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.

Processing speed deficits associated with traumatic brain injury: processing inefficiency or cautiousness?

This study used speed-accuracy trade-off (SAT) methodology to test competing explanations for processing speed deficits due to traumatic brain injury (TBI): fixed limited capacity and volition. Twenty TBI participants and 20 comparison participants performed a visual scanning task with processing times controlled by the experimenter using a response deadline procedure. Results of the study demonstrated marked differences in SAT functions between the two groups. Participants who had TBIs were significantly slower on information accrual across processing deadlines (supporting a fixed limit explanation), but when early responding was allowed they chose to hold off responding despite being no more accurate in their responses with the additional time (a finding supporting a volitional explanation). Results of the study are discussed in terms of a resource allocation model that incorporates the influences of both processing capacity and volitional processes for individuals who suffer from brain injuries.

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.

Localization of Accessory Pathways in the Wolff-Parkinson-White Pattern?Physician Versus Computer Interpretation of the Same Algorithm

BACKGROUND

There are several published algorithms for the prediction of accessory pathway (AP) location in the Wolff-Parkinson-White syndrome from the 12-lead electrocardiogram (ECG). Most depend on stepwise criteria, and minor disagreements between observers over QRS transition point or delta wave axis may lead to different classification of pathway location. We compared the utility of a computerized program in identifying pathway location from the ECG using the algorithm published by Fitzpatrick and coworkers(3) against physician assessment with the same algorithm.

METHODS

Thirty-one 12-lead ECGs with an overt preexcitation pattern were examined by three physicians and AP localized to one of eight anatomical sites using the Fitzpatrick algorithm, with disagreements resolved by consensus. Similarly, pathway location was determined by the Glasgow ECG program with the Fitzpatrick algorithm incorporated into its logic.

RESULTS

The agreement between each physician and their consensus was 28/31, 29/31, and 29/31. Similarly, assessment by the Glasgow program produced agreement with the physician consensus in 29/31 cases. Of the 24 patients who underwent radiofrequency ablation, the program localized the pathway to the true or adjacent annular region in 20, compared to 20/24 by physician assessment of the algorithm, producing a similar predictive accuracy to published data.

CONCLUSION

This study has shown that incorporation of the Fitzpatrick algorithm for AP location into a widely used computer program results in the same level of performance as that of experienced physicians and may be useful in clinical practice as an aid to referral for electrophysiological study and ablation.

Evaluation of the electrocardiographic criteria for left ventricular hypertrophy

OBJECTIVE

Left ventricular hypertrophy (LVH) is an independent predictor of cardiovascular (CV) mortality. This study compared different criteria including Sokolow-Lyon and Cornell, in terms of voltage and voltage-QRS-duration products, as well as point-scoring systems such as the Romhilt-Estes, Perugia and Glasgow-Royal-Infirmary modified Romhilt-Estes score.

METHODS

Patients undergoing echocardiography were recruited from the cardiology department in Glasgow Royal Infirmary. Echocardiographically derived left ventricular mass was indexed to body surface area and using sex dependent thresholds, LVH was determined. Electrocardiograms (ECG) were processed using The University of Glasgow Analysis Program, permitting different LVH criteria to be calculated and evaluated. Inclusion criteria for this study were that the patients had a technically adequate echocardiogram and ECG.

RESULTS

The main analysis used 51 male and 76 female patients. At published thresholds, the Lewis index gave the greatest sensitivity of the voltage criteria (12%). However, adjusted to 95% specificity, the Cornell index produced the greatest sensitivity at 19%. The best voltage-duration product was the Cornell product that gave 15% sensitivity and 19% when adjusted to 95% specificity. The point scoring systems proved to be the most accurate with the Perugia score being 22% sensitive and the Glasgow Royal Infirmary modified Romhilt-Estes score 24 % sensitive, both at 95% specificity.

CONCLUSION

This study finds that ECG criteria for LVH that use only voltage are relatively poor predictors of LVH. This study also finds that the best criteria for assessing LVH are the point scoring criteria, in particular the Glasgow Royal Infirmary Modified Romhilt-Estes score.

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.