Mohammad H. Rahbar

Autism spectrum disorder prevalence and proximity to industrial facilities releasing arsenic, lead or mercury

Prenatal and perinatal exposures to air pollutants have been shown to adversely affect birth outcomes in offspring and may contribute to prevalence of autism spectrum disorder (ASD). For this ecologic study, we evaluated the association between ASD prevalence, at the census tract level, and proximity of tract centroids to the closest industrial facilities releasing arsenic, lead or mercury during the 1990s. We used 2000 to 2008 surveillance data from five sites of the Autism and Developmental Disabilities Monitoring (ADDM) network and 2000 census data to estimate prevalence. Multi-level negative binomial regression models were used to test associations between ASD prevalence and proximity to industrial facilities in existence from 1991 to 1999 according to the US Environmental Protection Agency Toxics Release Inventory (USEPA-TRI). Data for 2489 census tracts showed that after adjustment for demographic and socio-economic area-based characteristics, ASD prevalence was higher in census tracts located in the closest 10th percentile compared of distance to those in the furthest 50th percentile (adjusted RR=1.27, 95% CI: (1.00, 1.61), P=0.049). The findings observed in this study are suggestive of the association between urban residential proximity to industrial facilities emitting air pollutants and higher ASD prevalence.

Clinical gestalt and the prediction of massive transfusion after trauma.

INTRODUCTIONnEarly recognition and treatment of trauma patients requiring massive transfusion (MT) has been shown to reduce mortality. While many risk factors predicting MT have been demonstrated, there is no universally accepted method or algorithm to identify these patients. We hypothesised that even among experienced trauma surgeons, the clinical gestalt of identifying patients who will require MT is unreliable.nnnMETHODSnTransfusion and mortality outcomes after trauma were observed at 10 U.S. Level-1 trauma centres in patients who survived ≥ 30 min after admission and received ≥ 1 unit of RBC within 6h of arrival. Subjects who received ≥ 10 units within 24h of admission were classified as MT patients. Trauma surgeons were asked the clinical gestalt question Is the patient likely to be massively transfused? 10 min after the patients arrival. The performance of clinical gestalt to predict MT was assessed using chi-square tests and ROC analysis to compare gestalt to previously described scoring systems.nnnRESULTSnOf the 1245 patients enrolled, 966 met inclusion criteria and 221 (23%) patients received MT. 415 (43%) were predicted to have a MT and 551(57%) were predicted to not have MT. Patients predicted to have MT were younger, more often sustained penetrating trauma, had higher ISS scores, higher heart rates, and lower systolic blood pressures (all p<0.05). Gestalt sensitivity was 65.6% and specificity was 63.8%. PPV and NPV were 34.9% and 86.2% respectively.nnnCONCLUSIONnData from this large multicenter trial demonstrates that predicting the need for MT continues to be a challenge. Because of the increased mortality associated with delayed therapy, a more reliable algorithm is needed to identify and treat these severely injured patients earlier.

Systematic Review and Meta-Analysis of Bone Marrow–Derived Mononuclear Cells in Animal Models of Ischemic Stroke

Background and Purpose— Bone marrow–derived mononuclear cells (BMMNCs) offer the promise of augmenting poststroke recovery. There is mounting evidence of safety and efficacy of BMMNCs from preclinical studies of ischemic stroke; however, their pooled effects have not been described. Methods— Using Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines, we conducted a systematic review of preclinical literature for intravenous use of BMMNCs followed by meta-analyses of histological and behavioral outcomes. Studies were selected based on predefined criteria. Data were abstracted by 2 independent investigators. After quality assessment, the pooled effects were generated using mixed-effect models. Impact of possible biases on estimated effect size was evaluated. Results— Standardized mean difference and 95% confidence interval for reduction in lesion volume was significantly beneficial for BMMNC treatment (standardized mean difference: −3.3; 95% confidence interval, −4.3 to −2.3). n=113 each for BMMNC and controls. BMMNC-treated animals (n=161) also had improved function measured by cylinder test (standardized mean difference: −2.4; 95% confidence interval, −3.1 to −1.6), as compared with controls (n=205). A trend for benefit was observed for adhesive removal test and neurological deficit score. Study quality score (median: 6; Q1–Q3: 5–7) was correlated with year of publication. There was funnel plot asymmetry; however, the pooled effects were robust to the correction of this bias and remained significant in favor of BMMNC treatment. Conclusions— BMMNCs demonstrate beneficial effects across histological and behavioral outcomes in animal ischemic stroke models. Although study quality has improved over time, considerable degree of heterogeneity calls for standardization in the conduct and reporting of experimentation.

Acute splenic responses in patients with ischemic stroke and intracerebral hemorrhage

Animal models provide evidence of spleen mediated post-stroke activation of the peripheral immune system. Translation of these findings to stroke patients requires estimation of pre-stroke spleen volume along with quantification of its day-to-day variation. We enrolled a cohort of 158 healthy volunteers and measured their spleen volume over the course of five consecutive days. We also enrolled a concurrent cohort of 158 stroke patients, measured initial spleen volume within 24u2009h of stroke symptom onset followed by daily assessments. Blood samples for cytokine analysis were collected from a subset of patients. Using data from healthy volunteers, we fit longitudinal quantile regression models to construct gender and body surface area based normograms of spleen volume. We quantified day-to-day variation and defined splenic contraction. Based on our criteria, approximately 40% of stroke patients experienced substantial post-stroke reduction in splenic volume. African Americans, older patients, and patients with past history of stroke have significantly higher odds of post-stroke splenic contraction. All measured cytokine levels were elevated in patients with splenic contraction, with significant differences for interferon gamma, interleukin 6, 10, 12, and 13. Our work provides reference standards for further work, validation of pre-clinical findings, and characterization of patients with post-stroke splenic contraction.

Concentration of Lead, Mercury, Cadmium, Aluminum, Arsenic and Manganese in Umbilical Cord Blood of Jamaican Newborns

The objective of this study was to characterize the concentrations of lead, mercury, cadmium, aluminum, and manganese in umbilical cord blood of Jamaican newborns and to explore the possible association between concentrations of these elements and certain birth outcomes. Based on data from 100 pregnant mothers and their 100 newborns who were enrolled from Jamaica in 2011, the arithmetic mean (standard deviation) concentrations of cord blood lead, mercury, aluminum, and manganese were 0.8 (1.3 μg/dL), 4.4 (2.4 μg/L), 10.9 (9.2 μg/L), and 43.7 (17.7 μg/L), respectively. In univariable General Linear Models, the geometric mean cord blood aluminum concentration was higher for children whose mothers had completed their education up to high school compared to those whose mothers had any education beyond high school (12.2 μg/L vs. 6.4 μg/L; p < 0.01). After controlling for maternal education level and socio-economic status (through ownership of a family car), the cord blood lead concentration was significantly associated with head circumference (adjusted p < 0.01). Our results not only provide levels of arsenic and the aforementioned metals in cord blood that could serve as a reference for the Jamaican population, but also replicate previously reported significant associations between cord blood lead concentrations and head circumference at birth in other populations.

Autism spectrum disorder prevalence and associations with air concentrations of lead, mercury, and arsenic

Lead, mercury, and arsenic are neurotoxicants with known effects on neurodevelopment. Autism spectrum disorder (ASD) is a neurodevelopmental disorder apparent by early childhood. Using data on 4486 children with ASD residing in 2489 census tracts in five sites of the Centers for Disease Control and Prevention’s Autism and Developmental Disabilities Monitoring (ADDM) Network, we used multi-level negative binomial models to investigate if ambient lead, mercury, and arsenic concentrations, as measured by the US Environmental Protection Agency National-Scale Air Toxics Assessment (EPA-NATA), were associated with ASD prevalence. In unadjusted analyses, ambient metal concentrations were negatively associated with ASD prevalence. After adjusting for confounding factors, tracts with air concentrations of lead in the highest quartile had significantly higher ASD prevalence than tracts with lead concentrations in the lowest quartile (prevalence ratio (PR)u2009=u20091.36; 95xa0% CI: 1.18, 1.57). In addition, tracts with mercury concentrations above the 75th percentile (>1.7xa0ng/m3) and arsenic concentrations below the 75th percentile (≤0.13xa0ng/m3) had a significantly higher ASD prevalence (adjusted RRu2009=u20091.20; 95xa0% CI: 1.03, 1.40) compared to tracts with arsenic, lead, and mercury concentrations below the 75th percentile. Our results suggest a possible association between ambient lead concentrations and ASD prevalence and demonstrate that exposure to multiple metals may have synergistic effects on ASD prevalence.

Prospective, open-label safety study of intravenous recombinant tissue plasminogen activator in wake-up stroke.

It is estimated that one of four ischemic strokes are noticed upon awakening and are not candidates for intravenous recombinant tissue plasminogen activator (rtPA) because their symptoms are >3 hours from last seen normal (LSN). We tested the safety of rtPA in a multicenter, single‐arm, prospective, open‐label study (NCT01183533) in patients with wake‐up stroke (WUS).

Early depression screening is feasible in hospitalized stroke patients.

Background and Purpose Post-stroke depression (PSD) is common but is not routinely assessed for in hospitalized patients. As a Comprehensive Stroke Center, we screen all stroke inpatients for depression, though the feasibility of early screening has not been established. We assessed the hypothesis that early depression screening in stroke patients is feasible. We also explored patient level factors associated with being screened for PSD and the presence of early PSD. Methods The medical records of all patients admitted with ischemic stroke (IS) or intracerebral hemorrhage (ICH) between 01/02/13 and 15/04/13 were reviewed. A depression screen, modified from the Patient Health Questionnaire-9, was administered (maximum score 27, higher scores indicating worse depression). Patients were eligible if they did not have a medical condition precluding screening. Feasibility was defined as screening 75% of all eligible patients. Results Of 303 IS and ICH inpatients, 70% (211) were eligible for screening, and 75% (158) of all eligible patients were screened. More than one-third of all patients screened positive for depression (score > 4). Women (OR 2.06, 95% CI 1.06–4.01) and younger patients (OR 0.97, 95% CI 0.96–0.99) were more likely to screen positive. Screening positive was not associated with poor discharge/day 7 outcome (mRS > 3; OR 1.45, 95% CI 0.74–2.83). Conclusions Screening stroke inpatients for depression is feasible and early depression after stroke is common. Women and younger patients are more likely to experience early PSD. Our results provide preliminary evidence supporting continued screening for depression in hospitalized stroke patients.

Evaluating Academic Scientists Collaborating in Team-Based Research: A Proposed Framework

Criteria for evaluating faculty are traditionally based on a triad of scholarship, teaching, and service. Research scholarship is often measured by first or senior authorship on peer-reviewed scientific publications and being principal investigator on extramural grants. Yet scientific innovation increasingly requires collective rather than individual creativity, which traditional measures of achievement were not designed to capture and, thus, devalue. The authors propose a simple, flexible framework for evaluating team scientists that includes both quantitative and qualitative assessments. An approach for documenting contributions of team scientists in team-based scholarship, nontraditional education, and specialized service activities is also outlined. Although biostatisticians are used for illustration, the approach is generalizable to team scientists in other disciplines.The authors offer three key recommendations to members of institutional promotion committees, department chairs, and others evaluating team scientists. First, contributions to team-based scholarship and specialized contributions to education and service need to be assessed and given appropriate and substantial weight. Second, evaluations must be founded on well-articulated criteria for assessing the stature and accomplishments of team scientists. Finally, mechanisms for collecting evaluative data must be developed and implemented at the institutional level. Without these three essentials, contributions of team scientists will continue to be undervalued in the academic environment.

Blood Lead Concentrations in Jamaican Children with and without Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder manifesting by early childhood. Lead is a toxic metal shown to cause neurodevelopmental disorders in children. Several studies have investigated the possible association between exposure to lead and ASD, but their findings are conflicting. Using data from 100 ASD cases (2–8 years of age) and their age- and sex-matched typically developing controls, we investigated the association between blood lead concentrations (BLC) and ASD in Jamaican children. We administered a questionnaire to assess demographic and socioeconomic information as well as exposure to potential lead sources. We used General Linear Models (GLM) to assess the association of BLC with ASD status as well as with sources of exposure to lead. In univariable GLM, we found a significant difference between geometric mean blood lead concentrations of ASD cases and controls (2.25 μg/dL cases vs. 2.73 μg/dL controls, p < 0.05). However, after controlling for potential confounders, there were no significant differences between adjusted geometric mean blood lead concentrations of ASD cases and controls (2.55 μg/dL vs. 2.72 μg/dL, p = 0.64). Our results do not support an association between BLC and ASD in Jamaican children. We have identified significant confounders when assessing an association between ASD and BLC.