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Spondyloarthritis is an inflammatory disease characterised by tendon adhesions and sacroiliitis. Herein, we present a case of reactive arthritis (ReA) after Chlamydia infection. The condition was characterised by rotator cuff enthesitis accompanied by inflammation of the rotator cuff muscles and presence of contrast-enhanced lesions at several tendon attachments without pelvic sacroiliitis. Some studies have reported about shoulder joint involvement observed on magnetic resonance imaging (MRI) in ankylosing spondylitis and psoriatic arthritis. However, there are no reports on shoulder lesions detected on MRI in C. trachomatis infection-associated ReA. The patient presented with hip, lower back and right shoulder pain. MRI of the pelvis revealed inflammation of the tendon attachments such as the spinous process, sciatic tuberosity and greater and lesser trochanter. However, sacroiliitis was not observed. These imaging findings indicated enthesitis. The patient tested positive for C. trachomatis immunoglobulin but negative for HLA-B27 antigen. Hence, he was diagnosed with Chlamydia-related ReA. Antibiotic treatment combined with sulfasalazine was initiated. This resulted in an evident clinical improvement without remission. To the best of our knowledge, this is the first case report showing the presence of shoulder lesions on MRI in C. trachomatis infection-associated ReA. Further, this study showed that shoulder lesions in spondyloarthritis, including ReA, are characterised by not only adhesive inflammation but also bone marrow oedema in the tendon attachments and rotator cuff inflammation., (© 2024 The Authors. Published by Elsevier Inc. on behalf of University of Washington.)

Postpolypectomy syndrome (PPS), also known as postpolypectomy coagulation syndrome or transmural burn syndrome, is a rare complication following colonic polypectomy characterized by abdominal pain, fever, and leukocytosis. Herein, we present a case of a patient in his 70s who developed abdominal pain and fever after a polypectomy. He was diagnosed with PPS, which rapidly progressed to septic shock necessitating left hemicolectomy. Pathological findings confirmed intestinal necrosis and severe electrocoagulation injury. Despite surgical intervention, the patient succum to multiple complications. While usually mild, approximately 0.07% of PPS cases require hospitalization due to localized peritonitis from electrocautery. Conservative management is effective, though severe complications are rare. Despite its generally favorable prognosis, our case highlights rapid progression to fatal septic shock postsurgery. Recognition of PPS is crucial, particularly in patients with abdominal pain postpolypectomy, as it can lead to life-threatening outcomes., (© 2024 The Authors.)

Cryptococcal meningitis is one of the most common fungal meningitis in adults and causes disabling morbidity and mortality worldwide. The occurrence of postinfectious inflammatory response syndrome during cryptococcal meningitis treatment presents a diagnostic challenge. This time course seems paradoxical because patients show worsening symptoms and imaging findings. However, laboratory data improve with antifungal treatments. Herein, we present a case of an older woman diagnosed with cryptococcal meningitis who later developed postinfectious inflammatory response syndrome. Despite the initial antifungal treatment and improvements in cerebrospinal fluid analysis results, the patient's neurological condition deteriorated; imaging findings worsened. Magnetic resonance imaging at the time of postinfectious inflammatory response syndrome showed more prominent meningeal enhancement and brain edema, consistent with postinfectious inflammatory response syndrome, combined with negative repeat cerebrospinal fluid cultures for cryptococcal species. This case highlights the importance of considering postinfectious inflammatory response syndrome when patients with cryptococcal meningitis show clinical worsening during treatment. Prompt corticosteroid therapy significantly improves patient outcomes. Radiologists and clinicians should be aware of postinfectious inflammatory response syndrome to provide appropriate therapeutic options and improve prognosis in patients with cryptococcal meningitis., (Published by Elsevier Inc. on behalf of University of Washington.)

In 2004, the equine-origin H3N8 canine influenza virus (CIV) first caused an outbreak with lethal cases in racing greyhounds in Florida, USA, and then spread to domestic dogs nationwide. Although transmission of this canine virus to humans has not been reported, it is important to evaluate its zoonotic potential because of the high contact opportunities between companion dogs and humans. To gain insight into the interspecies transmissibility of H3N8 CIV, we tested its adaptability to human respiratory A549 cells through successive passages. We found that CIV acquired high growth properties in these cells mainly through mutations in surface glycoproteins, such as hemagglutinin (HA) and neuraminidase (NA). Our reverse genetics approach revealed that HA2-K82E, HA2-R163K, and NA-S18L mutations were responsible for the increased growth of CIV in human cells. Molecular analyses revealed that both HA2 mutations altered the optimum pH for HA membrane fusion activity and that the NA mutation changed the HA-NA functional balance. These findings suggest that H3N8 CIV could evolve into a human pathogen with pandemic potential through a small number of mutations, thereby posing a threat to public health in the future., (© 2024. The Author(s).)

Hashimoto's encephalopathy is an autoimmune disease characterized by diverse clinical and imaging manifestations, often presenting considerable challenges in its diagnosis, especially when myelitis occurs before the onset of encephalopathy. Anti-N-terminal of α-enolase antibodies targeting the N-terminal of α-enolase are specific serum markers of Hashimoto's encephalopathy; however, studies analyzing their association with myelitis are lacking. Herein, we describe the case of a patient with myelitis who later developed encephalopathy. Owing to positivity for anti-N-terminal of α-enolase antibodies in the serum, a diagnosis of Hashimoto's encephalopathy was made. Detecting anti-NAE antibodies can be useful in diagnosing myelitis of unknown etiology., (© 2024 The Authors.)

Background: Treponema pallidum can invade the central nervous system (CNS) early in its infection, causing neurosyphilis. Neurosyphilis typically presents with meningovasculitis in the acute or subacute phase, while tabes dorsalis and dementia paralytica are classical conditions in the later stages. However, syphilis is often misdiagnosed as other conditions such as tumors or autoimmune diseases including vasculitis and encephalitis, which is why the condition is known as "The Great Mimicker." The increasing incidence of syphilis in recent years emphasizes the importance of early diagnosis and treatment; however, its multiple clinical manifestations impose diagnostic challenges for clinicians because it resembles other diseases. In this case series, we present the impressive manifestations of neurosyphilis through three unique radiological presentations., Case Presentation: Case 1 details optic nerve involvement in an HIV-positive male, where MRI and fundoscopic findings confirmed syphilitic optic neuritis. Case 2 describes a patient in her pregnancy initially suspected of acoustic neuroma on MRI, later diagnosed with syphilitic gumma affecting the inner ear canal. Case 3 is a young male with clinical features mimicking temporal arteritis, ultimately identified as skull osteomyelitis secondarily causing inflammation of the musculus temporalis and meningitis., Conclusions: These cases underscore the necessity of considering syphilis in differential diagnoses, given the diversity of its clinical presentations. Radiology plays an important role in avoiding unnecessary interventions. The increasing prevalence of recurrent syphilis imposes diagnostic challenges, emphasizing the importance of the early diagnosis and treatment of neurosyphilis by clinicians., (© 2024. The Author(s).)

Photochromism through excited-state intermolecular proton transfer (ESInterPT) processes based on keto-enol tautomerization was found in phenazine-2,3-diol PD1 and its monoalkoxy derivative PD2 in a glassy matrix at 77 K: the colorless solutions of enol forms PD1-E and PD2-E at 298 K transformed into orange-colored solutions of keto forms PD1-K and PD2-K upon photoirradiation ( λ = 385 nm) at 77 K. Furthermore, this report is the first to achieve the single-crystal X-ray structural analyses of phenazine-2,3-diol PD1 and its monoalkoxy derivative PD2, since the report on the synthesis of PD1 70 years ago. Indeed, it was found that PD1 and PD2 molecules exist in the keto form (PD1-K) and the enol form (PD2-E), respectively, in the crystal, and the neighboring PD1-K and PD2-E molecules are linked by one-dimensional intermolecular NH⋯O and OH⋯N hydrogen bonding, respectively. The fact suggests strongly that for PD1 and PD2, the formation of continuous intermolecular hydrogen bonding in aggregates such as in a glassy matrix at 77 K is involved in the keto-enol tautomerization of phenazine-2,3-diol derivatives based on ESInterPT. More interestingly, the color and the photoabsorption spectrum of the solids obtained by sublimation of crystals of PD2-E are similar to those for the crystals of PD1-K, indicating that the PD2 molecule exists in the keto form (PD2-K) in the solid of the sublimate. Therefore, this study provides a valuable insight for a greater understanding of the keto-enol tautomerization of diazaacene-diol derivatives and their photophysical properties in the solution and in the solid state.

Brain-derived neurotrophic factor (BDNF), one of the neurotrophins, and its specific receptor TrkB, are abundantly distributed in the central nervous system (CNS) and have a variety of biological effects, such as neural survival, neurite elongation, neural differentiation, and enhancing synaptic functions. Currently, there are two TrkB subtypes: full-length TrkB (TrkB-FL), which has a tyrosine kinase in the intracellular domain, and TrkB-T1, which is a tyrosine kinase-deficient form. While TrkB-FL is a typical tyrosine kinase receptor, TrkB-T1 is a main form expressed in the CNS of adult mammals, but its function is unknown. In this study, we performed fluorescent staining of the cerebral cortex of adult mice, by using TrkB-T1 antiserum and various antibodies of marker molecules for neurons and glial cells. We found that TrkB-T1 was expressed not only in neurons but also in astrocytes. In contrast, little expression of TrkB-T1 was found in oligodendrocytes and microglia. TrkB-T1 was expressed in almost all of the cells expressing TrkB-FL, indicating the direct interaction between TrkB subtypes. These findings suggest that a part of various functions of BDNF-TrkB signaling might be due to the interaction and cellular localization of TrkB subtypes in the cerebral cortex., Competing Interests: Declaration of competing interest Author declares no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Influenza D virus (IDV) is one of the causative agents of bovine respiratory disease complex, which is the most common and economically burdensome disease affecting the cattle industry, and the need for an IDV vaccine has been proposed to enhance disease control. IDVs are classified into five genetic lineages based on the coding sequences of the hemagglutinin-esterase-fusion (HEF) protein, an envelope glycoprotein, which is the main target of protective antibodies against IDV infection. Herein, we prepared a panel of monoclonal antibodies (mAbs) against the HEF protein of viruses of various lineages to investigate the antigenic characteristics of IDVs and found that the mAbs could be largely separated into three groups. The first, second, and third groups demonstrated lineage-specific reactivity, cross-reactivity to viruses of multiple but not all lineages, and cross-reactivity to viruses of all lineages, respectively. Analyzing the escape mutant viruses from virus-neutralizing mAbs revealed that the receptor-binding region of the HEF molecule harbors virus-neutralizing epitopes that are conserved across multiple lineage viruses. In contrast, the apex region of the molecule possessed epitopes unique to each lineage virus. Furthermore, reverse genetics-generated recombinant viruses with point mutations revealed that amino acids within positions 210-214 of the HEF protein determined the antigenic specificity of each lineage virus. Taken together, this study reveals considerable antigenic variation among IDV lineages, although they are presumed to form a single serotype in terms of HEF antigenicity. Characterization of the antigenic epitope structure of HEF may contribute to selecting and creating effective vaccine viruses against IDV.IMPORTANCEInfluenza D viruses (IDVs) are suggested to create cross-reactive single serotypes in hemagglutinin-esterase-fusion (HEF) antigenicity, as indicated by serological analyses among distinct HEF lineage viruses. This is supported by the high identities of HEF gene sequences among strains, unlike the hemagglutinin (HA) genes of the influenza A virus that exhibit HA subtypes. Herein, we analyzed HEF antigenicity using a monoclonal antibody panel prepared from several virus lineages and found the existence of lineage-conserved and lineage-specific epitopes in HEF molecules. These findings confirm the HEF commonality and divergence among IDVs and provide useful information for constructing a vaccine containing a recombinant IDV virus with an engineered HEF gene, thereby leading to broad immunogenicity., Competing Interests: The authors declare no conflict of interest.

Introduction: In transbronchial biopsy of peripheral pulmonary lesions, the bronchoscope can reach only a limited depth due to the progressive narrowing of bronchi, which may reduce the diagnostic rate. This study examined the balloon dilatation for bronchoscope delivery (BDBD) technique, employing a novel balloon device to enhance bronchoscopy into the peripheral lung areas., Methods: Anaesthetised swine served as our primary model. Using computed tomography (CT) scans, we positioned virtual targets characterised by a positive bronchus sign and a diameter of 20 mm beneath the pleura. The bronchoscope was navigated along the pathways determined from the CT images. We performed balloon dilatation when bronchial narrowing obstructed progress to assess whether balloon dilatation would enable the bronchoscope to enter further into the periphery., Results: We established 21 virtual targets on the CT scans. An average of 12.1 branches were identified along the pathways on the CT scans; however, bronchoscopy without BDBD only allowed access to an average of 6.7 branches. Based on 72 balloon dilatations with 3.0-mm or 4.0-mm ultra-thin bronchoscopes, there was an average increased access of 3.43 and 5.14 branches per route, respectively, with no significant BDBD complications. The bronchoscope was able to reach the planned location along all pathways, and the mean final bronchoscopic endpoints were at an average distance of 14.7 mm from the pleura. Post-procedure CT confirmed biopsy accuracy., Conclusion: The BDBD technique can enhance access of a flexible bronchoscope into the peripheral lung fields, which could potentially allow more accurate transbronchial interventions for peripheral targets., (© 2024 S. Karger AG, Basel.)