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Results for “Lactose Intolerance”

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PubMed1978

Lactosyl ceramidosis: deficient activity of neutral beta-galactosidase in liver and cultivated fibroblasts?

Neutral beta-galactosidase was partially purified from liver of normal controls, a patient with Niemann-Pick disease type A and the previously described patient with lactosyl ceramidosis using Concanavalin A-Sepharose adsorption and Sephadex G-100 gel filtration. The partially purified fractions were essentially free of galactosyl ceramide beta-galactosidase and GM1 beta-galactosidase activities. The normal and Niemann-Pick fractions were found to hydrolyze lactosyl ceramide, in the presence of sodium taurodeoxycholate, at a pH optimum of 5.6 as well as aryl beta-galactosides and aryl beta-glucosides at pH 6.2. The corresponding fraction from the lactosyl ceramidosis liver contained only 1--4% of the normal activity towards artificial substrates and lactosyl ceramide. Cross-reacting material identical to the normal was demonstrated in this fraction with antiserum raised against purified neutral beta-galactosidase, but no activity was observed in the precipitin line when stained with naphthol AS-LC-beta-galactoside or naphthol AS-LC-beta-glucoside. A similar deficiency of neutral beta-galactosidase activity was demonstrated in cultivated fibroblasts of the patient with lactosyl ceramidosis. Following adsorption on Concanavalin A-Sepharose and anti-GM1 beta-galactosidase antibody-Sepharose conjugates and chromatography on DEAE cellulose, fibroblast lysates from the patient exhibited 3% of normal activity towards 4-methyl-umbelliferyl beta-glucoside at pH 6.2 and 12% of normal activity towards lactosyl ceramide at pH 5.6. These data suggest that neutral beta-galactosidase may have an in vivo role in the cleavage of lactosyl ceramide and that a deficiency of this activity may be related to the lactosyl ceramide accumulation observed in the patient with lactosyl ceramidosis.

Cells, Cultured↗
PubMed1979

Neuraminidase in mucolipidoses: normal activity in frozen autopsy tissues from three patients with I-cell disease and adult beta-galactosidase deficiency.

Neuraminidase was assayed in the frozen autopsy tissues from three patients with I-cell disease and an adult patient with cherry-red spots, myoclonus, cerebellar ataxia and beta-galactosidase deficiency. Both diseases showed normal neuraminidase activity toward neuramine lactose and fetuin in cerebral gray matter, liver and kidney. These results suggest that the neuraminidase deficiency is limited only to some tissues and that this biochemical abnormality is not caused by a primary genetic mutation in these diseases.

Adolescent↗
PubMed1982

Km defect in neuraminidase of dysmorphic type sialidosis with and without beta-galactosidase deficiency.

Kinetic studies of 4-methylumbelliferyl neuraminidase activity were carried out in cultured skin fibroblasts from patients with various disorders of neuraminidase deficiency. Cell extracts from two patients with dysmorphic type sialidosis of infantile onset, with isolated deficiency of neuraminidase activity, and three patients with dysmorphic type sialidosis of juvenile onset, with combined deficiency of neuraminidase and beta-galactosidase activities, demonstrated 7-12 times higher apparent Km values than those of normal controls (1.0-1.5 mmol/l as compared with 0.12-0.15 mmol/l). The apparent Ki values for N-acetylneuraminic acid and colominic acid were also increased in the dysmorphic type (7-15 and 7-11 times the normal values, respectively). In contrast, in the normomorphic type, normal apparent Km and Ki values were found for 4-methylumbelliferyl neuraminidase activity in fibroblasts from one patient with isolated neuraminidase deficiency and two patients with combined deficiency of neuraminidase and beta-galactosidase. The altered kinetics in the dysmorphic cases indicates a primary defect in neuraminidase with a secondary deficiency of beta-galactosidase in patients with combined deficiency. It is not clear if the primary defect in the normomorphic cases involves a defect in neuraminidase other than a Km defect or if neuraminidase or both neuraminidase and beta-galactosidase deficiencies are secondary to another defect as yet undetermined.

Cell Line↗
PubMed1982

Radioassay method of neuraminidase towards N-acetylneuraminosyl hexasaccharides.

We devised a sensitive method to assay for neuraminidase activities towards alpha-(2 leads to 3)-N-acetylneuraminosyl hexasaccharide and alpha-(2 leads to 6)-N-acetylneuraminosyl hexasaccharide, which were isolated from the urine of a patient with adult sialidosis with partial deficiency of beta-galactosidase. Standard assay conditions for the determination of these neuraminidase activities were established and the radiolabeled reduced derivatives of these substrates were used. The fibroblast neuraminidase had its maximum activity at pH 4.0-4.2, with Km values of 2.22 X 10(-3) and 4.17 X 10(-3) mol/l and Vmax values of 76.9 and 28.6 nmol . mg-1 protein . h-1 towards the 2 leads to 3 isomer and the 2 leads to 6 isomer, respectively. Neuraminidase deficiencies were found in the fibroblasts of adult sialidosis, mucolipidosis II and III. These studies were compared with the neuraminidase activity towards alpha-(2 leads to 3)-N-acetylneuraminosyl lactose.

Carbohydrate Metabolism, Inborn Errors↗
PubMed1989

Assessment of lactose absorption by measurement of urinary galactose.

Individuals with sufficient intestinal lactase hydrolyze ingested lactose to galactose and glucose and these monosaccharides are absorbed. Lactose is not digested completely when intestinal lactase activity is low and the disaccharide is malabsorbed. Breath hydrogen excretion after lactose ingestion is used commonly to diagnose lactose malabsorption. However, no direct tests are currently used to assess lactose absorption. We tested a new method of assessing lactose absorption in 26 healthy individuals. Each subject ingested 50 g of lactose. Participants were evaluated for lactose malabsorption using a standard 3-h breath hydrogen test. In addition, the urinary excretions of galactose, lactose, and creatinine were quantitated for 3-5 h after lactose ingestion. On the basis of breath hydrogen analysis after lactose ingestion, 12 individuals were lactose malabsorbers (defined as a rise in the breath hydrogen concentration of greater than 20 parts per million above the baseline value). The 14 subjects who did not malabsorb lactose by breath hydrogen testing (defined as a rise in the breath hydrogen concentration of less than or equal to 20 parts per million above the baseline value), had significantly more galactose in their urine 1, 2, and 3 h after lactose ingestion than lactose malabsorbers. The ratio of excreted lactose to excreted galactose was significantly decreased in lactose absorbers compared with lactose malabsorbers (p less than 0.001). Determination of the ratio of urinary galactose to urinary creatinine separated lactose absorbers from lactose malabsorbers completely (p less than 0.001). We conclude from this study that the determination of urinary galactose, urinary lactose/galactose ratio, and urinary galactose/creatinine ratio may be used to assess lactose digestion and absorption in healthy adults.

Adolescent↗
PubMed1990

Tolerance for rectosigmoid distention in irritable bowel syndrome.

Two hypotheses were tested: (a) lowered tolerance for balloon distention of the rectosigmoid in patients with irritable bowel syndrome is caused by a psychological tendency to exaggerate the painfulness of any aversive stimulus, and (b) contractions elicited by balloon distention are responsible for pain reports. Tolerance for stepwise distention of a balloon in the rectosigmoid was compared with tolerance for holding one hand in ice water in 16 irritable bowel patients, 10 patients with functional bowel disorder who did not satisfy restrictive criteria for irritable bowel, 25 lactose malabsorbers, and 18 asymptomatic controls. Contractile activity was measured 5 cm above and 5 cm below the distending balloon. Psychometric tests were used to assess neuroticism, anxiety, and depression, and a standardized psychiatric interview was administered. Patients with irritable bowel syndrome had significantly lower tolerance for balloon distention but not ice water, and balloon tolerance was not correlated with neuroticism or other psychological traits measured. Rectosigmoid and rectal motility were also not related to tolerance for balloon distention. Both hypotheses were rejected. A peripheral mechanism such as altered receptor sensitivity may be the cause of distention pain in irritable bowel syndrome.

Colon, Sigmoid↗
PubMed1980

Adult mucolipidosis with beta-galactosidase and neuraminidase deficiencies.

An adult case of mucolipidosis with beta-galactosidase and neuraminidase deficiencies is reported. The patient was a 35-year-old Japanese female with coarse face, lumbar vertebral beaking, action myoclonus, cerebellar ataxia, clouding of the cornea, macular cherry-red spots, hearing loss and vacuolated lymphocytes, but without mucopolysacchariduria. Her clinical symptoms developed at a late age with a slow progression. The enzyme activities of beta-galactosidase were deficient in leukocytes and cultured skin fibroblasts but normal in serum. Sialic acid-rich glycopeptides and oligosaccharides were increased in the urine. Neuraminidase activities toward fetuin, alpha-N-acetylneuraminosyl-(2 leads to 3) lactose and alpha-N-acetylneuraminosyl-(2 leads to 6) lactose were deficient in cultured fibroblasts. It is suggested that the main disturbance in the present case might be the catabolic process of glycoproteins and oligosaccharides due to neuraminidase deficiency.

Adult↗
PubMed1984

Diagnostic role of skin or conjunctival biopsies in neurological disorders. An update.

Updated figures from our reports on electron microscopy of skin or conjunctival biopsies include 256 patients, mostly suffering from lysosomal diseases. Significant morphological data supportive of the diagnosis and additional to enzyme assay (when and if an assay is available for the disorder) were discovered in 95% of the cases. Equivocal or negative data amounted to 5%. The present paper deals with some metabolic disorders which had not been fully dealt with in our previous publications and with an extension of the indications of skin biopsies: adult form and atypical variants of ceroid-lipofuscinoses, galactosialidosis, mucolipidosis IV, infantile neuroaxonal dystrophy, Lafora's disease, cardiomyopathy with generalized accumulation of intermediate filaments and congenital hypomyelination neuropathy. A comparison between biopsy and autopsy material in storage diseases shows that the storage of inclusions does not remain limited to one cell type or to one tissue even if no clinical signs are detectable. This ubiquitous character of the storage can be used for diagnostic purposes. On the other hand, the membrane-bound inclusions are not necessarily similar in all cell types and the search for characteristic features can be difficult in adult patients. Finally it is evident that skin biopsies can be used in other conditions than lysosomal disorders. The applicability of this procedure to other diseases needs further exploratory work.

Adolescent↗
PubMed1978

Breath hydrogen concentrations after oral lactose and lactulose in tropical malabsorption and adult hypolactasia.

Thirty-six hospital in-patients in London had breath-hydrogen concentrations measured after 50 g lactose were given orally; in 23 or them serial blood glucose concentrations were also estimated. Eight had tropical malabsorption (TM), 14 were Europeans with no detectable disease (normal group) and 14 who also had no detectable disease, were from ethnic groups known to have a very high incidence of genetically determined adult hypolactasia (hl). In 21 of them breath-hydrogen concentrations were also measured after 33.5 g of lactulose were given orally. There was a good inverse correlation between breath-hydrogen production and blood-glucose rise after lactose. Correlations between the first appearance of hydrogen (T) and the area under the hydrogen curve between 0 and 120 min (A) were inversely significant both for lactose and lactulose. Mean T was earlier and mean A greater for lactose compared with lactulose. Correlation between individual values for A after lactase and after lactulose was significant. Indirect measurements of lactase are of no value in either detecting or assessing the severity of TM; that is largely due to the very high incidence of HL in individuals exposed to that disease.

Adult↗
PubMed1991

Time required for gene frequency change in a deterministic model of gene-culture coevolution, with special reference to the lactose absorption problem.

The time required for gene frequency change under natural selection in a deterministic model of gene-culture coevolution is investigated. A discrete generations model is formulated, and its continuous time approximation is derived. In passing to the continuous time limit, it is assumed that the frequency of the culturally transmitted trait does not change under oblique (between generations) transmission. The system of ordinary differential equations thus obtained are solved, and the dependence on the parameters of horizontal (within generations) transmission and natural selection is examined. The time required is found to be substantially longer when the determination of a phenotypic difference subject to natural selection is partly cultural rather than completely genetic. The predictions are relevant to the possibility of the coevolution of lactose absorbers and milk drinkers in some human populations. Alternative hypotheses are briefly discussed in the light of the theoretical results.

Biological Evolution↗
PubMed1991

Automatic end-expiratory air sampling device for breath hydrogen test in infants.

An automatic electronically operated end-expiratory air sampler has been developed for use in small infants. Upon expiration, which is detected by a hot-wire sensor, a small portion of the end-expiratory air is automatically collected into a syringe mounted on a syringe driver. The sampler obtained 87% of the end-expiratory air sample. Additionally, highly reproducible and consistent results were obtained for the respiratory gases (O2, N2, CO2). The sampler has been applied for studying breath hydrogen excretion to detect lactose malabsorption. It may also be applicable to study other expiratory gases in infants.

Breath Tests↗
PubMed1994

Dietary lactose as a possible risk factor for ischaemic heart disease: review of epidemiology.

International data show stronger correlations of mortality from ischaemic heart disease with per capita supply of dairy products excluding fat than with dairy fat, and of estimated lactose than with dairy fat or margarine and other processed fats (positively) and vegetable oils and fats, fat of fish or wine (negatively). Butter and cheese, which have a low content of lactose, show moderate and zero correlations, respectively. Populations with low or intermediate prevalence of adult lactose absorbers have a lower supply of dairy products excluding butter (and therefore of lactose), and a lower mortality from ischaemic heart disease, than populations with a high prevalence of absorbers. Specific national and ethnic data suggest that a diet low or relatively low in lactose, in populations with low or relatively low prevalence of lactose absorbers, is more consistently associated with protection against ischaemic heart disease than are high intakes of unsaturated fatty acids, wine, alcohol or dietary fibre. In seven countries with a high consumption of dairy products (six at least with a high prevalence of lactose absorbers), trends in ischaemic heart disease mortality appear to have reflected changes in the supply of milk (and therefore of lactose), but not consistently of butter or inversely of unsaturated fatty acids. The findings reviewed in this paper call for further investigation of the subject, epidemiologically and biochemically.

Animals↗