356 research outputs found

    Cyclotron resonance and mass enhancement by electron correlation in KFe2_2As2_2

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    Cyclotron resonance (CR) measurements for the Fe-based superconductor KFe2_2As2_2 are performed. One signal for CR is observed, and is attributed to the two-dimensional α\alpha Fermi surface at the Γ\Gamma point. We found a large discrepancy in the effective masses of CR [(3.4±\pm0.05)mem_e (mem_e is the free electron mass)] and de-Haas van Alphen (dHvA) results, a direct evidence of mass enhancement due to electronic correlation. A comparison of the CR and dHvA results shows that both intra- and interband electronic correlations contribute to the mass enhancement in KFe2_2As2_2.Comment: 5 pages, 4 figure

    Swallowing-like activity elicited in neonatal rat medullary slice preparation

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    Kondo T., Yamanishi T., Nishio T., et al. Swallowing-like activity elicited in neonatal rat medullary slice preparation. Brain Research 1837, 148955 (2024); https://doi.org/10.1016/j.brainres.2024.148955.Swallowing is induced by a central pattern generator in the nucleus tractus solitarius (NTS). We aimed to create a medullary slice preparation to elucidate the neural architecture of the central pattern generator of swallowing (Sw-CPG) and record its neural activities. Experiments were conducted on 2-day-old Sprague–Dawley rats (n = 46). The brainstem-spinal cord was transected at the pontomedullary and cervicothoracic junctions; the medulla was sliced transversely at thicknesses of 600, 700, or 800 μm. The rostral end of the slice was 100 μm rostral to the vagus nerve. We recorded hypoglossal nerve activity and electrically stimulated the vagus nerve or microinjected bicuculline methiodide (BIC) into the NTS. The 800-μm slices generated both rhythmic respiratory activity and electrically elicited neural activity. The 700-μm slices generated only respiratory activity, while the 600-μm slices did not generate any neural activity. BIC microinjection into the NTS in 800-μm slices resulted in the typical activity that closely resembled the swallowing activity reported in other experiments. This swallowing-like activity consistently lengthened the respiratory interval. Despite complete inhibition of respiratory activity, weak swallowing-like activity was observed under bath application of a non-NMDA receptor antagonist. Contrastingly, bath application of NMDA receptor antagonists resulted in a complete loss of swallowing-like activity and no change in respiratory activity. These results suggest that the 800-μm medullary slice preparation contains both afferent and efferent neural circuits and pattern generators of swallowing activity. Additionally, NMDA receptors may be necessary for generating swallowing activity. This medullary slice preparation can therefore elucidate Sw-CPG neural networks

    Methotrexate-associated lymphoproliferative disorder with multiple pulmonary nodules and bilateral cervical lymphadenopathy

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    As has been well recognized, methotrexate (MTX) leads to a state of immunosuppression and can provide a basis for the development of lymphoproliferative disorders (LPDs). MTX-associated LPDs can affect nodal sites as well as extranodal sites, though the manifestation of an LPD in the form of multiple pulmonary nodules is rare. Here, we report two cases of MTX-associated LPD with multiple bilateral pulmonary nodules, which was a finding suggestive of lung cancer, and bilateral cervical lymphadenopathy. After withdrawal of MTX, the multiple bilateral pulmonary nodules and bilateral cervical lymphadenopathy disappeared without chemotherapy in both cases. From these results, patients with pulmonary nodules and cervical lymphadenopathy should be examined for head and neck malignant tumors. Also, physicians should carefully check the administration of MTX. In patients with an MTX-associated LPD, we need to make an early diagnosis and consider discontinuing the administration of MTX as soon as possible

    Novel and recurrent COMP gene variants in five Japanese patients with pseudoachondroplasia: skeletal changes from the neonatal to infantile periods

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    Pseudoachondroplasia (PSACH) is an autosomal dominant skeletal dysplasia caused by pathogenic variants of cartilage oligomeric matrix protein (COMP). Clinical symptoms of PSACH are characterized by growth disturbances after the first year of life. These disturbances lead to severe short stature with short limbs, brachydactyly, scoliosis, joint laxity, joint pain since childhood, and a normal face. Epimetaphyseal dysplasia, shortened long bones, and short metacarpals and phalanges are common findings on radiological examination. Additionally, anterior tonguing of the vertebral bodies in the lateral view is an important finding in childhood because it is specific to PSACH and normalizes with age. Here, we report five Japanese patients with PSACH, with one recurrent (p.Cys351Tyr) and four novel heterozygous pathogenic COMP variants (p.Asp437Tyr, p.Asp446Gly, p.Asp507Tyr, and p.Asp518Val). These five pathogenic variants were located in the calcium-binding type 3 (T3) repeats. In four of the novel variants, the affected amino acid was aspartic acid, which is abundant in each of the eight T3 repeats. We describe the radiological findings of these five patients. We also retrospectively analyzed the sequential changes in the vertebral body and epimetaphysis of the long bones from the neonatal to infantile periods in a patient with PSACH and congenital heart disease

    Development of a new method for assessing otolith function in mice using three-dimensional binocular analysis of the otolith-ocular reflex

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    In the interaural direction, translational linear acceleration is loaded during lateral translational movement and gravitational acceleration is loaded during lateral tilting movement. These two types of acceleration induce eye movements via two kinds of otolith-ocular reflexes to compensate for movement and maintain clear vision: horizontal eye movement during translational movement, and torsional eye movement (torsion) during tilting movement. Although the two types of acceleration cannot be discriminated, the two otolith-ocular reflexes can distinguish them effectively. In the current study, we tested whether lateral-eyed mice exhibit both of these otolith-ocular reflexes. In addition, we propose a new index for assessing the otolith-ocular reflex in mice. During lateral translational movement, mice did not show appropriate horizontal eye movement, but exhibited unnecessary vertical torsion-like eye movement that compensated for the angle between the body axis and gravito-inertial acceleration (GIA; i.e., the sum of gravity and inertial force due to movement) by interpreting GIA as gravity. Using the new index (amplitude of vertical component of eye movement)/(angle between body axis and GIA), the mouse otolith-ocular reflex can be assessed without determining whether the otolith-ocular reflex is induced during translational movement or during tilting movement

    Growth inhibitory effects of antifolates against an adriamycin-resistant human small cell lung cancer cell line

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    We have established an Adriamycin (ADM) -resistant small cell lung cancer (SCLC) cell line, SBC-3/ADM100, which shows multifactorial mechanisms of resistance to ADM, such as overexpression of P-glycoprotein, an enhanced detoxifying system and a decrease in topoisomerase II activity. In the present study, we confirmed that SBC-3/ADM 100 showed collateral sensitivity to methotrexate and TNP-351, a new antifolate, though this cell line showed a typical multidrug resistance (MDR) pattern. We also demonstrated a faster uptake and higher accumulation (1.3-fold) of TNP-351 in the SBC-3/ADM100 cells than those in the parent SBC-3 cells. These results explain one of the mechanisms for collateral sensitivity in the resistant cells. Furthermore, this cell line was found to have no cross-resistance to edatrexate and minimal cross-resistance to trimetrexate, 254-S (cisplatin analog), 5-fluorouracil and 4-hydroperoxyifosfamide. These drugs will have clinical importance in patients with SCLC who were previously treated with an ADM-containing regimen. Thus, antifolates, especially TNP-351 and edatrexate, can be expected to eradicate residual multidrug resistant SCLC cells selected by ADM.</p

    RUPTURED CEREBRAL ANEURYSMS AND SEVERE PD

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    BACKGROUND: The pathophysiology of subarachnoid hemorrhages (SAHs) due to ruptured intracranial aneurysms (IAs) remains unclear.Although a relationship between SAHs and periodontal disease (PD) has been suggested, the mechanism requires clarification. OBJECTIVE: To evaluate the relationship between PD and SAHs and to identify periodontal pathogens associated with SAHs. METHODS: This prospective study included consecutive patients with ruptured (n = 11) and unruptured (n = 14) IAs and healthy controls (n = 8). The plasma and plaque subgingival bacterial deoxyribonucleic acid (DNA) levels in PD were evaluated by a dentist using the Community Periodontal Index of Treatment Needs (CPITN). Plasma levels of matrix metalloproteinase (MMP-9), tissue inhibitors of matrix metalloproteinase (TIMP2), and procollagen I were analyzed. RESULTS: Patients with ruptured IAs, had significantly higher CPITN scores than the controls, suggesting that ruptured IAs were associated with severe PD. Although no rupture-specific bacteria were identified, the positive rate of plaque subgingival bacterial DNA was significantly higher in patients with severe PD than in those without severe PD. Multivariate logistic regression analysis indicated that bleeding on probing (BOP)was associated with ruptured IAs (odds ratio, 1.10; 95% confidence interval 1.04–1.20; P = .0001). BOP was positively associated with plasma MMP-9 levels and a disequilibrium in the MMP-9/TIMP2 ratio. BOP was negatively correlated with plasma procollagen I levels (P < .05, for each). This suggested that local inflammation with severe PD might have systemic effects and lead to ruptured IAs. CONCLUSION: Disequilibrium of plasma protease/anti-protease associated with a high BOP rate in severe PD may be attributable to IA rupture
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