[Clinical characteristics of hospitalized children with respiratory syncytial virus infection and risk prediction of severe illness during the post-COVID-19 era in Kunming].

Objective: To compare the epidemiological and clinical characteristics of hospitalized children with respiratory syncytial virus (RSV) infection in Kunming among the pre-and post-COVID-19 era, and to establish a prediction model for severe RSV infection in children during the post-COVID-19 period. Methods: This was a retrospective study. Clinical and laboratory data were collected from 959 children hospitalized with RSV infection in the Department of Pulmonary and Critical Care Medicine at Kunming Children's Hospital during January to December 2019 and January to December 2023. Patients admitted in 2019 were defined as the pre-COVID-19 group, while those admitted in 2023 were classified as the post-COVID-19 group. Epidemiological and clinical characteristics were compared between the two groups. Subsequently, comparison of the clinical severity among the two groups was performed based on propensity score matching (PSM). Furthermore, the subjects in the post-COVID-19 group were divided into severe and non-severe groups based on clinical severity. Chi-square test and Mann-Whitney U test were used for pairwise comparison between groups, and multivariate Logistic regression was applied for the identification of independent risk factors and construction of the prediction model. The receiver operating characteristic (ROC) curve and calibration curve were employed to evaluate the predictive performance of this model. Results: Among the 959 children hospitalized with RSV infection, there were 555 males and 404 females, with an onset age of 15.4 (7.3, 28.5) months. Of which, there were 331 cases in the pre-COVID-19 group and 628 cases in the post-COVID-19 group. The peak period of RSV hospitalization in the post-COVID-19 group were from May to October 2023, and the monthly number of inpatients for each of these months were as follows: 72 cases (11.5%), 98 cases (15.6%), 128 cases (20.4%), 101 cases (16.1%), 65 cases (10.4%), and 61 cases (9.7%), respectively. After PSM for general data, 267 cases were matched in each group. The proportion of wheezing in the post-COVID-19 group was lower than that in the pre-COVID-19 group (109 cases (40.8%) vs. 161 cases (60.3%), χ2=20.26, P<0.001), while the incidences of fever, tachypnea, seizures, severe case, neutrophil-to-lymphocyte ratio (NLR), C-reactive protein and interleukin-6 levels were all higher than those in the pre-COVID-19 group (146 cases (54.7%) vs. 119 cases (44.6%), 117 cases (43.8%) vs. 89 cases (33.3%), 37 cases (13.9%) vs. 14 cases (5.2%), 69 cases (25.8%) vs. 45 cases (16.9%), 3.6 (1.9, 6.4) vs. 2.3 (1.8, 4.6), 9.9 (7.1, 15.2) vs. 7.8 (4.5, 13.9) mg/L, 20.5 (15.7, 30.4) vs. 17.2 (11.0, 26.9) ng/L, χ2=5.46, 6.36, 11.47, 6.42, Z=4.13, 3.06, 2.96, all P<0.05). There were 252 cases and 107 cases with co-infection in the post-and pre-COVID-19 groups, respectively. The proportion of triple and quadruple infection in the post-COVID-19 group was higher than that in the pre-COVID-19 group (59 cases (23.4%) vs. 13 cases (12.1%), 30 cases (11.9%) vs. 5 cases (4.7%), χ2=5.94, 4.46, both P<0.05). Among the 252 cases with co-infection in post-COVID-19 group, the most prevalent pathogens involving in co-infections, in order, were Mycoplasma pneumoniae 56 cases (22.2%), Influenza A virus 53 cases (21.0%), Rhinovirus 48 cases (19.0%), Parainfluenza virus 35 cases (13.9%), and Adenovirus 28 cases (11.1%).The result of multivariate Logistic regression showed that age (OR=0.70, 95%CI 0.62-0.78, P<0.001), underlying diseases (OR=10.03, 95%CI 4.10-24.55, P<0.001), premature birth (OR=6.78, 95%CI 3.53-13.04, P<0.001), NLR (OR=1.85, 95%CI 1.09-3.15, P=0.023), and co-infection (OR=1.28, 95%CI 1.18-1.38, P<0.001) were independently associated with the development of severe RSV infection in the post-COVID-19 group. The ROC curve of the prediction model integrating the above five factors indicated an area under the curve of 0.85 (95%CI 0.80-0.89, P<0.001), with an optimal cutoff of 0.21, a sensitivity of 0.83 and a specificity of 0.80. The calibration curve showed that the predicted probability in this model did not differ significantly from the actual probability (P=0.319). Conclusions: In the post-COVID-19 era in Kunming, the peak in pediatric hospitalizations for RSV infection was from May to October, with declined incidence of wheezing and increased incidence of fever, tachypnea, seizures, severe cases, and rates of triple and quadruple co-infections. Age, underlying diseases, premature birth, NLR, and co-infection were identified as independent risk factors for severe RSV infection in the post-COVID-19 period. In this study, a risk prediction model for severe pediatric RSV infection was established, which had a good predictive performance.

[Application of failure mode and effect analysis in reducing the risk of nosocomial infection].

Objective: To explore the effect of failure mode and effect analysis (FMEA) in the management of nosocomial infection, and provide reference for the effective prevention and control of nosocomial infection. Methods: Using FMEA to identify, analyze, evaluate and screen out the high-risk events of nosocomial infection in January 2020, from which two hospital level priority improvement projects of hand hygiene compliance and blood-borne occupational exposure were determined. After risk control and intervention measures, the effects before and after improvement were compared. Results: Except for the lack of incentive mechanism and insufficient communication between medical and nursing teams, the differences in hand hygiene compliance and blood-borne occupational exposure risk priority coefficients before and after the implementation of FMEA were statistically significant (P<0.05) . After the implementation of FMEA, the hand hygiene compliance was 74.92% (79375/105953) , which was significantly higher than 68.40% (58361/85328) before the implementation of FMEA, and the difference was statistically significant (χ(2)=996.55, P<0.01) . The incidence of blood-borne occupational exposure after the implementation of FMEA was 3.85% (80/2080) , which was lower than the 6.16% (123/1998) before the implementation of FMEA, and the difference was statistically significant (χ(2)=11.49, P<0.01) . Conclusion: FMEA has a good effect in nosocomial infection management. It can identify and evaluate the risk of nosocomial infection prospectively, so as to control the risk effectively.

[Study on analgesic effect and mechanism of cinobufagin on rats with bone cancer pain].

Objective: To evaluate the analgesic effects of cinobufagin (CBG) on cancer-induced bone pain in rat and study the role of the muscarinic receptor M4 subtype (M4 mAChR) in its involvement. Methods: A total of 100 Female Sprague-Dawley rats were randomly divided into 5 groups (n=20): Sham group (group S), Cancer group (group A), Normal saline + CBG vehicle solution group (group ANS), Normal saline + 1 mg/kg CBG group (group ANC) and Tropicamide + 1 mg/kg CBG group (group ATC). Rats in group S were injected 10 µl Hank's solution into the left tibia medullar cavity, while rats in group A, ANS, ANC, and ATC were injected Walker 256 mammary cancer cells (10 µl, 2×10(7) cells/ml) into the same place. On day 9 post-inoculation rats in group ANS, ANC, and ATC were respectively received Saline (0.9%, 15 µl, i.t.), Saline (0.9%, 15 µl, i.t.)and 10 nmol of M4 mAChR blocker Tropicamide. After 10 min, ANS group, ANC group and ATC group were intraperitoneally injected with CBG vehicle solution, 1 mg/kg CBG and 1 mg/kg CBG. Model rats in each group were tested three times average as its basis pain threshold before injection cancer cells (T(0)). Mechanical withdrawal thresholds were measured on left hind paws, before 20 min (T(1)) and after 10 min (T(2)), 30 min (T(3)), 60 min (T(4)), 90 min (T(5)) and 120 min (T(6)) intrathecal injection. Left L4-L6 spinal dorsal horn and DRG were removed for determination of the expression of CaM-dependent kinaseⅡa (CaMKⅡa) and pCaMKⅡa by Western Blot after 60 min drug delivery. Results: At each time point from T(1) to T(6), the mechanical pain thresholds of group S were (8.69±0.45), (8.63±0.44), (8.65±0.39), (8.84±0.23), (8.80±0.14), (8.75±0.14) g, respectively, and the mechanical pain thresholds of group A were (6.37±0.30), (6.42±0.13), (6.29±0.17), (6.25±0.22), (6.34±0.33), (6.36±0.34) g, the difference was statistically significant (t=-16.41, -23.47, -30.25, -17.35, -19.52, -22.56, all P<0.01). At each time point from T(3) to T(5), the mechanical pain thresholds of the ANS group were (6.42±0.32), (6.39±0.34), (6.26±0.32) g, respectively, and the mechanical pain thresholds of the ANC group were (7.29±0.34), (7.81±0.15), (7.54±0.19) g, the difference was statistically significant (t=13.52, 14.22, 17.33, all P<0.01). At each time point from T(3) to T(5), compared with the ANC group, the mechanical pain threshold of the ATC group decreased (6.55±0.23), (6.84±0.46), (6.80±0.43) g, and the difference was statistically significant (t=-12.69, -11.26, -10.33, all P<0.01). At the time of T(4), the expressions of pCaMKⅡa in the spinal dorsal horn of each group were (0.67±0.05), (1.64±0.12), (1.57±0.14), (0.78±0.09), (1.39±0.11), respectively, and the expressions of pCaMKⅡa in DRG of each group were (1.65±0.39), (3.59±0.17), (3.43±0.32), (2.17±0.34), (2.95±0.23). The differences were statistically significant (F=179.89, 198.76, both P<0.01). Compared with the S group, the expression of pCaMⅡa was up-regulated in group A. Compared with ANS group, the expression of pCaMKⅡ a was down-regulated in ANC group. Compared with ANC group, the expression of pCaMK Ⅱ a was up-regulated in ATC group. The expression of CaMKⅡa in spinal dorsal horn and DRG was not statistically significant (F=1.25, 2.79, both P>0.05). Conclusions: These results demonstrated that M4mAChR participated in mediating the alleviation of hyperalgesia by cinobufagin in rats with bone cancer pain, and its mechanism may be related to pCaMKⅡa/CaMKⅡa signaling pathway.

Dynamics and regulation of glycolysis-tricarboxylic acid metabolism in the midgut of Spodoptera litura during metamorphosis.

Significant changes usually take place in the internal metabolism of insects during metamorphosis. The glycolysis-tricarboxylic acid (glycolysis-TCA) pathway is important for energy metabolism. To elucidate its dynamics, the mRNA levels of genes involved in this pathway were examined in the midgut of Spodoptera litura during metamorphosis, and the pyruvate content was quantified. The expression patterns of these genes in response to starvation were examined, and the interaction between protein phosphatase 1 (PP1) and phosphofructokinase (PFK) was studied. The results revealed that the expression or activities of most glycolytic enzymes was down-regulated in prepupae and then recovered in some degree in pupae, and all TCA-related genes were remarkably suppressed in both the prepupae and pupae. Pyruvate was enriched in the pupal midgut. Taken together, these results suggest that insects decrease both glycolysis and TCA in prepupae to save energy and then up-regulate glycolysis but down-regulate TCA in pupae to increase the supply of intermediates for construction of new organs. The expression of all these genes were down-regulated by starvation, indicating that non-feeding during metamorphosis may be a regulator of glycolysis-TCA pathway in the midgut. Importantly, interaction between PP1 and PFK was identified and is suggested to be involved in the regulation of glycolysis.

Transcription factor CAAT/enhancer-binding protein is involved in regulation of expression of sterol carrier protein x in Spodoptera litura.

The Spodoptera litura sterol carrier protein x (SlSCPx) gene is expressed in various tissues throughout the life cycle and plays important role in sterol absorption and transport. In this study, the effects of insect hormones (20-hydroexcdysone and juvenile hormone) and lipids (arachidonic acid, cholesterol) on the expression of SlSCPx was analysed by reverse-transcriptase PCR. The results showed that none of these substances significantly induced the expression of SlSCPx in Spodoptera litura-221 (Spli-221) cells. To identify the transcription factors responsible for regulation of SlSCPx expression, a 3311-bp promoter sequence of the gene was cloned. Transcriptional activity of the promoter was studied using an in vivo promoter/reporter system and a 29-bp sequence between -1000 and -1029 nucleotides (nt) upstream of this gene was found to be responsible for the up-regulation of the gene. Over-expression of CAAT/enhancer-binding protein (C/EBP) in Spli-221 cells increased the promoter activity 5.57-fold. An electrophoretic mobility shift assay showed that two nuclear proteins bound to this sequence. Recombinant C/EBP specifically bound with a putative cis-regulatory element (CRE). Mutation of the C/EBP CRE abolished the binding of the C/EBP with the CRE. These results suggest that the transcription factor C/EBP may regulate the expression of SlSCPx by binding to the CRE in the promoter of this gene.

In vitro degradation of porous PLLA/pearl powder composite scaffolds.

The in vitro degradation behavior of poly-L-lactide (PLLA), PLLA/aragonite pearl powder and PLLA/vaterite pearl powder scaffolds was investigated. The scaffolds were soaked in phosphate buffer solution (PBS) up to 200 days. Scanning electron microscopy (SEM), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) were used to observe any degradation of the scaffolds. Degradation behaviors such as changes in pH, porosity, bulk density, water absorption, weight loss and mechanical properties were discussed. The results show that a gradual increase of the pH in composite scaffolds can decrease the rate of hydrolysis of PLLA. PLLA/vaterite and PLLA/aragonite scaffolds have a similar degradation behavior but a slower rate of degradation than PLLA.

The treatment of severe and multiple injuries in intensive care unit: report of 80 cases.

OBJECTIVE: To summarize our case load in managing severe and multiple injuries (SMI) in the Intensive Care Unit (ICU). PATIENTS AND METHODS: The clinical data of 80 SMI patients treated in our ICU from January 2009 to June 2013 were analyzed. RESULTS: Results of these 80 SMI patients, 60 (75%) were salvaged and 15 (18.75%) died. The causes of death included severe head injury (n=7), severe chest injury (n=3), destruction of injured abdominal organs (n=2), and multiple organ dysfunction syndrome (n=3). Five patients (7.50%) gave up treatment and were discharged upon their own requests. Early application of continuous renal replacement therapy (CRRT) and enteral nutrition (EN) improved outcomes. CONCLUSIONS: The key interventions during the ICU treatment of SMI include: adequate analgesia and appropriate sedation; timely management of hypoxemia; reasonable fluid resuscitation and CRRT.

Hsp70 and small Hsps are the major heat shock protein members involved in midgut metamorphosis in the common cutworm, Spodoptera litura.

Heat shock proteins (Hsps) are important chaperones, which are involved in various signal pathways and regulate lots of physiological processes. Early research suggested that some Hsps are involved in insect development. However, few studies have been carried out to explore the roles of Hsps, especially in larval-pupal metamorphosis. In the present study, 49 Hsp unigenes were identified in the Spodoptera litura transcriptome and their mRNA expression profiles during midgut metamorphosis were examined using a tag-based digital gene expression system. The genes with the most different levels of expression were then cloned and their expression patterns in midguts from sixth instar larvae to pupae were analysed using real time quantitative PCR. The responses of these genes to juvenile hormone (JH) and 20-hydroxyecdysone (20E) were also studied. The results showed that the mRNA levels of 22 Hsp unigenes changed significantly during midgut metamorphosis. Amongst these 22 unigenes, hsp70, hsp20.4 and hsp20.8 were the most up-regulated members, and hsp15.9, hsp19.3 and hsp22.0 were the most down-regulated ones. Further studies showed that hsp70, hsp20.4 and hsp20.8 were remarkably up-regulated by JH. In addition, 20E slightly increased the mRNA levels of both hsp20.4 and hsp20.8. However, hsp15.9, hsp19.3 and hsp22.0 did not respond to either JH or 20E. These results indicate that Hsp70 and small Hsps (sHsps) are probably the major players in midgut metamorphosis in S. litura. The current findings provide valuable insights into the roles of the Hsp superfamily in insect metamorphosis.

Controls on body size during the Late Permian mass extinction event.

This study examines the morphological responses of Late Permian brachiopods to environmental changes. Quantitative analysis of body size data from Permian-Triassic brachiopods has demonstrated significant, directional changes in body size before, during and after the Late Permian mass extinction event. Brachiopod size significantly reduced before and during the extinction interval, increased for a short time in more extinction-resistant taxa in the latter stages of extinction and then dramatically reduced again across the Permian/Triassic boundary. Relative abundances of trace elements and acritarchs demonstrate that the body size reductions which happened before, during and after extinction were driven by primary productivity collapse, whereas declining oxygen levels had less effect. An episode of size increase in two of the more extinction-resistant brachiopod species is unrelated to environmental change and possibly was the result of reduced interspecific competition for resources following the extinction of competitors. Based on the results of this study, predictions can be made for the possible responses of modern benthos to present-day environmental changes.

Cloning, expression and characterization of four serpin-1 cDNA variants from the spruce budworm, Choristoneura fumiferana.

Four cDNAs (Cfserpin-1a, Cfserpin-1b, Cfserpin-1c and Cfserpin-1d) of the Choristoneura fumiferana serpin-1 gene were cloned from an epidermis cDNA library. Analysis of the deduced amino acid sequences indicated that the cloned cDNAs encode four different proteins displaying identical N- but distinct C-termini, the latter region containing the inhibitory loop. The entire CfSerpin-1 gene is transcribed while the variants are generated. Antibodies generated against the purified recombinant serpins cross-reacted with the other three. Each of the four Cfserpin-1 cDNA variants was transcribed throughout larval development, from the 4th to the 6th instar, but transcript levels during the intermolt phases were generally higher than during the molting phase. The epidermis and fat body had higher levels of Cfserpin-1 transcripts than the midgut. Cfserpin-1 proteins, detected with the Cfserpin-1a antibody, were found in the epidermis, midgut, fat body, plasma and molting fluid of 6th instar larvae and pre-pupae. Prepupal and pupal insects had higher levels of the proteins than the 6th instar feeding larvae, despite a drop in transcript levels. Cfserpin-1a could bind with the serine proteinase elastase and form a complex in vitro. We hypothesize that the cloned serpins could be involved in the regulation of cuticle degradation during the insect molting cycle.

Cloning, expression, and localization of a molt-related beta-N-acetylglucosaminidase in the spruce budworm, Choristoneura fumiferana.

A beta-N-acetylglucosaminidase cDNA (CfGlcNAcase) was cloned from the spruce budworm, Choristoneura fumiferana. Western blotting analysis of developmental CfGlcNAcase expression revealed high levels of expression of the gene on the last day of the 5th instar larvae and the first day in the 6th instar larvae, followed by a decrease to background levels during the intermolt of the 6th instar. CfGlcNAcase was detected again from the last day of the 6th instar to day 2 of pupal stage. CfGlcNAcase expression was induced by tebufenozide at 24 h post treatment and remained at high levels until 72 h. Immunohistochemical localization analysis of CfGlcNAcase indicated that CfGlcNAcase was present in the molting fluid, epidermis, trachea, and hemolymph in prepupae during the transformation from larva to pupa. CfGlcNAcase cDNA was expressed into a recombinant protein in bacterial and baculovirus systems and the protein expressed in the baculovirus system had a higher chitinolytic activity than in the bacterial system and appeared to be secreted.

Two lepidopteran cell lines stably transformed by the abc transporter gene pdr5 show tolerance to diacetoxyscirpenol.

The pleiotropic drug resistance 5 gene (pdr5) encodes a multidrug membrane transporter and plays a very important role in the efflux of a broad range of chemicals in yeast cells. To study the possible function of pdr5 in insect cells, two stably pdr5-transformed lepidopteran insect cell lines, Sf21 and CF-203, were developed. Transcripts of pdr5 were detected in these two lines using Northern blotting and RT-PCR analysis. When cells were treated with the protein synthesis inhibitor diacetoxyscirpenol, the transformed Sf21 and CF-203 cell lines showed increased tolerance to this chemical. However, unlike in yeast cells, ecdysone agonist RH5992 could not be excluded by PDR5, probably because of low expression levels or imperfect incorporation of the recombinant protein in these transformed cell lines.

Molecular cloning and characterization of a putative nuclear DEAD box RNA helicase in the spruce budworm, Choristoneura fumiferana.

RNA helicases play important roles in cellular processes such as pre-mRNA splicing, rRNA processing, ribosomal biogenesis, and translation. A full-length DEAD box RNA helicase cDNA (CfrHlc113) was isolated from the spruce budworm, Choristoneura fumiferana. CfrHlc113 contained the eight functional motifs, which are highly conserved in the DEAD box RNA helicase family, and an arginine-serine-aspartate (RSD) domain at its N-terminal end. CfrHlc113 was highly homologous to Rattus norvegicus HEL117 and human prp5 genes, both of which are suggested to be involved in RNA splicing. The results of Northern and Western blotting showed that expression of the CfrHlc113 gene was low or undetectable in eggs, larvae, pupae, and adults. High levels of expression were, however, detected in the three in vitro cultured cell lines, CF-203, CF-124T, and CF-70, which were developed from the midgut, ovaries, and neonate larvae, respectively. Immunocytochemistry revealed that CfrHlc113 protein was present exclusively in the nuclei of these cell lines.

Cloning and expression of a putative transferrin cDNA of the spruce budworm, Choristoneura fumiferana.

A spruce budworm (Choristoneura fumiferana) transferrin cDNA (CfTf) was isolated and cloned from a cDNA library that was constructed using mRNA from fifth to sixth instar larvae. CfTf cDNA encoded a predicted protein of 681 amino acids with a molecular mass of approximately 76 kDa. CfTf shared 72% and 74% identities at the amino acid level with transferrins of Manduca sexta and Bombyx mori, respectively. Like other transferrins, CfTf retains most of the N-terminal, iron-binding amino acid residues. Northern blot analyses indicated that CfTf mRNA was present at high levels after ecdysis, but that the expression level was low prior to ecdysis at the fourth-sixth instar stages. The highest level of CfTf expression was detected in the fat body. Relatively low levels of expression were detected in the epidermis and no expression was found in the midgut. Expression of CfTf mRNA could be induced by bacteria but not fungi. Expression of CfTf mRNA was suppressed by iron load.

Hierarchically biomimetic bone scaffold materials: nano-HA/collagen/PLA composite.

A bone scaffold material (nano-HA/ collagen/PLA composite) was developed by biomimetic synthesis. It shows some features of natural bone both in main composition and hierarchical microstructure. Nano-hydroxyapatite and collagen assembled into mineralized fibril. The three-dimensional porous scaffold materials mimic the microstructure of cancellous bone. Cell culture and animal model tests showed that the composite material is bioactive. The osteoblasts were separated from the neonatal rat calvaria. Osteoblasts adhered, spread, and proliferated throughout the pores of the scaffold material within a week. A 15-mm segmental defect model in the radius of the rabbit was used to evaluate the bone-remodeling ability of the composite. Combined with 0.5 mg rhBMP-2, the material block was implanted into the defect. The segmental defect was integrated 12 weeks after surgery, and the implanted composite was partially substituted by new bone tissue. This scaffold composite has promise for the clinical repair of large bony defects according to the principles of bone tissue engineering.

An ecdysone-inducible putative "DEAD box" RNA helicase in the spruce budworm (Choristoneura fumiferana).

RNA helicases are a family of enzymes that unwind nucleic acid duplexes, such as RNA/RNA and RNA/DNA, in a 3' to 5' direction into single-stranded polynucleotides. A putative RNA helicase cDNA (CfrHlc64) was isolated from the spruce budworm, Choristoneura fumiferana. CfrHlc64 was 1998 nucleotides in length, and the deduced protein had 565 amino acids with a predicted molecular mass of 64 kDa. It contained eight functional motifs conserved in the "DEAD box" family of RNA helicases. The deduced amino acid sequence showed 10-50% identities to homologues of other species from bacteria to human. In vitro expression of the cDNA resulted in recombinant proteins of 64 kDa as expected from the deduced amino acid sequence. Northern blotting and RT-PCR analyses revealed the presence of CfrHlc64 mRNA in all developmental stages from embryo to adult. Higher levels of CfrHlc64 mRNA were detected in the fat body and midgut than in the epidermis of sixth instar larvae. The CfrHlc64 protein was distributed mainly in the fat body. Female adults expressed CfrHlc64 mRNA at higher levels than male adults. The nonsteroidal ecdysone agonist, tebufenozide, enhanced the expression of CfrHlc64 in a dose-dependent manner.

Covalent immobilization of chitosan and heparin on PLGA surface.

Chitosan and heparin were covalently immobilized onto a poly(lactic acid-co-glycolic acid) (PLGA) surface using N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC), N-hydroxysuccinimide (NHS) in a 2-morpholinoethane sulfonic acid (MES) buffer system. The properties of the modified PLGA surface and the control were investigated by water contact angle measurement and electron spectroscopy for chemical analysis (ESCA). The water contact angle of the modified film was greatly decreased and the element content on the surface of the films changed correspondingly. Platelet adhesion assay showed that blood compatibility of the chitosan/heparin modified film was improved while hepatocyte culture indicated that the cell compatibility of the modified film was enhanced.

Temporal, spatial and induced expression of chitinase in the spruce budworm, Choristoneura fumiferana.

Temporal, spatial and induced expression of Choristoneura fumiferana chitinase (CfChitinase) was studied using immunohistochemistry and Western blots. CfChitinase was detected in the integument, the midgut peritrophic membrane, the cuticular lining of the trachea, the spiracle, and salivary glands. The enzyme was expressed as larvae were preparing to molt from one instar to the next. The spatial and temporal expression patterns are consistent with its function in degrading chitin during the molting process. The 20-hydroxyecdysone agonist, tebufenozide (RH5992), induced the expression of the CfChitinase gene in the early stage of the sixth-instar larvae and the enzyme was detected in the epidermis and molting fluid 24 h post treatment.

Crosslinked collagen/chitosan matrix for artificial livers.

Matrices composed of collagen and chitosan may create an appropriate environment for the regeneration of livers. In this study, we have prepared, characterized and evaluated a new collagen/chitosan matrix (CCM). The CCM was made by using crosslinking agent 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) in N-hydroxysuccinimide (NHS) and a 2-morpholinoethane sulfonic acid (MES) buffer system. The chemical characteristics were evaluated by Fourier-transformed infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The mechanical strength was measured by tensile tests. The platelet deposition and hepatocyte culture experiments show that CCM has excellent blood and cell compatibility. The results suggest that the CCM is a promising candidate matrix for implantable bioartificial livers.

Mechanical properties of skeletal bone in gene-mutated stöpsel(dtl28d) and wild-type zebrafish (Danio rerio) measured by atomic force microscopy-based nanoindentation.

An atomic force microscopy (AFM)-based nanoindenter was used to evaluate the mechanical properties of skeletal bones in wild-type and gene-mutated zebrafish (Danio rerio), stöpsel(dtl28d). Both skeletons were isolated from adult zebrafish and tested under a load of 5 mN. It was found that stp/stp bone has a similar nanohardness but significantly greater elastic modulus compared with that of wild-type bone. The residual indenter impressions using AFM and the fracture surfaces of both bones using scanning electron microscopy were examined and showed that the bone of zebrafish becomes more brittle after the stp mutation. This first observation of the alteration of bone mechanical behavior by gene mutation in zebrafish system is of scientific and clinical relevance to many areas of study, such as bone fracture and fragility mechanisms in human heritable disorders and bone-materials fabrication via gene engineering.