Paradoxical effects of elastase inhibitor guamerin on the tissue repair of two different wound models: sealed cutaneous and exposed tongue wounds.

Innate elastase inhibitors are known to be putatively involved in the regulation of tissue inflammation by inhibiting polymorphonuclear leukocyte (PMN) derived proteinases. The aim of this study was to evaluate affects of leukocyte elastase suppression and PMN infiltration on wound healing in mouse by administering the recombinant elastase inhibitor guamerin (rEIG) in two different wound models; 1) impaired pin-punctured dorsal mucosa of anterior tongue wound, 60 mice, treated with saline containing rEIG that were fed ad libitum and 2) stable linear excisional cutaneous wound, 40 mice, covered with fibrin sealant containing rEIG. The progress of healing was analyzed by histological methods. The tongue wounds treated with rEIG became edematous around the pin-punctured tongue wound, and influx of inflammatory cells and PMN into the underlying stromal tissue were seen rapidly after wounding and peaked between 2-4 days. Whereas the control mice showed almost no wheal formation in the pin-punctured wound, a far lesser levels of PMN infiltration, and almost complete wound closure in 4 days. In the other model, the liner excisional cutaneous wound treated with fibrin sealant containing rEIG showed early wound constriction, lesser degree of inflammatory cells influx, and complete reepithelialization in 4-5 days, whereas the wound of control mice with the fibrin sealant alone showed contrary delayed reepithelialization, greater degree of inflammatory cell infiltration, and consequencial formation of greater granulation tissue at wound site. Taken together, these data suggest paradoxical effects of rEIG on the wound healing where in the wound exposed to infiltrating milieu of microorganisms in the oral cavity, the rEIG aggravates the wound healing by interfering with other innate defensive factors and extended greater flux of PMNs to inflamed wound site, while in the wound enclosed by fibrin, the rEIG accelerated wound healing by inhibiting the inflammation-generated proteases and the acute inflammatory reaction.

Progressive potentiation of peptide release during a neuronal discharge.

1. In response to electrical stimulation, the bag cell neurons of Aplysia generate an afterdischarge that lasts 20-40 min. During this afterdischarge several neuroactive peptides are released. We have now studied the time course of release of two of these peptides, egg-laying hormone (ELH) and acidic peptide (AP). For the collection of released peptides, the artery to the bag cell clusters was perfused. The medium surrounding the clusters (artificial seawater, ASW) was completely exchanged at 5-min intervals before, during, and after stimulation of an afterdischarge. Peptides released into the external medium were analyzed with the use of high-pressure liquid chromatography. 2. Before stimulation, no detectable ELH and AP were found in the external medium. After the onset of an afterdischarge, the amount of ELH and AP released increased progressively until 15-20 min of firing. Toward the conclusion of an afterdischarge, the release of ELH and AP returned to control levels. 3. In contrast to the pattern of release of the peptides, the firing rate of the bag cell neurons is maximal within the first minute of afterdischarge and thereafter declines. 4. Release of the peptides from axonal varicosities occurs within the vascularized connective-tissue sheath that covers the clusters of bag cell neurons. Experiments were therefore carried out to establish whether the observed time course of release is affected by diffusion of the peptides through the vasculature into the external medium and, in particular, to determine whether the maximal rate of release at 15-20 min into the afterdischarge could be accounted for by a delay in transport of peptides from the neurites.(ABSTRACT TRUNCATED AT 250 WORDS)

Ecdysteroid receptors of the blowfly Calliphora vicina: partial purification and characterization of ecdysteroid binding.

A macromolecule with high affinity for the ecdysteroid analogue ponasterone A was isolated from nuclei of larvae of the blowfly Calliphora vicina. The ecdysteroid-binding molecule revealed characteristics of the moulting hormone receptor. It was sensitive towards protease but not towards nucleases. The nuclear protein had a limited binding capacity (0.2 pmol ponasterone A/mg protein), showed hormone analogue specificity and high affinity for ecdysteroids. Enzyme activities were present in the nuclear extract that metabolized ecdysteroids and thereby interfered with the binding assay. After their removal by DEAE-cellulose chromatography the ecdysteroid receptor preparation was stable at 20 degrees C for hours. This allowed a reliable determination of dissociation constants at equilibrium conditions. The hormone receptor complex had a KD of 1 nM, 30 nM, and 2000 nM with ponasterone A, 20-hydroxyecdysone, and ecdysone, respectively. The apparent molecular mass of the ecdysteroid receptor was 105,000 as determined by gel filtration.