Endotoxin-mediated pulmonary endothelial cell injury

Infusion of endotoxin into sheep results in physiological and structural damage to the pulmonary endothelium. It is uncertain whether complement activation and granulocyte sequestration in the pulmonary microcirculation and the ensuing granulocyte migration into the interstitium seen with endotoxemia contribute to the endothelial damage. We have shown that infusion of complement-activated plasma into sheep, although causing the same degree of granulocyte sequestration in the lungs, results in only modest and transient endothelial damage. In addition, migration or chemotaxis of granulocytes across the endothelial layer of intimal explants is not accompanied by either structural evidence of endothelial damage or a detectable increase in vascular permeability. Such studies indicate that neither complement/granulocyte activation nor granulocyte migration across a vessel wall is entirely responsible for the severe endothelial damage seen with endotoxin. In vitro studies of bovine pulmonary endothelial monolayers indicate that endotoxin can cause direct damage to the endothelium; the damage is dose-dependent and more severe in the presence of serum. Structural studies show endothelial cell retraction, pyknosis, and sloughing. Prostacyclin production and lactic dehydrogenase release are increased, as are permeability to small solutes and hydraulic conductance across the endothelium. It seems that endotoxin can cause a direct injury to pulmonary endothelium but complement and granulocyte activation may enhance the damage.     

Enthesopathies (lesions of muscular insertions) as indicators of the activities of neolithic Saharan populations

Enthesopathies are bony lesions involving the sites of insertion of muscles or ligaments. Those caused by hyperactivity of the relevant muscles may be distinguished clearly from those of metabolic or inflammatory origin. Observations from sporting and occupational medicine indicate that specific enthesopathies are correlated with different activities. Examination of the enthesopathies present on two groups of well-preserved neolithic skeletons from separate regions of the Sahara with different paleoenvironments show that overall 20% of the skeletons presented lesions. Three different forms of enthesopathy involved the arm, principally the elbow, and may be tentatively correlated with javelin throwing, wood cutting, and archery. Two types of lesion involving the foot were observed in skeletons from a hunter-gatherer population and may be correlated with much walking or running over hard ground. I suggest that the analysis of such lesions on ancient skeletons may, in concert with other archaeological data, throw light on the activities of ancient people.     

A binding assay for the solubilized receptors of type beta transforming growth factor: adsorption and removal of free ligand by dextran-coated charcoal

A binding assay was developed for the measurement of solubilized receptors for transforming growth factor type beta (TGF-beta). Solubilized receptors were incubated with 125I-TGF-beta, then the unbound ligand was removed by adsorption to dextran-coated charcoal. The binding of TGF-beta to solubilized receptors was saturable and specific, and increased in a linear manner with respect to the amount of membrane protein present. Crosslinking of radioactive complexes after adsorptive removal of unbound TGF-beta yielded complexes similar to affinity-labeled TGF-beta receptors from whole cells. Treatment of a 20% charcoal suspension with 0.2-0.4% dextran was optimal for the protection of receptors from adsorption to charcoal while allowing free TGF-beta to be removed; Mr approximately 250,000 dextran was most effective. This method can assay receptors from purified membranes and crude extracts of cells and tissues, and was used to demonstrate that TGF-beta receptors are glycosylated and retain a high affinity (Kd approximately 530 pM) for ligand after solubilization.     

Neurons of the central nervous system innervating the lips and oral area of the pond snail

By means of retrograde transport methods, CoCl2 and horseradish peroxidase, localization and morphological peculiarities of the CNS neurons, that innervate lips and oral area, have been studied in the pond snail (Gastropoda). The neurons, sending their processes into the anterior and middle labial nerves, are found nearly in all ganglia of the parapharyngeal nervous ring on the distal and ventral surface. In the cerebral ganglia they situate as several symmetrical groups. Among the neurons revealed, there are cells with rather local distribution of the terminal branches of the processes in the CNS neuropil and neurons with vast branching areas in the neuropil not only of its own ganglion, but also of the neighbouring ones. The problem concerning the zones of possible intersensory interaction in the cerebral ganglia is discussed and presence in them, together with complex reflectory arches, of bisegmental reflectory arches is considered.     

Spectroscopic analysis of acylated and deacylated myelin proteolipid protein

The effect of covalently bound fatty acid on the conformation of the myelin proteolipid protein has been studied by ultraviolet and intrinsic fluorescence spectroscopy. With dimethyl sulfoxide used as a perturbant, the exposure of Trp and Tyr residues in various mixtures of chloroform-methanol was evaluated by difference spectroscopy of the proteolipid protein (APL) and its chemically deacylated form (d-APL). The fraction of chromophoric groups exposed increased with the proportion of chloroform with 25% of the groups exposed in 1:2 chloroform-methanol and 98% in 3:1 chloroform-methanol. These conformational changes correlate well with changes in intrinsic viscosity. Values for the deacylated form were indistinguishable from those of the acylated protein, suggesting that fatty acids do not affect protein conformation in organic solvents. In water, UV difference spectroscopy indicated that the number of Tyr and Trp groups exposed in both APL and d-APL was relatively small and was independent of the molecular size of the perturbant. However, differences in the environment of the Trp groups in the two forms of the protein could be demonstrated by intrinsic fluorescence. When the protein was excited at 295 nm, the maximum emission wavelength for the acylated protein was 330 nm, whereas it was 335 nm for the deacylated form. Furthermore, the Trp groups in d-APL were more easily quenched by acrylamide than in APL, indicating that they were more exposed, or in a more hydrophilic environment, following deacylation. Protein aggregation appears to be independent of the presence of fatty acids, suggesting that the fluorescence differences between APL and d-APL are related to factors other than aggregation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Propranolol inhibits the compensatory increase in androgen secretion after unilateral orchidectomy in rats

Adrenergic antagonists were administered to rats by intratesticular injection at the time of unilateral orchidectomy and 5 h before autopsy, 24 h after surgery. Injections of the beta-receptor antagonist DL-propranolol (0.5 or 1.0 mg/injection) significantly inhibited the increase in the concentration of androgens in testicular vein plasma or interstitial fluid that occurred in unilaterally orchidectomized animals injected with vehicle. DL-Propranolol injections in animals with both testes did not reduce testicular or peripheral androgen concentrations or their increase after hCG administration. Injections of the less potent isomer (+)-propranolol or the alpha-receptor antagonist phentolamine did not inhibit the response to unilateral orchidectomy. It is concluded that the compensatory increase in androgen secretion induced by unilateral orchidectomy is, at least in part, the result of beta-adrenergic stimulation of steroidogenesis.     

Mineral licks as a sodium source for Isle Royale moose

Summary Natural mineral licks and their use by moose (Alces alces) on Isle Royale National Park, Michigan, were studied during 1982–85. The distribution of known licks suggested that they occurred in association with glacial debris, primarily in the western portions of the island. Moose utilized mineral springs extensively during the spring-summer period, and at least 5 licks were used year-round. During summer, a pronounced diel pattern of moose visitation was apparent, with peak use occurring between 0400–0800 h. Although daytime lick use declined by late June, morning and evening use continued to be relatively high throughout the study period. Peak lick use coincided with leaf-emergence in spring. Moose continued to utilize mineral licks despite the availability of ponds containing aquatic plants. Sodium appeared to be the element attracting moose to licks where they ingest copious amounts of water. Observed sodium ingestion rates (0.35 g/min) at licks indicate that licks provide a more concentrated source of sodium compared to aquatic plants (0.023 g/min). Based on the data presented, we reject the conclusions of earlier workers that aquatic plants constitute the only significant source of sodium for Isle Royale moose.     

Selection, mapping, and characterization of osmoregulatory mutants of Escherichia coli blocked in the choline-glycine betaine pathway.

Osmotically stressed Escherichia coli cells synthesize the osmoprotectant glycine betaine by oxidation of choline through glycine betaine aldehyde (choline----glycine betaine aldehyde----glycine betaine; B. Landfald and A.R. Str?m, J. Bacteriol. 165:849-855, 1986. Mutants blocked at the level of choline dehydrogenase were isolated by selection of strains which did not grow at elevated osmotic strength in the presence of choline but grew when supplemented with glycine betaine. A gene governing the choline dehydrogenase activity was named betA. Mapping by P1 transduction, F' complementation, and deletion mutagenesis showed the betA gene to be located at 7.5 min in the argF-codAB region of the chromosome. Mutants carrying deletions of this region also lacked glycine betaine aldehyde dehydrogenase activity and high-affinity uptake activity for choline; these deletions did not influence the activities of glycine betaine uptake or low-affinity choline uptake, both of which were osmotically regulated.     

Purification and characterization of poly(ADP-ribose) glycohydrolase. Different modes of action on large and small poly(ADP-ribose)

Poly(ADP-ribose) glycohydrolase was purified approximately 74,000-fold to apparent homogeneity from calf thymus with a yield of 3.2%. The enzyme was a monomeric protein of Mr = 59,000, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The action of glycohydrolase on poly(ADP-ribose) was exoglycosidic in the direction of adenosine terminus----ribose terminus; radioactive ADP-ribose monomers were immediately produced from evenly labeled poly(ADP-ribose), but not from the polymer labeled selectively at the ribose terminus. The enzymatic degradation of large poly(ADP-ribose) (greater than 20 ADP-ribose residues) proceeded in a biphasic as well as bimodal manner. In the early and rapid phase, the enzyme degraded part of large polymers successively, leaving the remainder completely intact, and accumulated ADP-ribose monomers and small polymers of the size less than half of original polymers, indicating that the enzyme action was processive up to a certain extent. In the late and 20-fold slower phase, by contrast, the enzyme degraded the accumulated small polymers gradually and evenly, i.e. in a nonprocessive manner. The Km for large polymers was approximately 100-fold lower than that for small polymers. Similar rates and processivities were observed with large and small polymers bound to various proteins. These results suggested that the glycohydrolase may regulate differentially the levels of large and small poly(ADP-ribose) in the cell.