Rakesh Mandal

Quantitative magnetic resonance imaging of hepatic steatosis: Validation in ex vivo human livers.

Emerging magnetic resonance imaging (MRI) biomarkers of hepatic steatosis have demonstrated tremendous promise for accurate quantification of hepatic triglyceride concentration. These methods quantify the proton density fat‐fraction (PDFF), which reflects the concentration of triglycerides in tissue. Previous in vivo studies have compared MRI‐PDFF with histologic steatosis grading for assessment of hepatic steatosis. However, the correlation of MRI‐PDFF with the underlying hepatic triglyceride content remained unknown. The aim of this ex vivo study was to validate the accuracy of MRI‐PDFF as an imaging biomarker of hepatic steatosis. Using ex vivo human livers, we compared MRI‐PDFF with magnetic resonance spectroscopy‐PDFF (MRS‐PDFF), biochemical triglyceride extraction, and histology as three independent reference standards. A secondary aim was to compare the precision of MRI‐PDFF relative to biopsy for the quantification of hepatic steatosis. MRI‐PDFF was prospectively performed at 1.5 Tesla in 13 explanted human livers. We performed colocalized paired evaluation of liver fat content in all nine Couinaud segments using single‐voxel MRS‐PDFF (n = 117) and tissue wedges for biochemical triglyceride extraction (n = 117), and five core biopsies performed in each segment for histologic grading (n = 585). Accuracy of MRI‐PDFF was assessed through linear regression with MRS‐PDFF, triglyceride extraction, and histology. Intraobserver agreement, interobserver agreement, and repeatability of MRI‐PDFF and histologic grading were assessed through Bland‐Altman analyses. MRI‐PDFF showed an excellent correlation with MRS‐PDFF (r = 0.984, confidence interval 0.978‐0.989) and strong correlation with histology (r = 0.850, confidence interval 0.791‐0.894) and triglyceride extraction (r = 0.871, confidence interval 0.818‐0.909). Intraobserver agreement, interobserver agreement, and repeatability showed a significantly smaller variance for MRI‐PDFF than for histologic steatosis grading (all P < 0.001). Conclusion: MRI‐PDFF is an accurate, precise, and reader‐independent noninvasive imaging biomarker of liver triglyceride content, capable of steatosis quantification over the entire liver. (Hepatology 2015;62:1444–1455)

Top-down proteomics with mass spectrometry imaging: a pilot study towards discovery of biomarkers for neurodevelopmental disorders.

In the developing mammalian brain, inhibition of NMDA receptor can induce widespread neuroapoptosis, inhibit neurogenesis and cause impairment of learning and memory. Although some mechanistic insights into adverse neurological actions of these NMDA receptor antagonists exist, our understanding of the full spectrum of developmental events affected by early exposure to these chemical agents in the brain is still limited. Here we attempt to gain insights into the impact of pharmacologically induced excitatory/inhibitory imbalance in infancy on the brain proteome using mass spectrometric imaging (MSI). Our goal was to study changes in protein expression in postnatal day 10 (P10) rat brains following neonatal exposure to the NMDA receptor antagonist dizocilpine (MK801). Analysis of rat brains exposed to vehicle or MK801 and comparison of their MALDI MS images revealed differential relative abundances of several proteins. We then identified these markers such as ubiquitin, purkinje cell protein 4 (PEP-19), cytochrome c oxidase subunits and calmodulin, by a combination of reversed-phase (RP) HPLC fractionation and top-down tandem MS platform. More in-depth large scale study along with validation experiments will be carried out in the future. Overall, our findings indicate that a brief neonatal exposure to a compound that alters excitatory/inhibitory balance in the brain has a long term effect on protein expression patterns during subsequent development, highlighting the utility of MALDI-MSI as a discovery tool for potential biomarkers.

Impact of Chemotherapy for Childhood Leukemia on Brain Morphology and Function

Objective Using multidisciplinary treatment modalities the majority of children with cancer can be cured but we are increasingly faced with therapy-related toxicities. We studied brain morphology and neurocognitive functions in adolescent and young adult survivors of childhood acute, low and standard risk lymphoblastic leukemia (ALL), which was successfully treated with chemotherapy. We expected that intravenous and intrathecal chemotherapy administered in childhood will affect grey matter structures, including hippocampus and olfactory bulbs, areas where postnatal neurogenesis is ongoing. Methods We examined 27 ALL-survivors and 27 age-matched healthy controls, ages 15–22 years. ALL-survivors developed disease prior to their 11th birthday without central nervous system involvement, were treated with intrathecal and systemic chemotherapy and received no radiation. Volumes of grey, white matter and olfactory bulbs were measured on T1 and T2 magnetic resonance images manually, using FIRST (FMRIB’s integrated Registration and Segmentation Tool) and voxel-based morphometry (VBM). Memory, executive functions, attention, intelligence and olfaction were assessed. Results Mean volumes of left hippocampus, amygdala, thalamus and nucleus accumbens were smaller in the ALL group. VBM analysis revealed significantly smaller volumes of the left calcarine gyrus, both lingual gyri and the left precuneus. DTI data analysis provided no evidence for white matter pathology. Lower scores in hippocampus-dependent memory were measured in ALL-subjects, while lower figural memory correlated with smaller hippocampal volumes. Interpretation Findings demonstrate that childhood ALL, treated with chemotherapy, is associated with smaller grey matter volumes of neocortical and subcortical grey matter and lower hippocampal memory performance in adolescence and adulthood.

Disparities in chronic myeloid leukemia survival by age, gender, and ethnicity in pre- and post-imatinib eras in the US.

Abstract Background. Since May 2001, imatinib mesylate has become the first-line therapy for chronic myeloid leukemia (CML) but the survival pattern by age, sex, and ethnicity is not clear. Material and methods. We analyzed the Surveillance, Epidemiology, and End Results (SEER*Stat) database to compare survival rates in CML among Caucasians, African-Americans (AA), and other races, and also within each race to see survival differences from the pre-imatinib (1973–2000) to post-imatinib eras (2002–2008). We used Z-tests in SEER*Stat to compare relative survival rates categorized by race, gender, and age groups (all ages, < 50, 50+ years). Results. The three-year relative survival rates among Caucasians, AA, and other races in the pre-imatinib era were 44.9 ± 0.6%, 46.8 ± 1.8%, and 48.0 ± 2.2%, respectively, and in the post-imatinib era 64.4 ± 0.8%, 67.3 ± 2.4%, and 69.6 ± 1.6%, respectively. The relative survival increased from the pre-to post-imatinib era for all ethnic groups. In the post-imatinib era, three-year relative survival rates among young AA women were significantly lower (Z-value = −2.54, p = 0.011) than young Caucasian women, 80.5 ± 4.5% (n = 105) vs. 90.3 ± 1.4% (n = 589). Conclusions. The relative survival rates of CML patients have improved in the post-imatinib era. However, the improvement in survival rates has been modest in this population-based data compared to those reported from randomized trials. Improvement in survival among older patients is lower than in younger patients. Young (<50 years) AA women with CML had lower relative survival rates compared to young Caucasian women in the post-imatinib era.

Estrogen receptor positive breast cancers and their association with environmental factors

BackgroundEpidemiological studies to assess risk factors for breast cancer often do not differentiate between different types of breast cancers. We applied a general linear model to determine whether data from the Surveillance, Epidemiology, and End Results Program on annual county level age-adjusted incidence rates of breast cancer with and without estrogen receptors (ER+ and ER-) were associated with environmental pollutants.ResultsOur final model explained approximately 38% of the variation in the rate of ER+ breast cancer. In contrast, we were only able to explain 14% of the variation in the rate of ER- breast cancer with the same set of environmental variables. Only ER+ breast cancers were positively associated with the EPAs estimated risk of cancer based on toxic air emissions and the proportion of agricultural land in a county. Meteorological variables, including short wave radiation, temperature, precipitation, and water vapor pressure, were also significantly associated with the rate of ER+ breast cancer, after controlling for age, race, premature mortality from heart disease, and unemployment rate.ConclusionsOur findings were consistent with what we expected, given the fact that many of the commonly used pesticides and air pollutants included in the EPA cancer risk score are classified as endocrine disruptors and ER+ breast cancers respond more strongly to estrogen than ER- breast cancers. The findings of this study suggest that ER+ and ER- breast cancers have different risk factors, which should be taken into consideration in future studies that seek to understand environmental risk factors for breast cancer.

Organ weight changes associated with body mass index determined from a medical autopsy population.

ContextExisting organ weight charts used by pathologists for patients undergoing medical autopsy do not illustrate the effect of obesity and age on organ weights among a general population of older individuals with multiple comorbidities. MethodsWe retrospectively reviewed 300 medical autopsy reports to extract data to analyze the effect of obesity and age on organ weights. ResultsIn both men and women, there were statistically significant increases in organ weights with body mass index (BMI) but decreases with age for liver, spleen, and kidneys. In men, increased age was associated with increased left ventricular wall thickness, whereas increased BMI was associated with increased heart weight. In women, only BMI was associated with changes in all 3 anatomic cardiac parameters (heart weight and thickness of the right and left ventricular walls). Age effects were not observed for heart parameters in women. Thyroid weight increased with BMI in men but not in women. ConclusionsThe findings demonstrate changes in organ weights/sizes with obesity and age in a population of patients with multiple comorbidities. The differential effects of age and BMI on the heart between men and women raise the possibility that increased BMI in women may have a greater impact on cardiovascular causes of death than that in men.

Bilateral acute necrosis of the globi pallidi and rhabdomyolysis due to combined methadone and benzodiazepine toxicity

AbstractMethadone continues to be a widely used maintenance therapy for opiate dependence. However, methadone-related deaths have been reported frequently for over 4 decades now. Anoxic brain injury with pulmonary edema secondary to respiratory depression is the recognized mechanism of methadone death, although pathological intracranial findings are rarely described in methadone deaths. A selective area of brain injury has never been reported with methadone use. We present a case of a 23-year-old man who had acute necrosis of the bilateral globi pallidi in the brain and systemic rhabdomyolysis after ingesting methadone and nasally insufflating alprazolam. We also present a review of the literature on deaths following opioid use and associated brain injury.

Eosinophilic Coronary Periarteritis with Arterial Dissection: The Mast Cell Hypothesis.

A subset of coronary arterial dissections is associated with eosinophilic coronary periarteritis (ECPA); however, the pathogenesis of the process remains unclear. Mast cells normally reside in coronary arterial adventitia and are known mediators of eosinophilic inflammatory conditions such as type I hypersensitivity reactions. We report two cases in which coronary arterial dissection with ECPA was detected at autopsy. Tryptase, CD68, CD4, CD8, and CD1a immunohistochemical staining was performed to better characterize inflammation. While eosinophils represented a prominent periadventitial inflammatory cell, there were slightly more lymphocytes: CD4/CD8 ratios were within expected reference ranges. There were moderate numbers of macrophages, and few neutrophils or dendritic cells. Numbers of mast cells in dissected versus nondissected sections were compared: adventitial mast cell densities were threefold higher in dissected portions and showed a trend toward increased degranulation. These findings suggest that mast cells may play a role in orchestrating inflammation in cases of ECPA.

Quantitative MR Imaging of Hepatic Steatosis: Validation in Ex Vivo Human Livers

Emerging magnetic resonance imaging (MRI) biomarkers of hepatic steatosis have demonstrated tremendous promise for accurate quantification of hepatic triglyceride concentration. These methods quantify the proton density fat‐fraction (PDFF), which reflects the concentration of triglycerides in tissue. Previous in vivo studies have compared MRI‐PDFF with histologic steatosis grading for assessment of hepatic steatosis. However, the correlation of MRI‐PDFF with the underlying hepatic triglyceride content remained unknown. The aim of this ex vivo study was to validate the accuracy of MRI‐PDFF as an imaging biomarker of hepatic steatosis. Using ex vivo human livers, we compared MRI‐PDFF with magnetic resonance spectroscopy‐PDFF (MRS‐PDFF), biochemical triglyceride extraction, and histology as three independent reference standards. A secondary aim was to compare the precision of MRI‐PDFF relative to biopsy for the quantification of hepatic steatosis. MRI‐PDFF was prospectively performed at 1.5 Tesla in 13 explanted human livers. We performed colocalized paired evaluation of liver fat content in all nine Couinaud segments using single‐voxel MRS‐PDFF (n = 117) and tissue wedges for biochemical triglyceride extraction (n = 117), and five core biopsies performed in each segment for histologic grading (n = 585). Accuracy of MRI‐PDFF was assessed through linear regression with MRS‐PDFF, triglyceride extraction, and histology. Intraobserver agreement, interobserver agreement, and repeatability of MRI‐PDFF and histologic grading were assessed through Bland‐Altman analyses. MRI‐PDFF showed an excellent correlation with MRS‐PDFF (r = 0.984, confidence interval 0.978‐0.989) and strong correlation with histology (r = 0.850, confidence interval 0.791‐0.894) and triglyceride extraction (r = 0.871, confidence interval 0.818‐0.909). Intraobserver agreement, interobserver agreement, and repeatability showed a significantly smaller variance for MRI‐PDFF than for histologic steatosis grading (all P < 0.001). Conclusion: MRI‐PDFF is an accurate, precise, and reader‐independent noninvasive imaging biomarker of liver triglyceride content, capable of steatosis quantification over the entire liver. (Hepatology 2015;62:1444–1455)

Survival trends in metastatic bladder cancer in the United States: A population based study

BACKGROUND To evaluate the relative survival rates for patients with metastatic bladder cancer (MBC) over the last two decades in the United States: 1991-2000 and 2001-2010. MATERIALS AND METHODS We used the Surveillance, Epidemiology, and End Results (SEER*Stat) Program to analyze 6-month and 12-month relative survival rates of American Joint Committee on Cancer (AJCC) Stage IV bladder cancer patients included in the SEER database. We used Z-test in the SEER*Stat Program to compare relative survival rates among cohorts of patients categorized by race, gender, and age groups (<60 and ≥ 60 years). RESULTS The dataset comprised 4195 and 7629 patients with AJCC Stage IV bladder cancer in the periods 1991-2000 and 2001-2010, respectively. There were statistically significant decreases in relative survival rates for pooled data across all races (67.8 ± 0.7% in 1991-2000 vs. 64.7 ± 0.5% in 2001-2010, P < 0.01), among Caucasian (CC) and other races (Oth) men + women, among CC and Oth men, and several cohorts among men and 60 + Oth-women when categorized by age. African American patients did not show significant changes in survival. CONCLUSIONS This population-based study shows that decreases in 6-month and 12-month relative survival rates among patients with MBC in 2001-2010 compared to 1991-2000, specifically, more pronounced among CC men and Oth men.