Effects of isolation housing stress and mouse strain on intravenous cocaine self-administration, sensory stimulus self-administration, and reward preference.

Sensory stimuli are natural rewards in mice and humans. Consequently, preference for a drug reward relative to a sensory reward may be an endophenotype of addiction vulnerability. In this study, we developed a novel behavioral assay to quantify the preference for intravenous drug self-administration relative to sensory stimulus self-administration. We used founder strains of the BXD recombinant inbred mouse panel (C57BL/6J, DBA/2J) and a model of stress (isolation vs enriched housing) to assess genetic and epigenetic effects. Following 10 weeks of differential housing, all mice were tested under three reward conditions: sensory rewards available, cocaine rewards available, both rewards available. When a single reward was available (sensory stimuli or cocaine; delivered using distinct levers), DBA/2J mice self-administered significantly more rewards than C57BL/6J mice. When both rewards were available, DBA/2J mice exhibited a significant preference for cocaine relative to sensory stimuli; in contrast, C57BL/6J mice exhibited no preference. Housing condition influenced sensory stimulus self-administration and strain-dependently influenced inactive lever pressing when both rewards were available. Collectively, these data reveal strain effects, housing effects, or both on reward self-administration and preference. Most importantly, this study reveals that genetic mechanisms underlying preference for a drug reward relative to a nondrug reward can be dissected using the full BXD panel.

Intravenous fentanyl self-administration in male and female C57BL/6J and DBA/2J mice.

The genetic mechanisms underlying fentanyl addiction, a highly heritable disease, are unknown. Identifying these mechanisms will lead to better risk assessment, early diagnosis, and improved intervention. To this end, we used intravenous fentanyl self-administration to quantify classical self-administration phenotypes and addiction-like fentanyl seeking in male and female mice from the two founder strains of the BXD recombinant inbred mouse panel (C57BL/6J and DBA/2J). We reached three primary conclusions from these experiments. First, mice from all groups rapidly acquired intravenous fentanyl self-administration and exhibited a dose-response curve, extinction burst, and extinction of the learned self-administration response. Second, fentanyl intake (during acquisition and dose response) and fentanyl seeking (during extinction) were equivalent among groups. Third, strain effects, sex effects, or both were identified for several addiction-like behaviors (cue-induced reinstatement, stress-induced reinstatement, escalation of intravenous fentanyl self-administration). Collectively, these data indicate that C57BL/6J and DBA/2J mice of both sexes were able to acquire, regulate, and extinguish intravenous fentanyl self-administration. Moreover, these data reveal novel strain and sex effects on addiction-like behaviors in the context of intravenous fentanyl self-administration in mice and indicate that the full BXD panel can be used to identify and dissect the genetic mechanisms underlying these effects.

Prevalence and Levels of Parasitemia of Hepatozoon sp. (Apicomplexa: Adeleorina) in Four Gopher Tortoise (Gopherus polyphemus) Populations of South FLORIDA, USA.

Hepatozoon prevalence (occurrence) and parasitemia (intensity) levels were documented in 67 individuals of the threatened gopher tortoise (Gopherus polyphemus) for the first time in four South Florida, US, locations: Jonathan Dickinson State Park (JDSP), Pine Jog Preserve (PJP), Florida Atlantic University Preserve (FAUP), and Blazing Star Preserve (BSP). Sex ratios (males:females) per site were 0.44 at JDSP, 0.72 at PJP, 1.42 at FAUP, and 0.40 at BSP, but no significant differences in the carapace length were found between the two sexes (independent t-test; P=0.101). Hepatozoon sp. was found in 13% (9/67) of tortoises. Percentages of infected tortoises were 22% (5/23) males and 6% (2/33) females. Prevalence and parasitemia were low or nonexistent within sampled tortoises at each of the study sites, although the highest prevalence and parasitemia values were found in gopher tortoises at JDSP (23%, 4/17) which also harbored the highest infection levels, reaching 349/10,000 erythrocytes. No infection was detected within sampled gopher tortoises at PJP.

Comparative Stability of Vitamin K1 Oral Liquids Prepared in Sterile Water for Injection and Stored in Amber Glass Bottles and Amber Plastic Syringes.

The purpose of this study was to evaluate the stability of vitamin K1 oral liquids in Sterile Water for Injection when stored in amber glass bottles and amber plastic syringes under refrigerated conditions. Four 100-mL batches of vitamin K1 in Sterile Water for Injection were prepared in amber glass bottles to protect from light. One of the batches was divided into 1-mL aliquots, using amber plastic oral syringes, and capped. The prepared bottles and syringes were stored in a laboratory refrigerator. On each day of sampling, 1-mL aliquots were removed from each bottle and mixed with an equal volume of ethanol. Likewise, the contents of sample syringes were mixed with ethanol to achieve an assay concentration of 0.5 mg/mL. Recovery of vitamin K1 in the compounded samples was quantified against a United States Pharmacopeia reference standard. Quantification was achieved using a stability-indicating high-performance liquid chromatography with ultraviolent light detection method. Product stability is defined as 90% to 110% of the initial concentration. The percent recovery in the Sterile Water for Injection preparations in glass bottles remained above 90% for the 105-day duration of the study, but some samples stored in amber plastic syringes fell below 90% on day 21. Furthermore, a statistically significant difference (2-way ANOVA, P < 0.0001) emerged between syringes at day 0 and day 30, and this trend continued through the day 60, 90, and 105 samples. The only statistically significant difference found within the bottle-stored samples occurred on day 105 (versus zero, P = 0.0465), but the recovery on day 105 still exceeded 90%. Vitamin K1 in Sterile Water for Injection, stored in a refrigerated amber glass bottle, is stable for 105 days. This preparation can also be stored in amber plastic syringes, but this decreases the beyond-use date to 14 days.

A Survey of Gopherus polyphemus Intestinal Parasites in South Florida.

Gopherus polyphemus populations are diminishing throughout their range due to urbanization, fragmentation, and poor habitat management. Increased population densities, poor habitat quality, and lack of fire may influence disease transmission. Parasite roles within wild tortoise populations are largely unknown; despite evidence these pathogens may pose significant health risks. This study provides a baseline of gopher tortoise intestinal parasites across South Florida and reports on how varying environmental and tortoise characteristics may affect intestinal parasite species prevalence and approximate loads. Tortoise fecal samples were taken from six tortoise populations across five South Florida sites. Seven species of intestinal parasites were discovered from 123 tortoises. Identified parasites include endohelminths such as cyathostomes, pinworms, ascarids, flukes, and protozoans including Eimeria, Cryptosporidium, and Amoeba species. Significant differences in parasite prevalence and loads were seen between sites, while parasitism among sex, size class, and habitat type remained relatively ubiquitous.

Stability of a pyrimethamine suspension compounded from bulk powder.

PURPOSE: Development of a stability-indicating high-performance liquid chromatography (HPLC) method for pyrimethamine analysis, with subsequent application of that method to assess the 90-day stability of a pyrimethamine suspension compounded from bulk USP-grade pyrimethamine powder, is described. METHODS: A stability-indicating method of HPLC with ultraviolet detection specific to pyrimethamine was developed according to pharmacopeial recommendations and validated. The method was applied to investigate the stability of a 2-mg/mL pyrimethamine suspension in a vehicle consisting of Ora-Plus and Ora-Sweet (Perrigo) over a period of 90 days. Three replicate test preparations were stored at room temperature or refrigerated at 4.3-5.2 °C, and samples were analyzed in duplicate immediately after preparation and on study days 1, 2, 4, 7, 10, 14, 21, 30, 48, 60, 75, and 90. RESULTS: The 2-mg/mL suspension of pyrimethamine in Ora-Plus and Ora-Sweet retained 90-110% of the labeled potency to 90 days at both temperature ranges. However, color changes in the samples stored at room temperature observed at day 60 indicated that a beyond-use date less than 90 days from the preparation date should be specified when the suspension is to be stored at room temperature. CONCLUSION: The study demonstrated that USP-grade pyrimethamine powder can be formulated as a 2-mg/mL suspension in a vehicle of Ora-Plus and Ora-Sweet and is stable when stored at room temperature and when refrigerated, in amber plastic bottles, for 48 and 90 days, respectively.

Beyond-use dating of lidocaine alone and in two "magic mouthwash" preparations.

PURPOSE: Beyond-use dating (BUD) of lidocaine alone and in two "magic mouthwash" preparations stored in amber oral syringes at room temperature was determined. METHODS: Two formulations of mouthwash containing oral topical lidocaine 2% (viscous), diphenhydramine 2.5 mg/mL, and aluminum hydroxide-magnesium hydroxide-simethicone were prepared in 1:1:1 and 1:2.5:2.5 ratios, divided into 3-mL samples, and stored in unit-dose oral amber syringes. Unit-dose single-product lidocaine samples were also prepared to serve as controls and stored in oral amber syringes. The lidocaine concentrations in these samples were measured periodically for 90 days. A stability-indicating high-performance liquid chromatographic method was developed and validated for system suitability, accuracy, repeatability, intermediate precision, specificity, linearity, and robustness. RESULTS: Based on the calculated percentages versus the initial concentration and the results from an analysis of variance comparing the two formulations, a BUD of 21 days is deemed appropriate for both magic mouthwash formulations. Based on the stability data, published safety concerns, and lack of efficacy in combination, packaging and dispensing lidocaine separately from other ingredients are recommended when administering magic mouthwash mixtures. Utilizing a 90-day BUD, lidocaine can be packaged separately from other magic mouthwash ingredients in individual dosage units and applied to the oral cavity using the swish-and-spit method. The delivery of the diphenhydramine and aluminum hydroxide-magnesium hydroxide-simethicone could be separated, allowing for a swish-and-swallow method of administration. CONCLUSION: A BUD of 21 days is recommended for lidocaine prepared with diphenhydramine and aluminum hydroxide-magnesium hydroxide-simethicone in ratios of 1:1:1 and 1:2.5:2.5 and stored at room temperature in amber oral plastic syringes.

Neural correlates of semantic activation spreading on the path to picture naming in adults who stutter.

OBJECTIVE: On the path to picture naming, words that relate semantically to the pictured object become activated in the mental lexicon. We used a neuroscientific approach to investigate this semantic activation spreading process in adults who stutter (AWS). METHODS: Fourteen AWS and 14 adults who do not stutter (AWNS) completed a picture-word priming task. On each trial, a picture was named at a delay. On some trials, an unattended auditory probe word was presented after the picture, before naming commenced. Event-related potentials recorded to probe words Semantically-Related to the picture labels, and to probe words Semantically- and Phonologically-Unrelated to the picture labels, were compared using spatial-temporal principal component analysis. RESULTS: Posterior N400 amplitude was attenuated for Semantically-Related versus Unrelated probes in AWNS, while in AWS posterior N400 amplitude was enhanced for Semantically-Related versus Unrelated probes. Marginal albeit potentially relevant group differences in the morphology of other ERP components were also observed. CONCLUSIONS: The posterior N400 results point to a strategic, inhibitory influence on semantic activation spreading in AWS on the path to naming. Group differences in the amplitude of other ERP components tentatively suggest that AWS allocated attentional resources differently than the AWNS during the task. Preliminary ERP evidence of intact conceptual (as opposed to lexical-semantic) priming in the AWS is also discussed. SIGNIFICANCE: This study contributes to a growing body of research describing linguistic performance in AWS.