551 research outputs found
Endocrine-disrupting chemicals and their effects during female puberty: A review of current evidence
Puberty is the process of physical changes between childhood and adulthood during which adolescents reach sexual maturity and become capable of reproduction. It is considered one of the main temporal windows of susceptibility for the influence of the endocrine-disrupting chemicals (EDCs). EDCs may act as single chemical agents or as chemical mixtures; they can be pubertal influencers, accelerating and anticipating the processing of maturation of secondary sexual characteristics. Moreover, recent studies have started to point out how exposure to EDCs during puberty may predispose to breast cancer later in life. In fact, the estrogen-mimicking endocrine disruptors (EEDs) may influence breast tissue development during puberty in two main ways: the first is the action on the proliferation of the breast stromal cells, the second concerns epigenetic mechanisms. The aim of this mini-review was to better highlight what is new and what is not completely known regarding the role of EDCs during puberty
Early Skin-to-Skin Contact in Preterm Infants: Is It Safe? An Italian Experience
Background: Skin-to-skin contact (SSC) is one of the four components of kangaroo care (KC) and is also a valued alternative to incubators in low-income countries. SSC has also become a standard of care in high-income countries because of its short- and long-term benefits and its positive effect on infant growth and neurodevelopmental outcome. However, barriers in the implementation of SSC, especially with preterm infants, are common in NICUs because parents and health care professionals can perceive it as potentially risky for the clinical stability of preterm infants. Previous studies have assessed safety before and during SSC by monitoring vital parameters during short-time intervals. Aims: To demonstrate the safety of early SSC in preterm infants during at least 90 min intervals. Design: Prospective observational monocentric study. Methods: Preterm infants born between June 2018 and June 2020 with a gestational age of ≤33 weeks and a birth weight of <2000 g were monitored while performing an SSC session during the first three weeks of life. Infants with necrotizing enterocolitis, sepsis, and congenital malformations on mechanical ventilation or with more than five apneas in the hour before SSC were excluded. Continuous oxygen saturation (SaO2), heart rate (HR), and respiratory rate (RR) were registered during an SSC session and in the hour before. The minimum duration of an SSC session was 90 min. Information regarding postmenstrual age (PMA), body weight, respiratory support, presence of a central venous catheter and the onset of sepsis within 72 h after a session was collected. Two physicians, blinded to infant conditions and the period of analysis (before or during SSC), evaluated desaturation episodes (SaO2 < 85%, >15 s), bradycardia (HR < 100, >15 s) and apneas (pause in breathing > 20 s associated with desaturation and/or bradycardia). A Wilcoxon rank sum test was used for the statistical analysis. Results: In total, 83 episodes of SSC were analyzed for a total of 38 infants. The mean gestational age at birth was 29 weeks (range 23–33 weeks). Median PMA, days of life, and body weight at SSC were 31 weeks (range 25–34 weeks), 10 days (range 1–20 days), and 1131 g (range 631–2206 g), respectively. We found that 77% of infants were on respiratory support and 47% of them had a central venous catheter (umbilical or peripherally inserted central catheter) during SSC. The total duration of desaturation, bradycardia, and the number of apneas were not statistically different during the SSC session and the hour before. No catheter dislocation or ruptures were reported. Conclusions: These findings highlighted the safety of early SSC in preterm infants and the possibility of performing it in an intensive care setting in the first weeks of life. In addition, these findings should reassure health care professionals offering this practice as a standard of care. SSC plays a key role in the care of preterm infants due to its short- and long-term positive benefits, and it deserves to be increasingly offered to infants and their parents
Diazotrophy drives primary production in the organic-rich shales deposited under a stratified environment during the messinian salinity crisis (Vena Del Gesso, Italy)
Density stratification between freshwater and brine is periodically formed during massive evaporation events, which often associates deposition of organic-rich sediments. Here, we investigated phototrophic communities and nitrogen cycle during the deposition of two organic-rich shale beds of gypsum\u2013shale alternation, representing the initial stage of the Messinian salinity crisis (Vena del Gesso, Northern Apennines, Italy). The structural distributions and the carbon and nitrogen isotopic compositions of geoporphyrins show a common pattern in the two shales, indicating the predominance of a particular phototrophic community under freshwater\u2013brine stratified conditions. The 3c6\u2030 difference in \u3b413C of total organic carbon between PLG 4 and 5 shales was associated with similar shift in \u3b413C of the porphyrins derived from chlorophyll c, suggesting that the eukaryotic algae producing chlorophyll c were the major constituent of the phototrophic community. Importantly, these porphyrins show \u3b415N values (-7.6\u2013-4.7\u2030) indicative of N2-fixation. We suggest that nitrate-depletion in the photic zone induced the predominance of diazotrophic cyanobacteria, which supplied new nitrogen for the chlorophyll c-producing eukaryotic algae. The large difference in the \u3b413C values of porphyrins and total organic carbon between PLG 4 and 5 shales are interpreted to reflect the depth of the chemocline, which fluctuates in response to changes in the regional evaporation\u2013precipitation balance. Such variation in the chemocline depth may have dynamically changed the mode of the nitrogen cycle (i.e., nitrification\u2013denitrification\u2013N2-fixation coupling vs. phototrophic assimilation of ammonium) in the density-stratified marginal basins during the Messinian salinity crisis
Microscopic theory of quantum-transport phenomena in mesoscopic systems: A Monte Carlo approach
A theoretical investigation of quantum-transport phenomena in mesoscopic
systems is presented. In particular, a generalization to ``open systems'' of
the well-known semiconductor Bloch equations is proposed. The presence of
spatial boundary conditions manifest itself through self-energy corrections and
additional source terms in the kinetic equations, whose form is suitable for a
solution via a generalized Monte Carlo simulation. The proposed approach is
applied to the study of quantum-transport phenomena in double-barrier
structures as well as in superlattices, showing a strong interplay between
phase coherence and relaxation.Comment: to appear in Phys. Rev. Let
Biomarker records and mineral compositions of the Messinian halite and K–Mg salts from Sicily
The evaporites of the Realmonte salt mine (Sicily, Italy) are important archives recording the most extreme conditions of
the Messinian Salinity Crisis (MSC). However, geochemical approach on these evaporitic sequences is scarce and little is
known on the response of the biological community to drastically elevating salinity. In the present work, we investigated
the depositional environments and the biological community of the shale–anhydrite–halite triplets and the K–Mg salt
layer deposited during the peak of the MSC. Both hopanes and steranes are detected in the shale–anhydrite–halite
triplets, suggesting the presence of eukaryotes and bacteria throughout their deposition. The K–Mg salt layer is
composed of primary halites, diagenetic leonite, and primary and/or secondary kainite, which are interpreted to have
precipitated from density-stratified water column with the halite-precipitating brine at the surface and the brineprecipitating
K–Mg salts at the bottom. The presence of hopanes and a trace amount of steranes implicates that
eukaryotes and bacteria were able to survive in the surface halite-precipitating brine even during the most extreme
condition of the MSC.This work was performed with the support of Japan Society for the
Promotion of Science (JSPS) Research Fellowship (16 J07844) to YI and
JAMSTEC President Fund to NO
Bifidobacterial biofilm formation is a multifactorial adaptive phenomenon in response to bile exposure
In the current study, we show that biofilm formation by various strains and species belonging to Bifidobacterium, a genus that includes gut commensals with reported health-promoting activities, is induced by high concentrations of bile (0.5% (w/v) or higher) and individual bile salts (20 mM or higher), rather than by acid or osmotic stress. The transcriptomic response of a bifidobacterial prototype Bifidobacterium breve UCC2003 to such high bile concentrations was investigated and a random transposon bank of B. breve UCC2003 was screened for mutants that affect biofilm formation in order to identify genes involved in this adaptive process. Eleven mutants affected in their ability to form a biofilm were identified, while biofilm formation capacity of an insertional mutation in luxS and an exopolysaccharide (EPS) negative B. breve UCC2003 was also studied. Reduced capacity to form biofilm also caused reduced viability when exposed to porcine bile. We propose that bifidobacterial biofilm formation is an adaptive response to high concentrations of bile in order to avoid bactericidal effects of high bile concentrations in the gastrointestinal environment. Biofilm formation appears to be a multi-factorial process involving EPS production, proteins and extracellular DNA release, representing a crucial strategy in response to bile stress in order to enhance fitness in the gut environment
Fetal hepatic calcification in severe KAT6A (Arboleda-Tham) syndrome
: Arboleda-Tham syndrome (ARTHS, MIM 616268) is a rare genetic disease, due to a pathogenic variant of Lysine (K) Acetyltransferase 6A (KAT6A) with autosomal dominant inheritance. Firstly described in 2015, ARTHS is one of the more common causes of undiagnosed syndromic intellectual disability. Due to extreme phenotypic variability, ARTHS clinical diagnosis is challenging, mostly at early stage of the disease. Moreover, because of the wide and unspecific spectrum of ARTHS, identification of the syndrome during prenatal life rarely occurs. Therefore, reported cases of KAT6A syndrome have been identified primarily through clinical or research exome sequencing in a gene-centric approach. In order to expands the genotypic and phenotypic spectrum of ARTHS, we describe prenatal and postnatal findings in a patient with a novel frameshift KAT6A pathogenic variant, displaying a severe phenotype with previously unreported clinical features
Bifidobacterium canis sp. Nov., a novel member of the bifidobacterium pseudolongum phylogenetic group isolated from faeces of a dog (canis lupus f. familiaris)
A fructose-6-phosphate phosphoketolase-positive strain (GSD1FST) was isolated from a faecal sample of a 3 weeks old German Shepherd dog. The closest related taxa to isolate GSD1FST based on results from the EZBioCloud database were Bifidobacte-rium animalis subsp. animalis ATCC 25527T, Bifidobacterium animalis subsp. lactis DSM 10140T and Bifidobacterium anseris LMG 30189T, belonging to the Bifidobacterium pseudolongum phylogenetic group. The resulting 16S rRNA gene identities (compared length of 1454 nucleotides) towards these taxa were 97.30, 97.23 and 97.09 %, respectively. The pairwise similarities of strain GSD1FST using argS, atpA, fusA, hsp60, pyrG, rpsC, thrS and xfp gene fragments to all valid representatives of the B. pseudo-longum phylogenetic group were in the concatenated range of 83.08–88.34 %. Phylogenomic analysis based on whole-genome methods such as average nucleotide identity revealed that bifidobacterial strain GSD1FST exhibits close phylogenetic relatedness (88.17 %) to Bifidobacetrium cuniculi LMG 10738T. Genotypic characteristics and phylogenetic analyses based on nine molecular markers, as well as genomic and comparative phenotypic analyses, clearly proved that the evaluated strain should be considered as representing a novel species within the B. pseudolongum phylogenetic group named as Bifidobacterium canis sp. nov. (GSD1FST=DSM 105923T=LMG 30345T=CCM 8806T)
Foot-to-Foot Contact Among Initial Goal-Directed Movements Supports the Prognostic Value of Fidgety Movements in HIE-Cooled Infants
Background: Few studies conducted to date have observed general movements in infants affected by hypoxic–ischemic encephalopathy (HIE) who underwent therapeutic hypothermia. We investigated whether foot-to-foot contact (FF) could support the predictive value of fidgety movements (FMs) in infants affected by HIE and treated with brain cooling. Methods: Spontaneous motility was video recorded for 3–5 min at 12 weeks post-term age in 58 full-term newborn infants affected by perinatal asphyxia who were cooled due to moderate to severe HIE. FF and FMs were blindly scored by three independent observers. At 24 months, each patient underwent a neurological examination by Amiel-Tison and Grenier. Results: At 24 months, 47 infants had developed typically at neurological examination, eight had developed mild motor impairment, and three developed cerebral palsy (CP). At 12 weeks, 34 (58.6%) infants had shown normal FMs, four of whom developed mild motor impairment. Twenty-four infants (41.4%) exhibited abnormal or no FMs, four of whom developed mild motor impairment and three developed CP. FF was present in 20 infants (34.5%), two of whom developed mild motor impairment. FF was absent in 38 infants (65.5%), six of whom developed mild motor impairment and three developed CP. Both FMs and FF, considered separately, were 100% sensitive for predicting CP at 24 months, but only 61 and 36%, respectively, were specific. Summing the two patterns together, the specificity increases to 73%, considering only CP as an abnormal outcome, and increases to 74% when considering CP plus mild motor impairment. Unexpectedly, fidgety movements were absent in 24 infants with typical motor outcomes, 17 of whom showed a typical motor outcome. Conclusions: FF is already part of motor repertoire at 12 weeks and allows a comparison of spontaneous non-voluntary movements (FMs) to pre-voluntary movements (FF). FF supports FMs for both sensitivity and specificity. A second video recording at 16–18 weeks, when pedipulation is present in healthy infants, is suggested: it may better define the presence or absence of goal-directed motility
Efficient recycling of nutrients in modern and past hypersaline environments
The biogeochemistry of hypersaline environments is strongly influenced by changes in biological
processes and physicochemical parameters. Although massive evaporation events have occurred
repeatedly throughout Earth history, their biogeochemical cycles and global impact remain poorly
understood. Here, we provide the first nitrogen isotopic data for nutrients and chloropigments from
modern shallow hypersaline environments (solar salterns, Trapani, Italy) and apply the obtained
insights to δ15N signatures of the Messinian salinity crisis (MSC) in the late Miocene. Concentrations
and δ15N of chlorophyll a, bacteriochlorophyll a, nitrate, and ammonium in benthic microbial mats
indicate that inhibition of nitrification suppresses denitrification and anammox, resulting in efficient
ammonium recycling within the mats and high primary productivity. We also suggest that the release
of 15N-depleted NH3(gas) with increasing salinity enriches ammonium 15N in surface brine (≈34.0‰).
Such elevated δ15N is also recorded in geoporphyrins isolated from sediments of the MSC peak (≈20‰),
reflecting ammonium supply sufficient for sustaining phototrophic primary production. We propose
that efficient nutrient supply combined with frequent bottom-water anoxia and capping of organic-rich
sediments by evaporites of the Mediterranean MSC could have contributed to atmospheric CO2
reduction during the late Miocene.This study was partly supported by a Japan Society for the Promotion of
Science (JSPS) Research Fellowship (16J07844) to YI, Grants-in-Aid (16H02236) and the JAMSTEC President
Fund to NO
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