beta-Galactosidase deficient-type mucolipidosis: a complementation study of neuraminidase in somatic cell hybrids.
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Biomedical subjects
Publications and source records attributed to H Yabuuchi.
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A new and simple assay method for lysosomal hydrolase in a single cultured skin fibroblast is described. Using 4-methylumbelliferyl-glycosides and ordinary laboratory equipment, the activity can be measured with the highest sensitivity of 0.5 pmol of 4-methylumbelliferone released from the substrates. Two systems were compared and the methods described proved reliable for the diagnosis of several variants of beta-galactosidase deficiency.
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Neuraminidase deficiency towards fetuin, 2 leads to 3 sialyllactose and 2 leads to 6 sialyllactose was found in cultured skin fibroblasts from a 10-year-old Japanese girl who exhibits craniofacial dysmorphism, a short neck, vertebral and pelvic deformities and macular cherry-red spots. Neuraminidase deficiency in this case seems the primary enzyme defect because the enzyme activity of her parents was intermediate. In addition, beta-galactosidase in leukocytes and cultured skin fibroblasts from the patient was found to be severely deficient, but could be detected in serum and urine. In the parents, beta-galactosidase activity was normal. There were moderately increased levels of urinary sialic acid-rich oligosaccharides and glycopeptides in the patient. The clinical and biochemical observations suggest that this case is very close to mucolipidosis I.
The seasonal distribution of birth dates of 31 patients with sporadic cretinism due to thyroid dysgenesis was analyzed in Osaka area for 14 years. The incidence was statistically high in the summer months. A hypothesis that some environmental factors such as viral infection may cause the disease is proposed.
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Skin and conjunctival biopsy specimens from fourteen patients with neuronal storage diseases were investigated using an electron microscope. The diseases were Tay-Sachs disease, ceroid-lipofuscinosis (Jansky-Bielschowsky type), Niemann-Pick disease (type B), highly suspected adrenoleukodystrophy, I-cell disease, mucolipidosis of the beta-galactosidase deficient type, Hurler disease, Hunter disease and Morquio disease. This examination provided valuable diagnostic information on some neuronal storage diseases but not on Morquio disease or highly suspected adrenoleukodystrophy. False negative results may sometimes occur using this examination method. However, this examination suggests the usefulness of skin and conjunctival biopsy specimens as a diagnostic tool in some neuronal storage diseases.
A case of mucolipidosis II was studied biochemically, nutritionally and immunologically. A possible functional deficiency of T cells was observed, but discrepancy between B cells and immunoglobulin content was not reasonably explained at this moment. There was no basic nutritional problem in this case and it is more likely that his growth retardation was due to frequent episodes of severe respiratory infection because he received adequate calorie intake with low normal basal metabolic rate. Results of enzymatic assays were also presented.
Insulin and glucagon secretion was investigated in ten patients with hepatic glycogenosis, types I and III, in order to understand the relationship between hypoglycemia and pancreatic function. In all patients, both oral glucose tolerance and intravenous arginine infusion tests revealed hypoinsulinemia. Decreased urinary C-peptide levels with standard food intake also supported hypofunction of pancreatic beta cells. On the contrary, the normal secretion pattern of glucagon in both types indicated in the arginine loading test, intact alpha cells in the pancreas. Persistent hypoinsulinism, which is apparently an adaptation to hypoglycemia, could be an important cause of nutritional dwarfism in both types of glycogenosis. The usefulness of the measurement of urinary C-peptide, which evaluates the pancreatic function and provides management for normal body growth, is discussed.
A case of transient hyperthyrotropinaemia was found by mass screening for neonatal hypothyroidism using the paired TSH assay method. The patient was a baby boy born at term after a normal pregnancy who grew without any abnormal signs or symptoms. For the first 7 months after birth, his serum TSH was abnormally high while his total serum T4, T3, and free T4, T3 were within normal limits, exept for slightly low free T4 level at 7 months. The raised serum TSH decreased spontaneously to within normal limits after he was 9 months old.
The breath hydrogen test (BHT) was adapted for use in young infants and children. The diagnostic criterion of sugar malabsorption in the BHT was determined by oral administration of 0.5 g/kg of unabsorbable sugar (lactulose) to 21 healthy infants and children. A maximum increase in breath hydrogen less than 0.05 ml/min per m2 was observed in all subjects. A good correlation between results by the BHT and by the ordinary lactose tolerance test was obtained after oral administration of 2 g/kg lactose to 21 healthy infants and children, 2 congenital lactase-deficient infants, and 7 adults. Using this test, 80 healthy Japanese infants and children (aged between one month and 15 years) and 18 adults were examined for lactose malabsorption after a dose of 1 g/kg lactose. All infants and children under 2-years old absorbed lactose completely. The incidence of lactose malabsorption was 30% in 3-year, 36% in 4-year, 58% in 5-year, and 86% in 6-year-old children, 85% in schoolchildren, and 89% in adults. Thus the incidence of lactase deficiency gradually increases with age from 3 years, and about 90% of all normal Japanese adults are lactase-deficient.
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Four tests for antibody to varicella-zoster (V-Z) virus were compared; these were tests of complement fixation (CF), neutralization (NT), fluorescent antibody to membrane antigen (FAMA) and immune adherence hemagglutination (IAHA). Fifty-two sera from patients with varicella and zoster and from recipients of live varicella vaccine were examined by the 4 tests. The CF test was least sensitive, but the antibody titers by the NT, FAMA and IAHA tests were roughly comparable. The IAHA test was the simplest and fastest to perform, and appeared suitable for routine serological assay to V-Z virus. The correlation between the IAHA antibody titer and susceptibility of individuals to clinical varicella was investigated retrospectively using sera obtained during 2 outbreaks of varicella in an institution for children, where all the unvaccinated children had developed varicella symptoms. Most of the 25 pre-exposure sera from unvaccinated children examined by the IAHA test had tiers of less than 1:2. In contrast, all the 23 sera from vaccinated children who did not develop varicella had detectable antibody titers of 1:2 to 1:64. These results indicate that the IAHA titer reflects the susceptibility or resistance of individuals to clinical varicella.
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Somatotropic, thyrotropic, gonadotropic and corticotropic functions in 10 patients with idiopathic hypopituitary dwarfism (IH) were investigated. The patients were divided into two groups: Group I (5 patients) had normal plasma T4 levels, and Group II (5 patients) had T4 levels of less than 4.6 microgram/dl. In Group I three cases had isolated growth hormone (GH) deficiency and two cases had GH and gonadotropin (Gn) deficiencies; in Group II the 5 cases showed multiple anterior pituitary hormone deficiencies. In Group II, the plasma thyroid stimulating hormone (TSH) was 4.1-9.4 muU/ml and the response to thyrotropin releasing hormone (TRH) was greatly delayed and prolonged, with a maximum after 120 min instead of 15 min. The basal prolactin (PRL) level in Group II was 12-31 ng/ml, which was significantly higher than normal (P less than 0.001). In 4 cases in Group II, the plasma cortisol level increased 120 min after the infusion of lysine-vasopressin, whereas oral administration of metyrapone and hypoglycemia induced by insulin did not increase the plasma cortisol levels. From these findings it is concluded that hypothalamic lesions caused the pituitary hormone deficiencies in 4 Group II cases, and Group I may tentatively be differentiated from Group II by T4 determinations.
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A method is described for the detection of abnormal oligosaccharides in a small (5 ml) volume of urine, employing filtration on a Bio Gel P-6 column, determination of neutral sugar and bound sialic acid, and determination of creatinine content. With this method increased urinary excretion of sialic acid-rich oligosaccharides has been detected in nine patients with mucolipidoses (five cases of mucolipidosis II and four patients of mucolipidosis, with beta-galactosidase deficiency). The filtration patterns of oligosaccharides in mucolipidoses were clearly distinguishable from those in other inborn errors of metabolism. Total excreted oligosaccharides were increased 5--30-fold in these patients; mucolipidosis II, 640--1350 microgram neutral sugar/mg creatinine; control 54 +/- 20 microgram neutral sugar/mg creatinine. The oligosaccharides consisted of three sialic acid-rich fractions and were common in both types of mucolipidosis. Our data indicate that hypersialyoligosacchariduria is the main biochemical feature of both types of mucolipidosis.