Single-Cell RNA Sequencing Reveals an Immune Landscape of CD4+ T Cells in Coronary Culprit Plaques With Acute Coronary Syndrome in Humans-Brief Report.

BACKGROUND: Acute coronary syndrome (ACS) involves plaque-related thrombosis, causing primary ischemic cardiomyopathy or lethal arrhythmia. We previously demonstrated a unique immune landscape of myeloid cells in the culprit plaques causing ACS by using single-cell RNA sequencing. Here, we aimed to characterize T cells in a single-cell level, assess clonal expansion of T cells, and find a therapeutic target to prevent ACS. METHODS: We obtained the culprit lesion plaques from 4 patients with chronic coronary syndrome (chronic coronary syndrome plaques) and the culprit lesion plaques from 3 patients with ACS (ACS plaques) who were candidates for percutaneous coronary intervention with directional coronary atherectomy. Live CD45+ immune cells were sorted from each pooled plaque samples and applied to the 10× platform for single-cell RNA sequencing analysis. We also extracted RNA from other 3 ACS plaque samples and conducted unbiased TCR (T-cell receptor) repertoire analysis. RESULTS: CD4+ T cells were divided into 5 distinct clusters: effector, naive, cytotoxic, CCR7+ (C-C chemokine receptor type 7) central memory, and FOXP3 (forkhead box P3)+ regulatory CD4+ T cells. The proportion of central memory CD4+ T cells was higher in the ACS plaques. Correspondingly, dendritic cells also tended to express more HLAs (human leukocyte antigens) and costimulatory molecules in the ACS plaques. The velocity analysis suggested the differentiation flow from central memory CD4+ T cells into effector CD4+ T cells and that from naive CD4+ T cells into central memory CD4+ T cells in the ACS plaques, which were not observed in the chronic coronary syndrome plaques. The bulk repertoire analysis revealed clonal expansion of TCRs in each patient with ACS and suggested that several peptides in the ACS plaques work as antigens and induced clonal expansion of CD4+ T cells. CONCLUSIONS: For the first time, we revealed single cell-level characteristics of CD4+ T cells in patients with ACS. CD4+ T cells could be therapeutic targets of ACS. REGISTRATION: URL: https://upload.umin.ac.jp/cgi-open-bin/icdr_e/ctr_view.cgi?recptno=R000046521; Unique identifier: UMIN000040747.

Discovery of presumably introduced spiders, Oedignathascrobiculata Thorell, 1881 (Araneae, Liocranidae) and Boagriusqiong Lin & Li, 2022 (Araneae, Palpimanidae) on Chichi-jima Island, the Ogasawara Islands, Japan.

Background: The spider fauna of the Ogasawara Islands, oceanic islands located 1,000 km south of mainland Japan was comprehensively examined by the National Museum of Nature and Science in 2011, which revealed that approximately 70% of the spider fauna was composed of non-native species. Following the preceding study, however, only descriptions of several new species have been added and no major updates have been made for the overall spider fauna of the Islands. New information: The faunistic survey of spiders conducted on Chichi-jima Island, the largest island in the Ogasawara Islands in 2023 revealed the presence of two ground-dwelling spider species, Oedignathascrobiculata Thorell, 1881 (Araneae, Liocranidae) and Boagriusqiong Lin & Li, 2022 (Araneae, Palpimanidae) on the Island. This represents the first record of the two species from Japan, the first record of palpimaid spiders from Japan and the initial documentation of liocranid spiders in the Ogasawara Islands.

Gene Polymorphisms of NLRP3 Associated With Plasma Levels of 4ß-Hydroxycholesterol, an Endogenous Marker of CYP3A Activity, in Patients With Asthma.

Inflammation decreases the activity of cytochrome P450 3A (CYP3A). Nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) is responsible for regulating the inflammatory response, and its genetic polymorphisms have been linked to inflammatory diseases such as asthma. However, there have been few studies on the effect of NLRP3 on CYP3A activity. We aimed to investigate the association between polymorphisms in the NLRP3 gene and plasma 4ß-hydroxycholesterol (4ßOHC), an endogenous marker of CYP3A activity, in patients with asthma. In this observational study including 152 adult asthma patients, we analyzed 10 NLRP3 gene single-nucleotide polymorphisms (SNPs). Plasma 4ßOHC levels were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results showed that five SNPs were associated with significantly lower plasma 4ßOHC concentrations. Among these SNPs, rs3806265, rs4612666, rs1539019, and rs10733112 contributed to a significant increase in plasma IL-6 concentrations. Moreover, a multivariate regression model showed that the rs3806265 TT, rs4612666 CC, rs1539019 AA, and rs10733112 TT genotypes were significant factors for decreased plasma 4ßOHC, even after including patient background factors and CYP3A5*3 (rs776746) gene polymorphisms as covariates. These results were also observed when plasma 4ßOHC concentrations were corrected for cholesterol levels. We conclude that NLRP3 gene polymorphisms are involved in increasing plasma IL-6 concentrations and decreasing plasma 4ßOHC concentrations in patients with asthma. Therefore, NLRP3 gene polymorphisms may be a predictive marker of CYP3A activity in inflammatory diseases such as asthma.

ID3 is a novel target gene of p53 and modulates lung cancer cell metastasis.

The tumor suppressor p53 prevents cancer development by regulating dozens of target genes with diverse biological functions. Although numerous p53 target genes have been identified to date, the dynamics and function of the regulatory network centered on p53 have not yet been fully elucidated. We herein identified inhibitor of DNA-binding/differentiation-3 (ID3) as a direct p53 target gene. p53 bound the distal promoter of ID3 and positively regulated its transcription. ID3 expression was significantly decreased in clinical lung cancer tissues, and was closely associated with overall survival outcomes in these patients. Functionally, ID3 deficiency promoted the metastatic ability of lung cancer cells through its effects on the transcriptional regulation of CDH1. Furthermore, the ectopic expression of ID3 in p53-knockdown cells restored E-cadherin expression. Collectively, the present results demonstrate that ID3 plays a tumor-suppressive role as a downstream effector of p53 and impedes lung cancer cell metastasis by regulating E-cadherin expression.

Global cognition and executive functions of older adults with type 1 diabetes mellitus without dementia.

AIMS/INTRODUCTION: This study aimed to characterize the global cognition and executive functions of older adults with type 1 diabetes mellitus in comparison with type 2 diabetes mellitus. MATERIALS AND METHODS: This study included 37 patients with type 1 diabetes mellitus aged ≥65 years and 37 age- and sex-matched patients with type 2 diabetes mellitus. Patients with dementia scoring <24 on the Mini-Mental State Examination were excluded. General cognition, memory, classic, and practical executive function were investigated. RESULTS: Patients with type 1 diabetes mellitus demonstrated lower psychomotor speed scores on Trail Making Tests A and B (P < 0.001, P < 0.013) than those with type 2 diabetes mellitus. The dysexecutive syndrome behavioral assessment revealed similar results in patients with types 1 and 2 diabetes mellitus. The Wechsler Memory Scale-Revised verbal episodic memory and Montreal Cognitive Assessment Japanese version were similar in terms of general cognition, but worse delayed recall subset on the latter was associated with type 2 diabetes mellitus (P = 0.038). A worse Trail Making Test-A performance was associated with type 1 diabetes mellitus and age (P < 0.004, P < 0.029). CONCLUSIONS: Executive function of psychomotor speed was worse in older outpatient adults without dementia with type 1 diabetes mellitus than in those with type 2 diabetes mellitus but with no significant differences in the comprehensive and practical behavioral assessment of dysexecutive syndrome. Patients with type 1 diabetes had more severely impaired executive function, whereas those with type 2 had greater impaired memory than executive function.

Differentiating localized autoimmune pancreatitis and pancreatic ductal adenocarcinoma using endoscopic ultrasound images with deep learning.

Objectives: Localized autoimmune pancreatitis is difficult to differentiate from pancreatic ductal adenocarcinoma on endoscopic ultrasound images. In recent years, deep learning methods have improved the diagnosis of diseases. Hence, we developed a special cross-validation framework to search for effective methodologies of deep learning in distinguishing autoimmune pancreatitis from pancreatic ductal adenocarcinoma on endoscopic ultrasound images. Methods: Data from 24 patients diagnosed with localized autoimmune pancreatitis (8751 images) and 61 patients diagnosed with pancreatic ductal adenocarcinoma (20,584 images) were collected from 2016 to 2022. We applied transfer learning to a convolutional neural network called ResNet152, together with our innovative imaging method contributing to data augmentation and temporal data process. We divided patients into five groups according to different factors for 5-fold cross-validation, where the ordered and balanced datasets were created for the performance evaluations. Results: ResNet152 surpassed the endoscopists in all evaluation metrics with almost all datasets. Interestingly, when the dataset is balanced according to the factor of the endoscopists' diagnostic accuracy, the area under the receiver operating characteristic curve and accuracy were highest at 0.85 and 0.80, respectively. Conclusions: It is deduced that image features useful for ResNet152 correlate with those used by endoscopists for their diagnoses. This finding may contribute to sample-efficient dataset preparation to train convolutional neural networks for endoscopic ultrasonography-imaging diagnosis.

Measurement of luteinizing hormone surge in vaginal discharge: a potential biomarker that enables simple, non-invasive prediction of the periovulatory period.

BACKGROUND: Predicting the periovulatory period is very important for conception. Current approaches to predicting the periovulatory period include monitoring of basal body temperature and urine luteinizing hormone (LH) concentration; however, these methods are time-consuming. Here, we examined the potential of using vaginal discharge (VD) as a non-invasive means of sample collection for determining the LH surge that indicates ovulation. METHODS: Urine and VD samples were collected from 35 healthy women aged 20-39 years. VD samples were collected with panty liners to reduce the burden on participants. Daily first urine samples and used panty liners were collected from the 10th through 19th days of the menstrual cycle. Urine and VD LH (uLH and vLH) levels in the samples were measured by enzyme-linked immunosorbent assay. Measured vLH baseline and first surge values were analyzed using Student's t-test and ROC curves. RESULTS: Samples for a total of 55 menstrual cycles were collected. We used uLH surge to establish the date of ovulation. uLH surges were observed in 49 cycles, 34 of which had corresponding VD samples that qualified for measurement. Five cycles were excluded due to a lack of vLH data. In the remaining 29 cycles, the vLH surge appeared within the fertile window 90% of the time, and the sensitivity and specificity of the test were 86% and 83%, respectively. CONCLUSIONS: VD has potential for use as a sample for predicting the periovulatory period by measuring LH content.

Effects of mitral valve repair on valvular geometry and hemodynamics in dogs with myxomatous mitral valve disease.

OBJECTIVE: To investigate the effects of mitral valve repair on the geometry of the mitral valve complex, hemodynamics, and cardiac function of dogs with myxomatous mitral valve disease (MMVD). STUDY DESIGN: Retrospective cohort study. SAMPLE POPULATION: Dogs (n = 77) with stage C MMVD undergoing mitral valve repair under cardiopulmonary bypass. METHODS: Mitral valve geometry and cardiac function were assessed using echocardiography preoperatively, 1 week postoperatively and 3 months postoperatively. RESULTS: The coaptation length (0 [0-0] vs. 7 [6-8.5] mm, p < .001) and forward stroke volume index (1.5 ± 0.4 vs. 2.3 ± 0.6 mL/kg, p < .001) were higher at 3-months postoperatively than preoperatively, whereas the vertebral heart score (12.3 ± 1.2 vs. 10.8 ± 0.8 V, p < .001), left atrial-to-aortic ratio (2.2 ± 0.7 vs. 1.2 ± 0.3, p < .001), peak velocity of early diastolic transmitral flow (144 ± 34 vs. 91 ± 18 cm/s, p < .001), and regurgitant volume index (11.3 [8.2-14.0] vs. 1.6 [0.95-2.35] mL/kg, p < .001) were lower. Postoperatively, mitral valve geometry was completely changed within 1 week, whereas changes in vertebral heart score lasted for 3 months. CONCLUSION: Mitral valve repair changed valvular geometry and improved hemodynamics as assessed by follow-up echocardiography. CLINICAL SIGNIFICANCE: This study acts as reference for surgeons and cardiologists considering or evaluating the effects of mitral valve repair in dogs and provides useful data for the enhancement of relevant surgical techniques and the selection of relevant pre- and postoperative observations.

Paraneoplastic Cerebellar Degeneration Accompanied by Seropositivity for Anti-GAD65, Anti-SOX-1 and Anti-VGCC Antibodies Due to Small-cell Lung Cancer.

Paraneoplastic cerebellar degeneration (PCD) is a paraneoplastic neurological syndrome that is rarely accompanied by seropositivity with a combination of multiple antibodies. We herein report a 50-year-old man with PCD accompanied by small-cell lung cancer (SCLC). This patient was seropositive for anti-glutamic acid decarboxylase 65, anti-SRY-related HMG-box gene 1 and anti-voltage-gated calcium channel antibodies. After chemoradiation therapy without immunotherapy, cerebellar ataxia of the trunk and limbs markedly improved, along with a notable amelioration of SCLC. This case suggests that tumor therapy should be started immediately and that a panel of anti-neuronal antibodies should be evaluated when PCD with SCLC is suspected.

Telehealth Follow-up Using a Real-Time Electrocardiogram Device Improves Electrocardiogram Monitoring Duration and Patient Satisfaction After Catheter Ablation.

Background: There is a strong demand for remote monitoring systems to gather health data. This study investigated the safety, usefulness, and patient satisfaction in outpatient care using telehealth with real-time electrocardiogram (ECG) monitoring after catheter ablation. Methods and Results: In all, 38 patients who underwent catheter ablation were followed up using telehealth. At the 3- and 6-month follow-up, a self-fitted Duranta ECG monitoring device was sent to the patient's home before the online consultation. Patients attached the devices themselves, and the doctors viewed the patients by video chat and performed real-time ECG monitoring. The frequency of hospital visits and the ECG monitoring duration were compared with conventional in-person follow-up data (n=102). The completion rate for telehealth follow-up was 32 of 38 patients (84%). The number of hospital visits during the 6 months was significantly lower with telehealth follow-up than with conventional follow-up (median [interquartile range] 1 [1-1] vs. 5 [3-5]; P<0.0001). However, the ECG monitoring duration was approximately 4-fold longer for the telehealth follow-up (median [interquartile range] 89 [64-117] vs. 24 [0.1-24] h; P<0.0001). No major adverse events were observed during the telehealth follow-up. Patient surveys showed high satisfaction with telehealth follow-up due to reduced hospital visits. Conclusions: A combination of telehealth follow-up with real-time ECG monitoring increased the ECG monitoring duration and patient satisfaction without any adverse events.

Retrospective observational study of changes in serum cytokines and adiponectin with continuous plasma exchange with dialysis therapy for severe COVID-19.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is associated with a marked increase in the inflammatory cytokines, IL-6 and IL-18. Blood purification therapy aimed at controlling cytokines is one treatment option; however, evidence of its effectiveness is needed. Plasma exchange with dialysis (PED) is a blood purification method involving selective plasma exchange with dialysate flowing through the outer hollow fiber of the plasma separator. In this retrospective study, we investigated the efficacy of continuous PED (cPED) over 48 h in five patients with severe COVID-19. METHODS: We assessed changes in IL-6 and IL-18, as well as adiponectin (APN). RESULTS: There were no significant differences in changes in IL-6 and IL-18, but there was a marked improvement in cases with abnormally high IL-6 and IL-18 levels at baseline. APN, which inhibits inflammatory cytokines, was significantly elevated post-cPED. CONCLUSION: Our results suggest that cPED therapy is an effective treatment for COVID-19.

The relationship between the incision line and position of the latissimus dorsi muscle for subcutaneous implantable cardioverter-defibrillator intermuscular implantations.

INTRODUCTION: Intermuscular implantations of subcutaneous implantable cardioverter-defibrillators (S-ICD) have been recommended, but the position of the anterior border of the latissimus dorsi muscle (LDM) has not previously been evaluated in establishing an incision line to facilitate the intermuscular approach. The objective of this study is to evalua the position and trend of the anterior border of the LDM in patients who are candidates for implantable cardioverter-defibrillators. METHODS: The distance from the back to the anterior border of the LDM (A) and the anterior-posterior width of the chest wall (B) were measured on computed tomography retrospectively, and the ratio (=A/B) was used as the position of the anterior border of the LDM. In addition, the variability and factors affecting the values were evaluated. RESULTS: An analysis was performed on 78 patients, and the position of the anterior border of the LDM (=A/B) exhibited a normal distribution, with a mean value of 0.53 ± 0.062 (0.41-0.69). The position of the anterior border of the LDM tended to be more anterior in younger, taller, male, primary prevention, nonheart failure, low brain natriuretic peptide level, and nondiabetic patients. CONCLUSION: The position of the anterior border of the LDM varied from case to case with variable results. Conventional incisions on the midaxillary line may be inappropriate for intermuscular implantations, and the position of the anterior border of the LDM should be evaluated in each individual case to establish the incision line.

A Case with Anti-ganglioside Antibodies Showing Multiple Cranial Nerve Palsies Detected on Gadolinium-enhanced Magnetic Resonance Imaging.

The anti-GQ1b IgG antibody is often accompanied by other anti-ganglioside antibodies, which induces various neurological symptoms. We herein report a patient with anti-ganglioside antibodies, including anti-GQ1b IgG and anti-GT1a IgG antibodies, showing bilateral ophthalmoplegia, facial nerve palsies, dysarthria, dysphagia, dysesthesia in both hands, and enhancement of the bilateral oculomotor, abducens, and facial nerves on gadolinium (Gd)-enhanced T1-weighted brain magnetic resonance imaging (MRI). He was first treated with intravenous immunoglobulin, which improved ophthalmoplegia, bulbar palsies, and dysesthesia of hands, but the facial nerve palsies worsened, and Gd enhancement of the brain nerves persisted. High-dose methylprednisolone therapy subsequently improved the facial nerve palsies and Gd enhancement of the cranial nerves. This is the first case with anti-ganglioside antibodies presenting with multiple cranial nerve palsies that was followed to track the changes in the Gd enhancement of cranial nerves on MRI.

Assessing fluid volume and determining outcomes of acute heart failure using plasma human atrial natriuretic peptide.

BACKGROUND: The post-dialysis plasma level of human atrial natriuretic peptide (hANP) reflects the fluid volume in patients on hemodialysis. The threshold hANP level is reportedly 100 pg/mL; however, the clinical usefulness of the threshold hANP level for volume control has not been sufficiently studied. METHODS: We conducted a single-center, retrospective, observational study that included 156 hemodialysis patients without atrial fibrillation. First, we examined the usefulness of the threshold hANP level (100 pg/mL) for predicting hypoxemia due to congestion in a short-term observational study from December 30, 2015 to January 5, 2016. Subsequently, we conducted a 5-year follow-up study wherein the outcomes were hospitalization due to acute heart failure (AHF), development of cardiovascular diseases (CVD), and all-cause death. Finally, we collected echocardiography data to investigate the relationship between cardiac function and hANP. RESULTS: Our short-term observational study showed that patients with an hANP level ≥ 100 pg/mL developed hypoxemia due to congestion (odds ratio, 3.52; 95% confidence interval, 1.06-11.71; P = 0.040). At the 5-year follow-up, patients with an hANP level ≥ 100 pg/mL had significantly higher rates of hospitalization due to AHF, CVD, and all-cause death based on the log-rank test (P = 0.003, P = 0.019, P < 0.001, respectively). Cardiac disfunctions were significantly associated with the high hANP level. CONCLUSIONS: The hANP level is indicative of both fluid volume and cardiac dysfunction. A threshold hANP level of 100 pg/mL can serve as a predictive marker for AHF and a practical indicator for volume control.

Predictors of recurrence in patients without non-inducibility of ventricular tachycardia at the end of ablation.

Background: Ventricular tachycardia (VT) non-inducibility at the end of ablation is associated with a less likely VT recurrence. However, it is not clear whether we should use VT non-inducibility as a routine end point of VT ablation. The aim of this study was to evaluate VT recurrence in patients in whom VT non-inducibility was not achieved at the end of the radiofrequency (RF) ablation and the factors attributing to the VT recurrence. Methods: We analyzed that 62 patients in whom VT non-inducibility was not achieved at the end of the RF ablation were studied. Results: Over 2 years, 22 (35%) of the cases had VT recurrences. A multivariate analysis showed that an LVEF ≥35% (HR: 0.19; 95% CI: 0.06-0.49; p < .01) and elimination of the clinical VT as an acute ablation efficacy (HR: 0.23; 95% CI: 0.04-0.81; p = .02) were independent predictors of fewer VT recurrences. RF ablation was associated with a 91.1% reduction in VT episodes. Conclusion: Even if VT non-inducibility was not achieved, patients with an LVEF ≥35% or in whom the clinical VT could be eliminated might be prevented from having VT recurrences. The validity of the VT non-inducibility of any VT should be evaluated considering each patient's background and the results of the procedure.

The impact of the procedural parameters on the lesion characteristics associated with AF recurrence: Late-gadolinium enhancement magnetic resonance imaging (LGE-MRI) analysis.

BACKGROUND: Lesion gaps assessed by late-gadolinium enhancement magnetic resonance imaging (LGE-MRI) are associated with the atrial fibrillation (AF) recurrence after pulmonary vein isolation. Animal studies have demonstrated that the catheter-contact force (CF), stability, and orientation are strongly associated with lesion formation. However, the impact of those procedural factors on the lesion characteristics associated with AF recurrence has not been well discussed. METHODS: A total of 30 patients with paroxysmal AF who underwent catheter ablation were retrospectively enrolled. Radiofrequency (RF) applications were performed with 35 W for 30 s in a point-by-point fashion under esophageal temperature monitoring. The inter-lesion distance was 4 mm. The lesions were visualized by LGE-MRI 3 months postprocedure and assessed by the LGE volume (ml), gap number (GN), and average gap length (AGL [mm]). The gaps were defined as nonenhancement sites of >4 mm. The procedural factors including the catheter-CF, stability, and orientation were calculated on the NavX system. RESULTS: Six (20%) of 30 patients had AF recurrences 12 months postablation. A univariate analysis demonstrated that the AGL was associated with AF recurrence (hazard ratio [HR]: 1.20, confidence interval [CI]: 1.03-1.42, p = .02). All AF recurrence were found in patients with an AGL of >7 mm. The catheter-CF and stability were associated with an AGL of >7 mm, but not the orientation (CF-HR: 0.62, CI: 0.39-0.97, p = .038; stability-HR: 0.8, CI: 0.66-0.98, p = .027). CONCLUSIONS: RF ablation with a low CF and poor catheter stability has a potential risk of creating large lesion gaps associated with AF recurrence.

Trans-jugular vein approach for ablation of ventricular premature contractions originating from the tricuspid annulus.

A young-male underwent radiofrequency (RF) ablation of ventricular premature contractions (VPCs) of over 30,000/day and the morphology exhibited left bundle branch block and a superior axis, which indicated the VPCs originated from the inferior portion of the right ventricle (RV). While the PENTARAY catheter was placed under the tricuspid valve (TV), the earliest potential, which preceded the QRS onset by 34 ms, was recorded. Pace mapping there presented a very similar QRS morphology to the target VPC. However, the radiofrequency (RF)-catheter could not be placed under the TV even when a deflectable sheath was used, because the deflectable curve of the RF-catheter was larger than that of the PENTARAY. An over-the-vale RF application was not effective, so the trans-jugular approach with a deflectable sheath was indicated. The tip of the sheath was placed at a higher portion of the RV cavity to maintain an adequate distance for the RF-catheter tip to be deflected and placed under the TV. With this maneuver, the tip of the RF-catheter was successfully placed under the TV, which was confirmed by intracardiac ultrasound. Small atrial potentials and larger ventricular potentials could be recorded from the distal tip of the RF-catheter, which might indicate that the tip was placed at the TV annulus. An RF application at that site permanently abolished the VPC. Placing the tip of the RF-catheter under the TV by the femoral approach is very difficult in some cases. The trans-jugular approach with a deflectable sheath is one option for arrhythmias from the TV.

Revision of goblin spiders (Araneae: Oonopidae) in the Nansei Islands, Southwest Japan, with description of a new species.

We revised the fauna of goblin spiders (Oonopidae) in the Nansei Islands, southwest Japan, and recognized 12 species of seven genera. Eleven of them were described species, namely, Gamasomorpha cataphracta Karsch, 1881, Heteroonops spinimanus (Simon, 1892), Ischnothyreus narutomii (Nakatsudi, 1942), Ischnothyreus peltifer (Simon, 1891), Ischnothyreus velox Jackson, 1908, Opopaea cornuta Yin & Wang, 1984, Opopaea deserticola Simon, 1892, Opopaea syarakui (Komatsu, 1967), Orchestina flava Ono, 2005, Xestaspis parmata (Thorell, 1890), and Xyphinus karschi (Bsenberg & Strand, 1906). A new species is described under the name of Ischnothyreus ogatai sp. nov. This paper provides photographs of each oonopid species, notes on habitat and distribution, and keys to the species. A detailed description of I. ogatai sp. nov. (for both sexes), morphological data regarding three species newly added to the Japanese fauna (X. parmata, I. velox, and O. cornata), and additional data on the genital morphology of G. cataphracta are also presented.

The ontogenetic dietary shift from non-dangerous to dangerous prey in predator-eating predators under capture risk.

Evaluating the patterns and generality of ontogenetic dietary shifts (ODSs) contributes to understanding prey-predator interactions and food web dynamics. Numerous studies have focused on predators that target distinctively lower trophic-level organisms. However, the ODS of predators that routinely prey on organisms at similar trophic levels (i.e., predator-eating predators) have been neglected in ODS research. The ODS patterns of predator eaters may not fit into conventional frameworks owing to constraints of potential capture risk (e.g., deadly counterattack from prey) and body size. We aimed to reveal the ODS patterns of predator eaters and determine whether the patterns were affected by body size and capture risk. Assuming that capture risk is a significant factor in ODS patterns, we expected: (1) juvenile araneophagic spiders to forage on non-dangerous prey (insects) and capture larger non-dangerous prey more frequently than dangerous prey (spiders); and (2) as they grow, their prey types will shift from non-dangerous to dangerous prey because larger predators will be able to capture dangerous prey as the optimal food. As a result of field observations, we revealed that the major ODS pattern in these spiders changed from a mixed (both insect and spider) to a spider-dominant diet. The model selection approach showed that this diet shift was partly due to predator size, and the relative importance of predator size was higher than the life stage per se and almost equal to species identity. In these spiders, the body size of spider prey tended to be smaller than that of insects when the predators were small, suggesting that capture risk may be a critical factor in determining the ODS patterns of these predators. Therefore, our study adds to the evidence that the capture risk is crucial in comprehensively understanding the mechanisms determining ODS patterns in natural systems.