Incidence, management and mortality of acute hypoxemic respiratory failure and acute respiratory distress syndrome from a prospective study of Chinese paediatric intensive care network

AIM

To investigate the incidence, clinical management, mortality and its risk factors, major outcome and costs of acute hypoxemic respiratory failure (AHRF) and acute respiratory distress syndrome (ARDS) in a Chinese network of 26 paediatric intensive care unit (PICU).

METHODS

In a consecutive 12-month period, AHRF and ARDS were identified and followed up for 90 days or until death or discharge.

RESULTS

From a total of 11 521 critically ill patients, 461 AHRF were identified in which 306 developed ARDS (66.4%), resulting in incidences of 4% and 2.7%, respectively, with pneumonia (75.1%) and sepsis (14.7%) as main underlying diseases and 83% were 5 years and 1 month-old. In-hospital mortality of AHRF was 41.6% (44.8% for ARDS), accounted for 15.5% of all PICU deaths. For those of pneumonia or sepsis with AHRF and ARDS, mortality and its relative risk were significantly higher than those without. Relatively lower tidal volume and total fluid balance, adequate upper limit of PaCO(2) in the early PICU days, and family affordability, tended to result in better outcome.

CONCLUSION

In this prospective study, AHRF had high possibilities to develop ARDS and death risk, as impacted by ventilation settings and fluid intake in the early treatment, as well as socioeconomic factors, which should be considered for implementation of standard of care in respiratory therapy.

Substrate specificity of family 5, 6, 7, 9, 12, and 45 endoglucanases

Endoglucanases are important enzymes for biomass conversion and other industrial processes. Determining the specificity of endoglucanases from various glycoside hydrolase families is of interest for bioinformatic functional prediction and substrate-tailored enzyme development. To do so, we characterized approximately 30 endoglucanases from six glycoside hydrolase families. For p-nitrophenyl cellobioside and lactoside, only family 7 enzymes showed significant activity. For xyloglucan, both family 7 and 12 enzymes showed significant activity. For xylan and arabinoxylan, only family 7 enzymes showed significant activity. For mannan and galactomannan, both family 5 and 9 enzymes showed significant activity. The difference in specificity was preliminarily attributed mainly to the structural difference of the enzymes' active sites. For family 7 endoglucanases, difference in thermal stability might affect their performance in hydrolyzing various (hemi)cellulose substrates. Phylogenetic analysis on the subfamily distribution of family 5 endoglucanases (in relation with mannanases) suggested that their mannanase side-activity might be the remnant of an ancestral multi-function enzyme. Similar analysis was also made with the xyloglucanase or arabionxylans side-activity of family 12 and 7 endoglucanases. The apparent dependence of the specificity on family (primary/tertiary structure) might assist us in better understanding the structure-function relationship of the enzymes, and developing more versatile biocatalysts for the utilization of biomass.

A droplet-based building block approach for bladder smooth muscle cell (SMC) proliferation

Tissue engineering based on building blocks is an emerging method to fabricate 3D tissue constructs. This method requires depositing and assembling building blocks (cell-laden microgels) at high throughput. The current technologies (e.g., molding and photolithography) to fabricate microgels have throughput challenges and provide limited control over building block properties (e.g., cell density). The cell-encapsulating droplet generation technique has potential to address these challenges. In this study, we monitored individual building blocks for viability, proliferation and cell density. The results showed that (i) SMCs can be encapsulated in collagen droplets with high viability (>94.2 +/- 3.2%) for four cases of initial number of cells per building block (i.e. 7 +/- 2, 16 +/- 2, 26 +/- 3 and 37 +/- 3 cells/building block). (ii) Encapsulated SMCs can proliferate in building blocks at rates that are consistent (1.49 +/- 0.29) across all four cases, compared to that of the controls. (iii) By assembling these building blocks, we created an SMC patch (5 mm x 5 mm x 20 microm), which was cultured for 51 days forming a 3D tissue-like construct. The histology of the cultured patch was compared to that of a native rat bladder. These results indicate the potential of creating 3D tissue models at high throughput in vitro using building blocks.

Dynamics of microRNA-mediated motifs

In the past, most research on gene regulation has focused on transcriptional regulation and post-translational regulation. Recently, the post-transcriptional regulation by small non-coding RNAs has drawn much attention. This mode of regulation was found in both prokaryotes and eukaryotes. In this study, the authors integrate transcriptional and post-transcriptional regulation into four different kinds of microRNA-mediated motifs and investigate the mechanism of microRNAs regulation from the viewpoints of dynamics. Theoretical analysis and numerical simulations show that all the four motifs exhibit strong robustness to external and stochastic perturbations.

Strain rate sensitivity of skin tissue under thermomechanical loading

There have been limited studies addressing the thermally dependent mechanical properties of skin tissue, although this can contribute to a variety of medical applications. To address this, an experimental study on the tensile behaviour of pig skin tissue under different thermal loading conditions and different mechanical stretching rates was performed. The results indicate that there is a significant variation among skin tensile behaviours under different temperatures and loading rates, which is correlated with dermal collagen denaturation. The Ogden model was used to summarize the effect of the strain rate and the temperature upon the measured constitutive response through two parameters (alpha and mu). These results can be used in future models to improve clinical thermal treatments for skin tissue.

Development of boron-efficient near isogenic lines of Brassica napus and their response to low boron stress at seedling stage

Rapeseed (Brassica napus) is sensitive to low boron (B) stress and plentiful variation exists in response to B deficiency. One major QTL, BE1, and three minor loci controlling B efficiency in Brassica napus were previously detected. To fine map and clone the B-efficient gene (s), the development of B-efficient NILs in Brassica napus was conducted, combining the identification of B efficiency at seedling stage with genetic background selection using random AFLP markers. The molecular marker assisted background selection proved its optimum and necessary in an early backcrossing generation to select the backcross individuals with high genetic background similarity to accelerate the construction of NILs. Based on B efficiency investigated at seedling stage under the low B conditions, the B-efficient backcross line can produce biomass twice about the B-inefficient parent's and show low B concentration and effective utilization of B under low B condition. Thus, the B efficiency of the B efficient NILs might be attributed to the higher B utilization efficiency or less demand for B.

Molecular and enzymatic profiles of mammalian DNA methyltransferases: structures and targets for drugs

DNA methylation is an epigenetic event involved in a variety array of processes that may be the foundation of genetic phenomena and diseases. DNA methyltransferase is a key enzyme for cytosine methylation in DNA, and can be divided into two functional families (Dnmt1 and Dnmt3) in mammals. All mammalian DNA methyltransferases are encoded by their own single gene, and consisted of catalytic and regulatory regions (except Dnmt2). Via interactions between functional domains in the regulatory or catalytic regions and other adaptors or cofactors, DNA methyltransferases can be localized at selective areas (specific DNA/nucleotide sequence) and linked to specific chromosome status (euchromatin/heterochromatin, various histone modification status). With assistance from UHRF1 and Dnmt3L or other factors in Dnmt1 and Dnmt3a/Dnmt3b, mammalian DNA methyltransferases can be recruited, and then specifically bind to hemimethylated and unmethylated double-stranded DNA sequence to maintain and de novo setup patterns for DNA methylation. Complicated enzymatic steps catalyzed by DNA methyltransferases include methyl group transferred from cofactor Ado-Met to C5 position of the flipped-out cytosine in targeted DNA duplex. In the light of the fact that different DNA methyltransferases are divergent in both structures and functions, and use unique reprogrammed or distorted routines in development of diseases, design of new drugs targeting specific mammalian DNA methyltransferases or their adaptors in the control of key steps in either maintenance or de novo DNA methylation processes will contribute to individually treating diseases related to DNA methyltransferases.

Activity identification of chimeric anti-caspase-3 mRNA hammerhead ribozyme in vitro and in vivo

To study the expression activity of various vectors containing anti-caspase-3 ribozyme cassettes in vivo, and to further study the role of caspas-3 in the apoptotic pathway, we constructed anti-caspase-3 hammerhead ribozyme embedded into the human snRNA U6, and detected the activity of the ribozyme in vitro and in vivo. Meanwhile we compared it with the self-cleaving hammerhead ribozymes that we previously studied, and with the general ribozyme, cloned into RNA polymerase II expression systems. The results showed that the three ribozymes, p1.5RZ107, pRZ107 and pU6RZ107 had the correct structure, and that they could cleave caspase-3 mRNA exactly to produce two fragments: 143nt/553nt. p1.5RZ107 has the highest cleavage efficiency in vitro, almost 80%. However, the U6 chimeric ribozyme, pU6RZ107, has the highest cleavage activity in vivo, almost to 65%, though it has lower cleavage activity in vitro. The cleavage results demonstrated that the pU6RZ107, the U6 chimeric ribozyme, could more efficiently express and downregulate the level of caspase-3 in vivo, and the ribozyme could provide an alternative approach to the research into the mechanism of apoptosis and human gene therapy also.

A cross-sectional study of dentine hypersensitivity in China

OBJECTIVE

To carry out a cross-sectional study of the prevalence of dentine hypersensitivity and related risk factors in Chengdu City, China.

METHODS

A total of 1,320 subjects were distributed equally in six communities in Chengdu City and of all age groups (10 years for an age group) including the same number of male and female subjects in each community. Each subject completed a structured interview and the subjects who reported hypersensitivity were examined further using a triple syringe to administer a blast of cold air to confirm the diagnosis of dentine hypersensitivity. Periodontal attachment loss and gingival recession of all sensitive teeth were measured.

RESULTS

The prevalence of dentine hypersensitivity was 25.5% in the oral test. Only 16.6% of subjects who reported hypersensitivity symptoms had received desensitising treatment. 50-59 year age group was the cohort with the greatest number of subjects with DH and the premolar was the most commonly affected tooth. Low education level, gingival recession, and attachment loss were related to dentine hypersensitivity.

CONCLUSIONS

The prevalence of dentine hypersensitivity in an urban adult population in Chengdu City was 25.5%.

Functional gene silencing mediated by chitosan/siRNA nanocomplexes

Chitosan/siRNA nanoparticles to knock down FHL2 gene expression were reported in this work. The physicochemical properties such as particle size, surface charge, morphology and complex stability of chitosan nanoparticle-incorporated siRNA were evaluated. Nanoparticles which were formulated with chitosan/siRNA exhibited irregular, lamellar and dendritic structures with a hydrodynamic radius size of about 148 nm and net positive charges with zeta-potential value of 58.5 mV. The knockdown effect of the chitosan/siRNA nanoparticles on gene expression in FHL2 over-expressed human colorectal cancer Lovo cells was investigated. The result showed that FHL2 siRNA formulated within chitosan nanoparticles could knock down about 69.6% FHL2 gene expression, which is very similar to the 68.8% reduced gene expression when siRNA was transfected with liposome Lipofectamine. Western analysis further showed significant FHL-2 protein expression reduced by the chitosan/siRNA nanoparticles. The results also showed that blocking FHL2 expression by siRNA could also inhibit the growth and proliferation of human colorectal cancer Lovo cells. The current results demonstrated that chitosan-based siRNA nanoparticles were a very efficient delivery system for siRNA in vivo as previously reported.

CIGARETTE SMOKE-INDUCED HYPERCAPNIC EMPHYSEMA IN C3H MICE IS ASSOCIATED WITH INCREASES OF MACROPHAGE METALLOELASTASE AND SUBSTANCE P IN THE LUNGS

The authors tested whether macrophage metalloelastase (MMP-12) and substance P (SP) were increased in the cigarette smoke (CS)-exposed female C3H/HeN mice with hypercapnic emphysema. The authors found that as compared to control (filtered air), 16 weeks of CS exposure significantly up-regulated mRNA and protein levels of MMP-12, the ratio of MMP-12/tissue inhibitor of matrix metalloproteinase-1, and SP/preprotachykinin-A (a precursor to SP) in the lungs. Importantly, a significant correlation was found between MMP-12 and SP, and between MMP-12/SP and the degrees of hypoxemia/hypercapnia denoted in CS-exposed mice. These data suggest a possible involvement of SP and MMP-12 in the pathogenesis of severe COPD.

Final STEPP results of prophylacatic versus reactive skin toxicity (ST) treatment (tx) for panitumumab (pmab)-related ST in patients (pts) with metastatic colorectal cancer (mCRC)

CRA4027

Background: Pmab, a fully human monoclonal antibody targeting the epidermal growth factor receptor (EGFR), is approved as monotherapy in the US for mCRC following disease progression (PD) and in the EU and Canada for tumors bearing wild-type (WT) KRAS. The most common toxicity with anti-EGFR inhibitors are ST. This study of pmab+ chemotherapy (CT) estimates the difference in the incidence of specific ≥ grade 2 ST of interest between pts receiving prophylactic (P) or reactive (R) skin tx. Methods: Pts had unresectable mCRC after PD with 1st-line fluoropyrimidine and oxaliplatin-based CT ± bevacizumab. Pts received either pmab 6.0mg/kg/FOLFIRI Q2W or pmab 9 mg/kg/irinotecan Q3W. Within each stratum, pts were randomized 1:1 to either P ST tx 24 hrs before the 1st dose daily for 6 wks or R ST tx after ST occurred. Tx for ST included: moisturizers, sunscreen, topical steroid, and doxycycline. Efficacy and safety were evaluated by P vs R tx groups, KRAS status (mutant [MT] vs WT), and chemotherapy status. Responses were assessed using modified RECIST with confirmation. Quality of life was assessed using the Dermatology Life Quality Index at screening, wks 2–7, and follow-up. Results: 95 pts were enrolled and randomized: 48 pts to P and 47 pts to R. During the 6 wk ST tx period, 29% of pts in the P group vs 62% of pts in the R group had protocol-specified ≥grade 2 ST. Of the 87 KRAS evaluable pts, 49 (56%) pts had WT KRAS and 38 (44%) pts had MT KRAS. Efficacy and safety are shown. Mean (SD) change in DLQI from baseline was 1.3 (2.6) for P and 4.2 (5.8) for R at wk 3 (when the median time to 1st ≥grade 2 ST was reached in the R group) and was 2.0 (2.8) for P and 2.6 (4.4) for R at wk 7. Conclusions: Prophylactic use of the skin tx regimen resulted in >50% reduction in the rate of specific ≥ grade 2 STs and improved QOL during the 6-week skin tx period vs R use. Numerical differences in favor of the P group were observed for all endpoints.

[Table: see text]

[Table: see text]

Thermally-Induced Change in the Relaxation Behavior of Skin Tissue

Skin biothermomechanics is highly interdisciplinary, involving bioheat transfer, burn damage, biomechanics, and physiology. Characterization of the thermomechanical behavior of skin tissue is of great importance and can contribute to a variety of medical applications. However, few quantitative studies have been conducted on the thermally-dependent mechanical properties of skin tissue. The aim of the present study is to experimentally examine the thermally-induced change in the relaxation behavior of skin tissue in both hyperthermal and hypothermic ranges. The results show that temperature has great influence on the stress-relaxation behavior of skin tissue under both hyperthermal and hypothermic temperatures; the quantitative relationship that has been found between temperature and the viscoelastic parameter (the elastic fraction or fractional energy dissipation) was temperature dependent, with greatest dissipation at high temperature levels.

Final STEPP results of prophylacatic versus reactive skin toxicity (ST) treatment (tx) for panitumumab (pmab)-related ST in patients (pts) with metastatic colorectal cancer (mCRC)

CRA4027

The full, final text of this abstract will be available in Part II of the 2009 ASCO Annual Meeting Proceedings, distributed onsite at the Meeting on May 30, 2009, and as a supplement to the June 20, 2009, issue of the Journal of Clinical Oncology.

[Table: see text]

Safety summary of panitumumab (pmab) in combination with chemotherapy (ctx) from four clinical trials in patients (pts) with metastatic colorectal cancer (mCRC)

e15005

Background: Pmab is a fully human anti-epidermal growth factor receptor (EGFR) monoclonal antibody approved in the US and EU (wild-type KRAS) as monotherapy for pts with mCRC. Safety data from 4 studies (Siena et al ASCO 2008; Peeters et al ASCO 2008; Cohn et al ASCO 2008; Mitchell et al WORLD GI 2008) of pmab in combination with ctx are summarized. Methods: Two studies are single-arm, phase II trials and two are randomized, phase III trials with pooled, blinded safety data that include ctx-controls. All studies were multicenter. Common pt eligibility criteria included: diagnosis of mCRC with measurable disease per modified RECIST criteria, age ≥ 18 years, and adequate hematologic, renal, hepatic, and metabolic function. All studies required pts to receive FOLFOX, FOLFIRI, or irinotecan ctx in combination with pmab. Pts received pmab 6.0 mg/kg Q2W with FOLFOX Q2W or FOLFIRI Q2W, or pmab 9.0 mg/kg Q3W with irinotecan Q3W. Results from planned interim analyses are available for 3 studies, and results from the final analysis are available for one study. Results: Among the 4-study safety data, 1213 pts received pmab + ctx; 703 pts received pmab + FOLFIRI, 455 pts received pmab + FOLFOX, and 55 pts received pmab + irinotecan. Approximately 1,200 pts were enrolled in each phase III study, and data are available from 1,003 pts who received pmab + ctx and 997 pts who received ctx alone. All pts in the phase III studies, regardless of treatment group, were included in the pooled, blinded interim analysis sets monitored by the data monitoring committee for each study. Safety results for the two phase II studies of pmab + ctx and two phase III studies of pmab ± ctx are summarized (Table). Conclusions: Phase II data are consistent with expectations, and phase III trials are ongoing. A consistent safety profile was observed across studies.

[Table: see text]

[Table: see text]