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Biomedical subjects

G Flatz

Publications and source records attributed to G Flatz.

At least 37 records · Page 2Linked to original sources
PubMed1987

X-chromosomally inherited split-hand/split-foot anomaly in a Pakistani kindred.

A Pakistani kindred comprising seven generations and 36 members with the split-hand/split-foot anomaly is described. The full expression of the trait, monodactylous or split hand and split foot, mainly of the lobster-claw type, was present in 33 males and 3 females. Other females showed a distinctly milder expression of the trait, usually in the form of partial syndactyly, metacarpal and phalangeal hypoplasia, and malformation. The distribution of the affected members in the pedigree is compatible with X-chromosomal inheritance. Hemizygous males and presumably homozygous females exhibit the typical split-hand/split-foot anomaly, whereas only a part of the obligatory heterozygous females show the milder expression. There were no associated anomalies, such as ectodermal dysplasia, cleft lip/palate, macular degeneration, malformations of the long bones or internal organs, and overt mental retardation.

Abnormalities, Multiple↗
PubMed1987

Distribution of hemoglobin E and beta-thalassemia in Kampuchea (Cambodia).

The hemoglobin type of 360 adult Cambodian subjects was determined by cellulose acetate electrophoresis and microcolumn chromatography. The following distributions and frequencies of the Hb E (beta E) and the beta-thalassemia (beta-thal) genes were found: in a group of 264 Cambodians of rural areas 153 Hb A, 83 Hb AE, 19 Hb E, and nine beta-thalassemia minor (frequency beta E 0.2292, beta-thal 0.0170). In an urban group from the capital Phnom Penh there were 68 Hb A, 21 Hb AE, four Hb E, and three beta-thalassemia minor (frequency beta E 0.1510, beta-thal 0.0156). The low frequency of beta E in the urban group is probably due to Chinese admixture. Possible causes of the observed deficiency of Hb AE heterozygotes in comparison with Hardy-Weinberg equilibrium are discussed.

Adult↗
PubMed1987

The hemoglobin E belt at the Thailand-Kampuchea border: ethnic and environmental determinants of hemoglobin E and beta-thalassemia gene frequencies.

The frequencies of the hemoglobin E gene (HBB*E) and the beta-thalassemia gene(s) (HBB*T) were determined in 890 healthy adult males from three areas at the Thai-Kampuchean border in Northeastern Thailand. The population of the three study areas differs ethnically: area I is inhabited by Khmer-speaking people, area II has an ethnically mixed population (Tai-Lao, Soui and Khmer), and area III is predominantly Lao. In view of the topographic differences in malaria endemicity in the pre-eradication era, the probands from the three study areas were divided into subgroups "hills" and "plains" according to the location of their home villages. The frequencies of HBB*T were generally low, but the difference between the HBB*E frequencies in the "hills" (0.3295) and "plains" (0.2455) subgroups was highly significant. This is interpreted as environmental effect due to selection by malaria. A "hemoglobin E belt" with HBB*E frequencies between 0.3 and 0.35 extends along the Dangraek mountain chain at the border between Thailand and Kampuchea.

Adult↗
PubMed1986

Distribution of adult lactase phenotypes in the Tuareg of Niger.

The adult lactase phenotype, lactose absorber or malabsorber, was determined using the lactose tolerance test with breath hydrogen assay in a group of Tuareg, a traditionally nomadic pastoralist population in the central Sahara. Out of a total of 118 subjects, 103 (87.3%) were lactose absorbers and 15 (12.7%) lactose malabsorbers. The frequency of the "lactase suppression gene" in this population sample was .357 (SD .043). The low frequency of lactase suppression in the Tuareg supports the hypothesis of natural selection in favor of the "lactase persistence gene" in milk-dependent nomadic pastoralist.

Adolescent↗
PubMed1986

Distribution of the adult lactase phenotypes in Turkey.

The adult lactase phenotype, lactose absorber or malabsorber, was determined using the lactose tolerance test with breath hydrogen assay in a group of young, healthy, male Turks. Out of a total of 470 subjects, 135 (28.7%) were lactose absorbers and 335 (71.3%) lactose malabsorbers. The frequency of the 'lactase suppression gene' in this population sample was 0.844 (S.D. 0.012). The frequency of lactase suppression in Turkey is intermediate between that in southeast Europe and that in agricultural Arab populations and thus compatible with a genetic cline extending from Europe to southwest Asia.

Adolescent↗
PubMed1985

Pulmonary hydrogen and methane excretion following ingestion of an unabsorbable carbohydrate: a study of twins.

Pulmonary excretion of hydrogen and methane after administration of an unabsorbable disaccharide (lactulose) was determined in 228 adult Hungarian twins, 60 monozygous (MZ) and 54 dizygous (DZ) pairs. More than 98% of the subjects (224 of 228) excreted large amounts of hydrogen between 90 and 180 min after lactulose administration. Methane excretion in the fasting state was observed in 124 of 228 of the probands (54.4%), and 68 of 228 (29.8%) produced additional methane in response to lactulose ingestion. In contrast to hydrogen production, both methane excretion and production were significantly more frequent in females than in males. In the total group, and more distinctly in females, the correlation between peak hydrogen and methane concentrations was negative. Twin concordance of fasting methane excretion and lactulose-induced methane production was near 70% in both MZ and DZ pairs. Heritability estimates of methane excretion and production based on intrapair correlation and variance were smaller than unity, and intrapair correlation coefficients were larger in twin pairs living apart than in those living in the same household. Methane excretion is comparatively frequent in the Hungarian population, and a substantial proportion of fasting methane excreters (55%) produce additional methane from lactulose. The sex difference of methane excretion appears to be characteristic of European populations. The twin data disprove regular Mendelian inheritance of methane production and are suggestive of genetic effects in a multifactorial system.

Adult↗
PubMed1984

Prevalence of primary adult lactose malabsorption in three populations of northern China.

Lactose absorption capacity was examined in 641 apparently healthy adolescents and adults (447 males and 194 females with an average age of 22.9 years and an age range of 16-46 years) using a field version of the lactose tolerance test with breath hydrogen determination. In the total sample, 89 lactose absorbers and 552 lactose malabsorbers were identified. Lactose malabsorption was most frequent in a subgroup of Han (Chinese) from northeastern China (229 of 248 subjects, 92.3%). Among 198 Mongols from Inner Mongolia, there were 174 lactose malabsorbers (87.9%). The frequency of lactose malabsorption was lowest in a group of Kazakhs, traditional herders from the northwestern region of Xinjiang (149 of 195 subjects, 76.4%). Reported symptoms of lactose intolerance were significantly more frequent in lactose malabsorbers. The findings in northern Han are similar to the reported lactose malabsorption frequency in southern (mainly overseas) Chinese, and correspond with the absence of animal milk from traditional Chinese diets. The relatively low prevalence of lactose malabsorption among the Kazakhs suggests that lactose persistence may be frequent in herding pastoralist populations of southwest Asia.

Adolescent↗
PubMed1984

A study of lactose absorption capacity in twins.

Lactose absorption capacity was determined by lactose tolerance tests with breath hydrogen determination in 102 healthy, adult, Hungarian pairs of twins in order to test monogenic Mendelian inheritance of the absorptive lactase phenotypes, lactose absorber and lactose malabsorber. Of the total, 52 pairs were monozygous (MZ) and 50 dizygous (DZ) twins of identical sex. All MZ twins were concordant with respect to lactase phenotype. Among DZ twins, the distribution of lactase phenotypes was in agreement with Hardy-Weinberg expectations derived from the frequencies of the hypolactasia gene in DZ and MZ twins, and in the general Budapest population. In the second part of the study, three commonly used methods of lactose tolerance testing, the blood glucose, the blood galactose, and the breath hydrogen tests, were compared in 49 pairs of twins concordant for lactase phenotype. Blood galactose concentration showed the greatest and only significant difference between the intrapair correlation coefficients of MZ and DZ, and no overlap between lactose absorbers and lactose malabsorbers. The intrapair correlation coefficients of peak breath hydrogen concentration in MZ and DZ twins did not significantly differ from zero, but the resolution of lactase phenotypes was satisfactory. Differences in glucose absorption and concentration in lactose absorbers and malobsorbers overlapped considerably, and among lactose absorbers correlation coefficients in DZ were higher than in MZ twins. In MZ and DZ twins, the difference in concordance and constancy of lactose intolerance symptoms was not significant.

Adolescent↗
PubMed1984

Ethnic distribution of phenylketonuria in the north German population.

Results of neonatal screening for phenylketonuria (PKU) suggest a west-east gradient of PKU gene frequency in central Europe. In order to test the hypothesis that the unexpectedly high prevalence of PKU in northwestern Germany (northern region of the FRG) is due to the migration of Germans from eastern regions of prewar Germany in the decade after World War II, grandparental origin was determined in a group of 87 pediatric PKU patients and in a control group of 210 children. Grandparents of east German origin were significantly more frequent among the PKU patients. The observed frequency distribution of grandparental subgroups was described by a theoretical distribution in order to obtain a likely set of values for the ratio between the frequency of the PKU gene in the autochthonous populations of prewar northeastern and northwestern Germany. The most likely value for the PKU gene frequency ratio was 1.37, which indicates that the prevalence for PKU in prewar northeastern Germany was almost twice as high as in the autochthonous population of the northwest.

Ethnicity↗
PubMed1984

Prevalence of primary adult lactose malabsorption and awareness of milk intolerance in Italy.

A total of 308 healthy Italian adults (192 females, 116 males; mean age 29.2 yr) were examined using a field version of the lactose tolerance test with breath hydrogen determination. Two geographical groups were formed according to the birth places of the probands' grandparents: 208 subjects from northern Italy (mainly from the regions of Piemonte, Lombardia, and Veneto) and 100 probands from Sicily. Lactose malabsorption was diagnosed in 106 subjects in group "north" (51%) and in 71 subjects in group "Sicily" (71%). Awareness of milk intolerance was more frequent in lactose malabsorbers. The incidence of diarrhea after the test dose of lactose was significantly higher in "aware" lactose malabsorbers, when compared with persons of the same group who had not experienced milk intolerance. The significant difference in lactose malabsorption frequency between northern Italy and Sicily is further evidence of a north-south gradient of lactase gene frequencies in Europe.

Adult↗
PubMed1984

Breath hydrogen test for lactose absorption capacity: importance of timing of hydrogen excretion and of high fasting hydrogen concentration.

The breath hydrogen (H2) test for lactose absorption capacity is a simple, noninvasive method for the determination of the adult lactase phenotypes, lactose absorber and malabsorber, in healthy subjects. Two breath H2 tests with a load of 50 g lactose monohydrate were performed on 25 healthy adult lactose malabsorbers in order to determine the validity of simplified versions of the test for field studies. A high variability of peak H2 excretion times, rapid changes in breath H2 concentrations and a significant correlation of intraindividual peak H2 excretion times were observed. High fasting excretion of H2 in breath was a frequent cause of misclassification of probands. It is recommended that at least three breath samples per proband should be collected in field studies of lactose absorption and that special diagnostic criteria be applied in classifying subjects with high initial H2 excretion.

Absorption↗
PubMed1984

Prevalence of primary adult lactose malabsorption in Pakistan.

Lactose absorption capacity was examined in 414 apparently healthy, adult Pakistani subjects. In a subgroup of 44 subjects, the lactose tolerance test was performed using both blood glucose and breath hydrogen determination. The remaining 370 probands were examined using a field version of the breath hydrogen test. In the total sample of 414 probands, 248 lactose malabsorbers were identified (60%). This result differs considerably from previous reports of very low frequencies of lactose malabsorption in Pakistan and neighbouring areas.

Adolescent↗
PubMed1984

Gene-dosage effect on intestinal lactase activity demonstrated in vivo.

The activities of the disaccharidases lactase, maltase, and sucrase were determined in upper jejunal biopsies of 65 healthy adult German males. The study was an attempt to demonstrate the gene-dosage effect on lactase activity expected from the presence of a "hypolactasia" (l) and a "lactase-persistence" (L) allele in the German population. In contrast to lactase/sucrase ratios, lactose/maltose ratios showed a trimodal distribution in proportions of presumed genotypes LL, Ll, and ll compatible with Hardy-Weinberg equilibrium. The frequency of homozygotes ll (13.8%) was similar to the average frequency of lactose malabsorbers in Germany reported in the literature. The importance of considering the lactase gene-dosage effect in population studies of lactase activity is discussed.

Adult↗
PubMed1983

Prevalence of primary adult lactose malabsorption in Hungary.

Lactose absorption capacity was estimated in 820 apparently healthy, well nourished, Hungarian adults and adolescents (560 females, 260 males, aged 16-54 years) using a field version of the lactose tolerance test with breath hydrogen determination. The test identified 497 lactose absorbers with low, and 323 lactose malabsorbers with high hydrogen excretion 120-150 min after an oral load of 50 g lactose. The prevalence of lactose malabsorption in the general Hungarian sample (n = 535) was 37%. In subgroups from the western and eastern Hungarian plains, frequency of lactose malabsorption reached almost 30%. It tended to be higher in Upper Hungary (ca. 40%) and in subjects stemming from former Hungarian areas in the Carpathian bend. Lactose malabsorption in a Hungarian ethnic subgroup, the Matyo (n = 172), did not differ significantly from that in the general population. Among Romai ("Gypsies", n = 113), the prevalence of lactose malabsorption was significantly higher (56%). Awareness of milk intolerance was significantly more frequent, and severe symptoms of lactose intolerance during the test occurred almost exclusively in lactose malabsorbers.

Adolescent↗