The dissociation and assembly of quadruplex DNA structures (and a few quadruplex RNAs) have been characterized at several levels of rigor, ranging from gross descriptions of factors that govern each process, to semiquantitative comparisons of the relative abilities of these factors to induce stabilization or destabilization, to quantitative studies of binding energies (thermodynamics), transformational rates (kinetics), and analysis of their transition‐state energies and mechanisms. This survey classifies these factors, describes the trends and focuses on their interdependencies. Quadruplex assembly is induced most efficiently by added K+ and elevating the strand concentration; however, Na+, NH4+, Sr2+, and Pb2+ are also very effective stabilizers. Quadruplex dissociation is typically accomplished by thermal denaturation, “melting”; however, when the quadruplex and monovalent cation concentrations are low enough, or the temperature is sufficiently high, several divalent cations, e.g., Ca2+, Co2+, Mn2+, Zn2+, Ni2+ and Mg2+ can induce dissociation. Stabilization also depends on the type of structure adopted by the strand (or strands) in question. Variants include intramolecular, two‐ and four‐stranded quadruplexes. Other important variables include strand sequence, the size of intervening loops and pH, especially when cytosines are present, base methylation, and the replacement of backbone phosphates with phosphorothioates. Competitive equilibria can also modulate the formation of quadruplex DNAs. For example, reactions leading to Watson–Crick (WC) duplex and hairpin DNAs, triplex DNAs, and even other types of quadruplexes can compete with quadruplex association reactions for strands. Others include nonprotein catalysts, small molecules such as aromatic dyes, metalloporphyrins, and carbohydrates (osmolytes). Other nucleic acid strands have been found to drive quadruplex formation. To help reinforce the implications of each piece of information, each functional conclusion drawn from each cited piece of thermodynamic or kinetic data has been summarized briefly in a standardized table entry. © 2001 John Wiley & Sons, Inc. Biopolymers (Nucleic Acid Sci) 56: 147–194, 2001

eczema refractory to topical corticosteroids: results of a randomized, double-blind, placebo-controlled, multicentre trial. Br J Dermatol 2008; 158:808-17. 7 Molin S, Ruzicka T. Possible benefit of oral alitretinoin in T-lymphoproliferative diseases: a report of two patients with palmoplantar hyperkeratotic-rhagadiform skin changes and mycosis fungoides or Sézary syndrome. Br

Background: Strong evidence supports positive correlation of physical activity with health benefits. Current recommendations by the American Heart Association are a minimum 30 minutes of moderate physical activity 5 days per week. This goal has been equilibrated with 10,000 steps per day. Hypothesis: Work-related physical activity of cardiovascular (CV) specialists does not meet the currently recommended daily physical activity. Methods: Eight cardiothoracic (CT) surgeons, 7 general cardiologists, 5 procedural cardiologists, and 8 cardiac anesthesiologists (N = 28) participated in the study. Demographic information on each participant was recorded including age, resting heart rate, body mass index, and medical and social history. Subjects were asked to wear a spring-levered pedometer on their hip for 2 weeks while at work and to record the total number of steps as well as number of hours worked each day. Results: The average daily steps walked during work were 6540, 6039, 5910, and 5553 for general cardiologists, CT surgeons, procedural cardiologists, and cardiac anesthesiologists, respectively. There were no statistically significant differences in the average number of steps taken per day among the groups. CT surgeons worked 12.4 hours per day compared to 9.3 hours by the cardiac anesthesiologists (P = 0.03). Conclusions: In this small, single-center study, work-related physical activity of CV specialists did not meet the recommended guidelines. Obtaining the recommended activity level might be a challenge, given their busy work schedule. Therefore, CV specialists must engage in additional, out-of-hours exercise to achieve the recommended daily exercise.

Multiple clustered dermatofibromas describes a confluence of dermatofibromas in one anatomic location. We describe a 32-yearold man who presented for evaluation owing to skin papules and plaques and concerns about malignancy. Repeat histopathological evaluation found no evidence for dermatofibrosarcoma protuberans. Our case presents this relatively rare condition and discusses observation along with potential treatment options. Case synopsisA 32-year-old man initially presented in 2009 with a reticulated red-brown plaque on his left thigh that had been present and stable for approximately 15-years. However, 4-months prior to presentation it progressively expanded. The patient denied a history of trauma; other than occasional pruritus, the lesion was asymptomatic. A punch biopsy was performed, but the patient was lost to follow-up. The patient recently returned to clinic for re-evaluation. On physical examination, there was an ill-defined 10 x 20 cm region on the left anterior thigh composed of multiple red-brown plaques that varied in size and shape with intervening areas of normal appearing skin (Figure 1). The epidermis overlying some of the plaques had a wrinkled appearance and some plaques were focally depressed (Figure 2). Reduction of terminal hairs was also noted in this region. An incisional biopsy was performed (Figure 3 and 4).