Ink dispersion by sequential contractions in isolated segments of guinea pig ileum and duodenum

Conventional preparations that record the effect of contractions on intestinal flow assess primarily net propulsion and not flow events that like mixing are essential for digestion and absorption. Here we recorded the flow of an ink bolus in response to peristaltic contractions of segments of guinea pig intestine. It took three to four contraction/relaxation cycles to disperse a tiny and compact ink bolus throughout the intestinal segment. This was achieved by stretching, propulsion and separation of the bolus into portions during the contraction phase, and return and confluence of the bolus portions during the relaxation phase. As the contraction advanced through the intestinal segment, it generated rapid retrograde flow through its narrow lumen; eddies (flow vortices) formed at upstream shoulder of the contracting segment and dispersed the ink radially. The contraction cleared much of the fluid from the intestinal segment; during the subsequent relaxation, fluid returned into the segment, and carried portions of the ink upstream into the segment where it coalesced with residual portions. The current video observations of luminal flow confirm earlier predictions on luminal flow derived from computations. These flow events are likely an important mechanism through which intestinal contractions promote digestion and absorption.

Risk profiles for non-adherence to antipsychotic medications

Poor adherence to medications is common in individuals with schizophrenia, and can lead to relapse and re-hospitalization. This paper presents the findings of an Australian study of the factors affecting antipsychotic medication taking in individuals with schizophrenia. The Factors Influencing Neuroleptic Medication Taking Scale was used with a non-probability sample of mental health service users. Ethics approval was obtained from a university and a hospital ethics committee. Data were analysed using spss version 15. Most participants had insight into their illness and were aware of the stigma of mental illness. Around 70% experienced annoying side effects, while nearly half admitted alcohol consumption. About one-fifth admitted they had missed taking medications during the previous week. Significant others played a variable role in medication taking. Over 80% were satisfied with their relationships with health professionals, but were less satisfied with access to these professionals, especially psychiatrists. Logistic regression analysis showed that age, impact of medication side effects, and access to psychiatrists were independent predictors of medication omission. It is argued that medication taking is a complex issue, which needs to be taken into consideration in health professional training and measures to promote adherence.

Mental health professionals' attitudes towards consumer participation in inpatient units

Consumer participation has been a major focus in mental health services in recent years, but the attitudes of mental health professionals towards this initiative remain variable. The purpose of this study was to describe mental health professionals' attitudes towards mental health consumer participation in inpatient psychiatric units. The Consumer Participation and Consultant Questionnaire was used with a non-probability sample of 47 mental health professionals from two adult inpatient psychiatric units situated in a large Australian public general hospital. Ethics approval was obtained from a university and a hospital ethics committee. Data were analysed using SPSS, Version 12. Overall, respondents had favourable attitudes towards consumer participation in management, care and treatment, and mental health planning. They were less supportive about matters that directly or indirectly related to their spheres of responsibility. The type of unit that the respondents worked in was not a factor in their beliefs about consumer participation. Recommendations are made about the development of guidelines for consumer participation in inpatient units, the educational preparation of mental health clinicians, and the need for mental health professionals to reflect on, and discuss their own beliefs and practices about, consumer participation.

A phase II placebo-controlled trial of neoadjuvant anastrozole alone or with gefitinib in early breast cancer

PURPOSE

Increased epidermal growth factor receptor (EGFR) expression may promote breast cancer resistance to endocrine therapy. We have therefore investigated whether neoadjuvant gefitinib, an EGFR inhibitor, might overcome biologic and clinical resistance to neoadjuvant anastrozole in a phase II placebo-controlled trial.

PATIENTS AND METHODS

Postmenopausal women with stage I to IIIB hormone receptor-positive early breast cancer received anastrozole 1 mg daily for 16 weeks and were randomly assigned at a ratio of 2:5:5 to receive, in addition, gefitinib 250 mg/d orally for 16 weeks: placebo 1 tablet/d orally for 2 weeks and then gefitinib for 14 weeks or placebo for 16 weeks. The primary end point was biologic change in proliferation as measured by Ki67 at 2 and 16 weeks; the main secondary end point was overall objective response (OR).

RESULTS

Two hundred six women were randomly assigned. Mean changes in Ki67 with anastrozole and gefitinib versus anastrozole alone were -77.4% and -83.6%, respectively, between baseline and 16 weeks (geometric mean ratio = 1.37; 95% CI, 0.79 to 2.39; P = .26), -80.1% and -71.3% between baseline and 2 weeks (geometric mean ratio = 0.70; 95% CI, 0.39 to 1.25; P = .22) and -19.3% and -43% (geometric mean ratio = 1.42; 95% CI, 0.86 to 2.35; P = .16) between 2 and 16 weeks. ORs in the combination and anastrozole alone groups were 48% and 61% (estimated difference = -13.1%; 95% CI, -27.3% to 1.2%), respectively, with a nonsignificant trend against the combination (P = .08) and 48% versus 72% (estimated difference = -24.1%; 95% CI, -45.3% to -2.9%) in the progesterone-receptor-positive subgroup, which was significant (P = .03) and consistent with Ki67 changes. Common treatment-related adverse events included diarrhea, rash, alopecia, dry skin, and nausea. There was no evidence of a pharmacokinetic interaction.

CONCLUSION

Addition of gefitinib to neoadjuvant anastrozole had no additional clinical or biologic effect, failing to support our original hypothesis.

Identification of predictive markers to differentiate ixabepilone from paclitaxel activity in ER-negative breast cancer patients

2525

Background: Ixabepilone (BMS-247550) is a microtubule stabilizing agent with demonstrable therapeutic value in taxane- refractory breast cancer (BC) patients. Biomarkers to predict either ixabepilone or paclitaxel activity in BC patients have previously been reported. However, markers that differentiate response to the two agents have yet to be identified. This study sought to discover predictive markers that will enable patient selection to differentially enhance response to ixabepilone or paclitaxel in ER-negative (ER-) patients. Materials and Methodologies: Pre-treatment gene expression profiles were generated for 62 ER- patients treated with ixabepilone in clinical study CA163080, and 51 ER- patients treated with T/FAC (paclitaxel and fluorouracil-doxorubicin-cyclophosphamide) in clinical study MDA133. Biomarkers differentially predictive of complete pathological response in breast were identified through gene set enrichment analysis (GSEA) or classification by threshold gradient descent (TGD). Gene knockdown by siRNA was used to study some of these candidate markers. Results: Four candidate models that differentiate response to ixabepilone treatment and taxane-containing therapy were identified. Two of the models, found by GSEA, are based on expression levels for single microtubule-related genes: transforming, acidic coiled-coil containing protein 3 (TACC3) and chromosome condensation protein G (HCAP-G). The potential of HCAP-G as a differential marker was supported by siRNA studies. Two of the models, found by TGD, are based on expression levels for 26 and 20 genes. Areas under the ROC curves for the models applied to each study separately are given in the table . Conclusions: We have identified four predictive models that differentiate response in a clinical trial of ixabepilone from that in a trial of T/FAC. A clinical trial is under way to further evaluate their utility for differentiating response to ixabepilone- and taxane-containing regimens.

[Table: see text]

[Table: see text]

Identification of sensitivity markers for BMS-536924, an inhibitor for insulin-like growth factor-1 receptor

3506

Background: Insulin-like growth factor-1 receptor (IGF-1R) signaling is an important regulator of mitogenesis, transformation to the oncogenic phenotype and anti-apoptotic effects in malignant cells. Over-expression of IGF-1R, seen in many tumors, may confer a growth advantage or drug resistance. A potent small-molecule inhibitor (BMS-536924) of IGF-1R tyrosine kinase showed anti-tumor activity in sarcoma, prostate, colon and pancreatic tumor models. One of the integral goals in the development of BMS-536924 as a cancer therapeutic is to identify molecular biomarkers predictive of response to the drug that ultimately will aid in selecting the patients who are most likely to benefit. Methods: The sensitivity (IC50) to BMS-536924 was determined for a panel of 29 pediatric sarcoma and neuroblastoma cell lines. Both microarray and LC/MS based protein profiling were utilized to analyze the baseline gene or protein expression level. Drug treatment studies were performed using two rhabdomyosarcoma cell lines, Rh41 (sensitive to BMS-536924) and Rh36 (resistant to the drug) to identify markers that are modulated by BMS-536924. Results: (1). Sixteen out of the 29 cell lines were highly sensitive to BMS-536924; candidate markers that correlated with the sensitivity to BMS-536924 were identified by gene expression and protein profiling. (2). Histological correlation was also discovered, with specific subtypes of sarcoma having a low IC50 to BMS-536924. (3). Pathway analysis noted that some major candidate markers are common key steps in the EGF-R pathway and the IGF1-R pathway. This observation of cross-talk between the two pathways led to the hypothesis of synergy with combined inhibition of both pathways. Combination studies of BMS-536924 and EGFR inhibitors were performed and synergism was observed. (4). Markers modulated by BMS-536924 in a sensitive cell line were identified. Conclusions: This work has identified candidate markers correlating to BMS-536924 sensitivity in vitro. The possible mechanism of synergistic activity of IGF1-R and EGFR inhibitors will be presented.

No significant financial relationships to disclose.

Identification of predictive and surrogate molecular markers for dasatinib in prostate cancer: Rationale for patient selection and efficacy monitoring

3579

Background: Dasatinib is a potent, multi-targeted kinase inhibitor that was recently approved for treatment of chronic myelogenous leukemia resistant to imatinib. To aid its clinical development in prostate cancer, we used a panel of prostate cancer cell lines to identify molecular markers that could be used to predict sensitivity to dasatinib and to monitor its activity. Methods: Baseline gene expression profiles of 16 cell lines were used to identify predictive biomarkers based on the correlation of gene expression with in vitro sensitivity of cells to dasatinib. Selected cell lines were treated with dasatinib to identify surrogate biomarkers based upon changes in gene expression following dasatinib treatment. Results: We identified 174 genes whose baseline expression levels were highly correlated with sensitivity or resistance to dasatinib. These include cell lineage markers cytokeratin 5 (CK5), androgen receptor (AR), and prostate specific antigen (PSA). Our results indicate that “basal type” cell lines (those with high expression of CK5 and low expression of AR and PSA) are sensitive to dasatinib. Dasatinib treatment studies further identified genes whose expression levels were significantly modulated by the drug. Ten genes, including urokinase-type plasminogen activator (uPA), were not only significantly correlated with sensitivity to dasatinib but also reduced in their expression upon drug treatment. In addition, the down-regulation of uPA was specific to dasatinib and the effect was not seen in taxol-treated cells. The extent of down-regulation was correlated with the sensitivity of cell lines to dasatinib. EphA2, a specific kinase target of dasatinib, was identified as a biomarker common to prostate and breast cancers. Finally, the expression of 5 genes including CK5, AR, PSA, uPA and EphA2 in prostate tumors was examined and the dasatinib sensitivity signature was validated using a published data set derived from a clinical population. Conclusions: Candidate markers correlated with dasatinib sensitivity were identified. A five-gene model consisting of predictive markers as well as potential surrogate markers has been formulated and will be evaluated in ongoing dasatinib prostate cancer trials.

No significant financial relationships to disclose.

Electrical activity during the 2006 Mount St. Augustine volcanic eruptions

By using a combination of radio frequency time-of-arrival and interferometer measurements, we observed a sequence of lightning and electrical activity during one of Mount St. Augustine's eruptions. The observations indicate that the electrical activity had two modes or phases. First, there was an explosive phase in which the ejecta from the explosion appeared to be highly charged upon exiting the volcano, resulting in numerous apparently disorganized discharges and some simple lightning. The net charge exiting the volcano appears to have been positive. The second phase, which followed the most energetic explosion, produced conventional-type discharges that occurred within plume. Although the plume cloud was undoubtedly charged as a result of the explosion itself, the fact that the lightning onset was delayed and continued after and well downwind of the eruption indicates that in situ charging of some kind was occurring, presumably similar in some respects to that which occurs in normal thunderstorms.

Perioperative transfusion for pancreaticoduodenectomy and its impact on prognosis in resected pancreatic ductal adenocarcinoma

BACKGROUND AND AIMS

Pancreaticoduodenectomy (PD) is a major operative intervention performed most commonly for malignancy in the head of pancreas. The aim of this study was to evaluate the utilization of blood transfusion for PD and to determine whether this had prognostic significance in a subset of patients with pancreatic ductal adenocarcinoma (PDAC).

MATERIAL AND METHODS

Data on blood transfusion requirement were retrospectively collected for patients undergoing PD from 1998 to 2005. Standard prognostic factors and survival data were also collected in patients with PDAC.

RESULTS

One-hundred-and-seventy patients underwent PD. Seventy-six patients (45%) received transfusion. The median (interquartile range) number of units of red cell concentrate (RCC) transfused perioperatively (intraoperatively and within 24 h of surgery) was 1.5 (0.5-2.5). The median preoperative haemoglobin (Hb) was 126 g/dl. The median number of units of RCC transfused perioperatively in patients with Hb <126 g/dl was 2 (1-3); for those with Hb > or = 126 g/dl the median was 0 (0-1); p=0.003. Forty-nine patients who were resected for PDAC were subjected to survival analysis. Univariate and multivariate analyses showed that only posterior resection margin invasion was associated with an adverse outcome (margin positive 198 [143-470] days vs margin negative 398 [303-859] days; p=0.02). Perioperative RCC transfusion requirement was not a significant predictor of survival (transfusion 408 [214-769] days vs no transfusion 331 [217-391] days; p=0.18). Furthermore, RCC transfusion within 30 days of operation was not a significant predictor of poor survival (transfusion 331 [201-459] days vs no transfusion 317 [196-769] days; p=0.43).

CONCLUSIONS

PD can be performed with a moderately low requirement for RCC transfusion; however, low preoperative haemoglobin is a predictor for the requirement of RCC transfusion. Administration of RCC transfusion does not appear to be a significant adverse prognostic factor in patients with resected PDAC.

Predictive biomarker discovery and validation for the targeted chemotherapeutic ixabepilone

3011

Background: Ixabepilone is a microtubule stabilizing agent with significant therapeutic value in breast cancer (BC) patients. To identify predictive biomarkers capable of identifying patients likely to receive optimal benefit from ixabepilone treatment, preclinical and clinical studies were carried out. Several biomarkers discovered using preclinical models were validated in a neoadjuvant BC clinical study ( CA163080 ) and one, estrogen receptor 1 (ER), was shown to double the pathological complete response (pCR) rate in patients treated with ixabepilone. To identify candidate sets of biomarkers that could further increase the pCR rate we have performed post-hoc analyses of the preclinical and clinical data. Methods: Eighteen BC cell lines were classified as sensitive or resistant (S/R) based on the IC50 values for ixabepilone treatment. Gene expression profiling of the BC cell lines was conducted and genes correlated with the S/R classification were identified using a k-Nearest Neighbors algorithm. Patients in clinical study CA163080 underwent a pretreatment core needle biopsy from which RNA was isolated and gene expression profiles generated (data available on 134 patients). Analyses using the preclinical and clinical markers were conducted using various statistical tools. Results: Several markers used in combination with ER were found to be capable of tripling the pCR to ixabepilone in CA163080. In addition to ER other predictive markers were identified that were as predictive as ER, including several genes whose expression is anti-correlated with ER and are part of the ER pathway. Finally, various sub-group analyses were performed and manifested the importance of clinical sample variation that needs to be considered for the analysis. Conclusions: Several single biomarkers identified from preclinical studies were validated in the clinical study CA163080 , demonstrating the utility of this approach. Such markers can be used in combination to better identify patients likely to respond to ixabepilone in future clinical trials. Furthermore, molecular response markers that can be tied to the mechanism of drug resistance can be used for further developing chemotherapy in drug development.

[Table: see text]

The social patterning of fat and lean mass in a contemporary cohort of children

Studies of the social patterning of obesity in children using body mass index have reported inconsistent results. We explored the association of social class with fat mass and lean mass in a contemporary cohort of children measured using dual energy X-ray absorptiometry. We observed a clear social gradient of fat mass (with children of higher social class having a lower fat mass), but no gradient in lean mass or trunk fat mass. Our data show that inequalities in adiposity are present in primary school children and suggest that social inequalities in childhood obesity may have been underestimated in previous studies.

Microtubule Associated Protein (MAP)-Tau: a novel mediator of paclitaxel sensitivity in vitro and in vivo

Microtubule binding protein Tau was recently identified through gene expression analysis of human breast cancer tissues as a novel marker of response to paclitaxel. This article reviews these recent findings and provides additional information to support the role of Tau as an emerging marker and mediator of paclitaxel sensitivity. Low expression of Tau is associated with increased sensitivity to paclitaxel in human breast cancer as well as in a broad range of cell lines. Down regulation of Tau in cell lines by siRNA increases their sensitivity to paclitaxel but not to anthracycline chemotherapy. We propose that this is due to increased paclitaxel binding to microtubules when microtubules are assembled in the presence of low concentrations (or absence) of Tau compared to microtubules that are formed in the presence of physiological (or higher) levels of Tau.

Low-skill fibreoptic intubation: use of the Aintree Catheter with the classic LMA

We describe a series of patients in whom anaesthetists - many of whom were trainees and had no prior experience of using the Aintree Intubation Catheter - successfully intubated the tracheas of patients in whom conventional attempts at intubation had failed. This was achieved by passing a fibrescope loaded with an Aintree Intubation Catheter through a classic Laryngeal Mask Airway (cLMA), which had already been placed to maintain the patient's airway.

Gene expression profiles predict complete pathologic response to neoadjuvant paclitaxel and fluorouracil, doxorubicin, and cyclophosphamide chemotherapy in breast cancer

PURPOSE

The goal of this study was to examine the feasibility of developing a multigene predictor of pathologic complete response (pCR) to sequential weekly paclitaxel and fluorouracil + doxorubicin + cyclophosphamide (T/FAC) neoadjuvant chemotherapy regimen for breast cancer.

PATIENTS AND METHODS

All patients underwent one-time pretreatment fine-needle aspiration to obtain RNA from the cancer for transcriptional profiling using cDNA arrays containing 30721 human sequence clones. Analysis was performed after profiling, and 42 patients' clinical results were available, 24 of which were used for predictive marker discovery; 18 patients' results were used as an independent validation set.

RESULTS

Thirty-one percent of patients had pCR (six discovery and seven validation), defined as disappearance of all invasive cancer in the breast after completion of chemotherapy. We could identify no single marker that was sufficiently associated with pCR to be used as an individual predictor. A multigene model with 74 markers (P <or=.09) was built using data from the discovery samples and tested on the validation samples. Overall, a 78% (14 of 18) predictive accuracy was observed, with a 100% (three of three) positive predictive value for pCR, a 73% (11 of 15) negative predictive value, a sensitivity of 43% (three of seven), and a specificity of 100% (11 of 11). The expected response rate to T/FAC neoadjuvant therapy in unselected patients is 28%.

CONCLUSION

Our results suggest that transcriptional profiling has the potential to identify a gene expression pattern in breast cancer that may lead to clinically useful predictors of pCR to T/FAC neoadjuvant therapy.

Porcine circovirus-2 and concurrent infections in the field

Porcine circovirus-2 (PCV-2) is the necessary cause of post-weaning multisystemic wasting syndrome (PMWS) in swine; however, a variety of co-factors, including other infectious agents, are thought to be necessary in the full expression of disease. Porcine parvovirus (PPV) was found in the inoculum used in the first experiments to reproduce PMWS in gnotobiotic swine. Retrospective and prospective studies in the field and laboratory have demonstrated PCV-2 can act synergistically with PPV to enhance the severity of PMWS. PCV-2 has been shown to play a role in the porcine infectious disease complex (PRDC). Other co-infecting agents with PCV-2 in the lung include, porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus (SIV) and Mycoplasma hyopneumoniae. Exposure of pregnant sows to PPV, PRRSV, or encephalomyocarditis virus may interact with PCV-2 infected foetuses. The severity of hepatic lesions in PCV-2 infected pigs may be enhanced by co-infection with agents such as swine hepatitis E virus and Aujezsky's disease virus. Additional studies are required to determine the mechanistic basis for the interaction of PCV-2 with other agents in the pathogenesis of the various clinical syndromes that have been associated with PCV-2 infection.