Ropivacaine-loaded, hydroxypropyl chitin thermo-sensitive hydrogel combined with hyaluronan: an injectable, sustained-release system for providing long-lasting local anesthesia in rats.

BACKGROUND AND OBJECTIVE: Ropivacaine hydrochloride is a commonly used local anesthetic in clinics. However, local injection or continuous infusion of ropivacaine has been associated with several disadvantages. Accordingly, it is important to develop a new controlled release system for local administration of ropivacaine to achieve a prolong anesthetic effect, improve efficacy, and minimize the side effects. METHODS: We developed injectable hydroxypropyl chitin thermo-sensitive hydrogel (HPCH) combined with hyaluronan (HA), which was used to synthesize a ropivacaine (R)-loaded controlled release system. We then conducted drug release test and cytotoxicity assay in vitro. Importantly, we examined the analgesic effects and biocompatibility of this system in vivo by injecting different concentrations of R-HPCH-HA (7.5, 15, 22.5 mg/mL), ropivacaine hydrochloride (RHCL, 7.5 mg/mL), or saline (all in 0.5 mL) near the sciatic nerve in rats. RESULTS: R-HPCH-HA induced concentration-dependent thermal-sensory blockade and motor blockade in vivo. In hot plate test, R-HPCH-HA (22.5 mg/mL) induced a significant longer thermal-sensory blockade (17.7±0.7 hours), as compared with RHCL (7.5 mg/mL, 5.7±0.8 hours, n=6/group, p<0.05). It also produced a more prolonged motor blockade (6.8±0.8 hours) than RHCL (3.5±0.8 hours, p<0.05). R-HPCH-HA caused less cytotoxicity than RHCL, as indicated by the higher cell viability in vitro (n=8/group). CONCLUSION: Our findings in a sciatic nerve block model demonstrated that the injectable, ropivacaine-loaded controlled release system effectively prolonged the local analgesic effect in rats without notable side effects.

A novel anammox aggregate nourished sustainably internal heterotrophic nitrate removal pathway with endogenous carbon source.

Anaerobic ammonium oxidation (anammox) is a cost-effective nitrogen removal pathway but instinctively generated nitrate limits its application. A novel anammox aggregate reduced the production of nitrate significantly with efficient removal of ammonia and nitrite in this work. The results demonstrated that the internal heterotrophic nitrate removal (IHNAR) pathway exists stably at inner of anammox aggregates, which eliminated 42.31 ± 3.85 % nitrate generated in anammox at without consuming external carbon source. The observed volatile fatty acids (VFAs) and adequate protein, polysaccharide and humic acids in the aggregates verified that the in-situ fermentation supplied sustainably endogenous carbon sources for the IHNAR. The efficient interspecies cooperation between anammox bacteria, heterotrophic denitrifiers and fermentative bacteria was identified, as the intrinsic justification for the obtained sustainability of IHNAR pathway. The findings were expected to provide theoretical guidance for promotions and applications of the anammox process with high-efficiency total nitrogen removal capabilities.

Effects of RNAi-mediated plasma membrane calcium transporting ATPase and inositol 1,4,5-trisphosphate receptor gene silencing on the susceptibility of Mythimna separata to wilforine.

Wilforine, a compound of sesquiterpene alkaloids isolated from Tripterygium wilfordii, exhibits excellent insecticidal activity against Mythimna separata. In order to clarify the action mechanism of wilforine, the plasma membrane calcium transporting ATPase (PMCA) and inositol 1,4,5-trisphosphate receptor (IP3R) from M. separata were studied. Results showed that the open reading frame of MsIP3R and MsPMCA were 8118 bp and 3438 bp in length, as well as encoded 2706 and 1146 amino acids, respectively. Multiple sequence alignment and phylogenetic analysis revealed that the MsIP3R and MsPMCA had high homology with the IP3R and PMCA of other insects, but had low similarity with those of mammals, which means the IP3R and PMCA have potential to be the novel targets of insecticides with high selectivity between mammals and insects. Both MsIP3R and MsPMCA genes existed throughout the life cycle of M. separata, and were all predominantly expressed in somatic muscle of fifth-instar larvae and the adults. The susceptibilities of PMCA-silenced M. separata to wilforine were significantly lower than that of the normal M. separata, which illustrates that PMCA could be one of the targets of wilforine. However, the susceptibilities of IP3R-silenced M. separata to wilforine did not change significantly compared with the susceptibilities of normal M. separata, which shows that wilforine may not interact with the IP3R protein. These findings provide clues for elucidating the insecticidal mechanism of wilforine.

Epoxyeicosatrienoic acid ameliorates cerebral ischemia-reperfusion injury by inhibiting inflammatory factors and pannexin-1.

Epoxyeicosatrienoic acid (EET) has wide applications due to the unique biological effects of anti­hyperlipidemia, inhibition of platelet aggregation, anti­inflammation, anti­cancer, anti­lipid oxidation and the promotion of brain tissue development. The present study investigated whether EET ameliorates cerebral ischemia­reperfusion injury (CIRI) by inhibiting inflammatory factors and pannexin. Specific pathogen­free 7­week­old male Sprague­Dawley rats were randomly divided into three groups: Sham, CIRI and EET. Neurological deficit scores, cerebral infarct volume and cerebral edema were assessed in CIRI rats. Enzyme­linked immunosorbent assays were performed to detect tumor necrosis factor­α, interleukin­6, nuclear factor­κB and inducible nitric oxide synthase (iNOS) levels, and western blot analysis was performed also used to assess cleaved caspase­3, phospholipase A2 (PLA2), cyclooxygenase­2 and prostaglandin E2 (PGE2) protein expression levels. EET ameliorated cerebral injury and CIRI­induced cleaved caspase­3 protein expression levels in rats. EET additionally suppressed CIRI­induced inflammation reactions and iNOS protein expression in rats. Furthermore, the protein expression levels of PLA2, PGE2 and pannexin­1 in CIRI rats were inhibited by treatment with EET. These results indicated that EET reduces CIRI by inhibiting inflammation and levels of cleaved caspase­3, PLA2, PGE2 and pannexin-1.

Annual point-prevalence of healthcare-associated infection surveys in a university hospital in China, 2007-2011.

Successive point-prevalence surveys were conducted annually from 2007 to 2011 to monitor the prevalence of healthcare-associated infections (HAIs) in a university hospital in Hubei Province in China. The surveys used the case definition criteria established by the Ministry of Health of the People's Republic of China. In the 5 surveys, the overall frequency of HAIs was 3.16% (301/9533). No significant differences were identified in the point prevalence measurements of HAIs in any of the years from 2007 to 2011. Of all the cases, proportionally, the most frequent infection site was the respiratory tract (2.34%), followed by surgical sites (0.43%) and urinary tract sites (0.28%). Gram-negative aerobic bacilli were the most common organisms mentioned; the most frequently isolated organism was Pseudomonas aeruginosa, followed by Escherichia coli and Acinetobacter baumannii. Approximately one-half of the patients were receiving antibiotics at the time of the surveys. Cephalosporin, penicillin, and quinolone were most commonly used for treatment or prevention. The differences found in HAI prevalence data across the 5 surveys given in the hospital were not statistically significant. In conclusion, this successive point-prevalence survey provides information about the trend of HAI prevalence, epidemical character, and the use of antibiotics among the university hospital's in-patients. This information allows us to initiate targeted programs for infection prevention and control.

Ventilator-associated pneumonia in intensive care units in Hubei Province, China: a multicentre prospective cohort survey.

A multicentre prospective cohort study was performed in 17 intensive care units (ICUs) in tertiary care hospitals in Hubei Province, China. Ventilator-associated pneumonia (VAP) was defined according to modified criteria from the published literature. Among 4155 ventilated patients, the crude incidence and incidence rate of VAP were 20.9% and 28.9 cases per 1000 ventilator-days. Multivariate analysis using logistic regression revealed risk factors including male sex [risk ratio (RR): 1.5; P<0.001], coma (RR: 2.1; P<0.001), chronic obstructive pulmonary disease (RR: 1.4; P<0.001), infections at other sites (RR: 1.6; P=0.001), serious disease predating the onset of VAP (RR: 1.6; P<0.001) and interventions including antacid treatment (RR: 1.4; P<0.001), antimicrobial treatment (RR: 5.1; P<0.001), bronchoscopy (RR: 1.5; P=0.041) and tracheostomy (RR: 1.4; P=0.014). The most frequently isolated causative pathogens were Pseudomonas aeruginosa and Acinetobacter baumannii. Of all Staphylococcus aureus isolates, 45.7% were meticillin resistant. Rates, risk factors and causal pathogens of VAP in ICUs in Hubei differ from those reported from developed countries. These data show the need for more effective infection control interventions in Hubei, China.

Point prevalence surveys of healthcare-associated infection in 13 hospitals in Hubei Province, China, 2007-2008.

Successive point prevalence surveys were conducted in November 2007 and 2008 to monitor the prevalence of healthcare-associated infection (HCAI) in 13 grade III, 1st class hospitals in Hubei Province of China, using the case definition criteria established by the Ministry of Health in the People's Republic of China. In total, of 20 350 patients surveyed, 833 (4.09%) HCAIs were observed in 790 (3.88%) patients. There was no significant difference between the overall prevalence of HCAI in 2007 (4.14%) and 2008 (3.72%). Respiratory tract infection was the most common HCAI (63.15%), followed by surgical site infection (9.60%) and urinary tract infection (8.64%). Only 35.29% (294/833) of HCAI patients had positive microbiology results. Gram-negative bacteria were isolated most frequently and the most frequent organism was Pseudomonas aeruginosa, followed by Escherichia coli, Acinetobacter baumannii and Staphylococcus aureus. Antibiotic use was documented for 10,344 (50.83%) patients, and cephalosporins, penicillins, and quinolones were the most commonly used agents for treatment or prophylaxis.