Venipuncture Site Influences Blood-drop Volume in C57BL/6 Mice.

Many experiments require the collection of serial blood samples from mice. However, the size of mice limits the volume of blood that can be safely collected as a survival procedure. In IACUC protocols, investigators may report the amount of blood they collect from mice as a number of drops. Many institutions, including ours, use an anecdotal conversion factor (1drop of mouse blood = 25µL) to ensure that blood-collection volumes are compliant with institutional guidelines. To our knowledge, previous work has not experimentally determined the volume of a drop of mouse blood. In this 10-wk crossover experiment, 2 phlebotomists bled 30 C57BL/6J mice from 3 sites (facial, saphenous, and tail) using one or 2 different needle gauge sizes per site. Male and female mice were weighed weekly and divided among 5 groups (n = 6): left and right tail vein, left and right saphenous vein, and facial vein. A single blood drop from each site was weighed, and the volume of each drop was calculated using the average blood density determined from 8 mice terminally bled at the end of the study. Venipuncture site and side significantly influenced blood-drop weight and thus calculated volume. Facial vein puncture produced the largest drop volume (mean: 21.7µL), followed by the saphenous vein (mean: 9.97µL) and tail vein (mean: 4.96µL). Collection from the facial vein was associated with more hemorrhage and morbidity. Left-sided venipuncture was associated with slightly larger-volume blood drops, though the effect size of side was small. The results of this study may be useful in more accurately estimating blood loss via conversion of drops to volume. Our data indicate that blood collection from saphenous and tail veins minimizes blood loss relative to facial vein puncture and may optimize both serial collection of small-volume blood samples and animal welfare.

A backward cycling programme for people with Parkinson's disease: a feasibility and preliminary results study.

OBJECTIVE: To assess the feasibility of backward cycling for people with Parkinson's disease. Secondary objectives were to assess changes in gait and balance following a 6-week program. DESIGN: A single-group prospective pre-test, post-test study with 1-month follow-up. SUBJECTS/PATIENTS: Twenty-six people with Parkinson's disease (mean age: 69 (7.74) years, gender: 83% males, time since diagnosis: 6 (4.44) years). METHODS: Participants pedaled backward on a stationary bicycle for 30 minutes at moderate intensity twice a week for 6 weeks. Feasibility was assessed by acceptability, suitability, and burden. Data collected at pre- and post-intervention with 1-month follow-up included backward stepping response variables, forward/backward gait variables, Mini-Balance Evaluation Systems Test (MBT), and 6 Minute Walk Test. RESULTS: There was a high retention rate (95.8%) and adherence rate (100%) with one adverse event and minimal burden. Significant improvements were seen in step count and excursion distance during backward stepping responses, forward and backward gait velocity, forward step length, and the Mini-BESTest. CONCLUSION: Backward cycling was a feasible intervention for people with Parkinson's disease, demonstrating low burden with high retention and adherence rates, and it is a safe exercise with the potential for benefits in gait and balance variables.