[KLF3 regulates the movement, migration and invasion of breast cancer cells through STAT3]

Objective: To observe the effect of KLF3 on the expression of STAT3 in breast cancer cells, and to explore the potential mechanism of KLF3 affecting the movement, migration and invasion of breast cancer cells. Methods: Firstly, the expression of STAT3 was detected by Western blot, real-time fluorescent quantitative PCR, luciferase reporter system and chromatin immunoprecipitation in breast cancer cells. Secondly, the STAT3 promoter mutant was constructed. The plasmid further confirmed the effect of KLF3 on the activity of STAT3 promoter; the cell scratching test and Transwell method were used to detect the ability of cell movement, migration and invasion. Finally, animal experiments were conducted to verify the effect of knockdown of KLF3 on tumor metastasis in animals. Results: In breast cancer cells, knockdown of KLF3 promoted STAT3 protein expression. The mRNA level of STAT3 was increased by (3.58±0.65) fold after knockdown of KLF3 in MDA-MB-231 cells, while the mRNA level of STAT3 was increased by (2.28±0.19) fold after KLF3 knockdown in MCF-7 cells (P<0.001). KLF3 boundto the promoter region of STAT3. The transcriptional activity of STAT3 increased by (2.47±0.87) fold after knockdown of KLF3 in MDA-MB-231 cells, while the transcriptional activity of STAT3 increased by (2.63±0.65) fold after KLF3 knockdown in MCF-7 cells, P<0.01. KLF3 knockdown inhibitedthe movement,migrate and invade of breast cancer cells. Based on this, silence STAT3 partially reversed the function of KLF3. Knockdown of KLF3 promotedtumor metastasis in mice. Conclusions: KLF3 knockdown can promote the transcriptional activity of STAT3, which promotes the protein expression of the latter. KLF3 can affect the movement, migration and invasion of breast cancer cells through STAT3. KLF3 may be a potential target for the treatment of metastatic breast cancer.

[Glucose and lipid metabolic disorders in myasthenia gravis patients and its mechanisms]

Objective: To investigate the glucose and lipid metabolic disorders in patients with myasthenia gravis (MG) without glucocorticoid therapy, and the relationships between insulin, insulin resistance, muscle strength, serum levels of osteocalcin, 25-hydroxy vitamin D (25OHD) and glucose and lipid metabolism. Methods: A total of 102 MG patients [(40±11) years old, 43 males and 59 females] without glucocorticoid treatment were enrolled in this cross-sectional study. Height, weight and the handgrip of dominant hands were measured. Serum levels of fasting blood glucose (FBG), 2-hour postprandial blood glucose (2 h PBG), glycosylated hemoglobin (HbA1c), fasting insulin (FINS), 2-hour postprandial insulin (2 h PINS), total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and osteocalcin, 25OHD were detected. Insulin resistance was assessed using homeostasis model assessment of insulin resistance (HOMA-IR). Results: The proportion of impaired fasting glucose or impaired glucose tolerance, type 2 diabetes, dyslipidemia, hyperinsulinemia in male and female were 30.0%, 10.0%, 50.0%, 33.3% and 17.5%, 3.5%, 27.7%, 7.1%, respectively. Serum osteocalcin levels in male and female were 2.8 (1.7, 4.4) μg/L and 2.3 (1.3, 3.9) μg/L, respectively. And 25OHD levels in male and female were (93.5±34.9) nmol/L and (81.0±30.5) nmol/L, respectively. Handgrip of male and female was (37.0±9.4) kg and (20.5±6.3) kg. After adjusted for age, FINS (r=0.619, P<0.001), 2 h PINS (r=0.640, P<0.001), HOMA-IR (r=0.534, P<0.001) were positively correlated with 2 h PBG, and the handgrip was negatively correlated with TC (r=-0.486, P=0.026), LDL-C (r=-0.485, P=0.026) in male. FINS (r=0.352, P=0.008; r=0.300, P=0.026; r=0.646, P<0.001) and 2 h PINS (r=0.278, P=0.040; r=0.518, P<0.001; r=0.382, P=0.006) and HOMA-IR (r=0.695, P<0.001; r=0.583, P<0.001; r=0.818, P<0.001) were positively correlated with FBG, 2 h PBG, HbA1c, and the handgrip were negatively correlated with FBG (r=-0.424, P=0.016), 2 h PINS (r=-0.345, P=0.034) and positively correlated with HDL-C (r=0.389, P=0.037) in female. There was no association between osteocalcin, 25OHD and glucose and lipid metabolism. Multivariate linear regression analysis also found that there were significant relationships between handgrip, insulin, insulin resistance levels and glucose and lipid metabolic disorders. Conclusion: There was a high proportion of glucose and lipid metabolic disorders in MG patients without glucocorticoid treatment, and the mechanism may be related to insulin resistance induced by muscle weakness.

[Nitrogen Removal of Double-bacteria-layer System via PN/A Process]

Nitrification and anaerobic ammonia oxidation (ANAMMOX) sludge was acclimated via SBR and MBR reactors respectively, both of which were embedded with microbial immobilization technology and spliced together to construct a PN/A double-bacteria-layer system. A short-term experiment proved that ammonia-oxidizing bacteria (AOB) and ANAMMOX bacteria in the system played dominant roles separately in different stages, which maintained the acid-base balance and achieved efficient removal of NH₄⁺-N (98.8%). A long-term experiment showed that the PN/A double-bacteria-layer system improved the utilization of dissolved oxygen (DO) and enhanced the stability and nitrogen removal efficiency, with limited dissolved oxygen. The nitrogen removal efficiency of the PN/A double-bacteria-layer system remained stable at~80% when the influent NH₄⁺-N was 200 mg·L^-1 or 400 mg·L^-1 in the presence of 1.0 mg·L^-1 DO, whereas those of the control group were only 58.1% and 61.4%, respectively. When influent NH₄⁺-N and DO were 400 mg·L^-1 and 3.0 mg·L^-1, respectively, the PN/A double-bacteria-layer system achieved a nitrogen removal efficiency, nitrogen loading rate (NLR), and nitrogen removal rate (NRR) of 87.9%, 0.4 kg·(m³·d)^-1, and 12.8 mg·(g·h)^-1, respectively.

Entire functions sharing a small function with their two difference operators

In this article, we deduce a uniqueness result of entire functions that share a small entire function with their two difference operators, generalizing some previous theorems of (Farissi et al. in Complex Anal. Oper. Theory 10:1317-1327, 2015, Theorem 1.1) and (Chen and Li in Adv. Differ. Equ. 2014:311, 2014, Theorem 1.1) by omitting the assumption that the shared small entire function is periodic.

Effect of ammonia on methane production pathways and reaction rates in acetate-fed biogas processes

In order to understand the correlation between ammonia and methanogenesis metabolism, methane production pathways and their specific rates were studied at total ammonium nitrogen (TAN) concentrations of 0.14-9 g/L in three methanogenic sludges fed with acetate, at both mesophilic and thermophilic conditions. Results showed that high levels of TAN had significant inhibition on methanogenesis; this could, however, be recovered via syntrophic acetate oxidation (SAO) coupled with Hydrogenotrophic Methanogenesis (HM) performed by acetate oxidizing syntrophs or through Acetoclastic Methanogenesis (AM) catalyzed by Methanosarcinaceae, after a long lag phase >50 d. Free ammonia (NH₃) was the active component for this inhibition, of which 200 mg/L is suggested as the threshold for the pathway shift from AM to SAO-HM. Methane production rate via SAO-HM at TAN of 7-9 g/L was about 5-9-fold lower than that of AM at TAN of 0.14 g/L, which was also lower than the rate of AM pathway recovered at TAN of 7 g/L in the incubations with a French mesophilic inoculum. Thermophilic condition favored the establishment of the SAO-catalyzing microbial community, as indicated by the higher reaction rate and shorter lag phase. The operational strategy is thus suggested to be adjusted when NH₃ exceeds 200 mg/L.

Entire solutions of nonlinear differential-difference equations

In this paper, we describe the properties of entire solutions of a nonlinear differential-difference equation and a Fermat type equation, and improve several previous theorems greatly. In addition, we also deduce a uniqueness result for an entire function f(z) that shares a set with its shift \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$f(z+c)$$\end{document}f(z+c), which is a generalization of a result of Liu.

Investigation of the long-term patency of a transmural heparinized polycaprolactone and poly(D,L-lactic/glycolic acid) scaffold

BACKGROUND

The transmural biodegradable polycaprolactone/poly(D,L-lactic/glycolic acid) (PCL/PLGA) scaffold is a promising modality for diffuse coronary atherosclerosis cases that are not suitable for bypass grafting. The purpose of this study was to evaluate the long-term performance of the PCL/PLGA scaffold in vivo in the setting of polymer and heparin degradation.

MATERIALS AND METHODS

After mechanical drilling through the ventricular wall was performed in the whole ventricular wall, two scaffolds were implanted into the ventricular wall. Animals were grouped into the single drilling group (SD group), the blank scaffold group (BS group), and the heparinized scaffold group (HS group) and were allowed to survived for 6 mo. Next, the patency and integrity of the scaffolds were evaluated by echocardiography and 3D-DOCTOR software. Endothelium coverage of the lumen was evaluated by scanning electron microscopy. Neovessels and collagen fiber within the scaffolds were identified by histologic staining. Metabolite production of prostacyclin (PGI2) and thromboxane A2 (TXA2) in the plasma was measured by an enzyme-linked immunosorbent assay. The expression levels of PGI2 synthase and cyclooxygenase 2 (COX-2) involved in PGI2 production and COX-1 involved in TXA2 production were measured by Western blot analysis.

RESULTS

The heparinized scaffolds were patent for up to 6 mo and the lumen was covered with confluent endothelial cells. Histologic staining revealed collagen fiber remodeling and reconstruction of the neovascular network immediately surrounding the lumen. The expression of PGI2 synthase and COX-2 in the HS group was significantly higher compared with the SD and BS groups (P < 0.01). The expression of COX-1 was similar in the three groups (P > 0.05). Consistent with synthetase expression, a PGI2 metabolite (6-keto-PGF1a) also showed a significant increase in the HS group relative to the SD and BS groups (P = 0.021 and P = 0.015, respectively). Concomitantly, as a PGI2 antagonist, the TXA2 metabolite (TXB2) did not exhibit a significant difference among the three groups (P = 0.17).

CONCLUSIONS

Despite polymer and heparin degradation, the scaffold could continuously maintain the structural integrity and lumen patency for up to 6 mo by reinforcement of host collagen fiber and the balance of PGI2/TXA2.

The combined effect of bacteria and Chlorella vulgaris on the treatment of municipal wastewaters

Impacts of Chlorella vulgaris with or without co-existing bacteria on the removal of nitrogen, phosphorus and organic matter from wastewaters were studied by comparing the wastewater treatment effects between an algae-bacteria consortium and a stand-alone algae system. In the algae-bacteria system, C.vulgaris played a dominant role in the removal of nitrogen and phosphorus, while bacteria removed most of the organic matter from the wastewater. When treating unsterilized wastewater, bacteria were found to inhibit the growth of algae at >231 mg/L dissolved organic carbon (DOC). Using the algae-bacteria consortium resulted in the removal of 97% NH4(+), 98% phosphorus and 26% DOC at a total nitrogen (TN) level of 29-174 mg/L. The reaction rate constant (k) values in sterilized and unsterilized wastewaters were 2.17 and 1.92 mg NH4(+)-N/(mg algal cell ·d), respectively.

Comparison of different fluorescence spectrum analysis techniques to characterize humification levels of waste-derived dissolved organic matter

In the present work, the humification level of waste-derived dissolved organic matter (DOM) at different waste biostability was investigated, by using fluorescent excitation-emission matrix (EEM) scanning. Different fluorescence spectrum analysis techniques were applied and compared. Experimental results demonstrate that parallel factor (PARAFAC) analysis was sensitive to reflect DOM humification, and the most reasonable to deconstruct DOM compositions, when compared with other spectrum analysis techniques. It suggests applying the DOM-EEM-PARAFAC pipeline for rapid estimation of waste biostability.

[Study on moxa sticks burning temperature-time-space curves]

OBJECTIVE

To study the burning characteristics of moxa stick.

METHODS

A self-designed moxa stick burning temperature measuring device, which was assembled with ALTEC intelligence digital setter and SJ-600 thermocouple, was used to conduct next four experiences: 1) embedding a thermocouple inside a moxa stick to measure peak burning temperature; 2) pulling a thermocouple embedded in the moxa stick at the proper rate to detect combustion stability; 3) elucidating temperature distribution of transverse section by measuring the temperature in the center, radius midpoint and lateral; 4) drawing temperature-time-space curves by pulling the thermocouples in the former three observation points.

RESULTS

The experiment indicated that the burning temperature peak of three-year moxa stick (Hubei Herbal Medicine St. Qichun Technology Co., Ltd.) was 848 degrees C which had good combustion stability. Furthermore, the temperature in the center, radius midpoint and lateral of transverse section were 843 degrees C, 731 degrees C and 410 degrees C, respectively, and its burning temperature-time-space curves was drawn, which showed the real-time burning temperature and the peak burning temperature and were regarded as ultimate indice to integrate the formers.

CONCLUSION

The measuring system elaborately reflecting the burning features of moxa stick may provide reference for manufacture industry of moxa stick quality criteria for its convenience and accuracy.

[Clinical outcome of patients undergoing emergent coronary artery bypass grafting following failed percutaneous coronary intervention in stent era]

OBJECTIVE

To explore clinical outcomes of patients undergoing emergent coronary artery bypass grafting (CABG) following failed percutaneous coronary intervention (PCI) in the stent era.

METHODS

Eleven patients who underwent emergent CABG following failed PCI from January, 2002 to December 2010 were enrolled. The in-hospital follow-up included cardiac deaths, Q-wave myocardial infarction, kidney failure, and cerebrovascular events. The clinical end-point of out-hospital follow-up was the major adverse cardiac events including death, myocardial infarction, and target lesion revascularization.

RESULTS

The patients were (61 ± 5) years old. Coronary angiography showed 5 patients had triple vessel lesions. There were 9 target lesions on left anterior descending artery. There were 3 (27.3%) severe calcified, 4 (36.4%) chronic total occlusion, and 4 (36.4%) diffused long lesions. Reasons for emergent CABG were dissection (n = 5, 45.5%), perforation (n = 3, 27.3%), failure to sufficient predilation (n = 1, 9.1%), acute closure (n = 1, 9.1%) and stent loss (n = 1, 9.1%). The average duration of follow-up was (47 ± 33) months. During in-hospital follow-up, there were 1 (9.1%) cardiac death and 2 (18.2%) Q wave myocardial infarction. During follow-up after hospital discharge, 1 patient (9.1%) died of kidney failure, and there was no rehospitalization due to cardiac events.

CONCLUSIONS

Emergent CABG after failed PCI often happened in patients with complex coronary lesions. The long term outcome of patients requiring emergent CABG after failed PCI was favorable in this cohort.

Transmyocardial drilling revascularization combined with heparinized bFGF-incorporating stent activates resident cardiac stem cells via SDF-1/CXCR4 axis

OBJECTIVE

To investigate whether transmyocardial drilling revascularization combined with heparinized basic fibroblast growth factor (bFGF)-incorporating degradable stent implantation (TMDRSI) can promote myocardial regeneration after acute myocardial infarction (AMI).

METHODS

A model of AMI was generated by ligating the mid-third of left anterior descending artery (LAD) of miniswine. After 6 h, the animals were divided into none-treatment (control) group (n=6) and TMDRSI group (n=6). For TMDRSI group, two channels with 3.5 mm in diameter were established by a self-made drill in the AMI region, into which a stent was implanted. Expression of stromal cell-derived factor-1(α) (SDF-1(α)) and CXC chemokine receptor 4 (CXCR4), cardiac stem cell (CSC)-mediated myocardial regeneration, myocardial apoptosis, myocardial viability, and cardiac function were assessed at various time-points.

RESULTS

Six weeks after the operation, CSCs were found to have differentiated into cardiomyocytes to repair the infarcted myocardium, and all above indices showed much improvement in the TMDRSI group compared with the control group (P<0.001).

CONCLUSIONS

The new method has shown to be capable of promoting CSCs proliferation and differentiation into cardiomyocytes through activating the SDF-1/CXCR4 axis, while inhibiting myocardial apoptosis, thereby enhancing myocardial regeneration following AMI and improving cardiac function. This may provide a new strategy for myocardial regeneration following AMI.

Heparin- and basic fibroblast growth factor-incorporated degradable stent: comparison with traditional transmyocardial revascularization

AIM

We have recently developed a novel method transmyocardial drilling revascularization (TMDR) combined with heparinized bFGF-incorporating degradable tubular stent implantation to revascularize ischemic myocardium. The aim of the present study was to compare the effect of this new method on left ventricular (LV) remodeling and global function to traditional transmyocardial revascularization (TMR) in acute myocardial ischemia.

METHODS

Eighteen miniswine underwent ligation of the left anterior descending (LAD) at the mid-third and were divided into three groups (N.=6 in each group): no treatment (control), TMDR (T), and TMDR+stent implantation (TS) groups. Two channels with 3.5 mm in diameter were established (T and TS groups), followed by implantation of two stents (TS group). LV function, myocardial perfusion, expression of von Willebrand factor (vWF), transforming growth factor-β3 (TGF-β3), vascular endothelial growth factor (VEGF), interleukin-1beta (IL-1β), vascular density, and histologic and morphologic analyses were evaluated at different time-points.

RESULTS

Six weeks post-treatment, there were no differences between T and control groups. TS group showed significant improvement compared to T group as to: expressions of TGF-β3, VEGF, vWF and IL-1β (P<0.001), neovascular density (2.561±391 vs. 6.201±443 pixels/hpf, P<0.001), myocardial viability (18.913±2775 vs. 94.800±14.076 pixels/hpf, P<0.001), and dp/dtmax (1.735±161 vs. 2.242±223 mmHg/s, P<0.001), Further, there were significant decreases in changes of Mass Defect Percent (2.05±0.22% vs. -1.79±0.45%, P<0.001) and LV end diastolic volume (164.83±10.74 vs. 147.00±7.32 mL, P=0.048) in the TS group.

CONCLUSION

TMDR and stent implantation is more effective in enhancement of myocardial viability, improvement of global LV function, and attenuation of LV remodeling than TMDR.

Size-dependence of Magnetic Properties of Bismuth Ferrite Nanopowders

A series of BiFeO3 nanopowders were prepared by the sol-gel process. X-ray diffraction analysis shows that their rhombohedral crystal symmetry remains unchanged. However, as the particle size decreases, the edge length of the unit cell increases markedly and the angle between the edges deviates increasingly from 60°. Magnetic measurements show obvious weak ferromagnetism. The magnetization and magnetic susceptibility increase with decreasing particle size. Mössbauer studies reveal that the spin canting angles in the smaller particles are bigger and have a wider distribution. The magnetic structure in these particles is a complicated uncompensated antiferromagnetic spin arrangement.

[Correlation between the spontaneous clearance of HBV DNA and the levels of alanine aminotransferase in chronic hepatitis B]

OBJECTIVE

To investigate the correlation between spontaneous clearance of HBV DNA and the levels of Alanine Aminotransferase (ALT) in chronic hepatitis B (CHB) patients.

METHODS

Retrospective review analysis was used in this research. A total of 177 CHB patients with HBV DNA>1x10(4) copies/ml and ALT>800 U/L were recruited in this study and were divided randomly into two groups, 84 patients in control group (received lamivudine therapy) while 96 cases in study group (without anti-viral therapy), the dynamic changes of HBV DNA and HBV markers in these two groups were compared.

RESULTS

The clinical data of CHB patients were retrospected and followed up in 24 weeks. The negative conversion cases of HBV DNA are 62 (87.3%) in study group and 56 cases (78.87%) in control group at week 24, the negative conversion cases of HBV DNA are 56 (78.9%) in study group and 60 (92.3%) cases in control at week 8. No significant difference (x2=0.058, P>0.05) existed between these two groups. Among 43 patients with HBV DNA is less than or equal to 6 log10 copies/ml, 41 (95.3%) patients converted negatively, while in 28 patients with HBV DNA is more than 6 log10 copies/ml, 21 (75.0%) patients converted negatively. The negative conversion rate of HBV DNA is more than 6 log10 copies/ml was lower than the other group at week 24. The difference between the two groups was significant (x2=0.024, P<0.05). 41 patients with hepatitis B e antigen (HBeAg) negative and 30 patients with HBeAg positive were included in antiviral group. The negative conversion cases of HBV DNA of the former are 36 (87.8%) and the latter are 26 (86.7%). No significant difference found between them (x2=1, P>0.05). HBeAg loss found in 10 patients of 30 HBeAg positive patients with 4 patients occurred as early as at the fourth week. A total of 62 patients HBV DNA converted negatively in antiviral group, but 5 patients were found HBV DNA rebounded (occurred in 24 to 72 weeks) with ALT rebound (47 to 140 U/L).

CONCLUSIONS

The tendency of spontaneous clearance of HBV DNA when ALT is more than 800 U/L is obvious, so anti-viral therapy should be administrated strictly. The negative conversion rate of HBV DNA has no relation with HBeAg but with the copies of HBV DNA replication.

Mechanisms of the protective effects of BMSCs promoted by TMDR with heparinized bFGF-incorporated stent in pig model of acute myocardial ischemia

This study investigates the mechanism by which transmyocardial drilling revascularization combined with heparinized basic fibroblast growth factor incorporated degradable stent implantation (TMDRSI) enhanced effects of bone marrow mesenchymal stem cells (BMSCs) transplantation against acute ischemic myocardial injury. After the mid-third of left anterior descending artery was ligated, miniswine were divided into none-treatment group (control, n = 6), BMSCs implantation group (C, n = 6), TMDRSI group (TS, n = 6) and TMDRSI and BMSCs implantation group (TSC, n = 6). Two channels of 3.5 mm diameter were established by a self-made drill in the ischemic region, into which a stent was implanted for the TS and TSC groups. Autologous BMSCs were transplanted into the ischemic region in C group or around the channels in TSC group. Expression of von Willebrand factor, vascular endothelial growth factor, interleukin-1β, transforming growth factor-β₃, cell proliferation and apoptosis, histological and morphological analyses, myocardial remodelling and cardiac function were evaluated at different time-points. Six weeks after the operation, the above indices were significantly improved in TSC group compared with others (P < 0.05), though C and TS groups also showed better results than the control group (P < 0.05). The new method was shown to have activated paracrine pathway of transplanted BMSCs, increased survival and differentiation of such cells, and enhanced effects of BMSCs transplantation on myocardial remodelling, which may provide a new strategy for cell therapies against acute ischemic myocardial injury.

[Value of estimated glomerular filtration rate and serum creatinine for predicting long-term survival in Chinese patients after isolated coronary artery bypass graft surgery]

OBJECTIVE

To compare the predictive value of glomerular filtration rate (GFR) estimated by the Cockcroft-Gault formula or the modification of diet in renal disease (MDRD) equation and serum creatinine for in-hospital and long-term mortality post coronary artery bypass graft surgery (CABG).

METHODS

Clinical data of 5559 consecutive patients undergoing isolated CABG were retrospectively analyzed. The main outcomes were in-hospital mortality and long-term mortality. Estimated GFR was calculated by the Cockcroft-Gault formula and MDRD equation respectively. Receiver-operating characteristic curves and Cox's analysis were used for the comparison.

RESULTS

Follow-up was complete in 5485 patients (97.6%). Analysis of receiver-operating characteristic curves showed that GFR estimated by the Cockcroft-Gault formula had a maximal accuracy for predicting in-hospital mortality (area under the curve: 0.755, P < 0.01). Multivariate logistic analysis and the Cox's analysis results indicated estimated GFR < 60 mlxmin(-1)x1.73 m(-2) base on the Cockcroft-Gault formula was an independent risk factor for in-hospital and long-term mortality (hazard ratio 4.51 for in-hospital mortality, P < 0.01; hazard ratio 1.54 for long-term mortality, P < 0.01), both Cockcroft-Gault formula and MDRD equation were superior to serum creatinine for predicting in-hospital and long-term mortality post CABG.

CONCLUSION

GFR estimated by the Cockcroft-Gault formula was superior to GFR estimated by the MDRD equation for predicting in-hospital mortality, and estimated GFR was superior to serum creatinine for predicting in-hospital and long-term mortality.

[Estimated glomerular filtration rate as a risk factor for long-term survival in Chinese renal insufficiency patients after isolated coronary artery bypass graft surgery]

OBJECTIVE

To investigate the eGFR as a risk factor for long-term (4-year) outcome in Chinese renal insufficiency patients after isolated coronary artery bypass grafting (CABG) at our institution.

METHODS

From January 1999 to September 2003, 3371 consecutive patients who underwent isolated CABG were retrospectively reviewed. Of these patients, 549 (16.29%) patients were female, 1979 (58.71%) patients with hypertension, 866 (25.69%) patients with diabetes, 1130 (33.52%) patients with hyperlipidemia, 1011 (29.99%) patients with left main stenosis > 50%, and 1150 (34.11%) patients undergoing off-pump procedures. The mean age was (60 +/- 9) years old. Estimated GFR was calculated using the Cockcroft-Gault formula. The main outcomes were in-hospital mortality, in-hospital morbidity and long-term mortality. COX analysis was used in this study.

RESULTS

There were 649 patients with glomerular filtration rate estimates < 60 ml/(min.1.73 m(2)) and 2722 patients with glomerular filtration rate estimates > 60 ml/(min.1.73 m(2)). The in-hospital mortality and follow-up mortality was higher in the estimated glomerular filtration rate < 60 ml/(min.1.73 m(2)) group (2.77% vs. 0.77%, P < 0.01), (6.81% vs. 2.63%, P < 0.01). The COX analysis result confirmed eGFR < 60 ml/(min.1.73 m(2)), derived using the Cockcroft-Gault formula (HR: 1.948, 95%CI: 1.357 to 2.797, P < 0.01) was an independent risk factor for long-term mortality in patients after coronary artery bypass grafting surgery.

CONCLUSIONS

The estimated glomerular filtration rate < 60 ml/(min.1.73 m(2)) derived using the Cockcroft-Gault formula is an independent risk factor for long-term mortality in patients after coronary artery bypass grafting surgery.

A new transmyocardial degradable stent combined with growth factor, heparin, and stem cells in acute myocardial infarction

AIMS

We developed a new method-transmyocardial drilling revascularization (TMDR) with absorbable stent incorporated with basic fibroblast growth factor (bFGF) and heparin. The present study tested the effect of this method with transplantation of bone marrow-derived stem cells (BMSCs) in acute myocardial infarction.

METHODS AND RESULTS

Infarction was produced in mini-swine by ligating the left anterior descending (LAD) coronary artery. TMDR of 3.0 mm in diameter was made by mechanical drilling in the infarcted area. The animals that had LAD ligation were divided into six groups according to the procedures followed (n = 6 in each): control; T (TMDR); C (cell implantation); TS (TMDR+stent implantation); TC (TMDR+cell implantation); TSC (TMDR+stent implantation+cell implantation). Left ventricular (LV) function, myocardial perfusion, vascular density, and histological and morphological analyses were evaluated pre-operatively and at 30 min and 6 weeks post-operatively. Six weeks after operation, the above indices were significantly better in the TSC group than in other groups (P < 0.001 compared with the control group, and P < 0.05 or 0.01 compared with the TS and TC groups), although TS and TC also showed better results than the control group (P < 0.05).

CONCLUSION

We have demonstrated in a pig model that an intramyocardial stent implanted with slow release of bFGF, heparin, and BMSC transplantation may significantly increase LV function, cardiac blood flow, and vascular density. Therefore, the present study may provide a new method for the surgical treatment of myocardial infarction.

[Preparation of a biodegradable drug-eluting stent in myocardium channel]

OBJECTIVE

To prepare a biodegradable drug-eluting stent in myocardium channel and evaluate its effect on myocardium channel after transmyocardial revascularization (TMR).

METHODS

A biodegradable drug-eluting stent was prepared using poly (epsilon-caprolactone) (PCL), bovine serum albumin (BSA), and poly (D, L-lactide-co-glycolide) (PLGA) as material of stent, model protein drug, and drug carrier respectively. The amount of BSA in stent and in vitro released BSA of stent were determined by the Coomassie brilliant blue assay. The mechanical strength of stent was tested by universal material testing machines. The material and structure of stent was characterized by nuclear magnetic resonance spectroscopy. The effect of stent on myocardium channel after TMR was evaluated in vivo by a standard animal model of chronic myocardial ischemia in miniswine.

RESULTS

The stent could carry 13.1 microg BSA per mg of stent and the stent could release about 95% of BSA after 30 days. The stent diminished 80% of initial scale under the stress of 1.7 Mpa. It also kept the myocardium channel patency after TMR.

CONCLUSIONS

A biodegradable drug-eluting stent in myocardium channel was successfully prepared. It can sustain the pressure from the heart and achieve the controlled release of drug. The stent can ensure the myocardium channel patency after TMR.

Impact of recycled effluent on the hydrolysis during anaerobic digestion of vegetable and flower waste

Two trials were established to investigate the effect of recycled effluent on hydrolysis during anaerobic co-digestion of vegetable and flower waste. Trial I evaluated the effect by regulating the flow rate of recycled effluent, while Trial II regulated the ratio of hydrolytic effluent to methanogenic effluent, which were recycled to hydrolysis reactor. Results showed that the recirculation of methanogenic effluent could enhance the buffer capability and operation stability of hydrolysis reactor. Higher recycled flow rate was favourable for microbial anabolism and further promoted hydrolysis. After 9 days of hydrolysis, the cumulative SCOD in the hydrolytic effluent reached 334, 407, 413, 581 mg/g at recycled flow rates of 0.1, 0.5, 1.0, 2.0 m3/(m3 x d), respectively. It was feasible to recycling a mixture of hydrolytic and methanogenic effluent to the hydrolysis reactor. This research showed that partially introducing hydrolytic effluent into the recycled liquid could enhance hydrolysis, while excessive recirculation of hydrolytic effluent will inhibit the hydrolysis. The flow ratio 1:3 of hydrolytic to methanogenic effluent was found to provide the highest hydrolysis efficiency and degradation rate of lignocelluloses-type biomass, among four ratios of 0:1, 1:3, 1:1 and 3:1. Under this regime, after 9 days of hydrolysis, the cumulative TOC and TN in the hydrolytic effluent reached 162 mg/g and 15 mg/g, the removal efficiency of TS, VS, C and cellulose in the solid phase were 60.66%, 62.88%, 58.35% and 49.12%, respectively. The flow ratio affected fermentation pathways, i.e. lower ratio favoured propionic acid fermentation and the generation of lactic acid while higher ratio promoted butyric acid fermentation.

Bacterial community dynamics and product distribution during pH-adjusted fermentation of vegetable wastes

AIMS

To estimate the effect of pH on the structures of bacterial community during fermentation of vegetable wastes and to investigate the relationship between bacterial community dynamics and product distribution.

METHODS AND RESULTS

The bacterial communities in five batch tests controlled at different pH values [uncontrolled (about pH 4), 5, 6, 7 and 8] were monitored by denaturing gradient gel electrophoresis (DGGE) and single-strand conformation polymorphism (SSCP). The two fingerprinting methods provided consistent results and principal component analysis indicated a close similarity of bacterial community at pH 7 and 8 in addition to those at pH 4-6. This clustering also corresponded to dominant metabolic pathway. Thus, pH 7-8 shifted from alcohol-forming to acid-forming, especially butyric acid, whereas both alcohol-forming and acid-forming dominated at pH 5-6, and at pH 4, fermentation was inhibited. Shannon-weaver index was calculated to analyse the DGGE profiles, which revealed that the bacterial diversities at pH 7 and 8 were the highest while those at pH 5 and 4 (uncontrolled) were the lowest. According to sequencing results of the bands excised from DGGE gels, lactic acid bacteria and Clostridium sp. were predominant at all pH values, but varieties in species were observed as pH changed and time prolonged.

CONCLUSIONS

The bacterial community during fermentation was materially influenced by pH and the diverse product distribution was related to the shift of different bacterial population.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study reveals that the impact of pH on fermentation product distribution is implemented primarily by changes of bacterial community. It also provides information about the comparison of two fingerprinting methods, DGGE and SSCP.

[Preparation and evaluation of microbubble ultrasound contrast agent with N-carboxymethyl chitosan]

OBJECTIVE

To prepare microbubble, made of N-carboxymethyl chitosan, as ultrasound contrast agent and evaluate its characteristics and acoustic effects in vivo.

METHODS

Oil-Water-Oil multiple emulsion/solvent evaporation method was used to prepare the microbubble contrast agent. Both optical micrography and scanning electron micrography were performed to determine the bubble size and morphology. The acoustic effect of the N-carboxymethyl chitosan echo contrast agent was evaluated in vivo in rabbit. Liver echo images were recorded with ultrasound machine before and after intravenous bolus injecting 0.5 ml of the agent.

RESULTS

The novel N-carboxymethyl chitosan echo contrast agent was formulated as lyophilized product, with a mean diameter of 2-3 microm and a shell thickness of 250-300 nm. Its size is relatively uniform. The imaging effect was remarkably enhanced with the ultrasonic contrast agent when applied in rabbit livers.

CONCLUSION

It is feasible to prepare excellent microbubble ultrasound contrast agent with N-carboxymethyl chitosan as membrane components.

Effect of alkali metal cation on the anaerobic hydrolysis and acidogenesis of vegetable waste

Five batch testing scenarios were designed to evaluate the effects of alkali metal cations on anaerobic hydrolysis and acidogenesis. These scenarios were A (c=0 g l(-1)), B (cNa+=25 g l(-1)), C (cNa+=50 g l(-1)), D (cK+=25 g l(-1)), and E (cK+=50 g l(-1), pH 7.0). A solution pH of 7.0 or above favored protein hydrolysis, higher proteinase activity and higher ammonia production. However, such a pH suppressed carbohydrate hydrolysis, as indicated by low alpha-amylase activity. Cation interference at pH 5.0-6.0 seemed not to affect carbohydrate hydrolysis, as showed by the unimpaired alpha-amylase activity at 50 g l(-1) K+. Acidogenesis was more sensitive to alkali metal cations, so acid production and the drop in pH were lowest in a 25-50 g l(-1) Na+, acidic environment (pH 4.0-6.0). It was insensitive to cations when the pH was maintained at 7.0-8.0. When the pH was uncontrolled and decreased freely to acidic values, 25 g l(-1) of cation inhibited the action of the microbes, which rapidly acclimated, as presented by the slow transformation of soluble polymers to soluble metabolites. However, acidogenetic microbes could not easily recover from inhibition by 50 g l(-1) of cation. When the pH was maintained at over 7.0, the microbes were not inhibited by cation (50 g l(-1)) as indicated by the more active acidogenesis. The metabolic pathways to lactate, acetate and alcohols were not fully coupled.

[Clinical diagnosis and treatment of acquired immunodeficiency syndrome complicated by tuberculosis]

OBJECTIVE

To explore the clinical characteristics and method of therapy of acquired immunodeficiency syndrome (AIDS) patients complicated by tuberculosis.

METHOD

10 cases suffered from AIDS complicated by tuberculosis from 1995 to 2000 were analyzed.

RESULTS

(1) Clinical type: of the 10 cases, hematogenous disseminated tuberculosis with cerebral tuberculosis in 3, tuberculous lymphadenitis in 4 (in which one was in mesentery, one in mediastinum and neck, 2 in neck), primary pulmonary tuberculosis in 3, with other opportunistic infections, such as Pneumocystis carinii pneumonia (PCP). (2) Immunological and tuberculin test: in all 10 cases, CD4+ cells were (2 - 87) x 10(6)/L, of them 7 cases CD4+ cells less than 50 x 10(6)/L, mean CD4+ (33 +/- 13) x 10(6)/L. Tuberculin tests were negative. (3) TREATMENT: 5 cases were treated with anti-tuberculosis and highly active anti-retrovirus treatment (HAART), the others were treated with anti-tuberculosis only. Six months later, comparing with anti-tuberculosis, CD4+ cells in patients of anti-tuberculosis with HAART increased significantly (P < 0.05, respectively).

CONCLUSIONS

The decrease of CD4+ cell might be important in AIDS with tuberculosis. Tuberculin test is not a good way of diagnosing AIDS with tuberculosis. Among AIDS complicated by tuberculosis, hematogenous disseminated tuberculosis and extra-pulmonary tuberculosis are common and usually combined with other various opportunistic infections, clinical manifestations are complex and treatment should be prolonged. This combined treatment can shorten treating time and improve the prognosis of AIDS with tuberculosis.

[Expression and clinical significance of p53 protein and p21(WAF1) in non-small-cell lung carcinoma]

OBJECTIVE

To investigate the relationships between expression of tumor suppressor gene p53 protein, p21(WAF1), clinicopathology and prognosis in human non-small-cell lung carcinoma (NSCLC).

METHODS

SP immunohistochemistry performed in all cases.

RESULTS

One hundred forty-seven resected NSCLC were examined. There were 63 squamous cell carcinomas, 66 adenocarcinomas, 14 adenosquamous carcinomas and 4 large cell carcinomas. Overall 90 (61.2%) of the 147 cases had positive p53 staining. The positive ratios of p53 overexpression of squamous cell carcinomas, adenocarcinomas, adenosquamous carcinomas and large cell carcinomas were 63.5% (40/63), 57.6% (38/66), 71.4% (10/14) and 50% (2/4) respectively. The average positive ratio of p21(WAF1) expression was 40.1% (59/147) in lung carcinoma. The positive ratios of p21(WAF1) expression of squamous cell carcinomas, adenocarcinomas, adenosquamous carcinomas and large cell carcinomas were 41.3% (26/63), 42.4% (28/66), 28.6% (4/14) and 25% (1/4) respectively. Over expression of p53 protein was associated with prognosis of the patients with adenocarcinomas. The positive ratio of p53 expression in over 3 year survival patients was 75% (21/28) and in less than 3 year survival, 44.7% (17/38) (P < 0.025). The positive expression of p21(WAF1) was related to prognosis of NSCLC. The ratio of 3-year survival (64.4%) in p21(WAF1) positive NSCLC was much higher than in p21(WAF1) negative patients (46.6%) (P < 0.05). Prognosis of patients with p53 positive but p21(WAF1) negative expression was poorer than those with p53 negative and p21(WAF1) positive NSCLC (P < 0.01).

CONCLUSION

These findings suggest that over expression of p53 in adenocarcinomas could be used as a prognostic factor for patients. p21(WAF1) is of protein has a definite value in judging the prognosis in NSCLC. Combined expression of p53 and p21(WAF1) can be used as the prognostic markers in NSCLC and are of significance in estimating the prognosis of patients.

[Analysis of the clinical characteristics and the pathology of large cell lung cancer]

OBJECTIVE

To study the clinical characteristics and the pathology of large cell lung cancer (LCLC).

METHODS

Comparing the microscopic and immunohistochemical findings with clinical data by analyzing 54 cases of surgically treated LCLC from 1978 to 1997.

RESULTS

There were 6 cases of clear cell carcinoma and one case of giant cell carcinoma in 54 cases. Male:female was 5:1(45/9). LCLC accounted for 1.28% of all surgically treated lung cancers. The average survival time was 23 months. The positive rate of P53 protein expression was 65%(13/20). The positive rate of PCNA staining was 100%(20/20).

CONCLUSIONS

LCLC may be divided into squamous type, adenomatous type, neuroendocrine type and undifferentiated type.

[Pathologic review of 5,050 pulmonary tuberculosis cases]

OBJECTIVE

To summarize the pathomorphologic changes of pulmonary tuberculosis and the relationship between those changes and the combined chemotherapy regimens.

METHODS

Observing the pathological changes in 5,050 cases with pulmonary tuberculosis, and the relationship between three different combined chemotherapy regimens HSP, HRS, HRZS and the pathological changes of pulmonary and bronchial tuberculosis.

RESULTS

The rate of surgical excision of caseous cavities and fibrous-cavities declined markedly in cases treated by HRS and HRZS regimens (P < 0.01). Whereas, after treated by HSP, HRS and HRZS regimens, the rate of surgical excision of tuberculoma were 26.82% (897/3,345), 41.24% (464/1,125) and 47.8% (277/580) respectively which showed a rising tendency (P < 0.01). Open healing cavities were found in 42 patients.

CONCLUSIONS

The effects of combined rifampicin and pyrazinamide chemotherapy caused the changing of pathologic types of pulmonary tuberculosis, that is: the increased proportion of tuberculoma and the decreased proportion of caseous and fibrous cavities. Tuberculoma ought to be taken into account in the classification of tuberculosis.

Proglucagon gene expression is induced by gastrin-releasing peptide in a mouse enteroendocrine cell line

The proglucagon gene is expressed in a cell-specific manner in the A cells of the islets and the L cells of the intestine; however, the physiological factors that regulate proglucagon gene expression are not well understood. Although insulin inhibits proglucagon gene transcription in the islets, peptides that stimulate proglucagon gene expression have not been identified. We show here that gastrin-releasing peptide (GRP) induces proglucagon messenger RNA transcripts in STC-1 enteroendocrine cells. The GRP induction of proglucagon gene expression was dose dependent, detectable by 4 h after GRP treatment, and sustained, i.e. detectable after a 24-h GRP incubation. GRP also induced the transcriptional activity of rat proglucagon promoter-luciferase plasmids in transfected STC-1 cells. The GRP induction of proglucagon promoter activity was attenuated, but not eliminated, after deletion of 5'-flanking sequences containing the proglucagon gene cAMP response element (CRE). A mutation in the CRE previously shown to abrogate cAMP responsiveness and CRE-binding protein binding was associated with a reduction in the transcriptional response to GRP. The proglucagon CRE also conferred GRP responsiveness to a truncated proglucagon promoter in STC-1 cells. These observations identify GRP as a peptide activator of proglucagon gene expression and provide evidence linking the proglucagon gene CRE to the physiological control of proglucagon gene expression.

[Basic study on evaluation of the fundus with monochromatic photography]

By using the monochromatic fundus photographic system we developed, fundus pictures of 93 normal subjects were taken under the illumination of 10 lights with varying wavelengths. A densitometer was used for evaluating these photographic results. Optimal illumination lights were selected respectively for photography of different layers of fundus details. The results showed that the degrees of contrast at the macula, optic nerve fiber layer, physiological cup of papilla, retinal artery and vein, optic nerve head, choroid striae are the highest under the illumination of light with wavelength 478nm, 478nm, 530nm, 570nm, 628nm and 628nm respectively. The visibility of nerve fiber layer in the subjects over 50 years old is the highest under the illumination of light with a wavelength of 530nm. However, the degrees of contrast of all their fundus structural details, especially the macula and nerve fiber layer, are lower than those of subjects under 50 years old photographed with the corresponding lights with optimal wavelengths (P < 0.01).

Expression, distribution, regulation and function of IGFs in the ovine fetal pituitary

Activation of the fetal pituitary-adrenal axis is crucial for fetal organ maturation and the onset of parturition in sheep. Many factors including corticotrophin-releasing hormone (CRH) and arginine vasopressin secreted from the hypothalamus, and growth factors produced within the pituitary may be involved in the regulation of maturation of the fetal pituitary gland. IGFs have mitogenic and differentiation-promoting capacities in a variety of organs and are synthesized as paracrine factors within developing tissues. However, there is little information concerning the synthesis, distribution, regulation and function of IGFs in the fetal pituitary gland at different times during pregnancy. Therefore, we have localized IGF-I and IGF-II mRNAs and peptides, and determined the effect of cortisol on the level of IGF-II mRNAs in the pituitary glands of developing sheep fetuses. We examined the possible effects of IGFs on corticotroph function in cultures of adenohypophysial cells from term fetuses. Seven species of IGF-II transcripts of 1.2-6.0 kb were identified by Northern blot analysis in the pituitary gland of fetuses between day 60 of gestation and term (day 145). The levels of IGF-II mRNAs did not change significantly during pregnancy, although there was a trend for the presence of higher levels of IGF-II mRNAs at day 60 of gestation. IGF-I mRNA was not detectable. By in situ hybridization, IGF-II mRNA was localized to non-endocrine cells and to cells lining the blood vessels of the pars distalis, to some presumed endocrine cells in the pars distalis and pars intermedia, and to clusters of cells in the pars nervosa. In contrast, IGF-I and IGF-II peptides were detected in the presumed endocrine cells in the pars distalis and pars intermedia but not in the pars nervosa. Incubation of adenohypophysial cells from term fetuses with IGF-I, but not IGF-II, for 48 h increased specific 125I-Tyr-ovine CRH binding. However, neither IGF-I nor IGF-II had any significant effects on the basal or CRH-stimulated immunoreactive (ir)-ACTH output, the level of POMC mRNA or the number of ir-ACTH positive cells. Infusion of cortisol to fetuses starting at day 96 of gestation for 100 h or at days 120-125 of gestation for 84 h did not affect the level of IGF-II mRNAs in the pars distalis but decreased the levels of POMC mRNA. These results are consistent with IGFs having the potential to influence fetal pituitary function, although probably on cell types other than the corticotrophs.(ABSTRACT TRUNCATED AT 400 WORDS)

Regulation of ovine fetal pituitary function by corticotrophin-releasing hormone, arginine vasopressin and cortisol in vitro

Parturition and fetal organ maturation in sheep are associated with increased activity of the fetal hypothalamic-pituitary-adrenal (HPA) axis during late pregnancy. However, the factors responsible for HPA activation remain unclear. In the fetal pituitary, levels of pro-opiomelanocortin (POMC) mRNA increase, but the numbers of binding sites for corticotrophin-releasing hormone (CRH), and ACTH responsiveness to exogenous CRH decline during the last 20 days of pregnancy. We have examined regulation of CRH binding, pituitary ACTH responsiveness, and levels of POMC mRNA in cultures of adenohypophysial cells from term fetal sheep. After a 4-day stabilization period, output of immunoreactive (ir) ACTH was increased over 48 h in a dose-dependent fashion by both CRH and arginine vasopressin (AVP) but decreased by cortisol. Subsequent output of ir-ACTH to a 3-h challenge with 100 nM CRH was attenuated after pretreatments with CRH, AVP or cortisol; the effect of CRH being greater than that of cortisol or AVP. At the end of 48 h of treatment with CRH, AVP or cortisol, there was a 40-50% reduction in the number of CRH-binding sites, but the levels of POMC mRNA decreased significantly only after cortisol treatment and were not altered significantly by CRH or AVP. We conclude that under the conditions of these experiments, CRH and AVP increase ir-ACTH output without increasing the level of steady-state POMC mRNA, but may contribute to loss of pituitary responsiveness to CRH by down-regulation of CRH receptor number. Cortisol exerts negative feedback on POMC mRNA and decreases the number of CRH receptors. Thus, any one or all of CRH, AVP and cortisol could be responsible for the decline in CRH binding in the fetal sheep pituitary during late pregnancy. Although CRH and AVP may affect secretion of ir-ACTH, the present results do not support a role for these neuropeptides in affecting the level of POMC mRNA in the fetal sheep pituitary.

Regulation of insulin-like growth factor-II gene expression in the ovine fetal adrenal gland by adrenocorticotropic hormone and cortisol

Maturation and activation of the fetal adrenal gland is crucial to fetal organ maturation and the onset of parturition in sheep. Insulin-like growth factors (IGFs) have been demonstrated to promote fetal adrenal mitogenesis and steroidogenesis in some species. Our previous studies showed that IGF-II mRNA is expressed in the steroidogenic cells of the fetal sheep adrenal, suggesting that IGF-II may be an important regulator of fetal adrenal function. However, the regulation of IGF-II gene expression is poorly understood. In the present study we measured the changes in IGF-II mRNA level in fetal sheep adrenals during late gestation in response to ACTH and cortisol. Either saline (0.5 ml/h) or cortisol (1 mg/24 h) was infused for 100 h to fetal sheep beginning on day 95 or 96 of pregnancy, or saline (0.5 ml/h), ACTH (0.5 micrograms/h) or cortisol (1 mg/h) was infused for 84 h to fetal sheep beginning on days 120-125 of pregnancy (term = 145 days). Adrenal RNA was subjected to Northern blot analysis with an ovine IGF-II cDNA probe. The relative abundance of total IGF-II mRNA decreased significantly in the ACTH- and cortisol-treated fetuses. IGF-II mRNA was localized by in situ hybridization using a 35S-labeled antisense ovine IGF-II cRNA probe, and IGF-II peptide was localized by immunohistochemistry. There were no differences in the cellular distribution patterns of IGF-II mRNA and IGF-II peptide after treatments, but the intensity of the hybridization signal for IGF-II mRNA and of immunostaining for IGF-II peptide decreased in adrenals from fetuses treated with ACTH or cortisol. These results suggest that ACTH and cortisol decrease IGF-II gene expression in the ovine fetal adrenal. We speculate that the cortisol surge observed in the late gestation ovine fetus may be responsible for down-regulation of IGF-II gene expression in the fetal adrenal at or just before birth.

[Effects of 6,7-dimethoxycoumarin on experimental arrhythmia]

By using the arrhythmic animal models, the effect of 6,7-dimethoxycoumarin (DMOC) on arrhythmia was investigated. The arrhythmia in anaesthetized rat were induced by iv aconitine 20 micrograms.kg-1 or CaCl2 5 mg.kg-1. The arrhythmia in anesthetized guinea pigs was induced by iv ouabain 3.6 micrograms.kg-1.min-1. Procainamide (PA) was used as a positive control. DMOC (33-500 mg.kg-1, ig) and PA (100-800 mg.kg-1, ig) in anaesthetized rats could delay the time of onset of arrhythmia induced by aconitine. The ED50 of DMOC and PA for postponing the occurrence of ventricular extrasystole (VE) were 88 mg.kg-1 (95% confidence interval was 43-165 mg.kg-1) and 183 mg.kg-1 (95% confidence interval was 109-304 mg.kg-1), respectively. The results suggested that the anti-arrhythmia potency of DMOC was higher than that of PA (P < 0.01).

Characteristics and developmental changes of corticotrophin-releasing hormone-binding sites in the fetal sheep anterior pituitary gland

The responses of the fetal sheep pituitary to corticotrophin-releasing hormone (CRH) change during gestation with maximum output of ACTH around days 120-130, and decreased ACTH output near term. However, there is no information available concerning the extent to which these responses may be modulated by alterations in the number of CRH receptors. Therefore we measured specific CRH-binding sites, and changes in binding characteristics in membrane preparations from fetal sheep anterior pituitaries collected at days 65-70, 85-88, 100-110, 125-130 and at term (approximately 145 days). Binding assays were carried out using 125I-labelled Tyr-ovine CRH (125I-Tyr-oCRH), incubated with crude membrane fractions for 90 min at 22 degrees C. Binding was time- and temperature-dependent, linear with protein concentration, saturable and specific for oCRH. Scatchard analysis of binding data for individual tissues revealed a single class of CRH-binding sites with high affinity (Kd congruent to 1 nmol/l) that did not change significantly with gestational age. However, the number of CRH-binding sites increased progressively from days 65-70 to a maximum at days 125-130, then decreased at term. These results demonstrate the presence of specific CRH-binding sites in the fetal sheep anterior pituitary. Furthermore, the change in CRH receptor number with advancing pregnancy follows a similar time-course to the changes reported previously in responsiveness of the fetal sheep anterior pituitary to exogenous CRH stimulation in vivo. These results suggest that alterations in CRH receptor number may contribute to changes in responsiveness of the fetal sheep anterior pituitary to CRH during gestation.