Human genetic studies in areas of high natural radiation. VIII. Genetic load not related to radiation.

The genetic load disclosed by inbreeding has been analyzed in a multiple regression model for a population involving several localities in the state of Espírito Santo, Brazil. The inbreeding load has been estimated for number of pregnancies, abortions, stillbirths, children born alive, anomalies in general, sex ratio, infant mortality, post-infant mortality, and sterility and infertility of the couple. There was no evidence of either maternal or paternal inbreeding effects on the variables analyzed. The effect of inbreeding of the zygote was significant only for anomalies in general (B = 2.29 +/- 0.45) and infant mortality (B = 3.19 +/- 1.39). The latter result must be accepted with caution because of the many environmental causes affecting infant mortality. The B/A ratio suggested a predominantly mutational load for anomalies in general (B/A = 25), but with respect to infant mortality (B/A = 6), the ratio is regarded as an underestimate because of the environmental contribution to A and therefore not supportive of the segregational interpretation.     

L value determination under paddy soil condition

Summary The L values of four paddy soils and one United Kingdom soil were determined under water-logged and aerobic conditions over a period of 7 weeks using rice and ryegrass as the respective test crops.Under water-logged conditions, the L values attained a constant level in the course of the growing period, indicating that isotopic equilibrium between the added P³² and the soil was achieved.Under aerobic conditions, the equilibrium L values tended to be lower than those determined under water-logged conditions.This was taken as an indication of an increase of labile soil phosphorus by reduction of ferric iron.     

Development of a New Approach to Aid in Visual Identification of Murine iPS Colonies Using a Fuzzy Logic Decision Support System

The a priori identification of induced pluripotent stem cells remains a challenge. Being able to quickly identify the most embryonic stem cell-similar induced pluripotent stem cells when validating results could help to reduce costs and save time. In this context, tools based on non-classic logic can be useful in creating aid-systems based on visual criteria. True colonies when viewed at 100x magnification have been found to have the following 3 characteristics: a high degree of border delineation, a more uniform texture, and the absence of a cracked texture. These visual criteria were used for fuzzy logic modeling. We investigated the possibility of predicting the presence of alkaline phosphatase activity, typical of true induced pluripotent stem cell colonies, after 25 individuals, with varying degrees of experience in working with murine iPS cells, categorized the images of 136 colonies based on visual criteria. Intriguingly, the performance evaluation by area under the ROC curve (16 individuals with satisfactory performance), Spearman correlation (all statistically significant), and Cohen''s Kappa agreement analysis (all statistically significant) demonstrates that the discriminatory capacity of different evaluators are similar, even those who have never cultivated cells. Thus, we report on a new system to facilitate visual identification of murine- induced pluripotent stem cell colonies that can be useful for staff training and opens the possibility of exploring visual characteristics of induced pluripotent stem cell colonies with their functional peculiarities. The fuzzy model has been integrated as a web-based tool named “2see-iPS” which is freely accessed at http://genetica.incor.usp.br/2seeips/.     

Trypanosoma cruzi Response to Sterol Biosynthesis Inhibitors: Morphophysiological Alterations Leading to Cell Death

The protozoan parasite Trypanosoma cruzi displays similarities to fungi in terms of its sterol lipid biosynthesis, as ergosterol and other 24-alkylated sterols are its principal endogenous sterols. The sterol pathway is thus a potential drug target for the treatment of Chagas disease. We describe here a comparative study of the growth inhibition, ultrastructural and physiological changes leading to the death of T. cruzi cells following treatment with the sterol biosynthesis inhibitors (SBIs) ketoconazole and lovastatin. We first calculated the drug concentration inhibiting epimastigote growth by 50% (EC₅₀/72 h) or killing all cells within 24 hours (EC₁₀₀/24 h). Incubation with inhibitors at the EC₅₀/72 h resulted in interesting morphological changes: intense proliferation of the inner mitochondrial membrane, which was corroborated by flow cytometry and confocal microscopy of the parasites stained with rhodamine 123, and strong swelling of the reservosomes, which was confirmed by acridine orange staining. These changes to the mitochondria and reservosomes may reflect the involvement of these organelles in ergosterol biosynthesis or the progressive autophagic process culminating in cell lysis after 6 to 7 days of treatment with SBIs at the EC₅₀/72 h. By contrast, treatment with SBIs at the EC₁₀₀/24 h resulted in rapid cell death with a necrotic phenotype: time-dependent cytosolic calcium overload, mitochondrial depolarization and reservosome membrane permeabilization (RMP), culminating in cell lysis after a few hours of drug exposure. We provide the first demonstration that RMP constitutes the “point of no return” in the cell death cascade, and propose a model for the necrotic cell death of T. cruzi. Thus, SBIs trigger cell death by different mechanisms, depending on the dose used, in T. cruzi. These findings shed new light on ergosterol biosynthesis and the mechanisms of programmed cell death in this ancient protozoan parasite.     

Racial Discrimination & Cardiovascular Disease Risk: My Body My Story Study of 1005 US-Born Black and White Community Health Center Participants (US)

Objectives

To date, limited and inconsistent evidence exists regarding racial discrimination and risk of cardiovascular disease (CVD).

Methods

Cross-sectional observational study of 1005 US-born non-Hispanic black (n = 504) and white (n = 501) participants age 35–64 randomly selected from community health centers in Boston, MA (2008–2010; 82.4% response rate), using 3 racial discrimination measures: explicit self-report; implicit association test (IAT, a time reaction test for self and group as target vs. perpetrator of discrimination); and structural (Jim Crow status of state of birth, i.e. legal racial discrimination prior 1964).

Results

Black and white participants both had adverse cardiovascular and socioeconomic profiles, with black participants most highly exposed to racial discrimination. Positive crude associations among black participants occurred for Jim Crow birthplace and hypertension (odds ratio (OR) 1.92, 95% confidence interval (CI) 1.28, 2.89) and for explicit self-report and the Framingham 10 year CVD risk score (beta  = 0.04; 95% CI 0.01, 0.07); among white participants, only negative crude associations existed (for IAT for self, for lower systolic blood pressure (SBP; beta  = −4.86; 95% CI −9.08, −0.64) and lower Framingham CVD score (beta  = −0.36, 95% CI −0.63, −0.08)). All of these associations were attenuated and all but the white IAT-Framingham risk score association were rendered null in analyses that controlled for lifetime socioeconomic position and additional covariates. Controlling for racial discrimination, socioeconomic position, and other covariates did not attenuate the crude black excess risk for SBP and hypertension and left unaffected the null excess risk for the Framingham CVD score.

Conclusion

Despite worse exposures among the black participants, racial discrimination and socioeconomic position were not associated, in multivariable analyses, with risk of CVD. We interpret results in relation to constrained variability of exposures and outcomes and discuss implications for valid research on social determinants of health.     

Susceptibility of brown adipocytes to pro-inflammatory cytokine toxicity and reactive oxygen species

Brown adipose tissue (BAT) cells have a very high oxidative capacity. On the other hand, in obesity and obesity-related diabetes, levels of pro-inflammatory cytokines are elevated, which might promote BAT dysfunction and consequently impair carbohydrate metabolism and thereby exacerbate cellular dysfunction and promote diabetes progression. Therefore, the antioxidative enzyme status of a brown adipocyte cell line and its susceptibility towards pro-inflammatory cytokines, which participate in the pathogenesis of diabetes, and reactive oxygen species (ROS) were analysed. Mature brown adipocytes exhibited significantly higher levels of expression of mitochondrially and peroxisomally located antioxidative enzymes compared with non-differentiated brown adipocytes. Pro-inflammatory cytokines induced a significant decrease in the viability of differentiated brown adipocytes, which was accompanied by a massive ROS production and down-regulation of BAT-specific markers, such as uncoupling protein 1 (UCP-1) and β-Klotho. Taken together, the results strongly indicate that pro-inflammatory cytokines cause brown adipocyte dysfunction and death through suppression of BAT-specific proteins, especially of UCP-1 and β-Klotho, and consequently increased oxidative stress.