The transcriptional landscape of polyploid wheat.

The coordinated expression of highly related homoeologous genes in polyploid species underlies the phenotypes of many of the world's major crops. Here we combine extensive gene expression datasets to produce a comprehensive, genome-wide analysis of homoeolog expression patterns in hexaploid bread wheat. Bias in homoeolog expression varies between tissues, with ~30% of wheat homoeologs showing nonbalanced expression. We found expression asymmetries along wheat chromosomes, with homoeologs showing the largest inter-tissue, inter-cultivar, and coding sequence variation, most often located in high-recombination distal ends of chromosomes. These transcriptionally dynamic genes potentially represent the first steps toward neo- or subfunctionalization of wheat homoeologs. Coexpression networks reveal extensive coordination of homoeologs throughout development and, alongside a detailed expression atlas, provide a framework to target candidate genes underpinning agronomic traits in wheat.

Superior mesenteric artery syndrome: a single centre experience of laparoscopic duodenojejunostomy as the operation of choice.

INTRODUCTION The superior mesenteric artery (SMA) syndrome, or Wilkie's syndrome, is a rare cause of postprandial epigastric pain, vomiting and weight loss caused by compression of the third part of the duodenum as it passes beneath the proximal superior mesenteric artery. The syndrome may be precipitated by sudden weight loss secondary to other pathologies, such as trauma, malignancy or eating disorders. Diagnosis is confirmed by angiography, which reveals a reduced aorto-SMA angle and distance, and contrast studies showing duodenal obstruction. Conservative management aims to increase intra-abdominal fat by dietary manipulation and thereby increase the angle between the SMA and aorta. Where surgery is indicated, division of the ligament of Treitz, anterior transposition of the third part of the duodenum and duodenojejunostomy have been described. METHODS We present four cases of SMA syndrome where the intention of treatment was laparoscopic duodenojejunostomy. The procedure was completed successfully in three patients, who recovered quickly with no short-term complications. A fourth patient underwent open gastrojejunostomy (complicated by an anastomotic bleed) when dense adhesions prevented duodenojejunostomy. CONCLUSIONS The superior mesenteric artery syndrome should be considered in patients with epigastric pain, prolonged vomiting and weight loss. Laparoscopic duodenojejunostomy is a safe and effective operation for management of the syndrome. A multi-speciality team approach including gastrointestinal, vascular and radiological specialists should be invoked in the management of these patients.

Hydride & dihydrogen complexes of earth abundant metals: structure, reactivity, and applications to catalysis.

Recent developments in the chemistry of hydride and dihydrogen complexes of iron, cobalt, and nickel are summarized. Applications in homogeneous catalysis are emphasized.

Gallbladder agenesis.

This case report describes unusual congenital biliary anatomy encountered at a routine laparoscopic cholecystectomy. Imaging obtained prior to surgery (ultrasonography and magnetic resonance cholangiopancreatography) had been misleading. The case highlights the importance of careful dissection even with anticipated normal anatomy.

'Time critical' rapid amputation using fire service hydraulic cutting equipment.

INTRODUCTION: Entrapped trauma victims require extrication, which, on rare occasions, may involve amputation of a limb. Standard extrication techniques sometimes fail or may be impossible, leading to the death of the entrapped victim. We propose that the use of fire service hydraulic cutting equipment can be used effectively to urgently amputate a limb, where conventional techniques are unusable. METHOD: The study aims to determine: (i) the potential use of this equipment to achieve expeditious life-saving amputations and (ii) the effect the fire service hydraulic cutting equipment has on the bony and surrounding soft tissues. Initially a porcine limb was used followed by fresh-frozen cadaveric lower limbs. We recorded the time, number of cuts, proximal fracture propagation and quality of bone cut when performing amputations at five levels. RESULTS: The experiment confirms that faster guillotine amputations in human cadaveric lower limb specimens can be achieved by using fire service hydraulic cutting equipment. Overall, the average time to complete an amputation in these ideal experimental circumstances at all five levels was quicker using the hydraulic cutting equipment. Either one or two cutting actions were required to achieve the amputation using fire service hydraulic cutting equipment. The degree and proximal extent of the comminution were greater using the fire service hydraulic cutting equipment. CONCLUSION: If circumstances and time constrains allow, a conventional amputation technique carried out by a trained medical practitioner would be preferable to the use of the fire service hydraulic cutting equipment. However, we feel that this technique could be used to perform emergent amputation under trained medical supervision, if it is felt that a standard amputation technique would take too long or the environment is too restrictive to perform a standard amputation safely.

The effects of exposure to an acute naturalistic stressor on working memory, state anxiety and salivary cortisol concentrations.

Exposure to an acute naturalistic stressor induces both psychological and physiological changes in humans. The two studies reported here explored the impact of exposure to an acute naturalistic stressor on state anxiety, working memory and HPA axis activation (salivary cortisol). In both experiments, ten healthy male participants were exposed to an acute naturalistic stressor, helicopter underwater evacuation training (HUET), and their physiological and behavioural responses before (first study) and after (second study) the stressor were compared to ten non-stressed controls. The results of both experiments showed that working memory performance was preserved during anticipation of an acute stressor, but impairments were observed immediately after stress exposure. Participants reported significantly higher state anxiety levels during anticipation and following stress exposure, whereas significant elevations in cortisol levels were only observed 25 min post exposure to stress, but not before or immediately after stress exposure. The results of both experiments demonstrated a dissociation between behavioural and biochemical measures and provided evidence for a dissociation of the effects of stress on cognitive and physiological measures depending on the time of testing, with cognitive impairments most evident following stress exposure.

2nd to 4th digit ratio and a universal mean for prenatal testosterone in homosexual men.

Male homosexuals are said to have experienced high prenatal testosterone, and testosterone may have deleterious effects on the immune system. The question of the prenatal androgen status of male homosexuals is therefore of importance. There is evidence that the relative length of the 2nd and 4th digit (2D:4D) is negatively correlated with prenatal testosterone. We review the available literature, and provide further data on 2D:4D in male heterosexuals and homosexuals. Normative values of male mean 2D:4D ratio vary between 0.94 to 1.00 across populations. However, mean 2D:4D ratio is relatively constant among male homosexuals from different populations, with a mean of 0.96 to 0.97. Therefore homosexuals appear to be more androgenised (lower 2D:4D) than heterosexuals in some populations, while in others they appear to be less androgenised (higher 2D:4D) than heterosexuals. Speculations regarding the effect of early sex steroids on the health of male homosexuals should therefore focus on the effects of prenatal testosterone levels associated with 2D:4D ratios of between 0.96 and 0.97.

Quantitative genetic analysis of natural variation in body size in Drosophila melanogaster.

Latitudinal, genetic variation in body size is a commonly observed phenomenon in many invertebrate species and is shaped by natural selection. In this study, we use a chromosome substitution and a quantitative trait locus (QTL) mapping approach to identify chromosomes and genomic regions associated with adaptive variation in body size in natural populations of Drosophila melanogaster from the extreme ends of clines in South America and Australia. Chromosome substitution revealed the largest effects on chromosome three in both continents, and minor effects on the X and second chromosome. Similarly, QTL analysis of the Australian cline identified QTL with largest effects on the third chromosome, with smaller effects on the second. However, no QTL were found on the X chromosome. We also compared the coincidence of locations of QTL with the locations of five microsatellite loci previously shown to vary clinally in Australia. Permutation tests using both the sum of the LOD scores and the sum distance to nearest QTL peak revealed there were no significant associations between locations of clinal markers and QTL's. The lack of significance may, in part, be due to broad QTL peaks identified in this study. Future studies using higher resolution QTL maps should reveal whether the degree of clinality in microsatellite allele frequencies can be used to identify QTL in traits that vary along an environmental gradient.

What causes inefficient transmission of male-killing Wolbachia in Drosophila?

Selfish genetic elements that distort the sex ratio are common in arthropods. Theory predicts they will invade and spread to fixation if they are vertically transmitted with perfect fidelity, potentially leading to host extinction. For inherited microorganisms that distort the sex ratio, inefficient vertical transmission or incomplete sex ratio distorting ability is required for host persistence. However, the relative roles of genetic and environmental factors in permitting the survival of male hosts and preventing parasite transmission are poorly understood. We examined the causes of transmission infidelity and male survival for a male-killing Wolbachia strain in Drosophila bifasciata. Under standard laboratory conditions (18 degrees C), in its standard genetic background, males are produced very rarely, and no case of reversion has been observed in 20 generations of laboratory rearing. To investigate the role of host genetic factors, Wolbachia was crossed into 27 different inbred lines of D. bifasciata, but in no case was reversion observed at preferred environmental temperatures. The role of elevated temperature in inducing inefficient transmission was examined. Whilst vertical transmission was perfect over three generations of maintenance at 23.5 degrees, transmission infidelity was observed at 25 degrees. We conclude that there is no evidence for the presence of either fixed or polymorphic host genes that repress transmission at standard environmental temperatures. However, severe temperature treatment does make vertical transmission imperfect. We suggest that the case of Wolbachia in D. bifasciata is one that is naturally balanced, the population being maintained polymorphic without the evolution of host resistance genes.

Temperature and clinal variation in larval growth efficiency in Drosophila melanogaster.

Geographic clines in ectotherm species including Drosophila melanogaster have been found throughout the world, with genetically larger body size and shorter development time occurring at high latitudes. Temperature is thought to play a major role in the evolution of this clinal variation. Laboratory thermal selection has effects similar to those seen in geographical clines. Evolution at low temperatures results in more rapid development to larger adult flies. This study investigated the effects of geographical origin and experimental temperature on larval growth efficiency in D. melanogaster. Larvae from populations that had evolved at high latitudes were found to use limited food more efficiently, so that the overall adult body size achieved was larger. Larvae reared at a lower experimental temperature (18 °C) used food more efficiently than those reared at a higher temperature (25 °C). The increases in growth efficiency found in populations from high latitudes could explain their increased body size and more rapid development.

Starvation resistance and adult body composition in a latitudinal cline of Drosophila melanogaster.

Latitudinal geographic variation in Drosophila melanogaster is pervasive. Parallel clines in traits such as body size, egg size, ovariole number, and development time have been found on several continents throughout the world. However, a cline in starvation resistance and fat content in D. melanogaster has so far been found only in India. Here we investigate starvation resistance and fat content in 10 populations from South America, in which clines in body size, egg size, and development time have previously been found. We find no evidence for a cline in starvation resistance or fat content in South America. We therefore suggest that the cline in starvation resistance in India may have evolved in response to specific climatic variation found only in India.

Stress distribution in the single-unit osseointegrated dental implant: finite element analyses of axial and off-axial loading.

Occlusal overload may contribute to the extensive crestal bone loss often noted around late-failure dental implants. A particularly high risk of traumatic overload occurs with the posterior single-unit implant restoration because the restoration itself is usually wider than the implant, creating the potential for a cantilever effect with high bending moments. The objective of this study was to evaluate the simulated effects of axial and off-axial vertical loads on stress gradients at the implant/bone interface of a single-unit osseointegrated root-form endosseous dental implant. A two-dimensional finite element model was generated. A 490-N load was applied at 0, 2, 4, and 6 mm from the vertical axis of the implant. Off-axis loading resulted in greatly increased compressive stresses within the crestal cortical bone on the side to which the load was applied and similarly increased tensile stresses on the side opposite the load. These stresses increased considerably with each mm increase off axis of the applied load. These data suggest that off-axis loading of single-unit implant restorations provides a significant contribution to increased stresses at the implant/cortical bone interface. The distance off axis at which the load is applied is also significant.

Modulation of oviductal transport in mares by local application of prostaglandin E2.

Equine embryos enter the uterus 144-156 h after ovulation, before which time the passage of embryos through the oviduct is halted in the region of the ampullary-isthmic junction. It is thought that further onward movement of embryos to the uterus is facilitated by secretion of prostaglandin E2 (PGE2) by the embryos, which relaxes the smooth muscle of the isthmus. In the present study, the effect of a single local application of PGE2 on oviductal transport was examined in 22 Thoroughbred and Pony mares that were inseminated on alternate days during oestrus. On day 4 after ovulation, the ipsilateral ovary, oviduct and tip of the uterine horn were visualized by flank laparoscopy, and either a commercial preparation of PGE2 suspended in a triacetin-based gel or a control gel containing no PGE2 was dripped along the external surface of the oviduct. On day 5, the uterus of each mare was flushed three times with phosphate-buffered saline containing 1% (v/v) fetal bovine serum and, if no embryo was recovered, the flushing procedure was repeated on day 7 or 8. Overall, the embryo recovery rate was similar in PGE2-treated and control mares (65 and 63%, respectively). However, the recovery rate of embryos on day 5 was significantly higher for PGE2-treated mares than for control mares (60 versus 0%; P < 0.01), indicating an increased rate of embryo transport in PGE2-treated mares. Furthermore, unfertilized oocytes were recovered from nine of the PGE2-treated mares on day 5 but from none of the control mares. All of the embryos recovered on day 5 were compacted morulae, whereas all of those recovered on days 7 or 8 were expanding blastocysts. The results of the present study support the role of embryonic PGE2 in oviductal transport in mares. The results also demonstrate that a single local application of PGE2 is a simple and practical method for speeding the passage of embryos through the oviduct for nonsurgical recovery of morulae from the uterus.

GRID and Multiphonon States.

The development of the GRID technique for determining nuclear level lifetimes of excited low-spin states populated in thermal neutron capture reactions has resulted in the ability to perform detailed studies of proposed multiphonon excitations for the first time. This paper discusses the experimental evidence for multiphonon excitations determined using the GRID technique. In deformed nuclei several good examples of γγK(π) = 4(+) excitations have been established, whereas the experimental evidence gathered on K(π)= 0(+) bands is contradictory, and any interpretations will likely involve the mixing of several different configurations. In vibrational nuclei the GRID technique has helped to establish the existence of multiple quadrupole phonon excitations in (114)Cd, and an almost complete set of quadrupole-octupole coupled states in (144)Nd.

Body composition of preterm infants during infancy.

AIMS: To examine body composition in preterm infants. METHODS: Body composition was measured by dual energy x-ray absorptiometry (DEXA) at hospital discharge, term, 12 weeks, and at 6 and 12 months corrected age in 125 infants (birthweight < or = 1750 g, gestational age < or = 34 weeks). RESULTS: Body weight derived by DEXA accurately predicted that determined by conventional scales. In both sexes lean mass (LM), fat mass (FM), %FM, bone area (BA), bone mineral mass (BMM), and bone mineral density (BMD) increased rapidly during the study; significant changes were detectable between discharge and term. At 12 months, LM, BA, and BMM, but not FM, %FM, or BMD were greater in boys than in girls. Corrected for age, LM was less than those of the reference term infant; FM and %FM were similar; BMM was greater. Corrected for weight, LM was similar to those of the reference infant, while the FM and %FM of study infants were slightly greater. CONCLUSIONS: DEXA accurately measures body mass. Body composition in preterm boys and girls differs. Interpretation of DEXA values may depend on whether age or body weight are regarded as the appropriate reference.