N-Nitrosodi-n-propylamine induces organ specific mutagenesis with specific expression times in lacZ transgenic mice

The mutagenic and clastogenic effects of N-nitrosodi-n-propylamine (NDPA) in lacZ transgenic mice (MutaMouse) were investigated as a part of the second collaborative study of the transgenic mouse mutation assay by a subgroup of the Mammalian Mutagenesis Study Group, a suborganization of the Environmental Mutagen Society of Japan. Male MutaMouse mice were administered NDPA intraperitoneally at a dose of 250 mg/kg, which is half of the LD(50) of the compound. The clastogenicity of NDPA was examined by the peripheral blood micronucleus test just before and at 24, 48 and 72 h after the treatment. The mutant frequencies in the bone marrow, liver, lung, kidney and urinary bladder were examined by the positive selection method for lacZ kidney. These findings demonstrate that NDPA induces organ-specific mutagenesis with specific expression times, and that the mutagenicity of NDPA in lacZ transgenic mice is consistent with its carcinogenicity.

Positron emission tomography in juvenile Alexander disease

A 13-year-old boy with cervical kyphosis was diagnosed as having juvenile Alexander disease because of the typical MRI findings, abnormally elevated alphaB-crystallin and heat shock protein 27 in the cerebrospinal fluid. Positron emission tomography with 18F-fluorodeoxyglucose demonstrated hypometabolism in the frontal white matter corresponding to the areas with leukodystrophy. However, the overlying gray matter preserved normal glucose metabolism.

Mutational analyses in four Japanese families with X-linked liver phosphorylase kinase deficiency type 1

We analysed the gene of the human alpha-subunit of liver phosphorylase kinase (PHKA2) in four Japanese families with X-linked liver phosphorylase kinase deficiency type 1 by RT-PCR followed by PCR-single-strand conformation polymorphism and direct DNA sequencing. In this study, two novel mutations (Y116D and 2675A-->G) and one mutation previously reported (P1205L) were identified, revealing molecular heterogeneity in Japanese patients. Considering the dissimilarity in phenotype among our patients even with an identical mutation in the PHKA2 gene, it seems that each genetic deficiency in this gene may not be the only factor to determine the clinical heterogeneity in this disease.

Anti-platelet aggregation activity of some pyrazines

This report describes the anti-platelet aggregation activity of 48 pyrazines. Among alkyl- and arylpyrazines tested, 2,3-diphenylpyrazines showed the strongest anti-platelet aggregation activity. Then, various substituents were introduced into the phenyl groups, and the 2,3-bis(p-methoxyphenyl)pyrazine derivatives were consequently found to possess considerably strong inhibitory activity.

Isolation of cDNA encoding the human liver phosphorylase kinase alpha subunit (PHKA2) and identification of a missense mutation of the PHKA2 gene in a family with liver phosphorylase kinase deficiency

X-linked liver glycogenosis (XLG) due to liver phosphorylase kinase (PHK) deficiency is the most frequent liver glycogen storage disease. The affected patients present in early childhood with hepatomegaly and growth retardation. We isolated and determined the structure of human liver alpha subunit of PHK (PHKA2) cDNA. The 3705 base pair open reading frame encodes a polypeptide of 1235 amino acid residues, and the deduced amino acid sequence shows 93 and 68% homology to that of rabbit liver alpha subunit of PHK and human muscle alpha subunit of PHK, respectively. We identified a missense mutation, a valine substitution for glycine at amino acid 193, in the PHKA2 gene of a family with XLG.

The micronucleus assay with mouse peripheral blood reticulocytes using acridine orange-coated slides with triethylenemelamine

A micronucleus assay using mouse peripheral blood and supravital staining with acridine orange (AO) was validated by two laboratories on triethylenemelamine-treated mice. Dose- and time-dependent increases in micronucleated peripheral reticulocytes were observed. This new method can be used as an alternative to the conventional bone marrow micronucleus assay.

MRI of spontaneous spinal cord infarction: serial changes in gadolinium-DTPA enhancement

Spinal cord infarcts are rare. We report serial MRI studies of a patient with a clinically diagnosed spontaneous spinal cord infarct. The usefulness of gadolinium diethylenetriaminepentaacetic acid-dimeglumine (Gd-DTPA) enhancement is also discussed. Serial MRI with Gd-DTPA is useful to diagnose the spinal cord infarction.

Possible essentially of docosahexaenoic acid in Japanese monkey neonates: occurrence in colostrum and low biosynthetic capacity in neonate brains

The importance of mother's milk as a source of docosahexaenoic acid (DHA) in Japanese monkey neonates was investigated. The DHA content in monkey colostrum total lipids was 2.2%, similar to or slightly higher than in humans. A comparison of the biosynthetic capacity of brain microsomes from monkeys of different age (up to 10 years) showed that chain elongation/desaturation of linolenic acid and eicosapentaenoic acid in neonates was significantly less pronounced than in adults. In particular, the formation of DHA, which is the product of delta 4 desaturase, was negligible. These results suggest that milk is an important source of DHA in Japanese monkey neonates.

Micronucleus test with methyl methanesulfonate administered by intraperitoneal injection and oral gavage

The effects of 2 routes of administration, intraperitoneal injection (i.p.) and oral gavage (p.o.), in the micronucleus test were evaluated using methyl methanesulfonate (MMS) and 2 strains of mice (MS/Ae and CD-1). A small-scale acute toxicity study and a pilot micronucleus experiment were carried out first. On the basis of the results obtained, a final micronucleus test was performed at doses of 20, 40, 80, and 160 mg/kg (i.p.) and 40, 80, 160, and 320 mg/kg (p.o.), with a 24-h sampling time. MMS induced micronucleated polychromatic erythrocytes (MNPCEs) in both routes in both mouse strains under the conditions used. At 40 and 80 mg/kg, MMS induced a higher number of MNPCEs by the i.p. route in both strains. A 160 mg/kg MMS dose induced higher numbers of MNPCEs by the p.o. route in MS/Ae mice. The route-related difference with MMS on the basis of mg/kg disappeared when the difference was determined on the basis of a ratio of the LD50. In practice, both i.p. and p.o. routes are acceptable as routes of administration in the micronucleus test using this chemical.

Many isoforms of fast muscle troponin T from chicken legs

Troponin T from fast muscle of chicken legs was found to be composed of about 40 kinds of isoforms by two-dimensional polyacrylamide gel electrophoresis in conjunction with immunoblotting tests with an antiserum to chicken breast muscle troponin T. Almost all of the isoforms were found in the myofibril preparation and troponin preparation from the leg muscle, and they showed complex-forming ability with troponin I and troponin C. These isoforms existed in most of the fast muscle except pectoralis and posterior latissimus dorsi muscles, and they changed in composition during development. The breast muscle troponin T also showed different types of isoforms in the period soon after hatching. Since proteolysis was completely inhibited during two-dimensional gel electrophoresis and since the many isoforms were observed consistently in various muscles of chicken leg, they are most probably products of mRNAs generated by differential gene splicing.

Lipids of liver, kidney, spleen and muscle in a case of generalized deficiency of cytochrome b5 reductase in congenital methemoglobinemia with mental retardation

The lipid compositions of liver, kidney, spleen and muscle in a case of generalized deficiency of cytochrome b5 reductase in congenital methemoglobinemia with mental retardation were analyzed and compared with age-matched controls. The contents of cholesterol and phospholipids (mumol/g) in each organ were within the normal range. Diminished proportions of unsaturated fatty acids were observed in ethanolamine phosphoglycerides (EPG) of the liver. The proportion of linoleic acid decreased to less than half of the normal level in EPG of liver, kidney and spleen.

Adipose fatty acid composition in a case of generalized deficiency of cytochrome b5 reductase in congenital methemoglobinemia with mental retardation

The fatty acid composition of the triglyceride in adipose tissue in a case of generalized deficiency of cytochrome b5 reductase in congenital methemoglobinemia with mental retardation was analyzed and compared with age-matched controls. The proportions of linoleic acid, linolenic acid and arachidonic acid were decreased to less than half of normal level. There was a decrease in total unsaturated fatty acids and an increase in palmitic acid. These results revealed an undeveloped pattern of fatty acid composition in adipose tissue in the patient.

Lipids of myelin, white matter and gray matter in a case of generalized deficiency of cytochrome b5 reductase in congenital methemoglobinemia with mental retardation

The lipid classes and fatty acid compositions of myelin, white matter and gray matter were analyzed in a case of generalized deficiency of cytochrome b5 reductase in congenital methemoglobinemia with mental retardation. When compared with normal data, the percentage of 24:1 was considerably decreased and diminished unsaturation was observed in cerebrosides, whereas the sum of 24:0 and 24:1 was the same as in normals. The ratio of hydroxy fatty acids to total fatty acids in cerebrosides was low. The contents of cholesterol and phospholipids in white matter were reduced to 80% of the normal, whereas cerebroside was reduced to 48% of the normal.

Effects of dietary folate deficiency on developmental increase of myelin lipids in rat brain

Rats were fed a folic acid deficient purified diet from day 12 of gestation throughout the lactational period. Offsprings were fed the same diet after weaning. Control rats were given 170 microgram of folic acid per day per rat supplemented to the same diet, which was fed ad libitum or by pair-feeding. At 3 and 6 weeks of age, myelin was isolated from rat brains. It was found that in comparison with the controls, myelin yield was significantly decreased as well as the brain weight in the folic acid deficient rats at 6 weeks of age. There were no differences of gross composition of myelin, protein, ratio of cholesterol, glycolipids, phospholipids, and total lipid with or without folate deficiency either at 3 or 6 weeks of age. The hydroxy fatty acid composition of myelin lipids in brain was not changed with folate deficiency at 3 or 6 weeks of age. The developmental increase of the percentages of 22:6, 22:4, and 20:1 in nonhydroxy fatty acids of myelin lipids from the folic acid deficient rats were significantly lower at 6 weeks of age in comparison with the controls. The n-3:n-6 ratio in myelin fatty acids from the folic acid deficient rat brains was abnormally low at 3 weeks of age and was not increased at even 6 weeks of age. The implications of these findings are that folic acid may play an important role in desaturation or chain elongation of polyunsaturated fatty acids in the brain of developing rats.

Essential fatty acid deficiency induced by total parenteral nutrition and by medium-chain triglyceride feeding

In hospitalized infants receiving either prolonged total parenteral nutrition without fat or a formula of medium-chain triglyceride, the fatty acid composition of platelet, red blood cell, and plasma lipids was determined. The results showed that the changes in the fatty acid composition occurred not only in plasma but also in platelets and red blood cells, and the decrease in linoleic and arachidonic acid and the concurrent increase in 5,8,11-eicosatrienoic acid were confirmed to be dramatic evidence of essential fatty acid deficiency. There was no effect of essential fatty acid deficiency upon the phospholipid distribution in red blood cells or plasma.

Lipid composition of myelin in multiple sclerosis

Myelin was isolated from histologically normal white matter and plaques from MS patients and from white matter of neurologically normal controls. No difference was found in the total lipid content. There were no detectable deficits in MS myelin of phosphoglycerides, plasmalogens or sphingolipids. Gangliosides and lysolecithin were not detected. Analysis of the fatty aldehyde composition of the phosphoglycerides and the fatty acid composition of the cholesteryl esters, phosphoglycerides and sphingolipids did not show any differences between the normal and MS myelin.