There is a strong need for techniques to assess human muscle protein synthesis by repeated sampling to follow the course of physiological and pathophysiological events affecting protein metabolism. Here protein synthesis in human skeletal muscle was studied by the incorporation of [14C] leucine into protein in a cell-free system. Healthy male volunteers (n=20) received a 6-h infusion of either saline, adrenaline, or a triple-hormone combination of adrenaline, cortisol, and glucagon after an overnight fast. Percutaneous muscle biopsies were taken before and after the infusion. The in vitro incorporation rate per mg of DNA decreased by 11.2±3.6% in the adrenaline group (p<0.05) and by 12.3±3.4% in the triple-hormone group (p<0.01) as compared with the basal preinfusion values. No significant change was seen in the control group. The technique presented offers several advantages and the use of it is advocated in combination with other methods to cover several aspects of muscle protein biosynthesis.
In rat liver microsomes lipid peroxidation was found to be induced by chinoform-ferric chelate either in the presence or absence of NADPH, indicating the occurrence of both electron transfer-dependent and -independent peroxidation of microsomal lipids. In comparison with the case of ADP-ferric chelate, chinoform-ferric chelate gave a greater degree of electron transfer-independent lipid peroxidation. Either ferric ions or free chinoform induced little or no lipid peroxidation in the microsomes. Chinoform-ferric chelate-induced microsomal lipid peroxidation that leads to biomembrane damage was discussed in relation to the pathogenesis of subacute myelo-optico-neuropathy (SMON).
In this study, we verified the hydroxyl radical-scavenging activity (OH-SA) of slow-acting anti-rheumatic drugs (SARD's) and compared it with that of other .OH-scavengers such as dimethylsulfoxide (DMSO), glucose, albumin, and ethanol. For this purpose, we employed the electron spin resonance/spin trapping method in a cell-free system using two different concentrations of the spin trap 5′5′-dimethyl-1-pyrroline-N-oxide (DMPO). The use of two levels of DMPO concentrations made it possible to separate the true OH-SA of SARD's from the direct effects of SARD's on the Fe/H2O2.OH-generating system, which can cause false values for OH-SA. The OH-SA was stronger in the following order: D-penicillamine (D-pen)>bucillamine>lobenzarit disodium (CCA)>DMSO>5-amino-salicylic acid (5-ASA)>albumin=acetyl-5-aminosalicylic acid>glucose>sulfasalazine (SASP)>ethanol. However, D-pen, CCA, 5-ASA, and albumin interfered with the Fe/H2O2.OH-generating system. Auranofin and metabolites of SASP such as sulfapyridine and acetyl-sulfapyridine had no OH-SA in the cell-free system. None of the SARD's had a significant OH-SA at the concentrations reported in the plasma from patients taking these medications. Therefore, it is unlikely that SARD's act as true .OH-scavengers in the plasma. At sites of inflammation, however, SARD's may contribute to the scavenging of .OH produced as in the case of 5-ASA, since its concentration has been reported to be much higher in special sites such as the distal lumen of the bowel.
By use of a hybridization technique between BALB/c myeloma cells and spleen cells of mice immunized with rat anionic trypsinogen purified from rat pancreas, four monoclonal antibodies against this protein were produced. These monoclonal antibodies exhibited different inhibitory effects to anionic trypsinogen enzyme assay with benzoyl-L-arginine-p-nitroanilide hydrochloride as a substrate. Several sandwich enzyme-linked-immunosorbent-assays (ELISA's) were produced with different combinations of two monoclonal antibodies. One ELISA showed almost the same reactivity between anionic trypsinogen and anionic trypsin inactivated with an active site-specific reagent. Another ELISA detected anionic trypsinogen specifically, and the cross-reactivity of rat α1-protease inhibitor-bound anionic trypsin and inactivated anionic trypsin were 1.6% and about 4%, respectively. Both ELISA's showed less than 1% cross-reactivity with rat cationic trypsinogen purified from the pancreas.
Two monoclonal antibodies that react with epitopes on the α1-protease inhibitor moiety of rat α1-protease inhibitor-bound anionic trypsin were generated in mice immunized with the complex. They showed high specificity for the complex in comparison with the free α1-protease inhibitor. By use of these monoclonal antibodies and another monoclonal antibody that reacts with an epitope on the anionic trypsin moiety of α1-protease inhibitor-bound anionic trypsin, we established immunoradiometric assays that are specific for the complex. These immunoassays did not give positive results with either free anionic trypsinogen or α1-protease inhibitor. The immunoradiometric assays were applicable to quantification of α1-protease inhibitor-bound anionic trypsin in rat sera, and we found that the mean half-life of the complex in the circulation was 140±16.6min (mean±SD)(n=7). Sandwich enzyme-linked immunosorbent assays were also tried. However, they did not give enough specificities to quantify the complex in the rat sera.
A wide range of studies, extending from experimental animals to controlled clinical trials and epidemiological findings, have led to the belief that a dietary imbalance of zinc (Zn) and copper (Cu) may be a factor in the etiology of coronary heart disease (CHD). We measured the levels of plasma Cu and Zn in 43 normal, 66 hypertensive, and 32 non-insulin-dependent diabetic subjects and compared the results with plasma levels of lipids, lipoproteins, lipase activity, platelet aggregation, age and body mass index (BMI) in all these subjects in order to understand the relationships among these variables. There was no significant change in the plasma levels of Cu, Zn, and Cu/Zn ratios in the hypertensive and diabetic patients as compared with the normal controls. Partial correlations by age and BMI showed a significant positive association between plasma Cu and plasma Zn and Cu/Zn ratio in all three study groups. Partial correlations made by adjustment for interrelated factors were also calculated for all three groups. The results thus obtained did not show any significant correlations between plasma Cu or Zn and the other metabolic variables for the diabetic group. The normal group showed a significant inverse correlation between plasma Cu and plasma lipase activity or platelet aggregation, whereas the hypertensive group showed an inverse correlation between plasma Cu and platelet aggregation only. Although extreme experimental dietary variations of Cu and Zn have been shown to influence plasma lipid and lipoprotein levels affecting CHD, we could find no other statistically significant correlations between these trace elements and the coronary risk factors in all three study groups. Therefore, we believe that plasma levels of these trace elements are of doubtful value as indicators of the coronary atherosclerosis risk in our population where the dietary intake of these trace elements seems to be normal.
The relationship between habitual milk intake and levels of serum lipids and their apoproteins, serum cholesterol, and triglycerides and their apoproteins was investigated in 119 male inhabitants in a rural coastal area in Japan. Subjects were divided into three groups according to their daily milk intake, i.e., small (S) (0-60ml/day), medium (M) (61-200ml/day), and large intake (L)(over 200ml/day). Among the normolipidemic subjects, the obesity index in the L group was higher than that in the S group. Total cholesterol, LDL-cholesterol, and apoB concentrations were also significantly higher in the L group than in the S and M groups. In the hypercholesterolemia group, obesity index, total cholesterol, triglyceride, and apoE tended to be higher; and apoA-I and apoB were lower in the L group than in the S group. The subjects in the L group of hypercholesterolemia tended to take in more confectionery, more fish, less vegetables, and less fungi as compared with those in the S group. As a result, the subjects with daily habitual milk intake appear to consume foods that promote obesity, such as those popular in the United States of America and Europe, especially the subjects in the hypercholesterolemia group. The quality and quantity of foods with 200ml of daily milk intake should be selected carefully for hypercholesterolemic Japanese.
In an attempt to ascertain the relative utilization of hydrogenated fats with different melting points, we conducted studies on healthy male volunteers maintained on a diet containing peanut oil (control) or hydrogenated fats melting at 37°, 41°, or 45°C. The results indicated a significantly higher excretion of fecal fat during the ingestion of the fat melting at 45°C. During these dietary regimen, serum triglycerides as well as serum cholesterol tended to increase with an increase in the melting point of the dietary fat. Fatty acid profile of serum lipids showed a decreasing trend in the concentration of linoleic acid (18:2) and an increase in that of arachidonic acid in response to ingestion of high-melting point fat. These investigations point to the fact that high-melting point hydrogenated fats are not only poorly absorbed but also influence fatty acid metabolism. These results are discussed in the light of trans fatty acids of dietary fats.