Premature thelarche in infants and toddlers: prevalence, natural history and environmental determinants

Study Objective

The aim of this study was to measure the prevalence of premature thelarche in infant and toddler girls and to determine if environmental sources of estrogen were associated with early breast development.

Design

Observational with mixed methods: Retrospective chart review, cross-sectional component involving an interview survey, along with longitudinal follow-up of girls with thelarche up to six months.

Setting

A general pediatric clinic within a teaching hospital located in a large Midwestern city.

Participants

Girls, between the ages of 12 and 48 months, and their mothers, presenting for well-child care.

Interventions

None.

Main Outcome Measures

Prevalence of premature thelarche; association of premature thelarche with selected environmental exposures.

Results

Among the 318 subjects, the overall prevalence of premature thelarche was measured at 4.7% (n = 15). The prevalence by race/ethnicity was 4.2% among White Non-Hispanics, 4.6% among Blacks and 6.5% among White Hispanics. The peak prevalence occurred between 12–17 months of age. All thelarche cases were Tanner stage 2. No statistically significant relationship was found between premature thelarche and environmental exposures. Upon follow-up, 44% of the cases of premature thelarche had persistent breast development.

Conclusions

Our study demonstrated a higher prevalence of premature thelarche than has been previously reported. This study lacked power because of the small number of premature thelarche cases, the ubiquitous presence of environmental exposure as well as the potentially small effect of each environmental factor. Future studies need to employ a very large sample in order to accurately analyze the relationship between environmental toxicants and premature thelarche.     

Family stories: narrative genetics and conceptions of heritability in pregnant women

As our understanding of genetics has grown, and its importance has increased in clinical care, pregnancy and the fetus are often seen through a genetic lens. Clinicians who care for pregnant women are charged with explaining genetic risk and overseeing prenatal screening. For the clinician, genetics represents clearly defined application of a particular kind of scientific knowledge. Further, heritability in clinical terms is understood as purely genetic. Pregnant women themselves, however, may not give these genetic explanations the same primacy or meaning. In order to better understand the way pregnant women actually understand and explain heritability, we completed in-depth interviews with 26 pregnant women, listening as they gave weight and substance to the various factors they describe as influencing the personhood of their unborn children. Two-thirds of our respondents were Hispanic or African American. Most were recruited through programs that serve low-income women. The interviews were coded and analyzed by using categories that emerged directly from the narratives captured in the interviews and that revealed the broad, cross-cutting, overlapping parameters of women's deeply-held beliefs about heritability. These stories represent narratives of heritability that are profoundly familial and cultural. They incorporate belief in the authoritative knowledge of medicine-including any genetic information-into a complex and usually multicultural context, woven together by ancestry, household, and community.     

A new framework for quality partnerships in Children's Hospitals

Children's hospitals and their affiliated departments of pediatrics often pursue separate programs in quality and safety; by integrating these programs, they can accelerate progress. Hospital executives and pediatric department chairs from 14 children's hospitals have been exploring practical approaches for integrating quality programs. Three components provide focus: (1) alignment of quality priorities and resources across the organizations; (2) education and training for physicians in the science of improvement; and (3) professional development and career progression for physicians in recognition of quality-improvement activities. Process and resource requirements are identified for each component, and specific, actionable steps are identified. The action steps are arrayed on a continuum from basic to advanced integration. The resulting matrix serves as an "integration framework," useful to a hospital and its pediatric academic department at any stage of integration for assessing its current state, plotting a path toward further integration, tracking its progress, and identifying potential collaborators and models of advanced integration. The framework contributes to health care's quality-improvement movement in multiple ways: it addresses a basic impediment to quality and safety improvement; it is an implementable model for integrating quality programs; it offers career-advancement potential for physicians interested in quality; it helps optimize investments in quality and safety; and it can be applied both within a single children's hospital and across multiple children's hospitals. Widespread adoption of the integration framework could have a transformative effect on the children's hospital sector, not the least of which is improved quality and safety on a large scale.     

Increased culture recovery of Zygomycetes under physiologic temperature conditions

Poor recovery of Zygomycetes hyphae from tissue specimens may result from failure of current culture methods to mimic physiologic conditions found in hyphae-laden infected tissue. We describe the use of an in vitro model simulating Zygomycetes growth under necrotic or hypoxic tissue conditions. We preconditioned hyphae of clinical Zygomycetes isolates in flasks under anaerobic conditions using Ana-Packs (Becton Dickinson Microbiology Systems, Sparks, MD) at 37 degrees C for 48 hours, thus simulating in vivo growth in an infracted hypoxic lesion, and compared the recovery of paired inocula at 37 degrees C and 25 degrees C. Incubation of stock culture isolates at 37 degrees C resulted in significantly better culture recovery (about 10-fold) when compared with incubation at 25 degrees C (P < .0001). In addition, we similarly evaluated 25, 291 consecutive clinical specimens. Among 41 specimens, the yield of Zygomycetes cultures incubated at 37 degrees C (23/41 [56%]) was significantly higher than that incubated at 25 degrees C (9/41 [22%]; P = .0001). Overall, we found that culture recovery was significantly (254%) enhanced at 37 degrees C.     

The International society for developmental psychobiology 39th annual meeting symposium: Alcohol and development: beyond fetal alcohol syndrome

As has been repeatedly demonstrated, alcohol can exert deleterious morphological and physiological effects during early stages in development. The present review examines nonteratological links existing between alcohol and ontogeny. Human and animal studies are taken into consideration for the analysis of fetal, neonatal, infantile, adolescent, and adult responsiveness to the drug. Sensitivity to alcohol's chemosensory and postabsorptive properties, as well as learning and memory processes mediated by such properties, are examined from this developmental perspective. The studies under discussion indicate that, within each stage in development, we can trace alcohol-related experiences capable of determining or modulating alcohol seeking and intake patterns.     

Biophysical characterization of vaccinia virus thymidine kinase substrate utilization

To provide information for the development of new antiviral compounds that inhibit orthopoxviruses, further characterization of the kinetics and thermodynamics that underlie substrate utilization reactions of vaccinia virus thymidine kinase (VVTK) has been undertaken. The kinetics of 2'deoxythymidine phosphorylation by VVTK and the thermodynamics of complex formation between VVTK and the substrate 2' deoxythymidine were determined using spectroscopic and calorimetric techniques. These studies demonstrated that kinetic parameters for 2' deoxythymidine phosphorylation by VVTK were 25 microM and 0.2s(-1) for K(m) and k(cat), respectively. The enthalpy change, Delta H, for the enzyme catalyzed reaction is -18.1 kcal/mol. Thermodynamic studies for the formation of the enzyme substrate complex demonstrated a binding affinity (K(a)) of 4 x 10(4)M(-1), an enthalpy change for binding (Delta H) of -17.4 kcal/mol, and a reaction stoichiometry of two molecules of substrate binding to each enzyme tetramer. Kinetic and thermodynamic data were in agreement (K(a) approximately 1/K(m)) and showed similarities to literature values reported for herpes simplex virus thymidine kinase (HSV-TK) and human thymidine kinase 1 (hTK1) with respect to k(cat) but not with respect to K(m). The K(m) value found for VVTK in this study is nearly two orders of magnitude larger than the values reported for the hTK1 and the HSV TK enzymes.