Comparison of four procedures for measuring elastase production by Pseudomonas aeruginosa strains from cystic fibrosis patients.

Forty-five Pseudomonas aeruginosa strains were isolated from the sputa of cystic fibrosis patients. The elastase production of each strain was assayed in the culture supernatant using four different procedures, i.e.

Further studies on Pseudomonas aeruginosa LasA: analysis of specificity.

Full elastolytic activity in Pseudomonas aeruginosa is a result of the combined activities of elastase, alkaline proteinase, and the lasA gene product, LasA. The results of this study demonstrate that an active fragment of the LasA protein which is isolated from the culture supernatant fraction is capable of degrading elastin in the absence of elastase, thus showing that LasA is a second elastase produced by this organism. In addition, it is shown that LasA-mediated enhancement of elastolysis results from the separate activities of LasA and elastase upon elastin.

Differentiation between active and inactive human brucellosis by measuring antiprotein humoral immune responses.

A preparation of Brucella abortus cytoplasmic proteins was depleted of lipopolysaccharide (LPS) by immunoadsorption with a monoclonal antibody (MAb), BC68, specific for the O antigen of B. abortus smooth LPS. Two enzyme-linked immunosorbent assay (ELISA) systems were developed and used in this study.

Human aortic elastin from normal individuals and atherosclerotic patients: lipid and cation contents; susceptibility to elastolysis.

Aortic elastins, isolated from 30 humans of different ages, were purified by alkaline extraction, and separated into two groups depending on the presence of atherosclerotic plaques and calcification (grades 0 and 1). It was confirmed that the severity of atherosclerosis increases significantly with age (P less than 0.001) and elastin content decreases with atherosclerosis (P less than 0.

Hydrolysis of alanine oligomers and of elastin by P. aeruginosa proteinases and thermolysin.

The hydrolysis of alanine oligomers by P. aeruginosa proteinases, thermolysin and porcine pancreatic elastase was studied. The concentrations of substrates and cleavage products were determined using reverse phase high pressure liquid chromatography.

Human brucellosis: immunoblotting analysis of three Brucella abortus antigenic fractions allows the detection of components of diagnostic importance.

Results indicating that analysis of the immune humoral response of brucellosis patients by immunoblotting provides useful information for the characterization of antigenic fractions of possible diagnostic importance in human brucellosis are presented. Sera of 90 patients were obtained: 23 suffering from chronic brucellosis, 20 from acute brucellosis and 47 belonging to the group of serologically positive individuals (SPI) without clinical evidence of active infection at the time of examination, and 35 healthy volunteers. They were tested against three antigenic fractions: cytoplasmic (CYT), outer membrane (OM) and inner membrane (IM).

[Mechanism of action of proteinases of Pseudomonas aeruginosa].

Of the two proteases produced by Pseudomonas aeruginosa, one whose optimal pH is neutral, exhibits elastolytic activity. This elastase is produced as a prepropeptide, subsequently modified by proteolysis, and finally secreted as an active enzyme. Both proteases act mainly on hydrophobic aminoacids.

Common denominators in the etiology and pathology of visceral lesions of cystic fibrosis and Keshan disease.

The common denominator of a unique disseminated multi-focal miliary myocardial hyaline necrosis and fibrosis in Keshan disease (KSD) and cystic fibrosis (CF) and a commonality of the affected age groups of fetuses and preschool children led to the review of existing KSD autopsy material to search for pancreatic and hepatic lesions considered pathognomonic for CF. Pancreatic lesions considered pathognomonic for CF were found in 595, or 35% of 1700 documented cases of KSD. The pancreatic lesions were limited to tissues of fetuses and preschool children.

Elastolysis of kappa-elastin sub-fractions by pancreatic and leukocyte elastases.

Kappa-elastin peptides, obtained from insoluble elastin by organo-alkaline hydrolysis, were fractioned by gel filtration on Biogel agarose. Rates of hydrolysis by pancreatic and leukocyte elastases of the fractions were measured using a conductometric method. Kinetics obey to Michaelis-Menten model for both substrates and enzymes.

Micropreparative separation of peptides derived from sodium dodecyl sulphate-solubilized proteins.

A systematic investigation of the influence of the detergent sodium dodecyl sulphate (SDS) on micropreparative peptide separations on microbore reversed-phase high-performance liquid chromatographic columns is reported. A tryptic digest of bovine serum albumin and a mixture of synthetic peptides were used to monitor the separation behaviour of a 1.6 mm I.

Elastolytic activity of Pseudomonas aeruginosa elastase.

Elastolysis of insoluble elastin by Pseudomonas aeruginosa elastase was found to be less specific (higher apparent Km value) but more active (higher activity) than with pancreatic elastase. Furthermore, pancreatic and P. aeruginosa elastases act synergistically during the initial stages of elastolysis.

Automated conductimetric assay of human serum cholinesterase activity.

Serum cholinesterase activity was determined by conductimetry using samples in the microliter range. Butyrylcholine iodide was demonstrated to be a convenient substrate for the conductimetric assay. Validation of the microassay was made by using either purified enzyme or control serum.

Conductimetry: a new tool for studying inhibition of elastolysis.

The conductimetric method was applied to the measurement of human leukocyte elastase activity, using insoluble elastin as a substrate. From conductance changes, initial rates of elastolysis were derived. A linear relationship of enzyme activity with enzyme concentration was demonstrated up to 400nM of enzyme, for three different substrates.

Elastolysis of normal and partially cross-linked elastin.

Rate of elastolysis by pancreatic and leukocyte elastases of normal and copper deficient porcine aortic elastins were measured using a conductimetric method. Kinetics obey to Michaelis-Menten model for both substrates and enzymes. KM and Vmax values derived from Lineweaver-Burk plots indicate that, if a near uniformity exists in KM, differences were observed in catalytic rates, kcat increasing approximately 40% for copper deficient elastin elastolysis by leukocyte elastase.

Ca2+ and Mg2+ protection against thermal denaturation of pancreatic elastase.

Thermal denaturation of porcine pancreatic elastase was studied by difference spectrophotometry. At 293 nm, and pH 8.0, the thermal transition of elastase occurs with a midpoint temperature (Tm) of (58.

Microconductimetric assay of butyrylcholinesterase activity.

A conductimetric method for the assay of butyrylcholinesterase is described. A new conductimetric cell has been used which allows increased sensitivity. The physicochemical parameters (pH, buffer concentration) have been optimized.

Bulimia: theoretical conceptualizations and therapies.

Bulimia, a new entry in our system of nomenclature, has become more prevalent during the past decade and has stimulated a considerable amount of research. It still remains a theoretical and therapeutic puzzle in spite of a variety of efforts to conceptualize it. Treatment approaches are multitudinous and sometimes conflicting, partly due to problems in definition of the disorder, and the role of psychoanalysis is still unclear.

Lipase assay in duodenal juice using a conductimetric method.

Lipase activity in duodenal juice is known to undergo important variations in pathologic states, especially in cases of chronic pancreatitis. Almost all of the current assay methods are based on the measurement of hydrolysis of olive oil or triolein, mainly by potentiometry. As we have developed a conductimetric method for enzyme activity measurements, we have applied it to lipase assay.

Bilateral carotid artery occlusion resulting from giant cell arteritis.

A 65-year-old woman with subacute global deterioration of neurological function had bilateral occlusion of the internal carotid arteries demonstrated by angiography. Postmortem examination showed isolated giant cell arteritis involving the carotid siphon bilaterally.

Effects of static muscular contraction on impulse activity of groups III and IV afferents in cats.

Static contraction of the hindlimb muscles, induced by electrical stimulation of the ventral roots, reflexly increases arterial blood pressure and heart rate. Although stimulation of groups III and IV muscle afferents is believed to cause these reflex increases, the responses of these afferents to a level of static contraction that increases arterial pressure have not yet been determined. Therefore, in barbiturate-anesthetized cats, afferent impulses arising from endings in the gastrocnemius muscle were recorded from the L7 or S1 dorsal roots, while the cut peripheral end of the L7 ventral root was stimulated.

Anatomical localization of the cells of origin of efferent fibers in the superior laryngeal and recurrent laryngeal nerves of dogs.

Using horseradish peroxidase, we identified the cells of origin of motor fibers in the superior laryngeal and recurrent laryngeal nerves of dogs. Cells giving rise to fibers in the superior laryngeal nerve were found in the dorsal motor nucleus and the nucleus ambiguus, whereas cells giving rise to fibers in the recurrent laryngeal nerve were found in the nucleus ambiguus and nucleus retroambigualis, but usually not in the dorsal motor nucleus.

Effect of cycloheximide on corticosteroid-induced changes in colonic function.

Chronic parenteral mineralocorticoid and glucocorticoid treatment increases colonic sodium and water absorption and mucosal Na-K-ATPase activity. Cycloheximide, a protein synthesis inhibitor, was utilized to compare the mechanisms of action of these corticosteroids. Rats were injected with 50 or 100 micrograms/100 g body wet cycloheximide every 12 h, 0.

Cardiovascular responses elicited by hypothalamic stimulation in rabbits reveal a mediolateral organization.

Heart rate and blood pressure response patterns were elicited by relatively low intensity (approximately 0.2 mA) stimulation (10 s trains; 100 pulses/s; 0.25 ms pulse duration) in different regions of the hypothalamus in anesthetized rabbits.