Third trimester placental grading by ultrasonography as a test of fetal wellbeing.

In a study of 2000 unselected pregnant women the development of a mature placental appearance (grade 3) on ultrasonography by 34-36 weeks'' gestation, observed in 15% of cases, was associated with maternal smoking, low parity, low maternal age, and being white. These women had an increased risk of problems during labour and their babies had an increased risk of low birth weight, poor condition at birth, and perinatal death. The women were randomly allocated to two groups: in one group the result of the placental grading was reported to the clinician responsible for care; in the second the result was noted but not reported. There was a significant decrease in the risk of perinatal death in the group where the grading was known. This reduction was responsible for a difference in the principal outcome index, a heterogeneous group of measures of mortality and morbidity, but this difference was not significant. This study alone does not justify routine late scanning, and further, larger trials are required. Nevertheless, the results do provide a basis for the reporting of placental grading when ultrasound examination is performed during the third trimester.     

Tests of the accuracy of cladograms in Gilia (Polemoniaceae) and some other angiosperm genera

 This paper deals with the use of cladistic methods and cladograms in phylogeny reconstruction in plant groups containing numerous taxa. How accurate are the cladograms as to details? Accuracy tests at the level of details require an independently known phylogeny, which excludes most plant groups, but such tests can be carried out in domesticated and experimental plant groups which have documented pedigrees. Four such tests are known and are presented here: a new case in Gilia and three previously published cases in Avena, Hordeum, and Helianthus. The four cases include domesticated and experimental plants, use of morphological and molecular evidence, and presence of dichotomous as well as reticulate phylogenies. The cladograms of the four plant groups all differ in significant details from the known pedigrees. These results are discussed in relation to problems of interpretation of cladograms. Received March 21, 2000 Accepted August 16, 2001     

Phylogenetic revision of Agapophytinae subf.n. (Diptera: Therevidae) based on molecular and morphological evidence

Agapophytinae subf.n. is a highly diverse lineage of Australasian Therevidae, comprising eight described and two new genera: Agapophytus Guérin‐Méneville, Acupalpa Kröber, Acraspisa Kröber, Belonalys Kröber, Bonjeania Irwin & Lyneborg, Parapsilocephala Kröber, Acatopygia Kröber, Laxotela Winterton & Irwin, Pipinnipons gen.n. and Patanothrix gen.n. A genus‐level cladistic analysis of the subfamily was undertaken using sixty‐eight adult morphological characters and c. 1000 base pairs of the elongation factor‐1α (EF‐1α) protein coding gene. The morphological data partition produced three most parsimonious cladograms, whereas the molecular data partition gave a single most parsimonious cladogram, which did not match any of the cladograms found in the morphological analysis. The level of congruence between the data partitions was determined using the partition homogeneity test (HT_F) and Wilcoxon signed ranks test. Despite being significantly incongruent in at least one of the incongruence tests, the partitions were combined in a simultaneous analysis. The combined data yielded a single cladogram that was better supported than that of the individual partitions analysed separately. The relative contributions of the data partitions to support for individual nodes on the combined cladogram were investigated using Partitioned Bremer Support. The level of support for many nodes on the combined cladogram was non‐additive and often greater than the sum of support for the respective nodes on individual partitions. This synergistic interaction between incongruent data partitions indicates a common phylogenetic signal in both partitions. It also suggests that criteria for partition combination based solely on incongruence may be misleading. The phylogenetic relationships of the genera are discussed using the combined data. A key to genera of Agapophytinae is presented, with genera diagnosed and figured. Two new genera are described: Patanothrix with a new species (Pat. skevingtoni) and Pat. wilsoni (Mann) transferred from Parapsilocephala, and Pipinnipons with a new species (Pip. kroeberi). Pipinnipons fascipennis (Kröber) is transferred from Squamopygia Kröber and Pip. imitans (Mann) is transferred from Agapophytus. Agapophytus bicolor (Kröber) is transferred from Parapsilocephala. Agapophytus varipennis Mann is synonymised with Aga. queenslandi Kröber and Aga. flavicornis Mann is synonymised with Aga. pallidicornis (Kröber).     

Mutant alpha-synuclein-induced degeneration is reduced by parkin in a fly model of Parkinson's disease.

Parkinson's disease (PD) patients show a characteristic loss of motor control caused by the degeneration of dopaminergic neurons. Mutations in the genes that encode alpha-synuclein and parkin have been linked to inherited forms of this disease. The parkin protein functions as a ubiquitin ligase that targets proteins for degradation. Expression of isoforms of human alpha-synuclein in the Drosophila melanogaster nervous system forms the basis of an excellent genetic model that recapitulates phenotypic and behavioural features of PD. Using this model, we analysed the effect of parkin co-expression on the climbing ability of aging flies, their life span, and their retinal degeneration. We have determined that co-expression of parkin can suppress phenotypes caused by expression of mutant alpha-synuclein. In the developing eye, parkin reduces retinal degeneration. When co-expressed in the dopaminergic neurons, the ability to climb is extended over time. If conserved in humans, we suggest that upregulation of parkin may prove a method of suppression for PD induced by mutant forms of alpha-synuclein.     

Direct Comparisons of 2D and 3D Dental Microwear Proxies in Extant Herbivorous and Carnivorous Mammals

The analysis of dental microwear is commonly used by paleontologists and anthropologists to clarify the diets of extinct species, including herbivorous and carnivorous mammals. Currently, there are numerous methods employed to quantify dental microwear, varying in the types of microscopes used, magnifications, and the characterization of wear in both two dimensions and three dimensions. Results from dental microwear studies utilizing different methods are not directly comparable and human quantification of wear features (e.g., pits and scratches) introduces interobserver error, with higher error being produced by less experienced individuals. Dental microwear texture analysis (DMTA), which analyzes microwear features in three dimensions, alleviates some of the problems surrounding two-dimensional microwear methods by reducing observer bias. Here, we assess the accuracy and comparability within and between 2D and 3D dental microwear analyses in herbivorous and carnivorous mammals at the same magnification. Specifically, we compare observer-generated 2D microwear data from photosimulations of the identical scanned areas of DMTA in extant African bovids and carnivorans using a scanning white light confocal microscope at 100x magnification. Using this magnification, dental microwear features quantified in 2D were able to separate grazing and frugivorous bovids using scratch frequency; however, DMTA variables were better able to discriminate between disparate dietary niches in both carnivorous and herbivorous mammals. Further, results demonstrate significant interobserver differences in 2D microwear data, with the microwear index remaining the least variable between experienced observers, consistent with prior research. Overall, our results highlight the importance of reducing observer error and analyzing dental microwear in three dimensions in order to consistently interpret diets accurately.     

Calculation of effective diffusivities for biofilms and tissues.

In this study we describe a scheme for numerically calculating the effective diffusivity of cellular systems such as biofilms and tissues. This work extends previous studies in which we developed the macroscale representations of the transport equations for cellular systems based on the subcellular-scale transport and reaction processes. A finite-difference model is used to predict the effective diffusivity of a cellular system on the basis of the subcellular-scale geometry and transport parameters. The effective diffusivity is predicted for a complex three-dimensional structure that is based on laboratory observations of a biofilm, and these numerical predictions are compared with predictions from a simple analytical solution and with experimental data. Our results indicate that, under many practical circumstances, the simple analytical solution can be used to provide reasonable estimates of the effective diffusivity.