Photothermal Modulation of Dynamic Covalent Poly(ethylene glycol)/PEDOT Composite Hydrogels for On-Demand Drug Delivery.

Hydrogels are cross-linked three-dimensional polymer networks that have tissue-like properties. Dynamic covalent bonds (DCB) can be utilized as hydrogel cross-links to impart injectability, self-healing ability, and stimuli responsiveness to these materials. In our research, we utilized dynamic thiol-Michael bonds as cross-links in poly(ethylene glycol) (PEG)-based hydrogels. Because the equilibrium of the reversible, exothermic thiol-Michael reaction can be modulated by temperature, we investigated the possibility of using thermal and photothermal stimuli to modulate the gel-to-sol transition of these materials with the aim of developing an on-demand pulsatile cargo release system. For this purpose, we incorporated poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles within the hydrogel to facilitate photothermal modulation using near-infrared light. PEDOT nanoparticles of 50 nm in diameter and with strong near-infrared absorption were prepared by oxidative emulsion polymerization. We then used Michael addition of thiol-ene pairs from 4-arm PEG-thiol (PEG-SH) and 4-arm PEG-benzylcyanoacetamide (PEG-BCA) to form dynamically cross-linked hydrogels. PEDOT nanoparticles were entrapped in situ to form Gel/PEDOT composites. Rheology and inverted tube test studies showed that the gel-to-sol transition occurred at 45-50 °C for 5 wt % gels and that this transition could be tailored by varying the wt % of the polymer precursors. The hydrogels were found to be capable of self-healing and being injected with a clinically relevant injection force. Bovine serum albumin-fluorescein isothiocyanate (BSA-FITC), a fluorescently labeled protein, was then loaded into the Gel/PEDOT as a therapeutic mimic. Increased release of BSA-FITC upon direct thermal stimulation and photothermal stimulation with an 808 nm laser was observed. Pulsatile release of BSA-FITC over seven cycles was demonstrated. MTS and live-dead assays demonstrated that Gel/PEDOT was cytocompatible in MDA-MB-231 breast cancer and 3T3 fibroblast cell lines. Further studies demonstrated that the encapsulation and laser-triggered release of the chemotherapeutic agent doxorubicin (DOX) could also be achieved. Altogether, this work advances our understanding of the temperature-dependent behavior of a dynamic covalent hydrogel, Gel/PEDOT, and leverages that understanding for application as a photothermally responsive biomaterial for controlled release.

Sex-Differences and Associations Between Complement Activation and Synovial Vascularization in Patients with Late-Stage Knee Osteoarthritis.

Purpose: Synovial inflammation in knee osteoarthritis (OA) causes disorganized synovial angiogenesis and complement activation in synovial fluid, but links between complement and synovial microvascular pathology have not been established. Since complement causes vascular pathology in other diseases and since sex-differences exist in complement activation and in OA, we investigated sex differences in synovial fluid complement factors, synovial tissue vascular pathology, and associations between complement and synovial vascular pathology in patients with late-stage knee OA. Methods: Patients with symptomatic, late-stage radiographic knee OA undergoing total knee arthroplasty or high tibial osteotomy provided matched synovial fluid and tissue biopsies during surgery. Complement factors (C2, C5, adipsin, MBL, and CFI) and terminal complement complex (sC5b-C9) were measured in synovial fluid by multiplex or enzyme-linked immunosorbent assay, respectively. Features of synovial vascular pathology (vascularization, perivascular edema, and vasculopathy) were assessed by histopathology. Multivariate linear regression models were used to assess associations between synovial fluid complement factors and histopathological features of vascular pathology, with adjustment for age, sex, body mass index, and sex interaction. Sex-disaggregated comparisons were completed. Results: Synovial fluid biomarker and histopathology data were included from 97 patients. Most synovial fluid complement factors and synovial tissue histopathological features were similar between sexes. Synovial fluid C5 trended to lower levels in males (-20.93 ng/mL [95%CI -42.08, 0.23] p=0.05). Median vasculopathy scores (0.42 [95%CI 0.07, 0.77] p=0.02) were higher in males. In the full cohort, C5 concentration was associated with lower vascularization scores (-0.005 [95%CI -0.010, -0.0001] p=0.04) while accounting for sex*C5 interaction. In sex-disaggregated analyses, increased C5 concentration was associated with lower vascularization scores (-0.005 [95%CI -0.009, -0.0001] p=0.04) in male patients, but not in female patients. Males had higher sC5b-C9 compared to females. Additionally, males with high C5 had a higher synovial fluid concentration of sC5b-C9 compared to males with low C5. No differences were found in females. Conclusion: Higher synovial fluid C5 levels were associated with increased complement activation and decreased synovial vascularization in males but not in females with OA. Future studies should test whether synovial fluid complement activation suppresses synovial angiogenesis and identify mechanisms accounting for C5-related sex-differences in synovial fluid complement activation in patients with knee OA.

Patient engagement study to identify and improve surgical experience.

BACKGROUND: Patient engagement is the establishment of active partnerships between patients, families, and health professionals to improve healthcare delivery. The objective of this project was to conduct a series of patient engagement workshops to identify areas to improve the surgical experience and develop strategies to address areas identified as high priority. METHODS: Faculty surgeons and patients were invited to participate in three in-person meetings. Evaluation included identifying and developing strategies for three priority areas to improve the surgical experience and level of engagement achieved at each meeting. RESULTS: Sixteen faculty surgeons and 32 patients participated. Some 63 themes to improve the surgical experience were identified; the three highest-priority themes were physician communication, discharge process, and expectations at home after discharge. Individual improvement strategies for these three prioritized themes (12, 36 and 6 respectively) were used to develop a formal strategic plan, and included a physician communication survey, discharge process worksheet and video, and guideline regarding what to expect at home after discharge. Overall, the level of engagement achieved was considered high by over 85 per cent of the participants. CONCLUSION: A high level of patient engagement was achieved. Priorities were identified with patients and surgeons to improve surgical experience, and strategies were developed to address these areas.

Whole Brain Radiotherapy Versus Stereotactic Radiosurgery in Poor-Prognosis Patients with One to 10 Brain Metastases: A Randomised Feasibility Study.

AIMS: A significant proportion of patients with brain metastases have a poor prognosis, with a life expectancy of 3-6 months. To determine the optimal radiotherapeutic strategy for brain metastases in this population, we conducted a randomised feasibility study of whole brain radiotherapy (WBRT) versus stereotactic radiosurgery (SRS). MATERIALS AND METHODS: Patients with a life expectancy of 3-6 months and between one and 10 brain metastases with a diameter ≤4 cm were enrolled at six Canadian cancer centres. Patients were randomly assigned (1:1) to receive either WBRT (20 Gy in five fractions) or SRS (15 Gy in one fraction). The primary end point was the rate of accrual per month. Secondary feasibility and clinical end points included the ratio of accrued subjects to screened subjects. This trial is registered with ClinicalTrials.gov (number NCT02220491). RESULTS: In total, 210 patients were screened to enrol 22 patients into the trial; 20 patients were randomised between the two arms. Two patients did not receive treatment because one patient died and another patient withdrew consent after being enrolled. Patients were accrued between January 2015 and November 2017; the accrual rate was 0.63 patients/month. The most common reasons for exclusion were anticipated median survival outside the required range (n = 40), baseline Karnofsky Performance Score below 70 (n = 28) and more than 10 brain metastases (n = 28). The median follow-up was 7.0 months and the median survival was 7.0 months for all patients in the trial. The median intracranial progression-free survival was 1.8 months in the SRS arm and 9.2 months in the WBRT arm. There were five grade 3+ toxicities in the SRS arm and one grade 3+ toxicity in the WBRT arm; no grade 5 toxicities were observed. The cumulative rates of retreatment were 40% in the SRS arm and 40% in the WBRT arm. CONCLUSIONS: A randomised trial evaluating WBRT versus SRS in patients with one to 10 metastases and a poor prognosis is feasible. A slower than expected accrual rate and difficulties with accurate prognostication were identified as issues in this feasibility study. A larger phase III randomised trial is planned to determine the optimal treatment in this patient population.

The pancreas-specific form of secretory pathway calcium ATPase 2 regulates multiple pathways involved in calcium homeostasis.

Acinar cell exocytosis requires spatiotemporal Ca2+ signals regulated through endoplasmic reticulum (ER) stores, Ca2+ATPases, and store-operated Ca2+ entry (SOCE). The secretory pathway Ca2+ATPase 2 (SPCA2) interacts with Orai1, which is involved in SOCE and store independent Ca2+ entry (SICE). However, in the pancreas, only a C-terminally truncated form of SPCA2 (termed SPAC2C) exists. The goal of this study was to determine if SPCA2C effects Ca2+ homeostasis in a similar fashion to the full-length SPCA2. Using epitope-tagged SPCA2C (SPCA2CFLAG) expressed in HEK293A cells and Fura2 imaging, cytosolic [Ca2+] was examined during SICE, SOCE and secretagogue-stimulated signaling. Exogenous SPCA2C expression increased resting cytosolic [Ca2+], Ca2+ release in response to carbachol, ER Ca2+ stores, and store-mediated and independent Ca2+ influx. Co-IP detected Orai1-SPCA2C interaction, which was altered by co-expression of STIM1. Importantly, SPCA2C's effects on store-mediated Ca2+ entry were independent of Orai1. These findings indicate SPCA2C influences Ca2+ homeostasis through multiple mechanisms, some of which are independent of Orai1, suggesting novel and possibly cell-specific Ca2+ regulation.

Employment outcomes for recent Canadian radiation oncology graduates.

Introduction: Radiation oncology (ro) is one of several specialties identified by the Royal College of Physicians and Surgeons of Canada with employment difficulties for graduating trainees. The purpose of the present study was to determine the employment status and location of recent Canadian ro trainees within 2 years after graduation, to monitor workforce recruitment trends over time, and to capture the opinions of program directors about employment difficulty for graduates and resident morale. Visa trainee graduates were excluded. Methods: Results of the survey administered to ro program directors in 2016 and again in 2018, both with 100% response rates, are presented here. Results: In both surveys, approximately 57% of ro graduates had attained staff or locum employment in Canada or abroad within 2 years from graduation (p = 0.92). However, graduates with Canadian staff employment increased by 46% to 32 in 2018 from 22 in 2016, while the proportion of graduates with staff positions abroad decreased to 6% from 27% (p = 0.04). Most trainees without staff positions were employed as fellows. The proportion of program directors reporting employment difficulties for graduates in the Canadian labour market declined to 38% from 85% (p = 0.04), and the morale of residents in training programs remained high. Conclusions: Employment challenges for newly certified Canadian-trained radiation oncologists continue. However, compared with the situation 2 years ago, trends in the Canadian ro job market suggest a modest improvement, with more staff employment in Canada and lower emigration rates for jobs abroad.

A Case Report Describing the Use of Point of Care Ultrasound to Guide Successful Cardiopulmonary Resuscitation After Unanticipated Arrest in Ambulatory Surgery.

We present a case of a 41-year-old man who suffered cardiac arrest after induction of general anesthesia for an ambulatory ophthalmologic procedure. In this report, we highlight the use of focused transthoracic echocardiography by the anesthesia team to guide a prolonged resuscitation. Emergency room and critical care physicians have described the use of focused echocardiography to aid in diagnosing correctible causes of cardiac arrest, predicting outcomes, and in decision making regarding termination of resuscitation. We discuss benefits and barriers to anesthesiologists incorporating focused cardiac ultrasound into the perioperative arena.

Fundamental Factors Impacting the Stability of Phosphonate-Derivatized Ruthenium Polypyridyl Sensitizers Adsorbed on Metal Oxide Surfaces.

A series of 18 ruthenium(II) polypyridyl complexes were synthesized and evaluated under electrochemically oxidative conditions, which generates the Ru(III) oxidation state and mimics the harsh conditions experienced during the kinetically limited regime that can occur in dye-sensitized solar cells (DSSCs) and dye-sensitized photo-electrosynthesis cells, to further develop fundamental insights into the factors governing molecular sensitizer surface stability in aqueous 0.1 M HClO4. Both desorption and oxidatively induced ligand substitution were observed on planar fluorine-doped tin oxide (FTO) electrodes, with a dependence on the E1/2 Ru(III/II) redox potential dictating the comparative ratios of the processes. Complexes such as RuP4OMe ( E1/2 = 0.91 vs Ag/AgCl) displayed virtually only desorption, while complexes such as RuPbpz ( E1/2 > 1.62 V vs Ag/AgCl) displayed only chemical decomposition. Comparing isomers of 4,4'- and 5,5'-disubstituted-2,2'-bipyridine ancillary ligands, a dramatic increase in the rate of desorption of the Ru(III) complexes was observed for the 5,5'-ligands. Nanoscopic indium-doped tin oxide thin films (nanoITO) were also sensitized and analyzed with cyclic voltammetry, UV-vis absorption spectroscopy, and X-ray photoelectron spectroscopy, allowing for further distinction of desorption versus ligand-substitution processes. Desorption loss to bulk solution associated with the planar surface of FTO is essentially non-existent on nanoITO, where both desorption and ligand substitution are shut down with RuP4OMe. These results revealed that minimizing time spent in the oxidized form, incorporating electron-donating groups, maximizing hydrophobicity, and minimizing molecular bulk near the adsorbed ligand are critical to optimizing the performance of ruthenium(II) polypyridyl complexes in dye-sensitized devices.

Who Is to Blame? Framing HPV to Influence Vaccination Intentions among College Students.

Human papillomavirus (HPV) is a prevalent sexually transmitted infection (STI) among college students. Although previous research has studied HPV-related health communication strategies using various framing techniques, the goal of this study is to test how two unique message frames-whether mentioning HPV as an STI and whether to attribute the cause of infection as external or internal-would influence young adults' intentions to receive the recommended HPV vaccine. Results indicate that gender and causal attribution framing influenced participants' intentions to receive the HPV vaccine.

Ready to Go Home? Patients' Experiences of the Discharge Process in an Enhanced Recovery After Surgery (ERAS) Program for Colorectal Surgery.

BACKGROUND: With the adoption of enhanced recovery after surgery (ERAS) programs, patients are being discharged earlier and require more post-discharge teaching, educational materials, and information. OBJECTIVE: The purpose of this study is to assess satisfaction, discharge needs, and follow-up concerns of patients within an ERAS implementation program (iERAS). METHODS: Between 2012 and 2015, the iERAS program was undertaken at an academic hospital where 554 patients having elective colorectal surgery were enrolled. After discharge, patients were sent a survey containing multiple choice questions, preference ranking, and open-ended questions. Free-text responses were analyzed through a thematic approach. RESULTS: Overall, 496 patients were mailed surveys and 219 (44.2%) completed the survey. Ninety-three percent were satisfied with the discharge information, and 90% felt they were ready for discharge. Eighty-six percent of patients saw their surgeon at 6 weeks, and 88% were satisfied with this follow-up plan. Some patients felt they had inadequate post-operative information, including how to resolve complications while at home and lack of reliable information for common post-operative occurrences. Patients with ostomies wanted more information about what to expect post-discharge and what symptoms were normal. Support from the homecare team and having a surgical nurse available were considered to be essential. CONCLUSIONS: Improved post-operative education for surgical patients prior to discharge within iERAS is required to facilitate patient-centered discharge planning. Such interventions may help decrease unplanned hospital visits during the immediate post-discharge period.

Maropitant administered orally 2-2.5 h prior to morphine and dexmedetomidine reduces the incidence of emesis in cats.

Objectives The main goal of this study was to test the antiemetic effects of maropitant administered orally 2-2.5 h prior to morphine and dexmedetomidine in cats. Methods Eighty-three healthy female cats were randomized to receive maropitant (8 mg orally; n = 39) or no treatment (control; n = 44), 2-2.5 h prior to morphine 0.1 mg/kg and dexmedetomidine 20 µg/kg intramuscularly. The incidence of sialorrhea, lip licking, retching and vomiting were recorded after morphine/dexmedetomidine injection. Results There were no differences between groups in terms of age or weight. The treated group received a mean ± SD dose of maropitant of 2.9 ± 0.6 mg/kg. The incidence of sialorrhea and lip licking was no different between groups. The incidence of retching (control 36% vs maropitant 13%; P = 0.012) and emesis (control 32% vs maropitant 13%; P = 0.03) was significantly reduced in cats treated with maropitant. Conclusions and relevance Maropitant 8 mg (total dose) administered orally 2-2.5 h prior to morphine and dexmedetomidine significantly reduced, but did not eliminate, the incidences of retching and vomiting. Maropitant did not decrease the occurrence of sialorrhea and lip licking, signs that may be indicative of nausea. Maropitant might be useful for morning administration to prevent emesis in outpatient cats requiring sedation or anesthesia; however, dose regimens or interval of administration might require improvement.

The Silver Lining of Shame: Framing HPV to Influence Vaccination Intentions.

College students suffer disproportionately from human papillomavirus (HPV), a sexually transmitted infection (STI) that could result in genital warts or cancers in both males and females. Research contends that stigma and shame may serve as barriers to disclosure intentions, as well as vaccination intentions. The goal of this study was to examine whether two framing strategies-whether to mention that HPV is sexually transmitted and whether to highlight the cause of infection as internal or external-would influence young adults' intentions to disclose a potential diagnosis and their intentions to get the recommended HPV vaccine. Results indicate that STI framing and gender had consistent impacts on disclosure and vaccination intentions. Further, causal attribution framing also influenced participants' intention to get the vaccine at no cost immediately and their intention to get the vaccine at the retail price of $375 in the future. Theoretical and practical implications of these results are discussed.

Two-Mechanism Model for the Interaction of Etoposide Quinone with Topoisomerase IIα.

Topoisomerase II is an essential nuclear enzyme involved in regulating DNA topology to facilitate replication and cell division. Disruption of topoisomerase II function by chemotherapeutic agents is in use as an effective strategy to fight cancer. Etoposide is an anticancer therapeutic that disrupts the catalytic cycle of topoisomerase II and stabilizes enzyme-bound DNA strand breaks. Etoposide is metabolized into several species including active quinone and catechol metabolites. Our previous studies have explored some of the details of how these compounds act against topoisomerase II. In our present study, we extend those analyses by examining several effects of etoposide quinone on topoisomerase IIα including whether the quinone impacts ATP hydrolysis, DNA ligation, cleavage complex persistence, and enzyme/DNA binding. Our results demonstrate that the quinone inhibits relaxation at 100-fold lower levels of drug when compared to that of etoposide. Further, the quinone inhibits ATP hydrolysis by topoisomerase IIα. The quinone does appear to stabilize single-strand breaks similar to etoposide suggesting a traditional poisoning mechanism. However, there is minimal difference in cleavage complex persistence in the presence of etoposide or etoposide quinone. In contrast to etoposide, we find that etoposide quinone blocks enzyme/DNA binding, which provides an explanation for previous data showing the ability of the quinone to inactivate the enzyme over time. Finally, etoposide quinone is able to stabilize the N-terminal protein clamp implying an interaction between the compound and this portion of the enzyme. Taken together, the evidence supports a two-mechanism model for the effect of the quinone on topoisomerase II: (1) interfacial poison and (2) covalent poison that interacts with the N-terminal clamp and impacts the binding of DNA.

Evaluation of oral maropitant as an antiemetic in cats receiving morphine and dexmedetomidine.

Objectives The aim of the study was to evaluate the antiemetic effects of maropitant, after oral administration, in cats receiving morphine and dexmedetomidine. Methods This prospective, blinded, randomized controlled trial involved 98 healthy female domestic shorthair cats. Cats were randomly assigned to receive maropitant PO 8 mg total (group M) administered 18 h prior to sedation with intramuscular dexmedetomidine 20 µg/kg and morphine 0.1 mg/kg, or no antiemetic treatment (group C). The occurrence of signs of nausea (sialorrhea and lip-licking), retching and emesis during the 30 mins following administration of dexmedetomidine and morphine was measured for each group. Results Two cats were excluded from the investigation. Cats in group M (n = 46) received an average of 2.5 mg/kg of maropitant PO. Compared with group C (n = 50), cats in group M had lower incidences of emesis (M: 4% vs C: 40%), retching (M: 8% vs C: 40%) and lip-licking (M: 30% vs C: 52%) (all P <0.05). The incidence of sialorrhea was not different between groups (M: 21% vs C: 22%). Conclusions and relevance Maropitant 8 mg total PO was effective in reducing morphine and dexmedetomidine-induced emesis by 10-fold, when administered as early as 18 h in advance to healthy cats. Maropitant PO could be useful for administration the evening prior to a scheduled procedure requiring sedation/anesthesia to decrease the incidence of emesis.

Activated Notch counteracts Ikaros tumor suppression in mouse and human T-cell acute lymphoblastic leukemia.

Activating NOTCH1 mutations occur in ~60% of human T-cell acute lymphoblastic leukemias (T-ALLs), and mutations disrupting the transcription factor IKZF1 (IKAROS) occur in ~5% of cases. To investigate the regulatory interplay between these driver genes, we have used a novel transgenic RNA interference mouse model to produce primary T-ALLs driven by reversible Ikaros knockdown. Restoring endogenous Ikaros expression in established T-ALL in vivo acutely represses Notch1 and its oncogenic target genes including Myc, and in multiple primary leukemias causes disease regression. In contrast, leukemias expressing high levels of endogenous or engineered forms of activated intracellular Notch1 (ICN1) resembling those found in human T-ALL rapidly relapse following Ikaros restoration, indicating that ICN1 functionally antagonizes Ikaros in established disease. Furthermore, we find that IKAROS mRNA expression is significantly reduced in a cohort of primary human T-ALL patient samples with activating NOTCH1/FBXW7 mutations, but is upregulated upon acute inhibition of aberrant NOTCH signaling across a panel of human T-ALL cell lines. These results demonstrate for the first time that aberrant NOTCH activity compromises IKAROS function in mouse and human T-ALL, and provide a potential explanation for the relative infrequency of IKAROS gene mutations in human T-ALL.

The discoloration of the Taj Mahal due to particulate carbon and dust deposition.

The white marble domes of the Taj Mahal are iconic images of India that attract millions of visitors every year. Over the past several decades the outer marble surfaces of the Taj Mahal have begun to discolor with time and must be painstakingly cleaned every several years. Although it has been generally believed that the discoloration is in some way linked with poor air quality in the Agra region, the specific components of air pollution responsible have yet to be identified. With this in mind, ambient particulate matter (PM) samples were collected over a one-year period and found to contain relatively high concentrations of light absorbing particles that could potentially discolor the Taj Mahal marble surfaces, that include black carbon (BC), light absorbing organic carbon (brown carbon, BrC), and dust. Analyses of particles deposited to marble surrogate surfaces at the Taj Mahal indicate that a large fraction of the outer Taj Mahal surfaces are covered with particles that contain both carbonaceous components and dust. We have developed a novel approach that estimates the impact of these deposited particles on the visible light surface reflectance, which is in turn used to estimate the perceived color by the human eye. Results indicate that deposited light absorbing dust and carbonaceous particles (both BC and BrC from the combustion of fossil fuels and biomass) are responsible for the surface discoloration of the Taj Mahal. Overall, the results suggest that the deposition of light absorbing particulate matter in regions of high aerosol loading are not only influencing cultural heritage but also the aesthetics of both natural and urban surfaces.

Oxidative stress and inflammation response following aerobic exercise: role of ethnicity.

African-Americans are at a significantly greater risk for developing several diseases and conditions. These conditions often have underlying oxidative stress mechanisms. Therefore the purpose of this investigation was to ascertain the post-exercise oxidative response to a single bout of aerobic exercise in African-American and Caucasian college-age females. A total of 10 African-American and 10 Caucasian females completed the study. Each subject had her VO2 max measured while exercising on a treadmill. A week later, each subject returned to the laboratory and performed a 30-min run at 70% of her VO2max. Blood samples were taken immediately prior to and following exercise for analysis. Lipid hydroperoxides, protein carbonyls, malondialdehyde, xanthine oxidase, glutathione in the reduced (GSH) and oxidized (GSSG) forms, TNFα and interleukin 6 were measured from blood taken before and after exercise. Significance was set at p≤0.05 a priori. Xanthine oxidase was the only measure that did not significantly increase following exercise. All other markers showed a significant elevation in response to the exercise bout with no difference between groups except that the Caucasian group had significantly higher malondialdehyde post-exercise compared to the African-American group. This cohort of college-age African-American and Caucasian females showed little difference in their response to a single 30-min run at 70% of their max in the markers of oxidative stress within the blood.

The proapoptotic BH3-only proteins Bim and Puma are downstream of endoplasmic reticulum and mitochondrial oxidative stress in pancreatic islets in response to glucotoxicity.

Apoptosis of pancreatic beta cells is a feature of type 2 diabetes and its prevention may have therapeutic benefit. High glucose concentrations induce apoptosis of islet cells, and this requires the proapoptotic Bcl-2 homology domain 3 (BH3)-only proteins Bim and Puma. We studied the stress pathways induced by glucotoxicity in beta cells that result in apoptosis. High concentrations of glucose or ribose increased expression of the transcription factor CHOP (C/EBP homologous protein) but not endoplasmic reticulum (ER) chaperones, indicating activation of proapoptotic ER stress signaling. Inhibition of ER stress prevented ribose-induced upregulation of Chop and Puma mRNA, and partially protected islets from glucotoxicity. Loss of Bim or Puma partially protected islets from the canonical ER stressor thapsigargin. The antioxidant N-acetyl-cysteine also partially protected islets from glucotoxicity. Islets deficient in both Bim and Puma, but not Bim or Puma alone, were significantly protected from killing induced by the mitochondrial reactive oxygen species donor rotenone. Our data demonstrate that high concentrations of glucose induce ER and oxidative stress, which causes cell death mediated by Bim and Puma. We observed significantly higher Bim and Puma mRNA in islets of human donors with type 2 diabetes. This indicates that inhibition of Bim and Puma, or their inducers, may prevent beta-cell destruction in type 2 diabetes.