Receptors for excitatory amino acids on neurons in rat pyriform cortex

The actions of a variety of agonists and antagonists of the excitatory amino acids on rat pyriform cortex pyramidal neurons were studied in a submerged, perfused brain slice. The order of potency for the agonists, applied by ionophoresis, was kainate greater than quisqualate greater than N-methyl-D-aspartate greater than aspartate = glutamate. The endogenous monosynaptic excitation of pyramidal neurons upon stimulation of the lateral olfactory tract was blocked post-synaptically by DL-2-amino-4-phosphonobutyric acid, although this drug did not consistently block any of the exogenous responses. The synaptic excitation was not blocked, however, by antagonists presumed specific for the quisqualate (glutamate diethyl ester), kainate, (gamma-D-glutamylglycine), or N-methyl-D-aspartate (DL-2-amino-5-phosphonovaleric acid, DL-2-amino-7-phosphonohetaonic acid) receptors. Several antagonists blocked N-methyl-D-aspartate responses at lower concentrations than those to aspartate, and other antagonists distinguished between kainate and quisqualate responses. These results suggest that 1) pyriform neurons have a variety of receptors that have properties somewhat different from those found in other preparations and 2) the endogenous transmitter activates a receptor distinct from those activated by kainate, quisqualate, and N-methyl-D-aspartate.     

Heterogeneity of the MtTW15 mammosomatotropic tumor. I. Light microscopic evaluation of cell types by means of immunocytochemistry,morphometric quantitation,fluorescence cytophotometry and radioimmunoassay

Large MtTW₁₅ pituitary tumors produced 200- to 800-fold elevations in serum growth hormone (GH) and prolactin (PRL) levels. Female tumor hosts showed doubling in body weight, milk secretion, and a 2-fold hepatosplenomegaly. Pituitaries of host animals were reduced by about 50% in both weight and concentrations of GH and PRL. Large tumors were well-encapsulated, multinodular and showed variable amounts of necrosis and hemorrhage. Cytofluorometric analysis revealed a range of 100-fold in nuclear DNA content of tumor parenchymal cells which were chromophobic, pleomorphic and frequently mitotic. Concentrations of hormones in tumors were less than in normal pituitaries and highly variable with the ratio of GH/PRL ranging up to 30-fold within the same tumor. Immunostaining and linear scanning quantitation showed that about 50% of the tumor cells contained immunodetectable hormones. Comparison of immunostained adjacent sections showed that hormone-containing tumor cells were pleomorphic, unequally distributed within nodules, lacking in distinctive identifying morphological characteristics and that they contained GH or PRL but not both hormones simultaneously. Collectively our results show that large MtTW₁₅ tumors are comprised of a markedly heterogeneous population of tumor cells and they suggest that the hormone-containing cells are monohormonal secreting tumor cells which can produce GH or PRL but not both hormones.     

Characterization of primary cell cultures as potential target cells for analysis of bovine cytotoxic T lymphocytes

In domestic animal species, assessment of cell-mediated immune responses to virus infection is hampered by the requirement for class I MHC compatibility between target and effector cells. Additional complicating factors can include an inability to infect target cells in vitro, or virus-induced lysis of infected target cells. One way to circumvent these problems is to use virus-mediated gene transfer to deliver individual viral genes to autologous primary target cells. Several primary bovine cell cultures were assessed as potential target cells for cytotoxic T lymphocyte (CTL) assays by measuring their levels of class I MHC expression and susceptibilities to retroviral gene delivery. High levels in both class I MHC expression and susceptibility to gene delivery were seen in adherent cell cultures isolated from peripheral blood (PBAC). PBAC, which arose as an outgrowth of adherent peripheral blood mononuclear cell cultures, had morphology, protein expression patterns, and response to functional assays characteristic of high endothelial cells. Expression of viral vector-delivered genes in PBAC cells was confirmed with a recombinant retrovirus carrying the green fluorescent protein (GFP) gene. The use of vector-mediated delivery of viral genes to bovine high endothelial cells is a promising method for assessment of cell-mediated immunity in cattle.     

Interposition Ankle Arthroplasty Using Acellular Dermal Matrix: A Small Series

Although ankle arthrodesis is the reference standard for end-stage ankle arthritis, loss of mobility and adjacent joint arthritis are consequences that alternatives to arthrodesis attempt to avoid. The purpose of the present study was to report the clinical results of interpositional arthroplasty using acellular dermal matrix in 4 patients (age 32 to 42 years) for the treatment of advanced ankle osteoarthritis. The primary findings included relief of pain, with improvement in tibiotalar joint range of motion from a mean of 16.5° (range 0° to 24°) preoperatively to a mean of 31° (range 25° to 40°) postoperatively. All 4 patients underwent open arthrotomy of the anterior and posterior tibiotalar capsule with plafond exostectomy and debridement of all deleterious tissue within the ankle capsule. The articular surface of the talar dome was denuded down to smooth subchondral bone, and microfracture was performed. Autologous calcaneal bone marrow aspirate was applied, and talar resurfacing was achieved using an acellular dermal matrix. Knotless anchors placed medially and laterally within the anterior and posterior dome were used to affix the dermal matrix. The follow-up period ranged from 12 to 18 (mean 14) months. The mean pre- and 12-month postoperative Association of Orthopaedic Foot and Ankle Society hindfoot-ankle scale scores were 35 and 88.5, respectively. These outcomes suggest that interpositional tibiotalar arthroplasty using an acellular dermal matrix is successful in improving function and range of motion and decreasing pain. As an alternative to tibiotalar arthrodesis, interpositional tibiotalar arthroplasty might be the procedure of choice for young patients with end-stage ankle arthritis. Longer follow-up periods, histologic testing, and arthroscopic evaluations would be advantageous to further assess the durability of this procedure.     

One-year pivotal trial outcomes of the Nellix system for endovascular aneurysm sealing

Objective

The Nellix EndoVascular Aneurysm Sealing (EVAS) System (Endologix, Inc, Irvine, Calif) is a novel approach to abdominal aortic aneurysm (AAA) treatment whereby polymer is used to fill the AAA sac. We report 1-year results of the investigational device exemption pivotal trial.