Publications by authors named "Tadashi Imaizumi"

3 Publications

  • Page 1 of 1

Visualization of cross-resistance between antimicrobial agents by asymmetric multidimensional scaling.

J Clin Pharm Ther 2021 Nov 24. Epub 2021 Nov 24.

Faculty of Management and Information Sciences, Tama University, Tokyo, Japan.

What Is Known And Objective: In our previous studies, we developed a cross-resistance rate (CRR) correlation diagram (CRR diagram) that visually captures the magnitude of CRRs between antimicrobials using scatter plots. We used asymmetric multidimensional scaling (MDS) to transform cross-resistance similarities between antimicrobials into a 2-dimensional map and attempted to visually express them. We also explored the antibiograms of Pseudomonas aeruginosa before and after the transfer to newly built hospitals, and we determined by the CRR diagram that the CRRs among β-lactam antimicrobials other than carbapenems decreased substantially with the facility transfer. The present study tests whether the analysis of CRRs by asymmetric MDS can be used as new visual information that is easy for healthcare professionals to understand.

Method: We tested the impact of changes in the nosocomial environment due to institutional transfers on CRRs among antimicrobials in asymmetric MDS, as well as contrasted the asymmetric MDS map and CRR diagram.

Results And Discussion: In the asymmetric MDS map, antimicrobial groups with the same mechanism of action were displayed close together, and antimicrobial groups with different mechanisms of action were displayed separately. The asymmetric MDS map drawn solely for antimicrobials belonging to the group with the same mechanism of action showed similarities to the CRR diagram. Also, the distance of each antimicrobial to other antimicrobials shown in the asymmetric MDS map was negatively correlated with the CRRs for them against that antimicrobial.

What Is New And Conclusion: The asymmetric MDS map expresses the dissimilarity as distances between agents, and there are no meanings or units on the ordinate and abscissa axes of the output map. In contrast, the CRR diagram expresses the antimicrobials' resistance status as values, such as resistance rate and CRR. By analysing the CRRs in the asymmetric MDS, it is feasible to visually recognize cross-resistance similarities between antimicrobial groups as distances. The use of the asymmetric MDS combined with the CRR diagram allows us to visually understand the resistance and cross-resistance status of each antimicrobial agent as a 2-dimensional map, as well as to understand the trends and characteristics of the data by means of quantitative values.
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November 2021

Prediction of clinical results of laminoplasty for cervical myelopathy focusing on spinal cord motion in intraoperative ultrasonography and postoperative magnetic resonance imaging.

Spine (Phila Pa 1976) 2009 Nov;34(24):2634-41

Department of Orthopedic Surgery, Kaikoukai Rehabilitation Hospital, and Department of Orthopedic Surgery, Nagoya University School and Graduate School of Medicine, Aichi-ken, Japan.

Study Design: Retrospective analysis of preoperative imaging and clinical data from patients undergoing cervical expansive laminoplasty for cervical myelopathy.

Objective: To investigate preoperative parameters that predict the floating status of the spinal cord at the anterior elements of the cervical spine in both intraoperative ultrasonography (US) and postoperative magnetic resonance imaging (MRI), and to evaluate the association between clinical outcome and spinal cord floating.

Summary Of Background Data: Intraoperative US has been used to evaluate the status of the spinal cord after cervical laminoplasty for cervical myelopathy. Few studies have evaluated the predictive preoperative parameters for intraoperative US results.

Methods: Imaging and clinical outcome data were collected from 101 consecutive patients who underwent cervical expansive laminoplasty for cervical myelopathy at Kaikoukai Nagoya Kyouritsu Hospital, Japan, from April 2004 to April 2008. The preoperative parameters associated with spinal cord floating in intraoperative US and postoperative MR images were investigated. Predictive parameters for the rate of recovery according to the Japanese Orthopedic Association score for cervical myelopathy at each follow-up session were also investigated.

Results: Predictive parameters for spinal cord floating after decompression in intraoperative US were the cervical vertebrae 2 to 7 (C2-C7) sagittal alignment in the standing neutral position on preoperative plain radiograph radiography (cut-off value=3 degrees) and the C5/6 "beak angle" in preoperative MRI (cut-off value=20 degrees). A predictive parameter for spinal cord floating in postoperative MRI was the C5/6 beak angle in preoperative MRI (cut-off value=21 degrees). The preoperative Japanese Orthopedic Association score and spinal cord floating at anterior elements of the cervical spine in intraoperative US were predictive parameters for clinical outcome.

Conclusion: Intraoperative US was more useful than postoperative MRI for predicting the clinical outcome of cervical expansive laminoplasty. Knowledge of the predictive parameters for spinal cord floating after cervical expansive laminoplasty could help evaluate the limitations of posterior decompression.
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November 2009

Prevalence of pancreatic cystic lesions including intraductal papillary mucinous neoplasms in patients with end-stage renal disease on hemodialysis.

Pancreas 2009 Mar;38(2):175-9

Department of Gastroenterology, Nagoya Kyoritsu Hospital, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.

Objectives: Pancreatic cystic (PC) lesions are not necessarily rare, and it is important to diagnose whether PC lesions are neoplastic such as intraductal papillary mucinous neoplasm (IPMN) because of its malignant potential. Reports on PC lesions in hemodialysis (HD) patients are remarkably limited. The aim of this study was to clarify the prevalence and characteristics of PC lesions in HD patients.

Methods: We reviewed 1012 consecutive HD patients and 11,100 patients (controls) without renal disease who underwent transabdominal ultrasonography between January 2003 and December 2005. Patients' sex ratio (female-to-male) was less, and the age was older in HD patients. Clinical findings of these patients were examined.

Results: The prevalence both of PC lesions and IPMNs was significantly higher in HD patients than in controls (9.3% vs 1.3% and 2.8% vs 0.2%, P < 0.0001). The incidence of IPMNs in HD patients with PC lesions was higher than that in controls with PC lesions (29.8% vs 17.0%, P = 0.021). Multivariate logistic regression analysis revealed that the odds ratios of PC lesions and IPMNs were 6.38 (95% confidence interval, 4.82-8.45) and 9.39 (95% confidence interval, 5.36-16.49) in HD patients compared with controls.

Conclusion: The prevalence of PC lesions in HD patients is higher, and HD patients with PC lesions have high prevalence of IPMNs.
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March 2009