Surface Modification of Polyurethane Membrane with Various Hydrophilic Monomers and N-Halamine: Surface Characterization and Antimicrobial Properties Evaluation.

Reducing microbial infections associated with biomedical devices or articles/furniture noted in a hospital or outpatient clinic remains a great challenge to researchers. Due to its stability and low toxicity, the N-halamine compound has been proposed as a potential antimicrobial agent. It can be incorporated into or blended with the FDA-approved biomaterials. Surface grafting or coating of N-halamine was also reported. Nevertheless, the hydrophobic nature associated with its chemical configuration may affect the microbial interactions with the chlorinated N-halamine-containing substrate. In this study, a polymerizable N-halamine compound was synthesized and grafted onto a polyurethane surface via a surface-initiated atom transfer radical polymerization (SI-ATRP) scheme. Further, using the sequential SI-ATRP reaction method, different hydrophilic monomers, namely poly (ethylene glycol) methacrylate (PEGMA), hydroxyethyl methacrylate (HEMA), and [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide (SBMA), were also grafted onto the polyurethane (PU) substrate before the N-halamine grafting reaction to change the surface properties of the N-halamine-modified substrate. It was noted that the chains containing the hydrophilic monomer and the polymerizable N-halamine compound were successfully grafted onto the PU substrate. The degree of chlorination was improved with the introduction of a hydrophilic monomer, except the HEMA. All of these hydrophilic monomer-containing N-halamine-modified PU substrates demonstrated a more than 2 log CFU reduction after microbial incubation. In contrast, the surface modified with N-halamine only exhibited significantly less antimicrobial efficacy instead. This is likely due to the synergistic effects caused by the reduced chlorine content, as well as the reduced surface interactions with the microbes.

Corrections to: Molluscicidal effectiveness of Luo-Wei, a novel plant-derived molluscicide, against Oncomelania hupensis, Biomphalaria alexandrina and Bulinus truncatus.

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Molluscicidal effectiveness of Luo-Wei, a novel plant-derived molluscicide, against Oncomelania hupensis, Biomphalaria alexandrina and Bulinus truncatus.

BACKGROUND: Control of snail intermediate hosts has been proved to be a fast and efficient approach for interrupting the transmission of schistosomiasis. Some plant extracts have shown obvious molluscicidal activity, and a new compound Luo-Wei, also named tea-seed distilled saponin (TDS), was developed based on the saponins extracted from Camellia oleifera seeds. We aimed to test the molluscicidal activity of 4% TDS against the intermediate host snails in China and Egypt, and evaluate its environmental safety to non-target organisms. METHODS: In the laboratory, Oncomelania hupensis, Biomphalaria alexandrina and Bulinus truncatus were exposed to 4% TDS, and the median lethal concentration (LC50) was estimated at 24, 48 and 72 h. In the field, snail mortalities were assessed 1, 2, 3 and 7 d post-immersion with 2.5 g/m3 4% TDS and 1, 3, 7 and 15 d post-spraying with 5 g/m2 4% TDS. In addition, the acute toxicity of 4% TDS to Japanese quail (Coturnix japonica), zebrafish (Brachydanio rerio) and freshwater shrimp (Macrobrachium nipponense) was assessed by estimations of LC50 or median lethal dose (LD50). RESULTS: In the laboratory, the LC50 values of 4% TDS for O. hupensis were 0.701, 0.371 and 0.33 mg/L at 24, 48 and 72 h, respectively, and 4% TDS showed a 1.975 mg/L [corrected] 24 h LC50 against B. alexandrina, and a 1.396 mg/L 24 h LC50 against B. truncatus. Across all study regions, the pooled mortalities of O. hupensis were 72, 86, 94 and 98% at 1, 2, 3 and 7 d, following field immersion of 4% TDS at a dose of 2.5 g/m3, and were 69, 77, 85 and 88% at 1, 3, 7 and 15 d, following field spraying at 5 g/m2, respectively. 4% TDS had moderate toxicity to Japanese quail (7 d LD50 > 60 mg/kg) and to shrimp (96 h LC50 = 6.28 mg/L; 95% CI: 3.53-11.2 mg/L), whereas its toxicity to zebrafish was high (96 h LC50 = 0.15 mg/L; 95% CI: 0.14-0.17 mg/L). CONCLUSIONS: 4% TDS is active against O. hupensis, B. alexandrina and B. truncatus under laboratory and field conditions, and it may be a candidate molluscicide of plant origin.

[Research on competency building standards of institutions of schistosomiasis prevention and control in Hubei Province I Investigation of institution management].

OBJECTIVE: To investigate the current situation of management of institutions of schistosomiasis prevention and control in Hubei Province, so as to explore the probable competency building standards for these institutions at the county and township levels. METHODS: By using a combination of quantitative and qualitative methods, the institutions of schistosomiasis prevention and control at county and township levels were investigated for the institutional setup, staffing and fulfillment functions since the reform of 2004. RESULTS: Among 63 schistosomiasis endemic counties (cities, districts) of Hubei Province, there were 26 independent schistosomiasis control institutions (41.27%), there were 24 institutions which were incorporated into CDC (38.10%), and there were no institutions in 13 counties (20.63%). Among 518 endemic towns, there were 299 institutions (57.72%). The total staffing size were 1 932, but there were 1 586 (82.09%) people actually working in the post, and therefore there were 346 (17.91%) empty positions. The average rates of carrying out the six functions were 91.48%-71.19%, but only 19.23% of the institutions participated in the comprehensive schistosomiasis control management project and its effect assessment. CONCLUSION: According to the management model for schistosomiasis control institutions under the current institutional mechanisms, we need a rigorous industry standard to constrain, guide and standardize the management and capacity-building of the institutions in different historical periods.

[Molluscicidal effect comparison between TDS and MNSC in field].

OBJECTIVE: To compare the molluscicidal effects between "Luo-wei" (TDS), a plant molluscicide in 4 percent, and metaldehyde and niclosamide (MNSC) in the field. METHODS: A natural ecological environment with Oncomelania hupensis was selected as the test area, the test concentrations of TDS and MNSC were 2.5 g/m3 and 2 ml/m3 respectively by the immersion method; the test doses of TDS and MNSC were 3 g/m2 and 2 ml/m2 respectively by the spray method; the doses of WPN in a control group were 2 g/m3 and 2 g/m2 respectively by the two methods above-mentioned. The molluscicidal effects between TDS and MNSC were compared by using the synchronous design method and parallel comparative method. RESULTS: In the TDS group, the death rate of snails was 90.70% by immersion for 24 hours, reached to 81.40% after spraying for 7 days, and there were no significant differences among the observation time points in molluscicidal effects (P > 0.05). One day after the spraying, the death rate of snails was less in the TDS group compared with that in the MSCN group (P < 0.01), but the death rates of snails were similar in both groups 3 days after the spraying (P > 0.05). In the MSCN group, the death rate of snails was 99.17% by immersion for 24 hours, reached to 66.07% by spraying for 1 day. In the WPS group, the death rate of snails was 97.15% by immersion for 24 hours, reached to 71.43% after spraying for 1 day, and there were no significant differences (both P > 0.05). CONCLUSION: TDS has a good molluscicidal activity and stable efficacy, and the molluscicidal effect of TDS is similar to that of MSCN in the filed, but the molluscicidal sensitivity of TDS is lower than that of MSCN.

[Research on competency building standards of institutions of schistosomiasis prevention and control in Hubei Province. II. Investigation of human resources].

OBJECTIVE: To understand the human resources of the grassroots institutions of schistosomiasis control and prevention, so as to provide the evidence for formulating the standards of institutional capacity-building. METHODS: By using the combination of quantitative and qualitative methods, the hierarchy of schistosomiasis control institution workers, structural features of workers, and benefits of workers were investigated and the results were analyzed statistically after the 2004 reform. RESULTS: The constituent ratios of personnel ≤ 30 years old, 30 to 45 years old, and ≥ 45 years old were 6.8%, 64.0% and 29.2% respectively, with an average age of 43.1 years. For education levels, 61.35% of the personnel had secondary or high school levels. At the city level, the structural proportion of the senior professional; medium professional and primary professional titles was 1.4 : 5.6 : 3.0, and at the county level, the proportion was 0.5 : 6.1 : 3.4. There was 14 200 yuan per capita at the township schistosomiasis control institutions. CONCLUSION: The technology of the personnel in schistosomiasis institutions of Hubei Province is weak, the average age of personnel is old, and the salary is low.

[Molluscicidal effect of plastic film mulch covering method].

OBJECTIVE: To evaluate the molluscicidal effect of the plastic film mulch covering method. METHODS: In the barren land with a lot of Oncomelania hupensis snails, 3 experimental groups were set up, in which respectively using 3 different methods: a simple plastic film mulch covering method, film assisted with ammonium bicarbonate, and film assisted with amine molluscicide. In the canals, two experimental groups were set up, in which respectively using 2 different methods: simple plastic film mulch covering method and film assisted with ammonium bicarbonate. In above-mentioned areas, obstacles were cleared artificially. In each experiment group, 4 observation spots were set up, and 100 living snails were pot in each spot, and then, the plastic film mulch was evenly covered. The status of the snails was observed 3, 7, 15 and 30 days after the intervention. RESULTS: In the barren land, the snail death rates of the simple plastic film group were 20.77% and 96.92% 15 days and 30 days after the intervention, respectively. The snail death rate of the film assisted with amine molluscicide group was 80.46% 3 days after the intervention. In all the experiment groups, the snail death rates were from 96.92 to 100% 30 days after the intervention. CONCLUSION: The plastic film mulch covering method has a great molluscicide effect in the hill subtype and water network type of schistosomiasis epidemic areas.

[Effects of preoperative oral carbohydrate on postoperative insulin resistance in radical gastrectomy patients].

OBJECTIVE: To investigate the effects and mechanism of postoperative insulin resistance in gastrectomy patients with preoperative oral carbohydrate. METHODS: From April to October 2011, 60 consecutive gastric cancer patients met inclusion criteria were divided into oral carbohydrate group and placebo group by randomized double-blind principles. Resting energy expenditure (REE), fasting blood glucose, insulin and triglyceride level were detected in 4 hours preoperatively. The 500 ml carbohydrate or placebo were administrated orally 2-3 hours before anaesthesia. Two group patients underwent radical distal subtotal gastrectomy under epidural compounded intravenous anesthesia. After laparotomy and before the abdomen was closed, a piece of rectus abdominis was taken and fixed in 3% glutaraldehyde. REE, fasting blood glucose, insulin and triglyceride level were detected immediately after surgery. The changes of insulin resistance index, blood triglycerides level, REE and respiratory quotient were compared pre- and post-operatively. The changes of rectus abdominis mitochondrial ultrastructure were observed by transmission electron microscopy respectively. RESULTS: There were 48 patients (34 males and 14 females) completed the trial. The 24 and 24 patients in oral placebo and carbohydrate groups respectively. In oral placebo group, post-operative insulin resistance index, REE, respiratory quotient, serum triglyceride level and the rectus abdominis mitochondrial damage index were 12.68 ± 3.13, (1458 ± 169) kcal/d, 0.73 ± 0.42, (0.53 ± 0.24) g/L and 1.14 ± 0.33, respectively. And the above items were 5.67 ± 1.40, (1341 ± 110) kcal/d, 0.79 ± 0.22, (1.04 ± 0.97) g/L and 0.92 ± 0.19 in oral carbohydrate groups respectively. All difference was statistically significant (t = 6.646, 2.851, 6.546, 2.542 and 2.730, all P < 0.05). Oral placebo group showed a markedly swollen mitochondria, steep membrane was not clear, mitochondria appeared vacuolated changes. CONCLUSIONS: Preoperative oral carbohydrate could reduce the insulin resistance and REE, improve the material metabolism status in radical gastrectomy patients. The possible mechanisms should be related to promotion of insulin release and protection of mitochondrial function.

Effect of intensive vs conventional insulin therapy on perioperative nutritional substrates metabolism in patients undergoing gastrectomy.

AIM: To investigate the effect of intensive vs conventional insulin therapy on perioperative nutritional substrates metabolism in patients undergoing radical distal gastrectomy. METHODS: Within 24 h of intensive care unit management, patients with gastric cancer were enrolled after written informed consent and randomized to the intensive insulin therapy (IIT) group to keep glucose levels from 4.4 to 6.1 mmol/L or the conventional insulin therapy (CIT) group to keep levels less than 10 mmol/L. Resting energy expenditure (REE), respiratory quotient (RQ), resting energy expenditure per kilogram (REE/kg), and the lipid oxidation rate were monitored by the indirect calorimeter of calcium citrate malate nutrition metabolism investigation system. The changes in body composition were analyzed by multi-frequency bioimpedance analysis. Blood fasting glucose and insulin concentration were measured for assessment of Homeostasis model assessment of insulin resistance. RESULTS: Sixty patients were enrolled. Compared with preoperative baseline, postoperative REE increased by over 22.15% and 11.07%; REE/kg rose up to 27.22 ± 1.33 kcal/kg and 24.72 ± 1.43 kcal/kg; RQ decreased to 0.759 ± 0.034 and 0.791 ± 0.037; the lipid oxidation ratio was up to 78.25% ± 17.74% and 67.13% ± 12.76% supported by parenteral nutrition solutions from 37.56% ± 11.64% at the baseline; the level of Ln-HOMA-IR went up dramatically (P < 0.05, respectively) on postoperative days 1 and 3 in the IIT group. Meanwhile the concentration of total protein, albumin and triglyceride declined significantly on postoperative days 1 and 3 compared with pre-operative levels (P < 0.05, respectively). Compared with the CIT group, IIT reduced the REE/kg level (27.22 ± 1.33 kcal/kg vs 29.97 ± 1.47 kcal/kg, P = 0.008; 24.72 ± 1.43 kcal/kg vs 25.66 ± 1.63 kcal/kg, P = 0.013); and decreased the Ln-HOMA-IR score (P = 0.019, 0.028) on postoperative days 1 and 3; IIT decreased the level of CRP on postoperative days 1 and 3 (P = 0.017, 0.006); the total protein and albumin concentrations in the IIT group were greater than those in the CIT group (P = 0.023, 0.009). Postoperative values of internal cell fluid (ICF), fat mass, protein mass (PM), muscle mass, free fat mass and body weight decreased obviously on postoperative 7th day compared with the preoperative baseline in the CIT group (P < 0.05, respectively). IIT reduced markedly consumption of fat mass, PM and ICF compared with CIT (P = 0.009 to 0.026). CONCLUSION: There were some benefits of IIT in decreasing the perioperative insulin resistance state, reducing energy expenditure and consumption of proteins and lipids tissue in patients undergoing gastrectomy.

[Perioperative blood glucose control].

Hyperglycemia can result in severe adverse effects on the body. The mortality and morbidity of surgery are increased significantly in diabetic patients. The surgical stress-related hyperglycemia and insulin resistance can also produce the same adverse consequences. The metabolic state of the surgical patients, anesthesia method, glucose infusion, stress-induced neuroendocrine responses and insulin resistance can affect the perioperative blood glucose levels, resulting in poor clinical outcomes. The relationship between tight glycemic control and reducing post-operative mortality and morbidity is not clear. It's necessary to control blood sugar level during the perioperative period but the ideal state of glycemic control still needs a mult-center clinical trial evidence. It is generally believed that perioperative blood glucose level should be controlled below 10 mmol/L. The efficacy and safety of tight glycemic control needs further study.

[Effect of different perioperative treatments on gut flora in SD rats].

OBJECTIVE: To study the effects of different perioperative treatments on the number and proportion of gut flora in SD rats. METHODS: Forty-eight SD rats were randomized into 8 groups including the control group, antibiotics group, bowel preparation group, fasting group, antibiotic-bowel preparation group, antibiotics-bowel preparation-fasting group, bowel preparation-surgery-antibiotics-early postoperative feeding group (early feeding group), and bowel preparation-surgery-antibiotics-postoperative fasting group. The rats were sacrificed and stool specimens were collected from the cecum. Stools were diluted and transferred to selective medium. Bacteria counts were calculated after 48 hours of culture under constant temperature. The changes in gut flora between the different groups were compared in terms of E.coli, Bacteroides, Bifidobacterium, and Enterococcus. RESULTS: Compared with the control group, the total bacteria, Bacteroid, Enterococcus, Bifidobacterium were all significantly decreased(P<0.05), while the E.coli count and the bacillus/coccus ratio were significantly elevated(P<0.05). In the bowel preparation group, the total bacteria count, Bacteroid, Enterococcus, Bifidobacterium were all significantly decreased(P<0.05), while the E.coli count remained stable(P>0.05) and the bacillus/coccus ratio was significantly elevated(P<0.05). In the fasting group, the total bacteria count, Bacteroid, Enterococcus, Bifidobacterium were all significantly decreased(P<0.05), while the E.coli count remained stable(P>0.05) and the bacillus/coccus ratio was significantly elevated(P<0.05). Early postoperative feeding increased E.coli, Enterococcus, and total bacteria count(P<0.05), and lowered bacillus/coccus ratio(P<0.05) as compared to the fasting group. CONCLUSIONS: Antibiotics, bowel preparation, and fasting have influence on the gut flora of SD rats in count and bacillus/coccus ratio, leading to dysbiosis. Early postoperative feeding may improve dysbiosis.

[Effect of intensive insulin therapy on resting energy expenditure in postoperative patients underwent radical distal gastrectomy].

OBJECTIVE: To investigate the effect of intensive insulin therapy on resting energy expenditure in postoperative patients underwent radical distal gastrectomy. METHODS: Sixty-four patients with gastric neoplasms in the middle or lower part of stomach from January to October 2010 were enrolled and underwent radical distal gastrectomy, then were randomized to intensive insulin therapy (IIT) group to keep glucose levels from 4.4 to 6.1 mmol/L or conventional insulin therapy (CIT) group to keep levels from 4.4 to 10.0 mmol/L. Resting energy expenditure (REE), respiratory quotient (RQ), resting energy expenditure per kilogram (REE/kg) and lipid oxidation ratio (LOR) were monitored by indirect energy metabolic system on preoperative and postoperative 1(st), 3(rd) and 7(th) day. Fasting blood glucose and insulin concentration were measured for HOMA-IR assessment. RESULTS: Compared with preoperative baseline, postoperative REE, REE/kg, LOR, Ln-HOMA-IR increased dramatically (P < 0.05, respectively). RQ decreased markedly (P < 0.05). Compared with group CIT, IIT reduced the REE/kg level [(27.2 ± 1.3) kcal/kg vs. (30.0 ± 1.5) kcal/kg, P = 0.008; (24.7 ± 1.4) vs. (25.7 ± 1.6) kcal/kg, P = 0.013]; and decreased the Ln-HOMA-IR score (P = 0.019 and 0.028) on postoperative 1(st) and 3(rd) day; IIT could decrease obviously the level of C-reaction protein level on postoperative 1(st) and 3(rd) day (P = 0.017, 0.006). The total protein and albumin concentration in IIT group were more than its levels in group CIT (P = 0.023, 0.009). CONCLUSION: There are some benefits of IIT in reducing mean energy expenditure and the consumption of proteins, decreasing postoperative insulin resistance level in this small population underwent radical distal gastrectomy.