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

The pathogenesis of diarrhea caused by rotavirus infection was studied in miniature swine piglets. The animals were inoculated orally with 2 X 10(7) plaque-forming units of porcine rotavirus (OSU strain). During the height of diarrhea, intestinal function was investigated by in vivo perfusion of a 30-cm segment of proximal jejunum and a 30-cm segment of distal ileum. Absorption of Na+ and water decreased and 3-O-methylglucose transport was markedly reduced, P less than 0.01 compared to control animals. Mucosal lactase and sucrase levels were depressed in both the jejunum and ileum, P less than 0.001. Na+,K+-ATPase activity was significantly depressed only in the ileum, P less than 0.001. These changes were associated with a marked reduction in villous height, suggesting that the diarrhea could be an osmotic diarrhea due to nutrient (carbohydrate) malabsorption. Fresh stool samples were obtained and analyzed immediately for NA+,K+, osmolarity, glucose, and lactose; the osmotic gap was also determined. Stool osmolarity continually increased from 248 +/- 20 mosm/liter prior to inoculation to 348 +/- 20 mosm/liter at 75 +/- 1 hr postinoculation (P less than 0.005); the majority of the fecal osmotic gap could be accounted for by the amount of lactose present in the stools. Stool sodium increased from 34 +/- 6 mM prior to inoculation to a maximum of 65 +/- 4 mM at 53 +/- 1 hr postinoculation, P less than 0.001. There was no significant change in potassium concentration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pathogenesis of rotavirus-induced diarrhea. Preliminary studies in miniature swine piglet. 648 82

In vivo jejunal transport of amino acids, monosaccharides, sodium, and electrolytes were studied in rats made nephrotic with puromycin aminonucleoside (PAN) and in pair-fed controls. Studies were performed 14 days after a single intravenous dose of PAN when rats were no longer edematous, but were still hypoproteinemic. There was decreased absorption of glucose, 3-0-methyl glucose, glycine, phenylalanine, histidine, water, and sodium in the nephrotic animals but transport of fructose, lysine and potassium was similar in the nephrotic and control animals. Enzyme kinetic studies for glucose transport showed a mixed type of inhibition affecting both Vm and Km. The jejunal mucosa of nephrotic and control rats had similar ATP content and enzyme activity for lactase, sucrase, maltase and (Na-K)-ATPase and the ratios of RNA to DNA were similar in the nephrotic and control rats. No abnormality of the jejunum was detected by light or electron microscopy. The data suggest that the impairment of absorption is a result of decreased activity of jejunal membrane carrier mechanisms. The altered transport may be secondary to effects related to the metabolic consequences of nephrotic syndrome and does not appear to be related to acute purine aminonucleoside toxicity, edema or malnutrition.
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PMID:Jejunal transport in experimental nephrotic syndrome. 662 9

The author suggests that under certain conditions cultured milk, rather than fluid milk, can be used for infant and child nutrition as well as for school milk programs. Some of the major problems with fluid milk, fresh or reconstituted, are discussed. A review of the literature indicates that the assumption of lactose intolerance among many populations is exaggerated. Inappropriate handling of pasteurized milk very often is responsible for a high bacterial count and organoleptic defects. Such quality defects are more pronounced in countries with a warm climate. The use of polluted water in the reconstitution of milk powder, is probably more often responsible for diarrhea than lactose intolerance. For these reasons it is suggested that under appropriate conditions a cultured milk product such as yogurt or quark, be used for infant and child nutrition. The advantages are: 1) the low pH caused by the high lactic acid content detrimentally affects food spoilage and pathogenic organisms in milk; 2) longer shelf life of the fermented product at ambient temperature; and 3) fermented milk products contain the enzyme lactase which facilitates digestion of residual lactose even after ingestion.
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PMID:The potential value of cultured dairy products for child nutrition. 668 16

The effects of bilateral adrenalectomy and subsequent force-feeding of L-tryptophan (30 mg/100 g body weight) on the activity of disaccharidases (lactase, sucrase, and maltase) in the jejunum and ileum were investigated. One month after adrenalectomy the activity of lactase, sucrase, and maltase in the ileum and of lactase and maltase in the jejunum was significantly decreased when compared with that of the sham-operated controls. In adrenalectomized rats, administration of tryptophan (24 h later) produced significant increments in lactase and maltase activities in both jejunum and ileum, compared with the corresponding water-fed adrenalectomized control.
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PMID:Effect of adrenalectomy and tryptophan force-feeding on the activity of intestinal disaccharidases in adult rats. 677 Apr 55

Discovery of small numbers of people with the gene for persistence of intestinal lactase into adult life (PL) in several parts of Papua New Guinea (PNG) suggests that sporadic mutation as well as diffusion could account for at least part of its present distribution. The existing hypotheses attempting to account for at least part of its present distribution. The existing hypotheses attempting to account for the distribution of the gene have been applied to the available evidence in PNG populations. The water absorption and linkage disequilibrium hypotheses are possible explanations for selection of the trait; the culture historical and calcium absorption hypotheses seem unlikely, however, to explain the observed frequencies. It seems possible that more intensive study of the properties of the enzyme might reveal a connection with processes other than lactose hydrolysis.
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PMID:The intestinal lactase polymorphism in Papua New Guinea. 678 Nov 63

We compared the absorption of carbohydrate from solutions of glucose oligomers and glucose in jejunal Thiry-Vella fistulae, a preparation deprived of pancreatic secretions. The studies were performed with two concentrations (90 and 360 mg/dl) of both glucose and the glucose oligomers. Carbohydrate absorption from glucose solutions (33.1 +/- 2.8, 115.9 +/- 8.9 micrograms/cm/min) was significantly greater (P less than 0.025; P less than 0.005) than that from oligomer solutions (26.6 +/- 2.1 and 92.4 +/- 9.0 micrograms/cm/min). Thin-layer analyses of the perfusates demonstrate digestion of oligomers with a chain length up to eleven and suggest digestion of oligomers of even greater chain length. Atrophy of the jejunal mucosa occurred over the course of the study as evidenced by a decrease in the ratio of villous height to crypt depth from 3.8 to 0.3, and by a 80% decrease in the activity of maltase, sucrase, and lactase. Atrophy was accompanied by a significant decline in the absorption of both glucose oligomers (P less than 0.005) and glucose (P less than 0.01) from the more concentrated solutions but the decrement in absorption of both carbohydrates was similar: glucose oligomers, 79.3 +/- 19.4 micrograms/cm/min; and glucose, 69.8 +/- 14 micrograms/cm/min (P greater than 0.20). Water absorption was enhanced by both carbohydrates, but there was no demonstrable difference between solutions of glucose and glucose oligomers. The osmolality of the solutions clearly influenced water absorption (P less than 0.025) but failed to effect the absorption of carbohydrates.
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PMID:The jejunal absorption of glucose oligomers in the absence of pancreatic enzymes. 722 Jan 47

The capacity of intestinal lactase (EC 3.2.1.23) of piglets to hydrolyse lactose in vivo was investigated by measuring the response of blood galactose to doses of lactose, galactose plus glucose and both whole and skimmed milk. Following the administration of oral doses of lactose dissolved in water to piglets from 2 to 18 d of age the adjusted galactose area under the curve (AUC) was between 1.12 and 1.36 arbitrary units, while following a dose of galactose plus glucose dissolved in water it was between 1.56 and 1.98 arbitrary units. Whereas these results suggest that the rate of digestion of lactose appeared to limit the amount of galactose reaching the peripheral blood after a dose of lactose dissolved in water, there was no significant correlation between the capacity of piglets to hydrolyse physiological amounts of lactose and the age of the piglets (2- to 18-d-old piglets; r 0.11). Following oral doses of sow's milk containing either lactose, or galactose plus glucose, the adjusted galactose AUC values were 0.94 and 1.00 arbitrary units respectively, in 10-d-old piglets. Thus, the limitation to the digestion of lactose observed when it was present in water was not evident for lactose in sow's milk. Since there was no significant difference between the adjusted galactose AUC following a dose of whole milk (0.95 arbitrary units) and that following a dose of skimmed milk (1.03 arbitrary units), the presence of fat in sow's milk did not appear to affect the utilization of lactose by the sucking piglets.
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PMID:The responses of blood galactose to oral doses of lactose, galactose plus glucose and milk to piglets. 762 93

Diarrhea is one of the most common causes of morbidity and mortality in infants and children less than 5 years old in developing countries. Diarrheal diseases are a major cause of childhood malnutrition. Toxin-producing bacteria are responsible for many acute diarrheas. Oral rehydration solution (ORS) treats dehydration caused by acute diarrheal episodes. WHO promotes the use of a single oral rehydration formula which contains 3.5 g sodium chloride, 2.5 g sodium bicarbonate or 2.9 g trisodium citrate dihydrate, 1.5 g potassium chloride, and 20 g glucose to 1 liter of water. This ORS formula can safely be used for all age groups and all etiologies of diarrhea. ORS replaces the lost fluid and electrolytes and maintains fluid and electrolytes. Pediatricians in most developed countries do not accept this ORS formula in cases of rotavirus-caused diarrhea because rotavirus blunts some absorptive villi and reduces the activity of lactase and other disaccharidase, resulting in reduced absorption. Yet, the unaffected villus cells may absorb enough water and electrolytes to be effective. In cases of vomiting, ORS should be administered in small amounts and slowly. Some health workers are concerned that 90 mmol/l sodium in the WHO formula causes hypernatremia in neonates and young infants who have low sodium levels in their stools. Specialists suggest ORS with 30-60 mmol/l or additional water administered in a 2:1 ratio for these young infants. Hypernatremia is also a concern for malnourished children, but studies show that WHO's ORS is safe and effective in treating malnourished children. Bottle fed children are more vulnerable to hypernatremia than breast fed children. Hypernatremia has neurological effects. Hyponatremia is more common in developing countries than developed countries. It also has neurological effects. In severe dehydration cases, intravenous fluid or ORS delivered via a nasogastric tube should be given immediately.
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PMID:Usefulness of ORT in certain special situations of diarrhoeal diseases. 783 95

Important variations in intestinal biochemical characteristics were recorded after ingestion of a single dose of spermine (8 mumol 50 microliters-1 water) by rats which were 11 days old. Two phases of events were observed. During the first hours which follow spermine administration, we mainly noted: -a decrease in the weight of DNA and of intestine per cm, -a decrease in the specific activity of lactase and of maltase, -an increase in the spermine content. The second phase of events started about 30 h after spermine ingestion. We observed: 1. An increase in the weight of DNA and of intestine per cm; 2. The appearance of sucrase activity; 3. An increase in maltase specific activity; 4. An increase in spermidine content; 5. tendency to normalization of the spermine content. The epithelial cells of the proximal intestine were isolated in fractions from the top of the villi to the bottom of the crypts. Two hours after spermine administration, we noted: 1. An increase in the lactase specific activity of the epithelial cells located at the top of the vili; 2. A decrease in the activity of the cells situated at the lower part of the crypts; 3. An increase in the specific activity of maltase contained in the different categories of enterocytes, except in those from the bottom of the crypts; 4. An increase in the content of putrescine present in the epithelial cells of the whole axis excepted in the bottom of the crypts; 5. An increase in the spermidine and spermine content of all the cell fractions.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evolution of biochemical parameters characterizing the proximal small intestine after orally administered spermine in unweaned rats. 806 97

To assess the effects of hypothyroidism (HT) on small-intestinal function, HT was induced in rats (120-150 g) by methimazole in drinking water. After 6 wk of methimazole, intestinal absorption studies were performed in HT and in control (C) rats by in situ luminal perfusion of a 20-cm proximal jejunal loop with a bicarbonate buffer containing sodium, glucose or fructose, glycine or lysine, and phenol red as a nonabsorbable marker for determination of water fluxes. Mucosa from the perfused segment was taken for assay of disaccharidases and ATPases and for light and electron microscopy. Compared with C rats, HT rats had significantly lower jejunal transport rates of water (2.54 +/- 0.36 versus 5.02 +/- 0.7 microL/min/microgram mucosal protein, p < 0.03), sodium (37.1 +/- 10.3 versus 102.7 +/- 18.6 mumol/min/microgram protein, p < 0.05), and glucose (1.49 +/- 0.28 versus 5.17 +/- 0.82 mumol/min/microgram protein, p < 0.02). A reduction in glycine transport was also observed but did not attain statistical significance (p = 0.058). Fructose and lysine transport was unchanged. Mucosal sucrase and lactase activities were similar in both groups, but Na,K-ATPase was significantly lower in HT rats (1.17 +/- 0.3 versus 4.03 +/- 1.5 mumol inorganic phosphate/h/mg protein; p < 0.05), with a diminution of ouabain binding sites by 41.5%. Light microscopy of jejunal mucosa from HT rats did not differ from that from C rats; electron microscopy showed mild mitochondrial swelling in HT enterocytes. A group of HT rats were treated with L-thyroxine during 4 wk; these rats had absorption rates, mucosal enzyme activities, ouabain binding, and mucosal morphology not different from C rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of hypothyroidism on jejunal mucosal function: study by in situ luminal perfusion in rats. 839 45


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