g/L and 35.5 g/L respectively. Among them, the level of gamma-globulin was the highest (25.2%) which was threefold than the human serum normal value. From the above results, sika blood has great value in medicinal use.

Albumins↗

PubMed1999

[Analysis of hemogram and parameters of biochemistry from sika blood].

The hemogram and parameters of biochemistry were determined in eight male sika. The results showed that the red blood cell count was 125 x 10(8)/L, the mean corpuscular of hemoglobin was 38.7 pg and the mean corpuscular hemoglobin concentration was 970 g/L. It is suggested that there are rich hemoiderin and oxygen in sika blood. Moreover, the seven kinds of enzyme observed in the study were significantly higher than the human normal values. Serum levels of creatine phosphate kinase (CPK), hydroxybutyrate dehydrogenase (a-HBD) and CK-MB were 327 U/L, 639 U/L and 772 U/L respectively and which were seven to ten times higher than human normal values. It is indicated the activity of enzyme should be protected when the sika blood was used as raw material of medicine.

Animals↗

PubMed1998

Interleukin-10 enhances tumor necrosis factor-alpha activation of HIV-1 transcription in latently infected T cells.

Interleukin-10 (IL-10) is elevated in HIV-1-infected individuals and has been implicated in disease progression. We previously reported that IL-10 cooperates with tumor necrosis factor-alpha (TNF-alpha) to activate HIV-1 expression synergistically in acutely infected monocyte-derived macrophages and the chronically infected U1 promonocytic cell line. To determine whether IL-10 also cooperates with TNF-alpha to activate latent HIV-I expression in lymphocytes, we examined the effects of IL-10 on proviral expression in the chronically infected T-cell line, ACH-2. Although IL-10 inhibited HIV-1 expression acting alone, in combination with suboptimal concentrations of TNF-alpha, IL-10 increased HIV-1 steady-state mRNA expression and p24 core antigen production in ACH-2 cells. Interestingly, IL-10 concentrations that synergistically induced virus also maximally stimulated endogenous TNF-alpha expression, suggesting that cell-derived TNF-alpha may contribute to cytokine synergy. Transfection studies in ACH-2 cells indicated that IL-10 combined with TNF-alpha to activate the HIV-1 long terminal repeat (LTR). IL-10 also cooperated with TNF-alpha to activate HIV-1 LTR in 1G5 cells, a Jurkat T-cell line stably transfected with an LTR-dependent luciferase reporter gene. Pyrrolidine dithiocarbamate, a potent transcriptional inhibitor of the viral LTR, abrogated the cytokine responses in both U1 and ACH-2 cells, suggesting a common TNF-alpha-mediated transcriptional mechanism in these cell types despite their different modes of provirus latency. Taken collectively, these data suggest that IL-10 enhances suboptimal TNF-alpha activation of HIV-1 transcription in chronically infected T-cells at least in part through induction of endogenous TNF-alpha expression.

Cell Line↗

PubMed1998

Sustained secretion of human alpha-1-antitrypsin from murine muscle transduced with adeno-associated virus vectors.

Recombinant adeno-associated virus (AAV) vectors have been used to transduce murine skeletal muscle as a platform for secretion of therapeutic proteins. The utility of this approach for treating alpha-1-antitrypsin (AAT) deficiency was tested in murine myocytes in vitro and in vivo. AAV vectors expressing the human AAT gene from either the cytomegalovirus (CMV) promoter (AAV-C-AT) or the human elongation factor 1-alpha promoter (AAV-E-AT) were examined. In vitro in C2C12 murine myoblasts, the expression levels in transient transfections were similar between the two vectors. One month after transduction, however, the human elongation factor 1 promoter mediated 10-fold higher stable human AAT expression than the CMV promoter. In vivo transduction was performed by injecting doses of up to 1.4 x 10(13) particles into skeletal muscles of several mouse strains (C57BL/6, BALB/c, and SCID). In vivo, the CMV vector mediated higher levels of expression, with sustained serum levels over 800 micrograms/ml in SCID and over 400 micrograms/ml in C57BL/6 mice. These serum concentrations are 100,000-fold higher than those previously observed with AAV vectors in muscle and are at levels which would be therapeutic if achieved in humans. High level expression was delayed for several weeks but was sustained for over 15 wk. Immune responses were dependent upon the mouse strain and the vector dosage. These data suggest that recombinant AAV vector transduction of skeletal muscle could provide a means for replacing AAT or other essential serum proteins but that immune responses may be elicited under certain conditions.

Animals↗

PubMed1998

Sample purification for the analysis of caffeine in tobacco by gas chromatography-mass spectrometry.

A commonly used additive to tobacco products is cocoa. A sensitive an selective method was developed to measure caffeine, a marker for cocoa, in tobacco by using gas chromatography-mass spectrometry (GC-MS). Tobacco components usually produce high background signals in GC-MS analysis. Therefore, a series of extraction steps were designed to effectively purify the tobacco extracts. The analytical recovery of caffeine was 100 when [trimethyl-13C3] caffeine was used as an isotope-dilution reference. A linear calibration curve was generated with caffeine concentration ranging from 0.01 to 20 micrograms/ml. The detection limit of caffeine was 0.02 microgram/ml in the final solution. This method was applied to several commercial tobacco products, of which the corresponding caffeine levels varied from below the detection limit to 125 micrograms/g.

Caffeine↗

PubMed1998

Structure of a basic phospholipase A2 from Agkistrodon halys Pallas at 2.13 A resolution.

The basic phospholipase A2 isolated from the venom of Agkistrodon halys Pallas (Agkistrodon blomhoffii Brevicaudus) is a hemolytic toxin and one of the few PLA2's capable of hydrolyzing the phospholipids of E. coli membranes in the presence of a bactericidal/permeability-increasing protein (BPI) of neutrophils. The crystal structure has been determined and refined at 2.13 A to an R factor of 16.5% (F > 3sigma) with excellent stereochemistry. A superposition of the two molecules in the asymmetric unit gives an r. m.s. deviation of 0.326 A for all Calpha atoms. The refined structure allowed a detailed comparison with other PLA2 species of known structures. The overall architecture is similar to those of other PLA2's with a few significant differences. One of which is in the region connecting the N-terminal helix and the Ca2+-binding loop. Unexpectedly, the conformation of the peptide plane Cys29-Gly30 in the Ca2+-binding loop is very different to that of other PLA2's. The amide NH of Gly30 does not point toward the proposed site for stabilization of the tetrahedral intermediate oxyanion of the substrate analogue. The structure includes four residues which occur less frequently in other PLA2's. His1, Arg6 and Trp70 located at the interfacial recognition site may play an important role in the interaction with aggregated substrates, while Trp77 contributes to the hydrophobic interactions between the beta-wing and the main body of the molecule. This structure analysis reveals that two clusters of basic residues are located at or near the interfacial recognition site, forming an asymmetric positively charge distribution. In contrast to the acidic isoform, the present enzyme is a dimer in the crystalline state. The special phospholipid hydrolysis behaviors are discussed in the light of the structure determined.

Agkistrodon↗

PubMed1998

Structure of holo-glyceraldehyde-3-phosphate dehydrogenase from Palinurus versicolor refined at 2 A resolution.

The crystal structure of holo-glyceraldehyde-3-phosphate dehydrogenase from Palinurus versicolor, South China sea lobster, was determined and refined at 2 A resolution to an R factor of 17.1% and reasonable stereochemistry. The structure refinement has not altered the overall structure of GAPDH from this lobster species. However, some local changes in conformation and the inclusion of ordered solvent model have resulted in a substantial improvement in the accuracy of the structure. Structure analysis reveals that the two subunits including NAD+ in the asymmetric unit are remarkably similar. The thermal differences between the two subunits found in some regions of the NAD+-binding domain may originate from different crystallographic environments rather than from an inherent molecular asymmetry. In this structure, the side chain of Arg194 does not point toward the active site but forms an ion pair with Asp293 from a neighboring subunit. Structural comparisons with other GAPDH's of known structure reveal that obvious contrast exists between mesophilic and thermophilic GAPDH mainly in the catalytic domain with significant conformational differences in the S-loop, beta7-strand and loop 120-125; the P-axis interface is more conserved than the R- and Q-axis interfaces and the catalytic domain is more conserved than the NAD+-binding domain. Some possible factors affecting the thermostability of this enzyme are tentatively analyzed by comparison with the highly refined structures of thermophilic enzymes.

Allosteric Site↗