Halogenated Phenylpyridines Possessing Chemo-Selectivity for Diverse Molecular Architectures.

Pentafluoropyridine was used as a molecular building block for the installation of aryl bromides, affording a series of multisubstituted halogenated arenes. This operationally simplistic methodology offers precise regioselectivity, ease of scalability, and high purity. F Nuclear magnetic resonance (NMR) served as a key diagnostic tool for structural characterization, given the sensitivity with various aryl bromine substitutions on the fluorinated pyridine ring.

Which Risk Factors for Child Maltreatment Predict Mothers' Enrollment in a Parenting Support Program?

Parenting support programs are an effective means of preventing child maltreatment. However, these programs are often criticized for their limited ability to enroll and engage the parents who need them most. The present study aimed to determine which risk factors associated with child maltreatment predicted mothers' enrollment in the Triple P-Positive Parenting Program in Quebec.

Spatial and temporal variations of a saxitoxin analogue (LWTX-1) in Lyngbya wollei (Cyanobacteria) mats in the St. Lawrence River (Québec, Canada).

The concentration of the saxitoxin analogue LWTX-1 was quantified in samples of the benthic filamentous cyanobacterium Lyngbya wollei (Farlow ex Gomont) Speziale and Dyck collected in two fluvial lakes of the St. Lawrence River (Canada) over the 2006-2013 period. The study was aimed at documenting the spatial (between fluvial lakes, between sites within each lake) and temporal (inter-annual, monthly) variations of toxin concentration in relation with hydrological (water level), physical (water temperature, conductivity, transparency), chemical (nutrients in overlying water) and biological (L.

Inactivation dates of the human and guinea pig vitamin C genes.

The capacity to biosynthesize ascorbic acid has been lost in a number of species including primates, guinea pigs, teleost fishes, bats, and birds. This inability results from mutations in the GLO gene coding for L-gulono-γ-lactone oxidase, the enzyme responsible for catalyzing the last step in the vitamin C biosynthetic pathway. We analyzed available primate and rodent GLO gene sequences to determine their evolutionary history.

Potential value of fetal echocardiography in the differential diagnosis of twin pregnancy with presence of polyhydramnios-oligohydramnios syndrome.

Objective: Our purpose was to establish whether index values of cardiac performance could discriminate between the twin-twin transfusion syndrome and placental insufficiency as the etiology of the polyhydramnios-oligohydramnios sequence in monochorionic diamniotic twins.

Study Design: Thirteen monochorionic diamniotic twin pregnancies with ultrasonographic evidence of polyhydramnios-oligohydramnios sequence had a complete echocardiography. The etiology was confirmed postnatally: placental insufficiency in eight pairs and the twin-twin transfusion syndrome in five.

Flow cytometric evaluation of leukocyte subpopulations in the follicular fluids of infertile patients.

Objectives: To evaluate the leukocyte subpopulations present in follicular fluid (FF) of infertile patients undergoing IVF-ET for tubal factor, idiopathic infertility, and endometriosis.

Patients: Sixty patients undergoing IVF-ET with a tubal factor diagnosis (n = 35), idiopathic infertility (n = 13), and endometriosis (n = 12) had their subpopulations of FF leukocytes analyzed by flow cytometry.

Main Outcome Measure: Nonblood-contaminated samples of FF were collected under sterile conditions and centrifuged.

Endometrial T, B, and NK cells in patients with recurrent spontaneous abortion. Altered profile and pregnancy outcome.

Several lines of evidence indicate that immunologic effectors, particularly suppressor T cells and NK cells, may play a role in the pathogenesis of idiopathic repetitive abortions. To investigate the involvement of these immune cell populations, we determined the immunophenotypic characteristics of endometrial leukocytes from nonpregnant recurrent aborters. Habitual aborters with a negative investigation underwent an endometrial biopsy during their secretory phase and were followed prospectively to assess clinical outcome.

Flow-cytometric characterization of hematopoietic cells in non-pregnant human endometrium.

Problem: Immunologic evaluation and quantitation of hematopoietic cells in human endometrium has been difficult to perform, particularly in nonpregnant subjects. In this study, we describe a method for the flow-cytometric characterization of hematopoietic cells present in the endometrium of non-pregnant women.

Method: Endometrial biopsy samples from normal donors were first mechanically disrupted and filtered to generate a single-cell suspension of leukocyte-enriched endometrial cells.

Immunolocalization of freezing-tolerance-associated proteins in the cytoplasm and nucleoplasm of wheat crown tissues.

A protein family associated with the development of freezing tolerance in wheat has been identified. This protein family is Gramineae-specific and coordinately regulated by low temperature. Antibodies directed against the 50 kDa (WCS120) protein recognize at least 5 members of this family.

Decreased interleukin-2 receptor and cell cycle changes in murine lymphocytes exposed in vitro to low doses of cadmium chloride.

Relationships between in vitro cadmium-related cell cytotoxicity, ultrastructural changes and altered cell cycle were determined at 21-72 h after mitogenic stimulation of C57BL/6 mouse spleen lymphocytes with concanavalin A (Con A). Relatively low doses, 0.6-10 microM cadmium (Cd), added at 4 h after the mitogen activation, induced a significant cell cytotoxicity and reduced the lymphoblastic activity of the cells.

Immunocytochemical evidence for a nuclear and a cytoplasmic O6-methylguanine repair mechanism in cultured rat hepatocytes.

The localization of DNA and RNA adducts was studied at the ultrastructural level using antibodies directed against O6-metG and the protein A-gold technique. Primary rat hepatocyte cultures were exposed for 2-24 h to 5 mM N-nitrosodimethylamine (NDMA) or 0.1 mM N-methyl-N'-nitro-N-nitrosoguanidine (MNNG).

Effect of follicular fluid supplementation on the in vitro development of human pre-embryos.

Objective: To evaluate the value of supplementing a standard culture medium with 10% heat-inactivated mature follicular fluid (FF).

Design: Prospective randomized study evaluating the in vitro development of nontransferred, nonfrozen human pre-embryos in three culture conditions from day 3 to day 8 postfertilization. Preliminary evaluation by RIA and electrophoresis of factors responsible for these results.

O6-methylguanine-DNA adducts in rat lymphocytes after in vivo exposure to N-nitrosodimethylamine (NDMA).

A non-invasive approach in immunopathological risk assessment was applied for analysis of the in vivo formation of DNA adducts. DNA methylation was studied in peripheral blood lymphocytes (PBLs) collected from Sprague-Dawley rats exposed to a single dose (75 mg/kg b.w.

Embryonic resistance to tumour necrosis factor-alpha mediated cytotoxicity: novel mechanism underlying maternal immunological tolerance to the fetal allograft.

The cytokine tumour necrosis factor-alpha (TNF alpha) has been postulated to play an essential role in the cytotoxic activity of cell-mediated immunity against allogenic or tumour cells invading the host. Several tumour cell lines, however, are resistant to TNF mediated cytotoxicity and respond paradoxically by cellular proliferation and by autocrine secretion of TNF alpha. In view of the metastatic character of the mammalian embryo, the aim of this study was to assess the potential of murine embryos to secrete TNF alpha in vitro, to express TNF receptors and to resist TNF alpha mediated cytotoxicity during their in-vitro development to the blastocyst stage.

Recovery potential of hepatocytes from inhibition of albumin secretion by cadmium.

The aim of this study was to examine albumin production, a typical liver-specific function, in hepatocytes treated with Cd and to examine the reversibility of the perturbations induced by the toxic metal. Cultures of freshly isolated rat hepatocytes were exposed to increasing amounts of Cd in modified Leibowitz L-15 medium for 20 h; the cells were then allowed to recover by further incubation in Cd-free medium for an additional period of 20 h. The levels of albumin secreted into the extracellular medium were determined by enzyme-linked immunosorbent assay and were found to be reduced by Cd in a concentration-dependent fashion over the first 20 h.

Mercuric chloride affects protein secretion in rat primary hepatocyte cultures: a biochemical ultrastructural, and gold immunocytochemical study.

The toxicity of mercury on hepatocytes was studied at the ultrastructural, biochemical, and immunocytochemical levels. Albumin metabolism was examined because it is a representative liver-specific function. A novel cytochemical method using the protein A-gold technique for the in situ localization of albumin in hepatocyte cultures was applied.

Effect of lysoplatelet-activating factor on human sperm fertilizing ability.

Objective: To evaluate the penetration rates in the hamster zona-free oocyte sperm penetration assay (SPA) after exposure of spermatozoa to lysoplatelet-activating factor (LPAF) and lysophosphatidyl choline (LPC).

Design: Washed human spermatozoa were exposed to 100 microM of LPAF or LPC, followed by the assessment of their fertilizing ability using the SPA. The percentage of penetration, the sperm binding in the SPA, the percentage of motile spermatozoa, and the acrosome reaction rates were quantified.

Colloidal gold ultraimmunocytochemical localization of DNA and RNA adducts in rat hepatocytes.

The localization of DNA and RNA adducts was studied at the ultrastructural level using antibodies directed against O6-methylguanine (O6-metG) and the protein A-gold technique. Primary rat hepatocyte cultures were exposed for 2 h to 5 mM N-nitrosodimethylamine (NDMA). In NDMA-treated cells, the O6-metG-induced immunoreactive sites do not appear at random but seem to be concentrated in the nucleus, and in the cytoplasm, in areas rich in rough endoplasmic reticulum (RER) elements.

Contractile proteins in podocytes: immunocytochemical localization of actin and alpha-actinin in normal and nephrotic rat kidneys.

Actin and alpha-actinin immunoreactive sites have been localized at the electron microscope level by the protein A-gold immunocytochemical technique in podocytes of normal and nephrotic rat renal tissues. In normal renal glomeruli, fibrillar networks located in the core of foot processes or bundles of microfilaments interconnecting them were found to be labelled for these two cytoskeletal proteins. On the other hand, in nephrotic renal glomeruli, concomitant with the loss of podocytic foot processes a reorganization of the podocytic cytoskeleton and a concentration of some of its elements into thick uniform bands was observed.

Phalloidin-gold complexes: a new tool for ultrastructural localization of F-actin.

We used a phalloidin-gold complex to study the distribution of F-actin in the myxamoebae and macroplasmodia of the slime mold Physarum polycephalum. After incubation of Lowicryl- or Quetol-embedded specimens with this complex, significantly different labeling intensities were found over the various cytoplasmic and nuclear regions of the cells. The nucleoplasm was the most heavily labeled cell compartment, followed in decreasing order of labeling intensity by the cytoplasm, the nucleolus, and the chromocenters.

Interaction of (dien)Pd(II) with cytidine and cytidine 5'-monophosphate. Influence of the phosphate group on the kinetics and mechanism.

The kinetics and the equilibrium of (dien)PdCl+ interaction with cytidine (C) and cytidine 5'-monophosphate (CMP) were studied by spectrophotometry and by stopped-flow methods. In both cases, the mechanism implies a (dien)Pd(H2O)2+ intermediate with a significant contribution of the solvent path at low chloride concentrations. With CMP, the rate is affected due to the addition of a mechanistic path via an intermediate formed between (dien)Pd(II) and the phosphate group of CMP.