Recommendations for High-resolution Peripheral Quantitative Computed Tomography Assessment of Bone Density, Microarchitecture, and Strength in Pediatric Populations.

PURPOSE OF REVIEW: The purpose of this review is to summarize current approaches and provide recommendations for imaging bone in pediatric populations using high-resolution peripheral quantitative computed tomography (HR-pQCT). RECENT FINDINGS: Imaging the growing skeleton is challenging and HR-pQCT protocols are not standardized across centers. Adopting a single-imaging protocol for all studies is unrealistic; thus, we present three established protocols for HR-pQCT imaging in children and adolescents and share advantages and disadvantages of each. Limiting protocol variation will enhance the uniformity of results and increase our ability to compare study results between different research groups. We outline special cases along with tips and tricks for acquiring and processing scans to minimize motion artifacts and account for growing bone. The recommendations in this review are intended to help researchers perform HR-pQCT imaging in pediatric populations and extend our collective knowledge of bone structure, architecture, and strength during the growing years.

Longitudinal bone microarchitectural changes are best detected using image registration.

Longitudinal studies of bone using high-resolution medical imaging may result in non-physiological measurements of longitudinal changes. In this study, we determined that three-dimensional image processing techniques best capture realistic longitudinal changes in bone density and should therefore be used with high-resolution imaging when studying bone changes over time. INTRODUCTION: The purpose of this study was to determine which longitudinal analysis technique (no registration (NR), slice-match (SM) registration, or three-dimensional registration (3DR)) produced the most realistic longitudinal changes in a 3-year study of bone density and structure using high-resolution peripheral quantitative computed tomography (HR-pQCT). METHODS: We assessed HR-pQCT scans of the distal radius and tibia for men and women (N = 40) aged 55-70 years at baseline and 6, 12, 24, and 36 months. To evaluate which longitudinal analysis technique (NR, SM, or 3DR) best captured physiologically reasonable 3-year changes, we calculated the standard deviation of the absolute rate of change in each bone parameter. The data were compared between longitudinal analysis techniques using repeated measures ANOVA and post hoc analysis. RESULTS: As expected, both SM and 3DR better captured physiological longitudinal changes than NR. At the tibia, there were no differences between SM and 3DR; however, at the radius where precision was lower, 3DR produced better results for total bone mineral density. CONCLUSIONS: At least SM or 3DR should be implemented in longitudinal studies using HR-pQCT. 3DR is preferable, particularly at the radius, to ensure that physiological changes in bone density are observed.

Reference data for jumping mechanography in Canadian children, adolescents and young adults.

OBJECTIVES: To provide age- and sex-specific reference data for mechanography-derived parameters of muscle function in Canadian children and youth using the single two-legged jump (S2LJ) with hands-on-waist. METHODS: Our sample included 2017 observations from 715 participants (9-21 years; 338 girls). Participants performed three S2LJ with hands-on-waist on a force platform (Leonardo Mechanograph, Novotec). Outcomes were maximum peak power (Pmax), Pmax/mass, peak force/body weight (Fmax/BW), force efficiency, maximum jump height (Hmax), and velocity (Vmax). We used the LMS method to construct age- and sex-specific percentile curves and mixed effects models to examine sex and ethnic differences. RESULTS: With the exception of Efficiency, mechanography outcomes were greater in girls (4-40%, p<0.05) than boys at age 9. Boys' advantage in mechanography parameters emerged in adolescence (age 11-13 years; 3-65%, p<0.05) and persisted into young adulthood, except for Fmax/BW which was not greater in boys until age 17 (4-10%, p<0.05). Mechanography outcomes were 3-9% (p<0.05) greater in Asian compared with white participants. CONCLUSIONS: We provide the first reference data for the S2LJ using the hands-on-waist protocol in children, youth and young adults. These data support previous findings using freely moving arms and can be used when evaluating muscle function in pediatric studies.

Associations of sedentary time patterns and TV viewing time with inflammatory and endothelial function biomarkers in children.

OBJECTIVE: Investigate associations of TV viewing time and accelerometry-derived sedentary time with inflammatory and endothelial function biomarkers in children. METHODS: Cross-sectional analysis of 164 7-10-year-old children. TV viewing time was assessed by parental proxy report and total and patterns of sedentary time accumulation (e.g. prolonged bouts) were assessed by accelerometry. C-reactive protein (CRP), homeostasis model assessment of insulin resistance, interleukin-2, -6, -8, -10, tumour necrosis factor alpha, adiponectin, resistin, brain-derived neurotrophic factor, soluble intercellular and vascular adhesion molecule 1, plasminogen activator inhibitor 1 and soluble E-selectin were assessed. Generalised linear models assessed the associations of TV viewing and sedentary time with biomarkers, adjusting for sex, waist circumference, moderate- to vigorous-intensity physical activity and diet density. RESULTS: Each additional h week(-1) of TV viewing was associated with 4.4% (95% CI: 2.1, 6.7) greater CRP and 0.6% (0.2, 1.0) greater sVCAM-1 in the fully adjusted model. The association between frequency and duration of 5-10 min bouts of sedentary time and CRP was positive after adjustment for sex and waist circumference but attenuated after adjustment for diet density. CONCLUSIONS: This study suggests that TV viewing was unfavourably associated with several markers of inflammation and endothelial dysfunction. The detrimental association between 5 and 10 min bouts of sedentary time and CRP approached significance, suggesting that further research with a stronger study design (longitudinal and/or experimental) is needed to better understand how the accumulation of sedentary time early in life may influence short and longer term health.

Impaired detection of variable duration embedded tones in ectopic NZB/BINJ mice.

Utilizing rodent models, prior research has demonstrated a significant association between focal neocortical malformations (i.e. induced microgyria, molecular layer ectopias), which are histologically similar to those observed in human dyslexic brains, and rate-specific auditory processing deficits as seen in language impaired populations. In the current study, we found that ectopic NZB/BINJ mice exhibit significant impairments in detecting a variable duration 5.6 kHz tone embedded in a 10.5 kHz continuous background, using both acoustic reflex modification and auditory event-related potentials (AERP). The current results add further support to the association between focal cortical malformations and impaired auditory processing, and the notion that these auditory effects may occur regardless of the cortical location of the anomaly.

A new method for evaluating antitussives in cats using an electrode-cannula.

An emplaced laryngo-tracheal electrode-cannula was employed to induce and to measure cough in cats anesthetized with either sodium pentobarbital or Dial--urethane. Carbetapentane citrate, codeine sulfate and dextromethorphan hydrobromide were tested for antitussive action by this method. Relative antitussive potency obtained in order of decreasing effectiveness was dextromethorphan hydrobromide, codeine sulfate and carbetapentane citrate.

Quality of care and black American patients.

Even with major advancements in medical knowledge and significant improvements in health sciences technology, evidence still exists that blacks do not enjoy as full a measure of health as do other racial and ethnic groups. To attempt a better understanding of this situation, literature was reviewed to consider relationships between being black and issues related to quality of health care. It was determined that these relationships have not been studied to any great extent, either in quantity or quality. When such studies have been undertaken, they have been limited to mostly qualitative designs, and appropriate controls for confounding variables have been minimal. The psychiatric literature reports most of the studies with very few studies found in the literature of other specialties. A conceptual model is presented regarding race-related research. It is argued that a first step might be to study whether the quality of care differs when the physician and the patient are members of different racial groups compared with when the physician and patient are members of the same racial group. In all race-related research, it is necessary to carefully consider specific variables that may confound results, eg, diagnostic errors, age, sex, socioeconomic status, level of education, geographic locale, and method of payment for health-care services.

Lake Erie College of Osteopathic Medicine's independent study pathway program: an alternative medical school curriculum design.

Lake Erie College of Osteopathic Medicine has developed an independent study pathway as an alternative to the traditional medical school curriculum design. Beginning with the 2001-2002 academic year, three equivalent and distinct curriculum pathways will be available to medical students at the Lake Erie College of Osteopathic Medicine: the lecture/discussion pathway, the problem-based learning pathway, and the independent study pathway (ISP). The ISP program will provide flexibility for students during their preclinical years. Using highly structured faculty-developed modules, students in the ISP program will be responsible for their own learning in a self-directed, independent manner, including when, where, what, and how to study. Examinations will be taken when students consider themselves ready. If examinations reveal deficiencies in student preparation, these deficiencies must be remedied before students continue their studies. Faculty will be available, as needed, to assist the students through difficult concepts and material.

Research process. Preparing a research proposal.

The preparation of a research proposal is often a necessary step in the research process. Research proposals are used to secure permission to undertake a study, to ensure protection of subjects, to secure needed resources, and to achieve a refined perspective of the proposed study. This third article of a series of six on the research process describes the steps involved in preparing a research proposal, demonstrating a parallel to the research planning process.

Research process. An overview.

It has been suggested that podiatric education, training, and practice too often are not well understood outside of the profession. If this is the case, a potential remedy is for more podiatric health professionals to publish work that has significance. Beginning with this article and continuing through a total of six articles, the research process is used as a paradigm for enhancing podiatric literature in the future.

Research process. Planning the research project.

This second article in a series of six on the research process provides a guide to planning a research project from start to finish. By description and illustration, 13 steps are outlined. Although the guide is comprehensive, advice is offered at strategic points regarding the value of consulting with a research specialist or a colleague experienced in research to gain assistance or insight into the planning process. Additionally, an admonition underlies the whole process: keep it simple and succinct.

Research process. Conducting the research project.

Conducting the research study should be a methodical process in which the details of the planning process are executed. This fourth article in a series of six on the research process presents guidelines with supporting recommendations to increase the likelihood that the study indeed will be conducted as planned. The guidelines emphasize the importance of 1) record-keeping systems, 2) detailed work schedules, 3) communications, and 4) monitoring progress.

Research process. Concluding the research project.

This fifth article in a series of six on the research process provides guidelines for concluding a research project. Attention is directed toward a need for the researcher to be sensitive to the persons who supported the project. The other significant aspect of concluding a research project involves activities associated with analyzing the data, preparing the results, and finalizing the findings.

Research process. Reporting results of the research.

The preparation of a manuscript to report a research project is the final stage of the research process. Recommendations are made in this article related to preparing to write, getting started, guarding against problems and frustrations by making early decisions, and developing each component of the manuscript. This article is the last in a series of six on the research process, in which the collective purpose has been to offer guidance regarding the spectrum of skills required to produce quality research reports.

Preventing substance abuse. An interview paradigm.

In summary, substance use and abuse is a major health problem in the United States affecting adolescents of both sexes and of every socioeconomic level. Family physicians have numerous opportunities to improve the health of future generations by using specific skills and expertise to prevent, identify, and intervene with adolescents' abuse of alcohol and other chemical substances. The first step is taking an effective alcohol and drug-use history.

Surgical practice and perceived training needs of selected Ohio family physicians.

This study was performed to determine, relative to Ohio, what percentage of family physicians are actively involved in providing surgical care, what types of surgical care are provided, and what variations exist in opinions and practices regarding surgery related to previous training and practice location. Data were collected from active members of the Ohio Academy of Family Physicians; usable returns were secured from 76 percent of the members. Several conclusions were made. Overwhelming percentages of family physicians in Ohio are actively involved in providing surgical care. A considerably greater percentage of family physicians are actively involved in performing minor surgery compared with major surgery, although they perform a wide range of minor and major surgical procedures at relatively high frequencies. Over the years, however, there has been a decrease in performance of major surgery on the part of family physicians in Ohio. Issues related to surgery in family practice are more positively influenced by being in a rural practice rather than an urban or suburban practice, having had more surgical training, and having had family practice residency training. Family physicians in Ohio definitely think that surgical training should be included in family practice training programs, and they think that the surgical training should be balanced between a curriculum standardized for all residents and one individualized to the anticipated future practices of the residents.

Dcdc2 knockout mice display exacerbated developmental disruptions following knockdown of doublecortin.

The dyslexia-associated gene DCDC2 is a member of the DCX family of genes known to play roles in neurogenesis, neuronal migration, and differentiation. Here we report the first phenotypic analysis of a Dcdc2 knockout mouse. Comparisons between Dcdc2 knockout mice and wild-type (wt) littermates revealed no significant differences in neuronal migration, neocortical lamination, neuronal cilliogenesis or dendritic differentiation. Considering previous studies showing genetic interactions and potential functional redundancy among members of the DCX family, we tested whether decreasing Dcx expression by RNAi would differentially impair neurodevelopment in Dcdc2 knockouts and wild-type mice. Consistent with this hypothesis, we found that deficits in neuronal migration, and dendritic growth caused by RNAi of Dcx were more severe in Dcdc2 knockouts than in wild-type mice with the same transfection. These results indicate that Dcdc2 is not required for neurogenesis, neuronal migration or differentiation in mice, but may have partial functional redundancy with Dcx.

Mutation of the dyslexia-associated gene Dcdc2 impairs LTM and visuo-spatial performance in mice.

Developmental reading disorder (RD) affects 5-10% of school aged children, with a heritability of approximately 60%. Genetic association studies have identified several candidate RD susceptibility genes, including DCDC2; however, a direct connection between the function of these genes and cognitive or learning impairments remains unclear. Variants in DCDC2, a member of the doublecortin family of genes, have been associated in humans with RD and ADHD and Dcdc2 may play a role in neuronal migration in rats. In this study, we examined the effect of Dcdc2 mutation on cognitive abilities in mice using a visual attention and visuo-spatial learning and memory task. We show that both heterozygous and homozygous mutations of Dcdc2 result in persistent visuo-spatial memory deficits, as well as visual discrimination and long-term memory deficits. These behavioral deficits occur in the absence of neuronal migration disruption in the mutant mice, and may be comorbid with an anxiety phenotype. These are the first results to suggest a direct relationship between induced mutation in Dcdc2 and changes in behavioral measures. Dcdc2 mutant mice should prove useful in future studies designed to further dissect the underlying neural mechanisms that are impaired following Dcdc2 mutation.