Measure of Caregiver Attention-Deficit/Hyperactivity Disorder Knowledge Is Responsive to Decision Aid on Treatment for Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

Adapt and test a measure of knowledge for caregivers of children with attention-deficit/hyperactivity disorder (ADHD) and evaluate the impact of the information component of a decision aid (DA) on participant knowledge.

METHODS

A set of seven knowledge items were created based on prior knowledge measures and clinical guidelines. As part of a larger cross-sectional survey study of caregivers of children diagnosed with ADHD, caregivers were randomized to one of two arms: 1) a DA arm, where participants reviewed the information component of the Cincinnati Children's Hospital's DA, and 2) a control arm, where participants were not shown a DA. All participants completed the seven knowledge items. Knowledge items were assessed for difficulty, quality of distractors, acceptability, and redundancy. Total knowledge scores (0-100) for the DA and control arm were compared.

RESULTS

Caregivers were assigned to the DA arm (n = 243) or the control arm (n = 260). All 7 knowledge items were retained as no items were too difficult or too easy, all response options were used, there were little missing data, and no items were redundant. The overall knowledge score was normally distributed, and almost covered the full range of scores (5-100). Those who received the DA component had higher knowledge scores (M=68, SD=23) than those who did not receive the DA component (M=60, SD=19, P < .01, d=0.4).

CONCLUSIONS

The Caregiver ADHD Knowledge (CAKe) measure was acceptable and demonstrated construct validity as those who were assigned to review the DA component demonstrated greater knowledge than those who were not assigned to review the DA component.

Shared Decision Making for Elective Surgical Procedures in Older Adults with and without Cognitive Insufficiencies

PURPOSE

Older adults are prone to cognitive impairment, which may affect their ability to engage in aspects of shared decision making (SDM) and their ability to complete surveys about the SDM process. This study examined the surgical decision-making processes of older adults with and without cognitive insufficiencies and evaluated the psychometric properties of the SDM Process scale.

METHODS

Eligible patients were 65 y or older and scheduled for a preoperative appointment before elective surgery (e.g., arthroplasty). One week before the visit, staff contacted patients via phone to administer the baseline survey, including the SDM Process scale (range 0-4), SURE scale (top scored), and the Montreal Cognitive Assessment Test version 8.1 BLIND English (MoCA-blind; score range 0-22; scores < 19 indicate cognitive insufficiency). Patients completed a follow-up survey 3 mo after their visit to assess decision regret (top scored) and retest reliability for the SDM Process scale.

RESULTS

Twenty-six percent (127/488) of eligible patients completed the survey; 121 were included in the analytic data set, and 85 provided sufficient follow-up data. Forty percent of patients (n = 49/121) had MoCA-blind scores indicating cognitive insufficiencies. Overall SDM Process scores did not differ by cognitive status (intact cognition x ¯  = 2.5, s = 1.0 v. cognitive insufficiencies x ¯  = 2.5, s = 1.0; P = 0.80). SURE top scores were similar across groups (83% intact cognition v. 90% cognitive insufficiencies; P = 0.43). While patients with intact cognition had less regret, the difference was not statistically significant (92% intact cognition v. 79% cognitive insufficiencies; P = 0.10). SDM Process scores had low missing data and good retest reliability (intraclass correlation coefficient = 0.7).

CONCLUSIONS

Reported SDM, decisional conflict, and decision regret did not differ significantly for patients with and without cognitive insufficiencies. The SDM Process scale was an acceptable, reliable, and valid measure of SDM in patients with and without cognitive insufficiencies.

HIGHLIGHTS

Forty percent of patients 65 y or older who were scheduled for elective surgery had scores indicative of cognitive insufficiencies.Patient-reported shared decision making, decisional conflict, and decision regret did not differ significantly for patients with and without cognitive insufficiencies.The Shared Decision Making Process scale was an acceptable, reliable, and valid measure of shared decision making in patients with and without cognitive insufficiencies.

Evaluation of the shared decision-making process scale in cancer screening and medication decisions

OBJECTIVES

Examine reliability and validity of the Shared Decision-Making (SDM) Process scale for cancer screening and medication decisions.

METHODS

Secondary data analysis from 6174 participants who made decisions about cancer screening (breast, colon or prostate) or medication (menopause, depression, hypertension or high cholesterol). Key measures included the SDM Process scale, decisional conflict, decision regret, and decision quality. Construct validity was examined by testing whether higher SDM Process scores were associated with lower regret, lower decisional conflict and higher decision quality. Meta-analyses summarized data across studies. Some studies assessed the scale's reliability.

RESULTS

Average SDM Process scores ranged from 1.2 to 2.5. There was a moderate-to-large, positive association between scores and lack of decisional conflict (cancer screening: d=0.61, CI(0.38, 0.84), p < .001; medications: d=0.36, CI(0.29, 0.44), p < .001). High scores were associated with lower decision regret (cancer screening: d=-0.24, CI(-0.37, -0.11), p < .001; medications: d=-0.30, CI(-0.40,-0.20), p < .001). There was no relationship with decision quality. Retest reliability was acceptable (ICC>0.7) for seven of eight clinical samples.

CONCLUSIONS

The SDM Process scale demonstrated construct validity and retest reliability in cancer screening and medication decisions.

PRACTICE IMPLICATIONS

The validated SDM Process scale is a short, patient reported metric to evaluate the current state of SDM.

Pediatric Caregiver Version of the Shared Decision Making Process Scale: Validity and Reliability for ADHD Treatment Decisions

OBJECTIVE

Shared decision making (SDM) is recommended for common pediatric conditions; however, there are limited data on measures of SDM in pediatrics. This study adapted the SDM Process scale and examined validity and reliability of the scale for attention-deficit/hyperactivity disorder (ADHD) treatment decisions.

METHODS

Cross-sectional survey of caregivers (n = 498) of children (aged 5-13) diagnosed with ADHD, who had made a decision about ADHD medication in the last 2 years. Surveys included the adapted SDM Process scale (scores range 0-4, higher scores indicate more SDM), decisional conflict, decision regret, and decision involvement. Validity was assessed by testing hypothesized relationships between these constructs. A subset of participants was surveyed a week later to assess retest reliability.

RESULTS

Pediatric Caregiver version of the SDM Process scale (M = 2.8, SD = 1.05) showed no evidence of floor or ceiling effects. The scale was found to be acceptable (<1% missing data) and reliable (intraclass correlation coefficient = 0.74). Scores demonstrated convergent validity, as they were higher for those without decisional conflict than those with decisional conflict (2.93 vs 2.46, P < .001, d = 0.46), and higher for caregivers who stated they made the decision with the provider than those who made the decision themselves (3.0 vs 2.7; P = .003). Higher scores were related to less regret (r = -0.15, P < .001), though the magnitude of the relationship was small.

CONCLUSIONS

The adapted Pediatric Caregiver version of the SDM Process scale demonstrated acceptability, validity and reliability in the context of ADHD medication decisions made by caregivers of children 5-13. Scores indicate pediatricians generally involve caregivers in decision making about ADHD medication.

Shared Decision-Making Is Associated with Better Outcomes in Patients with Knee But Not Hip Osteoarthritis: The DECIDE-OA Randomized Study

BACKGROUND

Current guidelines recommend shared surgical decision-making, yet it is unclear whether shared decision-making improves health outcomes in patients who are considering knee and hip replacement. The purpose of the present study was to examine whether patients who made high-quality, informed, patient-centered (IPC) decisions had better health outcomes, higher satisfaction, and less decision regret compared with those who made lower-quality decisions.

METHODS

A multisite, randomized study of 2 decision aids for patients with hip and knee osteoarthritis was utilized to collect data on decision-making and health outcomes at 2 time points: shortly after the initial surgical evaluation and about 6 months after treatment. We calculated the percentage of patients who made an IPC decision and examined the a priori hypotheses that IPC decisions would be associated with better health outcomes, satisfaction, and less regret at 6 months. Linear and logistic regression models were utilized to examine the relationships.

RESULTS

The analytic sample included 854 patients with a mean age of 65 years (standard deviation, 9 years), of whom 58% were female, 93% were White non-Hispanic, 67% had knee (compared with hip) osteoarthritis, and 62% underwent operative treatment within 6 months of the initial evaluation. The majority of patients (68%) made IPC decisions. The IPC group had significantly larger gains in quality of life (mean difference in EuroQol-5 Dimension, 0.04; 95% confidence interval [CI], 0.02 to 0.07; p < 0.001) compared with the non-IPC group. For knee patients, the IPC group also had significantly better Knee injury and Osteoarthritis Outcome Scores (mean difference, 4.9; 95% CI, 1.5 to 8.3; p = 0.004), higher satisfaction (adjusted odds ratio [aOR], 1.7; 95% CI, 1.2 to 2.3; p = 0.003), much better pain relief (aOR, 2.1; 95% CI, 1.3 to 3.5; p = 0.002), and were more likely to have no decision regret (aOR, 2.3; 95% CI, 1.3 to 4.1; p = 0.003). For hip patients, IPC decisions were not associated with better Harris hip scores or satisfaction and were associated with more regret.

CONCLUSIONS

Higher-quality decisions predicted small improvements in health outcomes, as well as greater satisfaction and less regret for patients with knee osteoarthritis, but not for patients with hip osteoarthritis.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Using Standardized Videos to Examine the Validity of the Shared Decision Making Process Scale: Results of a Randomized Online Experiment

BACKGROUND

The Shared Decision Making (SDM) Process scale is a brief, patient-reported measure of SDM with demonstrated validity in surgical decision making studies. Herein we examine the validity of the scores in assessing SDM for cancer screening and medication decisions through standardized videos of good-quality and poor-quality SDM consultations.

METHOD

An online sample was randomized to a clinical decision-colon cancer screening or high cholesterol-and a viewing order-good-quality video first or poor-quality video first. Participants watched both videos, completing a survey after each video. Surveys included the SDM Process scale and the 9-item SDM Questionnaire (SDM-Q-9); higher scores indicated greater SDM. Multilevel linear regressions identified if video, order, or their interaction predicted SDM Process scores. To identify how the SDM Process score classified videos, area under the curve (AUC) was calculated. The correlation between SDM Process score and SDM-Q-9 assessed construct validity. Heterogeneity analyses were conducted.

RESULTS

In the sample of 388 participants (68% white, 70% female, average age 45 years) good-quality videos received higher SDM Process scores than poor-quality videos (Ps < 0.001), and those who viewed the good-quality high cholesterol video first tended to rate the videos higher. SDM Process scores were related to SDM-Q-9 scores (rs > 0.58; Ps < 0.001). AUC was poor (0.69) for the high cholesterol model and fair (0.79) for the colorectal cancer model. Heterogeneity analyses suggested individual differences were predictive of SDM Process scores.

CONCLUSION

SDM Process scores showed good evidence of validity in a hypothetical scenario but were lacking in ability to classify good-quality or poor-quality videos accurately. Considerable heterogeneity of scoring existed, suggesting that individual differences played a role in evaluating good- or poor-quality SDM conversations.

Are We Improving? Update and Critical Appraisal of the Reporting of Decision Process and Quality Measures in Trials Evaluating Patient Decision Aids

Background

In 2014, a systematic review found large gaps in the quality of reporting of measures used in 86 published trials evaluating the effectiveness of patient decision aids (PtDAs). The purpose of this study was to update that review.

Methods

We examined measures of decision making used in 49 randomized controlled trials included in the 2014 and 2017 Cochrane Collaboration systematic review of PtDAs. Data on development of the measures, reliability, validity, responsiveness, precision, interpretability, feasibility, and acceptability were independently abstracted by 2 paired reviewers.

Results

Information from 273 measures was abstracted, and 109 of these covered the core domains of decision processes (n = 55) and decision quality including informed choice/knowledge (n = 48) and values-choice concordance (n = 12). Very few studies reported data on the performance and clinical sensibility of measures, with reliability (23%) and validity (6%) being the most common. Studies using new measures were less likely to include information about their psychometric performance compared with previously published measures.

Limitations

The review was limited to reporting of measures in studies included in the Cochrane review and did not consult prior publications.

Conclusion

There continues to be very little reported about the development or performance of measures used to evaluate the effectiveness of PtDAs in published trials. Minimum reporting standards have been published, and efforts to require investigators to use them are needed.

Development and Evaluation of the Shared Decision Making Process Scale: A Short Patient-Reported Measure

BACKGROUND

The Shared Decision Making (SDM) Process scale is a short patient-reported measure of the amount of SDM that occurs around a medical decision. SDM Process items have been used previously in studies of surgical decision making and exhibited discriminant and construct validity.

METHOD

Secondary data analysis was conducted across 8 studies of 11 surgical conditions with 3965 responses. Each study contained SDM Process items that assessed the discussion of options, pros and cons, and preferences. Item wording, content, and number of items varied, as did inclusion of measures assessing decision quality, decisional conflict (SURE scale), and regret. Several approaches for scoring, weighting, and the number of items were compared to identify an optimal approach. Optimal SDM Process scores were compared with measures of decision quality, conflict, and regret to examine construct validity; meta-analysis generated summary results.

RESULTS

Although all versions of the scale were highly correlated, a short, partial credit, equally weighted version of the scale showed favorable properties. Overall, higher SDM Process scores were related to higher decision quality (d = 0.18, P = 0.029), higher SURE scale scores (d = 0.57, P < 0.001), and lower decision regret (d = -0.34, P < 0.001). Significant heterogeneity was present in all validity analyses.

LIMITATIONS

Included studies all focused on surgical decisions, several had small sample sizes, and many were retrospective.

CONCLUSION

SDM Process scores showed resilience to coding changes, and a scheme using the short, partial credit, with equal weights was adopted. The SDM Process scores demonstrated a small, positive relationship with decision quality and were consistently related to lower decision conflict and less regret, providing evidence of validity across several surgical decisions.

Validation of the Impact Index: can we measure disease effects on quality of life in patients with hip and knee osteoarthritis?

PURPOSE

To validate the Impact Index, a short, publicly available scale that measures the extent to which a respondent's health problem adversely impacts their quality of life.

METHODS

Secondary analysis of patients with hip or knee osteoarthritis surveyed after visiting a surgeon at baseline (N = 322) and about 6 months after the visit (N = 283). Patients responded to the Impact Index and previously validated questionnaires about overall health, pain, and function. The Impact Index includes four questions that ask how much the respondent is bothered, worried, limited, or in pain due to their health condition over the past 30 days. Total scores range from 0 to 12; higher scores indicate more deleterious impact.

RESULTS

Patients were mostly female (55%), majority white (95%), had an average age of 65 (SD = 9), and most had surgery (64%). The baseline Impact Index score was 9.48 (SD = 2.63); at follow up 4.75 (SD = 3.54). Impact Index was related to overall health at baseline (r =  - 0.49). For knee patients at baseline, Impact Index was negatively related to their knee symptoms (r =  - 0.49) and knee pain (r =  - 0.67). For hip patients at baseline, Impact Index was negatively related to the Harris Hip score (r =  - 0.62). Scale directions varied; however, the signs of all correlations were as hypothesized. The Impact Index was predictive of surgical choice (p < .001, OR = 1.45), however, overall health (p = .88) and comorbidity (p = .24) measures were not. Reliability was acceptable (α = 0.85). Responsiveness statistics suggested overall health, pain, function, and Impact Index measures reflected improvement patients experienced from surgery. The Impact Index had the largest effect sizes (> - 3.4) and Guyatt Responsiveness Statistics (> - 2.3).

CONCLUSIONS

The Impact Index demonstrated strong evidence of validity, reliability, and responsiveness in hip or knee osteoarthritis patients.

Decision Support Strategies for Hip and Knee Osteoarthritis: Less Is More: A Randomized Comparative Effectiveness Trial (DECIDE-OA Study)

BACKGROUND

As guidelines and payers increasingly recommend use of patient decision aids (DAs), evidence about the comparative effectiveness of available DAs is critical for organizations interested in implementing them. The primary purpose of this study was to compare 2 DAs with regard to their ability to help patients become informed and receive their preferred treatment (that is, make an informed patient-centered decision), shared decision-making, surgical rates, and surgeon satisfaction.

METHODS

We performed a multisite factorial randomized trial enrolling patients with hip or knee osteoarthritis. Patients were randomly assigned to use a long, detailed DA (long DA) or short, interactive DA (short DA). Eight surgeons were randomly assigned to receive a patient preference report detailing the patient's goals and treatment preferences or to administer usual care.

RESULTS

We distributed 1,636 pre-visit surveys, 1,220 of which were returned (75% response rate), and 1,124 post-visit surveys, 967 of which were returned (86% response rate). The patients in the sample had a mean age (and standard deviation) of 65 ± 10 years, 57% were female, 89% were white non-Hispanic, and 67% had knee osteoarthritis. The majority (67.2%) made informed patient-centered decisions, and the rate did not vary significantly between the DA groups (p = 0.97) or between the surgeon groups (p = 0.23). Knowledge scores were higher for the short-DA group (mean difference = 9%; p < 0.001). More than half of the sample (60.5%) had surgery within 6 months after the visit, and rates did not differ significantly by DA or surgeon group. Overall, the surgeons were highly satisfied and reported that the majority (88.7%) of the visits were of normal duration or shorter.

CONCLUSIONS

The DECIDE-OA study is, to our knowledge, the first randomized comparative effectiveness study of 2 orthopaedic DAs. The short DA outperformed the long DA with regard to knowledge scores and was comparable with respect to other outcomes. The surgeons reported high satisfaction and normal visit duration with both DAs.

CLINICAL RELEVANCE

Surgeons need to ensure that patients with osteoarthritis are well-informed and have a clear preference regarding whether to undergo hip or knee replacement surgery. The DAs used in this study may help surgeons involve patients in elective surgery decisions and meet the requirements of informed consent.

Protocol for a randomised trial evaluating the comparative effectiveness of strategies to promote shared decision making for hip and knee osteoarthritis (DECIDE-OA study)

INTRODUCTION

There are several different interventions available to promote shared decision making (SDM); however, little is known about the comparative effectiveness of different approaches.

OBJECTIVE

To examine the impact of patient-directed and physician-directed decision support strategies on the quality of treatment decisions for hip and knee osteoarthritis (OA).

TRIAL DESIGN

A 2×2 factorial randomised controlled trial.

SETTING

One academic medical centre, one community hospital and one orthopaedic specialty hospital.

PARTICIPANTS AND INTERVENTIONS

The enrolment targets were 8 surgeons and 1120 patients diagnosed with hip or knee OA. Patients were randomly assigned to receive one of two different decision aids (DAs) stratified by site. The DAs varied in length, content and the level of detail regarding treatment options. Both DAs were available by paper or online.Surgeons were randomly assigned to receive a report detailing patients' goals and treatment preferences at the time of the visit or not. Eligible patients received their assigned DA before their visit and completed three surveys: before the visit (timepoint (T)1), 1-week postvisit (T2) and 6 months from either the visit date or surgery date for patients who underwent surgery (T3). Study staff and participating surgeons were not blinded, but the statistician conducting the analyses was blinded to the arms.

MAIN OUTCOME MEASURE AND ANALYSIS

The primary study outcome was decision quality, the percentage of patients who were well informed and received their preferred treatment. Secondary outcomes included involvement in decision making, surgical rates, health outcomes, decision regret and satisfaction. A logistic regression model with the generalised estimating equations approach was used to compare rates of decision quality between the groups and account for the clustering of patients within providers.

ETHICS AND DISSEMINATION

Ethics approval was obtained through the institutional review board at the main site. The findings will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02729831; Pre-results.

Standards for UNiversal reporting of patient Decision Aid Evaluation studies: the development of SUNDAE Checklist

BACKGROUND

Patient decision aids (PDAs) are evidence-based tools designed to help patients make specific and deliberated choices among healthcare options. The International Patient Decision Aid Standards (IPDAS) Collaboration review papers and Cochrane systematic review of PDAs have found significant gaps in the reporting of evaluations of PDAs, including poor or limited reporting of PDA content, development methods and delivery. This study sought to develop and reach consensus on reporting guidelines to improve the quality of publications evaluating PDAs.

METHODS

An international workgroup, consisting of members from IPDAS Collaboration, followed established methods to develop reporting guidelines for PDA evaluation studies. This paper describes the results from three completed phases: (1) planning, (2) drafting and (3) consensus, which included a modified, two-stage, online international Delphi process. The work was conducted over 2 years with bimonthly conference calls and three in-person meetings. The workgroup used input from these phases to produce a final set of recommended items in the form of a checklist.

RESULTS

The SUNDAE Checklist (Standards for UNiversal reporting of patient Decision Aid Evaluations) includes 26 items recommended for studies reporting evaluations of PDAs. In the two-stage Delphi process, 117/143 (82%) experts from 14 countries completed round 1 and 96/117 (82%) completed round 2. Respondents reached a high level of consensus on the importance of the items and indicated strong willingness to use the items when reporting PDA studies.

CONCLUSION

The SUNDAE Checklist will help ensure that reports of PDA evaluation studies are understandable, transparent and of high quality. A separate Explanation and Elaboration publication provides additional details to support use of the checklist.

Explanation and elaboration of the Standards for UNiversal reporting of patient Decision Aid Evaluations (SUNDAE) guidelines: examples of reporting SUNDAE items from patient decision aid evaluation literature

This Explanation and Elaboration (E&E) article expands on the 26 items in the Standards for UNiversal reporting of Decision Aid Evaluations guidelines. The E&E provides a rationale for each item and includes examples for how each item has been reported in published papers evaluating patient decision aids. The E&E focuses on items key to reporting studies evaluating patient decision aids and is intended to be illustrative rather than restrictive. Authors and reviewers may wish to use the E&E broadly to inform structuring of patient decision aid evaluation reports, or use it as a reference to obtain details about how to report individual checklist items.

Notch3 cooperates with the EGFR pathway to modulate apoptosis through the induction of bim

Notch signaling is a highly conserved pathway important for normal embryonic development and cancer. We previously demonstrated a role for Notch3 in lung cancer pathogenesis. Notch3 inhibition resulted in tumor apoptosis and growth suppression. In vitro, these effects were enhanced when the epidermal growth factor receptor (EGFR) pathway was also inhibited, suggesting significant cross-talk between the two pathways. How Notch3 and epidermal growth factor receptor-mitogen-activated protein kinase (EGFR-MAPK) pathways cooperate in modulating apoptosis is not yet known. In this study, we provide evidence that Notch3 regulates Bim, a BH-3-only protein, via MAPK signaling. Furthermore, loss of Bim expression prevents tumor apoptosis induced by Notch3 inhibition. Using gamma-secretase inhibitor and erlotinib in a xenograft model, Bim induction and tumor inhibition were observed to be enhanced compared with either agent alone, consistent with our previous observation of significant synergism between Notch and EGFR-ras-MAPK signaling. Thus, our data support the hypothesis that Notch3 not only has a crucial role in lung cancer through regulating apoptosis, but also cooperates with the EGFR-MAPK pathway in modulating Bim.

Transforming growth factor alpha up-regulates desmin expression during embryonic mouse tongue myogenesis

Myogenesis is determined by a set of myogenic differentiation factors that are, in turn, regulated by a number of peptide growth factors. During embryonic mouse tongue formation, transforming growth factor alpha (TGF alpha), epidermal growth factor (EGF), and their cognate receptor (EGFR) are co-expressed spatially and temporally with desmin, a muscle-specific structural protein. This investigation tested the hypothesis that TGF alpha directly regulates the myogenic program in developing tongue myoblasts. Mandibular processes from the first branchial arch of embryonic day 10.5 (E10.5) mouse embryos were microdissected and explanted into an organ culture system using serumless chemically defined medium. Exogenous TGF alpha at 10 and 20 ng/ml specifically increased the amount of desmin expression and the number of desmin-positive cells without affecting the general growth and development of the mandibles. This inductive response was detected as early as 2 days after treatment and sustained up to 9 days in culture. EGFR antisense oligonucleotides (30 microM) as well as tyrphostin (80 microM) were able to negate TGF alpha-induced up-regulation of desmin expression. These data indicate that autocrine and/or paracrine action of TGF alpha promotes tongue myogenesis, and that this action is mediated through functional kinase activity of the EGFR. We speculate that the myogenic program in the developing mouse tongue is dependent upon growth factor mediated cell-cell communication of mesenchymal cells originating from the occipital somites and ectomesenchymal cells originating from the cranial neural crest.

Induced expression of myoD, myogenin and desmin during myoblast differentiation in embryonic mouse tongue development

Significant progress has been made in defining mechanisms governing myogenesis at the transcriptional levels, but the extracellular signal-transduction pathways involved in myogenesis are not as yet defined. The developing mouse tongue provides a model for the regulation of myogenesis during precise time periods in embryogenesis. The molecular cues that regulate the close-range autocrine and/or paracrine signalling processes required for the fast-twitch complex tongue musculature are not known. This study was designed to test the hypothesis that transforming growth factor-alpha (TGF alpha) controls myogenesis in embryonic mouse tongue through the induction of myogenic regulatory factors such as myoD, myf5, myogenin and MRF4/myf6/herculin. To test this hypothesis, the effects of exogenous TGF alpha on the transcription of myoD, myf5, myogenin, MRF4 and desmin were examined in tongue samples from embryonic day-10.5 mandibular explants cultured in serum-free, chemically defined medium and then processed for competitive, reverse transcription-polymerase chain reaction. TGF alpha induced myoD, myogenin and desmin expression. Treatment with 20 and 40 ng/ml TGF alpha decreased or downregulated myf5 mRNA. MRF4 was not detected in the explants. TGF alpha apparently induces the early developmental stages of myogenesis through sequential upregulation of myoD and myogenin, downregulation of myf5 and corresponding significant increases in muscle-specific gene expression such as desmin transcription.

Equus caballus gelsolin--cDNA sequence and protein structural implications

We have generated and characterized the cDNA from equine smooth muscle that encodes gelsolin, an actin-modulating protein. Overlapping cDNA clones synthesized by the reverse transcriptase/polymerase chain reaction and clones isolated from a horse genomic library provided the complete primary structure for the intracellular isoform of gelsolin, while cDNA complemented with protein sequence data produced the full-length primary transcript of the gelsolin isoform found circulating in equine plasma. The deduced amino acid sequences of the intracellular and secreted versions of equine gelsolin infer polypeptides of 731 and 755 residues with apparent molecular masses of 80.7 kDa and 83.2 kDa, respectively. Multiple sequence alignment analysis of equine, human, porcine, and murine orthologs of gelsolin demonstrates prominent similarities among all of these proteins, with the horse and human molecules exhibiting the largest degree of likeness with respect to polypeptide length and overall sequence composition. Both horse and human plasma gelsolins are comprised of 755 amino acids with 94% of the residues identical, while the degree of sequence identity in the shorter (731 residues) cytoplasmic gelsolins is 95%. Analysis of the sequences and structures of the six related domains that comprise gelsolin emphasizes the strong correlation that exists between primary structural conservation among mammalian gelsolins and maintenance of the three-dimensional domain fold characteristic of members of this protein family.

Timing of the expression of enamel gene products during mouse tooth development

In order to understand the mechanisms involved in tooth development it is important to define the timing for tissue-specific gene expression. A consequence of ameloblast cell differentiation is the sequential expression of tissue-specific genes whose products form the enamel extracellular matrix. The ameloblast phenotype has been characterized as consisting of two major classes of proteins: amelogenins and non-amelogenin proteins such as anionic enamel proteins (enamelins, tuft proteins, tuftelin, sulfated proteins) and enamel proteases. The postulated functions for the anionic enamel proteins are as nucleators for hydroxyapatite crystal formation while amelogenins control the crystal size, growth and orientation. While the amelogenins have been well characterized, detailed knowledge for anionic enamel proteins has been sparse. In the present study, we designed experiments to characterize one of the anionic enamel proteins from mouse molars, tuftelin, and to determine the timing of expression of this protein during molar tooth development. Our results showed the initial detection of tuftelin transcripts within proliferating inner enamel epithelial cells at very early stages of tooth development (13 days of embryonic development equivalent to the bud stage of tooth development). These data provide direct evidence that invalidates previous dogmas that enamel proteins were synthesized by polarized, non-dividing, fully differentiated ameloblast cells. In addition, tuftelin was found to be synthesized also by dental papilla mesenchyme cells suggesting that this protein is not enamel-specific. These data taken together open the possibility that the tuftelin present in the dentino-enamel junction could be secreted by both, preodontoblast cells and preameloblast cells. It might also suggest a possible different role for tuftelin than nucleator of hydroxyapatite crystals.

Coincident plasma ACTH and corticosterone time series: comparisons between young and old rats

Senescence is accompanied by a reduced ability to respond to a variety of physical and behavioral stressors. A sizable literature has been devoted to the interplay between hypothalamic-pituitary-adrenocortical axis dysfunction and senescence; yet, the precise interactions remain an enigma. Adrenocorticotropic hormone (ACTH) is secreted in pulsatile bursts generating complex signals in the plasma compartment that must be "read" by adrenocortical cells in order to initiate appropriate secretory responses. We have previously demonstrated subtle differences between young and old rats in the pattern of fluctuations in plasma ACTH concentrations over time, despite no difference in mean levels. The present work addressed the physiological significance of these differences in the plasma ACTH signal by analyzing the corresponding plasma corticosterone concentration time series and the relationship between these two hormones over time. Time series of integrated 10-min ACTH and corticosterone concentrations were collected over 4 h at the time of diurnal activation and analyzed in the time and frequency domains. The time of onset of the diurnal surge occurred 20 min later in old rats, and the ratio of corticosterone to ACTH was less at the time of onset and peak of the diurnal surge. Corticosterone levels were lower in old rats and mean ACTH and corticosterone levels were correlated in young but not old rats, as were maximum levels of the two hormones. Cross-correlation of ACTH and corticosterone time series and comparison of spectra were consistent with smoother fluctuations in plasma corticosterone in old animals with less variability at time scales less than 55 min. We conclude that age may be associated with a delay in diurnal activation of the HPA axis, a loss of sensitivity of adrenal corticosterone secretion to plasma ACTH levels, and a relative loss of high frequency variability in the corticosterone signal, as seen in many physiological systems with age.

Silicon analysis in biological specimens by direct current plasma-atomic emission spectroscopy

A method for the determination of total elemental silicon concentrations in biological fluids by direct current plasma-atomic emission spectrometry (DCP-AES) is presented. The method is linear up to 30 micrograms/mL in blood, serum, plasma, and urine, with a detection limit of 0.2 microgram/mL. Population ranges of silicon concentration in blood, plasma, serum, and urine were found to be less than 0.3 to 33 micrograms/mL, less than 0.4 to 39 micrograms/mL, less than 0.2 to 68 micrograms/mL, and less than 0.3 to 180 micrograms/mL, respectively. Over 50% of all measured concentrations were less than 0.5 microgram/mL for blood, plasma, and serum. Estimates of "normal" population ranges are reported, and potential applicability of this procedure to silicone-related maladies is discussed.

High intensity venous sampling reveals subtle alterations in plasma adrenocorticotropin patterns in old rats

Dysregulation of the hypothalamic-pituitary-adrenocortical axis has been theoretically linked to the processes of aging for decades. To investigate the effects of age on high frequency rhythms of plasma ACTH at the time of circadian activation, integrated 2-min blood samples were collected over 4 h in 10 young and 14 old rats with simultaneous plasma volume replacement. Plasma ACTH time series were analyzed in the time and frequency domains. Relative to young rats, old rats had a significantly later onset of the diurnal surge, more spectral power (R2) at lower frequencies, a lack of correlation between the slope of the spectral background continuum and the R2 at periods less than approximately 11 min, a stretching of the time scale in the composite spectra by 18.5%, and an amplitude reduction of the major composite spectral peak by 31%. These findings support the existence of subtle, but significant, alterations in the pattern of plasma ACTH with age and a delayed response of the hypothalamic-pituitary-adrenocortical axis to circadian activation. The differences in spectra suggest a weaker coupling with age between the high frequency signal input (that may reflect depolarization of groups of corticotrophs) and the system response, which could account for the delay in onset of the diurnal surge seen in the time domain.

Quantitative assessment of the glandular activity of endocrine cells of gastrointestinal mucosae by computer-assisted analysis of ultrastructural images: methodology

A method is described for studying the morphological features of endocrine cells of gastrointestinal mucosae in man and some animal species by semi-automatic analysis of ultrastructural images. The method enables possible ultrastructural variations in gastrointestinal endocrine glandular cells of different types to be determined with an acceptable margin of error. Various causes of error are investigated. It is found that the main cause is the choice of microscope magnification, despite the corrections made. The factor of inconsistency in the reproducibility of measurements performed by several operators is also calculated.