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Gilad E, Matzkin H, Zisapel N. Inactivation of melatonin receptors by protein kinase C in human prostate epithelial cells. Endocrinology 1997; 138:4255-61. [PMID: 9322938 DOI: 10.1210/endo.138.10.5269] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The pineal hormone melatonin regulates seasonal reproduction and pubertal development in mammals. We recently found melatonin receptors in the human benign prostate tissue, primarily associated with the microsome-enriched fraction of the epithelial cells. In cultured benign prostate epithelial cells, melatonin, at physiological concentrations, suppressed [3H]thymidine incorporation and cGMP levels. The effects of melatonin were transient, suggesting inactivation of the receptors. In the present study, the possibility of inactivation of the prostate melatonin receptors by protein kinase C (PKC) was explored. Treatment of the microsome-enriched fraction with crude rat brain PKC in the presence of phorbol 12-myristate 13-acetate (TPA) or CaCl2 abolished the specific [125I]melatonin binding. This effect was prevented by the PKC inhibitor bisindolylmaleimide (GF-109203). [125I]Melatonin binding could be reinstated by iodoacetamide treatment. In benign prostate epithelial cells in culture, TPA pretreatment markedly reduced the apparent affinity of [125I]melatonin binding. In addition, TPA ablated the cells responses to melatonin, namely the suppression of [3H]thymidine incorporation and cGMP levels. Pretreatment with GF-109203 prevented the TPA effects on [125I]melatonin binding and responses. In addition, GF-109203 slowed down the inactivation of the melatonin-mediated inhibition of [3H]thymidine incorporation. Taken together, these data show that melatonin receptors are desensitized by PKC and imply that the transient response to melatonin may be the outcome of a direct or indirect melatonin-mediated activation of endogenous PKC.
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Cuzzocrea S, Zingarelli B, Gilad E, Hake P, Salzman AL, Szabó C. Protective effect of melatonin in carrageenan-induced models of local inflammation: relationship to its inhibitory effect on nitric oxide production and its peroxynitrite scavenging activity. J Pineal Res 1997; 23:106-16. [PMID: 9392449 DOI: 10.1111/j.1600-079x.1997.tb00342.x] [Citation(s) in RCA: 187] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In vitro studies have demonstrated that melatonin is a scavenger of oxyradicals and peroxynitrite and an inhibitor of nitric oxide (NO) production. In the present study, we evaluated the effect of melatonin treatment in two models of acute inflammation (carrageenan-induced paw edema and pleurisy), where oxyradicals, NO, and peroxynitrite play a crucial role in the inflammatory process. Our data show that melatonin (given at 62.5 and 125 microg/paw in the paw edema model or 25 and 50 mg/kg in the pleurisy model) inhibits the inflammatory response (paw swelling, pleural exudate formation, mononuclear cell infiltration, and histological injury) in dose-dependent manner in both models. Furthermore, our data suggest that melatonin exerts an inhibitory effect on the expression of the inducible isoform of NO synthase. Melatonin also prevented the formation of nitrotyrosine, an indicator of peroxynitrite, in both models of inflammation. Taken together, the present results demonstrate that melatonin exerts potent antiinflammatory effects. Part of these antiinflammatory effects may be related to an inhibition of the expression of the inducible NO synthase, while another part may be related to oxyradical and peroxynitrite scavenging.
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Gilad E, Zingarelli B, Salzman AL, Szabó C. Protection by inhibition of poly (ADP-ribose) synthetase against oxidant injury in cardiac myoblasts In vitro. J Mol Cell Cardiol 1997; 29:2585-97. [PMID: 9299380 DOI: 10.1006/jmcc.1997.0496] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Peroxynitrite and hydroxyl radical are reactive oxidants produced during myocardial reperfusion injury. In various cell types, including macrophages and smooth muscle cells, peroxynitrite and hydrogen peroxide cause DNA single strand breakage, which triggers the activation of the nuclear enzyme poly (ADP-ribose) synthetase (PARS), resulting in cytotoxicity. Using 3-aminobenzamide and nicotinamide, inhibitors of PARS, we investigated the role of PARS in the pathogenesis of myocardial oxidant injury in H9c2 cardiac myoblasts in vitro. Peroxynitrite (100-1000 microM), hydrogen peroxide (0.3-10 microM) and the NO donor compounds S-nitroso-N-accetyl-DL-penicillamine (SNAP) and diethyltriamine NONOate all caused a dose-dependent reduction of the mitochondrial respiration of the cells, as measured by the mitochondrial-dependent conversion of MTT to formazan. Peroxynitrite and hydrogen peroxide, but not the NO donors caused activation of cellular PARS activity. The suppression of mitochondrial respiration by peroxynitrite and hydrogen peroxide, but not by the NO donors, was ameliorated by pharmacological inhibition of PARS. The protection by the PARS inhibitors diminished at extremely high concentrations of the oxidants. Hypoxia (1 h) followed by reoxygenation (1-24 h) also resulted in a significant activation of PARS, and caused a suppression of mitochondrial respiration, which was prevented by inhibition of PARS. Similar to the results obtained with the pharmacological inhibitors of PARS, a fibroblast cell line which derives from the PARS knockout mouse was protected against the suppression of mitochondrial respiration in response to peroxynitrite and reoxygenation, but not to NO donors, when compared to the result of cells derived from wild-type animals. Based on our data, we suggest that activation of PARS plays a role in the myocardial oxidant injury.
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Gilad E, Matzkin H, Zisapel N. Interplay between sex steroids and melatonin in regulation of human benign prostate epithelial cell growth. J Clin Endocrinol Metab 1997; 82:2535-41. [PMID: 9253330 DOI: 10.1210/jcem.82.8.4134] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Human benign prostatic epithelial cells contain functional melatonin receptors that can suppress cell growth and viability. The development of benign prostatic hyperplasia in men is assumed to result from androgen-estrogen imbalance. The impact of sex steroids on melatonin receptors in human benign prostate epithelial cells was investigated. The suppression by melatonin of [3H]thymidine incorporation and cGMP, and the enhancement of cAMP levels in the cells were used as markers of melatonin responses. Dihydrotestosterone (DHT) and 17 beta-estradiol (E2) separately increased [3H]thymidine incorporation into the cells, but suppressed it when combined. In cells grown with DHT, melatonin responses were extenuated. E2 greatly reduced the apparent affinity of [125I]melatonin binding in these cells without affecting binding site density. In parallel, the ability of melatonin to suppress [3H]thymidine incorporation into the cells was ablated within 1 h after the addition of E2. The melatonin-mediated increase in cAMP and decrease in cGMP concentrations were also ablated by E2. Preincubation of the cells with bis-indolylmaleimide (GF 102903X), a specific inhibitor of protein kinase C, prevented the E2-mediated inactivation of melatonin binding and the inhibitory action on [3H]thymidine incorporation. Prolonged (18-h) incubation of the cells with phorbol 12-myristate 13-acetate to down regulate protein kinase activity, partially restored [125I]melatonin binding and responsiveness in the E2-treated cells. These data indicate that 1) DHT and E2 enhance prostate epithelial cells growth, but reduce cell growth when combined; 2) DHT extenuates the inhibitory effects of melatonin on epithelial cell growth; and 3) E2 acts to inactivate melatonin receptors and consequently responses in human epithelial benign prostatic hyperplasia cells. This process is probably mediated by protein kinase C. Together, these results show an interplay between melatonin and sex steroids in the regulation of benign prostatic epithelial cell growth.
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Gilad E, Shanas U, Terkel J, Zisapel N. Putative melatonin receptors in the blind mole rat harderian gland. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1997; 277:435-41. [PMID: 9134737 DOI: 10.1002/(sici)1097-010x(19970415)277:6<435::aid-jez3>3.0.co;2-p] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The blind mole rat (Spalax ehrenbergi) displays daily and seasonal rhythms. Melatonin, secreted nocturnally by the pineal gland, is also produced in the harderian gland and affects its morphology in rodents. We report here on the presence of putative melatonin receptors in the blind mole rat harderian gland, located in the microsome-enriched fraction of the cells. Equilibrium 125I-melatonin binding studies indicated high- and low-affinity melatonin binding sites in the female (apparent Kd 10 pM and 2.4 nM, respectively) and low-affinity sites in the male (apparent Kd 2.6 nM) mole rat. The binding sites were not significantly affected by season. Castration increased the density of high-affinity binding sites in males and low-affinity binding in females. 125I-melatonin binding to the gonadectomized mole rat preparation was inhibited by serotonin > 2-iodomelatonin > or = memelatonin > 5-methoxytryptamine. The guanine nucleotide analogs, guanosine 5'-O-[3-thio-triphosphate] and guanosine 5'-O-[2-thio-diphosphate], inhibited specific 125I-melatonin binding, whereas 5'-guanylyl imido-diphosphate was less potent. These results indicate for the first time the presence of GTP-sensitive melatonin binding sites in the blind mole rat harderian gland, and suggest that their expression is under control of sex steroids.
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Zingarelli B, Southan GJ, Gilad E, O'Connor M, Salzman AL, Szabó C. The inhibitory effects of mercaptoalkylguanidines on cyclo-oxygenase activity. Br J Pharmacol 1997; 120:357-66. [PMID: 9031736 PMCID: PMC1564467 DOI: 10.1038/sj.bjp.0700892] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
1. It has been proposed that in inflammatory conditions, in which both the inducible isoforms of nitric oxide synthase (iNOS) and cyclo-oxygenase (COX-2) are induced, inhibition of NOS also results in inhibition of arachidonic acid metabolism. In the present study we have investigated whether mercaptoalkylguanidines, a novel class of selective iNOS inhibitors, may also influence the activity of cyclo-oxygenase (COX). Therefore, the effect of mercaptoethylguanidine (MEG) and related compounds on the activity of the constitutive (COX-1) and the inducible COX (COX-2) was investigated in cells and in purified enzymes. Aminoguanidine, NG-methyl-L-arginine (L-NMA) and NG-nitro-L-arginine methyl ester (L-NAME) were also studied for comparative purposes. 2. Western blot analysis demonstrated a significant COX-1 activity in unstimulated J774 macrophages and in unstimulated human umbilical vein endothelial cells (HUVEC). Immunostimulation of the J774 macrophages by endotoxin (lipopolysaccharide of E. coli, LPS 10 micrograms ml-1) and interferon gamma (IFN gamma, 100 u ml-1) for 6 h resulted in a significant induction of COX-2, and a down-regulation of COX-1. No COX-2 immunoreactivity was detected in unstimulated HUVEC or unstimulated J774 cells. Therefore, in subsequent studies, the effect of mercaptoalkylguanidines on COX-1 activity was studied in HUVEC stimulated with arachidonic acid for 6 h, and in J774 cells stimulated with arachidonic acid for 30 min. The effect of mercaptoalkylguanidines on COX-2 activity was studied in immunostimulated J774 macrophages, both on prostaglandin production by endogenous sources, and on prostaglandin production in response to exogenous arachidonic acid stimulation. In addition, the effect of mercaptoalkylguanidines on purified COX-1 and COX-2 activities was also studied. 3. In experiments designed to measure COX-1 activity in HUVEC, the cells were stimulated by arachidonic acid (15 microM) for 6 h. This treatment induced a significant production of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha, the stable metabolite of prostacyclin), while nitrite production was undetectable by the Griess reaction. MEG (1 microM to 3 mM) caused a dose-dependent inhibition of the accumulation of 6-keto-PGF1 alpha, with an IC50 of 20 microM. However, aminoguanidine, L-NAME or L-NMA (up to 3 mM) did not affect the production of 6-keto-PGF1 alpha in this experimental system. In experiments designed to measure COX-1 activity in J774.2 macrophages, the cells were stimulated by arachidonic acid (15 microM) for 30 min; this also induced a significant production of 6-keto-PGF1 alpha and MEG (1 microM to 3 mM), aminoguanidine (at 1 and 3 mM), but neither L-NAME nor L-NMA inhibited the production of prostaglandins. 4. In experiments designed to measure prostaglandin production by COX-2 with endogenous arachidonic acid, J774.2 cells were immunostimulated for 6 h in the absence or presence of various inhibitors. In experiments designed to measure prostaglandin production by COX-2 with exogenous arachidonic acid, J774.2 cells were immunostimulated for 6 h, followed by a replacement of the culture medium with fresh medium containing arachidonic acid and various inhibitors. Both of these treatments induced a significant production of 6-keto-PGF1 alpha. Nitrite production, an indicator of NOS activity, was moderately increased after immunostimulation. MEG (1 microM to 3 mM) caused a dose-dependent inhibition of the accumulation of COX metabolites. Similar inhibition of LPS-stimulated 6-keto PGF1 alpha production was shown by other mercaptoalkylguanidines (such as N-methyl-mercaptoethylguanidine, N,N'-dimethyl-mercaptoethylguanidine, S-methyl-mercaptoethylguanidine and guanidino-ethyldisulphide), with IC50 values ranging between 34-55 microM. However, aminoguanidine, L-NAME and L-NMA (up to 3 mM) did not affect the production of prostaglandins.5. In comparative experiments indomethacin, a non selective COX inhibitor, and NS-398, a selective COX-2 inhibitor, reduced (LPS) stimulated 6-keto-PGF1alpha production in J774 macrophages in a dose-dependent manner without affecting nitrite release. Indomethacin, but not NS-398, inhibited 6-keto-PGF1alpha production in the HUVECs. 6.The inhibitory effect of MEG was due to direct inhibition of the catalytic activity of COX as indicated in experiments with purified COX-1 and COX-2. MEG dose-dependently inhibited the purified COX-1 and COX-2 activity with IC50 values of 33microM and 36microM, respectively. Aminoguanidine (at the highest concentrations) inhibited the formation of COX-1 metabolites, without affecting COX-2 activity. High doses of L-NAME (3mM) decreased COX-1 activity only, while L-NMA (up to 3mM) had no effect on the activity of either enzyme. 7.These results suggest that MEG and related compounds are direct inhibitors of the constitutive and the inducible cyclo-oxygenases, in addition to their effects on the inducible NOS. The additional effect of mercaptoalkylguanidines on COX activity may contribute to the beneficial effects of these agents in inflammatory conditions where both iNOS and COX-2 are expressed.
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Abstract
Peroxynitrite is a toxic oxidant formed from the reaction of superoxide and nitric oxide under conditions of inflammation and oxidant stress. Here we demonstrate that the pineal neurohormone melatonin inhibits peroxynitrite-mediated oxidant processes. Melatonin caused a dose-dependent inhibition of the oxidation of dihydrorhodamine 123 to rhodamine in vitro. Moreover, in cultured J774 macrophages, melatonin inhibited the development of DNA single strand breakage in response to peroxynitrite and reduced the suppression of mitochondrial respiration. Thus, melatonin appears to be a scavenger of peroxynitrite. This action may contribute to the antioxidant and antiinflammatory effects of melatonin in various pathophysiological conditions.
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Gilad E, Laudon M, Matzkin H, Pick E, Sofer M, Braf Z, Zisapel N. Functional melatonin receptors in human prostate epithelial cells. Endocrinology 1996; 137:1412-7. [PMID: 8625918 DOI: 10.1210/endo.137.4.8625918] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Melatonin, secreted nocturnally by the pineal gland, affects gonadal growth and pubertal development in rodents and, presumably, in humans. Recently, we have found, using 125I-labeled melatonin as a probe, specific melatonin binding sites in the human benign prostate tissue; these sites were primarily associated with the microsomal fraction of the epithelial cells. In the present study, we have explored 125I-melatonin binding sites in human benign prostate epithelial cells in culture and investigated the effects of melatonin on growth and viability of these cells. 125I-melatonin bound to the prostate cells with high (K(d) = 68 pM) affinity. Competition experiments revealed that specific binding was inhibited by subnanomolar concentrations of melatonin and 2-iodomelatonin, whereas serotonin and 5-methoxytryptamine reduced the binding only partially. Melatonin (10 pM-10 nM) inhibited the incorporation of 3H-thymidine and 3H-uridine into the prostate epithelial cells in a dose-dependent manner. Inhibition was transient, and the incorporation recovered to control levels within less than 24 h. Protein synthesis as measured by the incorporation of 35S-methionine into cell proteins decayed to minimal levels about 2 h after addition of melatonin, and its recovery was slower compared with that of 3H-thymidine or 3H-uridine incorporation. Melatonin treatment (1 nM) for 2-7 days inhibited cell growth and markedly increased the percentage of non-viable cells in culture, measured by the trypan blue exclusion assay. The results demonstrate high affinity melatonin receptors in the human benign prostate epithelial cells, which may affect cell growth and viability.
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Laudon M, Gilad E, Matzkin H, Braf Z, Zisapel N. Putative melatonin receptors in benign human prostate tissue. J Clin Endocrinol Metab 1996; 81:1336-42. [PMID: 8636329 DOI: 10.1210/jcem.81.4.8636329] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Melatonin, secreted by the pineal gland at night, inhibits pubertal development of rats and presumably men. In addition, it may directly suppress prostate growth in the adult rat. To investigate the possibility for a causal relationship between the age-related decline in melatonin production and increase in prevalence of benign prostate hypertrophy (BPH) in man, the presence of melatonin binding sites in human BPH tissue was examined. In vitro autoradiography indicated specific 125I-labeled melatonin (125I-melatonin) binding in the prostate, localized to the glandular epithelium. Separation and subcellular fractionation indicated that these sites were associated with the microsomal fraction of the epithelial cells. Kinetic and equilibrium 125I-melatonin binding experiments revealed that the binding was time dependent and reversible, with an apparent half saturation at 140 pmol/L. Competition experiments indicated high and low affinity melatonin binding sites; binding was inhibited by melatonin (IC50 1 nmol/L and 1 micromol/L, respectively) and partially by the putative melatonin antagonist, N-(2,4 dinitrophenyl)-5-methoxytryptamine (ML-23; IC50 0.1 nmol/L). Serotonin and 6-hydroxymelatonin were less potent, whereas up to 0.1 mmol/Lol/L of 5-methoxytryptamine, 6-methoxymelatonin, and tryptamine caused only a partial reduction in specific binding. The guanine nucleotide analogs, guanosine 5'-O-[3-thiotriphosphate] and guanosine 5'-O-[2-thio-diphosphate, inhibited specific 125I-melatonin binding, whereas 5'-guanylyl imidodiphosphate was less potent. The results indicate putative melatonin receptors in the human prostate epithelium.
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Gilad E, Zisapel N. High-affinity binding of melatonin to hemoglobin. BIOCHEMICAL AND MOLECULAR MEDICINE 1995; 56:115-20. [PMID: 8825074 DOI: 10.1006/bmme.1995.1066] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Determination of melatonin by radioimmunoassay in plasma samples from hemolyzed blood often yields flawed values. We studied the possibility that hemoglobin can bind melatonin and the iodinated tracer 125I-melatonin. The specific binding of 125I-melatonin to purified bovine hemoglobin was found to be rapid, saturable, and reversible (Kd = 315 pM, Bmax = 58 pmol/mg protein) and was inhibited by 2-iodomelatonin, serotonin, melatonin, and 5-methoxytryptamine. These data are compatible with the concept that hemoglobin can interfere with melatonin determinations by competing for melatonin and the iodinated tracer. Unlike melatonin receptor binding, the binding of 125I-melatonin to hemoglobin was not inhibited by guanine nucleotide analogs (i.e., GTP gamma S, GTP beta S, and Gpp(NH)p). Sodium cyanide had no effect on 125I-melatonin binding, indicating that 125I-melatonin does not bind to the heme group. On the other hand, 2,3-bisphosphoglycerate, at physiological concentrations (3-4 mM), decreased the apparent Bmax and Kd of 125I-melatonin binding to hemoglobin. These data suggest that 125I-melatonin binding to hemoglobin is conformation-specific and is unfavorable in the deoxyhemoglobin state. Hemoglobin may serve as a carrier protein for melatonin in the blood and discharge it in the target organs. Subsequently, the efficacy of melatonin's action as a hormone or antioxidant in target tissues may be enhanced.
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Gilad E, Paret G, Katz M, Vardi A, Kennet G, Barzilay Z. Plain radiography for diagnosis of gastrointestinal perforation in immune-compromised children--is it enough? MEDICAL AND PEDIATRIC ONCOLOGY 1995; 25:470-2. [PMID: 7565310 DOI: 10.1002/mpo.2950250609] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Gastrointestinal perforation is a surgical emergency in the pediatric patient and any delay in diagnosis might be hazardous. In immunocompromised children, the clinical signs of perforation may be blunted. We describe a child with acute lymphoblastic leukemia (ALL) and a perforated appendix and ileum in whom computerized tomography (CT) revealed extraluminal air that was not initially identified on plain abdominal film. Our case demonstrates the importance of early abdominal CT and ultrasound examination in detecting these potentially lethal complications.
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Paret G, Gilad E, Jonas A, Meyers JJ, Barzilay Z. Acute acalculous cholecystitis in an infant after cardiac surgery. J Pediatr Surg 1994; 29:1580-1. [PMID: 7877035 DOI: 10.1016/0022-3468(94)90223-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Acute acalculous cholecystitis is a virulent disease that occurs most commonly in critically ill patients. Imaging studies may facilitate earlier diagnosis and may decrease the morbidity and mortality rates. The authors report on a 30-month-old child with acute acalculous cholecystitis after surgical repair of tetralogy of Fallot. A review of the clinical pathogenesis, diagnosis, and treatment is included.
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Gilad E, Meidan R, Berman A, Graber Y, Wolfenson D. Effect of heat stress on tonic and GnRH-induced gonadotrophin secretion in relation to concentration of oestradiol in plasma of cyclic cows. JOURNAL OF REPRODUCTION AND FERTILITY 1993; 99:315-21. [PMID: 8107012 DOI: 10.1530/jrf.0.0990315] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Effects of acute and seasonal heat stress on tonic and GnRH-induced LH and FSH secretion were examined during the early follicular phase of the oestrous cycle of cows (n = 40). Prostaglandin F2 alpha was injected on day 11 +/- 1 of the oestrous cycle and on the next day blood samples were collected at intervals of 15-20 min for 14 h, and i.m. injection of GnRH was given after 7 h. Treatments compared were control versus acute heat stress during blood sampling in winter, and cooled versus chronic heat stress in summer. Before GnRH injection, chronic heat stress in summer did not affect basal concentrations of plasma LH, but did lower LH pulse amplitude. However, in cows with low plasma oestradiol (1.9 +/- 0.2 pg ml-1), the mean and basal concentrations and amplitude of tonic LH pulses were reduced by heat stress (3.1, 2.1 and 4.8 versus 1.9, 1.4 and 2.5 ng ml-1, respectively). In cows with high plasma oestradiol (6.3 +/- 0.5 pg ml-1), these parameters were not affected. In chronically heat stressed cows in summer, GnRH-induced increases in plasma LH and FSH concentrations were the same as in the cooled controls. However, in cows with low plasma oestradiol, mean concentrations of FSH in plasma (31.8 versus 25.5 ng ml-1), the peak of the GnRH-induced FSH and LH surge (FSH 47.4 versus 35.6 ng ml-1, LH 50.7 versus 37.3 ng ml-1) and the shape of the GnRH-induced FSH and LH curves (treatment by time interaction) were significantly lower in non-cooled versus cooled controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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Meidan R, Wolfenson D, Thatcher WW, Gilad E, Aflalo L, Greber Y, Shoshani E, Girsh E. Oxytocin and estradiol concentrations in follicular fluid as a means for the classification of large bovine follicles. Theriogenology 1993; 39:421-32. [PMID: 16727222 DOI: 10.1016/0093-691x(93)90385-i] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/1992] [Accepted: 10/18/1992] [Indexed: 10/26/2022]
Abstract
Large antral follicles (13 to 20 mm in diameter) were collected from ovaries of 109 cows and 17 heifers that also had a regressed corpus luteum at slaughter. Thirty percent of the animals had been injected once with prostaglandin F(2)alpha 48 hours before slaughter. Follicles were divided into 3 groups based on estradiol and oxytocin concentrations in the follicular fluid: Group I follicles, estradiol>/=100 ng/ml and oxytocin<65 pg/ml (preovulatory and assumed pre-gonadotropin surge); Group II follicles, estradiol<100 ng/ml and oxytocin>/=65 pg/ml (preovulatory and assumed post-gonadotropin surge); and Group III follicles, estradiol<100 ng/ml and oxytocin<65 pg/ml (atretic follicles). Treatment with prostaglandin F(2)alpha significantly increased the number of viable granulosa cells and estradiol content in Group I follicles. The estradiol: progesterone ratio was significantly higher in Group I vs Groups II and III, but it was similar for Group II healthy follicles and Group III atretic follicles. To ascertain the classification of follicles, PGF(2)alpha was administered on Day 6 of the cycle to induce corpus luteum regression, and a GnRH analog was administered 24 hours later. At 23 hours after GnRH analog treatment, follicular oxytocin levels significantly rose to 103 pg/ml. Concomitantly, estradiol concentrations fell to below 100 ng/ml. This response was not evident by 13 h after injection of the GnRH analog. The results indicate that follicular estradiol and oxytocin concentrations may be used as a means for the physiological classification of large bovine follicles.
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Kremer I, Gilad E, Kahan E, Derazne E, Bar-Ishak R. Necrosis and lymphocytic infiltration in choroidal melanomas. Acta Ophthalmol 1991; 69:347-51. [PMID: 1927318 DOI: 10.1111/j.1755-3768.1991.tb04826.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Patient survival, tumor lymphocytic infiltration and tumor necrosis were studied and evaluated in 43 enucleated eyes with the same histological diagnosis of spindle 'B' malignant melanoma of the choroid. A significant difference (P less than 0.05) was found between the survival rate of melanoma patients with no evidence of lymphocytic infiltration and/or necrosis in the tumor, compared to those with any evidence of of lymphocytic infiltration and/or tumor necrosis.
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David R, Tessler Z, Yagev R, Briscoe D, Biedner BZ, Gilad E, Yassur Y. Persistently raised intraocular pressure following extracapsular cataract extraction. Br J Ophthalmol 1990; 74:272-4. [PMID: 2354134 PMCID: PMC1042095 DOI: 10.1136/bjo.74.5.272] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In this population based study we have reviewed the files of all patients who underwent an extracapsular cataract extraction (ECCE) between 1984 and 1987, were normotensives prior to surgery, and were followed up for at least 10 months after the ECCE. From a total of 1047 operations 746 qualified for the inclusion criteria; of these, 16 (2.1%) were found to have a consistently raised intraocular pressure (greater than 21 mmHg) on more than two occasions) at four months or later after surgery and throughout at least a six-month period. An increased incidence of secondary aphakic glaucoma was associated with anterior chamber IOL implantation (p less than 0.001) and posterior capsule rupture (p less than 0.01), but not with any of the other variables examined (age, sex, surgeon).
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Kremer I, Gilad E, Ben-Sira I. Juxtapapillary Exophytic Retinal Capillary Hemangioma Treated by Yellow Krypton (568 nm) Laser Photocoagulation. Ophthalmic Surg Lasers Imaging Retina 1988. [DOI: 10.3928/1542-8877-19881001-13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Kremer I, Gilad E, Ben-Sira I. Juxtapapillary exophytic retinal capillary hemangioma treated by yellow krypton (568 nm) laser photocoagulation. OPHTHALMIC SURGERY 1988; 19:743-7. [PMID: 3194109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A 30-year-old man was found to have juxtapapillary exophytic capillary hemangioma complicated by circinate maculopathy and peripapillary exudative retinal detachment. The diagnosis was made from the appearance of the tumor and confirmed by fluorescein angiography. The presence of intermittent hematuria associated with a cystic kidney supported the diagnosis of von- Hippel-Lindau disease. subsequently, and attempt to treat the vascular lesion by yellow krypton (586 nm) laser photocoagulation failed to arrest the progression of the exudative retinal detachment, which finally became total.
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Biger Y, Gilad E, Khaimovitch J, Abulafia C. [Paratrachoma eye infection in Israel]. HAREFUAH 1987; 113:57-8. [PMID: 3692357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Nissenkorn I, Kremer I, Gilad E, Cohen S, Ben-Sira I. 'Rush' type retinopathy of prematurity: report of three cases. Br J Ophthalmol 1987; 71:559-62. [PMID: 3651370 PMCID: PMC1041226 DOI: 10.1136/bjo.71.7.559] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Three premature infants observed to develop severe stage III retinopathy of prematurity (ROP) at 3 to 5 weeks of age received immediate treatment by cryoablation and photocoagulation, with good results. The critical importance of the ophthalmic examination of premature babies from the age of 2 weeks, so as not to overlook such cases of 'rush' type ROP is stressed and the difficulty involved in treating such small neonates is discussed.
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Kremer I, Gilad E, Cohen S, Ben Sira I. Combined arterial and venous retinal occlusion as a presenting sign of systemic lupus erythematosus. Ophthalmologica 1985; 191:114-8. [PMID: 4058856 DOI: 10.1159/000309570] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A 22-year-old female was admitted to our department due to sudden loss of vision of her right eye. The funduscopic examination revealed a clinical picture of venous stasis retinopathy combined with macular branch artery occlusion. The physical examination and the laboratory tests confirmed the diagnosis of systemic lupus erythematosus.
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Snir M, Gilad E, Ben-Sira I. An unusual extraocular muscle anomaly in a patient with Crouzon's disease. Br J Ophthalmol 1982; 66:253-7. [PMID: 7066280 PMCID: PMC1039768 DOI: 10.1136/bjo.66.4.253] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A 29-year-old female suffering from Crouzon's disease was admitted to hospital with retinal detachment in the right eye. At operation agenesis of 4 extraocular muscles (superior and inferior recti and obliquus) was found, together with abnormal insertion of the 2 horizontal muscles. The same extraocular muscular abnormalities were found in the left eye. We suggest here a new surgical treatment in such cases and discuss the reasons for the limitation of ocular motility in such cases.
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Nissenkorn I, Yassur Y, Gilad E, Laron Z, Kauli R, Ben-Sira I. Keratopathy associated with hypoparathyroidism and Addison's disease. J Pediatr Ophthalmol Strabismus 1981; 18:28-30. [PMID: 7241303 DOI: 10.3928/0191-3913-19810301-07] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Two siblings suffering from keratopathy, one with hypoparathyroidism associated with Addison's disease and the other with Addison's disease alone, are described. The hypothesis that there was an autoimmune etiology with variant manifestations in each subject is suggested and discussed.
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