Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.108 (lactase)
 2,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The incidence of lactase deficiency, evaluated by means of a lactose absorption test with blood glucose measurements, was compared in a group of 58 women suffering from postmenopausal osteoporosis and a control group of 51 normal women of the same age and ethnic origin. In the patients suffering from osteoporosis, the examination was completed by a glucose-galactose absorption test and in the control group by a hydrogen breath test. The prevalence of lactase deficiency is of approximately the same magnitude in the two groups (25.8% and 33.3% respectively). Dietary investigations showed a calcium intake superior to 1 g per day in only 40% of the osteoporotic patients, this deficiency being more important in cases where lactase deficiency was observed than in those showing normal lactose absorption. The influence of lactose malabsorption on the calcium balance, and the role of the latter in the pathogenesis of osteoporosis, are discussed.
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PMID:[Incidence of lactase deficiency in patients with involution osteoporosis and in normal subjects. Its effect on the nutritional intake of calcium and phosphorus]. 368 31

To determine whether lactose influences the absorption of calcium, the uptake of calcium from lactose-hydrolyzed milk and from unhydrolyzed milk was measured in 20 adults: 10 were lactase-deficient and 10 were lactase-sufficient as defined by breath hydrogen test, plasma glucose determination after oral lactose dose, and presence or absence of symptoms after lactose ingestion. On different days, each subject received either lactose-hydrolyzed or unhydrolyzed milk. Calcium absorption was measured by a double-isotope technique. In the lactase-deficient group, the mean absorptions were 33.5% from hydrolyzed milk and 36.2% from the same volume of unhydrolyzed milk (P greater than 0.30). In the lactase-sufficient group, mean absorptions were 24.2% from hydrolyzed milk and 25.7% from unhydrolyzed milk. The mean calcium absorption from both lactose-hydrolyzed milk and unhydrolyzed milk was significantly greater (P less than 0.01) in the lactase-deficient group compared to the lactase-sufficient group, presumably reflecting lower dietary calcium intake in the former. These data indicate that, in lactase-deficient subjects, malabsorption of lactose does not affect calcium absorption.
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PMID:Calcium absorption from milk in lactase-deficient and lactase-sufficient adults. 375 2

The prevalence of lactase deficiency is high in Mediterranean, Middle Eastern and Asian countries, which suggests that many immigrants and immigrant children from these regions may be unable to produce lactase. Therefore, the aim of this study was to determine the prevalence of lactose malabsorption in primary school-aged children, in two communities with a high proportion of immigrants in metropolitan Sydney. A total of 109 children, aged five to 12 years, were studied by means of the breath hydrogen method. Forty per cent (44/109) showed lactose malabsorption, as defined by a rise in end-expiratory hydrogen levels of 20 ppm or more, two hours after loading with lactose. The prevalence was highest in the subjects of Asian origin (93%; 14/15), followed by Greek subjects (56%; 14/25) and subjects from other Mediterranean and Middle Eastern countries (41%; 15/37). Of the 77 children who were available for follow-up, 57% (44) reported symptoms of lactose intolerance, of whom nearly two-thirds were children who showed lactose malabsorption. The high prevalence of lactase deficiency in children at both schools underlines the need to consider the multiracial identity of Australians in planning educational programmes about nutrition.
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PMID:Lactase deficiency in Australian school children. 376 58

The clinical and nutritional significance of radiation enteritis was assessed in eight patients with chronic diarrhea which followed curative doses of radiotherapy for pelvic malignancies. Steatorrhea, found in seven malnourished patients, was ascribed to ileal disease or previous surgery, or to bacterial contamination of the small intestine. Lactose intolerance, assessed by breath hydrogen excretion after oral lactose and by jejunal lactase levels, was found in six patients. In a subgroup of five patients, the administration of two different defined formula liquid diets by nasoduodenal infusion decreased fecal fluid and energy losses by about one-half. Compared to Vivonex-HN, the infusion of Criticare-HN was associated with greater likelihood of intestinal gas production but a three-fold greater utilization of protein. Intestinal malabsorption and malnutrition in radiation enteritis has diverse etiologies. Whereas nutritional support by liquid diet limits fecal fluid and energy losses, these diets differ significantly in clinical tolerance and biologic value.
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PMID:Clinical and nutritional implications of radiation enteritis. 391 1

The feasibility and efficacy of adding microbial beta-galactosidase enzymes directly to milk at the time of consumption was explored in adult lactose-malabsorbers. The hydrogen breath test, and on one occasion, the rise in blood glucose, were used as indices of the completeness of intraintestinal hydrolysis and absorption of milk lactose. When added to 360 ml of cow milk containing 18 g of lactose, empirical dosages of three beta-galactosidases--one from Kluyveromyces (yeast) and two from Aspergillus (fungal)--had some effectiveness in reducing postprandial H2 excretion, although no in vivo treatment at the dosages chosen was as effective as pre-incubation of the milk in vitro. The yeast enzyme also reduced symptom frequency as compared to intact milk and enhanced postprandial rises in blood glucose. The replacement therapy with exogenous, food-grade beta-galactosidases may provide a useful intervention to reduce lactose malabsorption and milk intolerance in individuals with primary lactase deficiency.
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PMID:Dietary manipulation of postprandial colonic lactose fermentation: II. Addition of exogenous, microbial beta-galactosidases at mealtime. 391 30

The feasibility of enzyme replacement therapy with exogenous, food-grade, microbial enzymes at mealtime to effect intragastrointestinal hydrolysis of the lactose from 360 ml of cow's milk consumed with a solid food meal (breakfast cereals) was investigated in adult Guatemalan lactose-malabsorbers using a hydrogen breath-analysis procedure to quantify the completeness of postprandial carbohydrate absorption. Adding 2 g of a commercial preparation of beta-galactosidase from Kluyveromyces lactis at mealtime to milk taken with a refined cereal (cornflakes) and an unrefined cereal (bran) reduced the production of excess breath H2 attributable to lactose maldigestion to a level not significantly different from that achieved with lactose-prehydrolyzed milk. Sucrase, as expected, had no effect on H2 production. A beta-galactosidase from Aspergillus niger was less effective that the K. lactis enzyme for in vivo hydrolysis. Thus, exogenous betagalactosidases can eliminate lactose malabsorption in lactase-deficient individuals even in the presence of solid foods, allowing lactose intolerant persons to consume milk and dairy products without gastrointestinal discomfort.
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PMID:Effective in vivo hydrolysis of milk lactose by beta-galactosidases in the presence of solid foods. 391 31

The definition of "insufficient" small bowel lactase activity varies greatly among authors. The present study is aimed at redefining lactase insufficiency by comparing intestinal lactase activity and results of the lactose breath hydrogen test. Primary "insufficient" lactase activity was considered to be present when a child with a normal small bowel histology showed lactose malabsorption as measured by the lactose breath hydrogen test. The lactase activity of 22 "normal" children ranged from 0.77 to 4.57 U/g wet weight, while five children showed primary lactase insufficiency as defined above. Small bowel lactase activity in the latter patients was less than 0.74 U/g wet weight. Sucrase and maltase activities were similar in both groups of patients. We conclude that children with a normal small bowel histology should be considered to have primary lactase insufficiency when small bowel lactase activity is below 0.75 U/g wet weight.
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PMID:Lactase insufficiency revisited. 393 58

Lactose malabsorption is not a cause of diarrhea during phototherapy. Jaundiced neonates under phototherapy develop diarrhea or loose stools during the treatment. These phenomena were attributed to an induced lactase deficiency caused by bilirubin breakdown products. We investigated lactose malabsorption in 59 neonates--29 normals and 30 jaundiced under phototherapy. Five-hour hydrogen breath tests were performed. Preprandial and postprandial (at 30, 60, 120, 180, 240, and 300 min) expired air samples were analyzed for hydrogen. Ten controls and five jaundiced neonates had positive hydrogen breath tests. Eighteen controls and 16 neonates under phototherapy had preprandial hydrogen (concentrations above 5 ppm). In our hands, lactase deficiency and lactose malabsorption were not induced by phototherapy. Lactase deficiency is therefore not the cause of diarrhea associated with phototherapy.
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PMID:Lactose malabsorption is not a cause of diarrhea during phototherapy. 398 20

22% of a group of adult Neapolitans were found to have persistent high lactase activity, and 16% were lactose absorbers as indicated by measurement of breath hydrogen concentration and rise in blood glucose after oral lactose administration. Among adults in the same area with idiopathic senile or presenile cataract 49% were identified as lactose absorbers with the breath hydrogen test and 55% by the rise in blood glucose. These results suggest that adults able to absorb galactose from a lactose-containing diet are especially susceptible to senile or presenile cataract.
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PMID:High frequency of lactose absorbers among adults with idiopathic senile and presenile cataract in a population with a high prevalence of primary adult lactose malabsorption. 614 22

Invasive tests to diagnose patients with gastrointestinal disease are rapidly being replaced by procedures which enable organ function to be assessed by monitoring the product of a metabolic reaction in readily available materials such as breath, blood, and urine. Examples of these approaches that will be assessed in this review include the hydrogen breath test for lactase deficiency, radioactive carbon dioxide breath measurements to test for fat digestion and absorption, and tests of pancreatic function based upon synthetic substrates from which fluorescein or para-aminobenzoic acid can be liberated by pancreas-specific enzymes. Significant advances have been made in improving the organ sensitivity of enzyme determinations. The determination of amylase isoenzymes has been less useful than the measurement of immunoreactive trypsin; this latter enzyme is greatly elevated in the blood of neonates with cystic fibrosis, whereas serum levels are greatly depressed in cystic fibrosis patients with pancreatic insufficiency as well as in most patients with steatorrhea due to chronic pancreatitis. Many of these tests are now becoming standard procedures in the investigation of infants with gastrointestinal disease.
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PMID:The noninvasive biochemical diagnosis of gastrointestinal disease, with special reference to children. 621 Jan 70


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