Clinical and pathological findings in five dogs with nodular histiocytic iritis in the United Kingdom: A case series.

PURPOSE: The aim of this study was to describe the clinical presentation, histopathology, management, and outcome of nodular histiocytic iritis, an intraocular variant of nodular granulomatous episcleritis (NGE). METHODS: A retrospective review of the medical records of five dogs with intraocular NGE-type inflammation as diagnosed by histopathology. RESULTS: Four Border Collies and one crossbreed dog, aged 1.5-3.4 years (mean age 2.38 years). The clinical presentation was an extensive, raised, pale iris lesion of variable location. All cases were unilateral. The physical examination was normal. Complete blood count/serum biochemistry (n = 1) and thoracic radiography (n = 1) were normal. Ocular ultrasound (n = 2) was normal apart from increased iris thickness. Enucleation (n = 4) or excisional biopsy (iridectomy, n = 1) was performed because of suspected neoplasia. Following enucleation, the remaining, contralateral eye did not develop additional lesions (9 days-3.7 years follow-up). There was no recurrence following sector iridectomy with 5 months topical 1% prednisolone acetate (3.9 years follow-up). The histopathologic findings in all five cases indicated a focal histiocytic and lymphoplasmacytic anterior uveitis (iritis), similar to that seen in cases of NGE. CONCLUSION: Nodular histiocytic iritis presents as unilateral iris thickening in isolation and young Collies appear to be predisposed. The histopathological findings are similar to NGE. Although the clinical presentation resembles intraocular neoplasia, an inflammatory process should be considered, which may be amenable to medical management. Definitive diagnosis may be obtained by iris sampling.

Forming the Hematology-Oncology Collaborative Videoconferencing (CO-VID) Learning Initiative: Experiential Lessons Learned From a Novel Trainee-Led Multidisciplinary Virtual Learning Platform.

PURPOSE: COVID-19 challenged medical practice and graduate medical education. Building on previous initiatives, we describe and reflect on the formative process and goals of the Hematology-Oncology Collaborative Videoconferencing Learning Initiative, a trainee-led multi-institutional virtual COVID-19 learning model. METHODS: Clinical fellows and faculty from 13 US training institutions developed consensus needs, goals, and objectives, recruited presenters, and generated a multidisciplinary COVID-19 curriculum. Weekly Zoom conferences consisted of two trainee-led instructional segments and a trainee-moderated faculty Q&A panel. Hematology-oncology training program faculty and trainees were the targeted audience. Leadership evaluations consisted of anonymized baseline and concluding mixed methods surveys. Presenter evaluations consisted of session debriefs and two structured focus groups. Conference evaluations consisted of attendance, demographics, and pre- or postmultiple-choice questions on topic learning objectives. RESULTS: In 6 weeks, the initiative produced five conferences: antivirals, anticoagulation, pulmonology, provider resilience, and resource scarcity ethics. The average attendance was 100 (range 57-185). Among attendees providing both pre- and postconference data, group-level knowledge appeared to increase: antiviral (n = 46) pre-/postcorrect 82.6%/97.8% and incorrect 10.9%/2.2%, anticoagulation (n = 60) pre-/postcorrect 75%/93.3% and incorrect 15%/6.7%, and pulmonary (n = 21) pre-/postcorrect 66.7%/95.2% and incorrect 33.3%/4.8%. Although pulmonary management comfort appeared to increase, comfort managing of antivirals and anticoagulation was unchanged. At the conclusion of the pilot, leadership trainees reported improved self-confidence organizing multi-institutional collaborations, median (interquartile range) 58.5 (50-64) compared with baseline 34 (26-39), but did not report improved confidence in other educational or leadership skills. CONCLUSION: During crisis, trainees built a multi-institutional virtual education platform for the purposes of sharing pandemic experiences and knowledge. Accomplishment of initiative goals was mixed. Lessons learned from the process and goals may improve future disaster educational initiatives.

Characterization of electroconvulsive seizure-induced TIMP-1 and MMP-9 in hippocampal vasculature.

Degradation of the vascular basement membrane stimulates angiogenesis and is tightly controlled by balancing the actions of metalloproteases and their inhibitors. Previous work demonstrated that electroconvulsive seizure (ECS) elevates angiogenic factors and endothelial proliferation in the hippocampus. The robust induction of tissue inhibitor of matrix metalloprotease 1 (TIMP-1) in the stratum lacunosum moleculare (SLM) corresponds to sites of increased vascular density. This led us to examine the spatial and cellular expression of TIMP-1 and its substrate, matrix metalloprotease 9 (MMP-9). Chronic ECS increased TIMP-1 by 12-fold and MMP-9 by 3-fold in discrete SLM cells. We then characterized the expression of TIMP-1 mRNA in relation to vasculature in the SLM and glial-limiting membrane (GLM). Employing laser microdissection we identified the cell types associated with SLM vasculature and also phenotyped the cells expressing TIMP-1 and MMP-9. We concluded that TIMP-1 is produced by perivascular cells positive for alpha smooth actin and that MMP-9 is expressed by GFAP-positive astrocytes. These studies suggest that ECS-induced remodelling occurs at the vascular basement membrane and facilitates neovascularization.

Overexpression of uncoupling protein 3 in skeletal muscle protects against fat-induced insulin resistance.

Insulin resistance is a major factor in the pathogenesis of type 2 diabetes and is strongly associated with obesity. Increased concentrations of intracellular fatty acid metabolites have been postulated to interfere with insulin signaling by activation of a serine kinase cascade involving PKCtheta in skeletal muscle. Uncoupling protein 3 (UCP3) has been postulated to dissipate the mitochondrial proton gradient and cause metabolic inefficiency. We therefore hypothesized that overexpression of UCP3 in skeletal muscle might protect against fat-induced insulin resistance in muscle by conversion of intramyocellular fat into thermal energy. Wild-type mice fed a high-fat diet were markedly insulin resistant, a result of defects in insulin-stimulated glucose uptake in skeletal muscle and hepatic insulin resistance. Insulin resistance in these tissues was associated with reduced insulin-stimulated insulin receptor substrate 1- (IRS-1-) and IRS-2-associated PI3K activity in muscle and liver, respectively. In contrast, UCP3-overexpressing mice were completely protected against fat-induced defects in insulin signaling and action in these tissues. Furthermore, these changes were associated with a lower membrane-to-cytosolic ratio of diacylglycerol and reduced PKCtheta activity in whole-body fat-matched UCP3 transgenic mice. These results suggest that increasing mitochondrial uncoupling in skeletal muscle may be an excellent therapeutic target for type 2 diabetes mellitus.

Gene profile of electroconvulsive seizures: induction of neurotrophic and angiogenic factors.

Electroconvulsive seizure therapy (ECS) is a clinically proven treatment for depression and is often effective even in patients resistant to chemical antidepressants. However, the molecular mechanisms underlying the therapeutic efficacy of ECS are not fully understood. One theory that has gained attention is that ECS and other antidepressants increase the expression of select neurotrophic factors that could reverse or block the atrophy and cell loss resulting from stress and depression. To further address this topic, we examined the expression of other neurotrophic-growth factors and related signaling pathways in the hippocampus in response to ECS using a custom growth factor microarray chip. We report the regulation of several genes that are involved in growth factor and angiogenic-endothelial signaling, including neuritin, stem cell factor, vascular endothelial growth factor (VEGF), VGF (nonacronymic), cyclooxygenase-2, and tissue inhibitor of matrix metalloproteinase-1. Some of these, as well as other growth factors identified, including VEGF, basic fibroblast growth factor, and brain-derived neurotrophic factor, have roles in mediating neurogenesis and cell proliferation in the adult brain. We also examined gene expression in the choroid plexus and found several growth factors that are enriched in this vascular tissue as well as regulated by ECS. These data suggest that an amplification of growth factor signaling combined with angiogenic mechanisms could have an important role in the molecular action of ECS. This study demonstrates the applicability of custom-focused microarray technology in addressing hypothesis-driven questions regarding the action of antidepressants.

Regulation of growth factor receptor bound 2 by electroconvulsive seizure.

Electroconvulsive seizure (ECS) is a well-established non-chemical antidepressant that is effective in the treatment of severe depression and also in subjects resistant to chemical antidepressant treatment. Although the molecular mechanism governing the antidepressant efficacy of ECS is unknown, recent work suggests that an amplification of growth/neurotrophic signaling might play a role in mediating the therapeutic effects. In this context, we examined the regulation of growth factor receptor bound 2 (Grb2), an important adaptor molecule in several growth factor signaling cascades. In situ hybridization analysis revealed a more than 2-fold induction of Grb2 mRNA in the hippocampal dentate gyrus as well as superficial and deep layers of the cortex with both acute and chronic ECS. Grb2 also exhibited a time-dependent induction 4 and 8 h after acute ECS, returning to basal levels at 24 h. These results provide further evidence of increased growth factor signaling in response to ECS.

Electroconvulsive seizure increases adult hippocampal angiogenesis in rats.

Electroconvulsive seizure has a proven therapeutic application in the treatment of severe depression and treatment-resistant depression. Despite the efficacy of electroconvulsive seizure as a non-chemical antidepressant treatment, the mechanism of action is unclear. Elevation in hippocampal trophic factor expression and concomitant cellular proliferation are thought to play a role in its action. We examined whether the reported induction of angiogenic factors and endothelial cell proliferation leads to an increase in vascular density. Two hippocampal regions, the dentate gyrus and the stratum lacunosum moleculare (SLM), were examined employing a combination of vascular density quantification, angiogenic gene expression analysis and immunohistochemistry. A 6% increase in vascular density was observed in the dentate gyrus but this did not achieve statistical significance. The SLM of the hippocampus exhibited a robust 20-30% increase in vascular density and was accompanied by an increase in expression of inhibitor of differentiation-3. There was also an induction of the angiogenesis markers alphaVbeta3 integrin and Del1. Increases in the vascular density of the SLM could be in response to enhanced metabolic activity in this region. This is supported by the induction of glutamine synthetase and the glutamate transporter GLT1.