A first and efficient direct optical resolution of biotin dia-stereomers, (±)-biotin and (±)-epibiotin, was accomplished by a reversed phase high-performance liquid chromatography on cellulose tris (3, 5-di-methylphenylcarbamate) coated on silica-gel.
Folic acid was irradiated under cooling at 10°C in a slightly alkaline solution with a ceramics radiator (surface temperature: 68°C). The difference spectra of the folate against the non-irradiated one showed a red shift. The difference absorbance of the peak at the wavelength above 320 nm increased with the radiation time. Affinity of the irradiated folate (FA(+)), which is a competitive inhibitor, to the irradiated xanthine oxidase (XO(+)) more increased than the irradiated substrate with increasing temperature of the reaction, while the affinity to the non-irradiated enzyme (XO (-)) significantly decreased. The difference of the standard entropy change in the FA(+)/XO (-) system to that in the non-irradiated FA(-)/XO(-) system, i.e., Δ(ΔSS) gave a large negative value, while Δ(ΔSS) of the FA(-)/XO(+) system gave a large positive value. An increase in the Δ(ΔSS) of the FA(+)/XO(+) system over-came an increase in the enthalpy difference Δ(ΔHS) of the system, and then the free-energy difference Δ(ΔGS) resulted in the most negative value. This means that the driving force by the reaction system depends on an entropy effect. These results indicate that the red shift of the spectra of FA(+) is due to a solvent ordering effect obtained by the radiation, and that the affinity of the FA(+) to the active center of XO(+) increases when XO has also received the ordering effect.
Changes in platelet aggregability patterns and lipid perox-ide levels and their relationship were examined in DC CA-salt hyperten-sive rats during the development of hypertension. In addition, the effect of vitamin E treatment on those changes was also investigated. The blood pressure of the hypertensive rats was 188, 201, 212mmHg on day 11, 17, and 23, respectively. In the hypertensive rats, both aggregability and granule content in platelet decreased on day 12, 18, 24, and marked decreases were observed on day 24. These data suggested the appearance of exhausted platelets, which had been already activated in vivo due to the hypertension. Marked increases in lipid peroxide levels in serum, the heart and the kidney were observed on day 24 in the hypertensive rats. Increase in serum urea nitrogen was also observed in the hypertensive rats on day 24, suggesting the dysfunction of the kidney. Vitamin E treatment did not prevent in vivo platelet activation due to hypertension, but greatly prevented the elevations of lipid peroxides in serum, the heart and the kidney, and serum urea nitrogen. These results suggested that in vivo platelet activation, an increase of lipid peroxides, and renal dysfunction occur in this order due to hypertension, and that the latter two are significantly prevented by vitamin E treatment.
The effect of vitamin E (dl-a-tocopheryl acetate) on T cell differentiation in thymus of F344 rats was examined in this study. The rats were divided into three groups: vitamin E-free, regular and high vitamin E groups and fed a diet containing various levels of vitamin E (0, 50, and 585 mg/kg diet) for 7 weeks. The number of thymocytes was significantly lower in the vitamin E-free group relative to the regular group. Although the proportions of both CD4 CD8- and CD4-CD8+ T cells in thymocytes were significantly greater in the high vitamin E group, the proportion of CD4+CD8- T cells inversely decreased in vitamin E-free group compared to that of the regular group. The ratio of CD4+ CD8-/CD4-CD8 T cells increased in the high vitamin E group (p<0.01) and significantly decreased in the vitamin E-free group (p<0.001) compared to that of the regular group. Although the marked changes of T cell subsets were not seen in peripheral blood lymphocytes (PBL), the ratio of CD4+CD8-/CD4-CD8 T cells was significantly lower in the vitamin E-free group and significantly greater in the high vitamin E group compared to that of the regular group. Production of interleukin (IL) 2 by thymocytes following the stimulation with Con A for 48 h increased about threefold in the high vitamin E group compared to the regular group. Conversely, thymocytes from rats fed the vitamin E-free diet showed a significant decrease of IL2 production compared to that of the regular group. Prostaglandin E2 (PGE2) production from thymocytes was significantly lower in the high vitamin E group compared to that of the regular group, whereas thymocytes of rats fed the vitamin E-free diet showed a significant increase of PGE2 production compared to that of rats fed the regular diet. Furthermore, in vitro addition of indomethacin provided a restoration of IL2 production from thymocytes of rats fed the vitamin E-free diet to the level of rats fed the regular diet. These results suggest that vitamin E plays an important role in T cell differentiation in thymus, which may be related to the action of vitamin E as antioxidant.
We performed a pharmacokinetic analysis of the blood thiamin profile after oral administration of thiamin tetrahydrofurfuryl disulfide (TTFD) to healthy adults. To distinguish between thiamin derived from TTFD ingestion and that from previous dietary intake, the baseline thiamin level was subtracted from the apparent blood vitamin levels measured after administration. Following administration of 100 mg of TTFD, the peak blood thiamin level was almost 10 times the baseline level and the blood thiamin profile could be simulated by a two-compartment model to obtain reasonable pharmacokinetic parameters. When the blood thiamin profile for a 10-mg dose of TTFD was estimated using scaled-down pharmacokinetic parameters derived at the 100-mg dose level, a reasonable fit for the raw data obtained at 10-mg dose was obtained. Therefore, the parameters derived from the data at a dose of 100 mg appeared to be reliable. Since even 180 mg of TTFD is completely absorbed and the absorption ratio is independent of the dose, it can be concluded that gastrointestinal absorption of TTFD is good within the dose range.
The effects of whey mineral complexes (WMC1 and WMC2) on bone metabolism were studied in male growing rats. The contents of Ca, P, and protein in WMC 1 were 18.2, 8.4, 2.3%, respective-ly, whereas those of WMC2 were 26.4, 14.6, and 10.5%, respectively. WMCs were added to diets as a sole source of Ca: the levels of dietary Ca were 0.3 and 0.6%. CaCO3 was used as a reference. There was no difference in body weight gain and quantitative values for Ca balance among the groups at the same level of dietary Ca. Rats fed WMC2 had a higher femoral Ca and bone density of humerus. The bone properties in rats fed WMC 1 were not as high as those in rats fed WMC2. The P absorption and absorption rate were affected significantly by the type of dietary Ca source as well as the levels of dietary Ca. The percent of tubular reabsorption of P of rats fed WMC1 or WMC2 had a tendency to be higher than that of rats fed CaCO3 at each dietary Ca level. The results of urinary cAMP excretion showed that the parathyroid hormone func-tion in rats fed WMC2 was relatively lower. The differences in minerals and other constituents between WMC1 and WMC2 are discussed from the viewpoint of bone metabolism.
The influence of the gastrointestinal microflora on the digestibility and biological value of casein was investigated in germ-free (GF) and conventionalized (Cvd) Fischer 344/Yit rats fed an 8% casein diet. There was no significant difference in the true digestibility of casein between GF and Cvd rats, but the apparent digestibility was higher in Cvd than in GF rats. The biological value of casein was significantly higher in GF than in Cvd rats. In the casein diet period, body weight gain was almost the same in GF and Cvd rats, but food intake was significantly greater in Cvd than in GF rats. The excretion of fecal N was similar in GF and in Cvd rats whereas more urinary N was excreted in Cvd than in GF rats. In the protein-free diet period, metabolic fecal N per 100g of food intake was significantly higher in GF than in Cvd rats, but there was no difference in the excretion of endogenous urinary N per 100 grams of body weight between the GF and Cvd rats. The results indicate that the presence of a gastrointestinal microflora does not influence the true digestibility, but increases the apparent digestibility and decreases the biological value of casein at an 8% level in the diet.
The present study was conducted with growing rats to examine effects of addition of 0.3, 1.0, 2.5, and 500 L-cystine to 10 or 2500 casein diet on tissue ascorbic acid and on serum cholesterol, a-tocopherol, and ceruloplasmin activity. Addition of 0.3-1% cystine to 10% casein diet caused the maximum growth and addition of 5% cystine to 25% casein diet depressed the growth. Increases in liver levels of ascorbic acid and in serum levels of cholesterol and a-tocopherol were observed with addition of 5% cystine to 10 and 25% casein diets as compared to the diets without addition of cystine. Addition of 0.3-5% cystine to 10% casein diet and addition of 500 cystine to 25% casein diet caused a decreased activity of serum ceruloplasmin. The changes in liver ascorbic acid, serum cholesterol, and serum a-tocopherol and in ceruloplasmin activity by dietary cystine correlated with the changes in liver levels of non-protein sulfhydryl.
The metabolic fate of L-[35S]cysteine was investigated in growing rats fed on diets containing graded levels of protein calorie percentages (0, 5, 10, 15, and 30 PC%) by use of purified whole egg protein at 4, 100 kcal of metabolizable energy per kilogram of diet. Incor-poration of radioactivity into body protein during the 12 h period after intraperitoneal injection of 35S-cysteine was about 70% of the dose in the 0 to 15 PC% group, but it decreased significantly in the 30 PC% group, showing a break point at around 15PC% in the diet. A considerable amount of the radioactivity was recovered in the carcass soluble fraction in which the label in the taurine fraction gradually in creased with increasing dietary protein levels from 0 to 30 PC%. Urinary excretion of total 35S during the 12 h period was depressed in the lower PC% groups, but it increased in the 30 PC% group, about 23% of the dose being recovered. More than 50% of the urinary radioactivity was present in the inorganic sulfate fraction, but less than 10% was in the taurine fraction. These results indicate that cysteine sulfur is preferentially utilized for body protein synthesis, especially in dietary protein depletion, and that the oxidation of cysteine sulfur to taurine and inorganic sulfate is elevated with higher PC% in the diet. The response pattern of cysteine sulfur metabolism to dietary protein intake resembled that of cysteine carbon metabolism which was previously reported.
The α-tocopherol content of breast milk was measured in 71 mothers of preterm and term infants in China. The mean α-tocopherol content of breast milk was much lower than that reported in developed countries. α-Tocopherol levels were higher in colostrum and then de-creased in the transition milk. Mothers of preterm infants produced colostrum with a slightly higher α-tocopherol content than that of the mothers of term infants. However, α-tocopherol levels in transition milk were similar in both groups.
The microsomal synthesis of docosahexaenoic acid (DHA) from radiolabeled eicosapentaenoic acid was tested in vitro using the livers of crab-eating monkeys. The test animals included 1 fetus (embryonic day 120), 2 neonates (full-term, embryonic day 165), and 2 adults. DHA was formed equally in the liver microsomas of each animal. Neonatal livers were found to contain higher percent of arachidonic acid than adult livers in both phosphatidylcholine and phosphatidylethanolamine. DHA contents remained constant in the liver phospholipids of all test animals.
The effects of proteins, peptides, and amino acid mixtures on the recovery from 70% hepatectomy were compared in rats. In Experiment 1, the most suitable time for the comparison was studied. Rats weighing 250 g after 70% hepatectomy were fed 20% casein diet. On day 0, 1, 2, 3, 4, 6, 8, 11, 15 post-operation, 3-5 rats were killed for the observation of recovery. The recovery time, evaluated by daily food intake, body weight gain, liver weight and compositions, and hematologic values was about 10 days. For the comparison of different nitrogen sources, we estimated that the 6th day after the operation when the animals did not fully recover was suitable. In Experiment 2, rats of each group after hepatectomy were fed one of 14 experimental diets containing protein (3 types), peptides (8 types), or amino acid mixture (3 types) for 5 days and killed on the 6th day after the operation. Daily food intake, body weight gain, liver weight and compositions, and hematologic values were measured and pathological examination was also done. The effect of different nitrogen sources were similar on the recovery after 70% hepa-tectomy with only a few minor exceptions in rats.
An anti-obesity effect was observed for cholest-4-en-3-one (cholestenone) which is an intestinal catabolite of cholesterol. Body weight gain and body fat accumulation of CDF 1 mice were inhibited by 0.5% dietary exposure to this chemical. Dose response for the effect of cholestenone was found to increase as the dose rose from 0.1 to 0.3% and 0.500. No obvious anomaly due to consumption of cholestenone was detected by necropsy and clinical observation. The mechanism of this effect of cholestenone is not known at present, but it was not due to anorexia.