Comparative Medicine

The goal of this study was to characterize acute neuronal injury in a novel nonhuman primate (NHP) ischemic stroke model by using multiple outcome measures. Silk sutures were inserted into the M1 segment of the middle cerebral artery of rhesus macaques to achieve permanent occlusion of the vessel. The sutures were introduced via the femoral artery by using endovascular microcatheterization techniques. Within hours after middle cerebral artery occlusion (MCAO), infarction was detectable by using diffusion-weighted MRI imaging. The infarcts expanded by 24 h after MCAO and then were detectable on T2-weighted images. The infarcts seen by MRI were consistent with neuronal injury demonstrated histologically. Neurobehavioral function after MCAO was determined by using 2 neurologic testing scales. Neurologic assessments indicated that impairment after ischemia was limited to motor function in the contralateral arm; other neurologic and behavioral parameters were largely unaffected. We also ...

A segmental tibial defect model in a large animal can provide a basis for testing materials and techniques for use in nonunions and severe trauma. This study reports the rationale behind establishing such a model and its design and conclusions. After ethics approval of the study, aged ewes (older than 5 y; n = 12) were enrolled. A 5-cm mid diaphyseal osteoperiosteal defect was made in the left tibia and was stabilized by using an 8-mm stainless-steel cross-locked intramedullary nail. Sheep were euthanized at 12 wk after surgery and evaluated by using radiography, microCT, and soft-tissue histology techniques. Radiology confirmed a lack of hard tissue callus bridging across the defect. Volumetric analysis based on microCT showed bone growth across the 16.5 cm(3) defect of 1.82 ± 0.94 cm(3). Histologic sections of the bridging tissues revealed callus originating from both the periosteal and endosteal surfaces, with fibrous tissue completing the bridging in all instances. Immunohistoch...

Aim: Recent trends in comparative animal and human research inform us that collaborative research plays a key role in deciphering and solving cancer challenges. Globally, cancer is a devastating diagnosis with an increasing burden in both humans and dogs and ranks as the number three killer among humans in Kenya. This study aimed to provide comparative information on cancers affecting humans and dogs in Nairobi, Kenya. Materials and Methods: Dog data collection was by cancer case finding from five veterinary clinics and two diagnostic laboratories, whereas the human dataset was from the Nairobi Cancer Registry covering the period 2002-2012. The analysis was achieved using IBM SPSS Statistics ® v.20 (Dog data) and CanReg5 (human data). The human population was estimated from the Kenya National Census, whereas the dog population was estimated from the human using a human:dog ratio of 4.1:1. Results: A total of 15,558 human and 367 dog cancer cases were identified. In humans, females had higher cancer cases 8993 (an age-standardized rate of 179.3 per 100,000) compared to 6565 in males (122.1 per 100,000). This order was reversed in dogs where males had higher cases 198 (14.9 per 100,000) compared to 169 (17.5 per 100,000) in females. The incident cancer cases increased over the 11-year study period in both species. Common cancers affecting both humans and dogs were: Prostate (30.4, 0.8), the respiratory tract (8.3, 1.3), lymphoma (5.6, 1.4), and liver and biliary tract (6.3, 0.5), whereas, in females, they were: Breast (44.5, 3.6), lip, oral cavity, and pharynx (8.8, 0.6), liver and biliary tract (6.5, 1.2), and lymphoma (6.0, 0.6), respectively, per 100,000. Conclusion: The commonality of some of the cancers in both humans and dogs fortifies that it may be possible to use dogs as models and sentinels in studying human cancers in Kenya and Africa. We further infer that developing joint animal-human cancer registries and integrated cancer surveillance systems may lead to accelerated detection of the risks of cancer in Africa.

Measurement of the biparietal diameter (BPD) by use of B-mode ultrasound provides a useful means for assessment of gestational age and brain growth in humans during pregnancy. Recording of flow velocity waveforms from the umbilical artery, using Doppler ultrasound, is used to assess development of the fetal placental circulation. We sought to measure these ultrasound parameters during normal pregnancy in the guinea pig and develop normative data. Measurements of BPD were made on 205 fetuses of various gestational ages; 114 fetuses had 2 or more serial studies performed (total n = 474). BPD increased from 0.806cm at 22 to 26 days, to 1.922cm at term (69 days), (y = -0.00043x2 + 0.06881x - 0.75941, with an r value of 0.995, where x = days' gestation, y = biparietal diameter [cm]). Umbilical artery flow velocity waveform resistance index (RI) decreased as gestation advanced (y = -0.012x + 1.294 with an r value of 0.887, where x = days gestation, y = RI) reflecting expansion of the ...