Adverse effects of 5-aza-2'-deoxycytidine on spermatogenesis include reduced sperm function and selective inhibition of de novo DNA methylation.

The anticancer agent, 5-aza-2'-deoxycytidine (5-azaCdR, decitabine), causes DNA hypomethylation and a robust, dose-dependent disruption of spermatogenesis. Previously, we have shown that altered testicular histology and reduced sperm production in 5-azaCdR-treated animals is associated with decreased global sperm DNA methylation and an increase in infertility and/or a decreased ability to support preimplantation embryonic development. The goal of this study was to determine potential contributors to 5-azaCdR-mediated infertility including alterations in sperm motility, fertilization ability, early embryo development, and sequence-specific DNA methylation.

Quantitation of phenylalanine and its trans-cinnamic, benzoic and hippuric acid metabolites in biological fluids in a single GC-MS analysis.

We describe a sensitive, simple and convenient stable isotope dilution assay developed to study endogenous metabolism of administered stable isotope-labeled phenylalanine (Phe) in phenylketonuric (PKU) mice treated experimentally with phenylalanine ammonia lyase (PAL). Mouse urine and plasma containing endogenous and administered labeled Phe together with internal standard Phe bearing a different pattern of labeling are converted by in situ diazotization to 2-chloro-3-phenylpropionic acid (CPP). A single solvent extraction is then used to isolate the isotopomers of CPP along with the trans-cinnamic acid (TCA) produced from Phe by PAL, as well as the TCA metabolites benzoic and hippuric acids.

Canonical WNT signaling during kidney development.

The canonical WNT signaling pathway plays a crucial role in patterning of the embryo during development, but little is known about the specific developmental events which are under WNT control. To understand more about how the WNT pathway orchestrates mammalian organogenesis, we studied the canonical beta-catenin-mediated WNT signaling pathway in kidneys of mice bearing a beta-catenin-responsive TCF/betaGal reporter transgene. In metanephric kidney, intense canonical WNT signaling was evident in epithelia of the branching ureteric bud and in nephrogenic mesenchyme during its transition into renal tubules.

Glucose enhances newborn memory for spoken words.

The effect of a 2 g/kg glucose feed was compared with a water feed on retention of a spoken word in 2-4 days old infants in a between group randomized trial. Infants heard a word in 30-s trials until they demonstrated orientation (head turns towards the sound) and habituation. After a 100 s delay, infants who received glucose turned toward the word less often than infants receiving water (means 31.

Genetic and nutritional deficiencies in folate metabolism influence tumorigenicity in Apcmin/+ mice.

Epidemiological studies indicate that adequate dietary folate is protective against colon cancer, although mechanisms remain largely elusive. We investigated the effects of genetic disruptions of folate transport and metabolism and of dietary folate deficiency in a mouse model of colon cancer, the Apc(min/+) mouse. Apc(min/+) mice with heterozygous knockout of the gene for reduced folate carrier 1 (Rfc1(+/-)) developed significantly fewer adenomas compared to Rfc1(+/+)Apc(min/+) mice [30.

Acquired and inherited disorders of cobalamin and folate in children.

Cobalamin deficiency in the newborn usually results from cobalamin deficiency in the mother. Megaloblastic anaemia, pancytopenia and failure to thrive can be present, accompanied by neurological deficits if the diagnosis is delayed. Most cases of spina bifida and other neural tube defects result from maternal folate and/or cobalamin insufficiency in the periconceptual period.

Importin 13 regulates nuclear import of the glucocorticoid receptor in airway epithelial cells.

Antiinflammatory effects of glucocorticoids are critical to treatment of airway inflammation in such common disorders as asthma. There is considerable variation in responsiveness to glucocorticoid, and prolonged exposure can result in glucocorticoid resistance. We cloned LGL2, a glucocorticoid-inducible gene in fetal rat lung.

Light-induced retinopathy: comparing adult and juvenile rats.

Purpose: To investigate the effect of chronic exposure to a bright, luminous environment, starting at the opening of the eyes, on the retinal structure and function of the suckling rat.

Methods: Juvenile Sprague-Dawley rats were exposed to 10,000 lux, for varying lengths of time between postnatal day (P)14 and P34. Results were compared with those obtained from adult rats exposed to the same light intensity and for the same duration.

Maternal folate deficiency affects proliferation, but not apoptosis, in embryonic mouse heart.

Low dietary folate and deficiency of methylenetetrahydrofolate reductase (Mthfr) were reported to increase the risk for congenital heart defects, but contributory mechanisms have not been elucidated. Because low folate and absent MTHFR activity were shown to affect proliferation and apoptosis in developing neural tissue, we examined these processes in the myocardium of embryos from Mthfr +/+ and Mthfr +/- mice fed control diets (CD) or folic acid-deficient diets (FADD). Mice consumed the designated diets for 8 wk, from weaning and through pregnancy until they were killed.

Structural and functional consequences of trolox C treatment in the rat model of postnatal hyperoxia.

Purpose: Previous studies have shown that newborn rats exposed to hyperoxia within the first 2 weeks of life develop vasculopathy in addition to permanent changes in retinal structure and function. It has also been suggested that free radicals may be the source of these pathologic effects. Trolox C, a water-soluble analogue of vitamin E, was previously shown to limit the vascular consequences of exposure to postnatal hyperoxia.

Gamete imprinting: setting epigenetic patterns for the next generation.

The acquisition of genomic DNA methylation patterns, including those important for development, begins in the germ line. In particular, imprinted genes are differentially marked in the developing male and female germ cells to ensure parent-of-origin-specific expression in the offspring. Abnormalities in imprints are associated with perturbations in growth, placental function, neurobehavioural processes and carcinogenesis.

Impact of methylenetetrahydrofolate reductase deficiency and low dietary folate on the development of neural tube defects in splotch mice.

Background: The etiology of neural tube defects (NTDs) is multifactorial, with environmental and genetic determinants. Folate supplementation prevents the majority of NTDs, and a polymorphism in methylenetetrahydrofolate reductase (MTHFR) has become recognized as a genetic risk factor. The mechanisms by which folate affects NTD development are unclear.

The photopic ERG of the albino guinea pig (Cavia porcellus): a model of the human photopic ERG.

Altricial rodents such as rats and mice are probably the most widely used animal model in the electroretinogram (ERG) literature. However, while the scotopic responses of these rodents share obvious similarities with that of humans, their photopic electroretinograms are strikingly different. For instance, the photopic ERGs of rats and mice include, when measurable, a minimal a-wave, while the b-wave is of much larger amplitude than that of humans.

Maternal methylenetetrahydrofolate reductase deficiency and low dietary folate lead to adverse reproductive outcomes and congenital heart defects in mice.

Background: Genetic or nutritional disturbances in folate metabolism may affect embryonic development because of the critical role of folate in nucleotide synthesis and methylation reactions. The possible role of a mild deficiency in methylenetetrahydrofolate reductase (MTHFR) and low dietary folate in pregnancy outcomes and heart morphogenesis requires further investigation.

Objective: We investigated the effect of mild MTHFR deficiency, low dietary folate, or both on resorption rates, on length and weight, and on the incidence of heart malformations in murine embryos.

Platelet-activating factor antagonists decrease follicular dendritic-cell stimulation of human B lymphocytes.

Both B-lymphoblastoid cell lines and tonsillar B lymphocytes express receptors for platelet-activating factor (PAF). In lymph node germinal centres, B lymphocytes interact with follicular dendritic cells (FDCs), which present antigen-containing immune complexes to B lymphocytes. FDCs have phenotypic features that are similar to those of stromal cells and monocytes and may therefore be a source of lipid mediators.

Prolonged and unsoothable crying bouts in infants with and without colic.

ABSTRACT.: The authors sought to determine which features of early distress were "excessive" and specific to the first months of life as described by diary recordings. In a short-term, longitudinal, controlled study, total daily amount, frequency, and bout duration of fussing, crying, and unsoothable crying were derived from validated diaries kept by parents of infants with and without diary-defined colic at 6 weeks and 5 months recruited from primary pediatrics practices.

Accumulation of methotrexate and methotrexate polyglutamates in lymphoblasts and treatment outcome in children with B-progenitor-cell acute lymphoblastic leukemia: a Pediatric Oncology Group study.

We reported that children with B-progenitor-cell acute lymphoblastic leukemia (BpALL) treated in the early 1980s whose lymphoblasts accumulated high levels of methotrexate (MTX) and of methotrexate polyglutamates (MTXPGs) in vitro had an improved 5-year event-free survival (EFS) (65% (standard error (s.e.) 12%) vs 22% (s.

Reproductive epigenetics.

Epigenetics refers to covalent modifications of DNA and core histones that regulate gene activity without altering DNA sequence. To date, the best-characterized DNA modification associated with the modulation of gene activity is methylation of cytosine residues within CpG dinucleotides. Human disorders associated with epigenetic abnormalities include rare imprinting diseases, molar pregnancies, and childhood cancers.

Potential significance of genomic imprinting defects for reproduction and assisted reproductive technology.

Recent studies suggest a possible link between human assisted reproductive technology and genomic imprinting disorders. Assisted reproductive technology includes the isolation, handling and culture of gametes and early embryos at times when imprinted genes are likely to be particularly vulnerable to external influences. Evidence of sex-specific differences in imprint acquisition suggests that male and female germ cells may be susceptible to perturbations in imprinted genes at specific prenatal and postnatal stages.

5-aza-2'-deoxycytidine induces alterations in murine spermatogenesis and pregnancy outcome.

Because of the ability of cytidine analogues, such as 5-aza-2'-deoxycytidine, to incorporate into DNA and lead to decreases in DNA methylation, there has recently been renewed interest in using these drugs in anticancer therapy. To determine the effects of paternal 5-aza-2'-deoxycytidine treatment on spermatogenesis and progeny outcome in the mouse and whether effects are modulated by decreased levels of the predominant DNA methyltransferase, DNMT1, adult Dnmt1(+/+) and Dnmt1-deficient (Dnmt1(c/+)) male mice were treated with 5-aza-2'-deoxycytidine for 7 weeks, which resulted in dose-dependent decreases in testicular weight, an increase in histological abnormalities, and a decline in sperm counts, with no apparent effect on androgen status. Testes of Dnmt1(c/+) mice, however, were less severely affected by 5-aza-2'-deoxycytidine than were those of wild-type mice.

Spontaneous occurrence of a potentially night blinding disorder in guinea pigs.

Several hereditary retinal disorders such as retinitis pigmentosa and congenital stationary night blindness compromise, sometimes exclusively, the activity of the rod pathway. Unfortunately, there are few animal models of these disorders that could help us better understand the pathophysiological processes involved. The purpose of this report is to present a pedigree of guinea pigs where, as a result of a consanguineous mating and subsequent selective breeding, we developed a new and naturally occurring animal model of a rod disorder.

Nucleocytoplasmic shuttling of lgl2 is developmentally regulated in fetal lung.

To investigate molecular mechanisms of lung organogenesis, we searched for glucocorticoid-inducible genes in developing lung. We cloned LGL2, a developmentally and hormonally regulated gene in fetal lung (Zhang, C., N.

Common variant in betaine-homocysteine methyltransferase (BHMT) and risk for spina bifida.

Neural tube defects (NTD) are common malformations resulting from incomplete closure of the neural tube in the first month after conception. Since genetic deficiencies in folate-dependent homocysteine metabolism have been identified in NTD families, we investigated a common variant in betaine-homocysteine methyltransferase (BHMT), 742G-->A (R239Q), as a genetic modifier of NTD risk. Genotypes, nutrient levels, and plasma total homocysteine (tHcy) were assessed in 54 patients with spina bifida, 57 mothers of patients, 93 control children, and 86 mothers of controls.

Structure and function of disease-causing missense mutations in the PHEX gene.

The PHEX gene that is mutated in patients with X-linked hypophosphatemia (XLH) encodes a protein homologous to the M13 family of zinc metallopeptidases. The present study was undertaken to assess the impact of nine PHEX missense mutations on cellular trafficking, endopeptidase activity, and protein conformation. Secreted forms of wild-type and mutant PHEX proteins were generated by PCR mutagenesis; these included C85R, D237G, Y317F, G579R, G579V, S711R, A720T, and F731Y identified in XLH patients, and E581V, which in neutral endopeptidase 24.