Determining the optimal interval for imaging surveillance of ascending aortic aneurysms

BackgroundCardiovascular guidelines recommend (bi-)annual computed tomography (CT) or magnetic resonance imaging (MRI) for surveillance of the diameter of thoracic aortic aneurysms (TAAs). However, no previous study has demonstrated the necessity for this approach. The current study aims to provide patient-specific intervals for imaging follow-up of non-syndromic TAAs.MethodsA total of 332 patients with non-syndromic ascending aortic aneurysms were followed over a median period of 6.7 years. Diameters were assessed using all available imaging techniques (echocardiography, CT and MRI). Growth rates were calculated from the differences between the first and last examinations. The diagnostic accuracy of follow-up protocols was calculated as the percentage of subjects requiring pre-emptive surgery in whom timely identification would have occurred.ResultsThe mean growth rate in our population was 0.2 ± 0.4 mm/year. The highest recorded growth rate was 2.0 mm/year, while 40.6% of patients showed no diameter expansion during follow-up. Females exhibited significantly higher growth rates than men (0.3 ± 0.5 vs 0.2 ± 0.4 mm/year, p = 0.007). Conversely, a bicuspid aortic valve was not associated with more rapid aortic growth. The optimal imaging protocol comprises triennial imaging of aneurysms 40–49 mm in diameter and yearly imaging of those measuring 50–54 mm. This strategy is as accurate as annual follow-up, but reduces the number of imaging examinations by 29.9%.ConclusionsIn our population of patients with non-syndromic TAAs, we found aneurysm growth rates to be lower than those previously reported. Yearly imaging does not lead to changes in the management of small aneurysms. Thus, lower imaging frequencies might be a good alternative approach.     

Olfactory sensitivity in tsetse flies: a daily rhythm

The diurnal tsetse Glossina morsitans morsitans bites especially in early morning and late afternoon; around midday feeding is at a low. In laboratory apparatus that measures the amount of locomotion under constant conditions over the photophase, the flies display a similar patterning of activity levels. The profile of daily rhythms for G. morsitans reported in the literature includes a number of motor and sensory motor systems that fluctuate cophasically. Lacking is a study on the patterning of the senses' response levels. In this paper we present the first instance of a daily modulation in the sense of smell. We stimulated the antennae with concentration series of host-derived odours and measured the spiking rate of cells at different times during the photophase. The concentration-response curves suggest that the sensitivity of antennal olfactory cells flows in parallel with the other daily rhythms. This was also reflected in electroantennograms (EAGs). The electroantennography was extended to G. fuscipes fuscipes, whose level of spontaneous locomotor activity--instead of following a U- shaped pattern--rises gradually over the photophase. Again, the EAGs appeared to parallel the species' locomotor activity. What we believe happens is that the organism tones down the sensitivity of its odour receptors during periods of anticipated inactivity for reasons of economy.      

Hot or not? Discovery and characterization of a thermostable alditol oxidase from Acidothermus cellulolyticus 11B

We describe the discovery, isolation and characterization of a highly thermostable alditol oxidase from Acidothermus cellulolyticus 11B. This protein was identified by searching the genomes of known thermophiles for enzymes homologous to Streptomyces coelicolor A3(2) alditol oxidase (AldO). A gene (sharing 48% protein sequence identity to AldO) was identified, cloned and expressed in Escherichia coli. Following 6xHis tag purification, characterization revealed the protein to be a covalent flavoprotein of 47?kDa with a remarkably similar reactivity and substrate specificity to that of AldO. A steady-state kinetic analysis with a number of different polyol substrates revealed lower catalytic rates but slightly altered substrate specificity when compared to AldO. Thermostability measurements revealed that the novel AldO is a highly thermostable enzyme with an unfolding temperature of 84?°C and an activity half-life at 75?°C of 112?min, prompting the name HotAldO. Inspired by earlier studies, we attempted a straightforward, exploratory approach to improve the thermostability of AldO by replacing residues with high B-factors with corresponding residues from HotAldO. None of these mutations resulted in a more thermostable oxidase; a fact that was corroborated by in silico analysis.     

Effect of environmental enrichment upon resource holding power in fish in prior residence situations

Resource holding power (RHP), as expressed by gaining dominance, can be affected by extrinsic and intrinsic factors. Extrinsic factors that increase the RHP include e.g. prior exposure to the contest area. The pay-off asymmetry hypothesis was tested according to which there is an asymmetry in the value the resident's territory has for the resident and intruders, i.e. the resident loses more than intruder opponents when losing the contest over a territory in which it has invested much energy during the exploration of food and shelter resources, during the settlement of conflicts with territorial neighbours, etc. This asymmetry will increase the resident's chance to win the fight over intruders. If the resident-intruder asymmetry is enhanced by presenting resource-rich territories to e.g. fish (structurally diverse or 'rich' aquariums), the hypothesis predicts that the resident's dominance chance (probability to win the fight) will be higher than in structurally 'poor' aquariums. It was found that residents were proportionately more often dominant (fight winners) than intruders in the rich compared to the poor aquariums in all seven tested fish species. This demonstrates that a high territory resource value (aquarium enrichment) significantly facilitates the expression of the resident's dominance advantage (prior residence effect). In contrast to dominance, aggressive behaviour before the dominance settlement did not generally differ between residents and intruders when compared in rich and poor aquariums. This suggests that dominance in itself and aggression prior to dominance settlement are at least partially guided by different motivational systems.     

The Effect of Submissive Experiences on Dominance and Aggressive Behaviour of Xiphophorus (Pisces,Poeciliidae)

• 1 Aus einer Gruppe junger Xiphophorus-Hybriden (X. helleri × X. maculatus) wurden 20 Fischpaare an aufeinanderfolgenden Tagen ausgewählt, so daß jedes Paar während eines Tages untersucht werden konnte. Die zwei Fische jeden Paares wurden zuerst für 45 Min. zusammengesetzt, um den dominierenden α-Fisch und den untergeordneten Ω-Fisch zu bestimmen. Nur in 15 Paaren entschied sich die Dominanz innerhalb dieses Zeitraums, bei sieben innerhalb 30 Min., wenn sie gefüttert wurden. Alle bildeten stabile Dominanzverhältnisse ohne Umkehrungen, außer in einem ziemlich zweifelhaften Falle.
• 2 Darauf wurden die α-Fische aus 8 Paaren (experimentellen Paaren) je zu einem größeren Fisch gesetzt, von dem sie einen ganzen Tag lang beherrscht wurden; die α-Tiere der 7 anderen Paare kamen (Kontrollpaare) zu einem kleineren, der ihnen niemals überlegen war. (Täglich entschied das Los, ob ein Paar eine experimentelle (E) oder eine Kontroll-(C) Behandlung bekommen sollte, so daß die 8 E- und 7 C-Paare statistisch äquivalent waren.) Die 5 übrigen Paare wurden nicht weiter für das Experiment gebraucht. Nach einem Tag wurden die α-Fische wieder ins selbe Aquarium gesetzt wie zuerst, zusammen mit ihren α-Partnern, die inzwischen in einem anderen Aquarium isoliert gewesen waren. Der einzige statistisch gesicherte Effekt war, daß die früheren Ω-Fische nach einer schweren E-Behandlung ihrer α-Partner in signifikant mehr Fällen anzugreifen begannen als nach einer C-Behandlung der α-Partner.
• 3 Andere Experimente über den Einfluß von Subordinationserfahrungen auf die Dominanz werden besprochen. Die Ergebnisse werden nach einer Hypothese interpretiert, die wechselseitige positive Einflüsse zwischen dem Flucht- und dem Angriffsverhalten annimmt und die den meisten Dominanzverhältnissen in Tiergruppen zugrunde liegen kann.

     

Biochemical pathways analysis of microarray results: regulation of myogenesis in pigs

Background  

Combining microarray results and biological pathway information will add insight into biological processes. Pathway information is widely available in databases through the internet.     

Mitral prolapsing volume is associated with increased cardiac dimensions in patients with mitral annular disjunction

Netherlands Heart Journal - In patients with mitral annular disjunction (MAD), it can be difficult to assess the severity of mitral regurgitation (MR), as they present with a prolapsing...     

Major morphological effects of a regulatory gene: Pgm1-t in rainbow trout

We have investigated the morphological effects of a genetic locus, Pgm1- t, that affects the expression of a phosphoglucomutase locus (Pgm1) in liver of rainbow trout (Salmo gairdneri). We have previously shown that embryos with liver Pgm1 expression hatch earlier than those without liver Pgm1 expression. We predicted that this difference in developmental rate should cause a reduction in meristic counts in the more rapidly developing fish with liver Pgm1 expression. Eight meristic (countable) characters in nine full-sib groups segregating for the presence or absence of liver Pgm1 expression are in agreement with this prediction. In eight of the nine families, there is a significant difference in the multivariate distribution of the eight meristic counts between full sibs with and without liver Pgm1 expression. This separation in multivariate space is based on a tendency for lower meristic counts in fish with liver Pgm1 expression. The magnitude of these morphological differences is similar to that between two subspecies of cutthroat trout (Salmo clarki) that show substantial genetic divergence at structural loci encoding enzymes (Nei's D = 0.34). These data support the view that small changes in the developmental process caused by genetic differences at regulatory genes can have large effects on morphology.