A dynamic in vitro developing testis model reflects structures and functions of testicular development in vivo.

To better define appropriate applications of our 3-dimensional testicular co-culture as a model for reproductive toxicology, we evaluated the ability of the model to capture structural and functional elements that can be targeted by reproductive toxicants. Testicular co-cultures were prepared from postnatal day 5 male rats and cultured with a Matrigel overlay. Following a 2-day acclimation period, we characterized functional pathway dynamics by evaluating morphology, protein expression, testosterone concentrations, and global gene expression at a range of timepoints from experimental days 0-21. Western blotting confirmed expression of Sertoli cell, Leydig cell, and spermatogonial cell-specific protein markers. Testosterone detected in cell culture media indicates active testosterone production. Quantitative pathway analysis identified Gene Ontology biological processes enriched among genes significantly changing over the course of 21 days. Processes enriched among genes significantly increasing through time include general developmental processes (morphogenesis, tissue remodeling, etc.), steroid regulation, Sertoli cell development, immune response, and stress and apoptosis. Processes enriched among genes significantly decreasing over time include several related to male reproductive development (seminiferous tubule development, male gonad development, Leydig cell differentiation, Sertoli cell differentiation), all of which appear to peak in expression between days 1 and 5 before decreasing at later timepoints. This analysis provides a temporal roadmap for specific biological process of interest for reproductive toxicology in the model and anchors the model to sensitive phases of in vivo development, helping to define the relevance of the model for in vivo processes.

An exomoon survey of 70 cool giant exoplanets and the new candidate Kepler-1708 b-i.

Exomoons represent a crucial missing puzzle piece in our efforts to understand extrasolar planetary systems. To address this deficiency, we here describe an exomoon survey of 70 cool, giant transiting exoplanet candidates found by Kepler. We identify only one exhibiting a moon-like signal that passes a battery of vetting tests: Kepler-1708 b. We show that Kepler-1708 b is a statistically validated Jupiter-sized planet orbiting a Sun-like quiescent star at 1.6 au. The signal of the exomoon candidate, Kepler-1708 b-i, is a 4.8σ effect and is persistent across different instrumental detrending methods, with a 1% false-positive probability via injection-recovery. Kepler-1708 b-i is ~2.6 Earth radii and is located in an approximately coplanar orbit at ~12 planetary radii from its ~1.6 au Jupiter-sized host. Future observations will be necessary to validate or reject the candidate.

Feasibility of rapid polymerase chain reaction for detection of methicillin-resistant Staphylococcus aureus colonization among emergency department patients with abscesses.

PURPOSE: In the era of community-associated methicillin-resistant Staphylococcus aureus (MRSA), clinicians face a difficult challenge when selecting antibiotics to treat abscesses. The lack of rapid diagnostics capable of identifying the causative organism often results in suboptimal antibiotic stewardship practices. Although not fully elucidated, the association between MRSA colonization and subsequent infection represents an opportunity to enhance antibiotic selectivity. Our primary objective was to examine the feasibility of utilizing a rapid polymerase chain reaction (PCR) system (Cepheid's GeneXpert(®)) to detect MRSA colonization prior to patient discharge in the emergency department (ED). METHODS: This feasibility study was conducted at a tertiary care, urban, academic ED. Patients presenting with a chief complaint related to a potential abscess during daytime hours over an 18-week period were screened for eligibility. Subjects were enrolled into either the PCR swab protocol group (two-thirds) or traditional care group (one-third). PCR swabs were obtained from known MRSA carriage sites (nasal, pharyngeal) and the superficial aspect of the wound. RESULTS: The two groups were similar in terms of demographics, abscess location, and MRSA history. The PCR results were available prior to patient discharge in 100% of cases. The turnaround times in minutes for the PCR swabs were as follows: nasal 73 ± 7, pharyngeal 82 ± 14, and superficial wound 79 ± 17. No significant difference in length of stay was observed between the two groups. The observed ideal antibiotic selection rates improved by 45% in the PCR group, but this trend was not significant (P = 0.08). CONCLUSION: When collected in triage, PCR swabs demonstrated turnaround times that were effective for use in the ED setting. Utilizing a rapid PCR MRSA colonization detection assay for ED patients with abscesses did not adversely impact the length of stay. Real-time determination of MRSA colonization may represent an opportunity to improve antibiotic selectivity in the treatment of abscesses.

The phase-dependent infrared brightness of the extrasolar planet upsilon Andromedae b.

The star upsilon Andromedae is orbited by three known planets, the innermost of which has an orbital period of 4.617 days and a mass at least 0.69 that of Jupiter. This planet is close enough to its host star that the radiation it absorbs overwhelms its internal heat losses. Here, we present the 24-micrometer light curve of this system, obtained with the Spitzer Space Telescope. It shows a variation in phase with the orbital motion of the innermost planet, demonstrating that such planets possess distinct hot substellar (day) and cold antistellar (night) faces.

Probing the faintest stars in a globular star cluster.

NGC 6397 is the second closest globular star cluster to the Sun. Using 5 days of time on the Hubble Space Telescope, we have constructed an ultradeep color-magnitude diagram for this cluster. We see a clear truncation in each of its two major stellar sequences. Faint red main-sequence stars run out well above our observational limit and near to the theoretical prediction for the lowest mass stars capable of stable hydrogen burning in their cores. We also see a truncation in the number counts of faint blue stars, namely white dwarfs. This reflects the limit to which the bulk of the white dwarfs can cool over the lifetime of the cluster. There is also a turn toward bluer colors in the least luminous of these objects. This was predicted for the very coolest white dwarfs with hydrogen-rich atmospheres as the formation of H(2) and the resultant collision-induced absorption cause their atmospheres to become largely opaque to infrared radiation.

A young white dwarf companion to pulsar B1620-26: evidence for early planet formation.

The pulsar B1620-26 has two companions, one of stellar mass and one of planetary mass. We detected the stellar companion with the use of Hubble Space Telescope observations. The color and magnitude of the stellar companion indicate that it is an undermassive white dwarf (0.34 +/- 0.04 solar mass) of age 480 x 10(6) +/- 140 x 10(6) years. This places a constraint on the recent history of this triple system and supports a scenario in which the current configuration arose through a dynamical exchange interaction in the cluster core. This implies that planets may be relatively common in low-metallicity globular clusters and that planet formation is more widespread and has happened earlier than previously believed.