bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic consequences of an introduction-colonization process in an endangered butterfly species
Authors: Barascud  , Martin  , Baguette  , Descimon
Published: March 2003

From a theoretical point of view, the genetic consequences of foundation events are relatively well known but few field experimental data are available on this subject. At the beginning of the 1970s, a small number of Proclossiana eunomia females were released in a region where this glacial relict was absent. We report here the genetic aspects of the evolution of the populations generated by these translocations. Both enzyme electrophoresis and wing pattern morphometry disclosed a significant differentiation of the populations both with their mother population and within themselves. Field observations and enzyme data suggest a stepping-stone colonization process, but there is no significant isolation by distance at this stage of population establishment, as predicted by Slatkin’s 1993 model. Concerning phenotypic characters, there is a significant correlation between morphometric and geographical distances; this may be due to isolation by distance but the action of environmental gradients cannot be excluded. Our results show that this colonization, although induced with a low number of founders, was a success, despite a predicted loss of polymorphism.
The influence of parthenogenesis-inducing Wolbachia on the oviposition behaviour and sex-specific developmental requirements of autoparasitoid wasps
Authors: Hunter
Published: March 2003

Parthenogenesis-inducing (PI) Wolbachia are bacteria that cause incipient male eggs of parasitoid wasps to develop as females. These microbes may invade populations and lead to fixation of parthenogenesis. In this study, the consequences of fixation of PI Wolbachia on evolution of behaviour and development were addressed in three species of whitefly parasitoids in the genus Encarsia.

Most sexual Encarsia are obligate autoparasitoids. In these haplodiploid wasps, fertilized, female-producing eggs are laid in whitefly or scale insect nymphs, while unfertilized, male-producing eggs are laid in immature parasitoids within the homopteran integument. The oviposition behaviour and progeny developmental requirements of unmated females of a sexual autoparasitoid species were compared with two species that were fixed for PI Wolbachia. All species were treated with antibiotics, effectively ‘curing’ the asexual species of Wolbachia infection.

As expected, unmated females of the sexual species, E. pergandiella, laid few eggs in whiteflies relative to immature parasitoids, and males emerged exclusively from parasitoids. In contrast, females of one of the parthenogenetic species, E. formosa, laid few eggs in parasitoids relative to whiteflies, and male progeny emerged exclusively from whiteflies. Females of the second parthenogenetic species, E. hispida, were intermediate in their oviposition behaviour. Females laid eggs in both wasps and whiteflies. However, all of the males except one emerged from the whiteflies. The results suggest that the association of autoparasitoids and PI Wolbachia may result in dramatic evolutionary change of both host selection behaviour and developmental requirements of the infected wasps.
Locomotor impairment of gravid lizards: is the burden physical or physiological?
Authors: Olsson  , Shine  , Bak-Olsson
Published: March 2003

Pregnancy is associated with reduced locomotor performance in several reptile species, but the reasons for this reduction remain unclear. Previous authors generally have assumed that the decreased maternal mobility is due to the physical burden of the clutch, but our data on a viviparous Tasmanian scincid lizard (Niveoscincus microlepidotum) suggest a different interpretation. Running speeds of gravid female skinks decrease during gestation (as litter mass increases), but this locomotor impairment is due to physiological changes associated with pregnancy, rather than simple physical burdening. Maternal running speeds are unrelated to litter masses, and do not increase in the week after parturition. Females with very large abdominal fat-bodies (due to ad libitum feeding in the laboratory), equivalent in mass to the litter, nonetheless run rapidly. If the locomotor ‘costs’ of reproduction reflect all-or-none physiological changes associated with pregnancy, then the magnitude of such costs may correlate only weakly with the actual level of reproductive investment. Because life-history models predict that the relationship between fecundity and ‘cost’ has important evolutionary consequences, our results highlight the need to clarify the causal basis for locomotor impairment in gravid reptiles.
Trade-offs between growth and reproduction: an analysis of the quantitative genetic evidence
Authors: Roff
Published: March 2003

The assumption of a trade-off between development time and fecundity, resulting from a positive correlation between body size and fecundity and between body size and development time, is a common feature of life history models. The present paper examines the evidence for such a trade-off as indicated by genetic correlations between traits. The genetic covariances between traits are derived using a model in which maturation occurs when the organism achieves a genetically variable size threshold, and fecundity is an allometric function of body size with one genetically variable parameter (excluding body size itself). This model predicts that the heritabilities of the life history traits (growth rate, development time, fecundity) will not necessarily be less than the heritability of adult size (i.e. morphological traits). It is shown that if growth rate is genetically correlated with adult size then it is not possible, in general, to predict the sign of the genetic correlation between development time and fecundity. For particular cases the signs of the covariances between traits can be predicted. These predictions are tested using data drawn from the literature.
The balance between sexual and asexual reproduction in plants living in variable environments
Authors: Bengtsson  , Ceplitis
Published: March 2003

The balance between sexual and asexual propagule production is studied in an evolutionary model where plants produce the two kinds of propagules in genetically determined proportions. The male function of plants producing asexual propagules can be varied, and the sexual and asexual propagules carry different probabilities to turn into new reproductive individuals. These fitnesses may vary over years. The evolution of the population’s reproductive system is studied assuming modifier alleles with small effects.

In this setting a balanced, mixed reproductive system can evolve, but only if the difference in fitness between the sexual and asexual propagules varies over years. When the two kinds of propagules are very similar to each other, as is often the case with sexual and asexual seed formation, evolution will tend towards a state dominated by the one or the other reproductive system.
Phenotypic selection and response to selection in Lobularia maritima: importance of direct and correlational components of natural selection
Authors: GÓmez
Published: March 2003

By using selection differentials, gradients and structural equation modelling (SEM), I have quantified the phenotypic selection acting on Lobularia maritima (Cruciferae) flower size, display, colour and density, using data on lifetime female fitness. Furthermore, by analysing the resulting F1 generation in field and greenhouse conditions, I estimated the actual intergenerational change in the value of these traits. Both pollinators preferred plants with many and large flowers. Strong directional selection for increased flower display was found in all years of the study, regardless of the technique used. Indirect selection due to a high significant correlation with flower display occurred on flower colour and size. SEM showed that pollinators played only a minor role in this observed phenotypic selection. The analysis of the phenotypes of F1 plants showed that flower display actually increased across generations. In addition, white flowers were significantly more frequent in the offspring population than in the parental one, mostly due to the association between flower display and white coloured flowers. This suggests that both direct and indirect selection can play a role in the evolution of correlated traits in this crucifer.
Mating frequency and resource allocation to male and female function in the simultaneous hermaphrodite land snail Arianta arbustorum
Authors: Locher  , Baur
Published: March 2003

Sex allocation theory predicts that mating frequency and long-term sperm storage affect the relative allocation to male and female function in simultaneous hermaphrodites. We examined the effect of mating frequency on male and female reproductive output (number of sperm delivered and eggs deposited) and on the resources allocated to the male and female function (dry mass, nitrogen and carbon contents of spermatophores and eggs) in individuals of the simultaneous hermaphrodite land snail Arianta arbustorum. Similar numbers of sperm were delivered in successive copulations. Consequently, the total number of sperm transferred increased with increasing number of copulations. In contrast, the total number of eggs produced was not influenced by the number of copulations. Energy allocation to gamete production expressed as dry mass, nitrogen or carbon content was highly female-biased (>95% in all estimates). With increasing number of copulations the relative nitrogen allocation to the male function increased from 1.7% (one copulation) to 4.7% (three copulations), but the overall reproductive allocation remained highly female-biased. At the individual level, we did not find any trade-off between male and female reproductive function. In contrast, there was a significant positive correlation between the resources allocated to the male and female function. Snails that delivered many sperm also produced a large number of eggs. This finding contradicts current theory of sex allocation in simultaneous hermaphrodites.
Increased body size confers greater fitness at lower experimental temperature in male Drosophila melanogaster
Authors: Reeve  , Fowler  , Partridge
Published: March 2003

Genetic variation of body size along latitudinal clines is found globally in Drosophila melanogaster, with larger individuals encountered at higher latitudes. Temperature has been implicated as a selective agent for these clines, because the body size of laboratory populations allowed to evolve in culture at lower temperatures is larger. In this study, we investigated the hypothesis that larger size is favoured at lower temperature through natural selection on adult males. We measured life-span and age-specific fertility of males from lines of flies artificially selected for body size at two different experimental temperatures. There was an interaction between experimental temperature and body size selection for male fitness; large-line males were fitter than controls at both temperatures, but the difference in fitness was greater at the lower experimental temperature. Smaller males did not perform significantly differently from control males at either experimental temperature. The results imply that thermal selection for larger adult males is at least in part responsible for the evolution of larger body size at lower temperatures in this species. The responsible mechanisms require further investigation.
Epistatic interactions of spontaneous mutations in haploid strains of the yeast Saccharomyces cerevisiae
Authors: Wloch D. M. , Borts R. H. , Korona R.
Published: March 2003

Several important biological phenomena, including genetic recombination and sexual reproduction, could have evolved to counteract genome contamination by deleterious mutations. This postulate would be especially relevant if it were shown that deleterious mutations interact in such a way that their individual negative effects are reinforced by each other. The hypothesis of synergism can be tested experimentally by crossing organisms bearing deleterious mutations and comparing the fitness of the parents and their progeny. The present study used laboratory strains of the budding yeast burdened with mutations resulting from absence of a major DNA mismatch repair function. Only in one, or possibly two, crosses out of eight did fitness of the progeny deviate from that of their parents in a direction indicating synergism. Furthermore, the distributions of progeny fitness were not skewed as would be expected if strong interactions were present. The choice of experimental material ensured that genetic recombination was extensive, all four meiotic products were available for fitness assays, and that the mutations were probably numerous. Despite this generally favourable experimental setting, synergism did not appear to be a dominating force shaping fitness of yeast containing randomly generated mutations.
Wolbachia infection in crustaceans: novel hosts and potential routes for horizontal transmission
Authors: Cordaux R. , Michel-Salzat A. , Bouchon D.
Published: March 2003

Thirty-five percent of isopods are estimated to be infected by Wolbachia, an intracellular maternally inherited α-Proteobacterium. Previous studies have indicated that horizontal transfer of Wolbachia strains may occur, although the mechanisms are unclear. The wsp gene was sequenced from 17 Wolbachia strains harboured by crustacean host species and three from their associated predators and parasites. Two major clades of Wolbachia were found in crustacean, with relatives also found in insects, the other restricted to crustaceans. Highly divergent Wolbachia strains were found in a woodlouse-eating spider and its prey, suggesting no intertaxon bacterial exchange via the predator–prey route. The phylogenetic proximity of Wolbachia from parasitoid flies or phoretic mites to those from isopods suggests that horizontal symbiont transmission may have occurred between those taxa. Two distant Wolbachia strains were detected in two intertidal amphipods; these strains were closely related to different coastal isopod symbionts, suggesting Wolbachia transmission may occur between distantly related crustacean hosts living under the same ecological conditions.
The minor transitions in hierarchical evolution and the question of a directional bias
Authors: McShea D. W.
Published: March 2003

The history of life shows a clear trend in hierarchical organization, revealed by the successive emergence of organisms with ever greater numbers of levels of nestedness and greater development, or ‘individuation’, of the highest level. Various arguments have been offered which suggest that the trend is the result of a directional bias, or tendency, meaning that hierarchical increases are more probable than decreases among lineages, perhaps because hierarchical increases are favoured, on average, by natural selection. Further, what little evidence exists seems to point to a bias: some major increases are known – including the origin of the eukaryotic cell from prokaryotic cells and of animals, fungi and land plants from solitary eukaryotic cells – but no major decreases (except in parasitic and commensal organisms), at least at the cellular and multicellular levels. The fact of a trend, combined with the arguments and evidence, might make a bias seem beyond doubt, but here I argue that its existence is an open empirical question. Further, I show how testing is possible.
The evolution of polyandry: an examination of the genetic incompatibility and good-sperm hypotheses
Authors: Simmons L. W.
Published: March 2003

I have examined the adaptive significance of polyandry using the Australian field cricket Teleogryllus oceanicus. Previous studies of polyandry have examined differences in offspring production by females mated multiply to a single male or females mated multiply to different males. Here I combine this approach with a study of parentage of offspring produced in the later group. Females mated to two different males had a higher proportion of their eggs hatching than did females mating twice with a single male. Offspring fitness parameters were not effected. There was little evidence to suggest that females elevate their hatching success via fertilizing their eggs with sperm from genetically compatible males. Although the average paternity points towards random sperm mixing, there was considerable individual variation in sperm competition success. Patterns of parentage were consistent across females mating twice or four times. Sperm competition success was not related to offspring viability or performance. Thus, the notion that competitively superior sperm produce competitively superior offspring is not supported either. The mechanism underlying increased hatching success with polyandry requires further study.
Factors influencing paternity success in Antechinus agilis: last-male sperm precedence, timing of mating and genetic compatibility
Authors: Kraaijeveld-Smit F. J. L. , Ward S. J. , Temple-Smith P. D. , Paetkau D.
Published: March 2003

We describe the patterns of paternity success from laboratory mating experiments conducted in Antechinus agilis, a small size dimorphic carnivorous marsupial (males are larger than females). A previous study found last-male sperm precedence in this species, but they were unable to sample complete litters, and did not take male size and relatedness into account. We tested whether last-male sperm precedence regardless of male size still holds for complete litters. We explored the relationship between male mating order, male size, timing of mating and relatedness on paternity success. Females were mated with two males of different size with either the large or the small male first, with 1 day rest between the matings. Matings continued for 6 h. In these controlled conditions male size did not have a strong effect on paternity success, but mating order did. Males mating second sired 69.5% of the offspring. Within first mated males, males that mated closer to ovulation sired more offspring. To a lesser degree, variation appeared also to be caused by differences in genetic compatibility of the female and the male, where high levels of allele-sharing resulted in lower paternity success.
Body size does not predict species richness among the metazoan phyla
Authors: Orme C. D. L. , Quicke D. L. J. , Cook J. M. , Purvis A.
Published: March 2003

We present a comparative study of the relationship between body size and described taxonomic diversity in the Metazoa. We find no pattern between body size and taxonomic diversity; neither the smallest organisms nor organisms at an intermediate body size are consistently more diverse than their closest relatives. This conclusion holds for both nonphylogenetic analysis, in which phyla are treated as independent points, and analysis of independent contrasts using several recent hypotheses of metazoan phylogeny. These results appear surprising in the context of existing models of body size distributions. However, such models are built around the prevalence of right-skewed distributions and we find no evidence for such a distribution.
High resolution analysis of mating systems: inbreeding in natural populations ofPinus radiata
Authors: Vogl C. , Karhu A. , Moran G. , Savolainen O.
Published: March 2003

Pinus radiata has a history of population bottlenecks and is currently restricted to five relatively small populations, three in mainland California, and two on islands off the coast of Baja California. Using highly polymorphic microsatellite markers and a newly developed statistical approach, we were able to estimate individual inbreeding coefficients and can thus analyse the mating system with high resolution. We find a bimodal distribution of inbreeding coefficients: most individuals result from selfing whereas few (in the mainland populations) to a modest number (in the island populations) are likely selfed. In most other pine species and presumably in the ancestral P. radiata population, occurrence of mature selfed individuals would be impossible because of the high genetic load. We therefore conclude that inbreeding depression has been purged in P. radiata and that the mating system has changed as a consequence.
Genetic polymorphism in Caulerpa taxifolia (Ulvophyceae) chloroplast DNA revealed by a PCR-based assay of the invasive Mediterranean strain
Authors: . Famà P , Jousson O. , Zaninetti L. , Meinesz A. , Dini F. , Di Giuseppe G. , Millar A. J. K. , Pawlowski J.
Published: March 2003

An invasive, cold-tolerant strain of the tropical green alga Caulerpa taxifolia was introduced recently in the Mediterranean Sea and along the Californian coast. We screened 50 aquarium and open-sea C. taxifolia specimens for the presence/absence of an intron located in the rbcL gene of chloroplast DNA. We also reanalysed a total of 229 sequences of the Internal Transcribed Spacer (ITS) of ribosomal DNA, combining previously published sequences from different studies with 68 new sequences to complement rbcL data. The introduced Mediterranean strain was found to be characterized by the absence of the rbcL intron and by the occurrence of a particular monomorphic ITS type. A PCR assay based on rbcL gene was developed to detect new introductions of the invasive strain of C. taxifolia. This rapid and inexpensive test could be useful to assist environment managers in the preservation of coastal marine ecosystems.
Phylogeny and adaptive radiation in the Onychopoda (Crustacea, Cladocera): evidence from multiple gene sequences
Authors: Cristescu M. E. A. , Hebert P. D. N.
Published: March 2003

Members of the order Cladocera show remarkable morphological and ecological diversity. One of the most spectacular adaptive radiations in this group has involved species of the suborder Onychopoda, which have adopted a novel feeding strategy, predation, and have colonized habitats with a broad range of salinities. In order to evaluate the origins and systematics of this group, we derived a molecular phylogeny for its three component families including nine of 10 recognized genera based on three mitochondrial (mt) gene sequences: cytochrome c oxidase subunit I (COI), the ribosomal small and large subunits (12S and 16S) and one nuclear gene sequence: the small ribosomal subunit (18S). Maximum-parsimony, maximum-likelihood and neighbour-joining phylogenetic analyses were largely congruent, supporting the monophyly of the suborder and each of its families. Comparative analyses of data based on total evidence and the conditional combination of the ribosomal genes produced relatively congruent patterns of phylogenetic affinity. By contrast, analyses of single gene results were inconsistent in recovering the monophyletic groups identified by the multigene analyses. Based on the reconstructed phylogeny, we discriminate among the existing hypotheses regarding the evolutionary history of the onychopods. We identify a prolonged episode of speciation from the Miocene to the Pleistocene with two pulses of diversification. We discuss our results with reference to the geological history of the Ponto-Caspian basin, the region which fostered the onychopod radiation.
Ectoparasites cause increased bilateral asymmetry of naturally selected traits in a colonial bird
Authors: Brown Charles R. , Brown Mary Bomberger
Published: March 2003

Parasitism has been shown to correlate with levels of bilateral symmetry in some organisms, with more asymmetric individuals often having more parasites. However, few studies have shown experimentally that parasitism directly causes increased asymmetry. By fumigating some cliff swallow (Petrochelidon pyrrhonota) colonies and leaving others untreated, we investigated experimentally whether ectoparasitism by the cimicid swallow bug led to higher levels of asymmetry in length of wings, outer tail feathers, and tarsus among juvenile and adult birds. Juveniles from fumigated colonies measured soon after fledging had significantly less asymmetry in wing and outer tail length than juveniles from nonfumigated colonies; asymmetry in tarsus length was unaffected by parasitism. Adults that had undergone one or more post-juvenal molts on the wintering grounds showed no differences in asymmetry between those reared in fumigated vs. nonfumigated colonies. These results show that ectoparasitism directly leads to increased feather asymmetry in cliff swallows, probably through parasite-induced nutritional stress. Because wing and tail asymmetry impair flight performance and reduce foraging efficiency, the increased asymmetry caused by parasites represents a fitness cost to cliff swallows. This is among the few experimental studies to show an effect of parasites on asymmetry of naturally selected characters.
Evolution of dispersal in metapopulations with local density dependence and demographic stochasticity
Authors: Parvinen K. , Dieckmann U. , Gyllenberg M. , Metz J. A. J.
Published: March 2003

In this paper, we predict the outcome of dispersal evolution in metapopulations based on the following assumptions: (i) population dynamics within patches are density-regulated by realistic growth functions; (ii) demographic stochasticity resulting from finite population sizes within patches is accounted for; and (iii) the transition of individuals between patches is explicitly modelled by a disperser pool. We show, first, that evolutionarily stable dispersal rates do not necessarily increase with rates for the local extinction of populations due to external disturbances in habitable patches. Second, we describe how demographic stochasticity affects the evolution of dispersal rates: evolutionarily stable dispersal rates remain high even when disturbance-related rates of local extinction are low, and a variety of qualitatively different responses of adapted dispersal rates to varied levels of disturbance become possible. This paper shows, for the first time, that evolution of dispersal rates may give rise to monotonically increasing or decreasing responses, as well as to intermediate maxima or minima.
Heritability of resistance against ectoparasitism in the Drosophila–Macrocheles system
Authors: Polak M.
Published: March 2003

Ectoparasites are abundant in natural communities, can have pronounced deleterious fitness consequences to their host and are important vectors of transmissible parasitic disease. Yet very few studies have estimated the magnitude of heritable genetic variation underlying resistance against ectoparasitism, which significantly limits our ability to predict the evolution of this ecologically important character. The present paper reports results of artificial selection for increased resistance in Drosophila nigrospiracula against ectoparasitic, haematophagous mites, Macrocheles subbadius. In this system, which occurs naturally in the Sonoran Desert of North America, ectoparasitism significantly damages the expression of host fitness traits, including longevity, fecundity and male mating success. In the present study, resistance, which was modelled as a threshold trait, responded significantly to selection applied on either sex. Realized heritability, calculated as a mean across four replicates, was estimated to be 0.152 ± 0.014 (SE). The heritability estimate from selection on males did not differ from that on females, but both estimates differed significantly from zero. This documented presence of additive genetic variation for resistance, coupled with knowledge of the fitness consequences of ectoparasitism, indicates that the host population possesses significant evolutionary potential. Selection was applied on the pre-attachment phase, thereby targeting behavioural forms of defence. This study therefore establishes parallels between insects and other animals in their ability to protect themselves and evolve behavioural defences against ectoparasites.
A phallus for free? Quantitative genetics of sexual trade-offs in the snail Bulinus truncatus
Authors: Ostrowski M.-F. , Jarne P. , David P.
Published: March 2003

Resource allocation is thought to play a key role in the coexistence of different sexual morphs within hermaphroditic species. Indeed, most models assume that sexual functions are subject to a balance between reproductive advantage and energetic cost. Various types of cost (e.g. organ construction, maintenance and utilization) and levels of trade-off (physiological and genetic) may be considered. We here examine physiological and genetic costs of phallus construction and maintenance in Bulinus truncatus, a snail species in which aphallic individuals (without phallus) coexist with regular hermaphrodites. We use a quantitative genetic design involving 37 inbred lines (four populations) known to produce different proportions of aphallics, to test for the existence of genetic and nongenetic correlations between aphally and a range of life-history traits over the totality of the life cycle. Our results show that aphallic and euphallic individuals of the same line do not show consistent differences in either growth, fecundity (including offspring survival), or longevity. Furthermore, none of these traits is genetically correlated across lines with the frequency of the aphallic morph. We conclude that the cost of the construction and maintenance of the phallus must be very low in this species. Future studies should investigate the cost associated with using the phallus (i.e. male outcrossing behaviour) to explain the maintenance of high frequencies of aphallic individuals in natural populations.
Treatment with plasmapheresis and intravenous immunoglobulin in pregnancies complicated with anti‐PP1Pk or anti‐K immunization: a report of two patients
Authors: Fernández‐Jiménez M. C. , Jiménez‐Marco M. T. , Hernández D. , González A. , Omeñaca F. , De La Cámara C.
Published: March 2003

Background and Objectives

In addition to anti‐D alloantibody, other antibodies such as anti‐K antibody and anti‐PP1Pk antibody have been reported to cause severe haemolytic disease of the newborn (HDN). HDN caused by anti‐K results not only from destruction of red cells but also from suppression of erythropoiesis. Anti‐PP1Pk has been associated with abortion early in pregnancy. We report on two patients, one with anti‐PP1Pk and the other with anti‐K, who were treated with plasmapheresis and intravenous immunoglobulin (IVIG) during pregnancy in an attempt to reduce the plasma antibody levels.

Materials and Methods

The patient with anti‐PP1Pk had lost all seven previous fetuses in the first trimester and therefore therapy in this patient was started at 8 weeks of gestation. The second patient had been sensitized to the K antigen through blood transfusion and had had two intrauterine fetal deaths at 26 weeks of gestation with signs of hydrops fetalis. Treatment in this patient was started during the 16th week of pregnancy.

Results

As a result of therapy, the antibody titre was reduced in both patients. In the first patient a healthy infant was delivered by Caesarean section at 37 weeks of gestation. The second patient gave birth at 36 weeks of gestation. Neither newborn required exchange transfusion.

Conclusions

In our two patients, plasmapheresis combined with IVIG proved successful in the management of fetomaternal incompatibilities where the mechanism of fetal loss differs from the classical anti‐D.
Effects of solvent/detergent‐treated plasma and fresh‐frozen plasma on haemostasis and fibrinolysis in complex coagulopathy following open‐heart surgery
Authors: Haubelt H. , Blome M. , Kiessling A. H. , Isgro F. , Bach J. , Saggau W. , Hellstern P.
Published: March 2003

Background and Objectives Solvent/detergent‐treated plasma (SDP) contains markedly lower protein S (PS) and plasmin inhibitor (PI) activity than standard fresh‐frozen plasma (FFP). It has also been reported that SDP contains no α1‐antitrypsin. Despite the lack of clinical data, it is suspected that SDP may be less effective than FFP in the treatment of complex coagulopathies. We therefore conducted a prospective trial to study the impact of SDP and FFP on haemostasis and fibrinolysis in complex coagulopathy after open‐heart surgery.

Materials and Methods Patients received either 600 ml of SDP (n = 36) or 600 ml of FFP (n = 31) at an infusion rate of 30 ml/min. The following parameters were measured before treatment and 60 min after termination of plasma infusion: prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, factor VIII, antithrombin, protein C (PC), free PS and PS activity, prothrombin fragments F1+2 (F1+2), d‐dimers (DD), fibrinogen degradation products (FDP), plasmin–plasmin inhibitor complexes (PPI), plasminogen, PI and α1‐antitrypsin.

Results The rise in fibrinogen, factor VIII, antithrombin, PC, free PS, α1‐antitrypsin and plasminogen, and the decrease in PT and APTT, did not significantly differ between the two study arms. However, PS activity did not increase after SDP infusion but did show a significant elevation after infusion with FFP. PI declined significantly after SDP and remained uninfluenced by FFP. Neither SDP nor FFP had any significant influence on F1+2, DD or FDP. However, a significant decrease in PPI levels caused by both types of plasma indicated a reduction in hyperfibrinolysis. Clinical haemostasis evaluation revealed no significant difference between the two treatment regimens. No adverse reactions were observed.

Conclusion With the exception of PS and PI, SDP and FFP improved haemostasis and fibrinolysis to a similar degree. The clinical significance of these findings has to be determined in patients with severe acquired PS and PI deficiency requiring plasma transfusions.
Quality control of leucoreduced cellular blood components in France
Authors: Chabanel A. , Andreu G. , Carrat F. , Hervé P.
Published: March 2003

Background and Objectives Since 1 April 1998, all cellular blood components in France have been leucoreduced. The current French standard is < 1 × 106 white blood cells (WBC) per unit with a 95% confidence that at least 97% of units will meet this standard.

Materials and methods Quality control (QC) data for leucoreduced cellular blood components were collected from the 41 French blood centres over a 5‐month period. Conformance to the standard was determined using a non‐parametric approach.

Results More than 98% of the 15 286 red cell concentrates and of the 2895 platelet concentrates tested had < 1 × 106 WBC per unit. One filtration device gave unsatisfactory results and its use was discontinued.

Conclusion This QC survey shows an overall compliance with the standard. The data illustrate the practical value of identifying devices or centres with consistent QC problems.
Cytokine release in febrile non‐haemolytic red cell transfusion reactions
Authors: Lin J.‐S. , Tzeng C.‐H. , Hao T.‐C. , Hu H.‐Y. , Ho Y.‐T. , Lyou J.‐Y. , Liu J. M. , Ho C.‐H. , Yung C.‐H.
Published: March 2003

Background and Objectives The aim of this study was to elucidate the role and identity of cytokines involved in febrile non‐haemolytic red cell transfusion reactions (FNHTRs).

Materials and Methods Eighty‐one patients experiencing transfusion reactions after receiving packed red blood cells (RBCs) were divided into three groups, as follows, based on the reaction experienced: FNHTRs (n = 60); chills without fever (n = 8); and allergic reaction with urticaria (n = 13). The concentrations of interleukin (IL)‐1β, IL‐6, IL‐8 and tumour necrosis factor (TNF)‐α were measured in the packed transfused unit and patients’ plasma by using enzyme immunoassays. Wilcoxon’s matched‐pairs signed test was used to compare the difference in cytokine levels in patients’ plasma before and after transfusion. The Kruskal–Wallis test was used first, followed by the Mann–Whitney test, to compare the pretransfusion cytokine levels in patients’ plasma between groups and to compare the cytokine levels in packed RBCs transfused to each group of patients.

Results The age of the implicated packed RBC was 11·5 ± 5·7 days. Significant increases were observed in IL‐6 (P < 0·001) and IL‐8 (P < 0·001) patients’ plasma levels, but not in IL‐1β or TNF‐α levels, in those patients exhibiting FNHTR. No changes were observed in the patients’ plasma samples of the other groups. Cytokine levels in the RBC concentrate supernatants were not appreciably elevated.

Conclusions Transfusion of packed RBCs may significantly increase intravascular levels of IL‐6 and IL‐8 in patients with FNHTRs.
RHCE‐D‐CEhybrid genes can cause false‐negative DNA typing of the Rh e antigen
Authors: Hundhausen T. , Petershofen E. K. , Doescher A. , Bauerfeind U. , Müller T. H. , Schunter F.
Published: March 2003

Background and ObjectivesDNA typing of the human Rh blood groups generally shows good agreement with serologically defined phenotypes. However, in the present report we describe four individuals who were declared Rh e negative by genotyping although they express the Rh e antigen.

Materials and MethodsSerotyping was performed using mono‐ and polyclonal Rh antisera. Fluorescent multiplex sequence‐specific polymerase chain reactions (PCR–SSPs) identifiedRHDexons and the polymorphisms usually associated with the Rh E/e or Rh C/c/Cwantigens. Additional PCR amplification reactions, which were carried out to revealRHCE‐D‐CEhybrid genes, analysed exon 5 of theRHgenes, the location of the polymorphism (676C→G) coding for the Rh E and Rh e antigens.

ResultsFour individuals were identified who expressed Rh e antigens but were negative by PCR–SSP typing for commonRhe‐coding sequences. In one family analysed in detail, anRHCE‐D5‐CEhybrid gene associated with Rh e antigen expression was identified. A concomitantRHcEallele accounted for a seemingly regular typing pattern by conventionalRHPCR.

ConclusionsThe presence ofRHCE‐D5‐CEhybrid alleles may cause false‐negative DNA‐typing results for the Rh e antigen that are easily overlooked unless appropriateRHhybrid PCR–SSPs are incorporated into conventional DNA‐typing protocols. These and previous data strongly caution against an uncritical interpretation ofRHDNA‐typing results.
Inactivation of pathogens in platelet concentrates by using a two‐step procedure
Authors: Mohr H. , Redecker‐Klein A.
Published: March 2003

Background and ObjectivesPlatelet concentrates are contaminated with residual leucocytes and may also be infected with viruses and bacteria. We investigated whether these pathogens can be inactivated by a two‐step procedure comprising photodynamic treatment in the presence of the phenothiazine dye, thionine, followed by irradiation with ultraviolet light (UV‐B, wavelength range 290–330 nm).

Materials and MethodsPlatelet concentrates were prepared from buffy coats. The concentrates were spiked with different viruses, bacteria and leucocytes, then illuminated with yellow light in the presence of thionine at dye concentrations between 1 and 5 µmand with UV‐B at doses up to 2·4 J/cm2. The infectivity of samples and the viability of leucocytes were assayed before and after treatment. The influence of treatment onin vitroplatelet function was also examined.

ResultsThe inactivation of free viruses in platelet concentrates by photodynamic treatment with thionine/light was significantly enhanced when it was followed by irradiation with UV‐B. The inactivation of leucocytes and of bacteria by UV‐B was improved when it was preceded by thionine/light. Sterile platelet concentrates were prepared from buffy coats infected withStaphylococcus epidermidis. Platelet function and the storage stability of platelet concentrates were only moderately influenced by the two decontamination steps.

ConclusionsPhotodynamic treatment in the presence of the phenothiazine dye, thionine, followed by low‐dose UVB, has the potential to inactivate viruses, leucocytes and bacteria, which might contaminate platelet concentrates. Both treatments complement each other.
Successful ventilatory management of post‐anesthetic airway collapse and hypoxemia in a dog
Authors: Aldrich Janet , Hopper Kate , Johnson Lynelle , Haskins Steve
Published: March 2003

AbstractObjective:To report a life‐threatening complication (airway collapse) associated with a common procedure (anesthesia) and to describe its successful management.

Case Summary:A dog without pre‐existing signs of respiratory disease developed hypoxemia and severe atelectasis in the post‐anesthetic recovery period and was demonstrated, by bronchoscopic examination, to have severe airway collapse. Mechanical ventilation was used to re‐expand collapsed lung units and to prevent re‐collapse. A ventilation strategy designed to minimize airway and alveolar trauma was used. The dog was successfully weaned from the ventilator and made a full recovery.

Unique Information Provided:Acute, severe hypoxemia due to airway collapse occurred in the post‐operative period in a dog with no signs of pre‐existing respiratory disease. The dog was successfully managed with short‐term mechanical ventilation. High frequency jet ventilation was used for a diagnostic bronchoscopy.
The role of albumin replacement in the critically ill veterinary patient
Authors: Mazzaferro Elisa M. , Rudloff Elke , Kirby Rebecca
Published: March 2003

Objective:To review the human and veterinary literature on the physiological role and effects of therapeutic albumin supplementation.

Data sources:Data from human and veterinary literature was reviewed.

Human data synthesis:Hypoalbuminemia often occurs in a variety of critical illnesses, and contributes to the development of life‐threatening complications, including pulmonary edema, delayed wound healing, feeding intolerance, hypercoaguability, and multiple organ dysfunction. Serum albumin concentration has been used as a prognostic indicator in cases of chronic hypoalbuminemia. The use of albumin replacement therapy in humans is sometimes controversial, but may be associated with improved morbidity and decreased mortality.

Veterinary data synthesis:Unlike human literature, there is a paucity of controlled clinical studies in the literature regarding albumin supplementation in veterinary patients. Rather, the majority of published studies were performed in experimental animals or via retrospective analyses. One recent study evaluated the use of plasma to improve albumin concentration in dogs with hypoalbuminemia. Other older studies investigated wound healing in dogs with experimentally induced hypoalbuminemia. As in human medicine, serum albumin concentration may be helpful as a prognostic indicator in critically ill dogs.

Conclusion:Albumin is one of the most important proteins in the body because of its role in maintenance of colloid oncotic pressure, substrate transport, buffering capacity, as a mediator of coagulation and wound healing, and free‐radical scavenging. Albumin replacement in veterinary medicine is difficult, but until prospective clinical trials determine the efficacy of albumin replacement are conducted, a suggested clinical guideline would be to maintain albumin concentration at or above 2.0 g/dl utilizing fresh frozen plasma.
Flag Leaf Senescence, as Evaluated by Numerical Image Analysis, and its Relationship with Yield under Drought in Durum Wheat
Authors: Hafsi M. , Mechmeche W. , Bouamama L. , Djekoune A. , Zaharieva M. , Monneveux P.
Published: March 2003

Senescence was evaluated at different stages of the grain‐filling period in eight durum wheat varieties using numerical image analysis (NIA). The varieties were grown under early, severe drought conditions on the high plains of Sétif in Algeria. After flowering, three different irrigation treatments were applied. Treatment effect was small, while a genotypic effect was noted for most of the senescence parameters. Senescence correlated to biomass, while the maximal rate of senescence, Vsmax, correlated to thousand‐kernel weight. The potential of the method of numerical image analysis for monitoring flag leaf senescence, detecting genotypic variability and selecting genotypes with delayed senescence is discussed.
Characterization of Growth, Nitrogen Accumulation and Competitive Ability of Six Tropical Legumes for Potential Use in Intercropping Systems
Authors: Akanvou R. , Bastiaans L. , Kropff M. J. , Goudriaan J. , Becker M.
Published: March 2003

Legume cover crops can be successfully used as intercrop or relay crops in low‐input farming systems. To select appropriate species for intercropping, experiments were conducted in the savannah zone of Côte d’Ivoire during the wet seasons of 1997 and 1998 to determine the growth and nitrogen (N) accumulation of six cover legumes as well as the characteristics indicative of competitive ability. The species included the erect growingCrotalaria junceaandCajanus cajan, the creeping speciesMucuna pruriensvar.cochinchinensisandCalopogonium mucunoidesand the bushy herbaceous speciesAeschynomene histrixandStylosanthes hamata. Marked differences in phenology were observed asS. hamataandC. junceaflowered around 45–55 days after sowing (DAS) and the other species around 80–95 DAS.C. junceaandC. cajanproduced close to 9 ton dry matter ha–1, whereas the other species produced less than half this amount. The average estimated amount of accumulated N, based on leaf material, was around 70 kg ha–1for all species exceptS. hamataandA. histrix, which only produced around 25 kg ha–1. Based on morphological characteristics,C. juncea,C. cajanand the short‐livedM. prurienswere identified as potentially most competitive, indicating that productivity and competitive ability are strongly linked. The implications of these findings for intercropping systems in upland rice production are discussed.
Dry Matter Accumulation in Linseed (Linum usitatissimum L.)*
Authors: Hassan F. U. , Leitch M. H.
Published: March 2003

Field experiments were conducted at the Marfa Mawr field station of the University of Wales, Aberystwyth, over 2 years to study the effects of seeding density and row spacing on dry matter accumulation in linseed (Linum usitatissimum L.). Dry matter accumulation increased progressively in all the densities and row spacings with the age of the plants during both the years. However, during 1993 a reduction in dry matter was observed between 106 days after sowing (DAS) and maturity (138 DAS), but this did not happen during 1994. This reduction was considered to be the effect of lodging of the crop and leaf senescence. The lodging took place due to heavy showers of rain and high winds near maturity, and plants were not able to support the weight of capsules. The greater amount of total dry matter accumulated during 1993 compared to 1994 was related to climatic conditions (moist and relatively cool in 1993) on one hand and the total length of the crop life cycle on the other. A total of 391 mm of rain was received during the crop life cycle during 1993 while 229 mm of rain was recorded during 1994. A difference of 2 °C in mean temperature between 1993 and 1994 was also recorded.