Relationship between diabetes risk and admixture in postmenopausal African-American and Hispanic-American women

AIMS/HYPOTHESIS

Type 2 diabetes is more prevalent in African-Americans (AFAs) and Hispanic-Americans (HAs) than in European-Americans. We assessed whether continental admixture was correlated with diabetes risk in these high-risk groups.

METHODS

We estimated the proportion of sub-Saharan African (AFR), Amerindian (AMI) and European admixture using 92 ancestry-informative marker genotypes in 16,476 AFA and HA women from the Women's Health Initiative. Cox regression models were used to examine the association between admixture and diabetes risk, with and without accounting for socioeconomic status (SES) and adiposity measurements.

RESULTS

AFR admixture was significantly associated with diabetes risk in AFA women when adjusting for entry age, neighbourhood SES and BMI or waist/hip ratio (WHR) (all p < 0.0001). In HA women, AMI admixture had significant associations with diabetes risk that remained significant after adjustment for SES and BMI (all p < 0.0005). In both AFAs and HAs, SES showed significant negative associations while BMI or WHR had significant positive associations with diabetes risk, with and without adjustment for genetic admixture.

CONCLUSIONS/INTERPRETATION

In AFAs, admixture, SES and BMI/WHR each independently contribute to diabetes risk after accounting for each of the other factors; in HAs, admixture, SES and BMI each independently contribute to diabetes risk after accounting for each of the other factors, whereas admixture is not significantly associated with diabetes risk after accounting for SES and WHR. The findings emphasise the importance of considering both genetic and environmental causes in the aetiology of type 2 diabetes.

Biologia e tabela de vida de fertilidade de Spodoptera frugiperda (J.E. Smith) em linhagens de milho

O objetivo deste trabalho foi estudar os aspectos biológicos de Spodoptera frugiperda (J. E. Smith) e elaborar a tabela de vida de fertilidade deste inseto em cinco linhagens de milho provenientes do Programa de Melhoramento de Milho da Embrapa Clima Temperado. Foram determinadas a duração e sobrevivência das fases de ovo, larva, pré-pupa e pupa, peso de pupas, deformações, longevidade, fecundidade e período de pré-oviposição. A linhagem M89611 não permitiu aos insetos realizarem postura. A duração do período de lagarta, pré-pupa, pupa e adultos foram de 10,67, 1,22, 2,13 e 21,33 dias, respectivamente. O peso de pupa para esta linhagem foi de 0,129 e 0,091g para fêmeas e machos, respectivamente. As deformações foram de 25% e a longevidade de 21,3 dias. S. frugiperda aumentou 20,22 vezes a cada geração para a linhagem M89420, com duração média de 37,26 dias e a razão finita de aumento foi de 1,06668. A linhagem M89611 afeta a biologia de S. frugiperda, enquanto que, a linhagem M89287 proporciona maior viabilidade das fases de desenvolvimento e a linhagem M89420 proporciona a maior taxa líquida de reprodução.

Assessing the ability of mechanistic volatilization models to simulate soil surface conditions: a study with the Volt'Air model

Ammonia and pesticide volatilization in the field is a surface phenomenon involving physical and chemical processes that depend on the soil surface temperature and water content. The water transfer, heat transfer and energy budget sub models of volatilization models are adapted from the most commonly accepted formalisms and parameterizations. They are less detailed than the dedicated models describing water and heat transfers and surface status. The aim of this work was to assess the ability of one of the available mechanistic volatilization models, Volt'Air, to accurately describe the pedo-climatic conditions of a soil surface at the required time and space resolution. The assessment involves: (i) a sensitivity analysis, (ii) an evaluation of Volt'Air outputs in the light of outputs from a reference Soil-Vegetation-Atmosphere Transfer model (SiSPAT) and three experimental datasets, and (iii) the study of three tests based on modifications of SiSPAT to establish the potential impact of the simplifying assumptions used in Volt'Air. The analysis confirmed that a 5 mm surface layer was well suited, and that Volt'Air surface temperature correlated well with the experimental measurements as well as with SiSPAT outputs. In terms of liquid water transfers, Volt'Air was overall consistent with SiSPAT, with discrepancies only during major rainfall events and dry weather conditions. The tests enabled us to identify the main source of the discrepancies between Volt'Air and SiSPAT: the lack of gaseous water transfer description in Volt'Air. They also helped to explain why neither Volt'Air nor SiSPAT was able to represent lower values of surface water content: current classical water retention and hydraulic conductivity models are not yet adapted to cases of very dry conditions. Given the outcomes of this study, we discuss to what extent the volatilization models can be improved and the questions they pose for current research in water transfer modeling and parameterization.

Cell engineering for muscle gene therapy: Extemporaneous production of retroviral vector packaging macrophages using defective herpes simplex virus type 1 vectors harbouring gag, pol, env genes

Gene therapy as a treatment for neuromuscular diseases is an ever-developing concept based on the use of DNA as the therapeutic agent. In the search for appropriate strategies a bottleneck exists, however, concerning the targeting of vectors carrying the therapeutic gene, to all pathologic sites. These diseases are often characterised by multiple widespread lesions spread over a large area, rendering administration by local injection into tissues, clinically irrelevant. With this in mind, we have proposed that circulating cells (monocytes/macrophages), which home naturally to inflammatory lesions, characteristic of degenerating muscle, could be used as shuttles able to track down every damaged site, and deliver there a corrective gene. Our aim is to mobilise a corrective gene from these infiltrating monocyte-macrophages, into muscle cells, a process of in situ cell to cell gene transfer which could be accomplished using a retroviral vector, since the regeneration process involves the proliferation of muscle precursors before they fuse to form replacement fibres. For this, monocyte-macrophages must be engineered into 'packaging cells' containing both the replication deficient retrovirus carrying the gene of interest and an helper genome (gag-pol-env) needed for its assembly and secretion. Here, we have transduced a monocyte cell line using a defective murine Moloney leukemia retrovirus carrying the LacZ reporter gene. This provided us with a platform to investigate the possibility of gag-pol-env vector driven packaging of the defective retrovirus by macrophages. We show that an herpes simplex virus type I amplicon harbouring the Moloney gag, pol, env sequences is able to rescue the defective retrovirus vector from macrophages, allowing gene transfer into muscle precursor cells. After fusion, these cells gave rise to genetically modified myotubes in vitro.

Relationship between adiposity and admixture in African-American and Hispanic-American women

Objective

To investigate whether differences in admixture in African American (AFA) and Hispanic American (HA) adult women are associated with adiposity and adipose distribution.

Design

The proportion of European, sub– Saharan African and Amerindian admixture was estimated for AFA and HA women in the Women's Heath Initiative using 92 ancestry informative markers. Analyses assessed the relationship between admixture and adiposity indices.

Subjects

11712 AFA and 5088 HA self– identified post– menopausal women.

Results

There was a significant positive association between body mass index (BMI) and African admixture when BMI was considered as a continuous variable, and age, education, physical activity, parity, family income and smoking were included covariates (p < 10^{− 4}). A dichotomous model (upper and lower BMI quartiles) showed that African admixture was associated with a high odds ratio [OR = 3.27 (for 100% admixture compared to 0% admixture), 95% confidence interval (CI) 2.08 – 5.15]. For HA there was no association between BMI and admixture. In contrast, when waist to hip ratio (WHR) was used as a measure of adipose distribution, there was no significant association between WHR and admixture in AFA but there was a strong association in HA (p<10^{− 4}; OR Amerindian admixture = 5.93, CI = 3.52 – 9.97).

Conclusion

These studies show that 1) African admixture is associated with BMI in AFA women; 2) Amerindian admixture is associated with WHR but not BMI in HA women; and 3) it may be important to consider different measurements of adiposity and adipose distribution in different ethnic population groups.

Alpha-tocopherol concentration in the colostrum of nursing women supplemented with retinyl palmitate and alpha-tocopherol

BACKGROUND

Vitamins A and E are recognisably important in the initial stages of life, and the newborn depends on nutritional adequacy of breast milk to meet their needs. These vitamins share routes of transport to the tissues and antagonistic effects have been observed in animals after supplementation with vitamin A. The present study aimed to determine the effect of maternal supplementation with a megadose of retinyl palmitate in the immediate post-partum on α-tocopherol concentration in the colostrum.

METHODS

Healthy parturient women at a Brazilian public maternity were recruited for the study and divided into two groups: control (n = 37) and supplemented (n = 36). Blood and colostrum samples were collected up to 16 h post-partum. The supplemented group was administered with a retinyl palmitate capsule and, 24 h after the first collection, the second colostrum sample was obtained in the two groups for analysis of α-tocopherol. The cut-off points for deficiency are <1.05 μmol L(-1) for retinol and <11.6 μmol L(-1) for α-tocopherol.

RESULTS

The mean (SD) serum concentration of 1.77 (0.50) μmol L(-1) for retinol and 30.81 (6.46) μmol L(-1) for α-tocopherol indicates an adequate biochemical status. The supplemented group showed an increase of α-tocopherol in the colostrum 24 h after supplementation (P = 0.04), and this finding was not observed in the control group.

CONCLUSIONS

Supplementation with a 200,000 IU megadose of vitamin A did not negatively affect α-tocopherol levels in colostrum.