An α-chain modification rivals the effect of fetal hemoglobin in retarding the rate of sickle cell fiber formation.

Adults with sickle cell disease bear a mutation in the β-globin gene, leading to the expression of sickle hemoglobin (HbS; αβ). Adults also possess the gene for γ-globin, which is a component of fetal hemoglobin (HbF, αγ); however, γ-chain expression normally ceases after birth. As HbF does not form the fibers that cause the disease, pharmacological and gene-modifying interventions have attempted to either reactivate expression of the γ chain or introduce a gene encoding a modified β chain having γ-like character.

Entropy of Charge Inversion in DNA including One-Loop Fluctuations.

The entropy and charge distributions have been calculated for a simple model of polyelectrolytes attached to the surface of DNA using a field-theoretic method that includes fluctuations to the lowest one-loop order beyond mean-field theory. Experiments have revealed correlation-driven behavior of DNA in charged solutions, including charge inversion and condensation. In our model, the condensed polyelectrolytes are taken to be doubly charged dimers of length comparable to the distance between sites along the phosphate chains.

The Sickle-Cell Fiber Revisited.

Sickle cell disease is the consequence of a single point mutation on the surface of the β chains of the hemoglobin molecule leading to the formation of rigid polymers that disrupt circulation. It has long been established that the polymers are comprised of seven pairs of double strands that are twisted replicas of the double strands found in crystals. Here, we review several newer developments that elaborate on that simple model and provide deeper insights into the process.

Factors in Early Adolescence Associated With a Mole-Prone Phenotype in Late Adolescence.

Importance: Nevi are important phenotypic risk factors for melanoma in adults. Few studies have examined the constitutional and behavioral factors associated with a mole-prone phenotype in adolescents.

Objective: To identify host, behavioral, and dermoscopic factors in early adolescence (age, 14 years) that are associated with a mole-prone phenotype in late adolescence (age, 17 years).

Dermatoscopic imaging of skin lesions by high school students: a cross-sectional pilot study.

Background: The ability of novices to perform imaging of skin lesions is not well studied.

Objectives: To determine the ability of 12th grade high school students without formal training to take clinical and dermatoscopic images of skin lesions on patient-actors.

Patients/methods: Nineteen participants were divided into 11 gender-specific groups of 1-2 students.

Tanning and beauty: Mother and teenage daughters in discussion.

Tanning increases dramatically through the teenage years, but the family context of this health risk behavior is relatively unstudied. We conducted videotaped conversations between teenage girls (10th and 11th grade) and their mothers. We developed a coding system for discussion content and highlight findings including inadequate knowledge concerning the harms of tanning and positive views of outdoor tanning over indoor tanning, yet agreement that all tans are attractive.

Clinical and dermoscopic stability and volatility of melanocytic nevi in a population-based cohort of children in Framingham school system.

Nevi are important risk markers of melanoma. The study aim was to describe changes in nevi of children using longitudinal data from a population-based cohort. Overview back photography and dermoscopic imaging of up to 4 index back nevi was performed at age 11 years (baseline) and repeated at age 14 years (follow-up).

The CHEER study to reduce BMI in Elementary School students: a school-based, parent-directed study in Framingham, Massachusetts.

Childhood obesity may be lessened by parent-focused interventions. A pilot parent-directed trial with 46 parents of overweight and obese elementary school students was conducted at two ethnically diverse public schools in Framingham, Massachusetts. Parents were randomly assigned to either the Materials Group, which received mailed educational materials, or the Materials plus Personal Encounters Group, which received educational materials through interactions with community health workers (CHWs).

Study of Nevi in Children (SONIC): baseline findings and predictors of nevus count.

The authors report baseline findings and predictors of nevus count (log total nevi) at the completion of year 1 (2004) of the first known population-based, prospective study of nevi in a US cohort of children. Overall, 64% (n = 443/691) of grade 5 students and their parents in Framingham, Massachusetts, completed surveys and underwent digital photography. Total nevus count was associated with skin and hair color and tendency to burn, as measured by a sun sensitivity index.

Study of health outcomes in school children: key challenges and lessons learned from the Framingham Schools' Natural History of Nevi Study.

Background: We describe the planning, recruitment, key challenges, and lessons learned in the development of a study of the evolution of nevi (moles) among children in a school setting.

Methods: This population-based study of digital photography and dermoscopy of the child's back (overview, close-up, and dermoscopic images) and genetic specimens took place among fifth graders in the Framingham, Massachusetts School System. Schoolchildren and their parents completed baseline surveys on sun protection practices, sunburns, and past ultraviolet exposures, including summer and vacation experiences.

Lattice-gas model of DNA charge inversion by a positively charged polyelectrolyte.

The model of DNA charge inversion by Nguyen and Shklovskii [T. T. Nguyen and B.