The Effects of Direct Instillations of a Therapeutic Mixture Into the Tracheobronchial Tree

Twenty-two patients with chronic productive bronchitis or bronchiectasis were treated by direct instillations of normal saline and N-acetylcysteine into the trachea through a percutaneous catheter following a period of conventional routine therapy.The instillation, using either normal saline or varying concentrations of N-acetylcysteine did not produce significant change in alveolar gas exchange as reflected by measurement of arterial PaCO₂ and the alveolar arterial gradient for oxygen during and after the introduction of the medication into the bronchial tree. Studies were carried out after patients had been stabilized breathing pure oxygen on an IPPB machine for 30 minutes.Evaluation of the treatment by means of pulmonary function tests demonstrated significant improvement in overall function following therapy.The results indicate that the technique of tracheobronchial lavage is physiologically benign and that overall improvement in pulmonary function can be obtained by this means in cases of the type described in this study.     

Morphological comparison ofSqualus blainvillei andS. megalops in the Eastern Atlantic,with notes on the genus

Morphological comparisons are made from the study of 64 specimens belonging to the following species:Squalus acanihias, S. blainvillei, S. megalops andS. acutirostris. The results suggest conspecificity betweenS. acutipinnis andS. megalops. The differences betweenS. blainvillei andS. megalops in the E-Atlantic are stressed. The Indo-Pacific species calledS. blainvillei by Chen et al. (1979) is regarded in this paper as probably an undescribed species. Some consideration on the status of several nominal species and the species grouping withinSqualus are also made.     

Endothelial and leukocyte forms of IL-8. Conversion by thrombin and interactions with neutrophils

We have recently shown that endothelial cell-derived IL-8 inhibits neutrophil adhesion to IL1-beta-activated human umbilical vein endothelial cell monolayers. IL-8 secreted by T lymphocytes or monocytes has been characterized as a promoter of neutrophil degranulation and chemotaxis. The IL-8 isolated from each of these cell types is a mixture of two IL-8 polypeptides, one consisting of 72 amino acids (herein called [ser-IL-8]72) and the other 77 amino acids (an N-terminal extended form herein called [ala-IL-8]77). IL-8 derived from T lymphocytes and monocytes is predominantly [ser-IL-8]72, whereas endothelial-derived IL-8 is highly enriched (greater than 80%) in [ala-IL-8]77. We address the relationship and activities of these two forms of IL-8 using recombinant proteins expressed by both mammalian cells and Escherichia coli. Thrombin was found to efficiently convert [ala-IL-8]77 to [ser-IL-8]72. In contrast, urokinase and tissue-type plasminogen activator were unable to cleave [ala-IL-8]77, and trypsin generated multiple IL-8 cleavage fragments. In competitive binding assays using 125I[ala-IL-8]77 neutrophils exhibited a twofold preference for [ser-IL-8]72 over [ala-IL-8]77. Both forms of IL-8 inhibited neutrophil adhesion to IL-1-beta-activated HUVEC monolayers by up to 90%. However, [ser-IL-8]72 was approximately 10-fold more potent than [ala-IL-8]77 in these assays (ED50 approximately 0.3 nM for [ser-IL-8]72 vs approximately 3 nM for [ala-IL-8]77. Both forms of IL-8 promoted degranulation of cytochalasin B-treated neutrophils [[ser-IL-8]72 (ED50 greater than 10 nM) was two- to three-fold more potent than [ala-IL-8]77], although in this regard they were less active than FMLP. Our data suggest that [ala-IL-8]77 and [ser-IL-8]72 have qualitatively similar and potentially complex biological activities, and that full activation of IL-8 requires cleavage to the [ser-IL-8]72 form. In the case of inflamed endothelial cells this activation could be mediated by thrombin generated in the procoagulant environment associated with these cells.     

The importance of mast cells for the neutrophil influx in immune complex-induced peritonitis in mice

The role of mast cells in polymorphonuclear leukocyte (PMN) influx in Ag-antibody complex-induced peritonitis was evaluated in mast cell-deficient WBB6F1-W/Wv (W/Wv) mice and their normal littermates, WBB6F1-+/+ (+/+). Peritoneal cell influx was evaluated after i.p. injection of preformed immune complexes. The first significant elevation in the PMN count over PBS-treated controls in +/+ mice was observed 2 h after stimulation. During the period of maximum leukocyte concentrations (6 to 10 h), the increase in total cell count was 5-fold and in PMN 25-fold. In W/Wv mice the PMN influx started 2 h later than in the +/+ mice, and the maximum response (8 to 10 h) was only 50% of that in controls. Reconstitution of mast cells in W/Wv mice for 2 wk or more restored the PMN response to immune complexes. Mast cell release due to AG-antibody complexes was evaluated by measuring fluorescence intensity after berberine sulfate staining for heparin in mast cells from unstimulated as well as stimulated +/+ mice. There was a significant decrease in fluorescence intensity as early as 15 min after stimulation. By 30 min the fluorescence intensity had declined by 65%. This indicates extensive mast cell release that started before PMN mobilization. These experiments demonstrate that mast cells make a significant contribution to immune complex-induced inflammation.     

Histamine Stimulation of Cyclic AMP Accumulation in Astrocyte-Enriched and Neuronal Primary Cultures from Rat Brain

Histamine stimulates cyclic AMP accumulation in astrocyte-enriched and neuronal primary cultures from rat brain in the presence of the phosphodiesterase inhibitor isobutylmethylxanthine. The response in the astrocyte cultures (Emax = 304 +/- 44% over basal, EC50 = 43 +/- 5 microM) was much higher than in neuronal cultures (Emax = 24 +/- 2%, EC50 = 14 +/- 7 microM). The histamine effect in astrocytes was competitively inhibited by the H2 antagonists cimetidine (Ki = 1.1 +/- 0.2 microM) and ranitidine (Ki = 46 +/- 10 nM) but was insensitive to the H1 antagonist mepyramine (1 microM). The two selective H2 agonists impromidine and dimaprit behaved as partial agonists and showed relative potencies (139 and 0.5, respectively) consistent with an interaction with H2 receptors. The more selective H1 agonist 2-thiazolylethylamine (0.01-1 mM) did not potentiate the response to impromidine (10 microM). Thus, in contrast to what is generally observed in intact cell preparations from brain, the histamine-induced cyclic AMP accumulation in astroglial cells is mediated solely by H2 receptors. The small effect shown in neuronal cultures also appears to be mediated by H2 receptors.     

Regulator and enzyme specificities of the TOL plasmid-encoded upper pathway for degradation of aromatic hydrocarbons and expansion of the substrate range of the pathway.

The TOL plasmid upper pathway operon encodes enzymes involved in the catabolism of aromatic hydrocarbons such as toluene and xylenes. The regulator of the gene pathway, the XylR protein, exhibits a very broad effector specificity, being able to recognize as effectors not only pathway substrates but also a wide variety of mono- and disubstituted methyl-, ethyl-, and chlorotoluenes, benzyl alcohols, and p-chlorobenzaldehyde. Benzyl alcohol dehydrogenase and benzaldehyde dehydrogenase, two upper pathway enzymes, exhibit very broad substrate specificities and transform unsubstituted substrates and m- and p-methyl-, m- and p-ethyl-, and m- and p-chloro-substituted benzyl alcohols and benzaldehydes, respectively, at a high rate. In contrast, toluene oxidase only oxidizes toluene, m- and p-xylene, m-ethyltoluene, and 1,2,4-trimethylbenzene [corrected], also at a high rate. A biological test showed that toluene oxidase attacks m- and p-chlorotoluene, albeit at a low rate. No evidence for the transformation of p-ethyltoluene by toluene oxidase has been found. Hence, toluene oxidase acts as the bottleneck step for the catabolism of p-ethyl- and m- and p-chlorotoluene through the TOL upper pathway. A mutant toluene oxidase able to transform p-ethyltoluene was isolated, and a mutant strain capable of fully degrading p-ethyltoluene was constructed with a modified TOL plasmid meta-cleavage pathway able to mineralize p-ethylbenzoate. By transfer of a TOL plasmid into Pseudomonas sp. strain B13, a clone able to slowly degrade m-chlorotoluene was also obtained.     

Quantitative phenotypical expression of three mutant genes in barley and the basis for defining an ideotype for Mediterranean environments

Summary Three mutants induced in the two-rowed barley variety Beka and their three binary recombinants have been used in an attempt to define an ideotype suitable for Mediterranean agroclimatic conditions. Physiological methods (classical plant growth analysis) together with the study of genotype x environment interaction for grain yield were used to characterize the genotypes. That characterization brought out the huge phenotypical variation produced by only three mutant genes, suggesting that single Mendelian genes may alone explain the quantitative variation, including grain yield, without the necessity of using the polygenic concept. The genotype best adapted to the environments studied is later in heading and has shorter straw and denser spikes than Beka; it also has higher inverse of leaf area rate and grain: leaf area ratio, a lower rate of leaf senescence, and a shorter grain filling period than the original variety.     

Overproduction of threonine by Saccharomyces cerevisiae mutants resistant to hydroxynorvaline.

In this work, we isolated and characterized mutants that overproduce threonine from Saccharomyces cerevisiae. The mutants were selected for resistance to the threonine analog alpha-amino-beta-hydroxynorvalerate (hydroxynorvaline), and, of these, the ones able to excrete threonine to the medium were chosen. The mutant strains produce between 15 and 30 times more threonine than the wild type does, and, to a lesser degree, they also accumulate isoleucine. Genetic and biochemical studies have revealed that the threonine overproduction is, in all cases studied, associated with the presence in the strain of a HOM3 allele coding for a mutant aspartate kinase that is totally or partially insensitive to feedback inhibition by threonine. This enzyme seems, therefore, to be crucial in the regulation of threonine biosynthesis in S. cerevisiae. The results obtained suggest that this strategy could be efficiently applied to the isolation of threonine-overproducing strains of yeasts other than S. cerevisiae, even those used industrially.     

Effects of acetic acid on the temperature profile of ethanol tolerance inSaccharomyces cerevisiae

Summary In a strain ofSaccharomyces cerevisiae, acetic acid at concentrations up to 1% (v/v) depressed the tolerance to added ethanol, from 11% (v/v) down to zero, and simultaneously narrowed the temperature range of growth from 3–42°C to 19–26°C. In addition, acetic acid shifted the associative temperature profile of growthand death to lower temperatures, and depressed the growth yield on glucose.