Radiomic biomarkers informative of cancerous transformation in neurofibromatosis-1 plexiform tumors.

BACKGROUND: This study explores whether objective, quantitative radiomic biomarkers derived from magnetic resonance (MR), positron emission tomography (PET), and computed tomography (CT) may be useful in reliably distinguishing malignant peripheral nerve sheath tumors (MPNST) from benign plexiform neurofibromas (PN). METHODS: A registration and segmentation pipeline was established using a cohort of NF1 patients with histopathological diagnosis of PN or MPNST, and medical imaging of the PN including MR and PET-CT. The corrected MR datasets were registered to the corresponding PET-CT via landmark-based registration. PET standard-uptake value (SUV) thresholds were used to guide segmentation of volumes of interest: MPNST-associated PET-hot regions (SUV≥3.5) and PN-associated PET-elevated regions (2.0

Principles for valid histopathologic scoring in research.

Histopathologic scoring is a tool by which semiquantitative data can be obtained from tissues. Initially, a thorough understanding of the experimental design, study objectives, and methods is required for the pathologist to appropriately examine tissues and develop lesion scoring approaches. Many principles go into the development of a scoring system such as tissue examination, lesion identification, scoring definitions, and consistency in interpretation. Masking (aka "blinding") of the pathologist to experimental groups is often necessary to constrain bias, and multiple mechanisms are available. Development of a tissue scoring system requires appreciation of the attributes and limitations of the data (eg, nominal, ordinal, interval, and ratio data) to be evaluated. Incidence, ordinal, and rank methods of tissue scoring are demonstrated along with key principles for statistical analyses and reporting. Validation of a scoring system occurs through 2 principal measures: (1) validation of repeatability and (2) validation of tissue pathobiology. Understanding key principles of tissue scoring can help in the development and/or optimization of scoring systems so as to consistently yield meaningful and valid scoring data.

Ferret lung transplant: an orthotopic model of obliterative bronchiolitis.

Obliterative bronchiolitis (OB) is the primary cause of late morbidity and mortality following lung transplantation. Current animal models do not reliably develop OB pathology. Given the similarities between ferret and human lung biology, we hypothesized an orthotopic ferret lung allograft would develop OB. Orthotopic left lower lobe transplants were successfully performed in 22 outbred domestic ferrets in the absence of immunosuppression (IS; n = 5) and presence of varying IS protocols (n = 17). CT scans were performed to evaluate the allografts. At intervals between 3-6 months the allografts were examined histologically for evidence of acute/chronic rejection. IS protects allografts from acute rejection and early graft loss. Reduction of IS dosage by 50% allowed development of controlled rejection. Allografts developed infiltrates on CT and classic histologic acute rejection and lymphocytic bronchiolitis. Cycling of IS, to induce repeated episodes of controlled rejection, promoted classic histologic hallmarks of OB including fibrosis-associated occlusion of the bronchiolar airways in all allografts of long-term survivors. In conclusion, we have developed an orthotopic lung transplant model in the ferret with documented long-term functional allograft survival. Allografts develop acute rejection and lymphocytic bronchiolitis, similar to humans. Long-term survivors develop histologic changes in the allografts that are hallmarks of OB.

A forensic investigation into the etiology of bat mortality at a wind farm: barotrauma or traumatic injury?

Migrating bats have increased mortality near moving turbine blades at wind farms. The authors evaluated competing hypotheses of barotrauma and traumatic injury to determine the cause. They first examined the utility of lungs from salvaged bat carcasses for histopathologic diagnosis of barotrauma and studied laboratory mice as a model system. Postmortem time, environmental temperature, and freezing of carcasses all affected the development of vascular congestion, hemorrhage, and edema. These common tissue artifacts mimicked the diagnostic criteria of pulmonary barotrauma; therefore, lung tissues from salvaged bats should not be used for barotrauma diagnosis. The authors next compared wind farm (WF) bats to building collision (BC) bats collected near downtown Chicago buildings. WF bats had an increased incidence in fracture cases and specific bone fractures and had more external lacerations than BC bats. WF bats had additional features of traumatic injury, including diaphragmatic hernia, subcutaneous hemorrhage, and bone marrow emboli. In summary, 73% (190 of 262) of WF bats had lesions consistent with traumatic injury. The authors then examined for ruptured tympana, a sensitive marker of barotrauma in humans. BC bats had only 1 case (2%, 1 of 42), but this was attributed to concurrent cranial fractures, whereas WF bats had a 20% (16 of 81) incidence. When cases with concurrent traumatic injury were excluded, this yielded a small fraction (6%, 5 of 81) of WF bats with lesions possibly consistent with barotrauma etiology. Forensic pathology examination of the data strongly suggests that traumatic injury is the major cause of bat mortality at wind farms and, at best, barotrauma is a minor etiology.

Fluorescence in situ hybridization for identification of Tritrichomonas foetus in formalin-fixed and paraffin-embedded histological specimens of intestinal trichomoniasis.

In the present study a highly species-specific oligonucleotide sequence of Tritrichomonas foetus 18S rRNA was used to design an antisense probe for identification of T. foetus in formalin-fixed and paraffin-embedded histological specimens by means of fluorescence in situ hybridization (FISH). Using archival histological specimens from several species with light microscopic evidence of intestinal trichomoniasis, and under optimized hybridization conditions, the probe positively identified trichomonads in colonic specimens from piglets and a kitten with PCR-confirmed T. foetus infection. Neither positive hybridization of the probe or PCR amplification of T. foetus DNA was observed in histological specimens from hamster (Tritrichomonas muris), turkey, nor mouse (Entamoeba muris) intestinal protozoal infections. Sequence-specific binding of the probe was further verified by successfully out-competing the hybridization with 10 x molar excess unlabeled probe and failure of a labeled sense probe to hybridize. The FISH assay described here enables simultaneous location and molecular identification of T. foetus in formalin-fixed and paraffin-embedded histological specimens of intestinal trichomoniasis. The methods employed are likely to also be applicable to probes designed for specific recognition of other trichomonad species, especially in mammalian tissue where red blood cell auto-fluorescence can be easily differentiated from the hybridization signal of trichomonads.

Alcian Blue and Pyronine Y histochemical stains permit assessment of multiple parameters in pulmonary disease models.

Utilization of a combined Alcian Blue and Pyronine Y histochemical method for the assessment of multiple parameters in the respiratory tract of various species is described. Acidic mucins were deep blue (sialylated mucins), red (sulfated mucins), or variably purple (mixture of sialylated/sulfated mucins), and differential mucus production was readily detected in a murine respiratory syncytial virus vaccine model of pulmonary inflammation. Elastic fibers stained red in the walls of pulmonary arteries, connecting airways, alveolar septa, and subpleural interstitium. Mast cells had red to red-purple granular cytoplasmic staining. Nuclei were ubiquitously counterstained pale blue. Representative staining was detected in tissues from multiple species, including inbred mice, rats, ferrets, cats, dogs, sheep, and pigs. The fluorescent property of the stained tissues offers additional modalities with which to analyze tissue sections. This histochemical technique detects multiple critical parameters in routine paraffin sections of lung tissue, reduces the need for repeated serial sectioning and staining, and is cost-effective and simple to perform.

Regulation of surfactant protein and defensin mRNA expression in cultured ovine type II pneumocytes by all-trans retinoic acid and VEGF.

Beta-defensins and surfactant proteins are components of the pulmonary innate immune system. Their gene expression is regulated by development, hormones, growth and immunoregulatory factors. It was our hypothesis that growth and differentiation factors such as all-trans retinoic acid (RA) and vascular endothelial growth factor (VEGF) may affect expression of selected innate immune genes by respiratory epithelial cells. Ovine JS7 cells (alveolar type II pneumocytes) were incubated in serum-free Dulbecco's modified Eagle's medium (DMEM) complete media that contained: no treatment (negative control), RA (500 nM), or VEGF (100 ng/ml) for 6, 12 or 24 h incubation. Total RNA was isolated, cDNA synthesized, and relative mRNA levels of surfactant protein A (SP-A) and SP-D, and sheep beta-defensin-1 (SBD-1) were determined by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Cells had significantly increased expression of SP-D mRNA at 6 h and 24 h, decreased expression of SP-A mRNA at 12 h, and unchanged levels of SBD-1 mRNA after the treatment with RA compared with their respective negative controls. VEGF did not alter the expression of the three innate immune genes. These findings suggest that SP-A and SP-D have different transcription regulation pathways, and that expression of SBD-1 is not inducible by RA similar to its human homolog HBD-1. The lack of changes induced by VEGF treatment suggests that VEGF does not have a direct effect on epithelial cells, but may affect gene expression indirectly.

Collectins and cationic antimicrobial peptides of the respiratory epithelia.

The respiratory epithelium is a primary site for the deposition of microorganisms that are acquired during inspiration. The innate immune system of the respiratory tract eliminates many of these potentially harmful agents preventing their colonization. Collectins and cationic antimicrobial peptides are antimicrobial components of the pulmonary innate immune system produced by respiratory epithelia, which have integral roles in host defense and inflammation in the lung. Synthesis and secretion of these molecules are regulated by the developmental stage, hormones, as well as many growth and immunoregulatory factors. The purpose of this review is to discuss antimicrobial innate immune elements within the respiratory tract of healthy and pneumonic lung with emphasis on hydrophilic surfactant proteins and beta-defensins.

Monocytic/macrophagic pneumonitis after intrabronchial deposition of vascular endothelial growth factor in neonatal lambs.

Preterm and young neonates are prone to inadequate surfactant production and are susceptible to respiratory distress syndrome characterized by alveolar damage and hyaline-membrane formation. Glucocorticoid therapy is commonly used in preterm and young infants to enhance lung maturation and surfactant synthesis. Recently, vascular endothelial growth factor (VEGF) was suggested to be a novel therapeutic agent for lung maturation that lacked adverse effects in mice. The purpose of this study was to assess the safety of incremental concentration (0.0005, 0.005, and 0.05 mg/ml) and duration (16, 24, and 32 hours) of recombinant human VEGF after bronchoscopic instillation (10 ml) in neonatal lambs. High-dose VEGF caused locally extensive plum-red consolidation that was microscopically characterized by interstitial and alveolar infiltrates of cells that were morphologically and phenotypically (CD68+) consistent with monocytes/macrophages. T cells (CD3+) and B cells (CD79+) were located primarily in bronchus/bronchiole-associated lymphoid tissue and were not consistently altered by treatment with VEGF. The dose of VEGF had significant effects on both gross lesions (P < .0047) and microscopic monocyte/macrophage recruitment scores (P < .0001). Thus, the VEGF dose instilled into the lung greatly influenced cellular recruitment and lesion development. The post-dosing interval of VEGF in this study had minor impact (no statistical significance) on cellular recruitment. This study showed that airway deposition of VEGF in the neonatal lamb induces monocyte/macrophage recruitment to the lung and high doses can cause severe lesions. The cellular recruitment suggests further research is needed to define dosages that are efficacious in enhancing lung maturation while minimizing potential adverse effects.

Unilateral perinephric pseudocyst secondary to hydronephrosis in a C57BL/6J mouse.

A 9-month-old C57BL/6J mouse had progressive abdominal distension over a 1-week period, and a distended left renal capsule was discovered at postmortem examination. Incision of the capsule showed a tan, cloudy fluid that separated the renal capsule and the remnant left kidney. Microscopically, the capsule was significantly separated from the renal parenchyma by clear space and necrotic cellular debris. The majority of the lining of the renal capsule was composed of fibrous connective tissue and lacked an epithelial lining, consistent with a subcapsular perinephric pseudocyst. In addition, attached to intermittent portions of the renal capsule were thin rims of compressed cortical tissue lined by transitional epithelium. The finding of remnant cortical tissue lined by transitional epithelium is consistent with severe hydronephrosis and indicates that the hydronephrosis preceded the formation of the perinephric pseudocyst. To our knowledge, this is the first case report to characterize a perinephric pseudocyst secondary to severe hydronephrosis in a mouse.

Congenital fetal rhabdomyoma in a foal.

An Appaloosa filly was born with a ventral midline, approximately 8 x 12 x 15 cm subcutaneous cervical mass. The nonencapsulated mass was composed of interlacing and haphazard bundles of spindle cells on moderate to abundant loose myxomatous stroma. A moderate number of cells showed cross striations with minor nuclear variation and a low mitotic rate. Immunohistochemical staining for myoglobin, desmin, actin, vimentin, and S-100 was positive and negative for glial fibrillar antigen and keratin. Rhabdomyomas are rare benign tumors of striated muscle. Rhabdomyomas described previously in the veterinary literature are analogous to the "adult form" of human rhabdomyoma. This is the first report of a veterinary case that 1) clinically and histologically parallels the "fetal form" in human rhabdomyoma and 2) describes a congenital extracardiac rhabdomyoma.

Solitary retinal astrocytoma in a dog.

An intraocular mass from a 13-year old Husky-mix dog was diagnosed as retinal astrocytoma. The mass arose from the ganglion layer of the retina and occupied 50% of the vitreous space. The mass was immunoreactive for neuron-specific enolase, S-100, vimentin, and glial fibrillary acidic protein. The neoplasm had characteristics similar to solitary retinal astrocytomas of humans but lacked the marked vascularity.

Comparison of early ileal invasion by Salmonella enterica serovars Choleraesuis and Typhimurium.

The mechanisms of Salmonella serovar-host specificity are not well defined. Pig ileal loops were used to compare phenotypic differences in early cellular invasion between non-host-adapted Salmonella serovar Typhimurium (SsT) and host-adapted Salmonella serovar Choleraesuis (SsC). By 10 minutes postinoculation, both serovars invaded a small number of M cells, enterocytes, and goblet cells. Multiple SsC organisms (up to 6 per cell) simultaneously invaded M cells, whereas SsT often invaded as one to two organisms per M cell. Internalization of both serovars resulted in vacuoles containing a single bacterium. The follicle-associated epithelium (FAE) of SsC-inoculated loops responded with more filopodia and lamellipodia although exhibiting less cell swelling than SsT. Additionally, SsT showed an enhanced affinity for sites of cell extrusion compared with SsC at 60 minutes. These results suggest: 1) both SsC and SsT exhibit non-cell-specific invasion as early as 10 minutes postinoculation, 2) Salmonella serovars exhibit differences in early invasion of FAE and M cells, and 3) cells undergoing extrusion may provide a site for preferential adherence by SsT and SsC.

Early epithelial invasion by Salmonella enterica serovar Typhimurium DT104 in the swine ileum.

Salmonella enterica serovar Typhimurium is an important intestinal pathogen in swine. This study was performed to document the early cellular invasion of Salmonella serovar Typhimurium in swine ileum. Ileal gut-loops were surgically prepared in ten 4- to 5-week-old mixed-breed pigs and inoculated for 0-60 minutes. Loops were harvested and prepared for both scanning and transmission electron microscopy (SEM and TEM, respectively). Preferential bacterial adherence to microfold cells (M cells) was seen within 5 minutes, and by 10 minutes bacterial invasion of the apical membrane was seen in M cells, goblet cells, and enterocytes. This multicellular invasion was observed throughout the course of infection. In addition, SEM revealed a specific affinity of Salmonella serovar Typhimurium to sites of cell extrusion. Using TEM, bacteria in these areas were focused in the crevices formed by the extruding cell and the adjacent cells and in the cytoplasm immediately beneath the extruding cell. Our results suggest that early cellular invasion by Salmonella serovar Typhimurium is nonspecific and rapid in swine. Furthermore, the combination of SEM and TEM data suggests that Salmonella serovar Typhimurium may use sites of cell extrusion as an additional mechanism for early invasion.

Secretion of a putative cytotoxin in multiple antibiotic resistant Salmonella enterica serotype Typhimurium phagetype DT104.

Salmonella enterica serotype Typhimurium phagetype DT104 (DT104) is a multiple antibiotic-resistant pathogen. DT104 infections have been reported in a multitude of hosts including humans, companion animals, livestock and wildlife. Recently, several isolates of DT104 were recovered from veal calves exhibiting abomasitis, a finding that is inconsistent with classic salmonellosis. One of these isolates was used in murine ligated loop experiments where it was observed that multiresistant DT104 can elaborate a putative cytotoxin. Thus it appears that DT104 has the ability to evade pharmacologic interventions, via antibiotic resistance, and elaborate a toxin that can damage cells.