Neonatal Outcomes After Delivery in Water.

OBJECTIVE: To assess neonatal intensive care unit (NICU) admissions and neonatal outcomes after water birth or land birth in an alternative birthing center. METHODS: We conducted a prospective observational study of preselected low-risk parturients separated into three groups depending on their location for labor and delivery: land-land, water-land, and water-water. Delivery outcomes, labor length, maternal pain assessment, need for newborn resuscitation, and NICU admission and diagnoses were collected. The primary outcome was admission to the NICU. RESULTS: There were 2,077 total deliveries from April 2015 to December 2019, consisting of 458 land-land deliveries, 730 water-land deliveries, and 889 water-water deliveries. The rate of NICU admission was 2.8% (95% CI 1.5-4.8%) for land-land deliveries, 4.1% (2.8-5.8%) for water-land deliveries, and 2.0% (1.2-3.2%) for water-water deliveries. A post hoc power analysis revealed a 70% power to detect a 2.1% difference in NICU admissions between the water-land and water-water groups. CONCLUSION: In this cohort of low-risk pregnant women, births in water and on land were associated with similar rates of admission to the NICU.

Ablation of an Ovarian Tumor Family Deubiquitinase Exposes the Underlying Regulation Governing the Plasticity of Cell Cycle Progression in Toxoplasma gondii.

The Toxoplasma genome encodes the capacity for distinct architectures underlying cell cycle progression in a life cycle stage-dependent manner. Replication in intermediate hosts occurs by endodyogeny, whereas a hybrid of schizogony and endopolygeny occurs in the gut of the definitive feline host. Here, we characterize the consequence of the loss of a cell cycle-regulated ovarian tumor (OTU family) deubiquitinase, OTUD3A of Toxoplasma gondii (TgOTUD3A; TGGT1_258780), in T. gondii tachyzoites. Rather than the mutation being detrimental, mutant parasites exhibited a fitness advantage, outcompeting the wild type. This phenotype was due to roughly one-third of TgOTUD3A-knockout (TgOTUD3A-KO) tachyzoites exhibiting deviations from endodyogeny by employing replication strategies that produced 3, 4, or 5 viable progeny within a gravid mother instead of the usual 2. We established the mechanistic basis underlying these altered replication strategies to be a dysregulation of centrosome duplication, causing a transient loss of stoichiometry between the inner and outer cores that resulted in a failure to terminate S phase at the attainment of 2N ploidy and/or the decoupling of mitosis and cytokinesis. The resulting dysregulation manifested as deviations in the normal transitions from S phase to mitosis (S/M) (endopolygeny-like) or M phase to cytokinesis (M/C) (schizogony-like). Notably, these imbalances are corrected prior to cytokinesis, resulting in the generation of normal progeny. Our findings suggest that decisions regarding the utilization of specific cell cycle architectures are controlled by a ubiquitin-mediated mechanism that is dependent on the absolute threshold levels of an as-yet-unknown target(s). Analysis of the TgOTUD3A-KO mutant provides new insights into mechanisms underlying the plasticity of apicomplexan cell cycle architecture.IMPORTANCE Replication by Toxoplasma gondii can occur by 3 distinct cell cycle architectures. Endodyogeny is used by asexual stages, while a hybrid of schizogony and endopolygeny is used by merozoites in the definitive feline host. Here, we establish that the disruption of an ovarian-tumor (OTU) family deubiquitinase, TgOTUD3A, in tachyzoites results in dysregulation of the mechanism controlling the selection of replication strategy in a subset of parasites. The mechanistic basis for these altered cell cycles lies in the unique biology of the bipartite centrosome that is associated with the transient loss of stoichiometry between the inner and outer centrosome cores in the TgOTUD3A-KO mutant. This highlights the importance of ubiquitin-mediated regulation in the transition from the nuclear to the budding phases of the cell cycle and provides new mechanistic insights into the regulation of the organization of the apicomplexan cell cycle.

Juvenile play experience does not affect nicotine sensitization and voluntary consumption of nicotine in adult rats.

Juvenile play experiences promote behavioral flexibility in rats. If other early positive experiences, such as tactile stimulation, are given prior to exposure to psychostimulants, the behavioral response to the drug is attenuated. The objective of the present study was to determine if the experience of juvenile play behavior would attenuate the response to nicotine. Two experiments were conducted: (1) behavioral sensitization to nicotine exposure, and (2) voluntary consumption of nicotine. For both experiments, rats were reared either with three same-sex peers (play group) or one adult (no play group) during their juvenile period. Then, as adults, half of each group was exposed to repeated injections of nicotine and the other half to saline. Prior play experience had no effect on behavioral sensitization or on voluntary consumption of nicotine. It remains to be determined whether juvenile experience with play influences the rewarding properties of nicotine in social contexts as adults.

Chemical vapor detection using single-walled carbon nanotubes.

Single-walled carbon nanotubes possess unique properties that make them a potentially ideal material for chemical sensing. However, their extremely small size also presents technical challenges for realizing a practical sensor technology. In this tutorial review we explore the transduction physics by which the presence of molecular adsorbates is converted into a measurable electronic signal, and we identify solutions to the problems such as nanotube device fabrication and large, low-frequency noise that have inhibited commercial sensor development. Finally, we examine strategies to provide the necessary chemical specificity to realize a nanotube-based detection system for trace-level chemical vapor detection.

Chemical detection with a single-walled carbon nanotube capacitor.

We show that the capacitance of single-walled carbon nanotubes (SWNTs) is highly sensitive to a broad class of chemical vapors and that this transduction mechanism can form the basis for a fast, low-power sorption-based chemical sensor. In the presence of a dilute chemical vapor, molecular adsorbates are polarized by the fringing electric fields radiating from the surface of a SWNT electrode, which causes an increase in its capacitance. We use this effect to construct a high-performance chemical sensor by thinly coating the SWNTs with chemoselective materials that provide a large, class-specific gain to the capacitance response. Such SWNT chemicapacitors are fast, highly sensitive, and completely reversible.

Subcellular localization of nardilysin during mouse oocyte maturation.

We have previously shown that the peptidase, nardilysin, contains a bipartite nuclear localization signal that permits the enzyme to cycle between the nucleus and cytoplasm. In the present study, we report that nardilysin accumulates in the nucleus of an oocyte as a function of its maturation. Nardilysin is predominantly localized in the cytoplasm of an oocyte when initially placed into culture. The enzyme starts to accumulate in the nucleus within 30 min of in vitro culture. After 3 h, nardilysin is found as a spherical structure surrounded by condensed chromosomal DNA. After 18 h of in vitro culture, it co-localizes with beta-tubulin at the spindle apparatus. Cilostamide, a phosphodiesterase 3A inhibitor that inhibits meiosis, blocks accumulation of nuclear nardilysin. This finding demonstrates that the nuclear entry of nardilysin is tightly controlled in the oocyte. Taken together, these experiments strongly suggest a role for nardilysin in meiosis through its dynamic translocation from cytosol to nucleus, and then to the spindle apparatus.

Act1, a negative regulator in CD40- and BAFF-mediated B cell survival.

TNF receptor (TNFR) superfamily members, CD40, and BAFFR play critical roles in B cell survival and differentiation. Genetic deficiency in a novel adaptor molecule, Act1, for CD40 and BAFF results in a dramatic increase in peripheral B cells, which culminates in lymphadenopathy and splenomegaly, hypergammaglobulinemia, and autoantibodies. While the B cell-specific Act1 knockout mice displayed a similar phenotype with less severity, the pathology of the Act1-deficient mice was mostly blocked in CD40-Act1 and BAFF-Act1 double knockout mice. CD40- and BAFF-mediated survival is significantly increased in Act1-deficent B cells, with stronger IkappaB phosphorylation, processing of NF-kappaB2 (p100/p52), and activation of JNK, ERK, and p38 pathways, indicating that Act1 negatively regulates CD40- and BAFF-mediated signaling events. These findings demonstrate that Act1 plays an important role in the homeostasis of B cells by attenuating CD40 and BAFFR signaling.

Arsenic and heavy metal contamination of vegetables grown in Samta village, Bangladesh.

Drinking of arsenic (As) contaminated well water has become a serious threat to the health of many millions in Bangladesh. However, the implications of contamination of agricultural soils from long-term irrigation with As-contaminated groundwater for phyto-accumulation in food crops, and thence dietary exposure to As, and other metals, has not been assessed previously in Bangladesh. Various vegetables were sampled in Samta village in the Jessore district of Bangladesh, and screened for As, Cd, Pb, Cu and Zn by inductively coupled plasma emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). These local food products are the basis of human nutrition in this region and of great relevance to human health. The results revealed that the individual vegetables containing the highest mean As concentrations microg x g(-1)) are snake gourd (0.489), ghotkol (0.446), taro (0.440), green papaya (0.389), elephant foot (0.338) and Bottle ground leaf (0.306), respectively. The As concentration in fleshy vegetable material is low. In general, the data show the potential for some vegetables to accumulate heavy metals with concentrations of Pb greater than Cd. Some vegetables such as bottle ground leaf, ghotkol, taro, eddoe and elephant foot had much higher concentrations of Pb. Other leafy and root vegetables, contained higher concentrations of Zn and Cu. Bioconcentration factors (BCF) values, based on dry weight, were below 1 for all metals. In most cases, BCF values decreased with increasing metal concentrations in the soil. From the heavily As-contaminated village in Samta, BCF values for As in ladies finger, potato, ash gourd, brinjal, green papaya, ghotkol and snake gourd were 0.001, 0.006, 0.006, 0.014, 0.030, 0.034 and 0.038, respectively. Considering the average daily intake of fresh vegetables per person per day is only 130 g, all the vegetables grown at Samta had Pb concentrations that would be a health hazard for human consumption. Although the total As in the vegetables was less than the recommended maximum intake of As, it still provides a significant additional source of As in the diet.

A comparison of trace element concentrations in cultured and wild carp (Cyprinus carpio) of Lake Kasumigaura, Japan.

The concentrations of 13 elements were determined in the muscle, liver, intestine, kidney, and gonads of cultured and wild carp caught at two sites in Lake Kasumigaura, Japan, between September 1994 and September 1995. Despite having a reputation for being heavily polluted, the carp were not heavily burdened with metals. Our results suggest that despite their dietary differences, the wild and cultured fish were accumulating and distributing metals in the same manner and that aquaculture practices are not increasing metal concentrations in these fish. Metal concentrations were lowest in muscle, and did not exceed established quality standards for fish. The differences in metal concentrations between cultivated and wild carp are negligible and should pose no health problems for consumers of either type of fish.

Defective CD19-dependent signaling in B-1a and B-1b B lymphocyte subpopulations.

Peritoneal and pleural cavities in mice and humans contain a unique population of B-lymphocytes called B-1 cells that are defective in B cell antigen receptor (BCR) signaling but have an increased propensity to produce autoantibodies. Several molecules such as Btk, Vav, and CD19 known to be important for BCR signaling have been shown to be critical for the development of B-1 cells from undefined precursors. Here we demonstrate that B-1 cell unresponsiveness to BCR cross-linking is in part due to defective signaling through CD19, a molecule known to modulate signaling thresholds in B cells. The defective CD19 signaling is manifested in reduced synergy between mIgM and CD19 to stimulate calcium mobilization in B-1 cells. BCR induced tyrosine phosphorylation of CD19 was transient in B-1 cells while it was prolonged in splenic B-2 cells. In both B-1 and B-2 cells BCR cross-linking induced a modest increase of CD19 associated Lyn, a Src family protein tyrosine kinase (PTK) thought to be important for CD19 phosphorylation. However, the tyrosine phosphorylated CD19 in B-1 cells binds less phosphatidylinositol 3-kinase (PI3-K) compared to B-2 cells. Most interestingly, we find that Vav-1 and Vav-2, proteins thought to be critical for CD19 signal transduction, are severely reduced in B-1 cells resulting in a complete absence of any CD19 associated Vav. Also we showed that both B-1a and B-1b B cells failed to proliferate in response to BCR cross-linking which in part appears to be due to defects in CD19 mediated amplification of BCR induced calcium mobilization.

In vitro effect of arsenical compounds on glutathione-related enzymes.

The mechanism of arsenic toxicity is believed to be due to the ability of arsenite (As(III)) to bind protein thiols. Glutathione (GSH) is the most abundant cellular thiol, and both GSH and GSH-related enzymes are important antioxidants that play an important role in the detoxification of arsenic and other carcinogens. The effect of arsenic on the activity of a variety of enzymes that use GSH has been determined using purified preparations of glutathione reductase (GR) from yeast and bovine glutathione peroxidase (GPx) and equine glutathione S-transferase (GST). The effect on enzyme activity of increasing concentrations (from 1 microM to 100 mM) of commercial sodium arsenite (As(III)) and sodium arsenate (As(V)) and a prepared arsenic(III)-glutathione complex [As(III)(GS)(3)] and methylarsenous diiodide (CH(3)As(III)) has been examined. GR, GPx, and GST are not sensitive to As(V) (IC(50) > 50 mM), and none of the enzymes are inhibited or activated by physiologically relevant concentrations of As(III), As(III)(GS)(3), or CH(3)As(III), although CH(3)As(III) is the most potent inhibitor (0.3 mM < IC(50) < 1.5 mM). GPx is the most sensitive to arsenic treatment and GST the least. Our results do not implicate a direct interaction of As with the glutathione-related enzymes, GR, GPx, and GST, in the mechanism of arsenic toxicity. CH(3)As(III) is the most effective inhibitor, but it is unclear whether this product of arsenic metabolism is produced at a sufficiently high concentration in critical target tissues to play a major role in either arsenic toxicity or carcinogenesis.

Cutting edge: recruitment of the CD19/CD21 coreceptor to B cell antigen receptor is required for antigen-mediated expression of Bcl-2 by resting and cycling hen egg lysozyme transgenic B cells.

Recruitment of the CD19/CD21 coreceptor is thought to lower the threshold for effective signaling through the B cell Ag receptor. We provide evidence supporting a second role for coreceptor recruitment, and that is to enhance the survival/proliferative potential of the responding B cells. We show that B cell Ag receptor signaling in the absence of coreceptor recruitment induces cellular accumulation of the anti-apoptotic protein Bcl-xL, whereas CD19-mediated signals are required for Bcl-2 accumulation. The expression of both anti-apoptotic proteins correlates with the enhanced responsiveness of both resting and cycling B cells to growth-promoting signals delivered through CD40. These results provide further evidence for the necessity of coreceptor recruitment during Ag-dependent B cell activation and indicate that Ags derived from inflammatory sites function as better thymus-dependent Ags than their counterparts not coated with complement fragments.

CD40-mediated induction of p21 accumulation in resting and cycling B cells.

The accumulation of G1 cell cycle-related proteins by resting or cycling B cells stimulated with B cell antigen receptor (BCR)- and T helper (Th) cell-derived signals is documented. Resting B cells constitutively express cyclin dependent kinase (cdk)4, cdk2 and the cyclin dependent kinase inhibitor (CKI), p27. The initiation of optimal proliferation with F(ab')2 anti-mu plus paraformaldehyde-fixed CD40 ligand-baculovirus-infected Sf9 cells (CD40L/Sf9 cells) increases accumulation of both cdk4 and cdk2 while decreasing p27 levels. B cells express cyclin D2 early during cycle progression, while cyclin D3 and E are not expressed until 18 h poststimulation and cyclin A by 24 h poststimulation. Cycling B cells express heightened levels of all these cyclins and cdks. Although neither BCR- nor CD40-mediated signals appreciably alter cycling B cell accumulation of cyclins D2, cdk4 and cdk2, the absence of BCR-derived signals results in a decreased accumulation of cyclins D3 and E. Finally, CD40-mediated signals induce resting B cells to accumulate the CKI, p21, while cycling B cells require both BCR- and CD40-mediated signals to maintain increased expression of p21. Thus, a Th cell-derived signal may impact upon both resting and cycling B cell cycle progression, at least in part, by regulating the accumulation of p21. The functional consequences of p21 accumulation as cells enter and move through the cell cycle are discussed.

Arsenic toxicity is enzyme specific and its affects on ligation are not caused by the direct inhibition of DNA repair enzymes.

The molecular mechanism of arsenic toxicity is believed to be due to the ability of arsenite [As(III)] to bind protein thiols. Numerous studies have shown that arsenic is cytotoxic at micromolar concentrations. Micromolar As can also induce chromosomal damage and inhibit DNA repair. The mechanism of arsenic-induced genotoxicity is very important because arsenic is a human carcinogen, but not a mutagen, and there is a need to establish recommendations for safe levels of As in the environment. We have measured the dose-response for arsenic inhibition of several purified human DNA repair enzymes, including DNA polymerase beta, DNA ligase I and DNA ligase III and have found that most enzymes, even those with critical SH groups, are very insensitive to As. Many repair enzymes are activated by millimolar concentrations of As(III) and/or As(V). Only pyruvate dehydrogenase, one of eight purified enzymes examined so far, is inhibited by micromolar arsenic. In contrast to the purified enzymes, treatment of human cells in culture with micromolar arsenic produces a significant dose-dependent decrease in DNA ligase activity in nuclear extracts from the treated cells. However, the ligase activity in extracts from untreated cells is no more sensitive to arsenic than the purified enzymes. Our results show that direct enzyme inhibition is not a common toxic effect of As and that only a few sensitive enzymes are responsible for arsenic-induced cellular toxicity. Thus, arsenic-induced co-mutagenesis and inhibition of DNA repair is probably not the result of direct enzyme inhibition, but may be an indirect effect caused by As-induced changes in cellular redox levels or alterations in signal transduction pathways and consequent changes in gene expression.

Patients with stable chronic obstructive pulmonary disease can safely undergo intravenous dipyridamole thallium-201 imaging.

BACKGROUND: Patients with chronic obstructive pulmonary disease are usually excluded from intravenous dipyridamole thallium-201 testing. We developed a nurse-administered protocol to screen and pretreat patients so they could be safely tested. METHODS AND RESULTS: We prospectively screened patients referred for intravenous dipyridamole thallium testing and retrospectively reviewed a comparison group of patients who had undergone intravenous dipyridamole testing before our bronchospasm protocol. We studied 492 consecutive patients referred for intravenous dipyridamole thallium testing, separating those with complete data (n = 451) into two groups: group A (n = 72), patients assessed to be at risk for intravenous dipyridamole-induced bronchospasm who received our bronchospasm treatment protocol; and group B (n = 379), patients assessed to be free of risk, who did not receive our bronchospasm protocol. Group C (n = 89) was a retrospective comparison group of patients who had undergone intravenous dipyridamole testing before initiation of the protocol. Patients were considered at risk for an adverse event if any of the following were present: peak flow < or =400 ml at the time of the test (spirometry by nurse) that increased to >400 ml after bronchodilator treatment, wheezing audible with stethoscope, history of chronic obstructive pulmonary disease or asthma or dyspnea on exertion at less than four blocks, or resting respiratory rate >18 breaths/min. The test was considered contraindicated if resting oxygen saturation was <85%, respiratory rate < or =36 breaths/min, or peak flow measured by peak flowmeter <400 ml after bronchodilator inhalant (albuterol or metaproterenol sulfate by spacer) at a dose of up to six puffs. One minute after injections of thallium-201, patients at risk were given 50 mg aminophylline by slow intravenous injection. We looked for major and minor adverse effects and divided them into three categories: (1) minor events (transient headache, abdominal discomfort, or nausea), wheezing (audible by stethoscope but without marked respiratory distress), (2) marked events (severe bronchospasm or severe ischemia defined as wheezing audible with or without stethoscope, respiratory rate >20 breaths/min or increased by 10 from pretest evaluation, oxygen desaturation to <90%, hypoventilation [reduced respiratory rate with decreased mental status], respiratory arrest, chest pain, horizontal ST-segment depression > or =1 mm on the electrocardiogram in any lead, symptomatic hypotension), or (3) other intravenous dipyridamole-induced side effects (persistent headache, dizziness, flushing, nausea, dyspnea, and ischemic chest pain) or anginal equivalent. The protocol properly identified patients with impaired pulmonary function. There was no difference in the frequency of adverse marked events among groups A, B, or C (1 % vs 4% vs 2%, p = 0.25). Patients in group A had more minor side effects than those in group B (53% vs 35%, p = 0.004). Specifically, patients in group A were more likely to wheeze (39% vs 1 %, p = <0.001), but wheezing in group A was self-limited or responded to treatment as described in the protocol. The prevalence of positive thallium-201 scans in group A (44%) compared with group C (49%) was not different (p = 0.15). CONCLUSIONS: A nurse-administered risk assessment and pretreatment protocol (1) properly identified patients with impaired pulmonary function, (2) permitted completion of intravenous dipyridamole testing in patients at risk for bronchospasm without an increased incidence of marked adverse events, and (3) did not appear to influence the interpretation of the thallium test.

Chromium(III) decreases the fidelity of human DNA polymerase beta.

Certain particulate compounds of hexavalent chromium are well-known occupational and environmental human carcinogens. Hexavalent chromium primarily enters the cells and undergoes metabolic reduction; however, the ultimate trivalent oxidation state of chromium, Cr(III), predominates within the cell. DNA-bound Cr(III) has been previously shown to decrease the fidelity of replication in the M13 phage mutation assay. This study was done to understand how Cr(III), in the presence of physiological concentrations of magnesium, affects the kinetic parameters of steady-state DNA synthesis in vitro across site-specific O6-methylguanine (m6dG) residues by DNA polymerase beta (pol beta). Cr(III) binds to the short oligomer templates in a dose-dependent manner and stimulates the activity of pol beta. Cr(III) stimulates the mutagenic incorporation of dTTP opposite m6dG more than the nonmutagenic incorporation of dCTP, and thereby Cr(III) further decreases the fidelity of DNA synthesis across m6dG by pol beta. In contrast, Cr(III) does not affect the fidelity of DNA synthesis across the normal template base, dG. Both the enhanced activity and the mutagenic lesion bypass in the presence of Cr(III) may be associated with Cr(III)-dependent stimulation of pol beta binding to DNA as reported here. This study shows some of the mechanisms by which mutagenic chromium affects DNA synthesis.

Strength of signal through BCR determines the fate of cycling B cells by regulating the expression of the Bcl-2 family of survival proteins.

Cycling, splenic B cells were recultured with: (1) no stimulant to reflect poorly competitive clones; (2) soluble, whole anti-mu to reflect clones that bind soluble immune complexes; (3) soluble F(ab')2 anti-mu to reflect clones that bind soluble antigen; and (4) immobilized anti-mu to reflect clones that bind antigen presented by FDC. All four groups displayed similar levels of the death proteins Bax and Bcl-xS. In contrast, cycling B cells restimulated with either soluble F(ab')2 or immobilized anti-mu expressed heightened levels of the survival protein Bcl-xL, and only cells restimulated with immobilized anti-mu expressed the survival protein Bcl-2. Cycling B cells restimulated with either soluble F(ab')2 or immobilized anti-mu displayed a selective survival advantage over cycling B cells receiving no stimulus or soluble, whole anti-mu by both enhancing their responsiveness to CD40 ligand, a Th-cell-derived signal, and increasing the period that the cycling B cells remained responsive to this Th-cell-derived signal. The Th-cell-derived signal did not appreciably alter cycling B cell expression of Bcl-2 family members.

An in vitro approach for the characterization of the cycling B cell response.

Because isolation of sufficient numbers of cycling, germinal center B cells from mice for biochemical characterization of BCR-derived signals can be problematic, we have designed an experimental approach for generating large numbers of cycling B cells for further study. In the experiments reported here, small, resting B cells were polyclonally stimulated with lipopolysaccharide (LPS), and cycling B cells isolated as two bands on three-step Percoll gradients. Cycling B cells isolated at Days 2, 4, or 6 of preactivation showed an increased expression of Fas receptor and peanut agglutinin binding, with a concomitant decrease in sIgD positivity. These cells phenotypically resembled extrafollicular or early germinal center B cells. These cycling B cells were used to study the functional consequences of differential signaling through the BCR. Strong cross-linking of BCR, by restimulation of cycling normal B cells with either immobilized or soluble F(ab')2 anti-mu and cycling hen egg lysozyme (HEL) transgenic B cells with either soluble or immobilized HEL, extended cellular proliferation by 2-3 d. In contrast, cycling B cells either restimulated with soluble, whole anti-mu (to mimic binding of soluble immune complexes) or cultured in the absence of restimulation (to mimic cycling B cells not competitive for antigen) resulted in the rapid exit of the cells from cycle. This system will enable the molecular and biochemical characterization of signal delivery to cycling B cells.