Infection with H. pylori is associated with an increased risk of gastric adenocarcinoma and may be a cofactor in the pathogenesis of this malignant condition.

Non-Hodgkin's lymphoma affecting the stomach, but not other sites, is associated with previous H. pylori infection. A causative role for the organism is plausible, but remains unproved.

In a cross-sectional study, serum dehydroepiandrosterone sulfate (DS) concentrations were measured in 981 men and 481 women, aged 11-89, yr. The resulting data were asymetrically distributed and were normalized by logarithmic transformation and analyzed by 5-yr age grouping (e.g. 15-19 yr, 20-24 yr, etc.). The DS concentration peaked at age 20-24 yr in men (logarithmic mean, 3470 ng/ml) and at age 15-19 yr in women (log mean, 2470 ng/ml). Mean values then declined steadily in both sexes (log mean at greater than 70 yr of age, 670 ng/ml in men and 450 ng/ml in women) and were significantly higher in men than women at ages from 20-69 yr. Analysis of 517 randomly selected sera (from women) which had been stored frozen for 10-15 yr gave results indistinguishable from values obtained from fresh specimens. In a supplementary study, a longitudinal analysis of weekly specimens from 4 normal men, aged 36-59 yr, revealed individual variability (mean coefficient of variation, 19%) and failed to demonstrate any monthly, seasonal, or annual rhythmicity. Based on the above analyses, a table of normal serum DS ranges for adult men and women is presented for use as a clinical reference.

No abstract

(DR) in the sense that MR increases rodent longevity, but without food restriction. We report here that MR also persistently increases total energy expenditure (EE) and limits fat deposition despite increasing weightspecific food consumption. In Fischer 344 (F344) rats consuming control or MR diets for 3, 9, and 20 mo, mean EE was 1.5-fold higher in MR vs. control rats, primarily due to higher EE during the night at all ages. The day-to-night transition produced a twofold higher heat increment of feeding (3.0°C vs. 1.5°C) in MR vs. controls and an exaggerated increase in respiratory quotient (RQ) to values greater than 1, indicative of the interconversion of glucose to lipid by de novo lipogenesis. The simultaneous inhibition of glucose utilization and shift to fat oxidation during the day was also more complete in MR (RQ ϳ0.75) vs. controls (RQ ϳ0.85). Dietary MR produced a rapid and persistent increase in uncoupling protein 1 expression in brown (BAT) and white adipose tissue (WAT) in conjunction with decreased leptin and increased adiponectin levels in serum, suggesting that remodeling of the metabolic and endocrine function of adipose tissue may have an important role in the overall increase in EE. We conclude that the hyperphagic response to dietary MR is matched to a coordinated increase in uncoupled respiration, suggesting the engagement of a nutrient-sensing mechanism, which compensates for limited methionine through integrated effects on energy homeostasis. energy expenditure; metabolic efficiency; oxidative metabolism; futile cycles; adipose tissue; dietary restriction DIETARY METHIONINE RESTRICTION (MR) extends lifespan by 30 -35% in rats (28, 31) and mice (27) by delaying all causes of death. The increase in lifespan is accompanied by a reduction in adiposity that occurs despite a paradoxical increase in weight-specific food consumption (25,28,46). Pair-feeding studies comparing rats fed the control diet to the amount of MR diet consumed by the MR group clearly show that dietary MR decreases metabolic efficiency (25, 46), but the underlying basis for the metabolic responses to dietary MR remains poorly understood. Short-(12 wk) and long-term (80 wk) consumption of the MR diet after weaning also reduced circulating triglyceride, insulin, and leptin while increasing plasma adiponectin (25, 29). Collectively, work to date makes a compelling case that limitation of fat deposition by dietary MR is associated with preservation of insulin sensitivity and significant improvements in metabolic markers of lipid metabolism. Using the tools of metabolic phenotyping to examine energy homeostasis and peripheral substrate utilization, we found that dietary MR produced a significant long-term increase in EE that was temporally linked to exaggerated thermogenic responses to feeding and modest increases in resting EE. These physiological responses to MR limited fat deposition and were associated with significant changes in the metabolic and endocrine function of brown and white adipose tissue. MR effectively increas...

SummaryReduced dietary methionine intake (0.17% methionine, MR) and calorie restriction (CR) prolong lifespan in male Fischer 344 rats. Although the mechanisms are unclear, both regimens feature lower body weight and reductions in adiposity. Reduced fat deposition in CR is linked to preservation of insulin responsiveness in older animals. These studies examine the relationship between insulin responsiveness and visceral fat in MR and test whether, despite lower food intake observed in MR animals, decreased visceral fat accretion and preservation of insulin sensitivity is not secondary to CR. Accordingly, rats pair fed (pf) control diet (0.86% methinone, CF) to match the food intake of MR for 80 weeks exhibit insulin, glucose, and leptin levels similar to control-fed animals and comparable amounts of visceral fat. Conversely, MR rats show significantly reduced visceral fat compared to CF and PF with concomitant decreases in basal insulin, glucose, and leptin, and increased adiponectin and triiodothyronine. Daily energy expenditure in MR animals significantly exceeds that of both PF and CF. In a separate cohort, insulin responses of older MR animals as measured by oral glucose challenge are similar to young animals. Longitudinal assessments of MR and CF through 112 weeks of age reveal that MR prevents age-associated increases in serum lipids. By 16 weeks, MR animals show a 40% reduction in insulin-like growth factor-1 (IGF-1) that is sustained throughout life; CF IGF-1 levels decline much later, beginning at 112 weeks. Collectively, the results indicate that MR reduces visceral fat and preserves insulin activity in aging rats independent of energy restriction.

This technique is useful in treating a variety of cutaneous depressions, including scars and wrinkles.

Little is known about the biochemical mechanisms responsible for the biological aging process. Our previous results and those of others suggest that one possible mechanism is based on the loss of glutathione (GSH), a multifunctional tripeptide present in high concentrations in nearly all living cells. The recent finding that life-long dietary restriction of the GSH precursor methionine (Met) resulted in increased longevity in rats led us to hypothesize that adaptive changes in Met and GSH metabolism had occurred, leading to enhanced GSH status. To test this, blood and tissue GSH levels were measured at different ages throughout the life span in F344 rats on control or Met-restricted diets. Met restriction resulted in a 42% increase in mean and 44% increase in maximum life span, and in 43% lower body weight compared to controls (P < 0.001). Increases in blood GSH levels of 81% and 164% were observed in mature and old Met-restricted animals, respectively (P < 0.001). Liver was apparently the source for this increase as hepatic GSH levels decreased to 40% of controls. Except for a 25% decrease in kidney, GSH was unchanged in other tissues. All changes in GSH occurred as early as 2 months after the start of the diet. Altogether, these results suggest that dramatic adaptations in sulfur amino acid metabolism occur as a result of chronic Met restriction, leading to increases in blood GSH levels and conservation of tissue GSH during aging.