MEASUREMENTS OF SMALL AMOUNTS OF Hsub2sub 2O IN Dsub2sub 2O BY NEAR-INFRARED ABSORPTION SPECTROSCOPY

The literature on the near-infrared and infrared absorption spectra of liquid H/sub 2/O and D/sub 2/O as well as other literature related to the determination of small amounts of one in the presence of the other was reviewed. Nearinfrared absorption techniques appear to be very convenient, rapid, and almost ideally suited for the determination of H/sub 2/O in the concentration range from 0 to 10% in D/sub 2/O. The absorption spectra of H/sub 2/O, D/sub 2/ O, (HDO), and of mixtures of H/sub 2/O in D/sub 2/O were obtained using a Cary Model l4 PM Recording Spectrophotometer. As expected. the H/sub 2/O was found to undergo very rapid and almost complete exchange to HDO, especially at relatively low H/sub 2/O concentrations. In agreement with some previously reported French and Japanese work, a relatively intense and very useful absorption band for HDO has been found at l.668 mu , and it is used for the determination. By the use of the procedure described. 0.5, 2, 4, and 7 wt.% H/sub 2/O in D/sub 2/O can be determined with respective approximate relative standard deviations of 7, 2, 1, and 0.7% when 1-cm absorption cells are used in conjunction with a pure D/sub 2/O reference liquid. (auth

Brain glucose sensing, glucokinase and neural control of metabolism and islet function.

It is increasingly apparent that the brain plays a central role in metabolic homeostasis, including the maintenance of blood glucose. This is achieved by various efferent pathways from the brain to periphery, which help control hepatic glucose flux and perhaps insulin-stimulated insulin secretion. Also, critically important for the brain given its dependence on a constant supply of glucose as a fuel--emergency counter-regulatory responses are triggered by the brain if blood glucose starts to fall. To exert these control functions, the brain needs to detect rapidly and accurately changes in blood glucose. In this review, we summarize some of the mechanisms postulated to play a role in this and examine the potential role of the low-affinity hexokinase, glucokinase, in the brain as a key part of some of this sensing. We also discuss how these processes may become altered in diabetes and related metabolic diseases.Funding and support from Wellcome Trust, Medical Research Council including the Cambridge MRC Centre for Study of Obesity and Related Disorders (MRC-CORD), NIHR Cambridge Biomedical Research Centre, Diabetes UK (RD05/003059) and Yousef Jameel Fund).This is the final version published version. It first appeared at http://onlinelibrary.wiley.com/doi/10.1111/dom.12334/abstract

Metabolomics and its application for non-invasive embryo assessment in IVF

Morphology and cleavage rate remain the mainstay of embryo assessment. However, a number of additional technologies for this application are under investigation. These include the measurement of glucose, lactate, pyruvate or amino acid levels in the embryo culture media, assessment of oxygen consumption by the embryo, genomic and proteomic profiling, and most recently, analytical examination of the embryonic metabolome. As the number of assisted reproduction cycles increases worldwide, improvements in the ability to quickly and non-invasively identify the best embryos for transfer remain a critical goal for reproductive medicine. Recent studies suggest that metabolomic profiling of embryo culture media using optical and non-optical spectroscopies may provide a useful adjunct to the current embryo assessment strategies and provide insight into the phenotype of embryos with increasing reproductive potential

Hypercholesterolemia Impaired Sperm Functionality in Rabbits

Hypercholesterolemia represents a high risk factor for frequent diseases and it has also been associated with poor semen quality that may lead to male infertility. The aim of this study was to analyze semen and sperm function in diet-induced hypercholesterolemic rabbits. Twelve adult White New Zealand male rabbits were fed ad libitum a control diet or a diet supplemented with 0.05% cholesterol. Rabbits under cholesterol-enriched diet significantly increased total cholesterol level in the serum. Semen examination revealed a significant reduction in semen volume and sperm motility in hypercholesterolemic rabbits (HCR). Sperm cell morphology was seriously affected, displaying primarily a “folded head”-head fold along the major axe-, and the presence of cytoplasmic droplet on sperm flagellum. Cholesterol was particularly increased in acrosomal region when detected by filipin probe. The rise in cholesterol concentration in sperm cells was determined quantitatively by Gas chromatographic-mass spectrometric analyses. We also found a reduction of protein tyrosine phosphorylation in sperm incubated under capacitating conditions from HCR. Interestingly, the addition of Protein Kinase A pathway activators -dibutyryl-cyclic AMP and iso-butylmethylxanthine- to the medium restored sperm capacitation. Finally, it was also reported a significant decrease in the percentage of reacted sperm in the presence of progesterone. In conclusion, our data showed that diet-induced hypercholesterolemia adversely affects semen quality and sperm motility, capacitation and acrosomal reaction in rabbits; probably due to an increase in cellular cholesterol content that alters membrane related events

Reduced levels of two modifiers of epigenetic gene silencing, Dnmt3a and Trim28, cause increased phenotypic noise

Background: Inbred individuals reared in controlled environments display considerable variance in many complex traits but the underlying cause of this intangible variation has been an enigma. Here we show that two modifiers of epigenetic gene silencing play a critical role in the process.Results: Inbred mice heterozygous for a null mutation in DNA methyltransferase 3a (Dnmt3a) or tripartite motif protein 28 (Trim28) show greater coefficients of variance in body weight than their wild-type littermates. Trim28 mutants additionally develop metabolic syndrome and abnormal behavior with incomplete penetrance. Genome-wide gene expression analyses identified 284 significantly dysregulated genes in Trim28 heterozygote mutants compared to wild-type mice, with Mas1, which encodes a G-protein coupled receptor implicated in lipid metabolism, showing the greatest average change in expression (7.8-fold higher in mutants). This gene also showed highly variable expression between mutant individuals.Conclusions: These studies provide a molecular explanation of developmental noise in whole organisms and suggest that faithful epigenetic control of transcription is central to suppressing deleterious levels of phenotypic variation. These findings have broad implications for understanding the mechanisms underlying sporadic and complex disease in humans

Dietary Deficiency of Essential Amino Acids Rapidly Induces Cessation of the Rat Estrous Cycle

Reproductive functions are regulated by the sophisticated coordination between the neuronal and endocrine systems and are sustained by a proper nutritional environment. Female reproductive function is vulnerable to effects from dietary restrictions, suggesting a transient adaptation that prioritizes individual survival over reproduction until a possible future opportunity for satiation. This adaptation could also partially explain the existence of amenorrhea in women with anorexia nervosa. Because amino acid nutritional conditions other than caloric restriction uniquely alters amino acid metabolism and affect the hormonal levels of organisms, we hypothesized that the supply of essential amino acids in the diet plays a pivotal role in the maintenance of the female reproductive system. To test this hypothesis, we examined ovulatory cyclicity in female rats under diets that were deficient in threonine, lysine, tryptophan, methionine or valine. Ovulatory cyclicity was monitored by daily cytological evaluations of vaginal smears. After continuous feeding of the deficient diet, a persistent diestrus or anovulatory state was induced most quickly by the valine-deficient diet and most slowly by the lysine-deficient diet. A decline in the systemic insulin-like growth factor 1 level was associated with a dietary amino acid deficiency. Furthermore, a paired group of rats that were fed an isocaloric diet with balanced amino acids maintained normal estrous cyclicity. These disturbances of the estrous cycle by amino acid deficiency were quickly reversed by the consumption of a normal diet. The continuous anovulatory state in this study is not attributable to a decrease in caloric intake but to an imbalance in the dietary amino acid composition. With a shortage of well-balanced amino acid sources, reproduction becomes risky for both the mother and the fetus. It could be viewed as an adaptation to the diet, diverting resources away from reproduction and reallocating them to survival until well-balanced amino acid sources are found

Screaming 'Black' Murder: Crime Fiction and the Construction of Ethnic Identities

A significant segment of crime fiction is concerned with the representation of ethnic identities and may to some extent be considered paradigmatic of the participation of literary texts in discourses on race and minorities. This article explores constructions of ethnic identities in American, British, and South African crime fiction from the 1920s to the early twenty-first century. In particular, the focus will be on such texts in which the ethno-cultural identity of the detective gives special prominence not only to the ethnic particularity of the fictional character itself and of its environs but frequently also to that of its author. Main texts discussed are Rudolph Fisher’s The Conjure Man Dies (1932), Earl Derr Biggers’ The House Without a Key (1925) and The Black Camel (1929), Walter Mosley’s Devil in a Blue Dress (1990) and Little Scarlet (2004) as well as James McClure’s The Gooseberry Fool (1974) and Patrick Neate’s City of Tiny Lights (2005). It is argued that all of these texts have a distinct subversive potential of which the construction of ethnic identities becomes the main vehicle because these identities are the products and the catalysts of the conflicts negotiated in ethnic crime fiction and correlating to ‘reality’

Ouabain Stimulates a Na+/K+-ATPase-Mediated SFK-Activated Signalling Pathway That Regulates Tight Junction Function in the Mouse Blastocyst

The Na+/K+-ATPase plays a pivotal role during preimplantation development; it establishes a trans-epithelial ionic gradient that facilitates the formation of the fluid-filled blastocyst cavity, crucial for implantation and successful pregnancy. The Na+/K+-ATPase is also implicated in regulating tight junctions and cardiotonic steroid (CTS)-induced signal transduction via SRC. We investigated the expression of SRC family kinase (SFK) members, Src and Yes, during preimplantation development and determined whether SFK activity is required for blastocyst formation. Embryos were collected following super-ovulation of CD1 or MF1 female mice. RT-PCR was used to detect SFK mRNAs encoding Src and Yes throughout preimplantation development. SRC and YES protein were localized throughout preimplantation development. Treatment of mouse morulae with the SFK inhibitors PP2 and SU6656 for 18 hours resulted in a reversible blockade of progression to the blastocyst stage. Blastocysts treated with 10−3 M ouabain for 2 or 10 minutes and immediately immunostained for phosphorylation at SRC tyr418 displayed reduced phosphorylation while in contrast blastocysts treated with 10−4 M displayed increased tyr418 fluorescence. SFK inhibition increased and SFK activation reduced trophectoderm tight junction permeability in blastocysts. The results demonstrate that SFKs are expressed during preimplantation development and that SFK activity is required for blastocyst formation and is an important mediator of trophectoderm tight junction permeability

American marsupials chromosomes: Why study them?

Marsupials, one of the three main groups of mammals, are only found in Australia and in the American continent. Studies performed in Australian marsupials have demonstrated the great potential provided by the group for the understanding of basic genetic mechanisms and chromosome evolution in mammals. Genetic studies in American marsupials are relatively scarce and cytogenetic data of most species are restricted to karyotype descriptions, usually without banding patterns. Nevertheless, the first marsupial genome sequenced was that of Monodelphis domestica, a South American species. The knowledge about mammalian genome evolution and function that resulted from studies on M. domestica is in sharp contrast with the lack of genetic data on most American marsupial species. Here, we present an overview of the chromosome studies performed in marsupials with emphasis on the South American species