Biomedical subjects

S D Flatz

Publications and source records attributed to S D Flatz.

At least 19 recordsLinked to original sources

PubMed1990

Mitotic disturbance associated with mosaic aneuploidies.

The association of various unsystematic aneuploidies with premature centromere division (PCD) was observed in a patient with conspicuous clinical features and combined immunodeficiency. Trisomies and monosomies of almost all autosomes and gonosomal aberrations were found separately or in combination in a majority of the proband's lymphocytes and fibroblasts. The chromosome number varied from 44 to 50. A high proportion of the metaphases showed PCD or had the appearance of C-anaphases. These findings probably represent a new mutant affecting mitosis and causing mosaic aneuploidies.

Aneuploidy↗

PubMed1989

DNA haplotypes and frameworks linked to the beta-globin locus in an Austro-Asiatic population with a high prevalence of hemoglobin E.

DNA haplotypes (HT) and frameworks (FW) linked to the beta-globin locus were determined by restriction fragment analysis using eight restriction enzymes on chromosomes bearing the Hb A gene (HBB*A) or the HbE gene (HBB*E) in the So, an Austro-Asiatic population of northeast Thailand with an HBB*E frequency near 0.5. All HBB*E genes were present with FW2, and only two haplotypes were observed (25 HT 27-2, -+- +-; 10 HT 41-2, +----++-). In a control group from the general population of Northeast Thailand the HT distribution was more diverse, and 2 of 20 HBB*E genes were present in FW 3. High frequencies of HBB*E in FW 3 in Southeast Asia are apparently limited to the Khmer population of Cambodia. There were no differences in the hematologic parameters in subjects homozygous for HBB*E/FW2 or HBB*E/FW3.

DNA↗

PubMed1988

Frequency of deletional types of alpha-thalassemia in Kampuchea.

The frequency of deletional types of alpha-thalassemias in the Khmer population of Kampuchea (Cambodia) was estimated using DNA techniques. Among 58 healthy adult Kampucheans from rural areas, 17 had alpha-globin gene anomalies. There were 14 heterozygotes and two homozygotes for alpha(+)-thalassemia; the remaining test subject carried a deletion of both alpha-globin genes (alpha(0) -thalassemia of the Southeast Asian type) on one chromosome 16, and triple alpha-globin genes on the other. All of the 18 alpha(+)-thalassemia deletions were of the -alpha 3.7 type (17 subtype I, 1 subtype II). The restriction pattern obtained with the enzyme RsaI and comparison of the intensity of hybridization with alpha-globin and beta-globin gene probes yielded no evidence of total deletion of the alpha-gene complex. The prevalence of deletional alpha(+)-thalassemia in Kampuchea is higher, and that of alpha(0)-thalassemia is lower than in neighbouring Thailand.

Blotting, Southern↗

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↗

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

Segregation of two independent chromosomal translocations in one family.

A family with two independent reciprocal translocations t(3;19) and t(16;22) is described. The proband, a 4-week-old male, was phenotypically conspicuous with multiple congenital anomalies. Cytogenetic examination revealed a balanced reciprocal translocation (3;19) and a supernumerary small marker chromosome. His mother carried two balanced reciprocal translocations, the one found in the proband and a reciprocal translocation (16;22). The maternal grandmother and a maternal uncle were identified as carriers of a single translocation (16;22). The findings in the family members permitted the identification of the proband's marker chromosome as a derivative chromosome 22 resulting in partial trisomy 16 and 22.

Chromosome Aberrations↗

PubMed1984

Optiz trigonocephaly syndrome: report of two cases.

We report two patients with Opitz trigonocephaly syndrome. Both children showed the pattern of abnormal findings characteristic of this syndrome, including trigonocephaly, upslanted palpebral fissures, inner epicanthic folds, broad alveolar ridges, small chin, short neck with loose skin, muscular hypotonia and cardiac defect. An 8-week-old girl had multiple gingival frenula, brachydactyly, syndactyly of toes and anal stenosis in addition, while a boy who died at 28 h from cardiac failure showed multiple joint contractures, cryptorchidism and renal cortical cysts.

Abnormalities, Multiple↗

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↗

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↗

PubMed1982

[Fragile X chromosome and X-linked mental retardation (author's transl)].

In males affected by a special form of X-linked mental retardation a characteristic chromosomal abnormality can be demonstrated, - i.e. a fragile site on the long arm of the X chromosome, fra(X) (q27 or 28) (marker-X chromosome). Male carriers are physically normal, but in most cases show macroorchidism. The demonstration of the marker-X chromosome requires special cell culture conditions, above all a folic acid-deficient medium. The frequency of cells with fragile X chromosome varies interindividually, ranging from 2 to 50%. In female heterozygous carriers the number of cells with fra(X) decreases with age and cannot be demonstrated in some cases. Distribution and frequency of X-linked mental retardation with marker-X chromosome and macro-orchidism are discussed, as well as possibilities of prenatal diagnosis of this disorder.

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 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

Preferential maternal derivation in inv dup(15): analysis of eight new cases.

Eight patients are reported with a de novo extra inverted duplicated chromosome 15. The abnormal chromosome was considered to be the same in all cases, but its precise delineation remained uncertain and was defined as either 15pter leads to 15q12::15q12 leads to 15pter or 15pter leads to 15q11::15q13 leads to 15pter. Analysis with various techniques of the satellite regions of the bisatellited chromosomes demonstrated maternal derivation in six and paternal derivation in one of the seven families. A non-sister chromatid exchange between the two homologous chromosomes 15 is considered a likely origin of the inv dup(15) in the cases with maternal derivation; in the only case of paternal derivation, however, the abnormal chromosome originated from one single chromosome 15. The clinical findings confirm that patients with inv dup(15) have mental and developmental retardation and are frequently affected by seizures, while severe physical malformations are absent.

Abnormalities, Multiple↗

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↗