Two-sample Wilcoxon Rank-sum Test Research Articles

A model of cardiopulmonary bypass staged training integrating technical and non-technical skills dedicated to cardiac trainees.

To develop a standardized simulation-based curriculum to teach medical knowledge and technical, communication and critical thinking skills necessary to initiate and wean from cardiopulmonary bypass (CPB) to junior cardiac trainees (CTs) in France. Performance on post-curricular tests was compared between CTs who participated in the new curriculum to those who did not. The simulation-based curriculum was developed by content and education experts. Simulations sequentially taught the skills necessary for initiating and weaning from CPB as well as managing crises by adding fidelity and complexity to scenarios. Nine CTs were randomly assigned to the new curriculum (n=5) or the traditional curriculum (n=4). Skills were assessed using tests of medical knowledge and technical, communication (GRS) and critical thinking (SCT) skills. A two-sample Wilcoxon rank-sum test compared average scores between the two groups. Alpha of 0.05 was set to indicate statistically significant differences. The resutls revealed that CTs in the new curriculum significantly outperformed CTs in the traditional curriculum on technical (18.2 vs 14.8, p=0.05) and communication (3.5 vs 2.2, p=0.013) skills. There was no significant difference between CTs in the new curriculum in the Script Concordance Test (16.5 vs 14.8, p=0.141) and knowledge tests (26.9 vs 24.6, p=0.14) compared to CTs in the traditional curriculum. Our new curriculum teaches communication and technical skills necessary for CPB. The results of this pilot study are encouraging and relevant. They give grounds for future research with a larger panel of trainees. Based on the current distribution of scores, a sample size of 12 CTs per group should yield significant results for all tests.

Serum Interleukin-6 as a Marker of Periprosthetic Shoulder Infection

Infection after shoulder arthroplasty can be a devastating complication, and subacute and chronic low-grade infections have proven difficult to diagnose. Serum marker analyses commonly used to diagnose periprosthetic infection are often inconclusive. The purpose of this study was to evaluate the effectiveness of serum interleukin-6 (IL-6) as a marker of periprosthetic shoulder infection. A prospective cohort study of thirty-four patients who had previously undergone shoulder arthroplasty and required revision surgery was conducted. The serum levels of IL-6 and C-reactive protein (CRP), the erythrocyte sedimentation rate (ESR), and the white blood-cell count (WBC) were measured. The definitive diagnosis of an infection was determined by growth of bacteria on culture of intraoperative specimens. Two-sample Wilcoxon rank-sum (Mann-Whitney) tests were used to determine the presence of a significant difference in the ESR and WBC between patients with and those without infection, while the Fisher exact test was used to assess differences in IL-6 and CRP levels between those groups. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of each marker were also calculated. There was no significant difference in the IL-6 level, WBC, ESR, or CRP level between patients with and those without infection. With a normal serum IL-6 level defined as <10 pg/mL, this test had a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 0.14, 0.95, 0.67, 0.61, and 0.62, respectively. IL-6 analysis may have utility as a confirmatory test but is not an effective screening tool for periprosthetic shoulder infection. This finding is in contrast to the observation, in previous studies, that IL-6 is more sensitive than traditional serum markers for periprosthetic infection.

Abstract OT3-3-01: A multicenter phase II study of docosahexaenoic acid (DHA) in triple negative breast cancer (TNBC) survivors

Abstract Background: The development of effective chemopreventive strategies to reduce the risk of TNBC, is a critical unmet need. Obesity is associated with a chronic inflammatory condition in the white adipose tissue of the breast, characterized microscopically by crown-like structures of the breast (CLS-B). The presence and extent of these lesions is associated with a series of proinflammatory mediators, including tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β) and aromatase. Importantly these proinflammatory mediators are known to be involved in breast carcinogenesis. In translational studies to date, the strongest correlations have been seen between CLS-B and TNF-α. Therefore, we aim to evaluate whether treatment with a dietary supplement, DHA, an omega-3 fatty acid, with potent effects on TNF-α, can decrease obesity-related breast inflammation in women. Trial design: This is a randomized phase II placebo-controlled, double-blinded study of DHA in overweight/obese patients (pts), defined as body mass index (BMI) ≥25 with a history of TNBC. Pts will receive DHA or placebo twice daily for 24 weeks and will undergo core biopsies from normal (non-irradiated contralateral) breast tissue before and after the treatment to determine whether DHA can decrease obesity-related breast inflammation. Eligibility: Inclusion criteria: 1) Age ≥ 18. 2) BMI ≥ 25. 3) Completed treatment for stage I-III TNBC ≥ 6 months prior. 4) No clinical evidence of disease. 5) Adequate accessible breast tissue for pre- and post- treatment biopsy, consisting of one breast unaffected by invasive cancer, which has not been radiated or surgically augmented. 6) Adequate organ and bone marrow function. 7) ECOG status ≤2. Exclusion criteria: 1) DHA supplementation. 2) Aspirin/NSAID use in the month preceding and during the trial. 3) Therapeutic anticoagulation. 4) Regular use of statins, steroids, or immunomodulators. Specific aims: The primary objective is to determine whether treatment with DHA for 24 weeks at 1,000 mg twice daily as compared to placebo reduces normal breast tissue levels of TNF-α in overweight/obese pts with a history of TNBC. The secondary objective is to evaluate the effect of DHA on the change from baseline in levels of the following tissue biomarkers: COX-2, IL-1β, aromatase, and CLS-B. Exploratory endpoints include assessment of age as a predictor of CLS-B and inflammatory biomarkers and the evaluation of red blood cell fatty acid levels as a surrogate of DHA compliance. Statistical methods: Percent change in TNF-α mRNA levels in normal breast tissue between DHA and placebo arm will be compared using two-sample t-test. If normality assumptions are violated, a two-sample Wilcoxon rank-sum test will be used. With 30 subjects in each arm, we will have 80% power to detect effect size as small as 0.74 at 0.05 significance level using a two-sided, two-sample, Student t-test. Accrual: A total of 60 evaluable pts will be enrolled. Assuming a 10% dropout rate and 10% non-evaluable rate, up to 76 participants will be randomized in this study. This trial is currently enrolling pts. Contact information: For more information on this trial, please visit clinicaltrials.gov (NCT01849250) or contact Ayca Gucalp MD (gucalpa@mskcc.org). Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT3-3-01.

Leishmaniasis Direct Agglutination Test: Using Pictorials as Training Materials to Reduce Inter-Reader Variability and Improve Accuracy

BackgroundThe Direct Agglutination Test (DAT) has a high diagnostic accuracy and remains, in some geographical areas, part of the diagnostic algorithm for Visceral Leishmaniasis (VL). However, subjective interpretation of results introduces potential for inter-reader variation. We report an assessment of inter-laboratory agreement and propose a pictorial-based approach to standardize reading of the DAT.MethodologyIn preparation for a comparative evaluation of immunochromatographic diagnostics for VL, a proficiency panel of 15 well-characterized sera, DAT-antigen from a single batch and common protocol was sent to nine laboratories in Latin-America, East-Africa and Asia. Agreement (i.e., equal titre or within 1 titer) with the reading by the reference laboratory was computed. Due to significant inter-laboratory disagreement on-site refresher training was provided to all technicians performing DAT. Photos of training plates were made, and end-titres agreed upon by experienced users of DAT within the Visceral-Leishmaniasis Laboratory-Network (VL-LN).ResultsPre-training, concordance in DAT results with reference laboratories was only 50%, although agreement on negative sera was high (94%). After refresher training concordance increased to 84%; agreement on negative controls increased to 98%. Variance in readings significantly decreased after training from 3.3 titres to an average of 1.0 titre (two-sample Wilcoxon rank-sum (Mann-Whitney) test (z = −3,624 and p = 0.0003)).ConclusionThe most probable explanation for disagreement was subjective endpoint reading. Using pictorials as training materials may be a useful tool to reduce disparity in results and promote more standardized reading of DAT, without compromising diagnostic sensitivity.

99Tcm-EHIDA hepatobiliary imaging for neonatal intrahepatic cholestasis caused by citrin deficiency

Objective To evaluate the imaging characteristics of 99Tcm-EHIDA hepatobiliary scintigraphy in neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD).Methods 99Tcm-EHIDA hepatobiliary scan was performed on 12 NICCD infants (aged (127 ±27) d) and 5 infants as a control group (including 4 cases with hepatitis syndrome and 1 with abnormal lipid metabolism,aged (164 ± 15) d).The differences of hepatic activity retention time and bowel activity visualization time bctwccn the two groups were observed.The two-sample Wilcoxon rank sum test was used to analyze the data.Results In the NICCD group,both hepatic activity retention time and bowel activity visualization time were 180-1440 min (median =360 min).In the control group,hepatic activity retention time and bowel activity visualization time were 60-180 min (median =60 min) and 15-30 min (median =15 min),respectively.The differences of hepatic activity retention time and bowel activity visualization time between the two groups were statistically significant (Z =-3.20 and-3.17,both P ＜ 0.05).Three NICCD infants showed minimal hepatic uptake of the tracer.The bowel activity was not visible in 1 NICCD case.The hepatic uptake and biliary excretion function of this infant were significantly improved on hepatobiliary scintigraphy after treatment,with a bowel activity visualization time of 15 min.Conclusion NICCD infants show impaired hepatic uptake and biliary excretion function on 99Tcm-EHIDA hepatobiliary imaging,which may be used in NICCD diagnosis and treatment response evaluation. Key words: Cholestasis,intrahepatic; Infant,newborn; Radionuclide imaging; Technetium; EHIDA

A randomized open label clinical trial of fixed vs.titrated dose letrozole for ovarian stimulation in breast cancer patients: an interim analysis

Chemotherapy has detrimental effects on ovarian function and future fertility. Ovarian stimulation for oocyte cryopreservation results in supra-physiologic estrogen levels which concerns patients with hormonally sensitive disease. Prospective, randomized, open label, clinical trial of fixed v. titrated dose letrozole with cryopreservation of oocytes and embryos in breast cancer patients. Interim analysis is presented. Patients were randomized by age to one of 2 treatment arms: Fixed dose letrozole with ovarian stimulation starting on day 3 or ovarian stimulation with letrozole initiated and titrated based on estradiol level. Primary outcome was number of mature oocytes and secondary outcomes are shown below. Comparison between groups was performed by the two-sample t-test, Wilcoxon rank-sum or Fisher's exact test as appropriate. Results are shown in Table 1.Tabled 1Interim analysisFixed Letrozole (n=10)Titrated Letrozole (n=10)P-valueAge34±2.534±5.20.96BMI21.9±2.821.5±1.80.70D3 FSH5.9±1.66.4±2.00.57AMH2.3±1.11.8±1.60.47Total gonadotropin dose2463.0±1528.72625.0±1168.30.79Days of stimulation10.6±2.69.3 ±1.30.18Peak estradiol670.1±188.7662.3±262.20.94Estradiol post HCG1072.6±409.61001.6±422.80.71Ooctyes harvested20.5±8.617.0±12.90.49Oocytes mature19.0±8.2 (median=20)13.6±10.7 (median=11.0)0.12Adverse events2 (20%): abdominal pain, OHSS3 (30%): abdominal pain, OHSS, epigastric pain1.00Results reported as mean±standard deviation or frequency (percent). Open table in a new tab Results reported as mean±standard deviation or frequency (percent). Both fixed or titrated letrozole protocols offer similar efficacy with regard to number of oocytes retrieved for cryopreservation in cancer patients pre-chemotherapy. Safety profiles are comparable between arms and consistent with typical IVF regimens. There have been no breast cancer recurrences noted for the first 11 subjects with 1-year follow-up.

Sacral Mesh Pullout Strength Based on Suture Location for Sacrocolpopexy

Background: We sought to compare the pullout strengths of the sacral end of the sacrocolpopexy mesh when attached using one suture at the first versus second sacral vertebral level (S1 vs. S2) in female cadaveric pelvises. Methods: The sacral vertebrae were isolated in 9 unembalmed female cadavers, and segments of polypropylene mesh were attached to the sacrum using stitches at either the S1 or S2 level. The free end of the mesh was pulled at a constant rate. Maximum tension prior to system failure was recorded for each specimen. Suture pullout strengths between the two groups were compared using the two-sample Wilcoxon rank-sum test. Results: In all but one specimen, failure of the system occurred at the point of suture attachment to the anterior longitudinal ligament. Among the nine specimens, median pullout strengths were 7.49 lb (interquartile range 7.95) at S1 and 3.15 lb (interquartile range 2.975) at S2 (p = 0.028). Conclusion: The pullout strength of sutures used to attach the sacrocolpopexy mesh to the sacrum is significantly higher at the S1 level than at the S2 level.

Perioperative Core Body Temperatures Effect on Outcome after Colorectal Resections

The World Health Organization has set a standard of maintaining a core body temperature above 36°C in the perioperative period. The purpose of this study was to examine the relationship between both intraoperative temperature (IOT) and immediate postop core body temperature as it relates to postop complications. A retrospective analysis of a prospective database of patients who underwent an elective segmental colectomy without a stoma, for 3 diagnoses was performed. Six postoperative outcomes were examined: length of stay (LOS), placement of a nasogastric tube, return to the operating room, placement of an interventional drain, diagnosed leak, and surgical site infection (SSI). Statistics were calculated using a two-sample Wilcoxon rank-sum (Mann-Whitney) test. Seventy-nine patients met the inclusion criteria and there were no preoperative differences between the groups (those with a postop complication vs without). LOS > 9 days (36.64°C vs 35.98°C; P = 0.011) and clinical leak (37.06°C vs 35.99°C; P = 0.005) both had a statistically higher average IOT than those who did not. Patients with SSI trended to a higher IOT (36.44°C vs 35.99°C; P = 0.062). When the last IOT recorded was compared with the six outcomes, again length of stay and leak both were statistically significant (P = 0.018, P = 0.012) showing a higher temperature related to a higher complication rate. No other complications were related to IOT, nor did postop temperature relate to complication. In our data, relatively lower IOTs were protective for LOS and clinical leaks, with a trend of lower SSI rates. Further research is needed to fully endorse or refute the absolute recommendations for core body temperature.

Mobile phone short messaging service for optimizing asthma treatment has no healthcare related effects: A controlled trial

Context: One important aspect of modern asthma care is self-management: Allowing the patients to monitor their disease severity continuously and to adjust the dose of inhaled corticosteroid based on the symptoms, lung function, and the use of rescue medication. The Short Messaging Service (SMS) is a convenient, reliable, affordable, and secure means of telemedicine that may improve asthma control. Aim: The objective of this study is to assess the health-related effects of an SMS compliance and monitoring system for optimized asthma treatment. Settings and Design: In total, 244 asthmatics participated in a prospective controlled randomized trial (114 interventions, 130 controls). Materials and Methods: The intervention consisted of sequences of SMS messages sent to the intervention group, each containing two or three monitoring questions and one reminder to take the preventive medication. Both the intervention and control groups received questionnaires on days 0, 45, and 90. The primary outcome measures were a self-assessed outcome questionnaire that included a five question asthma control test, EQ-5D, use of health services, and questions on the use of preventive medicine. Statistical Analysis Used: The Pearson Chi-Square test was used for categorical variables (or Fisher's Exact Test, if the expected count was less than five in one or more cells) and the two-sample t-test or Wilcoxon Rank Sum test was used for continuous variables, as appropriate. The distributional assumption was investigated using histograms and P-P plots. Results: The use of SMS monitoring yielded no health-related effects, no decrease in the use of healthcare services, and no change in the use of medicine between the control and intervention groups. The lack of outcomes for the intervention was neither due to recruitment or the randomizing of participants nor due to dropouts. This study furthermore supports other findings concerning the lack of asthma control in the asthma population. Conclusion: Short Messaging Service is a reliable, convenient, affordable, secure, widespread, and a feasible technology for communication between the patient and healthcare system. However, even given the poor level of asthma control determined at the baseline, this study clearly documents that an SMS compliance and monitoring intervention design, like the one presented in this article, does not improve asthma control, nor does it generate fewer contacts with the healthcare system or improve the use of medicines.

Initial analytic validation of automated bone scan measures for treatment response assessment in patients with metastatic castration-resistant prostate cancer (CRPC).

e15174 Background: Evaluation of novel therapies for patients with CRPC has been limited by the lack of validated quantitative measures of bone tumor burden. Tools including visual assessment for determining progression based on lesion count and semi quantitative measures including the Bone Scan Index for predicting survival have been proposed. To date, a validated quantitative measure that can be used to assess either progression or response has not been available. We have developed a computer-aided (CAD) system for measurement of bone scan tumor burden including lesion count (LC), mean intensity (MI) and total area (TA). This study is to assess the range of normal variation and potential clinically meaningful cut points for changes in bone scan tumor burden. Methods: From an anonymized image data set, 20 CRPC patients were selected with a pair of bone scans acquired 6 to 24 weeks apart. All patients had failed at least 2nd line drug therapy; 10 were on no therapy, 10 received drug therapy between the two scans. Scans were acquired at 12 sites using a standard of care protocol including 20-25 mCi of Tc MDP, injected 2-4 hours before whole body scintigraphy. An automated CAD system was run for each patient on bone scans. Degenerative joint disease was removed manually by one of two board certified Nuclear Medicine Physicians. A two-sample Wilcoxon rank sum (Mann-Whitney) test was used to test for differences between the two groups in the ratio of LC (visit 2 / visit 1), change in MI and % change in tumor TA. Results: Table shows the median (IQR) for ratio of LC, change in MI and % change in TA. Differences between groups were significant for all measures. Conclusions: This preliminary data suggests total bone scan tumor area may be useful as an early surrogate outcome for CRPC patients with 30% change from baseline as a potential cut point to distinguish responders from non-responders. This work lays a foundation for validation of these measures against other clinically relevant outcome measures in a larger cohort. Ratio of LC Change in MI % change in TA No therapy 1.24 (0.56) -1.40 (14.80) 7.13 (27.61) Drug therapy 0.54 (0.68) -17.60 (16.30) -73.76 (45.38) P value 0.0012 0.0019 0.0003

Comparing MicroRNA Expression In Aggressive and Indolent Non-Hodgkin Lymphomas Identifies a Prognostic Signature for Mantle Cell Lymphoma

AbstractAbstract 800Mantle cell lymphoma (MCL) is a B-cell non-Hodgkin lymphoma (NHL) accounting for ~6% of all NHL. It is sensitive to combination chemotherapy, but remission durations are short without approaches such as stem cell transplantation (SCT). Most patients are incurable, but the clinical course is variable, with some patients succumbing quickly, while others survive >10 years. MicroRNAs (miRs) are small, non-coding RNAs that regulate gene expression by inhibiting mRNA translation. miRs are useful in the prognostic assessment of tumors, but work to date examining differences between MCL and normal lymphoid tissues, have only identified 2 miRs involved in MCL prognosis (Zhao JJ, Blood, 2010; Di Lisio L, Leukemia, 2010). We used a novel approach to identify a prognostic miR signature in MCL. We hypothesized that a miR signature defining aggressiveness can be obtained by comparing miR expression profiles of aggressive NHL with indolent NHL, and that this signature when applied to a set of MCL cases, may aid in MCL prognosis. Total RNA was extracted from 135 formalin-fixed paraffin-embedded samples obtained at primary diagnosis (Table 1). RNA from a training set of 19 indolent and 20 aggressive NHL cases was analyzed on a high-throughput quantitative real-time PCR (qRT-PCR) platform assessing the expression of 365 miRs and 3 endogenous controls (TaqMan Human MicroRNA Array v1.0: TLDA, ABI) using the DDCt method. A two-sample Wilcoxon Rank sum test corrected for false discovery rate was used to assess the significance of differential expression for each miR between aggressive and indolent NHL. The 14 most significantly differentially expressed miRs (p<0.001, FDR<0.02) were validated on an independent set of 25 indolent NHL and 19 aggressive NHL by qRT-PCR, and analyzed using the DDCt method. Univariate analysis using a one-sided t-test yielded 9 miRs that validated on the independent NHL set. Multivariable analysis demonstrated the ability of this 9 miR signature to distinguish between aggressive and indolent NHL (p<0.0001). Applying this signature to a set of 32 MCL patients with complete outcome data (Table 2) separated a poor prognosis group (median OS: 15 months, range: 4–40 months) from a good prognosis group (median OS: 88 months, range: 41–131 months) (Fig. 1). Among the 9 miRs were miR-29c, shown to have some prognostic value in MCL by Zhao et al., and miR-26a, shown to be important in MCL pathogenesis by Di Lisio et al. In light of the overlap with such recent studies, we believe the 9 miR prognostic signature we have identified may be of clinical utility. We are currently identifying mRNA targets for this miR signature and validating both the signature and the deregulated expression of these targets on a larger set of 200 MCL samples with known outcome data. [Display omitted] Table 1Sample breakdownTraining setNumberAggressive casesDiffuse large B-cell lymphoma5Primary mediastinal B-cell lymphoma5Burkitt lymphoma5Atypical Burkitt5Indolent casesSmall lymphocytic lymphoma/CLL5Extranodal marginal zone lymphoma5Follicular lymphomaGrade 13Grade 23Grade 3a3Validation setAggressive casesDiffuse large B-cell lymphoma7Primary mediastinal B-cell lymphoma5Burkitt lymphoma3Atypical Burkitt4Indolent casesSmall lymphocytic lymphoma/CLL5Extranodal marginal zone lymphoma5Follicular lymphomaGrade 15Grade 25Grade 3a5MCL casesConventional19Blastoid/pleomorphic11Prolymphocytoid1Multiple lymphomatoid polyposis1Normal benign lymph nodes20TOTAL135Table 2MCL clinical dataFeaturesTotal%GenderMale2372Female928ECOG01238117532-339Stage1262825372241547B symptoms928Extranodal sites516Lines of therapy026114442393619439>4413Types of therapyObservation alone26Anthracycline-based1856Rituximab1444SCT39Bortezomib39Radiation1444MedianRangeAge (yrs)6937–90M-IPI score6.65.3–8.7Ki-67 (%)257.5–90Time to 1st treatment (months)0.80.1–99.1Overall survival (months)344–131 Disclosures:Kuruvilla:Hoffman LaRoche: Honoraria, Research Funding; Celgene: Research Funding; Amgen: Honoraria; Otsuka: Honoraria; Genzyme: Honoraria.

Laparoscopic (TEP) Versus Lichtenstein Inguinal Hernia Repair: A Comparison of Quality‐of‐Life Outcomes

Laparoscopic inguinal hernia repair has emerged as a viable alternative to the open procedure. To date, few studies have included validated measures of quality of life as end points. We compared quality-of-life outcomes following laparoscopic versus open repair of inguinal hernia. All laparoscopic repairs were performed via the totally extraperitoneal route (TEP). All open procedures were Lichtenstein repairs (LR). Hernia repairs performed between January 1999 and December 2006 were included in the study. Data was recorded prospectively and each TEP repair was matched with a LR for analysis. The SF-36 form was used to assess quality of life. Statistical significance was determined using the two-sample Wilcoxon rank-sum (Mann-Whitney) test. Three hundred fourteen procedures were performed during the study period, 164 (52%) had a TEP repair and 150 (48%) had a LR. Ninety TEP repairs were matched with 90 LR. Recurrence rates were 3% following TEP repair and 2% following LR. There was a significant difference between the laparoscopic and open groups in terms of physical function (p=0.0001), physical role (p<0.0001), bodily pain (p=0.0029), general health (p=0.0025), and emotional role (p<0.0001). There was no significant difference between the groups in terms of vitality (p=0.2501), mental health (p=0.08), or social functioning (p=0.1677). These data suggest that the TEP repair results in less postoperative pain, a quicker return to normal functional status, and improved quality-of-life outcomes with equivalent recurrence rates when compared to the LR.

Semi-Sequential One-Shot Monitoring of Small Disorders With Controlled Type I Error Rate

We propose a simple two-stage monitoring rule for detecting small disorders in a two-sample location problem. The proposed rule is based on ranks and hence is nonparametric in nature. In the first stage, we use a sequential monitoring scheme to decide the necessity of employing a location test at some point of time. If there is urgency, we simply use a two-sample Wilcoxon rank sum test in the second stage. This leads to a semi sequential one-shot monitoring procedure. We study some asymptotic performance of the proposed rule. We also present some numerical findings obtained through Monte Carlo studies. The proposed rule meets the challenge of controlling type I error rate in sequential monitoring of an incoming series of observations.

Defining Cerebrospinal Fluid White Blood Cell Count Reference Values in Neonates and Young Infants

Cerebrospinal fluid (CSF) white blood cell (WBC) counts for neonates and young infants are usually interpreted on the basis of values reported in reference texts or handbooks; however, current reference texts either present normal CSF parameters without citation or cite studies with significant limitations. The objective of this study was to determine accurate, age-specific reference values for CSF WBC counts in a large population of neonates and young infants. This cross-sectional study included patients who were aged < or =56 days and had a lumbar puncture performed in the emergency department from January 1, 2005, to June 30, 2007. Patients were excluded from analysis for conditions that are suspected to cause CSF pleocytosis, including traumatic lumbar puncture, serious bacterial infection, congenital infection, seizure, and presence of a ventricular shunt. Children who tested positive for enterovirus (EV) in the CSF by polymerase chain reaction were also excluded. Two-sample Wilcoxon rank-sum tests were used to compare median CSF WBC values of those who had negative EV testing with those who did not have EV testing. A total of 380 (36%) of 1064 patients met inclusion criteria; 54% were male, 15% were preterm, and 39% presented during EV season. The median CSF WBC count was significantly higher in infants who were aged < or =28 days (3/microL, 95th percentile: 19/microL) than in infants who were aged 29 to 56 days (2/microL, 95th percentile: 9/microL; P < .001). In both age groups, infants with a negative EV PCR had a higher upper bound of the 95% confidence interval of the mean values compared with infants who did not have EV testing performed. We determined age-specific CSF WBC reference values in a large cohort of neonates and young infants that can be used to interpret accurately the results of lumbar punctures in this population.

Staphylococcus Aureus colonization and bacteremia in children with cancer.

Abstract 3666Poster Board III-602 BackgroundStaphylococcus aureus is an important cause of blood stream infections in children and adults. In recent years, new strains of methicillin-resistant S. aureus (MRSA), also known as community-acquired (CA)-MRSA have been isolated from otherwise healthy individuals. These strains frequently carry the Panton-Valentine Leukocidin (PVL) leukotoxin and belong to spa type 8; USA300 genotype, which is the most common strain causing CA-MRSA infections in the U.S. The clinical course of infections with PVL-positive S.aureus strains appears to be more severe than infection from PVL-negative strains. Bacteremia due to these strains has been reported in children, adolescents and adults. It is not known if methcillin-resistance or infection with CA-MRSA strains adversely affects outcome in children with cancer. Colonization of MRSA in healthy children has increased significantly since 2001 and has shown to be a risk factor for subsequent infection. However the prevalence of nasal and rectal colonization with MRSA; in particular with PVL-positive strains and the relationship between colonization and infection is not known in children or adults with cancer. MethodsThe epidemiology of MRSA and methicillin-sensitive S.aureus (MSSA) bacteremia and prevalence of MRSA nasal and rectal colonization in children with cancer was retrospectively studied from 2000 to 2007. Medical record review included patient demographics, underlying disease and antimicrobial susceptibility patterns of the MRSA and MSSA bacteremia isolates. Molecular typing was performed by polymerase chain reaction (PCR) on all isolates for detection of the PVL genes. Staphylococcus cassette chromosome (SCC) mec and spa typing was performed on all PVL-positive MRSA and MSSA bacteremia isolates and MRSA isolates causing colonization and infection. Demographic and treatment variables were compared between patients with MRSA and MSSA bacteremia and patients with PVL-positive and PVL-negative MRSA and MSSA bacteremia using exact two-sample Wilcoxon rank sum test or robust rank sum test for unequal variances and Fisher's exact chi-square test. The trend of MRSA/MSSA bacteremia and MRSA colonization was evaluated by logistic regression models. ResultsTen (19%) MRSA and 42 (81%) MSSA isolates from clinically distinct infectious bacteremic episodes were collected from 52 patients with cancer during the eight year study period. The proportion of cancer patients with MRSA, or MSSA bacteremia did not change significantly over the duration of the study. A third of the patients, 17 (33%), had complications. Thirty-eight (73%) of the bacteremic episodes were catheter-related. Catheters were removed significantly more often for MRSA infections than for MSSA infections for persistently positive blood cultures or complications (p=0.003). Subcutaneous ports was removed significantly more often than Hickman catheters (p= 0.005). The number of patients with persistently positive MRSA bacteremia were higher as compared to MSSA bacteremia (p= 0.004). Methicillin resistance was associated with decreased susceptibility to erythromycin (p=0.0003) and gentamicin (p=0.03). The difference in PVL positivity between MRSA and MSSA was statistically significant (P=0.01). None of the other variables studied including complications were significantly different between patients with MRSA or MSSA bacteremia or between patients with PVL-positive and PVL-negative S.aureus bacteremia. The number of patients colonized with MRSA compared to the total number of samples tested increased significantly between 2000-2001 and 2006-2007 (p=0.0007). PVL-positivity was associated both with increased colonization (p=0.004) and with an increased risk of infection (p=0.0005). There was a discordance in the spa types between the colonization and infection isolates. ConclusionsThis report represents the first description of the epidemiology of S.aureus bacteremia and colonization including analysis of PVL-positive strains in children with cancer. Methicillin-resistance or PVL-positivity did not appear to be associated with a worse outcome in our patient population. The number of patients colonized with MRSA increased significantly during this time period. PVL-positivity was associated with an increased risk of colonization and infection. Further studies are needed to confirm these observations in patients with cancer. Disclosures:No relevant conflicts of interest to declare.

Functional T Cell Array Reveals Pre-Treatment Expanded Terminal Effector Memory Response Is Associated with Lenalidomide Failure in Non-Del(5q) Myelodysplastic Syndrome.

Abstract 1759Poster Board I-785Lenalidomide (LEN) is a thalidomide derivative with proven efficacy for the treatment of patients with myelodysplastic syndrome (MDS). High rates of erythroid and cytogenetic response in patients with chromosome 5q deletion [del(5q)] produced the first FDA-approved karyotype-specific treatment for this disease. Transfusion-independence rates of approximately 25% have been reported previously for patients with non-[del(5q)] and efficacy in this population has been linked to the promotion of erythroid differentiation. Because impaired erythroid differentiation in lower-risk MDS may occur through several pathophysiological mechanisms, the identification of additional factors with predictive value for both response and failure to LEN are needed to optimize success of treatment. In addition to affecting erythroid differentiation, LEN has well-known potential for immune modulation and generates highly potent effector T cell responses in vitro and in vivo by potentiating T cell receptor signaling. Immune deregulation mediated by autoreactive effector T cells has been linked to impaired erythropoiesis and granulopoiesis in a distinct subset of MDS patients raising the question of whether LEN impacts the disease process in this subset of patients. To understand the relationship between T cell deregulation and LEN response, we conducted a pilot study of 13 low/INT-1-risk non-del (5q) MDS patients (7 responders and 6 non-responders) treated with LEN and determined 23 covariates related to functional T cell response measured prior to treatment and then correlated to treatment outcome. Of these 23 covariates, multiple T cell immune parameters were analyzed but were not associated with response including interferon-g (IFNg) production by CD4+ T cells (p=0.9) and CD8+ T cells (p=0.27), Tumor Necrosis Factor (TNF)-a production by CD4+ T cells (p=1.0) and CD8+ T cells (p=0.8), TCR-associated proliferation within the CD4+ (p=1.0) and CD8+ (p=0.4) compartment, CD4/CD8 ratio (p=0.3), percentage of CD4+ (p=0.5) and CD8+ (p=0.5) T lymphocytes, and the percentage of naïve and three different types of memory CD4+ T cells. Analysis was performed using two-group comparison statistical tests (two-sample t-test and Wilcoxon rank sum test) to compare responders (R) vs non-responders (NR). Only one factor was independently linked to LEN response. Results showed that a higher percentage of CD8 T cells (mean 56% in NR vs 32% in R) with a Terminal Effector Memory [TEM]) phenotype (CD45RA+/CD62L-) was associated with LEN failure (p=0.02). This population of T cells occurs at a low frequency in healthy individuals but can be induced to differentiate in vitro under constant exposure to long-term antigen and cytokine stimulation. We have shown previously that CD8+ TEM T cells are expanded in patients with impaired myelopoiesis due to immune dysregulation in Large Granular Lymphocyte (LGL) leukemia. In conclusion, these results suggest that CD8+ terminal effector memory expansion may be linked to immune deregulation in MDS and represents an important biomarker with negative predictive importance for LEN response in non-del(5q) low-risk MDS. DisclosuresNo relevant conflicts of interest to declare.

Pegfilgrastim Accelerates Neutrophil Engraftment, Reduces the Number of Neutropenic and Hospitalization Days and the Use of Antibiotics After Autologous Peripheral Blood Stem Cell Transplant for Multiple Myeloma and Lymphoma. A Phase II Study and Comparison with a Filgrastim Treated Historical Cohort.

Abstract 2274Poster Board II-251 Introduction:Granulocyte Colony-Stimulating Factor (G-CSF) is regularly used after autologous peripheral blood stem cell transplant (ASCT) to accelerate neutrophil engraftment. The result is a reduction of the number of febrile days, antibiotic use and duration of hospitalization, resulting in a reduction of costs. Randomized trails demonstrated that further cost reduction is obtained by delaying the beginning of G-CSF therapy from day 1 to days 5-7 post transplant without significantly changing the time to neutrophil recovery, despite a trend to better results when the drug was started on day 1. Pegfilgrastim is a sustained duration form of filgrastim administered as a single-fixed s.c. dose, a schedule that is more patient friendly. Moreover, as the drug is given in a single shot, there is no need to delay the therapy to decrease treatment costs. This trial was conducted to assess the efficacy and safety of pegfilgrastim to enhance neutrophil recovery after ASCT. Patients and Methods:in this bi-institutional phase II trial 40 patients with Multiple Myeloma (N=20), Hodgkin Lymphoma (N=8) and Non-Hodgkin Lymphoma (N=12) were accrued from January 2007 to December 2008. Pegfilgrastim 6 mg s.c. was administered on transplant day 1. Results were compared with a historical control group of 40 patients (20 with myeloma and 20 with lymphoma) treated with filgrastim 5μg/kg/d s.c. starting at median day 7 after transplant (range 3-7). All lymphoma patients (cases and controls) received BEAM as high dose schedule, while the 40 multiple myeloma patients were treted with MEL200. If tandem transplants were planned, only the first procedure was eligible to the study. Differences between groups were estimated by two-sample t-test and Wilcoxon rank-sum test. A two sided p-value of <0.05 was considered statistically significant. Results:case and control populations were statistically similar in terms of age, sex, disease, conditioning regimen, CD34+ cell-dose and number of prior therapy lines. Median time to achieve a neutrophil count > 500/μl was 9.5 vs 11.3 days for case and controls, respectively (p<0.0001); median duration of neutropenia was 5.8 vs 7.4 days (p=0.0001); median time to platelet count > 20000/μl was 11.9 vs 11.4 days (p=0.42); median duration of fever was 3.4 vs 4.6 days (p=0.3); median duration of i.v. antibiotic therapy was 4.2 vs 6.5 days (p=0.0007); median hospitalization duration was 14 vs 14.8 days (p=0.0184, N.S. at t-test). Both groups received an equal number of RBC and platelet transfusions. Pain was present in 12.5% of patients in the experimental group and lasted for a median of 3 days (2-9). No other toxicities related to pegfilgrastim were observed. The control group received a median of 6.5 doses of filgrastim (range 4-10). Market prices per treatment are 2076.75 vs 1534.90 Swiss Francs for pegfilgrastim and filgrastim, respectively. Conclusions:Pegfilgrastim given as a single dose of 6 mg s.c. on transplant day 1 accelerates neutrophil engraftment, shortens the duration of neutropenia and hospitalization and reduces the use of i.v. antibiotics compared to daily filgrastim. The 25% increase in costs when using pegfilgrastim is counterbalanced by a shorter time on antibiotics and a tendency to a shorter time in hospital. Disclosures:Wannesson:AMGEN: Research Funding. Off Label Use: Pegfilgrastim is a pegilated formulation of filgrastim, a reccombinant human granulocyte colony stimulating factor. It has a long half life allowing a single dose treatment instead of multiple repeated doses. In general it has been shown equivalent results comparing to filgrastim in all clinical settings, even if still off-label for some indications, like the post-autologous transplant support (matter of the present abstract). Ghielmini:AMGEN: Research Funding. Ketterer:AMGEN: Research Funding.

Atherogenic, enlarged, and dysfunctional HDL in human PLTP/apoA-I double transgenic mice

In low density lipoprotein receptor (LDLR)-deficient mice, overexpression of human plasma phospholipid transfer protein (PLTP) results in increased atherosclerosis. PLTP strongly decreases HDL levels and might alter the antiatherogenic properties of HDL particles. To study the potential interaction between human PLTP and apolipoprotein A-I (apoA-I), double transgenic animals (hPLTPtg/hApoAItg) were compared with hApoAItg mice. PLTP activity was increased 4.5-fold. Plasma total cholesterol and phospholipid were decreased. Average HDL size (analyzed by gel filtration) increased strongly, hPLTPtg/hApoAItg mice having very large, LDL-sized, HDL particles. Also, after density gradient ultracentrifugation, a substantial part of the apoA-I-containing lipoproteins in hPLTPtg/hApoAItg mice was found in the LDL density range. In cholesterol efflux studies from macrophages, HDL isolated from hPLTPtg/hApoAItg mice was less efficient than HDL isolated from hApoAItg mice. Furthermore, it was found that the largest subfraction of the HDL particles present in hPLTPtg/hApoAItg mice was markedly inferior as a cholesterol acceptor, as no labeled cholesterol was transferred to this fraction. In an LDLR-deficient background, the human PLTP-expressing mouse line showed a 2.2-fold increased atherosclerotic lesion area. These data demonstrate that the action of human PLTP in the presence of human apoA-I results in the formation of a dysfunctional HDL subfraction, which is less efficient in the uptake of cholesterol from cholesterol-laden macrophages.

Serum Interleukin-6 as a Marker of Periprosthetic Infection Following Total Hip and Knee Arthroplasty

The erythrocyte sedimentation rate, the C-reactive protein serum level, and the white blood-cell count are routinely used to diagnose periprosthetic infection. In the present study, the diagnostic accuracy of the interleukin-6 serum level was compared with the accuracy of these standard tests for the evaluation of a group of patients who had had a total hip or total knee arthroplasty and were undergoing a reoperation for the treatment of an infection or another implant-related problem. A prospective, case-control study of fifty-eight patients who had had a total hip or knee replacement and were undergoing a reoperation because of an infection (seventeen patients) or another implant-related problem (forty-one patients) was conducted. The serum levels of interleukin-6 and C-reactive protein, the erythrocyte sedimentation rate, and the white blood-cell count were measured. The definitive diagnosis of an infection was determined on the basis of positive histopathological evidence of infection and growth of bacteria on culture of intraoperative specimens. Two-sample Wilcoxon rank-sum (Mann-Whitney) tests were used to determine the presence of a significant difference between patients with and without infection with regard to each laboratory value studied. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of each text were also calculated. The serum interleukin-6 level, erythrocyte sedimentation rate, and C-reactive protein level were significantly higher in patients who had an infection than in those who did not, both when all patients were considered together and when the total hip arthroplasty and total knee arthroplasty groups were considered separately. With the numbers available, there was no significant difference with regard to the white blood-cell count between patients with and without infection. With a normal serum interleukin-6 level defined as <10 pg/mL, the serum interleukin-6 test had a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 1.0, 0.95, 0.89, 1.0, and 97%, respectively. An elevated serum interleukin-6 level correlated positively with the presence of periprosthetic infection in patients undergoing a reoperation at the site of a total hip or knee arthroplasty. The serum interleukin-6 level is valuable for the diagnosis of periprosthetic infection in patients who have had a total hip or total knee arthroplasty.

SERUM INTERLEUKIN-6 AS A MARKER OF PERIPROSTHETIC INFECTION FOLLOWING TOTAL HIP AND KNEE ARTHROPLASTY

Background: The erythrocyte sedimentation rate, the C-reactive protein serum level, and the white blood-cell count are routinely used to diagnose periprosthetic infection. In the present study, the diagnostic accuracy of the interleukin-6 serum level was compared with the accuracy of these standard tests for the evaluation of a group of patients who had had a total hip or total knee arthroplasty and were undergoing a reoperation for the treatment of an infection or another implant-related problem. Methods: A prospective, case-control study of fifty-eight patients who had had a total hip or knee replacement and were undergoing a reoperation because of an infection (seventeen patients) or another implant-related problem (forty-one patients) was conducted. The serum levels of interleukin-6 and C-reactive protein, the erythrocyte sedimentation rate, and the white blood-cell count were measured. The definitive diagnosis of an infection was determined on the basis of positive histopathological evidence of infection and growth of bacteria on culture of intraoperative specimens. Two-sample Wilcoxon rank-sum (Mann-Whitney) tests were used to determine the presence of a significant difference between patients with and without infection with regard to each laboratory value studied. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of each text were also calculated. Results: The serum interleukin-6 level, erythrocyte sedimentation rate, and C-reactive protein level were significantly higher in patients who had an infection than in those who did not, both when all patients were considered together and when the total hip arthroplasty and total knee arthroplasty groups were considered separately. With the numbers available, there was no significant difference with regard to the white blood-cell count between patients with and without infection. With a normal serum interleukin-6 level defined as <10 pg/mL, the serum interleukin-6 test had a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 1.0, 0.95, 0.89, 1.0, and 97%, respectively. Conclusions: An elevated serum interleukin-6 level correlated positively with the presence of periprosthetic infection in patients undergoing a reoperation at the site of a total hip or knee arthroplasty. The serum interleukin-6 level is valuable for the diagnosis of periprosthetic infection in patients who have had a total hip or total knee arthroplasty. Level of Evidence: Diagnostic Level IV. See Instructions to Authors for a complete description of levels of evidence.