A natural history study to track brain and spinal cord changes in individuals with Friedreich's ataxia: TRACK-FA study protocol

INTRODUCTION

Drug development for neurodegenerative diseases such as Friedreich's ataxia (FRDA) is limited by a lack of validated, sensitive biomarkers of pharmacodynamic response in affected tissue and disease progression. Studies employing neuroimaging measures to track FRDA have thus far been limited by their small sample sizes and limited follow up. TRACK-FA, a longitudinal, multi-site, and multi-modal neuroimaging natural history study, aims to address these shortcomings by enabling better understanding of underlying pathology and identifying sensitive, clinical trial ready, neuroimaging biomarkers for FRDA.

METHODS

200 individuals with FRDA and 104 control participants will be recruited across seven international study sites. Inclusion criteria for participants with genetically confirmed FRDA involves, age of disease onset ≤ 25 years, Friedreich's Ataxia Rating Scale (FARS) functional staging score of ≤ 5, and a total modified FARS (mFARS) score of ≤ 65 upon enrolment. The control cohort is matched to the FRDA cohort for age, sex, handedness, and years of education. Participants will be evaluated at three study visits over two years. Each visit comprises of a harmonized multimodal Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) scan of the brain and spinal cord; clinical, cognitive, mood and speech assessments and collection of a blood sample. Primary outcome measures, informed by previous neuroimaging studies, include measures of: spinal cord and brain morphometry, spinal cord and brain microstructure (measured using diffusion MRI), brain iron accumulation (using Quantitative Susceptibility Mapping) and spinal cord biochemistry (using MRS). Secondary and exploratory outcome measures include clinical, cognitive assessments and blood biomarkers.

DISCUSSION

Prioritising immediate areas of need, TRACK-FA aims to deliver a set of sensitive, clinical trial-ready neuroimaging biomarkers to accelerate drug discovery efforts and better understand disease trajectory. Once validated, these potential pharmacodynamic biomarkers can be used to measure the efficacy of new therapeutics in forestalling disease progression.

CLINICAL TRIAL REGISTRATION

ClinicalTrails.gov Identifier: NCT04349514.

Early molecular imaging of interstitial changes in patients after myocardial infarction: comparison with delayed contrast-enhanced magnetic resonance imaging

INTRODUCTION

The clinical feasibility of noninvasive imaging of interstitial alterations after myocardial infarction (MI) was assessed using a technetium-99m-labeled RGD imaging peptide (RIP). In experimental studies, RIP has been shown to target integrins associated with collagen-producing myofibroblasts (MFB).

METHODS AND RESULTS

Ten patients underwent myocardial perfusion imaging (MPI) within the first week after MI. At 3 and 8 weeks after MI, RIP was administered intravenously and SPECT images acquired for interstitial imaging. RIP imaging was compared to initial MPI and to the extent of scar formation defined by late gadolinium-enhanced (LGE) cardiac magnetic resonance (CMR) imaging 1 year after MI. RIP uptake was observed in 7 of the 10 patients at both 3 and 8 weeks. Although, RIP uptake corresponded to areas of perfusion defects, it usually extended beyond the infarct zone to a variable extent; 2 of 7 patients showed tracer uptake throughout myocardium. In all positive cases, RIP uptake was similar to the extent of scar observed at 1 year by LGE-CMR imaging.

CONCLUSION

This study demonstrates that RGD-based imaging early after MI may predict the eventual extent of scar formation, which often exceeds initial MPI deficit but colocalizes with LGE in CMR imaging performed subsequently.

Biopsy Confirmation of Metastatic Disease in Breast Cancer: Results from a Large Prospective Study

Purpose: Decisions about systemic treatment of women with metastatic breast cancer are often based on estrogen receptor (ER), progesterone receptor (PgR), and HER2/neu status of the primary tumour. This study prospectively investigated concordance in receptor status between primary tumour and distant metastases at various stages of progression and assessed the impact of any discordance on patient management.Methods: Biopsies of suspected metastatic lesions were obtained from patients and analyzed for ER/PgR and HER2/neu. Receptor status of metastases was compared to the primary tumour. The treating physician completed questionnaires before and after biopsy to determine whether the biopsy result lead to a change in treatment plan.Results: One hundred and sixteen women were enrolled and 102 underwent biopsy. Of these 52 (51%) were newly diagnosed with metastatic disease, 17 (17%) had received one line of metastatic treatment and 35 (34%) had received 2 or more lines of treatment in the metastatic setting. 86/102 (84%) of samples were sufficient analysis; of these 5/86 biopsies (6%) showed benign disease and one biopsy (1%) confirmed a different malignancy (indolent lymphoma). Changes in hormone receptor status were observed in 33%. Among these, ER discordance was seen in 11%, PgR discordance in 27% and discordance in both ER and PgR in 5%. Loss of PgR was the most common change in hormone receptor status (25%). HER2/neu showed 4% discordance. Three patients (3%) gained and one patient (1%) lost HER2/neu expression. Biopsy results led to a change of management in 12% of patients. Patients with newly diagnosed metastatic disease were more likely to show discordance than those previously treated in the metastatic setting. Among triple negative primary tumours, no changes in receptor expression of metastases were seen.Conclusions: This is the largest prospective biopsy study we are aware of. Results demonstrate the presence of substantial discordance in receptor status between primary tumour and metastases. The number needed to biopsy to alter immediate management was 8.5, although biopsy information could also be useful in planning subsequent treatments. Tissue confirmation should therefore, be considered in all patients with suspicion of metastatic recurrence or progression.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2023.

The fetish of the objective finding

Pressure is mounting for clinicians to rely solely on objective measures when evaluating workers with possible work-related disease. These measures are intended to largely supplant the worker's history as sources of information regarding diagnosis, work relatedness, and extent of disability. While seeming to promote more accurate and neutral evaluation methods, the underlying agenda is to reduce business costs by denying work-related illness and disability. Promoting the view of occupational health as the province of technical experts, the campaign for the objective finding silences workers as unqualified to comment. The methods proposed to enhance objectivity also suffer from significant specific shortcomings. To resist efforts to fetishize the objective finding, clinicians need to recognize the subjective elements of objective methods as well as the objective value of subjective data. This requires recognition of the central role of workers and histories in the clinical evaluation process.

Anomalous diffraction of light with geometrical path statistics of rays and a Gaussian ray approximation

The anomalous-diffraction theory (ADT) of extinction of light by soft particles is shown to be determined by a statistical distribution of the geometrical paths of individual rays inside the particles. Light extinction depends on the mean and the mean-squared geometrical paths of the rays. Analytical formulas for optical efficiencies from a Gaussian distribution of the geometrical paths of rays are derived. This Gaussian ray approximation reduces to the exact ADT in the intermediate case of light scattering for an arbitrary soft particle and describes well the extinction of light from a system of randomly oriented and (or) polydisperse particles. The implications for probing of the sizes and shapes of particles by light extinction are discussed.

Photon migration in turbid media using a cumulant approximation to radiative transfer

A photon transport model for light migration in turbid media based on a cumulant approximation to radiative transfer is presented for image reconstruction inside an infinite medium or a bounded medium with a planar geometry. This model treats weak inhomogeneities through a Born approximation of the Boltzmann radiative transfer equation and uses the second-order cumulant solution of photon density to the Boltzmann equation as the Green's function for the uniform background. It provides the correct behavior of photon migration at early times and reduces at long times to the center-moved diffusion approximation. At early times, it agrees much better with the result from the Monte Carlo simulation than the diffusion approximation. Both approximations agree well with the Monte Carlo simulation at later times. The weight function for image reconstruction under this proposed model is shown to have a strong dependence at both early and later times on absorption and/or scattering inhomogeneities located in the propagation direction of and close to the source, or in the field of view of and close to the detector. This effect originates from the initial ballistic motion of incident photons, which is substantially underestimated by the diffusion approximation.

Photon-transport forward model for imaging in turbid media

A photon-transport forward model for image reconstruction in turbid media is derived that treats weak inhomogeneities through a Born approximation of the Boltzmann radiative transfer equation. This model can conveniently replace the commonly used diffusion approximation in optical tomography. An analytical expression of the background Green's function is obtained from the cumulant solution of the Boltzmann equation. Our model provides the correct behavior of photon migration at early times and reduces at long times to the center-moved diffusion approximation. Numerical comparisons between this model and the standard and center-moved diffusion models are presented.

Clinical and imaging correlates of response to treatment with infliximab in patients with ankylosing spondylitis

OBJECTIVES

Ankylosing spondylitis (AS) is a chronic disease leading to progressive spinal ankylosis and deformity. The aims of this study were to (1) determine whether infliximab is an effective treatment for AS patients who have failed conventional treatment; (2) identify any baseline clinical variables that can be associated with responsiveness to treatment; and (3) resolve whether the clinical response correlated with changes from baseline inflammatory changes on magnetic resonance imaging (MRI).

METHODS

Twenty-one patients who met the modified New York criteria for AS (M:F 18:3) were enrolled in this open labeled study. The mean age was 37.9+/-7.9 years and mean disease duration was 8.69+/-6.58 years. Patients received infliximab at a dose of 5 mg/kg by intravenous infusion over 2 hours at 0, 2, 6, weeks. Nine functional variables were measured [i.e., Bath AS Disease Activity Index (BASDAI), Bath AS Functional Index (BASFI) etc.], 6 clinimetrics (chest expansion, finger to floor, etc.), and inflammatory markers in the peripheral blood at baseline and each subsequent visit. Primary response to treatment was defined as a > 20% response in 5/9 functional variables. A subset of 9 consecutive patients was selected for MRI scans before and after infusions.

RESULTS

Eighteen patients were available for assessment at week 14 having received 3 infusions (wks 0, 2, 6). There was > 60% improvement in functional variables, i.e., BASDAI, BASFI, Health Assessment Questionnaire, fatigue, and spinal and total body pain. Clinimetric scores selectively improved, e.g., chest expansion (p < 0.021) by 14 weeks. ESR, CRP and haptoglobin all showed significant improvement at 6 weeks and were maintained to the 14 week assessment point. Imaging studies showed improvement in all patients studied including those with advanced disease. Three patients developed headache during the infusions. Infliximab was effective in all, but degree of response varied. Very good responders were distinguished from good responders by shorter duration of disease and better baseline clinimetric scores.

CONCLUSIONS

Infliximab was an effective treatment for AS in a short term trial. Longterm control of symptoms and potential alteration in clinical course of disease will require longterm assessment.

Time-resolved Fourier optical diffuse tomography

Time-resolved Fourier optical diffuse tomography is a novel approach for imaging of objects in a highly scattering turbid medium with use of an incident (near) plane wave. The theory of the propagation of spatial Fourier components of the scattered wave field is presented, along with a fast algorithm for three-dimensional reconstruction in a parallel planar geometry. Examples of successful reconstructions of simulated hidden absorptive or scattering objects embedded inside a human-tissue-like semi-infinite turbid medium are provided.

Analytical solution of the polarized photon transport equation in an infinite uniform medium using cumulant expansion

An analytical solution for time-dependent polarized photon transport equation in an infinite uniform isotropic medium is studied using a circular representation of the polarized light and expansion in the generalized spherical functions. We extend our cumulant approach for solving the scalar (unpolarized) photon transport equation to the vector (polarized) case. As before, an exact angular distribution is obtained and a cumulant expansion is derived for the polarized photon distribution function. By a cutoff at the second cumulant order, a Gaussian analytical approximate expression of the polarized photon spatial distribution is obtained as a function of the direction of light and time, whose average center position and half-width are always exact. The central limit theorem claims that this spatial distribution approaches accuracy in detail when the number of collisions or time becomes large. The analytical expression of cumulants up to an arbitrary high order is also derived, which can be used for calculating a more accurate polarized photon distribution through a numerical Fourier transform. Contrary to what occurs in other approximation techniques, truncation of the cumulant expansion at order n is exact at that order and cumulants up to and including order n remain unchanged when higher orders are added, at least as applied in our photon transport equation.

Cumulant solution of the elastic boltzmann transport equation in an infinite uniform medium

We consider an analytical solution of the time-dependent elastic Boltzmann transport equation in an infinite uniform isotropic medium with an arbitrary phase function. We obtain (1) the exact distribution in angle, (2) the exact first and second spatial cumulants at any angle, and (3) an approximate combined distribution in position and angle and a spatial distribution whose central position and half-width of spread are always exact. The resulting Gaussian distribution has a center that advances in time, and an ellipsoidal contour that grows and changes shape providing a clear picture of the time evolution of the particle migration from near ballistic, through snakelike and into the final diffusive regime.

Optical tomographic image reconstruction from ultrafast time-sliced transmission measurements

Optical imaging and localization of objects inside a highly scattering medium, such as a tumor in the breast, is a challenging problem with many practical applications. Conventional imaging methods generally provide only two-dimensional (2-D) images of limited spatial resolution with little diagnostic ability. Here we present an inversion algorithm that uses time-resolved transillumination measurements in the form of a sequence of picosecond-duration intensity patterns of transmitted ultrashort light pulses to reconstruct three-dimensional (3-D) images of an absorbing object located inside a slab of a highly scattering medium. The experimental arrangement used a 3-mm-diameter collimated beam of 800-nm, 150-fs, 1-kHz repetition rate light pulses from a Ti:sapphire laser and amplifier system to illuminate one side of the slab sample. An ultrafast gated intensified camera system that provides a minimum FWHM gate width of 80 ps recorded the 2-D intensity patterns of the light transmitted through the opposite side of the slab. The gate position was varied in steps of 100 ps over a 5-ns range to obtain a sequence of 2-D transmitted light intensity patterns of both less-scattered and multiple-scattered light for image reconstruction. The inversion algorithm is based on the diffusion approximation of the radiative transfer theory for photon transport in a turbid medium. It uses a Green s function perturbative approach under the Rytov approximation and combines a 2-D matrix inversion with a one-dimensional Fourier-transform inversion to achieve speedy 3-D image reconstruction. In addition to the lateral position, the method provides information about the axial position of the object as well, whereas the 2-D reconstruction methods yield only lateral position.

Time-resolved optical backscattering model in highly scattering media

A time-resolved backscattering model, which combines a single large-angle scattering with multiple small-angle scatterings, is used to produce a scattered-light profile about a medium. Inhomogeneity of the medium is included in the model. Some multidimensional integrals can be evaluated analytically.

Relationship between prenatal anxiety and perinatal outcome in nulliparous women: a prospective study

Nulliparous women with singleton gestation were assessed prospectively for anxiety levels with the State-Trait Anxiety Inventory, which measured state (situational and transitional) and trait (dispositional and stable) anxiety, with high scores indicating high anxiety. Bivariate and multivariate methods were used for data analysis. Anxiety assessments (n = 239) were obtained in 88 women at different stages of gestation. Mean anxiety scores were lowest at 22 to 26 weeks. A woman's successive scores were highly correlated. The trait anxiety (A-T) scores were higher for married women. A positive correlation was present between anxiety scores and gestational age at delivery. Low A-T scores correlated with low birthweight, preterm delivery, and chorioamnionitis. High state anxiety (A-S) levels correlated with the presence of meconium in the amniotic fluid and neonatal congenital abnormalities. Postdate delivery also was associated with higher although statistically insignificant anxiety scores. Women who presented to the labor and delivery room for various complaints had higher A-S and A-T levels. Maternal anxiety level was associated with adverse perinatal outcome; specifically, prematurity and low birthweight correlated with low A-T levels.

Time-resolved optical diffusion tomographic image reconstruction in highly scattering turbid media

The image of an object hidden in highly scattering media was reconstructed using a fast, noise-resistant algorithm newly applied to diffusion tomography. A pulsed light source producing scattered and transmitted light is examined at multiple times. Multiple source detector pairs around the medium are used to obtain data in many different directions. An inverse scattering algorithm with nonuniform regularization achieves rapid inversion convergence.

Health hazard of poorly regulated exposure during manufacture of cemented tungsten carbides and cobalt

Forty two of 125 former workers in a factory in Syracuse, New York, which manufactured hard metal parts from tungsten carbide and cobalt, were studied by chest radiographs, spirometry, and plethysmographically determined lung volumes. The plant was closed in 1982 and the studies were performed in 1983-5. Recorded measurements of carbide dust concentrations were only mildly excessive by modern standards, but deceitful efforts to reduce the apparent concentration of dust were known to have occurred during an inspection by the Occupational Safety and Health Administration. Lung biopsies in four cases in the study and necropsy in one of the 83 cases not studied during life showed giant cell interstitial pneumonia and appreciable concentrations of tungsten carbide. This information indicates that exposure was substantial. Four workers had evidence of pulmonary fibrosis by chest radiographs; two of these workers had normal pulmonary function. Fourteen had abnormal pulmonary function, five of whom had a restrictive pattern, eight a pattern of air trapping, and one a combined pattern. Thus radiographic, or functional abnormalities, or both occurred in 16 of the 42 cases studied. No correlation with duration of exposure was established. Progressive clinically important disease (one fatal) has been found in four ex-workers, two in each of the restrictive and air trapping groups. These findings suggest that poorly regulated dust concentrations in a hard metals factory possibly cause pulmonary abnormalities and sometimes severe illness.

Stability of 7-alkyldeoxyguanosines of trichloropropylene oxide, epichlorohydrin and glycidol

Deoxyguanosine was reacted with trichloropropylene oxide (TCPO), epichlorohydrin and glycidol in aqueous solution and the products were isolated by high pressure liquid chromatography (HPLC). For each compound 7-alkyldeoxyguanosine was the main adduct; TPCO reacted about 3 times faster than epichlorohydrin and about 10 times faster than glycidol. The pKa's of the 7-alkyldeoxyguanosines were 6.7, 6.8 and 6.9 for the TCPO-, epichlorohydrin-, and glycidol-adducts, respectively. The respective half-lives of imidazole ring-opening were 6.3, 15 and 27 hrs (pH 8.5, 28 degrees) and those of depurination 1.9, 3.4 and 4.4 hrs (pH 5.5, 28 degrees).

End correction in the quasi-fast Hankel transform for optical propagation problems

An explicit evaluation is made of a simple end correction to the quasi-fast Hankel-transform algorithm. Application to a Gaussian beam shows that for a given accuracy, the use of this end correction permits a reduction of a factor of 8 in storage as well as a factor of 8 in running time.

Continuous Fourier-transform spline solution of unstable resonator-field distribution

To deal with sharply cut off fields at mirror edges, a continuous Fourier integration procedure is described. A spline fit is made to the discrete data, followed by analytic integration of the spline functions. End corrections associated with the difference between spline functions near the edges and the remaining uniform splines are made. This procedure permits an accurate integration of the paraxial equation in the thin-gain-sheet approximation.