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Biomedical subjects

G Flatz

Publications and source records attributed to G Flatz.

At least 55 records · Page 3Linked to original sources
PubMed1983

Temporary depression of lactase activity by thyroxine in suckling rats.

The present study was performed in order to clarify controversies concerning the effect of thyroxine on lactase activity in young mammals. Lactase activity was determined in suckling rats with two reference systems (protein and DNA) after one and three thyroxine injections (0.2 mg/100 g body weight). In comparison with control animals lactase activity was decreased after thyroxine administration. The thyroxine effect was dosage-dependent: three injections caused a more profound and prolonged depression of lactase activity. In both thyroxine-treated groups lactase activity returned to age-specific normal levels before the low lactase activity of adult rats was attained. The transient thyroxine-induced changes of lactase activity were similar to the reference parameters protein and DNA.

Animals↗
PubMed1983

Distribution of adult lactase phenotypes in Bedouins and in urban and agricultural populations of Jordan.

Lactose tolerance tests with breath hydrogen determination identified 39 lactose malabsorbers among 162 Jordanian Bedouins (24%), and 111 lactose malabsorbers among 148 subjects from the urban/agricultural zone of western Jordan and Palestine (75%). This highly significant difference supports the hypothesis that milk dependence in nomadic desert populations resulted in selective pressures in favour of the lactase persistence gene. Within the urban/agricultural zone which extends from the desert border in Jordan to the Mediterranean shore, a significant increase in the frequency of lactose malabsorbers (and hypolactasia gene frequencies) from east to west was observed. The suggested genetic cline is problably due to migration from the desert populations to the agricultural zone.

Adolescent↗
PubMed1982

Beja and Nilotes: nomadic pastoralist groups in the Sudan with opposite distributions of the adult lactase phenotypes.

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.

Adolescent↗
PubMed1982

Distribution of physiological adult lactase phenotypes, lactose absorber and malabsorber, in Germany.

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.

Adolescent↗
PubMed1982

Distribution of human adult lactase phenotypes in the population of Austria.

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.

Adolescent↗
PubMed1982

Lactose absorption and malabsorption in healthy German children: improved phenotypic resolution by simultaneous determination of breath hydrogen and carbon dioxide.

A total of 124 apparently healthy German children aged 8 to 10 years were examined for lactose absorption employing the breath hydrogen test with multiple breath collection. Analysis of the maximal change of breath hydrogen concentration (delta maxH2) 110 and 150 min after a lactose load of 30 g failed to yield a bimodal distribution separating lactose absorbers and malabsorbers as observed in adults. Comparison with an adult control group of 120 subjects showed that the mean CO2 concentration was significantly lower and the coefficient of variation was considerably higher in the breath samples of the children. The difference between the highest and the lowest CO2 concentration in the three samples obtained from each individual was also significantly higher in the group of children. Normalizing the children's H2 concentration values to the mean CO2 concentration in the total group (3.04%) yielded a bimodal distribution of the delta maxH2 values. Of 124 children, 18 were identified as lactose malabsorbers. The 14.5% frequency is similar to that observed in German adults.

Air↗
PubMed1982

Effect of acetylsalicylic acid on symptoms and hydrogen excretion in the disaccharide tolerance test with lactose or lactulose.

Prostaglandins play a role in the pathogenesis of symptoms of food intolerance. An alleviation of lactose intolerance by premedication with the prostaglandin-synthesis inhibitor acetylsalicylic acid (ASA) has been reported. We studied the effect of 900 mg of ASA and of a glucose placebo on disaccharide intolerance symptoms and on breath hydrogen (H2) excretion in 16 healthy adult males 12 of whom were lactose malabsorbers and received 50 g of lactose 30 to 40 min after ASA; the remaining four were lactose absorbers and received 30 g of lactulose. Premedication with ASA had no significant effect on the severity and duration of intolerance symptoms and on the timing of H2 excretion. In contrast, the maximal breath H2 concentration and the total H2 excretion were significantly increased after ASA administration. We conclude that prostaglandins are of minor importance in causing the usually moderate symptoms of disaccharide intolerance. Prostaglandin-synthesis inhibition by ASA may reduce the motility of the colon thereby permitting more colonic gas (derived from unabsorbed carbohydrates) to be absorbed and excreted.

Aspirin↗
PubMed1982

Distribution of human adult lactose phenotypes in Egypt.

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.

Adolescent↗
PubMed1981

Distribution of the lactase phenotypes in the population of the Democratic Republic of the Sudan.

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.

Adult↗
PubMed1981

Population screening for the human adult lactase phenotypes with a multiple breath version of the breath hydrogen test.

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.

Adult↗
PubMed1980

Population screening for beta-thalassaemia.

The graphic recording of time to 50% haemolysis in a glycerine-saline solution is a simple, reproducible method of determining erythrocyte osmotic fragility. Studies on a normal population yielded an upper limit of normal of 90 s. In 250 healthy males from Northern Thailand all 19 with beta-thalassaemia minor had abnormal osmotic indices, and the value of the test was confirmed in beta-thalassaemia heterozygotes in Europe. Of 23 patients with iron deficiency 18 had abnormal osmotic indices. However, this is not thought likely to be a significant source of false positives in the screening of populations at risk of haemoglobinopathies but in whom iron deficiency is rare.

Female↗
PubMed1980

Properdin factor B polymorphism in Afghanistan.

The distribution of properdin factor B (Bf) phenotypes and gene frequencies was studied in four populations of Afghanistan: Hazaras, Pushtoons, Tajiks and Usbeks. Significant differences between Usbeks and the other three ethnic groups were observed. The distribution of gene frequencies in Usbeks was similar to that of European populations.

Afghanistan↗
PubMed1980

Intestinal disaccharidase activities and activity ratios in a group of 60 adult German subjects.

Lactase, maltase and sucrase activities were determined in samples of jejunal mucosa obtained by suction biopsy from 60 healthy adult German males. Primary adult hypolactasia ("lactase deficiency") was found in 8 subjects (13%). Maltase:lactase and sucrase:lactase activity ratios were significantly higher in post-weaning hypolactasia than in adult lactase persistence. Sources of variation in disaccharidase activities measured in biopsy tissue homogenates are discussed.

Adult↗
PubMed1979

Hemoglobin Suan-Dok (alpha 2 109 (G16) Leu replaced by Arg beta 2): an unstable variant associated with alpha-thalassemia.

An abnormal hemoglobin variant was detected in a seven-year old Thai girl. The clinical and hematological pictures were indistinguishable from hemoglobin H disease. Upon cellulose acetate electrophoresis at pH 8.5 an abnormal hemoglobin variant was found together with hemoglobins A and H. The variant moved slightly behind HbF and amounted to approximately 9%. Globin chain synthesis studies of peripheral blood reticulocytes incubated with tritiated leucine revealed that the total radioactivity ratio alpha-chain + variant alpha-chain/beta-chain was 0.59, while the ratio variant alpha-chain/beta-chain was 0.12. The variant hemoglobin was somewhat unstable under heat denaturation and in the isopropanol test. Structural studies by component isolation, globin chain separation, peptide mapping and aminoacid analysis of abnormal peptides showed that the leucine residue 109 of the alpha-chain was replaced by arginine. This hemoglobin mutant has not been described before and is named Hemoglobin Suan-Dok.

Adult↗