Effect of acid suppressant medications on the laxative action of magnesium preparations in patients with opioid-induced constipation: A pharmacovigilance analysis of the FDA Adverse Event Reporting System

Objective: Magnesium oxide is widely used for treating opioid-induced constipation, a serious analgesic-associated problem. Opioid analgesic users are often prescribed non-steroidal anti-inflammatory drugs, which are sometimes combined with acid suppressants to prevent gastrointestinal adverse events. Magnesium preparations combined with acid suppressants may diminish magnesium preparations' laxative effect. This study was aimed at evaluating the effect of magnesium preparations combined with acid suppressants on the incidence of opioid-induced constipation by using the Food and Drug Administration Adverse Event Reporting System. Methods: Adverse events were defined per the Medical Dictionary for Regulatory Activities; the term 'constipation (preferred term code: 10010774)' was used for analysis. After adjusting for patient background factors using propensity score matching, acid suppressants' effect on constipation incidence was evaluated in opioid users prescribed magnesium preparations alone as laxatives by using a test for independence. Key Findings: The Food and Drug Administration Adverse Event Reporting System contains 14,475,614 reports for January 2004 to December 2021. Significantly increased constipation incidence was related to magnesium preparations combined with acid suppressants, especially proton pump inhibitors (P < 0.0001, McNemar's test). Conclusion: Magnesium preparations combined with acid suppressants may diminish magnesium preparations' laxative effect; healthcare professionals should pay attention to this issue.

Effects of cyclic stretching exercise on long-lasting hyperalgesia, joint contracture, and muscle injury following cast immobilization in rats

The effects of exercise on mechanical hyperalgesia, joint contracture, and muscle injury resulting from immobilization are not completely understood. This study aimed to investigate the effects of cyclic stretching on these parameters in a rat model of chronic post-cast pain (CPCP). Seventeen 8-week-old Wistar rats were randomly assigned to (1) control group, (2) immobilization (CPCP) group, or (3) immobilization and stretching exercise (CPCP+STR) group. In the CPCP and CPCP+STR groups, both hindlimbs of each rat were immobilized in full plantar flexion with a plaster cast for a 4-week period. In the CPCP+STR group, cyclic stretching exercise was performed 6 days/week for 2 weeks, beginning immediately after cast removal prior to reloading. Although mechanical hyperalgesia in the plantar skin and calf muscle, ankle joint contracture, and gastrocnemius muscle injury were observed in both immobilized groups, these changes were significantly less severe in the CPCP+STR group than in the CPCP group. These results clearly demonstrate the beneficial effect of cyclic stretching exercises on widespread mechanical hyperalgesia, joint contracture, and muscle injury in a rat model of CPCP.

Prospective validation of 0-hour/1-hour algorithm using high-sensitivity cardiac troponin I in Japanese patients presenting to emergency department

Background

The diagnostic performance of 0-hour/1-hour algorithm using high-sensitivity cardiac troponin I (hsTnI) for non-ST-segment elevation myocardial infarction (NSTEMI) has not been evaluated in an Asian population.

Purpose

We aimed to prospectively validate the 0-hour/1-hour algorithm using hsTnI in a Japanese population.

Method

We enrolled 754 Japanese patients (mean age of 70 years, 395 men) presenting to our emergency department with symptoms suggestive of NSTEMI. The hsTnI concentration was measured using the Siemens ADVIA Centaur hsTnI assay at presentation and after 1 hour. Patients were divided into three groups according to the algorithm: hsTnI below 3 ng/L (only applicable if chest pain onset &gt;3 hours) or below 6 ng/L and delta 1 hour below 3 ng/L were the “rule-out” group; hsTnI at least 120 ng/L or delta 1 hour at least 12 ng/L were in the “rule-in” group; the remaining patients were classified as the “observe” group. Based on the Fourth Universal Definition of Myocardial Infarction, the final diagnosis was adjudicated by 2 independent cardiologists using all available information, including coronary angiography, coronary computed tomography, and follow-up data. Safety of rule-out was quantified by the negative predictive value (NPV) for NSTEMI, accuracy of rule-in by the positive predictive value (PPV), and overall efficacy by the proportion of patients triaged towards rule-out or rule-in within 1 hour.

Results

Prevalence of NSTEMI was 6.5%. The safety of rule-out (NPV 100%), accuracy of rule-in (PPV 26%), and overall efficacy (54%) were shown in Figure.

Conclusion

The 0-hour/1-hour algorithm using hsTnI is very safe and effective in triaging Japanese patients with suspected NSTEMI.

Funding Acknowledgement

Type of funding source: None

Abstract TP323: The Relationships Among Hospital Volume, Processes of Care and Patient Outcome in Ischemic Stroke: J-ASPECT Study

Introduction: Higher hospital volumes have been related to better outcomes in previous researches. However, the mechanisms of the volume-outcome relationships in stroke have not been sufficiently figured out. The aim of this study is to uncover the roles of processes in acute phase stroke care among the volume-outcome relationships.

Hypothesis: Processes of care mediate the volume-outcome relationships in stroke patients.

Methods: We analyzed 45,598 acute ischemic stroke patients in 267 certified training hospitals in Japan. Data between April 1,2011 and May 31, 2012 was obtained from Japanese Diagnosis Procedure Combination Database. We divided annual hospital case volumes into two groups: high-volume and low-volume. Main outcome was 30-day mortality. We set following process of care as mediators: early initiation of aspirin prescription (less than 24 hours) and early initiation of stroke rehabilitation (less than 3 days). Multilevel mediation models were performed adjusting for age, gender, comorbidities, Charlson comorbidity index to examine the relationships among hospital volume, processes of care and outcome.

Results: The early initiation of aspirin increased from 19.4% to 24.1%, the early initiation of rehabilitations increased from 59.6% to 65.6% and 30-day mortality decreased from 6.1% to 4.2%, for low-volume and high-volume hospitals. In the multilevel logistic regression analyses, admission to high-volume hospitals had 38% increased odds (OR = 1.38; 95% CI, 1.02-1.88) and 118% increased odds (OR = 2.18; 95% CI, 1.59-2.98) of early aspirin and rehabilitation initiation, compared with low-volume hospitals. Before adjusting for processes of care, admissions to high-volume hospitals had 30% decreased odds of death compared with admission to low-volume hospitals (OR = 0.70; 95% CI, 0.61-0.81). When processes of care were further adjusted, the volume-mortality relationship became non-significant. The early initiation of aspirin and rehabilitation accounted for 71% of the relationship (the regression coefficient was reduced from -0.355 to -0.102 when adjusted for processes of care).

Conclusions: Processes of care mediated the volume-outcome relationships in stroke patients.

Abstract WMP33: Effects of Organized Stroke Care on In-hospital Mortality and Morbidity of Patients With Ischemic and Hemorrhagic Stroke: J-ASPECT Study

Introduction: Organized stroke care is an integrated approach to managing stroke to improve outcomes. However, the effectiveness of organized stroke care on mortality and morbidity remains uncertain. This study aimed to examine whether Organized stroke care index (OCI), which graded 0-3 based on the presence of rehabilitation, stroke team assessment, and admission to a stroke unit, developed to assess the accessibility to stroke care by Saposnik (Neurology 2010) influenced stroke outcomes in a nation wide hospital cohort.

Hypothesis: OCI influenced mortality and morbidity of patients with ischemic and hemorrhagic stroke.

Methods: Of the 1369 certified training institutions in Japan, 749 hospitals responded to a questionnaire survey regarding comprehensive stroke care capacities. Among the institutions that responded, data on patients hospitalized between April 1, 2010 and March 31, 2014, because of stroke were obtained from the Japanese Diagnosis Procedure Combination database. In-hospital mortality morbidity was analyzed using hierarchical logistic regression analysis adjusted for age, sex, level of consciousness on admission, Charson Score and the number of OCI fulfilled in each component and in total.

Results: Data from 265 institutions and 220,027 emergency-hospitalized patients were analyzed. Patients fulfilled the criteria for admission to a SCU, stroke team assessment and the presence of rehabilitation were 29.9%, 41.2% and 66.5%, respectively. Mortality adjusted for age, sex, Charson score and level of consciousness was significantly correlated with admission to a SCU (OR=0.83, p<0.001), SCU team assessment (OR=0.84,P<0.001), and rehabilitation (OR=0.36, p=0.031). OCI was significantly associated with decreased mortality (OR=0.45, p<0.001) and the highest OCI score was associated with 89.4% decrease of mortality. (OR=0.104, p<0.001) Modified ranking scale 0 to 2 rate were also associated significantly with SCU admission (p<0.001). These association holds for ischemic stroke and subarachnoid hemorrhage.

Conclusion: A strong association between organized stroke care and lower mortality was apparent. These data suggest that organized stroke care should be provided to stroke patients regardless of stroke subtype.

Consciousness level and off-hour admission affect discharge outcome of acute stroke patients: a J-ASPECT study

Background

Poor outcomes have been reported for stroke patients admitted outside of regular working hours. However, few studies have adjusted for case severity. In this nationwide assessment, we examined relationships between hospital admission time and disabilities at discharge while considering case severity.

Methods and Results

We analyzed 35 685 acute stroke patients admitted to 262 hospitals between April 2010 and May 2011 for ischemic stroke (IS), intracerebral hemorrhage (ICH), or subarachnoid hemorrhage (SAH). The proportion of disabilities/death at discharge as measured by the modified Rankin Scale (mRS) was quantified. We constructed 2 hierarchical logistic regression models to estimate the effect of admission time, one adjusted for age, sex, comorbidities, and number of beds; and the second adjusted for the effect of consciousness levels and the above variables at admission. The percentage of severe disabilities/death at discharge increased for patients admitted outside of regular hours (22.8%, 27.2%, and 28.2% for working‐hour, off‐hour, and nighttime; P<0.001). These tendencies were significant in the bivariate and multivariable models without adjusting for consciousness level. However, the effects of off‐hour or nighttime admissions were negated when adjusted for consciousness levels at admission (adjusted OR, 1.00 and 0.99; 95% CI, 1.00 to 1.13 and 0.89 to 1.10; P=0.067 and 0.851 for off‐hour and nighttime, respectively, versus working‐hour). The same trend was observed when each stroke subtype was stratified.

Conclusions

The well‐known off‐hour effect might be attributed to the severely ill patient population. Thus, sustained stroke care that is sufficient to treat severely ill patients during off‐hours is important.

Excitation-photon-energy selectivity of photoconversions in halogen-bridged Pd-chain compounds: Mott insulator to metal or charge-density-wave state

Ultrafast photoinduced transitions of a one-dimensional Mott insulator into two distinct electronic phases, metal and charge-density-wave (CDW) state, were achieved in a bromine-bridged Pd-chain compound [Pd(en)2Br](C5-Y)2H2O (en=ethylenediamine and C5-Y=dialkylsulfosuccinate), by selecting the photon energy of a femtosecond excitation pulse. For the resonant excitation of the Mott-gap transition, excitonic states are generated and converted to one-dimensional CDW domains. For the higher-energy excitation, free electron and hole carriers are produced, giving rise to a transition of the Mott insulator to a metal. Such selectivity in photoconversions by the choice of initial photoexcited states opens a new possibility for the developments of advanced optical switching and memory functions.

Retinoic acid prevents mesenteric lymph node dendritic cells from inducing IL-13-producing inflammatory Th2 cells

The vitamin A (VA) metabolite retinoic acid (RA) affects the properties of T cells and dendritic cells (DCs). In VA-deficient mice, we observed that mesenteric lymph node (MLN)-DCs induce a distinct inflammatory T helper type 2 (Th2)-cell subset that particularly produces high levels of interleukin (IL)-13 and tumor necrosis factor-α (TNF-α). This subset expressed homing receptors for skin and inflammatory sites, and was mainly induced by B220(-)CD8α(-)CD11b(+)CD103(-) MLN-DCs in an IL-6- and OX40 ligand-dependent manner, whereas RA inhibited this induction. The corresponding MLN-DC subset of VA-sufficient mice induced a similar T-cell subset in the presence of RA receptor antagonists. IL-6 induced this subset differentiation from naive CD4(+) T cells upon activation with antibodies against CD3 and CD28. Transforming growth factor-β inhibited this induction, and reciprocally enhanced Th17 induction. Treatment with an agonistic anti-OX40 antibody and normal MLN-DCs enhanced the induction of general inflammatory Th2 cells. In VA-deficient mice, proximal colon epithelial cells produced TNF-α that may have enhanced OX40 ligand expression in MLN-DCs. The repeated oral administrations of a T cell-dependent antigen primed VA-deficient mice for IL-13-dependent strong immunoglobulin G1 (IgG1) responses and IgE responses that caused skin allergy. These results suggest that RA inhibits allergic responses to oral antigens by preventing MLN-DCs from inducing IL-13-producing inflammatory Th2 cells.

Simulation study of complex action potential conduction in atrioventricular node

The atrioventricular (AV) node, which is located between the atria and ventricles of the heart, acts as important roles in cardiac excitation conduction between the two chambers. Although there are multiple conduction pathways in the AV node, the structure of the AV node has not been clarified. In this study, we constructed a one-dimensional model of the AV node and simulated excitation conduction between the right atrium and the bundle of His via the AV node. We also investigated several characteristics of the AV node: (1) responses of the AV node to high-rate excitation in the right atrium, (2) the AV nodal reentrant beat induced by premature stimulus, and (3) ventricular rate control during atrial fibrillation with various methods. Our simulation results suggest that multiple conduction pathways act as important roles in controlling the ventricular rate. The one-dimensional model constructed in this study may be useful to analyze complex conduction patterns in the AV node.

Feasibility for the enhancement of an online support system for persons with metabolic syndrome, aimed at applications for ischemic heart disease and heart failure

Previously, we developed of an online support system for persons with metabolic syndrome. In this study, we investigated the possibility of enhancing our system for applications in ischemic heart disease (IHD) and heart failure (HF). The main causes of IHD are obesity, hypertension, arteriosclerosis, hyperglycemia and other metabolic disorders. These conditions are related to lifestyle issues, such as diet and exercise. Dietary management becomes more difficult as the patient's condition worsens. We primarily focused on behavior changes. To raise the user's awareness of food intake, we improved a number of functions of the developed system: an entry of the user's lifestyle information, a calculation of the total calorie intake and a reference of food model pictures in 80 kcal standard quantities. IHD encompasses many of the causes of HF. Management tools appropriate for HF are few. We describe the main functions of our system and promote self-management as a requirement for IHD and HF. We expect that the framework of our system is applicable to the management of patients with chronic HF.

Examination of factors that delay the elution of acetaminophen from over-the-counter drugs

The information on the stability of medications is important to secure their quality. There is, however, little information about the stability of medications which assume to be kept by patients and customers. We previously showed that a delay in drug release occurs in some over-the-counter (OTC) drugs following storage in a high temperature, high humidity environment. In this study we prepared model tablet formulations containing an active ingredient and excipients to investigate the cause of this delayed release. The results reveal that delayed release occurs in preparations compounded with acetaminophen (AA) as the active ingredient and erythritol (ET) and crospovidone (CP) as excipients. In addition, ET deliquesces in a high humidity environment, then incorporates other particles during room temperature storage to form an aggregate. SEM observations and micropore distribution measurements conducted on OTC tablets that exhibit delayed release revealed that the number of intraparticle pores decreased after storage under high temperature, high humidity conditions. Thus, the delayed release by these pharmaceutical product formulations may be due to a change in the micropore structure both on the surface and within the particles, thereby decreasing the solvent infiltration pathways leading to the interior of the preparation.

Assessment of the Plasma/Serum IgG Test to Screen for Periodontitis

Chronic periodontitis is a silent infectious disease prevalent worldwide and affects lifestyle-related diseases. Therefore, efficient screening of patients is essential for general health. This study was performed to evaluate prospectively the diagnostic utility of a blood IgG antibody titer test against periodontal pathogens. Oral examination was performed, and IgG titers against periodontal pathogens were measured by ELISA in 1,387 individuals. The cut-off value of the IgG titer was determined in receiver operating characteristic curve analysis, and changes in periodontal clinical parameters and IgG titers by periodontal treatment were evaluated. The relationships between IgG titers and severity of periodontitis were analyzed. The best cut-off value of IgG titer against Porphyromonas gingivalis for screening periodontitis was 1.682. Both clinical parameters and IgG titers decreased significantly under periodontal treatment. IgG titers of periodontitis patients were significantly higher than those of healthy controls, especially in those with sites of probing pocket depth over 4 mm. Multiplied cut-off values were useful to select patients with severe periodontitis. A blood IgG antibody titer test for Porphyromonas gingivalis is useful to screen hitherto chronic periodontitis patients (ClinicalTrials.gov number NCT01658475).

Valproic acid improves the tolerance for the stress in learned helplessness rats

In this study, we investigated whether previously stressed rats with learned helplessness (LH) paradigm could recover from depressive-like behavior four weeks after the exposure, and also whether chronic treatment with valproic acid (VPA) could prevent behavioral despair due to the second stress on days 54 in these animals. Four weeks after induction of LH, we confirmed behavioral remission in the previously stressed rats. Two-way analysis of variance (ANOVA) performed with two factors, pretreatment (LH or Control) and drug (VPA or Saline), revealed a significant main effect of the drug on immobility time in forced swimming test. Post hoc test showed a shorter immobility time in the LH+VPA group than in the LH+Saline group. Immunohistochemical study of synapsin I showed a significant effect of drug by pretreatment interaction on immunoreactivity of synapsin I in the hippocampus: its expression levels in the regions were higher in the LH+VPA group than in the LH+Saline group. These results suggest that VPA could prevent the reappearance of stress-induced depressive-like behaviors in the rats recovering from prior stress, and that the drug-induced presynaptic changes in the expression of synapsin I in the hippocampus of LH animals might be related to improved tolerance toward the stress.

Genetic variants at CDC123/CAMK1D and SPRY2 are associated with susceptibility to type 2 diabetes in the Japanese population

AIMS/HYPOTHESIS

Recently, rs10906115 in CDC123/CAMK1D, rs1359790 near SPRY2, rs1436955 in C2CD4A/C2CD4B and rs10751301 in ODZ4 were identified as genetic risk variants for type 2 diabetes by a genome-wide association study in a Chinese population. The aim of the present study was to ascertain the role of these four variants in conferring susceptibility to type 2 diabetes in the Japanese population.

METHODS

We genotyped 11,530 Japanese individuals (8,552 type 2 diabetes cases, 2,978 controls) for the above single nucleotide polymorphisms (SNPs) and used logistic regression analysis to determine whether they were associated with type 2 diabetes.

RESULTS

In accordance with the findings in a Chinese population, rs10906115 A, rs1359790 C and rs1436955 G were found to be risk alleles. Both rs10906115 and rs1359790 were significantly associated with susceptibility to type 2 diabetes in our study (rs10906115 OR 1.15, 95% CI 1.08, 1.22; p = 6.10 × 10(-6); rs1359790 OR 1.14, 95% CI 1.06, 1.21; p = 2.24 × 10(-4)). Adjustment for age, sex and BMI had no significant effects on the association between these variants and the disease. We did not observe any significant associations between the SNPs and any metabolic traits, e.g. BMI, fasting plasma glucose (determined for 1,332 controls), HOMA of beta cell function (900 controls) and HOMA of insulin resistance (900 controls; p > 0.05).

CONCLUSIONS/INTERPRETATION

The SNPs rs10906115 A and rs1359790 C are significantly associated with susceptibility to type 2 diabetes in the Japanese population, confirming that these alleles are common susceptibility variants for type 2 diabetes in East Asian populations.

Influence of leukotriene pathway polymorphisms on clinical responses to montelukast in Japanese patients with asthma

WHAT IS KNOWN AND OBJECTIVE

Montelukast, a cysteinyl leukotriene receptor 1 antagonist, is safe and efficacious in patients with asthma. The mechanisms underlying the significant interpatient variability in response to montelukast are not clear but are believed to be, in part, because of genetic variability.

METHODS

To examine the associations between polymorphisms in candidate genes in the leukotriene pathway and outcomes in patients with asthma on montelukast for 4-8 weeks, we evaluated the changes in peak expiratory flow (PEF), forced expiratory volume in 1 s (FEV(1·0) ) and patients' subjective symptom before and after montelukast treatment. DNA was collected from 252 Japanese participants.

RESULTS AND DISCUSSION

Two single-nucleotide polymorphisms (SNPs) in the ALOX5 (rs2115819) and LTA4H (rs2660845) genes were successfully typed. There was no difference between members of the general population (n = 200) and patients (n = 52) in each genotype frequency. Significant associations were found between SNP genotypes in the LTA4H gene and changes in PEF and FEV(1·0) . The PEF and FEV(1·0) responses to montelukast in the A/A genotypes (n = 4) for the LTA4H SNP were significantly higher than those in the G allele carriers (A/G+G/G) (n = 17).

WHAT IS NEW AND CONCLUSION

Despite the small sample size, our results suggest that genetic variation in leukotriene pathway candidate genes contributes to variability in clinical responses to montelukast in Japanese patients with asthma.

Comparison of physical properties and drug-releasing characteristics of white petrolatums

White petrolatums of Japanese Pharmacopoeia grade and Sun white marketed as a cosmetic were characterized by measuring their physical properties and drug-releasing characteristics. White petrolatums of Japanese Pharmacopoeia grade available commercially in Japan were Perfecta, White 1S, Ultima, Snow, Snow V and Regent (Propeto). Penetrating stress, shear stress and spreading properties were measured as physical properties of the white petrolatums. The physical properties of white petrolatums varied, and Regent was the softest and the most spreadable ointment base. In vitro release test was performed using flow-through Franz diffusion cells. Fluorescein isothiocyanate and tetracycline hydrochloride were used as drug models. Their release characteristics varied among the tested white petrolatums, and Regent had the best release properties. Among the white petrolatums, with the exception of Regent, the release properties should depend on the distribution of drugs between white petrolatum and the receiver solution. Considerations of usability and characteristics of theprincipal agent are needed when choosing white petrolatums.

A cyclic peptide targeted against PSD-95 blocks central sensitization and attenuates thermal hyperalgesia

Post-synaptic density protein PSD-95 is emerging as a valid target for modulating nociception in animal studies. Based on the key role of PSD-95 in neuronal plasticity and the maintenance of pain behavior, we predicted that CN2097, a peptide-based macrocycle of nine residues that binds to the PSD-95 Discs large, Zona occludens 1 (PDZ) domains of PSD-95, would interfere with physiologic phenomena in the spinal cord related to central sensitization. Furthermore, we tested whether spinal intrathecal injection of CN2097 attenuates thermal hyperalgesia in a rat model of sciatic neuropathy. Results demonstrate that spinal CN2097 reverses hyperexcitability of wide dynamic range (WDR) neurons in the dorsal horn of neuropathic rats and decreases their evoked responses to peripheral stimuli (brush, low caliber von Frey and pressure), whereas CN5125 ("negative control") has no effect. CN2097 also blocks C-fiber long-term potentiation (LTP) in the dorsal horn, which is linked to neuronal plasticity and central sensitization. At a molecular level, CN2097 attenuates the increase in phosphorylated p38 MAPK, a key intracellular signaling pathway in neuropathic pain. Moreover, spinal injection of CN2097 blocks thermal hyperalgesia in neuropathic rats. We conclude that CN2097 is a small molecule peptide with putative anti-nociceptive effects that modulates physiologic phenomena related to central sensitization under conditions of chronic pain.

Effectiveness of mechanochemical treatment with cyclodextrins on increasing solubility of glimepiride

We investigated the enhancement of the solubility of glimepiride (GLM), a poorly water soluble anti-diabetes drug, by cogrinding it with various cyclodextrins (CDs) using a ball mill. The phase solubility profiles of GLM with beta-CD and its derivatives were classified as A(L)-type, indicating the formation of a 1 : 1 stoichiometric water-soluble complex. When GLM crystals were coground with beta-CD using a ball mill for 48 h, the aqueous solubility of GLM increased to approximately 250 microg/mL. The powder X-ray diffraction pattern showed that the peak intensity of crystalline GLM decreased after cogrinding. Endothermic peaks of around 208 degrees C, which were assigned to the fusion of GLM crystals, disappeared in the DSC measurement of the ground mixture. After cogrinding, two sharp peaks assigned to sulfonylurea and benzoyl carbonyl stretching bands varied to broaden the peak to around 1700 cm(-1) in the C=O stretching region. These results suggested the formation of a complex between GLM and beta-CD during cogrinding.

Correlation between Magnetic Resonance Imaging Findings and Pathological Observations in Tumefactive Multiple Sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. Tumefactive MS (TMS) is a subtype of MS characterized by solitary or multiple mass lesions with open-ring enhancement on brain magnetic resonance imaging (MRI). Three TMS cases, diagnosed histopathologically by brain biopsy, that were difficult to distinguish from brain tumors or brain abscesses on MRI are presented. On T2-weighted imaging (T2WI) the lesions were high intensity in the center and periphery, with open-ring contrast enhancement at the periphery; iso- to low intensity areas (“T2 low rim”) were seen in the surrounding region. Histopathological examination revealed the characteristic features of TMS: severe central demyelination and focal necrosis, peripheral neovascularization and perivascular inflammatory cell infiltration, and perifocal edema. On immunochemistry, both the endothelial cells of the neovasculature and the surrounding macrophages in the periphery expressed vascular endothelial growth factor and monocyte chemoattractant protein-1, which mediate inflammation and angioneogenesis and increase vascular permeability. These findings correspond to the T2 low rim co-localizing with the site of gadolinium enhancement on MRI. Thus, the present study clearly demonstrates the correlation between the radiological features and the pathophysiological aspects of TMS, which may contribute to more precise diagnosis of TMS.