Neighborhood factors and survival to old age: The Jackson Heart Study

Few studies have evaluated environmental factors that predict survival to old age. Our study included 913 African American participants in the Jackson Heart Study (JHS) who resided in the tri-county area of the Jackson, MS metropolitan area and were 65-80 years at baseline. Participants were followed from 2000 through 2019 for the outcome of survival to 85 years old. We evaluated each of the following census tract-level measures of the social/physical environment as exposures: socioeconomic status, cohesion, violence, disorder, healthy food stores, residential land use, and walkability. We assessed mediation by physical activity and chronic conditions. As a complementary ecologic analysis, we used census-tract data to examine factors associated with a greater life expectancy. A total of 501 (55%) JHS participants survived to age 85 years or older. Higher social cohesion and greater residential land use were modestly associated with survival to old age (risk difference = 25%, 95% CI: 0-49%; and 4%, 95% CI: 1-7%, respectively). These neighborhood effects were modestly mediated through leisure time physical activity; additionally, social cohesion was mediated through home and yard activity. In our ecologic analysis, a greater percentage of homeowners and a greater proportion of people living in partnered families were associated with higher census-tract level life expectancy. African American older adults living in residential neighborhoods or neighborhoods with high social cohesion were more likely to survive to old age.

Heritability of mortality in response to a natural pancreas disease (SPDV) challenge in Atlantic salmon, Salmo salar L., post-smolts on a West of Ireland sea site

Pancreas disease (PD) is an economically important disease of European farmed Atlantic salmon. It can cause significant losses because of morbidity, mortality and reduced production. The disease is caused by an alphavirus, known as salmon PD virus (SPDV) or salmonid alphavirus subtype 1 in Ireland. To examine whether it is possible to improve the natural resistance of Atlantic salmon to SPDV by selective breeding, 6000 genotyped, tagged, pedigreed fish from 150 full-sib families were exposed to a natural challenge during 2005 in a sea cage on a commercial salmon farm in the West of Ireland. Histopathological and serological examination was performed weekly on a proportion of all moribund fish to determine the onset of the infection and the likely cause of death. Heritabilities and genetic correlations are presented for resistance to a natural PD challenge and smolt input weight. The results indicate that the susceptibility of salmon to SPDV could be reduced by selective breeding based on the survival in a natural challenge to the virus.

Improving paediatric diabetes care

The authors review the management of paediatric patients in diabetic ketoacidosis. Paying particular attention to the pathophysiology of the illness and nursing documentation, they have developed a new diabetic ketoacidosis flow chart to improve nursing care.

Influence of alteration in preload on the pattern of left ventricular diastolic filling as assessed by Doppler echocardiography in humans

We examined the influence of alterations in preload on pulsed Doppler indexes of left ventricular diastolic function in 50 patients including 12 without cardiovascular disease, 29 with coronary artery disease, and nine with critical aortic stenosis. Micromanometer left ventricular pressure was recorded simultaneously with pulsed Doppler echocardiography of left ventricular inflow and M-mode echocardiography of left ventricular diameter. Chamber stiffness constants, kd and kv, were obtained from the diastolic pressure-diameter and pressure-volume relations, respectively. Relaxation was measured by the isovolumic relaxation time constants, TL and TD, derived from the exponential left ventricular pressure decay and maximum negative dP/dt. In 41 patients after nitroglycerin treatment, left ventricular end-diastolic pressure decreased from 18 +/- 5 to 13 +/- 4 mm Hg (p less than 0.001). The ratio of peak early to peak atrial filling velocities and time-velocity integral ratios decreased from 1.08 +/- 0.57 to 0.90 +/- 0.42 (p less than 0.001) and from 1.77 +/- 0.95 to 1.41 +/- 0.71 (p less than 0.001), respectively. The peak early filling velocity and time-velocity integral decreased from 56.1 +/- 15.7 to 49.9 +/- 14.5 cm/sec (p less than 0.001) and from 7.9 +/- 2.7 to 6.8 +/- 2.8 cm (p less than 0.001), respectively. Relaxation (TL, TD, and maximum negative dP/dt) and chamber stiffness (kd and kv) were not impaired after nitroglycerin administration. In 48 patients after ventriculography, left ventricular end-diastolic pressure increased from 18 +/- 6 to 22 +/- 8 mm Hg (p less than 0.001). The peak early and peak atrial filling velocities increased from 57.4 +/- 15.2 to 68.3 +/- 19.7 cm/sec (p less than 0.001) and from 61.0 +/- 22.7 to 69.4 +/- 23.2 cm/sec (p less than 0.01), respectively. As a result, the ratio of peak early to peak atrial filling velocity was unchanged. However, in the aortic stenosis group, the ratio of peak early to peak atrial filling velocity increased from 0.95 +/- 0.64 to 1.10 +/- 0.72 (p less than 0.02). Relaxation and chamber stiffness were unchanged. Thus, a reduction or increase in preload may induce a diastolic filling pattern that mimics or masks diastolic dysfunction, respectively. Preload conditions need to be accounted for when the status of diastolic function is extrapolated from the pulsed Doppler mitral inflow velocity profile.

Left ventricular diastolic function: comparison of pulsed Doppler echocardiographic and hemodynamic indexes in subjects with and without coronary artery disease

To evaluate the influence of left ventricular chamber stiffness and relaxation on Doppler echocardiographic indexes of diastolic function, 35 patients (mean age 60 +/- 12 years) were examined; 24 had coronary artery disease and 11 (Group I) had no cardiovascular disease. Micromanometer left ventricular pressure was recorded simultaneously with Doppler echocardiograms of mitral valve inflow and M-mode echocardiograms of left ventricular diameter. The chamber stiffness constant (k) was derived from the pressure-diameter relation. Relaxation was assessed by the isovolumic relaxation time constant (tau) derived from the exponential left ventricular pressure decay. The patients with coronary artery disease were classified into two groups on the basis of complete (Group II; n = 10) and incomplete (Group III; n = 14) relaxation. In Group I (no coronary disease), significant correlations were demonstrated between the chamber stiffness constant and the peak early filling velocity (r = 0.73; p less than 0.02), peak early to atrial filling velocity ratio (r = 0.82; p less than 0.005), atrial time-velocity integral (r = -0.73; p less than 0.02), early to atrial time-velocity integral ratio (r = 0.70; p less than 0.05), percent atrial contribution to filling (r = -0.64; p less than 0.05) and one-half filling fraction (r = 0.73; p less than 0.02). In Group II (coronary disease with complete relaxation), the chamber stiffness constant correlated with peak early filling velocity (r = 0.68; p less than 0.05), early filling time-velocity integral (r = 0.65; p less than 0.05) and early to atrial time-velocity integral ratio (r = 0.74; p less than 0.02). No correlations between k and Doppler indexes were found in Group III (coronary disease with incomplete relaxation). However, Group III demonstrated significant correlations between tau and the peak early filling velocity (r = -0.71; p less than 0.005), percent atrial contribution to filling (r = 0.56; p less than 0.05) and mean acceleration rate of early filling (r = -0.79; p less than 0.002). Thus, in subjects with normal relaxation, increasing chamber stiffness was associated with an enhanced peak early filling velocity and volume and decreased filling during atrial systole. This finding differs strikingly from the proposed influence of chamber stiffness on diastolic filling postulated by several researchers.(ABSTRACT TRUNCATED AT 400 WORDS)