Recent genome-wide analyses have elucidated the extent of alternative splicing (AS) in mammals, often focusing on comparisons of splice isoforms between differentiated tissues. However, regulated splicing changes are likely to be important in biological transitions such as cellular differentiation, or response to environmental stimuli. To assess the extent and significance of AS in myogenesis, we used splicing-sensitive microarray analysis of differentiating C2C12 myoblasts. We identified 95 AS events that undergo robust splicing transitions during C2C12 differentiation. More than half of the splicing transitions are conserved during differentiation of avian myoblasts, suggesting the products and timing of transitions are functionally significant. The majority of splicing transitions during C2C12 differentiation fall into four temporal patterns and were dependent on the myogenic program, suggesting that they are integral components of myogenic differentiation. Computational analyses revealed enrichment of many sequence motifs within the upstream and downstream intronic regions near the alternatively spliced regions corresponding to binding sites of splicing regulators. Western analyses demonstrated that several splicing regulators undergo dynamic changes in nuclear abundance during differentiation. These findings show that within a developmental context, AS is a highly regulated and conserved process, suggesting a major role for AS regulation in myogenic differentiation.

IMPORTANCE Dermatofibrosarcoma protuberans (DFSP) may have a deceptively benign clinical appearance, including a nonprotuberant presentation. Patients with DFSP often perceive misdiagnoses and delays in receiving a diagnosis. Use of existing, patient-designed Facebook patient support groups (FBSGs) to recruit large numbers of patients with rare diseases may be an effective novel research method. OBJECTIVES To collaborate with patients with rare disease through social media and answer questions important to both patients and the medical field, including sources of diagnostic delay, risk of recurrence, and flat presentation of DFSP.

Aspergillus species are capable of causing both invasive disease and chronic infections in immunocompromised patients or those with preexisting lung conditions. Aspergillus fumigatus is the most commonly cultured species, and there is increasing concern regarding resistance to the azoles, which are the mainstays of antifungal therapy against aspergillosis. We evaluated the species distribution and susceptibility profiles of isolates within Aspergillus section Fumigati in the United States over a 52-month period.

The global incidence of mucormycosis has increased in recent years owing to higher numbers of individuals at risk for these infections. The diagnosis and treatment of this aggressive fungal infection are of clinical concern due to differences in species distribution in different geographic areas and susceptibility profiles between different species that are capable of causing highly aggressive infections. The purpose of this study was to evaluate the epidemiology and susceptibility profiles of Mucorales isolates in the U.S. over a 52-month period. Species identification was performed by combined phenotypic characteristics and DNA sequence analysis, and antifungal susceptibility testing was performed by CLSI M38 broth microdilution for amphotericin B, isavuconazole, itraconazole, and posaconazole. During this time-frame, 854 isolates were included, representing 11 different genera and over 26 species, of which Rhizopus (58.6%) was the predominant genus followed by Mucor (19.6%). The majority of isolates were cultured from the upper and lower respiratory tracts (55%). Amphotericin B demonstrated the most potent in vitro activity, with GM MICs of ≤0.25 μg/mL against all genera with the exception of Cunninghamella species (GM MIC 1.30 μg/mL). In head-to-head comparisons the most active azole was posaconazole followed by isavuconazole. Differences in azole and amphotericin B susceptibility patterns were observed between the genera with the greatest variability observed with isavuconazole. Awareness of the epidemiology of Mucorales isolates and differences in antifungal susceptibility patterns in the U.S. may aide clinicians in choosing antifungal treatment regimens. Further studies are warranted to correlate these findings with clinical outcomes.