Conceiving a fetus for bone marrow donation: An ethical problem in prenatal diagnosis

We present a family who sought prenatal diagnosis in order to bear a healthy child to serve as an HLA–identical bone marrow donor for their son affected with Wiskott–Aldrich syndrome. They intended to abort HLA-incompatible fetuses who would have been unsuitable bone marrow donors. This case led us to conclude that prenatal diagnosis should not be used to benefit a third party or facilitate the conception or abortion of a fetus for the purpose of generating an organ for transplantation. The limits of parental autonomy and physician responsibility are discussed.     

Comparative study of genetic and social structure in two forms of the fire ant Solenopsis invicta (Hymenoptera: Formicidae)

Summary The genetic and social structures of polygyne and monogyne forms of the fire ant, Solenopsis invicta, are investigated in a comparative manner using allozyme data from two polymorphic loci. Foundress queens of the monogyne form are signly inseminated and appear to produce all males present in the colony during the major summer mating flights. The average regression coefficient of relatedness (b) among female nestmates of the monogyne form is 0.714 (Fig. 2), statistically indistinguishable from the pedigree coefficient of relatedness (G) of 0.75. We suggest that the evolution of obligate worker sterility in Solenopsis is associated with this high relatedness between workers and the queens they rear. Functional queens in polygyne nests also are singly inseminated and are no more closely related to nestmate queens than to other queens (within-nest b=0). Within-nest relatedness of workers in the polygyne population is similarly low (Fig. 2). Both the monogyne and polygyne populations from northcentral Georgia are in Hardy-Weinberg equilibrium at both allozyme loci and we found no evidence of significant population subdividion or inbreeding in the polygyne population. These results do not support the view that kin selection has promoted the evolution of polygyny in North American S. invicta. Rather, mutualism appears to be the most likely selective factor mediating queen associations inthis ant.     

Vibrational signals in a gregarious sawfly larva (<Emphasis Type="Italic">Perga affinis</Emphasis>): group coordination or competitive signaling?

Group living confers both benefits and costs to the individuals involved. Benefits may include enhanced defense, thermoregulation, and increased foraging efficiency while costs often involve competition for resources such as food, shelter, and mates. Communication provides a medium of exchange among individuals engaged in either cooperative or competitive interactions. The functional analysis of signals within groups therefore requires testing both cooperative and competitive functions, although the latter is infrequently done. In this paper, I study the use of two vibrational signals in a gregarious, processionary Australian sawfly larva, Perga affinis: tapping and contractions. Tapping involves striking the substrate with the sclerotized portion of the abdominal tail and a contraction is a fast, whole-body twitch, which is both tactile and vibrational in its transmission. For tapping, I first demonstrate that it is a form of communication, as tapping of one larva elicits tapping in another, and that it is transmitted through substrate vibrations. I then test whether the signal is mostly cooperative or competitive in nature by examining it in light of two hypotheses: (1) the Group Coordination hypothesis, stating that the signal functions to maintain group cohesiveness and (2) the Competitive Signaling hypothesis, stating that tapping serves as a competitive assessment signal between larvae while feeding. For contractions, I test only the group coordination hypothesis that they serve to coordinate and initiate group movement. Results support the group coordination hypothesis for each signal. While feeding, lone larvae (without potential competitors) were significantly more likely to tap than those in groups, and this trend continued in non-feeding situations. Contractions regularly preceded periods of group movement during processions and were given with increasing frequency before departure from preforaging clusters. The vibrational signals in this processionary species likely function cooperatively to maintain group cohesiveness and coordinate movement.     

Growth rate of larval Sardinops sagax from ecosystems with different levels of productivity

Otolith increment data were used to age larval Sardinops sagax from shelf waters between 118°E and 137°E off southern Australia. Maximum and mean growth rates up to an age of 30 days, estimated from a Laird-Gompertz model, were 0.62 and 0.48 mm day^-1, respectively. The growth rate of larval S. sagax from southern Australia was less than, or at most comparable to, those estimated from the substantially more productive upwelling systems of southwestern Africa, the central coasts of North and South America, and inshore of the Kuroshio system east of Japan. The lower productivity of the sardine habitat off southern Australia could be expected to manifest as fewer and/or less extensive patches of suitably dense plankton, or lower levels of sufficient food availability, which results in the lower growth rate of larvae. This probably causes higher mortality and, along with slower growth rates of post-recruit stages, may therefore contribute to the low stock size of sardines in southern Australia. Nonetheless, the similarities in growth rates of larvae within a single species over widely separated regions suggest such rates fall between predetermined bounds, limited by starvation at the lower end and an ontogenetic maximum at the other.     

Update on selective reduction

Over the past 25 years fetal reduction has been utilized to reduce the risks of higher-order multiple pregnancies that have resulted from overly successful infertility therapies. The demographics of multiple pregnancy patients have evolved over the past decade, with increasing proportions coming from IVF as opposed to ovulation induction, being older and a higher proportion with donor eggs. Genetic diagnosis prior to reduction is becoming more common and is very safe in experienced hands. For all starting numbers, including twins, reduction to a lower number of fetuses reduces fetal losses, prematurity, and infant mortality and morbidity. Copyright © 2005 John Wiley & Sons, Ltd.     

The impact of multiple source feedback on management development: findings from a longitudinal study

Despite the rapid uptake of multi‐source multi‐rater (MSMR) feedback systems by UK organizations, comparatively little research exists describing the actual impact on participant managers, in terms of changes in management competence. Ratings of 104 target managers (by self assessments, bosses‐, first‐ and second‐level subordinates) were investigated within the context of a developmental feedback programme in operation within an organization. The study compared ratings over two administrations (with two years between administrations) to determine: (1) changes in co‐workers' perceptions of their target manager's competence, (2) changes in target managers' development needs over time, (3) factors influencing a target manager's revised self‐assessment and co‐workers ratings, (4) changes in congruence between self and co‐workers ratings and (5) the relationship of feedback to the organization's formal performance appraisal process. Significant increases in managers' competence were perceived by the managers' themselves and by their subordinates, development needs were seen to reduce and self and co‐workers ratings were largely seen to become more congruent. However, polynomial regression analyses revealed co‐workers feedback at Time One was not predictive of targets' self‐assessments at Time Two. The implications of these findings with regard to the utility of MSMR feedback as a tool for management development are discussed. Copyright © 2002 John Wiley & Sons, Ltd.