Cutaneous and renal glomerular vasculopathy as a cause of acute kidney injury in dogs in the UK.

To describe the signalment, clinicopathological findings and outcome in dogs presenting with acute kidney injury (AKI) and skin lesions between November 2012 and March 2014, in whom cutaneous and renal glomerular vasculopathy (CRGV) was suspected and renal thrombotic microangiopathy (TMA) was histopathologically confirmed. The medical records of dogs with skin lesions and AKI, with histopathologically confirmed renal TMA, were retrospectively reviewed. Thirty dogs from across the UK were identified with clinicopathological findings compatible with CRGV. These findings included the following: skin lesions, predominantly affecting the distal extremities; AKI; and variably, anaemia, thrombocytopaenia and hyperbilirubinaemia. Known causes of AKI were excluded. The major renal histopathological finding was TMA. All thirty dogs died or were euthanised. Shiga toxin was not identified in the kidneys of affected dogs. Escherichia coli genes encoding shiga toxin were not identified in faeces from affected dogs. CRGV has previously been reported in greyhounds in the USA, a greyhound in the UK, without renal involvement, and a Great Dane in Germany. This is the first report of a series of non-greyhound dogs with CRGV and AKI in the UK. CRGV is a disease of unknown aetiology carrying a poor prognosis when azotaemia develops.

Diagnostic utility of PAX8, TTF-1 and napsin A for discriminating metastatic carcinoma from primary adenocarcinoma of the lung.

TTF-1 and napsin A are useful biomarkers for differentiating primary lung adenocarcinoma from metastatic tumors. Studies have shown, however, that TTF-1 and napsin A also can be expressed in extrapulmonary carcinomas, and that a small fraction of primary lung adenocarcinomas do not co-express these two markers. We attempted to determine whether a tissue-specific transcriptional factor, PAX8, can help determine primary sites of lung carcinomas. Immunohistochemical stains for PAX8, TTF-1 and napsin A were performed on 103 cases of metastatic lung carcinomas from a variety of origins and 120 cases of primary lung adenocarcinomas. Our data demonstrated that all 103 metastatic carcinomas were negative for napsin A, while 14 (13.6%; four thyroid, two endometrium, three colon, one prostate, one salivary adenoid cystic, two renal cell carcinomas, and one ovary) showed weak to strong TTF-1 nuclear staining in 5-60% of the tumor cells. All primary lung adenocarcinomas were negative for PAX8, whereas 46 (44.7%) metastatic carcinomas from the kidney (29/33), ovary (6/8), endometrium (5/5), endocervix (1/1), thyroid (4/5) and urinary tract (1/3) were positive for PAX8. Our data demonstrate that of combined use of PAX8, TTF-1 and napsin A is reliable to separate reliably lung primary from metastatic tumors.

Metastatic endometrial stromal sarcoma of the lung: importance of immunohistochemical staining, clinical history and imaging studies.

Proper evaluation of lung nodules is a difficult issue for clinical management of patients. Discriminating metastatic endometrial stromal sarcoma (ESS) from other primary spindle cell neoplasms of the lung using histological analysis can be challenging. This is particularly true when an adequate clinical history is lacking, because ESS metastasis can be delayed by a couple of decades. To emphasize the importance of the correlation of pathological findings with clinical history and imaging studies, we investigated 11 cases of ESS (seven low grade and four high grade) metastatic to the lung. All cases presented with one to multiple unilateral or bilateral lung nodules that were detected by chest computed tomography. Primary ESS was diagnosed from hysterectomy specimens except for one by endometrial biopsy, 0.5 to 23 years prior to metastasis. Immunohistochemical studies showed that all ESS cases were moderately to strongly positive for Bcl-2 and CD10 with >50% of tumor cells stained, except for one high grade ESS that was negative for CD10. Eight (72.7%) and seven (63.6) of the 11 cases showed positive estrogen and progesterone receptors, respectively, with a majority of positive cases showing diffuse and moderate to strong staining. Strong but patchy staining for CD34 was detected in one (9.1%) case with smooth muscle differentiation. CK7 and TTF-1 were negative in all cases. Two (18.2%) cases exhibited patchy and strong positivity for caldesmon. Two (18.2%) low grade ESS cases showed moderate to strong AE1/AE3 positivity in >50% of tumor cells, one of which also showed moderate CK19 and Cam 5.2 staining in >30% of tumor cells. One should be cautious when assessing spindle cell neoplasms of the lung in women with a history of hysterectomy. Correlation of clinical history and imaging studies with histological and immunohistochemical findings is essential to diagnosis of metastatic ESS to the lung.

Expression of Toll-like receptor 2 in duodenal biopsies from dogs with inflammatory bowel disease is associated with severity of disease.

There is growing evidence that aberrant innate immune responses towards the bacterial flora of the gut play a role in the pathogenesis of canine inflammatory bowel disease (IBD). Toll-like receptors (TLR) play an important role as primary sensors of invading pathogens and have gained significant attention in human IBD as differential expression and polymorphisms of certain TLR have been shown to occur in ulcerative colitis (UC) and Crohn's disease (CD). The aim of the current study was to evaluate the expression of two TLR important for recognition of commensals in the gut. TLR2 and TLR4 mRNA expression in duodenal biopsies from dogs with IBD was measured and correlated with clinical and histological disease severity. Endoscopic duodenal biopsies from 20 clinical cases and 7 healthy control dogs were used to extract mRNA. TLR2 and TLR4 mRNA expression was assessed using quantitative real-time PCR. TLR2 mRNA expression was significantly increased in the IBD dogs compared to controls, whereas TLR4 mRNA expression was similar in IBD and control cases. In addition, TLR2 mRNA expression was mildly correlated with clinical severity of disease, however, there was no correlation between TLR2 expression and histological severity of disease.

A finite element prediction of strain on cells in a highly porous collagen-glycosaminoglycan scaffold.

Tissue engineering often involves seeding cells into porous scaffolds and subjecting the scaffold to mechanical stimulation. Current experimental techniques have provided a plethora of data regarding cell responses within scaffolds, but the quantitative understanding of the load transfer process within a cell-seeded scaffold is still relatively unknown. The objective of this work was to develop a finite element representation of the transient and heterogeneous nature of a cell-seeded collagen-GAG-scaffold. By undertaking experimental investigation, characteristics such as scaffold architecture and shrinkage, cellular attachment patterns, and cellular dimensions were used to create a finite element model of a cell-seeded porous scaffold. The results demonstrate that a very wide range of microscopic strains act at the cellular level when a sample value of macroscopic (apparent) strain is applied to the collagen-GAG-scaffold. An external uniaxial strain of 10% generated a cellular strain as high as 49%, although the majority experienced less than approximately 5% strain. The finding that the strain on some cells could be higher than the macroscopic strain was unexpected and proves contrary to previous in vitro investigations. These findings indicate a complex system of biophysical stimuli created within the scaffolds and the difficulty of inducing the desired cellular responses from artificial environments. Future in vitro studies could also corroborate the results from this computational prediction to further explore mechanoregulatory mechanisms in tissue engineering.

Biomechanics and mechanobiology in osteochondral tissues.

Osteochondral tissues are those that form the synovial joints, namely cartilage and bone, including sub-chondral bone. The biomechanical purpose of synovial joints is to provide lubricated contact between the moving surfaces with as little frictional forces as possible. This is achieved by separating the cartilage layers by a thin film of fluid and supporting the cartilage layers by a bony trabecular network that becomes dense and more calcified immediately underneath the cartilage layer. Each tissue's biomechanical behavior is well understood after several decades of research and this behavior is briefly reviewed here, as are the concepts relating to the mechanical induction of cartilage degradation (osteoarthritis) with a discussion of clinical strategies for repair. Focusing on tissue-engineering strategies, the following concepts are reviewed: scaffolds, bioreactors and computational simulations, with an analysis of how these elements may be combined in future.