Chronic MK-801 administration provokes persistent deficits in social memory in the prairie vole (Microtus ochrogaster): A potential animal model for social deficits of schizophrenia.

The prairie vole (Microtus ochrogaster) is a rodent species that has been used extensively to study biological aspects of human social bonding. Nevertheless, this species has not been studied in the context of modeling social deficits characteristic of schizophrenia. Building on studies in rodents that show that sub-chronic administration of an NMDA receptor antagonist induces persistent behavioral and neurological characteristics of schizophrenia, we administered MK-801 (0.2 mg/kg, daily, for 7 days) or physiological saline to young adult (45 days old) virgin male voles. At 69 days of age, we paired these males with virgin females. 24 h later, we assessed the males' social investigation of each female across the first 5 min of a three-hour preference test, and side-by-side contact with each female during the last hour of the test. Unlike saline-treated males, MK-801-treated males did not preferentially investigate the unfamiliar female, indicating a deficit in social memory. Although males of both groups preferentially spent time with their female partner, regression analysis revealed that deficits in social memory predicted lower partner preference in MK-801-treated males. We interpret these results in the context of recent studies of the natural history of the prairie vole as well as in the context of cognitive deficits in schizophrenia and propose that the social component of episodic memory might influence an individual's capacity to form and maintain long-term social bonds.

Patient and Oncology Nurse Preferences for the Treatment Options in Advanced Melanoma: A Discrete Choice Experiment.

BACKGROUND: Understanding the perceptions of patients and oncology nurses about the relative importance of benefits and risks associated with newer treatments of advanced melanoma can help to inform clinical decision-making. OBJECTIVES: The aims of this study were to quantify and compare the views of patients and oncology nurses regarding the importance of attributes of treatments of advanced melanoma. METHODS: A discrete choice experiment (DCE) was conducted in US-based oncology nurses and patients diagnosed with advanced melanoma. Patients and nurses were enlisted through online panels. In a series of scenarios, respondents had to choose between 2 hypothetical treatments, each with 7 attributes: mode of administration (MoA), dosing schedule (DS), median duration of therapy (DoT), objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and grade 3 or 4 adverse events (AEs). Hierarchical Bayesian logistic regression models were used to estimate preference weights. RESULTS: A total of 200 patients with advanced melanoma and 150 oncology nurses participated. The relative importance estimates of attributes by patients and nurses, respectively, were as follows: OS, 33% and 28%; AEs, 29% and 26%; ORR, 25% and 27%; PFS, 12% and 15%; DS, 2% and 3%; DoT, 0% and 0%; and MoA, 0% and 0%. CONCLUSION: Both patients and oncology nurses valued OS, ORR, and AEs as the most important treatment attributes for advanced melanoma, followed by PFS, whereas DS, DoT, and MoA were given less value in their treatment decisions. IMPLICATIONS FOR PRACTICE: Oncology nurses and patients have similar views on important treatment considerations for advanced melanoma, which can help build trust in shared decision-making.

Treatment preferences among Japanese women with dysmenorrhea: results from a discrete choice experiment study.

PURPOSE: To examine patient preferences for oral and intrauterine system treatments for dysmenorrhea in Japan. PATIENTS AND METHODS: A discrete choice experiment was conducted to assess the willingness to accept trade-offs among hypothetical treatment profiles. An internet-based survey was administered to women 18-49 years of age who self-reported a dysmenorrhea diagnosis or experienced dysmenorrhea at least once in the past 6 months (N=309). Choice questions included pairs of treatments presented with different attributes: mode of administration, reduction in bleeding after 6 months, chance of symptoms becoming "improved", nausea, weight gain, irregular bleeding, and risk of venous thromboembolism. Relative importance (RI) estimates were computed. RESULTS: The mean respondent age was 35.8 years (standard deviation =7.0), and 85 women (27.5%) reported that they had previously used hormonal therapy for dysmenorrhea. Treatment preference was most strongly associated with mode of administration (RI=49.8%), followed by chance of irregular bleeding (RI=17.3%). In contrast, treatment preference was most weakly associated with chance of weight gain (RI=2.4%) and reduction in bleeding after 6 months (RI=0.8%). Respondents preferred oral treatments: for twice-daily regimen, odds ratio (OR)=4.90; for once-daily fixed cyclic regimen, OR=4.20; and for once-daily flexible extended regimen, OR=2.44; whereas for intrauterine system, OR=0.02 (p<0.001 for all). Those with prior hormonal therapy experience exhibited the same pattern. CONCLUSION: Mode of administration factored heavily in dysmenorrhea treatment preferences. Women of reproductive age preferred oral medication, especially twice-daily regimen and once-daily fixed cyclic regimen. Findings can potentially help to improve physician-patient communication and treatment decision making. Physicians should consider factors that can influence patient preference to optimize treatment acceptance and adherence.

Patient and oncologist preferences for attributes of treatments in advanced melanoma: a discrete choice experiment.

PURPOSE: To examine and compare patient and oncologist preferences for advanced melanoma treatment attributes and to document their trade-offs for benefits with risks. MATERIALS AND METHODS: A discrete choice experiment (DCE) was conducted among advanced melanoma patients and oncologists. Qualitative pilot testing was used to inform the DCE design. A series of scenarios asked stakeholders to choose between two hypothetical medications, each with seven attributes: mode of administration (MoA), dosing schedule (DS), median duration of therapy (MDT), objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and grade 3-4 adverse events (AEs). Hierarchical Bayesian logistic regression models were used to determine patients' and oncologists' choice-based preferences, analysis of variance models were used to estimate the relative importance of attributes, and independent t-tests were used to compare relative importance estimates between stakeholders. RESULTS: In total, 200 patients and 226 oncologists completed the study. OS was most important to patients (33%), followed by AEs (29%) and ORR (25%). For oncologists, AEs were most important (49%), followed by OS (34%) and ORR (12%). An improvement from 55% to 75% in 1-year OS was valued similar in magnitude to a 23% decrease (from 55% to 32%) in likelihood of AEs for oncologists. CONCLUSION: Patients valued OS, AEs, and ORR sequentially as the most important attributes in making a treatment decision, whereas oncologists valued AEs most, followed by OS and ORR. In comparison, patients differed significantly from oncologists on the importance of ORR, AEs, and PFS, but were consistent in OS and the rest of attributes.

Patient preferences for treatment of castration-resistant prostate cancer in Japan: a discrete-choice experiment.

BACKGROUND: Up to a fifth of patients diagnosed with prostate cancer (PC) will develop castration-resistant prostate cancer (CRPC), which has been associated with a poor prognosis. The aim of this study was to consider the patient perspective as part of the overall treatment decision-making process for CRPC, given that an alignment between patient preference and prescribing has been shown to benefit patient outcomes. This study examines preferences of patients with CRPC in Japan for treatment features associated with treatments like RA-223, abiraterone, and docetaxel and to examine the extent to which treatment preferences may vary between symptomatic and asymptomatic patients. METHODS: A two-phase research approach was implemented. In Phase 1, N = 8 patients with CRPC were recruited from a single hospital to complete a qualitative interview to provide feedback on the draft survey. In Phase 2, N = 134 patients with CRPC were recruited from five hospitals to complete a paper survey. The survey included 6 treatment choice questions, each asking patients to choose between two hypothetical treatments for their CRPC. Each treatment alternative was defined by the following attributes: length of overall survival (OS), time to a symptomatic skeletal event (SSE), method of administration, reduction in the risk of bone pain, treatment-associated risk of fatigue and lost work days. A hierarchical Bayesian logistic regression was used to estimate relative preference weights for each attribute level and mean relative importance. RESULTS: A total of N = 133 patients with CRPC completed the survey and were included in the final analysis. Patients had a mean age of 75.4 years (SD = 7.4) and had been diagnosed with PC a mean of 6.5 years prior (SD = 4.4). Over the attribute levels shown, fatigue (relative importance [RI] = 24.9 %, 95 % CI: 24.7 %, 25.1 %) was the most important attribute, followed by reduction in the risk of bone pain (RI = 23.2 %, 95 % CI: 23.0 %, 23.5 %), and OS (RI = 19.2 %, 95 % CI: 19.0 %, 19.4 %). Although symptomatic patients placed significantly more importance on delaying an SSE (p < .05), no other preference differences were observed. CONCLUSIONS: CRPC patients were more concerned about reduced quality of life from side effects of treatment rather than extension of survival, which may have implications for shared decision-making between patients and physicians.

Patient preferences and treatment adherence among women diagnosed with metastatic breast cancer.

BACKGROUND: Given the various profiles (eg, oral vs intravenous administration, risk of hot flashes vs fatigue) of treatment options (eg, endocrine therapy, chemotherapy) for metastatic breast cancer (mBC), how patients value these attributes of their medications has implications on making treatment decisions and on adherence. OBJECTIVES: To understand how patients trade off medication side effects with improved effectiveness and/or quality of life, to provide estimates of nonadherence among women with mBC, and to quantify the association of medication nonadherence with health outcomes. METHODS: The study was a cross-sectional, Internet-based survey of 181 women diagnosed with mBC who were recruited from cancer-specific online panels (response rate, 7%). Treatment information, demographics, nonadherent behaviors, and quality of life assessed by the Functional Assessment of Cancer Therapy-Breast (FACT-B) were collected in the survey, and each respondent completed a choice-based conjoint exercise to assess patient preferences. The patients' preferences were analyzed using hierarchical Bayesian logistic regression models, and the association between the number of nonadherent behaviors and the health outcomes was analyzed using general linear models. RESULTS: The mean age of the patient sample was 52.2 years (standard deviation, ±9.1), with 93.9% of participants being non-Hispanic white. Results from the conjoint model indicated that effectiveness (overall survival) was of primary importance to patients, followed by side effects-notably alopecia, fatigue, neutropenia, motor neuropathy, and nausea/vomiting-and finally, dosing regimen. In all, 34.8% of survey respondents either discontinued their treatment or were nonadherent to their treatment regimen. Among those who have ever used oral chemotherapy (N = 95; 52.5%) and those currently using oral chemotherapy (N = 44; 24.3%), the number of nonadherent behaviors was significantly associated with a decrease in functional well-being (b [unstandardized regression coefficient] = -2.01 for patients who had ever used a targeted therapy and b = -3.14 for current users of a targeted therapy), FACT-General total score (b = -4.30 and b = -7.37, respectively), FACT-B total score (b = -3.93 and b = -6.11, respectively), and FACT trial outcome index (b = -5.22 and b = -8.63, respectively; all P <.05). CONCLUSIONS: Patients were willing to accept substantial additional risks from side effects for gains in overall survival. Approximately 33% of women with mBC reported engaging in nonadherent behaviors. Because forgetfulness and adverse events were among the most frequent reasons for nonadherence, these results suggest that less complex treatment regimens, as well as regimens with less toxic profiles, may be associated with improvements in adherence and, subsequently, could correspond to perceptible patient benefits.

Clozapine and glycinamide prevent MK-801-induced deficits in the novel object recognition (NOR) test in the domestic rabbit (Oryctolagus cuniculus).

Studies in humans indicate that acute administration of sub-anesthetic doses of ketamine, an NMDA receptor antagonist, provokes schizophrenic-like symptoms in healthy volunteers, and exacerbates existing symptoms in individuals with schizophrenia. These and other findings suggest that NMDA receptor hypofunction might participate in the pathophysiology of schizophrenia, and have prompted the development of rodent pharmacological models for this disorder based on acute or subchronic treatment with NMDA receptor antagonists, as well as the development of novel pharmacotherapies based on increasing extrasynaptic glycine concentrations. In the present study, we tested whether acute hyperlocomotory behavior and/or deficits in the novel object recognition (NOR) task, induced in male rabbits by the acute subcutaneous (s.c.) administration of MK-801 (0.025 and 0.037 mg/kg s.c., respectively), were prevented by prior administration of the atypcial antipsychotic, clozapine (0.2mg/kg, s.c.), or the glycine pro-drug glycinamide (56 mg/kg, s.c.). We found that clozapine fully prevented the MK-801-induced hyperlocomotion, and both clozapine and glycinamide prevented MK-801-induced deficits in the NOR task. The present results show that MK-801-induced hyperlocomotion and deficits in the NOR task in the domestic rabbit demonstrate predictive validity as an alternative animal model for symptoms of schizophrenia. Moreover, these results indicate that glycinamide should be investigated in pre-clinical models of neuropsychiatric disorders such as schizophrenia, obsessive compulsive disorder and anxiety disorders, where augmentation of extrasynaptic glycine concentrations may have therapeutic utility.

One-trial object recognition memory in the domestic rabbit (Oryctolagus cuniculus) is disrupted by NMDA receptor antagonists.

The spontaneous response to novelty is the basis of one-trial object recognition tests for the study of object recognition memory (ORM) in rodents. We describe an object recognition task for the rabbit, based on its natural tendency to scent-mark ("chin") novel objects. The object recognition task comprised a 15min sample phase in which the rabbit was placed into an open field arena containing two similar objects, then removed for a 5-360min delay, and then returned to the same arena that contained one object similar to the original ones ("Familiar") and one that differed from the original ones ("Novel"), for a 15min test phase. Chin-marks directed at each of the objects were registered. Some animals received injections (sc) of saline, ketamine (1mg/kg), or MK-801 (37µg/kg), 5 or 20min before the sample phase. We found that chinning decreased across the sample phase, and that this response showed stimulus specificity, a defining characteristic of habituation: in the test phase, chinning directed at the Novel, but not Familiar, object was increased. Chinning directed preferentially at the novel object, which we interpret as novelty-induced sensitization and the behavioral correlate of ORM, was promoted by tactile/visual and spatial novelty. ORM deficits were induced by pre-treatment with MK-801 and, to a lesser extent, ketamine. Novel object discrimination was not observed after delays longer than 5min. These results suggest that short-term habituation and sensitization, not long-term memory, underlie novel object discrimination in this test paradigm.