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PubMed1997

Occupational sensitization to lactase.

Occupational sensitization to lactase is reported in workers formulating and packaging this consumer product, which is used for the relief of gastrointestinal symptoms caused by intolerance to lactose. Allergic rhinitis, conjunctivitis, and some cases of asthma were noted. There was suggestive evidence that atopic individuals may be at greater risk of sensitization. Lactase should be added to the list of potential occupational respiratory sensitizers.

Asthma↗
PubMed1999

Apolipoprotein A-IV-2 allele: association of its worldwide distribution with adult persistence of lactase and speculation on its function and origin.

Apolipoprotein A-IV (apo A-IV) is a 46-Kd plasma glycoprotein that may play a major role in intestinal lipid absorption. A genetic polymorphism in the apo A-IV gene, apo A-IV-2, encodes a His-->Gln substitution at codon 360 that alters the biological function of this apolipoprotein. As the worldwide distribution of the apo A-IV-2 allele appeared similar to the frequency of a genetic polymorphism that determines the persistence of lactase into adulthood, we examined the relationship between the apo A-IV-2 and lactase persistence polymorphisms by compiling the prevalence of adult lactase persistence in all populations in which the frequency of the apo A-IV-2 allele has been determined. Across 29 groups, there was an extremely strong correlation (4 = 0.937, P < 0.000001) between apo A-IV-2 allele frequency and the prevalence of adult lactase persistence. Apo A-IV-2 allele frequency was highest in Iceland, an ancient Viking colony, and decreased across Europe in a north-to-south and west-to-east gradient, generally following hypothetical isoclines for the lactase persistence gene. There were no correlations between the population frequencies of the apo E2, E3, or E4 alleles and either the prevalence of lactase persistence or the frequency of the apo A-IV-2 allele. In light of the effects of the apo A-IV-2 polymorphism on lipid metabolism, we speculate that the apo A-IV-2 allele may have originated in ancient Scandinavia, spread by conferring a nutritional advantage in the setting of a lifelong high milkfat intake, and was later carried southwards by the Viking incursions into Europe.

Alleles↗
PubMed1977

Morquio-like syndrome with beta galactosidase deficiency and normal hexosamine sulfatase activity: mucopolysacchariodosis IVB.

A 14-year-old white girl with mild dysostosis multiplex, odontoid hypoplasia, short stature, cloudy corneas, keratansulfaturia, but without detectable central nervous system abnormalities was referred with the diagnosis of Morquio syndrome. Clinical and roentgenographic findings were minimal compared to those of typical patients with the Morquio syndrome, MPS IV. Beta-Galactosidase activity in extracts of the patient's cultured fibroblasts was deficient, while that of galactosamine-6-sulfate sulfatase was normal. Conjunctival biopsy revealed intracytoplasmic vacuoles typical of lysosomal storage diseases. It is postulated that in this patient the deficiency of a beta-galactosidase is responsible for inadequate degradation of keratan sulfate and the appearance of a mild form of the Morquio syndrome (MPS IVB).

Adolescent↗
PubMed1980

Beta-galactosidase deficiency: studies of two patients with prolonged survival.

Two adults with beta-galactosidase deficiency were studied. Differences in a number of beta-galactosidase parameters (pH optima, heat denaturation, NaCl kinetics) were noted between the patients. Differences were also noted in beta-galactosidase electrophoretic mobilities and urinary oligosaccharides; however, there was no complementation in cell fusion studies. It is suggested that these two patients have different primary mutations at the beta-galactosidase locus which are probably structural in nature.

Adult↗
PubMed1982

Genetic heterogeneity of I-cell disease is demonstrated by complementation of lysosomal enzyme processing mutants.

I-cell disease (mucolipidosis II) is a fatal childhood disorder affecting the expression of multiple lysosomal acid hydrolases. The disorder is characterized by clinical and biochemical heterogeneity which may reflect different mutants with a similar phenotype. Genetic complementation studies demonstrating genetic heterogeneity within this disorder are described utilizing cultured fibroblasts from 11 different patients. Fibroblasts from I-cell disease (ICD) and from five different lysosomal storage diseases with single structural gene enzyme deficiencies were fused in different combinations, and fractions enriched for multinucleated heterokaryons were isolated and tested for acid hydrolase activity and electrophoretic mobility. In fusions of ICD fibroblasts and various single lysosomal enzyme-deficient fibroblasts, the activity of the deficient enzyme and of the other ICD hydrolases were restored, demonstrating that ICD is not a lysosomal enzyme structural gene defect and that the ICD defect, and not just the single enzyme deficiency, is corrected. In fusions involving only I-cell fibroblasts, at least two complementation groups were identified by the recovery of activities of all lysosomal enzymes tested in heterokaryons. These results demonstrate the existence of genetic heterogeneity within the disorder and suggest that different mutations can result in the I-cell clinical and biochemical phenotype. The data support an altered post-translational processing of lysosomal enzymes as the cause of ICD and suggest that at least two genes participate in this pathway.

Cell Fusion↗
PubMed1983

Morquio B syndrome: a primary defect in beta-galactosidase.

Fibroblasts from patients with Morquio B syndrome contain normal numbers of beta-galactosidase molecules with normal turnover but strongly reduced activity per enzyme molecule. Various substrate affinities are abnormal: the Km for methylum belliferyl (MU)-beta-galactoside is 4-10-fold elevated and affinity for keratan sulphate and oligosaccharides, isolated from Morquio B urine, was not detectable. In contrast, these substrate affinities are normal for beta-galactosidase in adult type GM1-gangliosidosis fibroblasts. Cell hybridization studies demonstrate that Morquio B syndrome and infantile and adult type GM1-gangliosidosis belong to the same complementation group. From these results we conclude that Morquio B syndrome is caused by a mutation in the structural gene for beta-galactosidase, which is allelic to the mutations in infantile and adult type GM1-gangliosidosis. Urinary excretion of keratan sulphate and oligosaccharides is abnormal in Morquio B syndrome but normal in adult type GM1-gangliosidosis. The catalytic properties of beta-galactosidase in Morquio B syndrome and GM1-gangliosidosis provide a possible explanation for the distinct clinical manifestations in these disorders.

Fibroblasts↗
PubMed1981

Chronic GM1 gangliosidosis presenting as dystonia: II. Biochemical studies.

A patient with chronic GM1 gangliosidosis was studied enzymatically and biochemically. Leukocyte acid beta-galactosidase activity was severely deficient. In brain and liver, the 4-methylumbelliferyl beta-galactosidase with acidic pH optimum and lactosylceramidase II were deficient while other hydrolases were present in normal amounts, including sialidase determined with N-acetylneuramin-lactose and fetuin as substrates. Neutral beta-galactosidase in liver was increased up to fourfold over the control. Corresponding to the pathological findings, GM1 ganglioside sialic acid was increased in the basal ganglia to 57% of the total (normal, 12 to 16%), accounting for the rise in total ganglioside to 180% of normal in this origin. Only slight to moderate elevations in the proportion of GM1 ganglioside were noted in the cerebral cortex and white matter, without major increase in total ganglioside. Elevated asialo GM1 ganglioside was also confined to the basal ganglia. There was no increase in hepatic glycoproteins or in keratan sulfate-like materials. This is the only known patient with chronic GM1 gangliosidosis in whom abnormal accumulation of GM1 ganglioside has been demonstrated in affected tissue and sialidase deficiency has been excluded as the primary genetic defect.

Adult↗
PubMed1982

Inborn errors of metabolism.

Inborn errors of metabolism often cause neurological dysfunction. These disorders are most common in childhood, but adult-onset forms with a different clinical presentation are encountered, examples being Pompe disease, Tay-Sachs disease, metachromatic leukodystrophy, Gaucher disease, and Maroteaux-Lamy disease. In the evaluation of a patient with a possible inborn error of metabolism, simple screening tests may aid in the diagnosis and provide direction for more comprehensive laboratory analysis. In most cases, diagnosis can be established without a brain biopsy through biochemical and ultrastructural analysis of peripheral tissues, blood, and urine. New clinical, genetic, and biochemical variants of inherited metabolic disorders are being recognized through wider application of screening tests, improved specificity of laboratory analysis, cell complementation experiments, and the identification of enzyme activator factors. Accurate diagnosis is important for medical management, determining prognosis, and genetic counseling.

Adrenal Insufficiency↗
PubMed1982

Neuraminidase deficiency and accumulation of sialic acid in lymphocytes in adult type sialidosis with partial beta-galactosidase deficiency.

Neuraminidase deficiency has been demonstrated in cultured skin fibroblasts of patients who have adult type sialidosis with partial beta-galactosidase deficiency. A substantial amount of residual enzyme activity has been observed in leukocytes, however. To explain this discrepancy, the nature and distribution of the enzyme were studied. Neuraminidase activity was higher in lymphocytes than in granulocytes of normal controls. In patients' lymphocytes, neuraminidase activity was profoundly decreased and total sialic acid contents were increased 2.3-fold. Two neuraminidases, one sonication-labile and the other sonication-stable, were found in lymphocytes; the former was predominant in cultured skin fibroblasts. The defective enzyme in this disorder was found to be the sonication-labile neuraminidase in both cultured skin fibroblasts and lymphocytes.

Cerebellar Ataxia↗
PubMed1983

beta-Galactosidase-neuraminidase deficiency (galactosialidosis): clinical, pathological, and enzymatic studies in a postmortem case.

Three male siblings in a Japanese family were affected with beta-galactosidase-neuraminidase deficiency (galactosialidosis). One patient died at 45 years of age, and postmortem liver and brain tissues were studied enzymatically. The residual activity of neuraminidase was relatively high in these tissues. Neuraminidase activity did not change in the tissues after repeated freezing and thawing of the homogenates, whereas this enzyme in control tissues lost 30 to 60% of its activity. There was a profound deficiency of beta-galactosidase in the tissues of the patient. Michaelis constant, pH profiles, and cryostability were identical for the patient and control patients. Cathepsin B was moderately increased in activity in the patient's tissues.

Adult↗
PubMed1984

Carrier detection of sialidosis with partial beta-galactosidase deficiency by the assay of lysosomal sialidase in lymphocytes.

Lysosomal and plasma membrane sialidase activities in lymphocytes were studied in four patients with sialidosis with partial beta-galactosidase deficiency, four obligate heterozygotes, and three siblings of a patient. Lysosomal sialidase activity in homozygotes was absent, and that in heterozygotes was significantly decreased to 70% of control level. The results indicate that carriers can be detected by the assay of lysosomal sialidase activity of lymphocytes.

Adult↗
PubMed2006

Milk, milk products and lactose intake and ovarian cancer risk: a meta-analysis of epidemiological studies.

It has been proposed, on the basis of animal models and ecological studies, that consumption or metabolism of dairy sugar may increase the risk of ovarian cancer. Case-control and cohort studies of the association between lactose and dairy food consumption and ovarian cancer risk, however, have yielded varied findings. We summarized the available literature on this topic using a meta-analytic approach. Random-effects models were used to estimate the summary relative risks (RR(summary)). A linear regression analysis of the natural logarithm of the RR was carried out to assess a possible dose-response relationship between lactose intake and ovarian cancer risk. Eighteen case-control and 3 prospective cohort studies were eligible for inclusion in the meta-analysis. The findings of case-control studies were heterogeneous, and, except for whole milk (RR(summary) for highest vs. lowest category = 1.27, 95% confidence interval [CI] = 0.97-1.68), do not provide evidence of positive associations between dairy food and lactose intakes with risk of ovarian cancer. In contrast, the 3 cohort studies are consistent and show significant positive associations between intakes of total dairy foods, low-fat milk, and lactose and risk of ovarian cancer. The RR(summary) for a daily increase of 10 g in lactose intake (the approximate amount in 1 glass of milk) was 1.13 (95% CI = 1.05-1.22) for cohort studies. In conclusion, prospective cohort studies, but not case-control studies, support the hypothesis that high intakes of dairy foods and lactose may increase the risk of ovarian cancer.

Animals↗
PubMed2001

Theoretical and empirical aspects of gene-culture coevolution.

Cultural transmission can be roughly defined as the transfer of information between individuals by social learning (see below). Genes used to be, and for most species still are, the only means available for the accurate transfer of information across generations. In species where cultural transmission has developed, notably the human, interactions can occur between the two inheritance systems. Gene-culture coevolution refers to the evolutionary phenomena that arise from these interactions. As we shall see, these interactions can take various forms.

Adult↗
PubMed1978

Diagnosis of the sphingolipidoses with labelled natural substrates.

The genetic heterogeneity of sphingolipidoses is underlined and the desirability of using natural labelled substrates for the diagnoses of each new index case strongly emphasized. Recent studies of our Scandinavian Krabbe families (more than 50) have repeatedly shown that there is no method developed which can be used for the detection of carriers of the mutant gene in leukocytes or lymphocytes. Also described are enzymic studies in two forms of Gaucher disease which further demonstrate the importance of natural substrates for the diagnoses of the disease in leukocytes and cultivated amniotic fluid cells.

Acetylglucosaminidase↗
PubMed1980

The specificity of beta-galactosidase in the degradation of gangliosides.

Available evidence indicates that a least two genetically distinct acidic lysosomal beta-galactosidases are present in mammalian tissues. One of them, galactosylceramidase, is primarily responsible for degradation of galactosylceramide, galactosylsphingosine, and monogalactosyl-diglyceride, while the other, GM1-ganglioside beta-galactosidase, degrades GM1-ganglioside and asialo GM1-ganglioside. Lactosylceramide can be hydrolyzed by either of the two enzymes. These substrate specificities of the two beta-galactosidases can adequately explain the known findings in the two genetic beta-galactosidase deficiency diseases. The possibilities of the specific lactosylceramidase have not yet received the necessary independent confirmation.

Brain↗