Medium-chain acyl CoA dehydrogenase (MCAD) (acyl-CoA: (acceptor) 2, 3-oxidoreductase, EC 220.127.116.11) deficiency in two patients, MV and AH, was examined by use of an anti-MCAD antibody and the cDNA for the enzyme. No MCAD protein was detected by immunoblot analysis in the fibroblast extract from the first patient MV, while it was present, but not catalytically active in the second patient AH. In order to clarify the molecular mechanism of these deficiencies, a cDNA encoding MCAD was isolated from a human placenta cDNA library. The cDNA contained 1, 263 nucleotides of the coding region, 64 nucleotides of the 5′-noncoding region, and 686 nucleotides of the 3′-noncoding region. The level of mRNA for MCAD in the patients was examined by RNA blot analysis with the cDNA as probe, and the results indicate that the patient MV also had the mRNA and that the level of the mRNA in both patients was almost the same as that of the control subject. Thus it seems that the deficiency in the patients is due to a point mutation(s) and that the position of the mutation(s) in the gene of patient MV is different from that of patient AH.
A method for rapid preparation of subfractions of low density lipoprotein (LDL) from the serum of cholesterol-fed rabbits was devised. The method includes three steps: (1) removal of chylomicrons and very low density lipoprotein by ultracentrifugation with a vertical rotor for 1h; (2) separation of LDL subfractions, LDL-1, LDL-2, and LDL-3, by ultracentrifugation with a vertical rotor for 2h; and (3) Fast Protein, Polypeptide, Polynucleotide Liquid Chromatography (FPLC) for purification of these LDL subfractions. The whole procedure of the present method could be completed within 13h. On the basis of size and density distribution, LDL-1 corresponded to intermediate density lipoprotein obtained by the standard sequential floatation method (d=1.006-1.019) from the same serum. Gel electrophoresis, density distribution, and FPLC analysis showed that LDL-1 was contaminated with neither other lipoproteins nor serum proteins. LDL-3 was found to contain LDL obtained by the previously reported method from the serum of a rabbit fed a normal diet. LDL-2 had properties intermediate between those of LDL-1 and LDL-3.
The chemotactic peptide fMet-Leu-Phe induced specific protein phosphorylation of human polymorphonuclear leukocytes. The major phosphorylated protein was observed to have a molecular size of 64kDa judged from sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The phosphorylated 64-kDa protein was definitely detected from 45s after fMet-Leu-Phe treatment and then increased in quantity with the incubation time. When the 64-kDa protein was phosphorylated, its pI decreased, as demonstrated by two-dimensional electrophoresis. On the other hand, sensitivity of polymorphonuclear leukocytes to cytochalasin B remained at a low level for 30s after fMet-Leu-Phe treatment when it was determined by release of myeloperoxidase and O2- production. But the cytochalasin B-dependent myeloperoxidase release and O2- production increased with the extension of the incubation time in the presence of fMet-Leu-Phe, reaching their maximal levels over a 180-300s period. Furthermore, fMet-Leu-Phe also induced a temporal increase in the intracellular CAMP level with its peak at 15s, which thereafter returned to its initial level; whereas no major change was observed in the level of cGMP. Phosphorylation of the 64-kDa protein was slightly enhanced with dibutyryl-cAMP, but not with dibutyryl-cGMP. 12-O-Tetradecanoylphorbol 13-acetate and A23187 also stimulated phosphorylation of this protein with slow responses. These results suggest that phosphorylation of the 64-kDa protein is related to the cytochalasin B-dependent release of enzymes from and O2- production by polymorphonuclear leukocytes.
Plasma and tissue lipid peroxide levels were examined in spontaneously diabetic Chinese hamsters (CHA colony) to elucidate the relationship between lipid peroxides and diabetes mellitus. The animals were divided into three groups: group A with severe diabetes, group B with moderate diabetes and group C without diabetes. The plasma lipid peroxide level of groups A and B was significantly higher than that of group C. This level showed significant positive correlations with fasting plasma glucose and lipid levels, but a significant negative correlation with the non-fasting plasma insulin level. The lipid peroxide contents of the liver and aorta of group A were significantly higher than those of group C. We conclude that the plasma lipid peroxide level increases in these diabetic hamsters with the advance of hypoinsulinemia, hyperglycemia, and hyperlipidemia and that its content in the liver and aorta is also increased in these animals.
The inner wall of the carotid of spontaneously hypertensive rats was severely disturbed by anoxia treatment, whereas that of the control carotid of the Wistar-Kyoto rat was not affected, as judged from observations by scanning electron microscopy. Fourier transform infrared measurement of carotid in situ revealed that the membrane fluidity was increased in the hypertensive rat carotid subjected to anoxia, but not in the Wistar-Kyoto rat carotid. This finding suggests that the abnormal response of membrane lipid phase of the spontaneously hypertensive rat carotid to anoxia might trigger the disturbance of the inner wall.
Effect of vitamin A deficiency on urolithiasis was investigated in male weanling rats. Two groups of rats, namely, experimental and pair-fed controls, were maintained on a basal calculogenic diet high in calcium (9g/kg diet) for 12 weeks. The diet of the experimental group was devoid of vitamin A. At the end of this period urine was collected for two days and the animals were sacrificed subsequently. Rats in the vitamin A-deficient group exhibited very dense calcium oxalate crystalluria. The incidence and weight of bladder stones were remarkably higher in these rats as well. Besides bladder calculi the experimental group developed renal calculi also. While urinary excretion of calcium, oxalate, and uric acid were increased in the vitamin A-deficient animals, excretion of glycosaminoglycans, citrate, and phosphate were decreased. Inhibitory activity of urine towards the growth of calcium oxalate crystals was markedly reduced in them also. A significant positive correlation between urinary glycosaminoglycans and inhibitory activity of urine and a significant negative correlation between uric acid and inhibitory activity were observed. Subsequent correction of vitamin A deficiency normalized most of the above abnormalities. Involvement of vitamin A deficiency in calculogenesis was clearly demonstrated, and the underlying mechanisms were elucidated in this study.
In our study of potassium levels in normal pregnant Nigerian women the mean serum potassium concentration was 5.80±1.50mEq/liter (pooled data of all pregnant women irrespective of gestational age). This level decreased with maternal age and parity and increased progressively with gestational age. The value recorded in the first trimester was 4.50±0.35mEq/liter, which increased to 5.85±0.80mEq/liter in the second trimester and to 6.00±0.60mEq/liter in the third trimester. Apart from other factors that affect serum potassium levels during pregnancy, the social status of the pregnant women was also found to influence the values, rising from 5.50±0.10mEq/liter in the case of farmers to 6.00±0.20mEq/liter in the case of civil servants. The nutritional implications of this study with respect to proper fetal development is discussed.
Plasma cholesterol, triglyceride, phospholipid and fatty acid fractions of healthy pregnant women were investigated and found to rise significantly in the first trimester, followed by a fall in the second and subsequent rise again in the third trimester or near term (p<0.01). Of all the lipid classes determined, the phospholipid fraction had the highest increase (94%) at near term and had the highest concentration in the plasma (350.85±22.85mg/100ml). This was followed by free fatty acid (64%; 78.52±13.66mmol/100ml), total cholesterol (58%; 293.00±18.58mg/100ml), and triglyceride (38%; 203.00±13.40mg/100ml) fractions. Whereas phospholipids and triglyceride levels increased with parity, total cholesterol and fatty acid levels showed appreciable decreases with multiparity. There was no significant correlation between plasma lipid level and body weight or age of the pregnant women (p>0.05). Social class, an index of nutritional status, was found to be highly correlated with plasma lipid levels (p<0.05; r=+0.842). The significance of this to fetal quality and survival is discussed.
The effects of a dietary intake of gamma-linolenic acid 18:3 n-6 (GLA) on blood lipids and phospholipid fatty acids were studied in 25 healthy men. The study was conducted over 4 one-month periods during which the subjects maintained their usual diet of about 2, 780kcal per day consisting of 54.4% carbohydrates, 13.5% proteins, and 32.1 lipids, the last of which included 13% in the form of vegetable oils (40g) and 328mg of cholesterol. The vegetable oil, the only parameter which was varied during the study, was soybean oil during the 1st and 4th periods, not providing GLA, and rapeseed oil and evening primrose oil in the proportion of 2:1 during the 2nd period, providing 1.1g of GLA per day, and 1:1 during the 3rd period, providing 1.6g of GLA per day. The intake of other fatty acids was maintained as constant as possible throughout the study. The administration of GLA was accompanied by a dose-dependent reduction in LDL cholesterol (-10% with 1.1g of GLA and -25% with 1.6g of GLA) and a significant increase in HDL cholesterol (+7 and +9%, respectively). Triglycerides, phospholipids, and apoprotein B did not vary significantly, while apoprotein AI was markedly increased (+20 and +20%, respectively). In terms of the serum phospholipid fatty acids, the GLA ingestion was also accompanied by dose-dependent decrease in linoleic acid and increases in all its derivatives. Heterogeneous variations were observed in the n-3 derivatives: the 20:5 n-3 was decreased but the 22:5 n-3 and the 22:6 n-3 remained stable. A decrease was observed for the 18:0 and the 24:0, while the 18:1 n-9 was increased. These results indicate that dietary gamma-linolenic acid is more efficient in reducing serum LDL cholesterol than dietary linoleic acid.