Socioeconomic Disparities in Anal Cancer: Effect on Treatment Delay and Survival.

BACKGROUND: Socioeconomic inequities have implications for access to health care and may be associated with disparities in treatment and survival. OBJECTIVE: To investigate the impact of socioeconomic inequities on time to treatment and survival of anal squamous-cell carcinoma. DESIGN: This is a retrospective study using a nationwide data set. SETTINGS: The patients were selected from the National Cancer Database and enrolled from 2004 to 2016. PATIENTS: We identified patients with stage I to III squamous-cell carcinoma of the anus who were treated with chemoradiation therapy. MAIN OUTCOMES MEASURES: Socioeconomic factors, including race, insurance status, median household income, and percentage of the population with no high school degrees, were included. The association of these factors with treatment delay and overall survival was investigated. RESULTS: A total of 24,143 patients who underwent treatment for grade I to III squamous-cell carcinoma of the anus were identified. The median age was 60 years, and 70% of patients were women. The median time to initiation of treatment was 33 days. Patients from zip codes with lower median income, patients with a higher percentage of no high school degree, and patients with other government insurance followed by Medicaid insurance had treatment initiated after 60 days from diagnosis. Kaplan-Meier survival analysis showed that the late-treatment group had worse overall survival compared to the early treatment group (98 vs 125 months; p < 0.001). LIMITATIONS: No detailed information is available about the chemoradiotherapy regimen, completion of treatment, recurrence, disease-free survival, and individual-level socioeconomic condition and risk factors. CONCLUSION: Patients from communities with lower median income, level of education, and enrolled in public insurance had longer time to treatment. Lower socioeconomic status was also associated with poorer overall survival. These results warrant further analysis and measures to improve access to care to address this disparity. See Video Abstract . DESIGUALDADES SOCIOECONMICAS EN CASOS DE CNCER ANAL EFECTOS EN EL RETRASO DEL TRATAMIENTO Y LA SOBREVIDA: ANTECEDENTES:Las desigualdades socio-económicas tienen implicaciones en el acceso a la atención médica y pueden estar asociadas con disparidades en el tratamiento y la sobrevida.OBJETIVO:Indagar el impacto de las desigualdades socio-económicas sobre el tiempo de retraso en el tratamiento y la sobrevida en casos de carcinoma a células escamosas del ano (CCEA).DISEÑO:Estudio retrospectivo utilizando un conjunto de datos a nivel nacional.AJUSTES:Todos aquellos pacientes inscritos entre 2004 a 2016 y que fueron seleccionados de la Base Nacional de Datos sobre el Cáncer.PACIENTES:Identificamos pacientes con CCEA en estadíos I-III y que fueron tratados con radio-quimioterápia.PRINCIPALES MEDIDAS DE RESULTADOS:Se incluyeron factores socio-económicos tales como la raza, el tipo de seguro de salud, el ingreso familiar medio y el porcentaje de personas sin bachillerato de secundaria (SBS). Se investigó la asociación entre estos factores con el retraso en iniciar el tratamiento y la sobrevida global.RESULTADOS:Se identificaron un total de 24.143 pacientes que recibieron tratamiento para CCEA estadíos I-III. La mediana de edad fue de 60 años donde 70% eran de sexo femenino. La mediana del tiempo transcurrido desde el diagnóstico hasta el inicio del tratamiento fue de 33 días. Los pacientes residentes en zonas de código postal con ingresos medios más bajos, con un mayor porcentaje de individuos SBS y los pacientes con otro tipo de seguro gubernamental de salud, seguidos del seguro tipo Medicaid iniciaron el tratamiento solamente después de 60 días al diagnóstico inicial de CCEA. El análisis de Kaplan-Meier de la sobrevida mostró que el grupo de tratamiento tardío tuvo una peor supervivencia general comparada con el grupo de tratamiento precoz o temprano (98 frente a 125 meses; p <0,001).LIMITACIONES:No se dispone de información detallada sobre el tipo de radio-quimioterapia utilizada, ni sobre la finalización del tratamiento o la recurrencia, tampoco acerca de la sobrevida libre de enfermedad ni sobre las condiciones socio-económicas o aquellos factores de riesgo a nivel individual.CONCLUSIÓN:Los pacientes de comunidades con ingresos medios más bajos, con un nivel de educación limitado e inscritos en un seguro público tardaron mucho más tiempo en recibir el tratamiento prescrito. El nivel socio-económico más bajo también se asoció con una sobrevida global más baja. Los presentes resultados justifican mayor análisis y medidas mas importantes para mejorar el acceso a la atención en salud y poder afrontar esta disparidad. (Traducción-Dr. Xavier Delgadillo ).

Phase I dose-escalation study of procaspase-activating compound-1 in combination with temozolomide in patients with recurrent high-grade astrocytomas.

Background: Procaspase-3 (PC-3) is overexpressed in various tumor types, including gliomas. Targeted PC-3 activation combined with chemotherapy is a novel strategy for treating patients with high-grade gliomas, with promising preclinical activity. This study aimed to define safety and tolerability of procaspase-activating compound-1 (PAC-1) in combination with temozolomide (TMZ) for patients with recurrent high-grade astrocytomas. Methods: A modified-Fibonacci dose-escalation 3 + 3 design was used. PAC-1 was administered at increasing dose levels (DL; DL1 = 375 mg) on days 1-21, in combination with TMZ 150 mg/m2/5 days, per 28-day cycle. Dose-limiting toxicity was assessed during the first 2 cycles. Neurocognitive function (NCF) testing was conducted throughout the study. Results: Eighteen patients were enrolled (13 GBM, IDH-wild type; 2 astrocytoma, IDH-mutant, grade 3; 3 astrocytoma, IDH-mutant, grade 4). Dose escalation was discontinued after DL3 (ie, PAC-1, 625 mg) due to lack of additional funding. Grade 3 toxicity was observed in 1 patient at DL1 (elevated liver transaminases) and 1 at DL 2 (headache). Two partial responses were observed at DL1 in patients with GBM, O6-methylguanine-DNA methyltransferase (MGMT) promoter methylated. Two patients had stable disease, and 11 experienced progression. NCF testing did not show a clear relationship between PAC-1 dose, treatment duration, and declines in NCF. Conclusions: Combination of PAC-1 and TMZ was well tolerated up to 625 mg orally daily and TMZ orally 150 mg/m2/5 days per 28-day cycle. The maximum tolerated dose was not reached. Further dose escalation of PAC-1 in combination with TMZ is advised before conducting a formal prospective efficacy study in this patient population.

Phase I study of procaspase-activating compound-1 (PAC-1) in the treatment of advanced malignancies.

BACKGROUND: Procaspase-3 (PC-3) is overexpressed in multiple tumour types and procaspase-activating compound 1 (PAC-1) directly activates PC-3 and induces apoptosis in cancer cells. This report describes the first-in-human, phase I study of PAC-1 assessing maximum tolerated dose, safety, and pharmacokinetics. METHODS: Modified-Fibonacci dose-escalation 3 + 3 design was used. PAC-1 was administered orally at 7 dose levels (DL) on days 1-21 of a 28-day cycle. Dose-limiting toxicity (DLT) was assessed during the first two cycles of therapy, and pharmacokinetics analysis was conducted on days 1 and 21 of the first cycle. Neurologic and neurocognitive function (NNCF) tests were performed throughout the study. RESULTS: Forty-eight patients were enrolled with 33 completing ≥2 cycles of therapy and evaluable for DLT. DL 7 (750 mg/day) was established as the recommended phase 2 dose, with grade 1 and 2 neurological adverse events noted, while NNCF testing showed stable neurologic and cognitive evaluations. PAC-1's t1/2 was 28.5 h after multi-dosing, and systemic drug exposures achieved predicted therapeutic concentrations. PAC-1 clinical activity was observed in patients with neuroendocrine tumour (NET) with 2/5 patients achieving durable partial response. CONCLUSIONS: PAC-1 dose at 750 mg/day was recommended for phase 2 studies. Activity of PAC-1 in treatment-refractory NET warrants further investigation. CLINICAL TRIAL REGISTRATION: Clinical Trials.gov: NCT02355535.

Race/ethnicity and underlying disease influences hematopoietic stem/progenitor cell mobilization response: A single center experience.

BACKGROUND: Whether race/ethnicity plays a role in hematopoietic stem/progenitor cells (HSPC) mobilization in autologous donors has not been studied. We hypothesize that donor characteristic including race/ethnicity, age, sex, body mass index, and diagnostic groups influences HSPC mobilization. Diagnostic groups include healthy allogeneic donors, autologous multiple myeloma (MM) and non-MM donors. STUDY DESIGN AND METHODS: Here, we conducted a single-center retrospective study in 64 autologous patients and 48 allogeneic donors. Autologous donors were patients diagnosed with MM or non-MM. All donors were grouped as African American (AA), White (W), or "Other"(O). RESULTS: Multivariate analysis demonstrated diagnostic group differences for CD34+ cell yields between race/ethnicity. Specifically, non-MM patients had the lowest CD34+ cell yields in AA and O, but not in W. For pre-apheresis peripheral blood (PB) CD34+ cell numbers, race/ethnicity had a significant effect both in bivariate and multivariate analyses. Non-MM patients had the lowest, and AA patients had the highest PB CD34+ cells. The results support the view that past therapies used in MM are likely more conducive of recovery of HSPC. CONCLUSIONS: Our study shows that race/ethnicity and diagnostic group differences influenced CD34+ cell mobilization response across donor types. Interestingly, autologous MM donors with the aid of plerixafor displayed comparable CD34 yields to allogeneic donors. Even though both MM and non-MM donors received plerixafor, non-MM donors had significantly lower CD34 yields among AA and O donors but not in W donors. Larger studies would be required to validate the role of diagnostic groups and race/ethnicity interactions.

Phase 1 study of TTC-352 in patients with metastatic breast cancer progressing on endocrine and CDK4/6 inhibitor therapy.

PURPOSE: TTC-352 is a selective human estrogen receptor (ER) partial agonist developed for treatment of hormone-refractory ER + breast cancer. METHODS: This was an accelerated dose escalation study with the primary endpoint of maximum tolerated dose that evaluated five dose levels of TTC-352 in breast cancer progressing after at least two lines of hormonal therapy including one in combination with a CDK4/6 inhibitor. The secondary objectives were to determine treatment tolerability, pharmacokinetics of TTC-352, best response, progression-free survival (PFS), and PKCα expression in tumors. RESULTS: The study enrolled 15 patients. No dose-limiting toxicity was observed. Patients experienced the following grade 3 toxicities: asymptomatic pulmonary embolism, diarrhea, aspartate transaminase elevation, and myalgia, and one grade 4 toxicity of gamma glutamyltransferase elevation. Pharmacokinetic half-life was 7.6-14.3 h. The intra- and inter-individual variability for AUC0-∞ hampered assessment of the relationship between dose and AUC0-∞. Median PFS was 58 days (95% CI = 28,112). Higher PKCα expression in tumor stroma was associated with a trend toward longer PFS. CONCLUSIONS: TTC-352 demonstrates safety and early clinical evidence of antitumor activity against heavily pretreated hormone-refractory breast cancer. Based upon TTC-352 plasma concentrations and tolerability, the 180 mg twice a day is recommended for further testing. (ClinicalTrials.gov Identifier: NCT03201913).

Phase Ib/II Clinical Trial of Pembrolizumab With Bevacizumab for Metastatic Renal Cell Carcinoma: BTCRC-GU14-003.

PURPOSE: We hypothesized that bevacizumab will potentiate activity of pembrolizumab. We conducted a phase Ib/II, single-arm, multisite clinical trial of the combination in metastatic renal cell carcinoma (RCC). PATIENTS AND METHODS: Patients with metastatic clear cell RCC who experienced progression after at least one systemic therapy (phase Ib) or were treatment naïve (phase II) were enrolled. In phase Ib, pembrolizumab (200 mg) and bevacizumab (10 or 15 mg/kg) were given intravenously every 3 weeks. The primary end point for phase II was overall response rate (ORR). With an 80% statistical power and a type I error probability of 0.1, 48 patients were to be accrued to detect an ORR of 42%. RESULTS: Thirteen patients (ages 33-68 years; median, 55 years) were enrolled in the phase Ib study. No dose-limiting toxicities were reported. Pembrolizumab 200 mg and bevacizumab 15 mg/kg were chosen for phase II. Forty-eight patients (ages 42-84 years; median age, 61 years; 33 males) were accrued for the phase II study. The primary end point was met, with the ORR reaching 60.9% (95% CI, 45.4% to 74.9%), consisting of 1 complete response (CR), 2 CRs in target lesions, 25 partial responses, 18 responses of stable disease, 2 unevaluable responses. Median progression-free survival was 20.7 months (95% CI, 11.3 to 27.4 months). Median overall survival was not reached at the median follow-up of 28.3 months. The most common treatment-related grade 3 toxicities were hypertension and proteinuria. There were two grade 4 toxicities: duodenal ulcer and hyponatremia. Presence of tumor-infiltrating T cells, but not programmed death-ligand 1 expression, in tumor tissue correlated with response. CONCLUSION: The combination of 200 mg of pembrolizumab and a 15 mg/kg dose of bevacizumab given every 3 weeks is safe and active in metastatic RCC.

Phase I Study of IGF-Methotrexate Conjugate in the Treatment of Advanced Tumors Expressing IGF-1R.

OBJECTIVES: Insulin-like growth factor-methotrexate (IGF-MTX) is a conjugate of methotrexate and 765IGF, a variant of IGF-1 with high affinity for insulin-like growth factor type 1 receptor. The study aim was to determine the maximum tolerated dose of IGF-MTX in refractory solid organ and hematologic malignancies expressing insulin-like growth factor type 1 receptor. MATERIALS AND METHODS: This phase I trial used a modified toxicity probability interval design with 5 cohort dose levels, and expansion cohort at maximum tolerated dose. IGF-MTX was given intravenously over 90 minutes on days 1, 8, and 15 of a 28-day cycle. RESULTS: A total of 17 patients were enrolled. The highest tolerated dose tested was 0.80 µEq/kg with dose-limiting toxicity of grade 3 hypoglycemia. Drug-related grade 3 and 4 toxicities included abdominal pain (26%), hypoglycemia (10%), and hypotension (10%). Of the 15 evaluable for response, 3 patients (20%) had stable disease, including the patient with Hodgkin lymphoma with stable disease for 12 cycles of therapy. IGF-MTX concentrations declined rapidly, with half-lives of 5.2 to 14 minutes for the initial distribution phase and 6.5 to 7.5 hours for the terminal elimination phase. Higher IGF-R1 expression did not correlate with better outcome. CONCLUSIONS: IGF-MTX is well tolerated. IGF-MTX pharmacokinetics suggest rapid cellular uptake. The activity of IGF-MTX in Hodgkin lymphoma should be explored.

Lipodisqs for eukaryote lipidomics with retention of viability: Sensitivity and resistance to Leucobacter infection linked to C.elegans cuticle composition.

Lipodisq™ nanoparticles have been used to extract surface lipids from the cuticle of two strains (wild type, N2 and the bacteria-resistant strain, agmo-1) of the C. elegans nematode without loss of viability. The extracted lipids were characterized by thin layer chromatography and MALDI-TOF-MS. The lipid profiles differed between the two strains. The extracted lipids from the bacteria-resistant strain, agmo-1, contained ether-linked (O-alkyl chain) lipids, in contrast to the wild-type strain which contained exclusively ester- linked (O-acyl) lipids. This observation is consistent with the loss of a functional alkylglycerol monooxygenase (AGMO) in the bacterial resistant strain agmo-1. The presence and abundance of other lipid species also differs between the wild-type N2 and agmo-1 nematodes, suggesting that the agmo-1 mutant strain attempts to compensate for the increase in ether-linked lipids by modulating other lipid-synthesis pathways. Together these differences not only affect the fragility of the cuticle and the buoyancy of the worm in aqueous buffer, but also interactions with surface-adhering bacteria. The much greater chemical stability of O-alkyl, non-hydrolysable linked lipids compared with hydrolysable O-acyl linked lipids, may be the origin of the resistance of the agmo-1 strain to bacterial infection, providing a more resilient cuticle for the nematode. Additionally, we show that lipid extraction with a polymer of styrene and maleic acid (SMA) provides a viable route to lipidomics studies with minimal perturbation of the organism.

Phase I Study of Aurora A Kinase Inhibitor Alisertib (MLN8237) in Combination With Selective VEGFR Inhibitor Pazopanib for Therapy of Advanced Solid Tumors.

OBJECTIVES: Pazopanib is a multikinase angiogenesis inhibitor. Alisertib is a highly selective inhibitor of mitotic Aurora A kinase. There is preclinical evidence that mitosis-targeting agents exhibit antiangiogenic effects. Thus, the combination of these 2 agents may have a synergistic effect on tumor vasculature. The primary objective of this study is to determine the optimal tolerated dose (OTD) for alisertib and pazopanib. MATERIALS AND METHODS: This phase 1b study evaluated the OTD of alisertib twice a day, on days 1 to 7 with pazopanib, once a day, continuously in a 21-day cycle, both taken orally. Disease response was assessed using the Response Evaluation Criteria in Solid Tumors version 1.1 every 2 cycles. OTD cohort was expanded to assure safety and perform pharmacokinetics analysis. RESULTS: A total of 27 patients received treatment. Seventy-seven percent of the patients had received at least 3 prior chemotherapy regimens. Dose-limiting toxicities occurred in dose level (DL) 2+ (grade 4 thrombocytopenia and grade 3 mucositis) and DL 3 (grade 3 liver transaminases elevation and grade 3 abdominal pain). The OTD was determined to be DL 2: alisertib 20 mg twice daily and pazopanib 600 mg daily. Pharmacokinetic analysis revealed that clearance of alisertib was reduced by ∼40% in the presence of pazopanib compared with clearance in the absence of pazopanib. Fourteen patients had stable disease and 2 patients had a partial response. CONCLUSIONS: The combination of alisertib with pazopanib demonstrates manageable safety and early clinical evidence of antitumor activity in patients with advanced malignancies (NCT01639911).

Characterization of size-specific particulate matter emission rates for a simulated medical laser procedure--a pilot study.

Prior investigation on medical laser interaction with tissue has suggested device operational parameter settings influence laser generated air contaminant emission, but this has not been systematically explored. A laboratory-based simulated medical laser procedure was designed and pilot tested to determine the effect of laser operational parameters on the size-specific mass emission rate of laser generated particulate matter. Porcine tissue was lased in an emission chamber using two medical laser systems (CO2, λ = 10,600 nm; Ho:YAG, λ = 2100 nm) in a fractional factorial study design by varying three operational parameters (beam diameter, pulse repetition frequency, and power) between two levels (high and low) and the resultant plume was measured using two real-time size-selective particle counters. Particle count concentrations were converted to mass emission rates before an analysis of variance was used to determine the influence of operational parameter settings on size-specific mass emission rate. Particle shape and diameter were described for a limited number of samples by collecting particles on polycarbonate filters, and photographed using a scanning electron microscope (SEM) to examine method of particle formation. An increase in power and decrease in beam diameter led to an increase in mass emission for the Ho:YAG laser at all size ranges. For the CO2 laser, emission rates were dependent on particle size and were not statistically significant for particle ranges between 5 and 10 µm. When any parameter level was increased, emission rate of the smallest particle size range also increased. Beam diameter was the most influential variable for both lasers, and the operational parameters tested explained the most variability at the smallest particle size range. Particle shape was variable and some particles observed by SEM were likely created from mechanical methods. This study provides a foundation for future investigations to better estimate size-specific mass emission rates and particle characteristics for additional laser operational parameters in order to estimate occupational exposure, and to inform control strategies.

Evaluation of imputation methods for microbial surface water quality studies.

Longitudinal studies of microbial water quality are subject to missing observations. This study evaluates multiple imputation (MI) against data deletion, mean or median imputation for replacing missing microbial water quality data. The specific context is data collected in Chicago Area Waterway System (2007-2009), where 45% of Escherichia coli and 53% of enterococci densities were missing owing to sample analysis deficiencies. Imputation methods were compared performing a simulation study using complete observations with introduced missing values and subsequently compared with the original data with missing observations. Coefficients for E. coli densities in linear regression models predicting somatic coliphages density show that MI introduces the least bias among other methods while controlling Type I error. Further exploration of utilizing different MI implementations is recommended to address the influence of missing percentage on MI performance and to explore sensitivity to the degree of violation of the missing completely at random assumption.

Baseline knowledge survey of restaurant food handlers in suburban Chicago: do restaurant food handlers know what they need to know to keep consumers safe?

In the U.S., foodborne disease causes millions of illnesses annually, resulting in thousands of deaths. To reduce food poisoning, restaurant food handlers need accurate knowledge of food safety principles as a starting point for the outcome of optimal food safety behavior. The study described in this article determined food safety knowledge gaps among suburban Chicago restaurant food handlers. A cross-sectional survey of 729 food handlers at 211 suburban Chicago restaurants was conducted from June 2009 through February 2010. A 50-question survey was administered by a trained interviewer in either English or Spanish. Mixed-effects regression analysis identified risk factors associated with an overall food safety knowledge score. The mean overall knowledge score was only 72% and substantial knowledge gaps related to cross contamination, cooking, and holding and storage of food were identified. Spanish-speaking food handlers scored significantly lower than English-speaking food handlers (p < .05). Although certified food managers scored significantly higher than noncertified food handlers, their score was only 79%. These data provide targets for educational interventions to remedy knowledge gaps in food handlers in order to prevent food poisoning from restaurants.

Modeling nicotine dependence: an application of a longitudinal IRT model for the analysis of adolescent nicotine dependence syndrome scale.

INTRODUCTION: Measures of nicotine dependence typically use the item average or total score from rating scales, such as the Nicotine Dependence Syndrome Scale (NDSS). Alternatively, item response theory (IRT) methods can provide useful item-specific information. IRT methods developed for longitudinal data can additionally provide information about item-specific changes over time. METHODS: We describe a longitudinal 2-parameter ordinal IRT model, and compare the results from this model with those from an IRT model for only the baseline item responses, and a conventional longitudinal analysis of the item-average NDSS score. We examined a 10-item, adolescent version of the NDSS at baseline, 6, 15, and 24 months for 1,097 9th or 10th graders. RESULTS: IRT analysis of the baseline data revealed that the items "willing to go out of the house in a storm to find a cigarette," "choose to spend money on cigarettes than lunch," "function better after morning cigarette," and "worth smoking in cold or rain," were good items at distinguishing individuals' levels of nicotine dependency. While the analysis of the averaged NDSS score indicated linear growth over time, the longitudinal IRT method revealed that only 5 out of the 10 items showed statistical increase over time. CONCLUSIONS: Infrequently endorsed NDSS items were generally better able to distinguish higher levels of dependency. The endorsement of such items increased over time. Items that changed significantly over time reflected the general drive concept of dependence, as well as the total first overarching dimension of dependence.

Health risks of limited-contact water recreation.

BACKGROUND: Wastewater-impacted waters that do not support swimming are often used for boating, canoeing, fishing, kayaking, and rowing. Little is known about the health risks of these limited-contact water recreation activities. OBJECTIVES: We evaluated the incidence of illness, severity of illness, associations between water exposure and illness, and risk of illness attributable to limited-contact water recreation on waters dominated by wastewater effluent and on waters approved for general use recreation (such as swimming). METHODS: The Chicago Health, Environmental Exposure, and Recreation Study was a prospective cohort study that evaluated five health outcomes among three groups of people: those who engaged in limited-contact water recreation on effluent-dominated waters, those who engaged in limited-contact recreation on general-use waters, and those who engaged in non-water recreation. Data analysis included survival analysis, logistic regression, and estimates of risk for counterfactual exposure scenarios using G-computation. RESULTS: Telephone follow-up data were available for 11,297 participants. With non-water recreation as the reference group, we found that limited-contact water recreation was associated with the development of acute gastrointestinal illness in the first 3 days after water recreation at both effluent-dominated waters [adjusted odds ratio (AOR) 1.46; 95% confidence interval (CI): 1.08, 1.96] and general-use waters (1.50; 95% CI: 1.09, 2.07). For every 1,000 recreators, 13.7 (95% CI: 3.1, 24.9) and 15.1 (95% CI: 2.6, 25.7) cases of gastrointestinal illness were attributable to limited-contact recreation at effluent-dominated waters and general-use waters, respectively. Eye symptoms were associated with use of effluent-dominated waters only (AOR 1.50; 95% CI: 1.10, 2.06). Among water recreators, our results indicate that illness was associated with the amount of water exposure. CONCLUSIONS: Limited-contact recreation, both on effluent-dominated waters and on waters designated for general use, was associated with an elevated risk of gastrointestinal illness.

A comparison of rapid and conventional measures of indicator bacteria as predictors of waterborne protozoan pathogen presence and density.

E. coli and enterococci in recreational waters are monitored as indicators of fecal contamination, pathogen presence, and health risk. Quantitative polymerase chain reaction (qPCR) tests for fecal indicator bacteria can provide beach managers with same-day information about water quality, unlike culture methods which provide that information the following day. The abilities of qPCR measurements of indicator bacteria, as compared to culture measurements of indicator bacteria, as predictors of pathogen presence or density in surface waters are not well understood. The purpose of this study was to make such comparisons between water samples collected from Chicago area surface waters, including rivers, inland lakes, Lake Michigan, and the Chicago Area Waterways System, which is dominated by wastewater effluent. A total of 294 twenty-litre samples were collected and analyzed for Giardia and Cryptosporidium. qPCR and membrane filtration methods were used to quantify E. coli and enterococci. Correlation, logistic regression, and zero-inflated Poisson modeling were utilized to evaluate associations between indicators and parasites. qPCR and culture measures of the indicator bacteria were similar in their ability to predict parasite presence and density. Correlations between parasites and indicators were generally stronger at waters not dominated by effluent. Associations between indicator density and Giarida presence were observed more consistently than between indicator density and Cryptosporidium presence. Associations between enterococci and parasites were generally stronger than associations between E. coli and parasites. The use of qPCR monitoring in our setting would generate more timely results without compromising the ability to predict parasite presence or density.

Evaluating mediation in longitudinal multivariate data: mediation effects for the Aban Aya Youth Project drug prevention program.

This study illustrates a method to evaluate mediational mechanisms in a longitudinal prevention trial, the Aban Aya Youth Project (AAYP). In previous studies, interventions of AAYP were found to be effective in reducing the growth of violence, substance use and unsafe sex among African American adolescents. In this article, we hypothesized that the effects of the interventions in reducing the growth of substance use behavior were achieved through their effects in changing intermediate processes such as behavioral intentions, attitudes toward the behavior, estimates of peers' behaviors, best friends' behaviors, and peer group pressure. In evaluating these mediational mechanisms, difficulties arise because the growth trajectories of the substance use outcome variable and some of the mediating variables were curvilinear. In addition, all of the multivariate mediational measures had planned missing data so that a score from the multiple items for a mediator could not be formed easily. In this article, we introduce a latent growth modeling (LGM) approach; namely, a two-domain LGM mediation model, in which the growth curves of the outcome and the mediator are simultaneously modeled and the mediation effects are evaluated. Results showed that the AAYP intervention effects on adolescent drug use were mediated by normative beliefs of prevalence estimates, friends' drug use behavior, perceived friends' encouragement to use, and attitudes toward the behavior.

A model for incomplete longitudinal multivariate ordinal data.

In studies where multiple outcome items are repeatedly measured over time, missing data often occur. A longitudinal item response theory model is proposed for analysis of multivariate ordinal outcomes that are repeatedly measured. Under the MAR assumption, this model accommodates missing data at any level (missing item at any time point and/or missing time point). It allows for multiple random subject effects and the estimation of item discrimination parameters for the multiple outcome items. The covariates in the model can be at any level. Assuming either a probit or logistic response function, maximum marginal likelihood estimation is described utilizing multidimensional Gauss-Hermite quadrature for integration of the random effects. An iterative Fisher-scoring solution, which provides standard errors for all model parameters, is used. A data set from a longitudinal prevention study is used to motivate the application of the proposed model. In this study, multiple ordinal items of health behavior are repeatedly measured over time. Because of a planned missing design, subjects answered only two-third of all items at a given point.

A mixed-effects regression model for longitudinal multivariate ordinal data.

A mixed-effects item response theory model that allows for three-level multivariate ordinal outcomes and accommodates multiple random subject effects is proposed for analysis of multivariate ordinal outcomes in longitudinal studies. This model allows for the estimation of different item factor loadings (item discrimination parameters) for the multiple outcomes. The covariates in the model do not have to follow the proportional odds assumption and can be at any level. Assuming either a probit or logistic response function, maximum marginal likelihood estimation is proposed utilizing multidimensional Gauss-Hermite quadrature for integration of the random effects. An iterative Fisher scoring solution, which provides standard errors for all model parameters, is used. An analysis of a longitudinal substance use data set, where four items of substance use behavior (cigarette use, alcohol use, marijuana use, and getting drunk or high) are repeatedly measured over time, is used to illustrate application of the proposed model.

Violence prevention among African American adolescent males.

OBJECTIVE: To test psychosocial mediators of the effects of an intervention in reducing the rate of growth of violence among adolescents. METHOD: Five hundred and seventy-one African American adolescent males participated in this randomized trial. Multilevel modeling techniques were used to ascertain both intervention and mediated effects. RESULTS: Intervention significantly reduced rate of growth of violence and 5 social and psychological factors in the treatment group relative to the control group. Four of these social and psychological factors were found to be complete mediators between the intervention and its preventive effects. CONCLUSION: Changing psychological mediating variables is central to reducing youth violence.