Locomotor activity assay in zebrafish larvae: Influence of age, strain and ethanol

Several characteristics warrant the zebrafish a refining animal model for toxicity testing in rodents, thereby contributing to the 3R principles (Replacement, Reduction, and Refinement) in animal testing, e.g. its small size, ease of obtaining a high number of progeny, external fertilization, transparency and rapid development of the embryo, and a basic understanding of its gene function and physiology. In this context we explored the motor activity pattern of zebrafish larvae, using a 96-well microtiter plate and a video-tracking system. Effects of induced light and darkness on locomotion of zebrafish larvae of different wild-type strains and ages (AB and TL, 5, 6 and 7 dpf; n=25/group) were studied. Locomotion was also measured in zebrafish larvae after exposure to different concentrations of ethanol (0; 0.5; 1; 2 and 4%) (AB and TL strain, 6 dpf; n=19/group). Zebrafish larvae showed a relatively high swimming activity in darkness when compared to the activity in light. Small differences were found between wild-type strains and/or age. Ethanol exposure resulted in hyperactivity (0.5-2%) and in hypo-activity (4%). In addition, the limitations and/or relevance of the parameters distance moved, duration of movements and velocity are exemplified and discussed. Together, the results support the suggestion that zebrafish may act as an animal refining alternative for toxicity testing in rodents provided internal and external environmental stimuli are controlled. As such, light, age and strain differences must be taken into account.     

Canadians�� willingness to receive care from physician assistants

Objective

To determine the willingness of Canadians to accept treatment from physician assistants (PAs).

Design

Respondents were asked to be surrogate patients or parents under 1 of 3 conditions selected at random. Two scenarios involved injury to themselves, with the third involving injury to their children. The wait time for a physician was assumed to be 4 hours, whereas to explore the sensitivity of patients’ preferences for a range of times, PA wait times were 30 minutes, 1 hour, and 2 hours.

Setting

Vancouver, BC.

Participants

Two hundred twenty-nine mothers attending a hospital with their children.

Main outcome measures

The main outcome measure was the proportion of individuals in each scenario who were willing to be treated by PAs for at least one of the time trade-off options offered. A secondary outcome was the proportion of individuals who changed their answers when the waiting time to see the PA varied.

Results

Regardless of the scenarios, 99% of participants opted for PAs under the personal circumstances; 96% opted for PAs when the issue involved their children. The choice favouring the PA persisted, albeit at slightly lower proportions, as the difference in wait time between PAs and physicians decreased (85% and 67% for a difference in PA and physician wait time of 3 and 2 hours, respectively).

Conclusion

These findings suggest that British Columbians are willing to be treated by PAs under most circumstances, whether this includes themselves or their children. The high level of willingness to be treated by PAs demonstrates public confidence in PA care, and suggests that the use of PAs in Canadian emergency departments or clinics is a viable policy response to decreasing primary care capacity.     

Urinary Fistulas

The four major types of urinary fistulas are renal, ureteral, vesical and urethral. Urinary fistulas may be congenital or acquired. Symptoms depend on the type and site of the fistula. Diagnosis includes recognition of the fistula and determination of its cause. Treatment may require cooperation of the urologist, general surgeon and internist.     

Association of Depressive Symptoms with Hippocampal Volume in 1936 Adults

Hippocampal atrophy is reported in major depressive disorder (MDD). However, sample sizes were generally modest, and participant characteristics, including age, differed between studies. This study used a community sample to examine relationships between current depressive symptom severity and hippocampal volume across the adult lifespan. A total of 1936 adults with magnetic resonance images of the brain and Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR) scores were included. Brain volumes were quantified using the FSL program. Multiple linear regressions were performed using left, right, and total hippocampal volume as criterion variables, and predictor variables of QIDS-SR total, total brain volume, age, gender, education, psychotropic medications, alcohol use, and race/ethnicity. Post hoc analyses were conducted in participants with QIDS-SR scores ⩾11 (moderate or greater depressive symptom severity) and <11, and older and younger adults. In the primary analysis (sample as a whole) QIDS-SR was inversely associated with total hippocampal volume (b=−0.044, p=0.032, (CI−0.019 to −0.001)) but not with left or right hippocampal volume evaluated individually. In participants with QIDS-SR scores of <11, hippocampal volumes were not associated with QIDS-SR scores. In those with QIDS-SR scores ⩾11 total, right, and left hippocampal volumes were modestly, but significantly, associated with QIDS-SR scores. The association between QIDS-SR scores and the hippocampal volume was much stronger in older persons. Findings suggest smaller hippocampal volumes among those with greater reported depressive symptom severity—an association that is strongest in people with at least moderate depressive symptom levels.     

Acquisition of Iron by Gardnerella vaginalis

Six Gardnerella vaginalis strains were examined for the ability to utilize various iron-containing compounds as iron sources. In a plate bioassay, all six strains acquired iron from ferrous chloride, ferric chloride, ferrous sulfate, ferric ammonium citrate, ferrous ammonium sulfate, bovine and equine hemin, bovine catalase, and equine, bovine, rabbit, and human hemoglobin. All six strains also acquired iron from human lactoferrin, but not from human transferrin, as determined by a liquid broth growth assay. Siderophore production was detected in eight G. vaginalis strains by the chrome azurol S universal chemical assay. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the cytoplasmic membrane proteins isolated from G. vaginalis 594 grown under iron-replete and iron-restricted conditions revealed several iron-regulated proteins ranging in molecular mass from 33 to 94 kDa. These results indicate that G. vaginalis may acquire iron from iron salts and host iron compounds.