Transient receptor potential melastatin 4 channel is required for rat dental pulp stem cell proliferation and survival.

OBJECTIVES: Investigate the role of the transient receptor potential melastatin 4 (TRPM4) channel in rat dental pulp stem cell (DPSC) proliferation and survival. MATERIALS AND METHODS: Immunofluorescence and FACS analysis were used to detect the stem cell marker CD90. Alizarin Red S and Oil Red O staining were used to identify osteoblast and adipocyte differentiation, respectively. To characterize TRPM4, patch-clamp recordings were obtained from single cells in the whole-cell configuration mode. The significance of TRPM4 for proliferation and survival was examined with 9-phenanthrol, a TRPM4 inhibitor during a 96-hour period of culture. Real-time Ca2+ imaging analysis with Fura-2AM was used to investigate the impact of TRPM4 on intracellular Ca2+ signals. RESULTS: DPSCs were CD90-positive and differentiated into osteoblasts. Patch-clamp recordings revealed currents typical of TRPM4 that were Ca2+ -activated, voltage-dependent and Na+ -conducting. Inhibition of TRPM4 resulted in a significant reduction in the cell population after a 96-hr period of culture and transformed the biphasic pattern of intracellular Ca2+ signalling into sustained oscillations. CONCLUSIONS: Rat DPSCs have stem cell characteristics and functional TRPM4 channels that are required for proliferation and survival. These data suggest that the shape and frequency of intracellular Ca2+ signals may mediate stem cell proliferation and survival.

A millisecond pulsar in a stellar triple system.

Gravitationally bound three-body systems have been studied for hundreds of years and are common in our Galaxy. They show complex orbital interactions, which can constrain the compositions, masses and interior structures of the bodies and test theories of gravity, if sufficiently precise measurements are available. A triple system containing a radio pulsar could provide such measurements, but the only previously known such system, PSR B1620-26 (refs 7, 8; with a millisecond pulsar, a white dwarf, and a planetary-mass object in an orbit of several decades), shows only weak interactions. Here we report precision timing and multiwavelength observations of PSR J0337+1715, a millisecond pulsar in a hierarchical triple system with two other stars. Strong gravitational interactions are apparent and provide the masses of the pulsar M[Symbol: see text](1.4378(13), where M[Symbol: see text]is the solar mass and the parentheses contain the uncertainty in the final decimal places) and the two white dwarf companions (0.19751(15)M[Symbol: see text] and 0.4101(3))M[Symbol: see text], as well as the inclinations of the orbits (both about 39.2°). The unexpectedly coplanar and nearly circular orbits indicate a complex and exotic evolutionary past that differs from those of known stellar systems. The gravitational field of the outer white dwarf strongly accelerates the inner binary containing the neutron star, and the system will thus provide an ideal laboratory in which to test the strong equivalence principle of general relativity.

Pulsar discovery by global volunteer computing.

Einstein@Home aggregates the computer power of hundreds of thousands of volunteers from 192 countries to mine large data sets. It has now found a 40.8-hertz isolated pulsar in radio survey data from the Arecibo Observatory taken in February 2007. Additional timing observations indicate that this pulsar is likely a disrupted recycled pulsar. PSR J2007+2722's pulse profile is remarkably wide with emission over almost the entire spin period; the pulsar likely has closely aligned magnetic and spin axes. The massive computing power provided by volunteers should enable many more such discoveries.

Angiotensin-(1-7) serves as an aquaretic by increasing water intake and diuresis in association with downregulation of aquaporin-1 during pregnancy in rats.

We previously demonstrated that kidney and urine levels of angiotensin-(1-7) [ANG-(1-7)] were increased in pregnancy. To explore the role of ANG-(1-7) on fluid and electrolyte homeostasis during pregnancy, we evaluated the effect of the ANG-(1-7) antagonist D-alanine-[ANG-(1-7)] (A-779) on kidney function. Virgin and pregnant rats received infusion of vehicle or A-779 (48 microg.kg(-1).h(-1)) for 8 days by osmotic minipumps. Metabolic studies were done on treatment day 7-8. Virgin and pregnant rats at day 15 and 19 were killed, and blood and kidneys were collected. Kidneys were prepared for Western blot analysis for aquaporin-1 (AQP1) and aquaporin-2. In virgin female rats, A-779 increased urine volume and decreased urinary osmolality and AQP1 with no change in water intake. In 19-day pregnant rats, A-779 significantly decreased water intake and urine volume and increased urinary osmolality and kidney AQP1 expression. Only in late gestation did A-779 treatment decrease the difference between intake and output (balance). A-779 treatment increased plasma vasopressin in late gestation but did not change vasopressin in virgins. In virgin and pregnant animals, A-779 administration had no effect on blood pressure, plasma volume, blood volume, or urinary electrolytes. These results suggest that ANG-(1-7) produces antidiuresis associated with upregulation of AQP1 in virgin rats, whereas ANG-(1-7) produces diuresis in late gestation with downregulation of AQP1. ANG-(1-7) contributes to the enhanced water intake during pregnancy, allowing maintenance of the normal volume-expanded state despite diuresis produced in part by decreased AVP and AQP1.

Attachment for infants in foster care: the role of caregiver state of mind.

The concordance between foster mothers' attachment state of mind and foster infants' attachment quality was examined for 50 foster mother-infant dyads. Babies had been placed into the care of their foster mothers between birth and 20 months of age. Attachment quality was assessed between 12 and 24 months of age, at least 3 months after the infants' placement into foster care. The two-way correspondence between maternal state of mind and infant attachment quality was 72%, kappa = .43, similar to the level seen among biologically intact mother-infant dyads. Contrary to expectations, age at placement was not related to attachment quality. Rather, concordance between maternal state of mind and infant attachment was seen for relatively late-placed babies, as well as early placed babies. These findings have two major implications. First, following a disruption in care during the first year and a half of life, babies appear capable of organizing their behavior around the availability of new caregivers. Second, these data argue for a nongenetic mechanism for the intergenerational transmission of attachment.

The development of attachment in new relationships: single subject analyses for 10 foster infants.

This paper presents single-subject analyses of newly developing attachment relationships in 10 foster infant-caregiver dyads. Using a diary methodology, at least 2 months of daily data were provided by foster parents on infants' attachment behaviors. Foster infant attachment was also assessed using the Strange Situation. Foster mother state of mind regarding attachment was measured using the Adult Attachment Interview. For eight infants, diary data revealed predominant patterns of attachment behavior emerging within 2 months of placement. In most cases, diary data predicted Strange Situation classifications. Both Strange Situation and diary data indicated that the three children placed in foster care before 12 months of age with foster parents having primary or secondary autonomous states of mind were classified as having secure attachments. The five children placed after 12 months of age showed predominantly insecure attachment behavior in the diary and were classified as insecure in the Strange Situation. Contingency analyses of behavioral sequences reported in the diary revealed that foster parents tended to complement their foster childrens' attachment behaviors.

Cognitive level and health decision-making in children: A preliminary study.

The study examines children's stage of cognitive development in relation to their patterns of health decision-making, including their cognitive capabilities in integrating the sequential stages of the decision-making process. A sample of 81 male (N=33) and female (N=48) students were drawn from two urban public schools in West Tennessee. All participants in the study were of African-American descent. The Centers for Disease Control Decision-Making Instrument was used to assess students' decision-making as well as their understanding of the decision-making process. The children's cognitive level was determined by their performance on three Piagetian conservation tasks. Findings revealed that both the preoperational and concrete operational children performed significantly below the formal operational children in terms of total correct responses to the decision-making scenarios. Error type analyses indicated that the preoperational children made more errors involving "skipped step" than did either the concrete or formal operational children. There were no significant differences between children's level of cognitive development and any other error type. Implications for health promotion and disease prevention programs among prevention practitioners who work regularly with children are discussed.