Incommensurate magnetic order in TbTe3

We report a neutron diffraction study of the magnetic phase transitions in the charge-density wave (CDW) TbTe(3) compound. We discover that in the paramagnetic phase there are strong 2D-like magnetic correlations, consistent with the pronounced anisotropy of the chemical structure. A long-range incommensurate magnetic order emerges in TbTe(3) at T(mag1) = 5.78 K as a result of continuous phase transitions. We observe that near the temperature T(mag1) the magnetic Bragg peaks appear around the position (0, 0, 0.24) (or its rational multiples), that is fairly close to the propagation vector (0,0,0.29) associated with the CDW phase transition in TbTe(3). This suggests that correlations leading to the long-range magnetic order in TbTe(3) are linked to the modulations that occur in the CDW state.

Cell differentiation and matrix organization in engineered teeth

Embryonic dental cells were used to check a series of criteria to be achieved for tooth engineering. Implantation of cultured cell-cell re-associations led to crown morphogenesis, epithelial histogenesis, organ vascularization, and root and periodontium development. The present work aimed to investigate the organization of predentin/dentin, enamel, and cementum which formed and mineralized after implantation. These implants were processed for histology, transmission electron microscopy, x-ray microanalysis, and electron diffraction. After two weeks of implantation, the re-associations showed gradients of differentiating odontoblasts. There were ciliated, polarized, and extended cell processes in predentin/dentin. Ameloblasts became functional. Enamel crystals showed a typical oriented arrangement in the inner and outer enamel. In the developing root, odontoblasts differentiated, cementogenesis occurred, and periodontal ligament fibroblasts interacted with the root surface and newly formed bone. The implantation of cultured dental cell re-associations allows for reproduction of complete functional differentiation at the cell, matrix, and mineral levels.

Oral health-related quality of life of elderly Germans--comparison of GOHAI and OHIP-14

OBJECTIVE

To obtain information about the subjective oral health status of non-clinical elderly populations of urban regions of Germany, one in the East and one in the West, by using OHIP-14 and, for first time, the GOHAI, and, furthermore, to compare the results obtained by use of both instruments.

BASIC RESEARCH DESIGN

Cross-sectional.

CLINICAL SETTING

Randomly chosen, non-clinical elderly population in urban regions of Germany.

PARTICIPANTS

197 participants (51% male) born in the years 1930-1932.

MAIN OUTCOME MEASURES

GOHAI, OHIP-14.

RESULTS

Median GOHAI score was 54; median OHIP-14 score was 2. Scores indicative of severely impaired oral health were rare. The effect of living in eastern or western Germany was of minor significance. Although the internal consistency of both measures was comparable and the same positive association with psychological wellbeing, absence of dry mouth, burning mouth, and removable dentures (p < 0.05) was observed, differences occurred. In simultaneous analysis of all items, factor analysis revealed only partial overlap of the items in extracted factors. Furthermore, the extreme score indicating no impairment was five times more frequent for OHIP-14. Of those who scored zero in OHIP-14, only 20% had the GOHAI equivalent score of 60, and for some GOHAI items the answer category for highest impairment was obtained.

CONCLUSIONS

GOHAI scores for this randomly chosen non-clinical group enable comparison with scores for Germany measured in the future. The differences between GOHAI and OHIP-14 make it necessary to select the most appropriate instrument for a planned purpose and study population.

Correlation between RhoB and Estrogen Receptor α (ERα) Expressions: From Experimental Data to Human Breast Tumors

Introduction: Hormonotherapy (HT) of breast cancers (BC) is strongly limitated by the resistances. Because Rho proteins are key elements in the cross-talks between ERα and growth factors signaling, they may be involved in the response to HT. RhoB could play a negative role in oncogenesis but there is no valid data regarding RhoB expression in BC. Experimental results: Our data suggest that RhoB participates in the balance of expression of ERα. The inhibition of the expression of RhoB using two sequences of interfering RNA in hormonodependent cell lines (MCF-7, T47D, ZR75) and in anti-estrogen resistant cell lines (LCC2, LCC9), decreases the expression of ERα both at the protein and mRNA levels. Moreover, in Mouse Embryonic Fibroblasts and uteri collected from RhoB knock-out mice, a dramatic decrease of ERα expression is observed. We therefore investigated the expression level of RhoB and ERα in BC tumors. Patients and methods: A tissue microarray (TMA) was constructed from a cohort of 113 patients (pts) enrolled in a randomized trial for adjuvant tamoxifen (median follow-up: 249.9 months). RhoB, ERα, and PR expressions were measured by immunochemistry. Cut-off used for ERα and PR + was 10% of stained cells. The expression of RhoB was calculated with the IRS score. Correlation of RhoB expression score with clinically diagnostic and prognostic variables was assessed using Man Whitney and Spearman's rank tests. Univariate survival analysis was performed for disease free survival (DFS) by applying the log-rank test to RhoB expression levels stratified by median value. TMA results: 65 (58.6%) were grade I-II; 74(66.1%) were ERα+ and 59(52.7%) PR+; 23 (22.1%) presented lymphovascular (LV) invasion. 39 pts (34.8%) had lymph nodes (LN) +. Pts under tamoxifen (n=62) had a less favorable pathological profile regarding + LN (p=0.0039), pathological tumour size (p=0.0486) and number of mitoses (p=0.0556). Age, ERα/PR status, histological grade or type and LV invasion status were similar in the two groups. We found less RhoB IRS expression in pts with tumor grade III (median 8 [1;12]) than in grade I-II (median 9 [3;12], p=0.0142). RhoB IRS expression was much higher in ERa + tumors (median:10.5 [3;12]) than in ERa negative tumors (median=8 [1;12], p=0.0023). RhoB IRS score was not correlated with the presence or not of LV invasion (p=0.26), neither with the presence of LN invasion (p= 0.74). Furthermore, RhoB expression is i) strongly correlated with the % of expression of ERα (Spearman'sρ=0.3659; p = 0.001) and PR (Spearman's ρ=0.2544 ; p=0.0076) ii) inversely correlated with histologic size (Spearman's ρ= -0.2344 ; p = 0.0166) and with number of mitose (Spearman's ρ=-0.2009 ; p=0.0362). The DFS of pts with ERα + tumors under tamoxifen or not was not affected by the level of RhoB expression. Conclusion: The analysis of 113 human breast tumors allowed to confirm experimental results, demonstrating that RhoB expression is strongly correlated with ERα expression. The role of RhoB as a potential suppressor gene of tumours in BC and its role in the response to HT have then to be investigated further.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5146.

Cancer testis antigen expression and immune responses by prostate cancer patients: Implications for prognosis and immunotherapy

e16101

Background: Prostate cancer (PC) is the most frequent malignancy in men and it continues to be one of the most common fatal cancers. Treatment options in advanced castration-resistant prostate cancer (CRPC) are limited. Cancer testis (CT) antigens are expressed in a variety of human cancers, but not in normal tissues except for MHC deficient spermatogonia, and represent promising targets for immunotherapy. Little is known about CT antigen expression in relation to disease progression. The aim of this study was to investigate which CT antigens are expressed and immunogenic and hence represent promising targets for patients with prostate cancer and correlate these findings with clinicopathological characteristics. Methods: To determine the expression of 6 CT antigens in prostate cancer immunohistochemistry was performed on tissue micro arrays. We investigated 6 CT antigens (NY-ESO.1, MAGE-C1, MAGE-C2, GAGE, MAGE-A1 and MAGE-A4) in benign hyperplasia (n=45), early (n=388) and late stage (n=71) prostate cancer. To determine the occurrence of spontaneous antibodies against cancer testis antigens, ELISA and Western blot was performed for NY-ESO-1, MAGE-C1 and MAGE-C2 with sera from prostate cancer patients. Results: CT antigens are increasingly expressed in late stage prostate cancers. As an exception we found MAGE-C2 to be expressed early in the course of disease, frequently inducing MAGE-C2 specific antibodies. In later stage metastatic prostate cancer patients NY-ESO-1 is more often expressed, inducing NY-ESO-1 specific antibodies. Conclusions: Cancer testis (CT) antigens are prognostic markers, frequently inducing immune responses and may be suitable for immunotherapeutic intervention in patients with prostate cancer.

No significant financial relationships to disclose.

Aflatoxigenic fungi and aflatoxin B1 in commercial pet food in Brazil

The aims of this study were to determine the aflatoxigenic mycoflora and the incidence of aflatoxin B1 in commercial samples of ready dog food. This in turn demonstrated the ability of the Aspergillus flavus and Aspergillus parasiticus strains to produce aflatoxin B1. 180 samples (standard, premium and super premium) were collected. Aspergillus was the prevalent genera followed by Penicillium and Fusarium. A. flavus and A. parasiticus were the prevalent species. All A. flavus and A. parasiticus strains from super premium samples were able to produce aflatoxin B1, whereas toxigenic strains isolated from standard and premium samples varied from 80 to 100%. A high percentage of ready pet food contaminated by toxigenic species from section Flavi was found and aflatoxin B1 levels were detected. The fungal counts from the three kinds of feed did not exceed the proposed value (1×104 cfu/g) and none of the samples exceeded the aflatoxin B1 recommended level (20 ng/g). The presence of A. flavus and A. parasiticus with aflatoxigenic ability could be a potential risk for production of AFB1 in feedstuffs when environmental storage conditions are not adequate.

Microscopic understanding of negative magnetization in Cu, Mn, and Fe based Prussian blue analogues

A crossover of the field-cooled magnetization from positive to negative has been observed below the magnetic ordering temperature (17.9 K) in a multimetal Prussian Blue analogue (PBA), Cu_{0.73}Mn_{0.77}[Fe(CN)_{6}].zH_{2}O. The reverse Monte Carlo (RMC) modeling (using the program RMCPOW) has been used to derive the various scattering contributions (e.g., nuclear diffuse, nuclear Bragg, magnetic diffuse, and magnetic Bragg) from the observed neutron diffraction patterns. The RMC analysis combined with the Rietveld refinement technique show an antiferromagnetic ordering of Mn moments with respect to the Cu as well as the Fe moments. Our study gives the first neutron magnetic structure evidence towards the microscopic understanding of the negative magnetization in the PBAs. This information can be effectively utilized to design suitable PBAs for making multifunctional devices.

Sex ratio conflict and worker production in eusocial hymenoptera

The best known of the conflicts occurring in eusocial Hymenoptera is queen-worker conflict over sex ratio. So far, sex ratio theory has mostly focused on optimal investment in the production of male versus female sexuals, neglecting the investment in workers. Increased investment in workers decreases immediate sexual productivity but increases expected future colony productivity. Thus, an important issue is to determine the queen's and workers' optimal investment in each of the three castes (workers, female sexuals, and male sexuals), taking into account a possible trade-off between production of female sexuals and workers (both castes developing from diploid female eggs). Here, we construct a simple and general kin selection model that allows us to calculate the evolutionarily stable investments in the three castes, while varying the identity of the party controlling resource allocation (relative investment in workers, female sexuals, and male sexuals). Our model shows that queens and workers favor the investment in workers that maximizes lifetime colony productivity of sexual males and females, whatever the colony kin structure. However, worker production is predicted to be at this optimum only if one of the two parties has complete control over resource allocation, a situation that is evolutionarily unstable because it strongly selects the other party to manipulate sex allocation in its favor. Queens are selected to force workers to raise all the males by limiting the number of eggs they lay, whereas workers should respond to egg limitation by raising a greater proportion of the female eggs into sexual females rather than workers as a means to attain a more female-biased sex allocation. This tug-of-war between queens and workers leads to a stable equilibrium where sex allocation is between the queen and worker optima and the investment in workers is below both parties' optimum. Our model further shows that, under most conditions, female larvae are in strong conflict with queens and workers over their developmental fate because they value their own reproduction more than that of siblings. With the help of our model, we also investigate how variation in queen number and number of matings per queen affect the level of conflict between queens, workers, and larvae and ultimately the allocation of resource in the three castes. Finally, we make predictions that allow us to test which party is in control of sex allocation and caste determination.

The evolution of cooperation and altruism--a general framework and a classification of models

One of the enduring puzzles in biology and the social sciences is the origin and persistence of intraspecific cooperation and altruism in humans and other species. Hundreds of theoretical models have been proposed and there is much confusion about the relationship between these models. To clarify the situation, we developed a synthetic conceptual framework that delineates the conditions necessary for the evolution of altruism and cooperation. We show that at least one of the four following conditions needs to be fulfilled: direct benefits to the focal individual performing a cooperative act; direct or indirect information allowing a better than random guess about whether a given individual will behave cooperatively in repeated reciprocal interactions; preferential interactions between related individuals; and genetic correlation between genes coding for altruism and phenotypic traits that can be identified. When one or more of these conditions are met, altruism or cooperation can evolve if the cost-to-benefit ratio of altruistic and cooperative acts is greater than a threshold value. The cost-to-benefit ratio can be altered by coercion, punishment and policing which therefore act as mechanisms facilitating the evolution of altruism and cooperation. All the models proposed so far are explicitly or implicitly built on these general principles, allowing us to classify them into four general categories.

Unicoloniality, recognition and genetic differentiation in a native Formica ant

Some ants have an extraordinary form of social organization, called unicoloniality, whereby individuals mix freely among physically separated nests. This mode of social organization has been primarily studied in introduced and invasive ant species, so that the recognition ability and genetic structure of ants forming unicolonial populations in their native range remain poorly known. We investigated the pattern of aggression and the genetic structure of six unicolonial populations of the ant Formica paralugubris at four hierarchical levels: within nests, among nests within the same population, among nests of populations within the Alps or Jura Mountains and among nests of the two mountain ranges. Ants within populations showed no aggressive behaviour, but recognized nonnestmates as shown by longer antennation bouts. Overall, the level of aggression increased with geographic and genetic distance but was always considerably lower than between species. No distinct behavioural supercolony boundaries were found. Our study provides evidence that unicoloniality can be maintained in noninvasive ants despite significant genetic differentiation and the ability to discriminate between nestmates and nonnestmates.

Genetic caste determination in Pogonomyrmex harvester ants imposes costs during colony founding

Some populations of Pogonomyrmex harvester ants comprise genetically differentiated pairs of interbreeding lineages. Queens mate with males of their own and of the alternate lineage and produce pure-lineage offspring which develop into queens and inter-lineage offspring which develop into workers. Here we tested whether such genetic caste determination is associated with costs in terms of the ability to optimally allocate resources to the production of queens and workers. During the stage of colony founding, when only workers are produced, queens laid a high proportion of pure-lineage eggs but the large majority of these eggs failed to develop. As a consequence, the number of offspring produced by incipient colonies decreased linearly with the proportion of pure-lineage eggs laid by queens. Moreover, queens of the lineage most commonly represented in a given mating flight produced more pure-lineage eggs, in line with the view that they mate randomly with the two types of males and indiscriminately use their sperm. Altogether these results predict frequency-dependent selection on pairs of lineages because queens of the more common lineage will produce more pure-lineage eggs and their colonies be less successful during the stage of colony founding, which may be an important force maintaining the coexistence of pairs of lineages within populations.

Spin dynamics and magnetic order in magnetically frustrated Tb2Sn2O7

We report a study of the geometrically frustrated magnetic material Tb2Sn2O7 by the positive muon-spin relaxation technique. No signature of a static magnetically ordered state is detected while neutron magnetic reflections are observed in agreement with a published report. This is explained by the dynamical nature of the ground state of Tb2Sn2O7: the Tb3+ magnetic moment characteristic fluctuation time is approximately 10(-10) s. The strong effect of the magnetic field on the muon-spin-lattice relaxation rate at low fields indicates a large field-induced increase of the magnetic density of states of the collective excitations at low energy.

Effect of inbreeding and heritability of sperm competition success in the bulb mite Rhizoglyphus robini

Sperm competition is a potent evolutionary force shaping the reproductive biology of most animal species. Here, we estimated the heritability of sperm competition success in the promiscuous bulb mite Rhizoglyphus robini. Sperm competition success was measured with the sterile male technique as the proportion of eggs fertilised by the second of three males mated with a single female. Sperm competition success responded significantly to selection. The heritability estimated from the response to five generations of selection was 0.13. We also estimated the effect of inbreeding on sperm competition success. Males produced by sib-mating (F=0.25) had a significantly lower sperm competition success than outbred males. The estimated coefficient of inbreeding depression was 0.53. Such high inbreeding depression together with moderately low heritability is consistent with the view that sperm competitive ability is under strong directional selection and strongly influences the reproductive success of males.