Feline lentiviruses demonstrate differences in receptor repertoire and envelope structural elements

Feline immunodeficiency virus (FIV) causes fatal disease in domestic cats via T cell depletion-mediated immunodeficiency. Pumas and lions are hosts for apparently apathogenic lentiviruses (PLV, LLV) distinct from FIV. We compared receptor use among these viruses by: (1) evaluating target cell susceptibility; (2) measuring viral replication following exposure to specific and non-specific receptor antagonists; and (3) comparing Env sequence and structural motifs. Most isolates of LLV and PLV productively infected domestic feline T cells, but differed from domestic cat FIV by infecting cells independent of CXCR4, demonstrating equivalent or enhanced replication following heparin exposure, and demonstrating substantial divergence in amino acid sequence and secondary structure in Env receptor binding domains. PLV infection was, however, inhibited by CD134/OX40 antibody. Thus, although PLV and LLV infection interfere with FIV superinfection, we conclude that LLV and PLV utilize novel, more promiscuous mechanisms for cell entry than FIV, underlying divergent tropism and biological properties of these viruses.     

Antipyretic Effect of Neuropeptide Galanin in Endotoxin-Induced Fever

Neuropeptide galanin produces a antipyretic effect in experimental pyrogenic reaction induced by intraperitoneal injection of lipopolysaccharide. Central intracerebroventricular injection of 100 ng galanin significantly attenuated, but did not completely abolish fever. Central galanin injection potentiated endotoxin-induced activation of the noradrenergic system and blocked activation of the serotoninergic system of the anterior hypothalamus.     

A large outdoor radial maze for comparative studies in birds and mammals

For a comparative neurobiological analysis of spatial learning and memory, a large outdoor eight-arm radial maze was constructed which permits behavioral assessment of many avian and mammalian species both from the laboratory or the wild, using the same metric space and session schedules. It consists of a central part of 250cm diameter, and has arms of 650cm length, 170cm height and 80cm width. In order to determine appropriate training schedules for comparison of different species, we tested four mammalian and two avian species during 9-15 sessions: 18 albino rats (Rattus norvegicus), nine outdoors and nine in a conventional small indoor maze; six guinea pigs (Cavia porcellus); six rabbits (Oryctolagus cuniculus); five hedgehogs (Erinaceus europaeus); seven hooded crows (Corvus corone cornix) and six chickens (Gallus domesticus). Rats learned fast in both mazes yet significantly better in the large one. Good-to-excellent learning was also observed in juvenile rabbits and wild-caught crows, although the latter tended to avoid arms in the vicinity of the observer. Hedgehogs and chickens did not show significant learning as a group, but some individuals appeared to learn the task. Guinea pigs remained continuously passive and could not be trained. Thus, in spite of species-specific demands for reward, adaptation and pre-training, this type of radial maze permits to directly compare a wide variety of species. Such comparability is essential for an analysis of underlying neurobiological mechanisms.     

Synergistic effects in antigen capture ELISA using three monoclonal antibodies directed at different epitopes of the same antigen

Using a panel of monoclonal antibodies (mAb) against human myoglobin (Mb), we have shown that the sensitivity of antigen-capture enzyme-linked immunosorbent assay (ELISA) may be significantly increased by the simultaneous immobilization on a solid phase of two co-operating capture mAbs. This method ("a three-site ELISA") uses three mAbs at different epitopes of the same antigen (two capture/one tracer), unlike the traditional two-site assay, using one capture and one tracer mAbs. We established two-site and three-site ELISA assays for Mb, by varying capture and tracer mAbs. Three-site assays showed 4-6 fold increase in sensitivity, if compared with two-site assays. The model for the effect has been suggested, according to which in three-site ELISA the high-affinity cyclic configurations may be formed by an antigen, two-capture mAbs and the surface of solid phase.     

Immunohistochemical identification of hormonally-inactive tumors of the adrenal gland

An immunohistochemical study was carried out to differentiate between such neoplasms of the cortical and cerebral layers of the adrenal as adrenocortical tumor and pheochromocytoma. It used antibodies to chromogranin A, synaptophysin, vimentin, cytokeratin 8, pancytokeratin, carcinoembryonic antigen, epithelial membrane antigen, neurofilaments, alpha-fetoprotein, alpha-antitripsin and neuron-specific enolase. Chromogranin A and synaptophysin appeared to be immunohistochemical markers for pheochromocytoma since it responded negatively to vimentin and cytokeratin. Adenocortical tumors were associated with positive reaction to vimentin and a negative one to cytokeratin. These characteristics were used to differentiate adrenocortical tumors from adenomas which responded to cytokeratin and hardly to vimentin. A possibility of adrenal tumors consisting of endocrine and neurogenic cells is considered.     

Intraoperative computed EEG monitoring for evaluating the adequacy of general anesthesia

The article analyses the possibilities of computed EEG monitoring for evaluation of the magnitude and adequacy of the modern methods of general anesthesia: NLA, NLA with halothane inhalation, NLA including Kalipsol bolus administration. An original coefficient, called the adequacy index (AI), was found, which reflects the percentage contribution of deep rhythms (delta and theta) to the total power of the EEG in the range of 0 to 20 Hz. It is shown that the dynamics of this index correlates with the degree of the blocking of entry of sensory nociceptive information into the CNS. The lower boundary of AI-70% was determined, below which the generally accepted signs of anesthesia inadequacy appear: hyperactivity develops, a shift of pH in the acid direction occurs, and the base deficiency increases. It is suggested that determination of AI is used as a highly sensitive and operative test for routine monitoring of the patient's intraoperative condition and express diagnosis of inefficacy of anesthesia.