Clinicopathologic Features of Adult-onset Still's Disease Complicated by Severe Liver Injury.

Adult-onset Still's disease (AOSD) is a systemic inflammatory disorder. Severe liver injury has rarely been reported, although liver enzyme elevation is a common complication of AOSD. We herein report four cases of relapsed AOSD with severe liver disorder by tapering or terminating corticosteroids. Liver specimens revealed robust infiltration of inflammatory cells throughout the lobule, especially cluster of differentiation (CD) 8-positive cells. Relapsed AOSD was refractory to corticosteroid reintroduction and required immunosuppressants. Severe liver injury with AOSD is pathologically characterized by extensive lobular infiltration of CD8-positive cells, and we should consider additive immunosuppressive agents on corticosteroids for treatment.

Acute kidney injury is an unfavorable prognostic factor in acute liver failure and is associated with tumor necrosis factor-alpha.

Acute kidney injury (AKI) is a common complication of acute liver failure (ALF); but its pathogenesis is unknown. ALF was divided into 2 subgroups; ALF with hepatic coma, which corresponds to ALF in the US and Europe, and ALF without hepatic coma. AKI has been shown to worsen the prognosis of ALF patients with hepatic coma; however, its prognostic significance in ALF without hepatic coma remains unknown. A single-center retrospective study of 174 patients with ALF was performed. AKI was defined according to KDIGO criteria. AKI developed in 29 (66.0%) of 44 ALF patients with hepatic coma and 27 (38.5%) of 130 ALF patients without hepatic coma. Systemic inflammatory response syndrome (SIRS) was found to be significantly associated with AKI incidence in ALF patients (P < .001). Tumor necrosis factor-alpha (TNF-α) was found to be significantly associated with the presence and severity of AKI (P = .0039 and P = .0140, respectively). On multivariate analysis, TNF-α was an independent risk factor linked with AKI (P = .0103). Even in the absence of hepatic coma, the transplant-free survival rate of ALF was significantly associated with the presence and severity of AKI. Even when hepatic coma is absent, AKI complicated in ALF is strongly associated with TNF-α and worsens the transplant-free survival rate. Before the onset of hepatic coma, plasma exchange, or extracorporeal blood purification to remove inflammatory cytokines should be considered in ALF patients.

Incidence of Mid-Term Prognostic Events in Patients With Acute Coronary Syndrome During the Late 2010s in 2 Tertiary Hospitals in a Rural Area of Japan　- A Temporal Comparison.

Background: Data on the incidence of mid-term prognostic events in patients who developed acute coronary syndrome (ACS) in the late 2010s are scarce. Methods and Results: We retrospectively included and collected data for 889 patients with ACS (ST-elevation myocardial infarction [STEMI]/non-ST-elevation ACS [NSTE-ACS]) discharged alive from 2 tertiary hospitals in Izumo City, in rural Japan, between August 2009 and July 2018. Patients were divided into 3 time groups (T1: August 2009-July 2012; T2: August 2012-July 2015; T3: August 2015-July 2018). The cumulative incidence of major adverse cardiovascular events (MACE; comprising all-cause death, recurrent ACS, and stroke), major bleeding, and heart failure hospitalization within 2 years of discharge was compared among the 3 groups. The incidence of freedom from MACE was significantly higher in the T3 group than in the T1 and T2 groups (93 [95% confidence interval {CI} 90-96%] vs. 86% [95% CI 83-90] and 89% [95% CI 90-96], respectively; P=0.03). There was a tendency for a higher incidence of STEMI among patients in T3 (P=0.057). The incidence of NSTE-ACS was comparable among the 3 groups (P=0.31), as was the incidence of major bleeding and hospitalization for heart failure. Conclusions: The incidence of mid-term MACE in patients who developed ACS during the late 2010 s (2015-2018) was lower than that in prior periods (2009-2015).

Transcatheter arterial steroid injection therapy improves the prognosis of patients with acute liver failure.

Acute liver failure (ALF) is a disorder defined by coagulopathy and encephalopathy with a poor prognosis. No effective therapies have been established except for liver transplantation. We previously reported a subgroup of patients with acute liver injury who developed microcirculatory disturbance. We also established and reported transcatheter arterial steroid injection therapy (TASIT) as a new treatment of ALF. Here, we analyze the effectiveness of TASIT in a larger cohort and evaluate the impact on ALF patients with or without microcirculatory disturbance. We conducted a single-center retrospective study to evaluate the effectiveness of TASIT in patients with ALF admitted at Kyushu University Hospital between January 2005 and March 2018. TASIT is performed by injecting methylprednisolone via the proper hepatic artery for 3 days. One hundred ninety-4 patients with ALF were enrolled and analyzed in this study. Of the 87 patients given TASIT, 71 (81.6%) recovered without any complications and 16 (18.4%) died or underwent liver transplantation. Of the 107 patients not administered TASIT, 77 (72.0%) recovered and 30 (28.0%) progressed to irreversible liver failure. In the high-lactate dehydrogenase subgroup, 52 (86.7%) of the 60 patients with TASIT recovered, and the survival rate was significantly higher than that in patients who did not receive TASIT. Multivariate regression analysis revealed that the TASIT procedure was one of the significant prognostic factors in the high-lactate dehydrogenase subgroup and was significantly associated with prothrombin activity percentage improvement. TASIT is an effective treatment for patients with ALF, especially in those with microcirculatory disturbance.

Corticosteroid suppresses urea-cycle-related gene expressions in ornithine transcarbamylase deficiency.

BACKGROUND: Ornithine transcarbamylase deficiency (OTCD) is most common among urea cycle disorders (UCDs), defined by defects in enzymes associated with ureagenesis. Corticosteroid administration to UCD patients, including OTCD patients, is suggested to be avoided, as it may induce life-threatening hyperammonemia. The mechanism has been considered nitrogen overload due to the catabolic effect of corticosteroids; however, the pathophysiological process is unclear. METHODS: To elucidate the mechanism of hyperammonemia induced by corticosteroid administration in OTCD patients, we analyzed a mouse model by administering corticosteroids to OTCspf-ash mice deficient in the OTC gene. Dexamethasone (DEX; 20 mg/kg) was administered to the OTCspf-ash and wild-type (WT) mice at 0 and 24 h, and the serum ammonia concentrations, the levels of the hepatic metabolites, and the gene expressions related with ammonia metabolism in the livers and muscles were analyzed. RESULTS: The ammonia levels in Otcspf-ash mice that were administered DEX tended to increase at 24 h and increased significantly at 48 h. The metabolomic analysis showed that the levels of citrulline, arginine, and ornithine did not differ significantly between Otcspf-ash mice that were administered DEX and normal saline; however, the level of aspartate was increased drastically in Otcspf-ash mice owing to DEX administration (P < 0.01). Among the enzymes associated with the urea cycle, mRNA expressions of carbamoyl-phosphate synthase 1, ornithine transcarbamylase, arginosuccinate synthase 1, and arginosuccinate lyase in the livers were significantly downregulated by DEX administration in both the Otcspf-ash and WT mice (P < 0.01). Among the enzymes associated with catabolism, mRNA expression of Muscle RING-finger protein-1 in the muscles was significantly upregulated in the muscles of WT mice by DEX administration (P < 0.05). CONCLUSIONS: We elucidated that corticosteroid administration induced hyperammonemia in Otcspf-ash mice by not only muscle catabolism but also suppressing urea-cycle-related gene expressions. Since the urea cycle intermediate amino acids, such as arginine, might not be effective because of the suppressed expression of urea-cycle-related genes by corticosteroid administration, we should consider an early intervention by renal replacement therapy in cases of UCD patients induced by corticosteroids to avoid brain injuries or fatal outcomes.

Pirfenidone attenuates acetaminophen-induced liver injury via suppressing c-Jun N-terminal kinase phosphorylation.

Acetaminophen (APAP)-induced liver injury is the most frequent cause of acute liver failure in Western countries. Pirfenidone (PFD), an orally bioavailable pyridone derivative, is clinically used for idiopathic pulmonary fibrosis treatment and has antifibrotic, anti-inflammatory, and antioxidant effects. Here we examined the PFD effect on APAP-induced liver injury. In a murine model, APAP caused serum alanine aminotransferase elevation attenuated by PFD treatment. We performed terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) and vital propidium iodide (PI) stainings simultaneously. APAP induced TUNEL-positive/PI-negative necrosis around the central vein and subsequent TUNEL-negative/PI-positive oncotic necrosis with hemorrhage and caused the upregulation of hypercoagulation- and hypoxia-associated gene expressions. PFD treatment suppressed these findings. Western blotting revealed PFD suppressed APAP-induced c-Jun N-terminal kinase (JNK) phosphorylation despite no effect on JNK phosphatase expressions. In conclusion, simultaneous TUNEL and vital PI staining is useful for discriminating APAP-induced necrosis from typical oncotic necrosis. Our results indicated that PFD attenuated APAP-induced liver injury by suppressing TUNEL-positive necrosis by directly blocking JNK phosphorylation. PFD is promising as a new option to prevent APAP-induced liver injury.

Upregulated expression of hypoxia reactive genes in peripheral blood mononuclear cells from chronic liver disease patients.

Liver fibrosis induces intrahepatic microcirculation disorder and hypoxic stress. Hypoxic stress has the potential for an increase in the possibility of more liver fibrosis and carcinogenesis. Liver biopsy is a standard method that evaluates of intrahepatic hypoxia, however, is invasive and has a risk of bleeding as a complication. Here, we investigated the hypoxia reactive gene expressions in peripheral blood mononuclear cells (PBMC) from chronic liver disease patients to evaluate intrahepatic hypoxia in a non-invasive manner. The subjects enrolled for this study were composed of 20 healthy volunteers (HV) and 48 patients with chronic liver disease (CLD). CLD patients contained 24 patients with chronic hepatitis（CH）and 24 patients with liver cirrhosis (LC). PBMC were isolated from heparinized peripheral blood samples. We measured the transcriptional expression of hypoxia reactive genes and inflammatory cytokines by quantitative RT-PCR. mRNA expression of adrenomedullin (AM), vascular endothelial growth factor A (VEGFA) superoxide dismutase (SOD), glutathione peroxidase (GPx) (p < 0.05), Interleukin-6 (IL-6), transforming growth factor-beta (TGF-ß) and heme oxygenase-1 (HO-1) in CLD group were significantly higher than HV. AM mRNA expression is correlated with serum lactate dehydrogenase (LDH), serum albumin (Alb), IL6, and SOD mRNA expression. The hypoxia reactive gene expression in PBMCs from CLD patients was more upregulated than HV. Especially, angiogenic genes were notably upregulated and correlated with liver fibrosis. Here, we suggest that mRNA expression of AM in PBMCs could be the biomarker of intrahepatic hypoxia.

Association Between Atrial High-Rate Episodes and Ischemic/Major Bleeding Events in Patients With a Cardiac Implantable Electronic Device　- A 10-Year, Single-Center Historical Cohort Study.

BACKGROUND: An association between atrial high-rate episode (AHRE) and stroke has been reported, although data for the Asian population are limited. This study aimed to investigate the role of AHRE in ischemic and major bleeding events in patients who underwent a cardiac implantable electronic device (CIED) procedure.Methods and Results:This single-center historical cohort study included 710 patients (age: 78±11 years, 374 women) who underwent a CIED-related procedure between October 2009 and September 2019 at Shimane Prefectural Central Hospital (median follow-up period: 4.5 [2.5, 7] years, 3439 person-years). Based on the maximum AHRE burden, patients were divided into: (1) <6 min; (2) ≥6 min to 24-h; and (3) ≥24-h groups. The cumulative incidence of ischemic (ischemic stroke, systemic embolism, and transient ischemic attack) and major bleeding (≥3 Bleeding Academic Research Consortium bleeding criteria) events after the procedure were compared. Uni- and multivariate analyses were performed to identify factors associated with these events. The incidence of both events increased with the rising AHRE burden, being significantly higher in the ≥24-h group than in the <6 min group. Multivariate analysis found age ≥85 years to be the only independent factor associated with both events. CONCLUSIONS: Longer AHRE duration is associated with a high number of major bleeding and ischemic events. Monitoring these bleeding risks is mandatory when clinicians are considering anticoagulation therapy for such patients.

Microcirculatory disturbance in acute liver injury.

Microcirculatory disturbance is thought to be involved in the pathogenesis of acute liver injury (ALI). The current study examined the pathophysiologic role of hepatic microcirculatory disturbance in patients with ALI and in mouse models of ALI. Using serum aminotransferase (ALT)/lactate dehydrogenase (LDH) ratio as a hypoxic marker, 279 patients with ALI were classified into the low ALT/LDH ratio (ALT/LDH ≤1.5) and high ALT/LDH ratio group (ALT/LDH >1.5). In the low ALT/LDH ratio group, serum ALT, LDH, fibrinogen degradation products and prothrombin time-international normalized ratio were increased relative to the high ALT/LDH ratio group. Histologically, hepatic expression of tissue factor (TF) and hypoxia-related proteins was enhanced in the low ALT/LDH ratio group, and this was accompanied by sinusoidal fibrin deposition. Sinusoidal hypercoagulation and intrahepatic hypoxia was also analyzed in two different mouse models of ALI; Concanavalin A (ConA) mice and Galactosamine/tumor necrosis factor (TNF)-α (G/T) mice. Serum ALT/LDH ratio in ConA mice was significantly lower compared with G/T mice. Pimonidazole staining revealed the upregulation of hypoxia-related proteins in ConA mice. Recombinant human soluble thrombomodulin improved liver damage in ConA mice in association with reduced sinusoidal hypercoagulation and intrahepatic hypoxia. The present study provides evidence that serum ALT/LDH ratio aids in the identification of patients with ALI and intrahepatic hypoxia as a result of microcirculatory disturbance. The results facilitate the improved understanding of the pathogenesis of ALI, thereby offering a novel therapeutic strategy against ALI, which arises from sinusoidal hypercoagulation.

Incidence and Demographic Trends for Acute Coronary Syndrome in a Non-Epidemic Area During the Coronavirus Disease Pandemic in Japan　- A 2-Institutional Observational Study.

Background: We investigated the incidence of acute coronary syndrome (ACS) in a non-epidemic area of coronavirus disease-2019 (COVID-19) in Japan. Methods and Results: This observational study included consecutive patients admitted for ACS at 2 tertiary hospitals in Izumo City during the pandemic in Japan (n=42, March-July 2020). Although the monthly ACS incidence was comparable, the proportions of delayed admissions and high Killip class (III/IV) were significantly higher in this population than in historical cohorts (n=197, 2015-2019). Conclusions: Our findings stress the importance of encouraging patients with ACS-related symptoms to visit medical services promptly, especially in non-epidemic areas.

Metabolic Alteration in Hepatocellular Carcinoma: Mechanism of Lipid Accumulation in Well-Differentiated Hepatocellular Carcinoma.

Objective: Metabolic alteration is widely considered as one of the hallmarks of cancer. Hepatocellular carcinoma (HCC) presents a unique pathological feature in which lipid accumulation is common in well-differentiated HCC and rare in poorly differentiated HCC; however, the underlying mechanism remains unclear. Methods: Tissue samples were obtained from 103 HCC patients who had undergone hepatic resection and 12 living donors of liver transplantation. We evaluated metabolic gene expressions in cancer tissues as well as background noncancer tissues and compared the expressions by the degree of cancer differentiation and by liver disease states. Besides, the metabolomics was evaluated and integrated to gene expressions in nonalcoholic steatohepatitis (NASH)-HCC model mice. Results: In cancer tissues, the expression levels of enzymes related to glycolysis, pentose phosphate pathway (PPP), and fatty acid (FA) synthesis were increased and that of tricarboxylic acid (TCA) cycle and ß-oxidation were suppressed. Same metabolic alterations were observed in noncancer tissue as the liver disease progresses from healthy liver to chronic hepatitis, cirrhosis, and HCC. Similar alterations of metabolic genes were detected in NASH-HCC mice, which were consistent with the results of metabolomics. As the degree of cancer differentiation decreased, glycolysis and PPP were accelerated; however, FA synthesis and uptake were diminished. Conclusions: The metabolic alterations including glycolysis, PPP, TCA cycle, and ß-oxidation became more prominent as liver disease progresses from normal, chronic hepatitis, cirrhosis, well-, moderately, and poorly differentiated HCC. FA synthesis and uptake were highest in well-differentiated HCC, which could explain the lipid accumulation.

Trends Over Time in the Incidences of ST-Segment Elevation Myocardial Infarction and Non-ST-Segment Elevation Myocardial Infarction During the Past Decade in a Rural Japanese High-Aged Population.

BACKGROUND: In developed countries, the incidence of non-ST-segment elevation myocardial infarction (NSTEMI) has outpaced that of ST-segment elevation myocardial infarction (STEMI). However, whether this trend is observed in Japan, in which the aging of society is rapidly progressing, remains to be elucidated.Methods and Results:This study retrospectively investigated the trends over time in the incidence of acute coronary syndrome (ACS) between August 2009 and July 2019 at 2 institutions in Izumo City (in rural Japan), which has an elderly population. Crude and age-sex-adjusted incidences of total ACS, STEMI, and non-ST-segment elevation-ACS (NSTE-ACS; including NSTEMI and unstable angina pectoris) were calculated for each year. In the total population, factors associated with the development of NSTEMI were evaluated by multivariate analysis. In total, 1,087 patients were enrolled. The age-adjusted incidence of NSTE-ACS in male patients aged ≥75 years showed a significantly increasing trend. The proportion of NSTEMI per total ACS cases showed a significantly increasing trend over the entire study period. In the multivariate analysis, pre-development use of ≥3 medications for comorbidities was associated with the development of NSTEMI, independent of high-sensitivity cardiac troponin assay use. CONCLUSIONS: This study demonstrated an increasing trend in the incidence of NSTEMI in a rural high-aged Japanese population. In addition to the widespread use of high-sensitivity cardiac troponin assays, early medication use for comorbidities might have contributed to this trend.

Incidence and risk factors for cardiac implantable electronic device infection in current clinical settings in a Japanese population: A 20-year single-center observational study.

BACKGROUND: The incidence of cardiac implantable electronic device (CIED) infection is increasing worldwide. However, data regarding this phenomenon in Japan and information on factors associated with developing CIED infection are limited. Our aim was to compare the incidence of CIED infection between pre-current (past 10-20 years) and current (past 10 years) clinical settings and to investigate risk factors for CIED infection in current clinical settings in a Japanese population. METHODS: This observational study included 1749 patients (age 77 ± 12 years, 824 males) who underwent a CIED-related procedure between August 1999 and July 2019 at our institution. We defined the pre-current and current clinical setting periods as August 1999-July 2009 (period I) and August 2009-July 2019 (period II), respectively. We compared the incidence rate of CIED infection between periods and evaluated the risk factors for CIED infection in period II by multivariate analysis. RESULTS: A CIED infection was identified in 0.7% (5/709 patients) and 1.7% (17/1040) of patients in periods I and II, respectively. Notably, the rate of late (>6 months since last procedure) CIED infection was significantly increased in period II (1.3% vs. 0.1%, p < 0.01), despite the rate of early infection (≤6 months) being comparable (0.4% vs. 0.6%, p = 0.58). On multiple logistic regression, revision [odds ratio (95% confidence interval): 5.2 (1.6-16.3), p = 0.005] and age [0.96, (0.93-0.99), p = 0.007] were identified as independent risk factors for CIED infection in period II. CONCLUSIONS: Our findings suggest that the increasing incidence of CIED infection in current clinical settings was due to an increase in late CIED infection. Furthermore, revision and younger age were identified as independent risk factors for CIED infection in current clinical settings. Our data indicate that clinicians should consider whether the merit of a procedure can overcome the risk of infection when planning revision or implantation in younger patients.

Recombinant human soluble thrombomodulin ameliorates acetaminophen-induced liver toxicity in mice.

Recombinant human soluble thrombomodulin alpha (rhTM) has been developed as an anticoagulant with anti-inflammatory activity. Notably, acetaminophen (APAP) -induced liver disease (AILI) is caused by direct metabolite-induced hepatotoxicity as well as hepatic hyper-coagulation. To evaluate the utility of anticoagulant for the treatment of AILI, rhTM was administered in a mouse AILI model and liver damage was analyzed. AILI was induced in 8-week-old mice by intraperitoneal injection of APAP. rhTM (20 mg/kg) or placebo was injected at the same time as APAP administration. Serum alanine aminotransferase, fibrin degradation products and high-mobility group box 1 levels were significantly decreased in the rhTM-treated group compared with the control group. Furthermore, rhTM reduced the necrotic area and fibrin deposition in liver sections. rhTM suppressed the mRNA expression of heme oxygenase-1, plasminogen activator inhibitor type-1, tissue factors, and inflammatory cytokines compared with the control group. rhTM did not change the hepatic GSH content at 2 h after APAP injection, but restored them at 4 h after the insult. rhTM ameliorated liver damage in mice with AILI, probably via the improvement in liver perfusion induced by it's anticoagulant acitivity, which can lead to the suppression of secondary liver damage.

Fatal community-acquired Bacillus cereus pneumonia in an immunocompetent adult man: a case report.

BACKGROUND: Bacillus cereus is a gram-positive rod bacterium that is responsible for food poisoning. It is naturally widely distributed, and thus often contaminates cultures. Although it is rarely considered responsible, it can cause serious infections under certain conditions. However, lethal infections, especially in immunocompetent patients, are rare. CASE PRESENTATION: A healthy 60-year-old man developed community-acquired B. cereus pneumonia and alveolar hemorrhage unveiled by abrupt chest pain and hemoptysis with no other advance symptoms. B. cereus induced silent alveolar destruction without any local or systemic inflammatory response. Although the lesion resembled lung anthrax, there was no evidence of Bacillus anthracis toxin. CONCLUSIONS: Some isolates of B. cereus can cause anthrax-like fulminant necrotizing pneumonia in immunocompetent patients. If this type of B. cereus were used as a means of bioterrorism, it may be quite difficult to recognize as bioterrorism. We should keep B. cereus in mind as a potential pathogen of fulminant human infectious disease.

Clinical Features of Liver Injury Induced by Immune Checkpoint Inhibitors in Japanese Patients.

Aim: Immune checkpoint inhibitors (ICIs) have improved the survival rate of patients carrying various malignant neoplasms. Despite their efficacy, ICIs occasionally induce liver injury as an immune-related adverse event (irAE). This study aimed to reveal the clinical features of the hepatic irAE in Japanese patients. Methods: Among 387 patients treated with ICIs, those who developed drug-induced liver injury were investigated. We also describe the histological findings and clinical courses of four patients with hepatic irAE who underwent liver biopsy. Results: Among the 56 patients with all-grade liver injury, only 11 (19.6%) showed hepatocellular-type liver injury, which resembled autoimmune hepatitis. Thirty-four patients (60.7%) developed cholestatic or mixed-type liver injury, although only one patient showed abnormal image findings in the bile duct. Most patients with grade ≤2 liver injury improved spontaneously, while two patients with biliary dysfunction required ursodeoxycholic acid or prednisolone. Among eight patients with grade ≥3 liver injury, three required no immunosuppressants and five were treated with prednisolone (three of five patients required other types of immunosuppressants). Four patients in the case series showed diverse clinical features in terms of hepatotoxic pattern, symptoms, and the interval time between the initiation of immunotherapy and the onset of the hepatic irAE. Conclusions: Our findings suggest that ICIs could cause microscopic biliary disorder without any abnormal image finding. Because the hepatic irAE presents diverse clinical features, liver biopsy is recommended to provide appropriate treatments.

Purification and characterization of a liquefying α-amylase from alkalophilic thermophilic Bacillus sp. AAH-31.

α-Amylase (EC 3.2.1.1) hydrolyzes an internal α-1,4-glucosidic linkage of starch and related glucans. Alkalophilic liquefying enzymes from Bacillus species are utilized as additives in dishwashing and laundry detergents. In this study, we found that Bacillus sp. AAH-31, isolated from soil, produced an alkalophilic liquefying α-amylase with high thermostability. Extracellular α-amylase from Bacillus sp. AAH-31 (AmyL) was purified in seven steps. The purified enzyme showed a single band of 91 kDa on SDS-PAGE. Its specific activity of hydrolysis of 0.5% soluble starch was 16.7 U/mg. Its optimum pH and temperature were 8.5 and 70 °C respectively. It was stable in a pH range of 6.4-10.3 and below 60 °C. The calcium ion did not affect its thermostability, unlike typical α-amylases. It showed 84.9% of residual activity after incubation in the presence of 0.1% w/v of EDTA at 60 °C for 1 h. Other chelating reagents (nitrilotriacetic acid and tripolyphosphate) did not affect the activity at all. AmyL was fully stable in 1% w/v of Tween 20, Tween 80, and Triton X-100, and 0.1% w/v of SDS and commercial detergents. It showed higher activity towards amylose than towards amylopectin or glycogen. Its hydrolytic activity towards γ-cyclodextin was as high as towards short-chain amylose. Maltotriose was its minimum substrate, and maltose and maltotriose accumulated in the hydrolysis of maltooligosaccharides longer than maltotriose and soluble starch.

Longitudinal structural determinants of atherosclerotic plaque vulnerability: a computational analysis of stress distribution using vessel models and three-dimensional intravascular ultrasound imaging.

OBJECTIVES: This study theoretically examined the longitudinal structural determinants of plaque vulnerability using a color-coded stress mapping technique for several hypothetical vessel models as well as three-dimensional intravascular ultrasound (IVUS) images with use of a finite element analysis. BACKGROUND: It has been shown that an excessive concentration of stress is related to atherosclerotic plaque rupture. However, the local determinants of in-plaque longitudinal stress distribution along the coronary arterial wall remain unclear. METHODS: Using a finite element analysis, we performed a color mapping of equivalent stress distribution within plaques for three-dimensional vessel models as well as longitudinal IVUS plaque images (n = 15). Then, the effects of plaque size, shape, expansive remodeling, calcification, and lipid core on the equivalent stress distribution were examined. RESULTS: The color mapping of vessel models revealed a concentration of equivalent stress at the top of the hills and the shoulders of homogeneous fibrous plaques. Expansive remodeling and the lipid core augmented the surface equivalent stress, whereas luminal stenosis and superficial calcification attenuated the equivalent stress. The location of excessive stress concentration was modified by the distribution of the lipid core and calcification. The thickness of the fibrous cap was inversely related to the equivalent stress within the fibrous cap. However, the color mapping of IVUS plaque images showed that the equivalent stress value at the fibrous cap varied with changes in plaque shape and superficial calcification, even when the thickness of the fibrous cap remained constant. CONCLUSIONS: A distribution analysis of longitudinal stress revealed specific effects of plaque shape, size, and remodeling, as well as effects of the interior distribution of tissue components, on the concentration of stress at the plaque surface. Moreover, fibrous caps of the same thickness did not consistently represent the same vulnerability to rupture.

Detection of lipid-laden atherosclerotic plaque by wavelet analysis of radiofrequency intravascular ultrasound signals: in vitro validation and preliminary in vivo application.

OBJECTIVES: This study examined the feasibility of using a wavelet analysis of radiofrequency (RF) intravascular ultrasound (IVUS) signals in detecting lipid-laden plaque. BACKGROUND: Wavelet analysis is a new mathematical model for assessing local changes in a geometrical profile of time-series signals. METHODS: Radiofrequency IVUS signals of 85 arbitrarily selected vectors were acquired from 27 formalin-fixed noncalcified atherosclerotic plaques from human necropsy with a digitizer at 500 MHz with 8-bit resolution by use of a 40-MHz IVUS catheter. Wavelet analysis of these RF signals was performed using a Daubechies-2 wavelet to obtain a color-coded map of the correlation coefficient with the wavelet reconstructed over the x-y plane of the wavelet scale and the distance from the IVUS catheter. The plaque segment was then examined histologically after being stained with Masson's trichrome stain. This technique also was applied in vivo in 29 human coronary plaque segments. These segments were excised subsequently by directional coronary atherectomy and processed for histologic analysis. RESULTS: In the in vitro study, histologic examination revealed lipid-laden segments in 29 vectors. When performing a wavelet analysis with the Daubechies-2 wavelet, the color-coded mapping revealed a different pattern in lipid-laden plaques compared with other types of plaque. Using this wavelet analysis, lipid-laden plaque could be detected with a sensitivity of 83% (24 of 29) and a specificity of 82% (46 of 56). In the in vivo study, fatty plaque could be detected with a sensitivity of 81% (13 of 16) and a specificity of 85% (11 of 13) with this method. CONCLUSIONS: Wavelet analysis of RF IVUS signals enabled in vitro as well as in vivo detection of lipid-laden plaque. This method may be useful in assessing plaque vulnerability in patients with coronary artery disease.