Intratracheal instillation of a novel NO/nucleophile adduct selectively reduces pulmonary hypertension

Brilli, Richard J., Brian Krafte-Jacobs, Daniel J. Smith,Dominick Roselle, Daniel Passerini, Amos Vromen, Lori Moore, CsabaSzabó, and Andrew L. Salzman. Intratracheal instillation ofa novel NO/nucleophile adduct selectively reduces pulmonary hypertension. J. Appl. Physiol. 83(6):1968-1975, 1997.We examined the pulmonary and systemichemodynamic effects of administering soluble nitric oxide (NO) donorcompounds (NO/nucleophile adducts, i.e., NONOates) directly into thetrachea of animals with experimentally induced pulmonary hypertension.Steady-state pulmonary hypertension was created by using thethromboxane agonist U-46619. Yorkshire pigs were randomly assigned toone of four groups: group 1,intratracheal saline (control; n = 8);group 2, intratracheal sodiumnitroprusside (n = 6);group 3, intratracheal ethylputreanineNONOate (n = 6); andgroup 4, intratracheal2-(dimethylamino)-ethylputreanine NONOate (DMAEP/NO;n = 6). Pulmonary and systemichemodynamics were monitored after drug instillation.Group 4 had significant reductions in pulmonary vascular resistance index (PVRI) at all time points comparedwith steady state and compared with group1 (P < 0.05), whereas systemic vascular resistance index did not change. The meanchange in mean pulmonary arterial pressure in group4 was 33.1 ± 1.2% compared with +6.4 ± 1.3% in group 1 (P < 0.001), and the mean change inmean arterial pressure was 9.3 ± 0.7% compared with acontrol value of 0.9 ± 0.5%(P < 0.05). Groups 2 and 3 hadsignificant decreases in both PVRI and systemic vascular resistanceindex compared with steady state and with group1. In conclusion, intratracheal instillation of apolar-charged tertiary amine NONOate DMAEP/NO results in the selectivereduction of PVRI. Intermittent intratracheal instillation of selectiveNONOates may be an alternative to continuously inhaled NO in thetreatment of pulmonary hypertension.

     

Hormonal imprinting in cell culture II. Evidence of hormonal imprinting and thyrotropin (TSH) -gonadotropin (FSH) overlap in a Chinese hamster ovary (CHO) cell line

Reexposure of cultures of the Chinese hamster ovarian cell line CHO K1 to FITC-labeled hormone 48 h after the first 24-h exposure to FSH or TSH showed that hormonal imprinting, accounting for a greater binding capacity on reexposure, also took place in in vitro conditions. TSH amplified the receptors of FSH to a greater degree than FSH itself, although the reverse effect failed to happen. TSH was able to bind the ovarian cells at first exposure, and to amplify the receptors for itself and--remarkably--to a considerably greater degree for FSH, exactly as observed earlier in in vivo systems.     

Study of the imprinting and overlap of insulin and concanavalin-A at the receptor level in a protozoan (Tetrahymena) model system

In a protozoan (Tetrahymena) model system, insulin treatment produced a long-term imprinting which upon re-exposure to the hormone resulted in an enhanced binding of the hormone. Insulin pretreatment produced similar effect with regard to the binding of concanavalin-A. Concanavalin-A could only induce a short-term imprinting for itself and was not capable at all of inducing imprinting for insulin. Based on the results of this study it appears that the binding of the sugar component of the receptor, which can be achieved also by lectin, is not sufficient to induce imprinting but the whole (hormone) molecule is needed.     

Enhancement of the sensitivity of Tetrahymena to a second hormonal influence by hormone pretreatment

Diiodotyrosine and serotonin enhance the growth of Tetrahymena. A second exposure of the unicellular to these hormones accounts for a still greater increase of its growth rate, probably due to the amplification of the receptor induced by the first exposure.     

The effect of cyclic AMP on the maturation and degranulation of mast cells.

In short-term tissue cultures dibutyryl cAMP inhibits the cortisone-induced degranulation of mast cells. The effect of methylxanthine was found to be similar but developed at a slower rate. The increase of cAMP level also affected the maturation of mast cells, as the ratio of cells of mixed granulation increased, compared to the alcian blue- and safranin-present model inhibited degranulation.     

Evidence of the heterogeneity of mast cell population based on their biogenic amine content

The heterogeneity of the mast cells localized in various organs has been demonstrated by histochemical determination in their indole amine and histamine content. The strongest amine reaction was found in the mast cells in the mesenterium and peritoneal fluid where their maturation occurs. The reaction of the subcutaneous connective tissue is weaker; in the thyroid gland the reaction is weak as well as diffuse. In the thymus the mast cells localized along the vessels give a strong histamine reaction. The experiments support previously published data concerning the heterogeneity of mast cell populations.     

Involvement of the phosphoinositol (PI) system in the mechanism of hormonal imprinting

Certain components of the phosphoinositol (PI) system are present in the unicellular Tetrahymena. Treatment of Tetrahymena with insulin did not alter the relative proportions of the examined six phospholipid components (PIP2, PIP, phosphatidylcholine, phosphatidylethanolamine, PI, PA), but the primary interaction (imprinting) with insulin accounted for an about 75% decrease in the PIP2-level and an about 20% increase in the phosphatidylethanolamine level. The experimental results strongly suggest that hormonal imprinting accounted for adjustment of the second messenger systems of Tetrahymena to an energy saving level.     

Influence of hormone concentration and time factor on development of receptor memory in a unicellular (Tetrahymena) model system

1. Treatment of Tetrahymena pyriformis cells with diiodotyrosine (T2) gave rise to a considerable, concentration-dependent increase of the growth rate within the range of 10(-15) and 10(-9) M, but did not influence it at the level of 10(-18) M. 2. Re-exposure of the cells 1, 2 and 4 weeks later to the hormone concentrations originally used accounted for a marked increase of growth rate at all hormone levels tested, indicating that the extremely low concentration of 10(-18) M, which failed to stimulate growth on first exposure, did nevertheless give rise to hormonal imprinting, which caused the cells to "remember" the hormone, as judged from their increased responsiveness to it on re-exposure. 3. The degree of growth response was concentration-dependent on both first and second exposure: higher levels of treatment gave rise to firmer imprinting, and to greater response on re-exposure. 4. The length of exposure time proved to be more decisive than the level of treatment in respect of the development of hormonal imprinting. 5. Short-term exposures up to 60 min, although they stimulated cell growth by direct effect, gave rise to lasting inhibition of cellular response to re-exposure(s) rather than to hormonal imprinting.     

Cloning of mtDNA fragments homologous to mitochondrial S2 plasmid-like DNA in maize

Summary Mitochondria from S-type cytoplasmic male-sterile maize contain two small DNA species, S1 and S2, which are absent from other fertile and male-sterile cytoplasms. These species have been cloned in plasmid pBR322 by the homopolymer extension method. Probes made with these recombinant plasmids have been used to establish the homology between high molecular weight mitochondrial DNAs of fertile and male-sterile cytoplasms, and small mitochondrial plasmid-like molecules. Hybridization and mapping data show that S2 DNA copies are homologuous with sequences of the normal mitochondrial genome. A comparison of physical maps of different isolated mtDNA fragments indicates a heterogeneous arrangement of S2 sequences in the mtDNA population of normal fertile maize cytoplasm. The origin of this heterogeneity is discussed.