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S Regiani

Publications and source records attributed to S Regiani.

12 recordsLinked to original sources
PubMed1988

Expression of Mo3e antigen by cultured human umbilical vein endothelial cells (HUVEC) stimulated by phorbol myristate acetate (PMA) and related pharmacological inducers of protein kinase C.

Mo3e is a protease-sensitive membrane antigen (p75,50) selectively expressed by human monocytic cells (monocytes and U-937 cells) stimulated in vitro by exposure to a variety of activating factors, including phorbol diester compounds, bacterial lipopolysaccharide (LPS), and muramyl dipeptide (MDP)(R.F. Todd et al., J. Immunol. 135, 3869, 1985). Here we report that primary and multiply-passaged cultures of HUVEC also express the Mo3e determinant after stimulation by phorbol myristate acetate (PMA) and related inducers of protein kinase C. As measured in a radioimmunoassay of anti-Mo3e antibody binding to monolayer cultures of HUVEC, unstimulated cells bore little if any Mo3e. After culture for 4-120 hr in medium containing PMA, 4 beta-phorbol dibutyrate, 4 beta-phorbol didecanoate, or mezerein (each at a concentration of 81 nM), or 1-oleoyl-2-acetoyl-sn-3-glycerol (1 mM), HUVEC were found to selectively express the Mo3e determinant. The magnitude of expression was dependent upon the concentration of the stimulus, maximal by 24 hr, and inhibited by cycloheximide. The combination of PMA and the calcium ionophore, ionomycin, had an additive or synergistic effect on HUVEC Mo3e expression. The biologically inactive phorbol compounds 4 beta-phorbol and 4 alpha-phorbol didecanoate failed to stimulate Mo3e expression. Also inactive as inducers of HUVEC Mo3e expression were crude lymphokine and monokine supernatants, recombinant human lymphokines (interferon-gamma and interleukin-2), recombinant human monokines (interleukin-1 and tumor necrosis factor), bacterial cell wall products including LPS and MDP, pharmacologic agents that increase intracellular cyclic adenosine monophosphate (prostaglandin E2, cholera toxin, theophylline, isoproterenol and isobutylmethylxanthine), lectins (Con A and PHA), and heparin. These results indicate that Mo3e is an inducible plasma membrane antigen of not only mononuclear phagocytes but also cultured HUVEC.

Animals↗
PubMed1986

Brominating oxidants generated by human eosinophils.

Eosinophils are white blood cells that in humans are found in association with helminthic infections and various inflammatory disease processes. These cells contain a unique lysosomal peroxidase that oxidizes halides to generate highly reactive and toxic hypohalous acids. Although chloride is found in vivo at concentrations at least 1000-fold greater than those of other halides, human eosinophils did not preferentially oxidize chloride under physiologic conditions. Instead, eosinophils used bromide, a halide with a hitherto unknown function in humans, to generate a halogenating oxidant with characteristics similar, if not identical, to those of hypobromous acid. These results indicate that physiological concentrations of bromide arm human eosinophils with the ability to generate and release an unusual oxidant capable of destroying a wide range of prokaryotic and eukaryotic targets.

Bromates↗
PubMed1986

Oxidative regulation of neutrophil elastase-alpha-1-proteinase inhibitor interactions.

Triggered human neutrophils were able to maintain released elastase in an active form in the presence of purified alpha-1-proteinase inhibitor (alpha-1-PI), serum or bronchoalveolar lavage fluid (BAL). The accumulation of free elastase activity was associated with a decrease in the ability of the alpha-1-PI to inhibit porcine pancreatic elastase, an increase in proteinase activity associated with alpha-2-macroglobulin, and the oxidation of alpha-1-PI to a molecule containing four methionine sulfoxide residues. Neutrophils used both hypochlorous acid and long-lived N-chloroamines to oxidize the alpha-1-PI, but hypochlorous acid was preferentially used for suppressing the activity of the antiproteinase over short distances whereas the N-chloroamines were effective even when the phagocytes and alpha-1-PI were physically separated. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified alpha-1-PI, serum, or BAL that had been incubated with triggered neutrophils revealed that the released neutrophil elastase was not complexed with the antiproteinase and that a portion of the alpha-1-PI had undergone proteolysis. These data suggest that the presence of free neutrophil elastase as well as inactive, oxidized, and proteolyzed alpha-1-PI in fluids recovered from inflammatory sites in vivo could be directly mediated by triggered neutrophils alone.

Amino Acids↗
PubMed1986

Neutrophil-mediated solubilization of the subendothelial matrix: oxidative and nonoxidative mechanisms of proteolysis used by normal and chronic granulomatous disease phagocytes.

Both normal and chronic granulomatous disease (CGD) neutrophils were able to degrade the subendothelial matrix secreted by human endothelial cells via an elastase-dependent process. In the absence of the plasma antiproteinase, alpha-1-proteinase inhibitor (alpha-1-PI), normal neutrophils protect their released elastase from inactivation by using the chlorinated oxidants hypochlorous acid and endogenous N-chloroamines to suppress the antiproteinase's activity. In contrast, CGD neutrophils were unable to generate either class of chlorinated oxidant or to inactivate the porcine pancreatic elastase inhibitory capacity of alpha-1-PI unless the cells were supplemented with exogenous hydrogen peroxide. Despite the reliance of normal neutrophils on chlorinated oxidants to inactivate alpha-1-PI, neutrophils triggered in the presence of agents that block the generation of these reactive species continued to degrade the subendothelial matrix at a suppressed but significant rate in the presence of a 50-fold excess of the antiproteinase. The continued solubilization of the matrix by normal neutrophils was not due to the incomplete inhibition of oxidant generation because triggered CGD neutrophils were also able to degrade the matrix in the presence of excess alpha-1-PI. If CGD neutrophils were stimulated in the presence of an exogenous source of H2O2 and alpha-1-PI, the proteolytic potential of the cells was identical to that observed with normal stimulated neutrophils. We conclude that normal neutrophils can enhance their ability to degrade the subendothelial matrix by oxidatively protecting elastase from inactivation by alpha-1-PI but both normal and CGD neutrophils possess non-oxidatively linked mechanisms for sequestering and using elastase to mediate proteolytic effects in the presence of native antiproteinase.

Blood Proteins↗
PubMed1985

Reduction of pituitary GnRH receptors in immature rats treated with monosodium glutamate.

The number of pituitary gonadotropin-releasing hormone (GnRH) receptors increases during sexual maturation in the rat and probably reflects changes in hypothalamic GnRH secretion. As GnRH is synthesized in various hypothalamic nuclei, including the arcuate nucleas (ARC), we investigated the effects of monosodium glutamate (MSG)-induced lesions of the ARC in the rat. In males and females treated with MSG during the first 10 days of life, GnRH receptor content (GnRH-RC) was unchanged from controls at 10 days but was decreased at 20 and 30 days of age (P less than 0.01). Serum concentrations of luteinizing hormone (LH) were similar in MSG-treated and control males but were significantly lower in 10-day-old females (P less than 0.01). Injections of GnRH (3 micrograms every 8 h on days 18 and 19) restored GnRH-RC to control values in MSG-treated rats. Both MSG and untreated control rats showed similar LH responses to acute injections of GnRH, but responses were attenuated (P less than 0.05) after 2 days pretreatment with GnRH in rats that had received MSG. Ovarian GnRH-RC was similar in both MSG-treated and untreated controls. These data indicate that MSG-induced lesions of the ARC reduce pituitary GnRH-RC in immature rats, and the more marked effects in females suggest a more significant role in the ARC in the control of GnRH secretion during maturation in females. The lack of MSG-induced changes in ovarian GnRH-RC indicates that GnRH from the arcuate nucleus is not responsible for the increase in ovarian GnRH receptors seen during sexual maturation.

Animals↗
PubMed1984

Neutrophils degrade subendothelial matrices in the presence of alpha-1-proteinase inhibitor. Cooperative use of lysosomal proteinases and oxygen metabolites.

Triggered neutrophils rapidly degraded labeled matrices secreted by cultured, venous endothelial cells via a process dependent on elastase but not oxygen metabolites. In the presence of high concentrations of alpha-1-proteinase inhibitor, the ability of the stimulated neutrophil to solubilize the matrix was impaired. However, at lower concentrations of alpha-1-proteinase inhibitor the neutrophil could enhance the degradative potential of its released elastase by a H2O2-dependent process. Coincident with this increase in matrix damage, the stimulated neutrophil destroyed the elastase inhibitory activity of the alpha-1-proteinase inhibitor via a catalase-inhibitable process. The ability of the triggered neutrophil to solubilize the matrix in the presence of alpha-1-proteinase inhibitor was unaffected by superoxide dismutase or hydroxyl radical scavengers but was markedly impaired by catalase, azide, or hypochlorous acid scavengers. We conclude that neutrophils can cooperatively use an oxidant with characteristics similar, if not identical, to hypochlorous acid and the lysosomal proteinase elastase to negate the protective effects of alpha-1-proteinase inhibitor in order to attack the subendothelial matrix.

Cells, Cultured↗
PubMed1983

Opioids modulate pituitary receptors for gonadotropin-releasing hormone.

The number of pituitary GnRH receptors (GnRH-BC) is stable throughout the day in ovariectomized-estradiol treated rats, but undergo an acute transient reduction prior to the afternoon gonadotropin surge. To investigate the mechanisms controlling GnRH-BC we studied the effects of opioid-active compounds in this model. Morphine, given at 1400h, abolished both the LH surge and the preceding fall in GnRH-BC. Morphine given at 0900h increased GnRH-BC 30 min later, and this effect was abolished by simultaneous administration of naloxone. Naloxone alone produced an acute transient fall in GnRH-BC of similar magnitude to that seen before the spontaneous LH surge. These data suggest that alterations in endogenous opioid activity can modulate GnRH receptors and may form part of the mechanisms which initiate the afternoon gonadotropin surge.

Animals↗
PubMed1983

Gonadal regulation of pituitary gonadotropin-releasing hormone receptors during sexual maturation in the rat.

The number of pituitary GnRH receptors increases during sexual maturation in rats. In females, GnRH receptor content (GnRH-RC, femtomoles bound per gland) rises to a plateau (50 +/- 9 fmol) between 15-30 days of age before increasing further to 107 +/- 19 at 50 days. In males, GnRH-RC rises gradually to 140 +/- 9 fmol at 35 days, then remains stable through 60 days. Administration of estradiol or testosterone to immature females and males, respectively, inhibits the early rise in GnRH-RC. GnRH given for 2 days to steroid-treated immature animals restores receptor content to control levels. Neonatal castration in both sexes rapidly increases GnRH-RC and this response is maintained through 60 days of age. Castrations performed at different ages between 5-60 days showed a sex difference in GnRH-RC responses. Females exhibited a 2-fold increase in GnRH-RC by 5 days post castration at all ages studied. In males a similar increase in GnRH-RC was seen up to 25 days, but later diminished and no receptor response occurred when castration was performed between 30-45 days of age. Orchidectomy after 50 days again resulted in a 2-fold rise in GnRH-RC. GnRH injections (20 micrograms/day in divided doses) increased GnRH-RC in intact males at all ages studied. The same dosage did not increase GnRH receptors in 35-45 day male castrates and 5- to 10-fold higher doses were required to increase GnRH-RC indicating reduced receptor responsiveness to GnRH. Serum gonadotropins increased in response to castration at all ages in both sexes and did not parallel receptor responses in males. These data indicate that pituitary GnRH receptors are modulated by gonadal steroids from day 10 of life in both sexes and that the mechanism involves modification of hypothalamic GnRH secretion. Additionally, factor(s) other than gonadal steroids are operative in males during maturation which alter pituitary receptor responses to GnRH and result in discordant receptor and gonadotropin responses to GnRH.

Adrenalectomy↗
PubMed1980

Testicular GnRH receptors--characterization and localization on interstitial tissue.

Testicular GnRH membrane receptors were demonstrated using the non-degradable GnRH analog D-Ala6des-Gly10 GnRH ethylamide (D-Ala6) as ligand. Displaceable 125I D-Ala6 binding was present on crude membranes prepared from whole testes and interstitial tissue but not on the fractions from seminiferous tubules. 125I D-Ala6 binding to interstitial tissue was specific as only unlabeled D-Ala6 analog and synthetic GnRH inhibited binding of D-Ala6 tracer. Scatchard analysis of the analog data revealed a single high affinity binding site (Ka = 7 x 10(9) M-1) with a binding capacity of 200 +/- 10 (SE) fmol/mg membrane protein. In vivo treatment of both intact and hypophysectomized adult male rats with synthetic GnRH (6.6 microgram every 8 hr for 3 days) resulted in a 2-fold increase in GnRH binding capacity without change in receptor affinity. These results indicate that specific high affinity GnRH receptors are present only on interstitial tissue membrane fractions and receptor numbers are increased by a direct action of GnRH on the testis.

Animals↗
PubMedDate not supplied

A new concept in cancer care: the supportive care program.

This article describes the findings of a pilot program designed to enter advanced prostate cancer patients into the hospice benefit while they are still being actively treated, but in situations where treatment is known to be primarily palliative in nature. The supportive care program (SCP) combines the medical model's goal to prolong life with the goal of hospice to palliate symptoms and improve quality of life (QOL). The concept of a SCP was developed to create a team approach where advanced prostate cancer patients who are starting investigational chemotherapy are concurrently enrolled into a hospice program. The objectives were to identify whether SCP improved QOL and continuity of care while remaining cost-effective. Data were collected on patient quality of life, performance status, use of health care resources, and costs for the 36 enrolled patients. A comparison was made to a matched set of 23 control patients. Our findings indicate that the SCP contributes to continuity of care while being cost-effective.

Aged↗