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Biomedical subjects

G T Nurse

Publications and source records attributed to G T Nurse.

At least 19 recordsLinked to original sources
PubMed1991

Deletion in erythrocyte band 3 gene in malaria-resistant Southeast Asian ovalocytosis.

Southeast Asian ovalocytosis (SAO) is a hereditary condition that is widespread in parts of Southeast Asia. The ovalocytic erythrocytes are rigid and resistant to invasion by various malarial parasites. We have previously found that the underlying defect in SAO involves band 3 protein, the major transmembrane protein, which has abnormal structure and function. We now report two linked mutations in the erythrocyte band 3 gene in SAO: (i) a deletion of codons 400-408 and (ii) a substitution, A----G, in the first base of codon 56 leading to substitution of Lys-56 by Glu-56. The first defect leads to a deletion of nine amino acids in the boundary of cytoplasmic and membrane domains of band 3. This defect has been detected in all 30 ovalocytic subjects from Malaysia, the Philippines, and two unrelated coastal regions of Papua New Guinea, whereas it was absent in all 30 controls from Southeast Asia and 20 subjects of different ethnic origin from the United States. The Lys-56----Glu substitution has likewise been found in all SAO subjects. However, it has also been detected in 5 of the 50 control subjects, suggesting that it represents a linked polymorphism. We conclude that the deletion of codons 400-408 in the band 3 gene constitutes the underlying molecular defect in SAO.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1990

Molecular defect of the band 3 protein in southeast Asian ovalocytosis.

BACKGROUND: Southeast Asian ovalocytosis is a form of hereditary elliptocytosis in which the red cells are rigid and resistant to malaria invasion. The underlying molecular defect is unknown. METHODS AND RESULTS: We studied the red cells of 54 patients with ovalocytosis and 122 normal controls. We found that ovalocytes contain a structurally and functionally abnormal band 3 protein, the principal transmembrane protein of red cells. The structural lesion of ovalocyte band 3 was revealed by limited proteolytic cleavage of the protein, which produced fragments of abnormal size that were derived from the cytoplasmic domain of the protein. The structural lesion was present in all the subjects with ovalocytosis but none of the controls. This region of band 3 serves as the principal binding site for the membrane skeleton, a submembrane protein network composed of ankyrin, spectrin, actin, and protein 4.1. The structural defect is dominantly inherited, being tightly linked with the inheritance of ovalocytosis (the probability of linkage is in excess of 10 million to 1). Ovalocyte band 3 bound considerably more tightly than normal band 3 to ankyrin, which connects the membrane skeleton to the band 3 protein. This tight binding of ovalocyte band 3 to the underlying skeleton containing ankyrin was directly confirmed in intact cells by the finding that ovalocyte band 3 had markedly reduced lateral mobility in the membrane. CONCLUSIONS: The red cells in Southeast Asian ovalocytosis carry a structurally and functionally abnormal band 3 protein. This molecular defect may underlie the increased rigidity of the red cells and their resistance to invasion by malaria parasites.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1990

Geographical distribution of subjects seropositive for human T-cell leukemia virus type 1 in Papua New Guinea.

Of 1471 sera collected from 1986 to 1989 in Papua New Guinea (PNG), 2.2% were found to be positive for anti-HTLV-1 antibody by successive particle agglutination and immunofluorescence tests. The seropositive rate varied in different provinces and was higher in the coastal areas of the main island and in neighboring small islands than in the highlands of PNG. The frequency of HTLV-1 infection of children was higher, but the age-dependent increase in antibody positivity, generally observed in other HTLV-1 endemic areas of the world, was not clear in PNG. No difference was observed in antibody prevalence in males and females in this study.

Adolescent↗
PubMed1989

Province of origin of hepatitis B surface antigen carriers among blood donors in Port Moresby.

A paper published in the Medical Journal of Australia in 1972 gave a breakdown of Port Moresby blood donors by HBS Ag carrier status and area of origin. It has lately become possible to test whether such geographical subsamples provide reliable evidence of the carrier status in the home areas, and it appears that, except for the Islands provinces, they do not. Traditional lifestyles conduce to the maintenance and spread of the virus, which is much more prevalent in the provinces than in the capital.

Blood Donors↗
PubMed1987

Structural relationships between human erythrocyte sialoglycoproteins beta and gamma and abnormal sialoglycoproteins found in certain rare human erythrocyte variants lacking the Gerbich blood-group antigen(s).

The human erythrocyte membrane sialoglycoproteins beta and gamma are important for the maintenance of the discoid shape of the normal erythrocyte. In this paper we show that the human erythrocyte sialoglycoproteins beta and gamma (hereafter called beta and gamma) are structurally related. Rabbit antisera produced against purified beta and beta 1 and rendered specific to the cytoplasmic portion of these proteins also react with the cytoplasmic portion of gamma. Some human anti-Gerbich (Ge) sera react with the extracellular portion of both beta and gamma. This reactivity is shown to be directed towards a common epitope on beta and gamma. However, most anti-Ge sera do not react with beta, but react with an extracellular epitope only present on gamma. All individuals who lack the Ge antigens lack beta and gamma. In some cases abnormal sialoglycoproteins are present in the erythrocytes, and these are shown to be structurally related to beta and gamma. Rabbit antisera raised against the purified abnormal sialoglycoprotein from a Ge-negative erythrocyte type reacted with the cytoplasmic portion of both beta and gamma. Unlike normal beta and gamma, the abnormal sialoglycoproteins found in Ge-negative erythrocytes migrate as a diffuse band on SDS/polyacrylamide-gel electrophoresis. Studies using endoglycosidases suggest that the diffuse nature of these bands results from carbohydrate heterogeneity and that the abnormal sialoglycoproteins contain N-glycosidically linked oligosaccharides with repeating lactosamine units. Such polylactosamine chains are not present on normal beta or gamma.

Blood Group Antigens↗
PubMed1987

Sero-genetic studies on the Ambo of Namibia.

The Ambo are the largest population group of Namibia/South West Africa and consist of seven geographical and sociopolitical entities speaking different dialects of a common language. Nearly 600 individuals representing all the dialect groups were tested for 23 sero-genetic systems: the results reveal no evidence of significant San admixture and unusual alleles suggest an affinity with the Herero which confirms oral traditions of a common origin. Genetic distance measurements indicate that the Dama may also have a connection with these peoples and it is probable that most of the Bantu-speaking Negroes of Namibia/South West Africa come from the same stock.

Black People↗
PubMed1986

Alpha-thalassemia in Papua New Guinea.

A study of the distribution of alpha-thalassemia in Papua New Guinea (PNG) was carried out by DNA analysis. A total of 664 DNA samples were screened for alpha-thalassemia 2 and alpha-thalassemia 1 caused respectively by either deletion of one or both of the duplicated alpha-globin genes. alpha-Thalassemia 2 was detected in high frequencies in coastal and lowland regions where malaria has been holo- to hyperendemic but in low frequencies in non-malarious highland regions. The highest frequency was observed in the north coast of PNG. The distribution of alpha-thalassemia 2 seems to be in accordance with other conditions such as ovalocytosis and G6PD deficiency which are also prevalent in this population, suggesting that they may interact in protection against malaria. However, it appears to be negatively correlated with beta-thalassemia and alpha-thalassemia 1, the latter being extremely rare in this population. Analysis of the types and subtypes of the single alpha-globin gene deletion revealed a predominance of the -alpha 4.2 type in general, except in some regions in the south where the -alpha 3.7 type is prevalent. The -alpha 3.7 I subtype is the common form of the -alpha 3.7 deletion in the PNG mainland. The -alpha 3.7 III subtype, previously reported to be unique in Melanesians and Polynesians, was detected in an offshore island of PNG. However, this subtype is very rare in Melanesians from the PNG mainland.

Chromosome Deletion↗
PubMed1985

Rett's syndrome.

Explore the source record for details and available documents.

Ataxia↗
PubMed1985

Homozygosity for the delta-chain variant haemoglobin A2' (HbB2) (delta 16 Gly----Arg).

A healthy 20-year-old woman, belonging to the Kgalagadi tribe of Botswana, has been found to possess a variant Haemoglobin A2 as her only minor haemoglobin component. Fingerprinting and amino-acid analysis have shown that it is Haemoglobin A2' (delta 16 Gly----Arg). The one parent available for study is heterozygous for the Hb delta A2' allele and the variant haemoglobin accounts for 3% of the total haemoglobin in the proband. It is reasoned that the proband is, therefore, homozygous for the Hb delta A2' allele. No haematological abnormalities were evident.

Adult↗