Photoacoustic tomography imaging and estimation of oxygen saturation of hemoglobin in ocular tissue of rabbits.

This study evaluated in vivo imaging capabilities and safety of qualitative monitoring of oxygen saturation of hemoglobin (sO2) of rabbit ciliary body tissues obtained with acoustic resolution (AR) photoacoustic tomography (PAT). AR PAT was used to collect trans-scleral images from ciliary body vasculature of seven New Zealand White rabbits. The PAT sO2 measurements were obtained under the following conditions: when systemic sO2 as measured by pulse oximetry was between 100% and 99% (level 1); systemic sO2 as measured by pulse oximetry was between 98% and 90% (level 2); and systemic sO2 as measured by pulse oximetry was less than 90% (level 3). Following imaging, histological analysis of ocular tissue was conducted to evaluate for possible structural damage caused by the AR PAT imaging. AR PAT was able to resolve anatomical structures of the anterior segment of the eye, viewed through the cornea or anterior sclera. Histological studies revealed no ocular damage. On average, sO2 values (%) obtained with AR PAT were lower than sO2 values obtained with pulse oximetry (all p < 0.001): 86.28 ± 4.16 versus 99.25 ± 0.28, 84.09 ± 1.81 vs. 95.3 ± 2.6, and 64.49 ± 7.27 vs. 71.15 ± 10.21 for levels 1, 2 and 3 respectively. AR PAT imaging modality is capable of qualitative monitoring for deep tissue sO2 in rabbits. Further studies are needed to validate and modify the AR PAT modality specifically for use in human eyes. Having a safe, non-invasive method of in vivo imaging of sO2 in the anterior segment is important to studies evaluating the role of oxidative damage, hypoxia and ischemia in pathogenesis of ocular diseases.

Increased incidence of vaginal septum in C57BL/6J mice since 1976.

Decreased fertility was observed in a breeding colony of C57BL/6J mice. On examination, a dorsoventral vaginal septum was detected in many females. This defect was identified in 1976, with incidence of 4.0% in this strain. Our objective was to determine whether incidence of this condition has increased and whether this defect was associated with the observed infertility. We report incidence of 11.3%, nearly triple the original reported incidence. For comparison, incidence of vaginal septum in C57BL/6N females was determined and was found to be 1%. We performed a breeding study using normal and affected C57BL/6J females to evaluate fertility in affected females. Our data were consistent with those of the 1976 report; fertility was decreased in females with an intact vaginal septum. In 50% of affected females, the septum remained intact after breeding. The fertility for this subgroup of vaginal septum-retained females was 14.3%, compared with 85.7% in females whose septum ruptured and 75.0% in normal females (statistically significant, P = 0.02). On the basis of our results, we provide animal and financial loss data due to the defect. Lastly, we provide suggestions on how to minimize animal losses and be in accordance with the principles of the 3Rs (replacement, refinement, reduction).

What is your diagnosis?: Multifocal subcutaneous tumors in a young male baboon.

A juvenile male baboon (Papio cynocephalus anubis), while being held in quarantine prior to research assignment at the Washington National Primate Research Center (WaNPRC), presented with three soft tissue masses on the right elbow, wrist, and knee on routine physical examination. The masses were subcutaneous and did not appear to cause any discomfort to the animal. An excisional biopsy of the knee mass was submitted for histopathologic analysis and found to be poorly defined, rapidly growing, and of undetermined histogenesis. Euthanasia was elected, and a full necropsy done with samples collected for histopathologic analysis. By immunohistochemistry, the "large" cells in the masses were suggestive of a mesenchymal, nonmacrophage origin because of their being positive for vimentin and negative for cytokeratin and the macrophage maturation marker CD68. Eosinophilic intracytoplasmic inclusions were seen on HE-stained sections and corresponded to aggregates of ovoid to brick-shaped viral particles on transmission electron microscopy (TEM), which proved to be the key diagnostic tool for this case. The masses were determined to be Yaba monkey tumor virus (YMTV)-induced "benign histiocytomas" by TEM.

Preparing for a semiannual IACUC inspection of a satellite zebrafish (Danio rerio) facility.

Institutions worldwide have experienced a rapid growth in the use of zebrafish as a research model for a variety of molecular and genetic studies of vertebrate development. This expansion in zebrafish research essentially has outpaced the establishment of specific recommendations for the care and use of fish in research. In some cases, this situation has created a dilemma where an Institutional Animal Care and Use Committee, which is responsible for oversight of vertebrate animal research, is not fully prepared to undertake this role for a decentralized zebrafish facility. IACUC inspectors will be more equipped to ask pertinent questions by understanding the basic principles of zebrafish health and facility management. Concurrently, zebrafish facility managers can contribute to the progress of a semiannual facility inspection by maintaining fully accessible operating records. In the context of presenting a well-established and useful model of zebrafish management and recordkeeping to the zebrafish facility operator, the information we present here also prepares a potential IACUC inspector to conduct a constructive and positive inspection.