Growth in length of infants in Khartoum is profoundly related to whether or not their mothers are in paid employment. Some of this relationship appears to be due to levels of infectious disease, which are much higher in the infants of working mothers. Exponential decay curves do not fit longitudinal measurements of length growth particularly well in either group of infants, but they do yield distinctive temporal patterns of residuals. Simulation demonstrates that these patterns accord with a "catch-down" form of growth in infants of working mothers and a "catch-up" form in infants of housewives. Attempts to allow for these phenomena by providing for the opportunity of a single pulse of negative sine form in the former and a similar pulse of positive sine form in the latter reduces the level of residuals and tends to reduce temporal pattern in them. Most strikingly, it leads to average growth curves for the two groups of children becoming almost identical. It is hypothesized that these decay curves represent the underlying curves of infant growth in Khartoum free from the effects of environmental variation.

Environment↗

PubMedDate not supplied

Further characterization of T cell receptor chains of marsupials.

cDNA clones encoding T cell receptor alpha (TCRalpha) and beta (TCRbeta) from the South American opossum, Monodelphis domestica were isolated and characterized. A single clone isolated encoding a TCRalpha chain was full length, containing the complete V (variable), J (joining) and C (constant) regions. Three partial cDNA clones were isolated for TCRbeta which contained complete C sequences. Phylogenetic analysis of the TCR Valpha revealed that the M. domestica sequence and a sequence from the Australian brushtail possum, Trichosurus vulpecula, belong to separate Valpha families and intersperse with sequences from eutherian mammals. Similar to results described for marsupial and eutherian light chains, diversity at the V region of the TCR is ancient and maintained. In contrast phylogenetic analysis of the TCR Calpha and Cbeta sequences from M. domestica, T. vulpecula, and other vertebrates revealed that the marsupial TCR C grouped together forming a sister group to eutherian mammals.

Amino Acid Sequence↗