Glymphatic clearance is enhanced during sleep.

We here revisited the concept that glymphatic clearance is enhanced by sleep and anesthesia. Utilizing dynamic magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), and fluorescent fiber photometry, we report brain glymphatic clearance is enhanced by both sleep and anesthesia, and sharply suppressed by wakefulness. Another key finding was that less tracer enters the brains of awake animals and that brain clearance across different brain states can only be compared after adjusting for the injected tracer dose.

Response to Commentary on "Structural characterization of SLYM - a 4th meningeal membrane" by Julie Siegenthaler and Christer Betsholtz.

Histological studies have for decades documented that each of the classical meningeal membranes contains multiple fibroblast layers with distinct cellular morphology. Particularly, the sublayers of the arachnoid membranes have received attention due to their anatomical complexity. Early studies found that tracers injected into the cerebrospinal fluid (CSF) do not distribute freely but are restricted by the innermost sublayer of the arachnoid membrane. The existence of restrictions on CSF movement and the subdivision of the subarachnoid space into several distinct compartments have recently been confirmed by in vivo 2-photon studies of rodents, as well as macroscopic imaging of pigs and magnetic resonance imaging of human brain. Based on in vivo imaging and immunophenotyping characterization, we identified the structural basis for this compartmentalization of the subarachnoid space, which we term 'Subarachnoid lymphatic-like membrane', SLYM. The SLYM layer engages the subarachnoid vasculature as it approaches the brain parenchyma, demarcating a roof over pial perivascular spaces. Functionally, the separation of pial periarterial and perivenous spaces in the larger subarachnoid space is critical for the maintenance of unidirectional glymphatic clearance. In light of its close apposition to the pial surface and to the brain perivascular fluid exit points, the SLYM also provides a primary locus for immune surveillance of the brain. Yet, the introduction of SLYM, in terms of its anatomic distinction and hence functional specialization, has met resistance. Its critics assert that SLYM has been described in the literature by other terms, including the inner arachnoid membrane, the interlaminate membrane, the outer pial layer, the intermediate lamella, the pial membrane, the reticular layer of the arachnoid membrane or, more recently, BFB2-3. We argue that our conception of SLYM as an anatomically and functionally distinct construct is both necessary and warranted since its functional roles are wholly distinct from those of the overlying arachnoid barrier layer. Our terminology also lends clarity to a complex anatomy that has hitherto been ill-described. In that regard, we also note the lack of specificity of DPP4, which has recently been introduced as a 'selected defining marker' of the arachnoid barrier layer. We note that DPP4 labels fibroblasts in all meningeal membranes as well as in the trabecula arachnoides and the vascular adventitial layers, thus obviating its utility in meningeal characterization. Instead, we report a set of glymphatic-associated proteins that serve to accurately specify SLYM and distinguish it from its adjacent yet functionally distinct membranes.

Genome-Wide Association Analysis Identifies LILRB2 Gene for Pathological Myopia.

Pathological myopia (PM) is one of the leading causes of blindness, especially in Asia. To identify the genetic risk factors of PM, a two-stage genome-wide association study (GWAS) and replication analysis in East Asian populations is conducted. The analysis identified LILRB2 in 19q13.42 as a new candidate locus for PM. The increased protein expression of LILRB2/Pirb (mouse orthologous protein) in PM patients and myopia mouse models is validated. It is further revealed that the increase in LILRB2/Pirb promoted fatty acid synthesis and lipid accumulation, leading to the destruction of choroidal function and the development of PM. This study revealed the association between LILRB2 and PM, uncovering the molecular mechanism of lipid metabolism disorders leading to the pathogenesis of PM due to LILRB2 upregulation.

Trigeminal ganglion neurons are directly activated by influx of CSF solutes in a migraine model.

Classical migraine patients experience aura, which is transient neurological deficits associated with cortical spreading depression (CSD), preceding headache attacks. It is not currently understood how a pathological event in cortex can affect peripheral sensory neurons. In this study, we show that cerebrospinal fluid (CSF) flows into the trigeminal ganglion, establishing nonsynaptic signaling between brain and trigeminal cells. After CSD, ~11% of the CSF proteome is altered, with up-regulation of proteins that directly activate receptors in the trigeminal ganglion. CSF collected from animals exposed to CSD activates trigeminal neurons in naïve mice in part by CSF-borne calcitonin gene-related peptide (CGRP). We identify a communication pathway between the central and peripheral nervous system that might explain the relationship between migrainous aura and headache.

Intrinsic signaling pathways modulate targeted protein degradation.

Targeted protein degradation is a groundbreaking modality in drug discovery; however, the regulatory mechanisms are still not fully understood. Here, we identify cellular signaling pathways that modulate the targeted degradation of the anticancer target BRD4 and related neosubstrates BRD2/3 and CDK9 induced by CRL2VHL- or CRL4CRBN -based PROTACs. The chemicals identified as degradation enhancers include inhibitors of cellular signaling pathways such as poly-ADP ribosylation (PARG inhibitor PDD00017273), unfolded protein response (PERK inhibitor GSK2606414), and protein stabilization (HSP90 inhibitor luminespib). Mechanistically, PARG inhibition promotes TRIP12-mediated K29/K48-linked branched ubiquitylation of BRD4 by facilitating chromatin dissociation of BRD4 and formation of the BRD4-PROTAC-CRL2VHL ternary complex; by contrast, HSP90 inhibition promotes BRD4 degradation after the ubiquitylation step. Consequently, these signal inhibitors sensitize cells to the PROTAC-induced apoptosis. These results suggest that various cell-intrinsic signaling pathways spontaneously counteract chemically induced target degradation at multiple steps, which could be liberated by specific inhibitors.

Preserved walking function without postoperative reconstruction for pelvic Ewing's sarcoma: a case report.

BACKGROUND: Ewing's sarcoma is a primary bone tumor predominantly observed in children and adolescents, necessitating a multidisciplinary treatment approach. While localized cases have a 5-year survival rate of 60-70%, the prognosis is significantly worse in pelvic advanced cases with metastasis. Moreover, pelvic Ewing's sarcoma has the unique problem of leading to high rates of postoperative infection. CASE PRESENTATION: We present the case of a Japanese 14-year-old boy with left iliac Ewing's sarcoma and multiple metastases. At the initial visit, imaging revealed a large tumor in the left iliac bone with extraosseous extension and metastasis to multiple sites. Neoadjuvant chemotherapy resulted in significant tumor reduction. Surgical resection was performed without pelvic ring reconstruction to enable early postoperative chemotherapy and minimize postoperative infection risk. Despite complete abductor muscle removal, the patient achieved a stable gait postoperatively by centering the load axis. CONCLUSION: Our case highlights the successful management of a left iliac Ewing's sarcoma with multiple metastases, with a focus on functional preservation and infection risk reduction. Pelvic ring reconstruction was not performed to avoid postoperative complications, emphasizing the importance of early postoperative chemotherapy. The patient achieved a stable gait postoperatively, demonstrating the potential benefits of this approach in similar cases.

All-trans retinoic acid induces lipophagy by reducing Rubicon in Hepa1c1c7 cells.

All-trans retinoic acid (atRA), a metabolite of vitamin A, reduces hepatic lipid accumulation in liver steatosis model animals. Lipophagy, a new lipolysis pathway, degrades a lipid droplet (LD) via autophagy in adipose tissue and the liver. We recently found that atRA induces lipophagy in adipocytes. However, it remains unclear whether atRA induces lipophagy in hepatocytes. In this study, we investigated the effects of atRA on lipophagy in Hepa1c1c7 cells and the liver of mice fed a high-fat diet (HFD). First, we confirmed that atRA induced autophagy in Hepa1c1c7 cells by Western blotting and the GFP-LC3-mCherry probe. Next, we evaluated the lipolysis in fatty Hepa1c1c7 cells treated with the knockdown of Atg5, an essential gene in autophagy induction. Atg5-knockdown partly suppressed the atRA-induced lipolysis in fatty Hepa1c1c7 cells. We also found that atRA reduced the protein, but not mRNA, expression of Rubicon, a negative regulator of autophagy, in Hepa1c1c7 cells and the liver of HFD-fed mice. Rubicon-knockdown partly inhibited the atRA-induced lipolysis in fatty Hepa1c1c7 cells. In addition, atRA reduced hepatic Rubicon expression in young mice, but the effect of atRA on it diminished in aged mice. Finally, we investigated the mechanism underlying reduced Rubicon protein expression by atRA in hepatocytes. A protein synthesis inhibitor, but not proteasome or lysosomal inhibitors, significantly blocked the reduction of Rubicon protein expression by atRA in Hepa1c1c7 cells. These results suggest that atRA may promote lipophagy in fatty hepatocytes by reducing hepatic Rubicon expression via inhibiting protein synthesis.

Genetic Risk Stratification of Primary Open-Angle Glaucoma in Japanese Individuals.

PURPOSE: To assess the impact of genetic risk estimation for primary open-angle glaucoma (POAG) in Japanese individuals. DESIGN: Cross-sectional analysis. PARTICIPANTS: Genetic risk scores (GRSs) were constructed based on a genome-wide association study (GWAS) of POAG in Japanese people. A total of 3625 Japanese individuals, including 1191 patients and 2434 controls (Japanese Tohoku), were used for the model selection. We also evaluated the discriminative accuracy of constructed GRSs in a dataset comprising 1034 patients and 1147 controls (the Japan Glaucoma Society Omics Group [JGS-OG] and the Genomic Research Committee of the Japanese Ophthalmological Society [GRC-JOS]) and 1900 participants from a population-based study (Hisayama Study). METHODS: We evaluated 2 types of GRSs: polygenic risk scores using the pruning and thresholding procedure and a GRS using variants associated with POAG in the GWAS of the International Glaucoma Genetics Consortium (IGGC). We selected the model with the highest areas under the receiver operating characteristic curve (AUC). In the population-based study, we evaluated the correlations between GRS and ocular measurements. MAIN OUTCOME MEASURE: Proportion of patients with POAG after stratification according to the GRS. RESULTS: We found that a GRS using 98 variants, which showed genome-wide significance in the IGGC, showed the best discriminative accuracy (AUC, 0.65). In the Japanese Tohoku, the proportion of patients with POAG in the top 10% individuals was significantly higher than that in the lowest 10% (odds ratio [OR], 6.15; 95% confidence interval [CI], 4.35-8.71). In the JGS-OG and GRC-JOS, we confirmed similar impact of POAG GRS (AUC, 0.64; OR [top vs. bottom decile], 5.81; 95% CI, 3.79-9.01). In the population-based study, POAG prevalence was significantly higher in the top 20% individuals of the GRS compared with the bottom 20% (9.2% vs. 5.0%). However, the discriminative accuracy was low (AUC, 0.56). The POAG GRS was correlated positively with intraocular pressure (r = 0.08: P = 4.0 × 10-4) and vertical cup-to-disc ratio (r = 0.11; P = 4.0 × 10-6). CONCLUSIONS: The GRS showed moderate discriminative accuracy for POAG in the Japanese population. However, risk stratification in the general population showed relatively weak discriminative performance. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Comparison of a Novel Head-Mounted Objective Auto-perimetry (Gaze Analyzing Perimeter) and Humphrey Field Analyzer.

PURPOSE: To evaluate the agreement between 24-2 visual field (VF) test results obtained using the gaze analyzing perimeter (GAP; Findex) and the Humphrey field analyzer (HFA; Carl Zeiss Meditec). DESIGN: Cross-sectional study. PARTICIPANTS: Patients underwent HFA 24-2 for suspected or confirmed VF loss and were treated at the Kyoto University Hospital between December 2022 and July 2023. METHODS: Patients underwent consecutive VF tests on the same eye using HFA and GAP 24-2 tests. Bland-Altman analysis was used to compare GAP and HFA results. Examination points where the sensitivity measured using GAP was ≥ 10 dB higher than that measured using HFA were re-evaluated by referring back to the original gaze data; 2 ophthalmologists assessed whether the gaze moved linearly toward the new test target. MAIN OUTCOME MEASURES: Mean deviation (MD) and elapsed time on an individual basis and sensitivity on an examination point basis. RESULTS: Forty-seven eyes of 47 patients were analyzed. The correlation coefficient of the MD using HFA and GAP was 0.811 (95% confidence interval [CI]: 0.683-0.891). Bland-Altman analysis showed good agreement between HFA and GAP tests. The mean difference (95% limits of agreement) in MD between HFA and GAP results was -0.63 dB (-5.81 to 4.54 dB). Although no statistically significant differences were observed in the elapsed time (P = 0.99), measurements completed within 200 seconds were observed only in the GAP group (11 cases, 23.4%), who had significantly better HFA MD value than others (P = 0.001). On an examination point basis for sensitivity, the correlation coefficient between HFA and GAP was 0.691 (95% limits of agreement, 0.670-0.711). Original gaze data assessment revealed that the gaze moved linearly toward the new test target for 70.2% of the examination points with a sensitivity discrepancy. CONCLUSIONS: The results indicate that the GAP provides VF assessment outcomes comparable to those of the HFA. The GAP exhibited advantages in terms of testing time, particularly in patients with minimal VF impairment. Furthermore, the GAP records all eye movements, enabling the objective determination of VF abnormalities based on gaze patterns and facilitating easy posthoc verification. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Clinical Characteristics and Progression of Pachychoroid and Conventional Geographic Atrophy.

Purpose: To elucidate the clinical characteristics and progression rates of pachychoroid and conventional geographic atrophy (GA). Design: Retrospective, multicenter, observational study. Participants: A total of 173 eyes from 173 patients (38 eyes with pachychoroid GA and 135 with conventional GA) from 6 university hospitals in Japan were included. All patients were Japanese, aged ≥50 years and with fundus autofluorescence images having analyzable image quality. A total of 101 eyes (22 with pachychoroid GA and 79 with conventional GA) were included in the follow-up group. Methods: The studied eyes were classified as having pachychoroid or conventional GA; the former was diagnosed if the eye had features of pachychoroid and no drusen. The GA area was semiautomatically measured on fundus autofluorescence images, and the GA progression rate was calculated for the follow-up group. Multivariable linear regression analysis was used to determine whether the rate of GA progression was associated with GA subtype. Main Outcome Measures: Clinical characteristics and progression rates of pachychoroid and conventional GA. Results: The pachychoroid GA group was significantly younger (70.3 vs. 78.7 years; P < 0.001), more male-dominant (89.5 vs. 55.6%; P < 0.001), and had better best-corrected visual acuity (0.15 vs. 0.40 in logarithm of the minimum angle of resolution; P = 0.002), thicker choroid (312.4 vs. 161.6 µm; P < 0.001), higher rate of unifocal GA type (94.7 vs. 49.6%; P < 0.001), and smaller GA area (0.59 vs. 3.76 mm2;P < 0.001) than the conventional GA group. In the follow-up group, the mean GA progression rate (square-root transformation) was significantly lower in the pachychoroid GA group than in the conventional GA group (0.11 vs. 0.27 mm/year; P < 0.001). Conclusions: Demographic and ocular characteristics differed between GA subtypes. The progression rate of pachychoroid GA, adjusted for age and baseline GA area, was significantly lower than that of conventional GA. Japanese patients with conventional GA showed characteristics and progression rates similar to those in White populations. Some characteristics of GA in Japanese population differ from those in Waucasian populations, which may be due to the inclusion of pachychoroid GA. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Differences between pathologic and non-pathologic high myopia in 4-year outcomes of anti-VEGF therapy for macular neovascularization.

This retrospective observational study aimed to investigate the difference in 4-year outcomes of ranibizumab or aflibercept therapy for macular neovascularization (MNV) with high myopia between pathologic myopia (PM) and non-PM. This study was conducted at Kyoto University Hospital and included consecutive treatment-naïve eyes with active myopic MNV, in which a single intravitreal ranibizumab or aflibercept injection was administered, followed by a pro re nata (PRN) regimen for 4 years. Based on the META-PM study classification, eyes were assigned to the non-PM and PM groups. This study analyzed 118 eyes of 118 patients (non-PM group, 19 eyes; PM group, 99 eyes). Baseline, 1-year, and 2-year best-corrected visual acuity (BCVA) were significantly better in the non-PM group (P = 0.02, 0.01, and 0.02, respectively); however, the 3-year and 4-year BCVA were not. The 4-year BCVA course was similar in both groups. However, the total number of injections over 4 years was significantly higher in the non-PM than in the PM group (4.6 ± 2.6 vs. 2.9 ± 2.6, P = 0.001). Four-year BCVA significantly correlated only with baseline BCVA in both non-PM (P = 0.047, ß = 0.46) and PM groups (P < 0.001, ß = 0.59). In conclusion, over the 4-year observation period, the BCVA course after anti-VEGF therapy for myopic MNV was similar in the eyes with non-PM and those with PM; however, more additional injections in a PRN regimen were required in the eyes with non-PM compared to those with PM. Thus, more frequent and careful follow-up is required for the eyes with non-PM compared with those with PM to maintain long-term BCVA.

Off-camera gaze decreases evaluation scores in a simulated online job interview.

During the pandemic, digital communication became paramount. Due to the discrepancy between the placement of the camera and the screen in typical smartphones, tablets and laptops, mutual eye contact cannot be made in standard video communication. Although the positive effect of eye contact in traditional communication has been well-documented, its role in virtual contexts remains less explored. In this study, we conducted experiments to gauge the impact of gaze direction during a simulated online job interview. Twelve university students were recruited as interviewees. The interview consisted of two recording sessions where they delivered the same prepared speech: in the first session, they faced the camera, and in the second, they directed their gaze towards the screen. Based on the recorded videos, we created three stimuli: one where the interviewee's gaze was directed at the camera (CAM), one where the interviewee's gaze was skewed downward (SKW), and a voice-only stimulus without camera recordings (VO). Thirty-eight full-time workers participated in the study and evaluated the stimuli. The results revealed that the SKW condition garnered significantly less favorable evaluations than the CAM condition and the VO condition. Moreover, a secondary analysis indicated a potential gender bias in evaluations: the female evaluators evaluated the interviewees of SKW condition more harshly than the male evaluators did, and the difference in some evaluation criteria between the CAM and SKW conditions was larger for the female interviewees than for the male interviewees. Our findings emphasize the significance of gaze direction and potential gender biases in online interactions.

Polymorphism of Two-Dimensional Semiconducting Coordination Polymers: Impact of a Lead-Sulfur Network on Photoconductivity.

Sulfur-coordinated coordination polymers (S-CPs) have unique optoelectrical properties that originate from infinite M-S bond networks. In this study, we synthesized and characterized two polymorphs of a two-dimensional (2D) Pb(II) S-CP with a formula of [Pb(tzdt)(OAc)] (Htzdt=1,3-thiazolidine-2-thione, OAc=acetate). Our findings revealed that the thermodynamic product (KGF-26) possesses quasi-2D (-Pb-S-)n layers with weak nonbonded Pb-S bonds, whereas the kinetic product (KGF-27) has intrinsic 2D (-Pb-S-)n layers with Pb-S bonds. The results of time-resolved microwave conductivity measurements and first-principles calculations confirmed that KGF-27 exhibits higher photoconductivity than KGF-26, which establishes that the inorganic (-Pb-S-)n networks with Pb-S bonds are crucial for achieving high photoconductivity. This is the first experimental demonstration of the impact of the (-M-S-)n networks in S-CPs on photoconductivity through the comparison of crystal polymorphisms.

Human brain clearance imaging: Pathways taken by magnetic resonance imaging contrast agents after administration in cerebrospinal fluid and blood.

Over the last decade, it has become evident that cerebrospinal fluid (CSF) plays a pivotal role in brain solute clearance through perivascular pathways and interactions between the brain and meningeal lymphatic vessels. Whereas most of this fundamental knowledge was gained from rodent models, human brain clearance imaging has provided important insights into the human system and highlighted the existence of important interspecies differences. Current gold standard techniques for human brain clearance imaging involve the injection of gadolinium-based contrast agents and monitoring their distribution and clearance over a period from a few hours up to 2 days. With both intrathecal and intravenous injections being used, which each have their own specific routes of distribution and thus clearance of contrast agent, a clear understanding of the kinetics associated with both approaches, and especially the differences between them, is needed to properly interpret the results. Because it is known that intrathecally injected contrast agent reaches the blood, albeit in small concentrations, and that similarly some of the intravenously injected agent can be detected in CSF, both pathways are connected and will, in theory, reach the same compartments. However, because of clear differences in relative enhancement patterns, both injection approaches will result in varying sensitivities for assessment of different subparts of the brain clearance system. In this opinion review article, the "EU Joint Programme - Neurodegenerative Disease Research (JPND)" consortium on human brain clearance imaging provides an overview of contrast agent pharmacokinetics in vivo following intrathecal and intravenous injections and what typical concentrations and concentration-time curves should be expected. This can be the basis for optimizing and interpreting contrast-enhanced MRI for brain clearance imaging. Furthermore, this can shed light on how molecules may exchange between blood, brain, and CSF.

Lymphocyte Crossmatch Testing or Donor HLA-DP and -DQ Allele Typing Effectiveness in Single Cord Blood Transplantation for Patients With Anti-HLA Antibodies Other Than Against HLA-A, -B, -C, and -DRB1.

Anti-human leukocyte antigen (HLA) antibodies other than those against HLA-A, -B, -C, and DRB1 are a risk factor for engraftment delay and failure, especially in cord blood transplantation (CBT). The primary objective of this study was to assess the impact of the presence of anti-HLA antibodies on CBT and to evaluate the utility of lymphocyte crossmatch testing or additional HLA-DP and -DQ typing of CB units in improving transplant outcomes. We retrospectively assessed the engraftment rates and transplant outcomes of 772 patients who underwent their first CBT at our hospital between 2012 and 2021. Donors were routinely typed for HLA-A, -B, -C, and-DRB1 alleles, and the anti-HLA antibodies of recipients were screened before donor selection in all cases. Among patients who had antibodies against other than HLA-A, -B, -C, and DRB1 (n = 58), lymphocyte crossmatch testing (n = 32) or additional HLA-DP/-DQ alleles typing of CB (n = 15) was performed to avoid the use of units with corresponding alleles. The median patient age was 57 years (16 to 77). Overall, 75.7% had a high-risk disease status at transplantation, 83.5% received myeloablative conditioning regimens, and >80% were heavily transfused. Two hundred twenty-nine of the 772 recipients (29.6%) were positive for anti-HLA antibodies. There were no statistical differences in the number of infused CD34-positive cells between the anti-HLA antibody-positive and the anti-HLA antibody-negative patients. Of the 229 patients with anti-HLA antibodies, 168 (73.3%) had antibodies against HLA-A, -B, -C, and-DRB1 (Group A), whereas 58 (25.3%) had antibodies against HLA-DP, HLA-DQ, or -DRB3/4/5 with or without antibodies against HLA-A, -B, -C, and -DRB1 (Group B). No patients in both Groups A and B exhibited donor-specific anti-HLA antibodies against HLA-A, -B, -C, and -DRB1. The neutrophil engraftment rate was lower in patients with anti-HLA antibodies than in those without antibodies (89.9% versus 94.1%), whereas nonrelapse mortality (NRM) before engraftment was higher in antibody-positive patients (9.6% versus 4.9%). In patients who received 2 or more HLA allele-mismatched CB in the host-versus-graft (HVG) direction (n = 685), the neutrophil engraftment rate was lower in the anti-HLA antibody-positive recipients than in the antibody-negative recipients with significant differences (88.8% versus 93.8%) (P = .049). Similarly, transplant outcomes were worse in the antibody-positive patients with respect to 2-year overall survival (OS) (43.1% versus 52.3%) and NRM (44.0% versus 30.7%) than in the antibody-negative patients. In contrast, the results of Group B were comparable to those of the antibody-negative patients, while those of Group A were statistically worse than the antibody-negative patients in terms of all engraftment rate (88.6%), OS (34.2%), and NRM (49.0%). The presence of anti-HLA antibodies negatively impacts engraftment, NRM, and OS in CBT. However, HLA-DP/-DQ allele typing of CB units or lymphocyte crossmatch testing could be a useful strategy to overcome poor engraftment rates and transplant outcomes, especially in patients with anti-HLA antibodies against HLA-DP, HLA-DQ, or -DRB3/4/5.

Modeling of brain efflux: Constraints of brain surfaces.

Fluid efflux from the brain plays an important role in solute waste clearance. Current experimental approaches provide little spatial information, and data collection is limited due to short duration or low frequency of sampling. One approach shows tracer efflux to be independent of molecular size, indicating bulk flow, yet also decelerating like simple membrane diffusion. In an apparent contradiction to this report, other studies point to tracer efflux acceleration. We here develop a one-dimensional advection-diffusion model to gain insight into brain efflux principles. The model is characterized by nine physiological constants and three efflux parameters for which we quantify prior uncertainty. Using Bayes' rule and the two efflux studies, we validate the model and calculate data-informed parameter distributions. The apparent contradictions in the efflux studies are resolved by brain surface boundaries being bottlenecks for efflux. To critically test the model, a custom MRI efflux assay measuring solute dispersion in tissue and release to cerebrospinal fluid was employed. The model passed the test with tissue bulk flow velocities in the range 60 to 190 [Formula: see text]m/h. Dimensional analysis identified three principal determinants of efflux, highlighting brain surfaces as a restricting factor for metabolite solute clearance.

[Fulminant Clostridioides difficile infection during treatment with FLT3 inhibitor for acute myeloid leukemia].

An 80-year-old man with FLT3-TKD mutation-positive acute myeloid leukemia (AML) relapsed during consolidation therapy with venetoclax/azacitidine and was started on gilteritinib as salvage therapy. On the day after treatment initiation, febrile neutropenia was observed, but the fever resolved promptly after initiation of antimicrobial therapy. On the fifth day after completion of antimicrobial therapy, the patient experienced fever and watery diarrhea over 10 times a day, and a diagnosis of Clostridioides difficile infection (CDI) was made based on stool examination. The patient was treated with intravenous metronidazole, but renal dysfunction, hypotension, and hypoxemia developed, and a CT scan showed pleural and intraperitoneal effusion, significant intestinal wall thickening, and intestinal dilatation. Fidaxomicin was started under general monitoring in the intensive care unit and response was achieved. The patient was discharged from the intensive care unit on the 18th day after the onset of CDI. We report this case not only due to the rarity of fulminant CDI during AML treatment, but also because it is a valuable example of effective treatment of fulminant CDI with fidaxomicin.