Dietary restriction elongates life span by suppressing age-related diseases in experimental animals. It has received a great deal of attention in connection with the relationship between aging, nutrition, and oxidative stress because oxidative injury in several tissues is a prominent feature in the aging process. Although the oxidative stress theory of aging has currently gained popularity, the premise from which this hypothesis was derived is paradoxical because the same oxygen, that supports life in one hand threatens survival and promotes aging in the other. Until recently, no single experimental paradigm could offer satisfactory mechanistic explanations for this complex issue. Recent investigations using the life-extending dietary restriction regimen could offer satisfactory mechanistic explanations for this apparent self contradiction to life. The modulation of free radical-induced oxidative stress provided sufficient data to support the notion that dietary restriction's antiaging effect may come from its ability to tightly regulate the oxidative status of an organism. The result is the maintenance of cellular homeostasis, a hallmark of dietary restriction's action in the extension of life span. To date, we reported that dietary restriction (maintained on 60% of ad libitum feeding) suppresses age-related oxidative damage by modulating the amount as well as the fatty acid composition of tissue phospholipids. These remarkable findings have been incorporated into the new “membrane peorxidation cycle” concept. The intervention of this cycle appears to be an evolutionary process that the dietary restricted rats have adapted as a strategy to protect the membrane in an oxidative environment.
The actions of the thyroid hormone (T3) are modified by other hormones. Therefore, in the normal cell culture system, with serum as a medium ingredient, it is difficult to eliminate the influences of other hormones derived from the serum. In the present study, two experiments were conducted to clarify the effects of T3 on differentiation, growth and proteolysis (experiment 1), and concerted effects of T3 and insulin (experiment 2) in a serum-free culture with the use of muscle cells originated from chick embryo. Protein content and creatine kinase (CK) activity were examined as indices of growth and differentia-tion of the muscle cells, respectively, and Nz-methylhistidine (MeHis) release was examined as an index of myofibrillar proteolysis. It was observed that T3 suppressed both the muscle differentiation and proteolysis in the serum-free medium (experiment 1), though in our previous experiment they were enhanced by T3 in the serum-supplemented normal medium. On the other hand, T3 increased myofibrillar proteolysis and had no effect on muscle differentiation when insulin was included in the serum-free medium (experiment 2). These results clearly show that the effects of thyroid hormones on muscle differentiation and proteolysis are apparently different when serum is deprived from the medium, and these differential effects of thyroid hormone could be partially explained by an interaction with insulin, one of the growth factors in the serum.
The effects of ethanol (EtOH) administration at a high-dose level on the stimulatory action by bradykinin in vascular permeability were examined in rats, as compared with the effects of histamine and hyaluronidase. Oral administration (7.5g/kg) and intraperitoneal injection (5g/kg) of EtOH markedly potentiated the vascular permeability accelerated by bradykinin, but they suppressed in reverse such effects induced by histamine and hyaluronidase. EtOH did not affect the stimulatory action of bradykinin on the vascular permeability when intracutaneous injection was done under the coexistence with bradykinin. The blood pressure was found to descend 3 0 min later, though there was a transient rise immediately after the oral administration of EtOH (7.5g/kg). The oral administration of EtOH (7.5g/kg) caused no change in both enzyme activities of aspartic acid aminotransferase and alanine aminotransferase in blood for 3h. The intraperitoneal injection of EtOH (5g/kg) lowered the blood bradykinin level and increased the blood hyaluronidase activity. In vitro, EtOH elicited a concentration-dependent increase in the kallikrein activity, trypsin activity, and bradykinin-decomposed activity in plasma. These results strongly suggest that vascular permeability results from elevation in the bradykinin level, direct action of EtOH on inflamed skin site, and actions of EtOH or its metabolites on bradykinin-regulator, which involves bradykinin receptor and NO and endothelin productions.
The objective of the present study was to establish that HDL3 has a greater antiperoxidative effect on the peroxidative modification of LDL than HDL2 has. The protective influence of HDL subfractions on this form of LDL modification was examined in samples by measuring the concentration of thiobarbituric acid-reactive substance (TBARS), as well as the electrophoresic mobility of LDL. LDL was incubated for 96 hours in phosphate-buffered saline (PBS) alone, without the addition of transition-metal ions or in the presence of PPS and HDL2 or HDL3. All samples were subjected to agarose gel electrophoresis. Both HDL2 and HDL3 significantly inhibited peroxidative modification of LDL, as assessed by electrophoretic mobility, but this effect was much more pronounced with HDL3. HDL3 may play a more important role than HDL2 in the prevention of atherosclerosis in vivo by more effectively inhibiting LDL peroxidation.
The objective of this study was to verify the effect of soaking on the factors causing flatulence in the common bean (Phaseolus vulgaris, L.) cv. IAC-Carioca during domestic preparation. A biological assay using recently weaned (21 days) male Wistar rats provided the Food Conversion Efficiency (FCE) and the Net Protein Ratio (NPR). Five treatments were carried out with isocaloric (350.9±37.9 kcal/100g) and isoprotein (12.0±0.5%) experimental diets, with the following protein sources, beans cooked without soaking (BNS), beans soaked and cooked with the soaking water (BSWW), beans soaked and cooked without the residual soaking water (BSNW), control diet (casein) (CC), casein plus the total soluble solids found in the soaking water (CSS) for comparative purposes, and an aproteic diet (AP) for corrective purposes, all diets offered ad libitum. The contents of raffinose-type oligosaccharides were determined in the different domestic preparations of the beans. Significant reductions were observed in the contents of the oligosaccharides raffinose (25.0%), stachyose (24.8%), and verbascose (41.7%), and in the contents of total sugars (80.6%), reducing sugars (58.2%), nonreducing sugars (90.3%), and starch (26.8%) when soaking took place before cooking and elimination of the soaking water not absorbed by the beans (BSNW) was used. No significant difference (p>0.05) was observed between the values for FCE and NPR of the control diet (casein) and control diet plus soaking water soluble solids. Neither was any significant difference between the values for the different bean treatments found, though the values for FCE and NPR were lower than those obtained for casein treatments. Thus it was verified that although the domestic preparation of the common bean significantly reduced the contents of raffinose-type oligosaccharides, total reducing and nonreducing sugars and starch, it did not interfere with its nutritive value.
Elevated plasma total homocysteine (tHcy) levels have been established as a risk factor for occlusive cardiovascular disease. Also known is that plasma folate and vitamin B12 influence homocysteine metabolism as cosubstrate and cofactor, respectively. However, not much information is available describing plasma tHcy levels and their relationship to plasma folate and vitamin B12 status in Koreans. We measured the plasma levels of tHcy, folate, and vitamin B12 in 195 adults (99males, 96 females; 23-72y old in the lower middle class). The mean plasma tHcy levels of males, 11.18±3.88, imol/L, was significantly higher (p<0.001) than that of females, 9.20±2.65, imol/L. The distribution of tHcy levels of males showed a wide range, 3-50, imol/L, with a long tail toward higher values. Thus the incidence of hyperhomocysteinemia (≥15μmol/L) in males, 10.1%, was significantly higher (<0.02) than the 2.1% in females. As age increased, plasma tHcy levels tended to be higher in females, Therefore, sex differences in plasma tHcy levels disappeared in subjects over fifty. On the other hand, both plasma folate (6.47±3.06 vs 7.96±3.55 ng/mL, p<0.01) and vitamin B12 levels (537.0±222.0 vs. 664.1±309.8 ng/mL, p<0.01) were significantly lower in males than in females. A plasma folate deficiency (<3.0ng/mL) was found in 6.1% of males and 2.1% of females. And a vitamin B12 deficiency (<150pg/mL) was detected in 2.0% and 1.0%, respectively. Plasma tHcy levels were related with inversely plasma concentrations of folate (r=-0.37249, p<0.001) as well as vitamin B12 (r=-0.22560, p<0.01) in both sexes. Plasma levels of tHcy and the prevalence of hyperhomocysteinemia in Korean adults are similar to findings in the West. Our results indicate that male adults may be in worse condition for cardiovascular disease (CVD) than females. And improving folate and vitamin B12 status may reduce plasma tHcy level, which may be more important in males.
The effects of brewer's yeast, casein, and soy protein intakes on the absorption and retention as well as the incorporation into hemoglobin and systemic iron stores of dietary iron were examined in an animal experiment with growing rats. Relative biological values (RBV) of iron in the rats fed casein (C), soy protein (SP), and yeast (Y) diets were 1.00, 0.31 and 1.77 respectively. The apparent absorption of iron in Y-diet-fed rats was significantly higher than that in C- or SP-diet-fed rats. The hemoglobin regeneration efficiency (HRE) of iron in Y group was significantly higher than those in C and SP groups. As a result of search for iron-absorptive enhancers (IAE) in yeast, RBV and HRE of the yeast-cell-wall-including diet turned out to be significantly higher than those of its lacking diet. These results suggest that IAE occurring in the yeast cell wall may be effective for iron absorption.
Anthocyanins are used for food color, and they are widely distributed in the human diets, suggesting that we ingest considerable amounts of anthocyanins from plant-based daily diets. We have demonstrated that a typical anthocyanin, cyanidin 3-O-β-D-glucoside (C3G), suppressed the zymosan-induced inflammatory response in rats when it was orally administered. The elevation of the peritoneal exudate NOX, tumor necrosis factor (TNF) α interleukin-1β (IL-1β), IL-6, and the cytokine-induced neutrophil chemoattrac-tant-1(CINC-1) concentrations were significantly suppressed by the administration of C3G. The zymosan treatment resulted in an increase in the serum a2-macroglobulin and decreases in the serum albumin and transferrin levels, which are recognized as acute phase proteins. However, these levels were normalized by the administration of C3G. The inducible nitric oxide synthase (iNOS) protein level in the peritoneal exudate cells was markedly elevated in the control group treated with zymosan. However, the administration of C3G significantly reduced the level of iNOS in the peritoneal exudate cells. Taken altogether, our findings provide a biochemical basis for the use of C3G as a functional food factor and can also have important implications for the prevention of the NO-mediated inflammatory diseases.
Mucin secreted into the alimentary tract often forms a mucus layer on the mucosa and is believed to protect the underlying epithelium against various factors in the lumen. We developed an improved histological technique for the evaluation of the mucus layer in the rat cecum. We used this technique to compare the effect of three nonstarch poly-and oligosaccharides on the status of mucus layer. Rats were divided into four groups (fiber-free [FF], cellulose [CEL], fructooligosaccharide [FOS], or guar gum [GG]). The frozen cecum with its contents was cut into cross-sections (5mm thick) and fixed overnight in half-strength Bouin's solution. The sections were then transferred to 80% ethanol for 24 h. After being stained with alcian green, the mucus layers were clearly visualized in thin sections of the rat cecum, except for those that received FOS where the mucus layer had disappeared; the strong signal of mucus was seen in the cecal digesta of FOS-fed rats. Our histological method successfully provided information about the status of mucus layer that is important for an assessment of the epithelial state in the intestine.
Microencapsulated ferrous sulfate (SFE-171) and ferric orthophosphate in Petit-Suisse cheese were examined for iron bioavailability by the prophylactic method. The iron sources were industrially added to different samples of Petit-Suisse cheese, which were mixed with other food components in our laboratory before use. A reference standard diet inclusive of nonmicroencapsulated ferrous sulfate and a control diet low in iron content were prepared in the laboratory. The final iron content in the fortified diets was approximately 15 mg Fe/kg diet. These diets were administered to weaning rats for 23 days. The iron bioavailability was evaluated as the ratio of iron incorporated into hemoglobin to oral iron intake, thereby being estimated as 62.6±8.8% for ferrous sulfate and 59, 2±10.6% for SFE-171, which were significantly effective at p<0.01 compared to 43, 4±10.5% for ferric orthophosphate. It thus turned out that SFE-171 was stable through industrial processing with Petit-Suisse cheese as the food vehicle and served as an iron fortifier equal to ferrous sulfate in bioavailability.
Red wine and its constituents have been shown to stimulate endothelium-de-pendent and nitric oxide (NO)-mediated vasorelaxation in vitro in the isolated and precon-tracted aortic rings. The present study investigated if this occurred in vivo in rabbits, which chronically consumed a moderate amount of red wine. Nωnitro-L-arginine-methyl ester (L-NAME) and L-arginine was infused into the rabbits that consumed red wine (7mL/kg/d), ethanol (99.5%, 0.8mL/kg/d), or water alone for 4 weeks, and the vaso-constrictive/-dila-tive response was studied in the renal artery. Following treatment with L-NAME (30mg/kg), the renal blood flow rate decreased and renal vascular resistance increased. Only in the ani-mals consuming red wine did a subsequent administration of L-arginine (300mg/kg) in-crease the renal blood flow rate and decrease the renal vascular resistance. The effects were associated with the increase in the renal NO metabolite (nitrite/nitrate, NO2-/NO3-) pro-duction rate. From the present in vivo model, it is suggested that vasorelaxation by L-argi-nine is through the NO pathway and that the effects observed in the animals consuming the red wine cannot be attributed to alcohol alone.