We measured serum superoxide dismutase activity by electron spin resonance, using 100mM 5, 5-dimethyl-1-pyrroline-N-oxide (DMPO) as a trap. The addition of superoxide dismutase decreased the height of the DMPO-OOH signal produced by the hypoxanthine-xanthine oxidase system. Serum superoxide dismutase activity was determined from a quantitative line for superoxide dismutase. When bovine Cu, Zn-superoxide dismutase (50, 000U/kg) was injected intravenously into rats, the superoxide dismutase activity decreased almost linearly with a half life of about 6min. This method allowed direct detection of superoxide radicals and new measurement of superoxide dismutase activity.
It is generally accepted that ingestion of sucrose in large quantities elevates blood pressure (BP). Less certain is whether starch and other refined carbohydrates (CHO) have similar effects. Using spontaneously hypertensive rats (SHR) and normotensive control rats (WKY), we show that glucose, fructose, and starch fed to rats either in solution or in dry form elevate BP to a similar degree as sucrose. The changes in BP brought on by various refined CHO were greater in SHR than in WKY. The elevations did not consistently correlate with differences in body weight, amount of dry matter or fluid intake, the quantities of sodium and potassium ingested, or to changes in the various blood chemistries examined. We conclude that other refined CHO (glucose, fructose, and starch) like sucrose raise BP significantly. This effect on BP is rapid (within days) and reversible, at least to some extent.
Age-related changes in serum and liver lipid peroxide levels in the male senescence-accelerated mouse (SAM) were studied over a period from 1 to 10 months after birth. The degree of senescence of SAM-P/1 mice (accelerated senescence-prone mice) began to be higher at 4-6 months after birth compared with that of SAM-R/1 mice (accelerated senescence-resistant mice). Serum lipid peroxide levels of SAM-R/1 mice increased gradually with age. On the contrary, serum lipid peroxide levels of SAM-P/1 mice increased markedly at 2-3 months after birth, and the levels were significantly higher than those of SAM-R/1 mice at that time. Thereafter, the serum lipid peroxide levels of SAM-P/1 mice tended to be higher than those of SAM-R/1 mice until 8 months after birth. The pattern of changes in liver lipid peroxide levels of SAM-P/1 mice was similar to that in their serum lipid peroxide levels. A significant increase in liver lipid peroxide levels of SAM-P/1 mice was observed at 2 months after birth as compared with those of SAM-R/1 mice. Such increase in lipid peroxide levels in SAM-P/1 mice was found to occur prior to the appearance of age-related clinical signs, suggesting that lipid peroxides increased in the early period of the life may cause the initiation or promotion of the aging process.
This study was designed to evaluate the metabolic and hormonal effects of various combinations of carbohydrate loads containing glucose, fructose, and xylitol in a rabbit model utilizing laparotomy of depressed glucose metabolism. The animals were divided into eight groups according to carbohydrate ratios of the total parenteral nutrition (TPN) solution. TPN with a nonprotein calorie ratio of 150 was administered for three days at an isocaloric dose of 112kcal/kg/day. The plasma glucose level and urinary excretion rates were the lowest in the group receiving a 8:4:2 combination of glucose, fructose, and xylitol (GFX842). The daily nitrogen balance for this group was significantly higher than that of groups with other carbohydrate combinations. Solutions of 14C-labeled glucose, fructose, and xylitol in various ratios were also administered to evaluate the usefulness of the GFX842 mixture from the aspect of efficient energy utilization. Of the various combinations GFX842 was found to be the most effective in utilization of carbohydrates, as judged from the expired 14CO2 excretion rate, plasma level of [14C]glucose, [14C]fructose, and [14C]xylitol, and the endogenous glucose level. These data imply that the ratio of the carbohydrates in the GFX842 mixture is the most important factor with regard to the control of plasma glucose and the utilization of carbohydrates in the state of impaired glucose tolerance.
D-Glucosone (D-arabino-hexos-2-ulose) was prepared by use of an immobilized glucose 2-oxidase-catalase gel, and the biochemical response to D-glucosone by three kinds of glucose-recognizing systems in higher animals was studied. The enhanced motility of rat stomach caused by glucopenia was reduced by carotid arterial injection of D-glucosone like in the case of D-glucose. D-Glucosone (16.7mM) showed no effect on the secretion of insulin from the pancreatic islets of the rat, and the secretion of insulin caused by D-glucose (16.7mM) was markedly depressed by the addition of D-glucosone (16.7mM). The relative sweetness of D-glucosone, compared with that of 5% sucrose as 1.0, was estimated to be 0.4-0.6, which is similar to that of D-glucose. These results suggest that D-glucosone is a useful model compound for D-glucose to investigate the biochemical mechanism of glucose-recognizing systems.
Some properties of epidermal growth factor (EGF)-like immunoreactive substances (EGF-LI) found in human platelets were studied. Human platelets were treated with acidic, alkaline, or hypotonic solutions or by freezing-thawing. Then after centrifugation the hEGF-LI in the resulting supernatant was examined by our rapid enzyme immunoassay system for the presence of hEGF-LI's released from the platelets. The amount of hEGF-LI released from platelets varied with the treatment, the alkaline or freezing-thawing treatment being the most effective in liberating the hEGF-LI. The hEGF-LI was applied to a column of Sephadex G-100 and was detected in four fractions showing molecular weights of about 280, 56, 20, and 6kdaltons. The high molecular weight hEGF-LI's having molecular weights of 280 and 56kD were converted to 20kD one by treatment with 2-mercaptoethanol. So it appears that some of the hEGF-LI's in platelets may exist in a complex form through disulfide linkages with some proteins in the platelets.
We examined whether or not endogenous plasma lipoprotein lipase (LPL) and hepatic lipase (HL) activities are stimulated by oral administration of dextran sulfate (DS). The diurnal fluctuations of the plasma activities of the lipases were studied together with the diurnal profiles of triglyceride in chylomicrons and in very low density lipoprotein (Chyl-VLDL-TG), and apoproteins (C-II, C-III, and E) in 8 young healthy men during the administration of a test diet and during the administration of the test diet combined with a total daily dosage of 1, 800mg of DS. Chyl-VLDL-TG decreased before supper and the decrease was more marked in the DS group than in the control group. The diurnal plasma apoproteins C-II, C-III, and E showed a gradual but significant reduction when DS was not given, but the levels did not decrease when DS was administered. In the control group, the LPL activity showed only a minute fluctuation which was characterized by an insignificant increase after each meal. In the DS group, on the other hand, the LPL activity showed a stepwise increase, and the activity before supper (27.5±6.6nmol FFA/ml/h, M±SE) was significantly greater (p<0.05) than the activity in the fasting plasma (8.3±1.4nmol FFA/ml/h). In contrast, the HL activity did not show any significant fluctuation in either group. Only the HL activity at 12 noon in the DS group (17.4±5.5nmol FFA/ml/h) tended to be greater than the activity at 8a.m. (8.8±1.8nmol FFA/ml/h). Thus, the oral administration of DS was shown to promote the diurnal Chyl-VLDL-TG clearing in healthy men by stimulating the release of LPL into circulation and by maintaining the LPL co-factors such as apoproteins C-II, C-III, and E.
Utilization of fructooligosaccharides, 1F-(β-fructofuranosyl)n-1-sucrose, which are not digestible in the small intestine but are fermentable by intestinal microorganisms in man, was investigated by a radiorespirometric study and an anaerobic incubation of [U-14C]fructooligosaccharides with feces. About 49% and 55% of the administered radioactivity were detected in expired 14CO2 after 24 and 48h, respectively. In the anaerobic incubation, the saccharides were catabolized to 14CO2 (9.6%), microbial cell constituents (10.4%), and 14C-volatile fatty acid (acetic acid, 24.1%; propionic acid, 20.2%; butyric acid, 11.4% and valeric acid, 2.2%). Complemental interpretation of the two studies allowed quantitation of the catabolic pathway of fructooligosaccharides in man, and utilization of the oligosaccharides was estimated to be 1.5kcal/g.
Activities of glutathione linked enzymes in red blood cells and concentrations of other free radical scavengers in red blood cells and in plasma were assayed in patients with myelodysplastic syndromes (MDS). Glutathione peroxidase (GSH-Px) activity, concentrations of both reduced glutathione and oxidized glutathione in red blood cells, and lipid peroxide levels in plasma were all significantly increased in MDS patients. Levels of other free radical scavengers in plasma (total vitamin B2, FAD, and coenzyme Q10), however, were decreased. The data suggest that MDS patients may have been exposed to free radicals, and may be hypersensitive to the oxygen intoxication.
Plasma retinol and α-tocopherol concentrations in vitamin supplemented and unsupplemented multiple sclerosis patients were investigated. The unsupplemented group had a plasma α-tocopherol level of 5.5mg/liter. In spite of a similar vitamin A intake the plasma retinol level of the low intake group was less than that of the controls selected from the general population. Increased supplementation was effective in raising the plasma concentrations of these fat-soluble nutrients but not in direct proportion to intake.
Serum lipids, cholesterol, all-trans retinol, and α-tocopherol in multiple sclerosis patients were investigated before and after hyperbaric oxygen therapy. The treatment was carried out in a multiplace chamber for 60min under a pressure of 2.88atm and 100 percent oxygen concentration. The patients had received hyperbaric oxygen weekly for the first month and monthly thereafter for 1 year. There were no significant differences between the initial and final values of α-tocopherol, total lipids, all-trans retinol, and total cholesterol; neither was there any change in the α-tocopherol/lipid or the α-tocopherol/cholesterol ratios.