Epithelioid hemangiosarcomas of the bovine urinary bladder: a histologic, immunohistochemical, and ultrastructural examination of four tumors

Molecular mechanisms of hypoxia in cancer

PURPOSE

Hypoxia is a condition of insufficient oxygen to support metabolism which occurs when the vascular supply is interrupted, or when a tumour outgrows its vascular supply. It is a negative prognostic factor due to its association with an aggressive tumour phenotype and therapeutic resistance. This review provides an overview of hypoxia imaging with Positron emission tomography (PET), with an emphasis on the biological relevance, mechanism of action, highlighting advantages, and limitations of the currently available hypoxia radiotracers.

METHODS

A comprehensive PubMed literature search was performed, identifying articles relating to biological significance and measurement of hypoxia, MRI methods, and PET imaging of hypoxia in preclinical and clinical settings, up to December 2016.

RESULTS

A variety of approaches have been explored over the years for detecting and monitoring changes in tumour hypoxia, including regional measurements with oxygen electrodes placed under CT guidance, MRI methods that measure either oxygenation or lactate production consequent to hypoxia, different nuclear medicine approaches that utilise imaging agents the accumulation of which is inversely related to oxygen tension, and optical methods. The advantages and disadvantages of these approaches are reviewed, along with individual strategies for validating different imaging methods. PET is the preferred method for imaging tumour hypoxia due to its high specificity and sensitivity to probe physiological processes in vivo, as well as the ability to provide information about intracellular oxygenation levels.

CONCLUSION

Even though hypoxia could have significant prognostic and predictive value in the clinic, the best method for hypoxia assessment has in our opinion not been realised.

The urothelium: anatomy, review of the literature, perspectives for veterinary medicine

Over time, much knowledge has been accumulated about the active role of the urothelium, principally in rodents and human. Far from being a mere passive barrier, this specialized epithelium can alter the ion and protein composition of the urine, is able to sense and respond to mechanical stimuli such as pressure, and react to mechanical stimuli by epithelial cell communication with the nervous system. Most of the specialized functions of the urothelium are linked to a number of morpho-physiologic properties exhibited by the superficial umbrella cells, including specialized membrane lipids, asymmetric unit membrane particles and a plasmalemma with stiff plaques which function as a barrier to most substances found in urine, thus protecting the underlying tissues. Moreover, the entire mucosa lining the low urinary tract, composed of urothelium and sub-urothelium, forms a functional transduction unit, able to respond to eso- and endogenous physical and chemical stimuli in a manner assuring an adequate functional response. This review will summarize the available information on each area of inquiry from a morpho-functional point of view. Possible considerations pertaining to species of veterinary interest are reviewed as well. The review was prepared consulting the electronic databases PubMed and Cab Abstracts and retrieving all pertinent reports and the relative reference lists, in order to identify any potential additional studies that could be included. Full-length research articles and thematic reviews were considered. Information on the urothelium of some domestic animal species was also included.

Paraparesis in a Golden Retriever

A 7-year-old female spayed Golden Retriever dog presented with fever and a 10-day history of neurological signs, including ambulatory paraparesis and pelvic limb ataxia. Neurological examination initially revealed a T3-L3 myelopathy. Thoracic radiographs revealed a diffuse miliary pulmonary pattern. Endotracheal washes and fine-needle aspirates from several organs aimed at identifying a potential infectious agent or neoplastic process were all unsuccessful. Due to worsening of the clinical signs, euthanasia was elected. Necropsy findings included multifocal, pale to dark red, firm nodules infiltrating the lungs, heart, mesentery, pancreas, small intestine, brain, and spinal cord. Cytological examination of impression smears obtained from the pulmonary nodules during necropsy revealed clusters of epithelioid cells admixed with fewer spindle cells, erythrocytes, and scattered leukocytes. Clinical signs and cytological findings initially suggested the possibility of a widespread granulomatous disease or a metastatic epithelial neoplasm as possible clinical differentials in this case. The final diagnosis was based on the gross and histological findings, with confirmation following histochemistry and immunohistochemistry.

Bovine papillomavirus type 2 infection and a series of mesenchymal tumors of the urinary bladder in cattle

This report describes the histopathology of two hundred and fifty-three mesenchymal tumors of the urinary bladder in cattle grazing on lands rich in bracken fern. Approximately 80% were hemangiomas and angiosarcomas. Hemangioma (capillary, cavernous, and large vessels) was the most frequent mesenchymal tumor and was more common than angiosarcoma. Although the appearance of endothelial cells can vary remarkably, epithelioid angiosarcomas, often containing multinucleated cells, were the most frequent malignant vascular tumors. Hemangiopericytoma and tumors of muscle and soft connective tissue origin, alone and/or in association with tumor-like lesions, were less frequently seen. Furthermore, forty-five cases of intravascular papillary endothelial hyperplasia (IPEH), a lesion not previously reported in the urinary bladder of cattle, were also described. Bovine papillomavirus type-2 DNA was amplified in tumor samples. Forty vascular tumors were investigated by dual-labeling immunofluorescence, and, for the first time, a coexpression of E5 and platelet-derived growth factor β receptor (PDGFβR) was shown to occur. The results show that the BPV-2 E5 oncoprotein binds to the activated form of the PDGFβ receptor thus playing an important role in mesenchymal as well as epithelial carcinogenesis of the urinary bladder. Furthermore, these findings demonstrate that BPV-2 infects both epithelial and mesenchymal cells.

Acute compartment syndrome in the pelvic limb of a cow following biopsy of a skeletal muscle-associated hemangiosarcoma

CASE DESCRIPTION

A 6-year-old Holstein cow was examined because of chronic lameness and swelling near the stifle joint of the left pelvic limb.

CLINICAL FINDINGS

A mass was palpated in the soft tissues lateral to the proximal aspect of the left tibia. Multiple attempts to obtain a biopsy specimen of the mass resulted in acute compartment syndrome of the femoral compartment (tensor fasciae latae and biceps femoris muscles) and lateral tibial compartment (cranial tibial and peroneus tertius muscles) with associated sciatic nerve paralysis.

TREATMENT AND OUTCOME

Surgical decompression via tensor fasciae latae and biceps femoris incision resolved the sciatic nerve paralysis. On the fifth day following surgery, the cow began to develop signs of increased respiratory effort. Thoracic radiography revealed a pulmonary metastatic micronodular pattern. The cow was euthanized because its condition deteriorated. Metastatic hemangiosarcoma was confirmed at necropsy, and the primary tumor was the mass that was lateral to the tibia and within the biceps femoris muscle.

CLINICAL RELEVANCE

Hemangiosarcoma should be considered a differential diagnosis for lameness in cattle when no orthopedic cause can be identified. Close patient surveillance is strongly recommended in the event that a vascular tumor is present because catastrophic consequences are possible. To our knowledge, this is the first report of acute compartment syndrome in a pelvic limb of a bovine patient and the only report of hemangiosarcoma in the skeletal muscle of cattle.

Bracken-associated human and animal health hazards: chemical, biological and pathological evidence

Bracken (Pteridium aquilinum) is a widely distributed carcinogenic fern, to whose toxins human populations are exposed through multiple routes. Animals are also affected by bracken toxins, leading to serious production losses yearly. Accordingly, several governmental reports regarding the safeguard of public health against bracken carcinogens have been recently issued. This review describes the main bioactive compounds identified in bracken and their biological effects at the molecular, cellular, pathological and populational levels, with particular emphasis on ptaquiloside, the main bracken carcinogen. Recent biopathological studies shedding further light on the genotoxicity immunotoxicity and carcinogenicity of ptaquiloside are discussed. Key steps on the long effort to understand bracken toxicology are also reviewed, along with the latest findings on new bracken toxins and human exposures routes. The presence of ptaquiloside and related terpene glycosides in milk, meat and water are of particular concern from the viewpoints of both human and animal health.