Reactions of hemoglobin with phenylhydrazine: a review of selected aspects.

It is well known that phenylhydrazine induces hemolytic anemia. This is thought to result from the reaction of phenylhydrazine with hemoglobin. The accompanying oxidation of phenylhydrazine leads to the formation of a number of products, including benzene, nitrogen, hydrogen peroxide, superoxide anion and the phenyl radical. The products formed depend critically on the conditions of the experiment, especially the amount of oxygen present. It is now known that oxyhemoglobin and myoglobin react with phenylhydrazine to yield a derivative of hemoglobin containing N-phenylprotoporphyrin in which the heme group is modified. The recent identification of sigma-phenyliron(III) porphyrins in phenylhydrazine-modified metmyoglobin has aided elucidation of the mechanism of hemoglobin modification. Mechanistic schemes are proposed to account for product formation

Validation of a Contour Method Single-Measurement Uncertainty Estimator

This work validates an analytical single-measurement uncertainty estimator for contour method measurement by comparing it with a first-order uncertainty estimate provided by a repeatability study. The validation was performed on five different specimen types. The specimen types cover a range of geometries, materials, and stress conditions that represent typical structural applications. The specimen types include: an aluminum T-section, a stainless steel plate with a dissimilar metal slot-filled weld, a stainless steel forging, a titanium plate with an electron beam slot-filled weld, and a nickel disk forging. For each specimen, the residual stress was measured using the contour method on replicate specimens to assess measurement precision. The uncertainty associated with each contour method measurement was also calculated using a recently published single-measurement uncertainty estimator. Comparisons were then made between the estimated uncertainty and the demonstrated measurement precision. These results show that the single-measurement analytical uncertainty estimate has good correlation with the demonstrated repeatability. The spatial distributions of estimated uncertainty were found to be similar among the conditions evaluated, with the uncertainty relatively constant in the interior and larger along the boundaries of the measurement plane

The androgen receptor drives the sex-specific expression of vascular cell adhesion molecule-1 in endothelial cells but not lipid metabolism genes in monocyte-derived macrophages

Background: Anecdotal evidence suggests that male sex hormones are proatherogenic. We hypothesized that the male sex hormone receptor, the androgen receptor (AR), acts as a molecular switch in sex-specific inflammatory signaling in vascular cells. Materials and methods: AR expression in human umbilical vein endothelial cells (HUVECs), human monocyte-derived macrophages (MDMs) or HeLa cells was modulated by transfection with AR siRNA or human AR cDNA expression vector. Activity and expression levels were measured by luciferase reporter assays, Western blotting or real-time PCR analysis. Results: AR knockdown reduced expression of vascular cell adhesion molecule-1 (VCAM-1) in genetically male HUVECs. Conversely, AR upregulation in genetically female HUVECs induced VCAM-1 expression and increased dihydrotestos-terone-stimulated monocyte adhesion. Co-transfection of an AR expression vector with VCAM-1 or NF-kB-reporter vectors into phenotypically female, AR-negative HeLa cells confirmed AR regulation of VCAM-1 expression as well as AR activation of NF-kB. AR upregulation was not sufficient to increase ICAM-1 levels in female HUVECs or lipoprotein metabolism gene expression in female MDMs, despite AR knockdown limiting expression in their male counterparts. Conclusions: AR acts as a molecular switch to induce VCAM-1 expression. Low AR levels in female HUVECs limit NF-kB/VCAM-1 induction and monocyte adhesion and could contribute to the gender bias in cardiovascular disease. Unidentified factors in female cells limit induction of other proatherogenic genes not primarily regulated by NF-kB. © 2010, by Walter de Gruyter Berlin New York. All rights reserved

C. Stratton Hill, Jr., MD, Oral History Interview, February 17, 2012

Major Topics Covered: MD Anderson history and culture: research innovation Pain management: development of field; first book on; cultural and social factors influencing use of opioidshttps://openworks.mdanderson.org/mchv_interviewsessions/1208/thumbnail.jp

C. Stratton Hill, Jr., MD, Oral History Interview, February 14, 2012

Major Topics Covered: Personal and educational background; faith Research: thyroid cancer; pain management and policyhttps://openworks.mdanderson.org/mchv_interviewsessions/1207/thumbnail.jp

C. Stratton Hill, Jr., MD, Oral History Interview, February 20, 2012

Major Topics Covered: Developing the Ambulatory Care Clinichttps://openworks.mdanderson.org/mchv_interviewsessions/1209/thumbnail.jp

C. Stratton Hill, Jr., MD, Oral History Interview, February 28, 2012

Major Topics Covered: Hospice and MD Anderson The Texas Cancer Council; Texas Cancer Pain Initiativehttps://openworks.mdanderson.org/mchv_interviewsessions/1210/thumbnail.jp

Splitting It Up: The spduration Split-Population Duration Regression Package for Time-Varying Covariates

We present an implementation of split-population duration regression in the spduration (Beger et al., 2017) package for R that allows for time-varying covariates. The statistical model accounts for units that are immune to a certain outcome and are not part of the duration process the researcher is primarily interested in. We provide insights for when immune units exist, that can significantly increase the predictive performance compared to standard duration models. The package includes estimation and several post-estimation methods for split-populationWeibull and log-logistic models. We provide an empirical application to data on military coups