Interplay of genetic and actual lifespans.
Explore the source record for details and available documents.
Biological Evolution↗
Biomedical subjects
H Sayama
Publications and source records attributed to H Sayama.
Symmetry breaking and coarsening in spatially distributed evolutionary processes including sexual reproduction and disruptive selection.
Sexual reproduction presents significant challenges to formal treatment of evolutionary processes. A starting point for systematic treatments of ecological and evolutionary phenomena has been provided by the gene-centered view of evolution which assigns effective fitness to each allele instead of each organism. The gene-centered view can be formalized as a dynamic mean-field approximation applied to genes in reproduction and selection dynamics. We show that the gene-centered view breaks down for symmetry breaking and pattern formation within a population and show that spatial distributions of organisms with local mating neighborhoods in the presence of disruptive selection give rise to such symmetry breaking and pattern formation in the genetic composition of local populations. Global dynamics follows conventional coarsening of systems with nonconserved order parameters. The results have significant implications for the ecology of genetic diversity and species formation.
Alleles↗
Why is the concentration of plasma brain natriuretic peptide in elderly inpatients greater than normal?
BACKGROUND: Higher than normal levels of plasma brain natriuretic peptide (BNP) are often found in elderly patients without overt heart failure. OBJECTIVE: To investigate the relationships between echocardiographic findings and levels of BNP in inpatients undergoing rehabilitation. METHODS: Ejection fraction, early-to-atrial peak transmitral velocity ratio (EAR) and left ventricular mass index were calculated. The patients were 34 men and 83 women, aged 83.4 +/- 0.8 years (mean +/- SEM). RESULTS: The average BNP was 3.5 times higher than the normal range. Age of and BNP level in patients with mild renal dysfunction were significantly greater than age of and BNP level in those with normal renal function. BNP level in patients with left ventricular hypertrophy (LVH) was higher than that in patients without LVH, and there was a positive correlation between left ventricular mass index and BNP level. However, there was no difference between BNP levels of patients with ejection fraction < 50% and > or = 50% (n = 27 versus 90, ejection fractions 40 versus 64%, BNP levels 22.6 +/- 4.0 versus 17.5 +/- 1.6 pmol/l). Moreover, even elderly inpatients without LVH, without cardiovascular diseases, with sinus rhythm, with normal renal function, and with normal left ventricle systolic function had BNP levels that were greater than normal (n = 21, BNP level 11.0 +/- 1.5 pmol/l). We measured EAR of 76 of 90 patients with normal left ventricle systolic function, and 72 of the 76 patients had EAR < 1. CONCLUSION: These results indicate that renal dysfunction and systolic dysfunction as well as cardiac hypertrophy and lower than normal diastolic function contribute to the elevation of BNP levels in elderly inpatients who do not have overt heart failure.
Aged↗
A new structurally dissolvable self-reproducing loop evolving in a simple cellular automata space.
We constructed a simple evolutionary system, "evoloop," on a deterministic nine-state five-neighbor cellular automata (CA) space by improving the structurally dissolvable self-reproducing loop we had previously contrived [14] after Langton's self-reproducing loop [7]. The principal role of this improvement is to enhance the adaptability (a degree of the variety of situations in which structures in the CA space can operate regularly) of the self-reproductive mechanism of loops. The experiment with evoloop met with the intriguing result that, though no mechanism was explicitly provided to promote evolution, the loops varied through direct interaction of their phenotypes, smaller individuals were naturally selected thanks to their quicker self-reproductive ability, and the whole population gradually evolved toward the smallest ones. This result gives a unique example of evolution of self-replicators where genotypical variation is caused by precedent phenotypical variation. Such interrelation of genotype and phenotype would be one of the important factors driving the evolutionary process of primitive life forms that might have actually occurred in ancient times.
Artificial Intelligence↗
[Extreme decrease of serum total cholesterol and other lipid levels in elderly inpatients].
In this study 112 elderly inpatients (55 men, 57 women) were recruited. 1. Twelve elderly inpatients (5 men, 7 women) aged 82.5 +/- 7.4 years (M +/- SD) were investigated during 3 periods of dietary intake: good intake (period I), tube nutrition (period II) and fasting with intravenous fluid infusion (period III). Calorie, protein, carbohydrate, fat and cholesterol intakes were greater in period I than in periods II and III. Serum total and LDL cholesterols were lowest in period III, when serum HDL cholesterol, triglyceride and total protein were lower in period III than in period I. 2. One hundred elderly inpatients (50 men, 50 women) were divided into 4 groups according to type of decreased serum lipid and a control group. Serum total cholesterol only was decreased in group I, both serum total and HDL cholesterols were decreased in group II, both serum total cholesterol and triglyceride were decreased in group III, all 3 lipids were decreased in group IV and lipid levels did not change in the control group. There were 5 patients in group I, 28 patients in group II, 20 patients in group III, 27 patients in group IV and 20 patients in the control group. The patient's age ranged from 80.3 to 88.4 years and body mass index ranged from 14.7 to 18.4 kg/m2. Serum total protein decreased significantly in groups II-IV, to 5.6 to 5.7 g/dl. Serum total protein, and total cholesterol correlated positively (r = 0.525, p < 0.01), as did Calorie ingestion and serum total cholesterol levels (r = 0.554, p < 0.001). Therefore, severe hypocholesterolemia was accompanied by malnutrition and a decrease in Calorie or cholesterol intake. Serum total cholesterol levels during observation decreased most in group IV, followed by group II similar to serum HDL cholesterol levels. The amount of nutrient intake was smallest in group IV resulting in an extreme lowering of all 3 serum lipid levels.
Aged↗
[Factors that influence the serum of atrial natriuretic peptide and brain natriuretic peptide concentrations--is there a specific marker for senile patients?].
To evaluate factors that influence of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels in elderly people, we measured those levels in 54 men and 148 women (84.4 +/- 0.5 years old), and looked for associations of ANP and BNP with clinical factors and echocardiographic variables [left ventricular mass index and atrial to-early peak transmitral velocity ratio (A/E)]. ANP and BNP levels were 1.6 and 6.5 times higher than average. Sex was not a significant factor. We also looked for a link between cardiac rhythms and levels of ANP and BNP. Patients with atrial fibrillation had significantly higher levels of ANP and BNP than did patients with sinus rhythm. ANP and BNP levels were abnormally high in patients with left ventricular hypertrophy (LVH). We could measured A/E in 161 of 202 subjects; 154 of 157 subjects with normal LV systolic function had A/E > 1 which indicates abnormally low in LV diastolic function. Moreover, abnormally high LV diastolic stress might have been present, because 124 of 202 subjects had aortic regurgitation. We divided the patients into two groups: those 65 to 75 years old, and those over 75 years old. The older patients had significantly higher levels of ANP and BNP even without LVH and without a difference in renal function. Furthermore, the older patients had significantly higher levels of BNP even without LVH, with normal renal function, with sinus rhythm, with normal LV systolic function, and in NYHA Class I or II. These data indicate that ANP and BNP levels in people with senility may be associated with the cardiac rhythm and with abnormally low renal function, myocardial hypertrophy, abnormally high cardiac volume, and abnormally low diastolic function.
Aged↗
Does the plasma endothelin-1 concentration reflect atherosclerosis in the elderly?
BACKGROUND AND OBJECTIVE: Recently, attention has been focused on endothelin-1 (ET-1) as an indicator of atherosclerosis. However, normal levels of ET-1 are frequently found in elderly patients. We investigated the relationships between echocardiographic findings and ET-1 in 117 inpatients for rehabilitation. METHODS: The patients were 34 men and 83 women, 83.4 +/- 0.8 years old (mean +/- SE), with the following diseases: cerebrovascular diseases (n = 83), cardiovascular diseases of New York Heart Association Class I or II (n = 57), diabetes mellitus (n = 11) and hyperlipidemia (n = 12). Ejection fraction (EF) and left ventricular mass index (LVMI) were calculated by echocardiographic studies. RESULTS: The average ET-1 was within the normal range, but a significant positive correlation was observed between age and ET-1 (ET-1 = 1.8 +/- 0.1 pg/ml, r = 0. 248, p < 0.01). Moreover, plasma ET-1 was positively correlated to total cholesterol and to low density lipoprotein cholesterol in patients with a history of hypertension (n = 41, r = 0.318 and r = 0. 314, both p < 0.05). Gender was not a significant factor. There was no significant difference in ET-1 between patients with mild renal dysfunction (n = 54) and patients with normal renal function (n = 63) (blood urea nitrogen = 30.9 +/- 2.4 vs. 15.1 +/- 0.5 mg/dl, serum creatinine = 1.03 +/- 0.06 vs. 0.59 +/-0.02 mg/dl, ET-1 = 1.7 +/- 0.1 vs. 1.8 +/- 0.1 pg/ml), or between patients with (n = 50) and without (n = 67) left ventricular hypertrophy (LVMI = 146 +/- 6 vs. 83 +/- 2 g/m(2), ET-1 = 1.8 +/- 0.1 vs. 1.8 +/- 0.1 pg/ml). There was no difference in ET-1 between patients with EF <50% (n = 27) and EF >/=50% (n = 90) (ET-1 = 1.8 +/- 0.2 vs. 1.7 +/- 0.1 pg/ml). CONCLUSION: There were no significant relationships between echocardiographic findings and ET-1 in elderly subjects without overt heart failure. However, in patients with a history of hypertension, measuring ET-1 may be useful for estimating the extent of atherosclerosis.
Aged↗
Relationship between left ventricular geometry and brain natriuretic peptide levels in elderly subjects.
BACKGROUND: The plasma brain natriuretic peptide (BNP) level in elderly patients is elevated, but the mechanism of this increase is not clear. OBJECTIVE: To examine the relationship between left ventricular geometry and BNP levels in elderly subjects. METHODS: We investigated the effects of left ventricular (LV) geometry on plasma BNP levels by measuring these levels in elderly patients with or without LV hypertrophy. Patients were classified into 4 groups based on echocardiographic data: normal geometry; concentric remodeling; eccentric hypertrophy (EH), and concentric hypertrophy (CH). The samples were analyzed for BNP and endothelin-1 (ET-1). RESULTS: Among the 4 groups, there were no differences in plasma ET-1 levels, ejection fraction, percent fractional shortening, or indices of diastolic function. Plasma BNP levels in EH and CH were higher than those in the normal geometry and concentric remodeling groups. There was a good correlation between plasma BNP levels and the relative wall thickness in EH, and between plasma BNP levels and the posterior wall thickness in CH (r = -0.474, r = 0.396, respectively, both p < 0.05). There were also good correlations between plasma BNP levels and LV mass index (LVMI). A stepwise multiple regression analysis showed that age and LVMI were significant independent contributors to plasma BNP levels. CONCLUSIONS: These results suggest that aging, increased wall stress and the extent of cardiac hypertrophy contribute to elevated BNP levels in the elderly.
Aged↗