Publications by authors named "Yoh Hamada"

12 Publications

  • Page 1 of 1

[Ischemic Colitis after Closure of Temporary Ileostomy for Low Anterior Resection of Rectal Cancer in a Dialysis Patient-A Case Report].

Gan To Kagaku Ryoho 2021 Feb;48(2):279-281

Dept. of Surgery, Hachinohe City Hospital.

Dialysis patients are at increased risk of ischemic colitis and are likely to develop irreversible ischemic colitis. We report a rare case of ischemic colitis after the closure of a temporary ileostomy for low anterior resection(LAR)of rectal cancer in a dialysis patient. A 77-year-old man undergoing maintenance dialysis was diagnosed as having colorectal cancer with a type 2 tumor at the anastomosis site of high anterior resection performed for sigmoid colon cancer 14 years ago. After undergoing excision which included the anastomosis site of the previous operation, LAR with anastomosis in the transverse colon and rectum and temporary ileostomy were performed. Seven months later, closure of the temporary ileostomy was performed, which resulted in ileus and septic shock. Computed tomography(CT)revealed inflammation in the colon on the oral side of the anastomosis, which was diagnosed as ischemic colitis. Ischemic colitis did not improve with conservative treatment, and fever reoccurred at each maintenance dialysis session. Therefore, ileostomy was performed again, but multiple organ failure due to disseminated intravascular coagulopathy(DIC)progressed and he died. It is considered that Hartmann's operation should be selected for dialysis patients with serious underlying diseases, and if ischemic colitis is observed after closure of the stoma temporary colostomy in such patients, the lesion site of ischemic colitis should be excised promptly and colostomy should be performed again.
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February 2021

Infected Massive Thrombosed Persistent Sciatic Artery Aneurysm Treated by Small Incision Drainage: A Case Report.

EJVES Vasc Forum 2020 24;49:45-47. Epub 2020 Nov 24.

Department of Surgery, Tohoku University Hospital, Sendai, Japan.

Introduction: Persistent sciatic artery is a rare vascular anomaly. The occurrence of infected persistent sciatic artery aneurysm (PSAA) is extremely rare.

Report: An 84 year old woman who was under observation for a massive thrombosed right PSAA since the age of 74 presented with severe pain in her right lower limb. The patient was diagnosed with the infected PSAA by computed tomography and laboratory test. The condition was treated with antibiotics as well as drainage and removal of the infected thrombus with a small incision. Subsequently, the patient's symptoms improved, and she was discharged ambulatory. Sixteen months after the surgery, her condition remained good, with no evidence of recurrent infection.

Conclusion: Extensive debridement requires a large muscle incision and carries with it a risk of sciatic nerve injury. However, a thrombosed aneurysm has little risk of haemorrhage. Therefore, drainage and removal of the thrombus via a small incision, which is less invasive, was considered effective for this infected thrombosed PSAA.
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http://dx.doi.org/10.1016/j.ejvsvf.2020.11.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7744702PMC
November 2020

Heterogeneous Drug Efficacy of an Antibody-Drug Conjugate Visualized Using Simultaneous Imaging of Its Delivery and Intracellular Damage in Living Tumor Tissues.

Transl Oncol 2020 Jun 11;13(6):100764. Epub 2020 May 11.

Department of Breast and Endocrine Surgical Oncology, Graduate School of Medicine, Tohoku University, Sendai, Miyagi 980-8574, Japan.

Anticancer drug efficacy varies because the delivery of drugs within tumors and tumor responses are heterogeneous; however, these features are often more homogenous in vitro. This difference makes it difficult to accurately determine drug efficacy. Therefore, it is important to use living tumor tissues in preclinical trials to observe the heterogeneity in drug distribution and cell characteristics in tumors. In the present study, to accurately evaluate the efficacy of an antibody-drug conjugate (ADC) containing a microtubule inhibitor, we established a cell line that expresses a fusion of end-binding protein 1 and enhanced green fluorescent protein that serves as a microtubule plus-end-tracking protein allowing the visualization of microtubule dynamics. This cell line was xenografted into mice to create a model of living tumor tissue. The tumor cells possessed a greater number of microtubules with plus-ends, a greater number of meandering microtubules, and a slower rate of microtubule polymerization than the in vitro cells. In tumor tissues treated with fluorescent dye-labeled ADCs, heterogeneity was observed in the delivery of the drug to tumor cells, and microtubule dynamics were inhibited in a concentration-dependent manner. Moreover, a difference in drug sensitivity was observed between in vitro cells and tumor cells; compared with in vitro cells, tumor cells were more sensitive to changes in the concentration of the ADC. This study is the first to simultaneously evaluate the delivery and intracellular efficacy of ADCs in living tumor tissue. Accurate evaluation of the efficacy of ADCs is important for the development of effective anticancer drugs.
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http://dx.doi.org/10.1016/j.tranon.2020.100764DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7218300PMC
June 2020

Midaortic Syndrome due to Takayasu Arteritis in a Child with Acute Decompensated Cardiac Failure Managed by an Emergency Axillo-External Iliac Artery Bypass: A Follow-Up Case Report of Long-Term Outcomes.

Ann Vasc Surg 2020 Apr 18;64:408.e5-408.e9. Epub 2019 Oct 18.

Department of Surgery, Tohoku University Hospital, Aoba-ku, Sendai, Japan.

Midaortic syndrome (MAS) is characterized by a diffuse narrowing of the distal thoracic or abdominal aorta and is concomitant with various etiologies. The common symptoms of MAS include severe hypertension or arterial insufficiency distal to the stenosis. This includes lower extremity claudication and heart failure due to afterload mismatch. We present the case of an 8-year-old girl who developed acute decompensated cardiac, respiratory, and renal failures because of the occlusion of the descending aorta secondary to Takayasu arteritis (TA). Although thoracoabdominal-aortic bypass is usually performed for patients with MAS, the procedure was considered too invasive, given the patient's condition. Therefore, we performed an emergency axillo-external iliac artery bypass for revascularization. Subsequently, organ failure improved and she was discharged. At postoperative 10 years, an asymptomatic pseudoaneurysm was detected at the distal anastomosis, for which revision surgery was performed. Overall, the long-term prognosis was satisfactory, suggesting that this procedure is less invasive and effective for treatment of MAS due to TA, in emergencies.
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http://dx.doi.org/10.1016/j.avsg.2019.09.026DOI Listing
April 2020

Automated Quantification of Extranuclear ERα using Phosphor-integrated Dots for Predicting Endocrine Therapy Resistance in HR/HER2 Breast Cancer.

Cancers (Basel) 2019 Apr 12;11(4). Epub 2019 Apr 12.

Department of Medical Physics, Graduate School of Medicine, Tohoku University, Sendai, Miyagi 980-8574, Japan.

In addition to genomic signaling, Estrogen receptor alpha (ERα) is associated with cell proliferation and survival through extranuclear signaling contributing to endocrine therapy (ET) resistance. However, the relationship between extranuclear ERα and ET resistance has not been extensively studied. We sought to measure extranuclear ERα expression by immunohistochemistry using phosphor-integrated dots (IHC-PIDs) and to assess its predictive value for ET resistance. After quantitative detection of ERα by IHC-PIDs in vitro, we developed "the nearest-neighbor method" to calculate the extranuclear ERα. Furthermore, tissue sections from 65 patients with HR+/HER2- BC were examined by IHC-PIDs, and the total ERα, nuclear ERα, extranuclear ERα PIDs score, and ratio of extranuclear-to-nuclear ERα (ENR) were measured using the novel method. We demonstrate that quantification of ERα using IHC-PIDs exhibited strong correlations to real-time qRT-PCR ( = 0.94) and flow cytometry ( = 0.98). High ERα ENR was significantly associated with poor overall survival ( = 0.048) and disease-free survival (DFS) ( = 0.007). Multivariate analysis revealed that the ERα ENR was an independent prognostic factor for DFS [hazard ratio, 3.8; 95% CI, 1.4-11.8; = 0.006]. Our automated measurement has high accuracy to localize and assess extranuclear ERα. A high ERα ENR in HR/HER2 BC indicates decreased likelihood of benefiting from ET.
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http://dx.doi.org/10.3390/cancers11040526DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6520781PMC
April 2019

Quantitative analyses of amount and localization of radiosensitizer gold nanoparticles interacting with cancer cells to optimize radiation therapy.

Biochem Biophys Res Commun 2019 01 12;508(4):1093-1100. Epub 2018 Dec 12.

Department of Medical Physics, Graduate School of Medicine, Tohoku University, Sendai, Miyagi, 980-8575, Japan. Electronic address:

Previous studies showed that gold nanoparticles (AuNPs) are useful radiosensitizers which optimize radiation therapy under low-dose radiation. However, the mechanisms of AuNP radiosensitization, including the amount and localization of the AuNPs interacting with cancer cells, has not yet been quantified. To answer these questions, we prepared AuNPs conjugated with anti-human epidermal growth factor receptor type 2 (HER2) antibody via polyethylene glycol (PEG) chains (AuNP-PEG-HER2ab). AuNP-PEG-HER2ab specifically bound to the HER2-expressing cancer cells and entered the cells via endocytosis. Whether endocytosis of AuNP-PEG-HER2ab occurred had no effect on radiosensitization efficacy by AuNP-PEG-HER2ab in vitro. The radiosensitization efficacy in vitro depended on dose of AuNP-PEG-HER2ab or dose of X-ray. Moreover, AuNP-PEG-HER2ab administrated into tumor-bearing mice was localized to both the periphery of the tumor tissue and near the nuclei in cancer cells in tumor deep tissue. The localization of AuNP-PEG-HER2ab in tumor tissues was important factors for in vivo powerful radiosensitization efficacy.
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http://dx.doi.org/10.1016/j.bbrc.2018.12.016DOI Listing
January 2019

Thermo-triggered Release of CRISPR-Cas9 System by Lipid-Encapsulated Gold Nanoparticles for Tumor Therapy.

Angew Chem Int Ed Engl 2018 02 15;57(6):1491-1496. Epub 2018 Jan 15.

CAS Center for Excellence in Nanoscience, Beijing Engineering Research Center for BioNanotechnology, CAS Key Lab for Biological Effects of Nanomaterials and Nanosafety, National Center for NanoScience and Technology, No. 11, BeiYiTiao, ZhongGuanCun, Beijing, 100190, China.

CRISPR/Cas9 system is a powerful toolbox for gene editing. However, the low delivery efficiency is still a big hurdle impeding its applications. Herein, we report a strategy to deliver Cas9-sgPlk-1 plasmids (CP) by a multifunctional vehicle for tumor therapy. We condensed CPs on TAT peptide-modified Au nanoparticles (AuNPs/CP, ACP) via electrostatic interactions, and coated lipids (DOTAP, DOPE, cholesterol, PEG2000-DSPE) on the ACP to form lipid-encapsulated, AuNPs-condensed CP (LACP). LACP can enter tumor cells and release CP into the cytosol by laser-triggered thermo-effects of the AuNPs; the CP can enter nuclei by TAT guidance, enabling effective knock-outs of target gene (Plk-1) of tumor (melanoma) and inhibition of the tumor both in vitro and in vivo. This AuNPs-condensed, lipid-encapsulated, and laser-controlled delivery system provides a versatile method for high efficiency CRISPR/Cas9 delivery and targeted gene editing for treatment of a wide spectrum of diseases.
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http://dx.doi.org/10.1002/anie.201708689DOI Listing
February 2018

Gold nanoclusters-assisted delivery of NGF siRNA for effective treatment of pancreatic cancer.

Nat Commun 2017 04 25;8:15130. Epub 2017 Apr 25.

Beijing Engineering Research Center for BioNanotechnology and CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for NanoScience and Technology, Beijing 100190, China.

Pancreatic cancer is one of the deadliest human cancers, whose progression is highly dependent on the nervous microenvironment. The suppression of gene expression of nerve growth factor (NGF) may have great potential in pancreatic cancer treatment. Here we show that gold nanocluster-assisted delivery of siRNA of NGF (GNC-siRNA) allows efficient NGF gene silencing and pancreatic cancer treatment. The GNC-siRNA complex increases the stability of siRNA in serum, prolongs the circulation lifetime of siRNA in blood and enhances the cellular uptake and tumour accumulation of siRNA. The GNC-siRNA complex potently downregulates the NGF expression in Panc-1 cells and in pancreatic tumours, and effectively inhibits the tumour progression in three pancreatic tumour models (subcutaneous model, orthotopic model and patient-derived xenograft model) without adverse effects. Our study constitutes a straightforward but effective approach to inhibit pancreatic cancer via NGF knockdown, suggesting a promising therapeutic direction for pancreatic cancer.
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http://dx.doi.org/10.1038/ncomms15130DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5414062PMC
April 2017

X-ray computed tomography imaging of a tumor with high sensitivity using gold nanoparticles conjugated to a cancer-specific antibody via polyethylene glycol chains on their surface.

Sci Technol Adv Mater 2016 26;17(1):387-397. Epub 2016 Jul 26.

Department of Nano-Medical Science, Graduate School of Medicine, Tohoku University, Sendai, Japan; Department of Surgical Oncology, Graduate School of Medicine, Tohoku University, Sendai, Japan.

Contrast agents are often used to enhance the contrast of X-ray computed tomography (CT) imaging of tumors to improve diagnostic accuracy. However, because the iodine-based contrast agents currently used in hospitals are of low molecular weight, the agent is rapidly excreted from the kidney or moves to extravascular tissues through the capillary vessels, depending on its concentration gradient. This leads to nonspecific enhancement of contrast images for tissues. Here, we created gold (Au) nanoparticles as a new contrast agent to specifically image tumors with CT using an enhanced permeability and retention (EPR) effect. Au has a higher X-ray absorption coefficient than does iodine. Au nanoparticles were supported with polyethylene glycol (PEG) chains on their surface to increase the blood retention and were conjugated with a cancer-specific antibody via terminal PEG chains. The developed Au nanoparticles were injected into tumor-bearing mice, and the distribution of Au was examined with CT imaging, transmission electron microscopy, and elemental analysis using inductively coupled plasma optical emission spectrometry. The results show that specific localization of the developed Au nanoparticles in the tumor is affected by a slight difference in particle size and enhanced by the conjugation of a specific antibody against the tumor.
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http://dx.doi.org/10.1080/14686996.2016.1194167DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5101864PMC
July 2016

Targeted tumor delivery and controlled release of neuronal drugs with ferritin nanoparticles to regulate pancreatic cancer progression.

J Control Release 2016 06 2;232:131-42. Epub 2016 Apr 2.

Beijing Engineering Research Center for BioNanotechnology, CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for NanoScience and Technology, Beijing 100190, China. Electronic address:

Pancreatic cancer is a lethal malignancy whose progression is highly dependent on the nervous microenvironment. This study develops neural drug-loaded ferritin nanoparticles (Ft NPs) to regulate the nervous microenvironment, in order to control the pancreatic cancer progression. The drug-loaded Ft NPs can target pancreatic tumors via passive targeting of EPR effects of tumors and active targeting via transferrin receptor 1 (TfR1) binding on cancer cells, with a triggered drug release in acidic tumor environment. Two drugs, one activates neural activity (carbachol), the other impairs neural activity (atropine), are encapsulated into the Ft NPs to form two kinds of nano drugs, Nano-Cab NPs and Nano-Ato NPs, respectively. The activation of the nervous microenvironment by Nano-Cab NPs significantly promotes the pancreatic tumor progression, whereas the blockage of neural niche by Nano-Ato NPs remarkably impairs the neurogenesis in tumors and the progression of pancreatic cancer. The Ft-based nanoparticles thus comprise an effective and safe route of delivery of neural drugs for novel anti-cancer therapy.
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http://dx.doi.org/10.1016/j.jconrel.2016.03.023DOI Listing
June 2016

An on-chip model for investigating the interaction between neurons and cancer cells.

Integr Biol (Camb) 2016 Mar;8(3):359-67

Beijing Engineering Research Center for BioNanotechnology, CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, National Center for NanoScience and Technology, Beijing 100190, China.

Emerging evidence suggests that there is extensive interaction between neurons and cancer cells. However, few model systems have been developed to investigate nerve-cancer cell interaction in vitro. Herein, a high-throughput microfluidic compartmentalized chip is developed to examine the interaction between neurons and cancer cells. The nerve bundles appear to provide a biophysical support for cancer cells and guide their directional migration. The cancers that have high levels of perineural invasion in clinical observations exhibit greater migration along neurites in the on-chip model. The on-chip model allows the screening of compounds which inhibit cancer cell migration along neurites in vitro. The interruption of neurites, the pharmacological blockade of nerve-cancer signaling, effectively attenuates the migration of cancer cells along neurites. This on-chip model provides a useful platform to investigate the dynamic interaction between cancer cells and neurons and can dramatically broaden the chemical space in screening neuron-related drugs for cancers.
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http://dx.doi.org/10.1039/c5ib00309aDOI Listing
March 2016

In vivo imaging of the molecular distribution of the VEGF receptor during angiogenesis in a mouse model of ischemia.

Blood 2011 Sep 5;118(13):e93-e100. Epub 2011 Aug 5.

Department of Nano-Medical Science, Graduate School of Medicine, Tohoku University, Sendai, Japan.

Vascular endothelial growth factor (VEGF) plays a critical role in angiogenesis and has been applied to medical therapy. However, because vascular imaging at the molecular level is impossible, the detailed in vivo dynamics of VEGF and its receptor (VEGFR) remain unknown. In this study, to understand the molecular distribution of VEGF and the VEGFR, we prepared ischemic mice with a new surgical method and induced angiogenesis in the gastrocnemius muscle. Then, we made a VEGF-conjugated fluorescence nanoparticle and performed staining of VEGFR-expressing cells with the fluorescent probe, demonstrating the high affinity of the probe for VEGFR. To observe the physiologic molecular distribution of VEGFR, we performed in vivo single-particle imaging of gastrocnemius in the ischemic leg with the fluorescent probe. The results suggested that only a 3-fold difference of VEGFR distribution is involved in the formation of branched vasculature in angiogenesis, although previous ex vivo data showed a 13-fold difference in its distribution, indicating that a method inducing a several-fold local increase of VEGFR concentration may be effective in generating site-specific angiogenesis in ischemic disease. This new in vivo imaging of ischemic mice could make useful contributions to understanding the mechanisms of angiogenesis and to developing a VEGFR-related drug.
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http://dx.doi.org/10.1182/blood-2010-12-322842DOI Listing
September 2011
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