Progranulin AAV gene therapy for frontotemporal dementia: translational studies and phase 1/2 trial interim results

GRN mutations cause progranulin haploinsufficiency, which eventually leads to frontotemporal dementia (FTD-GRN). PR006 is an investigational gene therapy delivering the granulin gene (GRN) using an adeno-associated virus serotype 9 (AAV9) vector. In non-clinical studies, PR006 transduced neurons derived from induced pluripotent stem cells of patients with FTD-GRN, resulted in progranulin expression and improvement of lipofuscin, lysosomal and neuroinflammation pathologies in Grn-knockout mice, and was well tolerated except for minimal, asymptomatic dorsal root ganglionopathy in non-human primates. We initiated a first-in-human phase 1/2 open-label trial. Here we report results of a pre-specified interim analysis triggered with the last treated patient of the low-dose cohort (n = 6) reaching the 12-month follow-up timepoint. We also include preliminary data from the mid-dose cohort (n = 7). Primary endpoints were safety, immunogenicity and change in progranulin levels in cerebrospinal fluid (CSF) and blood. Secondary endpoints were Clinical Dementia Rating (CDR) plus National Alzheimer's Disease Coordinating Center (NACC) Frontotemporal Lobar Degeneration (FTLD) rating scale and levels of neurofilament light chain (NfL). One-time administration of PR006 into the cisterna magna was generally safe and well tolerated. All patients developed treatment-emergent anti-AAV9 antibodies in the CSF, but none developed anti-progranulin antibodies. CSF pleocytosis was the most common PR006-related adverse event. Twelve serious adverse events occurred, mostly unrelated to PR006. Deep vein thrombosis developed in three patients. There was one death (unrelated) occurring 18 months after treatment. CSF progranulin increased after PR006 treatment in all patients; blood progranulin increased in most patients but only transiently. NfL levels transiently increased after PR006 treatment, likely reflecting dorsal root ganglia toxicity. Progression rates, based on the CDR scale, were within the broad ranges reported for patients with FTD. These data provide preliminary insights into the safety and bioactivity of PR006. Longer follow-up and additional studies are needed to confirm the safety and potential efficacy of PR006. ClinicalTrials.gov identifier: NCT04408625 .

Development of a NASA roadmap for planetary protection to prepare for the first human missions to Mars

As part of planning for future space exploration, COSPAR (The Committee on Space Research) together with participating space agencies, organized and held interdisciplinary meetings to consider next steps in addressing knowledge gaps for planetary protection for future human missions to Mars. Beginning with the results of these meetings and earlier work by NASA, ESA, and COSPAR (e.g., Criswell et al., 2005; Hogan et al., 2006; Rummel et al., 2008) as a base the authors of this paper carried out a follow-on NASA planning activity to identify the necessary steps to be accomplished to close knowledge gaps. We identified significant overlap between the planetary protection needs and other sets of Mars preparation roadmaps (1) microbial monitoring requirements for crew health and medical systems, (2) studies of the microbiome of the built environment, (3) environmental control and life support systems (ECLSS), (4) waste management, and (5) planetary surface operations. In many cases, efforts to mature exploration class systems for Mars that are occurring in other domains can be leveraged with minor changes to address planetary protection gaps as well. In other cases, work planned for testing on the International Space Station (ISS) as an analog for crew Mars transit, or on the lunar surface as an analog for Mars surface operations can be used to close planetary protection technology and knowledge gaps. An overall strategic framework that combines these domains has the advantage of being more comprehensive, efficient, and timely for closing gaps. This approach has led to the development of a NASA roadmap for addressing planetary protection integrated with other related roadmaps. NASA's development and execution of the planetary protection is now viewed in an integrated way with related technology development and testing. Key features of the integrated capabilities roadmap include.

Improving Mobility Practices of Critically Ill Children

INTRODUCTION

This quality improvement project aimed to improve mobility practices in a pediatric intensive care unit.

METHOD

Three interventions were implemented: a staff-developed mobility progression guideline (including patient mobility phase identification using animal images), physical therapy (PT), and occupational therapy (OT) referrals for all patients with expected hospitalizations of more than 3 days, and the use of activity goal posters. The frequency of mobility activities performed, the number of PT and OT referrals and nurses' confidence in mobilizing patients were compared before and after project implementation.

RESULTS

Improvements occurred in the median number of daily mobility activities per patient encounter (1.5-4.0), number of PT and OT referrals (43% and 61% increase, respectively), and nurses' confidence in mobilizing patients (69% of clinical nurses agreed their confidence in mobilizing patients improved after protocol implementation).

DISCUSSION

Implementation of an interprofessional mobility quality improvement project improved mobility practices in the pediatric intensive care unit.

BACE inhibition causes rapid, regional, and non-progressive volume reduction in Alzheimer's disease brain

In the phase 3 EPOCH trial (Clinicaltrials.gov; NCT01739348), treatment with the BACE inhibitor verubecestat failed to improve cognition in patients with mild-to-moderate Alzheimer's disease, but was associated with reduced hippocampal volume after 78 weeks as assessed by MRI. The aims of the present exploratory analyses were to: (i) characterize the effect of verubecestat on brain volume by evaluating the time course of volumetric MRI changes for a variety of brain regions; and (ii) understand the mechanism through which verubecestat might cause hippocampal (and other brain region) volume loss by assessing its relationship to measures of amyloid, neurodegeneration, and cognition. Participants were aged 55-85 years with probable Alzheimer's disease dementia and a Mini Mental State Examination score ≥15 and ≤26. MRIs were obtained at baseline and at Weeks 13, 26, 52 and 78 of treatment. MRIs were segmented using Freesurfer and analysed using a tensor-based morphometry method. PET amyloid data were obtained with 18F-flutemetamol (Vizamyl®) at baseline and Week 78. Standardized uptake value ratios were generated with subcortical white matter as a reference region. Neurofilament light chain in the CSF was assessed as a biomarker of neurodegeneration. Compared with placebo, verubecestat showed increased MRI brain volume loss at Week 13 with no evidence of additional loss through Week 78. The verubecestat-related volumetric MRI loss occurred predominantly in amyloid-rich brain regions. Correlations between amyloid burden at baseline and verubecestat-related volumetric MRI reductions were not significant (r = 0.05 to 0.26, P-values > 0.27). There were no significant differences between verubecestat and placebo in changes from baseline in CSF levels of neurofilament light chain at Week 78 (increases of 7.2 and 14.6 pg/ml for verubecestat versus 19.7 pg/ml for placebo, P-values ≥ 0.1). There was a moderate correlation between volumetric MRI changes and cognitive decline in all groups including placebo at Week 78 (e.g. r = -0.45 to -0.55, P < 0.001 for whole brain), but the correlations were smaller at Week 13 and significant only for the verubecestat groups (e.g. r = -0.15 and -0.11, P < 0.04 for whole brain). Our results suggest that the verubecestat-associated MRI brain volume loss is not due to generalized, progressive neurodegeneration, but may be mediated by specific effects on BACE-related amyloid processes.

Associations between childhood cancer treatment and tooth agenesis

AIM

The aim of this study was to determine the prevalence of dental developmental disturbances in long-term survivors of childhood malignancies in New Zealand children. This study reports associations with potential risk factors to inform oncologists and dentists of the likelihood of dental abnormalities.

METHODS

The study population was children aged 14-16 years old who were diagnosed with cancer prior to 10 years of age. A total of 156 children were eligible, of which 59 participated in this study. The indices used in this study were Holtta's Defect Index (HDI), and Oral Health Impact Profile-14 (OHIP-14).

RESULTS

The prevalence of agenesis was 15.3%, microdontia 6.8% and root abnormalities 32.2%. Cyclophosphamide equivalent doses above 8,000mg/m2, stem cell therapy (SCT), and head and neck radiation therapy (HNRT) were associated with a higher mean number of teeth missing due to agenesis. SCT and HNRT were associated with a higher total HDI. A binary logistic regression was carried out to determine the odds of agenesis and found that HNRT was the main contributing factor (OR=7.7, p-value=0.04). The linear regression model found that dactinomycin and agenesis correlated with the largest mean OHIP-14.

CONCLUSION

This study found that childhood cancer survivors in New Zealand had a high prevalence of developmental dental abnormalities and it identified potential risk factors related to their cancer treatment. Inequitable access to oral rehabilitation for this patient group argues for a mechanism for consistent improved access to publicly funded dental care across district health boards in New Zealand.

A Performance Improvement Initiative for Implementing an Evidence-Based Discharge Bundle for Lung Transplant Recipients

BACKGROUND

Lung transplant recipients have high hospital readmission rates. Readmissions are costly to institutions and associated with higher mortality among patients within the first year of transplant. Strong evidence indicates that in hospitalized patients, the use of discharge bundles results in lower 30-day hospital readmission rates.

LOCAL PROBLEM

A lung transplant team at a Midwest academic medical center performs 40 to 50 lung transplants annually and provides comprehensive, ongoing care for approximately 300 lung transplant recipients. The objective of this quality improvement project was development and implementation of an evidence-based discharge bundle (standardized patient discharge process) to reduce 30-day hospital readmission rates for this patient population.

METHODS

A gap analysis was performed using focus groups to identify strategies to reduce readmissions. Using that data, a standardized discharge bundle was developed in collaboration with the transplant team.

INTERVENTIONS

The discharge bundle included improvements in discharge planning, scripted communication methods between team members, a standardized medication template for patient education, standardized follow-up appointment process, and increased telephone calls to the patient after discharge.

RESULTS

The primary outcome measured was the monthly 30-day hospital readmission rate of facility lung transplant recipients from June through August of 2019 as compared to the same time period in 2018. The readmission rate did not change during the evaluation period. Team members reported improved communication, efficiency, and improved standardization of follow-up care using the discharge bundle.

CONCLUSIONS

Implementing a discharge bundle for lung transplant recipients resulted in improved staff satisfaction with the discharge process.

Further analyses of the safety of verubecestat in the phase 3 EPOCH trial of mild-to-moderate Alzheimer's disease

BACKGROUND

Verubecestat, a BACE1 inhibitor that reduces Aβ levels in the cerebrospinal fluid of humans, was not effective in a phase 3 trial (EPOCH) of mild-to-moderate AD and was associated with adverse events. To assist in the development of BACE1 inhibitors, we report detailed safety findings from EPOCH.

METHODS

EPOCH was a randomized, double-blind, placebo-controlled 78-week trial evaluating verubecestat 12 mg and 40 mg in participants with mild-to-moderate AD diagnosed clinically. The trial was terminated due to futility close to its scheduled completion. Of 1957 participants who were randomized and took treatment, 652 were assigned to verubecestat 12 mg, 652 to verubecestat 40 mg, and 653 to placebo. Adverse events and relevant laboratory, vital sign, and ECG findings were assessed.

RESULTS

Verubecestat 12 mg and 40 mg were associated with an increase in the percentage of participants reporting adverse events versus placebo (89 and 92% vs. 82%), although relatively few participants discontinued treatment due to adverse events (8 and 9% vs. 6%). Adverse events that were increased versus placebo included falls and injuries, suicidal ideation, weight loss, sleep disturbance, rash, and hair color change. Most were mild to moderate in severity. Treatment differences in suicidal ideation emerged within the first 3 months but did not appear to increase after 6 months. In contrast, treatment differences in falls and injuries continued to increase over time.

CONCLUSIONS

Verubecestat was associated with increased risk for several types of adverse events. Falls and injuries were notable for progressive increases over time. While the mechanisms underlying the increased adverse events are unclear, they may be due to BACE inhibition and should be considered in future clinical development programs of BACE1 inhibitors.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01739348 , registered on 29 November 2012.

Randomized Trial of Verubecestat for Prodromal Alzheimer's Disease

BACKGROUND

Prodromal Alzheimer's disease offers an opportunity to test the effect of drugs that modify the deposition of amyloid in the brain before the onset of dementia. Verubecestat is an orally administered β-site amyloid precursor protein-cleaving enzyme 1 (BACE-1) inhibitor that blocks production of amyloid-beta (Aβ). The drug did not prevent clinical progression in a trial involving patients with mild-to-moderate dementia due to Alzheimer's disease.

METHODS

We conducted a randomized, double-blind, placebo-controlled, 104-week trial to evaluate verubecestat at doses of 12 mg and 40 mg per day, as compared with placebo, in patients who had memory impairment and elevated brain amyloid levels but whose condition did not meet the case definition of dementia. The primary outcome was the change from baseline to week 104 in the score on the Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB; scores range from 0 to 18, with higher scores indicating worse cognition and daily function). Secondary outcomes included other assessments of cognition and daily function.

RESULTS

The trial was terminated for futility after 1454 patients had been enrolled; 485 had been assigned to receive verubecestat at a dose of 12 mg per day (the 12-mg group), 484 to receive verubecestat at a dose of 40 mg per day (the 40-mg group), and 485 to receive placebo. A total of 234 patients, 231 patients, and 239 patients per group, respectively, completed 104 weeks of the trial regimen. The estimated mean change from baseline to week 104 in the CDR-SB score was 1.65 in the 12-mg group, 2.02 in the 40-mg group, and 1.58 in the placebo group (P = 0.67 for the comparison between the 12-mg group and the placebo group and P = 0.01 for the comparison between the 40-mg group and the placebo group), suggesting a worse outcome in the higher-dose group than in the placebo group. The estimated rate of progression to dementia due to Alzheimer's disease was 24.5, 25.5, and 19.3 events per 100 patient-years in the 12-mg group, the 40-mg group, and the placebo group, respectively (hazard ratio for 40 mg vs. placebo, 1.38; 97.51% confidence interval, 1.07 to 1.79, not adjusted for multiple comparisons), favoring placebo. Adverse events were more common in the verubecestat groups than in the placebo group.

CONCLUSIONS

Verubecestat did not improve clinical ratings of dementia among patients with prodromal Alzheimer's disease, and some measures suggested that cognition and daily function were worse among patients who received verubecestat than among those who received placebo. (Funded by Merck Sharp & Dohme; ClinicalTrials.gov number, NCT01953601.).

Association between diverticular disease requiring surgical intervention and mortality in the postlung transplant population - a retrospective cohort study

Lung Transplant recipients are at increased risk of complicated diverticular disease. We aim to assess the rate of diverticular surgery in a postlung transplantation population and identify risk factors for surgery. We performed a retrospective cohort study of lung transplant recipients from 2007 to 2011. Demographic variables were evaluated with the Mann-Whitney U and chi-squared tests. Cox regression was performed to evaluate 1- and 2-year landmark survival, assess predictor variables of diverticular surgery and evaluate impact of surgery on CLAD development. Of 17 of 158 patients (10.7%) underwent diverticular-related surgery. Surgical patients had significantly worse survival than nonsurgical patients at 1 year [aHR 2.93 (1.05-8.21), P = 0.041] and 2 year [aHR 4.17 (1.26-13.84), P = 0.020] landmark analyses. Transplant indication of alpha-1 antitrypsin disease and cystic fibrosis were significantly associated with the need for diverticular surgery. Emergent surgery was associated with poorer survival [aHR 5.12(1.00-26.27), P = 0.050]. Lung transplant patients requiring surgery for complicated diverticular disease have significantly poorer survival than those who do not require surgery. Surgery was more common in patients transplanted for A1AT and CF. Optimal assessment and risk stratification of diverticular disease is necessary to prevent excessive morbidity and mortality following transplantation.

Randomized Trial of Verubecestat for Mild-to-Moderate Alzheimer's Disease

BACKGROUND

Alzheimer's disease is characterized by the deposition of amyloid-beta (Aβ) plaques in the brain. Aβ is produced from the sequential cleavage of amyloid precursor protein by β-site amyloid precursor protein-cleaving enzyme 1 (BACE-1) followed by γ-secretase. Verubecestat is an oral BACE-1 inhibitor that reduces the Aβ level in the cerebrospinal fluid of patients with Alzheimer's disease.

METHODS

We conducted a randomized, double-blind, placebo-controlled, 78-week trial to evaluate verubecestat at doses of 12 mg and 40 mg per day, as compared with placebo, in patients who had a clinical diagnosis of mild-to-moderate Alzheimer's disease. The coprimary outcomes were the change from baseline to week 78 in the score on the cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-cog; scores range from 0 to 70, with higher scores indicating worse dementia) and in the score on the Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory scale (ADCS-ADL; scores range from 0 to 78, with lower scores indicating worse function).

RESULTS

A total of 1958 patients underwent randomization; 653 were randomly assigned to receive verubecestat at a dose of 12 mg per day (the 12-mg group), 652 to receive verubecestat at a dose of 40 mg per day (the 40-mg group), and 653 to receive matching placebo. The trial was terminated early for futility 50 months after onset, which was within 5 months before its scheduled completion, and after enrollment of the planned 1958 patients was complete. The estimated mean change from baseline to week 78 in the ADAS-cog score was 7.9 in the 12-mg group, 8.0 in the 40-mg group, and 7.7 in the placebo group (P=0.63 for the comparison between the 12-mg group and the placebo group and P=0.46 for the comparison between the 40-mg group and the placebo group). The estimated mean change from baseline to week 78 in the ADCS-ADL score was -8.4 in the 12-mg group, -8.2 in the 40-mg group, and -8.9 in the placebo group (P=0.49 for the comparison between the 12-mg group and the placebo group and P=0.32 for the comparison between the 40-mg group and the placebo group). Adverse events, including rash, falls and injuries, sleep disturbance, suicidal ideation, weight loss, and hair-color change, were more common in the verubecestat groups than in the placebo group.

CONCLUSIONS

Verubecestat did not reduce cognitive or functional decline in patients with mild-to-moderate Alzheimer's disease and was associated with treatment-related adverse events. (Funded by Merck; ClinicalTrials.gov number, NCT01739348 .).

A Phase II Dose-Ranging Study Evaluating the Efficacy and Safety of the Orexin Receptor Antagonist Filorexant (MK-6096) in Patients with Primary Insomnia

BACKGROUND

Filorexant (MK-6096) is an orexin receptor antagonist; here, we evaluate the efficacy of filorexant in the treatment of insomnia in adults.

METHODS

A double-blind, placebo-controlled, randomized, two 4-week-period, adaptive crossover polysomnography study was conducted at 51 sites worldwide. Patients (18 to <65 years) with insomnia received 1 of 4 doses of oral filorexant (2.5, 5, 10, 20mg) once daily at bedtime during one period and matching placebo in the other period in 1 of 8 possible treatment sequences. Polysomnography was performed on night 1 and end of week 4 of each period. The primary endpoint was sleep efficiency at night 1 and end of week 4. Secondary endpoints included wakefulness after persistent sleep onset and latency to onset of persistent sleep.

RESULTS

A total of 324 patients received study treatment, 315 received ≥1 dose of placebo, and 318 ≥1 dose of filorexant (2.5mg, n=79; 5mg, n=78; 10mg, n=80; 20mg, n=81). All filorexant doses (2.5/5/10/20mg) were significantly superior to placebo in improving sleep among patients with insomnia as measured by sleep efficiency and wakefulness after persistent sleep onset on night 1 and end of week 4. The 2 higher filorexant doses (10/20mg) were also significantly more effective than placebo in improving sleep onset as measured by latency to onset of persistent sleep at night 1 and end of week 4. Filorexant was generally well tolerated.

CONCLUSIONS

Orexin receptor antagonism by filorexant significantly improved sleep efficiency in nonelderly patients with insomnia. Dose-related improvements in sleep onset and maintenance outcomes were also observed with filorexant.

The impact of sex and gender on adaptation to space: executive summary

This review article is a compendium of six individual manuscripts, a Commentary, and an Executive Summary. This body of work is entitled "The Impact of Sex and Gender on Adaptation to Space" and was developed in response to a recommendation from the 2011 National Academy of Sciences Decadal Survey, "Recapturing a Future for Space Exploration: Life and Physical Sciences for a New Era," which emphasized the need to fully understand sex and gender differences in space. To ensure the health and safety of male and female astronauts during long-duration space missions, it is imperative to examine and understand the influences that sex and gender have on physiological and psychological changes that occur during spaceflight. In this collection of manuscripts, six workgroups investigated and summarized the current body of published and unpublished human and animal research performed to date related to sex- and gender-based differences in the areas of cardiovascular, immunological, sensorimotor, musculoskeletal, reproductive, and behavioral adaptations to human spaceflight. Each workgroup consisted of scientists and clinicians from academia, the National Aeronautics and Space Administration (NASA), and other federal agencies and was co-chaired by one representative from NASA and one from the external scientific community. The workgroups met via telephone and e-mail over 6 months to review literature and data from space- and ground-based studies to identify sex and gender factors affecting crew health. In particular, the Life Sciences Data Archive and the Lifetime Surveillance of Astronaut Health were extensively mined. The groups identified certain sex-related differences that impact the risks and the optimal medical care required by space-faring women and men. It represents innovative research in sex and gender-based biology that impacts those individuals that are at the forefront of space exploration.

Long-term open-label safety study of rizatriptan acute treatment in pediatric migraineurs

OBJECTIVE

To evaluate the safety/tolerability of rizatriptan in the long-term acute treatment of migraine in pediatric patients.

BACKGROUND

Acute migraine treatment options for children are limited. A recent single-attack trial demonstrated that rizatriptan is effective in eliminating migraine headache pain in this population. We evaluated the long-term safety and efficacy of rizatriptan when used for intermittent acute treatment.

METHODS

Open-label study in pediatric migraineurs ages 12-17 years. Patients weighing <40 kg received rizatriptan (orally disintegrating tablet) 5 mg, and those weighing ≥40 kg received 10 mg. Patients could treat up to 8 mild/moderate/severe migraine attacks per month for up to 12 months. One dose of study medication was allowed in a 24-hour period.

RESULTS

A total of 674 patients were enrolled, and 606 patients were treated with study medication (N = 583 for 10 mg, N = 23 for 5 mg). The mean duration in the study was 292 days, and the mean number of doses of study medication taken was 20. Over the course of the study within 14 days post-any-dose, 66.0% (400) of the 606 treated patients had any adverse event, 2.3% (14) discontinued due to an adverse event, 2.6% (16) had a serious adverse event, and 23.4% (142) had a triptan-related adverse event. Of the 16 patients with serious adverse events within 14 days post-any-dose, the adverse events in 3 were considered drug-related; all 3 patient's adverse events were classified as serious only because they were associated with an overdose (use of >1 dose of study medication in a 24-hour period). The mean percentage of patient's attacks with pain freedom at 2-hours post-dose was 46.3%; this was relatively consistent over time (Months 1-3 = 43.7%, Months 4-6 = 51.9%, Months 7-9 = 49.9%, Months 10-12 = 49.5%).

CONCLUSION

Rizatriptan was generally safe and well tolerated in the long-term acute treatment of migraine in pediatric patients aged 12-17 years and demonstrated a consistent treatment effect over time.

Efficacy and tolerability of rizatriptan in pediatric migraineurs: Results from a randomized, double-blind, placebo-controlled trial using a novel adaptive enrichment design

Background

Treatment options for children and adolescents with migraine are limited. This study evaluated rizatriptan for the acute treatment of migraine in children and adolescents.

Methods

Randomized, double-blind, placebo-controlled, parallel-group trial in migraineurs 6–17 years old with unsatisfactory response to nonsteroidal anti-inflammatory drugs or acetaminophen/paracetamol. The trial included a double-blind run-in with weight-based rizatriptan dosing (5 mg for <40 kg, 10 mg for ≥40 kg). In the Stage 1 run-in, patients were randomized in a ratio of 20:1 placebo:rizatriptan and were instructed to treat within 30 minutes of a moderate/severe migraine. Patients with mild/no pain after 15 minutes of treatment (responders) took no further study medication, whereas patients with moderate/severe pain (non-responders) proceeded to take study medication in Stage 2. Non-responders who received placebo in Stage 1 were randomized 1:1 to rizatriptan:placebo, whereas non-responders who received rizatriptan in Stage 1 were allocated to placebo in Stage 2. The primary efficacy endpoint was pain freedom at 2 hours after Stage 2 dose in 12–17-year-olds.

Results

A higher proportion of 12–17-year-olds on rizatriptan had pain freedom at 2 hours compared with those on placebo: 87/284 (30.6%) versus 63/286 (22.0%), odds ratio = 1.55 [95% CI: 1.06 to 2.26], p = 0.025. Adverse events within 14 days of dose in 12–17-year-olds were similar for rizatriptan and placebo. The pattern of findings was similar in 6–17-year-olds.

Conclusion

Rizatriptan demonstrated a statistically significant improvement over placebo in eliminating pain and was generally well tolerated in migraineurs aged 12–17 and 6–17 years.

Trial Registration

ClinicalTrials.gov NCT01001234

Molar incisor hypomineralization

Molar Incisor Hypomineralization (MIH) is a common condition in New Zealand children and children around the world and can result in a significant defect in first permanent molars. This condition inevitably leads to a large amount of dental treatment for young children and may even result in the removal of their first permanent molars. This lecture will outline the understanding of the physical properties of these teeth and provide an evidence based review of the treatment options for affected teeth.

Micromechanical and Structural Analysis of Compromised Dental Tissues

With the continual development of new dental materials and treatment techniques, dental materials research is now more important than ever. Although the traditional method of materials and treatment technique assessment was laboratory based, there is a need for investigations into the clinical outcomes of in-vitro research. The aim of this paper is to discuss the micromechanical and structural analysis of compromised dental tissues that affect young children, using a biomaterial and clinical approach.

The role of FoxC1 in earlyXenopus development

FoxC1 is an important transcription factor in vertebrate development since its mutation in humans results in Axenfeld-Rieger syndrome. In the mouse, disturbance of its function causes congenital hydrocephalus and abnormalities in the development of various mesodermal derivatives. In this report, we provide one mechanistic basis for the requirement for FoxC1 in vertebrate development. We find that, in Xenopus laevis embryos, FoxC1 expression is regulated by the maternal T-box transcription factor VegT, via the nodal sub-family of TGFbeta signaling transducers. We show that at the late neurula to early tailbud stage, FoxC1 depletion causes the down-regulation of adhesion molecules, EP and E cadherin, as well as members of the Ephrin/EphR signaling families in the mesoderm germ layer resulting in the loss of adhesion and apoptosis of mesodermal cells.

Liquid-based cytology improves productivity in cervical cytology screening

OBJECTIVES

The ThinPrep test was introduced into our institution on a phased basis over 3 years between January 2002 and December 2004. This study set out to assess its effect on productivity (as measured by output of cases per medical scientist per day) during the changeover period. Numbers of high and low-grade lesions and of unsatisfactory slides were also monitored.

METHODS

The percentage conversion from conventional preparation to liquid-based cytology (LBC) and output of cases per medical scientist per day were calculated from our database at 6-month intervals. The average backlog, average number of cases received per month and percentage of unsatisfactory and abnormal cases were calculated similarly.

RESULTS

Over the study period 92 084 cases were received. The percentage of cases using ThinPrep increased: from 9% in January 2002 to 73% in December 2004. During the study there was an increase in output from 17.0 to 22.3 cases per medical scientist per day, representing a 31% improvement at 73% conversion. Numbers of unsatisfactory cases decreased substantially and the numbers of low and high-grade diagnoses were relatively constant.

CONCLUSIONS

The change to ThinPrep has improved productivity and decreased the number of unsatisfactory cases. There was no adverse effect on quality during the changeover.

Prevalence of enamel defects and MIH in non-fluoridated and fluoridated communities

AIM

This was to study the prevalence of enamel defects and molar incisor hypomineralisation (MIH) in children attending Leeds Dental Institute (UK) and Westmead Dental Hospital, Sydney (Australia).

METHODS

Prospective dental examinations were carried out on 25 children referred to two orthodontic departments. A questionnaire was completed to obtain background information and about previous fluoride (F) exposure followed by an oral examination. First permanent molars and permanent incisors were examined for presence, type and severity of enamel defects using the modified DDE screening index. Chi square tests were used to compare results.

RESULTS

Data for 24 children in Sydney and 20 in Leeds presented with at least one enamel defect. Of 300 teeth examined, 155 in Sydney and 82 in Leeds had a defect (p < 0.005). Severity of enamel defects was higher in Sydney. The children presenting with any type of enamel defect in at least one incisor or molar were 21 in Sydney and 10 in Leeds. However, if only demarcated defects were considered, the number in Sydney dropped to 11 and in Leeds remained at 10.

CONCLUSIONS

There was a higher prevalence of enamel defects in those children living in F Sydney than in non-F Leeds, but the prevalence of MIH was the same supporting the view that F is not associated with the aetiology of MIH.

Mechanical properties across hypomineralized/hypoplastic enamel of first permanent molar teeth

The aims of the present study were to investigate the mechanical properties of first permanent molars affected with enamel hypomineralization or hypoplasia, and to describe the appearance of these lesions under scanning electron microscopy. Eight first permanent molar test teeth and two unaffected premolars (controls) were enclosed in resin, then sectioned axially and polished. The hardness and modulus of elasticity was determined from a single array of indentations made parallel to the amelo-dentinal junction using an Ultra-Micro-Indentation system. The teeth were then examined using the scanning electron microscope. The mechanical properties of the test teeth in the unaffected cervical region (hardness and modulus range, 2.03-4.99 GPa and 50.39-96.87 GPa, respectively) were similar to those of the control enamel (hardness and modulus range, 2.71-4.15 GPa and 62.06-95.77 GPa, respectively). Between the unaffected cervical enamel and the hypomineralized region there was a transitional area of 500-600 microm where the mechanical properties in the experimental teeth decreased linearly. The mechanical properties of the hypomineralized region of each experimental tooth were significantly lower than those of the control or cervical regions (hardness and modulus range, 0.07-1.74 GPa and 3.26-40.96 GPa, respectively). The scanning electron microscopy views revealed disorganized enamel with poorly demarcated prism boundaries in the affected regions. In conclusion, the hardness and modulus of elasticity of hypomineralized enamel in first permanent molars is significantly less than in unaffected areas of the same tooth. The reason for this is unclear but may be related to the lack of organization of the enamel crystals.

Preliminary in vitro assessment of erosive potential using the ultra-micro-indentation system

The aim of this study was to measure the change in hardness and modulus of elasticity of enamel and dentine in primary teeth using the ultra-micro-indentation system (UMIS) after exposure to potentially erosive beverages and to relate the changes to the chemical composition of the test beverages. Primary molar teeth were sectioned and polished. Indentations were made in enamel and dentine prior to and then after exposure to one of four beverages: distilled water (control), orange juice, Orange Cordial, Fanta((R)) and a 'toothfriendly' Tropical Orange Cordial (Ribena((R))). Each beverage was then analysed. Fanta and Orange Cordial were the only test beverages to show a statistically significant reduction in the enamel hardness in comparison to the control and only Fanta showed a significant reduction in dentine hardness. None of the test beverages significantly reduced the modulus of elasticity of either enamel or dentine. Statistically the pH, phosphate and fluoride concentrations of the beverages were correlated with softening of enamel. Calcium concentration and titratable acidity were correlated with softening of dentine. The UMIS offers another method of measuring the basic mechanical properties of enamel and dentine. This is useful in predicting the erosive potential of substrates. It is likely that the pH, titratable acidity, fluoride, phosphate and calcium content of beverages are all important in determining the potential erosiveness of beverages.

The hardness and modulus of elasticity of primary molar teeth: an ultra-micro-indentation study

OBJECTIVE

Baseline information on the mechanical properties of and the effect of load upon dental hard tissue is important in the development of successful dental materials. Existing methods of measuring such properties of tissue are subject to significant experimental error. This study reports on the use of an Ultra-Micro-Indentation System (UMIS) to measure the hardness and elastic modulus of primary enamel and dentine.

METHODS

Primary molar teeth were sectioned, set in resin and polished. Thirty indentations were made in enamel and dentine using a Berkovitch indentor, 15 of which were subject to a load of 50mN and 15 to a load of 150mN. An automated computerised system converted the force/penetration graph for each indentation in to a hardness vs depth graph from which values for the mean hardness and elastic modulus were calculated.

RESULTS

Primary enamel had a mean hardness of 4.88+/-0.35GPa whilst the hardness of dentine was 0.92+/-0.11GPa The elastic modulus for enamel was 80.35+/-7.71GPa and that of dentine 19.89+/-1.92GPa. Using linear regression analysis a significant relationship could be shown between the hardness and the elastic modulus for both enamel and dentine when loaded to 150mN but only for dentine at 50mN (P<0.05). In general the elasticity of tooth structure increased as the hardness increased.

CONCLUSION

The UMIS offers a simple and reproducible method of measuring basic mechanical properties of small samples of enamel and dentine.

Targeting patients undergoing angioplasty for thrombus inhibition: a cost-effectiveness and decision support model

BACKGROUND

In recent clinical trials, glycoprotein IIb/IIIa blockers have demonstrated effectiveness in preventing adverse events after angioplasty in high-risk patients. However, uncertainty exists regarding the cost-effective selection of patients to receive antiplatelet therapy.

METHODS AND RESULTS

All 4962 patients at Emory University Hospitals who underwent coronary intervention procedures (n=6062) from 1993 to 1995 were studied. Multivariate models to predict death and the composite of death, Q-wave and non-Q-wave myocardial infarction, and emergency additional revascularization were developed. Hospital costs and professional costs were determined. A cost-effectiveness analysis with therapy targeted to high-risk patients was performed. If patients with a >5% probability of events received antiplatelet therapy that reduced events by 24% and cost $1000, 40.1% of patients would receive therapy; complications would be reduced from 6.39% to 5.37%, and cost would increase $261 from $10343 to $10604, or $25504 per event prevented. The marginal cost per event prevented by moving from a 7% to a 5% probability of an event cutoff would be $57 799.

CONCLUSIONS

For high-risk patients, there may be cost savings; for low-risk patients, therapy may not be cost effective; and for patients in the midrange (between 5% and 7% probability of an adverse event), events may be prevented at an acceptable level of cost.

Influence of age on outcome after percutaneous transluminal coronary angioplasty

This study estimates the influence of age on outcomes (mainly survival) of 21,516 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) between 1980 and 1996. We prospectively analyzed the patients in 5 age groups: <50, 50 to 59, 60 to 69, 70 to 79, and > or =80 years old. During the in-hospital period after PTCA, mortality increased from 0.28% in patients aged <50 to 3.45% in patients aged > or =80; Q-wave myocardial infarction was not significantly associated with age, and the 2 older groups were referred less often to coronary artery bypass graft surgery. During follow-up, lasting up to 10 years, the hazard of death was significantly influenced by age; Q-wave myocardial infarction was influenced by age, although the magnitude of the effect was relatively small and of questionable clinical significance; and coronary artery bypass graft surgery was performed less often in the 2 older age groups. Additional PTCA was similarly performed among the age groups. Age, diabetes mellitus, systemic hypertension, heart failure class, angioplasty in graft vessel, number of coronary vessels narrowed, and previous myocardial infarction were predictors of death over the 10-year follow-up. Age was the most important correlate of death after PTCA, with a 65% increase in the hazard of death for each 10-year increase in age. Age has an independent effect on early and late survival after PTCA.

Can cardiovascular clinical characteristics be identified and outcome models be developed from an in-patient claims database?

The objective of this study was to assess whether administrative (claims) databases can be used to assess clinical variables and predict outcome. Although administrative databases are useful for assessing resource utilization, their utility for assessing clinical information is less certain. Prospectively gathered clinical databases, however, are expensive and not widely available. The UB92 formulation of the hospital bill was used as an administrative source of data and compared with the clinical cardiovascular database at Emory University. The claims database was compared with the clinical database for 11 variables. Outcome models were developed with multivariate methods. A total of 11,883 patients who underwent catheterization (5,255 underwent percutaneous transluminal coronary angioplasty [PTCA] and 3,794 underwent coronary artery bypass surgery [CABG]) between 1991 and 1995 were included. For some variables, the claims database correlated well (diabetes, sensitivity 87%, specificity 99%), whereas for others the claims database was less accurate (peripheral vascular disease, sensitivity 20%, specificity 99%). Uncertain coding in the claims database, which can result in the same code being used for co-morbid states and severity of disease, as well as complications, limited the ability of claims to predict outcome. Clinical databases may also be limited by lack of objectivity and missing data. The utility of claims databases to assess severity of disease and co-morbid states is limited, and outcome modeling and risk assessment from claims databases may be inappropriate and spurious. Developing better data standards and less expensive methods for acquisition of clinical data is necessary for improved outcome assessment.

Persistent effects of prenatal, neonatal, or adult treatment with flutamide on the hypothalamic-pituitary-adrenal stress response of adult male rats

To explore the role of androgens in early development on adult hypothalamic-pituitary-adrenal (HPA) function in males, we administered flutamide or vehicle injections: (1) to pregnant dams on embryonic days 15-20; (2) to neonatal pups on days 0-5; or (3) to adults on days 55-60. At approximately 70 days of age, trunk blood was collected to determine corticosterone levels (1) upon removal from the home cage, (2) immediately after 30 min of restraint stress, or (3) 60 min after return to home cage following the stressor. Flutamide treatment resulted in higher basal levels of testosterone and stress levels of corticosterone compared to vehicle treatment, and there was no interaction of treatment with age at time of treatment. This suggests that testosterone is less effective at inhibiting HPA function in flutamide-treated males. In addition, prenatally treated males had higher stress levels of corticosterone than neonatally and adult-treated males, regardless of the type of treatment. There were no differences in CBG levels among the groups. The results suggest that, in males, flutamide treatment has a long-lasting effect on HPA function. These results are consistent with our previous research on neonatally gonadectomized males and the hypothesis of organizational effects of sex hormones on HPA function.

Economics, health-related quality of life, and cost-effectiveness methods for the TACTICS (Treat Angina With Aggrastat [tirofiban]] and Determine Cost of Therapy with Invasive or Conservative Strategy)-TIMI 18 trial

Concern over escalating health care costs has led to increasing focus on economics and assessment of outcome measures for expensive forms of therapy. This is being investigated in the Treat Angina With Aggrastat [tirofiban] and Determine Cost of Therapy with Invasive or Conservative Strategy (TACTICS)-TIMI 18 trial, a randomized trial comparing outcome of patients with unstable angina or non-Q-wave myocardial infarction treated with tirofiban and then randomized to an invasive versus a conservative strategy. Hospital and professional costs initially and over 6 months, including outpatient costs, will be assessed. Hospital costs will be determined for patients in the United States from the UB92 formulation of the hospital bill, with costs derived from charges using departmental cost to charge ratios. Professional costs will be determined by accounting for professional services and then converted to resource units using the Resource Based Relative Value Scale and then to costs using the Medicare conversion factor. Follow-up resource consumption, including medications, testing and office visits, will be carefully measured with a Patient Economic Form, and converted to costs from the Medicare fee schedule. Health-related quality of life will be assessed with a specific instrument, the Seattle Angina Questionnaire, and a general instrument, the Health Utilities Index at baseline, 1, and 6 months. The Health Utilities Index will also be used to construct a utility. By knowing utility and survival, quality-adjusted life years will be determined. These measures will permit the performance of a cost-effectiveness analysis, with the cost-effectiveness of the invasive strategy defined and the difference in cost between the invasive and conservative strategies divided by the difference in quality-adjusted life years. The economic and health-related quality of life aspects of TACTICS-TIMI 18 are an integral part of the study design and will provide a comprehensive understanding of the impact of invasive versus conservative management strategies on a broad range of outcomes after hospitalization for unstable angina or non-Q-wave myocardial infarction.

Are there clinical and laboratory predictors of 5-year mortality in HIV-infected children and adolescents with hemophilia?

To determine factors associated with survival in a cohort of HIV-infected children and adolescents with hemophilia, an analysis of the 5-year mortality data for 207 HIV-infected young men was performed to examine the effect of selected clinical covariates on survival. The subjects were enrolled into the Hemophilia Growth and Development Study cohort from 1989 to 1990. Estimated mean time since infection at baseline was 6.7 years and mean estimated age at infection was 6.5 years. The baseline characteristics examined for their association with the hazard of death over the 5-year follow-up period were the following: absolute CD4+ cell count, hemoglobin status, skin test anergy, results of brain magnetic resonance imaging, non-hemophilia-related muscle atrophy (NHRMA), height for age, and impaired neuropsychological functioning as measured by the Vineland Adaptive Behavior and the Pediatric Behavior Scales. In all, 66 deaths occurred over the 5-year follow-up, 62 of whom met the 1987 (n = 56) or 1993 (n = 6) U.S. Centers for Disease Control and Prevention (CDC) definition of AIDS. Although each of the characteristics listed previously significantly increased the hazard of death by Cox proportional hazard regression models, only NHRMA remained a significant predictor of AIDS-related death when added to models that included each of the other cited baseline covariates.

Satisfaction with practice in a rural state: perceptions of nurse practitioners and nurse midwives

Data from nurse practitioners and certified nurse midwives are used to explore contributions to primary care in a rural state and how regulatory restrictiveness and other factors affect satisfaction with practice (N = 151). Satisfaction is high, especially with home communities and professional aspects of work, including collaboration with physicians. However, many feel limited by regulations and are less satisfied, especially those with a master's degree and those in organizational versus office practice sites. Reducing restrictive regulations, reevaluating practice structures, and providing for full scope of practice and other incentives consistent with rising educational levels can increase access to care.

BW-755C diminishes smoke-induced pulmonary edema

Pulmonary edema following smoke inhalation is due to the chemical toxins in smoke and not to the heat. We have shown that acrolein, a common component of smoke, induces pulmonary edema, perhaps via release of leukotrienes. We, therefore, hypothesized that acrolein, a component of smoke from burning cotton, might have a major role in producing pulmonary edema in sheep after cotton smoke inhalation and that BW-755C, a combined cyclo- and lipoxygenase inhibitor, would prevent the edema, whereas indomethacin, a cyclooxygenase inhibitor, would not. In control anesthetized sheep (n = 7), 128 breaths of cotton smoke induced no change in pulmonary arterial pressure but induced increases (P < 0.05) in pulmonary lymph flow from 4.4 +/- 0.8 (SE) to 15 +/- 2.7 ml/h, lymph protein flux from 0.25 +/- 0.08 to 0.80 +/- 0.16 g/h, and blood-corrected wet-to-dry weight ratios from a normal value of 3.8 +/- 0.07 (n = 9) to 4.5 +/- 0.18. Indomethacin (n = 6) did not significantly prevent these changes, whereas BW-755C decreased lung lymph flow change from 5 +/- 1 to 7 +/- 2 ml/h (P = NS), lymph protein flux from 0.25 +/- 0.08 to 0.35 +/- 0.1 g/h (P = NS), and weight-to-dry ratio from normal to 3.9 +/- 2.1 (P = NS). These data suggest leukotrienes may have a role in producing cotton smoke-induced noncardiogenic pulmonary edema.

Breast cancer survival among women under age 50: is mammography detrimental?

Great uncertainty exists about the benefit of detecting breast cancer by mammography in women under 50 years of age. We have reviewed the survival of patients aged 49 years or less whose cancers were detected by mammography alone. 117 women under the age of 50 years were diagnosed with breast cancer between 1978 and 1991 based only on an abnormal mammogram. Ductal carcinoma in-situ (DCIS) was found in 47 (40%) of these women, whilst 70 (60%) had infiltrating ductal or infiltrating lobular carcinomas. During the same interval, 928 women in this age group presented with palpable breast cancer. DCIS was diagnosed in 82 (9%) of these women, whilst 846 (91%) had infiltrating carcinoma. Among the infiltrating cancers detected by mammography alone, 50% were stage I, whilst only 30% of the women with palpable cancers were stage I. Five-year survival for all mammographically detected cancer patients was 95%, whereas for women with palpable cancers the survival was 74% (p < 0.00005). If DCIS is not included, the corresponding survivals are 91% for mammographically detected infiltrating cancers and 72% for palpable infiltrating cancers. Only 1 woman who died among those with palpable cancer had had a mammogram before diagnosis. Our data contradict the suggestion that women under 50 are put at a survival disadvantage by undergoing mammography. We believe that investigators who have reported negative results in this age group must examine other causes for their results.

Calcified suture material in the breast after radiation therapy

Of 335 women who underwent lumpectomy and radiation therapy for breast cancer, 42 subsequently developed calcifications. Particles typical of calcified suture material were identified in 21 of the 42 women (50%). No obvious calcified suture material was found in approximately 1,140 women of 38,000 (3%) who had undergone mammography after they had previously undergone breast biopsy for a benign lesion and thus had not undergone radiation therapy. Calcified suture material rarely develops in the nonirradiated breast, but it is common after radiation therapy and should not be confused with recurrent breast cancer. These calcifications are likely the result of delayed resorption of catgut sutures, which provide a matrix on which calcium can precipitate in a suitable local environment.