Eye-tracking-based analysis of pharmacists' thought processes in the dispensing work: research related to the efficiency in dispensing based on right-brain thinking.

BACKGROUND: Pharmacists should be aware of their thought processes in dispensing work, including differences in the dispensing complexities owing to different drug positions in the left, center, and right areas. Dispensing errors associated with "same-name drugs (a pair of drugs with the same name but a different ingredient quantity)" are prevalent and often negatively affect patients. In this study, using five pairs of comparative models, the gaze movements of pharmacists in dispensing work were analyzed using an eye-tracking method to elucidate their thought processes. METHODS: We prepared verification slides and displayed them on a prescription monitor and three drug rack monitors. The dispensing information (drug name, drug usage, location display, and total amount) was displayed on a prescription monitor. A total of 180 drugs including five target drugs were displayed on the three drug rack monitors. Total gaze points in the prescription area, those in the drug rack area, total vertical movements between the two areas, and time required to dispense drugs were measured as the four classifications Gaze 1, Gaze 2, Passage, and Time, respectively. First, we defined the two types of location displays as "numeral combination" and "color/symbol combination." Next, we defined two pairs of models A1-A2 (numerals) and B1-B2 (color/symbol) to compare differences between the left and right areas. Moreover, three pairs of models C1-C2 (left), D1-D2 (center), and E1-E2 (right) were established to compare differences between "numeral combination" and "color/symbol combination." RESULTS: Significant differences in the complexities of dispensing work were observed in Gaze 2, Passage, and Time between the models A1-A2 (A1B2), and in Gaze 2 and Time between the models C1-C2, D1-D2, and E1-E2 (C1>C2, D1>D2, and E1>E2, respectively). CONCLUSIONS: Using the current dispensing rules, pharmacists are not good at dispensing drugs located in the right area. An effective measure for reducing the dispensing complexity is to introduce visual information in the prescription content; the utilization of the right brain facilitates reducing the complexity in the right dispensing area.

Contact-Killing Antibacterial Polystyrene Polymerized Using a Quaternized Cationic Initiator.

Contact-killing antibacterial materials are attracting attention owing to their ability for sustained antibacterial activity. However, contact-killing antibacterial polystyrene (PS) has not been extensively studied because its chemically stable structure impedes chemical modification. In this study, we developed an antibacterial PS sheet with a contact-killing surface using PS synthesized from 2,2'-azobis-[2-(1,3-dimethyl-4,5-dihydro-1H-imidazol-3-ium-2-yl)]propane triflate (ADIP) as a radical initiator with cationic moieties. The PS sheet synthesized with ADIP (ADIP-PS) exhibited antibacterial activity in contrast to PS synthesized with other azo radical initiators. Surface ζ-potential measurements revealed that only ADIP-PS had a cationic surface, which contributed to its contact-killing antibacterial activity. The ADIP-PS sheets also exhibited antibacterial activity after washing. In contrast, PS sheets containing silver, a typical leachable antibacterial agent, lost all antibacterial activity after the same washing treatment. The antibacterial ADIP-PS sheet demonstrated strong broad-spectrum activity against both Gram-positive and Gram-negative bacteria, including drug-resistant bacteria. Cytotoxicity tests using L929 cells showed that the ADIP-PS sheets were noncytotoxic. This contact-killing antibacterial PS synthesized with ADIP thus demonstrated good prospects as an easily producible antimicrobial material.

Profiles and Outcomes of Skin Injuries Caused by Injectable Drug Extravasation: An Analysis of the Japanese Adverse Drug Event Report Database.

Extravasation occurs when injectable drugs leak out of the blood vessels, damaging the surrounding tissues and causing a variety of skin injuries. This study aimed to comprehensively analyze extravasation risk, skin injury profiles, and outcomes for suspect drugs from the Japanese Adverse Drug Event Report (JADER) database. Adverse events were defined according to the Medical Dictionary for Regulatory Activities/Japanese version; the term extravasation (Standardized MedDRA Query Code: 20000136) was used in this analysis. The names of adverse events were entered as unified preferred terms and redefined to evaluate skin injury profiles. In addition, skin injury outcomes were divided into 2 broad categories: "improvement" and "no improvement." Reporting odds ratios were used to detect signals for adverse events. A total of 656 cases of extravasation-related adverse events were reported between April 2004 and January 2022. Signals for extravasation-related adverse events were detected from 11 drugs. Then, their respective skin injury profiles and outcomes were determined. These results suggest a relationship between adverse events associated with extravasation and 11 drugs and identify the characteristics of each skin injury and their outcomes. These findings will contribute to improving the quality of infusion management in clinical practice.

Measurement of Intracellular Temperature in Brown Adipocytes Using a Cationic Fluorescent Polymeric Thermometer.

Brown adipose tissue specializes in expending energy through non-shivering thermogenesis, and many studies have associated its activity with protection and treatment of obesity and metabolic diseases. To reveal the mechanisms involved in heat production, primary cultured brown adipose cells (BACs) have been used because of their ease of genetic engineering and similarity to living tissue. However, thermogenic activity has often been evaluated as an indirect method, such as the measurement of oxygen consumption. Recently, fluorescent nanothermometers for the direct measurement of intracellular temperature have been developed and applied to elucidate the mechanisms of heat production in BACs. In this chapter, we introduce a protocol that uses a cationic fluorescent polymeric thermometer to directly measure the temperature within primary cultured BACs. We anticipate that this protocol will be beneficial in elucidating the mechanism of thermogenesis in BACs.

Analysis of the thinking process of pharmacists in response to changes in the dispensing environment using the eye-tracking method.

BACKGROUND: Pharmacists must understand the mechanisms by which dispensing errors occur and take appropriate preventive measures. In this study, the gaze movements of pharmacists were analyzed using an eye-tracking method, to elucidate the thinking process of pharmacists when identifying target drugs and avoiding dispensing errors. METHODS: We prepared verification slides and projected them on a large screen. Each slide comprised a drug rack area and a prescription area; the former consisted of a grid-like layout with 55 drugs and the latter displayed dispensing information (drug name, drug usage, location number, and total amount). Twelve pharmacists participated in the study, and three single-type drugs and six double-type drugs were used as target drugs. We analyzed the pharmacists' method of identifying the target drugs, the mechanisms by which errors occurred, and the usefulness of drug photographs using the error-induction (-) /photo (+), error-induction (+) / (+), and error-induction (+) /photo (-) models. RESULTS: Visual invasion by non-target drugs was found to have an effect on the subsequent occurrence of dispensing errors. In addition, when using error-induction models, the rate of dispensing error was 2.8 and 11.1% for the photo (+) and photo (-) models, respectively. Furthermore, based on the analysis of eight pharmacists who dispensed drugs without errors, it was clear that additional confirmation of "drug name" was required to accurately identify the target drug in the photo (+) model; additionally, that of "location number" was required to pinpoint directly the position of target drug in the photo (-) model. CONCLUSIONS: By analyzing the gaze movements of pharmacists using the eye-tracking method, we clarified pharmacists' thinking process which was required to avoid dispensing errors in a complicated environment and proved the usefulness of drug photographs in terms of both reducing the complexity of the dispensing process and the risk of dispensing errors. Effective measures to prevent dispensing errors include ensuring non-adjacent placement of double-type drugs and utilization of their image information.

Surface Characteristics of Antibacterial Polystyrene Nanoparticles Synthesized Using Cationic Initiator and Comonomers.

Polymer nanoparticles have attracted attention as antibacterial materials, but the function of the polymer itself has not yet been clarified sufficiently. To estimate the essential surface properties of antibacterial polymer nanoparticles, herein, we synthesized cationic polystyrene (PSt) nanoparticles via soap-free emulsion polymerization using 2,2'-azobis-[2-(1,3-dimethyl-4,5-dihydro-1H-imidazol-3-ium-2-yl)]propane triflate (ADIP) as initiator. The conversion of total monomers was drastically increased through the addition of the commoner (vinylbenzyl)trimethylammonium chloride (VBTMAC), where unimodal size distributions (Cv ≤ 10%) were obtained at comonomer molar ratios between 0.0083 and 0.0323. The adsorption behavior of a solvatochromic anionic fluorescent dye revealed the surface charge density (σ) and affinity with anionic molecules (K) of PSt nanoparticles. The PSt nanoparticles with increased K values exhibited antibacterial activity against Staphylococcus epidermidis, with a minimum inhibitory concentration of at least 0.69 mg/mL. To determine a plausible mechanism for the antibacterial activity, the membrane damage induced by PSt nanoparticles was evaluated using an assay utilizing polydiacetylene vesicles as the model for negatively charged bilayer membranes. The PSt nanoparticles exhibiting large K values disturbed the bilayer structure of the model membrane system, suggesting that the synthesized PSt nanoparticles could be utilized as a contact-killing antibacterial agent.

Usefulness of Medication Guidance Sheets for Patients With Non-Hodgkin's Lymphoma Receiving ESHAP±R Therapy.

BACKGROUND/AIM: The occurrence of chemotherapy-related serious adverse events (AEs) is associated with a poor prognosis of hematopoietic malignancies. We have developed a medication guidance sheet (MGS) for monitoring AEs occurring when combining chemotherapy with etoposide, methylprednisolone, cisplatin, cytarabine, and rituximab (ESHAP±R). In this study, the usefulness of MGS was investigated in non-Hodgkin's lymphoma patients. PATIENTS AND METHODS: The MGS was used to monitor AEs in 48 adult patients receiving ESHAP±R. The prediction accuracy of the MGS was estimated before and after modification based on practical data. RESULTS: A total of 246 AEs developed, all of which were predicted by the MGS. Among them, 149 events (61%) occurred during the same period as those predicted by the MGS. After modification of MGS for the onset and duration of AEs, the accuracy increased to 84%. CONCLUSION: The accuracy of the original MGS for ESHAP±R was insufficient but greatly improved after the AEs duration modification.

Detection of overdose and underdose prescriptions-An unsupervised machine learning approach.

Overdose prescription errors sometimes cause serious life-threatening adverse drug events, while underdose errors lead to diminished therapeutic effects. Therefore, it is important to detect and prevent these errors. In the present study, we used the one-class support vector machine (OCSVM), one of the most common unsupervised machine learning algorithms for anomaly detection, to identify overdose and underdose prescriptions. We extracted prescription data from electronic health records in Kyushu University Hospital between January 1, 2014 and December 31, 2019. We constructed an OCSVM model for each of the 21 candidate drugs using three features: age, weight, and dose. Clinical overdose and underdose prescriptions, which were identified and rectified by pharmacists before administration, were collected. Synthetic overdose and underdose prescriptions were created using the maximum and minimum doses, defined by drug labels or the UpToDate database. We applied these prescription data to the OCSVM model and evaluated its detection performance. We also performed comparative analysis with other unsupervised outlier detection algorithms (local outlier factor, isolation forest, and robust covariance). Twenty-seven out of 31 clinical overdose and underdose prescriptions (87.1%) were detected as abnormal by the model. The constructed OCSVM models showed high performance for detecting synthetic overdose prescriptions (precision 0.986, recall 0.964, and F-measure 0.973) and synthetic underdose prescriptions (precision 0.980, recall 0.794, and F-measure 0.839). In comparative analysis, OCSVM showed the best performance. Our models detected the majority of clinical overdose and underdose prescriptions and demonstrated high performance in synthetic data analysis. OCSVM models, constructed using features such as age, weight, and dose, are useful for detecting overdose and underdose prescriptions.

Prognostic significance of pre-treatment ALBI grade in advanced non-small cell lung cancer receiving immune checkpoint therapy.

The liver is an essential organ for regulating innate and acquired immunity. We hypothesized that the pre-treatment hepatic function affects the clinical outcome of immune checkpoint inhibitors (ICIs) in non-small cell lung cancer (NSCLC). We analyzed 140 patients with NSCLC who received ICIs. We investigated the association between pre-treatment liver function, assessed using the albumin-bilirubin (ALBI) grade, and clinical outcomes in univariate, multivariate, and propensity score matching analyses. Patients were divided into four grades according to pre-treatment liver function. Eighty-eight patients had good hepatic reserve (ALBI grade 1 or 2a), whereas 52 patients had poor hepatic reserve (ALBI grade 2b or 3). In the univariate Kaplan-Meier analysis, the ALBI grade 1, 2a group had a significantly prolonged progression-free survival (PFS, 5.3 versus 2.5 months, p = 0.0019) and overall survival (OS, 19.6 vs. 6.2 months, p = 0.0002). These results were consistent, regardless of whether the analysis was performed in patients with a performance status of 0 or 1 at pre-treatment (N = 124) or in those selected using propensity score matching (N = 76). In the multivariate analysis, pre-treatment ALBI grade was an independent prognostic factor for both PFS (hazard ratio [HR] 0.57, 95% confidence interval [95% CI] 0.38-0.86, p = 0.007) and OS (HR 0.45, 95% CI 0.29-0.72, p = 0.001). Our results suggest that pre-treatment hepatic function assessed by ALBI grade could be an essential biomarker for predicting the efficacy of treatment with ICIs in NSCLC.

Continuous monitoring of neutrophils to lymphocytes ratio for estimating the onset, severity, and subsequent prognosis of immune related adverse events.

Immune checkpoint inhibitors (ICIs) play a central role in various cancers. ICIs can cause immune-related adverse events (irAEs). As severe irAEs can be life-threatening, biomarkers for estimating irAE onset are crucial. The neutrophils-to-lymphocytes ratio (NLR) reflects the systemic immune condition and known as a prognostic marker in ICI treatment. Our study evaluated if the NLR corresponded with irAEs, and its feasibility as a biomarker for irAE onset. We retrospectively analyzed 275 cancer patients treated with anti-PD-1 monotherapy. We observed 166 irAEs in 121 patients. The NLR was significantly elevated during irAEs. Patients experiencing interstitial pneumonitis showed NLR elevation 4 weeks before initial symptoms and diagnosis. Analyzing receiver operating characteristics curves revealed that elevated NLR distinguished subsequent pneumonitis severity with high accuracy (AUC 0.93, sensitivity 88.9%, specificity 88.2%, cut-off 2.37, p = 0.0004). After a severe irAE occurred, two NLR trends were observed. Patients who showed a prompt reduction in elevated NLRs had favorable progression-free survival (hazard ratio 0.32, 95% CI 0.10-1.01, p = 0.0140) and overall survival (hazard ratio 0.23, 95% CI 0.06-0.86, p = 0.0057) compared to the patients who maintained elevated NLRs. These findings suggest that continuous monitoring of NLR trends may predict irAE onset and severity and subsequent prognosis.

Usefulness of daily folic acid supplementation during methotrexate treatment of Japanese patients with rheumatoid arthritis.

OBJECTIVES: We investigated the effect of daily folic acid supplementation on methotrexate (MTX) toxicity and efficacy in Japanese patients with rheumatoid arthritis (RA). METHODS: We followed 19 patients treated with MTX who switched from taking weekly 5 mg folic acid supplementation (weekly regimen) to 1.25 mg daily (daily regimen). White blood cell (WBC) and platelet (PLT) counts, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels were collected for 24 weeks following the change. RESULTS: We observed no significant changes in WBC or PLT counts. AST and ALT levels, which had exceeded the upper limits of their normal ranges at the beginning of the study, were improved significantly at weeks 4 and 8, no subsequent deterioration in liver function was found. Further, no significant changes in ESR and CRP levels were observed. CONCLUSION: Our data indicate that supplementing 1.25 mg of folic acid daily rather than 5 mg weekly reduces toxicity caused by MTX without affecting its efficacy.

Risk Factors for Gemcitabine-Induced Vascular Pain in Patients With Pancreatic Cancer.

BACKGROUND: Peripheral intravenous injection of gemcitabine often causes vascular pain; however, preventive measures have not yet been established. OBJECTIVES: This study focused on identifying predictive factors for gemcitabine-induced vascular pain. METHODS: We retrospectively analyzed risk factors for developing vascular pain in patients with pancreatic cancer receiving gemcitabine infusions at our institution. Infusions were divided into groups according to presence or absence of vascular pain symptoms, and variables were compared. Odds ratios for risk factors were calculated using logistic regression analyses. RESULTS: Overall, 272 patients with pancreatic cancer were subjected to 725 gemcitabine infusions, and of these, 18.4% (n = 50) experienced vascular pain. There were significant differences in the gemcitabine dose (P = 0.025), dose of gemcitabine/body surface area (BSA; P = 0.004), concentration of gemcitabine (P = 0.025), and hot pack use (P = 0.011) between the vascular pain and no vascular pain groups. Multivariable analyses indicated that gemcitabine dose/BSA and lack of hot pack use were risk factors for developing vascular pain. Moreover, on administration of a higher dosage (>930 mg/m2), the incidence of vascular pain in patients using a hot pack (6.7%) was significantly lower than that in patients not provided a hot pack (16.2%). CONCLUSIONS AND RELEVANCE: High gemcitabine dosages and lack of hot pack use were predictive factors for gemcitabine-induced vascular pain in patients with pancreatic cancer. Patients receiving gemcitabine treatment should apply a hot pack to the injection site. Scrupulous clinical attention is required for patients presenting with these risk factors to improve pain management.

[Utility of the Filter Extraction Method for Detecting Anticancer Drug Contamination in Air].

The filter extraction method is a new, simple method for evaluating anticancer drug contamination in air. The method involves installing a filter in the exhaust port of an exhaust duct on a facility's air conditioner, then collecting and measuring fine particles of the antineoplastic agents adsorbed onto the filter. In this study, we analyzed the utility of maintaining continuous filter extraction for measuring cyclophosphamide and 5-fluorouracil contamination. The filters were installed in 3 areas of an outpatient chemotherapy room and then left in place for approximately 5 months. Results revealed the presence of cyclophosphamide and 5-fluorouracil in all 3 areas. However, the amounts and ratios of detected drugs differed among survey sites; this may have been caused by factors such as drug preparation, administration, and excretion. We conclude that the filter extraction method can be used continuously for monitoring anticancer drug contamination in air; thus, it can be utilized to monitor healthcare workers' occupational exposure to inhaled anticancer drugs. Indeed, the filter extraction method may be useful as a novel environmental monitoring technique.

[Significant Changes Associated with the Transition from Outsourcing to In-hospital Therapeutic Drug Monitoring of Novel Antiepileptics].

For many of the novel antiepileptics, immunoassays, used for routine therapeutic drug monitoring (TDM), cannot be used. We could monitor eight novel antiepileptics using an LC/MS method since July 2017. The purpose of this study was to evaluate the significant changes associated with the transition from outsourcing to in-hospital monitoring of novel antiepileptics. The number of measurements of novel antiepileptics was significantly increased during the first (p<0.01) and second (p<0.001) years of in-hospital monitoring as compared to that one year prior to in-hospital monitoring which was outsourced. The proportion of measurements of novel antiepileptics to all antiepileptics was 19.7%, 31.1%, and 38.4% during outsourcing, and first, and second years of in-hospital monitoring, respectively. The measurement cost was significantly reduced during the first (p<0.001) and second (p<0.001) years of in-hospital monitoring as compared to that during outsourcing. In addition, the revenue from TDM of antiepileptic drugs was significantly increased during the first (p<0.05) and second (p<0.01) years of in-hospital monitoring as compared with that during outsourcing. In conclusion, the switch from outsourcing to in-hospital monitoring led to an increase in the number of orders, a reduction in the measurement-related expenses of novel antiepileptics, and an increase in the revenue from TDM of antiepileptic drugs, which could promote the proper use of novel antiepileptics through TDM.

Effects of Diluent Volume and Administration Time on the Incidence of Anaphylaxis Following Docetaxel Therapy in Breast Cancer.

Hypersensitivity reactions, including anaphylaxis, are common side effects associated with docetaxel treatment in breast cancer patients. However, preventive measures have not yet been established. In this study, we retrospectively analyzed the risk factors for developing anaphylaxis in 182 female breast cancer patients treated with docetaxel. We found that 6.6% of all patients (n = 12) experienced anaphylaxis. Multivariate analyses indicated that concentration of docetaxel higher than 0.275 mg/m2/mL, docetaxel dose rate higher than 1.15 mg/m2/min, and white blood cell count less than 4290 cells/mL are risk factors for developing docetaxel-related anaphylaxis. In particular, concentrations of docetaxel or doses per administration time were associated with a high odds ratio (11.88 or 11.60) for docetaxel-related anaphylaxis. Moreover, patients receiving doses in 250 mL volume experienced anaphylaxis more frequently than those receiving doses in 500 mL (7.0 vs. 0.9%, p = 0.0236). Additionally, patients receiving treatments over 60 min tended to experience anaphylaxis more frequently than those who were treated over 90 min (6.7 vs. 1.1%, p = 0.0637). The present results indicate that high docetaxel concentrations, high dose rates, and low white blood cell counts are risk factors for developing docetaxel-related anaphylaxis, and administering docetaxel diluted in 500 mL over 90 min may limit docetaxel-induced hypersensitivity reactions.

Increasing Diluent Volume Decreases Bendamustine-Induced Venous Irritation without Reducing the Therapeutic Efficacy.

The intravenous injection of bendamustine often induces venous irritation, which reduces patients' QOL. We previously reported that the dilution of the final volume of bendamustine from 250 to 500 mL significantly decreased the incidence of venous irritation. However, the influence of this change on the therapeutic efficacy of bendamustine remains unclear. Therefore, the aim of this study was to evaluate the efficacy and safety profiles of bendamustine at different dilutions of the final volume, comparing with the correspondences of previous studies. Thirty-four patients, who received a total of 161 courses of bendamustine and rituximab chemotherapy, were included in this study. The overall response rate of this regimen was 94.1% in this study, which was comparable to that reported in the BRB study (94.2%, a phase II study of bendamustine plus rituximab therapy in Japanese patients). Additionally, the median progression-free survival was not inferior to that reported in the BRB study. Bendamustine-induced venous irritation was observed in 17.6% of the patients during the first treatment cycle administered at a final volume of 500 mL, and was found to be lower than that observed in the control, where bendamustine was administered at a final volume of 250 mL (85.7%). These results suggest that diluting bendamustine to 500 mL, but not to 250 mL, reduces the incidence of venous irritation without a negative impact on its therapeutic efficacy; thus, this simple strategy may be beneficial to ensure efficacy and safety in patients receiving regimens including bendamustine.

A Cell-Targeted Non-Cytotoxic Fluorescent Nanogel Thermometer Created with an Imidazolium-Containing Cationic Radical Initiator.

A cationic fluorescent nanogel thermometer based on thermo-responsive N-isopropylacrylamide and environment-sensitive benzothiadiazole was developed with a new azo compound bearing imidazolium rings as the first cationic radical initiator. This cationic fluorescent nanogel thermometer showed an excellent ability to enter live mammalian cells in a short incubation period (10 min), a high sensitivity to temperature variations in live cells (temperature resolution of 0.02-0.84 °C in the range 20-40 °C), and remarkable non-cytotoxicity, which permitted ordinary cell proliferation and even differentiation of primary cultured cells.

Enhancement of immunomodulative effect of lactic acid bacteria on plasmacytoid dendritic cells with sucrose palmitate.

Plasmacytoid dendritic cells (pDCs) play a key role in the immune response against viruses. In addition, recent research has suggested that pDCs possess direct and indirect tumoricidal activities. We previously found that a lactic acid bacteria strain, Lactococcus lactis JCM 5805 (LC-Plasma), stimulated pDCs and prevented viral infection in mouse and human studies. Meanwhile, emulsifiers have recently been highlighted as candidate adjuvants for some viral vaccines and cancer immunotherapies. In this study, we discovered some specific emulsifiers, mainly consisting of sucrose fatty acid esters, that drastically enhance the potency of LC-Plasma to activate pDCs in vitro. The emulsifiers promoted the efficient uptake of LC-Plasma by pDCs and the ratio of pDCs that took up LC-Plasma correlated with the activity of pDCs. In addition, an in vivo study showed that oral treatment with LC-Plasma mixed with an emulsifier induced a higher expression of genes related to anti-viral immunity in the lung compared to treatment with LC-Plasma alone. Both LC-Plasma and the emulsifiers used in this study have been confirmed to be safe for human use. Therefore, LC-Plasma mixed with an emulsifier might be a useful tool for certain anti-cancer and anti-viral therapies.

Difference in intracellular temperature rise between matured and precursor brown adipocytes in response to uncoupler and ß-adrenergic agonist stimuli.

Brown adipocytes function to maintain body temperature by heat production. However, direct measurement of heat production at a single cell level remains difficult. Here we developed a method to measure the temperature within primary cultured brown adipocytes using a cationic fluorescent polymeric thermometer. Placement of the thermometer within a matured brown adipocyte and a precursor cell enabled the detection of heat production following uncoupler treatment. The increase in the intracellular temperature due to stimulation with a mitochondrial uncoupler was higher in matured brown adipocytes than in precursor cells. Stimulation with a ß-adrenergic receptor (ß-AR) agonist, norepinephrine, raised the intracellular temperature of matured brown adipocytes to a level comparable to that observed after stimulation with a ß3-AR-specific agonist, CL316.243. In contrast, neither ß-AR agonist induced an intracellular temperature increase in precursor cells. Further, pretreatment of brown adipocytes with a ß3-AR antagonist inhibited the norepinephrine-stimulated elevation of temperature. These results demonstrate that our novel method successfully determined the difference in intracellular temperature increase between matured brown adipocytes and precursor cells in response to stimulation by an uncoupler and ß-AR agonists.

Intracellular temperature measurements with fluorescent polymeric thermometers.

In 2003, we successfully created the first fluorescent polymeric thermometer by combining a thermo-responsive polymer and an environment-sensitive (polarity and hydrogen bonding-sensitive) fluorophore. Its high sensitivity to temperature variation and high hydrophilicity, even under conditions of high ionic strength, enabled intracellular temperature measurements. Along with the progress of our research projects, the development of new luminescent molecular thermometers and the establishment of novel methods for measuring intracellular temperature have matured in this field. In this Feature Article, we summarize the background and history of intracellular temperature measurements using fluorescent polymeric thermometers based on studies performed in our laboratory and the relationship between our methods and those of other eminent research groups. Future research directions regarding intracellular temperature measurements are also discussed.