Cellular Toxicity of Various Inhalable Metal Nanoparticles on Human Alveolar Epithelial Cells

Nanoparticles (NPs) have a greater potential to travel through an organism via inhalation than any other larger particles, and could be more toxic due to their larger surface area and specific structural/chemical properties. The aim of this study was to evaluate in vitro biological effects of various inhalable metallic NPs (TiO2, Ag, Al, Zn, Ni). Human alveolar epithelial cells (A549) were exposed to various concentrations of NPs for 24 h. The extent of morphological damage was in the order of m-TiO2 > n-TiO2 > m-silica >> n-Ni approximately = n-Zn approximately = n-Ag approximately = n-Al and was affected in a dose-dependent manner. The extent of apoptotic damage measured with two-color flow cytometry was in the order of n-Zn > n- Ni > m-silica >> n- TiO2 > m- TiO2 > n-Al > n-Ag. The extent of apoptotic damage measured with DNA fragmentation was in the order of n-Zn approximately = m-silica > n- Ni >> m- TiO2 approximately = n- TiO2 approximately = n-Al > n-Ag, indicating no significant difference in the damages by both m-TiO2 and n-TiO2. The extents of apoptotic damages were also affected in a dose-dependent manner. Uptake of no other NPs but n-TiO2 and m-TiO2 into the cells was observed after 24 h exposure. The intracellular generation of ROS was significant with n-Zn but not with the other particles. These results demonstrated that various inhalable metallic NPs (TiO2, Ag, Al, Zn, Ni) could cause cell damages directly or indirectly. More detailed studies on the influence of size, structure, and composition of the NPs are needed to better understand their toxic mechanisms.

Autophagy deficiency in beta cells leads to compromised unfolded protein response and progression from obesity to diabetes in mice

AIMS/HYPOTHESIS

The unfolded protein response (UPR) in endoplasmic reticulum (ER) and autophagy are known to be related. We investigated the role of autophagy in UPR of pancreatic beta cells and the susceptibility of autophagy-deficient beta cells to the ER stress that is implicated in the development of diabetes.

METHODS

Rat insulin promoter (RIP)-Cre(+);autophagy-related 7 (Atg7)(F/W) mice were bred with ob/w mice to derive RIP-Cre(+);Atg7(F/F)-ob/ob mice and to induce ER stress in vivo. GFP-LC3(+)-ob/ob mice were generated to examine in vivo autophagic activity. Real-time RT-PCR was performed to study the expression of the genes of the UPR machinery. Proteolysis was assessed by determining release of incorporated radioactive leucine.

RESULTS

Production of UPR machinery was reduced in autophagy-deficient beta cells, which was associated with diminished production of p85α and p85β regulatory subunits of phosphoinositide 3-kinase. Because of compromised UPR machinery, autophagy-deficient beta cells were susceptible to ER stressors in vitro. When mice with beta cell-specific autophagy deficiency, which have mild hyperglycaemia, were bred with ob/ob mice to induce ER stress in vivo, severe diabetes developed, which was accompanied by an increase in beta cell death and accumulation of reactive oxygen species. The increased demand for UPR present in obesity was unmet in autophagy-deficient beta cells. Autophagy level and autophagic activity were enhanced by lipid, while proteolysis was reduced.

CONCLUSIONS/INTERPRETATION

These results suggest that autophagy is important for intact UPR machinery and appropriate UPR in response to lipid injury that increases demand for UPR. Autophagy deficiency in pancreatic beta cells may contribute to the progression from obesity to diabetes.

Evaluation of ease of intubation with the GlideScope�or Macintosh laryngoscope by anaesthetists in simulated easy and difficult laryngoscopy

The GlideScope is a new video laryngoscope developed for management of the difficult airway. We compared the GlideScope with the Macintosh laryngoscope in simulated easy and difficult laryngoscopy. Twenty anaesthetists were allowed three attempts to intubate in each of four laryngoscopy scenarios in a high fidelity simulator. In the simulated easy laryngoscopy scenarios, the anaesthetists took longer to intubate using the GlideScope than the Macintosh laryngoscope (mean (SD) 19.0 (9.7) s vs. 12.7 (5.9) s, respectively; p = 0.006). There was no difference in the number of successful intubations, ease of intubation or choice of intubating device. In the simulated difficult laryngoscopy scenarios, the anaesthetists took less time to intubate using the GlideScope (23.5 (12.7) s vs. 70.5 (101.2) s, respectively; p = 0.001). The slightly higher success rate with the GlideScope was not statistically significant (20/20 vs. 18/20, respectively; p = 0.5). However, the anaesthetists found it easier to intubate using the GlideScope (median (interquartile range [range]) 1 (1-2 [1-2]) vs. 2 (2-3 [1-3]), respectively; p < 0.0001).

Investigation of the roles of toxin-coregulated pili and mannose-sensitive hemagglutinin pili in the pathogenesis of Vibrio cholerae O139 infection

In this study, adult volunteers were fed tcpA and mshA deletion mutants of V. cholerae O139 strain CVD 112 to determine the role of toxin-coregulated pili (TCP) and mannose-sensitive hemagglutinin (MSHA) in intestinal colonization. Eight of 10 volunteers who received CVD 112 or CVD 112 delta mshA shed the vaccine strains in their stools; the geometric mean peak excretion for both groups was 1.4 x 10(5) CFU/g of stool. In contrast, only one of nine recipients of CVD 112 delta tcpA shed vibrios in his stool (P < 0.01); during the first 24 h after inoculation, 3 x 10(2) CFU/g was recovered from this volunteer. All recipients of CVD 112 and 8 (80%) of the recipients of CVD 112 delta mshA developed at least a fourfold rise in vibriocidal titer after immunization. In contrast, only one (11%) of the nine recipients of CVD 112 delta tcpA developed a fourfold rise in vibriocidal titer (P < 0.01). We conclude that TCP are an important colonization factor of V. cholerae O139 and probably of El Tor V. cholerae O1. In contrast, MSHA does not appear to promote intestinal colonization in humans.

CAS agar diffusion assay for the measurement of siderophores in biological fluids

We developed a simple and universal method, by modifying the universal CAS (Chrome azurol S) assay, measuring siderophores in various biological fluids. We named the assay as CAS agar diffusion (CASAD) assay. CAS plate devoid of nutrients was prepared by using Bacto-agar (1.5%, w/v) as a matrix. Holes with 5-mm-diameter were punched on the CAS agar plate. Each hole was added by 35 microl of the test fluids containing Desferal that was twofold serially diluted. After incubating at 37 degrees C or room temperature for 4-8 h, the size of orange haloes formed around the holes was measured. The size of orange haloes correlated well with the concentration of Desferal in all the biological fluids tested in this study. CASAD assay showed consistent results in wide pH range from 5 to 9. Addition of iron to the test fluids containing Desferal decreased the size of orange haloes in a dose-dependent manner, which suggests that the CASAD assay detects only iron non-bound siderophore. These results suggest that CASAD assay would serve as a simple, stable, and highly reproducible test for screening and quantitative siderophore analysis in biological fluids.

Distinct FAK-Src activation events promote alpha5beta1 and alpha4beta1 integrin-stimulated neuroblastoma cell motility

Signals from fibronectin-binding integrins promote neural crest cell motility during development in part through protein-tyrosine kinase (PTK) activation. Neuroblastoma (NB) is a neural crest malignancy with high metastatic potential. We find that alpha4 and alpha5 integrins are present in late-stage NB tumors and cell lines derived thereof. To determine the signaling connections promoting either alpha4beta1- or alpha5beta1-initiated NB cell motility, pharmacological, dominant negative and short-hairpin RNA (shRNA) inhibitory approaches were undertaken. shRNA knockdown revealed that alpha5beta1-stimulated NB motility is dependent upon focal adhesion kinase (FAK) PTK, Src PTK and p130Cas adapter protein expression. Cell reconstitution showed that FAK catalytic activity is required for alpha5beta1-stimulated Src activation in part through direct FAK phosphorylation of Src at Tyr-418. Alternatively, alpha4beta1-stimulated NB cell motility is dependent upon Src and p130Cas but FAK is not essential. Catalytically inactive receptor protein-tyrosine phosphatase-alpha overexpression inhibited alpha4beta1-stimulated NB motility and Src activation consistent with alpha4-regulated Src activity occurring through Src Tyr-529 dephosphorylation. In alpha4 shRNA-expressing NB cells, alpha4beta1-stimulated Src activation and NB cell motility were rescued by wild type but not cytoplasmic domain-truncated alpha4 re-expression. These studies, supported by results using reconstituted fibroblasts, reveal that alpha4beta1-mediated Src activation is mechanistically distinct from FAK-mediated Src activation during alpha5beta1-mediated NB migration and support the evaluation of inhibitors to alpha4, Src and FAK in the control of NB tumor progression.

A Comparison of the GlideScope® with the Macintosh Laryngoscope for Tracheal Intubation in Patients with Simulated Difficult Airway

We compared the use of the GlideScope® and the conventional Macintosh laryngoscope in a simulated difficult airway. The primary hypothesis was that time to intubation would be shorter using the GlideScope® than using the Macintosh laryngoscope.

After obtaining approval from the ethics committee and written informed consent, we recruited 60 ASA 1 and 2 patients to our randomized controlled trial. Group G (n=30) had tracheal intubation performed using the GlideScope® and Group M (n=30) were intubated using a Macintosh laryngoscope. We simulated a difficult airway in each patient by having an experienced assistant provide in-line manual stabilization of the head and neck. We recorded the best laryngeal view; difficulty of the tracheal intubation; time taken for successful tracheal intubation; manoeuvre needed to aid tracheal intubation and complications associated with the tracheal intubation.

The median Cormack and Lehane grade was significantly better in Group G than Group M. Group G had a significantly shorter intubation time than group M (mean 41.8s±SD 20.2 vs mean 56.2s±26.6, P<0.05).

The GlideScope® improved the laryngeal view and decreased time for tracheal intubation time when compared with the Macintosh laryngoscope in patients with simulated difficult airway. The GlideScope® may be a good alternative for managing the difficult airway but clinical trials evaluating its use on patients with an actual difficult airway are needed.

Incidence and risk factors for chronic pain after caesarean section under spinal anaesthesia

This study investigated the incidence and risk factors associated with chronic pain after elective caesarean section under spinal anaesthesia in an Asian population. A prospective cohort study was conducted among subjects who underwent elective caesarean section under spinal anaesthesia, with morphine patient-controlled analgesia administered for 24 hours postoperatively. Perioperative, surgical and obstetric factors were investigated prospectively. Phone surveys were conducted to identify risk factors associated with chronic pain. A total of 857 subjects completed both the perioperative study and phone survey. The incidence of wound scar pain for three months after surgery was 9.2% (79). Of the 51 subjects with persistent pain at the time of subsequent survey, 9.8% (n = 5) had constant pain, 9.8% (n = 5) had daily pain and 23.5% (n = 12) had pain intermittently, at an interval of days. The independent risk factors for development of chronic pain were higher pain scores recalled in the immediate postoperative period (odds ratio [OR, 95% confidence interval] 1.348 [1.219 to 1.490], P = 0.0001), pain present elsewhere (OR 2.471 [1.485 to 4.112], P = 0.001) and non-private insurance status (OR 1.679 [1.034 to 2.727], P = 0.036). The two most common sites of pain other than wound pain were back pain (n = 316) and migraine (n = 87).

Automated regular boluses for epidural analgesia: a comparison with continuous infusion

BACKGROUND

Intermittent epidural bolus dosing is a method of drug delivery that can prolong the duration of labour analgesia induced by a combined spinal epidural (CSE). In this randomized, double-blinded study, we compared the analgesic efficacy of two drug delivery systems: regular intermittent epidural boluses and continuous epidural infusion and assessed the incidence of breakthrough pain after CSE.

METHODS

With the approval of the Hospital Ethics Committee, we recruited 60 parturients into this randomized controlled trial. A CSE was performed with intrathecal fentanyl 25 mug in all patients. The parturients were then randomly allocated into two groups. The infusion group received a continuous epidural infusion of levobupivacaine 0.1% with fentanyl 2 microg/mL at a rate of 10 mL/h. The bolus group received 5-mL epidural boluses every half hour. The sample size was computed to detect a 40% reduction in the rate of breakthrough pain.

RESULTS

The bolus group had a lower incidence of breakthrough pain than the infusion group (10% vs. 37%, P < 0.05). The bolus group also had significantly higher satisfaction scores for labour analgesia: 97+/-8 (mean+/-SD) vs. 89+/-7 (P < 0.05).

CONCLUSION

Automated regular bolus delivery of epidural analgesia when compared with continuous infusion decreased the incidence of breakthrough pain and increased maternal satisfaction. In a busy obstetric unit, this may also serve to decrease the anesthetists' workload.

Changes in DNA 8-hydroxyguanine levels, 8-hydroxyguanine repair activity, and hOGG1 and hMTH1 mRNA expression in human lung alveolar epithelial cells induced by crocidolite asbestos

We examined 8-hydroxyguanine (8-OH-Gua) formation and 8-OH-Gua repair enzyme activity in pulmonary type-II-like epithelial cells to determine whether oxidative stress induced by asbestos plays a role in its carcinogenic mechanism. A549 cells were incubated with crocidolite asbestos at concentrations of 0, 10, 50 and 100 microg/ml over 27 h. We then evaluated 8-OH-Gua formation, 8-OH-Gua repair enzyme activity and gene expression of 8-oxoguanine-DNA glycosylase 1 (hOGG1) and human MUtT homologue (hMTH1). This was done using a high-performance liquid chromatography system equipped with an electrochemical detector, endonuclease nicking assay and reverse transcription polymerase chain reaction, respectively. Crocidolite induced the formation of 8-OH-Gua in DNA at concentrations of 50 and 100 microg/ml. 8-OH-Gua levels increased at 9 h and had declined to near baseline at 27 h, whereas 8-OH-Gua repair enzyme activity peaked at 18 h post-crocidolite exposure. hOGG1 and hMTH1 mRNA levels were also increased by crocidolite exposure. These data suggest that crocidolite asbestos is associated with epithelial cell injury in the process of carcinogenesis through oxidative stress.

A randomized comparison of automated intermittent mandatory boluses with a basal infusion in combination with patient-controlled epidural analgesia for labor and delivery

BACKGROUND

Automated mandatory boluses (AMB), when used in place of a continuous basal infusion, have been shown to reduce overall local anesthetic consumption without compromising analgesic efficacy in patient-controlled epidural analgesia (PCEA). We hypothesized that our PCEA+AMB regimen could result in a reduction of breakthrough pain requiring epidural supplementation in comparison with PCEA with a basal infusion (PCEA+BI).

METHODS

We recruited sixty-two healthy ASA I nulliparous parturients in early labor. The parturients were randomized to receive 0.1% ropivacaine+fentanyl 2 μg/mL either via PCEA+BI (PCEA with basal continuous infusion of 5mL/h) or PCEA+AMB (PCEA with AMB of 5 mL every hour instead of a basal infusion) immediately following successful induction of combined spinal-epidural (CSE) analgesia. Block characteristics, incidence of breakthrough pain requiring epidural supplementation, side effects, obstetric outcomes, Apgar scores and overall maternal satisfaction with analgesia were noted.

RESULTS

The time-weighted hourly consumption of ropivacaine (PCEA and clinician supplementation for breakthrough pain) was significantly lower in the PCEA+AMB group (mean=7.6 mL, SD 3.2) compared to the PCEA+BI group (mean=9.3 mL, SD 2.5; P<0.001). The mean time to first PCEA self-bolus following CSE was significantly longer in the PCEA+AMB group compared to the PCEA+BI group (268 min vs. 104 min; P<0.001). Parturients in Group PCEA+AMB also gave higher satisfaction scores. The incidence of breakthrough pain was similar in both groups.

CONCLUSION

PCEA+AMB, when compared to PCEA+BI, confers greater patient satisfaction and a longer duration of effective analgesia after CSE despite reduced analgesic consumption.

Merlin, a tumor suppressor, interacts with transactivation-responsive RNA-binding protein and inhibits its oncogenic activity

The neurofibromatosis type 2 gene-encoded protein, merlin, is related to the ERM (ezrin, radixin, and moesin) family of membrane-cytoskeleton-associated proteins. Recent studies suggest that the loss of neurofibromatosis type 2 function contributes to tumor development and metastasis. Although the cellular functions of merlin as a tumor suppressor are relatively well characterized, the cellular mechanism whereby merlin controls cell proliferation from membrane locations is still poorly understood. During our efforts to find potential merlin modulators through protein-protein interactions, we identified transactivation-responsive RNA-binding protein (TRBP) as a merlin-binding protein in a yeast two-hybrid screen. The interaction between TRBP and merlin was confirmed by glutathione S-transferase pull-down assays, co-immunoprecipitation, and co-localization experiments. The carboxyl-terminal regions of each protein were responsible for their interaction. Cells overexpressing TRBP showed enhanced cell growth in cell proliferation assays and also exhibited transformed phenotypes, such as anchorage-independent cell growth and tumor development in mouse xenografts. Merlin efficiently inhibited these oncogenic activities of TRBP in our experiments. These results provide the first clue to the functional interaction between TRBP and merlin and suggest a novel mechanism for the tumor suppressor function of merlin both in vitro and in vivo.

The ProSeal™ Laryngeal Mask Airway is an Effective Alternative to Laryngoscope-Guided Tracheal Intubation for Gynaecological Laparoscopy

We tested the hypothesis that the ProSeal™ laryngeal mask airway is superior to laryngoscope-guided tracheal intubation for gynaecological laparoscopy. One-hundred and eighty consecutive patients (ASA grade 1-2, aged 18-80y) were divided into two equal-sized groups for airway management with the ProSeal™ laryngeal mask airway or tracheal tube. Induction was with fentanyl/propofol, maintenance with sevoflurane and muscle relaxation with atracurium. The following primary variables were tested: time to achieve an effective airway, ventilatory capability, peak airway pressure before and after pneumoperitoneum, duration of surgery and pneumoperitoneum and haemodynamic responses. Data about gastric size, airway trauma and sore throat were collected. The number of attempts for successful insertion were similar, but effective airway time was shorter for the ProSeal™ laryngeal mask airway (20±2s vs 37±3s, P<0.001). All devices were successfully inserted within three attempts. There was no episode of failed ventilation or hypoxia. The haemodynamic stress responses to insertion and removal were greater for the tracheal tube than the ProSeal™ laryngeal mask airway. The duration of surgery, duration of pneumoperitoneum and intraabdominal pressures were similar. Gastric size was similar at the start and end of surgery. There were no differences in the frequency of complications or sore throat.

We conclude that the ProSeal™ laryngeal mask airway is a similarly effective airway device to conventional laryngoscope-guided tracheal intubation for gynaecological laparoscopy, but is more rapidly inserted and associated with an attenuated haemodynamic response to insertion and removal.

Video and optic laryngoscopy assisted tracheal intubation--the new era

With advances in technology, videoscopy and optic intubation have been gaining popularity particularly in patients with difficult airways or as rescue devices in failed intubation attempts. Their routine use is, however an uncommon occurrence. This review paper will summarise some of those newly developed devices currently available to assist tracheal intubation, their advantages, disadvantages when compared with the conventional laryngoscope and finally, evidence to support their use in both elective and emergency airway management.

Caspase-2-mediated cell death is required for deleting aneuploid cells

Caspase-2, one of the most evolutionarily conserved of the caspase family, has been implicated in maintenance of chromosomal stability and tumour suppression. Caspase-2 deficient (Casp2^−/−) mice develop normally but show premature ageing-related traits and when challenged by certain stressors, succumb to enhanced tumour development and aneuploidy. To test how caspase-2 protects against chromosomal instability, we utilized an ex vivo system for aneuploidy where primary splenocytes from Casp2^−/− mice were exposed to anti-mitotic drugs and followed up by live cell imaging. Our data show that caspase-2 is required for deleting mitotically aberrant cells. Acute silencing of caspase-2 in cultured human cells recapitulated these results. We further generated Casp2^C320S mutant mice to demonstrate that caspase-2 catalytic activity is essential for its function in limiting aneuploidy. Our results provide direct evidence that the apoptotic activity of caspase-2 is necessary for deleting cells with mitotic aberrations to limit aneuploidy.

Comparative genomic hybridization array analysis and real time PCR reveals genomic alterations in squamous cell carcinomas of the lung

Genomic alterations have been identified in lung cancer tissues and reported in numerous studies. To analyze genomic aberrations in lung cancer patients, we used array comparative genomic hybridization (array CGH) in 14 squamous cell lung carcinoma (SqC) tissues. Copy number gain and loss in chromosomal regions were detected, and the corresponding genes were confirmed by real time PCR. Several frequently altered loci, including gain of 3q (36% of samples), were found. The most frequently identified losses were found at 14q32.33 (21% of samples). The relative degree of chromosomal change was analyzed using log2 ratios. High-level DNA amplifications (>0.8 log2 ratio) were detected at 20 regions in 1p, 2q, 3q, 4q, 6q, 7p, 8q, 9p, 10q, 12q, 14q and 19p. We found that the fold change levels were highest at EVI1 (3q26.2), LPP (3q27-28) and FHF-1 (3q28) gene loci. Our results show that array CGH is a useful tool for identification of gene alteration in lung cancer, and that the above-mentioned genes might represent potential candidate genes for pathogenesis and diagnosis of lung cancer.

Systemic and mucosal immune responses to rhesus rotavirus vaccine MMU 18006

Thirty-four children 3 to 20 months of age ingested either 10(5), 10(4) or 10(3) plaque-forming units of rhesus rotavirus vaccine, MMU 18006, which possesses human rotavirus serotype 3 neutralization antigen. Immune responses were evaluated by a plaque reduction neutralization (PRN) assay to rotavirus serotypes 1, 2 and 3 and by a serum IgG, IgM and IgA and fecal IgA class-specific enzyme-linked immunosorbent assay. Homotypic PRN antibody seroconversions to serotype 3 rotavirus were detected in 31 of 34 children (91%), whereas rises in heterotypic PRN antibody to human rotavirus serotypes 1 or 2 were found in only 3 of 21 (14%) (p less than 0.00000001). Thirty of the 34 vaccinated children (88%) had at least one class of rotavirus-specific serum antibody detected by enzyme-linked immunosorbent assay. A rotavirus-specific IgA coproantibody response was seen in 11 of 16 children (69%) following vaccination. Two children who had no evidence of PRN antibody to serotype 3 after vaccination had evidence of both a fecal and a serum rotavirus-specific IgA response, suggesting that in these children the response to the vaccine was primarily mucosal. These data show that orally administered rhesus rotavirus vaccine MMU 18006 elicits local intestinal immunity but produces primarily a homotypic serum neutralization response as measured by plaque reduction neutralization assays.

KAI1/CD82 suppresses tumor invasion by MMP9 inactivation via TIMP1 up-regulation in the H1299 human lung carcinoma cell line

We conducted a study on the mechanism of KAI1/CD82-mediated suppression of tumor invasiveness and metastasis, and examined its effect on MMP-9 activity and the TIMP1 levels in H1299 human non-small cell lung carcinoma cells. The H1299 human lung carcinoma cells were transfected with pcDNA3.1-CD82 and stable transfectant clones that had a high KAI1/CD82 expression were obtained. We performed Western blot analysis, cell invasion assay, gelatin zymography, and RT-PCR to assess the KAI1/CD82 expression and tumor invasiveness, the MMP-9 activity, the MMP-9 mRNA and protein levels, and the TIMP1 levels in the H1299/CD82 transfectant cells and compared the results with those of the control groups. The H1299/CD82 transfectants exhibited significant suppression of cell invasion, reduced MMP9 enzyme activity, elevated MMP9 mRNA and MMP-9 protein levels, and elevated TIMP1 levels. It may be postulated that KAI1/CD82 over-expression in the H1299 non-small cell lung carcinoma cells suppresses the tumor invasiveness and metastatic potential by inducing MMP9 inactivation via the up-regulation of TIMP1.

PXR, CAR and HNF4alpha genotypes and their association with pharmacokinetics and pharmacodynamics of docetaxel and doxorubicin in Asian patients

Previously studied candidate genes have failed to account for inter-individual variability of docetaxel and doxorubicin disposition and effects. We genotyped the transcriptional regulators of CYP3A and ABCB1 in 101 breast cancer patients from 3 Asian ethnic groups, that is, Chinese, Malays and Indians, in correlation with the pharmacokinetics and pharmacodynamics of docetaxel and doxorubicin. While there was no ethnic difference in docetaxel and doxorubicin pharmacokinetics, ethnic difference in docetaxel- (ANOVA, P=0.001) and doxorubicin-induced (ANOVA, P=0.003) leukocyte suppression was observed, with Chinese and Indians experiencing greater degree of docetaxel-induced myelosuppression than Malays (Bonferroni, P=0.002, P=0.042), and Chinese experiencing greater degree of doxorubicin-induced myelosuppression than Malays and Indians (post hoc Bonferroni, P=0.024 and 0.025). Genotyping revealed both PXR and CAR to be well conserved; only a PXR 5'-untranslated region polymorphism (-24381A>C) and a silent CAR variant (Pro180Pro) were found at allele frequencies of 26 and 53%, respectively. Two non-synonymous variants were identified in HNF4alpha (Met49Val and Thr130Ile) at allele frequencies of 55 and 1%, respectively, with the Met49Val variant associated with slower neutrophil recovery in docetaxel-treated patients (ANOVA, P=0.046). Interactions were observed between HNF4alpha Met49Val and CAR Pro180Pro, with patients who were wild type for both variants experiencing least docetaxel-induced neutropenia (ANOVA, P=0.030). No other significant genotypic associations with pharmacokinetics or pharmacodynamics of either drug were found. The PXR-24381A>C variants were significantly more common in Indians compared to Chinese or Malays (32/18/21%, P=0.035) Inter-individual and inter-ethnic variations of docetaxel and doxorubicin pharmacokinetics or pharmacodynamics exist, but genotypic variability of the transcriptional regulators PAR, CAR and HNF4alpha cannot account for this variability.

The role of nitric oxide in the particulate matter (PM2.5)-induced NFκB activation in lung epithelial cells

NFkappaB is one of key transcription factors that are involved in the inflammatory responses to the particulate matter (PM) in the lungs. In order to further understand the molecular mechanism, the effects of antioxidants and an inducible nitric oxide synthase (iNOS) inhibitor on PM-induced NFkappaB activation were examined in A549 lung epithelial cells. NFkappaB activation by 2.5 microm particulates (PM2.5) was evident from the degradation of an NFkappaB inhibitory protein, IkappaBalpha, and a luciferase reporter assay for NFkappaB activity. In these experiments, a pre-treatment of the cells with antioxidants N-acetyl-l-cysteine (NAC) and dimethylthiourea (DMTU) or an iNOS inhibitor l-N6-1-iminoethyl-lysine (L-NIL) clearly inhibited the NFkappaB activation by PM2.5. The inhibitory effect of L-NIL was also observed on the PM2.5-induced interleukin-8 (IL-8) gene expression both at the transcriptional and protein levels. These results suggest that PM2.5 induces NFkappaB activity via the pathways involving ROS and/or RNS generation. Considering the fact that NFkappaB also induces NO generation via iNOS expression, they might make a positive feedback loop that amplifies the downstream responses.

Merlin Neutralizes the Inhibitory Effect of Mdm2 on p53

The stability of p53 tumor suppressor is regulated by Mdm2 via the ubiquitination and proteasome-mediated proteolysis pathway. The c-Abl and PTEN tumor suppressors are known to stabilize p53 by blocking the Mdm2-mediated p53 degradation. This study investigated the correlation between p53 and merlin, a neurofibromatosis 2 (NF2)-related tumor suppressor, in association with the Mdm2 function. The results showed that merlin increased the p53 stability by inhibiting the Mdm2-mediated degradation of p53, which accompanied the increase in the p53-dependent transcriptional activity. The stabilization of p53 by merlin appeared to be accomplished through Mdm2 degradation, and the N-terminal region of merlin was responsible for this novel activity. This study also showed that overexpression of merlin-induced apoptosis of cells depending preferentially on p53 in response to the serum starvation or a chemotherapeutic agent. These results suggest that merlin could be a positive regulator of p53 in terms of tumor suppressor activity, and provide the promising therapeutic means for treating tumors with non-functional merlin or Mdm2 overexpression.

Intensive breast screening in BRCA2 mutation carriers is associated with reduced breast cancer specific and all cause mortality

Background

The addition of annual MRI screening to mammography has heightened optimism that intensive screening along with improved treatments may substantially improve life expectancy of women at high risk of breast cancer. However, survival data from BRCA2 mutation carriers undergoing intensive combined breast screening are scarce.

Methods

We have collated the results of screening with either annual mammography or mammography with MRI in female BRCA2 mutation carriers in Manchester and Oslo and use a Manchester control group of BRCA2 mutation carriers who had their first breast cancer diagnosed without intensive screening.

Results

Eighty-seven BRCA2 mutation carriers had undergone combined (n = 34) or mammography (n = 53) screening compared to 274 without such intensive screening. Ten year breast cancer specific survival was 100 % in the combined group (95 % CI 82.5–100 %) and 85.5 % (95 % CI 72.6–98.4 %) in the mammography group compared to 74.6 % (95 % CI 66.6–82.6 %) in the control group. Better survival was driven by lymph node status (negative in 67 % of screened vs 39 % of unscreened women; p < 0.001) and a significantly greater proportion of intensively screened women had invasive breast cancers <2 cm at diagnosis (74.6 % vs 50.4 %; p = 0.002).

Conclusion

Intensive combined breast cancer screening with annual MRI and mammography appears to improve survival from breast cancer in BRCA2 mutation carriers. Data from larger groups are required to confirm the effectiveness of combined screening in BRCA2 carriers.

Solution structure of the dimeric cytoplasmic domain of syndecan-4

The syndecans, transmembrane proteoglycans which are involved in the organization of cytoskeleton and/or actin microfilaments, have important roles as cell surface receptors during cell-cell and/or cell-matrix interactions. Since previous studies indicate that the function of the syndecan-4 cytoplasmic domain is dependent on its oligomeric status, the conformation of the syndecan-4 cytoplasmic domain itself is important in the understanding of its biological roles. Gel filtration results show that the syndecan-4 cytoplasmic domain (4L) itself forms a dimer stabilized by ionic interactions between peptides at physiological pH. Commensurately, the NMR structures demonstrate that syndecan-4L is a compact intertwined dimer with a symmetric clamp shape in the central variable V region with a root-mean-square deviation between backbone atom coordinates of 0.95 A for residues Leu(186)-Ala(195). The molecular surface of the 4L dimer is highly positively charged. In addition, no intersubunit NOEs in membrane proximal amino acid resides (C1 region) have been observed, demonstrating that the C1 region is mostly unstructured in the syndecan-4L dimer. Interestingly, two parallel strands of 4L form a cavity in the center of the dimeric twist similar to our previously reported 4V structure. The overall topology of the central variable region within the 4L structure is very similar to that of 4V complexed with the phosphatidylinositol 4,5-bisphosphate; however, the intersubunit interaction mode is affected by the presence of C1 and C2 regions. Therefore, we propose that although the 4V region in the full cytoplasmic domain has a tendency for strong peptide--peptide interaction, it may not be enough to overcome the repulsion of the C1 regions of syndecan-4L.

Comparison of computer integrated patient controlled epidural analgesia vs. conventional patient controlled epidural analgesia for pain relief in labour

Computer integrated-patient controlled epidural analgesia (CI-PCEA) is a novel drug delivery system. It automatically titrates the background infusion rate based on the individual parturient's need. In this randomised trial, we compared the local anaesthetic consumption by parturients using CI-PCEA with demand only patient controlled epidural analgesia (PCEA) for labour analgesia. We recruited 40 parturients after approval by the ethics committee. Group PCEA (n = 20) received demand only PCEA. Group CI-PCEA (n = 20) received a similar PCEA regimen but the computer integration titrated the background infusion to 5, 10 or 15 ml x h(-1) if the patient required one, two or three demand boluses, respectively, in the previous hour. The background infusion decreased by 5 ml x h(-1) if there was no demand bolus in the previous hour. The sample size was calculated to show equivalence in local anaesthetic used. The time weighted consumption of local anaesthetic was similar in both groups (mean difference 0.7 mg x h(-1), 95% confidence interval [CI: -2.5, 1.1]; p = 0.425). The CI-PCEA group had higher maternal satisfaction scores: mean (SD) 93 (7) vs. 86 (11), p = 0.042. CI-PCEA does not increase the use of local anaesthetic when compared with demand only PCEA but does increase patient satisfaction.

Effect of dietary restriction on age-related increase of liver susceptibility to peroxidation in rats

Dietary restriction (DR) increases life span and decreases age-related diseases in experimental animals. It has received a great deal of attention in connection with the relationship between aging, nutrition, and oxidative stress because oxidative injury in several organ systems is a prominent feature in aging. We investigated the possibility that DR can protect vulnerable liver lipids against age-related increases of peroxidation. Male Fischer 344 rats fed ad libitum (AL) or dietarily restricted (maintained on 60% of AL food intake) were killed by decapitation at 4 (young) or 12 mon (adult) of age. Phosphatidylcholine hydroperoxide (PCOOH) concentration of liver was determined using a chemiluminescent high-performance liquid chromatographic method. Liver PCOOH increased with age in adult rats, but less of an increase of PCOOH was seen in DR rats, which is consistent with results on production of thiobarbituric acid-reactive substances and oxygen-derived free radicals. No significant differences were found in liver superoxide dismutase and catalase activity between AL and DR groups of young and adult rats. Liver triglyceride and cholesterol contents were lower in DR than AL rats at 12 mon. Fatty acid compositions of phosphatidylcholine and phosphatidylethanolamine indicated that the ratio of (20:3n-6 + 20:4n-6)/18:2n-6, an index of linoleic acid (18:2n-6) desaturation, was lower in DR than in AL rats. We concluded that DR suppresses age-related oxidative damage in liver by modulating the amount of lipid as well as fatty acid composition.