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Biomedical subjects

J E Bowman

Publications and source records attributed to J E Bowman.

At least 19 recordsLinked to original sources
PubMed1995

Growth and threshold weaning weights among captive rhesus macaques.

Interspecific analyses of infant growth and the time to maternal reconception (or weaning) demonstrate a consistent threshold for weaning weight at close to four times neonate weight, irrespective of the duration of lactation (Lee et al., [1991] J. Zool. Lond. 225:99-114). Intraspecific variation in the attainment of a threshold weaning weight was determined in a sample of 31 captive infant rhesus macaques, where growth between birth and subsequent parturition was measured along with information on maternal size, weight, and social characteristics. A threshold weaning weight was found, with infants attaining approximately 1,335 g at the time of reconception. Birth weights of the infants were influenced by maternal physical and social variables in that larger mothers, and alpha ranking mothers, produced larger neonates. Postnatal growth rate, which determined the attainment of the threshold weight, was independent of maternal size or condition, but was influenced by offspring sex and the probability of reconception. Future reproductive status of mothers was specifically related to differences in patterns of growth among the infants. Mothers who conceived again at 30 weeks had infants who grew more slowly after the first 12 weeks of life, especially if these infants were sons. Mothers in this colony appeared to make decisions about the need to sustain their infants' growth in relation to their ability to invest in current offspring, which may compromise their subsequent reproduction.

Animals↗
PubMed1995

Age determination from dental microstructure in juveniles.

The crypts outside St Bride's Church, London, contain a documented collection of skeletal remains dating from the mid-18th century. Some of these remains became mixed during post-war restoration work on the church. The worst example of such mixing involves ten infants that were boxed all together with their corresponding coffin plates. All the infants were aged between 1 and 4 years at death. Recognized skeletal aging criteria proved unsuccessful in identifying the bodies. A more precise method of age estimation was utilized in order to separate these individuals. Age was determined using the incremental markers found in dental microstructure which are thought to be formed in circadian and circaseptan rhythms. The resulting age estimates were compared with the real ages obtained from the coffin plates and death certificates. Confident identification was achieved in eight out of ten cases. This study illustrates the potential value of a little-known aging method in circumstances where commonly used methods have proved unsuccessful.

Age Determination by Teeth↗
PubMed1986

HB Chicago or alpha (2)136 (H19) Leu----Met beta 2 and a -G gamma-G gamma-globin gene arrangement in a black family.

Hb Chicago is a newly discovered hemoglobin variant which was present in a Black newborn baby and her father. The leucine residue at alpha 136, which normally participates in the contact with the heme group, is replaced by a methionine residue. The two heterozygotes were clinically well with normal hematological data. Isolation of the alpha X and alpha A chains by reverse phase high performance liquid chromatography and hydrolysis of these chains with dilute formic acid at 110 degrees C for 24 hours, followed by separation of the resulting peptides by reverse phase high performance liquid chromatography, greatly facilitated the final identification of the abnormality. The baby and both parents had a -G gamma-G gamma-globin gene arrangement on one chromosome (normal: -G gamma-A gamma-) which explains the high G gamma values in the Hb F of these three persons.

Amino Acid Sequence↗
PubMed1983

Is a national program to prevent sickle cell disease possible?

There is no specific therapy for sickle cell disease, and there is no evidence that sickle hemoglobin screening by conventional methods will lead to a significant reduction in the number of children with sickle cell disease. Thus it follows that if there is to be a national program to prevent sickle cell disease, the only recourse is one based on prenatal diagnosis and selective abortion of affected embryos or fetuses. Present-day dire poverty and callous health care public policies lead to the inescapable conclusion that a concerted attempt to alleviate poverty and its consequent adverse effects on maternal, neonatal, and infant mortality should take precedence over, or at the least coincide with, a national program to prevent sickle cell disease. On the other hand, it is argued that a woman should have the right to decide whether or not she wishes to have a child with a genetic disorder, and that recent advances in research on prenatal diagnosis, particularly when supported by public funds, should be made available to all, and not just the affluent.

Abortion, Induced↗
PubMed1980

Genetic variation in Cameroon: thermostability variants of hemoglobin and of glucose-6-phosphate dehydrogenase.

The technique of heat denaturation was used in addition to electrophoresis for the detection of thermostability variants of hemoglobin and glucose-6-phosphate dehydrogenase in an attempt to measure the amount of genetic variability present in villages in the United Republic of Cameroon, Equatorial Africa. A minimum of three to a maximum of 13 thermostability variants were estimated for HbA and HbS, and a minimum of two to a maximum of ten thermostability variants were estimated for GdA, GdB, and GdA-. It is suggested that hemoglobin and glucose-6-phosphate dehydrogenase thermostability variants are genetically determined and that the sites of these variants are at the hemoglobin and glucose-6-phosphate dehydrogenase structural loci. The evidence for the existence of these hidden variants and their importance in the neutralist v. selectionist controversy are discussed.

Cameroon↗
PubMed1980

Interaction of sickle cell trait and glucose-6-phosphate dehydrogenase deficiency in Cameroon.

The prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency and sickle cell trait was determined in 371 Cameroonian males and 668 male blood donors in Chicago. The number of males with both sickle cell trait and G6PD deficiency was significantly greater than expected (p less than 0.05) in Cameroon. The number of males with both sickle cell trait and G6PD deficiency in the Chicago population also exceeded the exptected number, although this was not statistically significant (p greater than 0.30). A young red cell population associated with the sickle cell gene leading to elevated G6PD levels in G6PD-deficient males suggests that sickle hemoglobin may exert a beneficial effect on G6PD deficiency, rather than the opposite, as had previously been proposed. These red cells may be better able to deal with oxidative stress, which can precipitate severe hemolytic disease in G6PD deficiency.

Anemia, Sickle Cell↗
PubMed1980

Population studies in Cameroon: hemoglobin S, glucose-6-phosphate dehydrogenase deficiency and falciparum malaria.

Examination of blood samples from 1,183 individuals from Cameroon indicates that sickle cell trait frequencies and G6PD deficiency frequencies were heterogeneous among villages as well as within geographic areas and ethnic groups. Mean parasite counts were significantly correlated with Hb AS frequencies for children 6 years of age and under, although no correlation was found for mean parasite counts and G6PD deficiency frequencies. The mean age of sickle cell trait individuals was found to be significantly greater than the mean age of Hb AA individuals. The mean age of G6PD-deficient males did not differ from the mean age of G6PD-normal males. Hb AA and Hb AS children did not differ significantly in mean positive parasite counts. Falciparum malaria appears to be a selective pressure keeping Hb S frequencies high; yet it may not be the major selective force maintaining the G6PD polymorphism.

Age Factors↗
PubMed1977

Hemoglobin and the genetic code. Evolution of protection against somatic mutation.

One-half of the twenty amino acids of the genetic code are just one mutational step away from the chain-terminator codons UAA, UAG, and UGA. It is postulated that somatic mutation to terminator is a hazard to which the organism has and to respond by adjusting certain proteins in the direction of fewer mutable residues. This view is supported by calculations based on the primary structure of five of the human hemoglobin chains. Each chain is scored for mutability to terminator in accord with the numbers and kinds of amino acids present. Among the adult chains, the most essential one, the alpha, has lowest mutability. The beta and delta follow, and in order of the presumed harm to the organism of a shortage of chain copies. Ante-natal chains tend to have higher mutabilities, supporting the view that cumulative mutational change in DNA can do little if the gene ceases to transcribe early in life. Two other predicitons based on the supposition of effective selection against mutability to terminator are also met: chain length of polypeptides is negatively correlated with their scores for mutability to terminator, and examination of the recently determined sequence of beta messenger RNA shows preferential use of codons that are not readily mutable to terminator.

Amino Acid Sequence↗
PubMed1977

Modification of the acid elution technique for quantitation of fetal hemoglobin in individual erythrocytes.

A modification of the acid elution procedure for the demonstration of fetal hemoglobin in red cells using fast green stain is described. This technique not only permits improved visual estimation of the amount of fetal hemoglobin in red cells, but allows for the direct quantitation of fetal hemoglobin content of individual cells, using a scanning and integrating microdensitometer. As an application of this method, the distribution of fetal hemoglobin in populations of red cells of individuals was determined. Distributions were examined in sickle cell anemia patients with different proportions of fetal hemoglobin.

Anemia, Sickle Cell↗
PubMed1976

The demonstration of asymmetric hemoglobin hybrids by polyacrylamide electrophoresis.

A simpler, more economical technique than previously reported, that of conventional polyacrylamide gel electrophoresis alone, is described for the detection of asymmetric hemoglobin hybrids of the forms alphaXalphaYbeta2 and alpha2betaXbetaY when bloods from individuals with alpha and beta chain variants were examined. The presence of alpha chain variant hybrids, never before reported, is further evidence that hybrid formation is a more widespread phenomenon than has previously been thought of. Hybrids were found in artificial mixtures of hemoglobins and more importantly, are also reported here for the first time in bloods of individuals heterozygous for hemoglobin variants. These hybrid tetramers were as stable as the parent hemoglobins when examined under anaerobic conditions. The involvement of HbF in the formation of hybrids of the type alpha2betagamma is reported, and an analysis of the possible role of these as well as alpha2betaAbetaS hybrids in the sickling process is presented.

Binding Sites↗