Accuracy of experimental mandibular osteotomy using the image-guided sagittal saw.

The aim of this study was to perform an objective assessment of the accuracy of mandibular osteotomy simulations performed using an image-guided sagittal saw. A total of 16 image-guided mandibular osteotomies were performed on four prefabricated anatomical models according to the virtual plan. Postoperative computed tomography (CT) image data were fused with the preoperative CT scan allowing an objective comparison of the results of the osteotomy executed with the virtual plan. For each operation, the following parameters were analyzed and compared independently twice by two observers: resected bone volume, osteotomy trajectory angle, and marginal point positions. The mean target registration error was 0.95±0.19mm. For all osteotomies performed, the mean difference between the planned and actual bone resection volumes was 8.55±5.51%, the mean angular deviation between planned and actual osteotomy trajectory was 8.08±5.50°, and the mean difference between the preoperative and the postoperative marginal point positions was 2.63±1.27mm. In conclusion, despite the initial stages of the research, encouraging results were obtained. The current limitations of the navigated saw are discussed, as well as the improvements in technology that should increase its predictability and efficiency, making it a reliable method for improving the surgical outcomes of maxillofacial operations.

Replicated evolutionary divergence in the cuticular hydrocarbon profile of male crickets associated with the loss of song in the Hawaiian archipelago.

Female choice based on male secondary sexual traits is well documented, although the extent to which this selection can drive an evolutionary divergence in male traits among populations is less clear. Male field crickets Teleogryllus oceanicus attract females using a calling song and once contacted switch to courtship song to persuade them to mate. These crickets also secrete onto their cuticle a cocktail of long-chained fatty acids or cuticular hydrocarbons (CHCs). Females choose among potential mates based on the structure of male acoustic signals and on the composition of male CHC profiles. Here, we utilize two naturally occurring mutations that have arisen independently on two Hawaiian islands and render the male silent to ask whether the evolutionary loss of acoustic signalling can drive an evolutionary divergence in the alternative signalling modality, male CHC profiles. QST -FST comparisons revealed strong patterns of CHC divergence among three populations of crickets on the islands of Hawaii, Oahu and Kauai. Contrasts between wild-type and flatwing males on the islands of Oahu and Kauai indicated that variation in male CHC profiles within populations is associated with the loss of acoustic signalling; flatwing males had a relatively low abundance of long-chained CHCs relative to the short-chained CHCs that females find attractive. Given their dual functions in desiccation resistance and sexual signalling, insect CHCs may be particularly important traits for reproductive isolation and ultimately speciation.

Island hopping introduces Polynesian field crickets to novel environments, genetic bottlenecks and rapid evolution.

Teleogryllus oceanicus, a cricket native to Australia, was introduced to Hawaii where it encounters a novel natural enemy responsible for their recent rapid evolutionary loss of singing ability. To explore how genetic diversity varies across their broad range, their mode of introduction to Hawaii and nonadaptive influences on the sexual signalling system, we assessed variation at seven microsatellite loci in 19 Australian and island populations. Genetic variability was highest in Australia, intermediate in Oceania and lowest in Hawaii, and differentiation among local populations was a clear function of geographical distance. Hawaiian populations are most closely related to those from the Society Islands and Cook Islands, and a neighbour-joining tree based on D(A) is consistent with movement by Polynesian settlers. We found evidence of bottlenecks in six island populations (including three Hawaiian populations), supporting previous findings in which bottlenecks were implicated in the crickets' loss of singing ability.

IR and Raman studies of oil and seedcake extracts from natural and genetically modified flax seeds.

Flax plant of the third generation (F3) overexpressing key genes of flavonoid pathway cultivated in field in 2008 season was used as the plant material throughout this study. The biochemical properties of seed, oil and seedcake extracts from natural and transgenic flax plants were compared. Overproduction of flavonoids (kaempferol), phenolic acids (coumaric, ferulic/synapic) and lignan-secoisolariciresinol diglucoside (SDG) in oil and extracts from transgenic seeds has been revealed providing a valuable source of these compounds for biotechnological application. The changes in fatty acids composition and increase in their stability against oxidation along three plant generations were also detected. The analysis of oil and seedcake extracts was performed using Raman and IR spectroscopy. The wavenumbers and integral intensities of Raman and IR bands were used to identify the components of phenylpropanoid pathway in oil and seedcake extracts from control and transgenic flax seeds. The spectroscopic data were compared to those obtained from biochemical analysis.

The effect of Linola and W92/72 transgenic flax seeds on the rabbit caecal fermentation--in vitro study.

The effect of W92/72 transgenic flax seeds taken from a variety of Linola on the production of SCFA, ammonia and methane by bacteria inhabiting rabbit caecum was studied. The in vitro method was used where caecal contents from rabbits was incubated with W92/72 transgenic or Linola flax seeds, or without any additives (control samples). The total concentration of SCFA was higher in samples with the addition of flax seeds than in the control samples. The increase in concentrations of acetic, propionic and butyric acids was the highest in samples with Linola seeds added. A higher percentage of propionic and butyric acids was observed in the contents incubated with addition of flax seeds as compared to the control samples. This increase was the result of a percentage decrease in acetic acid. No differences were observed in the concentration of ammonia between fermented samples. Moreover, the addition of flax seeds resulted in slight decrease of pH in incubated samples. In gas samples, the methane level was higher in samples with flax seeds added, although the highest level was found in samples with transgenic seeds. In addition, gas pressure was significantly higher in samples with flax seeds added as compared to control samples, and this may indicate a higher intensity of microbiological fermentation processes. These studies suggest that neither Linola nor W92/72 flax seeds have any unfavorable effect on the caecal microflora activity of rabbits. A beneficial influence of flax seeds on the microbiological fermentation process in rabbit caecum was observed, based on an increase in percentage ratio of propionic acid in samples with flax seeds added.

Does signalling mitigate the cost of agonistic interactions? A test in a cricket that has lost its song.

Prevailing models of animal communication assume that signalling during aggressive conflict mitigates the costs of fighting. We tested this assumption by staging dyadic encounters between male field crickets, Teleogryllus oceanicus, under three conditions: (i) both males could sing aggressive songs, (ii) neither male could sing, and (iii) one male could sing but the other could not. We conducted experiments on males from a Hawaiian population from Kauai that has recently evolved signal loss, and males from a Hawaiian population from the Big Island that has not. Among both populations, interactions between two silent males were characterized by higher levels of aggression than interactions involving one or two singing males. Because the level of aggression is strongly related to the cost of fighting, these data demonstrate that signalling mitigates the cost of fighting. In mixed trials, we found no statistically significant differences between the behaviour of calling and non-calling males in either population. We conclude that there is no evidence that the Kauai population exhibits special adaptations to alleviate the costs of signal loss. Finally, we found that males were much more likely to signal after their opponent's retreat than after their own retreat. Aggressive song therefore meets the definition of a 'victory display'.

Molecular characterization of Polish patients with familial hypercholesterolemia: novel and recurrent LDLR mutations.

Autosomal dominant hypercholesterolemia (ADH) is caused by mutations in the genes coding for the low-density lipoprotein receptor (LDLR), apolipoprotein B-100 (APOB), or proprotein convertase subtilisin/kexin type 9 (PCSK9). In this study, a molecular analysis of LDLR and APOB was performed in a group of 378 unrelated ADH patients, to explore the mutation spectrum that causes hypercholesterolemia in Poland. All patients were clinically diagnosed with ADH according to a uniform protocol and internationally accepted WHO criteria. Mutational analysis included all exons, exon-intron boundaries and the promoter sequence of the LDLR, and a fragment of exon 26 of APOB. Additionally, the MLPA technique was applied to detect rearrangements within LDLR. In total, 100 sequence variations were identified in 234 (62%) patients. Within LDLR, 40 novel and 59 previously described sequence variations were detected. Of the 99 LDLR sequence variations, 71 may be pathogenic mutations. The most frequent LDLR alteration was a point mutation p.G592E detected in 38 (10%) patients, followed by duplication of exons 4-8 found in 16 individuals (4.2%). Twenty-five cases (6.6%) demonstrated the p.R3527Q mutation of APOB. Our findings imply that major rearrangements of the LDLR gene as well as 2 point mutations (p.G592E in LDLR and p.R3527Q in APOB) are frequent causes of ADH in Poland. However, the heterogeneity of LDLR mutations detected in the studied group confirms the requirement for complex molecular studies of Polish ADH patients.

Sex differences in metabolic rates in field crickets and their dipteran parasitoids.

Sex differences in metabolic rate (MR) can result from dimorphism in the performance of energetically demanding activities. Male crickets (Teleogryllus oceanicus) engage in costly calling and aggressive activity not performed by females. Consistent with this difference, we found higher maximal MR, factorial scope, and fat content in males than females. T. oceanicus song is also costly because it attracts the parasitoid fly Ormia ochracea. Parasitized crickets had reduced maximal MR consistent with a metabolic cost to harboring larvae. This cost was greater for females, either because females invest more heavily into reproduction at the expense of metabolic capacity, or because males are under stronger selection to respond to infection. Little is known about O. ochracea outside of its auditory system and parasitic lifestyle. We observed greater resting MR in male flies, possibly reflecting a sex difference in the requirement for metabolic power output, because male flies perform potentially costly mating behavior not seen in females. We found a positive relationship between larval density within a cricket and pupal resting MR, suggesting that crickets in good condition are able to both harbor more larvae and produce larvae with higher resting MR. These results reveal a complex interplay between the metabolism of crickets and their fly parasitoids.

Geographic variation in female preference functions and male songs of the field cricket Teleogryllus oceanicus.

Male crickets (Teleogryllus oceanicus) produce a complex call consisting of two elements, the long chirp (three to eight sound pulses) followed by a series of short chirps (each with two sound pulses). There is significant geographic variation in the temporal structure of calls, and the long chirp is selected against by acoustically orienting parasitoids in some populations. Here we examine geographic variation in female preference functions for the amount of long chirp. In general, females prefer calls with greater proportions of long chirp, although the strength and nature of selection varied across populations. Variation in preference functions did not match variation in call structure. There was a mismatch between the proportion of long chirp produced by males in a population and the proportion of long chirp preferred by females. The convergent preferences of predators and females are likely to maintain genetic variation in song traits in parasitized populations. The apparent mismatch between preference and trait is discussed in relation to theoretical models of preference evolution.

Chemical analysis of diesel engine nanoparticles using a nano-DMA/thermal desorption particle beam mass spectrometer.

Diesel engines are known to emit high number concentrations of nanoparticles (diameter < 50 nm), but the physical and chemical mechanisms by which they form are not understood. Information on chemical composition is lacking because the small size, low mass concentration, and potential for contamination of samples obtained by standard techniques make nanoparticles difficult to analyze. A nano-differential mobility analyzer was used to size-select nanoparticles (mass median diameter approximately 25-60 nm) from diesel engine exhaust for subsequent chemical analysis by thermal desorption particle beam mass spectrometry. Mass spectra were used to identify and quantify nanoparticle components, and compound molecular weights and vapor pressures were estimated from calibrated desorption temperatures. Branched alkanes and alkyl-substituted cycloalkanes from unburned fuel and/or lubricating oil appear to contribute most of the diesel nanoparticle mass. The volatility of the organic fraction of the aerosol increases as the engine load decreases and as particle size increases. Sulfuric acid was also detected at estimated concentrations of a few percent of the total nanoparticle mass. The results are consistent with a mechanism of nanoparticle formation involving nucleation of sulfuric acid and water, followed by particle growth by condensation of organic species.

Sexual selection and speciation.

The power of sexual selection to drive changes in mate recognition traits gives it the potential to be a potent force in speciation. Much of the evidence to support this possibility comes from comparative studies that examine differences in the number of species between clades that apparently differ in the intensity of sexual selection. We argue that more detailed studies are needed, examining extinction rates and other sources of variation in species richness. Typically, investigations of extant natural populations have been too indirect to convincingly conclude speciation by sexual selection. Recent empirical work, however, is beginning to take a more direct approach and rule out confounding variables.

The effects of age and previous experience on social rank in female red junglefowl, Gallus gallus spadiceus.

Social rank can influence lifetime reproductive success and therefore fitness. We examined the effects of morphology, age, previous social experience and aggressiveness on social rank in all-female flocks of red junglefowl. None of the morphological characters measured (mass, tarsus length, comb height or comb length) appeared to play a role in determining rank. Older females were not more likely to be dominant, while previous social experience and aggression levels were both important in dominance determination. Flock-experienced hens were more likely to be dominant as were more aggressive individuals. Red junglefowl females most likely use a combination of characters to establish social order in a newly formed flock. Copyright 2000 The Association for the Study of Animal Behaviour.

Venereal worms: sexually transmitted nematodes in the decorated cricket.

The nematode, Mehdinema alii, occurs in the alimentary canal of the decorated cricket Gryllodes sigillatus. Adult nematodes occur primarily in the hindgut of mature male crickets, whereas juvenile nematodes are found in the genital chambers of mature male and female crickets. Here, we present experimental evidence for the venereal transmission of M. alii in G. sigillatus. Infectivity experiments were conducted to test for transmission via oral-fecal contamination, same-sex contact, and copulation. The infective dauers of the nematode are transferred from male to female crickets during copulation. Adult female crickets harboring infective dauers subsequently transfer the nematode to their next mates. Thus, M. alii is transmitted sexually during copulation.

Photochemical decontamination of red blood cell concentrates with the silicon phthalocyanine PC 4 and red light.

Various approaches are being developed for virus inactivation of red blood cell concentrates (RBCC) in order to increase the safety of the blood supply. We have been studying the silicon phthalocyanine Pc 4 for this purpose, a photosensitizer activated with red light. Pc 4 targets the envelope of pathogenic viruses such as HIV. To protect RBC during the process two main approaches are used: (i) inclusion of quenchers of reactive oxygen species produced during the treatment. Tocopherol succinate was found to be most effective for this purpose; (ii) formulation of Pc 4, a lipophilic compound, in liposomes that reduce its binding to RBC but not to viruses. As a light source we used a light emitting diode array emitting at 670-680 nm. An efficient mixing device ensures homogenous light exposure during treatment of intact RBCC. Treatment of 50 ml RBCC with 5 microM Pc 4 and 18 J/cm(2) light results in the inactivation of > or = 5.5 log(10) HIV, > or = 6.3 log(10), VSV and > or = 5 log(10) of PRV and BVDV. The relative sensitivities of these viruses based on the slope of virus kill versus light dose are 1.0, 1.25, 1.5 and 1.9 for HIV, VSV, PRV and BVDV, respectively. To achieve the same level of virus inactivation in 350 ml RBCC, the light dose needed is 40 J/cm(2). HIV actively replicating in CEM cells is as sensitive as cell-free and HIV in latently infected cells is 3-4 times more sensitive. Parasites that can be transmitted by blood transfusion (P. falciparum and T. cruzi) are even more sensitive than viruses. Following treatment, RBCC can be stored for 28 days at 4 degrees C with haemolysis below 1%. Previous studies under less favourable conditions showed that baboon RBC circulated with an acceptable 24 hr recovery and half-life. Genetic toxicological studies of Pc 4 with or without light exposure (mutagenicity in bacteria, mammalian cells in vitro and clastogenicity in vivo) were negative. We conclude that a process using Pc 4 and red light can potentially reduce the risk of transmitting pathogens in RBCC.

Photochemical decontamination of red cell concentrates with the silicon phthalocyanine pc 4 and red light.

Virus inactivation in red blood cell concentrates (RBCC) is being studied in order to increase the safety of the blood supply. For this purpose we have been studying the silicon phthalocyanine (Pc 4), a photosensitizer activated with red light. Two approaches were used to achieve enhanced selectivity of Pc 4 for virus inactivation. One was formulation of Pc 4 in liposomes that reduce its binding to red cells. The other was the use of a light emitting diode (LED) array emitting at 700 nm. Vesicular stomatitis virus (VSV) infectivity served as an endpoint for virus kill in treated RBCC. Red cell hemolysis and circulatory survival in rabbits served as measures for red cell damage. Treatment of small aliquots of human RBCC with 2 µM Pc 4 in liposomes and 10 J/cm2 of 700 nm LED light in the presence of the quenchers of reactive oxygen species glutathione and trolox resulted in 6 log10 inactivation of VSV. Under these conditions hemolysis of treated red cells stored at 4 °C for 21 days was only slightly above that of control cells. Rabbit RBCC similarly treated circulated with a half life of 7.5 days compared with 10.5 days of control. It is concluded that Pc 4 used as described here may be useful for viral decontamination of RBCC, pending toxicological and clinical studies. © 1999 Society of Photo-Optical Instrumentation Engineers.

Parasites influence social rank and morphology, but not mate choice, in female red junglefowl, Gallus gallus.

Parasites can profoundly affect host morphology and behaviour, but previous work has focused on the effects of parasites on males. In the present study, we assessed the effects of infection with the nematode Ascaridia galli on the morphology and behaviour, including mate choice, of female red junglefowl. Hens infected with A. galli had lower mass and smaller combs than unparasitized birds when sexually mature. Parasite status had a significant effect on social rank in all-female flocks, with high-ranking birds being less likely to be parasitized. Larger females had higher social rank, but comb size was unrelated to social status. Neither parasite status nor social rank had any effect on mate choice. These results differ from those found for male red junglefowl, and suggest that males and females may allocate resources differently to comb versus growth. The low cost of choice in the red junglefowl mating system may also contribute to the lack of an effect of parasites and social status on mate choice Copyright 1998 The Association for the Study of Animal Behaviour

Sex differences in parasite infections: patterns and processes.

Sex differences in parasite infection rates, intensities, or population patterns are common in a wide range of taxa. These differences are usually attributed to 1 of 2 causes: (1) ecological (sociological in humans); and (2) physiological, usually hormonal in origin. Examples of the first cause include differential exposure to pathogens because of sex-specific behavior or morphology. The second cause may stem from the well-documented association between testosterone and the immune system; sexually mature male vertebrates are often more susceptible to infection and carry higher parasite burdens in the field. Although many researchers favor one explanation over the other, the requisite controlled experiments to rule out confounding variables are often neglected. We suggest that sex differences in disease have evolved just as sex differences in morphology and behavior, and are the result of selection acting differently on males and females. Research has often focused on proximate mechanistic explanations for the sex difference in infection rates, but it is equally important to understand the generality of the patterns in an evolutionary context. Because males potentially gain more than females by taking risks and engaging in competition, sexual selection pressure has shaped male behavior and appearance to maximize competitive ability and attractiveness. Many of the classic male attributes such as antlers on deer are testosterone-dependent, putting males in what appears to be a cruel bind: become vulnerable to disease by developing an attractive secondary sexual ornament, or risk lowered mating success by reducing it. A variety of hypotheses have been put forward to explain why males have not circumvented this dilemma. The mating system of the host species will influence the likelihood of sex differences in parasite infection, because males in monogamous species are subject to weaker sexual selection than males in polygynous species. Whether these evolutionary generalizations apply to invertebrates, which lack testosterone, remains to be seen.