[18F]FB(ePEG12)12-exendin-4 noninvasive imaging of insulinoma negative for insulin immunostaining on specimen from endoscopic ultrasonography-guided fine needle aspiration: a case report with review of literature.

Insulinomas are the most common functional pancreatic neuroendocrine neoplasm; when treatment is delayed, they induce hyperinsulinemic hypoglycemia, which is life-threatening. As surgical resection is the only curative treatment for insulinoma, preoperative localization is crucial; however, localization based on conventional imaging modalities such as computed tomography (CT) and magnetic resonance imaging is often inconclusive. Somatostatin receptor-targeted imaging is another option for detecting pancreatic neuroendocrine neoplasms but has low sensitivity and is not specific for insulinoma. The clinical application of other localizing approaches such as selective arterial calcium stimulation and endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) is limited by their being invasive and/or technically complex. Moreover, an EUS-FNA specimen of an insulinoma may be negative on insulin immunostaining. Thus, a noninvasive and clinically practical insulinoma-specific diagnostic tool to discriminate insulinomas with high accuracy is anticipated. Glucagon-like peptide-1 receptor (GLP-1R)-targeted imaging has emerged in the effort to fulfill this need. We recently developed the novel fluorine-18-labeled exendin-4-based probe conjugated with polyethylene glycol, [18F]FB(ePEG12)12-exendin-4 (18F-exendin-4) for positron emission tomography (PET) imaging and reported its clinical benefit in a case of insulinoma in the pancreatic tail. We report here a case of insulinoma in the pancreatic head in which an EUS-FNA specimen was negative on insulin immunostaining while precise preoperative localization and conclusive evidence for curative enucleation was provided by 18F-exendin-4 PET/CT (Japan Registry of Clinical Trials; jRCTs051200156).

Resilience and coping styles in family caregivers of terminally ill patients: A cross-sectional survey.

OBJECTIVES: Coping styles can be improved by dyadic palliative care interventions and may alleviate patients' and family caregivers' distress. Moreover, family caregivers' preloss resilience protects against depression after bereavement. This study aimed to determine the types of coping styles can be encouraged to increase resilience. METHODS: A self-reported questionnaire survey was administered to family caregivers at the 4 palliative care units, and their resilience was assessed using the Connor-Davidson Resilience Scale (CD-RISC) and their coping styles were assessed using the Brief Coping Orientation to Problem Experienced, as well as their background characteristics. RESULTS: Among 291 caregivers with a mean CD-RISC score of 56.2 (standard deviation: 16.13), internal locus of control, educational level, and history of psychotropic drug use were associated with resilience. After adjusting for the aforementioned factors, more frequent use of positive coping styles such as active coping (Spearman's ρ = 0.29), acceptance (ρ = 0.29), positive reframing (ρ = 0.29), planning (ρ = 0.24), and humor (ρ = 0.18), was found to be associated with higher resilience. On the contrary, more frequent use of negative coping styles such as behavioral disengagement (ρ = -0.38), self-blame (ρ = -0.27), and denial (ρ = -0.14) was found to be associated with less resilience. SIGNIFICANCE OF RESULTS: By assessing internal locus of control, educational level, and history of psychotropic medication use of family caregivers, as factors associated with their respective resilience, may help identify less resilient family caregivers who are at risk for developing major depression after bereavement. In addition, coping skill-based educational interventions targeting patients and their family caregivers that focus on specific coping styles associated with resilience may increase family caregivers' resilience, resulting in less emotional distress and a lower risk of major depression after bereavement.

Changes in depressive symptoms among family caregivers of patients with cancer after bereavement and their association with resilience: A prospective cohort study.

OBJECTIVES: To elucidate changes in depressive symptoms after bereavement and the impact of pre-loss resilience on such changes and on the extent of complicated grief and posttraumatic growth. METHODS: Prospective cohort surveys were provided to family caregivers of patients with cancer in four palliative care units (PCUs) before and after bereavement. Pre-loss Connor-Davidson Resilience Scale scores, pre- and post-loss Patient Health Questionnaire-9 scores, post-loss Brief Grief Questionnaire scores, and the expanded Posttraumatic Growth Inventory scores were determined. RESULTS: Out of 186 bereaved family caregivers, 71 (38.2%) responses were analyzed, among which 47% pre-loss and 15% post-loss responses suggested to be a high risk for major depressive disorder (MDD). Approximately 90% of family caregivers at a high risk for post-loss MDD were already at a high risk for pre-loss MDD. Even after adjustment of the background variables as covariates, the interaction effect between family caregivers' pre-loss depressive symptoms and resilience on post-loss depressive symptoms was observed (F = 7.29; p < 0.01). Moreover, pre-loss resilience was not associated with other bereavement outcome measures. CONCLUSIONS: Among family caregivers of patients with cancer in PCUs, 47% and 15% had high risk for MDD before and after bereavement, respectively. Moreover, pre-loss resilience mitigated post-loss depressive symptoms among family caregivers who had high risk for MDD before bereavement. However, considering the study's small sample size, further research is needed.

Comorbid insomnia among breast cancer survivors and its prediction using machine learning: a nationwide study in Japan.

OBJECTIVE: Insomnia is an increasingly recognized major symptom of breast cancer which can seriously disrupt the quality of life during and many years after treatment. Sleep problems have also been linked with survival in women with breast cancer. The aims of this study were to estimate the prevalence of insomnia in breast cancers survivors, clarify the clinical characteristics of their sleep difficulties and use machine learning techniques to explore clinical insights. METHODS: Our analysis of data, obtained in a nationwide questionnaire survey of breast cancer survivors in Japan, revealed a prevalence of suspected insomnia of 37.5%. With the clinical data obtained, we then used machine learning algorithms to develop a classifier that predicts comorbid insomnia. The performance of the prediction model was evaluated using 8-fold cross-validation. RESULTS: When using optimal hyperparameters, the L2 penalized logistic regression model and the XGBoost model provided predictive accuracy of 71.5 and 70.6% for the presence of suspected insomnia, with areas under the curve of 0.76 and 0.75, respectively. Population segments with high risk of insomnia were also extracted using the RuleFit algorithm. We found that cancer-related fatigue is a predictor of insomnia in breast cancer survivors. CONCLUSIONS: The high prevalence of sleep problems and its link with mortality warrants routine screening. Our novel predictive model using a machine learning approach offers clinically important insights for the early detection of comorbid insomnia and intervention in breast cancer survivors.

Oncology care providers' awareness and practice related to physical activity promotion for breast cancer survivors and barriers and facilitators to such promotion: a nationwide cross-sectional web-based survey.

PURPOSE: A known barrier to getting breast cancer survivors (BCSs) to engage in habitual exercise is a lack of information on recommended physical activity levels provided to them by oncology care providers (OCPs). However, the actual situation in Japan remains unclear. This study sought to clarify OCPs' awareness and practice related to Japan's physical activity recommendation for BCSs and to ascertain barriers to routine information provision. METHODS: We conducted a web-based survey involving members of the Japanese Breast Cancer Society (JBCS) and the Japanese Association of Cancer Rehabilitation between Dec. 2018 and Feb. 2019. RESULTS: Of 10,830 members, 1,029 (9.5%) responded. Only 19.1% were aware of the details of the JBCS physical activity recommendation, and only 21.2% routinely provided physical activity information to BCSs. Factors related to being aware of the recommendation details were 1) availability of the guidelines, 2) experience reading relevant parts of the guidelines, and 3) involvement in multidisciplinary team case meetings. Barriers to routine information provision were 1) absence of perceived work responsibility, 2) underestimation of survivors' needs, 3) lack of resources, 4) lack of self-efficacy about the recommendation, and 5) poor knowledge of the recommendation. CONCLUSIONS: Only one fifth of the OCPs routinely provided physical activity information. Barriers to provision were poor awareness, self-efficacy, and attitudes and unavailable resources. The physical activity recommendation needs to be disseminated to all OCPs and an information delivery system needs to be established for BCSs to receive appropriate information and support to promote their engagement in habitual physical activity.

[68Ga-DOTATOC PET/CT for Diagnosing Neuroendocrine Tumors].

Lutathera is a peptide receptor radionuclide therapy (PRRT) for neuroendocrine tumors and was approved as the first PRRT drug in Japan in 2021. Although neuroendocrine tumors are often less aggressive than other highly malignant and invasive tumors, there have been few effective therapy options, so "Lutathera"is a long-awaited treatment. Lutathera is indicated for the treatment of "somatostatin receptor-positive neuroendocrine tumors". Currently, in Japan, the only imaging method to evaluate the expression of somatostatin receptors in lesions is scintigraphy using In-111 pentetreotide(OctreoScan). In this section, we would like to introduce the current status of the 68Ga-DOTA-SSA PET/CT using somatostatin analogue(SSA)in our institution.

Modulation of the Pharmacokinetics of a Radioligand Targeting Carbonic Anhydrase-IX with Albumin-Binding Moieties.

The expression of carbonic anhydrase-IX (CA-IX) in tumors can lead to a poor prognosis; thus, CA-IX has attracted much attention as a target molecule for cancer diagnosis and treatment. An 111In-labeled imidazothiadiazole sulfonamide (IS) derivative, [111In]In-DO3A-IS1, exhibited marked tumor accumulation but also marked renal accumulation, raising concerns about it producing a low signal/background ratio and a high radiation burden on the kidneys. In this study, four 111In-labeled IS derivatives, IS-[111In]In-DO2A-ALB1-4, which contained four different kinds of albumin binder (ALB) moieties, were designed and synthesized with the aim of improving the pharmacokinetics of [111In]In-DO3A-IS1. Their utility for imaging tumors that strongly express CA-IX was evaluated in mice. An in vitro binding assay of cells that strongly expressed CA-IX (HT-29 cells) was performed using acetazolamide as a competitor against CA-IX, and IS-[111In]In-DO2A-ALB1-4 did not exhibit reduced binding to HT-29 cells compared with [111In]In-DO3A-IS1. In contrast, IS-[111In]In-DO2A-ALB1-4 showed a greater ability to bind to human serum albumin than [111In]In-DO3A-IS1 in vitro. In an in vivo biodistribution study, the introduction of an ALB moiety into the 111In-labeled IS derivative markedly decreased renal accumulation and increased HT-29 tumor accumulation and blood retention. The pharmacokinetics of the IS derivatives varied depending on the substituted group within the ALB moiety. Single-photon emission computed tomography imaging with IS-[111In]In-DO2A-ALB1, which showed the highest tumor/kidney ratio in the biodistribution study, facilitated clear HT-29 tumor imaging, and no strong signals were observed in the normal organs. These results indicate that IS-[111In]In-DO2A-ALB1 may be an effective CA-IX imaging probe and that the introduction of ALB moieties may improve the pharmacokinetics of CA-IX ligands.

Synthesis and biological evaluation of novel 18F-labeled phenylbenzofuran-2-carboxamide derivative for detection of orexin 1 receptor in the brain.

Although the orexin 1 receptor (OX1R) in the brain is considered to regulate reward and feeding, the in vivo function of OX1R has not been fully elucidated. In vivo imaging of OX1R with positron emission tomography (PET) may be useful to further understand the molecular details of OX1R. In this study, we newly designed and synthesized a phenylbenzofuran-2-carboxamide (PBC) derivative ([18F]PBC-1) and evaluated its utility as a PET probe targeting OX1R in the brain. The results of cell binding assays suggested that [18F]PBC-1 has affinity for OX1R. In an in vitro competitive inhibition assay, PBC-1 showed selective binding affinity for OX1R (IC50 = 19.5 nM) over orexin 2 receptor (IC50 = 456.7 nM). Furthermore, [18F]PBC-1 displayed sufficient brain uptake for in vivo imaging with PET in a biodistribution study using normal mice, but in vivo instability was observed. These results suggest that further modifications for improvement of the pharmacokinetics are needed, but the PBC scaffold has potential for the development of useful PET probes targeting OX1R in the brain.

Development of Novel PET Imaging Probes for Detection of Amylin Aggregates in the Pancreas.

The deposition of islet amyloid is associated with ß-cell mass dysfunction in type 2 diabetes mellitus (T2DM). Since the amylin aggregate is the main component of islet amyloid, in vivo imaging of amylin may be useful for diagnosis and elucidation of the pathogenic mechanism of T2DM. In the present study, we newly designed, synthesized, and evaluated two 18F labeled compounds ([18F]DANIR-F 2b and [18F]DANIR-F 2c) as positron emission tomography (PET) probes targeting amylin aggregates. In an in vitro binding study, DANIR-F 2b and DANIR-F 2c showed binding affinity for amylin aggregates (Ki = 160 and 29 nM, respectively). In addition, [18F]DANIR-F 2b and [18F]DANIR-F 2c clearly labeled islet amyloids in in vitro autoradiography of T2DM pancreatic sections. In the biodistribution study using normal mice, [18F]DANIR-F 2b and [18F]DANIR-F 2c displayed favorable pharamacokinetics in the pancreas and some organs located near the pancreas. Furthermore, in an ex vivo autoradiographic study, [18F]DANIR-F 2c also bound to amylin aggregates in the pancreas of the amylin transplanted mice. The results of this study suggest that [18F]DANIR-F 2c shows fundamental properties as a PET imaging probe targeting amylin aggregates in the T2DM pancreas.

Synthesis and evaluation of novel technetium-99m-hydroxamamide complex based on imidazothiadiazole sulfonamide targeting carbonic anhydrase-IX for tumor imaging.

Carbonic anhydrase-IX (CA-IX) is an attractive target for detecting tumors associated with a poor prognosis. We previously reported a [99mTc]hydroxamamide complex based on ureidosulfonamide as a CA-IX ligand ([99mTc]URB2A), which showed a favorable affinity for CA-IX high-expressing cells in vitro and tumors in vivo; however, radioactivity retention in the blood pool suggested a high background signal on imaging. To improve the pharmacokinetics of [99mTc]URB2A, in this study, we designed and synthesized [99mTc]ISB2 based on imidazothiadiazole sulfonamide, which exhibited greater CA-IX affinity and faster clearance from the blood pool than ureidosulfonamide in studies using corresponding 111In-labeled compounds, and evaluated its utility for CA-IX imaging. In an in vitro cell binding assay, [99mTc]ISB2 markedly bound to CA-IX high-expressing (HT-29) cells; moreover, its binding was greater than that of [99mTc]URB2A. In an in vivo biodistribution assay, [99mTc]ISB2 showed faster clearance from the blood pool than [99mTc]URB2A; however, lower HT-29 tumor accumulation was observed. Further structural modification of [99mTc]ISB2 to improve its stability may lead to the development of a useful [99mTc]hydroxamamide complex for CA-IX imaging.

Synthesis and evaluation of indium-111-labeled imidazothiadiazole sulfonamide derivative for single photon emission computed tomography imaging targeting carbonic anhydrase-IX.

Carbonic anhydrase-IX (CA-IX) is a zinc enzyme overexpressed in the hypoxic regions of many types of solid tumors; therefore, in vivo imaging of CA-IX may contribute to cancer diagnosis. In this study, we newly designed and synthesized an 111In-labeled CA-IX imaging agent based on an imidazothiadiazole sulfonamide (IS) scaffold conjugated with a chelating moiety, DO3A ([111In]DO3A-IS1), and evaluated its utility for imaging of CA-IX high-expressing tumors. [111In]DO3A-IS1 was successfully synthesized at a 76% radiochemical yield by reacting its precursor with 111InCl3 in acetate buffer. In in vitro assays, [111In]DO3A-IS1 showed marked stability in murine plasma and greater binding to CA-IX high-expressing (HT-29) cells (118 ± 21% initial dose/mg protein) than CA-IX low-expressing (MDA-MB-231) cells (1.4 ± 0.3% initial dose/mg protein). Moreover, in an in vivo biodistribution assay, [111In]DO3A-IS1 showed marked accumulation in the HT-29 tumor (8.71 ± 1.41% injected dose/g at 24 h postinjection). In addition, in a single photon emission computed tomography (SPECT) study, [111In]DO3A-IS1 clearly and selectively visualized the HT-29 tumor as compared with the MDA-MB-231 tumor. These results indicate that [111In]DO3A-IS1 may serve as a useful SPECT imaging agent with the novel scaffold targeting CA-IX.

Synthesis and biological evaluation of radioiodinated 3-phenylcoumarin derivatives targeting myelin in multiple sclerosis.

Myelin is a lipid multilayer involved in the rate of nerve transmission, and its loss is a pathological feature of multiple sclerosis in brains. Since in vivo imaging of myelin may be useful for drug development, early diagnosis, and monitoring the disease stage, we designed, synthesized, and evaluated eight novel radioiodinated 3-phenylcoumarin derivatives as imaging probes targeting myelin. In the biodistribution study using normal mice, all compounds displayed sufficient brain uptake, ranging from 2.5 to 5.0% ID/g, at 2 min postinjection. On ex vivo autoradiography, [125I]18 and [125I]21, which have a dimethylamino group, showed high binding affinity for myelin in the normal mouse brain. In addition, the radioactivity accumulation of [125I]21 in the white matter of the spinal cord in the experimental autoimmune encephalomyelitis mice was lower than that in naive mice. These results suggest that [123I]21 shows potential as a single photon emission computed tomography probe targeting myelin.

Development of Gold Nanorods Conjugated with Radiolabeled Anti-human Epidermal Growth Factor Receptor 2 (HER2) Monoclonal Antibody as Single-Photon Emission Computed Tomography/Photoacoustic Dual-Imaging Probes Targeting HER2-Positive Tumors.

Surgery remains one of the main treatments of cancer and both precise pre- and intraoperative diagnoses are crucial in order to guide the operation. We consider that using an identical probe for both pre- and intra-operative diagnoses would bridge the gap between surgical planning and image-guided resection. Therefore, in this study, we developed gold nanorods (AuNRs) conjugated with radiolabeled anti-human epidermal growth factor receptor 2 (HER2) monoclonal antibody, and investigated their feasibility as novel HER2-targeted dual-imaging probes for both single photon emission computed tomography (SPECT) (preoperative diagnosis) and photoacoustic (PA) imaging (intraoperative diagnosis). To achieve the purpose, AuNRs conjugated with different amount of trastuzumab (Tra) were prepared, and Tra-AuNRs were labeled with indium-111. After the evaluation of binding affinity to HER2, cell binding assay and biodistribution studies were carried out for optimization. AuNRs with moderate trastuzumab conjugation (Tra2-AuNRs) were proposed as the novel probe and demonstrated significantly higher accumulation in NCI-N87 (HER2 high-expression) tumors than in SUIT2 (low-expression) tumors 96 h post-injection along with good affinity towards HER2. Thereafter, in vitro PA imaging and in vivo SPECT imaging studies were performed. In in vitro PA imaging, Tra2-AuNRs-treated N87 cells exhibited significant PA signal increase than SUIT2 cells. In in vivo SPECT, signal increase in N87 tumors was more notable than that in SUIT2 tumors. Herein, we report that the Tra2-AuNRs enabled HER2-specific imaging, suggesting the potential as a robust HER2-targeted SPECT and PA dual-imaging probe.

Initial evaluation of PET/CT with 18 F-FSU-880 targeting prostate-specific membrane antigen in prostate cancer patients.

This first-in-man study was carried out to evaluate the safety, whole-body distribution, dose estimation, and lesion accumulation of 18 F-FSU-880, a newly developed probe targeting prostate-specific membrane antigen. Six prostate cancer patients with known metastatic lesions underwent serial whole-body PET/computed tomography (CT) with 18 F-FSU-880. Blood and urine were analyzed before and after PET/CT. Accumulation of 18 F-FSU-880 in organs and metastatic lesions in serial PET images were evaluated by measuring the standardized uptake values. From the biodistribution data, the organ doses and whole-body effective dose were calculated using OLINDA/EXM software was developed by Dr. Michael Stabin of Vanderbilt University, Nashville, Tennessee, USA. 18 F-FSU-880 PET/CT could be carried out without significant adverse effects. High physiological uptake was observed in the salivary/lachrymal glands and kidneys. The effective dose was calculated to be 0.921 × 10-2 mSv/MBq. Known metastatic lesions were clearly visualized with high image contrast that increased with time, except in 1 patient, whose bone metastases were well-controlled and inactive. The PET/CT with 18 F-FSU-880 could be carried out safely and could clearly visualize active metastatic lesions. The present results warrant further clinical studies with a larger number of cases to verify the clinical utility of 18 F-FSU-880 PET/CT in the management of prostate cancer patients.

Clinical utility of 68Ga-DOTATOC positron emission tomography/computed tomography for recurrent renal cell carcinoma.

PURPOSE: Positron emission tomography (PET)/computed tomography (CT) with 68Ga-labelled 1,4,7,10-tetraazacyclododecane-N,N',N″,N″'-tetraacetic acid-D-Phe1-Tyr3-octreotide (DOTATOC) has been accepted as a diagnostic imaging tool especially for patients with neuroendocrine tumours. However, its clinical usefulness for restaging of renal cell carcinoma (RCC) has not been fully investigated. This retrospective study was performed to elucidate the clinical value of PET/CT using 68Ga-DOTATOC in patients with known or suspected recurrent RCC. METHODS: We analysed 25 consecutive patients who underwent DOTATOC-PET/CT scans after surgery for RCC (23 clear cell, 1 papillary, 1 unclassified). PET/CT findings were reviewed and the detection rate was calculated on a patient and lesion basis. The detectability was compared in patients who also underwent PET/CT scans with 18F-fluorodeoxyglucose (FDG). Histopathological findings or clinical follow-up were used as the reference standard. RESULTS: Based on the final diagnosis, 76 recurrent or metastatic lesions were confirmed in this population. Of these lesions, 66 lesions in 22 patients were positive by DOTATOC-PET/CT. The patient-based and lesion-based sensitivity was 88% (22/25) and 87% (66/76), respectively. Twelve patients underwent both DOTATOC-PET/CT and FDG-PET/CT. The lesion-based sensitivity of DOTATOC was 74% (20/27), while that of FDG was 59% (16/27). Eight lesions were identified only by DOTATOC, but four lesions from papillary RCC were detected only by FDG. CONCLUSION: Our data indicate that DOTATOC-PET/CT would be useful for detecting recurrent foci in patients with clear cell RCC. DOTATOC-PET/CT and FDG-PET/CT are considered to have complementary roles.

Development of the 99mTc-Hydroxamamide Complex as a Probe Targeting Carbonic Anhydrase IX.

Carbonic anhydrase IX (CA-IX) is regarded as a favorable target for in vivo imaging because of its specific expression in hypoxic regions of tumors. Hypoxia assists tumor propagation and growth and is resistant to chemotherapy and radiotherapy. Here, we designed and synthesized [99mTc]hydroxamamide ([99mTc]Ham) and [99mTc]methyl-substituted-hydroxamamide ([99mTc]MHam) complexes including a bivalent CA-IX ligand, sulfonamide (SA), and ureidosulfonamide (UR). In a cell binding assay, [99mTc]Ham complexes with bivalent SA ([99mTc]SAB2A and [99mTc]SAB2B) and UR ([99mTc]URB2A and [99mTc]URB2B) showed significantly greater uptake into CA-IX high-expressing (HT-29) cells than that into CA-IX low-expressing cells. Since the binding affinity of [99mTc]URB2A and [99mTc]URB2B for CA-IX was significantly higher than that of [99mTc]SAB2A and [99mTc]SAB2B, we additionally synthesized [99mTc]MURB2 (a [99mTc]MHam complex with bivalent UR) and evaluated the CA-IX-specific binding affinity of [99mTc]URB2A, [99mTc]URB2B, and [99mTc]MURB2. Their uptake into HT-29 cells was reduced by the addition of a CA inhibitor, acetazolamide, suggesting their CA-IX-specific binding affinity. A biodistribution study in HT-29 tumor-bearing mice was carried out using [99mTc]URB2A and [99mTc]MURB2 with the highest specificity for HT-29 cells. [99mTc]URB2A showed moderate tumor uptake and reduction by coinjection with acetazolamide; however, the tumor/blood ratio was insufficient for in vivo imaging. These results provided key information for the design of novel Ham-based imaging probes targeting CA-IX.

Increased 14C-acetate accumulation in IDH-mutated human glioblastoma: implications for detecting IDH-mutated glioblastoma with 11C-acetate PET imaging.

PURPOSE: Recently, the potential value of isocitrate dehydrogenase (IDH) mutation as a prognostic marker in glioblastomas has been established. Glioblastomas are classified by their IDH mutation status under the 2016 WHO classification system. However, noninvasive diagnostic methods for the mutation status in glioblastoma patients have not been established so far. The purpose of this study was to evaluate the difference of acetate metabolism between in glioblastomas with wild-type IDH and in those with IDH mutation by comparing the uptake of 14C-acetate using genetically engineered glioblastoma cell lines in vitro and in vivo. METHODS: We established glioblastoma cells (U251) expressing IDH1 R132H and examined the cell uptake of [1-14C]acetate. Biodistribution studies and an autoradiographic study for U251 cell tumor-bearing mice (BALB/c-nu/nu) with or without the IDH1 mutation were performed 1 h after [1-14C]acetate administration. RESULTS: Significantly higher uptake of [1-14C]acetate was observed in U251/IDH1 R132H cells than in U251/IDH1 wild-type cells both in vitro (10.11 ± 0.94 vs. 4.26 ± 0.95%dose/mg, p = 0.0047) and in vivo (0.97 ± 0.14 vs. 0.66 ± 0.05%ID/g; p = 0.0037). Tumor-to-muscle ratios were also significantly higher in U251/IDH1 R132H tumors (3.36 ± 0.41 vs. 1.88 ± 0.59, p = 0.0030). The autoradiographic study shows the entirely higher radioactivity of the U251/IDH1 R132H tumor tissue section than that of the U251/IDH1 Wild-type tumor. CONCLUSIONS: In vitro and in vivo studies demonstrated that the uptake of radiolabeled acetate was significantly higher in IDH-mutated cells than in IDH-wild-type cells.

Synthesis and biological evaluation of F-18 labeled tetrahydroisoquinoline derivatives targeting orexin 1 receptor.

Orexin 1 receptor (OX1R) is thought to be involved in various body functions, including arousal maintenance and emotional control, but the full details of its function remain unknown. OX1R imaging with positron emission tomography (PET) would be useful in elucidating the orexin system including OX1R, but no PET probes targeting OX1R have been reported. We, therefore, designed and synthesized tetrahydroisoquinoline (THIQ) derivatives as novel PET probes targeting OX1R, and evaluated their utility. In an in vitro competitive binding assay, THIQ-1 and THIQ-2 showed significantly higher binding to OX1R (IC50 = 30 and 31 nM, respectively) than OX2R (IC50 = 160 and 332 nM, respectively). These features were also observed in a cell binding assay using [18F]THIQ-1 and [18F]THIQ-2, demonstrating their OX1R-specific binding property in vitro. In a biodistribution study using normal mice, the brain uptake of [18F]THIQ-1 was higher than that of [18F]THIQ-2, but further improvement is required for in vivo imaging with PET. Taken together, [18F]THIQ-1 and [18F]THIQ-2 have the potential to become useful imaging probes for PET targeting the OX1R, but require additional structural changes to improve their brain uptake.

18F-labeled benzimidazopyridine derivatives for PET imaging of tau pathology in Alzheimer's disease.

Hyperphosphorylated tau proteins are one of the neuropathological hallmarks in the Alzheimer's disease (AD) brain. The in vivo imaging of tau aggregates with nuclear medical imaging probes is helpful for the further comprehension of and medical intervention in the AD pathology. For tau-selective PET imaging, we newly designed and synthesized 18F-labeled benzimidazopyridine (BIP) derivatives with fluoroalkylamino groups, [18F]IBIPF1 and [18F]IBIPF2, and evaluated their utilities as tau imaging probes. They both bound selectively to tau against amyloid ß (Aß) aggregates in AD brain sections in vitro, and showed good pharmacokinetics in mouse brains in vivo. Notably, [18F]IBIPF1 exhibited high tau-selectivity (Tau/Aß ratio = 34.8), high brain uptake (6.22% ID/g at 2 min postinjection), and subsequent washout (2.77% ID/g at 30 min postinjection). In vivo analysis of radiometabolites indicated that [18F]IBIPF1 was stable against metabolism in the mouse brain. These encouraging preclinical results suggest that further structural optimization based on the BIP scaffold may lead to the development of more useful tau imaging probes.

Expectations of and recommendations for a cancer survivorship guideline in Japan: a literature review of guidelines for cancer survivorship.

BACKGROUND: Optimal cancer survivorship care needs its comprehensive guidelines. We aimed to identify English and Japanese guidelines that include cancer survivorship in their title, the issues highlighted in such guidelines, and any existing oncology practice guidelines in Japan that address these issues. METHODS: This literature review was performed in three stages. First, guidelines published in English or Japanese that included cancer survivorship in the title were identified. Then, the issues that each cancer survivorship guideline addressed were defined. Lastly, Japanese guidelines that include survivorship issues were sought. RESULTS: Six guidelines published in English addressed 31 cancer survivorship issues. No specific cancer survivorship guideline was available in Japanese. Thirty-four Japanese guidelines mentioned cancer survivorship issues. These guidelines addressed screening/surveillance for detecting recurrence or secondary cancer but did not address coordination of care, implications for practice, or inclusion of family. At present, Japanese guidelines poorly address the issue of promotion of a healthy lifestyle in cancer survivors. Also, poorly addressed were long-term and late effects such as pain, psychological distress, fatigue, cognitive dysfunction, cardiovascular effects (including anthracycline-induced cardiac toxicity), sleep disorders, and sexual dysfunction in cancer survivors. CONCLUSION: There is a need for guidelines on optimal coordination of care between oncologists and other health care providers to support patients along the cancer care continuum and specifically to encourage a healthy lifestyle as part of cancer survivorship. The development of a comprehensive Japanese guideline that addresses these issues would help to improve the clinical outcome for cancer survivors in Japan.