Supplementary immunocytochemistry of hepatocyte growth factor production in activated macrophages early in muscle regeneration

Regenerative intramuscular motor‐innervation is thought to reside in the spatiotemporal expression of axon‐guidance molecules. Our previous studies showed that resident myogenic stem cells, satellite cells, up‐regulate a secreted neural‐chemorepellent semaphorin 3A (Sema3A) during the early‐differentiation period, in response to hepatocyte growth factor (HGF) elevated in injured muscle. However, a paracrine source of the HGF release is still unknown. Very recently, we proposed a possible contribution of anti‐inflammatory macrophages (CD206‐positive M2) by showing that M2 cells infiltrate predominantly at the early‐differentiation phase (3–5 days post‐injury) and produce/secrete large amounts of HGF. However, in understanding this concept there still remains a critical need to examine if phagocytotic pro‐inflammatory macrophages (CD86‐positive M1), another activated‐phenotype still present at the early‐differentiation phase concerned, produce HGF upon muscle injury. The current immunocytochemical study demonstrated that the HGF expression is negative for M1 prepared from cardiotoxin‐injured Tibialis anterior muscle at day 5, in contrast to the intense fluorescent‐signal of M2 served as a positive control. This supplementary result advances our understanding of a spatiotemporal burst of HGF secretion from M2 populations (not M1) to impact Sema3A expression, which ensures a coordinated delay in attachment of motoneuron terminals onto damaged and generating fibers during the early phase of muscle regeneration.     

Lesions associated with plerocerci (Platyhelminthes: Cestoda: Trypanorhyncha) in the gastric wall of a cownose ray, Rhinoptera bonasus (Mitchill), (Myliobatiformes: Rhinopteridae) from the northern Gulf of Mexico

We describe lesions associated with a seemingly intense infection of trypanorhynch plerocerci (Platyhelminthes: Cestoda: Trypanorhyncha) in the gastric wall of a female cownose ray, Rhinoptera bonasus (Myliobatiformes: Rhinopteridae) captured in the northern Gulf of Mexico. Grossly, the multitude of encapsulated, encysted plerocerci imparted a bumpy and cobbled appearance to the serosa of the stomach, and none was observed in any other tissue during routine parasitological necropsy. Histologically, the plerocerci were associated with severe intramural granulomatous gastritis, vascular ectasia and mesothelial polyposis with the exclusion of the mucosa. To our knowledge, this is the first published case study documenting platyhelminth-associated histopathological changes in the gastrointestinal tract of R. bonasus as well as that of the efficacy of immunocytochemical markers for smooth muscle actin, Factor VIII, S-100, and proliferating cell nuclear antigen in Myliobatiformes. It also may serve as a potential primer for much needed ecological investigations regarding the potential role of elasmobranchs as intermediate or 'paratenic' hosts in the life cycles of trypanorhynch cestodes.     

Characterization,cerebral distribution and gonadotropin release activity of neuropeptide Y (NPY) in the goldfish

The presence of a peptide closely related to porcine NPY has been demonstrated in the goldfish brain and pituitary by means of radioimmunoassay (RIA) and high performance liquid chromatography (HPLC). The RIA data demonstrate that displacement curves of brain extracts are parallel to a porcine NPY standard and that in HPLC a compound present in brain extracts is co-eluted with porcine NPY. The distribution of this NPY-like factor within the central nervous system was studied by radioimmunoassay and immunohistochemistry. The results indicated that NPY has a widespread distribution with the highest concentrations being found in the telencephalon and diencephalon. In the pituitary gland, NPY immunoreactive terminals characterized at the electron microscope level were found in the different lobes and, in particular, in close association with the gonadotrophin (GTH) secreting cells. Using anin vitro perifusion system, it was shown that NPY causes a dose dependent increase of GTH release from anterior lobe fragments. These data indicate for the first time in teleosts that NPY is present and widely distributed in the brain and pituitary, and that among other putative functions, could be implicated in the multihormonal release of GTH from the pituitary.     

Feline mesothelioma: case report and review of cytologic,immunocytochemical, histopathologic,and immunohistochemical findings

Mesotheliomas are uncommon neoplasms that arise from mesothelial cells in either the abdominal or thoracic cavities and are rarely diagnosed in cats. A 10-y-old spayed female domestic shorthair cat was presented to the Louisiana State University oncology service for evaluation of a large amount of abdominal effusion. Abdominal ultrasound identified a large mesenteric mass with numerous ill-defined nodules. An abdominocentesis was performed with cytologic and immunocytochemical findings consistent with a neoplastic effusion, with large clusters of epithelioid cells that exhibited strong cytoplasmic expression of pancytokeratin, vimentin, and Wilms tumor 1 antigens. Further testing was declined, and meloxicam was prescribed until the cat died 23 d after initial presentation. Upon postmortem examination, the omentum was contracted into a firm mass adhered to multiple organs and accompanied by numerous small white nodules throughout the abdominal cavity. On histopathology and immunohistochemistry, neoplastic cells were found throughout the abdominal cavity; 60–95% exhibited moderate-to-strong cytoplasmic immunoreactivity for cytokeratin, vimentin, and Wilms tumor 1 protein. The final diagnosis was an epithelioid mesothelioma. Our case illustrates the utility of cytology, immunocytochemistry, and its relation to histology and immunohistochemistry. We also reviewed the reported cases of feline mesothelioma.