Silibinin protects β cells from glucotoxicity through regulation of the Insig-1/SREBP-1c pathway

Exposure to high glucose may cause glucotoxicity, leading to pancreatic β cell dysfunction including cell apoptosis, impaired glucose‑stimulated insulin secretion (GSIS) and intracellular lipid accumulation. Sterol regulatory element binding protein-1c (SREBP-1c), a key nuclear transcription factor that regulates lipid metabolism, has been proven to play a role in insulin secretion. Insulin induced gene-1 (Insig-1) is an upstream regulatory factor of SREBP-1c. The overexpression of Insig-1 significantly inhibits SREBP-1c expression and thereby blocks the expression of downstream genes. It has been proven that silibinin, a natural flavanone, is involved in a variety of biological functions. In the present study, we examined whether silibinin protects high glucose-induced β cell dysfunction through the Insig-1/SREBP-1c pathway. Our data demonstrated that 30.0 µM of silibinin significantly improved cell viability (P<0.05) after rat insulinoma INS-1 cells were exposed to high glucose for 72 h. Silibinin partially attenuated GSIS following exposure to high glucose for either 24 or 72 h (both P<0.05). As shown by reverse transcription quantitative PCR, silibinin upregulated the mRNA expression of insulin secretion‑related genes [insulin receptor substrate 2 (IRS-2), pancreatic and duodenal homeobox 1 (PDX-1) and insulin], but downregulated uncoupling protein‑2 (UCP-2) expression. Silibinin inhibited intracellular lipid accumulation and free fatty acid (FFA) synthesis. Further experiments revealed that silibinin improved β cell function through the regulation of the Insig-1/SREBP-1c pathway. In conclusion, these results clearly suggest that the protection of β cells from glucotoxicity can be significantly enhanced through the regulation of the Insig-1/SREBP-1c pathway. Thus, silibinin may be a novel therapeutic agent for β cell dysfunction.

[Effect of GLP-1 on high glucose-induced human umbilical vein endothelial cell apoptosis and mechanism]

OBJECTIVE

To investigate the effects of glucagon-like peptide-1 (GLP-1) on high glucose-induced apoptosis of human umbilical vein endothelial cells (HUVECs) and the mechanism involved.

METHODS

HUVECs were cultured under varying conditions for 48 h, and the cell viability was spectrophotometrically measured by MTT assay. Flow cytometry detected the ratio of cell apoptosis. Western blot detected the protein levels of p-Akt and p-eNOS, while NO assay kit detected the NO concentration.

RESULTS

Treatment of high glucose (33 mmol/L) for 48 h significantly decreased the HUVECs viability and induced the apoptosis of HUVECs, concomitant with decreased Akt and eNOS phosphorylation leves and subsequent NO production. Treatment with GLP-1 (3 nmol/L) for 48 h in the high glucose group increased the HUVECs viability (P<0.01), decreased the ratio of HUVECs early apoptosis (P<0.05), ameliorated the reduced protein levels of p-Akt and p-eNOS caused by high glucose, and increased the NO production (P<0.05). The anti-apoptotic effect and the increased NO production of GLP-1were inhibited by PI3K inhibitor wortmannine (100 nmol/L) or eNOS inhibitor L-NAME (100 μmol/L). The effect on p-Akt, p-eNOS of GLP-1 was inhibited by wortmannine (100 nmol/L) while L-NAME (100 μmol/L) did not have any influence on the expression of p-Akt.

CONCLUSION

GLP-1 can ameliorate high glucose-induced HUVECs apoptosis, which is probably related to the up-regulation of PI3K/Akt/eNOS pathway.

Relationship between the preoperative body mass index and the improvement of glycolipid metabolism in Chinese type 2 diabetic patients after Roux-en-Y gastric bypass

BACKGROUND/AIMS

Roux-en-Y gastric bypass (RYGB) is a gastrointestinal operation for type 2 diabetic patients could significantly alleviate or even achieve complete cure with long-term maintenance. The purpose of this study was to investigate the interrelationship between the initial BMI and the postoperative improvement of glucose and lipid metabolism in Chinese type 2 diabetic patients undergoing RYGB.

METHODOLOGY

Retrospective analysis of a consecutive series of cases, stratified by preoperative BMI into three groups (group A, 20kg/m2≤ BMI <25kg/m2; group B, 25kg/m2 ≤BMI <30kg/m2; and group C, 30kg/m2≤ BMI <35kg/m2). RYGB was used for thirty type 2 diabetic patients. Glycometabolism and lipid metabolism indexes were detected before and 12 months after surgery.

RESULTS

None of the pre- and postoperative indicators of glycolipid metabolism were significantly different among the three groups. Compared to preoperative indicators, postoperative glycolipid metabolism improved in each group, especially in group B. Overall, glycemic resolution occurred in 23.3% of patients, glycemic control in 43.4% and glycemic improvement in 33.3%. Preoperatively, all groups exhibited similar high percentages of abnormal glucose metabolism indicators, and there was a significant reduction in each group postoperatively, especially in group B. These patients presented with the highest percentage of preoperative triglycerides, cholesterol and LDL. Group C had the highest percentage of preoperative abnormal HDL. Postoperatively, all groups showed a significant reduction in the percentages of abnormal lipid metabolism indicators.

CONCLUSIONS

There are significant resolutions of glycolipid metabolism in all the three groups after RYGB. Furthermore, group B is superior to group A and group C in the improvement of glycolipid metabolism in Chinese type 2 diabetic patients.

[Visfatin level after laparoscopic Roux-en-Y gastric bypass surgery in patients with Type 2 diabetes]

OBJECTIVE

To investigate the change in serum visfatin level after laparoscopic Roux-en-Y gastric bypass surgery in patients with Type 2 diabetes mellitus (T2DM) and to explore the relationship between visfatin insulin resistance and diabetes.

METHODS

Thirty-three patients with Type 2 diabetes were studied before and after the gastric bypass surgery. The level of fasting serum visfatin was measured by enzyme-linked immunosorbent assay. Fasting plasma glucose (FPG), glycated hemoglobin (HbA1c) and fasting insulin (FINS) were measured before and after the gastric bypass surgery.

RESULTS

Compared with before the operation, the indicators of HbA1c, FINS, and insulin resistance index (HOMA-IR) were decreased after the laparoscopic Roux-en-Y gastric bypass surgery. The body mass index (BMI) [(24.53 ± 0.62) kg/m² vs (26.71 ± 0.69) kg/m2] was decreased, with significant difference (P<0.001). The serum visfatin level [(9.79 ± 0.64) ng/mL] was significantly lower than before the operation [(38.24 ± 5.32) ng/mL], with significant difference (P<0.001).

CONCLUSION

Serum level of visfatin is decreased in T2DM patients who undergo gastric bypass surgry, reflecting an improvement in insulin resistance and diabetes.

Effect of laparoscopic Roux-en-Y gastroenterostomy with BMI<35 kg/m(2) in type 2 diabetes mellitus

BACKGROUND

Roux-en-Y gastric bypass (RGB) has been endorsed by the "First World Congress on International Therapies for Type 2 diabetes" as a possible therapeutic option in patients with type 2 diabetes with a body mass index (BMI) of less than 35 kg/m(2). In the present study, we assessed the improvement in clinical indicators associated with laparoscopic Roux-en-Y gastric bypass (LRYGB) in patients with non-obese type 2 diabetes mellitus (T2DM).

METHODS

LRYGB was performed in 30 T2DM patients with a BMI <35 kg/m(2). The patients were followed up for 1 year. Pre- and postoperative changes in BMI, waist circumference, and biochemical indicators including fasting plasma glucose and glycosylated hemoglobin were recorded.

RESULTS

Significant reduction in glycosylated hemoglobin from 8.02 ± 1.77 to 5.59 ± 1.02 % (p < 0.05) at 12 months was noted. Diabetes was completely resolved in nine cases, resulting in discontinuation of diabetes-related medication. No significant surgical complications occurred.

CONCLUSIONS

LRYGB is beneficial for non-obese T2DM patients in China.

A clinical trial of xenotransplantation of neonatal pig islets for diabetic patients

OBJECTIVE

To ascertain the safety and function of the transplantation of neonatal pig islets (NPIs) for diabetic patients.

METHODS

NPIs were injected into the hepatic artery of 22 patients. After the transplantation, the patients were treated with a multiple drug immunosuppressive regimens. The first 14 patients were treated with cyclosporine (CsA), mycophenolate mofetil (MMF) and prednisolon, and porcine C-peptide was not monitored, the following 2 patients were given cyklosporin and MMF only, while the next 6 patients were given a quadruple drug regimen consisting of OKT3, takrolimus, sirolimus and prednisolon. The blood glucose levels,exogenous insulin requirement,HbA1c, porcine endogenous retrovirus (PERV) and liver function were assessed before and after NPI transplantation. The serum porcine C peptide were monitored in last 8 patients.

RESULTS

The first 14 patients required less insulin and the HbA1c dropped after the transplantation. In the 2 subsequent patients, the metabolic parameters remained unchanged and monitor of porcine C-peptide was negative. Insulin requirements were reduced in all 6 patients, and HbA1c was normalized 3 months after the transplantation. Significant levels of porcine C-peptide were detected in the patient serum. Two of the patients were given a second injection of NPIs, and one of them became insulin independent for 7 d. No serious adverse events were noted after the transplantation. There was no evidence of PERV transmission. Six out of the 22 patients were followed up for 4-6 years after the NPIs injection, immunosuppressive treatment was stopped 1 year after the transplantation. The patients started to take insulin at the time of follow up. Four patients restricted the intake of sugar, while the other 2 did not. One patient had ketoacidosis twice and slight diabetic retinopathy, and another patient had ketoacidosis induced by acute gastroenteritis. The remaining 4 patients did not have any complications. Assays for PERV were again negative.

CONCLUSION

Xenogenic islets can survive and function in the human body. No serious adverse events are noted.

Changes in Adipokines following Laparoscopic Roux-en-Y Gastric Bypass Surgery in Chinese Individuals with Type 2 Diabetes Mellitus and BMI of 22-30 kg·m(-2.)

Aims. Although altered endocrine changes following bariatric surgery in morbidly obese patients with diabetes have been demonstrated by previous studies, little is known about their effects on low BMI patients of T2DM. We investigated the changes in adipokines and sICAM-1 in Chinese subjects with low BMI and T2DM after LRYGB and explored their relationship with postsurgical insulin sensitivity. Methods. Plasma levels of adiponectin, sICAM-1, fasting glucose, glycated hemoglobin, and fasting insulin and serum levels of visfatin were measured before and at three months after LRYGB in 33 T2DM patients with BMI of 22-30 kg·m(-2). Results. Significant reductions in anthropometric measurements and indicators of glucose and lipid metabolism and moderate reductions in insulin resistance and fasting insulin were observed at three months after LRYGB. Postoperative adiponectin level (P < 0.001) was increased compared to the preoperative level, whereas visfatin (P < 0.001) and sICAM-1 (P < 0.001) were lower than that before surgery. Serum adiponectin negatively correlated with HOMA-IR and FIns both preoperatively and at three months after surgery, and visfatin positively correlated with HOMA-IR and FIns both preoperatively and postoperatively. Conclusion. Changes in adipokines were related to an improvement in postsurgical insulin sensitivity, which was predicted by weight loss after LRYGB even in low BMI patients with T2DM.

Enhanced healing of diabetic wounds by subcutaneous administration of human umbilical cord derived stem cells and their conditioned media

Objective. Mesenchymal stem cells (MSCs) isolated from the umbilical cord and their conditioned media (CM) can be easily obtained and refined compared with stem cells from other sources. Here, we explore the possibility of the benefits of these cells in healing diabetic wounds. Methodology and Results. Delayed wound healing animal models were established by making a standard wound on the dorsum of eighteen db/db mice, which were divided into three groups with six mice in each: groups I, II, and III received PBS, UC-MSC, and CM, respectively. UC-MSC and their CM significantly accelerated wound closure compared to PBS-treated wounds, and it was most rapid in CM-injected wounds. In day-14 wounds, significant difference in capillary densities among the three groups was noted (n = 6; P < 0.05), and higher levels of VEGF, PDGF, and KGF expression in the CM- and UC-MSC-injected wounds compared to the PBS-treated wounds were seen. The expression levels of PDGF- β and KGF were higher in CM-treated wounds than those in UC-MSC-treated wounds. Conclusion. Both the transplantation of UC-MSC and their CM are beneficial to diabetic wound healing, and CM has been shown to be therapeutically better than UC-MSC, at least in the context of diabetic wound healing.

Formononetin-induced apoptosis of human prostate cancer cells through ERK1/2 mitogen-activated protein kinase inactivation

Formononetin is a main active component of red clover plants (Trifolium pratense L.), and is considered as a phytoestrogen. Our previous studies demonstrated that formononetin caused cell cycle arrest at the G0/G1 phase by inactivating insulin-like growth factor 1(IGF1)/IGF1R-phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway in MCF-7 cells. In the present study, we investigated the molecular mechanisms involved in the effect of formononetin on prostate cancer cells. Our results suggested that higher concentrations of formononetin inhibited the proliferation of prostate cancer cells (LNCaP and PC-3), while the most striking effect was observed in LNCaP cells. We further found that formononetin inactivated extracellular signal-regulated kinase1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) signaling pathway in a dose-dependent manner, which resulted in increased the expression levels of BCL2-associated X (Bax) mRNA and protein, and induced apoptosis in LNCaP cells. Thus, we concluded that the induced apoptosis effect of formononetin on human prostate cancer cells was related to ERK1/2 MAPK-Bax pathway. Considering that red clover plants were widely used clinically, our results provided the foundation for future development of different concentrations formononetin for treatment of prostate cancer.

Effect of erythropoietin on the proliferation and apoptosis of neonatal porcine islet cells

OBJECTIVE

To investigate the effect of erythropoietin on the proliferation,differentiation, and apoptosis of the cultured neonatal porcine islet cells in vitro.

METHODS

Neonatal porcine islet cells were separated and pured from neonatal pigs with collagenase digestion and tissue culture, and their viability and purity were tested. The neonatal porcine islet cells were divided into a control group and an experimental group.The experimental group was treated with erythropoietin but not the control group, and the insulin secretion responsiveness induced by low and high glucose stimulation in the islet was tested after 5 days. Cells were counted and the activation of amplification was determined by MTT chromatometry. The rates of cell apoptosis were observed by ethidium bromide/acridine orange (EB/AO) of fluorescent light staining and flow cytometry, and the cell cycle was analyzed by flow cytometry. The expression of bcl-2, bax, caspase-3, glucose transporter 2 (GlUT-2), and pancreatic duodenal homeobox-1 (PDX-1) mRNA was tested by RT-PCR.

RESULTS

After erythropoietin was treated in the cell culture, the neonatal porcine islet cells had normal morphology, function, and reaction of insulin secretion to the glucose stimulation. Cell count showed more cells in the experimental group than in the control group (P<0.05). MTT chromatometry showed the optical absorbance tended to increase with time, and compared with the control group, the optical absorbance was higher in the experimental group (P<0.05), the expression of PDX-1 mRNA was slightly up-regulated (P<0.05). The expression of GLUT-2 mRNA had no difference in the 2 groups (P=0.34). In the experimental group, the apoptisis rate was lower than that in the control group by flow cytometry and EB/AO fluoscence staining (P<0.01), and the expression of bcl-2 mRNA was higher. Howerer bax mRNA and caspase-3 mRNA were obviously lower than those in the control group (P<0.01).

CONCLUSION

Erythropoietin can promote the proliferation but has no effect on the function of neonatal porcine islet cells in vitro. Erythropoietin can protect neonatal porcine islet cells from apoptosis through up-regulating bcl-2 mRNA and downreguling bax and caspase-3 mRNA.

[Effect of glucagon like peptide-1 on proliferation and differentiation of endothelial progenitor cells and its mechanism]

OBJECTIVE

To investigate the effect and mechanism of glucagon like peptide 1(GLP-1)on the proliferation and differentiation of endothelial progenitor cells(EPCs)derived from the peripheral blood.

METHODS

Mononuclear cells were isolated from human peripheral blood by density gradient centrifugation. After 7 days of culture,attached cells were stimulated with different cultures of 0.2% BSA,and GLP-1(1,10,and 20 nmol/L). Laser scanning confocal microscope was used to determine the EPCs from human peripheral blood.The activity of EPCs was observed under reverse microscope. MTT was used to determine the proliferation of EPCs. The expression of KDR,Flt-1,VE-cadherin,and eNOS mRNA was detected by RT-PCR.The concentration of serum VEGF was detected by ELISA. The expression of VEGF protein was detected by immunohistochemical SP method. The EPCs cultured in GLP-1 were intervened by VEGFmAb.

RESULTS

EPCs was proliferated more in the GLP-1 group(1,10,and 20 nmol/L) than in the control group (P<0.05 or P<0.01). The expression of KDR,FLT-1,VE-cadherin,eNOS mRNA and VEGF protein was higher than that in the control group(P<0.05 or P<0.01). VEGFmAb(100 ng/mL)down-regulated the expression of KDR,Flt-1,VE-cadherin,and eNOS mRNA.

CONCLUSION

GLP-1 can promote the proliferation and differentiation of EPCs derived from the peripheral blood by up-regulating VEGF autocrine.

Multiple symmetric lipomatosis: substantial subcutaneous adipose tissue accumulation did not induce glucose and lipid metabolism dysfunction

OBJECTIVE

To study whether substantial subcutaneous adipose tissue (SCAT) can induce glucose and lipid metabolism dysfunction and possible underlying mechanisms.

METHODS

We report a male patient with multiple symmetrical lipomatosis (MSL) suffering from increased adipose tissue accumulation in abdomen and back for 7 years, accompanied by the gradual expansion of excess adipose tissue to the nuchal region, upper thorax, upper arms and shoulders. Four obese male adults of similar age and body mass index were chosen as controls (only 4 subjects consented to blood and tissue sampling).Blood samples were collected before anesthesia in the early morning after overnight fasting, and tissue samples from all subjects and the patient were obtained under general anesthesia. Glucose tolerance, insulin resistance in the oral glucose tolerance test and insulin-releasing test were studied. A pathologic examination was made and expression of SCAT-related genes was determined.

RESULTS

Although adipose tissue mainly accumulated in SCAT, the patient had no impaired glucose tolerance, insulin resistance and dyslipidemia. Importantly, the circulating adiponectin concentration was higher than in the control group (50.3 +/- 3.2 vs. 28.4 +/- 2.2 microg/ml, p < 0.05). Accordingly, adiponectin and leptin mRNA expression in SCAT was higher than in the control group (1.83 and 3.75 times, p < 0.05) but TNF-alpha and IL-6 mRNA levels were lower (decreased by 79 and 45%, p < 0.05). Furthermore, pathologically, adipocyte size in the patient's SCAT was smaller than in the control group (66.2 +/- 6.1 vs. 78.9 +/- 6.6 and 98.6 +/- 12.8 microm in SCAT and omentum adipose tissue, respectively, p < 0.05).

CONCLUSION

In spite of the patient's SCAT accumulation, glucose and lipid metabolism dysfunction was absent. The mechanism may involve the interaction of different factors, including the subcutaneous formation of small adipocytes, the secretion of protective adipokines such as adiponectin and anti-inflammatory effects of SCAT.

Cetuximab-based therapy vs noncetuximab therapy in advanced or metastatic colorectal cancer: a meta-analysis of seven randomized controlled trials

PURPOSE

A meta-analysis was performed to assess the efficacy and safety of cetuximab-based therapy vs noncetuximab therapy in advanced or metastatic colorectal cancer.

METHOD

A total of 4617 patients from seven randomized controlled trials were available for analysis, with 2305 patients in the cetuximab group and 2312 patients in the noncetuximab group. The efficacy data included progression-free survival (PFS), overall survival (OS) and overall response rate (ORR). The safety data that contained overall grade 3 and 4 adverse events (AEs), specific grade 3 and 4 toxicity such as acneiform rash, cetuximab-related skin toxicity, diarrhoea, fatigue, neutropenia, hypertension, nausea and hand-foot skin reaction are evaluated.

RESULT

There was a significant PFS benefit in favour of cetuximab-based therapy (HR = 0.68, 95%CI: 0.63 to 0.73) and OS benefit (HR = 0.90, 95%CI: 0.81 to 1.00). The ORR was significantly higher in the cetuximab-based arm (OR = 2.19, 95% CI: 1.30 to 3.68). The incidence of overall grade 3-4 toxicity was significantly higher in the cetuximab arm compared with the noncetuximab arm (61.2%vs 43.0%, OR = 2.32, 95%CI: 1.59-3.39). This difference was mainly attributed to cetuximab-related skin toxicity (OR = 5.86, 95%CI: 1.38-24.88), especially acneiform rash (OR = 51.37, 95%CI: 22.75-116.02). In addition, cetuximab resulted in a significant increase in grade 3 and 4 diarrhoea, fatigue and neutropenia, except for hypertension, nausea and hand-foot skin reaction.

CONCLUSION

Cetuximab-based therapy improves PFS and OS resulting in better ORR vs noncetuximab therapy. Its most common and severe AE is skin toxicity that should be predictable and manageable.

Capecitabine plus oxaliplatin vs fluorouracil plus oxaliplatin as first line treatment for metastatic colorectal caner - meta-analysis of six randomized trials

OBJECTIVE

This meta-analysis was performed to evaluate the efficacy and safety of capecitabine plus oxaliplatin vs fluorouracil (FU) plus oxaliplatin as first line treatment for metastatic or advanced colorectal cancer.

METHOD

A total of 2196 patients from six randomized controlled trials were available for analysis, which included 1105 patients in capecitabine plus oxaliplatin group and 1091 patients in FU plus oxaliplatin group. The efficacy data included overall survival (OS), progression-free survival (PFS), time to treatment failure (TTF), overall response rate (ORR), and the safety data contained specific grade 3 and 4 toxicity such as anaemia, thrombocytopenia, neutropenia, diarrhoea, nausea, asthenia, vomiting, abdominal pain, hand foot syndrome, neuropathy and stomatitis were evaluated.

RESULTS

Pooled analysis of OS (hazards ratio HR = 1.04, 95%CI: 0.95-1.14), PFS (1.08, 0.98-1.18), ORR (odds ratio OR = 0.87, 0.73-1.03) in the capecitabine plus oxaliplatin group shows no statistical significance when compared with those in the FU plus oxaliplatin group. The statistically significant differences in pooled estimates suggest a higher incidence of grade 3/4 thrombocytopenia (OR = 1.87, 1.24-2.81), grade 3/4 hand-foot syndrome (3.90, 2.13-7.12) in the capecitabine plus oxaliplatin group and grade 3/4 neutropenia (0.20, 0.07-0.53) in the FU plus oxaliplatin group. No statistically significant difference was noted in the incidence of grade 3/4 anaemia, asthenia, diarrhoea, nausea, vomiting, abdominal pain, neuropathy and stomatitis.

CONCLUSION

The effect of capecitabine plus oxaliplatin regimen is similar to FU plus oxaliplatin regimen as first line treatment for metastatic colorectal cancer, but it offers advantages of simplicity and convenience to administer.

The effect of aspirin in the recurrence of colorectal adenomas: a meta-analysis of randomized controlled trials

PURPOSE

Colorectal adenomas are precursors of most colorectal cancers and are important targets for chemoprevention. Aspirin is thought to play an important role in chemoprevention. However, the role of aspirin in preventing recurrence of adenomas is controversial. We performed a systematic review and meta-analysis to evaluate the effect of aspirin in preventing the recurrence of colorectal adenoma.

METHOD

Trials were located through Medline, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL). From 14 articles screened, three were identified as randomized controlled trials and were included for data extraction. Main outcome measures were the recurrence of any new adenoma and advanced adenoma. The meta-analysis was performed with the fixed-effects model.

RESULTS

A total of 2338 participants were enrolled in the three studies and 2175 of them completed the follow-up colonoscopy. We found that the relative risks of any adenoma (when compared with the placebo group) were 0.859 in the high dose of aspirin groups (95% confidence interval (CI), 0.756-0.976, P = 0.019), 0.826 in the low dose of aspirin groups (95% CI 0.706-0.965, P = 0.016) and 0.836 in the both aspirin combined groups (95% CI 0.746-0.937, P = 0.002). For the recurrence of advanced adenoma, the relative risk (when compared with the placebo group) was 0.655 (95% CI 0.513-0.837, P = 0.001) in the aspirin groups without considering the dose.

CONCLUSION

This meta-analysis suggests that aspirin prevents recurrent colorectal adenomas among patients with a history of colorectal adenomas.

Meta-analysis of endoscopic submucosal dissection versus endoscopic mucosal resection for tumors of the gastrointestinal tract

BACKGROUND AND STUDY AIMS

Endoscopic submucosal dissection (ESD) has been developed to overcome the limitations of endoscopic mucosal resection (EMR). We aimed to compare the outcomes of these two methods.

METHODS

Databases, including Pubmed, EMBASE, and The Cochrane Library, were searched to identify studies comparing ESD with EMR for premalignant and malignant lesions of the gastrointestinal tract. In a meta-analysis, primary end points were the en bloc resection rate and the curative resection rate; secondary end points were operation time, and rates of bleeding, perforation, and local recurrence.

RESULTS

15 nonrandomized studies (seven full-text and eight abstracts) were identified. Meta-analysis showed higher en bloc and curative resection rates (odds ratio [OR] 13.87, 95 %CI 10.12 - 18.99; OR 3.53, 95 %CI 2.57 - 4.84) irrespective of lesion size. Subgroup analysis showed higher en bloc and curative resection rates with ESD for esophageal, gastric, and colorectal neoplasms, and for lesions of size < 10 mm, 10 mm < 20 mm, and > 20 mm. Local recurrence was lower with ESD (OR 0.09, 95 %CI 0.04 - 0.18). But ESD was more time-consuming than EMR (weighted mean difference [WMD] 1.76; 95 %CI 0.60 - 2.92), and showed high procedure-related bleeding and perforation rates (OR 2.20, 95 %CI 1.58 - 3.07; OR 4.09, 95 %CI 2.47 - 6.80).

CONCLUSIONS

ESD showed better en bloc and curative resection rates and local recurrence compared with EMR, but was more time-consuming and had higher rates of bleeding and perforation complications. These results need to be confirmed by high quality trials and further studies in the west.

Meta-analysis of holmium laser enucleation versus transurethral resection of the prostate for symptomatic prostatic obstruction

BACKGROUND

Holmium laser enucleation (HoLEP) is an alternative to transurethral resection (TURP) of the prostate for symptomatic prostatic obstruction.

METHODS

Randomized controlled trials comparing HoLEP and TURP were identified systematically using Medline, Embase and The Cochrane Library. Primary outcomes were peak urinary flow rate (Qmax), postvoid residual volume, symptom score and quality of life. Secondary outcomes were duration of operation, hospital stay, blood loss, catheterization time and adverse events.

RESULTS

There was no statistically significant difference between HoLEP and TURP in terms of Qmax at 6 and 12 months' follow-up. HoLEP was associated with significantly less blood loss, a shorter catheterization time and a shorter hospital stay. TURP was associated with reduced operating time. The techniques were similar in terms of urethral stricture, stress incontinence, transfusion requirement and rate of reintervention.

CONCLUSION

HoLEP and TURP provide a similar improvement in Qmax. HoLEP, however, has several advantages over TURP, despite requiring more operating time. It is at least as safe as TURP in terms of adverse events.

Effect of Brn-3a deficiency on primary nociceptors in the trigeminal ganglion

Immunohistochemistry for substance P, somatostatin and vanilloid receptor subtype 1 as well as receptors for somatostatin and opioids was performed on the trigeminal ganglion in wild-type and Brn-3a knockout mice at postnatal day 0. In wild-type mice, the trigeminal ganglion contained abundant substance P-, vanilloid receptor subtype 1-, sst2A receptor- and delta-opioid receptor-immunoreactive neurons, while the ganglion had only a few mu-opioid receptor-immunoreactive neurons. The Brn-3a deficiency had an effect on the cell size but not the number of substance P-immunoreactive neurons. In knockout mice, the proportion of small immunoreactive neurons markedly increased and that of medium- to large-sized immunoreactive ones correspondingly decreased (mean +/- S.D. = 54.7 +/- 29.1 microm2, range = 10.9-220.8 microm2) compared to wild-type mice (mean +/- S.D. = 116.6 +/- 58.6 microm2, range = 27.3-400.7 microm2). As for vanilloid receptor subtype 1-immunoreactive neurons, the number and cell size was barely affected by the deficiency. On the other hand, the loss of Brn-3a caused a decrease in the number of sst2A receptor- or delta-opioid receptor-immunoreactive neurons (more than 95% reduction) and an increase in the number of mu-opioid receptor-immunoreactive neurons (9.3-fold increase). Somatostatin-immunoreactive neurons were not detected in the trigeminal ganglion of wild-type or mutant mice at postnatal day 0. The present study suggests that Brn-3a deficiency may have effects on the survival of trigeminal nociceptors and their expression of some neurochemical substances.

Effect of Brn-3a deficiency on parvalbumin-immunoreactive primary sensory neurons in the dorsal root ganglion

Immunohistochemistry for parvalbumin, a marker for primary proprioceptors, was performed on the dorsal root ganglion (DRG) of wildtype and knockout mice for Brn-3a at postnatal day 0 and embryonic day 18.5. The DRG contained many parvalbumin-immunoreactive (ir) neurons in wildtype (5.4%) and knockout mice (5.6%). Cell size analysis demonstrated that such neurons were mostly medium-sized to large in these mice. Therefore, it is unlikely that the survival of proprioceptors is dependent upon Brn-3a in the DRG. In the dorsal column and gray matter of the spinal cord of knockout mice, however, parvalbumin-ir nerve fibers were sparse compared to wildtype mice. The number of parvalbumin-ir varicosities around motoneurons decreased in the mutant. Thus, our data suggest that Brn-3a may play an important role in the central projection and terminal formation of DRG proprioceptors in the spinal cord.

The transportation, time-dependent distribution of heavy metals in paddy crops

Sixteen experimenmtal plots (5 m x 6 m = 30 m2) were designed with four different levels of heavy metals (HMs) concentration in soil. The concentrations of heavy metals in soils, and paddy plant during the different periods of growth were investigated. A relationship between the total HM content in plants and the HM level in soil was found for a wide range of concentrations. The exchangeable fraction of HMs extracted with 1 M MgCl2 solution according to Tessier's method increased correlation with the dosage of supplemented HMs, then decreased as time went on. The time-related variation of exchangeable HMs in soil demonstrated that the amount of effective HMs taken up by paddy differed at various growth phases. The amount of HMs accumulated in different parts of paddy followed the order of root > stem > grain, leaf. The transportation potential of the HMs in paddy in present study followed the order of Zn, Cr > Cd, Cu > Pb. The HM content in root, stem and leaf of paddy plant (dry weight) was low at time of seedling. The concentration in the root increased sharply at time of tillering, decreased thereafter. The concentrations in stem and leaf reached the highest at time of tillering, then decreased, while rose slightly at following time.

[Changes in calcium and magnesium levels of lymphocytes in patients with diabetes and hypertension]

To investigate the cellular basis linking non-insulin-dependent diabetes mellitus(NIDDM) and hypertension, we used the atomic absorption spectrometry to detect Ca2+ and Mg2+ levels of serum and lymphocytes in patients with the above diseases. The results were that serum Ca2+ and Mg2+ levels had no change, but lymphocyte Ca2+ level increased obviously and lymphocyte Mg2+ level decreased obviously in both diseases, compared with normal controls. There were no difference between hypertension and NIDDM with and without hypertension. Ca2+ and Mg2+ levels of lymphocytes in patients with hypertension correlated with the systolic pressure respectively(Ca2+, r = 0.4633, P < 0.05; Mg2+, r = -0.4412, P < 0.05), but their levels in patients with NIDDM were not correlated with the fasting blood glucose. The results suggest that there is an abnormal Ca2+ and Mg2+ metabolism in lymphocytes in patients with hypertension and NIDDM.

Effect of Brn-3a deficiency on parvalbumin-, calbindin D-28k-, calretinin- and calcitonin gene-related peptide-immunoreactive primary sensory neurons in the trigeminal ganglion

Immunohistochemistry for parvalbumin, calbindin D-28k, calretinin and calcitonin gene-related peptide (CGRP) was performed on the trigeminal ganglion and oro-facial tissues in Brn-3a wildtype and knockout mice at embryonic day 18.5 and postnatal day 0. In wildtype mice, the trigeminal ganglion contained abundant parvalbumin-, calbindin D-28k- and CGRP-immunoreactive neurons while the ganglion was almost devoid of calretinin-immunoreactive neurons. In Brn-3a knockout mice, a 63% decrease of parvalbumin-immunoreactive neurons was detected. In contrast, the absence of Brn-3a dramatically increased the number of calbindin D-28k-immunoreactive (3.5-fold increase) and calretinin-immunoreactive neurons (91-fold increase). The number of CGRP-immunoreactive neurons, however, was not altered by the Brn-3a deficiency. Cell size analysis indicated that loss of Brn-3a increased the proportions of small (<100 microm (2)) parvalbumin-, calbindin D-28k- and CGRP-immunoreactive neurons while it decreased those of large (>200 microm(2)) immunoreactive cells. Calretinin-immunoreactive neurons were either small or medium (100-200 microm (2)) in mutant mice. The oro-facial tissues contained parvalbumin-, calbindin D-28k- and CGRP-immunoreactive fibers, but not calretinin-immunoreactive ones in wildtype mice. In Brn-3a knockout mice, the number of parvalbumin-immunoreactive fibers markedly decreased in the infraorbital nerve and parvalbumin-immunoreactive endings disappeared in the vibrissa. In contrast, the number of calbindin D-28k-immunoreactive fibers increased significantly in the infraorbital and mental nerves. In addition, calbindin D-28k-immunoreactive endings appeared in the vibrissa. As well, some fibers showed calretinin-immunoreactivity in the infraorbital nerve of the mutant. However, no obvious change of CGRP-immunoreactive fibers was observed in the oro-facial region of knockout mice. Taken together, our data suggest that Brn-3a deficiency has effects on the expression of neurochemical substances in the trigeminal ganglion.

Effect of Brn-3a deficiency on nociceptors and low-threshold mechanoreceptors in the trigeminal ganglion

Immunohistochemistry for protein gene product 9.5 (PGP 9.5, a neuron specific protein) and vanilloid receptor 1-like receptor (VRL-1, a marker for medium-sized to large primary nociceptors) were used to assess the effects of Brn-3a deficiency on neuronal innervation of oral tissues and neurons of the trigeminal ganglion (TG). In the knockout mouse, the number of PGP 9.5-immunoreactive (-ir) nerve fibers decreased in the facial cutaneous and oral mucous epithelia, as well as the incisor and molar tooth germs. The reduction of PGP 9.5-ir Merkel endings was also observed in some vibrissae. No obvious change was detected in other tissues. Cell size analysis demonstrated that the proportion of small neurons markedly increased while that of medium-sized and large neurons significantly decreased in the TG of the mutant. Moreover, Brn-3a deficiency caused the disappearance of TG neurons which were immunoreactive for VRL-1. Together, our data suggest that nociceptors and low-threshold mechanoreceptors with medium-sized to large cell bodies may be sensitive to the loss of Brn-3a.

Short-term responses of Oryzias latipes (Pisces: Adrianichthyidae) and Macrobrachium nipponense (Crustacea: Palaemonidae) to municipal and pharmaceutical waste water in Beijing, China: survival, behaviour, biochemical biomarkers

Whole effluent toxicity was assessed for the fish Oryzias latipes and the prawn Macrobrachium nipponense for 18 h in a dilution series (0-66%) of the inflow and effluent of a municipal waste water treatment plant as well as waste water from a teramycin producing pharmaceutical industry, before, during and after a pilot laboratory purification process. The waste waters caused acute toxicity as measured by inhibition of light emission in the luminiscent bacterium Vibrio qingaiensis sp. nov. (Q67). EROD and aryl hydrocarbon hydroxylase activity in in vitro carp liver-cells showed a dose-dependent toxic response to the municipal waste water. Behavioural responses and time-to-death of fish and prawn, recorded online with the "Multispecies Freshwater Biomonitor" proved to be concentration- and time-dependent sensitive toxicity indicators in both types of waste water. Behaviour changed stepwise from normal activity to (increased or decreased) activity to more time spent on ventilation and finally to increased morbidity at higher concentration and time of exposure. The municipal waste water treatment plant managed to reduce toxicity to bacteria (Q67), prawn and fish. The pharmaceutical waste water treatment process still has to be improved, in order to reduce toxicity for fish and prawn.

[Regulation on the immunological effect of mogrosides in mice]

OBJECTIVE

To investigate the cellular immunological effect of mogrosides in mice.

METHODS

Mogrosides was administered to normal or CTX-induced immunosuppressive mice, and their macrophage function and T lymphocyte proliferation were detected.

RESULTS

Mogrosides could promote phagocytosis and T lymphocyte proliferation significantly in the CTX-induced immunosuppressive mice, but not in the normal mice.

CONCLUSION

The results suggested that mogrosides had certain up-regulation on cellular immunity in the CTX-induced immunosuppressive mice.

Monitoring priority pollutants in a sewage treatment process by dichloromethane extraction and triolein-semipermeable membrane device (SPMD)

Semipermeable membrane devices containing a neutral lipid triolein (triolein-SPMD) and conventional dichloromethane extraction were used to monitor the presence and concentrations of priority organic pollutants in a sewage treatment process in Beijing, China. Both samples gave similar information on the presence of target PCB congeners, PAHs, Organochlorine pesticides and substituted benzenes in sewage at all sites. After 20 days' sampling, the concentrations of contaminants in triolein of SPMD were much higher than those in dichloromethane extracts, which resulted in easier analysis, improved the detection limits, and increased the accuracy. Previous field mean sampling rates for SPMD were used to estimate concentrations of PCB congeners in sewage, which compared to their determined concentrations by dichloromethane extraction. The consistency and superiority of SPMD technology were proved for the detection of priority organic contaminants from sewage. Lower removal rates for PCB congeners and PAHs coincided with the persistence of them in environment. More attention should be paid to urban sewage treatment process adopting activated-sludge method, where priority organic pollutants might not be removed, even present higher concentrations after treatment.

The Ath5 proneural genes function upstream of Brn3 POU domain transcription factor genes to promote retinal ganglion cell development

During retinogenesis, the Xenopus basic helix-loop-helix transcription factor Xath5 has been shown to promote a ganglion cell fate. In the developing mouse and chicken retinas, gene targeting and overexpression studies have demonstrated critical roles for the Brn3 POU domain transcription factor genes in the promotion of ganglion cell differentiation. However, the genetic relationship between Ath5 and Brn3 genes is unknown. To understand the genetic regulatory network(s) that controls retinal ganglion cell development, we analyzed the relationship between Ath5 and Brn3 genes by using a gain-of-function approach in the chicken embryo. We found that during retinogenesis, the chicken Ath5 gene (Cath5) is expressed in retinal progenitors and in differentiating ganglion cells but is absent in terminally differentiated ganglion cells. Forced expression of both Cath5 and the mouse Ath5 gene (Math5) in retinal progenitors activates the expression of cBrn3c following central-to-peripheral and temporal-to-nasal gradients. As a result, similar to the Xath5 protein, both Cath5 and Math5 proteins have the ability to promote the development of ganglion cells. Moreover, we found that forced expression of all three Brn3 genes also can stimulate the expression of cBrn3c. We further found that Ath5 and Brn3 proteins are capable of transactivating a Brn3b promoter. Thus, these data suggest that the expression of cBrn3c in the chicken and Brn3b in the mouse is initially activated by Ath5 factors in newly generated ganglion cells and later maintained by a feedback loop of Brn3 factors in the differentiated ganglion cells.

Reduction of obesity, as induced by leptin, reverses endothelial dysfunction in obese (Lep(ob)) mice

Obesity is a major health care problem and is associated with significant cardiovascular morbidity. Leptin, a neuroendocrine hormone released by adipose tissue, is important in modulating obesity by signaling satiety and increasing metabolism. Moreover, leptin receptors are expressed on vascular endothelial cells (ECs) and mediate angiogenesis. We hypothesized that leptin may also play an important role in vasoregulation. We investigated vasoregulatory mechanisms in the leptin-deficient obese (ob/ob) mouse model and determined the influence of leptin replacement on endothelial-dependent vasorelaxant responses. The direct effect of leptin on EC nitric oxide (NO) production was also tested by using 4, 5-diaminofluorescein-2 diacetate staining and measurement of nitrate and nitrite concentrations. Vasoconstrictor responses to phenylephrine, norepinephrine, and U-46619 were markedly enhanced in aortic rings from ob/ob mice and were modulated by NO synthase inhibition. Vasorelaxant responses to ACh were markedly attenuated in mesenteric microvessels from ob/ob mice. Leptin replacement resulted in significant weight loss and reversal of the impaired endothelial-dependent vasorelaxant responses observed in ob/ob mice. Preincubation of ECs with leptin enhanced the release of NO production. Thus leptin-deficient ob/ob mice demonstrate marked abnormalities in vasoregulation, including impaired endothelial-dependent vasodilation, which is reversed by leptin replacement. These findings may be partially explained by the direct effect of leptin on endothelial NO production. These vascular abnormalities are similar to those observed in obese, diabetic, leptin-resistant humans. The ob/ob mouse may, therefore, be an excellent new model for the study of the cardiovascular effects of obesity.

Mechanism of antihypertensive effect of dietary potassium in experimental volume expanded hypertension in rats

Dietary potassium supplementation lowers blood pressure (BP) and attenuates complications in hypertensive subjects, particularly those with the low renin volume expanded (LRVE) variety. We and others have shown that the plasma level of a digitalis like substance (DLS) is elevated in this type of hypertension. We therefore, examined the effect of increases in dietary potassium on the plasma level of endogenous DLS, myocardial and renal Na+, K+-ATPase (NKA) activities, BP, and renal excretory function in reduced renal mass (RRM)-salt hypertension in the rat, a classical model of LRVE hypertension. 70% RRM rats were divided in 4 groups, namely those consuming: 1) a sodium free and normal potassium (1.3% as KCl) diet (RRM-0 Na), 2) a normal sodium and normal potassium diet (RRM-NaK), 3) a normal sodium and high potassium (2 X normal) diet (RRM-Na2K), and 4) a normal sodium and 4 times normal potassium diet (RRM-Na4K). At the end of 4 weeks of dietary treatment, direct BP was recorded, plasma level of DLS determined by bioassay and with a radioimmunoassay for digoxin (DIF) and myocardial and renal NKA activities were measured. As expected, compared to RRM-0Na rats, RRM-NaK rats developed hypertension. BP increased significantly less in RRM-Na2K, whereas BP did not increase in RRM-Na4K rats. Hypertension in RRM-NaK rats was associated with an increase in plasma DLS and DIF and decrease in renal and myocardial NKA activities. DLS was increased (DIF was not changed) and myocardial NKA also decreased in rats consuming double potassium. However, quadrupling potassium in the diet (RRM-Na4K) normalized DLS and DIF and increased myocardial and renal NKA activities, compared to RRM-0Na rats. Also compared to RRM-0Na, water consumption, urinary volume excretion, sodium, and potassium increased in the other 3 groups, more so in RRM-Na4K rats. These data show that quadrupling the potassium in the diet prevents the BP increase in RRM rats and this is associated with diuresis/natriuresis and normalization of DLS, perhaps because the diuresis/natriuresis normalizes blood volume.

[Experimental study on hypoglycemic effect of YTY granules]

OBJECT

To perform experimental pharmacodynamic evaluation of a new TCM antidiabetic drug Yitangyin (YTY).

METHODS

Experimkental streptozotocin induced rat diabetes models were subjected YTY treatment and the hypoglycemic effect was evaluated. The proved TCM Yusanxiao (YSX) was used as contrast.

RESULTS

The low, middle and high dose YTY groups exhibited significant hypoglycemic effects on the model rats. The efficiency was comparable with YSX.

CONCLUSION

The TCM YTY granule is an effective hypoglycmeic agent.

[The relationship of brainstem auditory evoked potential to cerebral blood flow volume in with vertebrobasilar transient ischemic vertigo]

This study was aimed at the relationship of brain-stem auditory evoked potential(BAEP) with cerebral blood flow(CBF) volume and vascular pathological changes in patients with vertebro-basilar transient ischemic vertigo (VBTIV). 65 patients were examined by magnetic resonance angiography(MRA), transcranial Dopplar(TCD) and BAEP; 26 controls were examined by MRA and TCD. In the patient group, MRA showed that vascular pathological changes were obvious in 50 patients, and obscure or absent in 15 patients. The CBF volume [112.3-278.9 ml/min (2s)] of control group was higher than that (48.0-262.0 ml/min) of the patients group (t = 2.43, P < 0.01) in which 15 patients had low CBF volume and 50 patients had normal CBF volume. The BAEP of 47(72.3%) patients was abnormal. Out of 15 patients with low CBF volume, 14(93.3%) had abnormal BAEP, but out of 50 patients with normal CBF volume, only 33(66%) patients had abnormal BAED (chi 2 = 4.34, P < 0.05). In the 50 patients with obscure obvious vascular pathological changes, 40(80%) patients had abnormal BAEP, but in the 15 patients with obscure or without the changes, only 7(43.3%) patients had abnormal BAEP (chi 2 = 4.86, P < 0.05). These results suggested that there might be a close relationship of BAEP with CBF volume and vascular pathological changes.

[Relationship between urinary albumin excretion and blood vessel lesion in non-insulin-dependent diabetics]

To search the relationships between urinary albumin excretion and blood vessel lesion in non-insulin-dependent diabetics, we compared the differences of blood-lipid, blood pressure, coronary heart disease and retina disease between 58 patients. The group with microalbuminuria had significantly lower concentration of apolipoprotein A, and apolipoprotein A1/apolipoprotein B100 than that of the group with normal albuminuria, but there was no significant change in concentrations of trigly cerides, total cholesterol, high density lipoprotein, and apolipoprotein B100. Coronary heart disease and retina disease were significantly increased in group with microalbuminuria. There was negative correlation with apolipoprotein A1 and value of apolipoprotein A1/apolipoprotein B100, but positive correlation with systolic blood pressure by linear regression analysis for urinary albumin excretion.

[The estrogenic activities of 2-[3-estrone-N-ethyl-piperazine-methyl]tetracycline(XW630)--a new compound with anti-osteoporosis activity]

2-[3-Estrone-N-ethyl-piperazine-methyl] tetracycline (XW630) showing anti-osteoporosis activity is a new compound with piperazine-tetracycline in the steroid structure of estrone. The affinity of XW630 with uterine estrogen receptor and its estrogenic activity were studied in this paper. The relative affinities of estrone, estradiol and XW630 with estrogen receptor (ER) of the uterine myoma tissues were found to be 0.325, 1.000 and 0.011, respectively, by the competitive assay. The estrogenic activity index of estrone, estradiol and XW630 were shown to be 9.70, 10.30 and 6.90, respectively, by the uterine weight assay using immature mice. These indexes indicate that: the estrogenic activity of XW630 is about 1/1960 that of estrone and 1/7742 that of estradiol. The vaginal smear assay of oophorectomized mice also showed that the estrogenic activity of XW630 is less than that of estrone and estradiol.

Role of digitalis-like substance in the hypertension of streptozotocin-induced diabetes and simulated weightlessness in rats

We have examined the role of plasma Na+-K+ pump inhibitor (SPI) in the hypertension of streptozotocin induced insulin dependent diabetes (IDDM) in reduced renal mass rats. The increase in blood pressure (BP) was associated with an increase in extracellular fluid volume (ECFV), and SPI and a decrease in myocardial Na+,K+ATPase (NKA) activity, suggesting that increased SPI, which inhibits cardiovascular muscle (CVM) cell NKA activity, may be involved in the mechanism of IDDM-hypertension. In a second study, using prolonged suspension resulted in a decrease in cardiac NKA activity, suggesting that cardiovascular deconditioning following space flight might in part result from insufficient SPI.

[Comparison of pharmacological effects between cultispecies Sichuan Fritillary bulb (F. wabueasis, F. mellea) and wild Sichuan Fritillary bulb (F. unibracteata)]

The ethanol extracts from the cultured Sichuan Fritillary bulb have been proved similar to those from the wild one in treating coughing in mice, expectoration in rats, asthma in guinea pigs, bronchodilation of isolated lungs in mice, and cyclic nucleotide(cAMP, cGMP) in the plasma and lungs of mice. The acute toxicity of the cultured and wild species is also similar to each other. However, in terms of asthma relieving and cAMP level increment in the lungs, the cultured species F. wabueasis is significantly superior to the wild species of Fritillary bulb.

Determination of lignocaine hydrochloride by ion-pairing flow injection with piezoelectric detection

A rapid and simple method for the determination of lignocaine hydrochloride by ion-pairing flow injection analysis was developed. It is based on the formation of an ion pair between lignocaine hydrochloride and sodium dodecyl phenylsulfonate and piezoelectric detection. The calibration curve was linear between 0.01 and 2.00 mg ml-1, with a detection limit of 8 micrograms ml-1, an RSD of 0.29% (10 replicates) and a sampling frequency of 120 h-1. The proposed method was satisfactorily applied to the determination of lignocaine hydrochloride in pharmaceutical preparations.

Effects of head down tilt on hemodynamics, fluid volumes, and plasma Na-K pump inhibitor in rats

BACKGROUND

Hindquarter suspension in rats has been used as a model of simulated weightlessness (SW) for ground based study of the effects of microgravity on the cardiovascular system (CVS).

METHODS

Using this rat model of SW we tested the hypothesis that CVS deconditioning following spaceflight results, in part, from a decrease in the circulating concentration of sodium-potassium pump inhibitor (SPI). Control rats similarly prepared were not suspended.

RESULTS

During the first hour of suspension, central venous pressure (CVP), blood pressure (BP), heart rate (HR), cardiac output (CO), plasma volume (PV), extracellular fluid volume (ECFV), urine output (UV), atrial natriuretic peptide (ANP), and the plasma level of SPI increased. Plasma renin activity (PRA) and myocardial Na+, K(+)-ATPase activity (NKA) decreased. By the end of 4 h of SW, the changes in CVP, BP, HR, ECFV, and UV persisted, but PV, plasma ANP and SPI, and myocardial NKA activity returned to control levels. By the end of 1 d of SW, ECFV and plasma SPI levels had decreased but the myocardial NKA had not increased. At day 4, CVP and BP were the same as in control sham treated rats. Plasma SPI levels were decreased at day 4 but the myocardial NKA was not different, whereas renal NKA was increased. At day 7, myocardial NKA and renal NKA were increased and vascular smooth muscle cell (VSMC) membrane potentials were hyperpolarized.

CONCLUSIONS

These data indicate that prolonged SW causes a decrease in plasma SPI level which, by hyperpolarizing VSMC, may play a role in the CVS deconditioning seen in astronauts following spaceflight.

[Effects of total saponins of semen ziziphi Spinosae on brain damages and brain biochemical parameters under cerebral ischemia of rats]

Total saponins of Semen Ziziphi Spinosae (ZS) can reduce the contents of water and MDA in ischemic rat's brain tissues, elevate the activity of SOD, CK and LDH, cut down the content of lactate and alleviate the damages of nerve cells in brain. The study shows that ZS possesses protective effects on cerebral ischemic injuries.

A study on oliguric standard in the elderly

Water deprivation test was done in 44 healthy elderly persons, 26 were male, and 18 were female. They were deprived of the intake of water for 25 hours. The results showed that the maximal renal concentration function both in the elderly males and females was 887 +/- 91 mmol/L and 888 +/- 127 mmol/L respectively. The renal excretion of waste products in 24 hours both in the elderly males and females was 815 + 170 mmol/d and 620 + 132 mmol/d respectively. On the basis of point estimation, the minimal essential urine volume per day in the elderly males and females was 926 ml/d and 708 ml/d respectively, if the daily urine volume of the elderly is less than this level, then, the metabolic products generated per day can not be excreted by the kidney, and it would result in disorders of internal environment. Therefore, the oliguric standard in elderly males and females must be less than 926 ml/d and 708 ml per day respectively.