Megakaryocyte interaction with subendothelial extracellular matrix is associated with adhesion, platelet-like shape change, and thromboxane A2 production

We have examined the morphological and secretory behavior of rat and guinea pig megakaryocytes exposed for up to 24 hours to extracellular matrix produced by cultured bovine endothelial cells. By phase-contrast microscopy of living cells and in more detail by scanning electron microscopy, the megakaryocytes showed a nonreversible adherence, an extensive formation of filopodia around the periphery like the rays of the sun, and a tendency toward flattening. These filopodia were generally linear with attenuated tips and were larger than, but resembled the filopodia of, rat or guinea pig platelets exposed to this extracellular matrix. In contrast, isolated megakaryocytes on glass or on uncoated plastic surfaces did not show these responses; adherence, in the face of gentle agitation before fixation, was minimal, with rare filopodia and no flattening. Megakaryocytes that interacted with the extracellular matrix produced significant amounts of thromboxane A2, but this did not occur on uncoated surfaces and could not be attributed to other contaminating cells in the megakaryocyte suspensions. The appearance in megakaryocytes of these typical platelet responses indicates that megakaryocytes acquire the functional capabilities of platelets by the synthesis and assembly of platelet substances and organelles. Thromboxane production by megakaryocytes stimulated by the extracellular matrix is a readily quantifiable measure of this capacity.     

Frequency of attendance at religious services, cardiovascular disease, metabolic risk factors and dietary intake in Americans: an age-stratified exploratory analysis

BACKGROUND: Few data have been published on the association of attendance at religious services with cardiovascular morbidity and dietary and metabolic risk factors in representative samples of populations despite a known inverse association with mortality and smoking. OBJECTIVE: To test the null hypothesis that frequency of attendance at religious services is unrelated to prevalence or levels of cardiovascular disease, dietary and metabolic risk factors. DESIGN: Cross-sectional survey of a large national sample. PARTICIPANTS: American men and women aged 20 years and over with complete data in the Third National Health and Nutrition Examination Survey (N = 14,192). MEASUREMENTS: Self-reported frequency of attendance at religious services, history of doctor-diagnosed diseases, food intake frequency, 24-hour dietary intake, health status, socio-demographic variables and measured serum lipids and body mass index. RESULTS: Weekly attenders were significantly less likely to report stroke, even after adjusting for multiple variables only in African American women OR = 0.35, 95% CI 0.19-0.66, p < 0.01. No association was seen for heart attack or diabetes. Fish intake at least weekly was more common in weekly attenders, significantly so only in African American women (odds ratio 1.24, 95% CI 1.01-1.58, p < 0.05) and in older Mexican American men (odds ratio 2.57, 95% CI 1.45-2.57, p < 0.01). In linear regression analyses, no significant independent associations were seen between attendance frequency and serum lipid levels or dietary intake of energy, or fat in g and % of kcal. CONCLUSION: Hypotheses generated by these analyses are that in African American women stroke is less prevalent and weekly fish intake more prevalent among weekly attenders than others and that there are no significant independent associations of serum lipids, dietary intake, prevalent CHD, or diabetes with frequency of attendance of religious services. Independent testing of these hypotheses in other samples is needed.     

From Papyrus to the Electronic Tablet: A Brief History of the Clinical Medical Record with Lessons for the Digital Age

A major transition is underway in documentation of patient-related data in clinical settings with rapidly accelerating adoption of the electronic health record and electronic medical record. This article examines the history of the development of medical records in the West in order to suggest lessons applicable to the current transition. The first documented major transition in the evolution of the clinical medical record occurred in antiquity, with the development of written case history reports for didactic purposes. Benefiting from Classical and Hellenistic models earlier than physicians in the West, medieval Islamic physicians continued the development of case histories for didactic use. A forerunner of modern medical records first appeared in Paris and Berlin by the early 19th century. Development of the clinical record in America was pioneered in the 19th century in major teaching hospitals. However, a clinical medical record useful for direct patient care in hospital and ambulatory settings was not developed until the 20th century. Several lessons are drawn from the 4000-year history of the medical record that may help physicians improve patient care in the digital age.     

High-density Lipoprotein Cholesterol,Cognitive Function and Mortality in a U.S. National Cohort

Low levels of both high density lipoprotein cholesterol (HDL) and cognitive function are associated with increased mortality risk. HDL plays an important role in brain metabolism. We test the hypotheses that the relative protective effect of high HDL level as related to mortality is greater in persons with impaired cognitive function than in others. Data were analyzed from a longitudinal mortality follow-up study of 4911 American men and women aged 60 years and over examined in 1988-1994 followed an average 8.5 yr. Measurements at baseline included HDL, a short index of cognitive function (SICF), socio-demographics, health status, and self-reported leisure-time physical activity. In proportional hazards regression analysis, no significant interaction of HDL with cognitive function was found (p = 0.08); there was a significant age-SICF interaction. After stratifying by age and adjusting for confounding by multiple variables, independent associations of HDL and SICF score with survival were strongest among the oldest persons. Consistent with its association with HDL, cognitive function and survival, controlling in addition for physical activity reduced the associations. In a nationwide cohort of older Americans, analyses demonstrated a lower risk of death independent of confounders among those high HDL and SICF scores, strongest among the oldest persons.