Biomedical subjects

L Song

Publications and source records attributed to L Song.

At least 109 records · Page 6Linked to original sources

PubMed1999

Oxidative stress oppositely modulates protein tyrosine phosphorylation stimulated by muscarinic G protein-coupled and epidermal growth factor receptors.

This study's goals were to more fully define the activation of protein tyrosine phosphorylation stimulated by muscarinic receptors, to test if this signaling process is affected by oxidative stress induced by H2O2, and to compare the effects of H2O2 on protein tyrosine phosphorylation activated by epidermal growth factor (EGF) receptors. Experiments used human neuroblastoma SH-SY5Y cells which express endogenous M3 muscarinic and EGF receptors. Carbachol induced time-dependent increases in phosphotyrosine immunoreactivity of several protein bands, which were quantitated, and immunoprecipitation was used to identify the adhesion-related proteins focal adhesion kinase, p130Cas/HEF1, and paxillin, and three shc adapter proteins. Carbachol-induced tyrosine phosphorylation of the adhesion-related proteins was mediated by muscarinic receptors, and was inhibited by a src family kinase inhibitor, PP1. That carbachol can activate src family kinases was indicated further by the finding that carbachol induced an increase in tyrosine phosphorylation of p120-src substrate, which was inhibited by PP1. Oxidative stress induced by H2O2 concentration dependently inhibited carbachol-induced tyrosine phosphorylation of each of the adhesion-related proteins. EGF increased the phosphotyrosine immunoreactivity of 180- and 116-kDa proteins, identified as the EGF receptor and Cbl, respectively. In contrast to the results with carbachol, H2O2 potentiated EGF-induced tyrosine phosphorylation. These results demonstrate that muscarinic receptor activation induces previously unrecognized increases in tyrosine phosphorylation, and that this signaling process is impaired by H2O2, whereas protein tyrosine phosphorylation stimulated by EGF is increased by H2O2. Thus, oxidative stress can oppositely modulate protein tyrosine phosphorylation induced by activation of G protein-coupled and growth factor receptors in the same cells.

Carbachol↗

PubMed1999

Separation of double-stranded DNA fragments in plastic capillary electrophoresis chips by using E99P69E99 as separation medium.

The separation of double-stranded DNA (dsDNA) fragments in polymethylmethacrylate (PMMA) capillary electrophoresis (CE) chips by using E99P69E99 as a separation medium has been demonstrated. The PMMA CE chips were simply manufactured by micromachining and adhesive tape sealing. To make the separation channel compatible with the separation medium, a dynamic nonionic surfactant coating procedure was developed, which made the plastic separation channel sufficiently hydrophilic to allow the separation medium to fill the channel by capillary action. Subsequent separation of DNA fragments was successful with a separation efficiency of the order of 10(4) theoretical plates over an effective separation distance of 1.5 cm. By using an applied electric field strength of 200 V/cm, the separation of low DNA mass ladder was completed within 5 min. The simple coating procedure, together with the self-assembled viscosity-adjustable separation medium, should be useful to meet some of the essential requirements for developing single-use disposable CE chips. Coating the channels with polymer blends of PMMA and the separation medium also showed promise.

Animals↗

PubMed1999

Poly(N-isopropylacrylamide)-g-poly(ethyleneoxide) for high resolution and high speed separation of DNA by capillary electrophoresis.

A new separation medium, poly(N-isopropylacrylamide)-g-poly(ethyleneoxide) (PNI-PAM-g-PEO) solution, used for double-stranded (ds) DNA separation by capillary electrophoresis (CE) is presented. This type of grafted copolymer has a good self-coating ability for quartz capillary tubing and a slightly temperature-dependent viscosity-adjustable property, making it easier to use. One bp resolution was achieved within 12.5 min by using 8% w/v PNIPAM-gPEO in 1 x TBE (Tris-borate-ethylenediaminetetraaceticacid) buffer with an effective column length of 10 cm and an applied electric field strength of 200 V/cm. The PNIPAM-g-PEO solutions had a high sieving ability for relatively small sized DNAs with the relative standard derivation for the first 10 runs being less than 0.9% by using the same polymer solution. With 8% w/v PNIPAM-g-PEO solution in a 1.5 cm column and 2400 V as the running voltage, phiX174/HaeIII digest could be clearly separated within 24 s.

Acrylamides↗

PubMed1999

Bisindolylmaleimide VIII facilitates Fas-mediated apoptosis and inhibits T cell-mediated autoimmune diseases.

Fas-mediated apoptosis is essential for the elimination of cells, and impaired apoptosis can have severe detrimental consequences. Bisindolylmaleimide VIII potentiated Fas-mediated apoptosis in human astrocytoma 1321N1 cells and in Molt-4T cells, both of which were devoid of apoptosis induced by anti-Fas antibody in the absence of bisindolylmaleimide VIII, and in Jurkat and CEM-6 T cells, which showed slight and moderate apoptotic responses, respectively, to low levels of Fas stimulation. Potentiation of Fas-mediated apoptosis by bisindolylmaleimide VIII was selective for activated, rather than non-activated, T cells, and was Fas-dependent, as it was not observed in T cells from Fas-deficient lpr/lpr mice. Administration of bisindolylmaleimide VIII to rats during autoantigen stimulation prevented the development of symptoms of T cell-mediated autoimmune diseases in two models, the Lewis rat model of experimental allergic encephalitis and the Lewis adjuvant arthritis model. Thus, the use of agents such as bisindolylmaleimide VIII may be therapeutically useful for supporting more effective elimination of detrimental cells through enhancement of Fas-dependent apoptosis signaling.

Animals↗

PubMed1999

Production of gelatinases and tissue inhibitors of matrix metalloproteinases by equine ovarian stromal cells In vitro.

Matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) play very important roles in extracellular matrix (ECM) remodeling in ovarian follicle growth and ovulation. Equine follicles are embedded in cortex that is at the center of the ovary, and they must expand/emigrate to the fossa, the only site in the ovary for ovulation. Therefore, equine ovarian stromal cells (EOSC) are probably involved in ECM remodeling during follicle growth. This study examined whether cultured EOSC synthesize gelatinases and TIMPs, molecules essential for ECM remodeling in other systems. Results showed that cultured EOSC (passage 3-8) had a fibroblast-like morphology and were positive for alpha-smooth muscle actin and type I procollagen by immunostaining. Gelatinase A (MMP-2), gelatinase B (MMP-9), TIMP-1, and TIMP-2 were present in EOSC-conditioned medium, and TIMP-3 in ECM of EOSC. Transforming growth factor beta significantly stimulated the activity of gelatinases A and B and TIMP-1 in conditioned medium from EOSC (p < 0.05). Phorbol 12-myristate 13-acetate also significantly stimulated the activity of gelatinases A and B and TIMP-1 in conditioned medium and of TIMP-3 in ECM (p < 0.05). Our results suggest that EOSC produce important components of the ECM remodeling machinery and, therefore, may play a role in the ECM remodeling during follicle growth in this species.

Animals↗

PubMed1999

Long-term remodeling of vascularized and nonvascularized onlay bone grafts: a macroscopic and microscopic analysis.

The present study was performed to compare vascularized and nonvascularized onlay bone grafts to investigate the potential effect of graft-to-recipient bed orientation on long-term bone remodeling and changes in thickness and microarchitectural patterns of remodeling within the bone grafts. In two groups of 10 rabbits each, bone grafts were raised bilaterally from the supraorbital processes and placed subperiosteally on the zygomatic arch. The bone grafts were oriented parallel to the zygomatic arch on one side and perpendicular to the arch on the contralateral side. In the first group, vascularized bone grafts were transferred based on the auricularis anterior muscle, and in the second group nonvascularized bone grafts were transferred. Fluorochrome markers were injected during the last 3 months of animal survival, and animals were killed either 6 or 12 months postoperatively. The nonvascularized augmented zygoma showed no significant change in thickness 6 months after bone graft placement and a significant decrease in thickness 1 year after graft placement (p < 0.01). The vascularized augmented zygoma showed a slight but statistically significant decrease in thickness 6 months after graft placement (p < 0.003), with no significant difference relative to its initial thickness 1 year after graft placement. In animals killed 6 months after bone graft placement, both the rate of remodeling and the bone deposition rate measured during the last 3 months of survival were significantly higher in the vascularized bone grafts compared with their nonvascularized counterparts (p < 0.02). By 1 year postoperatively, there were no significant differences in thickness, mineral apposition rate, or osteon density between bone grafts oriented perpendicular and parallel to the zygomatic arch. These findings indicate that the vascularity of a bone graft has a significant effect on long-term thickness and histomorphometric parameters of bone remodeling, whereas the direction of placement of a subperiosteal graft relative to the recipient bed has minimal effect on these parameters. In vascularized bone grafts, both bone remodeling and deposition are accelerated during the initial period following graft placement. Continued bone deposition renders vascularized grafts better suited for the long-term maintenance of thickness and contour relative to nonvascularized grafts.

Animals↗

PubMed1999

Kidney aminopeptidase A and hypertension, part I: spontaneously hypertensive rats.

Tissue and plasma levels of aminopeptidase A (APA), the principal enzyme that hydrolyzes angiotensin II (Ang II) to angiotensin III, were measured in spontaneously hypertensive rats (SHR) and their normotensive control strain at 3 different ages corresponding to prehypertensive (4 weeks), developing (8 weeks), and established (16 weeks) phases of hypertension. Plasma APA activity was significantly but modestly elevated in SHR at all 3 ages compared with normotensive Wistar-Kyoto rats. Likewise, levels of APA in brain, heart, and adrenal gland were generally, but again only moderately, elevated in SHR at all ages. However, a large increase in APA activity was seen within the kidney in which APA levels were elevated 41%, 51%, and 68% in SHR at 4, 8, and 16 weeks of age, respectively. Kidney APA levels were also significantly increased in immunoblots from 8- and 16-week-old SHR. Glomeruli isolated from 16-week-old SHR had 57% higher APA activity and increased immunoreactivity compared with Wistar-Kyoto rats. To determine whether the increase in kidney APA activity in SHR was related to Ang II levels, SHR were treated for 2 weeks with the angiotensin-converting enzyme inhibitor captopril. Captopril treatment reduced blood pressure to normotensive values and resulted in a 25% reduction in kidney APA activity. These results suggest that APA expression in the kidney may be regulated by activity of the renin-angiotensin system. If so, this would further suggest that upregulation of APA during conditions in which Ang II levels were elevated would have a protective effect against Ang II-mediated cardiovascular diseases, whereas a decrease in APA expression or a failure to upregulate would exacerbate such conditions.

Aminopeptidases↗

PubMed1999

Kidney aminopeptidase A and hypertension, part II: effects of angiotensin II.

Aminopeptidase A (APA) is the principal enzyme that metabolizes angiotensin II (Ang II) to angiotensin III. Previously, we showed that kidney APA was elevated in spontaneously hypertensive rats and was reduced after angiotensin-converting enzyme inhibition. In the present study, we sought to determine whether kidney APA expression was altered after chronically elevated Ang II, either exogenously delivered via osmotic minipumps or endogenously produced in two-kidney, one clip (2K1C) hypertensive rats. Ang II (200 ng. kg-1. min-1) was infused subcutaneously for 1 or 2 weeks by osmotic minipumps, and 2K1C rats were tested 4 weeks after unilateral renal artery clipping. Blood pressure was not significantly elevated in the Ang II-infused animals but was significantly increased at 3 and 4 weeks in the 2K1C animals. APA was significantly elevated approximately 2-fold in kidney cortical membranes from Ang II-infused animals but was decreased 45% in the clipped kidney and 18% in the nonclipped kidneys from 2K1C animals. Isolated glomeruli from Ang II-infused animals and the nonclipped kidneys from 2K1C animals had markedly higher APA activity and immunoreactivity. Likewise, histochemical and immunohistochemical studies indicated that APA levels were increased in glomeruli from angiotensin-infused animals and in both nonclipped and clipped kidneys from 2K1C animals. In contrast, tubular APA was decreased in tubular elements from 2K1C animals, most markedly in the clipped kidneys. Thus, despite the increase in glomerular APA expression in kidneys from 2K1C animals, the decrease in tubular APA expression is more extensive and accounts for the measured reduction in total APA in cortical homogenates. Because clipped kidneys are not exposed to high blood pressure, these results suggest that glomerular APA expression is positively regulated and tubular APA negatively regulated by Ang II. These results further suggest that changes in kidney APA expression could influence the progression of angiotensin-dependent hypertension.

Aminopeptidases↗

PubMed1999

Linking community-based blood pressure measurement to clinical care: a randomized controlled trial of outreach and tracking by community health workers.

OBJECTIVES: This study assessed the effectiveness of enhanced tracking and follow-up services provided by community health workers in promoting medical follow-up of persons whose elevated blood pressures were detected during blood pressure measurement at urban community sites. METHODS: In a randomized controlled trial, 421 participants received either enhanced or usual referrals to care. Participants were 18 years or older, were either Black or White, and had blood pressure greater than or equal to 140/90 mm Hg and income equal to or less than 200% of poverty. The primary outcome measure was completion of a medical follow-up visit within 90 days of referral. RESULTS: The enhanced intervention increased follow-up by 39.4% (95% confidence interval [CI] = 14%, 71%; P = .001) relative to usual care. Follow-up visits were completed by 65.1% of participants in the intervention group, compared with 46.7% of those in the usual-care group. The number needed to treat was 5 clients (95% CI = 3, 13) per additional follow-up visit realized. CONCLUSIONS: Enhanced tracking and outreach increased the proportion of persons with elevated blood pressure detected during community measurement who followed up with medical care.

Adolescent↗

PubMed1999

[Common mutation analysis for patients found in Tianjin area with glucose-6-phosphate dehydrogenase deficiency].

OBJECTIVE: To study the types of glucose-6-phosphate dehydrogenase (G6PD) gene mutation in North China and to find the relationship between the mutations and population emigrants. METHODS: DNA samples from 22 unrelated patients(21 male and 1 female) with G6PD deficiency from Tianjin area in North China were studied for the three common mutations by using both mismatched primers mediated polymerase chain reaction/ restriction enzyme analysis and dideoxy fingerprinting methods. RESULTS: Eight patients(8/22, 36.4%) were found to have the mutation R459L(1376G-->T), and seven patients (7/22, 31.8%) were found to have the mutation R463H (1388G-->A). In three of (3/7) other seven patients (7/22), H32R(95A-->G) were detected; one patient (1/3) was identified to have H32R (95A-->G) mutation. CONCLUSION: The three common mutations in South China are also found in North China. However, most of the patients in Tianjin are also the later generations of Southern emigrants.

Asian People↗

PubMed1999

Influences of chloropazine, nimodipine and their combination on the toxic effects of cadmium in liver and kidney of mice.

The influences of the calmodulin antagonist chlorpromazine (CPZ), and calcium channel blocker nimodipine (NIMO) and their combination on cadmium (Cd) poisoning of mice were studied. A series of biochemical parameters including urinary enzyme activities, blood and urine Cd levels, metallothionein (MT) contents in liver and kidney, hepatic ultrastructure and Ca(2+)-Mg2+ ATPase activity in erythrocyte membrane were determined. Animal models for Cd poisoning were established by peritoneal injection of 1/5 LD50 CdCl2. The experimental groups were protected by administration of CPZ, NIMO and CPZ and NIMO in combination 1 h before the injection of CdCl2. Five days later, samples were collected for analysis. The data showed that CPZ could protect kidney tissue against Cd-induced damage, as the urinary gamma-glutamyl-traspeptidase (gamma-GT) and N-acetyl-beta-D-glucosaminidase (NAG) activities were reduced significantly. There was neither evidence of the protective effect of NIMO on kidney tissue nor an indication of a synergistic effect of CPZ and NIMO. Both CPZ and NIMO showed a considerable protective effect against the decrease in Ca(2+)-Mg2+ ATPase activity, and a synergistic action was observed. Cd content in blood was reduced significantly by CPZ or the combination of CPZ and NIMO, but elevated by NIMO. Both CPZ and NIMO considerably increased MT contents in livers and kidneys and ameliorated damaged to the hepatic ultrastructures caused by Cd. The results indicated that these inhibitors could protect mice against the toxic effects of Cd in liver and kidney tissues, while CPZ was more efficient than NIMO. The combination of CPZ and NIMO exerted a synergistic action. The protective action of these two drugs might be relevant to the function of MT.

Animals↗

PubMed1999

[Tubal catheterization for transvaginal gamete intrafallopian transfer: an alternative technique for non-tubal infertility].

OBJECTIVE: To evaluate the outcome of transvaginal gamete intrafallopian transfer (TV-GIFT) for infertile patients with non-tubal factors. METHODS: Controlled ovarian hyperstimulation was used for all patients. Transvaginal ultrasound-guided oocyte retrieval followed by tubal catheterization for transvaginal gamete intrafallopian transfer of 3.3 +/- 2.1 oocytes (range 1-8) and 200,000 sperms in 50 microliters culture medium. RESULTS: The TV-GIFT was used in total of 23 treatment cycles. Of 23 cycles performed for TV-GIFT, the procedure was completed easily in 18 and difficult in 5, resulting in 5 clinical pregnancies(21.7% per cycle), 2 of which resulted in abortion, 2 ongoing pregnancy one was ectopic pregnancy. No pregnancy occurred in four cycles with only one oocyte transferred. CONCLUSIONS: Simple and cost-effective TV-GIFT may achieve a higher pregnancy rate. Compared with laparoscopically directed GIFT, tubal catheterization for TV-GIFT is safe and less invasive. It is an alternative for non-tubal infertility before entering the IVF-ET program.

Adult↗

PubMed1999

[Cardiovascular response to high sustained +Gz stress in dogs].

Objective. To investigate features of electrocardiography (ECG) and arterial pressure in dog during and after +Gz stress. Method. Six anesthetized dogs were catheterized for the measurement of ascending aortic pressure (AP) and common iliac arterial pressure (CIAP). A lead of ECG was monitored continuously. Then, dogs were placed supine in rotatable platform on one arm of an 1.7 m radius centrifuge. The animals were exposed serially to acceleration profiles of up to +7 Gz, consisting of a slow onset to peak acceleration, 90 s peak G, and a rapid decline back to control. A recovery time of at least 20 min was allowed after each acceleration profile. Result. (1) The amplitude of P-wave was influenced by the magnitude of the acceleration (2.3 +/- 0.2 mV at rest vs. 4.5 +/- 0.5 mV at +3 Gz, 4.8 +/- 0.3 mV at +5 Gz and 5.3 +/- 0.7 mV at +7 Gz, respectively P<0.05). (2) It appeared that arterial mean pressure increased and pulse pressure decreased in CIAP during high +Gz stress. (3) AP increased greatly after +Gz stress (17.29 +/- 5.59/11.31 +/- 3.86 kPa at rest vs. 27.53 +/- 6.12/20.62 +/- 1.86 kPa 30s after +7 Gz P<0.01). Conclusion. (1) The change of the amplitude of P-wave reflected the atrial displacement which may be the reason of arrhythmia. (2) The perfusion pressure is an important physiological parameter to the cardiovascular dysfunction during high +Gz stress. (3) Greatly higher AP after +Gz stress could be a feature of vascular exhaustion.

Acceleration↗

PubMed1999

[Apoptosis inducing effect of meisoindigo on K562 cells].

OBJECTIVE: To study the effect of meisoindigo on human chronic myelogenous leukemia (CML) cell line K562 cells for exploring the mechanism of meisoindigo in treatment of CML. METHODS: Multiple methods, including dose-response curve, trypan blue exclusion, cytomorphology, DNA electrophoresis, flow cytometry and TUNEL (TdT mediated dUTP nick and labeling), were used to observe the effect of meisoindigo on K562 cells. RESULTS: Meisoindigo can inhibit the proliferation and induce the apoptosis of K562 cells. CONCLUSION: The therapeutic mechanism of meisoindigo in treating CML may be related with its proliferation inhibiting and apoptosis inducing effect in CML cells.

Apoptosis↗

PubMed1999

[An epidemiological survey and treatment of blindness in Zhangqiu city of Shandong province].

OBJECTIVE: An epidemiological survey of blindness was carried out in Zhangqiu city of Shandong province. METHODS: According to stratified random sampling rule, 11,884 persons were chosen as the sample (the sampling fraction is 1.27%) in the city. The WHO grading system for blindness was followed in the survey. RESULTS: The prevalence of blindness was found to be 0.31%, resulting chiefly from cataract (45.95%), glaucoma (24.32%) and vitreous retinal disease (13.51%). 1 016 cases of blindness caused by cataract were operated for restoration of vision, that were accounted for 73.89% of all cataract blindness estimated from the result of the survey. The rate of intraocular lens implantation in the restorative operations was 84.15% (855/1,016). After operation, the corrected vision in 64.47% of the blindness was >or= 1.0, in 21.26% between 0.6 - 0.9, in 10.24% between 0.3 - 0.5, and in 4.03% between 0.05 - 0.2. CONCLUSION: The epidemiological results show that the main cause of blindness is cataract. So it is the key objective for surgical restoration of vision in the prevention of the blindness in later days.

Adolescent↗

PubMed1999

[Multiresolution analysis based denoising algorithm for dynamic esophageal pH monitoring signal].

A denoising algorithm for dynamic esophageal pH monitoring signal is first introduced in this paper. The algorithm was developed on the basis of multiresolution analysis. The pH monitoring signal was investigated in experiments, then the algorithm was formulated by multiresolution analysis based on discrete dyadic wavelet transform combining with the results of the investigation mentioned above. Application of this algorithm to clinical data processing has proved its satisfactory denoising effect.

Algorithms↗

PubMed1999

[Influence of sample dilution on separation and detection of DNA fragments by capillary electrophoresis].

Capillary electrophoresis has become an important and useful method to separate and determine DNA fragments. In molecular biochemistry, the volume of DNA sample is very small (microL level) and DNA sample is liable to be contaminated and degraded. According to theoretical inference and experiments, we propose that dilution of DNA sample solution can increase separation efficiency and resolution without evidently reducing height of peaks. By this method, the usage efficiency of DNA sample can be improved. It is also demonstrated the separation and detection of DNA fragments by capillary electrophoresis with hydroxyethyl cellulose non-gel sieving matrix and with laser-induced fluorescence charge-coupled device as detector. By using lower concentration non-gel matrix (0.4%), all 8 larger size fragments of lambda DNA/Hind III (125 bp-23 130 bp) can be completely separated. Twenty smaller size fragments of pBR322-Hae III DNA (18 bp-587 bp) can be separated by higher concentration (1.6%) non-gel matrix. As ratio of sample dilution is 10, two adjacent fragment (123 bp and 124 bp) of pBR322-Hae III DNA can be separated.

DNA↗

PubMed1999

Detection of chromosome aberrations in twelve primary gastric cancers by direct chromosome analysis and FISH.

Direct chromosome analysis and FISH were performed on twelve primary gastric carcinomas. Two of them had simple chromosome changes: 48, XX, +8, +20, and 49, XY, +2, +8, +9, and the others had complicated chromosome changes, which includes much more numerical and structural chromosome aberrations. Frequent structural changes in the complicated types involved chromosome 7, 3, 1, 5 and 12 etc. The del 7q was noted in eight cases. The del (3p) and del (1p) were noted in six and five cases, respectively. The results provide some important clues for isolation of the genes related to gastric cancer.

Adenocarcinoma↗