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)

Parietal measurements of pH values in patients with various intestinal diseases and in normal subjects have revealed that alkaline medium with gradual elevation of the values in the caudal direction is characteristics of the normal large intestine; acid pH values were registered in patients with lactase insufficiency, nonspecific ulcerative colitis, in contrast to those with post-dysentery colitis and tumors of the large intestine. Lactulose and sodium sulfate were found the factors that significantly influence the large intestine parietal pH values, the effects of wheat bran were lower; magnesium sulfate and sodium hydrocarbonate mineral water with medium mineral content had no effect on parietal pH values.
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PMID:[The use of parietal pH-metry in the diagnosis of intestinal diseases]. 170 48

Several alterations of the small-intestinal morphology and function have been documented after alcohol ingestion. There are morphologic changes macroscopically and microscopically after acute alcohol administration in the proximal part of the small intestine, which are quickly reversible. There are no macroscopic changes and, in most patients, very discrete light microscopic changes in the small intestine after chronic alcohol ingestion. The ultrastructural changes are, however, profound, as seen by both transmission and scanning electron microscopy. The permeability is probably increased, permitting entrance of possible noxious agents, which may explain some of the extraintestinal tissue damage observed in chronic alcoholism. The transit is increased, at least after acute alcohol administration, perhaps contributing to the diarrhea commonly seen after heavy drinking. Several of the enzymes located in the brush border are affected; lactase activity can be depressed and perhaps result in a transient milk intolerance in predisposed individuals. The activity of GGT is increased and may partly account for the GGT elevation in serum after heavy drinking. Other enzymes, such as Na(+)-K(+)-ATPase, can be inhibited and result in a decreased absorption of substances that require active, energy-dependent transport mechanisms. The secretion of water and electrolytes may be increased (an effect on cAMP?). The absorption of several nutrients, vitamins, and other elements is disturbed. The bacterial flora is increased and changed, which may give rise to symptoms and also increase the production of acetaldehyde by bacterial metabolism of ethanol. Acetaldehyde is more toxic than ethanol, and an increased concentration of acetaldehyde can possibly accentuate the damage to the liver and other organs. The bacterial overgrowth can possibly cause endotoxinemia. Although studies on alcohol-related intestinal alterations have been relatively sparse, the acute and chronic effects of alcohol thus seem to be considerable. From available results it is, however, difficult to draw any definite conclusions about the clinical importance of many of the findings. Future research will need to study the relationship between, for example, the chronic morphologic changes, the absorptive dysfunction, and permeability alterations, on the one hand, and the gastrointestinal symptoms, the extraintestinal damage, and various deficiencies, on the other hand.
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PMID:Alcohol and the small intestine. 200 95

Adult mammals generally demonstrate a lower preference for the disaccharide sugar lactose than for any other common sugar, and because adults typically have low levels of the intestinal enzyme lactase, lactose ingestion may cause gastrointestinal distress. The lactose intake of adult golden hamsters was examined in three experiments; the main findings were: (a) hamsters allowed to choose between tap water and lactose solutions (maximum concentration = 32% weight/volume) over a 20-day period showed a clear preference for lactose solutions and ingested substantial quantities of lactose (up to 3 g/100 g body weight/day) without noticeable adverse effects; (b) hamsters consuming a single diet with lactose added (maximum concentration = 50%) over a period of days ingested up to 3.42 g/100 g body weight/day of lactose without noticeable adverse effects; (c) both hamsters with prior exposure to lactose solutions and those without such exposure consumed similar amounts of 32% lactose solution over an 8-day period, suggesting that hamsters' lactose intake does not depend on the occurrence of adaptation. It is suggested that the fermentative capacity of the hamster's pregastric pouch may underlie this animal's unusual tolerance for lactose.
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PMID:Lactose ingestion in the adult golden hamster (Mesocricetus auratus). 203 61

The effect of ingested epidermal growth factor (EGF) on the small intestinal mucosa of conventionally weaned pigs was determined. At 21 days of age, 39 pigs were randomly distributed into suckling and weaned treatment groups that were administered 124 micrograms of EGF, 372 micrograms of EGF, or the dosing compound daily. Fecal water content was determined daily. On postweaning days 0, 3, 6, and 9, representative pigs from each group were euthanatized, and jejunal mucosa samples were collected for determination of villus-to-crypt ratio, total protein content, disaccharidase activities, and microbiological populations. At postweaning day 3, the 372-micrograms dose of EGF significantly (P less than or equal to 0.05) increased jejunal lactase and sucrase activities in the weaned pigs. Increased lactase activity was not greater than that of the suckling pig controls, whereas sucrase activity was significantly (P less than or equal to 0.05) higher than that of the suckling pig controls. Significant changes were not observed in villus-to-crypt ratio, mucosal protein content, or disaccharidase activities on other collection days.
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PMID:Effect of orally administered epidermal growth factor on the jejunal mucosa of weaned pigs. 210 78

The effect of supplementation of the diet with galactose on the age-related decline of intestinal lactase activity was investigated in 108 growing rats. Starting from 14 days of age, the rats were divided into two groups and fed with chow, and with fluid either as tap water or 5% galactose solution. At 14 days the specific lactase activity was 112.8 +/- 3.2 mumol min-1 (g protein)-1, which decreased to less than 10% of this value at maturity. Galactose supplementation did not prevent the decline. The increase of maltase, sucrase and trehalase was also unaffected. The result suggests that galactose plays no significant role in the regulation of disaccharidase activities in the rat.
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PMID:The effect on intestinal disaccharidase activity of feeding galactose to growing rats. 224 21

Because adult rats have very low levels of the intestinal enzyme lactase, the ingestion of appreciable quantities of the disaccharide lactose may cause gastrointestinal distress. The present experiment was designed to demonstrate that adult rats will learn to avoid previously neutral stimuli which have been paired with lactose ingestion. Adult rats ingested both a novel solution [either tap water (WA) or 0.1% saccharin (SA)] and a novel food substance (49% powdered lab chow + 50% added disaccharide + 1% saccharin) during a single conditioning session. The added disaccharide was either sucrose (group SU-SA), lactose (groups HL-SA and HL-WA), or equal amounts of these two disaccharides (group LL-SA); a fifth group (LC-SA) consumed a sucrose-containing diet to which lithium chloride was added (5 mg per 1 g of diet). Separate feeding tests and drinking tests, carried out over several weeks, were used to assess the extent of conditioned taste avoidance. In the four feeding tests, rats were allowed to ingest powdered lab chow with added saccharin (but without added disaccharide), while in the four drinking tests, rats chose between tap water and a 0.1% saccharin solution. Group HL-SA demonstrated a substantial conditioned avoidance in both feeding and drinking tests, but group HL-WA showed avoidance only in feeding tests. Conditioned avoidance was weak in group LL-SA; the strongest avoidance was observed in lithium chloride-treated rats (group LC-SA). Results are related to previous research and to the hypothesis that a learned avoidance of milk may facilitate the weaning process in mammals.
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PMID:Conditioned taste avoidance induced by lactose ingestion in adult rats. 233 39

We report the primary structures of human and rabbit brush border membrane beta-glycosidase complexes (pre-pro-lactase-phlorizin hydrolase, or pre-pro-LPH, EC 3.2.1.23-62), as deduced from cDNA sequences. The human and rabbit primary translation products contain 1927 and 1926 amino acids respectively. Based on the data, as well as on peptide sequences and further biochemical data, we conclude that the proteins comprise five domains: (i) a cleaved signal sequence of 19 amino acids; (ii) a large 'pro' portion of 847 amino acids (rabbit), none of which appears in mature, membrane-bound LPH; (iii) the mature LPH, which contains both the lactase and phlorizin hydrolase activities in a single polypeptide chain; (iv) a membrane-spanning hydrophobic segment near the carboxy terminus, which serves as membrane anchor; and (v) a short hydrophilic segment at the carboxy terminus, which must be cytosolic (i.e. the protein has an Nout-Cin orientation). The genes have a 4-fold internal homology, suggesting that they evolved by two cycles of partial gene duplication. This repetition also implies that parts of the 'pro' portion are very similar to parts of mature LPH, and hence that the 'pro' portion may be a water-soluble beta-glycosidase with another cellular location than LPH. Our results have implications for the decline of LPH after weaning and for human adult-type alactasia, and for the evolutionary history of LPH.
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PMID:Complete primary structure of human and rabbit lactase-phlorizin hydrolase: implications for biosynthesis, membrane anchoring and evolution of the enzyme. 246 Mar 43

Physicians studied 16 moderately to severely malnourished infants 6 months old who had severe diarrhea for 2 weeks and did not gain weight. After admitting the infants, they administered total parenteral nutrition (TPN) to the infants through a central vein. As the infants began receiving TPN, they were randomly assigned to receive either banked human milk or sterile water by continuous nasogastric feeding for 2 weeks. In addition, before beginning nasogastric feedings and at the conclusion of the study, a physician performed a peroral biopsy of the small intestine. Small intestine perfusion studies were also done in the beginning and at the end of the 2 week period. More infants in the human milk group than in the sterile water group had 25% decrease in sucrase activity (p.02). Researchers noted that the villus/crypt ratio was similar in both groups at the beginning of the study and improved only in the sterile water group (p.002), but this was not a function of treatment. Additionally, more infants in the human milk group had an increase in the intraepithelial lymphocyte count than those in the sterile water group (milk, 5/7; water, 1/8; p.03). On the other hand, the data demonstrate that no differences existed in glucose and water absorption or in lactase and maltase activities as a function of the milk versus water treatment. Therefore, the results of this study suggest that human milk does not benefit small intestine mucosa recovery. Research to determine the effect of predigested formulas or specific factors in fresh human milk on the rate of mucosal recovery is needed.
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PMID:Human milk and the rate of small intestinal mucosal recovery in protracted diarrhea. 249 97

Intestinal calcium absorption from milk containing lactose (+) and from another containing glucose (-) was studied in eight patients with normal lactase (NL) and seven lactase-deficient (LD) subjects to determine if lactase deficiency is implicated in Ca absorption. The results were compared with data obtained from Ca ingestion in a water solution. Ca absorption was measured by a double-isotope technique and the kinetic indices were obtained by a deconvolution method. With (-), Ca absorption was identical in NL and LD subjects and slightly higher than with water solution (15%, NS). With (+), Ca absorption in NL subjects was identical with that from water solution; in LD subjects it increased (23%, p less than 0.02). These data indicate that: Ca is absorbed equally well from milk as from water solution; (+) favors Ca absorption in LD subjects, which suggests that milk ingestion might be encouraged in LD subjects to avoid Ca deficiency; and (-) should be a valuable alternative for lactose-intolerant patients.
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PMID:Calcium absorption from milk in lactase-deficient subjects. 249 46

The effect of chronic intragastric infusion of hypertonic mannitol on small intestinal mucosal structure and function was studied in adult rats. Animals were gavage-fed 20% mannitol (1300 mosm) at a dose of 5 ml/100 g body weight daily for seven days. Control animals were gavage-fed tap water on the same schedule. On day 8, the animals were anesthetized, the duodenum cannulated, and a test sugar (glucose, glucose polymer, lactose, sucrose, or maltose) was infused at a dose of 0.5 g/kg body weight in 2.5 ml distilled water over less than 1 min. Portal vein glucose was measured at 30-min intervals from 0 to 120 min. Mannitol treatment resulted in histologic and biochemical alterations (reduced lactase, sucrase, maltase) limited to the proximal small intestine compared to the control group. The absorption of glucose and glucose polymers was similar in mannitol-treated and control animals. In contrast, digestion and absorption of lactose, sucrose, and maltose was significantly diminished in mannitol-treated animals when compared to controls. No changes in permeability to polyethylene glycol 4000 or Na+-coupled glucose transport were observed in mannitol-treated animals compared to controls. These data suggest that when the intestinal mucosa is exposed to hyperosmolar loads that the digestive capacity for disaccharides is suppressed more than its glucose absorptive capacities. Furthermore, glucose oligomers may be more readily digested and absorbed than disaccharides, in this setting, due, in part, to the proximal injury and less pronounced proximal-distal gradient for glucoamylase than other brush-border carbohydrases.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Proximal small intestinal mucosal injury. Maintenance of glucose and glucose polymer absorption, attenuation of disaccharide absorption. 249 65


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