Laterality of deep white matter hyperintensities correlates with basilar artery bending and vertebral artery dominance

Aim To investigate whether vertebrobasilar geometry contributes to the presence, severity, and laterality of white matter hyperintensities (WMH). Methods We retrospectively reviewed 290 cerebral scans of patients who underwent time-of-flight and fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) between 2017 and 2018. WMH were counted, localized, and grouped according to laterality on the FLAIR sequence. A 3D mesh of the posterior circulation was reconstructed (with ITK SNAP software) and the morphology of the vertebrobasilar system analyzed with an in-house software written in Python. Results Patients were assigned into a group with WMH (n=204) and a group without WMH (n=86). The severity of WMH burden was mainly affected by age and hypertension, while the localization of the WMH (or laterality) was mainly affected by the vertebrobasilar system morphology. Basilar artery morphology only affected the parietooccipital region significantly if both posterior communicating arteries were hypoplastic or absent. The dominant vertebral artery and basilar artery curve had an opposite directional relationship. Conclusions An unequal vertebral artery flow is an important hemodynamic contributor to basilar bending. Increased basilar artery curvature and increased infratentorial WMH burden may signal inadequate blood flow and predict cerebrovascular events

A clinical feasibility study to evaluate the safety and efficacy of PEOT/PBT implants for human donor site filling during mosaicplasty

Mosaicplasty has become a well-accepted treatment modality for articular cartilage lesions in the knee. Postoperative bleeding remains potentially concerning. This study evaluates the porous poly(ethylene oxide)terephthalate/poly(butylene terephthalate) (PEOT/PBT) implants used for donor site filling. Empty donor sites were the controls. After 9 months, MRI, macroscopical and histological analysis were carried out. Treated defects did not cause postoperative bleeding. No adverse events or inflammatory response was observed. PEOT/PBT implants were well integrated. Empty controls occasionally showed protrusion of repair tissue at the defect margins. Surface stiffness was minimally improved compared to controls. Existing polymer fragments indicated considerable biodegradation. Histological evaluation of the filled donor sites revealed congruent fibrocartilaginous surface repair with proteoglycan-rich domains and subchondral cancellous bone formation with interspersed fibrous tissue in all implanted sites. The PEOT/PBT implants successfully reduce donor site morbidity and postoperative bleeding after mosaicplasty

Acute severe thrombocytopenia following non-ionic low-osmolarity intravenous contrast medium injection

Intravenous contrast medium (ICM) rarely induces anaphylactic reactions, including urticaria, hypotension and respiratory failure. Even the most modern ICM may cause such adverse events. Thrombocytopenia has been reported as an extreme rare consequence of ICM. Here we report on a case of a 72-year-old male patient with a self-limiting severe acute thrombocytopenia following administration of intravenous non-ionic low-osmolarity contrast medium. No such low platelet count has ever been reported. We also present a review of the literature. Copyright © 2012 The Korean Society of Radiology

The chromatin-modifying protein HUB2 is involved in the regulation of lignin composition in xylem vessels

PIRIN2 (PRN2) was earlier reported to suppress syringyl (S)-type lignin accumulation of xylem vessels of Arabidopsis thaliana. In the present study, we report yeast two-hybrid results supporting the interaction of PRN2 with HISTONE MONOUBIQUITINATION2 (HUB2) in Arabidopsis. HUB2 has been previously implicated in several plant developmental processes, but not in lignification. Interaction between PRN2 and HUB2 was verified by β-galactosidase enzymatic and co-immunoprecipitation assays. HUB2 promoted the deposition of S-type lignin in the secondary cell walls of both stem and hypocotyl tissues, as analysed by pyrolysis-GC/MS. Chemical fingerprinting of individual xylem vessel cell walls by Raman and Fourier transform infrared microspectroscopy supported the function of HUB2 in lignin deposition. These results, together with a genetic analysis of the hub2 prn2 double mutant, support the antagonistic function of PRN2 and HUB2 in deposition of S-type lignin. Transcriptome analyses indicated the opposite regulation of the S-type lignin biosynthetic gene FERULATE-5-HYDROXYLASE1 by PRN2 and HUB2 as the underlying mechanism. PRN2 and HUB2 promoter activities co-localized in cells neighbouring the xylem vessel elements, suggesting that the S-type lignin-promoting function of HUB2 is antagonized by PRN2 for the benefit of the guaiacyl (G)-type lignin enrichment of the neighbouring xylem vessel elements

Case Report: Brainstem angiocentric glioma presenting in a toddler child–diagnostic and therapeutic challenges

Introduction: Angiocentric gliomas (AG) in brainstem location are exceedingly rare and might cause differential diagnostic problems and uncertainty regarding the best therapeutic approach. Hereby, we describe the clinicopathological findings in a brainstem AG presenting in a toddler child and review the literature.Case report: A 2-year-old boy presented with 5 weeks history of gait disturbances, frequent falls, left-sided torticollis and swallowing problems. MRI head showed a T2-hyperintense, partly exophytic mass lesion centred in the pontomedullary region, raising the possibility of diffuse midline glioma. The exophytic component was partially resected by suboccipital craniotomy, leaving intact the infiltrative component. Ventriculoperitoneal shunt was implanted due to postoperative hydrocephalus. Histological examination revealed a moderately cellular tumour consisted of bland glial cells infiltrating the brain parenchyma and radially arranged around the blood vessels. By immunohistochemistry, the tumour strongly expressed S100 and GFAP in addition to intense nestin positivity, while OLIG2 was negative in the perivascular tumour cells. DNA methylation array profiled the tumour as “methylation class diffuse astrocytoma, MYB or MYBL1-altered subtype B (infratentorial)” and an in-frame MYB::QKI fusion was identified by RNA sequencing, confirming the diagnosis of angiocentric glioma. The patient has been initially treated with angiogenesis inhibitor and mTOR inhibitor, and now he is receiving palliative vinblastine. He is clinically stable on 9 months follow-up.Conclusion: Brainstem AG may cause a diagnostic problem, and the surgical and oncological management is challenging due to unresectability and lack of response to conventional chemo-radiation. In the future, genetically-tailored therapies might improve the prognosis

Estimation of the detected background by the future gamma ray transient mission CAMELOT

This study presents a background estimation for the CubeSats Applied for MEasuring and LOcalising Transients (CAMELOT), which is a proposed fleet of nanosatellites for the all-sky monitoring and timing-based localization of gamma ray transients with precise localization capability at low Earth orbits. CAMELOT will allow us to observe and precisely localize short gamma ray bursts (GRBs) associated with kilonovae, long GRBs associated with core-collapse massive stars, magnetar outbursts, terrestrial gamma ray flashes, and gamma ray counterparts to gravitational wave sources. A fleet of at least nine 3U CubeSats is proposed to be equipped with large and thin CsI(Tl) scintillators read out by multipixel photon counters (MPPC). A careful study of the radiation environment in space is necessary to optimize the detector casing, estimate the duty cycle due to the crossing of the South Atlantic Anomaly and polar regions, and minimize the effect of the radiation damage of MPPCs

Photon-counting computed tomography in the assessment of rheumatoid arthritis-associated interstitial lung disease: an initial experience

PURPOSEInterstitial lung disease (ILD) accounts for a significant proportion of mortality and morbidity in patients with rheumatoid arthritis (RA). The aim of this cross-sectional study is to evaluate the performance of novel photon-counting detector computed tomography (PCD-CT) in the detection of pulmonary parenchymal involvement.METHODSSixty-one patients with RA without a previous definitive diagnosis of ILD underwent high-resolution (HR) (0.4 mm slice thickness) and ultra-high-resolution (UHR) (0.2 mm slice thickness) PCDCT examination. The extent of interstitial abnormalities [ground-glass opacity (GGO), reticulation, bronchiectasis, and honeycombing] were scored in each lobe using a Likert-type scale. Total ILD scores were calculated as the sum of scores from all lobes.RESULTSReticulation and bronchiectasis scores were higher in the UHR measurements taken compared with the HR protocol [median (quartile 1, quartile 3): 2 (0, 3.5) vs. 0 (0, 3), P < 0.001 and 2 (0, 2) vs. 0 (0, 2), P < 0.001, respectively]; however, GGO and honeycombing scores did not differ [2 (2, 4) vs. 2 (2, 4), P = 0.944 and 0 (0, 0) vs. 0 (0, 0), P = 0.641, respectively]. Total ILD scores from both HR and UHR scans showed a mild negative correlation in diffusion capacity for carbon monoxide (HR: r = –0.297, P = 0.034; UHR: r = –0.294, P = 0.036). The pattern of lung parenchymal involvement did not differ significantly between the two protocols. The HR protocol had significantly lower volume CT dose index [0.67 (0.69, 1.06) mGy], total dose length product [29 (24.48, 33.2) mGy*cm] compared with UHR scans [8.18 (6.80, 9.23) mGy, P < 0.001 and 250 (218, 305) mGy*cm, P < 0.001].CONCLUSIONUHR PCD-CT provides more detailed information on ILD in patients with RA than low-dose HR PCDCT. HR PCD-CT image acquisition with a low effective radiation dose may serve as a valuable, low-radiation screening tool in the selection of patients for further, higher-dose UHR PCD-CT screening

The peak-flux of GRB 221009A measured with GRBAlpha

The brightest gamma-ray burst ever observed, long-duration GRB 221009A, was detected by GRBAlpha nano-satellite without saturation. We present light curves of the prompt emission in 13 energy bands, from 80 keV to 950 keV, and perform a spectral analysis to calculate the peak flux and peak isotropic-equivalent luminosity. Since the satellite's attitude information is not available for the time of this GRB, more than 200 incident directions were probed in order to find the median luminosity and its systematic uncertainty. We found that the peak flux in the $80-800$ keV range (observer frame) was $F_{\rm{ph}}^{\rm{p}}=1300_{-200}^{+1200}$ ph cm$^{-2}$s$^{-1}$ or $F_{\rm{erg}}^{\rm{p}}=5.7_{-0.7}^{+3.7}\times10^{-4}$ erg cm$^{-2}$s$^{-1}$ and the fluence in the same energy range of the first GRB episode lasting 300 s, which was observable by GRBAlpha, was $S=2.2_{-0.3}^{+1.4}\times10^{-2}$ erg cm$^{-2}$ or $S^{\rm{bol}}=4.9_{-0.5}^{+0.8}\times10^{-2}$ erg cm$^{-2}$ for the extrapolated range of $0.9-8,690$ keV. We infer the isotropic-equivalent released energy of the first GRB episode to be $E_{\rm{iso}}^{\rm{bol}}=2.8_{-0.5}^{+0.8}\times10^{54}$ erg in the $1-10,000$ keV band (rest frame at $z=0.15$). The peak isotropic-equivalent luminosity in the $92-920$ keV range (rest frame) was $L_{\rm{iso}}^{\rm{p}}=3.7_{-0.5}^{+2.5}\times10^{52}$ erg s$^{-1}$ and the bolometric peak isotropic-equivalent luminosity was $L_{\rm{iso}}^{\rm{p,bol}}=8.4_{-1.5}^{+2.5}\times10^{52}$ erg s$^{-1}$ (4 s scale) in the $1-10,000$ keV range (rest frame). The peak emitted energy is $E_p^\ast=E_p(1+z)=1120\pm470$ keV. Our measurement of $L_{\rm{iso}}^{\rm{p,bol}}$ is consistent with the Yonetoku relation. It is possible that, due to the spectral evolution of this GRB and orientation of GRBAlpha at the peak time, the true values of peak flux, fluence, $L_{\rm{iso}}$, and $E_{\rm{iso}}$ are even higher. [abridged]Comment: 7 pages, 7 figures, 1 table, accepted for publication in Astronomy & Astrophysic