Serum interleukin-6 levels at the start of the second course of atezolizumab plus bevacizumab therapy predict therapeutic efficacy in patients with advanced hepatocellular carcinoma: a multicenter analysis.

BACKGROUND AND AIM: Serum interleukin-6 (IL-6) before the administration of atezolizumab plus bevacizumab (Atez + Bev) is a prognostic biomarker in patients with hepatocellular carcinoma (HCC) treated with Atez + Bev. We previously revealed that the neutrophil-to-lymphocyte ratio and serum chemokine levels during treatment with Atez + Bev were more useful as prognostic biomarkers. Therefore, we examined the predictive ability of serum IL-6 for the efficacy of Atez + Bev in patients with HCC. METHODS: We enrolled 94 patients with HCC who received treatment with Atez + Bev. Initial responses were assessed through dynamic computed tomography or magnetic resonance imaging. The levels of IL-6 in serum were measured before and at the initiation of the second course of Atez + Bev. Subsequently, the relationship of IL-6 levels with treatment efficacy was evaluated. RESULTS: IL-6 levels at the initiation of the second course tended to be higher in patients with progressive disease versus those with non-progressive disease in the initial evaluation (P = 0.054). Moreover, the cutoff value (7.4 pg/mL) was useful in stratifying patients by overall survival (i.e. low vs high: not reached vs 21.4 months, respectively, P = 0.001) and progression-free survival (low vs high: 11.9 vs 5.2 months, respectively, P = 0.004). This result was reproduced in patients with HCC who received Atez + Bev as first-line therapy. In the multivariate analyses, IL-6 levels at the initiation of the second course were independent predictive factors for progression-free and overall survival. CONCLUSIONS: Serum levels of IL-6 at the initiation of the second course of treatment may predict Atez + Bev efficacy and prognosis in HCC.

Prognostic nutritional index after introduction of atezolizumab with bevacizumab predicts prognosis in advanced hepatocellular carcinoma: A multicenter study.

INTRODUCTION: Atezolizumab plus bevacizumab (Atez/Bev) is the preferred treatment for advanced hepatocellular carcinoma (HCC). However, biomarkers of therapeutic efficacy have remained unclear. We took a retrospective approach to explore the role of prognostic nutritional index (PNI) for predicting the outcomes of Atez/Bev treatment. METHODS: One hundred twenty-five HCC patients were enlisted; these patients received Atez/Bev treatment and underwent dynamic computerized tomography/magnetic resonance imaging to determine the treatment response on at least one occasion between October 2020 and January 2023, and their PNI before treatment and at the beginning of the second cycle (PNI-2c) was evaluated. RESULTS: During the initial evaluation, 2 (2%), 28 (22%), 70 (56%), and 25 (20%) patients exhibited a complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD), respectively. Patients with non-PD tended to have higher PNI at baseline and PNI-2c than those with PD (p = 0.245 and 0.122, respectively), with optimal baseline PNI and PNI-2c cut-off values of 42.6 and 40.4, respectively. PNI at baseline could not be used to predict overall survival (OS) or progression-free survival (PFS). However, PNI-2c predicted OS and PFS (PNI-2c ≥ 40.4 vs. < 40.4: 25.3 vs. 16.2 months, P = 0.008 for OS; 12.7 vs. 8.4 months, P = 0.036 for PFS). A multivariate analysis showed a significant association between PNI-2c and OS. CONCLUSIONS: PNI-2c is a predictor of prognosis in HCC patients treated with Atez/Bev therapy.

Serum CXCL10 levels at the start of the second course of atezolizumab plus bevacizumab therapy predict therapeutic efficacy in patients with advanced BCLC stage C hepatocellular carcinoma: A multicenter analysis.

BACKGROUND & AIMS: Relationships of serum C-C motif chemokine ligand 5 (CCL5) and C-X-C motif chemokine ligand 10 (CXCL10) levels with hot immune features have been reported in patients with hepatocellular carcinoma (HCC). Therefore, we examined the utility of their levels for predicting the efficacy of atezolizumab plus bevacizumab (Atez/Bev) in patients with HCC. DESIGN: In total, 98 patients with HCC treated with Atez/Bev were enrolled, and their initial responses were evaluated at least once via dynamic computed tomography or magnetic resonance imaging. Serum CCL5 and CXCL10 levels were assessed by enzyme-linked immunosorbent assay before treatment and at the start of the second course of Atez/Bev therapy, and their relationships with treatment efficacy were determined. RESULTS: No analyzed factor was associated with the initial therapeutic response. Among the 56 patients with Barcelona Clinic Liver Cancer (BCLC) stage C, serum CXCL10 levels at the beginning of course two (CXCL10-2c) tended to be higher in responders than in non-responders in the initial evaluation, and its optimal cutoff level of 690 pg/mL could be used to stratify patients regarding overall survival (OS; high vs. low: not reached vs. 17.6 months, p = 0.034) and progression-free survival (high vs. low: 13.6 vs. 5.1 months, p = 0.014). In multivariate analysis, high CXCL10 levels and neutrophil-to-lymphocyte ratios at the start of course two and Child-Pugh stage A at baseline were independent predictive factors of improved OS. CONCLUSIONS: Serum CXCL10-2c levels were predictive of Atez/Bev efficacy in patients with BCLC stage C HCC.

BRAF V600E-mutated Colorectal Neuroendocrine Carcinoma Effectively Treated with a Chemotherapy Protocol for BRAF-mutated Metastatic Colorectal Cancer: A Case Report.

Metastatic colorectal neuroendocrine carcinoma (NEC) is often treated using a chemotherapy protocol for small-cell lung cancer; however, the prognosis is extremely poor. A 55-year-old woman with BRAF V600E-mutated transverse colon NEC and liver metastases underwent colectomy followed by FOLFOXIRI plus bevacizumab. Consequently, the liver metastases markedly shrank. Owing to later worsening of the liver metastases, she received encorafenib and binimetinib plus cetuximab. Despite discontinuing binimetinib due to myalgia, she had a long-term response with a progression-free survival of 14 months and an overall survival of more than 27 months. A chemotherapy protocol for BRAF-mutated metastatic colorectal cancer may be a treatment option for BRAF V600E-mutated colorectal NEC.

The neutrophil-to-lymphocyte ratio at the start of the second course during atezolizumab plus bevacizumab therapy predicts therapeutic efficacy in patients with advanced hepatocellular carcinoma: A multicenter analysis.

AIM: Atezolizumab plus bevacizumab (Atez/Bev) therapy is expected to have good therapeutic efficacy for patients with advanced hepatocellular carcinoma (HCC). However, the clinical indicators that predict therapeutic efficacy have not been established. We retrospectively investigated whether the neutrophil-to-lymphocyte ratio (NLR) during Atez/Bev therapy could predict therapeutic efficacy. METHOD: In total, 110 patients with HCC were enrolled; they were treated with Atez/Bev therapy and evaluated for their initial response by dynamic CT or MRI at least once between October 2020 and July 2022. RESULTS: Of the 110 patients with HCC at the initial evaluation, two (2%) showed a complete response (CR), 22 (20%) partial response (PR), 62 (56%) stable disease (SD), and 24 (21%) progressive disease (PD). The NLR at the start of the second course (NLR-2c) increased from CR + PR to SD to PD. There was no significant association between the baseline NLR and the initial therapeutic response. Patients with CR + PR had lower NLR-2c values than those with SD + PD (p < 0.001) and the optimal cut-off value of NLR-2c was 1.97. Patients with NLR-2c <1.97 had better overall survival and progression-free survival (PFS) than those with NLR-2c ≥1.97 (p = 0.005 for overall survival; p < 0.001 for PFS). A multivariate analysis showed that female sex, higher PIVKA-II levels at baseline, and higher values of NLR-2c were significantly associated with poorer PFS. CONCLUSIONS: The NLR-2c value predicts the initial therapeutic response and prognosis of patients with HCC treated with Atez/Bev therapy.

Outcome of nucleos(t)ide analog cessation in patients with treatment for prevention of or against hepatitis B virus reactivation.

AIM: We retrospectively investigated patients with administration of nucleos(t)ide analogs (NAs) for prevention of or against hepatitis B virus (HBV) reactivation, and their clinical outcomes after cessation of the NA. METHODS: We enrolled 180 patients who were positive for HBsAg when they started immunosuppressive therapy or chemotherapy and an NA was administered to prevent HBV reactivation (HBV carrier group), and 82 patients with resolved HBV infection who started administration of an NA after HBV reactivation (de novo HBV group). Cessation of the NA depended on each physician's judgment without definite criteria. RESULTS: A total of 27 patients in the HBV carrier group and 22 in the de novo HBV group stopped NA therapy. In the HBV carrier group, 16 patients experienced virological relapse, which was defined as HBV DNA levels ≥20 IU/ml, and one with hematological disease had an alanine aminotransferase flare after cessation of NA. Of the 16 patients, the NA was reintroduced in three, whereas, the remaining 13 had low levels of HBV DNA and no alanine aminotransferase flare. In the de novo HBV group, virological relapse occurred in six patients, and one with hematological disease had an alanine aminotransferase flare after cessation of the NA. The NA was reintroduced in four of the six patients. CONCLUSIONS: We may be able to consider to cease NA therapy proactively in HBV carriers and resolved patients with non-hematological disease, if their primary diseases are under remission after completion of immunosuppressive therapy or chemotherapy. However, careful follow up is necessary after stopping NA therapy.

Efficacy of minocycline hydrochloride aspiration sclerotherapy with additional monoethanolamine oleate aspiration sclerotherapy for symptomatic hepatic cysts.

AIM: Minocycline hydrochloride (MINO) aspiration sclerotherapy (AS) has been widely used for treating hepatic cysts (HC). However, cyst recurrence remains problematic. Information on monoethanolamine oleate (EO) AS, another effective HC treatment, is currently limited. We investigated the efficacy of EO on ineffective MINO treatments, and the relationship between MINO AS and cyst fluid pH. METHODS: A total of 22 cases with symptomatic HC underwent AS with 500 mg of MINO from January 2016 to June 2021. Cyst fluid pH was measured before and after MINO injection. Cyst volume ratio (CVR, %) after 2 weeks was calculated as follows:cyst volume 2 weeks after MINO injection / pre-treatment cyst volume × 100. Treatment was completed if CVR after 2 weeks was ≤35% (MINO-group). For patients with CVR >35%, 2 g of EO was added (MINO/EO-group). Cyst volume ratio was measured every 12 months thereafter. RESULTS: There were no recurrence symptoms in any of the patients during follow-up. Of the 22 cases, 21 had CVR ≤20% after 12 months. The MINO/EO-group (n = 8) tended to have smaller CVRs after 12 months than the MINO-group (n = 14). Cyst volume ratio after 2 weeks was correlated to pH change (p = 0.012) and was larger in patients whose pH decreased by <1.5 (p = 0.015). All adverse events were mild, including in elderly patients. CONCLUSION: Adding EO is an effective and safe treatment for symptomatic HC when MINO AS alone is insufficient. Patients with pH decreases of <1.5 should be considered for additional EO treatment.

[A case of gastric cancer showing a durable response after the discontinuation of nivolumab due to the early onset of immune-related adverse events].

The Japanese guidelines for the treatment of gastric cancer recommend nivolumab as third-line chemotherapy for metastatic gastric cancer. We report a case of gastric cancer exhibiting a durable response after the discontinuation of nivolumab due to the early onset of immune-related adverse event (irAE). A 64-year-old man with advanced HER2-positive gastric cancer and distant lymph node metastasis received nivolumab as fourth-line therapy. After two courses of nivolumab, the lymph nodes showed progression. However, the treatment was discontinued because of interstitial pneumonia as an irAE. Disease regression was sustained for approximately 11 months without the readministration of nivolumab.

Phase II Prospective Study of Trastuzumab in Combination with S-1 and Oxaliplatin (SOX100) Therapy for HER2-Positive Advanced Gastric Cancer.

PURPOSE: The standard first-line treatment for human epidermal growth factor receptor type 2 (HER2)-positive advanced gastric cancer (AGC) is trastuzumab in combination with cisplatin and fluoropyrimidines. We evaluated the efficacy and safety of S-1 and oxaliplatin (100 mg/m2) (SOX100) combined with trastuzumab, a monoclonal antibody against HER2 for HER2-positive AGC. METHODS: In this single-arm, multicenter phase II study, patients with HER2-positive AGC received S-1 (80-120 mg per day) orally on days 1-14, oxaliplatin (100 mg/m2) intravenously on day 1, and trastuzumab (8 mg/kg on day 1 of the first cycle, followed by 6 mg/kg every 3 weeks) intravenously. The primary end point was 1-year survival rate. The secondary end points included overall survival (OS), progression-free survival (PFS), overall response rate (ORR), and safety. RESULTS: A total of 25 patients from six centers were enrolled from December 2015 to March 2020. In the 25 patients evaluable for analysis, the 1-year survival rate was 70.8% [90% confidence interval (CI) = 55.5-86.1%], whereas the median OS, PFS, and ORR were 17.8 (95% CI 10.5-22.9) months, 7.6 (95% CI 5.0-10.9) months, and 75.0% (95% CI 53.3-90.2), respectively. Major grade 3/4 adverse events included anorexia (20%), anemia (16%), peripheral sensory neuropathy (16%), and diarrhea (15%). CONCLUSION: SOX100 combined with trastuzumab was effective with a favorable safety profile in patients with HER2-positive AGC.

Efficacies of first and second tumor necrosis factor inhibitors in refractory ulcerative colitis patients in real-world practice.

BACKGROUND: Switching tumor necrosis factor-α inhibitors is an important treatment option for refractory ulcerative colitis (UC) patients who fail the first anti-tumor necrosis factor-α therapy, although many questions about this option remain unanswered. METHODS: The efficacy of the second anti-tumor necrosis factor-α therapy in refractory UC patients who failed the first anti-tumor necrosis factor-α therapy was examined using the Mayo score as a measure of disease activity at week 8. The efficacy of the first anti-tumor necrosis factor-α therapy before treatment and at weeks 8 and 52 was also evaluated in real-world practice. RESULTS: There were no significant differences in remission induction and maintenance between infliximab and adalimumab as the first anti-tumor necrosis factor-α therapy in UC patients. Of 123 UC patients, 21 (17.1%) switched tumor necrosis factor-α inhibitors. Eight (38.1%), 4 (19.0%), 7 (33.3%), and 2 (9.5%) patients switched from infliximab to adalimumab, infliximab to golimumab, adalimumab to infliximab, and adalimumab to golimumab, respectively. Three (100%) with intolerance to the first anti-tumor necrosis factor-α therapy, 5 (41.7%) with loss of response to the first anti-tumor necrosis factor-α therapy, and 1 (20.0%) with no improvement with the first anti-tumor necrosis factor-α therapy had clinical remission at week 8. CONCLUSIONS: Switching tumor necrosis factor-α inhibitors is more effective for refractory UC patients who are intolerant and lose response to the first anti-tumor necrosis factor-α therapy rather than for those showing no improvement with the first anti-tumor necrosis factor-α therapy. Patients with primary failure of anti-tumor necrosis factor-α therapy should be switched to another class of drug.

Adalimumab Dose-Escalation Therapy Is Effective in Refractory Crohn's Disease Patients with Loss of Response to Adalimumab, Especially in Cases without Previous Infliximab Treatment.

BACKGROUND/AIMS: Adalimumab dose escalation is one of the most important options in refractory Crohn's disease patients with loss of response to adalimumab. The goal of this study was to evaluate the effectiveness of adalimumab dose escalation in Crohn's disease patients with loss of response to adalimumab, since there are few reports of adalimumab dose escalation, especially in East Asia. METHODS: The clinical response to adalimumab dose escalation in Crohn's disease patients with loss of response to adalimumab was evaluated retrospectively, using the Crohn's disease activity index score, serum C-reactive protein levels, and endoscopic analyses. RESULTS: Of the 203 Crohn's disease patients treated with anti-tumor necrosis factor, 14 refractory Crohn's disease patients with loss of response to adalimumab received adalimumab dose-escalation therapy. The C-reactive protein level was significantly reduced from the start to weeks 12 and 52 of adalimumab dose escalation in the whole group, although there were no significant reductions of Crohn's disease activity index scores. Both Crohn's disease activity index scores and C-reactive protein levels were significantly reduced from the start to weeks 12 and 52 of adalimumab dose escalation in patients without previous infliximab treatment, although C-reactive protein levels were positive in all cases with previous infliximab exposure at weeks 12 and 52. Endoscopic mucosal healing was achieved with adalimumab dose escalation in 2 cases without previous infliximab treatment. CONCLUSIONS: Adalimumab dose-escalation therapy is effective in refractory Crohn's disease patients with loss of response to adalimumab, especially in cases without previous infliximab treatment.

Development of a real-time wave field reconstruction TEM system (II): correction of coma aberration and 3-fold astigmatism, and real-time correction of 2-fold astigmatism.

In this study, a function for the correction of coma aberration, 3-fold astigmatism and real-time correction of 2-fold astigmatism was newly incorporated into a recently developed real-time wave field reconstruction TEM system. The aberration correction function was developed by modifying the image-processing software previously designed for auto focus tracking, as described in the first article of this series. Using the newly developed system, the coma aberration and 3-fold astigmatism were corrected using the aberration coefficients obtained experimentally before the processing was carried out. In this study, these aberration coefficients were estimated from an apparent 2-fold astigmatism induced under tilted-illumination conditions. In contrast, 2-fold astigmatism could be measured and corrected in real time from the reconstructed wave field. Here, the measurement precision for 2-fold astigmatism was found to be ±0.4 nm and ±2°. All of these aberration corrections, as well as auto focus tracking, were performed at a video frame rate of 1/30 s. Thus, the proposed novel system is promising for quantitative and reliable in situ observations, particularly in environmental TEM applications.

Development of a real-time wave field reconstruction TEM system (I): incorporation of an auto focus tracking system.

We have developed a real-time wave field reconstruction transmission electron microscope system that enables auto focus tracking at a video rate. In the developed system, a high-speed image calculation technique using a graphical processing unit was incorporated along with two techniques facilitating high-speed focus control using high-voltage modulation and weighted image integration using exposure time control. By utilizing these techniques, the sample drift induced in the Z-axis direction can be measured and automatically corrected for every 1/30 of a second. The auto focus tracking system can be operated in the sample drift range of ±150 nm with a precision of ~0.4 nm. In addition to amorphous samples, the system can be used to examine thin crystalline samples, which indicates that atomic structure analysis can be performed in real time with high reliability even when heavy drift occurs in the Z-axis direction.

Persistent reflux symptoms cause anxiety, depression, and mental health and sleep disorders in gastroesophageal reflux disease patients.

Some patients with gastroesophageal reflux disease experience persistent reflux symptoms despite proton pump inhibitor therapy. These symptoms reduce their health-related quality of life. Our aims were to evaluate the relationship between proton pump inhibitor efficacy and health-related quality of life and to evaluate predictive factors affecting treatment response in Japanese patients. Using the gastroesophageal reflux disease questionnaire, 145 gastroesophageal reflux disease patients undergoing proton pump inhibitor therapy were evaluated and classified as responders or partial-responders. Their health-related quality of life was then evaluated using the 8-item Short Form Health Survey, the Pittsburgh Sleep Quality Index, and the Hospital Anxiety and Depression Scale questionnaires. Sixty-nine patients (47.6%) were partial responders. These patients had significantly lower scores than responders in 5/8 subscales and in the mental health component summary of the 8-item Short Form Health Survey. Partial responders had significantly higher Pittsburgh Sleep Quality Index and Hospital Anxiety and Depression Scale scores, including anxiety and depression scores, than those of responders. Non-erosive reflux disease and double proton pump inhibitor doses were predictive factors of partial responders. Persistent reflux symptoms, despite proton pump inhibitor therapy, caused mental health disorders, sleep disorders, and psychological distress in Japanese gastroesophageal reflux disease patients.

Coexpression of organic anion-transporting polypeptides 1B3 and multidrug-resistant proteins 2 increases the enhancement effect of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid on hepatocellular carcinoma in magnetic resonance imaging.

AIM: We aimed to elucidate the relationship between the contrast enhancement effect of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) on magnetic resonance imaging (MRI) of hepatocellular carcinomas (HCC) and the expressions of hepatocyte transporters (i.e. organic anion-transporting polypeptide [OATP]1B3, multidrug-resistant protein [MRP]2 and MRP3) and to clarify the characteristics of HCC with an MRI high-contrast enhancement effect. METHODS: We retrospectively examined the relationship between the relative enhancement ratio (RER) of HCC, absolute and relative immunohistochemical staining scores of hepatocyte transporters, and histological differentiation of 22 HCC from 21 patients who had undergone preoperative Gd-EOB-DTPA-enhanced MRI. RESULTS: RER had a significant correlation with OATP1B3 expression according to the absolute and relative scores (P = 0.016 vs 0.0006). The RER of HCC with high OATP1B3 and MRP2 expression levels was higher than that of HCC with low OATP1B3 or MRP2 expression levels (P = 0.0003). The RER of HCC with higher OATP1B3 rates was greater than that of HCC with lower OATP1B3 rates (P = 0.0005). HCC histological differentiation showed a significant correlation with OATP1B3 expression and RER (P = 0.023 vs 0.0095). CONCLUSION: We found that coexpression of OATP1B3 and MRP2 influenced the high contrast enhancement of HCC on MRI.

[A case of malignant tumor of the ascending part of duodenum with osteoclast-like giant cells].

Extraskeletal neoplasms with osteoclast-like giant cells are very rare. These tumors are most frequently reported in the breast and pancreas, and but rarely in other sites. We report a case of duodenal malignant tumor with osteoclast-like giant cells. The patient was a 76-year-old man who presented with vomiting. Computed tomography, magnetic resonance imaging, and gastrointestinal endoscopy revealed a giant tumor in the ascending part of duodenum. Biopsy specimens showed an undifferentiated malignant tumor with benign multinucleated giant cells. Immunohistochemical staining indicated that the tumor cells were reactive with vimentin, but not with epithelial markers or the other mesenchymal markers, and the multinucleated giant cells were reactive with CD68. Thus, we diagnosed a malignant tumor of the ascending part of duodenum with osteoclast-like giant cells. To the best of our knowledge, this is the first case of duodenal malignant tumor with osteoclast-like giant cells in Japan.

Combination therapy with direct hemoperfusion using polymyxin B-immobilized fiber and oral vancomycin improves fulminant pseudomembranous colitis by reducing the elevated endogenous cannabinoids and inflammatory cytokines: report of a case.

This paper reports a case of fulminant pseudo-membranous colitis which did not lead to septic shock. The case was improved by combination therapy with direct hemoperfusion using polymyxin B-immobilized fiber and oral vancomycin. Direct hemoperfusion using polymyxin B-immobilized fiber has been demonstrated to have excellent therapeutic effects for the treatment of septic shock by removing circulating lipopolysaccharide. In the present case, the combination therapy dramatically improved clinical status of the patient. The clinical improvement occurred in parallel with a decrease in APACHE II score (from 20 to 14 points), serum levels of endogenous cannabinoids (anandamide and 2-arachidonylglycerol), and inflammatory cytokine (interleukin-6). Thus, direct hemoperfusion is strongly recommended in cases of fulminant pseudomembranous colitis, because direct hemoperfusion using polymyxin B-immobilized fiber reduces inflammatory cytokines by absorbing endogenous cannabinoids and, thereby, improves the patient's condition.

Effects of combination therapy with direct hemoperfusion using polymyxin B-immobilized fiber and oral vancomycin on fulminant pseudomembranous colitis with septic shock.

We report 2 cases of fulminant pseudomembranous colitis with septic shock. The first case showed few symptoms, whereas the second case showed recurrence. Both cases rapidly developed shock and blood pressure was uncontrollable except with the use of pressor agents. Direct hemoperfusion using polymyxin B-immobilized fiber, which was previously demonstrated to have excellent therapeutic effects for the treatment of hypotension in septic shock by removing circulating lipopolysaccharide and oral vancomycin dramatically improved both cases' clinical status and decreased their APACHE II scores (from 18 to 8 and from 16 to 9 points, respectively). Therefore, we suggest that direct hemoperfusion using polymyxin B-immobilized fiber improved hypotension-correcting cytokine balance with adsorption of endogenous cannabinoids in serum. Although colectomy is often performed to treat fulminant pseudomembranous colitis with septic shock, direct hemoperfusion can be easily performed with little risk to the patient. These cases strongly indicated that our combination therapy provides an important treatment for fulminant pseudomembranous colitis with septic shock.

Development of computer-assisted minimal-dose system with beam blanker for TEM.

A computer-assisted minimal-dose system has been developed for the high-resolution observation of radiation-sensitive samples using a transmission electron microscope (TEM). This system consists of a CCD camera, a beam blanker and a control computer (PC) that also controls the TEM. A sample is illuminated by an electron beam only when the CCD camera takes images; otherwise, the beam blanker cuts off the electron beam. Emulated images, which are calculated from the images taken and the variable parameters of the TEM, such as magnification and sample stage position, are displayed on the control PC display. After a few times of repetition of exposures and emulations, the sample is positioned to final observation area. Subsequently to select the observation area, the system automatically adjusts the focus position from two different illuminating angle images and the TEM conditions are appropriate for taking a final image. The total electron dose before the final image is taken can be markedly decreased because the sample is irradiated by an electron beam only when images are taken. For the final image, a three-dimensional Fourier filtering method (3DFFM), which corrects the spherical aberration for the through-focus image series and enables the selection of the optimum focus condition later, is also included in our system.

Separation of linear and non-linear imaging components in high-resolution transmission electron microscope images.

Linear and non-linear image components in high-resolution transmission electron microscope images were successfully separated by applying a bandpass filter to the three-dimensional Fourier spectrum of its through-focus series of images. In the observed lattice image of a wedgeshaped Si [110] crystal, we determined the magnitude of the contribution of the non-linear imaging components to the total image intensity distribution. The contribution was proved to become sometimes larger than that of the linear imaging component, even at a thickness of 13 nm.