Effect of sex and prior exposure to a cafeteria diet on the distribution of sex hormones between plasma and blood cells

It is generally assumed that steroid hormones are carried in the blood free and/or bound to plasma proteins. We investigated whether blood cells were also able to bind/carry sex-related hormones: estrone, estradiol, DHEA and testosterone. Wistar male and female rats were fed a cafeteria diet for 30 days, which induced overweight. The rats were fed the standard rat diet for 15 additional days to minimize the immediate effects of excess ingested energy. Controls were always kept on standard diet. After the rats were killed, their blood was used for 1) measuring plasma hormone levels, 2) determining the binding of labeled hormones to washed red blood cells (RBC), 3) incubating whole blood with labeled hormones and determining the distribution of label between plasma and packed cells, discounting the trapped plasma volume, 4) determining free plasma hormone using labeled hormones, both through membrane ultrafiltration and dextrancharcoal removal. The results were computed individually for each rat. Cells retained up to 32% estrone, and down to 10% of testosterone, with marked differences due to sex and diet (the latter only for estrogens, not for DHEA and testosterone). Sex and diet also affected the concentrations of all hormones, with no significant diet effects for estradiol and DHEA, but with considerable interaction between both factors. Binding to RBC was non-specific for all hormones. Estrogen distribution in plasma compartments was affected by sex and diet. In conclusion: a) there is a large non-specific RBC-carried compartment for estrone, estradiol, DHEA and testosterone deeply affected by sex; b) Prior exposure to a cafeteria (hyperlipidic) diet induced hormone distribution changes, affected by sex, which hint at sex-related structural differences in RBC membranes; c) We postulate that the RBC compartment may contribute to maintain free (i.e., fully active) sex hormone levels in a way similar to plasma proteins non-specific binding.

The role of intramolecular barriers on the glass transition of polymers: computer simulations versus mode coupling theory

We present computer simulations of a simple bead-spring model for polymer melts with intramolecular barriers. By systematically tuning the strength of the barriers, we investigate their role on the glass transition. Dynamic observables are analyzed within the framework of the mode coupling theory (MCT). Critical nonergodicity parameters, critical temperatures, and dynamic exponents are obtained from consistent fits of simulation data to MCT asymptotic laws. The so-obtained MCT λ-exponent increases from standard values for fully flexible chains to values close to the upper limit for stiff chains. In analogy with systems exhibiting higher-order MCT transitions, we suggest that the observed large λ-values arise form the interplay between two distinct mechanisms for dynamic arrest: general packing effects and polymer-specific intramolecular barriers. We compare simulation results with numerical solutions of the MCT equations for polymer systems, within the polymer reference interaction site model (PRISM) for static correlations. We verify that the approximations introduced by the PRISM are fulfilled by simulations, with the same quality for all the range of investigated barrier strength. The numerical solutions reproduce the qualitative trends of simulations for the dependence of the nonergodicity parameters and critical temperatures on the barrier strength. In particular, the increase in the barrier strength at fixed density increases the localization length and the critical temperature. However the qualitative agreement between theory and simulation breaks in the limit of stiff chains. We discuss the possible origin of this feature.

Computer-aided system for morphometric mandibular index computation (Using dental panoramic radiographs)

Objective: We propose and validate a computer aided system to measure three different mandibular indexes: cortical width, panoramic mandibular index and, mandibular alveolar bone resorption index. Study Design: Repeatability and reproducibility of the measurements are analyzed and compared to the manual estimation of the same indexes. Results: The proposed computerized system exhibits superior repeatability and reproducibility rates compared to standard manual methods. Moreover, the time required to perform the measurements using the proposed method is negligible compared to perform the measurements manually. Conclusions: We have proposed a very user friendly computerized method to measure three different morphometric mandibular indexes. From the results we can conclude that the system provides a practical manner to perform these measurements. It does not require an expert examiner and does not take more than 16 seconds per analysis. Thus, it may be suitable to diagnose osteoporosis using dental panoramic radiographs

Do the interactions between glucocorticoids and sex hormones regulate the development of the metabolic syndrome?

The metabolic syndrome is basically a maturity-onset disease. Typically, its manifestations begin to flourish years after the initial dietary or environmental aggression began. Since most hormonal, metabolic, or defense responses are practically immediate, the procrastinated response do not seem justified. Only in childhood, the damages of the metabolic syndrome appear with minimal delay. Sex affects the incidence of the metabolic syndrome, but this is more an effect of timing than absolute gender differences, females holding better than males up to menopause, when the differences between sexes tend to disappear. The metabolic syndrome is related to an immune response, countered by a permanent increase in glucocorticoids, which keep the immune system at bay but also induce insulin resistance, alter the lipid metabolism, favor fat deposition, mobilize protein, and decrease androgen synthesis. Androgens limit the operation of glucocorticoids, which is also partly blocked by estrogens, since they decrease inflammation (which enhances glucocorticoid release). These facts suggest that the appearance of the metabolic syndrome symptoms depends on the strength (i.e., levels) of androgens and estrogens. The predominance of glucocorticoids and the full manifestation of the syndrome in men are favored by decreased androgen activity. Low androgens can be found in infancy, maturity, advanced age, or because of their inhibition by glucocorticoids (inflammation, stress, medical treatment). Estrogens decrease inflammation and reduce the glucocorticoid response. Low estrogen (infancy, menopause) again allow the predominance of glucocorticoids and the manifestation of the metabolic syndrome. It is postulated that the equilibrium between sex hormones and glucocorticoids may be a critical element in the timing of the manifestation of metabolic syndrome-related pathologies.

On the computation of reducible invariant tori on a parallel computer

We present an algorithm for the computation of reducible invariant tori of discrete dynamical systems that is suitable for tori of dimensions larger than 1. It is based on a quadratically convergent scheme that approximates, at the same time, the Fourier series of the torus, its Floquet transformation, and its Floquet matrix. The Floquet matrix describes the linearization of the dynamics around the torus and, hence, its linear stability. The algorithm presents a high degree of parallelism, and the computational effort grows linearly with the number of Fourier modes needed to represent the solution. For these reasons it is a very good option to compute quasi-periodic solutions with several basic frequencies. The paper includes some examples (flows) to show the efficiency of the method in a parallel computer. In these flows we compute invariant tori of dimensions up to 5, by taking suitable sections.

Sex Reversal in Zebrafish fancl Mutants is Caused by Tp53-Mediated Germ Cell Apoptosis

The molecular genetic mechanisms of sex determination are not known for most vertebrates, including zebrafish. We identified a mutation in the zebrafish fancl gene that causes homozygous mutants to develop as fertile males due to female-to-male sex reversal. Fancl is a member of the Fanconi Anemia/BRCA DNA repair pathway. Experiments showed that zebrafish fancl was expressed in developing germ cells in bipotential gonads at the critical time of sexual fate determination. Caspase-3 immunoassays revealed increased germ cell apoptosis in fancl mutants that compromised oocyte survival. In the absence of oocytes surviving through meiosis, somatic cells of mutant gonads did not maintain expression of the ovary gene cyp19a1a and did not down-regulate expression of the early testis gene amh; consequently, gonads masculinized and became testes. Remarkably, results showed that the introduction of a tp53 (p53) mutation into fancl mutants rescued the sex-reversal phenotype by reducing germ cell apoptosis and, thus, allowed fancl mutants to become fertile females. Our results show that Fancl function is not essential for spermatogonia and oogonia to become sperm or mature oocytes, but instead suggest that Fancl function is involved in the survival of developing oocytes through meiosis. This work reveals that Tp53-mediated germ cell apoptosis induces sex reversal after the mutation of a DNA-repair pathway gene by compromising the survival of oocytes and suggests the existence of an oocyte-derived signal that biases gonad fate towards the female developmental pathway and thereby controls zebrafish sex determination.

Validation of a computer-assisted system on classifying lower third molars

Objectives: The present study evaluates the reliability of the Radio Memory® software (Radio Memory; Belo Horizonte,Brasil.) on classifying lower third molars, analyzing intra- and interexaminer agreement of the results. Study Design: An observational, descriptive study of 280 lower third molars was made. The corresponding orthopantomographs were analyzed by two examiners using the Radio Memory® software. The exam was repeated 30 days after the first observation by each examiner. Both intra- and interexaminer agreement were determined using the SPSS v 12.0 software package for Windows (SPSS; Chicago, USA). Results: Intra- and interexaminer agreement was shown for both the Pell & Gregory and the Winter classifications, p<0.01, with 99% significant correlation between variables in all the cases. Conclusions: The use of Radio Memory® software for the classification of lower third molars is shown to be a valid alternative to the conventional method (direct evaluation on the orthopantomograph), for both clinical and investigational applications.

A Computer program for estimating population size by the removal method

A BASIC computer program (REMOVAL) was developed to compute in a VAXNMS environment all the calculations of the removal method for population size estimation (catch-effort method for closed populations with constant sampling effort). The program follows the maximum likelihood methodology,checks the failure conditions, applies the appropriate formula, and displays the estimates of population size and catchability, with their standard deviations and coefficients of variation, and two goodness-of-fit statistics with their significance levels. Data of removal experiments for the cyprinodontid fish Aphanius iberus in the Alt Emporda wetlands are used to exemplify the use of the program

Stable isotopes reveal trophic segregation by sex and age in the southern giant petrel in two different foodwebs

We investigated trophic ecology variation among colonies as well as sex- and age-related differences in the diet of the southern giant petrel Macronectes giganteus, a long-lived seabird that is sexually dimorphic in size. We measured stable isotopes (δ13C, δ15N) in blood samples collected during breeding at Bird Island (South Georgia, Antarctica) in 1998 and at 2 colonies in the Argentinean area of Patagonia in 2000 and 2001. Individuals from South Georgia showed lower δ13C and δ15N values than those in Patagonia, as expected from the more pelagic location and the short length of the Antarctic food web. Males and females showed significant differences in the isotopic signatures at both localities. These differences agree with the sexual differences in diet found in previous studies, which showed that both sexes rely mainly on penguin and seal carrion, but females also feed extensively on marine prey, such as fish, squid and crustaceans. However, males from Patagonia showed significantly higher δ15N and δ13C values than females did, and the reverse trend was observed at South Georgia. This opposite trend is probably related to the different trophic level of carrion between locations: whereas penguins and pinnipeds in Patagonia rely mainly on fish and cephalopods, in South Georgia they rely mainly on krill. Stable isotope values of male and female chicks in Patagonia did not differ; both attained high values, similar to adult males and higher than adult females, suggesting that parents do not provision their single offspring differently in relation to sex; however, they seem to provide offspring with a higher proportion of carrion, probably of higher quality, and more abundant food, than they consume themselves. Stable isotopes at South Georgia were not affected by age of adults. We have provided new information on intraspecific segregation in the diet in a seabird species and have also underlined the importance of considering food web structure when studying intraspecific variability in trophic ecology.

Parental body condition does not correlate with offspring sex-ratio in Cory's shearwater

We analyzed offspring sex ratio variation in Mediterranean Cory's Shearwater (Calonectris d. diomedea) during two consecutive breeding seasons in two colonies. We test for differential breeding conditions between years and colonies looking at several breeding parameters and parental condition. We then explored the relationship between offspring sex ratio and parental condition and breeding parameters. This species is sexually dimorphic with males larger and heavier than females; consequently we expected differential parental cost in rearing sexes, or a greater sensitivity of male chicks to adverse conditions, which may lead to biased sex ratios. Chicks were sexed molecularly by the amplification of the CHD genes. Offspring sex ratio did not differ from parity, either at hatching or fledging, regardless of the colony or year. However, parental body condition and breeding parameters such as egg size and breeding success were different between years and colonies. Nevertheless, neither nestling mortality nor body condition at fledging varied between years or colonies, suggesting that male and female chicks were probably not differentially affected by variability in breeding conditions.

Feather mercury levels in seabirds at South Georgia: Influences of trophic position, sex and age

We studied the mercury contamination of 13 species of seabirds breeding on Bird Island, South Georgia, in 1998. Total mercury concentrations in body feather samples of birds caught at their breeding colonies were determined. Among the species, grey-headed albatross (8933 ng g-1) and southern giant petrel (7774 ng g-1) showed the highest, and gentoo penguin (948 ng g-1) the lowest body feather mercury concentrations. Mercury levels were negatively correlated with the proportion of crustaceans (mainly krill) in the species¹ diets, suggesting that the trophic level is the most important factor in explaining the variation of mercury concentrations in Antarctic seabirds. In 4 species studied for age effects among adult birds (grey-headed and black-browed albatross, northern and southern giant petrel), no age-dependent variation in mercury levels was found. Sex differences were also assessed: female gentoo penguins had lower mercury levels than males, which may be related to the elimination of part of the mercury body burden by females into eggs. In contrast, northern giant petrel males had lower levels than females, which may be related to a higher consumption by males of carrion from Antarctic fur seals. In grey-headed albatrosses, mercury levels were 113% higher than in 1989, when this species was investigated at the same site, indicating a possible increase in mercury pollution of the Southern Ocean during the last decade.

Microcalcification evaluation in computer assisted diagnosis for digital mammography

In order to develop applications for z;isual interpretation of medical images, the early detection and evaluation of microcalcifications in digital mammograms is verg important since their presence is oftenassociated with a high incidence of breast cancers. Accurate classification into benign and malignant groups would help improve diagnostic sensitivity as well as reduce the number of unnecessa y biopsies. The challenge here is the selection of the useful features to distinguish benign from malignant micro calcifications. Our purpose in this work is to analyse a microcalcification evaluation method based on a set of shapebased features extracted from the digitised mammography. The segmentation of the microcalcificationsis performed using a fixed-tolerance region growing method to extract boundaries of calcifications with manually selected seed pixels. Taking into account that shapes and sizes of clustered microcalcificationshave been associated with a high risk of carcinoma based on digerent subjective measures, such as whether or not the calcifications are irregular, linear, vermiform, branched, rounded or ring like, our efforts were addressed to obtain a feature set related to the shape. The identification of the pammeters concerning the malignant character of the microcalcifications was performed on a set of 146 mammograms with their real diagnosis known in advance from biopsies. This allowed identifying the following shape-based parameters as the relevant ones: Number of clusters, Number of holes, Area, Feret elongation, Roughness, and Elongation. Further experiments on a set of 70 new mammogmms showed that the performance of the classification scheme is close to the mean performance of three expert radiologists, which allows to consider the proposed method for assisting the diagnosis and encourages to continue the investigation in the senseof adding new features not only related to the shape

Histological Study of the Sex-Change in the Skunk Clownfish Amphiprion akallopisos

Sex change in the protandrous fish Amphiprion akallopisos Bleeker, 1853 (F.Pomacentridae) has been analysed. Experiments consisted of placing males together after being separated from their mates, and observe changes in gonad histology at different periods, in order to identify signs of the sex change process. The presence of a first invagination on the male gonad wall, and the observation of the first cortical alveoli oocytes as an indication of the beginning of the vitellogenesis process, was the first symptom of the sex change, which has been detected after 18 days in one of the males. Period needed for the sex changing process was size independent. The process by which wall invagination is converted into ovarian lumen in the future mature ovary is also described

Computer-aided discovery of biological activity spectra for anti-aging and anti-cancer olive oil oleuropeins

Aging is associated with common conditions, including cancer, diabetes, cardiovascular disease, and Alzheimer"s disease. The type of multi‐targeted pharmacological approach necessary to address a complex multifaceted disease such as aging might take advantage of pleiotropic natural polyphenols affecting a wide variety of biological processes. We have recently postulated that the secoiridoids oleuropein aglycone (OA) and decarboxymethyl oleuropein aglycone (DOA), two complex polyphenols present in health‐promoting extra virgin olive oil (EVOO), might constitute a new family of plant‐produced gerosuppressant agents. This paper describes an analysis of the biological activity spectra (BAS) of OA and DOA using PASS (Prediction of Activity Spectra for Substances) software. PASS can predict thousands of biological activities, as the BAS of a compound is an intrinsic property that is largely dependent on the compound"s structure and reflects pharmacological effects, physiological and biochemical mechanisms of action, and specific toxicities. Using Pharmaexpert, a tool that analyzes the PASS‐predicted BAS of substances based on thousands of"mechanism‐ effect" and"effect‐mechanism" relationships, we illuminate hypothesis‐generating pharmacological effects, mechanisms of action, and targets that might underlie the anti‐aging/anti‐cancer activities of the gerosuppressant EVOO oleuropeins.