Vascularized full-thickness parietal bone grafts in maxillofacial reconstruction: the role of the galea and superficial temporal vessels

Reconstruction of bony structures of the face is always a problem as big as the defect and the function that must be replaced. Everything from simple grafts to sophisticated distant bone flaps has been used. Based on the studies of Cutting et al., Psillakis et al., and Casanova et al., we have developed the full-thickness galeoparietal bone flap, initially for mandibular reconstruction, but of great use for all maxillofacial reconstructions. From July of 1987 to December of 1988, 14 patients have been operated on. The experience with this flap is shown in four patients as follows: primary reconstruction of a mandible as a result of ameloblastoma, secondary reconstruction of a mandible with associated old fractures and malalignment of segments, bilateral malar reconstruction in a patient with Treacher Collins syndrome, and severe sequelae of an already treated Romberg case. Small variations could be made to best accommodate the technique used to the defect we were treating. Some technical details, the experience, the results, and possible sequelae or complications are also discussed.     

Efficient Pre-mRNA Cleavage Prevents Replication-Stress-Associated Genome Instability

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The phylogenetic analysis of variable-length sequence data: elongation factor-1alpha introns in European populations of the parasitoid wasp genus Pauesia (Hymenoptera: Braconidae: Aphidiinae)

Elongation factor-1alpha (EF-1alpha) is a highly conserved nuclear coding gene that can be used to investigate recent divergences due to the presence of rapidly evolving introns. However, a universal feature of intron sequences is that even closely related species exhibit insertion and deletion events, which cause variation in the lengths of the sequences. Indels are frequently rich in evolutionary information, but most investigators ignore sites that fall within these variable regions, largely because the analytical tools and theory are not well developed. We examined this problem in the taxonomically problematic parasitoid wasp genus Pauesia (Hymenoptera: Braconidae: Aphidiinae) using congruence as a criterion for assessing a range of methods for aligning such variable-length EF-1alpha intron sequences. These methods included distance- and parsimony-based multiple-alignment programs (CLUSTAL W and MALIGN), direct optimization (POY), and two "by eye" alignment strategies. Furthermore, with one method (CLUSTAL W) we explored in detail the robustness of results to changes in the gap cost parameters. Phenetic-based alignments ("by eye" and CLUSTAL W) appeared, under our criterion, to perform as well as more readily defensible, but computationally more demanding, methods. In general, all of our alignment and tree-building strategies recovered the same basic topological structure, which means that an underlying phylogenetic signal remained regardless of the strategy chosen. However, several relationships between clades were sensitive both to alignment and to tree-building protocol. Further alignments, considering only sequences belonging to the same group, allowed us to infer a range of phylogenetic relationships that were highly robust to tree-building protocol. By comparing these topologies with those obtained by varying the CLUSTAL parameters, we generated the distribution area of congruence and taxonomic compatibility. Finally, we present the first robust estimate of the European Pauesia phylogeny by using two EF-1alpha introns and 38 taxa (plus 3 outgroups). This estimate conflicts markedly with the traditional subgeneric classification. We recommend that this classification be abandoned, and we propose a series of monophyletic species groups.     

Accelerated evolution in bacterial endosymbionts of aphids.

When compared with free living bacteria, it is proposed that there are at least two endosymbiotic processes in aphids based on the A + T content as well as the increased evolutionary rate of the beta-subunit of the F-ATPase complex in different endosymbiotic bacteria. The first well established process corresponds to the integration of Buchnera aphidicola more than 150 million years ago. The other is postulated to correspond to new endosymbiotic processes in which the bacteria involved contain less A + T and show a lower increase of evolutionary rates when compared with B. aphidicola. It is proposed, therefore, that endosymbioses are active processes in aphid evolution.     

Effects of group size and personality on social foraging: the distribution of sheep across patches

Group cohesion in social animals foraging in patchy environmentsdepends on 2 opposite forces, intraspecific competition, andattraction. The decision to leave or stay in a group may varyaccording to the individual personality. We investigated therole of personality when feeding competition increases as aresult of increasing group size. Individuals referred as "bold"and "shy" were identified from an indoor exploration test accordingto their propensity to leave the group to explore a novel environment,using 12 novel objects placed at increasing distances from thegroup. Groups of 2, 4, 6, or 8 shy or bold sheep were testedin 45 x 5–m grass arenas, with one 5 x 5–m patchof preferred vegetation at each end. Sheep grazed on or closeto these patches, but the number grazing the patches seldomreached more than 4–5 individuals, suggesting that crowdingmight affect foraging at the highest densities. The smallestgroups grazed together on the same patch, but there was an increasinglikelihood of splitting into subgroups as group size increased,with equal-sized subgroups most commonly grazing the 2 patchessimultaneously. This effect was greatest in bold sheep, whichtended to split into subgroups at smaller group sizes than shysheep. This study provides new insight into the mechanisms bywhich group-living herbivores distribute themselves across patchyresources in a way that minimizes interference competition anddemonstrates the importance of individual variability for spatialorganization at the level of the group.     

High-carotenoid maize: development of plant biotechnology prototypes for human and animal health and nutrition

Carolight^® is a transgenic maize variety that accumulates extraordinary levels of carotenoids, including those with vitamin A activity. The development of Carolight^® maize involved the technical implementation of a novel combinatorial transformation method, followed by rigorous testing for transgene expression and the accumulation of different carotenoid molecules. Carolight^® was envisaged as a way to improve the nutritional health of human populations that cannot access a diverse diet, but this ultimate humanitarian application can only be achieved after extensive testing for safety, agronomic performance and nutritional sufficiency. In this article, we chart the history of Carolight^® maize focusing on its development, extensive field testing for agronomic performance and resistance to pests and pathogens, and feeding trials to analyze its impact on farm animals (and their meat/dairy products) as well as animal models of human diseases. We also describe more advanced versions of Carolight^® endowed with pest-resistance traits, and other carotenoid-enhanced maize varieties originating from the same series of initial transformation experiments. Finally we discuss the further steps required before Carolight^® can fulfil its humanitarian objectives, including the intellectual property and regulatory constraints that lie in its path.     

Complete turgor maintenance at low water potentials in the elongating region of maize leaves

Leaf elongation rate, water potential, and osmotic potential were measured in the fifth leaf of maize (Zea mays L.) plants growing in soil from which water was withheld for varying times. Elongation occurred in the basal region, which was enclosed by other leaf sheaths. When water was withheld from the soil, leaf elongation decreased and eventually ceased even though enough solutes accumulated in the elongating region to maintain turgor virtually constant. In the exposed blade, however, turgor was lost and wilt symptoms developed. If the night was prolonged, the elongating region lost much of its ability to accumulate solute, which suggests that the accumulating solutes were of recent photosynthetic origin. Under these conditions, leaf elongation was restricted to higher water potentials than under the usual photoperiodic regime.     

Sexual dimorphism, activity budget and synchrony in groups of sheep

The activity budget hypothesis has been proposed to explain the social segregation commonly observed in ungulate populations. This hypothesis suggests that differences in body size – i.e. between dimorphic males and females – may account for differences in activity budget. In particular, if females spend more time grazing and less time resting than males, activity synchrony would be reduced. Increased costs of maintaining synchrony despite differences in activity budget would facilitate group fragmentation and instability of mixed-sex groups. In this paper two prerequisites of the activity budget hypothesis were tested: (1) that males should spend less time feeding and more time resting than females in single-sex groups and (2) that lower activity synchrony should be observed in mixed-sex compared to single-sex groups. The activity budget and synchrony in mixed and single-sex groups of merino sheep (Ovis aries) of different sizes (2, 4, 6, 8 individuals) were measured in three contiguous 491-m² arenas located in a natural pasture. Three same-size groups, one of each category, were observed simultaneously. We found no sexual differences in the time spent inactive and active (i.e. grazing, standing, moving, interacting). Males spent significantly more time grazing and less time standing than females. These differences disappeared when yearling males were omitted from the group. Males and females had similar bite and step rates. Sheep of both sexes spent less time resting and more time grazing and moving and had lower bite rates when in mixed-sex groups than when in single-sex groups. The synchrony among visually isolated groups was near zero, indicating that they changed activities independently. On the contrary, within-group synchrony was high; however it was higher in single-sex groups, in particular for males, than in mixed-sex groups. Our results suggest that differences in activity budget and synchrony alone are insufficient to explain social segregation.     

Palynological analysis of Cheilanthes Species (Adiantaceae-Pteridophyta) of Northwestern Argentina

The spores of seven Cheilanthes Sw. species that grow in the Northwest Region of Argentina were studied with LM, SEM and TEM.

They were: Cheilanthes margínala H. B. K., C. micropteris Sw., C. myriophylla Desv., C. notholaenoides (Desv.) Weath., C. pilosa Gold., C. poeppigiana Mett. ex Kuhn, and C. pruinata Kaulf.

C. volcanensis de la Sota, mentioned for the region, was not included because all the collected material was sterile or immature.

The equatorial diameter is not useful in distinguishing species because of the interspecific variability of such species as C. micropteris, C. poeppigiana and C. pruinata. In other cases interspecific variation overlaps.

All the species analysed here have one basic pattern of structure: a homogeneous, smooth exospore and a sculptured perispore.

The perispore has two layers: an innermost one, granular, compact and an outermost one, reticulate with or without an outer lamella. The outermost layer constitutes the greatest part of the perispore.

Five sculpture groups were distinguished: rugulose, ridged, cristate, cristate-reticulate and tridimensionally reticulate.

One new type of sculpture is mentioned in Cheilanthes: ridged.