Race/ethnicity and socioeconomic status (SES) are social categories that capture differential exposure to conditions of life that have health consequences. Race/ethnicity and SES are linked to each ...other, but race matters for health even after SES is considered. This commentary considers the complex ways in which race combines with SES to affect health. There is a need for greater attention to understanding how risks and resources in the social environment are systematically patterned by race, ethnicity and SES, and how they combine to influence cardiovascular disease and other health outcomes. Future research needs to examine how the levels, timing and accumulation of institutional and interpersonal racism combine with other toxic exposures, over the life-course, to influence the onset and course of illness. There is also an urgent need for research that seeks to build the science base that will identify the multilevel interventions that are likely to enhance the health of all, even while they improve the health of disadvantaged groups more rapidly than the rest of the population so that inequities in health can be reduced and ultimately eliminated. We also need sustained research attention to identifying how to build the political support to reduce the large shortfalls in health.
In 1959, Ivar Sperber contrasted bile formation with that of urine and proposed that water flow into the canalicular conduit is in response to an osmotic not a hydrostatic gradient. Early attempts to ...support the hypothesis using a bile acid, sodium taurocholate, and the hormone secretin to stimulate bile flow led to conflicting data and a moratorium on attempts to further develop the initial proposal. However, current data amplifiy the proposal and indicate both paracellular and transcellular water flow into hepatic ductules and the canalicular conduit in response to an osmotic gradient. Also, the need to further modify the initial proposal became apparent with the recognition that bile acid aggregates (micelles) generate lecithin-cholesterol vesicles that contain water unrelated to an osmotic gradient. As part of this development is the recent introduction of the FLAP technique for direct determination of hepatic duct flow and clarification of the role of biomarkers such as mannitol and polyethylene glycol 900. With the new paradigm these biomarkers may prove useful for quantifying paracellular and transcellular water flow, respectively.
It is essential to identify and characterize all the sites for water flow during hepatic bile formation to obtain more precision in evaluating the causes and possible therapeutic approaches to cholestatic syndromes. Updating the Sperber proposal provides a new paradigm that addresses the advances in knowledge that have occurred.
For 130 years, dinosaurs have been divided into two distinct clades-Ornithischia and Saurischia. Here we present a hypothesis for the phylogenetic relationships of the major dinosaurian groups that ...challenges the current consensus concerning early dinosaur evolution and highlights problematic aspects of current cladistic definitions. Our study has found a sister-group relationship between Ornithischia and Theropoda (united in the new clade Ornithoscelida), with Sauropodomorpha and Herrerasauridae (as the redefined Saurischia) forming its monophyletic outgroup. This new tree topology requires redefinition and rediagnosis of Dinosauria and the subsidiary dinosaurian clades. In addition, it forces re-evaluations of early dinosaur cladogenesis and character evolution, suggests that hypercarnivory was acquired independently in herrerasaurids and theropods, and offers an explanation for many of the anatomical features previously regarded as notable convergences between theropods and early ornithischians.
Here is the full report of the 1970 National Fertility Study, a national sample survey for which thousands of women were interviewed who had been married at some time and were of reproductive age ...when they were interviewed. The book assesses the growth in the use of the pill and the IUD, the increasing reliance on contraceptive sterilization, and both the intended and the unwanted fertility of American women.
The volume opens with an introduction to the survey and its methods. Contraceptive practice in 1970 is then compared with data for 1965, and an analysis is supplied of trends since 1955 in the attitudes of Roman Catholics.
Originally published in 1977.
ThePrinceton Legacy Libraryuses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.
Advances in molecular biology identifying the many carrier-mediated organic anion transporters and advances in microscopy that have provided a more detailed anatomy of the canalicular conduit make ...updating the concept of osmotically determined canalicular flow possible. For the most part water flow is not transmembrane but via specific pore proteins in both the hepatocyte and the tight junction. These pores independently regulate the rate at which water flows in response to an osmotic gradient and therefore are determinants of canalicular bile acid concentration. Review of the literature indicates that the initial effect on hepatic bile flow of cholestatic agents such as Thorazine and estradiol 17β-glucuronide are on water flow and not bile salt export pump-mediated bile acid transport and thus provides new approaches to the pathogenesis of drug-induced liver injury. Attaining a micellar concentration of bile acids in the canaliculus is essential to the formation of cholesterol-lecithin vesicles, which mostly occur in the periportal region of the canalicular conduit. The other regions, midcentral and pericentral, may transport lesser amounts of bile acid but augment water flow. Broadening the concept of how hepatic bile flow is initiated, provides new insights into the pathogenesis of canalicular cholestasis.
PDF
