Iodine nutrition and breast feeding

A survey of the databanks Medline and Web of science identified studies dealing with maternal and infant iodine nutrition during breast feeding. The iodine concentration of human milk varies widely due to maternal iodine intake. Mean breast milk iodine concentrations are reported as ranging from 5.4 to 2170 μg/L (median 62 μg/L) in worldwide studies. In the few studies that compared length of lactation, gestation length, and parity number, these factors did not significantly affect milk-iodine concentrations. In studies of maternal iodine deficiency, untreated goiter had no impact on breast milk iodine when compared with controls. Iodine in human milk responds quickly to dietary iodine intake, either supplemented or consumed in natural foods. Easily absorbable iodine from foods, supplemental sources, iodine-based medication or iodine-based antiseptic solutions used during parturition, is taken up by the maternal thyroid and mammary glands through the Na⁺/I⁻ symporter system. This transmembrane carrier protein transports iodine against a high concentration gradient. Hormonal iodine in breast milk occurs mainly as T-4, but depending on maternal iodine intake, high concentrations of the inorganic form (iodide) are found. In less developed countries, where natural-food-iodine intake is low, adequate maternal iodine nutritional status depends exclusively on enforcement of food iodination. In industrialized countries, maternal iodine intake has increased as a function of increasing consumption of dairy products. The human infant is sensitive to maternal iodine nutrition during fetal development and later during breast feeding. Environmental factors, not directly related to maternal iodine intake, such as intake of selenium and organochlorine pollutants, can affect thyroid hormone homeostasis in breast-fed infants. In spite of low iodine concentrations found in milk of mothers consuming low-iodine natural foods, long lasting or even life-lasting benefits to the breast-fed infant are demonstrable.     

Repeated predatory attacks and multiple decisions to come out from a refuge in an alpine lizard

Prey often respond to predator presence by increasing theiruse of refuges. However, because the use of refuges may entailseveral costs, the decision of when to come out from a refugeshould be optimized. In some circumstances, if predators remainwaiting outside the refuge and try new attacks or if predator density increases, the prey may suffer successive repeated attacksin a short time. Successive attacks may represent an increasein the risk of predation, but the costs of refuge use alsomay increase with time spent in the refuge. Thus, prey shouldmake multiple related decisions on when to emerge from the refuge after each new attack. We simulated in the field repeatedpredatory attacks to the same individuals of the lizard Lacertamonticola and specifically examined the variation in successivetimes to emergence from a refuge under different thermal conditions(i.e., different costs of refuge use). The results showed thatrisk of predation but also thermal costs of refuge use affectedthe emergence decisions. Lizards increased progressively theduration of time spent in the refuge between successive emergencetimes when the costs of refuge use were lower, but tended tomaintain or to decrease the duration of time spent in the refugebetween successive emergence times when cost of refuge useincreased. Additionally, lizards that entered the refuge withhigher body temperatures had overall emergence times of longer duration. Optimization of refuge use and flexibility in theantipredator responses might help lizards to cope with increasedpredation risk without incurring excessive costs of refugeuse.     

Stabilization of a tetrameric enzyme (α-amino acid ester hydrolase from Acetobacter turbidans) enables a very improved performance of ampicillin synthesis

The stabilized derivative of the enzyme α-amino acid ester hydrolase from Acetobacter turbidans has been found to be very adequate as biocatalyst of the synthesis of the very relevant antibiotic ampicillin. This enzyme resulted much more adequate than the Penicillin G Acylase (PGA) from Escherichia coli (the most used enzyme). The stabilization of the enzyme was required because under optimal conditions (absence of phosphate and 40% of MeOH), no-stabilized derivatives or soluble enzyme from A. turbidans become very rapidly inactivated. Under these conditions, this new stabilized derivative exhibited a very high selectivity for the transferase activity compared to the esterase one, as well as a very low hydrolytic activity towards the antibiotic. Moreover, this new biocatalyst did not recognize -phenylglycine as substrate in the synthetic process. By using the racemic mixture of / phenylglycine methyl ester, 85% of the -ester could be transformed to ampicillin. In contrast, the enzyme from E. coli exhibited a high hydrolytic activity for the ampicillin yielding low synthetic yields. This enzyme also resulted much less enantioselective producing both isomers of the antibiotic.     

Emulsifiers from solid and liquid polyols: different strategies for obtaining optimum conversions and selectivities

The present paper provides a general overview of the factors involved in both the kinetics and the selectivity of partial acylation reactions of polyols (sugars). Different kinetic strategies for maximum production of intermediate esters of various polyols and monosaccharides are reported and discussed. Physicochemical requirements for obtaining maximum selectivities and complementary strategies for reducing reaction times are discussed. The reactions studied include glycerol, glucose, fructose, mannose, sorbitol and an alkyl glucoside as precursors. The high selectivity towards the monoglyceride in the presence and absence of a solvent has been attributed to a combination of the precipitation of the desired ester, use of glycerol in excess and the relatively low solubility of the fatty acid in the system. Unlike the reaction in the presence of a solvent, the reaction in a solvent-free medium produces the diester first. The monoester only accumulates in the medium as a consequence of disproportionation and glycerolysis reactions of the diester formed earlier. Selective esterification of solid sugars (polyols) which have an intermediate solubility in acetone is favored at low temperatures at which a sufficient amount of polyol dissolves and concurrent precipitation of the desired product can be achieved. By contrast, use of elevated temperatures is more appropriate for selective partial esterification of polyols, which are the most soluble in the solvent employed. Polyols (sugars) which are the less soluble into the liquid reaction phase cannot be easily esterified. Diffusional limitations on the rate of dissolution of the solid precursor can be minimized by increasing the surface area of the solid polyol.     

Raking Kappa: Describing Potential Impact of Marginal Distributions on Measures of Agreement

Several authors have noted the dependence of kappa measures of inter-rater agreement on the marginal distributions of contingency tables displaying the joint ratings. This paper introduces a smoothed version of kappa computed after raking the table to achieve pre-specified marginal distributions. A comparison of kappa with raked kappa for various margins can indicate the extent of the dependence on the margins, and can indicate how much of the lack of agreement is due to marginal heterogeneity.     

Dual miRNA Targeting Restricts Host Range and Attenuates Neurovirulence of Flaviviruses

Mosquito-borne flaviviruses are among the most significant arboviral pathogens worldwide. Vaccinations and mosquito population control programs remain the most reliable means for flavivirus disease prevention, and live attenuated viruses remain one of the most attractive flavivirus vaccine platforms. Some live attenuated viruses are capable of infecting principle mosquito vectors, as demonstrated in the laboratory, which in combination with their intrinsic genetic instability could potentially lead to a vaccine virus reversion back to wild-type in nature, followed by introduction and dissemination of potentially dangerous viral strains into new geographic locations. To mitigate this risk we developed a microRNA-targeting approach that selectively restricts replication of flavivirus in the mosquito host. Introduction of sequences complementary to a mosquito-specific mir-184 and mir-275 miRNAs individually or in combination into the 3’NCR and/or ORF region resulted in selective restriction of dengue type 4 virus (DEN4) replication in mosquito cell lines and adult Aedes mosquitos. Moreover a combined targeting of DEN4 genome with mosquito-specific and vertebrate CNS-specific mir-124 miRNA can silence viral replication in two evolutionally distant biological systems: mosquitoes and mouse brains. Thus, this approach can reinforce the safety of newly developed or existing vaccines for use in humans and could provide an additional level of biosafety for laboratories using viruses with altered pathogenic or transmissibility characteristics.     

Decision-making during NHEJ: a network of interactions in human Polμ implicated in substrate recognition and end-bridging

Human Polμ is a DNA polymerase belonging to the X family that has been implicated in the non-homologous end-joining (NHEJ) pathway during repair of double-strand breaks in DNA. Loop1 is a flexible piece of Polμ which has a critical role during terminal transferase and end-joining activities: it acts as a pseudo-template when the template strand is discontinuous or unavailable, whilst diffusing away if present to avoid steric clashes. Mutational analysis and inspection of the 3D structures available allowed us to identify a network of residues in charge of sensing the presence or absence of discontinuities in the template strand, which will in turn determine the final position adopted by Loop1. This network is formed by the previously uncharacterized thumb mini-loop (NSH motif) and the positively charged helix N, which contribute to the correct positioning of Loop1 and to juxtapose the discontinuous template strand during NHEJ of incompatible ends. Accordingly, single mutation of specific conserved residues in these motifs, whilst irrelevant in most of the cases for gap filling, largely affected terminal transferase and end-joining activities. Other point mutations in the ‘hinges’ of Loop1, such as residues Phe³⁸⁵ or Phe³⁸⁹, corroborated the flexibility requirements of this motif.     

New perspectives in radiation oncology: Young radiation oncologist point of view and challenges

AimTo assess the role of the young radiation oncologist in the context of important recent advancements in the field of radiation oncology, and to explore new perspectives and competencies of the young radiation oncologist.BackgroundRadiation oncology is a field that has rapidly advanced over the last century. It holds a rich tradition of clinical care and evidence-based practice, and more recently has advanced with revolutionary innovations in technology and computer science, as well as pharmacology and molecular biology.Materials and methodsSeveral young radiation oncologists from different countries evaluated the current status and future directions of radiation oncology.ResultsFor young radiation oncologists, it is important to reflect on the current practice and future directions of the specialty as it relates to the role of the radiation oncologist in the comprehensive management of cancer patients. Radiation oncologists are responsible for the radiation treatment provided to patients and its subsequent impact on patients’ quality of life. Young radiation oncologists must proactively master new clinical, biological and technical information, as well as lead radiation oncology teams consisting of physicists, dosimetrists, nurses and technicians.ConclusionsThe role of the young radiation oncologist in the field of oncology should be proactive in developing new competencies. Above all, it is important to remember that we are dealing with the family members and loved ones of many individuals during the most difficult part of their lives.     

Molecular masses of cAMP-binding proteins in yeasts

Abstract The cAMP-binding proteins of different yeasts were photoaffinity labeled using 8- N ₃-[³²P]cAMP, and the M _r values of the labeled proteins estimated by SDS-polyacrylamide gel electrophoresis. The M _r values of the cAMP-binding proteins may be grouped into two size classes: (A) M _r of about 50 000 represented by Saccharomyces cerevisiae and S. uvarum , and (B) M _r of about 60 000 represented by Kluyveromyces fragilis, K. lactis, K. marxianus, S. globosus and S. rouxii .