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 purpose of this study was to compare breath hydrogen tests after oral lactose ingestion in nonoperated subjects and postgastrectomy patients. Simultaneous oral lactose tolerance tests and breath hydrogen tests were performed in 50 subjects. Twenty of the 30 subjects without prior gastric surgery had normal lactase activities and low breath hydrogen concentrations. The other 10 subjects had low lactase levels and increased breath hydrogen concentrations. The remaining 20 subjects had prior gastric surgery. Seven of these had normal lactase activities, no history of milk intolerance and low breath hydrogen concentrations. Two of the postgastrectomy patients had low intestinal lactases, milk intolerance, and high breath hydrogens. The remaining 11 postgastrectomy patients had normal intestinal lactases but high breath hydrogens. Eight of the 11 had milk intolerance while two of the other three had not consumed milk since childhood. From these studies the following conclusions can be reached: 1)a low lactose breath hydrogen test in the postgastrectomy subject correctly identifies the individual with normal lactase activity. However, high breath hydrogen responses, may be found in either those with lactase deficiency or normal lactase activity. 2) Lactose malabsorption would appear to explain the milk intolerance in the postgastrectomy patient with normal lactase activity.
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PMID:Breath hydrogen test after oral lactose in postgastrectomy patients. 677 92

Lactose tolerance tests with conventional blood glucose determination and with breath hydrogen analysis after storage of breath samples in aluminium aerosol cans were simultaneously performed in 60 healthy adult subjects. Both tests were equally reliable in the diagnosis of the lactase phenotype in healthy persons. In subjects with decreased glucose metabolism the breath hydrogen test seems to be more reliable than the blood glucose test. Provisions for storing breath samples for up to several weeks, avoidance of invasive procedures and insensitivity of glucose absorbed during the test make the present version of the lactose tolerance test with breath hydrogen determination particularly suitable for population studies.
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PMID:Population screening for the human adult lactase phenotypes with a multiple breath version of the breath hydrogen test. 678 75

The distribution of the adult lactase phenotypes, lactose absorption, and lactose malabsorption, was determined by a field version of the hydrogen breath test for disaccharide absorption in a sample of 563 subjects residing in the Democratic Republic of the Sudan. Relatively high proportions of lactose absorption were found in the northern nomadic groups who rely heavily on dairying for their livelihood. Residential Nile valley populations revealed intermediate frequencies of the two phenotypes whereas the negroid populations of the south exhibited a high prevalence of lactose malabsorption irrespective of their economic status with respect to agriculture and dairying. The frequency of the "hypolactasia allele" ranged between 0.6 and 0.87 in the major regional groups.
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PMID:Distribution of the lactase phenotypes in the population of the Democratic Republic of the Sudan. 678 76

A sample of volunteers from the north-west of Papua New Guinea has been tested for persistent high intestinal lactase activity by measuring the breath hydrogen content before and after the administration of a preparation containing 50 g lactose. Eight of 35 persons were found to be absorbers of lactose. In common with other recent studies, this proportion establishes that the polymorphism occurs on the island, though the frequency of absorbers is nowhere high. The breath hydrogen method of estimating status has been shown to be capable of providing unequivocal, convincing results in the field.
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PMID:Persistent high intestinal lactase activity in Papua New Guinea. The breath hydrogen test in a Sepik population. 679 22

Lactose absorption was studied in 570 health adolescent and adult males in Egypt. Employing a field version of the noninvasive hydrogen breath test, 156 (27.4%) lactose absorbers and 414 (72.6%) lactose malabsorbers were identified. The age-specific prevalence of the lactose phenotypes indicated that lactase repression is complete at the age of 14 years in Egyptians. The regional distribution showed significant differences between the Nile Delta and the northern and southern part of Upper Egypt. The existence of a north-south gradient of decreasing frequencies of the hypolactasia gene from the Nile Delta to the Sudan is suggested.
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PMID:Distribution of human adult lactose phenotypes in Egypt. 680 27

Lactose tolerance tests with breath hydrogen determination were performed on 585 apparently healthy adolescents and adults in the Democratic Republic of the Sudan. Out of the total, 303 probands belong to the tribal group Beja, traditional nomadic pastoralists in the desert zone between the Nile and the Red Sea. The 282 Nilotes (mainly Dinka) are members of seminomadic cattle breeding tribes in the south of the Sudan. In both populations milk consumption is substantial but only in the Beja true milk dependence, sufficient to result in selective pressures in favour of the lactase persistence allele, is likely to exist. The proportion of lactose malabsorbers was 16.8% in the Beja and 74.5% in the Nilotes. The high prevalence of lactose malabsorption among the Nilotes fits into a converging gradient of lactase gene frequencies along the Nile Valley. The Beja are the first nomadic desert population in North Africa in whom a high prevalence of lactase persistence has been demonstrated on a numerically sufficient sample.
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PMID:Beja and Nilotes: nomadic pastoralist groups in the Sudan with opposite distributions of the adult lactase phenotypes. 681 Jul 4

A total of 1805 apparently healthy, adult and adolescent Germans (1572 males and 233 females with a mean age of 20.3 years) were examined for lactose absorption capacity employing a field version of the breath hydrogen (H2) test. The diagnostic parameter, maximal change of breath hydrogen concentration 120 or 150 min after a load of 50 g lactose, showed a bimodal distribution, separating lactose absorbers (n = 1537, 85.2%) and lactose malabsorbers (n = 268, 14.8%). The distribution of the adult lactase phenotypes was independent of age, sex, and educational status. The incidence of gastrointestinal symptoms after lactose administration demonstrated the incongruity of lactose malabsorption and lactose intolerance. In addition to grouping by residence, the probands were classified according to the birthplaces of their grandparents in order to reconstruct the distribution pattern of the lactase phenotypes prior to World War I, a period of relative population stability. Considerable differences in the frequency of lactose malabsorption were found in regions corresponding to traditional ethnic groups within the German population: northwest Germany 6-9%, west and south 13-14%, southwest 23%, east (including formerly German territories east of rivers Oder and Neisse) 22%. These differences are discussed with reference to population history. The present fairly even distribution of the lactase phenotypes in West Germany is the result of internal migrations at the end of World War II.
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PMID:Distribution of physiological adult lactase phenotypes, lactose absorber and malabsorber, in Germany. 681 21

A total of 528 unrelated, apparently healthy, adult and adolescent Austrians (270 females, 258 males, mean age 22.1 years) were examined for lactose absorption capacity employing a noninvasive field test based on breath hydrogen (H2) determination. Subjects exhibiting a change of breath hydrogen concentration of less than 15 volumes per million (vpm) after a load of 50 g lactose (n = 422) were classified as lactose absorbers, 106 probands (20.1%) showing increases of breath hydrogen concentration between 16 and 111 vpm were diagnosed as lactose malabsorbers. The distribution of the lactase phenotypes was independent of age and sex. Intolerance symptoms after lactose administration were significantly more frequent in lactose malabsorbers. Grouping of probands according to the birth-places of their grandparents revealed significant differences in the distribution of the lactase phenotypes in East and West Austria (East 25%, West 15% lactose malabsorbers). These differences are discussed in the light of the population history of these regions.
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PMID:Distribution of human adult lactase phenotypes in the population of Austria. 681 22

The aim of this study was to determine the incidence of lactose malabsorption in healthy, adult Australian Aborigines. Malabsorption of lactose was measured in 45 full blooded Aboriginal subjects and 37 nonAboriginal multiracial controls using the breath hydrogen method. 84% of the Aboriginal subjects were found to be lactose malabsorbers and 64% developed abdominal pain or diarrhea. In the control subjects, 20% were found to be lactose malabsorbers and all of these developed symptoms of diarrhea. The results provide strong evidence that Australian Aborigines, in common with most human adults, are lactase deficient.
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PMID:Lactose malabsorption in Australian Aborigines. 682 86

In adults with the irritable bowel syndrome who had no history of milk intolerance, the prevalence of lactase deficiency and the value of lactose restriction were determined. Eighty subjects with the irritable bowel syndrome who were white, non-Jewish, and of northern-western European background were screened for lactase deficiency by means of the hydrogen breath test. Lactase deficiency was found in 5 of the 80 subjects with the irritable bowel syndrome and in 6 of the 100 subjects without intestinal symptoms who were of comparable ethnic background. After exclusion of milk from the diet, three of the five subjects with lactase deficiency and the irritable bowel syndrome had partial to complete relief of symptoms for 3 weeks, and two of these had sustained relief for 1 year (one with complete and one with 75% improvement). Lactase deficiency was found to be a relatively uncommon cause of irritable bowel symptoms among non-Jewish whites who are of northern-western European background.
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PMID:Irritable bowel syndrome. Role of lactase deficiency. 684 84


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