The nervous system and the immune system communicate extensively with each other in order to maintain homeostasis and to regulate the immune response. The peripheral nervous system (PNS) communicates specifically with the immune system according to local interactions, including the “hardwiring” of sympathetic/parasympathetic (efferent) and sensory nerves (afferent) to lymphoid tissue and organs. To reveal this type of bidirectional neuroimmune interaction at the microscopic level, we used immunofluorescent staining of glial fibrillary acidic protein (GFAP) coupled with confocal microscopy/3D reconstruction to reveal the distribution of nonmyelinating Schwann cells (NMSCs) and their interactions with immune cells inside mouse spleen. Our results demonstrate i) the presence of an extensive network of NMSC processes in all splenic compartments including the splenic nodules, periarteriolar lymphoid sheath (PALS), marginal zone, trabecula, and red pulp; ii) the close association of NMSC processes with blood vessels (including central arteries and their branches, marginal sinuses, penicillar arterioles and splenic sinuses); iii) the close “synapse-like” interaction/association of NMSC processes with various subsets of dendritic cells (DCs; e.g., CD4+CD11c+ DCs, B220+CD11c+ DCs, and F4/80+ CD11c+ DCs), macrophages (F4/80+), and lymphocytes (B cells, CD4+ T helper cells). Our novel findings concerning the distribution of NMSCs and NMSC-leukocytes interactions inside mouse spleen should improve our understanding of the mechanisms through which the PNS affects cellular- and humoral-mediated immune responses in a variety of health conditions and infectious/non-infectious diseases.

Background Patella alta is the proximal displacement of the patella within the femoral trochlea. Previous studies have identified an association between patella alta and patella luxation. Distalisation of the tibial tuberosity has been recommended to establish proximodistal alignment of the stifle extensor mechanism with the underlying femur in dogs affected by patella alta. However, a recent canine ex vivo study found stifle extensor mechanism load increased significantly following tibial tuberosity distalisation. Generation of excessive load within the stifle extensor mechanism was avoidable by performing a combined transverse femoral ostectomy and tibial tuberosity distalisation. Case report Two dogs presented with acute onset left hindlimb lameness and medial patella luxation. The left patellar ligament length to patella length ratio was 2.37 and 2.39 in each dog (reference range 1.33–2.06), consistent with patella alta. No other stifle abnormalities were identified. Proximodistal stifle extensor mechanism alignment was corrected with a combined transverse femoral ostectomy and tibial tuberosity distalisation. The postoperative ratio of the distance between the proximal pole of the patella and femoral condyle to patella length ratio (A : P) fell within the corrected reference range (1.52–2.44). Follow‐up orthopaedic examination and postoperative radiographs at 10–12 weeks demonstrated clinical bone union of the femoral ostectomy and tibial tuberosity distalisation sites. No evidence of medial patella luxation or lameness could be detected. Conclusion A combined transverse femoral ostectomy and tibial tuberosity distalisation technique resolved medial patella luxation with patella alta in two dogs. Additionally, the normal A : P reference interval should be corrected to 1.52–2.44.

Medial patellar luxation in this population of English Staffordshire Bull Terriers was characterized by a decrease in femoral anteversion, external rotation of the femoral diaphysis, and decreased tibial valgus. These findings may help inform clinical decision making when performing osteotomy for treatment of medial patellar luxation in this breed.

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A study using an ovine model of transdermal intrathecal catheterization was planned to investigate the neurotoxicity of magnesium sulfate. Nonpregnant Merino cross ewes (n = 8; age, 5 y; weight, 55.0 ± 6.5 kg) were anesthetized for placement of a lumbar intrathecal catheter. The study protocol defined a 5-d recovery period after introduction of the catheter before the administration of test substances (2 mL of 0.9% saline or 50 or 150 mg MgSO4) followed by euthanasia 1 wk later. Although 3 sheep successfully completed the study as planned, one of the remaining 5 sheep was withdrawn when the catheter was accidentally dislodged 2 d after anesthesia; another was withdrawn because of persistent neurologic deficits of the left hindlimb and intense pruritus during the first 24 h after placement of the catheter; and the remaining 3 animals experienced unacceptable complications within the first 4 h of administration of the test substance. These complications included hindlimb weakness, intense irritation or pruritus of the hindlimbs, recumbency, inability to stand, spasm of the hindlimb, and arching of the back. Postmortem examination of 4 sheep with clinical signs revealed similar gross findings: acute, segmental myelomalacia and hemorrhage within the spinal cord parenchyma in the region of the catheter. Histologic changes included segmental areas of acute myelomalacia, consistent with the intraparenchymal placement of the catheter. Postmortem CT imaging of 3 sheep confirmed the location of the catheter within the spinal cord. Procedural refinement for the placement of intrathecal catheters in sheep by avoiding an invasive surgical procedure was unsuccessful. We therefore recommend a complete or partial surgical approach for the insertion of an intrathecal catheter in sheep or fluoroscopy or ultrasonography intraoperatively to confirm correct placement of the catheter.