Gap junctions and communication within the nervous system

Gap junctions are sites on the cellular membrane with intercellular channels build up by twelve protein subunits called connexins. Each connected cell contributes with a hemichannel made up by six connexins subunits. This kind of connection represents and efficient way of intercellular communication in most tissues, including the nervous system. It works as a passage for ions, secondary messenger and metabolites exchange between the cells. In a complex tissue like the nervous tissue they are particularly important because they connect the various cellular types composing a panglial syncytium that performs neuronal protection and tissue homeostasis. The expression of connexins and the intercellular communication through gap junctions are crucial to regulate vital functions as cellular motility, proliferations and survival; changes in the conformational expression of connexins may be involved in diseases as Alzheimer´s disease, neoplasms, bacterial and parasitic infections, or even affect cellular groups when they occur as genetic mutations leading to functional defects of the nervous system as demyelination in the PNS (Charcot-Marie-Tooth disease), hereditary epilepsy, nonsyndromic deafness and senile cataract.

Canine adenovirus type-2 and canine distemper virus pulmonary co-infection in two Chow-Chow puppies with Candida sp esophagitis

Two three-month-old puppies from the same litter were submitted to necropsy after a clinical history of purulent ocular discharge, diarrhoea and coughing. Grossly, the lungs were filled with fluid, firm and diffusely mottled with red and yellow areas. A clumped white-yellowish material with longitudinal stripes was loosely adhered to the esophagus. The histological analysis of the lungs revealed a suppurative and histiocytic broncho-interstitial pneumonia with fibrin, hemorrhage and myriads of eosinophilic intracytoplasmatic and basophilic intranuclear inclusion bodies. The diagnosis was consistent with co-infection by canine adenovirus type-2 and canine distemper virus. Both dogs also had severe proliferative Candida sp. esophagitis. Reports of two concomitant viral diseases and mycotic infection are relatively rare and suggest intrinsic and environmental immunosuppressive factors.

Schwannoma with bone differentiation in a dog

A schwannoma with bone differentiation was diagnosed in a seven-year-old German Shepherd female dog. Clinical signs were those of limping and proprioceptive and neurological deficits. Superficial and deep sensitivity were lower and muscle atrophy of the left forelimb was marked. Two subscapular masses were detected at examination. Microscopic analysis of the masses disclosed a pronounced proliferation of either palisading or loosely arranged within a myxoid tissue spindle neoplastic cells intermingled with bone tissue islands. The neoplasm was positive for vimentin, S100 protein and GFAP.

Malignant histiocytosis in a cat case report

A crossbred 14-year-old castrated male cat had a history of lethargy, anorexia and weight loss of one month evolution. On clinical examination, anemia, emaciation, jaundice and a large mass in the abdomen were detected. Ultrasonography revealed hepatomegaly and a single splenic mass. The cat was submitted to biopsy and euthanatized during the surgical procedure. The diagnosis of malignant histiocytosis was achieved on the basis of the clinical presentation, histopathologic and immunoistochemical findings.