Intestinal lactase polymorphisms and dairy foods.
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Animals↗
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Disaccharidase-deficient animals have normal ultrastructure of intestinal brush border membranes.
The intestinal disaccharidases, lactase, sucrase-isomaltase complex, and glucoamylase are proteins intimately associated with the brush-border membrane of the epithelial cell. These three enzyme activities are found in the intestine of the adult rat; lactase and glucoamylase activities are primarily associated with the intestine of the infant rat. Only glucoamylase and isomaltase activities are detected in the intestine of the California sea lion, Zalophus californianus. The activities of these enzymes are detected only in villus cells, and not in crypt cells. We have carried out electron microscopic studies of negatively stained brush-border preparations of intestinal crypt and villus cells; from the intestine of the 10-day-old rat and from that of the California sea lion. The density of the knob-like structures protruding from the brush-border membranes was not significantly different in any of these preparations. The diameter of the knobs on the preparations from crypt cells was smaller than the diameters of the knobs found on membranes prepared from the other sources. These data are discussed in terms of the relationship between the presence of knob structures and disaccharides activities associated with the brush-border membranes.
Animals↗
The genetic defect in the various types of human beta-galactosidase deficiency.
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Animals↗
Biochemical, genetic, psychometric, and neuropsychological studies in heterozygotes of a family with globoid cell leucodystrophy (Krabbe's disease).
Detection of a patient suffering from Krabbe's disease led to carrier screening in his family. Determination of galactosylceramide beta-galactosidase activity revealed the occurrence of two different alleles among the carriers of the same family. Heterozygotes and their noncarrier relatives were studied using psychometric and neuropsychological tests under blind conditions. It was found that compared to seven adult noncarrier relatives 19 adult carriers differ significantly in their general IQ and some subtests of the Wechsler Intelligence Scale for adults (WISA), including spatial cognition. Reaction times were significantly slower in the carriers with enzyme activity below 25% of the control values. Most of the carriers of this family have had myopia since early childhood.
Adult↗
Distribution of the lactase phenotypes in the population of the Democratic Republic of the Sudan.
The distribution of the adult lactase phenotypes, lactose absorption, and lactose malabsorption, was determined by a field version of the hydrogen breath test for disaccharide absorption in a sample of 563 subjects residing in the Democratic Republic of the Sudan. Relatively high proportions of lactose absorption were found in the northern nomadic groups who rely heavily on dairying for their livelihood. Residential Nile valley populations revealed intermediate frequencies of the two phenotypes whereas the negroid populations of the south exhibited a high prevalence of lactose malabsorption irrespective of their economic status with respect to agriculture and dairying. The frequency of the "hypolactasia allele" ranged between 0.6 and 0.87 in the major regional groups.
Adult↗
beta-Galactosidase-neuraminidase deficiency in adults: deficiency of a freeze-labile neuraminidase in leukocytes and fibroblasts.
4-methylumbelliferyl neuraminidase activity was studied in fibroblasts, leukocytes, and frozen tissues from adult patients with beta-galactosidase-neuraminidase deficiency and specific clinical manifestations. This enzyme was almost completely deficient in fibroblasts, but the residual activity was relatively high (20% of the control mean) in the leukocytes from the patients. The frozen liver from one patient showed the enzyme activity as high as controls. This enzyme consisted of two components, freeze-labile and freeze-stable, and it was demonstrated that only the labile enzyme was deficient in fibroblasts and leukocytes. The apparently normal activity of neuraminidase in frozen autopsy tissues of a patient may be explained by the loss of the labile component in control tissues after a long-term freezing. The neuraminidase activity was variable in parents and no definite conclusion was drawn on the hereditary nature of the disease.
Brain↗
The two human lactosylceramidases and their respective enzyme activity deficiency diseases: inhibition studies using p-nitrophenyl-beta-D-galactoside.
Total lactosyl ceramide beta-galactosidase (LC) activity from normal and pathologic human leukocytes and tissues was subdivided into LC I (EC 3.2.1.46) and LC II (EC 3.2.1.23) activity by means of specific inhibition of LC II with 5 mM p-nitrophenyl-beta-D-galactoside (Ki = 1.5 mM). In globoid-cell leudodystrophy, inhibition of total LC was nearly complete (only LC II is active), whereas in GM1-gangliosidosis Type 1, very little inhibition was found (only LC I is actict). Total LC activity was not significantly low in either of the diseases, which have different genetic origins. The ratio of LC I to LC II activity may display remarkable genetic variation in normal probands.
Child↗
Morquio-B disease, spondyloepiphyseal dysplasia associated with acid beta-galactosidase deficiency. Report of three cases in one family.
Two sisters and one brother, all with normal intelligence and no evidence of neurological abnormality, present progressive spondyloepiphyseal dysplasia, stunted growth, corneal opacities, and increased keratansulfaturia. Cultured skin fibroblasts from one of the children showed a remarkable deficiency of acid beta-galactosidase in association with normal activities of N-acetylgalactosamine-6-sulfate sulfatase and sialidase. Acid beta-galactosidase was also deficient in leukocytes of two children. Leukocytes of the parents exhibited intermediate activities, which suggests the primary nature of beta-galactosidase deficiency. Patients with MPS IV-B may be severely affected.
Adolescent↗
14CO2 in breath.
The diagnosis of metabolic disorders can be made by detecting 14CO2 in the breath. This is possible because 14CO2 can label any organic compound without any deteriorations in the nature of the compound. This type of analysis is dependable, noninvasive and simple to perform with a scintillation counter.
Aminopyrine↗
Evidence against nutritional adaption of tolerance to lactose.
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Alleles↗
Adult type mucolipidosis with beta-galactosidase and sialidase deficiency. Histological and biochemical studies.
A case of adult type mucolipidosis with beta-galactosidase and sialidase deficiency is described. This patient, a woman aged 20, had mental retardation, macular cherry-red spots, corneal clouding, gargoyle-like face, cerebellar ataxia, myoclonus and convulsions beginning at the age of 14. Bony deformities, vacuoles in the peripheral lymphocyte and foamy cells in the bone marrow were also noted. Biopsy study of the sural nerve and vermiform appendix disclosed many vacuoles in almost every kind of cells, although the accumulated substance in these vacuoles could not be characterized histochemically or ultrastructurally. Deficient leukocyte beta-galactosidase and sialidase were confirmed. There was increased urinary sialoglycopeptide and increased siliac acid and hexosamine in the glycoprotein of lymphocytes. Leukocytes sialidase activites of the parents were 30 to 50% of the control values. These results suggest a genetic defect of sialidase.
Adult↗
A case of neuraminidase deficiency associated with a partial beta-galactosidase defect. Clinical, biochemical and radiological studies.
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.
Cells, Cultured↗
Clinical heterogeneity in infantile galactosialidosis.
A new case of infantile galactosialidosis is presented. The condition was diagnosed when the patient was 4 months of age and she died at 20 months. She exhibited some of the symptoms of classical infantile galactosialidosis but no corneal clouding, cherry-red macular spot or limitation of joint mobility. Sonographic examination showed large kidneys and thickened cardiac septa, two symptoms as yet undescribed in this disorder. Urinary oligosaccharide analysis gave grossly pathological results and subsequent fibroblast enzyme analysis showed a deficiency of alpha-neuraminidase and beta-galactosidase. The patient's clinical features are compared with the few cases so far described in the literature.
Female↗
Infantile cardiomyopathy and neuromyopathy with beta-galactosidase deficiency.
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Cardiomyopathies↗
Lactose absorption and malabsorption in healthy German children: improved phenotypic resolution by simultaneous determination of breath hydrogen and carbon dioxide.
A total of 124 apparently healthy German children aged 8 to 10 years were examined for lactose absorption employing the breath hydrogen test with multiple breath collection. Analysis of the maximal change of breath hydrogen concentration (delta maxH2) 110 and 150 min after a lactose load of 30 g failed to yield a bimodal distribution separating lactose absorbers and malabsorbers as observed in adults. Comparison with an adult control group of 120 subjects showed that the mean CO2 concentration was significantly lower and the coefficient of variation was considerably higher in the breath samples of the children. The difference between the highest and the lowest CO2 concentration in the three samples obtained from each individual was also significantly higher in the group of children. Normalizing the children's H2 concentration values to the mean CO2 concentration in the total group (3.04%) yielded a bimodal distribution of the delta maxH2 values. Of 124 children, 18 were identified as lactose malabsorbers. The 14.5% frequency is similar to that observed in German adults.
Air↗
A severe infantile sialidosis (beta-galactosidase-alpha-neuraminidase deficiency) mimicking GM1-gangliosidosis type 1.
We observed a 3-month-old Japanese female infant with severe psychomotor retardation, coarse facial appearance, hepatosplenomegaly, and dysostosis multiplex. Only beta-galactosidase was found to be deficient when the routine lysosomal hydrolase assay was performed on the patient's lymphocytes at 6 months of age. At first GM1-gangliosidosis type 1 seemed the most likely diagnosis. Later, however, additional studies (hydrolase assay in cultured skin fibroblasts, urinary oligosaccharide analysis, genetic complementation study, etc.) revealed that biochemical data of this case were in agreement with those of severe infantile sialidosis. The only important exception was that alpha-neuraminidase in the patient's lymphocytes showed normal activity but abnormal pH dependence toward 4-methylumbellyferyl substrate. In addition, a severely damaged kidney suggested that his case may be classified as a unique type of severe infantile sialidosis (possible nephrosialidosis). These observations stress the importance of careful biochemical diagnosis of a case with GM1-gangliosidosis type 1 phenotype.
Diagnosis, Differential↗
Suitability of the azocoupling reaction with 1-naphthyl-beta-D-glucoside for the histochemical demonstration of lactase (lactase-beta-glucosidase complex) in human enterobiopsies.
The suitability of the simultaneous azocoupling reaction with 1-naphthyl-beta-D-glucoside and hexazonium-p-rosanilin in the detection of the activity of lactase (or lactase-beta-glucosidase complex) in jejunal biopsies of patients with various forms of the malabsorption syndrome was tested. Results were compared with those obtained with the indigogenic method using 4-Cl-5-Br-3-indolyl-beta-D-fucoside which is the method of choice. Both methods gave identical results as far as the relative intensity of the brush border staining was concerned. The azocoupling method applied in unfixed cold microtome sections can be recommended for the routine diagnostics of the malabsorption syndrome when the indolyl substrate is not available.
Adult↗
Urinary oligosaccharide screening in patients with beta-galactosidase deficiency.
Following ion-exchange chromatography and subsequent thin-layer chromatography, 3 peculiar oligosaccharide excretion patterns were distinguished in 3 patients with beta-galactosidase deficiency. Each patient differed clinically and it is proposed that this method may be of use in characterizing various forms of beta-galactosidase deficiency.
Child↗