Mechanisms of modulation of neuronal nicotinic receptors by substance P and OAG

Substance P is known to modulate neuronal nicotinicacetylcholine receptors (nAChRs) in the sympathetic nervous system.There are two conflicting proposals for the mechanism of this effect, an indirect action mediated by protein kinase C (PKC) and a direct interaction with receptor subunits. We studied the mechanisms of thiseffect in PC-12 cells. Substance P enhanced the decay of thenicotine-induced whole cell current. This effect was fast in its onsetand was not antagonized by guanosine5'-O-(2-thiodiphosphate), a G protein blocker, orstaurosporine, a nonselective PKC blocker. Staurosporine failed toreverse the inhibition by 1-oleoyl-2-acetyl-sn-glycerol (OAG), a synthetic diacylglycerol analog known to activate PKC. Theinhibitory effects of the peptide and OAG were preserved in excisedpatches, but substance P applied to the extra patch membrane wasineffective in the cell-attached patch configuration. We conclude thatsubstance P modulates neuronal nAChRs most likely by direct interactions with the receptors but independently from activation ofPKC or G proteins and that PKC does not participate in modulation by OAG.

     

Experimental subcutaneous granulomas in sheep with Dermatophilus-like microorganisms from porcine tonsil

The pathogenicity of the Dermatophilus-like microorganisms from porcine tonsil and the light and electron microscopic findings were studied with adult ewes. The early lesions were abscessess and advanced ones were granulomas after the subcutaneous inoculation. The granulomas were composed of the central bacterial colonies and the layers of the neutrophils, epithelioid cells and giant cells, and peripheral connective tissues. Epithelioid cells and giant cells were identified by the large euchromatic nuclei, abundant organelles and interdigitation of the blunt pseudopods in the ultrastructure. The lesions were very similar to subcutaneous granulomas in sheep and cattle due to Dermatophilus congolensis (atypical dermatophilosis), actinomycosis and nocardiosis.     

Isolation and characterization of arabinose mycolate from firmly bound lipids of mycobacteria

The glycolipid, d-arabinose-5-mycolate, was purified from bound lipids of mycobacteria. The significance of this glycolipid in the chemical structure of cell wall and wax D is discussed. The hypothetical chemical structure of mycolic acid-arabinogalactan portion of cell wall and wax D is proposed.     

Necessity of IgE antibodies and mast cells for manifestation of resistance against larval Haemaphysalis longicornis ticks in mice

Genetically mast cell-deficient WBB6F1-W/Wv mice showed an apparent defect in manifestation of the resistance against larval Haemaphysalis longicornis ticks, but their serum IgE levels increased more than 100-fold after the second tick infestation. Immune sera obtained from the WBB6F1-W/Wv mice were adoptively transferred to the other WBB6F1-W/Wv mice which had received intracutaneous injections of WBB6F1-+/+ mouse-derived cultured mast cells. Because the resistance against ticks was detectable only when both mast cells and IgE antibodies were available, immediate hypersensitivity reaction appeared to have a physiologic role in the manifestation of the resistance against H. longicornis ticks.     

Efficient production of IGG human monoclonal antibodies by lymphocytes stimulated by lipopolysaccharide,pokeweed mitogen,and interleukin 4

Summary Extensive screening of the mitogens lipopolysaccharide (LPS), pokeweed mitogen (PWM), andStaphylococcus aureus Cowan I (SAC I), alone and in combination and with and without interleukin (IL) was performed forin vitro activation of regional lymph node lymphocytes from lung cancer patients for the production of human IgG, IgM, and IgA. As assessed by electrofusion of the lymphocytes following their exposure to these agents with mouse myeloma cells and incubation of the fused hybridoma, a remarkable stimulatory effect was shown by LPS and particularly by LPS plus IL-4, which was substantially greater than that of either SAC I or PWM with or without various IL. Optimization studies indicated that the addition of PWM to LPS and IL-4 in the culture medium further stimulated the human antibody (Ab) production, and that the optimal formulation for stimulations of human IgG production was a culture medium containing 20 μg/ml of LPS, 1/500 of PWM, and 100 u/ml of IL-4.     

Serotonin in neuroblastoma × glioma NG108-15 hybrid cells

Mouse neuroblastoma × rat glioma NG108-15 hybrid cells contain a considerable amount of serotonin, and possess small but significant tryptophan hydroxylase activity. The results suggest that NG108-15 hybrid cells are serotonergic, in addition to the known cholinergic property.