Establishment of sex difference in circulating uric acid is associated with higher testosterone and lower sex hormone-binding globulin in adolescent boys

Men have higher circulating levels of uric acid than women. This sex difference is suspected to be a result of suppressive effects of estradiol on uric acid. If so, estradiol would be inversely associated with circulating uric acid. This study aimed to test this hypothesis. This cross-sectional study included 9472 participants (weighted sample size of 184,342,210) aged 12–80 years from the 2013 to 2016 US National Health and Nutrition Examination Survey. Associations of sex hormones with uric acid were analyzed using weighted least squares regression, adjusting for demographic characteristics, lifestyle risk factors, and comorbidities. Neither free nor bioavailable estradiol was inversely associated with circulating uric acid in adolescent boys or girls, or adult men or women, or perimenopausal women after full adjustment. The sex difference in uric acid was established during adolescence as a result of a dramatic increase in uric acid in adolescent boys. During adolescence, the increase in estradiol in girls over time was accompanied by a relatively unchanged level of uric acid. All three fractions of estradiol (free, bioavailable, and total) were positively associated with uric acid in adolescent boys and girls after full adjustment. In adolescent boys, all three fractions of testosterone were positively associated with serum uric acid, and sex hormone-binding globulin was inversely associated with uric acid after full adjustment. These results suggest that estradiol is not inversely associated with circulating uric acid in adolescents and the establishment of sex difference in circulating uric acid during adolescence is associated with higher testosterone and lower sex hormone-binding globulin in adolescent boys. © 2021, The Author(s)

MICROBIAL CHARACTERIZATION OF ABANDONED MINING AREA OF SIDI KAMBER NORTH-EAST OF ALGERI

The ecological importance of soil bacteria is not limited to their number or biomass, although these parameters contribute greatly. Indeed, their main asset lies in their great genetic and functional diversity. In this study carried out in the abandoned mine, located in Sidi Kamber (Oum Toub, Skikda, North-Est of Algeria) our objectives was to determine: a) contamination levels of this area by heavy metals b) heavy metal impact on bacterial communities and diversity c) possible risk on the ecological integrity of this area

PHYSIOLOGICAL AND BIOCHEMICAL MARKERS IN THE PROCESS OF RESISTANCE OF HEAVY METALS IN THE ABANDONED MINING AREA OF SIDI KAMBER, SKIKDA, ALGERIA

Mining activities produce large quantities of wastes which are highly contaminated with heavy metals. This can cause adverse effects on natural ecosystems, particularly on living organisms. The study reported here concerned the biomonitoring of pollution in the Sidi Kamber mining area, through the determination of various physiological mechanisms (bioaccumulation and translocation) and biochemical markers (chlorophyll (a) and (b), proline, total sugars and total proteins) active in resistance to heavy metals (Cd, Cu, Pb and Zn) contamination, using three plant species Cistus monspeliensis, Rumex bucephalophorus and Verbascum sinuatum as bioindicators

Metodologia para seleção de hortaliças com resistência à nematóides: alface/Meloidogyne spp.

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DNA copy number variations – Do these big mutations have a big effect on cardiovascular risk?

In simple terms, copy number variations or CNVs are replications or deletions in the DNA which, in humans, changes it from the normal number of two gene copies. These CNVs are caused by inherited or de novo structural changes such as duplications, insertions or deletions of repeated portions of genetic material (Fig. 1). These duplications can vary from one to ten or more copies and range in size from 50 DNA base pairs to several million [1]. Since their discovery in 1987 by Nakamura et al. [2], when they were initially named variable number tandem repeats, many studies have investigated their association with rare and common human diseases. Throughout evolution, some of these changes in copy number were beneficial such as the globin gene number duplication, while others such as the CNVs that cause Huntington's disease were not. In 2004, two landmark studies by Iafrate et al. [3] and Sebat et al. [4] found that large-scale copy-number variations, ranging in size from 100 kb to 2 Mb are common throughout the human genome, and that a high proportion of them are in known genes. These findings roused several association studies between CNVs and diseas

Reduced DNA methylation the human kidney is associated with increased blood pressure

Background and aims: There is increasing evidence that epigenetic modifications such as DNA methylation (addition of a methyl group to DNA (5mC) that leads to altered gene expression) is important to the development of common complex cardiovascular diseases. A recent study found that DNA methylation of blood cells is associated with blood pressure (BP). So far there has been no studies of epigenetic changes in the kidney, which is a key organ in BP regulation and the development of hypertension. The aim of this study was to examine associations between BP and the global methylation profiles of the kidney and blood. Methods and results: We used 93 human renal tissue samples from the TRANScriptome of RenaL HumAN TissueE (TRANSLATE) Study. All samples were collected from healthy, unaffected by cancer pole of the kidney after elective unilateral nephrectomies. DNA was extracted using the DNeasy Qiagen kit according to the protocol from blood and kidney samples. Global methylation was measured by ELISA assay to determine the percentage of 5mC in all DNA samples. A significant negative relationship was found between renal 5mC percentages and systolic (SBP) and diastolic (DBP) blood pressure (SBP r = -0.25, P = 0.018, DBP r = -0.32, P = 0.002). This correlation was also evident when BP is corrected for effects of antihypertensive medications (adjusted SBP P = 0.046, adjusted DBP P = 0.009). Comparatively, there was no significant relationship between 5mC percentage and BP in DNA extracted from peripheral blood leukocytes. Conclusions: We found a significant negative correlation between the percentage of 5mC and BP in the renal DNA samples indicating that reduced DNA methylation leads to increased blood pressure. No such relationship was established in the leukocyte DNA, indicating that blood may not be a good template for analysis of epigenetic modifications in the hypertensive population

Specificity of DNA methylation in the hypertensive kidney

Background: Evidence suggests that DNA methylation (5mC) is important in the development of essential hypertension (EH). The 5mC percentage, a measurement for global methylation studies, in peripheral blood leukocytes (PBL) has been previously associated with hypertension. Methylation patterns are tissue-specific, contributing to differences in transcriptional regulation and cellular differentiation. So far, there have been no studies of 5mC in the kidney – an important effector organ in EH. Furthermore, there has been no investigation of the relationship between 5mC patterns in the hypertensive kidney and PBLs. Aims: (i) To determine if global 5mC in the kidney is correlated to hypertension diagnosis and blood pressure (BP) regulation. (ii) To determine whether PBLs provide a surrogate for cross-tissue patterns of 5mC in the kidney. Methods: We used 96 human kidney and 76 human PBL samples from the TRANSLATE study to investigate global 5mC percentage. TRANSLATE consists of carefully characterized collections of "apparently healthy" specimens of human kidneys. Global methylation was determined using the 5mC ELISA kit (Zymo Research) that measures the total amount of 5mC present in a sample. Results: We found no association of global 5mC percentage in kidney (P=0.18) and PBL (P=0.54) with hypertension diagnosis, nor between PBL 5mC percentage and BP. However, a negative correlation was found between kidney 5mC percentage and systolic BP (r= –0.246; P <0.05), and diastolic BP (r= –0.319; P <0.01). This association was still evident after adjustment for antihypertensive medication for systolic BP (r= –0.210; P <0.05) and diastolic BP (r= –0.273; P <0.01). Furthermore, we found a strong positive correlation between normotensive kidneys and leukocyte 5mC percentages (r=0.864; P<0.01). Similarly, a strong positive correlation was evident for hypertensive kidneys and leukocyte 5mC percentages (r=0.916; P <0.01). Conclusion: Our findings show that kidney 5mC, but not PBL 5m C, is correlated to BP regulation. No relationship was evident for global 5mC and hypertension diagnosis, regardless of the tissue type studied. Furthermore, PBL 5mC global methylation percentage was highly correlated to kidney 5mC percentage. These results highlight the importance of further studies on the involvement of kidney DNA methylation in hypertension, as well as further investigation of the relationship between methylation patterns in the kidney and blood

Epidemics of Meloidogyne brasilensis on processing tomato hybrids carrying the Mi (Root-knot nematode resistance) gene in Central Brazil.

Resumo 176. Trabalho apresentado no 27º Congresso Paulista de Fitopatologia, 2003, Botucatu

Avaliação de acessos do banco de germoplasma de mandioquinha-salsa da Embrapa Hortaliças para resistência a Meloidogyne spp. no campo.

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