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Biomedical subjects

M Ramsay

Publications and source records attributed to M Ramsay.

At least 163 records · Page 9Linked to original sources
PubMed1988

Resolution of neurological symptoms in high-risk infants during the first two years of life.

115 high-risk infants were identified and followed prospectively over the first 24 months of life. All infants underwent neurological assessments at 12 and 24 months and developmental assessments at six and 12 months. Approximately one-quarter of the infants were considered to be 'neurologically suspicious' at 12 months of age, of whom slightly more than one-half were deemed normal by 24 months. Children who were classified as being either normal or abnormal at 12 months were highly likely to have their classification confirmed at 24 months. Abnormal and suspicious neurological outcomes at 12 and 24 months were inversely correlated with birthweight and were not affected by the infants being given early physical therapy. Children who were suspicious at 12 months and who either remained suspicious or became abnormal at 24 months had lower personal-social quotients at six and 12 months and lower hearing-speech quotients at 12 months than the suspicious children who became normal.

Birth Weight↗
PubMed1988

Alpha-globin gene cluster haplotypes in the Kalahari San and southern African Bantu-speaking blacks.

Alpha-globin gene cluster haplotypes were determined in Southern African San and negroid populations. Significant differences (P less than .01) between the two groups were found at three of the nine loci in the cluster. The most striking difference, however, was the relatively low level of variation found in the San (alpha alpha)-associated haplotypes and the high level in the SA blacks. This trend was also observed for the 3' hyper-variable region. Nineteen different haplotypes were identified among the 36 haplotypes studied in the black population, but only seven different ones were found among the 37 haplotypes in the San; five were common to both populations. The common San haplotype, (+--MPZ+---), had a frequency of .57 in the San and .11 in the black population; the common SA black haplotype, (---MZ----), occurred at a frequency of .17 but was absent in the San. In the SA black population significant linkage disequilibrium is present between five of the RFLP loci, including the extreme 5' and 3' markers, confirming the absence of a recombination hot spot in the alpha-globin gene cluster.

Africa, Southern↗
PubMed1988

XX true hermaphroditism in southern African blacks: an enigma of primary sexual differentiation.

A high incidence of 46,XX true hermaphroditism exists among southern African blacks. The gonadal distribution and clinical presentation of 38 patients are described. The aim of our study on 11 families with histologically proven XX true hermaphroditism was to determine whether a common genetic or environmental etiology could be identified. Pedigree analysis excluded the presence of a simple inheritance pattern, and no constant environmental factors could be implicated. Hybridization studies with Y chromosome--specific probes (pDP132, pDP61, pDP105, pDP31, pDP97, and pY431-HinfA) excluded the presence of a large portion of Yp in these patients. It is possible that smaller portions of the Y chromosome or one or more X-linked or autosomal mutations, either interacting and/or with incomplete penetrance, are present.

Black People↗
PubMed1988

Developmental outcome in very low birth weight infants 6 to 36 months old.

A cohort of 78 infants weighing less than 1500 g at birth was followed prospectively to determine the impact of birth weight, age of assessment, and skill area on their developmental performance. Five skill areas were tested using the Griffiths Mental Scales of Development at 6, 12, 24, and 36 months of age. Infants were divided into three birth weight groups: less than 750 g, 750-1000 g, and 1001-1500 g. A significant age and skill interaction was found, with the locomotor and eye-hand skills decreasing consistently over time, and the personal-social and hearing and speech skills initially decreasing and then rising from 12 to 36 months. Infants born at less than 1000 g consistently performed more poorly than those born at 1001-1500 g. Explanations for the variation in scores and the implications of these findings to the evaluation of low birth weight infants are discussed.

Child Development↗
PubMed1987

Non-insulin-dependent diabetes mellitus and the 5' hypervariable region of the insulin gene in two South African Indian families.

The hypervariable region 5' to the human insulin gene has been characterised in two South African Indian families, each having two generations of individuals affected with non-insulin-dependent diabetes mellitus (NIDDM). Southern blot analysis, with the restriction endonuclease Pvu II and plasmid phins 310 as a probe, was used. In family 1, class 1 alleles (0.87, 0.79, 0.72 and 0.68 kilobase (kb)) were found at this locus but no linkage with NIDDM was shown. In family 2 a class 3 (2.51 kb) and two class 1 alleles (0.89, 0.76) were found. The 0.89 kb allele appears to be segregating with NIDDM in this family.

Adult↗
PubMed1987

Globin gene-associated restriction-fragment-length polymorphisms in southern African peoples.

The combination of polymorphic restriction-enzyme sites in the 3' region of the beta-globin gene cluster shows very little variation in southern-African Bantu-speaking black and Kalahari !Kung San populations. The sites of the 5' region, on the other hand, show marked variation, and two common haplotypes are present--the "Negro" type (- - - - +) and the "San" type (- + - - +)--in frequencies of .404 and .106, respectively, in the Bantu-speakers and .262 and .405, respectively, in the San. Twenty of 23 beta s-associated haplotypes in southern-African Bantu-speaking black subjects were the same as that found commonly in the Central African Republic (CAR)--i.e., the "Bantu" type--a finding providing the first convincing biological evidence for the common ancestry of geographically widely separated speakers of languages belonging to the Bantu family. The (-alpha) haplotype has a frequency of .21 in the Venda, .07 in both the Sotho-Tswana and the Nguni, and .06 among the !Kung San. These data are interpreted in the light of Plasmodium falciparum malaria selection and population movements in the African subcontinent.

Africa, Southern↗
PubMed1987

A unique dicentric X;Y translocation with Xq and Yp breakpoints: cytogenetic and molecular studies.

A 32-year-old woman presented with secondary amenorrhea and infertility. She was of normal height and her breasts were well developed, but she had streak gonads; there were no signs of virilization, and she showed no somatic stigmata of Turner syndrome. Chromosome analysis revealed a dicentric X;Y translocation with Xq and Yp breakpoints. Centromeric banding demonstrated a Y centromere and a "suppressed" X centromere. The karyotype of the patient was interpreted as 46,X,t(X;Y)(q22;p11). The Yp breakpoint was confirmed by DNA-hybridization studies with six probes detecting Y-specific sequences. These DNA-hybridization studies were consistent with the presence of the long arm, centromere, and much of the proximal short arm of the Y. The Y-DNA studies of this female also revealed the absence of the distal short arm of the Y chromosome, to which the testis-determining factor has previously been localized.

Adult↗
PubMed1986

A Taq 1 gamma-globin DNA polymorphism: an African-specific marker.

The allele frequency of a Taq 1 gamma-globin gene restriction fragment length polymorphism (RFLP) is reported in ten population groups. In four African populations the 3.0 kb RFLP is common (50/132 beta A chromosomes), whereas it is completely absent in six European/Asian populations (0/277 beta A chromosomes). This Taq 1 RFLP is thus a specific African population marker.

Africa↗
PubMed1986

The haematological puzzle of Hb J Cape Town is partly solved.

Molecular studies have shown that the mutation giving rise to Hb J Cape Town (alpha 92 arg----gln) is situated on a chromosome from which the other alpha-globin gene has been deleted. The -alpha 3.7 deletion has resulted from crossing-over within segment I of the Z region of homology. There appears to be an unusually high proportion of the variant haemoglobin in heterozygotes which cannot be explained by gene dosage alone.

Chromosome Deletion↗
PubMed1986

A new epsilon globin HincII variant fragment length in a South African Negroid family.

A new HincII epsilon globin variant is reported in a South African Negroid family. The usual HincII epsilon globin fragment lengths are 8.0 and 3.7 kb and the variant described here is 14.0 kb in length. The 14.0 kb fragment was generated by a site alteration removing the 3' HincII site on a chromosome that already lacked the 5' HincII site. It appears that there are differences among races with regard to the frequencies of the 8.0 and 3.7 kb alleles. The 3.7 kb allele is the more common form in Caucasoids whereas the 8.0 kb allele occurs in the majority of Negroid and Khoisan subjects.

Black People↗
PubMed1986

Early physical therapy effects on the high-risk infant: a randomized controlled trial.

A prospective, randomized, controlled trial was conducted to assess the effects of early physical therapy on infants at risk for neurologic sequelae and to evaluate the impact of such early treatment on the prevention or minimization of future handicaps. A cohort of 134 infants who had received care in two Montreal inborn neonatal intensive care units was identified prospectively. Infants were stratified according to prognosis and birth weight and were randomly assigned to either an experimental or control group. Babies assigned to the experimental group received early physical therapy, whereas those allocated to the control group received conventional follow-up care. Outcome measures were administered by independent evaluators at 12 months and included measures of neurologic status, motor and overall development, and physical growth. No statistically significant differences on any of the measured outcomes at 12 months were found between the experimental and control groups. Infants weighing less than 750 g at birth, regardless of group assignment, consistently demonstrated significant delays in their growth and development when compared with their heavier peers. The early physical therapy program investigated in this study was not efficacious in altering the pattern of motor development in those high-risk infants participating in the trial.

Analysis of Variance↗
PubMed1985

Chorionic villus sampling for first trimester diagnosis of beta-thalassaemia. Report of the first South African case.

The first South African report of chorionic villus sampling for molecular diagnosis of beta-thalassaemia in a 10-weeks' pregnant Indian Muslim woman is presented. The sampling procedure and molecular techniques for sexing the fetus and establishing whether it was affected by beta-thalassaemia are described. From the sample of villi obtained a male fetus was identified, using an X-Y-specific DNA probe. A preliminary family study on both parents, the affected proband and his 4 phenotypically normal siblings, revealed two informative restriction fragment length polymorphisms in the mother, but none in the father. It was therefore not possible to differentiate between the two beta-globin gene alleles of the father. The fetus thus had a 50% chance of being a heterozygote or a 50% risk of being affected. Synthetic oligonucleotide hybridization of parental and fetal DNA was attempted by the Genetics Unit of Johns Hopkins Hospital, Baltimore, but the fetal hybridization was unsuccessful. Results on the parents were obtained too late to be of assistance in the present pregnancy as the parents requested termination of the pregnancy before 16 weeks' gestation for religious reasons.

Chorionic Villi↗