Tufts University

About: Tufts University is a education organization based out in Medford, Massachusetts, United States. It is known for research contribution in the topics: Population & Medicine. The organization has 32800 authors who have published 66881 publications receiving 3451152 citations. The organization is also known as: Tufts College & Universitatis Tuftensis.

Equilibrium parity-violating current in a magnetic field

Abstract: It is argued that if the Hamiltonian of a system of charged fermions does not conserve parity, then an equilibrium electric current parallel to $\stackrel{\ensuremath{\rightarrow}}{\mathrm{B}}$ can develop in such a system in an external magnetic field $\stackrel{\ensuremath{\rightarrow}}{\mathrm{B}}$. The equilibrium current is calculated (i) for noninteracting left-handed massless fermions and (ii) for a system of massive particles with a Fermitype parity-violating interaction. In the first case a nonzero current is found, while in the second case the current vanishes in the lowest order of perturbation theory. The physical reason for the cancellation of the current in the second case is not clear and one cannot rule out the possibility that a nonzero current appears in other models.

The unreliability of individual physician "report cards" for assessing the costs and quality of care of a chronic disease.

Abstract: ContextPhysician profiling is widely used by many health care systems, but little is known about the reliability of commonly used profiling systems.ObjectivesTo determine the reliability of a set of physician performance measures for diabetes care, one of the most common conditions in medical practice, and to examine whether physicians could substantially improve their profiles by preferential patient selection.Design and SettingCohort study performed from 1990 to 1993 at 3 geographically and organizationally diverse sites, including a large staff-model health maintenance organization, an urban university teaching clinic, and a group of private-practice physicians in an urban area.ParticipantsA total of 3642 patients with type 2 diabetes cared for by 232 different physicians.Main Outcome MeasuresPhysician profiles for their patients' hospitalization and clinic visit rates, total laboratory resource utilization rate and level of glycemic control by average hemoglobin A1c level with and without detailed case-mix adjustment.ResultsFor profiles based on hospitalization rates, visit rates, laboratory utilization rates, and glycemic control, 4% or less of the overall variance was attributable to differences in physician practice and the reliability of the median physician's case-mix–adjusted profile was never better than 0.40. At this low level of physician effect, a physician would need to have more than 100 patients with diabetes in a panel for profiles to have a reliability of 0.80 or better (while more than 90% of all primary care physicians at the health maintenance organization had fewer than 60 patients with diabetes). For profiles of glycemic control, high outlier physicians could dramatically improve their physician profile simply by pruning from their panel the 1 to 3 patients with the highest hemoglobin A1clevels during the prior year. This advantage from gaming could not be prevented by even detailed case-mix adjustment.ConclusionsPhysician "report cards" for diabetes, one of the highest-prevalence conditions in medical practice, were unable to detect reliably true practice differences within the 3 sites studied. Use of individual physician profiles may foster an environment in which physicians can most easily avoid being penalized by avoiding or deselecting patients with high prior cost, poor adherence, or response to treatments.

Variable expression of the estrogen receptor in normal and atherosclerotic coronary arteries of premenopausal women

Abstract: BACKGROUNDThe relative absence of coronary atherosclerosis in premenopausal women has been established. Estrogen is presumed to play a role in the protection of coronary arteries from atherosclerosis, and part of this protective effect appears to be mediated by amelioration of serum lipid profiles. However, all of the atheroprotective effect of estrogen is not explained by alteration of serum lipids. In this study, we attempt to identify evidence of estrogen receptors in coronary artery specimens of female patients and in human vascular smooth muscle cells.METHODS AND RESULTSPostmortem coronary artery specimens were obtained from premenopausal (n = 18) and postmenopausal (n = 22) women who died with significant coronary artery disease (n = 19) and from noncardiac causes with normal coronary arteries (n = 21). Sections were examined for evidence of estrogen receptor expression using a monoclonal antibody stain. Radioligand binding assays for estrogen receptors were performed on human vascular smooth muscle...

Expression cloning and characterization of the canine parietal cell gastrin receptor.

Abstract: Gastrin is an important stimulant of acid secretion by gastric parietal cells and is structurally related to the peptide hormone cholecystokinin (CCK) The pharmacologic properties of the parietal cell gastrin receptor are very similar to the predominant CCK receptor in the brain, CCK-B Neither the gastrin nor the CCK-B receptor have been cloned thus far, making it difficult to resolve whether these two receptors are distinct We have isolated a clone encoding the canine gastrin receptor by screening a parietal cell cDNA expression library using a radioligand-binding strategy Nucleotide sequence analysis revealed an open reading frame encoding a 453-amino acid protein with seven putative hydrophobic transmembrane domains and significant homology with members of the beta-adrenergic family of G protein-coupled receptors The expressed recombinant receptor shows the same binding specificity for gastrin/CCK agonists and antagonists as the canine parietal cell receptor Gastrin-stimulated phosphatidylinositol hydrolysis and intracellular Ca2+ mobilization in COS-7 cells expressing the cloned receptor suggest second-messenger signaling through phospholipase C Affinity labeling of the expressed receptor in COS-7 cells revealed a protein identical in size to the native parietal cell receptor Gastrin receptor transcripts were identified by high-stringency RNA blot analysis in both parietal cells and cerebral cortex, suggesting that the gastrin and CCK-B receptors are either highly homologous or identical