Publications by authors named "Tetsuya Shimokawa"

We have investigated the hippocampal connectivity of the marmoset presubiculum (PreS) and reported that major connections of PreS in the rat were conserved in the marmoset. Moreover, our results indicated the presence of several additional projections that were almost absent in the rat brain, but abundant in the marmoset, such as direct projections from CA1 to PreS. However, little is known about the connectivity between the frontal brain regions and PreS or hippocampal formation.

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  • - This study assessed the healing of the tibial tuberosity in patients who had a specific type of leg surgery called medial opening wedge distal tibial tuberosity osteotomy (OWDTO) and looked for connections between healing and a condition known as lateral hinge fractures (LHFs).
  • - Data from 61 patients were analyzed, showing that while 13 patients experienced postoperative LHFs, all healed with conservative treatments within 6 months; factors like age and the angle of the tibia were linked to better healing outcomes.
  • - The findings concluded that LHFs significantly contributed to delayed healing of the tibial tuberosity, whereas the thickness of the osteotomy did not; thus, preventing LHFs is important for promoting healing
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  • - This study explored the relationship between MRI findings and actual tissue degeneration in the anterior cruciate ligament (ACL) of patients with knee osteoarthritis (OA), aiming to create a new grading system based on MRI results matching histological analysis.
  • - Researchers analyzed 106 ACL specimens from patients who had knee surgery, calculating the signal intensity of the ACL compared to muscle on MRI to assess degeneration.
  • - The findings showed a strong correlation between MRI signal intensity ratios and the degree of collagen degeneration, leading to a new grading system that classifies ACL degeneration into three levels, potentially improving diagnosis and treatment of knee OA.
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Introduction: Efficient learning is critical to adapting to different environments. There are well-known learning principles in cognitive rehabilitation, including errorless (EL) and trial-and-error (T&E) learning; however, little is known about their underlying neural mechanisms. In the current study, to understand the age-related changes in learning benefits and neural mechanisms applying EL and T&E learning methods in healthy middle-aged adults, we conducted a graph theoretical analysis using functional magnetic resonance imaging data and analyzed the relationship between learning benefits and age, as well as functional network connectivity and age, with both learning principles.

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  • The study investigates the impact of medial opening wedge distal tibial tuberosity osteotomy (OWDTO) on neuropathic pain (NP) in patients with knee osteoarthritis (OA), revealing a significant decrease in NP after surgery.
  • Fifty-two patients were assessed using the painDETECT questionnaire, and outcomes measured through WOMAC and Knee Society Score (KSS) show that preoperative NP correlates with higher pain and lower physical function scores.
  • Results suggest that OWDTO effectively alleviates knee symptoms and improves function, leading to increased patient satisfaction, particularly for those initially presenting with possible NP.
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Recent research has shown that the Default Mode Network (DMN) typically exhibits increased activation during processing of social and personal information but shows deactivation during working memory (WM) tasks. Previously, we reported the Frontal Parietal Network (FPN) and DMN showed coactivation during task preparation whereas the DMN exhibited deactivation during task execution in working memory tasks. Aging research has shown that older adults exhibited decreased functional connectivity in the DMN relative to younger adults.

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  • The study investigates how changes in the posterior tibial slope (PTS) affect clinical outcomes in cruciate-retaining total knee arthroplasty (CR-TKA), focusing on patient satisfaction and joint awareness.
  • Results show that patients with an increased PTS experienced significantly higher scores on the Knee Society Score (KSS) and lower scores on the Forgotten Joint Score-12 (FJS), indicating better overall symptoms and satisfaction.
  • Additionally, the study finds a correlation between PTS changes and decreased medial compartment loading, suggesting that increased PTS may lead to better outcomes due to reduced stress on the knee during flexion.
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Neural tube defects (NTDs) cause fetal and pediatric deaths or lifelong neurological disabilities. No effective treatment is currently available for NTDs. We attempted to elucidate the pathogenesis of NTDs and propose a therapeutic strategy.

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  • The study aimed to explore the link between neuropathic pain (NP) and radiological findings in knee osteoarthritis (OA) patients undergoing surgery.
  • Out of 197 patients, 34 were identified with possible NP, exhibiting higher central sensitization and worse symptoms compared to those with unlikely NP.
  • No specific radiological indicators were found to predict NP in knee OA; however, patients with possible NP tended to have more severe pain and reduced knee function.
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Background: Laparoscopic and robotic surgery for transverse colon cancer are difficult due to complex fusion of the foregut and midgut and variation of the vessels of the transverse colon. Although the vessels of the right colon have been investigated, middle colic artery (MCA) variation and the relationship with vessels around the transvers colon are unknown. We investigated variation of the MCA using computed tomography angiography (CTA) and cadaver specimen and the relationship between the superior mesenteric vein (SMV) and MCA using CTA.

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The rational inattention model has recently attracted much attention as a promising candidate to model bounded rationality in the research field of decision-making and game theory. However, in contrast to this energetic promotion of the theoretical works, empirical verification of the validity of the RI model has not progressed much. Furthermore, to our knowledge, the central assumption of the RI model, that the amount of mutual information obtained from signals adequately represents the cognitive cost of information, has not been tested from a neuroscientific perspective.

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Introduction: Containment of the further spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and reducing fatality due to coronavirus disease 19 (COVID-19) represent a pressing challenge to global health services. Here, we present a management blueprint for both the containment of SARS-CoV-2 and treatment of COVID-19 through a comprehensive approach.

Methodology: A cohort of 130 consecutive patients identified as positive for SARS-CoV-2 by testing of nasal swab by polymerase chain reaction were managed at a peripheral city of Bangladesh between 1 April and 31 May, 2020.

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The intrinsic functional network architecture accounts for task-evoked brain activity changes and variabilities in cognitive performance. Relationships between the intrinsic functional network architecture and task performance or learning ability have been previously reported. However, the relationships between learning benefits and the characteristics of intrinsic functional network architecture for different types of learning methods remain unclear.

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  • The study investigated how the surgeon's experience affects the reproducibility of joint gap measurements during manual stress in robotic-assisted total knee arthroplasty (TKA) and whether the distraction force remains consistent throughout the range of motion (ROM).
  • Results showed that an experienced surgeon achieved significantly larger joint gaps compared to an inexperienced surgeon, especially during specific flexion angles.
  • There was a correlation between the gap measurement differences and preoperative hip-knee-ankle (HKA) angles, suggesting that the surgical technique and patient anatomy both influence joint stability outcomes.
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Background: The purpose of this study was to investigate axial load resistance of the tibia depending on the thickness of tibial tuberosity osteotomy in medial open-wedge distal tuberosity proximal tibial osteotomy (OWDTO). The hypothesis is that a thin tibial tuberosity osteotomy shows high axial load resistance of the tibia.

Methods: The OWDTO model was constructed from imitation bones of the tibia.

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The marmoset (a New World monkey) has recently received much attention as an experimental animal model; however, little is known about the connectivity of limbic regions, including cortical and hippocampal memory circuits, in the marmoset. Here, we investigated the neuronal connectivity of the marmoset, especially focusing on the connectivity between the hippocampal formation and the presubiculum, using retrograde and anterograde tracers (cholera toxin-B subunit and biotin dextran amine). We demonstrated the presence of a direct projection from the CA1 pyramidal cell layer to the deep layers of the presubiculum in the marmoset, which was previously identified in the rabbit brain, but not in the rat.

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Background: Schizophrenia is a mental disorder caused by both environmental and genetic factors. Prenatal exposure to antipsychotics, an environmental factor for the fetal brain, induces apoptotic neurodegeneration and cognitive impairment of offspring similar to schizophrenia. The aim was to investigate molecular biological changes in the fetal hippocampus exposed to haloperidol (HAL) by RNA expression as a model of the disorder.

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Background: The function of the anterior cruciate ligament (ACL) in osteoarthritis (OA) of the knee remains to be elucidated. The purpose of this study is to evaluate histological changes of the ACL in end-stage knee OA and to clarify the relationship between histological changes in the ACL and knee function.

Hypothesis: The hypothesis in this study was that ACL degeneration in knee OA is associated with decreased knee function.

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Purpose: Although the joint gap distance and compartment loading of the knee are different parameters for obtaining balanced knees in patients with total knee arthroplasty (TKA), the extent to which a balanced knee is achieved in patients with mechanically aligned TKA (MA-TKA) is unclear. This study aimed to investigate the anatomical factors that affect the ligament balancing in MA-TKA according to a gap balancing technique by measured resection technique.

Methods: The relationship between compartment loading, gap distance, and lower limb alignment was analysed in forty-three patients who underwent navigation-assisted MA-TKA with the minimum soft-tissue release.

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  • - The study aimed to determine if the medial proximal tibial angle (MPTA) at the posterior tibial plateau can indicate the pre-arthritic MPTA in knees with advanced osteoarthritis (OA) that still have an intact anterior cruciate ligament (ACL).
  • - In the analysis of 100 OA knees, researchers examined the hip-knee-ankle (HKA) angles and MPTAs using computed radiography and computed tomography, discovering variations in MPTA measurements across different regions of the tibial plateau.
  • - The findings suggested that the MPTA at the posterior tibial plateau is reflective of the pre-arthritic MPTA in ACL-intact advanced OA knees, with significant correlations
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The aim of this study was to identify the functional connectivity and networks utilized during tool-use in real assembly workers. These brain networks have not been elucidated because the use of tools in real-life settings is more complex than that in experimental environments. We evaluated task-related functional magnetic resonance imaging in 13 assembly workers (trained workers, TW) and 27 age-matched volunteers (untrained workers, UTW) during a tool-use pantomiming task, and resting-state functional connectivity was also analyzed.

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Herein, we compared the connectivity of resting-state networks between participants with high and low working memory capacity groups. Brain network connectivity was assessed under both resting and working memory task conditions. Task scans comprised dual-task (reading sentences while memorizing target words) and single-task (reading sentences) conditions.

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Prosaposin (PSAP), a highly conserved glycoprotein, is a precursor of saposins A-D. Accumulating evidence suggests that PSAP is a neurotrophic factor, as well as a regulator of lysosomal enzymes. Recently, the orphan G-protein-coupled receptors GPR37 and GPR37L1 were recognized as PSAP receptors, but their functions have not yet been clarified.

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Study Design: Cross-sectional observational study.

Purpose: To examine whether pelvic rotation as a compensatory mechanism for sagittal imbalance is related to quality of life (QOL).

Overview Of Literature: Poor sagittal alignment is associated with compensatory pelvic retroversion and decreased QOL.

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Pareidolias are visual phenomena wherein ambiguous, abstract forms or shapes appear meaningful due to incorrect perception. In Parkinson's disease (PD), patients susceptible to visual hallucinations experience visuo-perceptual deficits in the form of pareidolias. Although pareidolias necessitate top-down modulation of visual processing, the cortical dynamics of internally generated perceptual priors on these visual misperceptions is unknown.

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