Survival from Rhino-Orbital-Cerebral Mucormycosis in SARS-CoV-2-Positive Diabetic Patients: Two Case Reports

Introduction

Rhino-orbital-cerebral mucormycosis (ROCM) is a rare angioinvasive fungal infection known to be associated with high morbidity and over 50% mortality. ROCM is becoming more common due to an increase in predisposing immunocompromising comorbidities as well as COVID-19.

Case Presentations

We report 2 cases - a 75-year-old woman with diabetes and a 39-year-old man with recurrent diabetic ketoacidosis. Both presented initially with acute sinonasal symptoms, were positive for SARS-CoV-2, and diagnosed with acute ROCM. Both underwent mutilating surgical therapy as well as high-dose amphotericin B treatment. With continued oral antifungal treatment, patient 1 showed stable symptoms despite radiographically increasing disease and died of urosepsis 5 months after first surgery. With posaconazole treatment, patient 2 recovered from the disease and showed no clinical sign of disease progression after 1 year.

Conclusion

Despite the rarity of the disease, ROCM should be considered if the findings of clinical and radiological examination fit, so that a delay in treatment initiation can be avoided. As our both cases show, survival from ROCM is possible - albeit at a high cost.

In Situ Measurement of Electron Energy Evolution in a Laser-Plasma Accelerator

We report on a novel, noninvasive method applying Thomson scattering to measure the evolution of the electron beam energy inside a laser-plasma accelerator with high spatial resolution. The determination of the local electron energy enabled the in-situ detection of the acting acceleration fields without altering the final beam state. In this Letter we demonstrate that the accelerating fields evolve from (265±119)  GV/m to (9±4)  GV/m in a plasma density ramp. The presented data show excellent agreement with particle-in-cell simulations. This method provides new possibilities for detecting the dynamics of plasma-based accelerators and their optimization.

Compact all-optical precision-tunable narrowband hard Compton X-ray source

Readily available bright X-ray beams with narrow bandwidth and tunable energy promise to unlock novel developments in a wide range of applications. Among emerging alternatives to large-scale and costly present-day radiation sources which severely restrict the availability of such beams, compact laser-plasma-accelerator-driven inverse Compton scattering sources show great potential. However, these sources are currently limited to tens of percent bandwidths, unacceptably large for many applications. Here, we show conceptually that using active plasma lenses to tailor the electron bunch-photon interaction, tunable X-ray and gamma beams with percent-level bandwidths can be produced. The central X-ray energy is tunable by varying the focusing strength of the lens, without changing electron bunch properties, allowing for precision-tuning the X-ray beam energy. This method is a key development towards laser-plasma-accelerator-driven narrowband, precision tunable femtosecond photon sources, enabling a paradigm shift and proliferation of compact X-ray applications.

Combining laser interferometry and plasma spectroscopy for spatially resolved high-sensitivity plasma density measurements in discharge capillaries

Precise characterization and tailoring of the spatial and temporal evolution of plasma density within plasma sources are critical for realizing high-quality accelerated beams in plasma wakefield accelerators. The simultaneous use of two independent diagnostics allowed the temporally and spatially resolved detection of plasma density with unprecedented sensitivity and enabled the characterization of the plasma temperature in discharge capillaries for times later than 0.5 µs after the initiation of the discharge, at which point the plasma is at local thermodynamic equilibrium. A common-path two-color laser interferometer for obtaining the average plasma density with a sensitivity of 2 × 10¹⁵ cm^-2 was developed together with a plasma emission spectrometer for analyzing spectral line broadening profiles with a resolution of 5 × 10¹⁵ cm^-3. Both diagnostics show good agreement when applying the spectral line broadening analysis methodology of Gigosos and Cardeñoso in the temperature range of 0.5 eV-5.0 eV. For plasma with densities of 0.5-2.5 × 10¹⁷ cm^-3, temperatures of 1 eV-7 eV were indirectly measured by combining the diagnostic information. Measured longitudinally resolved plasma density profiles exhibit a clear temporal evolution from an initial flat-top to a Gaussian-like shape in the first microseconds as material is ejected out from the capillary. These measurements pave the way for highly detailed parameter tuning in plasma sources for particle accelerators and beam optics.

Impaired Isometric Force Matching in Upper and Lower Limbs Revealed by Quantitative Motor Assessments in Huntington's Disease

BACKGROUND

Assessment of motor symptoms in Huntington's disease (HD) is based on the Unified-HD-Rating-Scale-Total-Motor-Score (UHDRS-TMS). Its categorical and rater-dependent nature reduces the ability to detect subtle changes and often placebo effects have been observed in trials. We have previously shown that impairments in isometric force matching can be detected by quantitative motor (Q-Motor) assessments of tongue protrusion forces (glossomotography) in HD.

OBJECTIVE

We aimed to investigate whether similar impairments in isometric force matching can be detected in tasks assessing hand and foot force coordination and whether correlations with clinical measures and the disease burden score can be found.

METHODS

Using a pre-calibrated force transducer, the ability of subjects to generate and maintain isometric forces at different target levels displayed on a monitor was assessed. Target forces applied in the hand were 1.5 and 5 Newton [N] and in feet 1, 5, and 10 N. Subjects with HD (n = 31) and age-matched controls (n = 22) were recruited from the HD out-patient clinic.

RESULTS

All paradigms distinguished controls from HD. The static coefficient of variability (%) was the most robust measure across all matching tasks. Correlations with clinical measures, such as the UHDRS-TMS, TFC, and the DBS were found.

CONCLUSIONS

Assessment of hand and foot force matching tasks was feasible and provided quantitative objective measures for severity of motor phenotype in HD. Since both upper and lower extremity motor function are relevant for everyday activities, these measures should be further assessed as candidates for developing functionally meaningful quantitative motor tasks.

Gait variability as digital biomarker of disease severity in Huntington's disease

BACKGROUND

Impaired gait plays an important role for quality of life in patients with Huntington's disease (HD). Measuring objective gait parameters in HD might provide an unbiased assessment of motor deficits in order to determine potential beneficial effects of future treatments.

OBJECTIVE

To objectively identify characteristic features of gait in HD patients using sensor-based gait analysis. Particularly, gait parameters were correlated to the Unified Huntington's Disease Rating Scale, total motor score (TMS), and total functional capacity (TFC).

METHODS

Patients with manifest HD at two German sites (n = 43) were included and clinically assessed during their annual ENROLL-HD visit. In addition, patients with HD and a cohort of age- and gender-matched controls performed a defined gait test (4 × 10 m walk). Gait patterns were recorded by inertial sensors attached to both shoes. Machine learning algorithms were applied to calculate spatio-temporal gait parameters and gait variability expressed as coefficient of variance (CV).

RESULTS

Stride length (- 15%) and gait velocity (- 19%) were reduced, while stride (+ 7%) and stance time (+ 2%) were increased in patients with HD. However, parameters reflecting gait variability were substantially altered in HD patients (+ 17% stride length CV up to + 41% stride time CV with largest effect size) and showed strong correlations to TMS and TFC (0.416 ≤ r_Sp ≤ 0.690). Objective gait variability parameters correlated with disease stage based upon TFC.

CONCLUSIONS

Sensor-based gait variability parameters were identified as clinically most relevant digital biomarker for gait impairment in HD. Altered gait variability represents characteristic irregularity of gait in HD and reflects disease severity.

FLASHForward: plasma wakefield accelerator science for high-average-power applications

The FLASHForward experimental facility is a high-performance test-bed for precision plasma wakefield research, aiming to accelerate high-quality electron beams to GeV-levels in a few centimetres of ionized gas. The plasma is created by ionizing gas in a gas cell either by a high-voltage discharge or a high-intensity laser pulse. The electrons to be accelerated will either be injected internally from the plasma background or externally from the FLASH superconducting RF front end. In both cases, the wakefield will be driven by electron beams provided by the FLASH gun and linac modules operating with a 10 Hz macro-pulse structure, generating 1.25 GeV, 1 nC electron bunches at up to 3 MHz micro-pulse repetition rates. At full capacity, this FLASH bunch-train structure corresponds to 30 kW of average power, orders of magnitude higher than drivers available to other state-of-the-art LWFA and PWFA experiments. This high-power functionality means FLASHForward is the only plasma wakefield facility in the world with the immediate capability to develop, explore and benchmark high-average-power plasma wakefield research essential for next-generation facilities. The operational parameters and technical highlights of the experiment are discussed, as well as the scientific goals and high-average-power outlook. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.

Tunable Plasma-Based Energy Dechirper

A tunable plasma-based energy dechirper has been developed at FLASHForward to remove the correlated energy spread of a 681 MeV electron bunch. Through the interaction of the bunch with wakefields excited in plasma the projected energy spread was reduced from a FWHM of 1.31% to 0.33% without reducing the stability of the incoming beam. The experimental results for variable plasma density are in good agreement with analytic predictions and three-dimensional simulations. The proof-of-principle dechirping strength of 1.8  GeV/mm/m significantly exceeds those demonstrated for competing state-of-the-art techniques and may be key to future plasma wakefield-based free-electron lasers and high energy physics facilities, where large intrinsic chirps need to be removed.

Objective assessment of gait and posture in premanifest and manifest Huntington disease - A multi-center study

BACKGROUND

Deficits in posture and gait are known to contribute to the complex motor phenotype of Huntington disease (HD). Objective and quantitative measures of posture and gait provided by posturography and GAITRite^® assessments may supplement categorical rating scales such as the UHDRS-TMS and increase power and sensitivity of clinical trials.

OBJECTIVES

To investigate whether posturography and GAITRite^® measures reveal (1) changes in manifest or premanifest HD mutation-carriers, (2) a correlation to the UHDRS-TMS and functional measures in manifest HD, and (3) a correlation to the disease-burden-score (based on CAG-repeat-length and age).

METHODS

Posturography and GAITRite^® were applied in premanifest (n = 26) and manifest HD gene-mutation-carriers (n = 40) in different paradigms compared to age-matched controls (n = 30) in a cross-sectional multi-site study conducted in three centers. Subjects were assessed clinically with the UHDRS Total-Motor-Score, Total-Functional-Capacity and Functional-Assessment-Scale.

RESULTS

Several posturography measures were able to discriminate between controls, premanifest, and manifest mutation-carriers in both conditions assessed. Only one GAITRite^® measure separated controls and premanifest participants, while discrimination between controls and manifest same as between premanifest and manifest participants was possible in several measures. Correlation with all clinical measures was seen in only one measure per device while correlations to the disease-burden-score seen in posturography only.

CONCLUSION

Overall the results suggests that posturography detects alterations in premanifest and manifest mutation-carriers more reliably than GAITRite^® measures. Correlations with clinical assessment scores are limited; correlation with disease-burden-score is seen in posturography only. Data acquisition and analysis was easier with posturography than GAITRite^® assessments in out-patient settings.

A longitudinal study of magnetic resonance spectroscopy Huntington's disease biomarkers

Putaminal metabolites examined using cross-sectional magnetic resonance spectroscopy (MRS) can distinguish pre-manifest and early Huntington's Disease (HD) individuals from controls. An ideal biomarker, however, will demonstrate longitudinal change over short durations. The objective here was to evaluate longitudinal in vivo brain metabolite profiles in HD over 24 months. Eighty-four participants (30 controls, 25 pre-manifest HD, 29 early HD) recruited as part of TRACK-HD were imaged at baseline, 12 months, and 24 months using 3T MRS of left putamen. Automated putaminal volume measurement was performed simultaneously. To quantify partial volume effects, spectroscopy was performed in a second, white matter voxel adjacent to putamen in six subjects. Subjects underwent TRACK-HD motor assessment. Statistical analyses included linear regression and one-way analysis of variance (ANOVA). At all time-points N-acetyl aspartate and total N-acetyl aspartate (NAA), neuronal integrity markers, were lower in early HD than in controls. Total NAA was lower in pre-manifest HD than in controls, whereas the gliosis marker myo-inositol (MI) was robustly elevated in early HD. Metabolites were stable over 24 months with no longitudinal change. Total NAA was not markedly different in adjacent white matter than putamen, arguing against partial volume confounding effects in cross-sectional group differences. Total NAA correlations with disease burden score suggest that this metabolite may be useful in identifying neurochemical responses to therapeutic agents. We demonstrate almost consistent group differences in putaminal metabolites in HD-affected individuals compared with controls over 24 months. Future work establishing spectroscopy as an HD biomarker should include multi-site assessments in large, pathologically diverse cohorts.

FDG μPET Fails to Detect a Disease-Specific Phenotype in Rats Transgenic for Huntington's Disease – A 15 Months Follow-up Study

BACKGROUND

FDG-PET detects hypometabolism in premanifest and symptomatic Huntington's disease (HD). A cross-sectional study suggested that whole-brain FDG-PET is capable to detect a phenotype in transgenic (tg) HD rats. Recently, a longitudinal follow-up study showed no FDG-PET changes in tgHD rats. Both studies applied small sample sizes and analysis was limited to whole-brain or striatum.

OBJECTIVE

We therefore performed a follow-up study in a larger cohort of tgHD and wild-type (wt) rats encompassing several pre-defined regions of interest (ROIs) and hypothesis free voxel-by-voxel SPM analysis to clarify whether FDG-PET can detect a phenotype in tgHD rats and to determine onset …and effect sizes of changes over time.

METHODS

N = 19 tgHD- and n = 20 wt-rats, mixed gender, were included. Repeated small animal FDG-μPET and MRI were performed at 5,10,15, and 20 months of age. ROIs encompassing entire brain, cortex, striatum, thalamus, subventricular-zone, and cerebellum were placed manually on the MRI and transferred to the co-registered μPET. Mean and maximal FDG-PET activities within ROIs were calculated and normalized to cerebellar FDG uptake. Activity and spatially normalized FDG-μPET were compared between groups on a hypothesis-free voxel-by-voxel basis using SPM.

RESULTS

FDG uptake showed changes over time in both tgHD- and wt-rats, however, there was no consistent difference between tgHD- and wt-rats in both the manual ROI and SPM analysis.

CONCLUSIONS

In this transgenic rat model of HD FDG-μPET imaging does not detect significant alterations at the ages investigated. Further investigations are warranted employing other age groups and alternative imaging biomarkers for neuronal degeneration, respectively.