Toshikazu Takahashi

Adrenoleukodystrophy without adrenal insufficiency and its magnetic resonance imaging

SummaryFatty acids of plasma and erythrocyte membrane sphingomyelin were determined by gas chromatography-mass spectrometry in adrenoleukodystrophy (ALD) without adrenal insufficiency. Mass chromatogram tracing with the ion at m/z 143 [(CH2)6 COOH3]+ showed increases of saturated very long chain fatty acids in plasma and erythrocyte membrane sphingomyelin in ALD. The C26:0/C22:0 ratios in plasma were 0.121, 0.057 and 0.007 in cases 1 and 2, and a control subject, respectively. The C26:0/C22:0 ratios in erythrocyte membrane sphingomyelin were 0.386, 0.211 and 0.093 in cases 1 and 2 and the control subject, respectively. The demyelinating process of ALD was clearly observed in both the inversion recovery 2100/500 and spin echo 2100/80 scans on magnetic resonance imaging. The magnetic resonance image in case 1 revealed widespread demyelinated lesions, involving almost the entire cerebrum and cerebellum, at 4 years after the onset, while that in case 2 revealed demyelinated lesions mainly limited to parieto-occipital areas at 1 year after the onset.

Transient hyperphenylalaninaemia with a high neopterin to biopterin ratio in urine

A case of transient hyperphenylalaninaemia with a maturational delay of dihydropteridine synthesis is described. With the Guthrie test, the patient showed a blood phenylalanine level of 38 mg dl−1, which had fallen to a normal value without a phenylalanine restricted diet by 3 months of age. The neopterin level and the neopterin to biopterin ratio in the patients urine were very high at 19 days of age. The blood phenylalanine level did not decrease when tetrahydrobiopterin (2.5 mg kg−1) was administered at 19 days of age, while administration of tetrahydrobiopterin (7.5 mg kg−1) at 20 days of age had decreased the blood phenylalanine level to 50% of the preloading level after 24 h. The oral phenylalanine loading test showed the pattern of classic phenylketonuria (PKU) at 15 days of age, but it showed the normal pattern at 1 year 8 months of age.

The effect of a high fat diet on pyruvate decarboxylase deficiency without central nervous system involvement

A nine-year-old Japanese boy with low pyruvate decarboxylase activity in fibroblasts showed no central nervous symptoms except for muscle fatigue. The pyruvate decarboxylase activities in fibroblasts of the patient and two control subjects were 0.407 +/- 0.083, 1.029 +/- 0.137 and 1.607 +/- 0.096 mumoles/g protein/30 min, respectively. The Michaelis-Menten constant (Km) was the same in the patient and controls. There was no inhibitor of pyruvate decarboxylase in the patients fibroblasts. A high fat diet has been given to the patient for five years. At present he does not complain of any kind of muscle fatigue, except after severe exercise. Mental and physiological development of the patient are within the normal ranges. However, trials of orally administered thiamine hydrochloride or thiamine hydrochloride combined with lipoamide did not improve his muscle fatigue.

Lymphocyte phosphorylase kinase activities in the sex-linked form of liver phosphorylase kinase deficiency

Lymphocyte phosphorylase kinase activities were measured in normal controls and in patients with the sex-linked form of liver phosphorylase kinase deficiency. The reaction due to phosphorylase kinase activity in normal lymphocytes (2.7×106 in the reaction tube) was found to be linear within 20–60 min at 30° C. The reaction was directly proportional to the concentration of lymphocytes within 1.5×106–9.0×106, at 30° C for 60 min. The phosphorylase kinase activity in normal lymphocytes, which were pre-incubated at 50° C or 95° C for 1 min, decreased to 60% at 50° C and 10% at 95° C of that after pre-incubation at 0° C for 1 min. The activity of normal controls was 125±23.5 U/1010 lymphocytes. Those of the patients with liver phosphorylase kinase deficiency due to the sex-linked form were 43.5 U in case 1, 54.5 U in case 2, and 51.3 U in case 3, respectively and those of the mothers were within the normal range. These results suggest that phosphorylase kinase in lymphocytes might be form intermediate between liver and muscle phosphorylase kinase.

β-Glucosidase activity in liver, spleen and brain in acute neuropathic gaucher disease

We examined the property of beta-D-glucosidase in normal child liver, spleen and brain tissues and in tissues affected by Gaucher disease using two different kinds of synthetic substrates, 2-hexadecanoylamino-4-nitrophenyl-beta-D-glucopyranoside (HN Glc) and 4-methylumbelliferyl-beta-D-glucopyranoside (MU Glc). HN glucosidase activity was noted only in the particulate fraction of each organ tissues of the normal child, and it was deficient in the tissue affected by Gaucher disease. MU glucosidase activity in the whole homogenate and the soluble fraction showed normal levels for the liver and brain tissue of the Gaucher patient. However, MU glucosidase activity in the particulate fraction, at the vicinity of pH 4.5, for the liver, spleen and brain tissue was deficient in the affected patient. HN Glc was a very easy and useful substrate for the diagnosis of Gaucher disease, but it was not very sensitive. While MU Glc was very sensitive, it was necessary to remove the non-specific beta-D-glucosidase for the diagnosis of Gaucher disease.

N-acetyl-beta-D-glucosaminidase activity in serum, kidney and liver of streptozotocin-induced diabetic rat.

Serum N-acetyl-beta-D-glucosaminidase (NAG) activity in streptozotocin-induced diabetic rats was significantly increased. There was neither a difference in total NAG activity in kidney and liver, nor in optimal pH of NAG in serum, kidney and liver between diabetic and control rats. The ratio of the thermounstable fraction of NAG increased in diabetic kidney and liver, while there was no difference in thermostability of between diabetic and control rats. Isoelectricfocusing of diabetic serum NAG indicated an increase in the neutral form. That of kidney and liver NAG indicated an increase in the acid form. These results may suggest that NAG clearance from the serum is decreased diabetic state.