Technical note: A comparison of DNA collection methods in cattle and yaks.

A variety of biological materials are suitable for the analysis of bovine DNA. The objective of this study was to evaluate the ease of collection, storage, and cost as well as quality and quantity of DNA samples obtained from Bos taurus (European cattle) and Bos grunniens (yak) using 2 different sample types: whole blood sampling and nasal swabs. Hair follicle DNA samples from yaks were also analyzed. Deoxyribonucleic acid samples were collected from 1 herd of Black Angus yearling bulls (n = 166) and 1 herd of yaks (n = 24). A NanoDrop Bioanalyzer ND1000 was used to quantify DNA. To assess DNA purity, absorbance ratios were determined at wavelengths of 260 nm relative to 280 nm and 260 nm relative to 230 nm. Single nucleotide polymorphism genotyping was performed using a competitive allele-specific PCR (KASP) genotyping system and the call rates to 3 specific SNP were compared. Using a commercially available nonautomated ethanol DNA extraction technique, nasal swabs yielded a greater quantity of DNA than blood (P < 0.0001) and a greater quality DNA sample than blood (P < 0.0001). Blood and nasal swab performance in SNP genotyping assays were similar (P = 0.5). The greater expense of nasal swabs was offset by their ease of use: less time, skill, and equipment was needed to obtain a sample and the storage of samples was more convenient (room temperature). In yaks, accessing the coccygeal vein, which is relatively straightforward in cattle, was difficult. Nasal swabbing and hair follicle sampling in yaks was performed relatively easily. Yak hair follicles were a poor source of DNA. In conclusion, DNA collection using nasal swabs was more convenient and provided a greater quantity of DNA and better quality sample than blood collection in both Angus and yak. Notably, yak hair was a poor source of DNA, and yak blood was difficult to obtain.

The neuroanatomy of pain.

Pain is the most frequent complaint of patients visiting all types of physicians. With pain perception, sensation is described and perceived as causing actual tissue damage. In contrast, nocioception is defined as a response specific to a potentially tissue-damaging stimuli. This articles defines the various nocioceptive pathways and connections.

Avascular necrosis of the first metatarsal head following Austin osteotomy: a follow-up study.

A prospective study is described of 12 consecutive patients with hallux abducto valgus deformity in whom an Austin osteotomy without lateral release was performed. All patients had similar postoperative care and magnetic resonance images (MRI) studies of their first metatarsals. The MRI was performed in T1- and T2-weighted images with algorithms programmed to image changes in the bone consistent with avascular necrosis of the first metatarsal head. One of the 12 patients following Austin osteotomy without lateral release had changes on MRI consistent with avascular necrosis of the first metatarsal head. These results were then compared with the prior study of 20 patients that had the Austin osteotomy with lateral release using the Fisher's exact test for small populations, and a value of 0.023 was found (0.05 > 95% confidence level). The Austin osteotomy with lateral release significantly increases the risk of developing avascular necrosis of the first metatarsal head and should only be performed in instances where the soft tissue contracture is largely contributing to the hallux abducto valgus deformity.

Objective identification of ankle equinus deformity and resulting contracture.

A quantitative diagnostic technique is described for identifying contracture at the ankle joint in patients with equinus deformity, hence addressing the shortcoming of the conventional clinical diagnostic procedure. To gain a better understanding of how contracture contributes to equinus deformity, a study was designed that compared the torque about the ankle joint before and after administering a tibial nerve block to equinus patients and to a control group. Functional equinus, manifested by walking and early heel rise, is defined as inadequate dorsiflexion for normal gait. The ability to accurately identify an equinus condition, and contracture as the contributing factor in equinus deformity, has important implications for the type of treatment prescribed and the evaluation of treatment effectiveness.