The relationship between measures of obesity and incident heart failure: The multi‐ethnic study of atherosclerosis

Objective : To evaluate the strength of association of body mass index (BMI) and waist circumference (WC) with incident heart failure (HF), exploring our associations by ethnicity and age. Design and Methods : 6,809 participants, aged 45‐84 years old, without clinical cardiovascular disease (2000–2002), from the Multi‐Ethnic Study of Atherosclerosis were included. Cox‐Proportional hazards models were used to examine associations of BMI and WC with incident HF. The predictive abilities of BMI and WC were compared using receiver operating characteristic curves. Results : Over a median follow‐up of 7.6 years, there were 176 cases. BMI and WC were associated with incident HF in men (1.33 [1.10‐1.61] and 1.38 [1.18‐1.62], respectively] and women (1.70 [1.33‐2.17] and 1.64 [1.29‐2.08], respectively). These associations became non‐significant after adjusting for obesity‐related conditions (hypertension, dysglycemia, hypercholesterolemia, left ventricular hypertrophy, kidney disease, and inflammation). The associations of BMI and WC did not vary significantly by ethnicity or age‐group, but were inverse in Hispanic men. The area under the curve for BMI and WC was 0.749 and 0.750, respectively, in men and 0.782 and 0.777, respectively, in women. Conclusions : The association between obesity and incident HF is largely mediated by obesity‐related conditions. BMI and WC have similar predictive abilities for incident HF.     

Effects of different light wavelengths at equal irradiance on testis weight, protein content, and K-paranitrophenylphosphatase activity in the Syrian hamster

The effects of different light wavelengths at equal irradiance on testis weight, testis protein content, and testis K-paranitrophenylphosphatase (K-pNPPase) activity were studied in the Syrian hamster. One group (long photoperiod) was maintained on a light:dark cycle of 14:10, and another group (short photoperiod) on a cycle of 10:14. Five other groups were maintained on a cycle of 10:14 but with a one hour pulse of equally intense illumination in the middle of the dark period with UV, blue, green, yellow or red light. Animals exposed to a long photoperiod or UV, blue or green light pulses had significantly greater testis weights--up to eightfold greater than those in the yellow or red or short photoperiod groups. Organ protein content closely paralleled organ weight, but the protein/wet weight ratio was consistently higher in the large organ groups. K-pNPPase and Mg-pNPPase activities were significantly higher in the large organ groups, even when expressed per mg protein. Therefore, at a balanced irradiance of 0.2uW/cm2, light wavelength exerts a profound effect on testicular weight, protein content, and K-pNPPase and Mg-pNPPase activities. Testicular involution is a process that is selective with regard to protein biosynthesis.     

Low level lead inhibits the human brain cation pump.

The impact of low level lead exposure on human central nervous system function is a major public health concern. This study addresses the inhibition of the cation pump enzyme Na, K-ATPase by low level lead. Human brain tissue was obtained at autopsy and frozen until use. Brain homogenates were preincubated with PbCl2 for 20 min at 0 degrees C. Inhibition of K-paranitrophenylphosphatase (pNPPase), a measure of the dephosphorylation step of Na,K-ATPase, reached steady state within 10 min. K-pNPPase activity, expressed (mean +/- SEM) as a percentage of control (45.2 +/- 2.7 nmol/mg/min), fell to 96.3 +/- 0.9% at 0.25 uM [PbCl2] to 82.0 +/- 1.6% at 2.5 uM [PbCl2] in homogenates prepared from normal brain. Similar results were obtained with homogenates prepared from brains of patients with a history of alcohol abuse and of those with other miscellaneous conditions. Since the mean blood level of lead in the United States has ranged recently from 9.2 to 16.0 ug/dl (0.44 to 0.77 uM), these results indicate that current in vivo levels of lead exposure may impair important human brain function.     

Different effects of aging on the opioid mechanisms controlling gonadotropin and cortisol secretion in man

The present study was undertaken in order to assess the influence of aging on the endogenous opioid control of gonadotropin and adrenocorticotropin/cortisol secretion in man. For this purpose, the capability of the opioid antagonist naloxone to increase circulating levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and cortisol was tested in male subjects of different ages. Thirty normal men were randomly chosen and divided into 3 groups by age: group I = 22-40 years (n = 10); group II = 41-59 years (n = 10); group III = 62-80 years (n = 10). Since the men of group III showed higher basal serum gonadotropin concentrations than the subjects of group I and group II, we selected from a large population a fourth group of elderly men with normal basal LH and FSH levels: group IV = 61-82 years (n = 7). All subjects were tested for 120 min during the intravenous administration of naloxone (4 mg given in an intravenous bolus at time 0, plus 10 mg infused for 2 h). Control tests with normal saline instead of naloxone were performed in all groups. All subjects had similar blood testosterone and cortisol levels, whereas LH and FSH concentrations were significantly higher in group III than in groups I, II and IV. Naloxone increased plasma cortisol concentrations by 50% in all groups. The cortisol secretory response followed a similar pattern regardless of age.(ABSTRACT TRUNCATED AT 250 WORDS)     

Nutrient content and seasonal fluctuations in the leaf component of coark-oak (Quercus suber L.) litterfall

Nutrient content and seasonality of the leaf component in cork-oak litterfal were studied over a two year period in two cork-oak forest sites differing in biomass and edaphic condition in the north-eastern Iberian peninsula. Fallen senescent leaves compared to young leaves showed higher non-mobile nutrient concentrations and lower mobile nutrient concentrations, specially P, N, K, and Mg. At both sites, seasonal fluctuations affected both leaf production and leaf mineral content. The maximum leaf fall period correspond to the start of the vegetative growth and to the lowest N and P concentration in the falling leaves. The opposite was true for the winter, when litterfal was minimal and N and P content in falling leaves was at a maximum.The comparison between falling leaves and canopy leaves suggests that the analysis of fallen leaves can be a useful measure of N and P nutrition in cork-oak. We found site dependent differences in nutrient content and nutrient remobilization. In comparison with Q. ilex, although litter production was in the same range, nutrient retranslocation was greater for Q. suber.