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)

A case study is presented of a 57-year-old male who showed typical clinical features of Cronkhite-Canada syndrome. Numerous polypoid lesions were found in the stomach, duodenum, ileum, colon and rectum accompanied with characteristic ectodermal changes. Tests indicated a protein-losing gastroenteropathy. Intestinal lactase deficiency was demonstrated by the lactose tolerance test. Scanning electronmicroscopy of the gastric and colonic mucosa revealed prominent secretion of mucoid substances and distortion in the gastric pits and colonic crypts. These abnormal findings were interpreted as having a direct relationship to the loss of protein into the gastrointestinal tract.
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PMID:Cronkhite-Canada syndrome. A case report and analytical review of 23 other cases reported in Japan. 52 Jul 67

Acute gastroenteritis is the commonest gastrointestinal disorder in children. It accounted for about 10% of the admissions to a general paediatric unit in Singapore. About 5% of total paediatric admissions to all the government hospitals in Singapore were due to acute gastroenteritis. Some 50% of the cases had no identifiable organism in the stools. Most of the remaining cases were due to bacterial or viral infections. The commonest bacteria responsible for acute gastroenteritis nowadays is Salmonella species. Other bacteria such as E. coli, Shigella and Campylobacter were responsible for a smaller proportion of bacterial diarrhoea in children. Rotavirus was the commonest viral agent responsible for acute diarrhoea among Singapore children. Most patients had mild diarrhoea and severe dehydration following acute gastroenteritis was not common. About 60% of the patients admitted to hospital were younger than two years of age. Bacterial infections were more common in infancy. Viral diarrhoea were more likely to be watery and bacterial diarrhoea were more likely to be bloody and mucoid. With regard to chronicity, it was the groups with mixed infection or bacteria infection which had a prolonged course. Treatment was directed at maintaining hydration and prevention of complications. Except for secondary lactase deficiency, other long term complications were rare.
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PMID:Gastrointestinal infections in Singapore children. 188 88

Lactose-intolerant children manifest diminished or nonexistent intestinal lactase activity, resulting in flatulence, abdominal pain, and diarrhea. To assess the hydrolytic capability of lactase-containing tablets taken immediately before oral lactose challenge, we studied 18 children previously identified as being lactose intolerant and having no underlying organic gastrointestinal disease. Subjects had a mean (+/- SEM) age of 11.4 +/- 3.4 years; 72% were male. At time of the study, lactase-containing tablets or placebo tablets were ingested (double-blind) immediately before drinking a solution of lactose. Breath samples were obtained for hydrogen analysis at 30-minute intervals during a 2-hour period, and clinical symptoms were monitored. In lactose-intolerant patients, hydrogen production was significantly greater following placebo (maximum hydrogen excretion, approximately 60 ppm) compared with lactase-containing tablets (maximum hydrogen excretion, 7 ppm). Increased hydrogen production was associated with clinical symptoms including abdominal pain (89% of subjects following placebo ingestion), bloating (83%), diarrhea (61%), and flatulence (44%). These results indicate, therefore, that coingestion of lactose and lactase-containing tablets significantly reduces both breath hydrogen excretion and clinical symptoms associated with lactose intolerance.
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PMID:Beta-galactosidase tablets in the treatment of lactose intolerance in pediatrics. 212 19

1. In order to develop an improved differential sugar absorption test for simultaneously assessing intestinal permeability and lactose intolerance, methods were established for determining raffinose, lactose and L-arabinose in human urine. Using NAD(P)H-coupled enzymatic assays and fluorimetry, each sugar was measurable over a concentration range of approximately 3-300 mumol/l in diluted urine specimens. 2. After an overnight fast, 40 normal volunteers drank an iso-osmotic solution containing raffinose, lactose and L-arabinose. The median 5 h urinary sugar excretion was 0.26% of the ingested raffinose, 0.05% of lactose and 17.5% of L-arabinose. 3. In 143 patients with gastrointestinal disease, excretion of both ingested raffinose and lactose was significantly increased in coeliac disease in relapse or in partial remission and in Crohn's disease, but not in the irritable bowel syndrome, coeliac disease in remission or ulcerative colitis. Excretion of lactose, but not raffinose, was increased in patients with mucosal lactase deficiency, whereas excretion of L-arabinose was reduced in all disease groups except ulcerative colitis. 4. Discrimination between diseases was poor when based on individual sugar recoveries, but improved dramatically when excretion was expressed relative to that of L-arabinose. The raffinose/L-arabinose excretion ratio, an index of intestinal permeability, was greater than 0.08 in 15/15 untreated coeliac patients but less than 0.06 in all normal subjects and in 9/9 lactase-deficient patients, 15/16 recovered coeliac patients, 5/6 patients with ulcerative colitis, 13/16 patients with Crohn's disease and 61/62 patients with irritable bowel syndrome.
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PMID:Simultaneous assessment of intestinal permeability and lactose tolerance with orally administered raffinose, lactose and L-arabinose. 216 7

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

The frequency of lactose intolerance was studied in patients with chronic gastrointestinal disease, mainly peptic ulcer to explore the possibilities of the use of lactose-poor milk. It was found that whole milk caused dyspeptic symptoms in 45% of patients with peptic ulcer; lactose-intolerance was present in 82% of the patients with milk intolerance; lactose poor powdered milk resulted in complete freedom from symptoms. Use of milk with reduced lactose contents is recommended in the diet of adult patients with lactase deficiency.
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PMID:Lactose-poor milk in adult lactose intolerance. 668 33

Congenital lactase deficiency (CLD) is an autosomal recessive, gastrointestinal disorder characterized by watery diarrhea starting during the first 1-10 d of life, in infants fed lactose-containing milks. Since 1966, 42 patients have been diagnosed in Finland. CLD is the most severe form of lactase deficiency, with an almost total lack of lactase-phlorizin hydrolase (LPH) activity on jejunal biopsy. In adult-type hypolactasia, the most common genetic enzyme deficiency in humans, this enzyme activity is reduced to 5%-10%. Although the activity of intestinal LPH has been found to be greatly reduced in both forms, the molecular pathogenesis of lactase deficiencies is unknown. On the basis of the initial candidate-gene approach, we assigned the CLD locus to an 8-cM interval on chromosome 2q21 in 19 Finnish families. At the closest marker locus, a specific allele 2 was present in 92% of disease alleles. On the basis of a genealogical study, the CLD mutation was found to be enriched in sparsely populated eastern and northern Finland, because of a founder effect. The results of both the genealogical study and the haplotype analysis indicate that one major mutation in a novel gene causes CLD in the Finnish population. Consequently, the critical region could be restricted further, to an approximately 350-kb interval, by ancient-haplotype and linkage-disequilibrium analyses. Surprisingly, the LPH gene was shown to lie outside the critical CLD region, excluding it as a causative gene for CLD. The LPH locus was found to reside >2 Mb from the critical CLD region.
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PMID:Assignment of the locus for congenital lactase deficiency to 2q21, in the vicinity of but separate from the lactase-phlorizin hydrolase gene. 975 22

Congenital lactase deficiency (CLD) is a severe gastrointestinal disorder characterized by watery diarrhea in infants fed with breast milk or other lactose-containing formulas. We initially assigned the CLD locus by linkage and linkage disequilibrium on 2q21 in 19 Finnish families. Here we report the molecular background of CLD via characterization of five distinct mutations in the coding region of the lactase (LCT) gene. Twenty-seven patients out of 32 (84%) were homozygous for a nonsense mutation, c.4170T-->A (Y1390X), designated "Fin(major)." Four rare mutations--two that result in a predicted frameshift and early truncation at S1666fsX1722 and S218fsX224 and two point mutations that result in substitutions Q268H and G1363S of the 1,927-aa polypeptide--confirmed the lactase mutations as causative for CLD. These findings facilitate genetic testing in clinical practice and enable genetic counseling for this severe disease. Further, our data demonstrate that, in contrast to common adult-type hypolactasia (lactose intolerance) caused by a variant of the regulatory element, the severe infancy form represents the outcome of mutations affecting the structure of the protein inactivating the enzyme.
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PMID:Mutations in the translated region of the lactase gene (LCT) underlie congenital lactase deficiency. 1640 Jun 12

Lactase non-persistence (adult-type hypolactasia) is present in more than half of the human population and is caused by the down-regulation of lactase enzyme activity during childhood. Congenital lactase deficiency (CLD) is a rare severe gastrointestinal disorder of new-borns enriched in the Finnish population. Both lactase deficiencies are autosomal recessive traits and characterized by diminished expression of lactase activity in the intestine. Genetic variants underlying both forms have been identified. Here we review the current understanding of the molecular defects of human lactase deficiencies and their phenotype-genotype correlation, the implications on clinical practice, and the understanding of their function and role in human evolution.
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PMID:Molecular genetics of human lactase deficiencies. 1963 77

Necrotizing enterocolitis (NEC) remains the most severe gastrointestinal disorder in preterm infants. It is associated with the initiation of enteral nutrition and may be related to immature carbohydrate digestive capacity. We tested the hypothesis that a formula containing maltodextrin vs. a formula containing lactose as the principal source of carbohydrate would predispose preterm pigs to a higher NEC incidence. Cesarean-derived preterm pigs were given total parenteral nutrition for 48 h followed by total enteral nutrition with a lactose-based (n = 11) or maltodextrin-based (n = 11) formula for 36 h. A higher incidence (91% vs. 27%) and severity (score of 3.3 vs. 1.8) of NEC were observed in the maltodextrin than in the lactose group. This higher incidence of NEC in the maltodextrin group was associated with significantly lower activities of lactase, maltase, and aminopeptidase; reduced villus height; transiently reduced in vivo aldohexose uptake; and reduced ex vivo aldohexose uptake capacity in the middle region of the small intestine. Bacterial diversity was low for both diets, but alterations in bacterial composition and luminal concentrations of short-chain fatty acids were observed in the maltodextrin group. In a second study, we quantified net portal absorption of aldohexoses (glucose and galactose) during acute jejunal infusion of a maltodextrin- or a lactose-based formula (n = 8) into preterm pigs. We found lower net portal aldohexose absorption (4% vs. 42%) and greater intestinal recovery of undigested carbohydrate (68% vs. 27%) in pigs acutely perfused with the maltodextrin-based formula than those perfused with the lactose-based formula. The higher digestibility of the lactose than the maltodextrin in the formulas can be attributed to a 5- to 20-fold higher hydrolytic activity of tissue-specific lactase than maltases. We conclude that carbohydrate maldigestion is sufficient to increase the incidence and severity of NEC in preterm pigs.
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PMID:Carbohydrate maldigestion induces necrotizing enterocolitis in preterm pigs. 1980 55


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